Low-bit rate feedback strategies for iterative IA-precoded MIMO-OFDM-based systems.

PubMed

Teodoro, Sara; Silva, Adão; Dinis, Rui; Gameiro, Atílio

2014-01-01

Interference alignment (IA) is a promising technique that allows high-capacity gains in interference channels, but which requires the knowledge of the channel state information (CSI) for all the system links. We design low-complexity and low-bit rate feedback strategies where a quantized version of some CSI parameters is fed back from the user terminal (UT) to the base station (BS), which shares it with the other BSs through a limited-capacity backhaul network. This information is then used by BSs to perform the overall IA design. With the proposed strategies, we only need to send part of the CSI information, and this can even be sent only once for a set of data blocks transmitted over time-varying channels. These strategies are applied to iterative MMSE-based IA techniques for the downlink of broadband wireless OFDM systems with limited feedback. A new robust iterative IA technique, where channel quantization errors are taken into account in IA design, is also proposed and evaluated. With our proposed strategies, we need a small number of quantization bits to transmit and share the CSI, when comparing with the techniques used in previous works, while allowing performance close to the one obtained with perfect channel knowledge.

System identification of closed-loop cardiovascular control mechanisms: diabetic autonomic neuropathy

NASA Technical Reports Server (NTRS)

Mukkamala, R.; Mathias, J. M.; Mullen, T. J.; Cohen, R. J.; Freeman, R.

1999-01-01

We applied cardiovascular system identification (CSI) to characterize closed-loop cardiovascular regulation in patients with diabetic autonomic neuropathy (DAN). The CSI method quantitatively analyzes beat-to-beat fluctuations in noninvasively measured heart rate, arterial blood pressure (ABP), and instantaneous lung volume (ILV) to characterize four physiological coupling mechanisms, two of which are autonomically mediated (the heart rate baroreflex and the coupling of respiration, measured in terms of ILV, to heart rate) and two of which are mechanically mediated (the coupling of ventricular contraction to the generation of the ABP wavelet and the coupling of respiration to ABP). We studied 37 control and 60 diabetic subjects who were classified as having minimal, moderate, or severe DAN on the basis of standard autonomic tests. The autonomically mediated couplings progressively decreased with increasing severity of DAN, whereas the mechanically mediated couplings were essentially unchanged. CSI identified differences between the minimal DAN and control groups, which were indistinguishable based on the standard autonomic tests. CSI may provide a powerful tool for assessing DAN.

Multifractal property of Chinese stock market in the CSI 800 index based on MF-DFA approach

NASA Astrophysics Data System (ADS)

Zhu, Huijian; Zhang, Weiguo

2018-01-01

CSI 800 index consists of CSI 500 index and CSI 300 index, aiming to reflect the performance of stocks with large, mid and small size of China A share market. In this paper we analyze the multifractal structure of Chinese stock market in the CSI 800 index based on the multifractal detrended fluctuation analysis (MF-DFA) method. We find that the fluctuation of the closing logarithmic returns have multifractal properties, the shape and width of multifractal spectrum are depended on the weighing order q. More interestingly, we observe a bigger market crash in June-August 2015 than the one in 2008 based on the local Hurst exponents. The result provides important information for further study on dynamic mechanism of return fluctuation and whether it would trigger a new financial crisis.

High Fill Factors of Si Solar Cells Achieved by Using an Inverse Connection Between MOS and PN Junctions.

PubMed

Wang, Liang-Xing; Zhou, Zhi-Quan; Zhang, Tian-Ning; Chen, Xin; Lu, Ming

2016-12-01

Fill factors (FFs) of ~0.87 have been obtained for crystalline Si (c-Si) solar cells based on Ag front contacts after rapid thermal annealing. The usual single PN junction model fails to explain the high FF result. A metal/oxide/semiconductor (MOS) junction at the emitter is found to be inversely connected to the PN one, and when its barrier height/e is close to the open-circuit voltage of the solar cell, very high FF is obtainable. In this work, although the open-circuit voltage (<580 mV) is not high here, the efficiency of c-Si solar cell still reaches the state-of-the-art value (>20 %) due to the high FF achieved.

Electronic structure and optical properties of CsI, CsI(Ag), and CsI(Tl)

NASA Astrophysics Data System (ADS)

Zhang, Zheng; Zhao, Qiang; Li, Yang; Ouyang, Xiao-Ping

2016-05-01

The band structure, electronic density of states and optical properties of CsI and of CsI doped with silver or thallium are studied by using a first-principles calculation based on density functional theory (DFT). The exchange and the correlation potentials among the electrons are described by using the generalized gradient approximation (GGA). The results of our study show that the electronic structure changes somewhat when CsI is doped with silver or thallium. The band gaps of CsI(Ag) and CsI(Tl) are smaller than that of CsI, and the width of the conduction band of CsI is increased when CsI is doped with thallium or silver. Two peaks located in the conduction band of CsI(Ag) and CsI(Tl) are observed from their electronic densities of states. The absorption coefficients of CsI, CsI(Ag), and CsI(Tl) are zero when their photon energies are below 3.5 eV, 1.5 eV, and 3.1 eV, respectively. The results show that doping can improve the detection performance of CsI scintillators. Our study can explain why doping can improve the detection performance from a theoretical point of view. The results of our research provide both theoretical support for the luminescent mechanisms at play in scintillator materials when they are exposed to radiation and a reference for CsI doping from the point of view of the electronic structure.

Voltage Sensor Inactivation in Potassium Channels

PubMed Central

Bähring, Robert; Barghaan, Jan; Westermeier, Regina; Wollberg, Jessica

2012-01-01

In voltage-gated potassium (Kv) channels membrane depolarization causes movement of a voltage sensor domain. This conformational change of the protein is transmitted to the pore domain and eventually leads to pore opening. However, the voltage sensor domain may interact with two distinct gates in the pore domain: the activation gate (A-gate), involving the cytoplasmic S6 bundle crossing, and the pore gate (P-gate), located externally in the selectivity filter. How the voltage sensor moves and how tightly it interacts with these two gates on its way to adopt a relaxed conformation when the membrane is depolarized may critically determine the mode of Kv channel inactivation. In certain Kv channels, voltage sensor movement leads to a tight interaction with the P-gate, which may cause conformational changes that render the selectivity filter non-conductive (“P/C-type inactivation”). Other Kv channels may preferably undergo inactivation from pre-open closed-states during voltage sensor movement, because the voltage sensor temporarily uncouples from the A-gate. For this behavior, known as “preferential” closed-state inactivation, we introduce the term “A/C-type inactivation”. Mechanistically, P/C- and A/C-type inactivation represent two forms of “voltage sensor inactivation.” PMID:22654758

Effects of haloperidol on Kv4.3 potassium channels.

PubMed

Lee, Hong Joon; Sung, Ki-Wug; Hahn, Sang June

2014-10-05

Haloperidol is commonly used in clinical practice to treat acute and chronic psychosis, but it also has been associated with adverse cardiovascular events. We investigated the effects of haloperidol on Kv4.3 currents stably expressed in CHO cells using a whole-cell patch-clamp technique. Haloperidol did not significantly inhibit the peak amplitude of Kv4.3, but accelerated the decay rate of inactivation of Kv4.3 in a concentration-dependent manner. Thus, the effects of haloperidol on Kv4.3 were estimated from the integral of the Kv4.3 currents during the depolarization pulse. The Kv4.3 was decreased by haloperidol in a concentration-dependent manner with an IC50 value of 3.6 μM. Haloperidol accelerated the decay rate of Kv4.3 inactivation and activation kinetics in a concentration-dependent manner, thereby decreasing the time-to-peak. Haloperidol shifted the voltage dependence of the steady-state activation and inactivation of Kv4.3 in a hyperpolarizing direction. Haloperidol also caused an acceleration of the closed-state inactivation of Kv4.3. Haloperidol produced a use-dependent block of Kv4.3, which was accompanied by a slowing of recovery from the inactivation of Kv4.3. These results suggest that haloperidol blocks Kv4.3 by both interacting with the open state of Kv4.3 channels during depolarization and accelerating the closed-state inactivation at subthreshold membrane potentials. Copyright © 2014 Elsevier B.V. All rights reserved.

Three-Dimensional Numerical Simulations of Equatorial Spread F: Results and Observations in the Pacific Sector

NASA Technical Reports Server (NTRS)

Aveiro, H. C.; Hysell, D. L.; Caton, R. G.; Groves, K. M.; Klenzing, J.; Pfaff, R. F.; Stoneback, R.; Heelis, R. A.

2012-01-01

A three-dimensional numerical simulation of plasma density irregularities in the postsunset equatorial F region ionosphere leading to equatorial spread F (ESF) is described. The simulation evolves under realistic background conditions including bottomside plasma shear flow and vertical current. It also incorporates C/NOFS satellite data which partially specify the forcing. A combination of generalized Rayleigh-Taylor instability (GRT) and collisional shear instability (CSI) produces growing waveforms with key features that agree with C/NOFS satellite and ALTAIR radar observations in the Pacific sector, including features such as gross morphology and rates of development. The transient response of CSI is consistent with the observation of bottomside waves with wavelengths close to 30 km, whereas the steady state behavior of the combined instability can account for the 100+ km wavelength waves that predominate in the F region.

Structural model of the open–closed–inactivated cycle of prokaryotic voltage-gated sodium channels

PubMed Central

Bagnéris, Claire; Naylor, Claire E.; McCusker, Emily C.

2015-01-01

In excitable cells, the initiation of the action potential results from the opening of voltage-gated sodium channels. These channels undergo a series of conformational changes between open, closed, and inactivated states. Many models have been proposed for the structural transitions that result in these different functional states. Here, we compare the crystal structures of prokaryotic sodium channels captured in the different conformational forms and use them as the basis for examining molecular models for the activation, slow inactivation, and recovery processes. We compare structural similarities and differences in the pore domains, specifically in the transmembrane helices, the constrictions within the pore cavity, the activation gate at the cytoplasmic end of the last transmembrane helix, the C-terminal domain, and the selectivity filter. We discuss the observed differences in the context of previous models for opening, closing, and inactivation, and present a new structure-based model for the functional transitions. Our proposed prokaryotic channel activation mechanism is then compared with the activation transition in eukaryotic sodium channels. PMID:25512599

Distortion outage minimization in Nakagami fading using limited feedback

NASA Astrophysics Data System (ADS)

Wang, Chih-Hong; Dey, Subhrakanti

2011-12-01

We focus on a decentralized estimation problem via a clustered wireless sensor network measuring a random Gaussian source where the clusterheads amplify and forward their received signals (from the intra-cluster sensors) over orthogonal independent stationary Nakagami fading channels to a remote fusion center that reconstructs an estimate of the original source. The objective of this paper is to design clusterhead transmit power allocation policies to minimize the distortion outage probability at the fusion center, subject to an expected sum transmit power constraint. In the case when full channel state information (CSI) is available at the clusterhead transmitters, the optimization problem can be shown to be convex and is solved exactly. When only rate-limited channel feedback is available, we design a number of computationally efficient sub-optimal power allocation algorithms to solve the associated non-convex optimization problem. We also derive an approximation for the diversity order of the distortion outage probability in the limit when the average transmission power goes to infinity. Numerical results illustrate that the sub-optimal power allocation algorithms perform very well and can close the outage probability gap between the constant power allocation (no CSI) and full CSI-based optimal power allocation with only 3-4 bits of channel feedback.

The Langley Research Center CSI phase-0 evolutionary model testbed-design and experimental results

NASA Technical Reports Server (NTRS)

Belvin, W. K.; Horta, Lucas G.; Elliott, K. B.

1991-01-01

A testbed for the development of Controls Structures Interaction (CSI) technology is described. The design philosophy, capabilities, and early experimental results are presented to introduce some of the ongoing CSI research at NASA-Langley. The testbed, referred to as the Phase 0 version of the CSI Evolutionary model (CEM), is the first stage of model complexity designed to show the benefits of CSI technology and to identify weaknesses in current capabilities. Early closed loop test results have shown non-model based controllers can provide an order of magnitude increase in damping in the first few flexible vibration modes. Model based controllers for higher performance will need to be robust to model uncertainty as verified by System ID tests. Data are presented that show finite element model predictions of frequency differ from those obtained from tests. Plans are also presented for evolution of the CEM to study integrated controller and structure design as well as multiple payload dynamics.

Full-Duplex Bidirectional Secure Communications Under Perfect and Distributionally Ambiguous Eavesdropper's CSI

NASA Astrophysics Data System (ADS)

Li, Qiang; Zhang, Ying; Lin, Jingran; Wu, Sissi Xiaoxiao

2017-09-01

Consider a full-duplex (FD) bidirectional secure communication system, where two communication nodes, named Alice and Bob, simultaneously transmit and receive confidential information from each other, and an eavesdropper, named Eve, overhears the transmissions. Our goal is to maximize the sum secrecy rate (SSR) of the bidirectional transmissions by optimizing the transmit covariance matrices at Alice and Bob. To tackle this SSR maximization (SSRM) problem, we develop an alternating difference-of-concave (ADC) programming approach to alternately optimize the transmit covariance matrices at Alice and Bob. We show that the ADC iteration has a semi-closed-form beamforming solution, and is guaranteed to converge to a stationary solution of the SSRM problem. Besides the SSRM design, this paper also deals with a robust SSRM transmit design under a moment-based random channel state information (CSI) model, where only some roughly estimated first and second-order statistics of Eve's CSI are available, but the exact distribution or other high-order statistics is not known. This moment-based error model is new and different from the widely used bounded-sphere error model and the Gaussian random error model. Under the consider CSI error model, the robust SSRM is formulated as an outage probability-constrained SSRM problem. By leveraging the Lagrangian duality theory and DC programming, a tractable safe solution to the robust SSRM problem is derived. The effectiveness and the robustness of the proposed designs are demonstrated through simulations.

Mechanism of Cd2+-coordination during Slow Inactivation in Potassium Channels

PubMed Central

Raghuraman, H.; Cordero-Morales, Julio F.; Jogini, Vishwanath; Pan, Albert C.; Kollewe, Astrid; Roux, Benoît; Perozo, Eduardo

2013-01-01

Summary In K+ channels, rearrangements of the pore outer-vestibule have been associated with C-type inactivation gating. Paradoxically, the crystal structure of Open/C-type inactivated KcsA suggest these movements to be modest in magnitude. Here, we show that under physiological conditions, the KcsA outer-vestibule undergoes relatively large dynamic rearrangements upon inactivation. External Cd2+ enhances the rate of C-type inactivation in an outer-vestibule cysteine mutant (Y82C) via metal-bridge formation. This effect is not present in a non-inactivating mutant (E71A/Y82C). Tandem dimer and tandem tetramer constructs of equivalent cysteine mutants in KcsA and Shaker K+ channels demonstrate that these Cd2+ metal bridges are formed only between adjacent subunits. This is well supported by molecular dynamics simulations. Based on the crystal structure of Cd2+-bound Y82C-KcsA in the closed state, together with EPR distance measurements in the KcsA outer-vestibule, we suggest that subunits must dynamically come in close proximity as the channels undergo inactivation. PMID:22771214

CSI Feedback Reduction for MIMO Interference Alignment

NASA Astrophysics Data System (ADS)

Rao, Xiongbin; Ruan, Liangzhong; Lau, Vincent K. N.

2013-09-01

Interference alignment (IA) is a linear precoding strategy that can achieve optimal capacity scaling at high SNR in interference networks. Most of the existing IA designs require full channel state information (CSI) at the transmitters, which induces a huge CSI signaling cost. Hence it is desirable to improve the feedback efficiency for IA and in this paper, we propose a novel IA scheme with a significantly reduced CSI feedback. To quantify the CSI feedback cost, we introduce a novel metric, namely the feedback dimension. This metric serves as a first-order measurement of CSI feedback overhead. Due to the partial CSI feedback constraint, conventional IA schemes can not be applied and hence, we develop a novel IA precoder / decorrelator design and establish new IA feasibility conditions. Via dynamic feedback profile design, the proposed IA scheme can also achieve a flexible tradeoff between the degree of freedom (DoF) requirements for data streams, the antenna resources and the CSI feedback cost. We show by analysis and simulations that the proposed scheme achieves substantial reductions of CSI feedback overhead under the same DoF requirement in MIMO interference networks.

Control-Structure-Interaction (CSI) technologies and trends to future NASA missions

NASA Technical Reports Server (NTRS)

1990-01-01

Control-structure-interaction (CSI) issues which are relevant for future NASA missions are reviewed. This goal was achieved by: (1) reviewing large space structures (LSS) technologies to provide a background and survey of the current state of the art (SOA); (2) analytically studying a focus mission to identify opportunities where CSI technology may be applied to enhance or enable future NASA spacecraft; and (3) expanding a portion of the focus mission, the large antenna, to provide in-depth trade studies, scaling laws, and methodologies which may be applied to other NASA missions. Several sections are presented. Section 1 defines CSI issues and presents an overview of the relevant modeling and control issues for LLS. Section 2 presents the results of the three phases of the CSI study. Section 2.1 gives the results of a CSI study conducted with the Geostationary Platform (Geoplat) as the focus mission. Section 2.2 contains an overview of the CSI control design methodology available in the technical community. Included is a survey of the CSI ground-based experiments which were conducted to verify theoretical performance predictions. Section 2.3 presents and demonstrates a new CSI scaling law methodology for assessing potential CSI with large antenna systems.

CSI computer system/remote interface unit acceptance test results

NASA Technical Reports Server (NTRS)

Sparks, Dean W., Jr.

1992-01-01

The validation tests conducted on the Control/Structures Interaction (CSI) Computer System (CCS)/Remote Interface Unit (RIU) is discussed. The CCS/RIU consists of a commercially available, Langley Research Center (LaRC) programmed, space flight qualified computer and a flight data acquisition and filtering computer, developed at LaRC. The tests were performed in the Space Structures Research Laboratory (SSRL) and included open loop excitation, closed loop control, safing, RIU digital filtering, and RIU stand alone testing with the CSI Evolutionary Model (CEM) Phase-0 testbed. The test results indicated that the CCS/RIU system is comparable to ground based systems in performing real-time control-structure experiments.

Molecular and kinetic determinants of local anaesthetic action on sodium channels.

PubMed

French, R J; Zamponi, G W; Sierralta, I E

1998-11-23

(1) Local anaesthetics (LA) rely for their clinical actions on state-dependent inhibition of voltage-dependent sodium channels. (2) Single, batrachoxin-modified sodium channels in planar lipid bilayers allow direct observation of drug-channel interactions. Two modes of inhibition of single-channel current are observed: fast block of the open channels and prolongation of a long-lived closed state, some of whose properties resemble those of the inactivated state of unmodified channels. (3) Analogues of different parts of the LA molecule separately mimic each blocking mode: amines--fast block, and water-soluble aromatics--closed state prolongation. (4) Interaction between a mu-conotoxin derivative and diethylammonium indicate an intrapore site of fast, open-state block. (5) Site-directed mutagenesis studies suggest that hydrophobic residues in transmembrane segment 6 of repeat domain 4 of sodium channels are critical for both LA binding and stabilization of the inactivated state.

Inactivation of A currents and A channels on rat nodose neurons in culture

PubMed Central

1989-01-01

Cultured sensory neurons from nodose ganglia were investigated with whole-cell patch-clamp techniques and single-channel recordings to characterize the A current. Membrane depolarization from -40 mV holding potential activated the delayed rectifier current (IK) at potentials positive to -30 mV; this current had a sigmoidal time course and showed little or no inactivation. In most neurons, the A current was completely inactivated at the -40 mV holding potential and required hyperpolarization to remove the inactivation; the A current was isolated by subtracting the IK evoked by depolarizations from -40 mV from the total outward current evoked by depolarizations from -90 mV. The decay of the A current on several neurons had complex kinetics and was fit by the sum of three exponentials whose time constants were 10- 40 ms, 100-350 ms, and 1-3 s. At the single-channel level we found that one class of channel underlies the A current. The conductance of A channels varied with the square root of the external K concentration: it was 22 pS when exposed to 5.4 mM K externally, the increased to 40 pS when exposed to 140 mM K externally. A channels activated rapidly upon depolarization and the latency to first opening decreased with depolarization. The open time distributions followed a single exponential and the mean open time increased with depolarization. A channels inactivate in three different modes: some A channels inactivated with little reopening and gave rise to ensemble averages that decayed in 10-40 ms; other A channels opened and closed three to four times before inactivating and gave rise to ensemble averages that decayed in 100-350 ms; still other A channels opened and closed several hundred times and required seconds to inactivate. Channels gating in all three modes contributed to the macroscopic A current from the whole cell, but their relative contribution differed among neurons. In addition, A channels could go directly from the closed, or resting, state to the inactivated state without opening, and the probability for channels inactivating in this way was greater at less depolarized voltages. In addition, a few A channels appeared to go reversibly from a mode where inactivation occurred rapidly to a slow mode of inactivation. PMID:2592953

Discovery of SiCSi in IRC +10216: A missing link between gas and dust carriers of Si–C bonds

PubMed Central

Cernicharo, J.; McCarthy, M. C.; Gottlieb, C. A.; Agúndez, M.; Velilla Prieto, L.; Baraban, J. H.; Changala, P. B.; Guélin, M.; Kahane, C.; Martin-Drumel, M. A.; Patel, N. A.; Reilly, N. J.; Stanton, J. F.; Quintana-Lacaci, G.; Thorwirth, S.; Young, K. H.

2015-01-01

We report the discovery in space of a disilicon species, SiCSi, from observations between 80 and 350 GHz with the IRAM10 30m radio telescope. Owing to the close coordination between laboratory experiments and astrophysics, 112 lines have now been detected in the carbon-rich star CW Leo. The derived frequencies yield improved rotational and centrifugal distortion constants up to sixth order. From the line profiles and interferometric maps with the Submillimeter Array11, the bulk of the SiCSi emission arises from a region of 6″ in radius. The derived abundance is comparable to that of SiC2. As expected from chemical equilibrium calculations, SiCSi and SiC2 are the most abundant species harboring a Si–C bond in the dust formation zone and certainly both play a key role in the formation of SiC dust grains. PMID:26722621

Spatially Common Sparsity Based Adaptive Channel Estimation and Feedback for FDD Massive MIMO

NASA Astrophysics Data System (ADS)

Gao, Zhen; Dai, Linglong; Wang, Zhaocheng; Chen, Sheng

2015-12-01

This paper proposes a spatially common sparsity based adaptive channel estimation and feedback scheme for frequency division duplex based massive multi-input multi-output (MIMO) systems, which adapts training overhead and pilot design to reliably estimate and feed back the downlink channel state information (CSI) with significantly reduced overhead. Specifically, a non-orthogonal downlink pilot design is first proposed, which is very different from standard orthogonal pilots. By exploiting the spatially common sparsity of massive MIMO channels, a compressive sensing (CS) based adaptive CSI acquisition scheme is proposed, where the consumed time slot overhead only adaptively depends on the sparsity level of the channels. Additionally, a distributed sparsity adaptive matching pursuit algorithm is proposed to jointly estimate the channels of multiple subcarriers. Furthermore, by exploiting the temporal channel correlation, a closed-loop channel tracking scheme is provided, which adaptively designs the non-orthogonal pilot according to the previous channel estimation to achieve an enhanced CSI acquisition. Finally, we generalize the results of the multiple-measurement-vectors case in CS and derive the Cramer-Rao lower bound of the proposed scheme, which enlightens us to design the non-orthogonal pilot signals for the improved performance. Simulation results demonstrate that the proposed scheme outperforms its counterparts, and it is capable of approaching the performance bound.

Effect of phenytoin on sodium conductances in rat hippocampal CA1 pyramidal neurons

PubMed Central

Zeng, Zhen; Hill-Yardin, Elisa L.; Williams, David; O'Brien, Terence; Serelis, Andris

2016-01-01

The antiepileptic drug phenytoin (PHT) is thought to reduce the excitability of neural tissue by stabilizing sodium channels (NaV) in inactivated states. It has been suggested the fast-inactivated state (IF) is the main target, although slow inactivation (IS) has also been implicated. Other studies on local anesthetics with similar effects on sodium channels have implicated the NaV voltage sensor interactions. In this study, we reexamined the effect of PHT in both equilibrium and dynamic transitions between fast and slower forms of inactivation in rat hippocampal CA1 pyramidal neurons. The effects of PHT were observed on fast and slow inactivation processes, as well as on another identified “intermediate” inactivation process. The effect of enzymatic removal of IF was also studied, as well as effects on the residual persistent sodium current (INaP). A computational model based on a gating charge interaction was derived that reproduced a range of PHT effects on NaV equilibrium and state transitions. No effect of PHT on IF was observed; rather, PHT appeared to facilitate the occupancy of other closed states, either through enhancement of slow inactivation or through formation of analogous drug-bound states. The overall significance of these observations is that our data are inconsistent with the commonly held view that the archetypal NaV channel inhibitor PHT stabilizes fast inactivation states, and we demonstrate that conventional slow activation “IS” and the more recently identified intermediate-duration inactivation process “II” are the primary functional targets of PHT. In addition, we show that the traditional explanatory frameworks based on the “modulated receptor hypothesis” can be substituted by simple, physiologically plausible interactions with voltage sensors. Additionally, INaP was not preferentially inhibited compared with peak INa at short latencies (50 ms) by PHT. PMID:27489371

Auxiliary KChIP4a Suppresses A-type K+ Current through Endoplasmic Reticulum (ER) Retention and Promoting Closed-state Inactivation of Kv4 Channels*

PubMed Central

Tang, Yi-Quan; Liang, Ping; Zhou, Jingheng; Lu, Yanxin; Lei, Lei; Bian, Xiling; Wang, KeWei

2013-01-01

In the brain and heart, auxiliary Kv channel-interacting proteins (KChIPs) co-assemble with pore-forming Kv4 α-subunits to form a native K+ channel complex and regulate the expression and gating properties of Kv4 currents. Among the KChIP1–4 members, KChIP4a exhibits a unique N terminus that is known to suppress Kv4 function, but the underlying mechanism of Kv4 inhibition remains unknown. Using a combination of confocal imaging, surface biotinylation, and electrophysiological recordings, we identified a novel endoplasmic reticulum (ER) retention motif, consisting of six hydrophobic and aliphatic residues, 12–17 (LIVIVL), within the KChIP4a N-terminal KID, that functions to reduce surface expression of Kv4-KChIP complexes. This ER retention capacity is transferable and depends on its flanking location. In addition, adjacent to the ER retention motif, the residues 19–21 (VKL motif) directly promote closed-state inactivation of Kv4.3, thus leading to an inhibition of channel current. Taken together, our findings demonstrate that KChIP4a suppresses A-type Kv4 current via ER retention and enhancement of Kv4 closed-state inactivation. PMID:23576435

Auxiliary KChIP4a suppresses A-type K+ current through endoplasmic reticulum (ER) retention and promoting closed-state inactivation of Kv4 channels.

PubMed

Tang, Yi-Quan; Liang, Ping; Zhou, Jingheng; Lu, Yanxin; Lei, Lei; Bian, Xiling; Wang, KeWei

2013-05-24

In the brain and heart, auxiliary Kv channel-interacting proteins (KChIPs) co-assemble with pore-forming Kv4 α-subunits to form a native K(+) channel complex and regulate the expression and gating properties of Kv4 currents. Among the KChIP1-4 members, KChIP4a exhibits a unique N terminus that is known to suppress Kv4 function, but the underlying mechanism of Kv4 inhibition remains unknown. Using a combination of confocal imaging, surface biotinylation, and electrophysiological recordings, we identified a novel endoplasmic reticulum (ER) retention motif, consisting of six hydrophobic and aliphatic residues, 12-17 (LIVIVL), within the KChIP4a N-terminal KID, that functions to reduce surface expression of Kv4-KChIP complexes. This ER retention capacity is transferable and depends on its flanking location. In addition, adjacent to the ER retention motif, the residues 19-21 (VKL motif) directly promote closed-state inactivation of Kv4.3, thus leading to an inhibition of channel current. Taken together, our findings demonstrate that KChIP4a suppresses A-type Kv4 current via ER retention and enhancement of Kv4 closed-state inactivation.

Derivation of Hodgkin-Huxley equations for a Na+ channel from a master equation for coupled activation and inactivation

NASA Astrophysics Data System (ADS)

Vaccaro, S. R.

2016-11-01

The Na+ current in nerve and muscle membranes may be described in terms of the activation variable m (t ) and the inactivation variable h (t ) , which are dependent on the transitions of S4 sensors of each of the Na+ channel domains DI to DIV. The time-dependence of the Na+ current and the rate equations satisfied by m (t ) and h (t ) may be derived from the solution to a master equation that describes the coupling between two or three activation sensors regulating the Na+ channel conductance and a two-stage inactivation process. If the inactivation rate from the closed or open states increases as the S4 sensors activate, a more general form of the Hodgkin-Huxley expression for the open-state probability may be derived where m (t ) is dependent on both activation and inactivation processes. The voltage dependence of the rate functions for inactivation and recovery from inactivation are consistent with the empirically determined expressions and exhibit saturation for both depolarized and hyperpolarized clamp potentials.

A synopsis of test results and knowledge gained from the Phase-0 CSI evolutionary model

NASA Technical Reports Server (NTRS)

Belvin, W. Keith; Elliott, Kenny B.; Horta, Lucas G.

1993-01-01

The Phase-0 CSI Evolutionary Model (CEM) is a testbed for the study of space platform global line-of-sight (LOS) pointing. Now that the tests have been completed, a summary of hardware and closed-loop test experiences is necessary to insure a timely dissemination of the knowledge gained. The testbed is described and modeling experiences are presented followed by a summary of the research performed by various investigators. Some early lessons on implementing the closed-loop controllers are described with particular emphasis on real-time computing requirements. A summary of closed-loop studies and a synopsis of test results are presented. Plans for evolving the CEM from phase 0 to phases 1 and 2 are also described. Subsequently, a summary of knowledge gained from the design and testing of the Phase-0 CEM is made.

DISCOVERY OF SiCSi IN IRC+10216: A MISSING LINK BETWEEN GAS AND DUST CARRIERS OF Si–C BONDS

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

Cernicharo, J.; Agúndez, M.; Prieto, L. Velilla

2015-06-10

We report the discovery in space of a disilicon species, SiCSi, from observations between 80 and 350 GHz with the IRAM 30 m radio telescope. Owing to the close coordination between laboratory experiments and astrophysics, 112 lines have now been detected in the carbon-rich star CW Leo. The derived frequencies yield improved rotational and centrifugal distortion constants up to sixth order. From the line profiles and interferometric maps with the Submillimeter Array, the bulk of the SiCSi emission arises from a region of 6″ in radius. The derived abundance is comparable to that of SiC{sub 2}. As expected from chemicalmore » equilibrium calculations, SiCSi and SiC{sub 2} are the most abundant species harboring a Si−C bond in the dust formation zone and certainly both play a key role in the formation of SiC dust grains.« less

Inducing circular RNA formation using the CRISPR endoribonuclease Csy4

PubMed Central

Borchardt, Erin K.; Meganck, Rita M.; Vincent, Heather A.; Ball, Christopher B.; Ramos, Silvia B.V.; Moorman, Nathaniel J.; Marzluff, William F.; Asokan, Aravind

2017-01-01

Circular RNAs (circRNAs) are highly stable, covalently closed RNAs that are regulated in a spatiotemporal manner and whose functions are largely unknown. These molecules have the potential to be incorporated into engineered systems with broad technological implications. Here we describe a switch for inducing back-splicing of an engineered circRNA that relies on the CRISPR endoribonuclease, Csy4, as an activator of circularization. The endoribonuclease activity and 3′ end-stabilizing properties of Csy4 are particularly suited for this task. Coexpression of Csy4 and the circRNA switch allows for the removal of downstream competitive splice sites and stabilization of the 5′ cleavage product. This subsequently results in back-splicing of the 5′ cleavage product into a circRNA that can translate a reporter protein from an internal ribosomal entry site (IRES). Our platform outlines a straightforward approach toward regulating splicing and could find potential applications in synthetic biology as well as in studying the properties of different circRNAs. PMID:28223408

Depolarized inactivation overcomes impaired activation to produce DRG neuron hyperexcitability in a Nav1.7 mutation in a patient with distal limb pain.

PubMed

Huang, Jianying; Yang, Yang; Dib-Hajj, Sulayman D; van Es, Michael; Zhao, Peng; Salomon, Jody; Drenth, Joost P H; Waxman, Stephen G

2014-09-10

Sodium channel Nav1.7, encoded by SCN9A, is expressed in DRG neurons and regulates their excitability. Genetic and functional studies have established a critical contribution of Nav1.7 to human pain disorders. We have now characterized a novel Nav1.7 mutation (R1279P) from a female human subject with distal limb pain, in which depolarized fast inactivation overrides impaired activation to produce hyperexcitability and spontaneous firing in DRG neurons. Whole-cell voltage-clamp recordings in human embryonic kidney (HEK) 293 cells demonstrated that R1279P significantly depolarizes steady-state fast-, slow-, and closed-state inactivation. It accelerates deactivation, decelerates inactivation, and facilitates repriming. The mutation increases ramp currents in response to slow depolarizations. Our voltage-clamp analysis showed that R1279P depolarizes channel activation, a change that was supported by our multistate structural modeling. Because this mutation confers both gain-of-function and loss-of-function attributes on the Nav1.7 channel, we tested the impact of R1279P expression on DRG neuron excitability. Current-clamp studies reveal that R1279P depolarizes resting membrane potential, decreases current threshold, and increases firing frequency of evoked action potentials within small DRG neurons. The populations of spontaneously firing and repetitively firing neurons were increased by expressing R1279P. These observations indicate that the dominant proexcitatory gating changes associated with this mutation, including depolarized steady-state fast-, slow-, and closed-state inactivation, faster repriming, and larger ramp currents, override the depolarizing shift of activation, to produce hyperexcitability and spontaneous firing of nociceptive neurons that underlie pain. Copyright © 2014 the authors 0270-6474/14/3412328-13$15.00/0.

Domain model for Ca2(+)-inactivation of Ca2+ channels at low channel density.

PubMed Central

Sherman, A; Keizer, J; Rinzel, J

1990-01-01

The "shell" model for Ca2(+)-inactivation of Ca2+ channels is based on the accumulation of Ca2+ in a macroscopic shell beneath the plasma membrane. The shell is filled by Ca2+ entering through open channels, with the elevated Ca2+ concentration inactivating both open and closed channels at a rate determined by how fast the shell is filled. In cells with low channel density, the high concentration Ca2+ "shell" degenerates into a collection of nonoverlapping "domains" localized near open channels. These domains form rapidly when channels open and disappear rapidly when channels close. We use this idea to develop a "domain" model for Ca2(+)-inactivation of Ca2+ channels. In this model the kinetics of formation of an inactivated state resulting from Ca2+ binding to open channels determines the inactivation rate, a mechanism identical with that which explains single-channel recordings on rabbit-mesenteric artery Ca2+ channels (Huang Y., J. M. Quayle, J. F. Worley, N. B. Standen, and M. T. Nelson. 1989. Biophys. J. 56:1023-1028). We show that the model correctly predicts five important features of the whole-cell Ca2(+)-inactivation for mouse pancreatic beta-cells (Plants, T. D. 1988. J. Physiol. 404:731-747) and that Ca2(+)-inactivation has only minor effects on the bursting electrical activity of these cells. PMID:2174274

Cellulose synthase interactive protein 1 (CSI1) mediates the intimate relationship between cellulose microfibrils and cortical microtubules.

PubMed

Lei, Lei; Li, Shundai; Gu, Ying

2012-07-01

Cellulose is synthesized at the plasma membrane by protein complexes known as cellulose synthase complexes (CSCs). The cellulose-microtubule alignment hypothesis states that there is a causal link between the orientation of cortical microtubules and orientation of nascent cellulose microfibrils. The mechanism behind the alignment hypothesis is largely unknown. CESA interactive protein 1 (CSI1) interacts with CSCs and potentially links CSCs to the cytoskeleton. CSI1 not only co-localizes with CSCs but also travels bi-directionally in a speed indistinguishable from CSCs. The linear trajectories of CSI1-RFP coincide with the underlying microtubules labeled by YFP-TUA5. In the absence of CSI1, both the distribution and the motility of CSCs are defective and the alignment of CSCs and microtubules is disrupted. These observations led to the hypothesis that CSI1 directly mediates the interaction between CSCs and microtubules. In support of this hypothesis, CSI1 binds to microtubules directly by an in vitro microtubule-binding assay. In addition to a role in serving as a messenger from microtubule to CSCs, CSI1 labels SmaCCs/MASCs, a compartment that has been proposed to be involved in CESA trafficking and/or delivery to the plasma membrane.

Cellulose synthase interactive protein 1 (CSI1) mediates the intimate relationship between cellulose microfibrils and cortical microtubules

PubMed Central

Lei, Lei; Li, Shundai; Gu, Ying

2012-01-01

Cellulose is synthesized at the plasma membrane by protein complexes known as cellulose synthase complexes (CSCs). The cellulose-microtubule alignment hypothesis states that there is a causal link between the orientation of cortical microtubules and orientation of nascent cellulose microfibrils. The mechanism behind the alignment hypothesis is largely unknown. CESA interactive protein 1 (CSI1) interacts with CSCs and potentially links CSCs to the cytoskeleton. CSI1 not only co-localizes with CSCs but also travels bi-directionally in a speed indistinguishable from CSCs. The linear trajectories of CSI1-RFP coincide with the underlying microtubules labeled by YFP-TUA5. In the absence of CSI1, both the distribution and the motility of CSCs are defective and the alignment of CSCs and microtubules is disrupted. These observations led to the hypothesis that CSI1 directly mediates the interaction between CSCs and microtubules. In support of this hypothesis, CSI1 binds to microtubules directly by an in vitro microtubule-binding assay. In addition to a role in serving as a messenger from microtubule to CSCs, CSI1 labels SmaCCs/MASCs, a compartment that has been proposed to be involved in CESA trafficking and/or delivery to the plasma membrane. PMID:22751327

Caring for the patients with cervical spine injuries: what have we learned?

PubMed

Ghafoor, Abid U; Martin, Timothy W; Gopalakrishnan, Senthil; Viswamitra, Sanjaya

2005-12-01

Anesthesiologists are often involved in the early management and resuscitation of patients who have sustained cervical spine injuries (CSIs). The most crucial step in managing a patient with suspected CSI is the prevention of further insult to the cervical spine (C-spine). In this review, important factors related to initial management, diagnosis, airway and anesthetic management of patients with CSI are presented. Medline search was performed to seek out the English-language literature using the following phrases and keywords: spine trauma; cervical spine; airway management after CSI. Cervical spine injury occurs in up to 3% to 6% of all patients with trauma. The initial management of a patient with potential spine injury requires a high degree of suspicion for CSI so that early stabilization of the spine can be used to prevent further neurological damage. Diagnostic radiology has a critical role to play; however, clinical evaluation is equally important in excluding CSI in a conscious and cooperative patient. Although in-line stabilization reduces the movement at C-spine, traction causes clinically significant distraction and should be avoided. A high level of suspicion and anticipation are the major components of decision making and management in a patient with CSI. Endotracheal intubation using the Bullard laryngoscope may have some advantages over other techniques as it causes less head and C-spine extension than the conventional laryngoscope, and this results in a better view. However, the current opinion is that oral intubation using a Macintosh blade after intravenous induction of anesthesia and muscle relaxation along with inline stabilization is the safest and quickest way to achieve intubation in a patient with suspected CSI. In summation caution, close care and maintenance of spinal immobilization are more important factors in limiting the risk of secondary neurological injury than any particular technique.

Inducing circular RNA formation using the CRISPR endoribonuclease Csy4.

PubMed

Borchardt, Erin K; Meganck, Rita M; Vincent, Heather A; Ball, Christopher B; Ramos, Silvia B V; Moorman, Nathaniel J; Marzluff, William F; Asokan, Aravind

2017-05-01

Circular RNAs (circRNAs) are highly stable, covalently closed RNAs that are regulated in a spatiotemporal manner and whose functions are largely unknown. These molecules have the potential to be incorporated into engineered systems with broad technological implications. Here we describe a switch for inducing back-splicing of an engineered circRNA that relies on the CRISPR endoribonuclease, Csy4, as an activator of circularization. The endoribonuclease activity and 3' end-stabilizing properties of Csy4 are particularly suited for this task. Coexpression of Csy4 and the circRNA switch allows for the removal of downstream competitive splice sites and stabilization of the 5' cleavage product. This subsequently results in back-splicing of the 5' cleavage product into a circRNA that can translate a reporter protein from an internal ribosomal entry site (IRES). Our platform outlines a straightforward approach toward regulating splicing and could find potential applications in synthetic biology as well as in studying the properties of different circRNAs. © 2017 Borchardt et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society.

Ternary Kv4.2 channels recapitulate voltage-dependent inactivation kinetics of A-type K+ channels in cerebellar granule neurons.

PubMed

Amarillo, Yimy; De Santiago-Castillo, Jose A; Dougherty, Kevin; Maffie, Jonathon; Kwon, Elaine; Covarrubias, Manuel; Rudy, Bernardo

2008-04-15

Kv4 channels mediate most of the somatodendritic subthreshold operating A-type current (I(SA)) in neurons. This current plays essential roles in the regulation of spike timing, repetitive firing, dendritic integration and plasticity. Neuronal Kv4 channels are thought to be ternary complexes of Kv4 pore-forming subunits and two types of accessory proteins, Kv channel interacting proteins (KChIPs) and the dipeptidyl-peptidase-like proteins (DPPLs) DPPX (DPP6) and DPP10. In heterologous cells, ternary Kv4 channels exhibit inactivation that slows down with increasing depolarization. Here, we compared the voltage dependence of the inactivation rate of channels expressed in heterologous mammalian cells by Kv4.2 proteins with that of channels containing Kv4.2 and KChIP1, Kv4.2 and DPPX-S, or Kv4.2, KChIP1 and DPPX-S, and found that the relation between inactivation rate and membrane potential is distinct for these four conditions. Moreover, recordings from native neurons showed that the inactivation kinetics of the I(SA) in cerebellar granule neurons has voltage dependence that is remarkably similar to that of ternary Kv4 channels containing KChIP1 and DPPX-S proteins in heterologous cells. The fact that this complex and unique behaviour (among A-type K(+) currents) is observed in both the native current and the current expressed in heterologous cells by the ternary complex containing Kv4, DPPX and KChIP proteins supports the hypothesis that somatically recorded native Kv4 channels in neurons include both types of accessory protein. Furthermore, quantitative global kinetic modelling showed that preferential closed-state inactivation and a weakly voltage-dependent opening step can explain the slowing of the inactivation rate with increasing depolarization. Therefore, it is likely that preferential closed-state inactivation is the physiological mechanism that regulates the activity of both ternary Kv4 channel complexes and native I(SA)-mediating channels.

Molecular determinants of voltage-dependent gating and binding of pore-blocking drugs in transmembrane segment IIIS6 of the Na(+) channel alpha subunit.

PubMed

Yarov-Yarovoy, V; Brown, J; Sharp, E M; Clare, J J; Scheuer, T; Catterall, W A

2001-01-05

Mutations of amino acid residues in the inner two-thirds of the S6 segment in domain III of the rat brain type IIA Na(+) channel (G1460A to I1473A) caused periodic positive and negative shifts in the voltage dependence of activation, consistent with an alpha-helix having one face on which mutations to alanine oppose activation. Mutations in the outer one-third of the IIIS6 segment all favored activation. Mutations in the inner half of IIIS6 had strong effects on the voltage dependence of inactivation from closed states without effect on open-state inactivation. Only three mutations had strong effects on block by local anesthetics and anticonvulsants. Mutations L1465A and I1469A decreased affinity of inactivated Na(+) channels up to 8-fold for the anticonvulsant lamotrigine and its congeners 227c89, 4030w92, and 619c89 as well as for the local anesthetic etidocaine. N1466A decreased affinity of inactivated Na(+) channels for the anticonvulsant 4030w92 and etidocaine by 3- and 8-fold, respectively, but had no effect on affinity of the other tested compounds. Leu-1465, Asn-1466, and Ile-1469 are located on one side of the IIIS6 helix, and mutation of each caused a positive shift in the voltage dependence of activation. Evidently, these amino acid residues face the lumen of the pore, contribute to formation of the high-affinity receptor site for pore-blocking drugs, and are involved in voltage-dependent activation and coupling to closed-state inactivation.

Molecular physiology and modulation of somatodendritic A-type potassium channels.

PubMed

Jerng, Henry H; Pfaffinger, Paul J; Covarrubias, Manuel

2004-12-01

The somatodendritic subthreshold A-type K+ current (ISA) in nerve cells is a critical component of the ensemble of voltage-gated ionic currents that determine somatodendritic signal integration. The underlying K+ channel belongs to the Shal subfamily of voltage-gated K+ channels. Most Shal channels across the animal kingdom share a high degree of structural conservation, operate in the subthreshold range of membrane potentials, and exhibit relatively fast inactivation and recovery from inactivation. Mammalian Shal K+ channels (Kv4) undergo preferential closed-state inactivation with features that are generally inconsistent with the classical mechanisms of inactivation typical of Shaker K+ channels. Here, we review (1) the physiological and genetic properties of ISA, 2 the molecular mechanisms of Kv4 inactivation and its remodeling by a family of soluble calcium-binding proteins (KChIPs) and a membrane-bound dipeptidase-like protein (DPPX), and (3) the modulation of Kv4 channels by protein phosphorylation.

Lack of voltage-dependent calcium channel opening during the calcium influx induced by progesterone in human sperm. Effect of calcium channel deactivation and inactivation.

PubMed

Guzmán-Grenfell, Alberto Martín; González-Martínez, Marco T

2004-01-01

Progesterone induces calcium influx and acrosomal exocytosis in human sperm. Pharmacologic evidence suggests that voltage-dependent calcium channels (VDCCs) are involved. In this study, membrane potential (Vm) and intracellular calcium concentration ([Ca(2+)](i)) were monitored simultaneously to assess the effect of VDCC gating on the calcium influx triggered by progesterone. Holding the Vm to values that maintained VDCCs in a deactivated (-71 mV) closed state inhibited the calcium influx induced by progesterone by approximately 40%. At this Vm, the acrosomal reaction induced by progesterone, but not by A23187, was inhibited. However, when the Vm was held at -15 mV (which maintains VDCCs in an inactivated closed state), the progesterone-induced calcium influx was stimulated. Furthermore, the progesterone and voltage-dependent calcium influxes were additive. These findings indicate that progesterone does not produce VDCC gating in human sperm.

FleCSPH notes

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

Lim, Hyun; Loiseau, Julien

FleCSI is a compile-time con gurable framework designed to support multi-physics application development. As such, FleCSI provides a very general set of infrastructure design patterns that can be specialized and extended to suit the needs of a broad variety of solver and data requirements. FleCSI currently supports multi-dimensional mesh topology, geometry, and adjacency information, as well as n-dimensional hashed-tree data structures, graph partitioning interfaces, and dependency closures. FleCSI introduces a functional programming model with control, execution, and data abstractions that are consistent both with MPI and with state-of-the-art, task-based runtimes such as Legion and Charm++. The abstraction layer insulates developersmore » from the underlying runtime, while allowing support for multiple runtime systems including conventional models like asynchronous MPI. The intent is to provide developers with a concrete set of user-friendly programming tools that can be used now, while allowing exibility in choosing runtime implementations and optimization that can be applied to future architectures and runtimes. FleCSI's control and execution models provide formal nomenclature for describing poorly understood concepts such as kernels and tasks. FleCSI's data model provides a low-buy-in approach that makes it an attractive option for many application projects, as developers are not locked into particular layouts or data structure representations. FleCSI currently provides a parallel but not distributed implementation of Binary, Quad and Oct-tree topology. This implementation is base on space lling curves domain decomposition, the Morton order. The current FleCSI version requires the implementation of a driver and a specialization driver. The role of the specialization driver is to provide the data distribution. This feature is not complete in FleCSI code and we provide it. The next step will be to incorporate it directly from FleCSPH to FleCSI as we reach a good level of performance. Then the driver represent the general execution of the resolution without worrying of the data locality and communications. As FleCSI is an On-Development code the structure may change in the future and we keep track of these changes in FleCSPH.« less

Evaluation of the relevance of the glassy state as stability criterion for freeze-dried bacteria by application of the Arrhenius and WLF model.

PubMed

Aschenbrenner, Mathias; Kulozik, Ulrich; Foerst, Petra

2012-12-01

The aim of this work was to describe the temperature dependence of microbial inactivation for several storage conditions and protective systems (lactose, trehalose and dextran) in relation to the physical state of the sample, i.e. the glassy or non-glassy state. The resulting inactivation rates k were described by applying two models, Arrhenius and Williams-Landel-Ferry (WLF), in order to evaluate the relevance of diffusional limitation as a protective mechanism. The application of the Arrhenius model revealed a significant decrease in activation energy E(a) for storage conditions close to T(g). This finding is an indication that the protective effect of a surrounding glassy matrix can, at least, partly be ascribed to its inherent restricted diffusion and mobility. The application of the WLF model revealed that the temperature dependence of microbial inactivation above T(g) is significantly weaker than predicted by the universal coefficients. Thus, it can be concluded that microbial inactivation is not directly linked with the mechanical relaxation behavior of the surrounding matrix as it was reported for viscosity and crystallization phenomena in case of disaccharide systems. Copyright © 2012. Published by Elsevier Inc.

Inhibition of cardiac sodium currents by toluene exposure

PubMed Central

Cruz, Silvia L; Orta-Salazar, Gerardo; Gauthereau, Marcia Y; Millan-Perez Peña, Lourdes; Salinas-Stefanón, Eduardo M

2003-01-01

Toluene is an industrial solvent widely used as a drug of abuse, which can produce sudden sniffing death due to cardiac arrhythmias. In this paper, we tested the hypothesis that toluene inhibits cardiac sodium channels in Xenopus laevis oocytes transfected with Nav1.5 cDNA and in isolated rat ventricular myocytes. In oocytes, toluene inhibited sodium currents (INa+) in a concentration-dependent manner, with an IC50 of 274 μM (confidence limits: 141–407μM). The inhibition was complete, voltage-independent, and slowly reversible. Toluene had no effect on: (i) the shape of the I–V curves; (ii) the reversal potential of Na+; and (iii) the steady-state inactivation. The slow recovery time constant from inactivation of INa+ decreased with toluene exposure, while the fast recovery time constant remained unchanged. Block of INa+ by toluene was use- and frequency-dependent. In rat cardiac myocytes, 300 μM toluene inhibited the sodium current (INa+) by 62%; this inhibition was voltage independent. These results suggest that toluene binds to cardiac Na+ channels in the open state and unbinds either when channels move between inactivated states or from an inactivated to a closed state. The use- and frequency-dependent block of INa+ by toluene might be responsible, at least in part, for its arrhythmogenic effect. PMID:14534149

Optimal Power Allocation for CC-HARQ-based Cognitive Radio with Statistical CSI in Nakagami Slow Fading Channels

NASA Astrophysics Data System (ADS)

Xu, Ding; Li, Qun

2017-01-01

This paper addresses the power allocation problem for cognitive radio (CR) based on hybrid-automatic-repeat-request (HARQ) with chase combining (CC) in Nakagamimslow fading channels. We assume that, instead of the perfect instantaneous channel state information (CSI), only the statistical CSI is available at the secondary user (SU) transmitter. The aim is to minimize the SU outage probability under the primary user (PU) interference outage constraint. Using the Lagrange multiplier method, an iterative and recursive algorithm is derived to obtain the optimal power allocation for each transmission round. Extensive numerical results are presented to illustrate the performance of the proposed algorithm.

Spin Seebeck effect and thermal colossal magnetoresistance in Christmas-tree silicene nanoribbons

NASA Astrophysics Data System (ADS)

Gao, Xiu-Jin; Zhao, Peng; Chen, Gang

2018-05-01

Based on the density functional theory and nonequilibrium Green's function method, we investigate the electronic structures and thermal spin transport properties of Christmas-tree silicene nanoribbons (CSiNRs). The results show that CSiNRs have ferromagnetic ground state with high Curie temperature far above the room temperature. Obvious spin Seebeck effect with spin-up and spin-down currents flowing in opposite directions by a temperature gradient can be observed in these systems. Furthermore, a thermal colossal magnetoresistance up to 109% can be realized by tuning the external magnetic field. The results show that CSiNRs hold great potential in designing spin caloritronic devices.

Langley's CSI evolutionary model: Phase O

NASA Technical Reports Server (NTRS)

Belvin, W. Keith; Elliott, Kenny B.; Horta, Lucas G.; Bailey, Jim P.; Bruner, Anne M.; Sulla, Jeffrey L.; Won, John; Ugoletti, Roberto M.

1991-01-01

A testbed for the development of Controls Structures Interaction (CSI) technology to improve space science platform pointing is described. The evolutionary nature of the testbed will permit the study of global line-of-sight pointing in phases 0 and 1, whereas, multipayload pointing systems will be studied beginning with phase 2. The design, capabilities, and typical dynamic behavior of the phase 0 version of the CSI evolutionary model (CEM) is documented for investigator both internal and external to NASA. The model description includes line-of-sight pointing measurement, testbed structure, actuators, sensors, and real time computers, as well as finite element and state space models of major components.

Instrumentation for Non-Invasive Assessment of Cardiovascular Regulation

NASA Technical Reports Server (NTRS)

Cohen, Richard J.

1999-01-01

It is critically important to be able to assess alterations in cardiovascular regulation during and after space flight. We propose to develop an instrument for the non-invasive assessment of such alterations that can be used on the ground and potentially during space flight. This instrumentation would be used by the Cardiovascular Alterations Team at multiple sites for the study of the effects of space flight on the cardiovascular system and the evaluation of countermeasures. In particular, the Cardiovascular Alterations Team will use this instrumentation in conjunction with ground-based human bed-rest studies and during application of acute stresses e.g., tilt, lower body negative pressure, and exercise. In future studies, the Cardiovascular Alterations Team anticipates using this instrumentation to study astronauts before and after space flight and ultimately, during space flight. The instrumentation may also be used by the Bone Demineralization/Calcium Metabolism Team, the Neurovestibular Team and the Human Performance Factors, Sleep and Chronobiology Team to measure changes in autonomic nervous function. The instrumentation will be based on a powerful new technology - cardiovascular system identification (CSI) - which has been developed in our laboratory. CSI provides a non-invasive approach for the study of alterations in cardiovascular regulation. This approach involves the analysis of second-to-second fluctuations in physiologic signals such as heart rate and non-invasively measured arterial blood pressure in order to characterize quantitatively the physiologic mechanisms responsible for the couplings between these signals. Through the characterization of multiple physiologic mechanisms, CSI provides a closed-loop model of the cardiovascular regulatory state in an individual subject.

Monitoring the Recovery of c-Si Modules from Potential-Induced Degradation Using Suns-Voc Curves

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

Wilterdink, Harrison; Sinton, Ronald; Hacke, Peter

2016-11-21

Potential-induced degradation (PID) has recently been shown as an important failure mode in c-Si modules. We demonstrate the utility of Suns-Voc analysis for measuring shunt effects caused by PID at the module level. Our results show module shunt resistance increasing in step with module power during recovery from the degraded state.

Using lidocaine and benzocaine to link sodium channel molecular conformations to state-dependent antiarrhythmic drug affinity.

PubMed

Hanck, Dorothy A; Nikitina, Elena; McNulty, Megan M; Fozzard, Harry A; Lipkind, Gregory M; Sheets, Michael F

2009-08-28

Lidocaine and other antiarrhythmic drugs bind in the inner pore of voltage-gated Na channels and affect gating use-dependently. A phenylalanine in domain IV, S6 (Phe1759 in Na(V)1.5), modeled to face the inner pore just below the selectivity filter, is critical in use-dependent drug block. Measurement of gating currents and concentration-dependent availability curves to determine the role of Phe1759 in coupling of drug binding to the gating changes. The measurements showed that replacement of Phe1759 with a nonaromatic residue permits clear separation of action of lidocaine and benzocaine into 2 components that can be related to channel conformations. One component represents the drug acting as a voltage-independent, low-affinity blocker of closed channels (designated as lipophilic block), and the second represents high-affinity, voltage-dependent block of open/inactivated channels linked to stabilization of the S4s in domains III and IV (designated as voltage-sensor inhibition) by Phe1759. A homology model for how lidocaine and benzocaine bind in the closed and open/inactivated channel conformation is proposed. These 2 components, lipophilic block and voltage-sensor inhibition, can explain the differences in estimates between tonic and open-state/inactivated-state affinities, and they identify how differences in affinity for the 2 binding conformations can control use-dependence, the hallmark of successful antiarrhythmic drugs.

Contrast source inversion (CSI) method to cross-hole radio-imaging (RIM) data - Part 2: A complex synthetic example and a case study

NASA Astrophysics Data System (ADS)

Li, Yongxing; Smith, Richard S.

2018-03-01

We present two examples of using the contrast source inversion (CSI) method to invert synthetic radio-imaging (RIM) data and field data. The synthetic model has two isolated conductors (one perfect conductor and one moderate conductor) embedded in a layered background. After inversion, we can identify the two conductors on the inverted image. The shape of the perfect conductor is better resolved than the shape of the moderate conductor. The inverted conductivity values of the two conductors are approximately the same, which demonstrates that the conductivity values cannot be correctly interpreted from the CSI results. The boundaries and the tilts of the upper and the lower conductive layers on the background can also be inferred from the results, but the centre parts of conductive layers in the inversion results are more conductive than the parts close to the boreholes. We used the straight-ray tomographic imaging method and the CSI method to invert the RIM field data collected using the FARA system between two boreholes in a mining area in Sudbury, Canada. The RIM data include the amplitude and the phase data collected using three frequencies: 312.5 kHz, 625 kHz and 1250 kHz. The data close to the ground surface have high amplitude values and complicated phase fluctuations, which are inferred to be contaminated by the reflected or refracted electromagnetic (EM) fields from the ground surface, and are removed for all frequencies. Higher-frequency EM waves attenuate more quickly in the subsurface environment, and the locations where the measurements are dominated by noise are also removed. When the data are interpreted with the straight-ray method, the images differ substantially for different frequencies. In addition, there are some unexpected features in the images, which are difficult to interpret. Compared with the straight-ray imaging results, the inversion results with the CSI method are more consistent for different frequencies. On the basis of what we learnt from the synthetic study, we interpret that there is one resistive layer across the middle of the borehole plane and two more conductive areas above and below this layer. Though there are some limitations in the study, such as large transmitter steps and the precise amplitudes and dipole moments being unknown, we conclude that the CSI method provides more interpretable images compared with the straight-ray method.

Domain IV voltage-sensor movement is both sufficient and rate limiting for fast inactivation in sodium channels.

PubMed

Capes, Deborah L; Goldschen-Ohm, Marcel P; Arcisio-Miranda, Manoel; Bezanilla, Francisco; Chanda, Baron

2013-08-01

Voltage-gated sodium channels are critical for the generation and propagation of electrical signals in most excitable cells. Activation of Na(+) channels initiates an action potential, and fast inactivation facilitates repolarization of the membrane by the outward K(+) current. Fast inactivation is also the main determinant of the refractory period between successive electrical impulses. Although the voltage sensor of domain IV (DIV) has been implicated in fast inactivation, it remains unclear whether the activation of DIV alone is sufficient for fast inactivation to occur. Here, we functionally neutralize each specific voltage sensor by mutating several critical arginines in the S4 segment to glutamines. We assess the individual role of each voltage-sensing domain in the voltage dependence and kinetics of fast inactivation upon its specific inhibition. We show that movement of the DIV voltage sensor is the rate-limiting step for both development and recovery from fast inactivation. Our data suggest that activation of the DIV voltage sensor alone is sufficient for fast inactivation to occur, and that activation of DIV before channel opening is the molecular mechanism for closed-state inactivation. We propose a kinetic model of sodium channel gating that can account for our major findings over a wide voltage range by postulating that DIV movement is both necessary and sufficient for fast inactivation.

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

Bergen, Ben; Moss, Nicholas; Charest, Marc Robert Joseph

FleCSI is a compile-time configurable framework designed to support multi-physics application development. As such, FleCSI attempts to provide a very general set of infrastructure design patterns that can be specialized and extended to suit the needs of a broad variety of solver and data requirements. Current support includes multi-dimensional mesh topology, mesh geometry, and mesh adjacency information, n-dimensional hashed-tree data structures, graph partitioning interfaces, and dependency closures. FleCSI also introduces a functional programming model with control, execution, and data abstractions that are consistent with both MPI and state-of-the-art task-based runtimes such as Legion and Charm++. The FleCSI abstraction layer providesmore » the developer with insulation from the underlying runtime, while allowing support for multiple runtime systems, including conventional models like asynchronous MPI. The intent is to give developers a concrete set of user-friendly programming tools that can be used now, while allowing flexibility in choosing runtime implementations and optimizations that can be applied to architectures and runtimes that arise in the future. The control and execution models in FleCSI also provide formal nomenclature for describing poorly understood concepts like kernels and tasks.« less

Coupling of activation and inactivation gate in a K+-channel: potassium and ligand sensitivity

PubMed Central

Ader, Christian; Schneider, Robert; Hornig, Sönke; Velisetty, Phanindra; Vardanyan, Vitya; Giller, Karin; Ohmert, Iris; Becker, Stefan; Pongs, Olaf; Baldus, Marc

2009-01-01

Potassium (K+)-channel gating is choreographed by a complex interplay between external stimuli, K+ concentration and lipidic environment. We combined solid-state NMR and electrophysiological experiments on a chimeric KcsA–Kv1.3 channel to delineate K+, pH and blocker effects on channel structure and function in a membrane setting. Our data show that pH-induced activation is correlated with protonation of glutamate residues at or near the activation gate. Moreover, K+ and channel blockers distinctly affect the open probability of both the inactivation gate comprising the selectivity filter of the channel and the activation gate. The results indicate that the two gates are coupled and that effects of the permeant K+ ion on the inactivation gate modulate activation-gate opening. Our data suggest a mechanism for controlling coordinated and sequential opening and closing of activation and inactivation gates in the K+-channel pore. PMID:19661921

Removal of inactivation causes time-invariant sodium current decays

PubMed Central

1988-01-01

The kinetic properties of the closing of Na channels were studied in frog skeletal muscle to obtain information about the dependence of channel closing on the past history of the channel. Channel closing was studied in normal and modified channels. Chloramine-T was used to modify the channels so that inactivation was virtually removed. A series of depolarizing prepulse potentials was used to activate Na channels, and a -140-mV postpulse was used to monitor the closing of the channels. Unmodified channels decay via a biexponential process with time constants of 72 and 534 microseconds at 12 degrees C. The observed time constants do not depend upon the potential used to activate the channels. The contribution of the slow component to the total decay increases as the activating prepulse is lengthened. After inactivation is removed, the biexponential character of the decay is retained, with no change in the magnitude of the time constants. However, increases in the duration of the activating prepulse over the range where the current is maximal 1-75 ms) produce identical biexponential decays. The presence of biexponential decays suggests that either two subtypes of Na channels are found in muscle, or Na channels can exist in one of two equally conductive states. The time- invariant decays observed suggest that channel closure does not depend upon their past history. PMID:2852208

Growth of single crystal silicon carbide by halide chemical vapor deposition

NASA Astrophysics Data System (ADS)

Fanton, Mark A.

The goal of this thesis is to understand relationships between the major process variables and the growth rate, doping, and defect density of SiC grown by halide chemical vapor deposition (HCVD). Specifically this work addresses the maximum C/Si ratios that can be utilized for single crystal SiC growth by providing a thermodynamic model for determining the boundary between single crystal growth and SiC+C mixed phase growth in the Si-C-Cl-H system. SiC epitaxial layers ranging from 50--200microm thick were grown at temperatures near 2000°C on 6H and 4H-SiC substrates at rates up to 250microm/hr. Experimental trends in the growth rate as a function of precursor flow rates and temperature closely match those expected from thermodynamic equilibrium in a closed system. The equilibrium model can be used to predict the trends in growth rate with the changes in precursor flow rates as well as the boundary between deposition of pure SiC and deposition of a mixture of SiC and C. Calculation of the boundary position in terms of the SiCl 4 and CH4 concentrations provides an upper limit on the C/Si ratio that can be achieved for any given set of crystal growth conditions. The model can be adjusted for changes in temperature, pressure, and chlorine concentration as well. The boundary between phase pure and mixed phase growth was experimentally shown to be very abrupt, thereby providing a well defined window for Si-rich and C-rich growth conditions. Growth of SiC epitaxial layers by HCVD under both Si-rich and C-rich conditions generally yielded the same trends in dopant incorporation as those observed in conventional silane-based CVD processes. Nitrogen incorporation was highest on the C-face of 4H-SiC substrates but could be reduced to concentrations as low as 1x1015 atoms/cm3 at C/Si ratios greater than 1. Residual B concentrations were slightly higher for epitaxial layers grown on the Si-face of substrates. However, changes in the C/Si ratio had no effect on B incorporation at concentrations on the order of 1x10 15 atoms/cm3. No significant trends in structural quality or defect density were evident as the C/Si ratio was varied from 0.72 to 1.81. Structural quality and defect density were more closely related to substrate off-cut and polarity. The highest quality crystals were grown on the C-face of 4° off-axis substrates as measured by HRXRD rocking curves. Growth on on-axis substrates was most successful on the C-face, although the x-ray rocking curves were nearly twice as wide as those on off-axis substrates. Etch pit densities obtained by KOH etching layers grown on Si-face substrates were closely related to the defect density of the substrate not the C/Si ratio. Thick p-type layers with B or Al dopant concentrations on the order of 1019 atoms/cm3 were readily achieved with the HCVD process. Trimethylaluminum and BCl3 were successfully employed as dopant sources. Aluminum incorporation was sensitive to both the substrate surface polarity and the C/Si ratio employed for growth. Dopant concentrations were maximized under C-rich growth conditions on the Si-face of SiC substrates. Boron incorporation was insensitive to both the surface polarity of the substrate and the C/Si used for layer growth even though B appears to favor incorporation on Si lattice sites. Boron acceptors in HCVD grown SiC are not passivated by H to any significant extent based on a comparison of net acceptor concentrations and B doping concentrations. In addition, the lattice parameters epitaxial layers doped with B at concentrations on the order of 1019 atoms/cm3 showed no change as a function of B concentration. This was in contrast to the lattice parameter decrease as expected from a comparison between the size of the Si and B atoms. The HCVD process has demonstrated an order of magnitude higher growth rates than conventional SiC CVD and while providing control over the C/Si ratio. This allows the user to directly influence dopant incorporation and growth morphology. However, this control should also permit several other material properties to be tailored. (Abstract shortened by UMI.)

Proton Beam Craniospinal Irradiation Reduces Acute Toxicity for Adults With Medulloblastoma

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

Brown, Aaron P.; Barney, Christian L.; Grosshans, David R.

2013-06-01

Purpose: Efficacy and acute toxicity of proton craniospinal irradiation (p-CSI) were compared with conventional photon CSI (x-CSI) for adults with medulloblastoma. Methods and Materials: Forty adult medulloblastoma patients treated with x-CSI (n=21) or p-CSI (n=19) at the University of Texas MD Anderson Cancer Center from 2003 to 2011 were retrospectively reviewed. Median CSI and total doses were 30.6 and 54 Gy, respectively. The median follow-up was 57 months (range 4-103) for x-CSI patients and 26 months (range 11-63) for p-CSI. Results: p-CSI patients lost less weight than x-CSI patients (1.2% vs 5.8%; P=.004), and less p-CSI patients had >5% weightmore » loss compared with x-CSI (16% vs 64%; P=.004). p-CSI patients experienced less grade 2 nausea and vomiting compared with x-CSI (26% vs 71%; P=.004). Patients treated with x-CSI were more likely to have medical management of esophagitis than p-CSI patients (57% vs 5%, P<.001). p-CSI patients had a smaller reduction in peripheral white blood cells, hemoglobin, and platelets compared with x-CSI (white blood cells 46% vs 55%, P=.04; hemoglobin 88% vs 97%, P=.009; platelets 48% vs 65%, P=.05). Mean vertebral doses were significantly associated with reductions in blood counts. Conclusions: This report is the first analysis of clinical outcomes for adult medulloblastoma patients treated with p-CSI. Patients treated with p-CSI experienced less treatment-related morbidity including fewer acute gastrointestinal and hematologic toxicities.« less

Cardiovascular Deconditioning in Humans: Alteration in Cardiovascular Regulation and Function During Simulated Microgravity

NASA Technical Reports Server (NTRS)

Cohen, Richard

1999-01-01

Alterations in cardiovascular regulation and function that occur during and after space flight have been reported. These alterations are manifested, for example, by reduced orthostatic tolerance upon reentry to the earth's gravity from space. However, the precise physiologic mechanisms responsible for these alterations remain to be fully elucidated. Perhaps, as a result, effective countermeasures have yet to be developed. In this project we apply a powerful, new method - cardiovascular system identification (CSI) - for the study of the effects of space flight on the cardiovascular system so that effective countermeasures can be developed. CSI involves the mathematical analysis of second-to-second fluctuations in non-invasively measured heart rate, arterial blood pressure (ABP), and instantaneous lung volume (ILV - respiratory activity) in order to characterize quantitatively the physiologic mechanisms responsible for the couplings between these signals. Through the characterization of all the physiologic mechanisms coupling these signals, CSI provides a model of the closed-loop cardiovascular regulatory state in an individual subject. The model includes quantitative descriptions of the heart rate baroreflex, autonomic function, as well as other important physiologic mechanisms. We are in the process of incorporating beat-to-beat fluctuations of stroke volume into the CSI technique in order to quantify additional physiologic mechanisms such as those involved in control of peripheral vascular resistance and alterations in cardiac contractility. We apply CSI in conjunction with the two general protocols of the Human Studies Core project. The first protocol involves ground-based, human head down tilt bed rest to simulate microgravity and acute stressors - upright tilt, standing and bicycle exercise - to provide orthostatic and exercise challenges. The second protocol is intended to be the same as the first but with the addition of sleep deprivation to determine whether this contributes to cardiovascular alterations. In these studies, we focus on the basic physiologic mechanisms responsible for the alterations in cardiovascular regulation and function during the simulated microgravity in order to formulate hypotheses regarding what countermeasures are likely to be most effective. Compared to our original proposal, the protocol we are using has been slightly modified to lengthen the bed rest period to 16 days and streamline the data collection. These modifications provide us data on a longer bed rest period and have enabled us to increase our subject throughput. Based on review of our preliminary data we have decided to test a countermeasure which is applied the very end of the bed rest period. We will use the same bed rest protocol to test this countermeasure. We anticipate completing the baseline data collection in our first protocol plus testing of the countermeasure in an additional eight subjects, at which time we plan to initiate the second protocol which includes sleep deprivation. In future studies, we plan to apply CSI to test other potential countermeasures in conjunction with the same bed rest, sleep deprivation and acute stressor models. We also anticipate applying CSI for studying astronauts before and after space flight and ultimately, during space flight. The application of CSI is providing information relevant to the development and evaluation of effective countermeasures allowing humans to adapt appropriately upon re-exposure to a gravity field, and to live and work for longer periods of time in microgravity.

Nickel Silicide Metallization for Passivated Tunneling Contacts for Silicon Solar Cells

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

Marshall, Alexander; Florent, Karine; Tapriya, Astha

Passivated tunneling contacts offer promise for applications in Interdigitated Back Passivated Contact (IBPC) high efficiency silicon solar cells. Metallization of these contacts remains a key research topic. This paper investigates NiSi/poly-Si/SiO2/c-Si passivated contacts using photoluminescence and contact resistivity measurements. An amorphous Si interlayer between the NiSi and poly-Si is observed to improve passivation, decreasing recombination. The overall recombination loss has a linear trend with the NiSi thickness. Implied Voc values close to 700 mV and contact resistivities below 10 mohm-cm2 have been achieved in NiSi/poly-Si:P/SiO2/c-Si contacts.

Using Lidocaine and Benzocaine to Link Sodium Channel Molecular Conformations to State-Dependent Antiarrhythmic Drug Affinity

PubMed Central

Hanck, Dorothy A.; Nikitina, Elena; McNulty, Megan M.; Fozzard, Harry A.; Lipkind, Gregory M.; Sheets, Michael F.

2009-01-01

Rationale Lidocaine and other antiarrhythmic drugs bind in the inner pore of voltage-gated Na channels and affect gating use-dependently. A phenylalanine in domain IV, S6 (Phe1759 in NaV1.5), modeled to face the inner pore just below the selectivity filter, is critical in use-dependent drug block. Objective Measurement of gating currents and concentration-dependent availability curves to determine the role of Phe1759 in coupling of drug binding to the gating changes. Methods & Results The measurements showed that replacement of Phe1759 with a non-aromatic residue permits clear separation of action of lidocaine and benzocaine into two components that can be related to channel conformations. One component represents the drug acting as a voltage-independent, low-affinity blocker of closed channels (designated as lipophilic block), and the second represents high-affinity, voltage-dependent block of open/inactivated channels linked to stabilization of the S4's in domains III and IV (designated as voltage-sensor inhibition) by Phe1759. A homology model for how lidocaine and benzocaine bind in the closed and open/inactivated channel conformation is proposed. Conclusions These two components, lipophilic block and voltage-sensor inhibition, can explain the differences in estimates between tonic and open-state/inactivated-state affinities, and they identify how differences in affinity for the two binding conformations can control use-dependence, the hallmark of successful antiarrhythmic drugs. PMID:19661462

Adaptive transmission based on multi-relay selection and rate-compatible LDPC codes

NASA Astrophysics Data System (ADS)

Su, Hualing; He, Yucheng; Zhou, Lin

2017-08-01

In order to adapt to the dynamical changeable channel condition and improve the transmissive reliability of the system, a cooperation system of rate-compatible low density parity check (RC-LDPC) codes combining with multi-relay selection protocol is proposed. In traditional relay selection protocol, only the channel state information (CSI) of source-relay and the CSI of relay-destination has been considered. The multi-relay selection protocol proposed by this paper takes the CSI between relays into extra account in order to obtain more chances of collabration. Additionally, the idea of hybrid automatic request retransmission (HARQ) and rate-compatible are introduced. Simulation results show that the transmissive reliability of the system can be significantly improved by the proposed protocol.

Robust Data Detection for the Photon-Counting Free-Space Optical System With Implicit CSI Acquisition and Background Radiation Compensation

NASA Astrophysics Data System (ADS)

Song, Tianyu; Kam, Pooi-Yuen

2016-02-01

Since atmospheric turbulence and pointing errors cause signal intensity fluctuations and the background radiation surrounding the free-space optical (FSO) receiver contributes an undesired noisy component, the receiver requires accurate channel state information (CSI) and background information to adjust the detection threshold. In most previous studies, for CSI acquisition, pilot symbols were employed, which leads to a reduction of spectral and energy efficiency; and an impractical assumption that the background radiation component is perfectly known was made. In this paper, we develop an efficient and robust sequence receiver, which acquires the CSI and the background information implicitly and requires no knowledge about the channel model information. It is robust since it can automatically estimate the CSI and background component and detect the data sequence accordingly. Its decision metric has a simple form and involves no integrals, and thus can be easily evaluated. A Viterbi-type trellis-search algorithm is adopted to improve the search efficiency, and a selective-store strategy is adopted to overcome a potential error floor problem as well as to increase the memory efficiency. To further simplify the receiver, a decision-feedback symbol-by-symbol receiver is proposed as an approximation of the sequence receiver. By simulations and theoretical analysis, we show that the performance of both the sequence receiver and the symbol-by-symbol receiver, approach that of detection with perfect knowledge of the CSI and background radiation, as the length of the window for forming the decision metric increases.

Fast determination of the current loss mechanisms in textured crystalline Si-based solar cells

NASA Astrophysics Data System (ADS)

Nakane, Akihiro; Fujimoto, Shohei; Fujiwara, Hiroyuki

2017-11-01

A quite general device analysis method that allows the direct evaluation of optical and recombination losses in crystalline silicon (c-Si)-based solar cells has been developed. By applying this technique, the current loss mechanisms of the state-of-the-art solar cells with ˜20% efficiencies have been revealed. In the established method, the optical and electrical losses are characterized from the analysis of an experimental external quantum efficiency (EQE) spectrum with very low computational cost. In particular, we have performed the EQE analyses of textured c-Si solar cells by employing the experimental reflectance spectra obtained directly from the actual devices while using flat optical models without any fitting parameters. We find that the developed method provides almost perfect fitting to EQE spectra reported for various textured c-Si solar cells, including c-Si heterojunction solar cells, a dopant-free c-Si solar cell with a MoOx layer, and an n-type passivated emitter with rear locally diffused solar cell. The modeling of the recombination loss further allows the extraction of the minority carrier diffusion length and surface recombination velocity from the EQE analysis. Based on the EQE analysis results, the current loss mechanisms in different types of c-Si solar cells are discussed.

CSI: Immigrant Children--Clues for Teacher Education

ERIC Educational Resources Information Center

Larke, Patricia J.

2012-01-01

The metaphor of the popular television shows "CSI: New York," "CSI: Miami," and "CSI: Las Vegas" (CSI stands for "crime scene investigation") is applicable to investigating issues of immigrant children in teacher preparation programs (TPP). One of the fundamental principles of CSI is to solve the crime by…

Fast inactivation of delayed rectifier K conductance in squid giant axon and its cell bodies.

PubMed

Mathes, C; Rosenthal, J J; Armstrong, G M; Gilly, W F

1997-04-01

Inactivation of delayed rectifier K conductance (gk) was studied in squid giant axons and in the somata of giant fiber lobe (GFL) neurons. Axon measurements were made with an axial wire voltage clamp by pulsing to VK (approximately -10 mV in 50-70 mM external K) for a variable time and then assaying available gK with a strong, brief test pulse. GFL cells were studied with whole-cell patch clamp using the same prepulse procedure as well as with long depolarizations. Under our experimental conditions (12-18 degrees C, 4 mM internal MgATP) a large fraction of gK inactivates within 250 ms at -10 mV in both cell bodies and axons, although inactivation tends to be more complete in cell bodies. Inactivation in both preparations shows two kinetic components. The faster component is more temperature-sensitive and becomes very prominent above 12 degrees C. Contribution of the fast component to inactivation shows a similar voltage dependence to that of gK, suggesting a strong coupling of this inactivation path to the open state. Omission of internal MgATP or application of internal protease reduces the amount of fast inactivation. High external K decreases the amount of rapidly inactivating IK but does not greatly alter inactivation kinetics. Neither external nor internal tetraethylammonium has a marked effect on inactivation kinetics. Squid delayed rectifier K channels in GFL cell bodies and giant axons thus share complex fast inactivation properties that do not closely resemble those associated with either C-type or N-type inactivation of cloned Kvl channels studied in heterologous expression systems.

Fast Inactivation of Delayed Rectifier K Conductance in Squid Giant Axon and Its Cell Bodies

PubMed Central

Mathes, Chris; Rosenthal, Joshua J.C.; Armstrong, Clay M.; Gilly, William F.

1997-01-01

Inactivation of delayed rectifier K conductance (gK) was studied in squid giant axons and in the somata of giant fiber lobe (GFL) neurons. Axon measurements were made with an axial wire voltage clamp by pulsing to VK (∼−10 mV in 50–70 mM external K) for a variable time and then assaying available gK with a strong, brief test pulse. GFL cells were studied with whole-cell patch clamp using the same prepulse procedure as well as with long depolarizations. Under our experimental conditions (12–18°C, 4 mM internal MgATP) a large fraction of gK inactivates within 250 ms at −10 mV in both cell bodies and axons, although inactivation tends to be more complete in cell bodies. Inactivation in both preparations shows two kinetic components. The faster component is more temperature-sensitive and becomes very prominent above 12°C. Contribution of the fast component to inactivation shows a similar voltage dependence to that of gK, suggesting a strong coupling of this inactivation path to the open state. Omission of internal MgATP or application of internal protease reduces the amount of fast inactivation. High external K decreases the amount of rapidly inactivating IK but does not greatly alter inactivation kinetics. Neither external nor internal tetraethylammonium has a marked effect on inactivation kinetics. Squid delayed rectifier K channels in GFL cell bodies and giant axons thus share complex fast inactivation properties that do not closely resemble those associated with either C-type or N-type inactivation of cloned Kv1 channels studied in heterologous expression systems. PMID:9101403

Sparsity-aware multiple relay selection in large multi-hop decode-and-forward relay networks

NASA Astrophysics Data System (ADS)

Gouissem, A.; Hamila, R.; Al-Dhahir, N.; Foufou, S.

2016-12-01

In this paper, we propose and investigate two novel techniques to perform multiple relay selection in large multi-hop decode-and-forward relay networks. The two proposed techniques exploit sparse signal recovery theory to select multiple relays using the orthogonal matching pursuit algorithm and outperform state-of-the-art techniques in terms of outage probability and computation complexity. To reduce the amount of collected channel state information (CSI), we propose a limited-feedback scheme where only a limited number of relays feedback their CSI. Furthermore, a detailed performance-complexity tradeoff investigation is conducted for the different studied techniques and verified by Monte Carlo simulations.

ATDM LANL FleCSI: Topology and Execution Framework

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

Bergen, Benjamin Karl

FleCSI is a compile-time configurable C++ framework designed to support multi-physics application development. As such, FleCSI attempts to provide a very general set of infrastructure design patterns that can be specialized and extended to suit the needs of a broad variety of solver and data requirements. This means that FleCSI is potentially useful to many different ECP projects. Current support includes multidimensional mesh topology, mesh geometry, and mesh adjacency information, n-dimensional hashed-tree data structures, graph partitioning interfaces, and dependency closures (to identify data dependencies between distributed-memory address spaces). FleCSI introduces a functional programming model with control, execution, and data abstractionsmore » that are consistent with state-of-the-art task-based runtimes such as Legion and Charm++. The model also provides support for fine-grained, data-parallel execution with backend support for runtimes such as OpenMP and C++17. The FleCSI abstraction layer provides the developer with insulation from the underlying runtimes, while allowing support for multiple runtime systems, including conventional models like asynchronous MPI. The intent is to give developers a concrete set of user-friendly programming tools that can be used now, while allowing flexibility in choosing runtime implementations and optimizations that can be applied to architectures and runtimes that arise in the future. This project is essential to the ECP Ristra Next-Generation Code project, part of ASC ATDM, because it provides a hierarchically parallel programming model that is consistent with the design of modern system architectures, but which allows for the straightforward expression of algorithmic parallelism in a portably performant manner.« less

Correlation between clinical signs of depth of anaesthesia and cerebral state index responses in dogs with different target-controlled infusions of propofol.

PubMed

Ribeiro, Lénio M; Ferreira, David A; Brás, Susana; Gonzalo-Orden, Jose M; Antunes, Luis M

2012-01-01

To evaluate if the cerebral state index (CSI), measured by a Cerebral State Monitor (CSM), can predict depth of anaesthesia as assessed clinically or by estimated propofol plasma concentrations. Prospective clinical study. Fourteen mixed breed dogs, weighing 24.5 ± 4.7 kg, scheduled to undergo neutering procedures. Dogs were premedicated with 0.05 mg kg(-1) acepromazine intramuscularly. The CSM and cardiovascular monitoring equipment were attached. Anaesthesia was induced with propofol using a target controlled infusion (TCI) to varying plasma propofol targets (PropCp). Following endotracheal intubation the dogs were ventilated with oxygen. Anaesthetic maintenance was with propofol by TCI. A PropCp of 3 μg dL(-1) was set initially, then PropCps were increased in 1 μg dL(-1) steps to 7, 9 and then 11 μg dL(-1). Each PropCp was held constant for a 5 minute period, at the end of which depth of anaesthesia was classified using a previously evaluated scale of 'planes' based on palpebral and corneal reflexes and eye position. Cerebral state index (CSI), burst suppression (BSR) and electromyogram were measured at these time points. The prediction probability (PK) of these variables, or of the PropCp in predicting depth of anaesthesia was calculated. The PKs for predicting anaesthetic planes were 0.74, 0.91, 0.76 and 0.78 for CSI, BSR, EMG and PropCp, respectively. The PKs for PropCp to predict CSI, BSR and EMG were 0.65, 0.71 and 0.65 respectively. The Cerebral State Monitor was able to detect very deep planes of anaesthesia when BSR occurs, but was not able to distinguish between the intermediate anaesthetic planes likely to be used in clinical anaesthesia. © 2011 The Authors. Veterinary Anaesthesia and Analgesia. © 2011 Association of Veterinary Anaesthetists and the American College of Veterinary Anesthesiologists.

Multi-pair two-way massive MIMO AF relaying with ZFR/ZFT beamforming and imperfect CSI over ricean fading channels

NASA Astrophysics Data System (ADS)

Xu, Kui; Sun, Xiaoli; Zhang, Dongmei

2016-10-01

This paper investigates the spectral and energy efficiencies of a multi-pair two-way amplify-and-forward (AF) relay system over Ricean fading channels, where multiple user-pairs exchange information within pair through a relay with very large number of antennas, while each user equipped with a single antenna. Firstly, beamforming matrixe of zero-forcing reception/zero-forcing transmission (ZFR/ZFT) with imperfect channel state information (CSI) at the relay is given. Then, the unified asymptotic signal-to-interference-plus-noise ratio (SINR) expressions with imperfect CSI are obtained analytically. Finally, two power scaling schemes are proposed and the asymptotic spectral and energy efficiencies based on the proposed power scaling schemes are derived and verified by the Monte-Carlo simulations. Theoretical analyses and simulation results show that with imperfect CSI, if the number of relay antennas grows asymptotically large, we need cut down the transmit power of each user and relay to different proportion when the Ricean K-factor is non-zero and zero (Rayleigh fading) in order to maintain a desirable rate.

Occupant and crash characteristics for case occupants with cervical spine injuries sustained in motor vehicle collisions.

PubMed

Stein, Deborah M; Kufera, Joseph A; Ho, Shiu M; Ryb, Gabriel E; Dischinger, Patricia C; O'Connor, James V; Scalea, Thomas M

2011-02-01

Motor vehicle collisions (MVCs) are the leading cause of spine and spinal cord injuries in the United States. Traumatic cervical spine injuries (CSIs) result in significant morbidity and mortality. This study was designed to evaluate both the epidemiologic and biomechanical risk factors associated with CSI in MVCs by using a population-based database and to describe occupant and crashes characteristics for a subset of severe crashes in which a CSI was sustained as represented by the Crash Injury Research Engineering Network (CIREN) database. Prospectively collected CIREN data from the eight centers were used to identify all case occupants between 1996 and November 2009. Case occupants older than 14 years and case vehicles of the four most common vehicle types were included. The National Automotive Sampling System's Crashworthiness Data System, a probability sample of all police-reported MVCs in the United States, was queried using the same inclusion criteria between 1997 and 2008. Cervical spinal cord and spinal column injuries were identified using Abbreviated Injury Scale (AIS) score codes. Data were abstracted on all case occupants, biomechanical crash characteristics, and injuries sustained. Univariate analysis was performed using a χ analysis. Logistic regression was used to identify significant risk factors in a multivariate analysis to control for confounding associations. CSIs were identified in 11.5% of CIREN case occupants. Case occupants aged 65 years or older and those occupants involved in rollover crashes were more likely to sustain a CSI. In univariate analysis of the subset of severe crashes represented by CIREN, the use of airbag and seat belt together (reference) were more protective than seat belt alone (odds ratio [OR]=1.73, 95% confidence interval [CI]=1.32-2.27) or the use of neither restraint system (OR=1.45, 95% CI=1.02-2.07). The most frequent injury sources in CIREN crashes were roof and its components (24.8%) and noncontact sources (15.5%). In multivariate analysis, age, rollover impact, and airbag-only restraint systems were associated with an increased odds of CSI. Using the population-based National Automotive Sampling System's Crashworthiness Data System data, 0.35% of occupants sustained a CSI. In univariate analysis, older age was noted to be a significant risk factor for CSI. Airbag-only restraint systems and both rollover and lateral crashes were also identified as risk factors for CSI. In addition, increasing delta v was highly associated with CSIs. In multivariate analysis, similar risk factors were noted. Of all the restraint systems, seat belt use without airbag deployment was found to be the most protective restraint system (OR=0.29, 95% CI=0.16-0.50), whereas airbag-only restraint was associated with the highest risk of CSI (OR=3.54, 95% CI=2.29-5.46). Despite advances in automotive safety, CSIs sustained in MVC continue to occur too often. Older case occupants are at an increased risk of CSI. Rollover crashes and severe crashes led to a much higher risk of CSI than other types and severity of MVCs. Seat belt use is very effective in preventing CSI, whereas airbag deployment may increase the risk of occupants sustaining a CSI. More protection for older occupants is needed and protection in both rollover and lateral crashes should remain a focus of the automotive industry. The design of airbag restraint systems should be evaluated so that they are not causative of serious injury. In addition, engineers should continue to focus on improving automotive design to minimize the risk of spinal injury to occupants in high severity crashes.

A survey of experiments and experimental facilities for active control of flexible structures

NASA Technical Reports Server (NTRS)

Sparks, Dean W., Jr.; Horner, Garnett C.; Juang, Jer-Nan; Klose, Gerhard

1989-01-01

A brief survey of large space structure control related experiments and facilities was presented. This survey covered experiments performed before and up to 1982, and those of the present period (1982-...). Finally, the future planned experiments and facilities in support of the control-structure interaction (CSI) program were reported. It was stated that new, improved ground test facilities are needed to verify the new CSI design techniques that will allow future space structures to perform planned NASA missions.

Reaction of Chlorosulfonyl Isocyanate (CSI) with Fluorosubstituted Alkenes: Evidence of a Concerted Pathway for Reaction of CSI with Fluorosubstituted Alkenes (Preprint)

DTIC Science & Technology

2010-06-01

ABSTRACT Concerted reactions are indicated for the electrophilic addition of chlorosulfonyl isocyanate with monofluoroalkenes. A vinyl fluorine atom on...SO2Cl R F O ‡ N SO2Cl F R O Abstract: Concerted reactions are indicated for the electrophilic addition of chlorosulfonyl isocyanate with...monofluoroalkenes. A vinyl fluorine atom on an alkene raises the energy of a step-wise transition state more than the energy of the competing concerted

A review of dosimetric and toxicity modeling of proton versus photon craniospinal irradiation for pediatrics medulloblastoma.

PubMed

Ho, Evangeline S Q; Barrett, Sarah A; Mullaney, Laura M

2017-08-01

Craniospinal irradiation (CSI) is the standard radiation therapy treatment for medulloblastoma. Conventional CSI photon therapy (Photon-CSI) delivers significant dose to surrounding normal tissue (NT). Research into pediatric CSI with proton therapy (Proton-CSI) has increased, with the aim of exploiting the potential to reduce NT dose and associated post-treatment complications. This review aims to compare treatment outcomes of pediatric medulloblastoma patients between Proton- and Photon-CSI treatments. A search and review of studies published between 1990 and 2016 comparing pediatric (2-18 years) medulloblastoma Proton- and Photon-CSI in three aspects - normal organ sparing and target coverage; normal organ dysfunction and second malignancy risks - was completed. Fifteen studies were selected for review and the results were directly compared. Proton-CSI reported improved out-of-field organ sparing while target coverage improvements were inconsistent. Normal organ dysfunction risks were predicted to be lower following Proton-CSI. Secondary malignancy risks (SMRs) were generally lower with Proton-CSI based on several different risk models. Proton-CSI conferred better treatment outcomes than Photon-CSI for pediatric medulloblastoma patients. This review serves to compare the current literature in the absence of long-term data from prospective studies.

Dynamic tests on the NASA Langley CSI evolutionary model

NASA Technical Reports Server (NTRS)

Troidl, H.; Elliott, K. B.

1993-01-01

A modal analysis study, representing one of the anticipated 'Cooperative Spacecraft Structural Dynamics Experiments on the NASA Langley CSI Evolutionary Model', was carried out as a sub-task under the NASA/DLR collaboration in dynamics and control of large space systems. The CSI evolutionary testbed (CEM) is designed for the development of Controls-Structures Interaction (CSI) technology to improve space science platform pointing. For orbiting space structures like large flexible trusses, new identification challenges arise due to their specific dynamic characteristics (low frequencies and high modal density) on the one hand, and the limited possibilities of exciting such structures and measuring their responses on orbit on the other. The main objective was to investigate the modal identification potential of several different types of forcing functions that could possibly be realized with on-board excitation equipment using a minimum number of exciter locations as well as response locations. These locations were defined in an analytical test prediction process used to study the implications of measuring and analyzing the responses thus produced. It turned out that broadband excitation is needed for a general modal survey, but if only certain modes are of particular interest, combinations of exponentially decaying sine functions provide favorable excitation conditions as they allow to concentrate the available energy on the modes being of special interest. From a practical point-of-view structural nonlinearities as well as noisy measurements make the analysis more difficult, especially in the low frequency range and when the modes are closely spaced.

CSI feedback-based CS for underwater acoustic adaptive modulation OFDM system with channel prediction

NASA Astrophysics Data System (ADS)

Kuai, Xiao-yan; Sun, Hai-xin; Qi, Jie; Cheng, En; Xu, Xiao-ka; Guo, Yu-hui; Chen, You-gan

2014-06-01

In this paper, we investigate the performance of adaptive modulation (AM) orthogonal frequency division multiplexing (OFDM) system in underwater acoustic (UWA) communications. The aim is to solve the problem of large feedback overhead for channel state information (CSI) in every subcarrier. A novel CSI feedback scheme is proposed based on the theory of compressed sensing (CS). We propose a feedback from the receiver that only feedback the sparse channel parameters. Additionally, prediction of the channel state is proposed every several symbols to realize the AM in practice. We describe a linear channel prediction algorithm which is used in adaptive transmission. This system has been tested in the real underwater acoustic channel. The linear channel prediction makes the AM transmission techniques more feasible for acoustic channel communications. The simulation and experiment show that significant improvements can be obtained both in bit error rate (BER) and throughput in the AM scheme compared with the fixed Quadrature Phase Shift Keying (QPSK) modulation scheme. Moreover, the performance with standard CS outperforms the Discrete Cosine Transform (DCT) method.

Anesthetic influence on occurrence and treatment of the trigemino-cardiac reflex: a systematic literature review.

PubMed

Meuwly, Cyrill; Chowdhury, Tumul; Sandu, Nora; Reck, Martin; Erne, Paul; Schaller, Bernhard

2015-05-01

Trigeminocardiac reflex (TCR) is defined as sudden onset of parasympathetic dysrhythmia including hypotension, apnea, and gastric hypermotility during stimulation of any branches of the trigeminal nerve. Previous publications imply a relation between TCR and depth of anesthesia. To gain more detailed insights into this hypothesis, we performed a systematic literature review.Literature about occurrence of TCR was systematically identified through searching in Cochrane Central Register of Controlled Trials (CENTRAL), PubMed (MEDLINE), EMBASE (Ovid SP), and the Institute for Scientific Information (ISI Web of Sciences) databases until June 2013, as well as reference lists of articles for risk calculation. In this study, TCR was defined as drop in mean arterial blood pressure and heart rate, both >20% to baseline. We calculated intraoperative cerebral state index (CSI) of each TCR-case using a newly developed method. These data were further divided into 3 subgroups: CSI <40 (deep anesthesia), CSI 40-60 (regular anesthesia), and CSI >60 (slight anesthesia).Including 45 studies with 910 patients, 140 (15%) presented with TCR, and 770 (85%) without TCR during operation. TCR occurrence showed a 1.2-fold higher pooled risk slighter anesthesia (CSI <40: 13%, at CSI 40-60: 21%, and at CSI >60: 27%) compared with deeper anesthesia. In addition, we could discover a 1.3-fold higher pooled risk of higher MABP drop with a strong negative correlation (r = -0.935; r = 0.89) and a 4.5-fold higher pooled risk of asystole during TCR under slight anesthesia compared with deeper anesthesia.Our work is the first systematic review about TCR and demonstrates clear evidence for TCR occurrence and a more severe course of the TCR in slight anesthesia underlying the importance of skills in anesthesia management during skull base surgery. Furthermore, we have introduced a new standard method to calculate the depth of anesthesia.

A Cycling Movement Based System for Real-Time Muscle Fatigue and Cardiac Stress Monitoring and Analysis

PubMed Central

Chen, Szi-Wen; Liaw, Jiunn-Woei; Chang, Ya-Ju; Chan, Hsiao-Lung; Chiu, Li-Yu

2015-01-01

In this study, we defined a new parameter, referred to as the cardiac stress index (CSI), using a nonlinear detrended fluctuation analysis (DFA) of heart rate (HR). Our study aimed to incorporate the CSI into a cycling based fatigue monitoring system developed in our previous work so the muscle fatigue and cardiac stress can be both continuously and quantitatively assessed for subjects undergoing the cycling exercise. By collecting electrocardiogram (ECG) signals, the DFA scaling exponent α was evaluated on the RR time series extracted from a windowed ECG segment. We then obtained the running estimate of α by shifting a one-minute window by a step of 20 seconds so the CSI, defined as the percentage of all the less-than-one α values, can be synchronously updated every 20 seconds. Since the rating of perceived exertion (RPE) scale is considered as a convenient index which is commonly used to monitor subjective perceived exercise intensity, we then related the Borg RPE scale value to the CSI in order to investigate and quantitatively characterize the relationship between exercise-induced fatigue and cardiac stress. Twenty-two young healthy participants were recruited in our study. Each participant was asked to maintain a fixed pedaling speed at a constant load during the cycling exercise. Experimental results showed that a decrease in DFA scaling exponent α or an increase in CSI was observed during the exercise. In addition, the Borg RPE scale and CSI were positively correlated, suggesting that the factors due to cardiac stress might also contribute to fatigue state during physical exercise. Since the CSI can effectively quantify the cardiac stress status during physical exercise, our system may be used in sports medicine, or used by cardiologists who carried out stress tests for monitoring heart condition in patients with heart diseases. PMID:26115515

Temperature Effects of Electric Field on the First Excited State of Strong Coupling Polaron in a CsI Quantum Pseudodot

NASA Astrophysics Data System (ADS)

Sun, Yong; Ding, Zhao-Hua; Xiao, Jing-Lin

2017-03-01

Employing variational method of Pekar type (VMPT), this paper investigates the first-excited state energy (FESE), excitation energy and transition frequency of the strongly-coupled polaron in the CsI quantum pseudodot (QPD) with electric field. The temperature effects on the strong-coupling polaron in electric field are calculated by using the quantum statistical theory (QST). The results from the present investigation show that the FESE, excitation energy and transition frequency increase (decrease) firstly and then at lower (higher) temperature regions. They are decreasing functions of the electric field strength. Supported by the National Natural Science Foundation of China under Grant No. 11464033

Children's Somatization Inventory: Psychometric Properties of the Revised Form (CSI-24)

PubMed Central

Beck, Joy E.; Garber, Judy; Lambert, Warren

2009-01-01

Objective To conduct a multimethod psychometric evaluation to refine the Children's Somatization Inventory (CSI) and to investigate its dimensionality. Method The CSI was administered to 876 pediatric patients with chronic abdominal pain at their initial visit to a pediatric gastroenterology clinic. Tools from three psychometric models identified items that most effectively measured the construct of somatization and examined its dimensionality. Results Eleven statistically weak items were identified and removed, creating a 24-item CSI (CSI-24). The CSI-24 showed good psychometrics according to the three measurement models and correlated.99 with the original CSI. The CSI-24 has one dominant general factor but is not strictly unidimensional. Conclusions The CSI-24 is a reliable and psychometrically sound refinement of the original CSI. Findings are consistent with the view that somatization has a strong general factor that represents a continuum of symptom reporting, as well as minor components that represent specific symptom clusters in youth with chronic abdominal pain. PMID:18782857

Experimental evaluation of active-member control of precision structures

NASA Technical Reports Server (NTRS)

Fanson, James; Blackwood, Gary; Chu, Cheng-Chih

1989-01-01

The results of closed loop experiments that use piezoelectric active-members to control the flexible motion of a precision truss structure are described. These experiments are directed toward the development of high-performance structural systems as part of the Control/Structure Interaction (CSI) program at JPL. The focus of CSI activity at JPL is to develop the technology necessary to accurately control both the shape and vibration levels in the precision structures from which proposed large space-based observatories will be built. Structural error budgets for these types of structures will likely be in the sub-micron regime; optical tolerances will be even tighter. In order to achieve system level stability and local positioning at this level, it is generally expected that some form of active control will be required.

Fast- or Slow-inactivated State Preference of Na+ Channel Inhibitors: A Simulation and Experimental Study

PubMed Central

Karoly, Robert; Lenkey, Nora; Juhasz, Andras O.; Vizi, E. Sylvester; Mike, Arpad

2010-01-01

Sodium channels are one of the most intensively studied drug targets. Sodium channel inhibitors (e.g., local anesthetics, anticonvulsants, antiarrhythmics and analgesics) exert their effect by stabilizing an inactivated conformation of the channels. Besides the fast-inactivated conformation, sodium channels have several distinct slow-inactivated conformational states. Stabilization of a slow-inactivated state has been proposed to be advantageous for certain therapeutic applications. Special voltage protocols are used to evoke slow inactivation of sodium channels. It is assumed that efficacy of a drug in these protocols indicates slow-inactivated state preference. We tested this assumption in simulations using four prototypical drug inhibitory mechanisms (fast or slow-inactivated state preference, with either fast or slow binding kinetics) and a kinetic model for sodium channels. Unexpectedly, we found that efficacy in these protocols (e.g., a shift of the “steady-state slow inactivation curve”), was not a reliable indicator of slow-inactivated state preference. Slowly associating fast-inactivated state-preferring drugs were indistinguishable from slow-inactivated state-preferring drugs. On the other hand, fast- and slow-inactivated state-preferring drugs tended to preferentially affect onset and recovery, respectively. The robustness of these observations was verified: i) by performing a Monte Carlo study on the effects of randomly modifying model parameters, ii) by testing the same drugs in a fundamentally different model and iii) by an analysis of the effect of systematically changing drug-specific parameters. In patch clamp electrophysiology experiments we tested five sodium channel inhibitor drugs on native sodium channels of cultured hippocampal neurons. For lidocaine, phenytoin and carbamazepine our data indicate a preference for the fast-inactivated state, while the results for fluoxetine and desipramine are inconclusive. We suggest that conclusions based on voltage protocols that are used to detect slow-inactivated state preference are unreliable and should be re-evaluated. PMID:20585544

MarkoLAB: A simulator to study ionic channel's stochastic behavior.

PubMed

da Silva, Robson Rodrigues; Goroso, Daniel Gustavo; Bers, Donald M; Puglisi, José Luis

2017-08-01

Mathematical models of the cardiac cell have started to include markovian representations of the ionic channels instead of the traditional Hodgkin & Huxley formulations. There are many reasons for this: Markov models are not restricted to the idea of independent gates defining the channel, they allow more complex description with specific transitions between open, closed or inactivated states, and more importantly those states can be closely related to the underlying channel structure and conformational changes. We used the LabVIEW ® and MATLAB ® programs to implement the simulator MarkoLAB that allow a dynamical 3D representation of the markovian model of the channel. The Monte Carlo simulation was used to implement the stochastic transitions among states. The user can specify the voltage protocol by setting the holding potential, the step-to voltage and the duration of the stimuli. The most studied feature of a channel is the current flowing through it. This happens when the channel stays in the open state, but most of the time, as revealed by the low open probability values, the channel remains on the inactive or closed states. By focusing only when the channel enters or leaves the open state we are missing most of its activity. MarkoLAB proved to be quite useful to visualize the whole behavior of the channel and not only when the channel produces a current. Such dynamic representation provides more complete information about channel kinetics and will be a powerful tool to demonstrate the effect of gene mutations or drugs on the channel function. MarkoLAB provides an original way of visualizing the stochastic behavior of a channel. It clarifies concepts, such as recovery from inactivation, calcium- versus voltage-dependent inactivation, and tail currents. It is not restricted to ionic channels only but it can be extended to other transporters, such as exchangers and pumps. This program is intended as a didactical tool to illustrate the dynamical behavior of a channel. It has been implemented in two platforms MATLAB ® and LabVIEW ® to enhance the target users of this new didactical tool. The computational cost of implementing a stochastic simulation is within the range of a personal computer performance; making MarkoLAB suitable to be run during a lecture or presentation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Two-way DF relaying assisted D2D communication: ergodic rate and power allocation

NASA Astrophysics Data System (ADS)

Ni, Yiyang; Wang, Yuxi; Jin, Shi; Wong, Kai-Kit; Zhu, Hongbo

2017-12-01

In this paper, we investigate the ergodic rate for a device-to-device (D2D) communication system aided by a two-way decode-and-forward (DF) relay node. We first derive closed-form expressions for the ergodic rate of the D2D link under asymmetric and symmetric cases, respectively. We subsequently discuss two special scenarios including weak interference case and high signal-to-noise ratio case. Then we derive the tight approximations for each of the considered scenarios. Assuming that each transmitter only has access to its own statistical channel state information (CSI), we further derive closed-form power allocation strategy to improve the system performance according to the analytical results of the ergodic rate. Furthermore, some insights are provided for the power allocation strategy based on the analytical results. The strategies are easy to compute and require to know only the channel statistics. Numerical results show the accuracy of the analysis results under various conditions and test the availability of the power allocation strategy.

Soaping the NMDA receptor: Various types of detergents influence differently [(3)H]MK-801 binding to rat brain membranes.

PubMed

Berger, Michael L

2016-01-01

Membranes prepared from rat brain were treated with increasing concentrations of cationic, neutral, anionic and zwitterionic surfactants. Potent inactivation of [(3)H]MK-801 binding to NMDA receptors (NRs) was provided by the cation cetyl pyridinium (IC50 25 μM) and the neutral digitonin (IC50 37 μM). A 2 h incubation of rat brain membranes at 24°C with 100 μM of the neutral Triton X-100 resulted in about 50% reversible inhibition (without inactivation). Reversible inhibition was also effected by the anion deoxycholate (IC50 700 μM), and by the zwitterions N-lauryl sulfobetaine (12-SB(±), 400 μM) and CHAPS (1.5 mM), with inactivation at higher concentrations. Keeping the NR cation channel in the closed state significantly protected against inactivation by cations and by 12-SB(±), but not by the other detergents. Inactivation depended differentially on the amount of the membranes, on the duration of the treatment, and on the temperature. Varying the amount of membranes by a factor 8 yielded for cetyl trimethylammonium (16-NMe3(+)) IC50s of inactivation from 10 to 80 μM, while for deoxycholate the IC50 of inactivation was 1.2 mM for all tissue quantities. Some compounds inactivated within a few min (16-NMe3(+), digitonin, CHAPS), while inactivation by others took at least half an hour (Triton X-100, deoxycholate, 12-SB(±)). These last 3 ones also exhibited the steepest temperature dependence. Knowledge about the influence of various parameters is helpful in selecting appropriate conditions allowing the treatment of brain membranes with amphiphiles without risking irreversible inactivation. Copyright © 2015 Elsevier B.V. All rights reserved.

Lacosamide Inhibition of Nav1.7 Voltage-Gated Sodium Channels: Slow Binding to Fast-Inactivated States

PubMed Central

Jo, Sooyeon

2017-01-01

Lacosamide is an antiseizure agent that targets voltage-dependent sodium channels. Previous experiments have suggested that lacosamide is unusual in binding selectively to the slow-inactivated state of sodium channels, in contrast to drugs like carbamazepine and phenytoin, which bind tightly to fast-inactivated states. Using heterologously expressed human Nav1.7 sodium channels, we examined the state-dependent effects of lacosamide. Lacosamide induced a reversible shift in the voltage dependence of fast inactivation studied with 100-millisecond prepulses, suggesting binding to fast-inactivated states. Using steady holding potentials, lacosamide block was very weak at −120 mV (3% inhibition by 100 µM lacosamide) but greatly enhanced at −80 mV (43% inhibition by 100 µM lacosamide), where there is partial fast inactivation but little or no slow inactivation. During long depolarizations, lacosamide slowly (over seconds) put channels into states that recovered availability slowly (hundreds of milliseconds) at −120 mV. This resembles enhancement of slow inactivation, but the effect was much more pronounced at −40 mV, where fast inactivation is complete, but slow inactivation is not, than at 0 mV, where slow inactivation is maximal, more consistent with slow binding to fast-inactivated states than selective binding to slow-inactivated states. Furthermore, inhibition by lacosamide was greatly reduced by pretreatment with 300 µM lidocaine or 300 µM carbamazepine, suggesting that lacosamide, lidocaine, and carbamazepine all bind to the same site. The results suggest that lacosamide binds to fast-inactivated states in a manner similar to other antiseizure agents but with slower kinetics of binding and unbinding. PMID:28119481

Lacosamide Inhibition of Nav1.7 Voltage-Gated Sodium Channels: Slow Binding to Fast-Inactivated States.

PubMed

Jo, Sooyeon; Bean, Bruce P

2017-04-01

Lacosamide is an antiseizure agent that targets voltage-dependent sodium channels. Previous experiments have suggested that lacosamide is unusual in binding selectively to the slow-inactivated state of sodium channels, in contrast to drugs like carbamazepine and phenytoin, which bind tightly to fast-inactivated states. Using heterologously expressed human Nav1.7 sodium channels, we examined the state-dependent effects of lacosamide. Lacosamide induced a reversible shift in the voltage dependence of fast inactivation studied with 100-millisecond prepulses, suggesting binding to fast-inactivated states. Using steady holding potentials, lacosamide block was very weak at -120 mV (3% inhibition by 100 µ M lacosamide) but greatly enhanced at -80 mV (43% inhibition by 100 µ M lacosamide), where there is partial fast inactivation but little or no slow inactivation. During long depolarizations, lacosamide slowly (over seconds) put channels into states that recovered availability slowly (hundreds of milliseconds) at -120 mV. This resembles enhancement of slow inactivation, but the effect was much more pronounced at -40 mV, where fast inactivation is complete, but slow inactivation is not, than at 0 mV, where slow inactivation is maximal, more consistent with slow binding to fast-inactivated states than selective binding to slow-inactivated states. Furthermore, inhibition by lacosamide was greatly reduced by pretreatment with 300 µ M lidocaine or 300 µ M carbamazepine, suggesting that lacosamide, lidocaine, and carbamazepine all bind to the same site. The results suggest that lacosamide binds to fast-inactivated states in a manner similar to other antiseizure agents but with slower kinetics of binding and unbinding. Copyright © 2017 by The American Society for Pharmacology and Experimental Therapeutics.

Perception-Induced Effects of Corporate Social Irresponsibility (CSiR) for Stereotypical and Admired Firms

PubMed Central

Voliotis, Seraphim; Vlachos, Pavlos A.; Epitropaki, Olga

2016-01-01

How do stakeholders react to Corporate Social Irresponsibility (CSiR)? What are the emotional mechanisms and behavioral outcomes following CSiR perception? The psychology of CSR literature has yet to address these important questions and has largely considered CSR and CSiR as the opposite poles of the same continuum. In contrast, we view CSR and CSiR as distinct constructs and theorize about the cognitive (perceptual), emotional, and behavioral effects of CSiR activity on observers (i.e., primary and secondary stakeholders) building on theories of intergroup perception. Specifically, building on the Stereotype Content Model (SCM; Fiske et al., 2002) and the BIAS map (i.e., Behaviors from Intergroup Affect and Stereotypes; Cuddy et al., 2007)—which extends the SCM by predicting behavioral responses—we make predictions on potential stakeholder reactions to CSiR focusing on two practice-relevant cases: (a) a typical for-profit firm that engages in a CSiR activity, (b) an atypical admired firm that engages in CSiR activity. PMID:27445931

Perception-Induced Effects of Corporate Social Irresponsibility (CSiR) for Stereotypical and Admired Firms.

PubMed

Voliotis, Seraphim; Vlachos, Pavlos A; Epitropaki, Olga

2016-01-01

How do stakeholders react to Corporate Social Irresponsibility (CSiR)? What are the emotional mechanisms and behavioral outcomes following CSiR perception? The psychology of CSR literature has yet to address these important questions and has largely considered CSR and CSiR as the opposite poles of the same continuum. In contrast, we view CSR and CSiR as distinct constructs and theorize about the cognitive (perceptual), emotional, and behavioral effects of CSiR activity on observers (i.e., primary and secondary stakeholders) building on theories of intergroup perception. Specifically, building on the Stereotype Content Model (SCM; Fiske et al., 2002) and the BIAS map (i.e., Behaviors from Intergroup Affect and Stereotypes; Cuddy et al., 2007)-which extends the SCM by predicting behavioral responses-we make predictions on potential stakeholder reactions to CSiR focusing on two practice-relevant cases: (a) a typical for-profit firm that engages in a CSiR activity, (b) an atypical admired firm that engages in CSiR activity.

Monitoring of anesthetic depth during surgical correction of acquired valvular disorders: single center, randomized trial.

PubMed

Lenkin, Andrey I; Zaharov, Viktor I; Lenkin, Pavel I; Smetkin, Alexey A; Bjertnaes, Lars J; Kirov, Mikhail Y

2014-04-01

The authors' primary objective was to test the hypothesis that Cerebral State Index (CSI)-guided control of anesthetic depth might reduce the consumption of anesthetics and shorten the duration of ICU and hospital stays after surgical correction of combined valve disorders. Single center, randomized trial. City Hospital Number 1 of Arkhangelsk, Russian Federation. Fifty adult patients with combined valve disorders requiring surgical correction. The patients were randomized into 2 groups. In the CSI group, anesthetic depth was monitored, and the rate of infusion of propofol was titrated to maintain the depth of anesthesia corresponding to a CSI of 40-60. In the control group, the depth of anesthesia was monitored clinically, and the dosage of propofol was administered according to the recommendations of the manufacturer. All patients received standard perioperative monitoring. Consumption of anesthetics and length of ICU and hospital stays were recorded. Preoperative patient characteristics did not differ significantly between the groups. In the CSI group, average intraoperative doses of midazolam and propofol were reduced by 41% and 19%, respectively (p<0.01). Maintenance of anesthesia guided by CSI shortened the time until fit for ICU discharge by 50% and reduced the lengths of ICU and postoperative hospital stays by 35% and 25%, respectively (p< 0.05). Monitoring of anesthetic depth reduces the requirements for midazolam and propofol, resulting in a faster recovery and a shorter postoperative ICU and hospital stay after surgical correction of combined valve disorders. Copyright © 2014 Elsevier Inc. All rights reserved.

Power Allocation Based on Data Classification in Wireless Sensor Networks

PubMed Central

Wang, Houlian; Zhou, Gongbo

2017-01-01

Limited node energy in wireless sensor networks is a crucial factor which affects the monitoring of equipment operation and working conditions in coal mines. In addition, due to heterogeneous nodes and different data acquisition rates, the number of arriving packets in a queue network can differ, which may lead to some queue lengths reaching the maximum value earlier compared with others. In order to tackle these two problems, an optimal power allocation strategy based on classified data is proposed in this paper. Arriving data is classified into dissimilar classes depending on the number of arriving packets. The problem is formulated as a Lyapunov drift optimization with the objective of minimizing the weight sum of average power consumption and average data class. As a result, a suboptimal distributed algorithm without any knowledge of system statistics is presented. The simulations, conducted in the perfect channel state information (CSI) case and the imperfect CSI case, reveal that the utility can be pushed arbitrarily close to optimal by increasing the parameter V, but with a corresponding growth in the average delay, and that other tunable parameters W and the classification method in the interior of utility function can trade power optimality for increased average data class. The above results show that data in a high class has priorities to be processed than data in a low class, and energy consumption can be minimized in this resource allocation strategy. PMID:28498346

Transmit Designs for the MIMO Broadcast Channel With Statistical CSI

NASA Astrophysics Data System (ADS)

Wu, Yongpeng; Jin, Shi; Gao, Xiqi; McKay, Matthew R.; Xiao, Chengshan

2014-09-01

We investigate the multiple-input multiple-output broadcast channel with statistical channel state information available at the transmitter. The so-called linear assignment operation is employed, and necessary conditions are derived for the optimal transmit design under general fading conditions. Based on this, we introduce an iterative algorithm to maximize the linear assignment weighted sum-rate by applying a gradient descent method. To reduce complexity, we derive an upper bound of the linear assignment achievable rate of each receiver, from which a simplified closed-form expression for a near-optimal linear assignment matrix is derived. This reveals an interesting construction analogous to that of dirty-paper coding. In light of this, a low complexity transmission scheme is provided. Numerical examples illustrate the significant performance of the proposed low complexity scheme.

Transitioning the California Energy Commission Eligible Equipment List to a National Platform

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

Truitt, Sarah; Nobler, Erin; Krasko, Vitaliy

The Energy Commission called on the National Renewable Energy Laboratory's (NREL)'s Solar Technical Assistance Team to explore various pathways for supporting continued evolution of the list. NREL staff utilized the Database of State Incentives for Renewables and Efficiency (DSIRE), California Solar Initiative (CSI) data, and information from in-depth interviews to better understand the impact of a lack of an updated list and suggest potential solutions. A total of 18 people from state energy offices, rebate program administrators, utilities, national testing laboratories, private companies, nonprofit organizations, and the federal government were interviewed between July and September 2013. CSI data were analyzedmore » to illustrate the monetary benefits of the algorithm behind calculating performance of PV modules included on the list. The primary objectives of this study are to: 1) Determine the impact of not maintaining the list, and 2) Explore alternatives to the State of California's maintenance of the list.« less

Flash Inactivation of Oxygen Evolution

PubMed Central

Frasch, Wayne D.; Cheniae, George M.

1980-01-01

Brief saturating light flashes were used to probe the mechanism of inactivation of O2 evolution by Tris in chloroplasts. Maximum inactivation with a single flash and an oscillation with period of four on subsequent flashes was observed. Analyses of the oscillations suggested that only the charge-collecting O2-evolving catalyst of photosystem II (S2-state) was a target of inactivation by Tris. This conclusion was supported by the following observations: (a) hydroxylamine preequilibration caused a three-flash delay in the inactivation pattern; (b) the lifetimes of the Tris-inactivable and S2-states were similar; and (c) reagents accelerating S2 deactivation decreased the lifetime of the inactivable state. Inactivation proved to be moderated by F, the precursor of Signal IIs, as shown by a one flash delay with chloroplasts having high abundance of F. Evidence was obtained for cooperativity effects in inactivation and NH3 was shown to be a competitive inhibitor of the Tris-induced inactivation. S2-dependent inactivation was inhibited by glutaraldehyde fixation of chloroplasts, possibly suggesting that inactivation proceeds via conformational changes of the S2-state. PMID:16661270

Surface physicochemical properties and decay of the low-lying isomer in the 229Th nucleus

NASA Astrophysics Data System (ADS)

Borisyuk, P. V.; Kurel'chuk, U. N.; Vasil'ev, O. S.; Troyan, V. I.; Lebedinskii, Yu Yu; Tkalya, E. V.

2018-05-01

The effect of the 229Th nucleus proximity to the CsI surface on the decay probability of its anomalously low lying isomeric level is studied. Results of experimental and theoretical studies show that the CsI surface does not produce chemical bonding with Th and does not noticeably change its valence shells. Hence, it is an optimal substrate for measuring the probability of the 229Th isomer state decay via internal electron conversion. The half-life of the 229Thm isomer in the thorium atom is calculated for neutral chemical environment.

A Scalable Framework for CSI Feedback in FDD Massive MIMO via DL Path Aligning

NASA Astrophysics Data System (ADS)

Luo, Xiliang; Cai, Penghao; Zhang, Xiaoyu; Hu, Die; Shen, Cong

2017-09-01

Unlike the time-division duplexing (TDD) systems, the downlink (DL) and uplink (UL) channels are not reciprocal anymore in the case of frequency-division duplexing (FDD). However, some long-term parameters, e.g. the time delays and angles of arrival (AoAs) of the channel paths, still enjoy reciprocity. In this paper, by efficiently exploiting the aforementioned limited reciprocity, we address the DL channel state information (CSI) feedback in a practical wideband massive multiple-input multiple-output (MIMO) system operating in the FDD mode. With orthogonal frequency-division multiplexing (OFDM) waveform and assuming frequency-selective fading channels, we propose a scalable framework for the DL pilots design, DL CSI acquisition, and the corresponding CSI feedback in the UL. In particular, the base station (BS) can transmit the FFT-based pilots with the carefully-selected phase shifts. Then the user can rely on the so-called time-domain aggregate channel (TAC) to derive the feedback of reduced imensionality according to either its own knowledge about the statistics of the DL channels or the instruction from the serving BS. We demonstrate that each user can just feed back one scalar number per DL channel path for the BS to recover the DL CSIs. Comprehensive numerical results further corroborate our designs.

Construction of a North American Cancer Survival Index to Measure Progress of Cancer Control Efforts

PubMed Central

Weir, Hannah K; Mariotto, Angela; Wilson, Reda; Nishri, Diane

2017-01-01

Introduction Population-based cancer survival data provide insight into the effectiveness of health care delivery. Comparing survival for all cancer sites combined is challenging, because the primary cancer site and age distribution of patients may differ among areas or change over time. Cancer survival indices (CSIs) are summary measures of survival for cancers of all sites combined and are used in England and Europe to monitor temporal trends and examine geographic differences in survival. We describe the construction of the North American Cancer Survival Index and demonstrate how it can be used to compare survival by geographic area and by race. Methods We used data from 36 US cancer registries to estimate relative survival ratios for people diagnosed with cancer from 2006 through 2012 to create the CSI: the weighted sum of age-standardized, site-specific, relative survival ratios, with weights derived from the distribution of incident cases by sex and primary site from 2006 through 2008. The CSI was calculated for 32 registries for all races, 31 registries for whites, and 12 registries for blacks. Results The survival estimates standardized by age only versus age-, sex-, and site-standardized (CSI) were 64.1% (95% confidence interval [CI], 64.1%–64.2%) and 63.9% (95% CI, 63.8%–63.9%), respectively, for the United States for all races combined. The inter-registry ranges in unstandardized and CSI estimates decreased from 12.3% to 5.0% for whites, and from 5.4% to 3.9% for blacks. We found less inter-registry variation in CSI estimates than in unstandardized all-sites survival estimates, but disparities by race persisted. Conclusions CSIs calculated for different jurisdictions or periods are directly comparable, because they are standardized by age, sex, and primary site. A national CSI could be used to measure temporal progress in meeting public health objectives, such as Healthy People 2030. PMID:28910593

Robust transceiver design for reciprocal M × N interference channel based on statistical linearization approximation

NASA Astrophysics Data System (ADS)

Mayvan, Ali D.; Aghaeinia, Hassan; Kazemi, Mohammad

2017-12-01

This paper focuses on robust transceiver design for throughput enhancement on the interference channel (IC), under imperfect channel state information (CSI). In this paper, two algorithms are proposed to improve the throughput of the multi-input multi-output (MIMO) IC. Each transmitter and receiver has, respectively, M and N antennas and IC operates in a time division duplex mode. In the first proposed algorithm, each transceiver adjusts its filter to maximize the expected value of signal-to-interference-plus-noise ratio (SINR). On the other hand, the second algorithm tries to minimize the variances of the SINRs to hedge against the variability due to CSI error. Taylor expansion is exploited to approximate the effect of CSI imperfection on mean and variance. The proposed robust algorithms utilize the reciprocity of wireless networks to optimize the estimated statistical properties in two different working modes. Monte Carlo simulations are employed to investigate sum rate performance of the proposed algorithms and the advantage of incorporating variation minimization into the transceiver design.

The Mini-Mast CSI testbed: Lessons learned

NASA Technical Reports Server (NTRS)

Tanner, Sharon E.; Belvin, W. Keith; Horta, Lucas G.; Pappa, R. S.

1993-01-01

The Mini-Mast testbed was one of the first large scale Controls-Structure-Interaction (CSI) systems used to evaluate state-of-the-art methodology in flexible structure control. Now that all the testing at Langley Research Center has been completed, a look back is warranted to evaluate the program. This paper describes some of the experiences and technology development studies by NASA, university, and industry investigators. Lessons learned are presented from three categories: the testbed development, control methods, and the operation of a guest investigator program. It is shown how structural safety margins provided a realistic environment to simulate on-orbit CSI research, even though they also reduced the research flexibility afforded to investigators. The limited dynamic coupling between the bending and torsion modes of the cantilevered test article resulted in highly successful SISO and MIMO controllers. However, until accurate models were obtained for the torque wheel actuators, sensors, filters, and the structure itself, most controllers were unstable. Controls research from this testbed should be applicable to cantilevered appendages of future large space structures.

Modulation of precipitation by conditional symmetric instability release

NASA Astrophysics Data System (ADS)

Glinton, Michael R.; Gray, Suzanne L.; Chagnon, Jeffrey M.; Morcrette, Cyril J.

2017-03-01

Although many theoretical and observational studies have investigated the mechanism of conditional symmetric instability (CSI) release and associated it with mesoscale atmospheric phenomena such as frontal precipitation bands, cloud heads in rapidly developing extratropical cyclones and sting jets, its climatology and contribution to precipitation have not been extensively documented. The aim of this paper is to quantify the contribution of CSI release, yielding slantwise convection, to climatological precipitation accumulations for the North Atlantic and western Europe. Case studies reveal that CSI release could be common along cold fronts of mature extratropical cyclones and the North Atlantic storm track is found to be a region with large CSI according to two independent CSI metrics. Correlations of CSI with accumulated precipitation are also large in this region and CSI release is inferred to be occurring about 20% of the total time over depths of over 1 km. We conclude that the inability of current global weather forecast and climate prediction models to represent CSI release (due to insufficient resolution yet lack of subgrid parametrization schemes) may lead to errors in precipitation distributions, particularly in the region of the North Atlantic storm track.

Microbial Community Composition of Tap Water and Biofilms Treated with or without Copper-Silver Ionization.

PubMed

Stüken, Anke; Haverkamp, Thomas H A; Dirven, Hubert A A M; Gilfillan, Gregor D; Leithaug, Magnus; Lund, Vidar

2018-03-20

Copper-silver ionization (CSI) is an in-house water disinfection method primarily installed to eradicate Legionella bacteria from drinking water distribution systems (DWDS). Its effect on the abundance of culturable Legionella and Legionella infections has been documented in several studies. However, the effect of CSI on other bacteria in DWDS is largely unknown. To investigate these effects, we characterized drinking water and biofilm communities in a hospital using CSI, in a neighboring building without CSI, and in treated drinking water at the local water treatment plant. We used 16S rDNA amplicon sequencing and Legionella culturing. The sequencing results revealed three distinct water groups: (1) cold-water samples (no CSI), (2) warm-water samples at the research institute (no CSI), and (3) warm-water samples at the hospital (after CSI; ANOSIM, p < 0.001). Differences between the biofilm communities exposed and not exposed to CSI were less clear (ANOSIM, p = 0.022). No Legionella were cultured, but limited numbers of Legionella sequences were recovered from all 25 water samples (0.2-1.4% relative abundance). The clustering pattern indicated local selection of Legionella types (Kruskal-Wallis, p < 0.001). Furthermore, one unclassified Betaproteobacteria OTU was highly enriched in CSI-treated warm water samples at the hospital (Kruskal-Wallis, p < 0.001).

The Communication Supports Inventory-Children & Youth (CSI-CY), a new instrument based on the ICF-CY.

PubMed

Rowland, Charity; Fried-Oken, Melanie; Bowser, Gayl; Granlund, Mats; Lollar, Donald; Phelps, Randall; Simeonsson, Rune J; Steiner, Sandra A M

2016-09-01

Two studies are presented that evaluated the Communication Supports Inventory-Children & Youth (CSI-CY), an instrument designed to facilitate the development of communication-related educational goals for students with complex communication needs (CCN). The CSI-CY incorporates a code set based on the ICF-CY. The studies were designed to determine the effect of using the CSI-CY on IEP goals for students with CCN and to evaluate consumer satisfaction. In Study 1, sixty-one educators and speech-language pathologists were randomly assigned to either (a) provide a student's current IEP (control group) or (b) complete the CSI-CY prior to preparing a student's next IEP and to submit the new IEP (experimental group). Study 2 was a field test to generate consumer satisfaction data. Study 1 showed that IEP goals submitted by participants in the experimental group referenced CSI-CY-related content significantly more frequently than did those submitted by control participants. Study 2 revealed high satisfaction with the instrument. The code set basis of the CSI-CY extends the common language of the ICF-CY to practical educational use for children with CCN across diagnostic groups. The CSI-CY is well regarded as an instrument to inform the content of communication goals related to CCN. Implications for Rehabilitation The CSI-CY will guide rehabilitation professionals to develop goals for children with complex communication impairments. The CSI-CY is a new instrument that is based on the ICF-CY for documentation of communication goals.

Gamma-ray spectroscopy of 131Sn81 via the (9Be, 8Be γ) reaction

NASA Astrophysics Data System (ADS)

Burcher, Sean; Bey, A.; Jones, K.; Ahn, S. H.; Ayres, A.; Schmitt, K. T.; Allmond, J.; Galindo-Urribari, A.; Radford, D. C.; Liang, J. F.; Neseraja, C. D.; Pain, S. D.; Pittman, S. T.; Smith, M. S.; Stracener, D. W.; Varner, R. L.; Bardayan, D. W.; O'Malley, P. D.; Cizewski, J. A.; Howard, M. E.; Manning, B. M.; Garcia Ruiz, R. F.; Kozub, R. L.; Matos, M.; Padilla-Rodal, E.

2016-09-01

Nuclear data in the region of the doubly-magic nucleus 132Sn82 is useful for benchmarking nuclear structure theories due to the clean single-particle nature of the nuclear wavefunction near the closed shells. At the Holifield Radioactive Ion Beam Facility (HRIBF) neutron-rich beams in the 132Sn82 region were produced via proton-induced fission of a Uranium-Carbide target. The CLARION array of HPGe detectors was coupled with the HyBall array of CsI detectors to allow for particle-gamma coincidence measurements. The gamma-ray de-excitation of the four lowest lying single-neutron states has been observed for the first time via the (9Be,8Be γ) reaction. The excitation energy of these states have been measured to higher precision than was possible with the previous charged particle measurement. This work was supported in part by the U.S. Department of Energy and the National Science Foundation.

Evolutionarily conserved intracellular gate of voltage-dependent sodium channels

NASA Astrophysics Data System (ADS)

Oelstrom, Kevin; Goldschen-Ohm, Marcel P.; Holmgren, Miguel; Chanda, Baron

2014-03-01

Members of the voltage-gated ion channel superfamily (VGIC) regulate ion flux and generate electrical signals in excitable cells by opening and closing pore gates. The location of the gate in voltage-gated sodium channels, a founding member of this superfamily, remains unresolved. Here we explore the chemical modification rates of introduced cysteines along the S6 helix of domain IV in an inactivation-removed background. We find that state-dependent accessibility is demarcated by an S6 hydrophobic residue; substituted cysteines above this site are not modified by charged thiol reagents when the channel is closed. These accessibilities are consistent with those inferred from open- and closed-state structures of prokaryotic sodium channels. Our findings suggest that an intracellular gate composed of a ring of hydrophobic residues is not only responsible for regulating access to the pore of sodium channels, but is also a conserved feature within canonical members of the VGIC superfamily.

A spaceborne optical interferometer: The JPL CSI mission focus

NASA Astrophysics Data System (ADS)

Laskin, R. A.

1989-08-01

The JPL Control Structure Interaction (CSI) program is part of the larger NASA-wide CSI program. Within this larger context, the JPL CSI program will emphasize technology for systems that demand micron or sub-micron level control, so-called Micro-Precision Controlled Structures (u-PCS). The development of such technology will make it practical to fly missions with large optical or large precision antenna systems. In keeping with the focused nature of the desired technology, the JPL approach is to identify a focus mission, develop the focus mission CSI system design to a preliminary level, and then use this design to drive out requirements for CSI technology development in the design and analysis, ground test bed, and flight experiment areas.

Dynamic regulation of mechanosensitive channels: capacitance used to monitor patch tension in real time

NASA Astrophysics Data System (ADS)

Suchyna, Thomas M.; Besch, Steven R.; Sachs, Frederick

2004-03-01

All cells, from bacteria to human, are mechanically sensitive. The most rapid of these membrane protein transducers are mechanosensitive ion channels, ionic pores in the membrane that open and close in response to membrane tension. In specific sensory organs, these channels serve the senses of touch and hearing, and inform the central nervous system about the filling of hollow organs such as the bladder. Non-specialized cells use these channels to report on changes in cell volume and local strain. To preserve dynamic sensitivity, sensory receptors adapt to steady-state stimuli. Here we show that in rat astrocytes, the most abundant cells in the brain, this apparent adaptation to the stimulus is actually an inactivation. We have been able to track the time course of local strain by measuring attofarad changes in membrane capacitance and show that it is not correlated with loss of channel activity. The reduction in current with time is caused by an increased occupancy of low conductance states, and a reduction in the probability of opening, not a relaxation of local stress. The occupancy of these substates depends on the integrity of the cell's cytoplasm. However, while disruption of the cytoskeleton leads to a loss of inactivation, it leaves activation unaffected. The activation process is voltage-insensitive, closely correlated with changes in capacitance, and seems to arise solely from stress in the bilayer. The inactivation rate decreases with depolarization, and kinetic analysis suggests that the process involves multiple cytoplasmic ligands. Surprisingly, multivalent ions such as Gd+3 and Ca+2 that bind to the lipids and affect channel gating, do not affect the strain-induced increase in membrane capacitance; contrary to expectations, membrane elasticity is unchanged.

Blockade by N-3 polyunsaturated fatty acid of the Kv4.3 current stably expressed in Chinese hamster ovary cells

PubMed Central

Singleton, C B; Valenzuela, S M; Walker, B D; Tie, H; Wyse, K R; Bursill, J A; Qiu, M R; Breit, S N; Campbell, T J

1999-01-01

The Kv4.3 gene is believed to encode a large proportion of the transient outward current (Ito), responsible for the early phase of repolarization of the human cardiac action potential. There is evidence that this current is involved in the dispersion of refractoriness which develops during myocardial ischaemia and which predisposes to the development of potentially fatal ventricular tachyarrhythmias. Epidemiological, clinical, animal, and cellular studies indicate that these arrhythmias may be ameliorated in myocardial ischaemia by n-3 polyunsaturated fatty acids (n-3 PUFA) present in fish oils. We describe stable transfection of the Kv4.3 gene into a mammalian cell line (Chinese hamster ovary cells), and using patch clamp techniques have shown that the resulting current closely resembles human Ito. The current is rapidly activating and inactivating, with both processes being well fit by double exponential functions (time constants of 3.8±0.2 and 5.3±0.4 ms for activation and 20.0±1.2 and 96.6±6.7 ms for inactivation at +45 mV at 23°C). Activation and steady state inactivation both show voltage dependence (V1/2 of activation=−6.7±2.5 mV, V1/2 of steady state inactivation=−51.3±0.2 mV at 23°C). Current inactivation and recovery from inactivation are faster at physiologic temperature (37°C) compared to room temperature (23°C). The n-3 PUFA docosahexaenoic acid blocks the Kv4.3 current with an IC50 of 3.6 μmol L−1. Blockade of the transient outward current may be an important mechanism by which n-3 PUFA provide protection against the development of ventricular fibrillation during myocardial ischaemia. PMID:10433502

Efficiency and multifractality analysis of CSI 300 based on multifractal detrending moving average algorithm

NASA Astrophysics Data System (ADS)

Zhou, Weijie; Dang, Yaoguo; Gu, Rongbao

2013-03-01

We apply the multifractal detrending moving average (MFDMA) to investigate and compare the efficiency and multifractality of 5-min high-frequency China Securities Index 300 (CSI 300). The results show that the CSI 300 market becomes closer to weak-form efficiency after the introduction of CSI 300 future. We find that the CSI 300 is featured by multifractality and there are less complexity and risk after the CSI 300 index future was introduced. With the shuffling, surrogating and removing extreme values procedures, we unveil that extreme events and fat-distribution are the main origin of multifractality. Besides, we discuss the knotting phenomena in multifractality, and find that the scaling range and the irregular fluctuations for large scales in the Fq(s) vs s plot can cause a knot.

Characterization of 3×3×10 cm3 CsI Crystals for Nuclear Physics Experiments

NASA Astrophysics Data System (ADS)

Sweany, Sean; Lynch, William; Tsang, Betty; Chajecki, Zbigniew; Brown, Kyle; Morfouace, Pierre; Kuan, Zhu; Crosby, Jacob; Anderson, Corinne; Kodali, Suhas

2017-09-01

The symmetry energy portion of the nuclear equation of state is currently poorly constrained in asymmetric nuclear matter. The momentum dependence of the symmetry energy potential causes a reduction in the nucleon masses causing a splitting between the neutron and proton effective masses. From transport simulations, n/p spectral ratios are shown to be a good observable for studying this effective mass splitting. Arrays of silicon strip detectors backed by scintillator crystals are an effective way of detecting and identifying charged particles over a large range of angles. Recently the HiRA group at the NSCL has finished updating of the HiRA array with 10 cm CsI crystals, HiRA10. The longer CsI crystals allow for higher energy particles to be measured. The doping gradient of thallium along with side and surface treatment of CsI can cause nonuniformity in light output of the crystals, therefore the crystals must characterized before use. For characterization, the crystals were scanned using a collimated Am241 source in a grid pattern of 64 points per crystal. The design of HiRA10 as well as the results of the tests for crystal uniformity will be presented in this talk. This material is based upon work supported by the National Science Foundation under Grant No. PHY 1565546.

Integrated design of the CSI evolutionary structure: A verification of the design methodology

NASA Technical Reports Server (NTRS)

Maghami, Peiman G.; Joshi, S. M.; Elliott, Kenny B.; Walz, J. E.

1993-01-01

One of the main objectives of the Controls-Structures Interaction (CSI) program is to develop and evaluate integrated controls-structures design methodology for flexible space structures. Thus far, integrated design methodologies for a class of flexible spacecraft, which require fine attitude pointing and vibration suppression with no payload articulation, have been extensively investigated. Various integrated design optimization approaches, such as single-objective optimization, and multi-objective optimization, have been implemented with an array of different objectives and constraints involving performance and cost measures such as total mass, actuator mass, steady-state pointing performance, transient performance, control power, and many more. These studies have been performed using an integrated design software tool (CSI-DESIGN CODE) which is under development by the CSI-ADM team at the NASA Langley Research Center. To date, all of these studies, irrespective of the type of integrated optimization posed or objectives and constraints used, have indicated that integrated controls-structures design results in an overall spacecraft design which is considerably superior to designs obtained through a conventional sequential approach. Consequently, it is believed that validation of some of these results through fabrication and testing of a structure which is designed through an integrated design approach is warranted. The objective of this paper is to present and discuss the efforts that have been taken thus far for the validation of the integrated design methodology.

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

Kirimura, Kohtaro, E-mail: kkohtaro@waseda.jp; Watanabe, Shotaro; Kobayashi, Keiichi

Type III polyketide synthases (PKSs) catalyze the formation of pyrone- and resorcinol-types aromatic polyketides. The genomic analysis of the filamentous fungus Aspergillus niger NRRL 328 revealed that this strain has a putative gene (chr-8-2: 2978617–2979847) encoding a type III PKS, although its functions are unknown. In this study, for functional analysis of this putative type III PKS designated as An-CsyA, cloning and heterologous expression of the An-CsyA gene (An-csyA) in Escherichia coli were performed. Recombinant His-tagged An-CsyA was successfully expressed in E. coli BL21 (DE3), purified by Ni{sup 2+}-affinity chromatography, and used for in vitro assay. Tests on the substrate specificity ofmore » the His-tagged An-CsyA with myriad acyl-CoAs as starter substrates and malonyl-CoA as extender substrate showed that His-tagged An-CsyA accepted fatty acyl-CoAs (C2-C14) and produced triketide pyrones (C2-C14), tetraketide pyrones (C2-C10), and pentaketide resorcinols (C10-C14). Furthermore, acetoacetyl-CoA, malonyl-CoA, isobutyryl-CoA, and benzoyl-CoA were also accepted as starter substrates, and both of triketide pyrones and tetraketide pyrones were produced. It is noteworthy that the His-tagged An-CsyA produced polyketides from malonyl-CoA as starter and extender substrates and produced tetraketide pyrones from short-chain fatty acyl-CoAs as starter substrates. Therefore, this is the first report showing the functional properties of An-CsyA different from those of other fungal type III PKSs. -- Highlights: •Type III PKS from Aspergillus niger NRRL 328, An-CsyA, was cloned and characterized. •An-CsyA produced triketide pyrones, tetraketide pyrones and pentaketide resorcinols. •Functional properties of An-CsyA differs from those of other fungal type III PKSs.« less

Pedestrians injured by automobiles: risk factors for cervical spine injuries.

PubMed

Yanar, Hakan; Demetriades, Demetrios; Hadjizacharia, Pantelis; Hatzizacharia, Pantelis; Nomoto, Shirley; Salim, Ali; Inaba, Kenji; Rhee, Peter; Chan, Linda S

2007-12-01

Diagnosis of cervical spine injuries (CSI) in multitrauma patients, especially in the presence of head trauma, can be difficult. Identification of risk factors associated with CSI can help avoid missed or delayed diagnosis. Trauma registry study of pedestrian injuries caused by being hit by an automobile. Data abstracted for each patient included age, gender, Glasgow Coma Score on admission, Injury Severity Score, Abbreviated Injury Scale (AIS) for each body area, level of cervical spine injuries, and associated injuries. The incidence of spine injuries was derived for 4 age groups (14 years and younger, 15 to 55 years, 56 to 65 years, and older than 65 years). Logistic regression analysis was performed to identify risk factors associated with CSI. There were 8,401 pedestrian injuries caused by automobiles, and 178 patients (2.1%) had CSI. Incidence of CSI increased with age (0.3% in the age group 14 years and younger, 2.2% in the group 15 to 55 years, 3.7% in the group 56 to 65 years, and 4.4% in the group older than 65 years). Using the youngest age group (14 years and younger) as reference, relative risk of CSI in the other groups was 7.0, 12.1, and 14.2, respectively (p < 0.0001). Patients with severe head trauma (AIS > 3) were significantly more likely to have CSI than patients with less severe head injuries (AIS 3), severe chest trauma (AIS > 3), pelvic fracture, and femur fracture as independent risk factors for CSI. Incidence of CSI after injuries to pedestrians hit by automobiles increases with age and severity of head trauma. Age, severe head trauma, severe chest trauma, pelvic fracture, and femur fractures are independent predictors of CSI.

Whole Neuraxis Irradiation to Address Central Nervous System Relapse in High-Risk Neuroblastoma

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

Croog, Victoria J., E-mail: vcroog@sibley.or; Kramer, Kim; Cheung, Nai-Kong V.

Background: As systemic control of high-risk neuroblastoma (NB) has improved, relapse in the central nervous system (CNS) is an increasingly recognized entity that carries a grim prognosis. This study describes the use of craniospinal irradiation (CSI) for CNS relapse and compares outcomes to patients who received focal radiotherapy (RT). Methods: A retrospective query identified 29 children with NB treated at Memorial Sloan-Kettering Cancer Center since 1987 who received RT for CNS relapse. At CNS relapse, 16 patients received CSI (median dose, 2160cGy), and 13 received focal RT. Of those who underwent CSI, 14 (88%) received intra-Ommaya (IO) radioimmunotherapy (RIT); onemore » patient in the non-CSI cohort received IO-RIT. Results: Patient characteristics were similar between the groups. Time to CNS relapse was 20 and 17 months for the CSI and non-CSI cohorts, respectively. At a median follow-up of 28 months, 12 patients (75%) in the CSI group are alive without CNS disease, including two patients with isolated skeletal relapse. Another patient is alive without disease after a brain relapse was retreated with RT. Three patients died-one with no NB at autopsy, one of CNS disease, and one of systemic disease. The two patients who died of NB did not receive IO-RIT. All 13 patients in the non-CSI cohort died at a median of 8.8 months. Conclusions: Low-dose CSI together with IO-RIT provides durable CNS remissions and improved survival compared with focal RT and conventional therapies. Further evaluation of long-term NB survivors after CSI is warranted to determine the treatment consequences for this cohort.« less

Stress corrosion cracking of Zircaloys in unirradiated and irradiated CsI

NASA Astrophysics Data System (ADS)

Cox, B.; Surette, B. A.; Wood, J. C.

1986-03-01

Unirradiated split-ring specimens of Zircaloy fuel cladding, coated with CsI, cracked when stressed at elevated temperatures. The specimens have been reexamined fractographically and metallographically in order to confirm that the cause of cracking was stress corrosion (SCC) and not delayed hydride cracking (DHC). Further specimens have been cracked at 350°C by a solution of CsI in a fused mixture of nitrates of rubidium, cesium, strontium and barium, by a similar mechanism. CsI dissolved in a fused molybdate melt was not stable at 400°C, and rapidly evolved iodine, leaving a melt that was incapable of causing SCC. Irradiation of stressed split-ring specimens of Zircaloy fuel cladding in a γ-irradiator of 10 6 R/h and in the U-5 loop in the NRU reactor at an estimated 10 9 R/h caused SCC when the specimens were packed in dry CsI powder. Care had to be taken to dry the CsI, otherwise cracking occurred by a DHC mechanism from hydrogen absorbed from residual moisture in the CsI. Fractography showed that the crack surfaces obtained with dry CsI were typical of iodine-induced SCC rather than cesium-induced metal vapour embrittlement. Thus, if a transport process is provided for the iodide to obtain access to the zirconium surface, CsI is capable of causing SCC of Zircaloy. This transport process might be ionic diffusion in a fission product oxide melt in the fuel-clad gap, however, radiolysis of CsI to form a volatile iodine species in a radiation field is the more probable explanation of PCI failures.

Characterization of silicon heterojunctions for solar cells

PubMed Central

2011-01-01

Conductive-probe atomic force microscopy (CP-AFM) measurements reveal the existence of a conductive channel at the interface between p-type hydrogenated amorphous silicon (a-Si:H) and n-type crystalline silicon (c-Si) as well as at the interface between n-type a-Si:H and p-type c-Si. This is in good agreement with planar conductance measurements that show a large interface conductance. It is demonstrated that these features are related to the existence of a strong inversion layer of holes at the c-Si surface of (p) a-Si:H/(n) c-Si structures, and to a strong inversion layer of electrons at the c-Si surface of (n) a-Si:H/(p) c-Si heterojunctions. These are intimately related to the band offsets, which allows us to determine these parameters with good precision. PMID:21711658

Systematical Evaluation of Mechanically Strong 3D Printed Diluted magnesium Doping Wollastonite Scaffolds on Osteogenic Capacity in Rabbit Calvarial Defects

PubMed Central

Sun, Miao; Liu, An; Shao, Huifeng; Yang, Xianyan; Ma, Chiyuan; Yan, Shigui; Liu, Yanming; He, Yong; Gou, Zhongru

2016-01-01

Wollastonite (CaSiO3; CSi) ceramic is a promising bioactive material for bone defect repair due to slightly fast degradation of its porous constructs in vivo. In our previous strategy some key features of CSi ceramic have been significantly improved by dilute magnesium doping for regulating mechanical properties and biodegradation. Here we demonstrate that 6 ~ 14% of Ca substituted by Mg in CSi (CSi-Mgx, x = 6, 10, 14) can enhance the mechanical strength (>40 MPa) but not compromise biological performances of the 3D printed porous scaffolds with open porosity of 60‒63%. The in vitro cell culture tests in vitro indicated that the dilute Mg doping into CSi was beneficial for ALP activity and high expression of osteogenic marker genes of MC3T3-E1 cells in the scaffolds. A good bone tissue regeneration response and elastoplastic response in mechanical strength in vivo were determined after implantation in rabbit calvarial defects for 6‒12 weeks. Particularly, the CSi-Mg10 and CSi-Mg14 scaffolds could enhance new bone regeneration with a significant increase of newly formed bone tissue (18 ~ 22%) compared to the pure CSi (~14%) at 12 weeks post-implantation. It is reasonable to consider that, therefore, such CSi-Mgx scaffolds possessing excellent strength and reasonable degradability are promising for bone reconstruction in thin-wall bone defects. PMID:27658481

CSI 3.0: a web server for identifying secondary and super-secondary structure in proteins using NMR chemical shifts

PubMed Central

Hafsa, Noor E.; Arndt, David; Wishart, David S.

2015-01-01

The Chemical Shift Index or CSI 3.0 (http://csi3.wishartlab.com) is a web server designed to accurately identify the location of secondary and super-secondary structures in protein chains using only nuclear magnetic resonance (NMR) backbone chemical shifts and their corresponding protein sequence data. Unlike earlier versions of CSI, which only identified three types of secondary structure (helix, β-strand and coil), CSI 3.0 now identifies total of 11 types of secondary and super-secondary structures, including helices, β-strands, coil regions, five common β-turns (type I, II, I′, II′ and VIII), β hairpins as well as interior and edge β-strands. CSI 3.0 accepts experimental NMR chemical shift data in multiple formats (NMR Star 2.1, NMR Star 3.1 and SHIFTY) and generates colorful CSI plots (bar graphs) and secondary/super-secondary structure assignments. The output can be readily used as constraints for structure determination and refinement or the images may be used for presentations and publications. CSI 3.0 uses a pipeline of several well-tested, previously published programs to identify the secondary and super-secondary structures in protein chains. Comparisons with secondary and super-secondary structure assignments made via standard coordinate analysis programs such as DSSP, STRIDE and VADAR on high-resolution protein structures solved by X-ray and NMR show >90% agreement between those made with CSI 3.0. PMID:25979265

Use of the Central Sensitization Inventory (CSI) as a treatment outcome measure for patients with chronic spinal pain disorder in a functional restoration program.

PubMed

Neblett, Randy; Hartzell, Meredith M; Williams, Mark; Bevers, Kelley R; Mayer, Tom G; Gatchel, Robert J

2017-12-01

The Central Sensitization Inventory (CSI) is a valid and reliable patient-reported instrument designed to identify patients whose presenting symptoms may be related to central sensitization (CS). Part A of the CSI measures a full array of 25 somatic and emotional symptoms associated with CS, and Part B asks if patients have previously been diagnosed with one or more specific central sensitivity syndromes (CSSs) and related disorders. The CSI has previously been validated in a group of patients with chronic pain who were screened by a trained psychiatrist for specific CSS diagnoses. It is currently unknown if the CSI can be a useful treatment-outcome assessment tool for patients with chronic spinal pain disorder (CSPD) who are not screened for comorbid CSSs. It is known, however, that previous studies have identified CS-related symptoms, and comorbid CSSs, in subsets of patients with CSPDs. Studies have also shown that CS-related symptoms can be influenced by cognitive and psychosocial factors, including abuse history in both childhood and adulthood, sleep disturbance, catastrophic and fear-avoidant cognitions, and symptoms of depression and anxiety. This study aimed to evaluate CSI scores, and their associations with other clinically relevant psychosocial variables, in a cohort of patients with CSPD who entered and completed a functional restoration program. A retrospective study of prospectively collected data from a cohort study of patients with CSPD, who completed the CSI at admission to, and discharge from, an interdisciplinary function restoration program (FRP) was carried out. A cohort of 763 patients with CSPD comprised the study sample. Clinical interviews evaluated mood disorders and abuse history. A series of self-reported measures evaluated comorbid psychosocial symptoms, including pain intensity, pain-related anxiety, depressive symptoms, somatization symptoms, perceived disability, and sleep disturbance, at FRP admission and discharge. Patients were grouped into five severity level groups, from mild to extreme, based on total CSI scores, at FRP admission, and then again at discharge. The FRP included a quantitatively directed and medically supervised exercise process, as well as a multimodal psychosocial disability management component. The CSI severity groups were strongly associated with Major Depressive Disorder and previous abuse history (p<.01), which are known risk factors for CS-related symptoms and diagnoses. The CSI scores were also strongly associated with patient-reported CSS diagnoses on CSI Part B. The percentage of patients who reported a comorbid CSS diagnosis increased in each higher CSI-severity group, from 11% in the Subclinical group, to 56% in the Extreme group. The CSI severity groups were significantly related to other CS-related patient-reported symptoms, including pain intensity, pain-related anxiety, depressive symptoms, somatization symptoms, perceived disability, and sleep disturbance (p's<.001). The CSI scores, along with all other psychosocial measures, decreased at treatment discharge. In the present study, admission CSI scores were highly associated with previous CSS diagnoses, CS-related symptoms, and clinically relevant patient-reported psychosocial variables. All psychosocial variables, as well as scores on the CSI, were significantly improved at FRP discharge. The CSI may have important clinical utility, as a screener and as a treatment outcome measure, for patients with CSPD participating in an interdisciplinary FRP. Copyright © 2017 Elsevier Inc. All rights reserved.

Fast CsI-phoswich detector

DOEpatents

Langenbrunner, James R.

1996-01-01

An improved phoswich radiation detector used pure CsI crystal and a fast plastic scintillator and a single photomultiplier tube. The plastic is arranged to receive incident radiation, and that which passed through then strikes the CsI crystal. Scintillation light from both the plastic and CsI crystal are applied to the photomultiplier tube, with the light from the plastic passing through the crystal without absorption therein. Electronics are provided for analyzing the output of the photomultiplier tube to discriminate responses due to the plastic and the CsI crystal, through short gate and long gate integration, to produce results which are indicative of the characteristics of the different types of incident radiation, even in the presence of large amounts of radiation. The phoswich detector has excellent timing resolution. The scintillators of the CsI- phoswich were chosen for their fast risetimes, of about 3 ns for NE102A, and 30 ns for the pure CsI.

Fast CsI-phoswich detector

DOEpatents

Langenbrunner, J.R.

1996-05-07

An improved phoswich radiation detector used pure CsI crystal and a fast plastic scintillator and a single photomultiplier tube. The plastic is arranged to receive incident radiation, and that which passed through then strikes the CsI crystal. Scintillation light from both the plastic and CsI crystal are applied to the photomultiplier tube, with the light from the plastic passing through the crystal without absorption therein. Electronics are provided for analyzing the output of the photomultiplier tube to discriminate responses due to the plastic and the CsI crystal, through short gate and long gate integration, to produce results which are indicative of the characteristics of the different types of incident radiation, even in the presence of large amounts of radiation. The phoswich detector has excellent timing resolution. The scintillators of the CsI- phoswich were chosen for their fast risetimes, of about 3 ns for NE102A, and 30 ns for the pure CsI. 5 figs.

Ion-binding properties of a K+ channel selectivity filter in different conformations.

PubMed

Liu, Shian; Focke, Paul J; Matulef, Kimberly; Bian, Xuelin; Moënne-Loccoz, Pierre; Valiyaveetil, Francis I; Lockless, Steve W

2015-12-08

K(+) channels are membrane proteins that selectively conduct K(+) ions across lipid bilayers. Many voltage-gated K(+) (KV) channels contain two gates, one at the bundle crossing on the intracellular side of the membrane and another in the selectivity filter. The gate at the bundle crossing is responsible for channel opening in response to a voltage stimulus, whereas the gate at the selectivity filter is responsible for C-type inactivation. Together, these regions determine when the channel conducts ions. The K(+) channel from Streptomyces lividians (KcsA) undergoes an inactivation process that is functionally similar to KV channels, which has led to its use as a practical system to study inactivation. Crystal structures of KcsA channels with an open intracellular gate revealed a selectivity filter in a constricted conformation similar to the structure observed in closed KcsA containing only Na(+) or low [K(+)]. However, recent work using a semisynthetic channel that is unable to adopt a constricted filter but inactivates like WT channels challenges this idea. In this study, we measured the equilibrium ion-binding properties of channels with conductive, inactivated, and constricted filters using isothermal titration calorimetry (ITC). EPR spectroscopy was used to determine the state of the intracellular gate of the channel, which we found can depend on the presence or absence of a lipid bilayer. Overall, we discovered that K(+) ion binding to channels with an inactivated or conductive selectivity filter is different from K(+) ion binding to channels with a constricted filter, suggesting that the structures of these channels are different.

CSI 3.0: a web server for identifying secondary and super-secondary structure in proteins using NMR chemical shifts.

PubMed

Hafsa, Noor E; Arndt, David; Wishart, David S

2015-07-01

The Chemical Shift Index or CSI 3.0 (http://csi3.wishartlab.com) is a web server designed to accurately identify the location of secondary and super-secondary structures in protein chains using only nuclear magnetic resonance (NMR) backbone chemical shifts and their corresponding protein sequence data. Unlike earlier versions of CSI, which only identified three types of secondary structure (helix, β-strand and coil), CSI 3.0 now identifies total of 11 types of secondary and super-secondary structures, including helices, β-strands, coil regions, five common β-turns (type I, II, I', II' and VIII), β hairpins as well as interior and edge β-strands. CSI 3.0 accepts experimental NMR chemical shift data in multiple formats (NMR Star 2.1, NMR Star 3.1 and SHIFTY) and generates colorful CSI plots (bar graphs) and secondary/super-secondary structure assignments. The output can be readily used as constraints for structure determination and refinement or the images may be used for presentations and publications. CSI 3.0 uses a pipeline of several well-tested, previously published programs to identify the secondary and super-secondary structures in protein chains. Comparisons with secondary and super-secondary structure assignments made via standard coordinate analysis programs such as DSSP, STRIDE and VADAR on high-resolution protein structures solved by X-ray and NMR show >90% agreement between those made with CSI 3.0. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

Electric machine and current source inverter drive system

DOEpatents

Hsu, John S

2014-06-24

A drive system includes an electric machine and a current source inverter (CSI). This integration of an electric machine and an inverter uses the machine's field excitation coil for not only flux generation in the machine but also for the CSI inductor. This integration of the two technologies, namely the U machine motor and the CSI, opens a new chapter for the component function integration instead of the traditional integration by simply placing separate machine and inverter components in the same housing. Elimination of the CSI inductor adds to the CSI volumetric reduction of the capacitors and the elimination of PMs for the motor further improve the drive system cost, weight, and volume.

Characteristics of cesium iodide for use as a particle discriminator for high energy cosmic rays

NASA Technical Reports Server (NTRS)

Crannell, C. J.; Kurz, R. J.; Viehmann, W.

1973-01-01

The possible use of CsI to discriminate between high energy cosmic ray electrons and interacting protons has been investigated. The pulse-shape properties as a function of ionization density, temperature, and spectral response are presented for thallium-activated CsI and as a function of ionization density for sodium-activated CsI. The results are based on previously published data and on corroborative measurements from the present work. Experimental results on the response of CsI to electron-induced electromagnetic cascades and to interacting hadrons are described. Bibliographies of publications dealing with the properties of CsI and with pulse-shape discrimination techniques are presented.

Effect of Common Drinking Water Disinfectants, Chlorine and Heat, on Free Legionella and Amoebae-Associated Legionella.

PubMed

Cervero-Aragó, Sílvia; Rodríguez-Martínez, Sarah; Puertas-Bennasar, Antoni; Araujo, Rosa M

2015-01-01

Chlorine and thermal treatments are the most commonly used procedures to control and prevent Legionella proliferation in drinking water systems of large buildings. However, cases of legionellosis still occur in facilities with treated water. The purpose of this work was to model the effect of temperature and free chlorine applied in similar exposure conditions as in drinking water systems on five Legionella spp. strains and two amoebal strains of the genera Acanthamoeba. Inactivation models obtained were used to determine the effectiveness of the treatments applied which resulted more effective against Legionella than Acanthamoeba, especially those in cystic stages. Furthermore, to determine the influence of the relationship between L. pneumophila and Acanthamoeba spp. on the treatment effectiveness, inactivation models of the bacteria-associated amoeba were also constructed and compared to the models obtained for the free living bacteria state. The Legionella-amoeba association did not change the inactivation models, but it reduced the effectiveness of the treatments applied. Remarkably, at the lowest free chlorine concentration, 0.5 mg L-1, as well as at the lowest temperatures, 50°C and 55°C, the influence of the Legionella-amoeba associate state was the strongest in reducing the effectiveness of the treatments compared to the free Legionella state. Therefore, the association established between L. pneumophila and amoebae in the water systems indicate an increased health risk in proximal areas of the system (close to the tap) where lower free chlorine concentrations and lower temperatures are commonly observed.

Pressure- and heat-induced inactivation of butyrylcholinesterase: evidence for multiple intermediates and the remnant inactivation process.

PubMed Central

Weingand-Ziade, A; Ribes, F; Renault, F; Masson, P

2001-01-01

The inactivation process of native (N) human butyrylcholinesterase (BuChE) by pressure and/or heat was found to be multi-step. It led to irreversible formation of an active intermediate (I) state and a denatured state. This series-inactivation process was described by expanding the Lumry-Eyring [Lumry, R. and Eyring, H. (1954) J. Phys. Chem. 58, 110-120] model. The intermediate state (I) was found to have a K(m) identical with that of the native state and a turnover rate (k(cat)) twofold higher than that of the native state with butyrylthiocholine as the substrate. The increased catalytic efficiency (k(cat)/K(m)) of I can be explained by a conformational change in the active-site gorge and/or restructuring of the water-molecule network in the active-site pocket, making the catalytic steps faster. However, a pressure/heat-induced covalent modification of native BuChE, affecting the catalytic machinery, cannot be ruled out. The inactivation process of BuChE induced by the combined action of pressure and heat was found to continue after interruption of pressure/temperature treatment. This secondary inactivation process was termed 'remnant inactivation'. We hypothesized that N and I were in equilibrium with populated metastable N' and I' states. The N' and I' states can either return to the active forms, N and I, or develop into inactive forms, N(')(in) and I(')(in). Both active N' and I' intermediate states displayed different rates of remnant inactivation depending on the pressure and temperature pretreatments and on the storage temperature. A first-order deactivation model describing the kinetics of the remnant inactivation of BuChE is proposed. PMID:11368776

Quantifying the effect of investors' attention on stock market.

PubMed

Yang, Zhen-Hua; Liu, Jian-Guo; Yu, Chang-Rui; Han, Jing-Ti

2017-01-01

The investors' attention has been extensively used to predict the stock market. Different from existing proxies of the investors' attention, such as the Google trends, Baidu index (BI), we argue the collective attention from the stock trading platforms could reflect the investors' attention more closely. By calculated the increments of the attention volume for each stock (IAVS) from the stock trading platforms, we investigate the effect of investors' attention measured by the IAVS on the movement of the stock market. The experimental results for Chinese Securities Index 100 (CSI100) show that the BI is significantly correlated with the returns of CSI100 at 1% significance level only in 2014. However, it should be emphasized that the correlation of the new proposed measure, namely IAVS, is significantly at 1% significance level in 2014 and 2015. It shows that the effect of the measure IAVS on the movement of the stock market is more stable and significant than BI. This study yields important invest implications and better understanding of collective investors' attention.

Quantifying the effect of investors’ attention on stock market

PubMed Central

Yang, Zhen-Hua; Liu, Jian-Guo; Yu, Chang-Rui; Han, Jing-Ti

2017-01-01

The investors’ attention has been extensively used to predict the stock market. Different from existing proxies of the investors’ attention, such as the Google trends, Baidu index (BI), we argue the collective attention from the stock trading platforms could reflect the investors’ attention more closely. By calculated the increments of the attention volume for each stock (IAVS) from the stock trading platforms, we investigate the effect of investors’ attention measured by the IAVS on the movement of the stock market. The experimental results for Chinese Securities Index 100 (CSI100) show that the BI is significantly correlated with the returns of CSI100 at 1% significance level only in 2014. However, it should be emphasized that the correlation of the new proposed measure, namely IAVS, is significantly at 1% significance level in 2014 and 2015. It shows that the effect of the measure IAVS on the movement of the stock market is more stable and significant than BI. This study yields important invest implications and better understanding of collective investors’ attention. PMID:28542216

The Collaborating States Initiative (CSI) Recommended Process for Developing State Policies and Guidelines to Support Social and Emotional Learning

ERIC Educational Resources Information Center

Dusenbury, Linda; Yoder, Nick

2017-01-01

In the work of the authors with states over the years, they have observed that most follow a similar process when they develop policies or guidelines to support statewide implementation of social and emotional learning (SEL), such as establishing learning goals or standards for student social and emotional competencies, or providing guidance to…

Molecular cloning and characterization of Siamese crocodile (Crocodylus siamensis) copper, zinc superoxide dismutase (CSI-Cu,Zn-SOD) gene.

PubMed

Sujiwattanarat, Penporn; Pongsanarakul, Parinya; Temsiripong, Yosapong; Temsiripong, Theeranan; Thawornkuno, Charin; Uno, Yoshinobu; Unajak, Sasimanas; Matsuda, Yoichi; Choowongkomon, Kiattawee; Srikulnath, Kornsorn

2016-01-01

Superoxide dismutase (SOD, EC 1.15.1.1) is an antioxidant enzyme found in all living cells. It regulates oxidative stress by breaking down superoxide radicals to oxygen and hydrogen peroxide. A gene coding for Cu,Zn-SOD was cloned and characterized from Siamese crocodile (Crocodylus siamensis; CSI). The full-length expressed sequence tag (EST) of this Cu,Zn-SOD gene (designated as CSI-Cu,Zn-SOD) contained 462bp encoding a protein of 154 amino acids without signal peptides, indicated as intracellular CSI-Cu,Zn-SOD. This agreed with the results from the phylogenetic tree, which indicated that CSI-Cu,Zn-SOD belonged to the intracellular Cu,Zn-SOD. Chromosomal location determined that the CSI-Cu,Zn-SOD was localized to the proximal region of the Siamese crocodile chromosome 1p. Several highly conserved motifs, two conserved signature sequences (GFHVHEFGDNT and GNAGGRLACGVI), and conserved amino acid residues for binding copper and zinc (His(47), His(49), His(64), His(72), His(81), Asp(84), and His(120)) were also identified in CSI-Cu,Zn-SOD. Real-time PCR analysis showed that CSI-Cu,Zn-SOD mRNA was expressed in all the tissues examined (liver, pancreas, lung, kidney, heart, and whole blood), which suggests a constitutively expressed gene in these tissues. Expression of the gene in Escherichia coli cells followed by purification yielded a recombinant CSI-Cu,Zn-SOD, with Km and Vmax values of 6.075mM xanthine and 1.4×10(-3)mmolmin(-1)mg(-1), respectively. This Vmax value was 40 times lower than native Cu,Zn-SOD (56×10(-3)mmolmin(-1)mg(-1)), extracted from crocodile erythrocytes. This suggests that cofactors, protein folding properties, or post-translational modifications were lost during the protein purification process, leading to a reduction in the rate of enzyme activity in bacterial expression of CSI-Cu,Zn-SOD. Copyright © 2015 Elsevier Inc. All rights reserved.

Filtered gradient reconstruction algorithm for compressive spectral imaging

NASA Astrophysics Data System (ADS)

Mejia, Yuri; Arguello, Henry

2017-04-01

Compressive sensing matrices are traditionally based on random Gaussian and Bernoulli entries. Nevertheless, they are subject to physical constraints, and their structure unusually follows a dense matrix distribution, such as the case of the matrix related to compressive spectral imaging (CSI). The CSI matrix represents the integration of coded and shifted versions of the spectral bands. A spectral image can be recovered from CSI measurements by using iterative algorithms for linear inverse problems that minimize an objective function including a quadratic error term combined with a sparsity regularization term. However, current algorithms are slow because they do not exploit the structure and sparse characteristics of the CSI matrices. A gradient-based CSI reconstruction algorithm, which introduces a filtering step in each iteration of a conventional CSI reconstruction algorithm that yields improved image quality, is proposed. Motivated by the structure of the CSI matrix, Φ, this algorithm modifies the iterative solution such that it is forced to converge to a filtered version of the residual ΦTy, where y is the compressive measurement vector. We show that the filtered-based algorithm converges to better quality performance results than the unfiltered version. Simulation results highlight the relative performance gain over the existing iterative algorithms.

Experiment and simulation for CSI: What are the missing links?

NASA Technical Reports Server (NTRS)

Belvin, W. Keith; Park, K. C.

1989-01-01

Viewgraphs on experiment and simulation for control structure interaction (CSI) are presented. Topics covered include: control structure interaction; typical control/structure interaction system; CSI problem classification; actuator/sensor models; modeling uncertainty; noise models; real-time computations; and discrete versus continuous.

Commercial Generic Bioprocessing Apparatus Science Insert - 03

NASA Technical Reports Server (NTRS)

Moreno, Nancy; Stodieck, Louis; Cushing, Paula; Stowe, Mark; Hamilton, Mary Ann; Werner, Ken

2008-01-01

Commercial Generic Bioprocessing Apparatus Science Insert - 03 (CSI-03) is the third set of investigations in the CSI program series. The CSI program provides the K-12 community opportunities to utilize the unique microgravity environment of the International Space Station as part of the regular classroom to encourage learning and interest in science, technology, engineering and math. CSI-03 will examine the complete life cycle of the painted lady butterfly and the ability of an orb weaving spider to spin a web, eat and remain healthy in space.

Role of the pH in state-dependent blockade of hERG currents

NASA Astrophysics Data System (ADS)

Wang, Yibo; Guo, Jiqing; Perissinotti, Laura L.; Lees-Miller, James; Teng, Guoqi; Durdagi, Serdar; Duff, Henry J.; Noskov, Sergei Yu.

2016-10-01

Mutations that reduce inactivation of the voltage-gated Kv11.1 potassium channel (hERG) reduce binding for a number of blockers. State specific block of the inactivated state of hERG block may increase risks of drug-induced Torsade de pointes. In this study, molecular simulations of dofetilide binding to the previously developed and experimentally validated models of the hERG channel in open and open-inactivated states were combined with voltage-clamp experiments to unravel the mechanism(s) of state-dependent blockade. The computations of the free energy profiles associated with the drug block to its binding pocket in the intra-cavitary site display startling differences in the open and open-inactivated states of the channel. It was also found that drug ionization may play a crucial role in preferential targeting to the open-inactivated state of the pore domain. pH-dependent hERG blockade by dofetilie was studied with patch-clamp recordings. The results show that low pH increases the extent and speed of drug-induced block. Both experimental and computational findings indicate that binding to the open-inactivated state is of key importance to our understanding of the dofetilide’s mode of action.

III-V/Si Tandem Cells Utilizing Interdigitated Back Contact Si Cells and Varying Terminal Configurations: Preprint

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

Schnabel, Manuel; Klein, Talysa R.; Jain, Nikhil

Solar cells made from bulk crystalline silicon (c-Si) dominate the market, but laboratory efficiencies have stagnated because the current record efficiency of 26.3% is already very close to the theoretical limit of 29.4% for a single-junction c-Si cell. In order to substantially boost the efficiency of Si solar cells we have been developing stacked III-V/Si tandem cells, recently attaining efficiencies above 32% in four-terminal configuration. In this contribution, we use state-of-the-art III-V cells coupled with equivalent circuit simulations to compare four-terminal (4T) to three- and two-terminal (3T, 2T) operation. Equivalent circuit simulations are used to show that tandem cells canmore » be operated just as efficiently using three terminals as with four terminals. However, care must be taken not to overestimate 3T efficiency, as the two circuits used to extract current interact, and a method is described to accurately determine this efficiency. Experimentally, a 4T GaInP/Si tandem cell utilizing an interdigitated back contact cell is shown, exhibiting a 4T efficiency of 31.5% and a 2T efficiency of 28.1%. In 3T configuration, it is used to verify the finding from simulation that 3T efficiency is overestimated when interactions between the two circuits are neglected. Considering these, a 3T efficiency approaching the 4T efficiency is found, showing that 3T operation is efficient, and an outlook on fully integrated high-efficiency 3T and 2T tandem cells is given.« less

Central Sensitization Inventory as a Predictor of Worse Quality of Life Measures and Increased Length of Stay Following Spinal Fusion.

PubMed

Bennett, E Emily; Walsh, Kevin M; Thompson, Nicolas R; Krishnaney, Ajit A

2017-08-01

Central sensitization is abnormal and intense enhancement of pain mechanism by the central nervous system. Patients with central sensitization may be at higher risk of poor outcomes after spinal fusion. The Central Sensitivity Inventory (CSI) was developed to identify and quantify key symptoms related to central sensitization. In 664 patients who underwent thoracic and/or lumbar fusion, we evaluated retrospectively pretreatment CSI as a predictor of postoperative quality of life measures, length of stay, and discharge status. Preoperative Pain Disability Questionnaire scores, Patient Health Questionnaire-9 scores, and EuroQol-5 Dimensions index scores were significantly worse in patients with preoperative CSI ≥40 compared with patients with preoperative CSI <40 (P < 0.0001 for all). After adjusting for demographic variables, operation duration, and preoperative health status, preoperative CSI was significantly associated with higher postoperative Pain Disability Questionnaire total score (unadjusted P < 0.001, adjusted P = 0.009), higher postoperative Patient Health Questionnaire-9 score (unadjusted P < 0.001, adjusted P = 0.001), and lower postoperative EuroQol-5 Dimensions index (unadjusted P < 0.001, adjusted P = 0.001). For each 10-unit increase in CSI, average length of stay increased by 6.4% (95% confidence interval 0.4%-12.6%, P = 0.035). The odds of being discharged home after adjusting for confounders was not statistically related to preoperative CSI (P = 0.0709). Preoperative CSI was associated with worse quality of life outcomes and increased length of stay after spinal fusions. CSI may be an additional measure in evaluating patients preoperatively to better predict successful spinal fusion outcomes. Copyright © 2017 Elsevier Inc. All rights reserved.

Unstable cervical spine fracture after penetrating neck injury: a rare entity in an analysis of 1,069 patients.

PubMed

Lustenberger, Thomas; Talving, Peep; Lam, Lydia; Kobayashi, Leslie; Inaba, Kenji; Plurad, David; Branco, Bernardino C; Demetriades, Demetrios

2011-04-01

The value of cervical spine immobilization after penetrating trauma to the neck is the subject of lively debate. The purpose of this study was to review the epidemiology of unstable cervical spine injuries (CSI) after penetrating neck trauma in a large cohort of patients. This is a retrospective analysis of patients admitted with penetrating neck injuries to a Level I trauma center from January 1996 through December 2008. A penetrating neck injury was defined as a gunshot wound (GSW) or stab wound (SW) between the clavicles and the base of the skull. Univariate and multivariate analyses were performed to investigate associations between injury mechanisms, the presence of CSI instability, and mortality. Risk factors independently associated with the presence of a CSI were identified. A total of 1,069 patients met inclusion criteria, of which 463 patients (43.3%) and 606 patients (56.7%) were sustaining GSW and SW, respectively. Overall, 65 patients (6.1%) were diagnosed with a CSI with a significantly higher incidence after GSWs compared with SWs (12.1% vs. 1.5%; p < 0.001). In four patients (0.4%), the CSI was considered unstable, all of them following GSW. All patients with unstable CSI had obvious neurologic deficits or altered mental status at the time of admission. Risk factors independently associated with the presence of a CSI were GSW to the neck and a Glasgow Coma Scale score ≤8 on admission (R = 0.16). The overall incidence of unstable CSI after penetrating trauma to the neck is exceedingly low at 0.4%. Following GSW to the neck, an unstable CSI was noted in <1% of patients. After cervical SW, however, no spinal instability was noted precluding the need for spinal precautions in these instances.

Feasibility study of an orbiting laboratory for testing CSI technology

NASA Technical Reports Server (NTRS)

Bicos, Andrew S.; Loboda, Gregory G.

1993-01-01

A concept for an orbiting laboratory for testing Controls-Structures Integration (CSI) technology is described. The CSI-Star concept reflects a lower cost, higher risk approach. The concept supports demonstration and validation testing for critical CSI technologies at a cost of $20M to $26M with a 1-year reliability of approximately 0.9. The Ball Aerospace QuickStar bus is the carrier for the CSI test article. QuickStar is launched as a secondary payload on the McDonnell Douglas Delta 2. The QuickStar/Delta 2 approach is flight proven. The CSI test article is a 20 foot, 1 Hz, truss beam which is deployed from the QuickStar bus. The test article is well instrumented for quality system identification. The laboratory provides three layers of active control consisting of global vibration suppression along the truss beam, vibration isolation between the beam and instrument platforms, and vibration compensation through the use of gimbaled platforms which point lasers relative to optical sensor targets. The configuration simulates the dynamics of multi-instrument science platforms such as those of the Earth Observation System (EOS) while maintaining strong ties to astrophysics missions such as the Optical Interferometer. Uplink/downlink services and a reprogrammable computer provide flexibility for long-term investigations by members of the CSI community (NASA, DoD, academia, and industry). CSI-Star fills the gap between short-term experiments, which have been conducted primarily on the Shuttle, and future science missions which require the technology. The on-orbit maturity of CSI technology must be established to obtain acceptance by project managers and to promote injection of the technology into future science missions.

Integrated active and passive control design methodology for the LaRC CSI evolutionary model

NASA Technical Reports Server (NTRS)

Voth, Christopher T.; Richards, Kenneth E., Jr.; Schmitz, Eric; Gehling, Russel N.; Morgenthaler, Daniel R.

1994-01-01

A general design methodology to integrate active control with passive damping was demonstrated on the NASA LaRC CSI Evolutionary Model (CEM), a ground testbed for future large, flexible spacecraft. Vibration suppression controllers designed for Line-of Sight (LOS) minimization were successfully implemented on the CEM. A frequency-shaped H2 methodology was developed, allowing the designer to specify the roll-off of the MIMO compensator. A closed loop bandwidth of 4 Hz, including the six rigid body modes and the first three dominant elastic modes of the CEM was achieved. Good agreement was demonstrated between experimental data and analytical predictions for the closed loop frequency response and random tests. Using the Modal Strain Energy (MSE) method, a passive damping treatment consisting of 60 viscoelastically damped struts was designed, fabricated and implemented on the CEM. Damping levels for the targeted modes were more than an order of magnitude larger than for the undamped structure. Using measured loss and stiffness data for the individual damped struts, analytical predictions of the damping levels were very close to the experimental values in the (1-10) Hz frequency range where the open loop model matched the experimental data. An integrated active/passive controller was successfully implemented on the CEM and was evaluated against an active-only controller. A two-fold increase in the effective control bandwidth and further reductions of 30 percent to 50 percent in the LOS RMS outputs were achieved compared to an active-only controller. Superior performance was also obtained compared to a High-Authority/Low-Authority (HAC/LAC) controller.

Psychometric Evaluation of a Coping Strategies Inventory Short-Form (CSI-SF) in the Jackson Heart Study Cohort

PubMed Central

Addison, Clifton C.; Campbell-Jenkins, Brenda W.; Sarpong, Daniel F.; Kibler, Jeffery; Singh, Madhu; Dubbert, Patricia; Wilson, Gregory; Payne, Thomas; Taylor, Herman

2007-01-01

This study sought to establish the psychometric properties of a Coping Strategies Inventory Short Form (CSI-SF) by examining coping skills in the Jackson Heart Study cohort. We used exploratory and confirmatory factor analysis, Pearson’s correlation, and Cronbach Alpha to examine reliability and validity in the CSI-SF that solicited responses from 5302 African American men and women between the ages of 35 and 84. One item was dropped from the 16-item CSI-SF, making it a 15-item survey. No significant effects were found for age and gender, strengthening the generalizability of the CSI-SF. The internal consistency reliability analysis revealed reliability between alpha = 0.58–0.72 for all of the scales, and all of the fit indices used to examine the CSI-SF provided support for its use as an adequate measure of coping. This study provides empirical support for utilizing this instrument in future efforts to understand the role of coping in moderating health outcomes. PMID:18180539

WiFi-based person identification

NASA Astrophysics Data System (ADS)

Yuan, Jing

2016-10-01

There has been increased interest in WIFI devices equipped with multiple antennas, which brings various wireless sensing applications such as localization, gesture identification and motion tracking. WIFI-based sensing has a lot of benefits such as device Free, which has shown great potential in smart scenarios. In this paper, we present WIP, a system that can distinguish a person from a small group of people. We prove that Channel State Information (CSI) can identify a person's gait. From the related-work, different people have different gait features. Thus the CSI-based gait features can be used to identify a person. We then proposed a machine-learning model-ANN to classify different person. The results show that ANN has a good performance in our scenario.

Analysis, preliminary design and simulation systems for control-structure interaction problems

NASA Technical Reports Server (NTRS)

Park, K. C.; Alvin, Kenneth F.

1991-01-01

Software aspects of control-structure interaction (CSI) analysis are discussed. The following subject areas are covered: (1) implementation of a partitioned algorithm for simulation of large CSI problems; (2) second-order discrete Kalman filtering equations for CSI simulations; and (3) parallel computations and control of adaptive structures.

The NASA controls-structures interaction technology program

NASA Technical Reports Server (NTRS)

Newsom, Jerry R.; Layman, W. E.; Waites, H. B.; Hayduk, R. J.

1990-01-01

The interaction between a flexible spacecraft structure and its control system is commonly referred to as controls-structures interaction (CSI). The CSI technology program is developing the capability and confidence to integrate the structure and control system, so as to avoid interactions that cause problems and to exploit interactions to increase spacecraft capability. A NASA program has been initiated to advance CSI technology to a point where it can be used in spacecraft design for future missions. The CSI technology program is a multicenter program utilizing the resources of the NASA Langley Research Center (LaRC), the NASA Marshall Space Flight Center (MSFC), and the NASA Jet Propulsion Laboratory (JPL). The purpose is to describe the current activities, results to date, and future activities of the NASA CSI technology program.

Validation of the CSI health station 6K blood pressure kiosk.

PubMed

Buxton, Iain L O; Adams, John Q; Gore, Mark; Sullivan, Charles R

2007-01-01

Established in 1978, Computerized Screening Inc. (CSI) is the manufacturer of medical kiosks that combine non-invasive & invasive preventive health-screening technology and services in the U.S. The centerpiece of CSl's health complement is the CSI Health Station, one-stop health information and screening using patented technology. The CSI Health Station (Model 6K) represents the corporation's evolution from its self-administered automated blood pressure monitors (Model 3K). CSI Health Stations also offer touch screen activated heart rate testing, patented, seated weight measurement and fitness evaluations plus other non-invasive features like BMI, resting metabolic rate, spirometry, pulse oximetry and customized health risk assessments or triage guidelines. Invasive testing such as urine analysis, cholesterol, and glucose is also accommodated in an attended setting. In addition, CSI Health Stations feature comprehensive, one-stop availability of health information, with access to a drug encyclopedia and an extensive library of health education videos, and information on local health providers and services. It also is web enabled and supports secure website access direct from the kiosk. The purpose of this study was to determine, using current standards from the Association for the Advancement of Medical Instrumentation (AAMI), whether or not the CSI 6K could accurately and reproducibly measure blood pressure in an ambulatory population in comparison to manual auscultation.

S1-S3 counter charges in the voltage sensor module of a mammalian sodium channel regulate fast inactivation.

PubMed

Groome, James R; Winston, Vern

2013-05-01

The movement of positively charged S4 segments through the electric field drives the voltage-dependent gating of ion channels. Studies of prokaryotic sodium channels provide a mechanistic view of activation facilitated by electrostatic interactions of negatively charged residues in S1 and S2 segments, with positive counterparts in the S4 segment. In mammalian sodium channels, S4 segments promote domain-specific functions that include activation and several forms of inactivation. We tested the idea that S1-S3 countercharges regulate eukaryotic sodium channel functions, including fast inactivation. Using structural data provided by bacterial channels, we constructed homology models of the S1-S4 voltage sensor module (VSM) for each domain of the mammalian skeletal muscle sodium channel hNaV1.4. These show that side chains of putative countercharges in hNaV1.4 are oriented toward the positive charge complement of S4. We used mutagenesis to define the roles of conserved residues in the extracellular negative charge cluster (ENC), hydrophobic charge region (HCR), and intracellular negative charge cluster (INC). Activation was inhibited with charge-reversing VSM mutations in domains I-III. Charge reversal of ENC residues in domains III (E1051R, D1069K) and IV (E1373K, N1389K) destabilized fast inactivation by decreasing its probability, slowing entry, and accelerating recovery. Several INC mutations increased inactivation from closed states and slowed recovery. Our results extend the functional characterization of VSM countercharges to fast inactivation, and support the premise that these residues play a critical role in domain-specific gating transitions for a mammalian sodium channel.

Defective calcium inactivation causes long QT in obese insulin-resistant rat.

PubMed

Lin, Yen-Chang; Huang, Jianying; Kan, Hong; Castranova, Vincent; Frisbee, Jefferson C; Yu, Han-Gang

2012-02-15

The majority of diabetic patients who are overweight or obese die of heart disease. We suspect that the obesity-induced insulin resistance may lead to abnormal cardiac electrophysiology. We tested this hypothesis by studying an obese insulin-resistant rat model, the obese Zucker rat (OZR). Compared with the age-matched control, lean Zucker rat (LZR), OZR of 16-17 wk old exhibited an increase in QTc interval, action potential duration, and cell capacitance. Furthermore, the L-type calcium current (I(CaL)) in OZR exhibited defective inactivation and lost the complete inactivation back to the closed state, leading to increased Ca(2+) influx. The current density of I(CaL) was reduced in OZR, whereas the threshold activation and the current-voltage relationship of I(CaL) were not significantly altered. L-type Ba(2+) current (I(BaL)) in OZR also exhibited defective inactivation, and steady-state inactivation was not significantly altered. However, the current-voltage relationship and activation threshold of I(BaL) in OZR exhibited a depolarized shift compared with LZR. The total and membrane protein expression levels of Cav1.2 [pore-forming subunit of L-type calcium channels (LTCC)], but not the insulin receptors, were decreased in OZR. The insulin receptor was found to be associated with the Cav1.2, which was weakened in OZR. The total protein expression of calmodulin was reduced, but that of Cavβ2 subunit was not altered in OZR. Together, these results suggested that the 16- to 17-wk-old OZR has 1) developed cardiac hypertrophy, 2) exhibited altered electrophysiology manifested by the prolonged QTc interval, 3) increased duration of action potential in isolated ventricular myocytes, 4) defective inactivation of I(CaL) and I(BaL), 5) weakened the association of LTCC with the insulin receptor, and 6) decreased protein expression of Cav1.2 and calmodulin. These results also provided mechanistic insights into a remodeled cardiac electrophysiology under the condition of insulin resistance, enhancing our understanding of long QT associated with obese type 2 diabetic patients.

Characterization of scintillator-based detectors for few-ten-keV high-spatial-resolution x-ray imaging

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

Larsson, Jakob C., E-mail: jakob.larsson@biox.kth.se; Lundström, Ulf; Hertz, Hans M.

2016-06-15

Purpose: High-spatial-resolution x-ray imaging in the few-ten-keV range is becoming increasingly important in several applications, such as small-animal imaging and phase-contrast imaging. The detector properties critically influence the quality of such imaging. Here the authors present a quantitative comparison of scintillator-based detectors for this energy range and at high spatial frequencies. Methods: The authors determine the modulation transfer function, noise power spectrum (NPS), and detective quantum efficiency for Gadox, needle CsI, and structured CsI scintillators of different thicknesses and at different photon energies. An extended analysis of the NPS allows for direct measurements of the scintillator effective absorption efficiency andmore » effective light yield as well as providing an alternative method to assess the underlying factors behind the detector properties. Results: There is a substantial difference in performance between the scintillators depending on the imaging task but in general, the CsI based scintillators perform better than the Gadox scintillators. At low energies (16 keV), a thin needle CsI scintillator has the best performance at all frequencies. At higher energies (28–38 keV), the thicker needle CsI scintillators and the structured CsI scintillator all have very good performance. The needle CsI scintillators have higher absorption efficiencies but the structured CsI scintillator has higher resolution. Conclusions: The choice of scintillator is greatly dependent on the imaging task. The presented comparison and methodology will assist the imaging scientist in optimizing their high-resolution few-ten-keV imaging system for best performance.« less

Characterization of scintillator-based detectors for few-ten-keV high-spatial-resolution x-ray imaging.

PubMed

Larsson, Jakob C; Lundström, Ulf; Hertz, Hans M

2016-06-01

High-spatial-resolution x-ray imaging in the few-ten-keV range is becoming increasingly important in several applications, such as small-animal imaging and phase-contrast imaging. The detector properties critically influence the quality of such imaging. Here the authors present a quantitative comparison of scintillator-based detectors for this energy range and at high spatial frequencies. The authors determine the modulation transfer function, noise power spectrum (NPS), and detective quantum efficiency for Gadox, needle CsI, and structured CsI scintillators of different thicknesses and at different photon energies. An extended analysis of the NPS allows for direct measurements of the scintillator effective absorption efficiency and effective light yield as well as providing an alternative method to assess the underlying factors behind the detector properties. There is a substantial difference in performance between the scintillators depending on the imaging task but in general, the CsI based scintillators perform better than the Gadox scintillators. At low energies (16 keV), a thin needle CsI scintillator has the best performance at all frequencies. At higher energies (28-38 keV), the thicker needle CsI scintillators and the structured CsI scintillator all have very good performance. The needle CsI scintillators have higher absorption efficiencies but the structured CsI scintillator has higher resolution. The choice of scintillator is greatly dependent on the imaging task. The presented comparison and methodology will assist the imaging scientist in optimizing their high-resolution few-ten-keV imaging system for best performance.

Association analyses of vitamin D-binding protein gene with compression strength index variation in Caucasian nuclear families.

PubMed

Xu, X-H; Xiong, D-H; Liu, X-G; Guo, Y; Chen, Y; Zhao, J; Recker, R R; Deng, H-W

2010-01-01

This study was conducted to test whether there exists an association between vitamin D-binding protein (DBP) gene and compression strength index (CSI) phenotype. Candidate gene association analyses were conducted in total sample, male subgroup, and female subgroup, respectively. Two single-nucleotide polymorphisms (SNPs) with significant association results were found in males, suggesting the importance of DBP gene polymorphisms on the variation in CSI especially in Caucasian males. CSI of the femoral neck (FN) is a newly developed phenotype integrating information about bone size, body size, and bone mineral density. It is considered to have the potential to improve the performance of risk assessment for hip fractures because it is based on a combination of phenotypic traits influencing hip fractures rather than a single trait. CSI is under moderate genetic determination (with a heritability of approximately 44% found in this study), but the relevant genetic study is still rather scarce. Based on the known physiological role of DBP in bone biology and the relatively high heritability of CSI, we tested 12 SNPs of the DBP gene for association with CSI variation in 405 Caucasian nuclear families comprising 1,873 subjects from the Midwestern US. Association analyses were performed in the total sample, male and female subgroups, respectively. Significant associations with CSI were found with two SNPs (rs222029, P = 0.0019; rs222020, P = 0.0042) for the male subgroup. Haplotype-based association tests corroborated the single-SNP results. Our findings suggest that the DBP gene might be one of the genetic factors influencing CSI phenotype in Caucasians, especially in males.

Channel estimation in few mode fiber mode division multiplexing transmission system

NASA Astrophysics Data System (ADS)

Hei, Yongqiang; Li, Li; Li, Wentao; Li, Xiaohui; Shi, Guangming

2018-03-01

It is abundantly clear that obtaining the channel state information (CSI) is of great importance for the equalization and detection in coherence receivers. However, to the best of the authors' knowledge, in most of the existing literatures, CSI is assumed to be perfectly known at the receiver. So far, few literature discusses the effects of imperfect CSI on MDM system performance caused by channel estimation. Motivated by that, in this paper, the channel estimation in few mode fiber (FMF) mode division multiplexing (MDM) system is investigated, in which two classical channel estimation methods, i.e., least square (LS) method and minimum mean square error (MMSE) method, are discussed with the assumption of the spatially white noise lumped at the receiver side of MDM system. Both the capacity and BER performance of MDM system affected by mode-dependent gain or loss (MDL) with different channel estimation errors have been studied. Simulation results show that the capacity and BER performance can be further deteriorated in MDM system by the channel estimation, and an 1e-3 variance of channel estimation error is acceptable in MDM system with 0-6 dB MDL values.

Highly effective electronic passivation of silicon surfaces by atomic layer deposited hafnium oxide

NASA Astrophysics Data System (ADS)

Cui, Jie; Wan, Yimao; Cui, Yanfeng; Chen, Yifeng; Verlinden, Pierre; Cuevas, Andres

2017-01-01

This paper investigates the application of hafnium oxide (HfO2) thin films to crystalline silicon (c-Si) solar cells. Excellent passivation of both n- and p-type crystalline silicon surfaces has been achieved by the application of thin HfO2 films prepared by atomic layer deposition. Effective surface recombination velocities as low as 3.3 and 9.9 cm s-1 have been recorded with 15 nm thick films on n- and p-type 1 Ω cm c-Si, respectively. The surface passivation by HfO2 is activated at 350 °C by a forming gas anneal. Capacitance voltage measurement shows an interface state density of 3.6 × 1010 cm-2 eV-1 and a positive charge density of 5 × 1011 cm-2 on annealed p-type 1 Ω cm c-Si. X-ray diffraction unveils a positive correlation between surface recombination and crystallinity of the HfO2 and a dependence of the crystallinity on both annealing temperature and film thickness. In summary, HfO2 is demonstrated to be an excellent candidate for surface passivation of crystalline silicon solar cells.

Robust Rate Maximization for Heterogeneous Wireless Networks under Channel Uncertainties

PubMed Central

Xu, Yongjun; Hu, Yuan; Li, Guoquan

2018-01-01

Heterogeneous wireless networks are a promising technology in next generation wireless communication networks, which has been shown to efficiently reduce the blind area of mobile communication and improve network coverage compared with the traditional wireless communication networks. In this paper, a robust power allocation problem for a two-tier heterogeneous wireless networks is formulated based on orthogonal frequency-division multiplexing technology. Under the consideration of imperfect channel state information (CSI), the robust sum-rate maximization problem is built while avoiding sever cross-tier interference to macrocell user and maintaining the minimum rate requirement of each femtocell user. To be practical, both of channel estimation errors from the femtocells to the macrocell and link uncertainties of each femtocell user are simultaneously considered in terms of outage probabilities of users. The optimization problem is analyzed under no CSI feedback with some cumulative distribution function and partial CSI with Gaussian distribution of channel estimation error. The robust optimization problem is converted into the convex optimization problem which is solved by using Lagrange dual theory and subgradient algorithm. Simulation results demonstrate the effectiveness of the proposed algorithm by the impact of channel uncertainties on the system performance. PMID:29466315

Cement paste surface roughness analysis using coherence scanning interferometry and confocal microscopy

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

Apedo, K.L., E-mail: apedo@unistra.fr; Munzer, C.; He, H.

2015-02-15

Scanning electron microscopy and scanning probe microscopy have been used for several decades to better understand the microstructure of cementitious materials. Very limited work has been performed to date to study the roughness of cementitious materials by optical microscopy such as coherence scanning interferometry (CSI) and chromatic confocal sensing (CCS). The objective of this paper is to better understand how CSI can be used as a tool to analyze surface roughness and topography of cement pastes. Observations from a series of images acquired using this technique on both polished and unpolished samples are described. The results from CSI are comparedmore » with those from a STIL confocal microscopy technique (SCM). Comparison between both optical techniques demonstrates the ability of CSI to measure both polished and unpolished cement pastes. - Highlights: • Coherence scanning interferometry (CSI) was used to analyze cement paste surfaces. • The results from the CSI were compared with those from a confocal microscopy. • 3D roughness parameters were obtained using the window resizing method. • Polished and unpolished cement pastes were studied.« less

Joint Transmitter and Receiver Power Allocation under Minimax MSE Criterion with Perfect and Imperfect CSI for MC-CDMA Transmissions

NASA Astrophysics Data System (ADS)

Kotchasarn, Chirawat; Saengudomlert, Poompat

We investigate the problem of joint transmitter and receiver power allocation with the minimax mean square error (MSE) criterion for uplink transmissions in a multi-carrier code division multiple access (MC-CDMA) system. The objective of power allocation is to minimize the maximum MSE among all users each of which has limited transmit power. This problem is a nonlinear optimization problem. Using the Lagrange multiplier method, we derive the Karush-Kuhn-Tucker (KKT) conditions which are necessary for a power allocation to be optimal. Numerical results indicate that, compared to the minimum total MSE criterion, the minimax MSE criterion yields a higher total MSE but provides a fairer treatment across the users. The advantages of the minimax MSE criterion are more evident when we consider the bit error rate (BER) estimates. Numerical results show that the minimax MSE criterion yields a lower maximum BER and a lower average BER. We also observe that, with the minimax MSE criterion, some users do not transmit at full power. For comparison, with the minimum total MSE criterion, all users transmit at full power. In addition, we investigate robust joint transmitter and receiver power allocation where the channel state information (CSI) is not perfect. The CSI error is assumed to be unknown but bounded by a deterministic value. This problem is formulated as a semidefinite programming (SDP) problem with bilinear matrix inequality (BMI) constraints. Numerical results show that, with imperfect CSI, the minimax MSE criterion also outperforms the minimum total MSE criterion in terms of the maximum and average BERs.

Effect of Common Drinking Water Disinfectants, Chlorine and Heat, on Free Legionella and Amoebae-Associated Legionella

PubMed Central

Cervero-Aragó, Sílvia; Rodríguez-Martínez, Sarah; Puertas-Bennasar, Antoni; Araujo, Rosa M.

2015-01-01

Chlorine and thermal treatments are the most commonly used procedures to control and prevent Legionella proliferation in drinking water systems of large buildings. However, cases of legionellosis still occur in facilities with treated water. The purpose of this work was to model the effect of temperature and free chlorine applied in similar exposure conditions as in drinking water systems on five Legionella spp. strains and two amoebal strains of the genera Acanthamoeba. Inactivation models obtained were used to determine the effectiveness of the treatments applied which resulted more effective against Legionella than Acanthamoeba, especially those in cystic stages. Furthermore, to determine the influence of the relationship between L. pneumophila and Acanthamoeba spp. on the treatment effectiveness, inactivation models of the bacteria-associated amoeba were also constructed and compared to the models obtained for the free living bacteria state. The Legionella-amoeba association did not change the inactivation models, but it reduced the effectiveness of the treatments applied. Remarkably, at the lowest free chlorine concentration, 0.5 mg L-1, as well as at the lowest temperatures, 50°C and 55°C, the influence of the Legionella-amoeba associate state was the strongest in reducing the effectiveness of the treatments compared to the free Legionella state. Therefore, the association established between L. pneumophila and amoebae in the water systems indicate an increased health risk in proximal areas of the system (close to the tap) where lower free chlorine concentrations and lower temperatures are commonly observed. PMID:26241039

Monitoring Drought along the Gulf of Mexico and the Southeastern Atlantic Ocean Using the Coastal Salinity Index

NASA Astrophysics Data System (ADS)

Conrads, P. A.; Rouen, L.; Lackstrom, K.; McCloskey, B.

2017-12-01

Coastal droughts have a different dynamic than upland droughts, which are typically characterized by agricultural, hydrologic, meteorological, and (or) socio-economic impacts. Drought uniquely affects coastal ecosystems due to changes in salinity conditions of estuarine creeks and rivers. The location of the freshwater-saltwater interface in surface-water bodies is an important factor in the ecological and socio-economic dynamics of coastal communities. The location of the interface determines the freshwater and saltwater aquatic communities, fisheries spawning habitat, and the freshwater availability for municipal and industrial water intakes. The severity of coastal drought may explain changes in Vibrio bacteria impacts on shellfish harvesting and occurrence of wound infection, fish kills, harmful algal blooms, hypoxia, and beach closures. To address the data and information gap for characterizing coastal drought, a coastal salinity index (CSI) was developed using salinity data. The CSI uses a computational approach similar to the Standardized Precipitation Index (SPI). The CSI is computed for unique time intervals (for example 1-, 6-, 12-, and 24-month) that can characterize the onset and recovery of short- and long-term drought. Evaluation of the CSI indicates that the index can be used for different estuary types (for example: brackish, oligohaline, or mesohaline), for regional comparison between estuaries, and as an index of wet conditions (high freshwater inflow) in addition to drought (saline) conditions. In 2017, three activities in 2017 will be presented that enhance the use and application of the CSI. One, a software package was developed for the consistent computation of the CSI that includes preprocessing of salinity data, filling missing data, computing the CSI, post-processing, and generating the supporting metadata. Two, the CSI has been computed at sites along the Gulf of Mexico (Texas to Florida) and the Southeastern Atlantic Ocean (Florida to North Carolina), and three, using telemetered salinity data, the real-time computation of the CSI has been prototyped and disseminated on the web.

Ab initio study of the effects of thin CsI coatings on the work function of graphite cathodes

NASA Astrophysics Data System (ADS)

Vlahos, Vasilios; Booske, John H.; Morgan, Dane

2007-10-01

Cesium-iodide (CsI)-coated graphite cathodes are promising electron sources for high power microwave generators, but the mechanism driving the improved emission is not well understood. Therefore, an ab initio modeling investigation on the effects of thin CsI coatings on graphite has been carried out. It is demonstrated that the CsI coatings reduce the work function of the system significantly through a mechanism of induced dipoles. The results suggest that work function modification is a major contribution to the improved emission seen when CsI coatings are applied to C.

Controls-Structures Interaction (CSI) technology program summary. Earth orbiting platforms program area of the space platforms technology program

NASA Technical Reports Server (NTRS)

Newsom, Jerry R.

1991-01-01

Control-Structures Interaction (CSI) technology embraces the understanding of the interaction between the spacecraft structure and the control system, and the creation and validation of concepts, techniques, and tools, for enabling the interdisciplinary design of an integrated structure and control system, rather than the integration of a structural design and a control system design. The goal of this program is to develop validated CSI technology for integrated design/analysis and qualification of large flexible space systems and precision space structures. A description of the CSI technology program is presented.

The Effect of Various Types of Motorcycle Helmets on Cervical Spine Injury in Head Injury Patients: A Multicenter Study in Taiwan

PubMed Central

Lin, Mau-Roung; Chu, Shu-Fen; Tsai, Shin-Han; Bai, Chyi-Huey; Chiu, Wen-Ta

2015-01-01

Introduction. The relationship between cervical spine injury (CSI) and helmet in head injury (HI) patients following motorcycle crashes is crucial. Controversy still exists; therefore we evaluated the effect of various types of helmets on CSI in HI patients following motorcycle crashes and researched the mechanism of this effect. Patients and Methods. A total of 5225 patients of motorcycle crashes between 2000 and 2009 were extracted from the Head Injury Registry in Taiwan. These patients were divided into case and control groups according to the presence of concomitant CSI. Helmet use and types were separately compared between the two groups and the odds ratio of CSI was obtained by using multiple logistic regression analysis. Results. We observed that 173 (3.3%) of the HI patients were associated with CSI. The HI patients using a helmet (odds ratio (OR) = 0.31, 95% confidence interval (CI) = 0.19−0.49), full-coverage helmet (0.19, 0.10−0.36), and partial-coverage helmet (0.35, 0.21−0.56) exhibited a significantly decreased rate of CSI compared with those without a helmet. Conclusion. Wearing full-coverage and partial-coverage helmets significantly reduced the risk of CSI among HI patients following motorcycle crashes. This effect may be due to the smooth surface and hard padding materials of helmet. PMID:25705663

Modeling of Single Noninactivating Na+ Channels: Evidence for Two Open and Several Fast Inactivated States

PubMed Central

The, Yu-Kai; Fernandes, Jacqueline; Popa, M. Oana; Alekov, Alexi K.; Timmer, Jens; Lerche, Holger

2006-01-01

Voltage-gated Na+ channels play a fundamental role in the excitability of nerve and muscle cells. Defects in fast Na+ channel inactivation can cause hereditary muscle diseases with hyper- or hypoexcitability of the sarcolemma. To explore the kinetics and gating mechanisms of noninactivating muscle Na+ channels on a molecular level, we analyzed single channel currents from wild-type and five mutant Na+ channels. The mutations were localized in different protein regions which have been previously shown to be important for fast inactivation (D3-D4-linker, D3/S4-S5, D4/S4-S5, D4/S6) and exhibited distinct grades of defective fast inactivation with varying levels of persistent Na+ currents caused by late channel reopenings. Different gating schemes were fitted to the data using hidden Markov models with a correction for time interval omission and compared statistically. For all investigated channels including the wild-type, two open states were necessary to describe our data. Whereas one inactivated state was sufficient to fit the single channel behavior of wild-type channels, modeling the mutants with impaired fast inactivation revealed evidence for several inactivated states. We propose a single gating scheme with two open and three inactivated states to describe the behavior of all five examined mutants. This scheme provides a biological interpretation of the collected data, based on previous investigations in voltage-gated Na+ and K+ channels. PMID:16513781

Development and Analyses of the Coping Stress Inventory

ERIC Educational Resources Information Center

Gadzella, Bernadette M.; Pierce, Devin; Young, Adena

2008-01-01

This is a report on the development of a coping stress inventory and the analyses of the data collected from 344 participants. The Coping Stress Inventory, CSI, with 16 items intercorrelated in the categories (Behavioral, Emotional, and Cognitive Appraisal). The internal consistency for the CSI was 0.77. Responses to the CSI were compared (a)…

Highly-accelerated quantitative 2D and 3D localized spectroscopy with linear algebraic modeling (SLAM) and sensitivity encoding

NASA Astrophysics Data System (ADS)

Zhang, Yi; Gabr, Refaat E.; Zhou, Jinyuan; Weiss, Robert G.; Bottomley, Paul A.

2013-12-01

Noninvasive magnetic resonance spectroscopy (MRS) with chemical shift imaging (CSI) provides valuable metabolic information for research and clinical studies, but is often limited by long scan times. Recently, spectroscopy with linear algebraic modeling (SLAM) was shown to provide compartment-averaged spectra resolved in one spatial dimension with many-fold reductions in scan-time. This was achieved using a small subset of the CSI phase-encoding steps from central image k-space that maximized the signal-to-noise ratio. Here, SLAM is extended to two- and three-dimensions (2D, 3D). In addition, SLAM is combined with sensitivity-encoded (SENSE) parallel imaging techniques, enabling the replacement of even more CSI phase-encoding steps to further accelerate scan-speed. A modified SLAM reconstruction algorithm is introduced that significantly reduces the effects of signal nonuniformity within compartments. Finally, main-field inhomogeneity corrections are provided, analogous to CSI. These methods are all tested on brain proton MRS data from a total of 24 patients with brain tumors, and in a human cardiac phosphorus 3D SLAM study at 3T. Acceleration factors of up to 120-fold versus CSI are demonstrated, including speed-up factors of 5-fold relative to already-accelerated SENSE CSI. Brain metabolites are quantified in SLAM and SENSE SLAM spectra and found to be indistinguishable from CSI measures from the same compartments. The modified reconstruction algorithm demonstrated immunity to maladjusted segmentation and errors from signal heterogeneity in brain data. In conclusion, SLAM demonstrates the potential to supplant CSI in studies requiring compartment-average spectra or large volume coverage, by dramatically reducing scan-time while providing essentially the same quantitative results.

Azithromycin analogue CSY0073 attenuates lung inflammation induced by LPS challenge

PubMed Central

Balloy, V; Deveaux, A; Lebeaux, D; Tabary, O; le Rouzic, P; Ghigo, J M; Busson, P F; Boëlle, P Y; Guez, J Guez; Hahn, U; Clement, A; Chignard, M; Corvol, H; Burnet, M; Guillot, L

2014-01-01

Background and Purpose Azithromycin is a macrolide antibiotic with anti-inflammatory and immunomodulating effects. Long-term azithromycin therapy in patients with chronic lung diseases such as cystic fibrosis has been associated with increased antimicrobial resistance, emergence of hypermutable strains, ototoxicity and cardiac toxicity. The aim of this study was to assess the anti-inflammatory effects of the non-antibiotic azithromycin derivative CSY0073. Experimental Approach We compared the effects of CSY0073 with those of azithromycin in experiments on bacterial cultures, Pseudomonas aeruginosa biofilm, lung cells and mice challenged intranasally with P. aeruginosa LPS. Key Results In contrast to azithromycin, CSY0073 did not inhibit the growth of P. aeruginosa, Staphylococcus aureus or Haemophilus influenzae and had no effect on an established P. aeruginosa biofilm. Bronchoalveolar lavage (BAL) fluids and lung homogenates collected after the LPS challenge in mice showed that CSY0073 and azithromycin (200 mg·kg−1, i.p.) decreased neutrophil counts at 24 h and TNF-α, CXCL1 and CXCL2 levels in the BAL fluid after 3 h and IL-6, CXCL2 and IL-1β levels in the lung after 3 h compared with the vehicle. However, only azithromycin reduced IL-1β levels in the lung 24 h post LPS challenge. CSY0073 and azithromycin similarly diminished the production of pro-inflammatory cytokines by macrophages, but not lung epithelial cells, exposed to P. aeruginosa LPS. Conclusions and Implications Unlike azithromycin, CSY0073 had no antibacterial effects but it did have a similar anti-inflammatory profile to that of azithromycin. Hence, CSY0073 may have potential as a long-term treatment for patients with chronic lung diseases. PMID:24417187

Association analyses of vitamin D-binding protein gene with compression strength index variation in Caucasian nuclear families

PubMed Central

Xu, X.-H.; Xiong, D.-H.; Liu, X.-G.; Guo, Y.; Chen, Y.; Zhao, J.; Recker, R. R.; Deng, H.-W.

2010-01-01

Summary This study was conducted to test whether there exists an association between vitamin D-binding protein (DBP) gene and compression strength index (CSI) phenotype. Candidate gene association analyses were conducted in total sample, male subgroup, and female subgroup, respectively. Two single-nucleotide polymorphisms (SNPs) with significant association results were found in males, suggesting the importance of DBP gene polymorphisms on the variation in CSI especially in Caucasian males. Introduction CSI of the femoral neck (FN) is a newly developed phenotype integrating information about bone size, body size, and bone mineral density. It is considered to have the potential to improve the performance of risk assessment for hip fractures because it is based on a combination of phenotypic traits influencing hip fractures rather than a single trait. CSI is under moderate genetic determination (with a heritability of ~44% found in this study), but the relevant genetic study is still rather scarce. Methods Based on the known physiological role of DBP in bone biology and the relatively high heritability of CSI, we tested 12 SNPs of the DBP gene for association with CSI variation in 405 Caucasian nuclear families comprising 1,873 subjects from the Midwestern US. Association analyses were performed in the total sample, male and female subgroups, respectively. Results Significant associations with CSI were found with two SNPs (rs222029, P=0.0019; rs222020, P=0.0042) for the male subgroup. Haplotype-based association tests corroborated the single-SNP results. Conclusions Our findings suggest that the DBP gene might be one of the genetic factors influencing CSI phenotype in Caucasians, especially in males. PMID:19543766

Tuning the colors of c-Si solar cells by exploiting plasmonic effects

NASA Astrophysics Data System (ADS)

Peharz, G.; Grosschädl, B.; Prietl, C.; Waldhauser, W.; Wenzl, F. P.

2016-09-01

The color of a crystalline silicon (c-Si) solar cell is mainly determined by its anti-reflective coating. This is a lambda/4 coating made from a transparent dielectric material. The thickness of the anti-reflective coating is optimized for maximal photocurrent generation, resulting in the typical blue or black colors of c-Si solar cells. However, for building-integrated photovoltaic (BiPV) applications the color of the solar cells is demanded to be tunable - ideally by a cheap and flexible coating process on standard (low cost) c-Si solar cells. Such a coating can be realized by applying plasmonic coloring which is a rapidly growing technology for high-quality color filtering and rendering for different fields of application (displays, imaging,…). In this contribution, we present results of an approach for tuning the color of standard industrial c-Si solar cells that is based on coating them with metallic nano-particles. In particular, thin films (< 20 nm) of a metal (e.g., silver) were sputtered onto c-Si solar cells and thermally annealed subsequently. The sizes and the shapes of the nano-particles (characterized by SEM) were found to depend on the thickness of the deposited films and the surface roughness of the substrates/solar cells. With such an approach it is possible to tune the color of the standard c-Si cells from blue to green and brownish/red. The position of the resonance peak in the reflection spectrum was found to be almost independent from the angle of incidence. This low angular sensitivity is a clear advantage compared to alternative color tuning methods, for which additional dielectric thin films are deposited on c-Si solar cells.

Treatment Outcomes of Corticosteroid Injection and Extracorporeal Shock Wave Therapy as Two Primary Therapeutic Methods for Acute Plantar Fasciitis: A Prospective Randomized Clinical Trial.

PubMed

Mardani-Kivi, Mohsen; Karimi Mobarakeh, Mahmoud; Hassanzadeh, Zabihallah; Mirbolook, Ahmadreza; Asadi, Kamran; Ettehad, Hossein; Hashemi-Motlagh, Keyvan; Saheb-Ekhtiari, Khashayar; Fallah-Alipour, Keyvan

2015-01-01

The outcome of corticosteroid injection (CSI) and extracorporeal shock wave therapy (ESWT) as primary treatment of acute plantar fasciitis has been debated. The purpose of the present study was to evaluate and compare the therapeutic effects of CSI and ESWT in patients with acute (<6-week duration) symptomatic plantar fasciitis. Of the 116 eligible patients, 68 were randomized to 2 equal groups of 34 patients, each undergoing either ESWT or CSI. The ESWT method included 2000 impulses with energy of 0.15 mJ/mm(2) and a total energy flux density of 900 mJ/mm(2) for 3 consecutive sessions at 1-week intervals. In the CSI group, 40 mg of methyl prednisolone acetate plus 1 mL of lidocaine 2% was injected into the maximal tenderness point at the inframedial calcaneal tuberosity. The success and recurrence rates and pain intensity measured using the visual analog scale, were recorded and compared at the 3-month follow-up visit. The pain intensity had reduced significantly in all patients undergoing either technique. However, the value and trend of pain reduction in the CSI group was significantly greater than those in the ESWT group (p < .0001). In the ESWT and CSI groups, 19 (55.9%) and 5 (14.7%) patients experienced treatment failure, respectively. Age, gender, body mass index, and recurrence rate were similar between the 2 groups (p > .05). Both ESWT and CSI can be used as the primary and/or initial treatment option for treating patients with acute plantar fasciitis; however, the CSI technique had better therapeutic outcomes. Copyright © 2015 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

Large-Scale Changes in Community Composition: Determining Land Use and Climate Change Signals

PubMed Central

Kampichler, Christian; van Turnhout, Chris A. M.; Devictor, Vincent; van der Jeugd, Henk P.

2012-01-01

Human land use and climate change are regarded as the main driving forces of present-day and future species extinction. They may potentially lead to a profound reorganisation of the composition and structure of natural communities throughout the world. However, studies that explicitly investigate both forms of impact—land use and climate change—are uncommon. Here, we quantify community change of Dutch breeding bird communities over the past 25 years using time lag analysis. We evaluate the chronological sequence of the community temperature index (CTI) which reflects community response to temperature increase (increasing CTI indicates an increase in relative abundance of more southerly species), and the temporal trend of the community specialisation index (CSI) which reflects community response to land use change (declining CSI indicates an increase of generalist species). We show that the breeding bird fauna underwent distinct directional change accompanied by significant changes both in CTI and CSI which suggests a causal connection between climate and land use change and bird community change. The assemblages of particular breeding habitats neither changed at the same speed and nor were they equally affected by climate versus land use changes. In the rapidly changing farmland community, CTI and CSI both declined slightly. In contrast, CTI increased in the more slowly changing forest and heath communities, while CSI remained stable. Coastal assemblages experienced both an increase in CTI and a decline in CSI. Wetland birds experienced the fastest community change of all breeding habitat assemblages but neither CTI nor CSI showed a significant trend. Overall, our results suggest that the interaction between climate and land use changes differs between habitats, and that comparing trends in CSI and CTI may be useful in tracking the impact of each determinant. PMID:22523579

Large-scale changes in community composition: determining land use and climate change signals.

PubMed

Kampichler, Christian; van Turnhout, Chris A M; Devictor, Vincent; van der Jeugd, Henk P

2012-01-01

Human land use and climate change are regarded as the main driving forces of present-day and future species extinction. They may potentially lead to a profound reorganisation of the composition and structure of natural communities throughout the world. However, studies that explicitly investigate both forms of impact--land use and climate change--are uncommon. Here, we quantify community change of Dutch breeding bird communities over the past 25 years using time lag analysis. We evaluate the chronological sequence of the community temperature index (CTI) which reflects community response to temperature increase (increasing CTI indicates an increase in relative abundance of more southerly species), and the temporal trend of the community specialisation index (CSI) which reflects community response to land use change (declining CSI indicates an increase of generalist species). We show that the breeding bird fauna underwent distinct directional change accompanied by significant changes both in CTI and CSI which suggests a causal connection between climate and land use change and bird community change. The assemblages of particular breeding habitats neither changed at the same speed and nor were they equally affected by climate versus land use changes. In the rapidly changing farmland community, CTI and CSI both declined slightly. In contrast, CTI increased in the more slowly changing forest and heath communities, while CSI remained stable. Coastal assemblages experienced both an increase in CTI and a decline in CSI. Wetland birds experienced the fastest community change of all breeding habitat assemblages but neither CTI nor CSI showed a significant trend. Overall, our results suggest that the interaction between climate and land use changes differs between habitats, and that comparing trends in CSI and CTI may be useful in tracking the impact of each determinant.

Investigating CSI: portrayals of DNA testing on a forensic crime show and their potential effects.

PubMed

Ley, Barbara L; Jankowski, Natalie; Brewer, Paul R

2012-01-01

The popularity of forensic crime shows such as CSI has fueled debate about their potential social impact. This study considers CSI's potential effects on public understandings regarding DNA testing in the context of judicial processes, the policy debates surrounding crime laboratory procedures, and the forensic science profession, as well as an effect not discussed in previous accounts: namely, the show's potential impact on public understandings of DNA and genetics more generally. To develop a theoretical foundation for research on the "CSI effect," it draws on cultivation theory, social cognitive theory, and audience reception studies. It then uses content analysis and textual analysis to illuminate how the show depicts DNA testing. The results demonstrate that CSI tends to depict DNA testing as routine, swift, useful, and reliable and that it echoes broader discourses about genetics. At times, however, the show suggests more complex ways of thinking about DNA testing and genetics.

Biomass Potential of Virgin and Calcined Tapioca (Cassava Starch) for the Removal of Sr(II) and Cs(I) from Aqueous Solutions.

PubMed

Ogata, Fumihiko; Nagai, Noriaki; Ueta, Erimi; Nakamura, Takehiro; Kawasaki, Naohito

2018-01-01

In this study, we prepared novel adsorbents containing virgin and calcined tapioca products for removing strontium (Sr(II)) and cesium (Cs(I)) from aqueous solutions. The characteristics of tapioca, along with its capacity to adsorb Sr(II) and Cs(I), were evaluated. Multiple tapioca products were prepared and tested. The adsorbent prepared by boiling the tapioca followed by calcination at 300°C (BTP300) was the most effective. In addition, adsorption was affected by the adsorbent's surface properties. The Sr(II) and Cs(I) adsorbed onto BTP300 could be recovered through desorption by hydrochloric acid at different concentrations, which indicates that BTP300 can be used several times for adsorption/desorption. The results of this study suggest that BTP300, which was produced from tapioca biomass, can remove Sr(II) and Cs(I) from aqueous solutions.

Characterization of SiCSiC Composites in Support of Environmental Degradation Modeling

NASA Technical Reports Server (NTRS)

Kiser, Doug; Sullivan, Roy; Bhatt, Ram; Smith, Craig; Zima, John; McCue, Terry

2016-01-01

SiCSiC (silicon carbide fiber reinforced silicon carbide) composites are candidate materials for various turbine engine applications because of their high specific strength and good creep and oxidation resistance at elevated temperatures. This study was performed to characterize the microstructure of a melt infiltrated (MI) SiCSiC, and to examine environmental degradation mechanisms occurring in precracked MI SiCSiC CMC specimens under tensile stresses of 30 ksi or less at 815C in dry air or argon. In addition, the oxidation of the BN interface was characterized at815C, and crack opening displacement as a function of stress measurements were made. This material characterization is being performed to obtain data to support NASA GRC modeling of SiCSiC environmental degradation. The comparison of experimentally-observed phenomena with model predictions can lead to improved understanding of material degradation mechanisms.

A performance analysis in AF full duplex relay selection network

NASA Astrophysics Data System (ADS)

Ngoc, Long Nguyen; Hong, Nhu Nguyen; Loan, Nguyen Thi Phuong; Kieu, Tam Nguyen; Voznak, Miroslav; Zdralek, Jaroslav

2018-04-01

This paper studies on the relaying selective matter in amplify-and-forward (AF) cooperation communication with full-duplex (FD) activity. Various relay choice models supposing the present of different instant information are investigated. We examine a maximal relaying choice that optimizes the instant FD channel capacity and asks for global channel state information (CSI) as well as partial CSI learning. To make comparison easy, accurate outage probability clauses and asymptote form of these strategies that give a diversity rank are extracted. From that, we can see clearly that the number of relays, noise factor, the transmittance coefficient as well as the information transfer power had impacted on their performance. Besides, the optimal relay selection (ORS) model can promote than that of the partial relay selection (PRS) model.

Inactivation of myeloma cancer cells by helium and argon plasma jets: The effect comparison and the key reactive species

NASA Astrophysics Data System (ADS)

Chen, Zeyu; Cui, Qingjie; Chen, Chen; Xu, Dehui; Liu, Dingxin; Chen, H. L.; Kong, Michael G.

2018-02-01

In plasma cancer therapy, the inactivation of cancer cells under plasma treatment is closely related to the reactive oxygen and nitrogen species (RONS) induced by plasmas. Quantitative study on the plasma-induced RONS that related to cancer cells apoptosis is critical for advancing the research of plasma cancer therapy. In this paper, the effects of several reactive species on the inactivation of LP-1 myeloma cancer cells are comparatively studied with variable working gas composition, surrounding gas composition, and discharge power. The results show that helium plasma jet has a higher cell inactivation efficiency than argon plasma jet under the same discharge power. By comparing the concentration of aqueous phase reactive species and the cell inactivation efficiency under different working gases and discharge powers, it is demonstrated that the inactivation efficiency of LP-1 myeloma cancer cells is strongly correlated with the concentration of peroxynitrite (ONOOH/ONOO-).

Achieving an Accurate Surface Profile of a Photonic Crystal for Near-Unity Solar Absorption in a Super Thin-Film Architecture.

PubMed

Kuang, Ping; Eyderman, Sergey; Hsieh, Mei-Li; Post, Anthony; John, Sajeev; Lin, Shawn-Yu

2016-06-28

In this work, a teepee-like photonic crystal (PC) structure on crystalline silicon (c-Si) is experimentally demonstrated, which fulfills two critical criteria in solar energy harvesting by (i) its Gaussian-type gradient-index profile for excellent antireflection and (ii) near-orthogonal energy flow and vortex-like field concentration via the parallel-to-interface refraction effect inside the structure for enhanced light trapping. For the PC structure on 500-μm-thick c-Si, the average reflection is only ∼0.7% for λ = 400-1000 nm. For the same structure on a much thinner c-Si ( t = 10 μm), the absorption is near unity (A ∼ 99%) for visible wavelengths, while the absorption in the weakly absorbing range (λ ∼ 1000 nm) is significantly increased to 79%, comparing to only 6% absorption for a 10-μm-thick planar c-Si. In addition, the average absorption (∼94.7%) of the PC structure on 10 μm c-Si for λ = 400-1000 nm is only ∼3.8% less than the average absorption (∼98.5%) of the PC structure on 500 μm c-Si, while the equivalent silicon solid content is reduced by 50 times. Furthermore, the angular dependence measurements show that the high absorption is sustained over a wide angle range (θinc = 0-60°) for teepee-like PC structure on both 500 and 10-μm-thick c-Si.

Container Security: A Proposal for a Comprehensive Code of Conduct

DTIC Science & Technology

2005-01-01

the CTPAT . • U.S. Customs will offer potential benefits to C-TPAT members, including: a reduced number of inspections (reduced border times); an...in mind and building upon previous activities by the United States (CSI, CTPAT and PSI), the EU, and international organizations such as the WCO and

Installation Restoration Program. Phase I. Records Search. Vandenberg Air Force Base, California.

DTIC Science & Technology

1984-12-01

acidity or alkalinity POL Petroleum, oils, and lubricants PVC Polyvinyl chloride plastic RCRA Resource Conservation and Recovery Act RP-1 Rocket propellant...multiplter: Subscore 3 K ?hvsical State ulriptier Waste Caracteristics Subscore 50 X 1 50 11-1. CS-I HAZARD ASSESSMENT RATING METHODOLOGY FORM (Continued

Detecting changes in tree health and productivity in silver fir-beech forests of Slovenia

Treesearch

N. Torelli; W.C. Shortle; K. Cufar; F. Ferlin; K.T. Smith

1999-01-01

Cambial electrical resistance (CER) was used as an objective measure of vitality of silver fir (Abies alba) in the forests of Slovenia. Trees were rated during the growing season by CER and a subjective crown status index (CSI). Both CER and CSI were inversely correlated to annual ring width increment. Using both CER and CSI, fir were assigned to...

Simulation calculations of efficiencies and silicon consumption for CH3NH3PbI3-x-y Br x Cl y /crystalline silicon tandem solar cells

NASA Astrophysics Data System (ADS)

Zhang, Lili; Xie, Ziang; Tian, Fuyang; Qin, Guogang

2017-04-01

Much attention has been paid to two-subcell tandem solar cells (TSCs) with crystalline silicon (c-Si) as the bottom cell (TSC-Si). Previous works have pointed out that the optimal band gap, E g, of the top cell material for a TSC-Si is around 1.75 eV. With a tunable E g and better stability than MAPbI3 (MA  =  CH3NH3), MAPbI3-x-y Br x Cl y is a promising candidate for the top cell material of a TSC-Si. In this work, calculations concerning the E g, refractive index and extinction coefficient of MAPbI3-x-y Br x Cl y are performed using first-principles calculations including the spin-orbit coupling (SOC) effect. MAPbI3-x-y Br x Cl y with five sets of x and y, which have a E g around 1.75 eV, are obtained. On this basis, absorption of the perovskite top cell is calculated applying the Lambert-Beer model (LBM) and the transfer matrix model (TMM), respectively. Considering the Auger recombination in the c-Si bottom cell and radiation coupling between the two subcells, the efficiencies for MAPbI3-x-y Br x Cl y /c-Si TSCs with the five sets of x and y are calculated. Among them, the MAPbI2.375Br0.5Cl0.125/c-Si TSC achieves the highest efficiency of 35.1% with a 440 nm thick top cell and 50 µm thick c-Si when applying the LBM. When applying the TMM, the highest efficiency of 32.5% is predicted with a 580 nm thick MAPbI2.375Br0.5Cl0.125 top cell and 50 µm thick c-Si. Compared with the limiting efficiency of 27.1% for a 190 µm thick c-Si single junction solar cell (SC), the MAPbI2.375Br0.5Cl0.125/c-Si TSC shows a superior performance of high efficiency and low c-Si consumption.

Fabricating with crystalline Si to improve superconducting detector performance

NASA Astrophysics Data System (ADS)

Beyer, A. D.; Hollister, M. I.; Sayers, J.; Frez, C. F.; Day, P. K.; Golwala, S. R.

2017-05-01

We built and measured radio-frequency (RF) loss tangent, tan δ, evaluation structures using float-zone quality silicon-on-insulator (SOI) wafers with 5 μm thick device layers. Superconducting Nb components were fabricated on both sides of the SOI Si device layer. Our main goals were to develop a robust fabrication for using crystalline Si (c-Si) dielectric layers with superconducting Nb components in a wafer bonding process and to confirm that tan δ with c-Si dielectric layers was reduced at RF frequencies compared to devices fabricated with amorphous dielectrics, such as SiO2 and SixNy, where tan δ ∼ 10-3. Our primary test structure used a Nb coplanar waveguide (CPW) readout structure capacitively coupled to LC resonators, where the capacitors were defined as parallel-plate capacitors on both sides of a c-Si device layer using a wafer bonding process with benzocyclobutene (BCB) wafer bonding adhesive. Our control experiment, to determine the intrinsic tan δ in the SOI device layer without wafer bonding, also used Nb CPW readout coupled to LC resonators; however, the parallel-plate capacitors were fabricated on both sides of the Si device layer using a deep reactive ion etch (DRIE) to access the c-Si underside through the buried oxide and handle Si layers in the SOI wafers. We found that our wafer bonded devices demonstrated F· δ = (8 ± 2) × 10-5, where F is the filling fraction of two-level states (TLS). For the control experiment, F· δ = (2.0 ± 0.6) × 10-5, and we discuss what may be degrading the performance in the wafer bonded devices as compared to the control devices.

Acetylcholine-activated ionic currents in parasympathetic neurons of bullfrog heart.

PubMed

Tateishi, N; Kim, D K; Akaike, N

1990-05-01

1. The electrical and pharmacologic properties of acetylcholine (ACh)-induced current (IACh) were studied in the parasympathetic neurons isolated from bullfrog heart with the use of the concentration-clamp technique, which allows intracellular perfusion and rapid change of external solution within 2 ms under the single-electrode voltage-clamp condition. 2. The IACh consisted of an initial transient peak component and a successive steady-state plateau component. Both currents increased in a sigmoidal fashion with increasing ACh concentration. The dissociation constant (Kd value) and the Hill coefficient for each component were 2.2 X 10(-5) M and 1.6, respectively. 3. In the K(+)-free solution, the reversal potential (EACh) of IACh was close to the Na+ equilibrium potential (ENa). The current-voltage (I-V) relation showed inward rectification at positive potentials. 4. Nicotine mimicked only the peak component of IACh. However both peak and steady-state components were blocked nonselectively by the nicotinic blockers d-tubocurarine and hexamethonium. 5. Carbamylcholine (CCh) mimicked the steady-state component of IACh. The steady-state component was selectively inhibited by atropine at concentrations 1,000 times lower than that required for inhibition of the peak component. The steady state was blocked equally by either pirenzepine (M1 blocker) or AF-DX-116 (M2 blocker). 6. It was concluded that the IACh consisted of a peak component having double exponential activation and inactivation, mediated through the nicotinic actions, and a steady-state component having no inactivation, mediated through the muscarinic action.

Multiple-access relaying with network coding: iterative network/channel decoding with imperfect CSI

NASA Astrophysics Data System (ADS)

Vu, Xuan-Thang; Renzo, Marco Di; Duhamel, Pierre

2013-12-01

In this paper, we study the performance of the four-node multiple-access relay channel with binary Network Coding (NC) in various Rayleigh fading scenarios. In particular, two relay protocols, decode-and-forward (DF) and demodulate-and-forward (DMF) are considered. In the first case, channel decoding is performed at the relay before NC and forwarding. In the second case, only demodulation is performed at the relay. The contributions of the paper are as follows: (1) two joint network/channel decoding (JNCD) algorithms, which take into account possible decoding error at the relay, are developed in both DF and DMF relay protocols; (2) both perfect channel state information (CSI) and imperfect CSI at receivers are studied. In addition, we propose a practical method to forward the relays error characterization to the destination (quantization of the BER). This results in a fully practical scheme. (3) We show by simulation that the number of pilot symbols only affects the coding gain but not the diversity order, and that quantization accuracy affects both coding gain and diversity order. Moreover, when compared with the recent results using DMF protocol, our proposed DF protocol algorithm shows an improvement of 4 dB in fully interleaved Rayleigh fading channels and 0.7 dB in block Rayleigh fading channels.

Designing metal hemispheres on silicon ultrathin film solar cells for plasmonic light trapping.

PubMed

Gao, Tongchuan; Stevens, Erica; Lee, Jung-kun; Leu, Paul W

2014-08-15

We systematically investigate the design of two-dimensional silver (Ag) hemisphere arrays on crystalline silicon (c-Si) ultrathin film solar cells for plasmonic light trapping. The absorption in ultrathin films is governed by the excitation of Fabry-Perot TEMm modes. We demonstrate that metal hemispheres can enhance absorption in the films by (1) coupling light to c-Si film waveguide modes and (2) exciting localized surface plasmon resonances (LSPRs). We show that hemisphere arrays allow light to couple to fundamental TEm and TMm waveguide modes in c-Si film as well as higher-order versions of these modes. The near-field light concentration of LSPRs also may increase absorption in the c-Si film, though these resonances are associated with significant parasitic absorption in the metal. We illustrate how Ag plasmonic hemispheres may be utilized for light trapping with 22% enhancement in short-circuit current density compared with that of a bare 100 nm thick c-Si ultrathin film solar cell.

Deuterium trapping in the carbon-silicon co-deposition layers prepared by RF sputtering in D2 atmosphere

NASA Astrophysics Data System (ADS)

Zhang, Hongliang; Zhang, Weiyuan; Su, Ranran; Tu, Hanjun; Shi, Liqun; Hu, Jiansheng

2018-04-01

Deuterated carbon-silicon layers co-deposited on graphite and silicon substrates by radio frequency magnetron sputtering in pure D2 plasma were produced to study deuterium trapping and characteristics of the C-Si layers. The C-Si co-deposited layers were examined by ion beam analysis (IBA), Raman spectroscopy (RS), infrared absorption (IR) spectroscopy, thermal desorption spectroscopy (TDS) and scanning electron microscopy (SEM). It was found that the growth rate of the C-Si co-deposition layer decreased with increasing temperature from 350 K to 800 K, the D concentration and C/Si ratios increased differently on graphite and silicon substrates. TDS shows that D desorption is mainly as D2, HD, HDO, CD4, and C2D4 and release peaks occurred at temperatures of less than 900 K. RS and IR analysis reveal that the structure of the C-Si layers became more disordered with increasing temperatures. Rounded areas of peeling with 1-2 μm diameters were observed on the surface.

An Investigation on a Crystalline-Silicon Solar Cell with Black Silicon Layer at the Rear.

PubMed

Zhou, Zhi-Quan; Hu, Fei; Zhou, Wen-Jie; Chen, Hong-Yan; Ma, Lei; Zhang, Chi; Lu, Ming

2017-12-15

Crystalline-Si (c-Si) solar cell with black Si (b-Si) layer at the rear was studied in order to develop c-Si solar cell with sub-band gap photovoltaic response. The b-Si was made by chemical etching. The c-Si solar cell with b-Si at the rear was found to perform far better than that of similar structure but with no b-Si at the rear, with the efficiency being increased relatively by 27.7%. This finding was interesting as b-Si had a large specific surface area, which could cause high surface recombination and degradation of solar cell performance. A graded band gap was found to form at the rear of the c-Si solar cell with b-Si layer at the rear. This graded band gap tended to expel free electrons away from the rear, thus reducing the probability of electron-hole recombination at b-Si and improving the performance of c-Si solar cell.

A surfeit of science: The "CSI effect" and the media appropriation of the public understanding of science.

PubMed

Cole, Simon A

2015-02-01

Over the past decade, popular media has promulgated claims that the television program CSI and its spinoffs and imitators have had a pernicious effect on the public understanding of forensic science, the so-called "CSI effect." This paper analyzes those media claims by documenting the ways in which the media claims that CSI "distorts" an imagined "reality." It shows that the media appropriated the analytic stance usually adopted by science advocates, portraying the CSI effect as a social problem in science communication. This appropriation was idiosyncratic in that it posited, as a social problem, a "surfeit" of knowledge and positive imagery about science, rather than the more familiar "deficits." In addition, the media simultaneously appropriated both "traditional" and "critical" PUS discourses. Despite this apparent contradiction, the paper concludes that, in both discourses, the media and its expert informants insist upon their hegemony over "the public" to articulate the "reality" of forensic science. © The Author(s) 2013.

Gating current studies reveal both intra- and extracellular cation modulation of K+ channel deactivation

PubMed Central

Wang, Zhuren; Zhang, Xue; Fedida, David

1999-01-01

The presence of permeant ions can modulate the rate of gating charge return in wild-type human heart K+ (hKv1.5) channels. Here we employ gating current measurements in a non-conducting mutant, W472F, of the hKv1.5 channel to investigate how different cations can modulate charge return and whether the actions can be specifically localized at the internal as well as the external mouth of the channel pore. Intracellular cations were effective at accelerating charge return in the sequence Cs+ > Rb+ > K+ > Na+ > NMG+. Extracellular cations accelerated charge return with the selectivity sequence Cs+ > Rb+ > Na+ = NMG+. Intracellular and extracellular cation actions were of relatively low affinity. The Kd for preventing slowing of the time constant of the off-gating current decay (τoff) was 20.2 mM for intracellular Cs+ (Csi+) and 358 mM for extracellular Cs+ (Cso+). Both intracellular and extracellular cations can regulate the rate of charge return during deactivation of hKv1.5, but intracellular cations are more effective. We suggest that ion crystal radius is an important determinant of this action, with larger ions preventing slowing more effectively. Important parallels exist with cation-dependent modulation of slow inactivation of ionic currents in this channel. However, further experiments are required to understand the exact relationship between acceleration of charge return and the slowing of inactivation of ionic currents by cations. PMID:10050001

Inhibition of human Na(v)1.5 sodium channels by strychnine and its analogs.

PubMed

Yuan, Chunhua; Sun, Lirong; Zhang, Meng; Li, Shuji; Wang, Xuemin; Gao, Tianming; Zhu, Xinhong

2011-08-15

Strychnine and brucine from the seeds of the plant Strychnos nux vomica have been shown to have interesting pharmacological effects on several neurotransmitter receptors. In this study, we have characterized the pharmacological properties of strychnine and its analogs on human Na(v)1.5 channels to assess their potential therapeutic advantage in certain arrhythmias. Among the eight alkaloids, only strychnine and icajine exhibited inhibition potency on the Na(v)1.5 channel with the half-maximum inhibition (IC(50)) values of 83.1μM and 104.6μM, respectively. Structure-function analysis indicated that the increased bulky methoxy groups on the phenyl ring or the negatively charged oxygen atom may account for this lack of inhibition on the Na(v)1.5 channel. Strychnine and icajine may bind to the channel by cation-π interactions. The substitution with a large side chain on the phenyl ring or the increased molecular volume may alter the optimized position for the compound close to the binding sites of the channel. Strychnine and icajine bind to the Na(v)1.5 channel with a new mechanism that is different from TTX and local anesthetics. They bind to the outer vestibule of the channel pore with fast association and dissociation rates at resting state. Strychnine and icajine had little effect on steady-state fast inactivation but markedly shifted the slow inactivation of Na(v)1.5 currents toward more hyperpolarized potentials. The property of icajine influencing slow-inactivated state of Na(v)1.5 channel would be potential therapeutic advantages in certain arrhythmias. Copyright © 2011 Elsevier Inc. All rights reserved.

Expedition 21 FE Thirsk installs the new CSI-03

NASA Image and Video Library

2009-11-18

ISS021-E-029873 (18 Nov. 2009) --- Canadian Space Agency astronaut Robert Thirsk, Expedition 21 flight engineer, works with the new Commercial Generic Bioprocessing Apparatus (CGBA) Science Insert 03 (CSI-03) assembly in the Kibo laboratory of the International Space Station. CSI-03 is flying two butterfly habitats during this mission and will examine the complete life cycle of the butterflies as they eat, grow and undergo metamorphosis in space.

Expedition 21 FE Thirsk installs the new CSI-03

NASA Image and Video Library

2009-11-18

ISS021-E-029871 (18 Nov. 2009) --- Canadian Space Agency astronaut Robert Thirsk, Expedition 21 flight engineer, works with the new Commercial Generic Bioprocessing Apparatus (CGBA) Science Insert 03 (CSI-03) assembly in the Kibo laboratory of the International Space Station. CSI-03 is flying two butterfly habitats during this mission and will examine the complete life cycle of the butterflies as they eat, grow and undergo metamorphosis in space.

Impaired cellulose synthase guidance leads to stem torsion and twists phyllotactic patterns in Arabidopsis.

PubMed

Landrein, Benoît; Lathe, Rahul; Bringmann, Martin; Vouillot, Cyril; Ivakov, Alexander; Boudaoud, Arezki; Persson, Staffan; Hamant, Olivier

2013-05-20

The parallel alignment of stiff cellulose microfibrils in plant-cell walls mediates anisotropic growth. This is largely controlled by cortical microtubules, which drive the insertion and trajectory of the cellulose synthase (CESA) complex at the plasma membrane. The CESA interactive protein 1 (CSI1) acts as a physical linker between CESA and cortical microtubules. Here we show that the inflorescence stems of csi1 mutants exhibit subtle right-handed torsion. Because cellulose deposition is largely uncoupled from cortical microtubules in csi1, we hypothesize that strictly transverse deposition of microfibrils in the wild-type is replaced by a helical orientation of uniform handedness in the mutant and that the helical microfibril alignment generates torsion. Interestingly, both elastic and viscous models for an expanding cell predict that a net helical orientation of microfibrils gives rise to a torque. We indeed observed tilted microfibrils in csi1 cells, and the torsion was almost absent in a csi1 prc1 background with impaired cellulose synthesis. In addition, the stem torsion led to a novel bimodal and robust phyllotactic pattern in the csi1 mutant, illustrating how growth perturbations can replace one robust mathematical pattern with a different, equally robust pattern. Copyright © 2013 Elsevier Ltd. All rights reserved.

Automated choroidal segmentation method in human eye with 1050nm optical coherence tomography

NASA Astrophysics Data System (ADS)

Liu, Cindy; Wang, Ruikang K.

2014-02-01

Choroidal thickness (ChT), defined as the distance between the retinal pigment epithelium (RPE) and the choroid-sclera interface (CSI), is highly correlated with various ocular disorders like high myopia, diabetic retinopathy, and central serous chorioretinopathy. Long wavelength Optical Coherence Tomography (OCT) has the ability to penetrate deep to the CSI, making the measurement of the ChT possible. The ability to accurately segment the CSI and RPE is important in extracting clinical information. However, automated CSI segmentation is challenging due to the weak boundary in the lower choroid and inconsistent texture with varied blood vessels. We propose a K-means clustering based automated algorithm, which is effective in segmenting the CSI and RPE. The performance of the method was evaluated using 531 frames from 4 normal subjects. The RPE and CSI segmentation time was about 0.3 seconds per frame, and the average time was around 0.5 seconds per frame with correction among frames, which is faster than reported algorithms. The results from the proposed method are consistent with the manual segmentation results. Further investigation includes the optimization of the algorithm to cover more OCT images captured from patients and the increase of the processing speed and robustness of the segmentation method.

Observation and experimental investigation of confinement effects on ion transport and electrokinetic flows at the microscale

PubMed Central

Benneker, Anne M.; Wood, Jeffery A.; Tsai, Peichun A.; Lammertink, Rob G. H.

2016-01-01

Electrokinetic effects adjacent to charge-selective interfaces (CSI) have been experimentally investigated in microfluidic platforms in order to gain understanding on underlying phenomena of ion transport at elevated applied voltages. We experimentally investigate the influence of geometry and multiple array densities of the CSI on concentration and flow profiles in a microfluidic set-up using nanochannels as the CSI. Particle tracking obtained under chronoamperometric measurements show the development of vortices in the microchannel adjacent to the nanochannels. We found that the direction of the electric field and the potential drop inside the microchannel has a large influence on the ion transport through the interface, for example by inducing immediate wall electroosmotic flow. In microfluidic devices, the electric field may not be directed normal to the interface, which can result in an inefficient use of the CSI. Multiple vortices are observed adjacent to the CSI, growing in size and velocity as a function of time and dependent on their location in the microfluidic device. Local velocities inside the vortices are measured to be more than 1.5 mm/s. Vortex speed, as well as flow speed in the channel, are dependent on the geometry of the CSI and the distance from the electrode. PMID:27853257

Enhancement in c-Si solar cells using 16 nm InN nanoparticles

NASA Astrophysics Data System (ADS)

Imtiaz Chowdhury, Farsad; Alnuaimi, Aaesha; Alkis, Sabri; Ortaç, Bülend; Aktürk, Selçuk; Alevli, Mustafa; Dietz, Nikolaus; Kemal Okyay, Ali; Nayfeh, Ammar

2016-05-01

In this work, 16 nm indium nitride (InN) nanoparticles (NPs) are used to increase the performance of thin-film c-Si HIT solar cells. InN NPs were spin-coated on top of an ITO layer of c-Si HIT solar cells. The c-Si HIT cell is a stack of 2 μm p type c-Si, 4-5 nm n type a-Si, 15 nm n+ type a-Si and 80 nm ITO grown on a p+ type Si substrate. On average, short circuit current density (Jsc) increases from 19.64 mA cm-2 to 21.54 mA cm-2 with a relative improvement of 9.67% and efficiency increases from 6.09% to 7.09% with a relative improvement of 16.42% due to the presence of InN NPs. Reflectance and internal/external quantum efficiency (IQE/EQE) of the devices were also measured. Peak EQE was found to increase from 74.1% to 81.3% and peak IQE increased from 93% to 98.6% for InN NPs coated c-Si HIT cells. Lower reflection of light due to light scattering is responsible for performance enhancement between 400-620 nm while downshifted photons are responsible for performance enhancement from 620 nm onwards.

Spectroellipsometric detection of silicon substrate damage caused by radiofrequency sputtering of niobium oxide

NASA Astrophysics Data System (ADS)

Lohner, Tivadar; Serényi, Miklós; Szilágyi, Edit; Zolnai, Zsolt; Czigány, Zsolt; Khánh, Nguyen Quoc; Petrik, Péter; Fried, Miklós

2017-11-01

Substrate surface damage induced by deposition of metal atoms by radiofrequency (rf) sputtering or ion beam sputtering onto single-crystalline silicon (c-Si) surface has been characterized earlier by electrical measurements. The question arises whether it is possible to characterize surface damage using spectroscopic ellipsometry (SE). In our experiments niobium oxide layers were deposited by rf sputtering on c-Si substrates in gas mixture of oxygen and argon. Multiple angle of incidence spectroscopic ellipsometry measurements were performed, a four-layer optical model (surface roughness layer, niobium oxide layer, native silicon oxide layer and ion implantation-amorphized silicon [i-a-Si] layer on a c-Si substrate) was created in order to evaluate the spectra. The evaluations yielded thicknesses of several nm for the i-a-Si layer. Better agreement could be achieved between the measured and the generated spectra by inserting a mixed layer (with components of c-Si and i-a-Si applying the effective medium approximation) between the silicon oxide layer and the c-Si substrate. High depth resolution Rutherford backscattering (RBS) measurements were performed to investigate the interface disorder between the deposited niobium oxide layer and the c-Si substrate. Atomic resolution cross-sectional transmission electron microscopy investigation was applied to visualize the details of the damaged subsurface region of the substrate.

Examination of the "CSI Effect" on Perceptions of Scientific and Testimonial Evidence in a Hong Kong Chinese Sample.

PubMed

Hui, Cora Y T; Lo, T Wing

2017-05-01

Television is a powerful medium through which to convey information and messages to the public. The recent proliferation of forensic science and criminal justice information throughout all forms of media, coupled with raised expectations toward forensic evidence, has led some to suspect that a "CSI effect" ( Crime Scene Investigation effect) is taking place. The present study contributes to the literature addressing the CSI effect in two ways. First, it examines whether the CSI effect exists in the Chinese population of Hong Kong. Second, using a mock-jury paradigm, it empirically examines a more integrative perspective of the CSI effect. It was found that, although the amount of media coverage involving forensic evidence does influence participants' perception of legal evidence to some degree, such a perception does not affect participants' legal decision making. Viewers of forensic dramas were not more likely to convict the defendant when forensic evidence was presented and not less likely to convict when only testimonial evidence was presented. The only significant predictor of the defendant's culpability when scientific evidence was presented was participants' ratings of the reliability of scientific evidence. Results from the present study lend no support to the existence of the CSI effect in Hong Kong.

Realization of 13.6% Efficiency on 20 μm Thick Si/Organic Hybrid Heterojunction Solar Cells via Advanced Nanotexturing and Surface Recombination Suppression.

PubMed

He, Jian; Gao, Pingqi; Liao, Mingdun; Yang, Xi; Ying, Zhiqin; Zhou, Suqiong; Ye, Jichun; Cui, Yi

2015-06-23

Hybrid silicon/polymer solar cells promise to be an economically feasible alternative energy solution for various applications if ultrathin flexible crystalline silicon (c-Si) substrates are used. However, utilization of ultrathin c-Si encounters problems in light harvesting and electronic losses at surfaces, which severely degrade the performance of solar cells. Here, we developed a metal-assisted chemical etching method to deliver front-side surface texturing of hierarchically bowl-like nanopores on 20 μm c-Si, enabling an omnidirectional light harvesting over the entire solar spectrum as well as an enlarged contact area with the polymer. In addition, a back surface field was introduced on the back side of the thin c-Si to minimize the series resistance losses as well as to suppress the surface recombination by the built high-low junction. Through these improvements, a power conversion efficiency (PCE) up to 13.6% was achieved under an air mass 1.5 G irradiation for silicon/organic hybrid solar cells with the c-Si thickness of only about 20 μm. This PCE is as high as the record currently reported in hybrid solar cells constructed from bulk c-Si, suggesting a design rule for efficient silicon/organic solar cells with thinner absorbers.

Digital transceiver design for two-way AF-MIMO relay systems with imperfect CSI

NASA Astrophysics Data System (ADS)

Hu, Chia-Chang; Chou, Yu-Fei; Chen, Kui-He

2013-09-01

In the paper, combined optimization of the terminal precoders/equalizers and single-relay precoder is proposed for an amplify-and-forward (AF) multiple-input multiple-output (MIMO) two-way single-relay system with correlated channel uncertainties. Both terminal transceivers and relay precoding matrix are designed based on the minimum mean square error (MMSE) criterion when terminals are unable to erase completely self-interference due to imperfect correlated channel state information (CSI). This robust joint optimization problem of beamforming and precoding matrices under power constraints belongs to neither concave nor convex so that a nonlinear matrix-form conjugate gradient (MCG) algorithm is applied to explore local optimal solutions. Simulation results show that the robust transceiver design is able to overcome effectively the loss of bit-error-rate (BER) due to inclusion of correlated channel uncertainties and residual self-interference.

OLYMPEX Counterflow Spectrometer and Impactor Field Campaign Report

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

Poellot, Michael

The U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility’s ARM Aerial Facility (AAF) Counterflow Spectrometer and Impactor (CSI) probe was flown on the University of North Dakota Cessna Citation research aircraft during the Olympic Mountain Experiment (OLYMPEX). The field campaign took place from November 12 through December 19, 2015, over the Olympic Mountains and coastal waters of Washington State as part of a National Aeronautics and Space Administration (NASA) Global Precipitation Measurement (GPM) validation campaign. The CSI was added to the Citation instrument suite to support the NASA Aerosol-Cloud Ecosystem (ACE) satellite program and flights ofmore » the NASA Lockheed Earth Resources (ER-2) aircraft. ACE funded extra ER-2 flights to focus on clouds that are weakly precipitating, which are also of interest to the DOE Atmospheric System Research (ASR) program.« less

Thyroid-Stimulating Hormone Suppression for Protection Against Hypothyroidism Due to Craniospinal Irradiation for Childhood Medulloblastoma/Primitive Neuroectodermal Tumor

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

Massimino, Maura; Gandola, Lorenza; Collini, Paola

Purpose: Hypothyroidism is one of the earliest endocrine effects of craniospinal irradiation (CSI). The effects of radiation also depend on circulating thyroid-stimulating hormone (TSH), which acts as an indicator of thyrocyte function and is the most sensitive marker of thyroid damage. Hence, our study was launched in 1998 to evaluate the protective effect of TSH suppression during CSI for medulloblastoma/primitive neuroectodermal tumor. Patients and Methods: From Jan 1998 to Feb 2001, a total of 37 euthyroid children scheduled for CSI for medulloblastoma/primitive neuroectodermal tumor underwent thyroid ultrasound and free triiodothyronine (FT3), free thyroxine (FT4), and TSH evaluation at the beginningmore » and end of CSI. From 14 days before and up to the end of CSI, patients were administered L-thyroxine at suppressive doses; every 3 days, TSH suppression was checked to ensure a value <0.3 {mu}M/ml. During follow-up, blood tests and ultrasound were repeated after 1 year; primary hypothyroidism was considered an increased TSH level greater than normal range. CSI was done using a hyperfractionated accelerated technique with total doses ranging from 20.8-39 Gy; models were used to evaluate doses received by the thyroid bed. Results: Of 37 patients, 25 were alive a median 7 years after CSI. They were well matched for all clinical features, except that eight children underwent adequate TSH suppression during CSI, whereas 17 did not. Hypothyroidism-free survival rates were 70% for the 'adequately TSH-suppressed' group and 20% for the 'inadequately TSH-suppressed' group (p = 0.02). Conclusions: Thyroid-stimulating hormone suppression with L-thyroxine had a protective effect on thyroid function at long-term follow-up. This is the first demonstration that transient endocrine suppression of thyroid activity may protect against radiation-induced functional damage.« less

Ultrasonography and clinical outcome comparison of extracorporeal shock wave therapy and corticosteroid injections for chronic plantar fasciitis: A randomized controlled trial

PubMed Central

Lai, Ta-Wei; Ma, Hsiao-Li; Lee, Meng-Shiunn; Chen, Po-Ming; Ku, Ming-Chou

2018-01-01

Objectives: Extracorporeal shockwave therapy (ESWT) and corticosteroid injection (CSI) are treatment options for plantar fasciitis. Their clinical outcome comparison remains a debate. Also, the thickness changes of the plantar fascia on objective evaluation under the medium energy ESWT and CSI therapy are elusive. Methods: A total of 97 patients with chronic plantar fasciitis were enrolled in the randomized prospective trial. Forty-seven patients received extracorporeal shock wave therapy (ESWT), and fifty patients received corticosteroid injection (CSI). The thickness of the plantar fascia was evaluated respectively before ESWT and CSI, and at the 4th and 12th week after ESWT and CSI by ultrasonography. Pain level and clinical outcomes were recorded using visual analogue scale (VAS) and 100-points scoring systems. Correlation analysis was performed between the thickness change and clinical outcome. Results: Under ultrasonography, we observed more increase of plantar fascia thickness of ESWT group than CSI group at 4th week (p=0.048). VAS of plantar fasciitis patients receiving ESWT was lower than those who received corticosteroid injection (0.001 and p<0.001, at 4th and 12th week). On the assessment of 100-points scoring systems, the pain level of patients with ESWT was lower than those with CSI at the 12th week (p<0.001). On the other hand, the increase of plantar fascia thickness at 4th week was positively correlated with the decrease of VAS score at 12th week follow-up (R=0.302, P=0.039). Conclusions: At 4th week after treatment, the thickness of plantar fascia increased. Then it decreased gradually, but not to the baseline at 12th week. On the pain level outcome at 12th week, extracorporeal shockwave therapy (ESWT) was more efficient than corticosteroid injection (CSI) on chronic plantar fasciitis. The more change of plantar fascia after ESWT, the more efficient on clinical outcome. PMID:29504578

Ultrasonography and clinical outcome comparison of extracorporeal shock wave therapy and corticosteroid injections for chronic plantar fasciitis: A randomized controlled trial.

PubMed

Lai, Ta-Wei; Ma, Hsiao-Li; Lee, Meng-Shiunn; Chen, Po-Ming; Ku, Ming-Chou

2018-03-01

Extracorporeal shockwave therapy (ESWT) and corticosteroid injection (CSI) are treatment options for plantar fasciitis. Their clinical outcome comparison remains a debate. Also, the thickness changes of the plantar fascia on objective evaluation under the medium energy ESWT and CSI therapy are elusive. A total of 97 patients with chronic plantar fasciitis were enrolled in the randomized prospective trial. Forty-seven patients received extracorporeal shock wave therapy (ESWT), and fifty patients received corticosteroid injection (CSI). The thickness of the plantar fascia was evaluated respectively before ESWT and CSI, and at the 4 th and 12 th week after ESWT and CSI by ultrasonography. Pain level and clinical outcomes were recorded using visual analogue scale (VAS) and 100-points scoring systems. Correlation analysis was performed between the thickness change and clinical outcome. Under ultrasonography, we observed more increase of plantar fascia thickness of ESWT group than CSI group at 4 th week (p=0.048). VAS of plantar fasciitis patients receiving ESWT was lower than those who received corticosteroid injection (0.001 and p⟨0.001, at 4 th and 12 th week). On the assessment of 100-points scoring systems, the pain level of patients with ESWT was lower than those with CSI at the 12 th week (p⟨0.001). On the other hand, the increase of plantar fascia thickness at 4 th week was positively correlated with the decrease of VAS score at 12 th week follow-up (R=0.302, P=0.039). At 4 th week after treatment, the thickness of plantar fascia increased. Then it decreased gradually, but not to the baseline at 12 th week. On the pain level outcome at 12 th week, extracorporeal shockwave therapy (ESWT) was more efficient than corticosteroid injection (CSI) on chronic plantar fasciitis. The more change of plantar fascia after ESWT, the more efficient on clinical outcome.

Recipient’s Genetic R702W NOD2 Variant Is Associated with an Increased Risk of Bacterial Infections after Orthotopic Liver Transplantation

PubMed Central

van Hoek, Bart; van den Berg, Arie P.; Porte, Robert J.; Blokzijl, Hans; Coenraad, Minneke J.; Hepkema, Bouke G.; Schaapherder, Alexander F.; Ringers, Jan; Weersma, Rinse K.; Verspaget, Hein W.

2013-01-01

Introduction Orthotopic liver transplantation (OLT) is accompanied by a significant postoperative infection risk. Immunosuppression to prevent rejection increases the susceptibility to infections, mainly by impairing the adaptive immune system. Genetic polymorphisms in the lectin complement pathway of the donor have recently been identified as important risk determinants of clinically significant bacterial infection (CSI) after OLT. Another genetic factor involved in innate immunity is NOD2, which was reported to be associated with increased risk of spontaneous bacterial peritonitis in cirrhotic patients. Methods We assessed association of three genetic NOD2 variants (R702W, G908R and 3020insC) with increased risk of CSI after OLT. 288 OLT recipient-donor pairs from two tertiary referral centers were genotyped for the three NOD2 variants. The probability of CSI in relation to NOD2 gene variants was determined with cumulative incidence curves and log-rank analysis. Results The R702W NOD2 variant in the recipient was associated with CSI after OLT. Eight out of 15 (53.3%) individuals with a mutated genotype compared to 80/273 (29.3%) with wild type genotype developed CSI (p=0.027, univariate cox regression), illustrated by a higher frequency of CSI after OLT over time (p=0.0003, log rank analysis). Multivariate analysis (including the donor lectin complement pathway profile) showed independence of this R702W NOD2 association from other risk factors (HR 2.0; p=0.04). The other NOD2 variants, G908R and 3020insC, in the recipient were not associated with CSI. There was no association with CSI after OLT for any of the NOD2 variants in the donor. Conclusion The mutated NOD2 R702W genotype in the recipient is independently associated with an increased risk of bacterial infections after liver transplantation, indicating a predisposing role for this genetic factor impairing the recipient’s innate immune system. PMID:23977330

Eslicarbazepine and the enhancement of slow inactivation of voltage-gated sodium channels: a comparison with carbamazepine, oxcarbazepine and lacosamide.

PubMed

Hebeisen, Simon; Pires, Nuno; Loureiro, Ana I; Bonifácio, Maria João; Palma, Nuno; Whyment, Andrew; Spanswick, David; Soares-da-Silva, Patrício

2015-02-01

This study aimed at evaluating the effects of eslicarbazepine, carbamazepine (CBZ), oxcarbazepine (OXC) and lacosamide (LCM) on the fast and slow inactivated states of voltage-gated sodium channels (VGSC). The anti-epileptiform activity was evaluated in mouse isolated hippocampal slices. The anticonvulsant effects were evaluated in MES and the 6-Hz psychomotor tests. The whole-cell patch-clamp technique was used to investigate the effects of eslicarbazepine, CBZ, OXC and LCM on sodium channels endogenously expressed in N1E-115 mouse neuroblastoma cells. CBZ and eslicarbazepine exhibit similar concentration dependent suppression of epileptiform activity in hippocampal slices. In N1E-115 mouse neuroblastoma cells, at a concentration of 250 μM, the voltage dependence of the fast inactivation was not influenced by eslicarbazepine, whereas LCM, CBZ and OXC shifted the V0.5 value (mV) by -4.8, -12.0 and -16.6, respectively. Eslicarbazepine- and LCM-treated fast-inactivated channels recovered similarly to control conditions, whereas CBZ- and OXC-treated channels required longer pulses to recover. CBZ, eslicarbazepine and LCM shifted the voltage dependence of the slow inactivation (V0.5, mV) by -4.6, -31.2 and -53.3, respectively. For eslicarbazepine, LCM, CBZ and OXC, the affinity to the slow inactivated state was 5.9, 10.4, 1.7 and 1.8 times higher than to the channels in the resting state, respectively. In conclusion, eslicarbazepine did not share with CBZ and OXC the ability to alter fast inactivation of VGSC. Both eslicarbazepine and LCM reduce VGSC availability through enhancement of slow inactivation, but LCM demonstrated higher interaction with VGSC in the resting state and with fast inactivation gating. Copyright © 2014 Elsevier Ltd. All rights reserved.

Preparation of reflective CsI photocathodes with reproducible high quantum efficiency

NASA Astrophysics Data System (ADS)

Maier-Komor, P.; Bauer, B. B.; Friese, J.; Gernhäuser, R.; Kienle, P.; Körner, H. J.; Montermann, G.; Zeitelhack, K.

1995-02-01

CsI as a solid UV-photocathode material has many promising applications in fast gaseous photon detectors. They are proposed in large area Ring Imaging CHerenkov (RICH) devices in forthcoming experiments at various high-energy particle accelerators. A high photon-to-electron conversion efficiency is a basic requirement for the successful operation of these devices. High reproducible quantum efficiencies could be achieved with CsI layers prepared by electron beam evaporation from a water-cooled copper crucible. CsI films were deposited in the thickness range of 30 to 500 μg/cm 2. Absorption coefficients and quantum efficiencies were measured in the wavelength region of 150 nm to 250 nm. The influence of various evaporation parameters on the quantum efficiency were investigated.

Colloquium Spectroscopicum Internationale XL, Pisa (Italy), 11-16 June 2017

NASA Astrophysics Data System (ADS)

D'Ulivo, Alessandro; Legnaioli, Stefano

2017-12-01

The 40th edition of the Colloquium Spectroscopicum Internationale (CSI XL) was held in Pisa (Italy) between 11 and 16 June 2017, at the Congress Center of Pisa. It is the third time that this prestigious conference on Analytical Spectroscopy is organized in Italy after the CSI II (Venice, 1951) and CSI XVII (Florence, 1973). In this occasion, the CSI XL took place together with the 9th Euro-Mediterranean Symposium on Laser Induced Breakdown spectroscopy (IX EMSLIBS, Chaired by Vincenzo Palleschi) with the aim to have a positive impact on both conferences by fostering synergisms among participants of all ages, as well as the level of participation, in the stimulating atmosphere of a beautiful city of art in Tuscany.

Generation kinetics of boron-oxygen complexes in p-type compensated c-Si

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

Wu, Yichao; Yu, Xuegong, E-mail: yuxuegong@zju.edu.cn; Chen, Peng

2014-03-10

Kinetics characteristics of boron-oxygen complexes responsible for light-induced degradation in p-type compensated c-Si have been investigated. The generation of B-O complexes is well fitted by a fast-forming process and a slow-forming one. Activation energies of complexes generation during the fast-forming process are determined to be 0.29 and 0.24 eV in compensated and non-compensated c-Si, respectively, and those during the slow-forming process are the same, about 0.44 eV. Moreover, it is found that the pre-exponential factors of complexes generation in compensated c-Si is proportional to the square of the net doping concentration, which suggests that the latent centers should exist.

Local anesthetic and antiepileptic drug access and binding to a bacterial voltage-gated sodium channel

PubMed Central

Boiteux, Céline; Vorobyov, Igor; French, Robert J.; French, Christopher; Yarov-Yarovoy, Vladimir; Allen, Toby W.

2014-01-01

Voltage-gated sodium (Nav) channels are important targets in the treatment of a range of pathologies. Bacterial channels, for which crystal structures have been solved, exhibit modulation by local anesthetic and anti-epileptic agents, allowing molecular-level investigations into sodium channel-drug interactions. These structures reveal no basis for the “hinged lid”-based fast inactivation, seen in eukaryotic Nav channels. Thus, they enable examination of potential mechanisms of use- or state-dependent drug action based on activation gating, or slower pore-based inactivation processes. Multimicrosecond simulations of NavAb reveal high-affinity binding of benzocaine to F203 that is a surrogate for FS6, conserved in helix S6 of Domain IV of mammalian sodium channels, as well as low-affinity sites suggested to stabilize different states of the channel. Phenytoin exhibits a different binding distribution owing to preferential interactions at the membrane and water–protein interfaces. Two drug-access pathways into the pore are observed: via lateral fenestrations connecting to the membrane lipid phase, as well as via an aqueous pathway through the intracellular activation gate, despite being closed. These observations provide insight into drug modulation that will guide further developments of Nav inhibitors. PMID:25136136

Characterization of a clinical unit for digital radiography based on irradiation side sampling technology

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

Rivetti, Stefano; Lanconelli, Nico; Bertolini, Marco

2013-10-15

Purpose: A characterization of a clinical unit for digital radiography (FUJIFILM FDR D-EVO) is presented. This system is based on the irradiation side sampling (ISS) technology and can be equipped with two different scintillators: one traditional gadolinium-oxysulphide phosphor (GOS) and a needle structured cesium iodide (CsI) phosphor panel.Methods: The characterization was achieved in terms of response curve, modulation transfer function (MTF), noise power spectra (NPS), detective quantum efficiency (DQE), and psychophysical parameters (contrast-detail analysis with an automatic reading of CDRAD images). For both scintillation screens the authors accomplished the measurements with four standard beam conditions: RAQ3, RQA5, RQA7, and RQA9.Results:more » At the Nyquist frequency (3.33 lp/mm) the MTF is about 35% and 25% for CsI and GOS detectors, respectively. The CsI scintillator has better noise properties than the GOS screen in almost all the conditions. This is particularly true for low-energy beams, where the noise for the GOS system can go up to a factor 2 greater than that found for CsI. The DQE of the CsI detector reaches a peak of 60%, 60%, 58%, and 50% for the RQA3, RQA5, RQA7, and RQA9 beams, respectively, whereas for the GOS screen the maximum DQE is 40%, 44%, 44%, and 35%. The contrast-detail analysis confirms that in the majority of cases the CsI scintillator is able to provide improved outcomes to those obtained with the GOS screen.Conclusions: The limited diffusion of light produced by the ISS reading makes possible the achievement of very good spatial resolution. In fact, the MTF of the unit with the CsI panel is only slightly lower to that achieved with direct conversion detectors. The combination of very good spatial resolution, together with the good noise properties reached with the CsI screen, allows achieving DQE on average about 1.5 times greater than that obtained with GOS. In fact, the DQE of unit equipped with CsI is comparable to the best alternative methods available which are based on the same technology, and similar to others based on an a-Se direct conversion detectors.« less

Inactivation of human interferon by body fluids

NASA Technical Reports Server (NTRS)

Cesario, T. C.; Mandell, A.; Tilles, J. G.

1973-01-01

Description of the effects of human feces, bile, saliva, serum, and cerebrospinal fluid on interferon activity. It is shown that crude interferon is inactivated by at least 50% more than with the control medium used, when incubated for 4 hr in vitro in the presence of serum, saliva, or cerebrospinal liquid, and by close to 100% when incubated with stool extract or bile.

Adjuvant chemotherapy and overall survival in adult medulloblastoma.

PubMed

Kann, Benjamin H; Lester-Coll, Nataniel H; Park, Henry S; Yeboa, Debra N; Kelly, Jacqueline R; Baehring, Joachim M; Becker, Kevin P; Yu, James B; Bindra, Ranjit S; Roberts, Kenneth B

2017-02-01

Although chemotherapy is used routinely in pediatric medulloblastoma (MB) patients, its benefit for adult MB is unclear. We evaluated the survival impact of adjuvant chemotherapy in adult MB. Using the National Cancer Data Base, we identified patients aged 18 years and older who were diagnosed with MB in 2004-2012 and underwent surgical resection and adjuvant craniospinal irradiation (CSI). Patients were divided into those who received adjuvant CSI and chemotherapy (CRT) or CSI alone (RT). Predictors of CRT compared with RT were evaluated with univariable and multivariable logistic regression. Survival analysis was limited to patients receiving CSI doses between 23 and 36 Gy. Overall survival (OS) was evaluated using the Kaplan-Meier estimator, log-rank test, multivariable Cox proportional hazards modeling, and propensity score matching. Of the 751 patients included, 520 (69.2%) received CRT, and 231 (30.8%) received RT. With median follow-up of 5.0 years, estimated 5-year OS was superior in patients receiving CRT versus RT (86.1% vs 71.6%, P < .0001). On multivariable analysis, after controlling for risk factors, CRT was associated with superior OS compared with RT (HR: 0.53; 95%CI: 0.32-0.88, P = .01). On planned subgroup analyses, the 5 year OS of patients receiving CRT versus RT was improved for M0 patients (P < .0001), for patients receiving 36 Gy CSI (P = .0007), and for M0 patients receiving 36 Gy CSI (P = .0008). This national database analysis demonstrates that combined postoperative chemotherapy and radiotherapy are associated with superior survival for adult MB compared with radiotherapy alone, even for M0 patients who receive high-dose CSI. © The Author(s) 2016. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Magnetic resonance Spectroscopy with Linear Algebraic Modeling (SLAM) for higher speed and sensitivity

PubMed Central

Zhang, Yi; Gabr, Refaat E.; Schär, Michael; Weiss, Robert G.; Bottomley, Paul A.

2012-01-01

Speed and signal-to-noise ratio (SNR) are critical for localized magnetic resonance spectroscopy (MRS) of low-concentration metabolites. Matching voxels to anatomical compartments a priori yields better SNR than the spectra created by summing signals from constituent chemical-shift-imaging (CSI) voxels post-acquisition. Here, a new method of localized Spectroscopy using Linear Algebraic Modeling (SLAM) is presented, that can realize this additional SNR gain. Unlike prior methods, SLAM generates spectra from C signal-generating anatomic compartments utilizing a CSI sequence wherein essentially only the C central k-space phase-encoding gradient steps with highest SNR are retained. After MRI-based compartment segmentation, the spectra are reconstructed by solving a sub-set of linear simultaneous equations from the standard CSI algorithm. SLAM is demonstrated with one-dimensional CSI surface coil phosphorus MRS in phantoms, the human leg and the heart on a 3T clinical scanner. Its SNR performance, accuracy, sensitivity to registration errors and inhomogeneity, are evaluated. Compared to one-dimensional CSI, SLAM yielded quantitatively the same results 4-times faster in 24 cardiac patients and healthy subjects. SLAM is further extended with fractional phase-encoding gradients that optimize SNR and/or minimize both inter- and intra-compartmental contamination. In proactive cardiac phosphorus MRS of 6 healthy subjects, both SLAM and fractional-SLAM (fSLAM) produced results indistinguishable from CSI while preserving SNR gains of 36–45% in the same scan-time. Both SLAM and fSLAM are simple to implement and reduce the minimum scan-time for CSI, which otherwise limits the translation of higher SNR achievable at higher field strengths to faster scanning. PMID:22578557

In vivo three-dimensional molecular imaging with Biosensor Imaging of Redundant Deviation in Shifts (BIRDS) at high spatiotemporal resolution.

PubMed

Coman, Daniel; de Graaf, Robin A; Rothman, Douglas L; Hyder, Fahmeed

2013-11-01

Spectroscopic signals which emanate from complexes between paramagnetic lanthanide (III) ions (e.g. Tm(3+)) and macrocyclic chelates (e.g. 1,4,7,10-tetramethyl-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate, or DOTMA(4-)) are sensitive to physiology (e.g. temperature). Because nonexchanging protons from these lanthanide-based macrocyclic agents have relaxation times on the order of a few milliseconds, rapid data acquisition is possible with chemical shift imaging (CSI). Thus, Biosensor Imaging of Redundant Deviation in Shifts (BIRDS) which originate from nonexchanging protons of these paramagnetic agents, but exclude water proton detection, can allow molecular imaging. Previous two-dimensional CSI experiments with such lanthanide-based macrocyclics allowed acquisition from ~12-μL voxels in rat brain within 5 min using rectangular encoding of k space. Because cubical encoding of k space in three dimensions for whole-brain coverage increases the CSI acquisition time to several tens of minutes or more, a faster CSI technique is required for BIRDS to be of practical use. Here, we demonstrate a CSI acquisition method to improve three-dimensional molecular imaging capabilities with lanthanide-based macrocyclics. Using TmDOTMA(-), we show datasets from a 20 × 20 × 20-mm(3) field of view with voxels of ~1 μL effective volume acquired within 5 min (at 11.7 T) for temperature mapping. By employing reduced spherical encoding with Gaussian weighting (RESEGAW) instead of cubical encoding of k space, a significant increase in CSI signal is obtained. In vitro and in vivo three-dimensional CSI data with TmDOTMA(-), and presumably similar lanthanide-based macrocyclics, suggest that acquisition using RESEGAW can be used for high spatiotemporal resolution molecular mapping with BIRDS. Copyright © 2013 John Wiley & Sons, Ltd.

Comparison of accelerated 3-D spiral chemical shift imaging and single-voxel spectroscopy at 3T in the pediatric age group.

PubMed

Yazbek, Sandrine; Prabhu, Sanjay P; Connaughton, Pauline; Grant, Patricia E; Gagoski, Borjan

2015-08-01

Single-voxel spectroscopy (SVS) is usually used in the pediatric population when a short acquisition time is crucial. To overcome the long acquisition time of 3-D phase-encoded chemical shift imaging (CSI) and lack of spatial coverage of single-voxel spectroscopy, efficient encoding schemes using spiral k-space trajectories have been successfully deployed, enabling acquisition of volumetric CSI in <5 min. We assessed feasibility of using 3-D spiral CSI sequence routinely in pediatric clinical settings by comparing its reconstructed spectra against SVS spectra. Volumetric spiral CSI obtained spectra from 2-cc isotropic voxels over a 16×16×10-cm region. SVS acquisition encoded a 3.4-cc (1.5-mm) isotropic voxel. Acquisition time was 3 min for every technique. Data were gathered prospectively from 11 random pediatric patients. Spectra from left basal ganglia were obtained using both techniques and were processed with post-processing software. The following metabolite ratios were calculated: N-acetylaspartate/creatine (NAA/Cr), choline/creatine (Cho/Cr), lactate/creatine (Lac/Cr) and N-acetylapartate/choline (NAA/Cho). We collected data on 11 children ages 4 days to 10 years. In 10/11 cases, spectral quality of both methods was acceptable. Considering 10/11 cases, we found a statistically significant difference between SVS and 3-D spiral CSI for all three ratios. However, this difference was fixed and was probably caused by a fixed bias. This means that 3-D spiral CSI can be used instead of SVS by removing the mean difference between the methods for each ratio. Accelerated 3-D CSI is feasible in pediatric patients and can potentially substitute for SVS.

Focus on Resiliency: A Process-Oriented Approach to Security

DTIC Science & Technology

2005-11-01

by ANSI Std Z39-18 © 2005 Carnegie Mellon University CSI v1.0 2 Agenda About the SEI Characterizing the problem Security, resiliency, and risk A...2005 Carnegie Mellon University CSI v1.0 5 SEI Technical Programs Product Line Systems Dynamic Systems Software Engineering Process Management...University CSI v1.0 7 What is the problem? Is your organization’s security capability sufficient to identify and manage risks that result from failed

Frequency- and doping-level influence on electric and dielectric properties of PolySi/SiO2/cSi (MOS) structures

NASA Astrophysics Data System (ADS)

Doukhane, N.; Birouk, B.

2018-03-01

The electric and dielectric characteristics of PolySi/SiO2/cSi (MOS) structure, such as series resistance ( R s), dielectric constants ( ɛ') and ( ɛ″), dielectric losses (tan δ), and the ac electric conductivity ( σ ac), were studied in the frequency range 100 kHz-1 MHz for various doping levels and two thicknesses for the polysilicon layer (100 and 175 nm). The experimental results show that the C and G/ ω characteristics are very sensitive to the frequency due to the presence of interface states. Series resistance R s is deduced from C and G/ ω measurements and is plotted as a function of the frequency for various doping levels. It is found to decrease with frequency and doping level. To determine {ɛ ^' }, ɛ″, tan δ, and {σ _{{ac}}}, the admittance technique was used. An interesting behavior of the constants, {ɛ ^' } and ɛ″, was noticed. The {ɛ ^' } values fit led to relations between {ɛ ^' } and the frequency, on one hand, and between {ɛ ^' } and the electric conductivity of the polysilicon layers on the other. These relations make it possible to interpolate directly between two experimental points for a given frequency. The analysis of the results shows that the values of {ɛ ^' }, ɛ″, and tan δ decrease with increasing frequency. This is due to the fact that in the region of low frequencies, interfacial polarization occurs easily, and the interface states between Si and SiO2 contribute to the improvement of the dielectric properties of the PolySi/SiO2/cSi structures. The study also emphasizes that the ac electric conductivity increases with the increase in frequency and doping level; this causes to the reduction in series resistance.

Effects of premature stimulation on HERG K+ channels

PubMed Central

Lu, Yu; Mahaut-Smith, Martyn P; Varghese, Anthony; Huang, Christopher L-H; Kemp, Paul R; Vandenberg, Jamie I

2001-01-01

The unusual kinetics of human ether-à-go-go-related gene (HERG) K+ channels are consistent with a role in the suppression of arrhythmias initiated by premature beats. Action potential clamp protocols were used to investigate the effect of premature stimulation on HERG K+ channels, transfected in Chinese hamster ovary cells, at 37 °C. HERG K+ channel currents peaked during the terminal repolarization phase of normally paced action potential waveforms. However, the magnitude of the current and the time point at which conductance was maximal depended on the type of action potential waveform used (epicardial, endocardial, Purkinje fibre or atrial). HERG K+ channel currents recorded during premature action potentials consisted of an early transient outward current followed by a sustained outward current. The magnitude of the transient current component showed a biphasic dependence on the coupling interval between the normally paced and premature action potentials and was maximal at a coupling interval equivalent to 90% repolarization (APD90) for ventricular action potentials. The largest transient current response occurred at shorter coupling intervals for Purkinje fibre (APD90– 20 ms) and atrial (APD90– 30 ms) action potentials. The magnitude of the sustained current response following premature stimulation was similar to that recorded during the first action potential for ventricular action potential waveforms. However, for Purkinje and atrial action potentials the sustained current response was significantly larger during the premature action potential than during the normally paced action potential. A Markov model that included three closed states, one open and one inactivated state with transitions permitted between the pre-open closed state and the inactivated state, successfully reproduced our results for the effects of premature stimuli, both during square pulse and action potential clamp waveforms. These properties of HERG K+ channels may help to suppress arrhythmias initiated by early afterdepolarizations and premature beats in the ventricles, Purkinje fibres or atria. PMID:11744759

Serum Procalcitonin for Predicting Significant Infections and Mortality in Pediatric Oncology.

PubMed

Gunasekaran, Vinod; Radhakrishnan, Nita; Dinand, Veronique; Sachdeva, Anupam

2016-12-15

To evaluate the role of serum procalcitonin (PCT) level at admission in predicting significant infections and deaths among children on chemotherapy presenting with fever. Children with clinically significant (CSI) and microbiologically documented (MDI) infections were identified using standard definitions. Association of PCT with CSI, MDI and mortality was analyzed. We evaluated 821 febrile episodes in 316 children. CSI, MDI and deaths were seen in 40.9%, 20.1% and 2.9%, respectively. PCT levels ranged from 0.05-560ng/mL. Median PCT was higher in episodes with CSI (0.80 vs. 0.28) and MDI (0.71 vs. 0.34) (P<0.001). PCT ≥0.7ng/mL optimally predicted CSI (AUC-0.740) and MDI (AUC-0.636). Relative risk of mortality for PCT ≥5ng/mL was 7.1. PCT ≥0.7ng/mL had poor sensitivity (45-55%) but good specificity and NPV (70-90%). PCT was elevated in nearly half of documented viral and fungal infections. PCT predicts significant infections and mortality in pediatric oncology but it has poor sensitivity to guide clinical decisions.

Biosorption of Cd(II) and Cs(I) from aqueous solution by live and dead cells of Saccharomyces carlsbergensis PTCC 5051.

PubMed

Sayyadi, Shayan; Ahmady-Asbchin, Salman; Kamali, Kasra

2018-02-01

The biosorption characteristics of Cd(II) and Cs(I) using live and dead cells of Saccharomyces carlsbergensis PTCC 5051 as biosorbents have been investigated in the present research. The influence of different experimental parameters such as initial pH (pHi), shaking rate, sorption time and initial metal concentration was evaluated. The optimum pH was obtained as 4 for Cd(II) and 7 for Cs(I). The experimental adsorption data were fitted to the Langmuir linear equation adsorption model. The highest metal uptake values of 0.593 and 0.473 mmol g -1 were calculated for Cd(II) and Cs(I), respectively. The results of Fourier transform infrared analysis suggested the involvement of amine, carboxyl and hydroxyl groups during the biosorption process and also indicated that more functional groups were involved in the biosorption process of live adsorbents, compared with those linked to dead biomass. The results showed that the biomass of S. carlsbergensis PTCC 5051 is a suitable biosorbent for the removal of Cd(II) and Cs(I) from the aqueous solutions.

Inactivation of Campylobacter jejuni by chlorine and monochloramine.

PubMed Central

Blaser, M J; Smith, P F; Wang, W L; Hoff, J C

1986-01-01

Campylobacter jejuni and closely related organisms are important bacterial causes of acute diarrheal illness in the United States. Both endemic and epidemic infections have been associated with consuming untreated or improperly treated surface water. We compared susceptibility of three C. jejuni strains and Escherichia coli ATCC 11229 with standard procedures used to disinfect water. Inactivation of bacterial preparations with 0.1 mg of chlorine and 1.0 mg of monochloramine per liter was determined at pH 6 and 8 and at 4 and 25 degrees C. Under virtually every condition tested, each of the three C. jejuni strains was more susceptible than the E. coli control strain, with greater than 99% inactivation after 15 min of contact with 1.0 mg of monochloramine per liter or 5 min of contact with 0.1 mg of free chlorine per liter. Results of experiments in which an antibiotic-containing medium was used suggest that a high proportion of the remaining cells were injured. An animal-passaged C. jejuni strain was as susceptible to chlorine disinfection as were laboratory-passaged strains. These results suggest that disinfection procedures commonly used for treatment of drinking water to remove coliform bacteria are adequate to eliminate C. jejuni and further correlate with the absence of outbreaks associated with properly treated water. PMID:3954344

Inhibitory Effects of Honokiol on the Voltage-Gated Potassium Channels in Freshly Isolated Mouse Dorsal Root Ganglion Neurons.

PubMed

Sheng, Anqi; Zhang, Yan; Li, Guang; Zhang, Guangqin

2018-02-01

Voltage-gated potassium (K V ) currents, subdivided into rapidly inactivating A-type currents (I A ) and slowly inactivating delayed rectifier currents (I K ), play a fundamental role in modulating pain by controlling neuronal excitability. The effects of Honokiol (Hon), a natural biphenolic compound derived from Magnolia officinalis, on K V currents were investigated in freshly isolated mouse dorsal root ganglion neurons using the whole-cell patch clamp technique. Results showed that Hon inhibited I A and I K in concentration-dependent manner. The IC 50 values for block of I A and I K were 30.5 and 25.7 µM, respectively. Hon (30 µM) shifted the steady-state activation curves of I A and I K to positive potentials by 17.6 and 16.7 mV, whereas inactivation and recovery from the inactivated state of I A were unaffected. These results suggest that Hon preferentially interacts with the active states of the I A and I K channels, and has no effect on the resting state and inactivated state of the I A channel. Blockade on K + channels by Hon may contribute to its antinociceptive effect, especially anti-inflammatory pain.

Quality Assurance on Undoped CsI Crystals for the Mu2e Experiment

NASA Astrophysics Data System (ADS)

Atanov, N.; Baranov, V.; Budagov, J.; Davydov, Yu. I.; Glagolev, V.; Tereshchenko, V.; Usubov, Z.; Cervelli, F.; Di Falco, S.; Donati, S.; Morescalchi, L.; Pedreschi, E.; Pezzullo, G.; Raffaelli, F.; Spinella, F.; Colao, F.; Cordelli, M.; Corradi, G.; Diociaiuti, E.; Donghia, R.; Giovannella, S.; Happacher, F.; Martini, M.; Miscetti, S.; Ricci, M.; Saputi, A.; Sarra, I.; Echenard, B.; Hitlin, D. G.; Hu, C.; Miyashita, T.; Porter, F.; Zhang, L.; Zhu, R.-Y.; Grancagnolo, F.; Tassielli, G.; Murat, P.

2018-02-01

The Mu2e experiment is constructing a calorimeter consisting of 1,348 undoped CsI crystals in two disks. Each crystal has a dimension of 34 x 34 x 200 mm, and is readout by a large area silicon PMT array. A series of technical specifications was defined according to physics requirements. Preproduction CsI crystals were procured from three firms: Amcrys, Saint-Gobain and Shanghai Institute of Ceramics. We report the quality assurance on crystal's scintillation properties and their radiation hardness against ionization dose and neutrons. With a fast decay time of 30 ns and a light output of more than 100 p.e./MeV measured with a bi-alkali PMT, undoped CsI crystals provide a cost-effective solution for the Mu2e experiment.

Conjugated Polymers/DNA Hybrid Materials for Protein Inactivation.

PubMed

Zhao, Likun; Zhang, Jiangyan; Xu, Huiming; Geng, Hao; Cheng, Yongqiang

2016-09-07

Chromophore-assisted light inactivation (CALI) is a powerful tool for analyzing protein functions due to the high degree of spatial and temporal resolution. In this work, we demonstrate a CALI approach based on conjugated polymers (CPs)/DNA hybrid material for protein inactivation. The target protein is conjugated with single-stranded DNA in advance. Single-stranded DNA can form CPs/DNA hybrid material with cationic CPs via electrostatic and hydrophobic interactions. Through the formation of CPs/DNA hybrid material, the target protein that is conjugated with DNA is brought into close proximity to CPs. Under irradiation, CPs harvest light and generate reactive oxygen species (ROS), resulting in the inactivation of the adjacent target protein. This approach can efficiently inactivate any target protein which is conjugated with DNA and has good specificity and universality, providing a new strategy for studies of protein function and adjustment of protein activity.

Role of Global Alliance for Vaccines and Immunization (GAVI) in Accelerating Inactivated Polio Vaccine Introduction.

PubMed

Thacker, Naveen; Thacker, Deep; Pathak, Ashish

2016-08-07

Global Alliance for Vaccines and Immunization (GAVI, the Vaccine Alliance) is an international organization built through public-private partnership. GAVI has supported more than 200 vaccine introductions in the last 5 years by financing major proportion of costs of vaccine to 73 low-income countries using a co-financing model. GAVI has worked in close co-ordination with Global Polio Eradication Initiative (GPEI) since 2013, to strengthen health systems in countries so as to accelerate introduction of inactivated polio vaccine (IPV). GAVI is involved in many IPV related issues like demand generation, supply, market shaping, communications, country readiness etc. Most of the 73 GAVI eligible countries are also high priority countries for GPEI. GAVI support has helped India to accelerate introduction of IPV in all its states. However, GAVI faces challenges in IPV supply-related issues in the near future. It also needs to play a key role in global polio legacy planning and implementation.

Mixed-Timescale Per-Group Hybrid Precoding for Multiuser Massive MIMO Systems

NASA Astrophysics Data System (ADS)

Teng, Yinglei; Wei, Min; Liu, An; Lau, Vincent; Zhang, Yong

2018-05-01

Considering the expensive radio frequency (RF) chain, huge training overhead and feedback burden issues in massive MIMO, in this letter, we propose a mixed-timescale per-group hybrid precoding (MPHP) scheme under an adaptive partially-connected RF precoding structure (PRPS), where the RF precoder is implemented using an adaptive connection network (ACN) and M analog phase shifters (APSs), where M is the number of antennas at the base station (BS). Exploiting the mixed-time stage channel state information (CSI) structure, the joint-design of ACN and APSs is formulated as a statistical signal-to-leakage-and-noise ratio (SSLNR) maximization problem, and a heuristic group RF precoding (GRFP) algorithm is proposed to provide a near-optimal solution. Simulation results show that the proposed design advances at better energy efficiency (EE) and lower hardware cost, CSI signaling overhead and computational complexity than the conventional hybrid precoding (HP) schemes.

Controls structures interaction, an interdisciplinary challenge for large spacecraft

NASA Technical Reports Server (NTRS)

Hanks, Brantley R.

1990-01-01

Controls structures interaction (CSI), a phenomenon which occurs when control forces interact with the flexible motion of a structure, can, if improperly treated in design and development, cause reduced performance or control instabilities. Properly applied, it can improve flexible spacecraft performance. In this paper, the NASA CSI technology program for future spacecraft applications is described. The program objectives and organization are outlined, and the nature of individual program tasks is described. The interdisciplinary aspects of CSI are also addressed.

Design data brochure for CSI series V solar heating system

NASA Technical Reports Server (NTRS)

1978-01-01

Generalized information on system configuration, system sizing, and mechanical layout is presented to assist the architect or designer in preparing construction drawings and specifications for the installation of the CSI integrated solar heating systems. Efficiency in space utilization of a full length collector and the importance of proper sizing of the collector array are among the topics discussed. Details of storage and transport subsystems are provided along with drawings and specifications of all components of the CSI system.

Charter Schools Indicators: A Report from the Center on Educational Governance University of Southern California. CSI-USC 2007

ERIC Educational Resources Information Center

Center on Educational Governance, 2007

2007-01-01

Like other public schools, California charter schools are judged primarily by one measure: student test scores. Though necessary, the Academic Performance Index and Average Yearly Progress scores can't assess charter schools' broad dimensions of student learning, program effectiveness and school operations. The state's accountability system…

A Comprehensive evaluation of groundwater vulnerability to saltwater up-coning and sea water intrusion in a coastal aquifer (case study: Ghaemshahr-juybar aquifer)

NASA Astrophysics Data System (ADS)

Motevalli, Alireza; Moradi, Hamid Reza; Javadi, Saman

2018-02-01

Aquifer salinization has recently increased significantly due to human activity and has caused irreparable environmental and economic effects. In this research, a new method is proposed for modeling the vulnerability to salinity for the Ghaemshahr-juybar aquifer. Specifically, the GALDIT (Sea water intrusion) and TAWLBIC (Saltwater up-coning) indices were combined to produce a map of vulnerability (Comprehensive Salinity Index or CSI) to seawater intrusion of a region near the coast and saltwater up-coning away from the coast, respectively. Single parameter and removal layer sensitivity analysis were performed in order to identify the sensitive parameters and achieve optimal weights (through the single-parameter method) of contributing factors in all three methods. The three optimized methods produced were GALDIT-Opt, TAWLBIC-Opt and CSI-Opt. To assess the accuracy of the original maps and optimal ones, the Pearson correlation was used. Results indicated that the Pearson correlation of the optimized GALDIT, TAWLBIC and CSI model was better than GALDIT, TAWLBIC and CSI. The results show that the increase in correlation between EC (Electrical Conductivity), TDS (Total Dissolved Solids) and SAR (Sodium Adsorption Ratio) from the GALDIT model to the CSI-Opt model from values of 0.64, 0.56 and 0.68 has improved to values of 0.81, 0.88 and 0.91, respectively. The highest concentration of EC, with a value of 7050 μs/cm, is sampled in the areas of the east and northwest of the Ghaemshahr-juybar aquifer, which are classified in the CSI-Opt model as high and very high vulnerability levels. The highest concentration of TDS and SAR has been found in the east, northwest and northeast of the Ghaemshahr-juybar aquifer with a value of 4724 ppm for TDS and 14 mg/l for SAR that have been modeled in the CSI-Opt index as highly vulnerable areas. Eventually, CSI mapping can be used as an efficient tool in prioritizing in terms of the vulnerability to aquifer salinity, carrying out adjustments, recharge, and adaptation policies for this issue.

Single-user MIMO versus multi-user MIMO in distributed antenna systems with limited feedback

NASA Astrophysics Data System (ADS)

Schwarz, Stefan; Heath, Robert W.; Rupp, Markus

2013-12-01

This article investigates the performance of cellular networks employing distributed antennas in addition to the central antennas of the base station. Distributed antennas are likely to be implemented using remote radio units, which is enabled by a low latency and high bandwidth dedicated link to the base station. This facilitates coherent transmission from potentially all available antennas at the same time. Such distributed antenna system (DAS) is an effective way to deal with path loss and large-scale fading in cellular systems. DAS can apply precoding across multiple transmission points to implement single-user MIMO (SU-MIMO) and multi-user MIMO (MU-MIMO) transmission. The throughput performance of various SU-MIMO and MU-MIMO transmission strategies is investigated in this article, employing a Long-Term evolution (LTE) standard compliant simulation framework. The previously theoretically established cell-capacity improvement of MU-MIMO in comparison to SU-MIMO in DASs is confirmed under the practical constraints imposed by the LTE standard, even under the assumption of imperfect channel state information (CSI) at the base station. Because practical systems will use quantized feedback, the performance of different CSI feedback algorithms for DASs is investigated. It is shown that significant gains in the CSI quantization accuracy and in the throughput of especially MU-MIMO systems can be achieved with relatively simple quantization codebook constructions that exploit the available temporal correlation and channel gain differences.

Atomic Structure of Interface States in Silicon Heterojunction Solar Cells

NASA Astrophysics Data System (ADS)

George, B. M.; Behrends, J.; Schnegg, A.; Schulze, T. F.; Fehr, M.; Korte, L.; Rech, B.; Lips, K.; Rohrmüller, M.; Rauls, E.; Schmidt, W. G.; Gerstmann, U.

2013-03-01

Combining orientation dependent electrically detected magnetic resonance and g tensor calculations based on density functional theory we assign microscopic structures to paramagnetic states involved in spin-dependent recombination at the interface of hydrogenated amorphous silicon crystalline silicon (a-Si:H/c-Si) heterojunction solar cells. We find that (i) the interface exhibits microscopic roughness, (ii) the electronic structure of the interface defects is mainly determined by c-Si, (iii) we identify the microscopic origin of the conduction band tail state in the a-Si:H layer, and (iv) present a detailed recombination mechanism.

Conformational Transition Pathway in the Activation Process of Allosteric Glucokinase

PubMed Central

Shi, Ting; Zhao, Yaxue; Chen, Yingyi; Li, Xiaobai; Liu, Xinyi; Huang, Zhimin; Zhang, Jian

2013-01-01

Glucokinase (GK) is a glycolytic enzyme that plays an important role in regulating blood glucose level, thus acting as a potentially attractive target for drug discovery in the treatment of diabetes of the young type 2 and persistent hyperinsulinemic hypoglycemia of infancy. To characterize the activation mechanism of GK from the super-open state (inactive state) to the closed state (active state), a series of conventional molecular dynamics (MD) and targeted MD (TMD) simulations were performed on this enzyme. Conventional MD simulation showed a specific conformational ensemble of GK when the enzyme is inactive. Seven TMD simulations depicted a reliably conformational transition pathway of GK from the inactive state to the active state, and the components important to the conformational change of GK were identified by analyzing the detailed structures of the TMD trajectories. In combination with the inactivation process, our findings showed that the whole conformational pathway for the activation-inactivation-activation of GK is a one-direction circulation, and the active state is less stable than the inactive state in the circulation. Additionally, glucose was demonstrated to gradually modulate its binding pose with the help of residues in the large domain and connecting region of GK during the activation process. Furthermore, the obtained energy barriers were used to explain the preexisting equilibrium and the slow binding kinetic process of the substrate by GK. The simulated results are in accordance with the recent findings from the mutagenesis experiments and kinetic analyses. Our observations reveal a complicated conformational process in the allosteric protein, resulting in new knowledge about the delicate mechanisms for allosteric biological macromolecules that will be useful in drug design for targeting allosteric proteins. PMID:23409066

CsI Calorimeter for a Compton-Pair Telescope

NASA Astrophysics Data System (ADS)

Grove, Eric J.

We propose to build and test a hodoscopic CsI(Tl) scintillating-crystal calorimeter for a medium-energy γ-ray Compton and pair telescope. The design and technical approach for this calorimeter relies deeply on heritage from the Fermi LAT CsI Calorimeter, but it dramatically improves the low-energy performance of that design by reading out the scintillation light with silicon photomultipliers (SiPMs), making the technology developed for Fermi applicable in the Compton regime. While such a hodoscopic calorimeter is useful for an entire class of medium-energy γ-ray telescope designs, we propose to build it explicitly to support beam tests and balloon flight of the Proto-ComPair telescope, the development and construction of which was funded in a four-year APRA program beginning in 2015 ("ComPair: Steps to a Medium Energy γ-ray Mission" with PI J. McEnery of GSFC). That award did not include funding for its CsI calorimeter subsystem, and this proposal is intended to cover that gap. ComPair is a MIDEX-class instrument concept to perform a high-sensitivity survey of the γ-ray sky from 0.5 MeV to 500 MeV. ComPair is designed to provide a dramatic increase in sensitivity relative to previous instruments in this energy range (predominantly INTEGRAL/SPI and Compton COMPTEL), with the same transformative sensitivity increase - and corresponding scientific return- that the Fermi Large Area Telescope provided relative to Compton EGRET. To enable transformative science over a broad range of MeV energies and with a wide field of view, ComPair is a combined Compton telescope and pair telescope employing a silicon-strip tracker (for Compton scattering and pair conversion and tracking) and a solid-state CdZnTe calorimeter (for Compton absorption) and CsI calorimeter (for pair calorimetry), surrounded by a plastic scintillator anti-coincidence detector. Under the current proposal, we will complete the detailed design, assembly, and test of the CsI calorimeter for the risk-reduction prototype telescope, Proto-ComPair. We will: 1. Purchase CsI(Tl) crystals, Silicon Photomultipliers (SiPMs), and components for the analog and digital readout of the SiPMs; 2. Assemble and test Crystal Detector Elements (CDEs) from crystals, SiPMs and optical wrap; 3. Assemble and test analog and digital front-end and readout control boards; 4. Fabricate the mechanical structure that supports and contains the CDEs and electronics boards; and 5. Assemble and test the CsI calorimeter, and integrate it with the remainder of the Proto-ComPair subsystems. The PI team for this proposal conceived, designed, developed, assembled, tested, and currently operates the LAT calorimeter and is uniquely qualified to leverage the experience gained from that effort for ComPair.

Quality Assurance on Undoped CsI Crystals for the Mu2e Experiment

DOE PAGES

Atanov, N.; Baranov, V.; Budagov, J.; ...

2017-12-21

The Mu2e experiment is constructing a calorimeter consisting of 1,348 undoped CsI crystals in two disks. Each crystal has a dimension of 34 x 34 x 200 mm 3, and is readout by a large area silicon PMT array. A series of technical specifications was defined according to physics requirements. Preproduction CsI crystals were procured from three firms: Amcrys, Saint-Gobain and Shanghai Institute of Ceramics. We report the quality assurance on crystal's scintillation properties and their radiation hardness against ionization dose and neutrons. With a fast decay time of 30 ns and a light output of more than 100 p.e./MeVmore » measured with a bi-alkali PMT, undoped CsI crystals provide a cost-effective solution for the Mu2e experiment.« less

Quality Assurance on Undoped CsI Crystals for the Mu2e Experiment

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

Atanov, N.; Baranov, V.; Budagov, J.

The Mu2e experiment is constructing a calorimeter consisting of 1,348 undoped CsI crystals in two disks. Each crystal has a dimension of 34 x 34 x 200 mm 3, and is readout by a large area silicon PMT array. A series of technical specifications was defined according to physics requirements. Preproduction CsI crystals were procured from three firms: Amcrys, Saint-Gobain and Shanghai Institute of Ceramics. We report the quality assurance on crystal's scintillation properties and their radiation hardness against ionization dose and neutrons. With a fast decay time of 30 ns and a light output of more than 100 p.e./MeVmore » measured with a bi-alkali PMT, undoped CsI crystals provide a cost-effective solution for the Mu2e experiment.« less

Hail detection algorithm for the Global Precipitation Measuring mission core satellite sensors

NASA Astrophysics Data System (ADS)

Mroz, Kamil; Battaglia, Alessandro; Lang, Timothy J.; Tanelli, Simone; Cecil, Daniel J.; Tridon, Frederic

2017-04-01

By exploiting an abundant number of extreme storms observed simultaneously by the Global Precipitation Measurement (GPM) mission core satellite's suite of sensors and by the ground-based S-band Next-Generation Radar (NEXRAD) network over continental US, proxies for the identification of hail are developed based on the GPM core satellite observables. The full capabilities of the GPM observatory are tested by analyzing more than twenty observables and adopting the hydrometeor classification based on ground-based polarimetric measurements as truth. The proxies have been tested using the Critical Success Index (CSI) as a verification measure. The hail detection algorithm based on the mean Ku reflectivity in the mixed-phase layer performs the best, out of all considered proxies (CSI of 45%). Outside the Dual frequency Precipitation Radar (DPR) swath, the Polarization Corrected Temperature at 18.7 GHz shows the greatest potential for hail detection among all GMI channels (CSI of 26% at a threshold value of 261 K). When dual variable proxies are considered, the combination involving the mixed-phase reflectivity values at both Ku and Ka-bands outperforms all the other proxies, with a CSI of 49%. The best-performing radar-radiometer algorithm is based on the mixed-phase reflectivity at Ku-band and on the brightness temperature (TB) at 10.7 GHz (CSI of 46%). When only radiometric data are available, the algorithm based on the TBs at 36.6 and 166 GHz is the most efficient, with a CSI of 27.5%.

Cat-doping: Novel method for phosphorus and boron shallow doping in crystalline silicon at 80 °C

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

Matsumura, Hideki; Hayakawa, Taro; Ohta, Tatsunori

Phosphorus (P) or boron (B) atoms can be doped at temperatures as low as 80 to 350 °C, when crystalline silicon (c-Si) is exposed only for a few minutes to species generated by catalytic cracking reaction of phosphine (PH₃) or diborane (B₂H₆) with heated tungsten (W) catalyzer. This paper is to investigate systematically this novel doping method, “Cat-doping”, in detail. The electrical properties of P or B doped layers are studied by the Van der Pauw method based on the Hall effects measurement. The profiles of P or B atoms in c-Si are observed by secondary ion mass spectrometry mainlymore » from back side of samples to eliminate knock-on effects. It is confirmed that the surface of p-type c-Si is converted to n-type by P Cat-doping at 80 °C, and similarly, that of n-type c-Si is to p-type by B Cat-doping. The doping depth is as shallow as 5 nm or less and the electrically activated doping concentration is 10¹⁸ to 10¹⁹cm⁻³ for both P and B doping. It is also found that the surface potential of c-Si is controlled by the shallow Cat-doping and that the surface recombination velocity of minority carriers in c-Si can be enormously lowered by this potential control.« less

Comparison of risk of radiogenic second cancer following photon and proton craniospinal irradiation for a pediatric medulloblastoma patient

NASA Astrophysics Data System (ADS)

Zhang, Rui; Howell, Rebecca M.; Giebeler, Annelise; Taddei, Phillip J.; Mahajan, Anita; Newhauser, Wayne D.

2013-02-01

Pediatric patients who received radiation therapy are at risk of developing side effects such as radiogenic second cancer. We compared proton and photon therapies in terms of the predicted risk of second cancers for a 4 year old medulloblastoma patient receiving craniospinal irradiation (CSI). Two CSI treatment plans with 23.4 Gy or Gy (RBE) prescribed dose were computed: a three-field 6 MV photon therapy plan and a four-field proton therapy plan. The primary doses for both plans were determined using a commercial treatment planning system. Stray radiation doses for proton therapy were determined from Monte Carlo simulations, and stray radiation doses for photon therapy were determined from measured data. Dose-risk models based on the Biological Effects of Ionization Radiation VII report were used to estimate the risk of second cancer in eight tissues/organs. Baseline predictions of the relative risk for each organ were always less for proton CSI than for photon CSI at all attained ages. The total lifetime attributable risk of the incidence of second cancer considered after proton CSI was much lower than that after photon CSI, and the ratio of lifetime risk was 0.18. Uncertainty analysis revealed that the qualitative findings of this study were insensitive to any plausible changes of dose-risk models and mean radiation weighting factor for neutrons. Proton therapy confers lower predicted risk of second cancer than photon therapy for the pediatric medulloblastoma patient.

Inter-subunit interactions across the upper voltage sensing-pore domain interface contribute to the concerted pore opening transition of Kv channels.

PubMed

Shem-Ad, Tzilhav; Irit, Orr; Yifrach, Ofer

2013-01-01

The tight electro-mechanical coupling between the voltage-sensing and pore domains of Kv channels lies at the heart of their fundamental roles in electrical signaling. Structural data have identified two voltage sensor pore inter-domain interaction surfaces, thus providing a framework to explain the molecular basis for the tight coupling of these domains. While the contribution of the intra-subunit lower domain interface to the electro-mechanical coupling that underlies channel opening is relatively well understood, the contribution of the inter-subunit upper interface to channel gating is not yet clear. Relying on energy perturbation and thermodynamic coupling analyses of tandem-dimeric Shaker Kv channels, we show that mutation of upper interface residues from both sides of the voltage sensor-pore domain interface stabilizes the closed channel state. These mutations, however, do not affect slow inactivation gating. We, moreover, find that upper interface residues form a network of state-dependent interactions that stabilize the open channel state. Finally, we note that the observed residue interaction network does not change during slow inactivation gating. The upper voltage sensing-pore interaction surface thus only undergoes conformational rearrangements during channel activation gating. We suggest that inter-subunit interactions across the upper domain interface mediate allosteric communication between channel subunits that contributes to the concerted nature of the late pore opening transition of Kv channels.

A Conserved Acidic Motif in the N-Terminal Domain of Nitrate Reductase Is Necessary for the Inactivation of the Enzyme in the Dark by Phosphorylation and 14-3-3 Binding1

PubMed Central

Pigaglio, Emmanuelle; Durand, Nathalie; Meyer, Christian

1999-01-01

It has previously been shown that the N-terminal domain of tobacco (Nicotiana tabacum) nitrate reductase (NR) is involved in the inactivation of the enzyme by phosphorylation, which occurs in the dark (L. Nussaume, M. Vincentz, C. Meyer, J.P. Boutin, and M. Caboche [1995] Plant Cell 7: 611–621). The activity of a mutant NR protein lacking this N-terminal domain was no longer regulated by light-dark transitions. In this study smaller deletions were performed in the N-terminal domain of tobacco NR that removed protein motifs conserved among higher plant NRs. The resulting truncated NR-coding sequences were then fused to the cauliflower mosaic virus 35S RNA promoter and introduced in NR-deficient mutants of the closely related species Nicotiana plumbaginifolia. We found that the deletion of a conserved stretch of acidic residues led to an active NR protein that was more thermosensitive than the wild-type enzyme, but it was relatively insensitive to the inactivation by phosphorylation in the dark. Therefore, the removal of this acidic stretch seems to have the same effects on NR activation state as the deletion of the N-terminal domain. A hypothetical explanation for these observations is that a specific factor that impedes inactivation remains bound to the truncated enzyme. A synthetic peptide derived from this acidic protein motif was also found to be a good substrate for casein kinase II. PMID:9880364

DMD-based implementation of patterned optical filter arrays for compressive spectral imaging.

PubMed

Rueda, Hoover; Arguello, Henry; Arce, Gonzalo R

2015-01-01

Compressive spectral imaging (CSI) captures multispectral imagery using fewer measurements than those required by traditional Shannon-Nyquist theory-based sensing procedures. CSI systems acquire coded and dispersed random projections of the scene rather than direct measurements of the voxels. To date, the coding procedure in CSI has been realized through the use of block-unblock coded apertures (CAs), commonly implemented as chrome-on-quartz photomasks. These apertures block or permit us to pass the entire spectrum from the scene at given spatial locations, thus modulating the spatial characteristics of the scene. This paper extends the framework of CSI by replacing the traditional block-unblock photomasks by patterned optical filter arrays, referred to as colored coded apertures (CCAs). These, in turn, allow the source to be modulated not only spatially but spectrally as well, entailing more powerful coding strategies. The proposed CCAs are synthesized through linear combinations of low-pass, high-pass, and bandpass filters, paired with binary pattern ensembles realized by a digital micromirror device. The optical forward model of the proposed CSI architecture is presented along with a proof-of-concept implementation, which achieves noticeable improvements in the quality of the reconstruction.

Comparative cognitive effects of bilateral subthalamic stimulation and subcutaneous continuous infusion of apomorphine in Parkinson's disease.

PubMed

Alegret, Montse; Valldeoriola, Francesc; Martí, MaJosé; Pilleri, Manuela; Junqué, Carme; Rumià, Jordi; Tolosa, Eduardo

2004-12-01

Bilateral subthalamic deep brain stimulation (STN-DBS) and continuous subcutaneous infusion of apomorphine (APM-csi) can provide a comparable improvement on motor function in patients with advanced Parkinson's disease (PD), but the mechanisms by which both therapies exert their effects are different. We analyzed the cognitive effects of APM-csi. We also compared neuropsychological effects induced by STN-DBS and APM-csi in advanced PD to ascertain the neuropsychological aspects relevant in determining the therapeutic procedure that is the most appropriate in a particular patient. We studied 9 patients treated with STN-DBS and 7 patients with APM-csi. Neuropsychological measures included Rey's Auditory-Verbal Learning, Stroop, Trail Making, phonetic verbal fluency, and Judgment of Line Orientation tests. In the APM-csi group, significant changes were not observed in the neuropsychological tests performance. By contrast, in the STN-DBS group, moderate worsening was found in phonetic verbal fluency and Stroop Naming scores that was partially reversible at long-term follow-up and did not have consequences on regular activities. Consequently, these findings could be interpreted as being not relevant in deciding the most suitable treatment in a given patient. 2004 Movement Disorder Society.

American Association of Critical-Care Nurses

MedlinePlus

... Influencing Sleep in the ICU Explore Explore New Nurses Experienced Nurses Educators/Managers Advanced Practice Membership As a new ... More CSI Academy AACN CSI Academy develops staff nurses as leaders and change agents who drive improved ...

Structures of closed and open states of a voltage-gated sodium channel

PubMed Central

Lenaeus, Michael J.; Gamal El-Din, Tamer M.; Ramanadane, Karthik; Pomès, Régis; Zheng, Ning; Catterall, William A.

2017-01-01

Bacterial voltage-gated sodium channels (BacNavs) serve as models of their vertebrate counterparts. BacNavs contain conserved voltage-sensing and pore-forming domains, but they are homotetramers of four identical subunits, rather than pseudotetramers of four homologous domains. Here, we present structures of two NaVAb mutants that capture tightly closed and open states at a resolution of 2.8–3.2 Å. Introduction of two humanizing mutations in the S6 segment (NaVAb/FY: T206F and V213Y) generates a persistently closed form of the activation gate in which the intracellular ends of the four S6 segments are drawn tightly together to block ion permeation completely. This construct also revealed the complete structure of the four-helix bundle that forms the C-terminal domain. In contrast, truncation of the C-terminal 40 residues in NavAb/1–226 captures the activation gate in an open conformation, revealing the open state of a BacNav with intact voltage sensors. Comparing these structures illustrates the full range of motion of the activation gate, from closed with its orifice fully occluded to open with an orifice of ∼10 Å. Molecular dynamics and free-energy simulations confirm designation of NaVAb/1–226 as an open state that allows permeation of hydrated Na+, and these results also support a hydrophobic gating mechanism for control of ion permeation. These two structures allow completion of a closed–open–inactivated conformational cycle in a single voltage-gated sodium channel and give insight into the structural basis for state-dependent binding of sodium channel-blocking drugs. PMID:28348242

Optimization of the synthesis process of an iron oxide nanocatalyst supported on activated carbon for the inactivation of Ascaris eggs in water using the heterogeneous Fenton-like reaction.

PubMed

Morales-Pérez, Ariadna A; Maravilla, Pablo; Solís-López, Myriam; Schouwenaars, Rafael; Durán-Moreno, Alfonso; Ramírez-Zamora, Rosa-María

2016-01-01

An experimental design methodology was used to optimize the synthesis of an iron-supported nanocatalyst as well as the inactivation process of Ascaris eggs (Ae) using this material. A factor screening design was used for identifying the significant experimental factors for nanocatalyst support (supported %Fe, (w/w), temperature and time of calcination) and for the inactivation process called the heterogeneous Fenton-like reaction (H2O2 dose, mass ratio Fe/H2O2, pH and reaction time). The optimization of the significant factors was carried out using a face-centered central composite design. The optimal operating conditions for both processes were estimated with a statistical model and implemented experimentally with five replicates. The predicted value of the Ae inactivation rate was close to the laboratory results. At the optimal operating conditions of the nanocatalyst production and Ae inactivation process, the Ascaris ova showed genomic damage to the point that no cell reparation was possible showing that this advanced oxidation process was highly efficient for inactivating this pathogen.

Vertebral Body Growth After Craniospinal Irradiation

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

Hartley, Katherine A.; Li Chenghong; Laningham, Fred H.

2008-04-01

Purpose: To estimate the effects of radiotherapy and clinical factors on vertebral growth in patients with medulloblastoma and supratentorial primitive neuroectodermal tumors treated with craniospinal irradiation (CSI) and chemotherapy. Methods and Materials: The height of eight individual or grouped vertebral bodies (C3, C3-C4, T4, T4-T5, C6-T3, T4-T7, L3, L1-L5) was measured before and after CSI (23.4 or 36-39.6 Gy) in 61 patients. Of the 61 patients, 40 were boys and 21 were girls (median age, 7 years; range, 3-13 years), treated between October 1996 and October 2003. Sagittal T{sub 1}-weighted magnetic resonance images were used for the craniocaudal measurements. Themore » measurements numbered 275 (median, 5/patient; range, 3-7). The median follow-up after CSI was 44.1 months (range, 13.8-74.9 months). Results: Significant growth was observed in all measured vertebrae. Excluding C3-C4, the growth rate of the grouped vertebrae was affected by age, gender, and CSI dose (risk classification). The risk classification alone affected the growth rates of C3 (p = 0.002) and L3 (p = 0.02). Before CSI, the length of all vertebral bodies was an increasing function of age (p <0.0001). The C3 length before CSI was affected by gender and risk classification: C3 was longer for female (p = 0.07) and high-risk (p = 0.07) patients. Conclusion: All vertebrae grew significantly after CSI, with the vertebrae of the boys and younger patients growing at a rate greater than that of their counterparts. The effect of age was similar across all vertebrae, and gender had the greatest effect on the growth of the lower cervical and upper thoracic vertebrae. The effect of the risk classification was greatest in the lumbar spine by a factor of {<=}10.« less

The ratio of glycated albumin to hemoglobin A1c measured in IFCC units accurately represents the glycation gap.

PubMed

Akatsuka, Junya; Mochizuki, Mie; Musha, Ikuma; Ohtake, Akira; Kobayashi, Kisho; Kikuchi, Toru; Kikuchi, Nobuyuki; Kawamura, Tomoyuki; Urakami, Tatsuhiko; Sugihara, Shigetaka; Hoshino, Tadao; Amemiya, Shin

2015-01-01

The glycation gap (G-gap: difference between measured hemoglobin A1c [A1C] and the value predicted by its regression on the fructosamine level) is stable and associated with diabetic complications. Measuring A1C level in International Federation of Clinical Chemistry (IFCC) units (A1C-SI; mmol/mol) and National Glycohemoglobin Standardization Program units (A1C-NGSP; %) and using glycated albumin (GA) level instead of fructosamine level for calculating the G-gap, we investigated whether the G-gap is better represented by GA/A1C ratio if expressed in SI units (GA/A1C-SI ratio) rather than in NGSP units (GA/A1C-% ratio). We examined 749 Japanese children with type 1 diabetes using simultaneous GA and A1C measurements. Of these, 369 patients were examined more than five times to assess the consistency of the G-gap and the GA/A1C ratio within individuals. The relationship of GA/A1C-% ratio to the corresponding A1C-NGSP was stronger than that of GA/A1C-SI ratio to A1C-IFCC. At enrollment, the inverse relationship between the GA/A1C-SI ratio and G-gap was highly significant (R(2) = 0.95) compared with that between the GA/A1C-% ratio and G-gap (R(2) = 0.69). A highly significant inverse relationship was also observed between the mean GA/A1C-SI ratio and the mean G-gaps obtained individually over time (R(2) = 0.95) compared with that using the corresponding A1C-NGSP (R(2) = 0.67). We conclude that the G-gap is better represented by the GA/A1C-SI ratio. We propose the use of mean GA/A1C-SI ratios easily obtained individually over time as reference values in Japanese children with type 1 diabetes (6.75 ± 0.60 [means ± SD]).

A multicentre randomised, 1-year comparative effectiveness, parallel-group trial protocol of a physical therapy approach compared to corticosteroid injections

PubMed Central

Deyle, Gail D; Gill, Norman W; Rhon, Daniel I; Allen, Chris S; Allison, Stephen C; Hando, Ben R; Petersen, Evan J; Dusenberry, Douglas I; Bellamy, Nicholas

2016-01-01

Introduction Corticosteroid injections (CSIs) are commonly used as an initial or a primary intervention for knee osteoarthritis (OA). Consistent evidence indicates CSIs offer symptom relief with conflicting reports regarding long-term efficacy. Physical therapy (PT) offers a non-invasive alternative. There is moderate evidence suggesting short-term and long-term symptom relief and functional improvement with PT interventions. Patients with knee OA are more commonly prescribed CSI than PT prior to total joint replacement. UnitedHealthcare and Military Health System data show substantially more total knee replacement patients receive preoperative CSI than PT. There are no studies comparing CSI to a PT approach in individuals with knee OA. The primary objective of this study is to compare the effectiveness of CSI to PT in individuals with knee OA at 1, 2 and 12 months. Methods and analysis We plan to recruit 156 participants meeting established knee OA criteria. Following informed consent, participants will be randomised to receive either CSI or PT. All participants will receive instruction on recommended exercise and weight control strategies plus usual medical care. The CSI intervention consisting of 3 injections and the PT intervention consisting of 8–12 sessions will be spaced over 12 months. Measures of the dependent variables (DVs) will occur at baseline, 4 weeks, 8 weeks, 6 months and 12 months post enrolment. This pragmatic, randomised clinical trial will be a mixed-model 2×5 factorial design. The independent variables are treatment (CSI and PT) and time with five levels from baseline to 1 year. The primary DV is the Western Ontario & McMaster Universities Arthritis Index (WOMAC). We will also compare healthcare utilisation between the 2 groups. Ethics and Dissemination The protocol was approved by the Madigan Army Medical Center Institutional Review Board. The authors intend to publish the results in a peer-reviewed source. Trial Registration Number NCT01427153. PMID:27033961

Downlink Training Techniques for FDD Massive MIMO Systems: Open-Loop and Closed-Loop Training With Memory

NASA Astrophysics Data System (ADS)

Choi, Junil; Love, David J.; Bidigare, Patrick

2014-10-01

The concept of deploying a large number of antennas at the base station, often called massive multiple-input multiple-output (MIMO), has drawn considerable interest because of its potential ability to revolutionize current wireless communication systems. Most literature on massive MIMO systems assumes time division duplexing (TDD), although frequency division duplexing (FDD) dominates current cellular systems. Due to the large number of transmit antennas at the base station, currently standardized approaches would require a large percentage of the precious downlink and uplink resources in FDD massive MIMO be used for training signal transmissions and channel state information (CSI) feedback. To reduce the overhead of the downlink training phase, we propose practical open-loop and closed-loop training frameworks in this paper. We assume the base station and the user share a common set of training signals in advance. In open-loop training, the base station transmits training signals in a round-robin manner, and the user successively estimates the current channel using long-term channel statistics such as temporal and spatial correlations and previous channel estimates. In closed-loop training, the user feeds back the best training signal to be sent in the future based on channel prediction and the previously received training signals. With a small amount of feedback from the user to the base station, closed-loop training offers better performance in the data communication phase, especially when the signal-to-noise ratio is low, the number of transmit antennas is large, or prior channel estimates are not accurate at the beginning of the communication setup, all of which would be mostly beneficial for massive MIMO systems.

Differential state-dependent modification of rat Na{sub v}1.6 sodium channels expressed in human embryonic kidney (HEK293) cells by the pyrethroid insecticides tefluthrin and deltamethrin

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

He, Bingjun; Soderlund, David M., E-mail: dms6@cornell.edu

2011-12-15

We expressed rat Na{sub v}1.6 sodium channels in combination with the rat {beta}1 and {beta}2 auxiliary subunits in human embryonic kidney (HEK293) cells and evaluated the effects of the pyrethroid insecticides tefluthrin and deltamethrin on expressed sodium currents using the whole-cell patch clamp technique. Both pyrethroids produced concentration-dependent, resting modification of Na{sub v}1.6 channels, prolonging the kinetics of channel inactivation and deactivation to produce persistent 'late' currents during depolarization and tail currents following repolarization. Both pyrethroids also produced concentration dependent hyperpolarizing shifts in the voltage dependence of channel activation and steady-state inactivation. Maximal shifts in activation, determined from the voltagemore » dependence of the pyrethroid-induced late and tail currents, were {approx} 25 mV for tefluthrin and {approx} 20 mV for deltamethrin. The highest attainable concentrations of these compounds also caused shifts of {approx} 5-10 mV in the voltage dependence of steady-state inactivation. In addition to their effects on the voltage dependence of inactivation, both compounds caused concentration-dependent increases in the fraction of sodium current that was resistant to inactivation following strong depolarizing prepulses. We assessed the use-dependent effects of tefluthrin and deltamethrin on Na{sub v}1.6 channels by determining the effect of trains of 1 to 100 5-ms depolarizing prepulses at frequencies of 20 or 66.7 Hz on the extent of channel modification. Repetitive depolarization at either frequency increased modification by deltamethrin by {approx} 2.3-fold but had no effect on modification by tefluthrin. Tefluthrin and deltamethrin were equally potent as modifiers of Na{sub v}1.6 channels in HEK293 cells using the conditions producing maximal modification as the basis for comparison. These findings show that the actions of tefluthrin and deltamethrin of Na{sub v}1.6 channels in HEK293 cells differ from the effects of these compounds on Na{sub v}1.6 channels in Xenopus oocytes and more closely reflect the actions of pyrethroids on channels in their native neuronal environment. -- Highlights: Black-Right-Pointing-Pointer We expressed rat Na{sub v}1.6 voltage-gated sodium channels in HEK293 cells. Black-Right-Pointing-Pointer Tefluthrin and deltamethrin caused resting modification of Na{sub v}1.6 channels. Black-Right-Pointing-Pointer Only deltamethrin exhibited use-dependent enhancement of modification. Black-Right-Pointing-Pointer State-dependent effects of pyrethroids are influenced by the cellular context. Black-Right-Pointing-Pointer Channels in HEK293 cells exhibit properties similar to native neuronal channels.« less

[Mechanism of action of neurotoxins acting on the inactivation of voltage-gated sodium channels].

PubMed

Benoit, E

1998-01-01

This review focuses on the mechanism(s) of action of neurotoxins acting on the inactivation of voltage-gated Na channels. Na channels are transmembrane proteins which are fundamental for cellular communication. These proteins form pores in the plasma membrane allowing passive ionic movements to occur. Their opening and closing are controlled by gating systems which depend on both membrane potential and time. Na channels have three functional properties, mainly studied using electrophysiological and biochemical techniques, to ensure their role in the generation and propagation of action potentials: 1) a highly selectivity for Na ions, 2) a rapid opening ("activation"), responsible for the depolarizing phase of the action potential, and 3) a late closing ("inactivation") involved in the repolarizing phase of the action potential. As an essential protein for membrane excitability, the Na channel is the specific target of a number of vegetal and animal toxins which, by binding to the channel, alter its activity by affecting one or more of its properties. At least six toxin receptor sites have been identified on the neuronal Na channel on the basis of binding studies. However, only toxins interacting with four of these sites (sites 2, 3, 5 et 6) produce alterations of channel inactivation. The maximal percentage of Na channels modified by the binding of neurotoxins to sites 2 (batrachotoxin and some alkaloids), 3 (alpha-scorpion and sea anemone toxins), 5 (brevetoxins and ciguatoxins) et 6 (delta-conotoxins) is different according to the site considered. However, in all cases, these channels do not inactivate. Moreover, Na channels modified by toxins which bind to sites 2, 5 and 6 activate at membrane potentials more negative than do unmodified channels. The physiological consequences of Na channel modifications, induced by the binding of neurotoxins to sites 2, 3, 5 and 6, are (i) an inhibition of cellular excitability due to an important membrane depolarization (site 2), (ii) a decrease of cellular excitability due to an important increase in the action potential duration (site 3) and (iii) an increase in cellular excitability which results in spontaneous and repetitive firing of action potentials (sites 5 and 6). The biochemical and electrophysiological studies performed with these toxins, as well as the determination of their molecular structure, have given basic information on the function and structure of the Na channel protein. Therefore, various models representing the different states of Na channels have been proposed to account for the neurotoxin-induced modifications of Na inactivation. Moreover, the localization of receptor binding sites 2, 3, 5 et 6 for these toxins on the neuronal Na channel has been deduced and the molecular identification of the recognition site(s) for some of them has been established on the alpha sub-unit forming the Na channel protein.

CALIBRATION AND VALIDATION OF CONFOCAL SPECTRAL IMAGING SYSTEMS

EPA Science Inventory

Confocal spectral imaging (CSI) microscope systems now on the market can perform spectral characterization of biological specimens containing fluorescent proteins, labels or dyes. Some CSI have been found to present inconsistent spectral characterizations within a particular syst...

Charter Schools Indicators: A Report from the Center on Educational Governance, University of Southern California. CSI-USC 2008

ERIC Educational Resources Information Center

Center on Educational Governance, 2008

2008-01-01

This report, which is the second annual report on charter schools in California by the University of Southern California's (USC's) Center on Educational Governance, offers a unique view of charter school performance. Using both financial and academic data submitted by school districts to the state of California, this report looks well beyond test…

Hepatic fat quantification using automated six-point Dixon: Comparison with conventional chemical shift based sequences and computed tomography.

PubMed

Shimizu, Kie; Namimoto, Tomohiro; Nakagawa, Masataka; Morita, Kosuke; Oda, Seitaro; Nakaura, Takeshi; Utsunomiya, Daisuke; Yamashita, Yasuyuki

To compare automated six-point Dixon (6-p-Dixon) MRI comparing with dual-echo chemical-shift-imaging (CSI) and CT for hepatic fat fraction in phantoms and clinical study. Phantoms and fifty-nine patients were examined both MRI and CT for quantitative fat measurements. In phantom study, linear regression between fat concentration and 6-p-Dixon showed good agreement. In clinical study, linear regression between 6-p-Dixon and dual-echo CSI showed good agreement. CT attenuation value was strongly correlated with 6-p-Dixon (R 2 =0.852; P<0.001) and dual-echo CSI (R 2 =0.812; P<0.001). Automated 6-p-Dixon and dual-echo CSI were accurate correlation with CT attenuation value of liver parenchyma. 6-p-Dixon has the potential for automated hepatic fat quantification. Copyright © 2017 Elsevier Inc. All rights reserved.

Generation of CsI cluster ions for mass calibration in matrix-assisted laser desorption/ionization mass spectrometry.

PubMed

Lou, Xianwen; van Dongen, Joost L J; Meijer, E W

2010-07-01

A simple method was developed for the generation of cesium iodide (CsI) cluster ions up to m/z over 20,000 in matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS). Calibration ions in both positive and negative ion modes can readily be generated from a single MALDI spot of CsI(3) with 2-[(2E)-3-(4-tert-butylphenyl)-2-methylprop-2-enylidene] malononitrile (DCTB) matrix. The major cluster ion series observed in the positive ion mode is [(CsI)(n)Cs](+), and in the negative ion mode is [(CsI)(n)I](-). In both cluster series, ions spread evenly every 259.81 units. The easy method described here for the production of CsI cluster ions should be useful for MALDI MS calibrations. Copyright 2010 American Society for Mass Spectrometry. Published by Elsevier Inc. All rights reserved.

[Continuous subcutaneous infusion in palliative care, an undervalued method].

PubMed

van Marum, R J; de Vogel, E M; Zylicz, Z

2002-11-23

Three patients, 2 men aged 55 and 54 years and a woman aged 86 years, were admitted to hospital for treatment of symptoms resulting from terminal disease (pain, agitation, nausea etc.). In all three patients, continuous subcutaneous infusion (CSI) of medication was successfully used to control the symptoms. Compared with intravenous infusion, the technique of CSI is easy to learn and is associated with fewer complications. Its reliability and ease-of-use make it a technique that can be used not only in a hospital setting, but also in general practice and nursing homes. Medication used in palliative care (e.g. morphine, haloperidol, metoclopramide, levomepromazine, midazolam) can often be administered safely by CSI. In palliative care, where goals should be accomplished with minimal burden to the patient, CSI must be considered the technique of choice in patients who are unable to swallow their medication.

Mitigating mechanical failure of crystalline silicon electrodes for lithium batteries by morphological design [Morphological design of silicon electrode with anisotropic interface reaction rate for lithium ion batteries

DOE PAGES

An, Yonghao; Wood, Brandon C.; Ye, Jianchao; ...

2015-06-08

Although crystalline silicon (c-Si) anodes promise very high energy densities in Li-ion batteries, their practical use is complicated by amorphization, large volume expansion and severe plastic deformation upon lithium insertion. Recent experiments have revealed the existence of a sharp interface between crystalline Si (c-Si) and the amorphous Li xSi alloy during lithiation, which propagates with a velocity that is orientation dependent; the resulting anisotropic swelling generates substantial strain concentrations that initiate cracks even in nanostructured Si. Here we describe a novel strategy to mitigate lithiation-induced fracture by using pristine c-Si structures with engineered anisometric morphologies that are deliberately designed tomore » counteract the anisotropy in the crystalline/amorphous interface velocity. This produces a much more uniform volume expansion, significantly reducing strain concentration. Based on a new, validated methodology that improves previous models of anisotropic swelling of c-Si, we propose optimal morphological designs for c-Si pillars and particles. The advantages of the new morphologies are clearly demonstrated by mesoscale simulations and verified by experiments on engineered c-Si micropillars. The results of this study illustrate that morphological design is effective in improving the fracture resistance of micron-sized Si electrodes, which will facilitate their practical application in next-generation Li-ion batteries. In conclusion, the model and design approach present in this paper also have general implications for the study and mitigation of mechanical failure of electrode materials that undergo large anisotropic volume change upon ion insertion and extraction.« less

Association Analyses of RANKL/RANK/OPG Gene Polymorphisms with Femoral Neck Compression Strength Index Variation in Caucasians

PubMed Central

Dong, Shan-Shan; Liu, Xiao-Gang; Chen, Yuan; Guo, Yan; Wang, Liang; Zhao, Jian; Xiong, Dong-Hai; Xu, Xiang-Hong; Recker, Robert R.

2010-01-01

Femoral neck compression strength index (fCSI), a novel phenotypic parameter that integrates bone density, bone size, and body size, has significant potential to improve hip fracture risk assessment. The genetic factors underlying variations in fCSI, however, remain largely unknown. Given the important roles of the receptor activator of the nuclear factor-κB ligand/receptor activator of the nuclear factor-κB/osteoprotegerin (RANKL/RANK/OPG) pathway in the regulation of bone remodeling, we tested the associations between RANKL/RANK/OPG polymorphisms and variations in fCSI as well as its components (femoral neck bone mineral density [fBMD], femoral neck width [FNW], and weight). This was accomplished with a sample comprising 1873 subjects from 405 Caucasian nuclear families. Of the 37 total SNPs studied in these three genes, 3 SNPs, namely, rs12585014, rs7988338, and rs2148073, of RANKL were significantly associated with fCSI (P = 0.0007, 0.0007, and 0.0005, respectively) after conservative Bonferroni correction. Moreover, the three SNPs were approximately in complete linkage disequilibrium. Haplotype-based association tests corroborated the single-SNP results since haplotype 1 of block 1 of the RANKL gene achieved an even more significant association with fCSI (P = 0.0003) than any of the individual SNPs. However, we did not detect any significant associations of these genes with fBMD, FNW, or weight. In summary, our findings suggest that the RANKL gene may play an important role in variation in fCSI, independent of fBMD and non-fBMD components. PMID:19458885

A new ion selective electrode for cesium (I) based on calix[4]arene-crown-6 compounds.

PubMed

Ramanjaneyulu, P S; Kumar, Abha Naveen; Sayi, Y S; Ramakumar, K L; Nayak, S K; Chattopadhyay, S

2012-02-29

A polyvinylchloride (PVC) based liquid membrane ion selective electrode (ISE) for cesium has been developed. 25,27-Dihydroxycalix[4]arene-crown-6 (L1), 5,11,17,23-tetra-tert-butyl-25,27-dimethoxycalix[4]arene-crown-6 (L2) and 25,27-bis(1-octyloxy)calix[4]arene-crown-6 (L3) were investigated for their use as ionophores. The cation exchange resin DOWEX-50W was used to maintain low activity Cs+ in inner filling solution to improve the performance. The best response for cesium was observed with L3 along with optimized membrane constituents and composition. Excellent Nernstian response (56.6 mV/decade of Cs(I)) over the concentration range 10(-7) to 10(-2)M of Cs(I) was obtained with a fast response time of less than 10s. Detection limit for Cs(I) using the present ISE is 8.48×10(-8) M Cs(I). Separate solution method (SSM) was applied to ascertain the selectivity for Cs(I) over alkali, alkaline earth and transition metal ions. The response of ISE for Cs(I) was fairly constant over the pH range of 4-11. The lifetime of the electrode is 10 months which is the highest life for any membrane based Cs-ISE so far developed. The concentration of cesium ion in two simulated high level active waste streams was determined and results agreed well with those obtained independently employing AAS. Copyright © 2011 Elsevier B.V. All rights reserved.

Association analyses of RANKL/RANK/OPG gene polymorphisms with femoral neck compression strength index variation in Caucasians.

PubMed

Dong, Shan-Shan; Liu, Xiao-Gang; Chen, Yuan; Guo, Yan; Wang, Liang; Zhao, Jian; Xiong, Dong-Hai; Xu, Xiang-Hong; Recker, Robert R; Deng, Hong-Wen

2009-08-01

Femoral neck compression strength index (fCSI), a novel phenotypic parameter that integrates bone density, bone size, and body size, has significant potential to improve hip fracture risk assessment. The genetic factors underlying variations in fCSI, however, remain largely unknown. Given the important roles of the receptor activator of the nuclear factor-kappaB ligand/receptor activator of the nuclear factor-kappaB/osteoprotegerin (RANKL/RANK/OPG) pathway in the regulation of bone remodeling, we tested the associations between RANKL/RANK/OPG polymorphisms and variations in fCSI as well as its components (femoral neck bone mineral density [fBMD], femoral neck width [FNW], and weight). This was accomplished with a sample comprising 1873 subjects from 405 Caucasian nuclear families. Of the 37 total SNPs studied in these three genes, 3 SNPs, namely, rs12585014, rs7988338, and rs2148073, of RANKL were significantly associated with fCSI (P = 0.0007, 0.0007, and 0.0005, respectively) after conservative Bonferroni correction. Moreover, the three SNPs were approximately in complete linkage disequilibrium. Haplotype-based association tests corroborated the single-SNP results since haplotype 1 of block 1 of the RANKL gene achieved an even more significant association with fCSI (P = 0.0003) than any of the individual SNPs. However, we did not detect any significant associations of these genes with fBMD, FNW, or weight. In summary, our findings suggest that the RANKL gene may play an important role in variation in fCSI, independent of fBMD and non-fBMD components.

Investigating the chemical mist deposition technique for poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) on textured crystalline-silicon for organic/crystalline-silicon heterojunction solar cells

NASA Astrophysics Data System (ADS)

Hossain, Jaker; Ohki, Tatsuya; Ichikawa, Koki; Fujiyama, Kazuhiko; Ueno, Keiji; Fujii, Yasuhiko; Hanajiri, Tatsuro; Shirai, Hajime

2016-03-01

Chemical mist deposition (CMD) of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) was investigated in terms of cavitation frequency f, solvent, flow rate of nitrogen, substrate temperature Ts, and substrate dc bias Vs as variables for efficient PEDOT:PSS/crystalline silicon (c-Si) heterojunction solar cells. The high-speed-camera and differential mobility analysis characterizations revealed that the average size and flux of PEDOT:PSS mist depend on f, type of solvent, and Vs. Film deposition occurred when positive Vs was applied to the c-Si substrate at Ts of 30-40 °C, whereas no deposition of films occurred with negative Vs, implying that the film is deposited mainly from negatively charged mist. The uniform deposition of PEDOT:PSS films occurred on textured c-Si(100) substrates by adjusting Ts and Vs. The adhesion of CMD PEDOT:PSS film to c-Si was greatly enhanced by applying substrate dc bias Vs compared with that of spin-coated film. The CMD PEDOT:PSS/c-Si heterojunction solar cell devices on textured c-Si(100) in 2 × 2 cm2 exhibited a power conversion efficiency η of 11.0% with better uniformity of the solar cell parameters. Furthermore, η was increased to 12.5% by adding an AR coating layer of molybdenum oxide MoOx formed by CMD. These findings suggest that CMD with negatively charged mist has great potential for the uniform deposition of organic and inorganic materials on textured c-Si substrates by suitably adjusting Ts and Vs.

Bioactive glass-reinforced bioceramic ink writing scaffolds: sintering, microstructure and mechanical behavior.

PubMed

Shao, Huifeng; Yang, Xianyan; He, Yong; Fu, Jianzhong; Liu, Limin; Ma, Liang; Zhang, Lei; Yang, Guojing; Gao, Changyou; Gou, Zhongru

2015-09-10

The densification of pore struts in bioceramic scaffolds is important for structure stability and strength reliability. An advantage of ceramic ink writing is the precise control over the microstructure and macroarchitecture. However, the use of organic binder in such ink writing process would heavily affect the densification of ceramic struts and sacrifice the mechanical strength of porous scaffolds after sintering. This study presents a low-melt-point bioactive glass (BG)-assisted sintering strategy to overcome the main limitations of direct ink writing (extrusion-based three-dimensional printing) and to produce high-strength calcium silicate (CSi) bioceramic scaffolds. The 1% BG-added CSi (CSi-BG1) scaffolds with rectangular pore morphology sintered at 1080 °C have a very small BG content, readily induce apatite formation, and show appreciable linear shrinkage (∼21%), which is consistent with the composite scaffolds with less or more BG contents sintered at either the same or a higher temperature. These CSi-BG1 scaffolds also possess a high elastic modulus (∼350 MPa) and appreciable compressive strength (∼48 MPa), and show significant strength enhancement after exposure to simulated body fluid-a performance markedly superior to those of pure CSi scaffolds. Particularly, the honeycomb-pore CSi-BG1 scaffolds show markedly higher compressive strength (∼88 MPa) than the scaffolds with rectangular, parallelogram, and Archimedean chord pore structures. It is suggested that this approach can potentially facilitate the translation of ceramic ink writing and BG-assisted sintering of bioceramic scaffold technologies to the in situ bone repair.

NIFLUMIC ACID BLOCKS NATIVE AND RECOMBINANT T-TYPE CHANNELS

PubMed Central

Balderas, E; Arteaga-Tlecuitl, R; Rivera, M; Gomora, JC; Darszon, A

2012-01-01

Voltage-dependent calcium channels are widely distributed in animal cells, including spermatozoa. Calcium is fundamental in many sperm functions such as: motility, capacitation and the acrosome reaction, all essential for fertilization. Pharmacological evidence has suggested T-type calcium channels participate in the acrosome reaction. Niflumic acid (NA), a non-steroidal anti-inflammatory drug commonly used as chloride channel blocker, blocks T-currents in mouse spermatogenic cells and Cl− channels in testicular sperm. Here we examine the mechanism of NA blockade and explore if it can be used to separate the contribution of different CaV3 members previously detected in these cells. Electrophysiological patch-clamp recordings were performed in isolated mouse spermatogenic cells and in HEK cells heterologously expressing CaV3 channels. NA blocks mouse spermatogenic cell T-type currents with an IC50 of 73.5 µM, without major voltage-dependent effects. The NA blockade is more potent in the open and in the inactivated state than in the closed state of the T-type channels. Interestingly, we found that heterologously expressed CaV3.1 and CaV3.3 channels were more sensitive to NA than CaV3.2 channels, and this drug substantially slowed the recovery from inactivation of the three isoforms. Molecular docking modeling of drug-channel binding predicts that NA binds preferentially to the extracellular face of CaV3.1 channels. The biophysical characteristics of mouse spermatogenic cell T-type currents more closely resemble those from heterologously expressed CaV3.1 channels, including their sensitivity to NA. As CaV3.1 null mice maintain their spermatogenic cell T-currents, it is likely that a novel CaV3.2 isoform is responsible for them. PMID:21898399

Protective effect of inactivated hepatitis A vaccine against the outbreak of hepatitis A in an open rural community

PubMed Central

Shen, Yue-Gen; Gu, Xie-Jun; Zhou, Jian-Hong

2008-01-01

AIM: To evaluate the protective effect of inactivated hepatitis A vaccine (Healive®) against hepatitis A outbreak in an emergency vaccination campaign. METHODS: During an outbreak of hepatitis A in Honghe Town, Xiuzhou District, Jiaxing City, Zhejiang Province, two nonrandomized controlled trials were conducted in September 2006. The first trial was to vaccinate 108 anti-HAV negative individuals with close contacts of the patients from September with 1 dose of an inactivated hepatitis A vaccine, Healive®. The control group comprised of 115 individuals with close contacts of the patients before September. The second trial was to vaccinate 3365 primary and secondary school students who volunteered to receive a dose of Healive® and 2572 students who did not receive Healive® serving as its controls. An epidemiological survey was conducted to evaluate the protective efficacy of the vaccine. RESULTS: A total of 136 hepatitis A cases were reported during an outbreak that started in June, peaked in August and September, and ended after December of 2006. After a massive vaccination of school children in September, the number of cases declined significantly. No hepatitis A was detected in the 108 vaccinated individuals with close contacts of patients, whereas 4 cases of hepatitis A were found in the controls. The infection rate of hepatitis A was not significantly different in the individuals with close contacts of patients whether or not they received the vaccine (P = 0.122). No hepatitis A was detected in the 3365 students who received the vaccine, four cases of hepatitis A were found in the controls. The infection rate of students with or without vaccination was significantly different in the students who received the vaccine (0/3365 vs 4/2572, P = 0.035). The protective efficacy of the vaccine was 100%. CONCLUSION: Inactivated hepatitis A vaccine demonstrates a good protective effect against an outbreak of hepatitis A. PMID:18461664

WAVELENGTH AND ALIGNMENT TESTS FOR CONFOCAL SPECTRAL IMAGING SYSTEMS

EPA Science Inventory

Confocal spectral imaging (CSI) microscope systems now on the market delineate multiple fluorescent proteins, labels, or dyes within biological specimens by performing spectral characterizations. However, we find that some CSI present inconsistent spectral profiles of reference s...

Cesium iodide alloys

DOEpatents

Kim, H.E.; Moorhead, A.J.

1992-12-15

A transparent, strong CsI alloy is described having additions of monovalent iodides. Although the preferred iodide is AgI, RbI and CuI additions also contribute to an improved polycrystalline CsI alloy with outstanding multispectral infrared transmittance properties. 6 figs.

[Inactivation and reactivation of antibiotic-resistant bacteria during and after UV disinfection in reclaimed water].

PubMed

Huang, Jing-Jing; Tang, Fang; Xi, Jin-Ying; Pang, Yu-Chen; Hu, Hong-Ying

2014-04-01

Prevalence of antibiotic-resistant bacteria in wastewater effluents is concerned as an emerging contaminant. To estimate inactivation and reactivation potentials of antibiotic-resistant bacteria by UV disinfection, inactivation and reactivation of penicillin-, ampicillin-, cephalexin-, chloramphenicol-and rifampicin-resistant bacteria in the secondary effluent were studied under different UV doses. The results showed that the inactivation ratios of penicillin-, ampicillin-, cephalexin-and chloramphenicol-resistant bacteria were higher than 4-log, which was closed to that of total heterotrophic bacteria; however, the inactivation ratio of rifampicin-resistant bacteria was lower (3.7-log) under 20 mJ x cm(-2) UV exposure. After 22 h standing incubation, antibiotic-resistant bacteria widely reactivated. The colony forming ability of antibiotic-resistant bacteria was as high as 3-log when exposed to 20 mJ x cm(-2) UV light. Hence, conventional UV dose can not effectively control reactivation of antibiotic-resistant bacteria in reclaimed water by UV disinfection.

Multi-diversity combining and selection for relay-assisted mixed RF/FSO system

NASA Astrophysics Data System (ADS)

Chen, Li; Wang, Weidong

2017-12-01

We propose and analyze multi-diversity combining and selection to enhance the performance of relay-assisted mixed radio frequency/free-space optics (RF/FSO) system. We focus on a practical scenario for cellular network where a single-antenna source is communicating to a multi-apertures destination through a relay equipped with multiple receive antennas and multiple transmit apertures. The RF single input multiple output (SIMO) links employ either maximal-ratio combining (MRC) or receive antenna selection (RAS), and the FSO multiple input multiple output (MIMO) links adopt either repetition coding (RC) or transmit laser selection (TLS). The performance is evaluated via an outage probability analysis over Rayleigh fading RF links and Gamma-Gamma atmospheric turbulence FSO links with pointing errors where channel state information (CSI) assisted amplify-and-forward (AF) scheme is considered. Asymptotic closed-form expressions at high signal-to-noise ratio (SNR) are also derived. Coding gain and diversity order for different combining and selection schemes are further discussed. Numerical results are provided to verify and illustrate the analytical results.

On base station cooperation using statistical CSI in jointly correlated MIMO downlink channels

NASA Astrophysics Data System (ADS)

Zhang, Jun; Jiang, Bin; Jin, Shi; Gao, Xiqi; Wong, Kai-Kit

2012-12-01

This article studies the transmission of a single cell-edge user's signal using statistical channel state information at cooperative base stations (BSs) with a general jointly correlated multiple-input multiple-output (MIMO) channel model. We first present an optimal scheme to maximize the ergodic sum capacity with per-BS power constraints, revealing that the transmitted signals of all BSs are mutually independent and the optimum transmit directions for each BS align with the eigenvectors of the BS's own transmit correlation matrix of the channel. Then, we employ matrix permanents to derive a closed-form tight upper bound for the ergodic sum capacity. Based on these results, we develop a low-complexity power allocation solution using convex optimization techniques and a simple iterative water-filling algorithm (IWFA) for power allocation. Finally, we derive a necessary and sufficient condition for which a beamforming approach achieves capacity for all BSs. Simulation results demonstrate that the upper bound of ergodic sum capacity is tight and the proposed cooperative transmission scheme increases the downlink system sum capacity considerably.

Performance Analysis of Physical Layer Security of Opportunistic Scheduling in Multiuser Multirelay Cooperative Networks

PubMed Central

Shim, Kyusung; Do, Nhu Tri; An, Beongku

2017-01-01

In this paper, we study the physical layer security (PLS) of opportunistic scheduling for uplink scenarios of multiuser multirelay cooperative networks. To this end, we propose a low-complexity, yet comparable secrecy performance source relay selection scheme, called the proposed source relay selection (PSRS) scheme. Specifically, the PSRS scheme first selects the least vulnerable source and then selects the relay that maximizes the system secrecy capacity for the given selected source. Additionally, the maximal ratio combining (MRC) technique and the selection combining (SC) technique are considered at the eavesdropper, respectively. Investigating the system performance in terms of secrecy outage probability (SOP), closed-form expressions of the SOP are derived. The developed analysis is corroborated through Monte Carlo simulation. Numerical results show that the PSRS scheme significantly improves the secure ability of the system compared to that of the random source relay selection scheme, but does not outperform the optimal joint source relay selection (OJSRS) scheme. However, the PSRS scheme drastically reduces the required amount of channel state information (CSI) estimations compared to that required by the OJSRS scheme, specially in dense cooperative networks. PMID:28212286

Comparison of Gating Properties and Use-Dependent Block of Nav1.5 and Nav1.7 Channels by Anti-Arrhythmics Mexiletine and Lidocaine

PubMed Central

Wang, Ying; Mi, Jianxun; Lu, Ka; Lu, Yanxin; Wang, KeWei

2015-01-01

Mexiletine and lidocaine are widely used class IB anti-arrhythmic drugs that are considered to act by blocking voltage-gated open sodium currents for treatment of ventricular arrhythmias and relief of pain. To gain mechanistic insights into action of anti-arrhythmics, we characterized biophysical properties of Nav1.5 and Nav1.7 channels stably expressed in HEK293 cells and compared their use-dependent block in response to mexiletine and lidocaine using whole-cell patch clamp recordings. While the voltage-dependent activation of Nav1.5 or Nav1.7 was not affected by mexiletine and lidocaine, the steady-state fast and slow inactivation of Nav1.5 and Nav1.7 were significantly shifted to hyperpolarized direction by either mexiletine or lidocaine in dose-dependent manner. Both mexiletine and lidocaine enhanced the slow component of closed-state inactivation, with mexiletine exerting stronger inhibition on either Nav1.5 or Nav1.7. The recovery from inactivation of Nav1.5 or Nav1.7 was significantly prolonged by mexiletine compared to lidocaine. Furthermore, mexiletine displayed a pronounced and prominent use-dependent inhibition of Nav1.5 than lidocaine, but not Nav1.7 channels. Taken together, our findings demonstrate differential responses to blockade by mexiletine and lidocaine that preferentially affect the gating of Nav1.5, as compared to Nav1.7; and mexiletine exhibits stronger use-dependent block of Nav1.5. The differential gating properties of Nav1.5 and Nav1.7 in response to mexiletine and lidocaine may help explain the drug effectiveness and advance in new designs of safe and specific sodium channel blockers for treatment of cardiac arrhythmia or pain. PMID:26068619

Highly efficient holograms based on c-Si metasurfaces in the visible range.

PubMed

Martins, Augusto; Li, Juntao; da Mota, Achiles F; Wang, Yin; Neto, Luiz G; do Carmo, João P; Teixeira, Fernando L; Martins, Emiliano R; Borges, Ben-Hur V

2018-04-16

This paper reports on the first hologram in transmission mode based on a c-Si metasurface in the visible range. The hologram shows high fidelity and high efficiency, with measured transmission and diffraction efficiencies of ~65% and ~40%, respectively. Although originally designed to achieve full phase control in the range [0-2π] at 532 nm, these holograms have also performed well at 444.9 nm and 635 nm. The high tolerance to both fabrication and wavelength variations demonstrate that holograms based on c-Si metasurfaces are quite attractive for diffractive optics applications, and particularly for full-color holograms.

CSI-EPT in Presence of RF-Shield for MR-Coils.

PubMed

Arduino, Alessandro; Zilberti, Luca; Chiampi, Mario; Bottauscio, Oriano

2017-07-01

Contrast source inversion electric properties tomography (CSI-EPT) is a recently developed technique for the electric properties tomography that recovers the electric properties distribution starting from measurements performed by magnetic resonance imaging scanners. This method is an optimal control approach based on the contrast source inversion technique, which distinguishes itself from other electric properties tomography techniques for its capability to recover also the local specific absorption rate distribution, essential for online dosimetry. Up to now, CSI-EPT has only been described in terms of integral equations, limiting its applicability to homogeneous unbounded background. In order to extend the method to the presence of a shield in the domain-as in the recurring case of shielded radio frequency coils-a more general formulation of CSI-EPT, based on a functional viewpoint, is introduced here. Two different implementations of CSI-EPT are proposed for a 2-D transverse magnetic model problem, one dealing with an unbounded domain and one considering the presence of a perfectly conductive shield. The two implementations are applied on the same virtual measurements obtained by numerically simulating a shielded radio frequency coil. The results are compared in terms of both electric properties recovery and local specific absorption rate estimate, in order to investigate the requirement of an accurate modeling of the underlying physical problem.

A Clinical Evaluation of the Competing Sources of Input Hypothesis

PubMed Central

Leonard, Laurence B.; Bredin-Oja, Shelley L.; Deevy, Patricia

2017-01-01

Purpose Our purpose was to test the competing sources of input (CSI) hypothesis by evaluating an intervention based on its principles. This hypothesis proposes that children's use of main verbs without tense is the result of their treating certain sentence types in the input (e.g., Was she laughing ?) as models for declaratives (e.g., She laughing). Method Twenty preschoolers with specific language impairment were randomly assigned to receive either a CSI-based intervention or a more traditional intervention that lacked the novel CSI features. The auxiliary is and the third-person singular suffix –s were directly treated over a 16-week period. Past tense –ed was monitored as a control. Results The CSI-based group exhibited greater improvements in use of is than did the traditional group (d = 1.31), providing strong support for the CSI hypothesis. There were no significant between-groups differences in the production of the third-person singular suffix –s or the control (–ed), however. Conclusions The group differences in the effects on the 2 treated morphemes may be due to differences in their distribution in interrogatives and declaratives (e.g., Is he hiding/He is hiding vs. Does he hide/He hide s). Refinements in the intervention could address this issue and lead to more general effects across morphemes. PMID:28114610

Properties of an intermediate-duration inactivation process of the voltage-gated sodium conductance in rat hippocampal CA1 neurons.

PubMed

French, Christopher R; Zeng, Zhen; Williams, David A; Hill-Yardin, Elisa L; O'Brien, Terence J

2016-02-01

Rapid transmembrane flow of sodium ions produces the depolarizing phase of action potentials (APs) in most excitable tissue through voltage-gated sodium channels (NaV). Macroscopic currents display rapid activation followed by fast inactivation (IF) within milliseconds. Slow inactivation (IS) has been subsequently observed in several preparations including neuronal tissues. IS serves important physiological functions, but the kinetic properties are incompletely characterized, especially the operative timescales. Here we present evidence for an "intermediate inactivation" (II) process in rat hippocampal CA1 neurons with time constants of the order of 100 ms. The half-inactivation potentials (V0.5) of steady-state inactivation curves were hyperpolarized by increasing conditioning pulse duration from 50 to 500 ms and could be described by a sum of Boltzmann relations. II state transitions were observed after opening as well as subthreshold potentials. Entry into II after opening was relatively insensitive to membrane potential, and recovery of II became more rapid at hyperpolarized potentials. Removal of fast inactivation with cytoplasmic papaine revealed time constants of INa decay corresponding to II and IS with long depolarizations. Dynamic clamp revealed attenuation of trains of APs over the 10(2)-ms timescale, suggesting a functional role of II in repetitive firing accommodation. These experimental findings could be reproduced with a five-state Markov model. It is likely that II affects important aspects of hippocampal neuron response and may provide a drug target for sodium channel modulation. Copyright © 2016 the American Physiological Society.

Assessing the Geomorphic Evolution and Hydrographic Changes Induced by Winter Storms along the Louisiana Coast

NASA Technical Reports Server (NTRS)

Menzel, W. Paul; Moeller, Christopher, C; Huh, Oscar K.; Roberts, Harry H.

1998-01-01

The influence that cold front passages have on Louisiana coastal environments, including land loss and land building processes, has been the primary topic of this multidisciplinary research. This research has combined meteorological, remote sensing, and coastal expertise from the University of Wisconsin (UW) and Louisiana State University (LSU). Analyzed data sets include remotely sensed radiometric data (AVHRR on NOAA-12,13,14, Multispectral Atmospheric Mapping Sensor (MAMS) and MODIS Airborne Simulator (MAS) on NASA ER-2), U.S. Army Corps of Engineers (USACE) water level data, water quality data from the Coastal Studies Institute (CSI) at LSU, USACE river discharge data, National Weather Service (NWS) and CSI wind in sitzi measurements, geomorphic measurements from aerial photography (NASA ER-2 and Learjet), and CSI ground based sediment burial pipes (for monitoring topographic change along the Louisiana coast) and sediment cores. The work reported here-in is a continuation of an initial investigation into coastal Louisiana landform modification by cold front systems. That initial effort demonstrated the importance of cold front winds in the Atchafalaya Bay sediment plume distribution (Moeller et al.), documented the sediment transport and deposition process of the western Louisiana coast (Huh et al.) and developed tools (e.g. water types identification, suspended solids estimation) from multispectral radiometric data for application to the current study. This study has extended that work, developing a Geomorphic Impact Index (GI(sup 2)) for relating atmospheric forcing to coastal response and new tools to measure water motion and sediment transport.

Characterization of two distinct depolarization-activated K+ currents in isolated adult rat ventricular myocytes

PubMed Central

1991-01-01

Depolarization-activated outward K+ currents in isolated adult rat ventricular myocytes were characterized using the whole-cell variation of the patch-clamp recording technique. During brief depolarizations to potentials positive to -40 mV, Ca(2+)-independent outward K+ currents in these cells rise to a transient peak, followed by a slower decay to an apparent plateau. The analyses completed here reveal that the observed outward current waveforms result from the activation of two kinetically distinct voltage-dependent K+ currents: one that activates and inactivates rapidly, and one that activates and inactivates slowly, on membrane depolarization. These currents are referred to here as Ito (transient outward) and IK (delayed rectifier), respectively, because their properties are similar (although not identical) to these K+ current types in other cells. Although the voltage dependences of Ito and IK activation are similar, Ito activates approximately 10-fold and inactivates approximately 30-fold more rapidly than IK at all test potentials. In the composite current waveforms measured during brief depolarizations, therefore, the peak current predominantly reflects Ito, whereas IK is the primary determinant of the plateau. There are also marked differences in the voltage dependences of steady-state inactivation of these two K+ currents: IK undergoes steady-state inactivation at all potentials positive to -120 mV, and is 50% inactivated at -69 mV; Ito, in contrast, is insensitive to steady-state inactivation at membrane potentials negative to -50 mV. In addition, Ito recovers from steady-state inactivation faster than IK: at -90 mV, for example, approximately 70% recovery from the inactivation produced at -20 mV is observed within 20 ms for Ito; IK recovers approximately 25-fold more slowly. The pharmacological properties of Ito and IK are also distinct: 4-aminopyridine preferentially attenuates Ito, and tetraethylammonium suppresses predominantly IK. The voltage- and time- dependent properties of these currents are interpreted here in terms of a model in which Ito underlies the initial, rapid repolarization phase of the action potential (AP), and IK is responsible for the slower phase of AP repolarization back to the resting membrane potential, in adult rat ventricular myocytes. PMID:1865177

Integrating Computer-Mediated Communication Strategy Instruction

ERIC Educational Resources Information Center

McNeil, Levi

2016-01-01

Communication strategies (CSs) play important roles in resolving problematic second language interaction and facilitating language learning. While studies in face-to-face contexts demonstrate the benefits of communication strategy instruction (CSI), there have been few attempts to integrate computer-mediated communication and CSI. The study…

Key Features of High-Quality Policies and Guidelines to Support Social and Emotional Learning: Recommendations and Examples for the Collaborating States Initiative (CSI)

ERIC Educational Resources Information Center

Dusenbury, Linda; Yoder, Nick

2017-01-01

The current document serves two purposes. First, it provides an overview of six key features of a high-quality, comprehensive package of policies and guidance to support student social and emotional learning (SEL). These features are based on Collaborative for Academic Social, and Emotional Learning's (CASEL's) review of the research literature on…

Treatment of periodontal disease with an Er,Cr:YSGG laser in rats exposed to cigarette smoke inhalation.

PubMed

Pavone, Chaine; Nogueira, Andressa Vilas Boas; de Oliveira, Guilherme José Pimentel Lopes; Scardueli, Cássio Rocha; Cerri, Paulo Sérgio; Marcantonio, Elcio; Marcantonio, Rosemary Adriana Chiérici

2015-11-01

The purpose of this study was to evaluate the erbium, chromium:yttrium-scandiumgallium-garnet (Er,Cr:YSGG) laser irradiation in the treatment of periodontitis in rats exposed to cigarette smoke inhalation (CSI). Ligatures were placed in the maxillary second molars. After a 15-day period, the ligatures were removed and 180 animals were randomly divided into six groups: (1) CSRP group--CSI and manual scaling and root planing (SRP) treatment; (2) CL group--CSI and Er,Cr:YSGG laser irradiation; (3) CSRP + L group-CSI, SRP, and Er,Cr:YSGG irradiation; (4) SRP group-manual SRP; (5) L group--Er,Cr:YSGG irradiation; (6) SRP + L group--SRP and Er,Cr:YSGG irradiation. At 7, 15, and 30 days after treatments, animals were euthanized and histologic, histometric, immunohistochemistry, and real-time PCR analyses were performed. Histometrically, no differences were observed in the SRP, L, and SRP + L groups exposed to CSI. The CSRP group showed more bone formation at 30 days than at 15 days (p < 0.01) but less bone at 30 days than the CL group at 30 days (p < 0.05). Immunohistochemical staining was positive for osteoblasts, fibroblasts, and osteoclasts. Real-time PCR showed more (vascular endothelial growth factor) VEGF expression in the L (p < 0.05) and SRP + L (p < 0.01) groups at 30 days than at 15 days and less VEGF expression in the CSRP group at 30 days than at 15 days (p < 0.05). There was no difference in fibroblast growth factor (FGF) expression. The Er,Cr:YSGG laser irradiation promotes favorable conditions for tissue repair even in animals exposed to CSI, with similar results as those achieved from manual scaling and root planing.

Language production in a shared task: Cumulative Semantic Interference from self- and other-produced context words.

PubMed

Hoedemaker, Renske S; Ernst, Jessica; Meyer, Antje S; Belke, Eva

2017-01-01

This study assessed the effects of semantic context in the form of self-produced and other-produced words on subsequent language production. Pairs of participants performed a joint picture naming task, taking turns while naming a continuous series of pictures. In the single-speaker version of this paradigm, naming latencies have been found to increase for successive presentations of exemplars from the same category, a phenomenon known as Cumulative Semantic Interference (CSI). As expected, the joint-naming task showed a within-speaker CSI effect, such that naming latencies increased as a function of the number of category exemplars named previously by the participant (self-produced items). Crucially, we also observed an across-speaker CSI effect, such that naming latencies slowed as a function of the number of category members named by the participant's task partner (other-produced items). The magnitude of the across-speaker CSI effect did not vary as a function of whether or not the listening participant could see the pictures their partner was naming. The observation of across-speaker CSI suggests that the effect originates at the conceptual level of the language system, as proposed by Belke's (2013) Conceptual Accumulation account. Whereas self-produced and other-produced words both resulted in a CSI effect on naming latencies, post-experiment free recall rates were higher for self-produced than other-produced items. Together, these results suggest that both speaking and listening result in implicit learning at the conceptual level of the language system but that these effects are independent of explicit learning as indicated by item recall. Copyright © 2016 Elsevier B.V. All rights reserved.

Imaging responses of on-site CsI and Gd2O2S flat-panel detectors: Dependence on the tube voltage

NASA Astrophysics Data System (ADS)

Jeon, Hosang; Chung, Myung Jin; Youn, Seungman; Nam, Jiho; Lee, Jayoung; Park, Dahl; Kim, Wontaek; Ki, Yongkan; Kim, Ho Kyung

2015-07-01

One of the emerging issues in radiography is low-dose imaging to minimize patient's exposure. The scintillating materials employed in most indirect flat-panel detectors show a drastic change of X-ray photon absorption efficiency around their K-edge energies that consequently affects image quality. Using various tube voltages, we investigated the imaging performance of most popular scintillators: cesium iodide (CsI) and gadolinium oxysulfide (Gd2O2S). The integrated detective quantum efficiencies (iDQE) of four detectors installed in the same hospital were evaluated according to the standardized procedure IEC 62220-1 at tube voltages of 40 - 120 kVp. The iDQE values of the Gd2O2S detectors were normalized by those of CsI detectors to exclude the effects of image postprocessing. The contrast-to-noise ratios (CNR) were also evaluated by using an anthropomorphic chest phantom. The iDQE of the CsI detector outperformed that of the Gd2O2S detector over all tube voltages. Moreover, we noted that the iDQE of the Gd2O2S detectors quickly rolled off with decreasing tube voltage under 70 kVp. The CNRs of the two scintillators were similar at 120 kVp. At 60 kVp, however, the CNR of Gd2O2S was about half that of CsI. Compared to the Gd2O2S detectors, variations in the DQE performance of the CsI detectors were relatively immune to variations in the applied tube voltages. Therefore, we claim that Gd2O2S detectors are inappropriate for use in low-tube-voltage imaging (e.g., extremities and pediatrics) with low patient exposure.

Low Yield of Paired Head and Cervical Spine Computed Tomography in Blunt Trauma Evaluation.

PubMed

Graterol, Joseph; Beylin, Maria; Whetstone, William D; Matzoll, Ashleigh; Burke, Rennie; Talbott, Jason; Rodriguez, Robert M

2018-06-01

With increased computed tomography (CT) utilization, clinicians may simultaneously order head and neck CT scans, even when injury is suspected only in one region. We sought to determine: 1) the frequency of simultaneous ordering of a head CT scan when a neck CT scan is ordered; 2) the yields of simultaneously ordered head and neck CT scans for clinically significant injury (CSI); and 3) whether injury in one region is associated with a higher rate of injury in the other. This was a retrospective study of all adult patients who received neck CT scans (and simultaneously ordered head CT scans) as part of their blunt trauma evaluation at an urban level 1 trauma center in 2013. An expert panel determined CSI of head and neck injuries. We defined yield as number of patients with injury/number of patients who had a CT scan. Of 3223 patients who met inclusion criteria, 2888 (89.6%) had simultaneously ordered head and neck CT scans. CT yield for CSI in both the head and neck was 0.5% (95% confidence interval [CI] 0.3-0.8%), and the yield for any injury in both the head and neck was 1.4% (95% CI 1.0-1.8%). The yield for CSI in one region was higher when CSI was seen in the other region. The yield of CT for CSI in both the head and neck concomitantly is very low. When injury is seen in one region, there is higher likelihood of injury in the other. These findings argue against paired ordering of head and neck CT scans and suggest that CT scans should be ordered individually or when injury is detected in one region. Copyright © 2018 Elsevier Inc. All rights reserved.

Quantitatively probing propensity for structural transitions in engineered virus nanoparticles by single-molecule mechanical analysis

NASA Astrophysics Data System (ADS)

Castellanos, Milagros; Carrillo, Pablo J. P.; Mateu, Mauricio G.

2015-03-01

Viruses are increasingly being studied from the perspective of fundamental physics at the nanoscale as biologically evolved nanodevices with many technological applications. In viral particles of the minute virus of mice (MVM), folded segments of the single-stranded DNA genome are bound to the capsid inner wall and act as molecular buttresses that increase locally the mechanical stiffness of the particle. We have explored whether a quantitative linkage exists in MVM particles between their DNA-mediated stiffening and impairment of a heat-induced, virus-inactivating structural change. A series of structurally modified virus particles with disrupted capsid-DNA interactions and/or distorted capsid cavities close to the DNA-binding sites were engineered and characterized, both in classic kinetics assays and by single-molecule mechanical analysis using atomic force microscopy. The rate constant of the virus inactivation reaction was found to decrease exponentially with the increase in elastic constant (stiffness) of the regions closer to DNA-binding sites. The application of transition state theory suggests that the height of the free energy barrier of the virus-inactivating structural transition increases linearly with local mechanical stiffness. From a virological perspective, the results indicate that infectious MVM particles may have acquired the biological advantage of increased survival under thermal stress by evolving architectural elements that rigidify the particle and impair non-productive structural changes. From a nanotechnological perspective, this study provides proof of principle that determination of mechanical stiffness and its manipulation by protein engineering may be applied for quantitatively probing and tuning the conformational dynamics of virus-based and other protein-based nanoassemblies.Viruses are increasingly being studied from the perspective of fundamental physics at the nanoscale as biologically evolved nanodevices with many technological applications. In viral particles of the minute virus of mice (MVM), folded segments of the single-stranded DNA genome are bound to the capsid inner wall and act as molecular buttresses that increase locally the mechanical stiffness of the particle. We have explored whether a quantitative linkage exists in MVM particles between their DNA-mediated stiffening and impairment of a heat-induced, virus-inactivating structural change. A series of structurally modified virus particles with disrupted capsid-DNA interactions and/or distorted capsid cavities close to the DNA-binding sites were engineered and characterized, both in classic kinetics assays and by single-molecule mechanical analysis using atomic force microscopy. The rate constant of the virus inactivation reaction was found to decrease exponentially with the increase in elastic constant (stiffness) of the regions closer to DNA-binding sites. The application of transition state theory suggests that the height of the free energy barrier of the virus-inactivating structural transition increases linearly with local mechanical stiffness. From a virological perspective, the results indicate that infectious MVM particles may have acquired the biological advantage of increased survival under thermal stress by evolving architectural elements that rigidify the particle and impair non-productive structural changes. From a nanotechnological perspective, this study provides proof of principle that determination of mechanical stiffness and its manipulation by protein engineering may be applied for quantitatively probing and tuning the conformational dynamics of virus-based and other protein-based nanoassemblies. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr07046a

Robust Indoor Human Activity Recognition Using Wireless Signals.

PubMed

Wang, Yi; Jiang, Xinli; Cao, Rongyu; Wang, Xiyang

2015-07-15

Wireless signals-based activity detection and recognition technology may be complementary to the existing vision-based methods, especially under the circumstance of occlusions, viewpoint change, complex background, lighting condition change, and so on. This paper explores the properties of the channel state information (CSI) of Wi-Fi signals, and presents a robust indoor daily human activity recognition framework with only one pair of transmission points (TP) and access points (AP). First of all, some indoor human actions are selected as primitive actions forming a training set. Then, an online filtering method is designed to make actions' CSI curves smooth and allow them to contain enough pattern information. Each primitive action pattern can be segmented from the outliers of its multi-input multi-output (MIMO) signals by a proposed segmentation method. Lastly, in online activities recognition, by selecting proper features and Support Vector Machine (SVM) based multi-classification, activities constituted by primitive actions can be recognized insensitive to the locations, orientations, and speeds.

Electrical response of electron selective atomic layer deposited TiO2‑x heterocontacts on crystalline silicon substrates

NASA Astrophysics Data System (ADS)

Ahiboz, Doğuşcan; Nasser, Hisham; Aygün, Ezgi; Bek, Alpan; Turan, Raşit

2018-04-01

Integration of oxygen deficient sub-stoichiometric titanium dioxide (TiO2‑x) thin films as the electron transporting-hole blocking layer in solar cell designs are expected to reduce fabrication costs by eliminating high temperature processes while maintaining high conversion efficiencies. In this paper, we conducted a study to reveal the electrical properties of TiO2‑x thin films grown on crystalline silicon (c-Si) substrates by atomic layer deposition (ALD) technique. Effect of ALD substrate temperature, post deposition annealing, and doping type of the c-Si substrate on the interface states and TiO2‑x bulk properties were extracted by performing admittance (C-V, G-V) and current-voltage (J-V) measurements. Moreover, the asymmetry in C-V and J-V measurements between the p-n type and n-n TiO2‑x-c-Si heterojunction types were examined and the electron transport selectivity of TiO2‑x was revealed.

CSI: Dognapping workshop : an outreach experiment designed to produce students that are hooked on science.

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

Boyle, Timothy J.; Gorman, Anna K.; Pratt, Harry D., III

The CSI: Dognapping Workshop is a culmination of the more than 65 Sandian staff and intern volunteers dedication to exciting and encouraging the next generation of scientific leaders. This 2 hour workshop used a 'theatrical play' and 'hands on' activities that was fun, exciting and challenging for 3rd-5th graders while meeting science curriculum standards. In addition, new pedagogical methods were developed in order to introduce nanotechnology to the public. Survey analysis indicated that the workshop had an overall improvement and positive impact on helping the students to understand concepts from materials science and chemistry as well as increased our interactionmore » with the K-5 community. Anecdotal analyses showed that this simple exercise will have far reaching impact with the results necessary to maintain the United States as the scientific leader in the world. This experience led to the initiation of over 100 Official Junior Scientists.« less

Development and experimental validation of downlink multiuser MIMO-OFDM in gigabit wireless LAN systems

NASA Astrophysics Data System (ADS)

Ishihara, Koichi; Asai, Yusuke; Kudo, Riichi; Ichikawa, Takeo; Takatori, Yasushi; Mizoguchi, Masato

2013-12-01

Multiuser multiple-input multiple-output (MU-MIMO) has been proposed as a means to improve spectrum efficiency for various future wireless communication systems. This paper reports indoor experimental results obtained for a newly developed and implemented downlink (DL) MU-MIMO orthogonal frequency division multiplexing (OFDM) transceiver for gigabit wireless local area network systems in the microwave band. In the transceiver, the channel state information (CSI) is estimated at each user and fed back to an access point (AP) on a real-time basis. At the AP, the estimated CSI is used to calculate the transmit beamforming weight for DL MU-MIMO transmission. This paper also proposes a recursive inverse matrix computation scheme for computing the transmit weight in real time. Experiments with the developed transceiver demonstrate its feasibility in a number of indoor scenarios. The experimental results clarify that DL MU-MIMO-OFDM transmission can achieve a 972-Mbit/s transmission data rate with simple digital signal processing of single-antenna users in an indoor environment.

Conserved Kv4 N-terminal domain critical for effects of Kv channel-interacting protein 2.2 on channel expression and gating.

PubMed

Bähring, R; Dannenberg, J; Peters, H C; Leicher, T; Pongs, O; Isbrandt, D

2001-06-29

Association of Kv channel-interacting proteins (KChIPs) with Kv4 channels leads to modulation of these A-type potassium channels (An, W. F., Bowlby, M. R., Betty, M., Cao, J., Ling, H. P., Mendoza, G., Hinson, J. W., Mattsson, K. I., Strassle, B. W., Trimmer, J. S., and Rhodes, K. J. (2000) Nature 403, 553-556). We cloned a KChIP2 splice variant (KChIP2.2) from human ventricle. In comparison with KChIP2.1, coexpression of KChIP2.2 with human Kv4 channels in mammalian cells slowed the onset of Kv4 current inactivation (2-3-fold), accelerated the recovery from inactivation (5-7-fold), and shifted Kv4 steady-state inactivation curves by 8-29 mV to more positive potentials. The features of Kv4.2/KChIP2.2 currents closely resemble those of cardiac rapidly inactivating transient outward currents. KChIP2.2 stimulated the Kv4 current density in Chinese hamster ovary cells by approximately 55-fold. This correlated with a redistribution of immunoreactivity from perinuclear areas to the plasma membrane. Increased Kv4 cell-surface expression and current density were also obtained in the absence of KChIP2.2 when the highly conserved proximal Kv4 N terminus was deleted. The same domain is required for association of KChIP2.2 with Kv4 alpha-subunits. We propose that an efficient transport of Kv4 channels to the cell surface depends on KChIP binding to the Kv4 N-terminal domain. Our data suggest that the binding is necessary, but not sufficient, for the functional activity of KChIPs.

Ventromedial medulla inhibitory neuron inactivation induces REM sleep without atonia and REM sleep behavior disorder.

PubMed

Valencia Garcia, Sara; Brischoux, Frédéric; Clément, Olivier; Libourel, Paul-Antoine; Arthaud, Sébastien; Lazarus, Michael; Luppi, Pierre-Hervé; Fort, Patrice

2018-02-05

Despite decades of research, there is a persistent debate regarding the localization of GABA/glycine neurons responsible for hyperpolarizing somatic motoneurons during paradoxical (or REM) sleep (PS), resulting in the loss of muscle tone during this sleep state. Combining complementary neuroanatomical approaches in rats, we first show that these inhibitory neurons are localized within the ventromedial medulla (vmM) rather than within the spinal cord. We then demonstrate their functional role in PS expression through local injections of adeno-associated virus carrying specific short-hairpin RNA in order to chronically impair inhibitory neurotransmission from vmM. After such selective genetic inactivation, rats display PS without atonia associated with abnormal and violent motor activity, concomitant with a small reduction of daily PS quantity. These symptoms closely mimic human REM sleep behavior disorder (RBD), a prodromal parasomnia of synucleinopathies. Our findings demonstrate the crucial role of GABA/glycine inhibitory vmM neurons in muscle atonia during PS and highlight a candidate brain region that can be susceptible to α-synuclein-dependent degeneration in RBD patients.

Multiple Frequency Contrast Source Inversion Method for Vertical Electromagnetic Profiling: 2D Simulation Results and Analyses

NASA Astrophysics Data System (ADS)

Li, Jinghe; Song, Linping; Liu, Qing Huo

2016-02-01

A simultaneous multiple frequency contrast source inversion (CSI) method is applied to reconstructing hydrocarbon reservoir targets in a complex multilayered medium in two dimensions. It simulates the effects of a salt dome sedimentary formation in the context of reservoir monitoring. In this method, the stabilized biconjugate-gradient fast Fourier transform (BCGS-FFT) algorithm is applied as a fast solver for the 2D volume integral equation for the forward computation. The inversion technique with CSI combines the efficient FFT algorithm to speed up the matrix-vector multiplication and the stable convergence of the simultaneous multiple frequency CSI in the iteration process. As a result, this method is capable of making quantitative conductivity image reconstruction effectively for large-scale electromagnetic oil exploration problems, including the vertical electromagnetic profiling (VEP) survey investigated here. A number of numerical examples have been demonstrated to validate the effectiveness and capacity of the simultaneous multiple frequency CSI method for a limited array view in VEP.

Development and Pilot of the Caregiver Strategies Inventory.

PubMed

Kirby, Anne V; Little, Lauren M; Schultz, Beth; Watson, Linda R; Zhang, Wanqing; Baranek, Grace T

2016-01-01

Children with autism spectrum disorder often demonstrate unusual behavioral responses to sensory stimuli (i.e., sensory features). To manage everyday activities, caregivers may implement strategies to address these features during family routines. However, investigation of specific strategies used by caregivers is limited by the lack of empirically developed measures. In this study, we describe the development and pilot results of the Caregiver Strategies Inventory (CSI), a supplement to the Sensory Experiences Questionnaire Version 3.0 (SEQ 3.0; Baranek, 2009) that measures caregivers' strategies in response to their children's sensory features. Three conceptually derived and empirically grounded strategy types were tested: cognitive-behavioral, sensory-perceptual, and avoidance. Results indicated that the CSI demonstrated good internal consistency and that strategy use was related to child age and cognition. Moreover, parent feedback after completing the CSI supported its utility and social validity. The CSI may be used alongside the SEQ 3.0 to facilitate a family-centered approach to assessment and intervention planning. Copyright © 2016 by the American Occupational Therapy Association, Inc.

Low Cost, High Performance Avalanche Photodiodes for Enabling High Sensitivity Bio-fluorescence Detection (First Year of a Two-year Program)

DTIC Science & Technology

2011-04-01

nGaNGaNSiCSiC EE   4 When the electric field can punch through into the GaN absorption region, as illustrated in the band diagram in figure 2 (left...cr SiCSiC br GaNGaN EE EE0       SiC b SiC GaN d VE E 0 q(Vbi-Vb) GaN SiC n dSiC dGaN EGaN ESiC q(Vbi-Vb) GaN ndSiC...detector (figure 2, right). cr SiCSiCn br GaNGaN cr SiCSiC EEE   0 20 40 60 80 100 120 140 160 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 EGaN El ec

Approaching total absorption of graphene strips using a c-Si subwavelength periodic membrane

NASA Astrophysics Data System (ADS)

Sang, Tian; Wang, Rui; Li, Junlang; Zhou, Jianyu; Wang, Yueke

2018-04-01

Approaching total absorption of graphene strips at near infrared using a crystalline-silicon (c-Si) subwavelength periodic membrane (SPM) is presented. The absorption in graphene strips in a c-Si SPM is enhanced by a resonant tip, which is resulted from the coupling between the guided mode and the radiation mode through symmetry breaking of the structure at near-normal incidence. The enhancement of the electric field intensity is increased 1939 times and the group velocity of light is decreased to 3.55 ×10-4c at resonance, and 99.3% absorption in graphene strips can be achieved by critical coupling at the incident angle of 2°. High absorption of the graphene strips can be maintained as the etching thickness, the strip width, and the period are altered. When this type of c-Si SPM with graphene strips is used in refractive index sensors, it shows excellent sensing properties due to its stable near-unity absorption.

Automotive assessment of carbon-silicon composite anodes and methods of fabrication

NASA Astrophysics Data System (ADS)

Karulkar, Mohan; Blaser, Rachel; Kudla, Bob

2015-01-01

To assess the potential of carbon silicon composite anodes for automotive applications, C-Si anodes were fabricated and certain improvements employed. The use of a PVDF buffer layer is demonstrated for the first time with a C-Si composite material. The buffer layer increases adhesion by 89%, and increases capacity by 50-80%. Also, a limited capacity range is employed to improve cycle life by up to 200%, and enable currents as high as 2 mA cm-1. The combined use of a buffer layer and limited capacity range has not been reported before. A model is also presented for comparing C-Si performance with real-world automotive targets from USABC, including energy density, power density, specific energy, and specific power. The analysis reveals a capacity penalty that arises from pairing C-Si with a traditional cathode (NCA), and which prevents the cell from meeting all targets. Scenarios are presented in which a higher-capacity cathode (250 mAh g-1) allows all targets to be hypothetically met.

A multicenter randomised, 1-year comparative effectiveness, parallel-group trial protocol of a physical therapy approach compared to corticosteroid injection on pain and function related to knee osteoarthritis (PTA Trial)

PubMed

Deyle, Gail D; Gill, Norman W; Rhon, Daniel I; Allen, Chris S; Allison, Stephen C; Hando, Ben R; Petersen, Evan J; Dusenberry, Douglas I; Bellamy, Nicholas

2016-03-31

Corticosteroid injections (CSIs) are commonly used as an initial or a primary intervention for knee osteoarthritis (OA). Consistent evidence indicates CSIs offer symptom relief with conflicting reports regarding long-term efficacy. Physical therapy (PT) offers a non-invasive alternative. There is moderate evidence suggesting short-term and long-term symptom relief and functional improvement with PT interventions. Patients with knee OA are more commonly prescribed CSI than PT prior to total joint replacement. UnitedHealthcare and Military Health System data show substantially more total knee replacement patients receive preoperative CSI than PT. There are no studies comparing CSI to a PT approach in individuals with knee OA. The primary objective of this study is to compare the effectiveness of CSI to PT in individuals with knee OA at 1, 2 and 12 months. We plan to recruit 156 participants meeting established knee OA criteria. Following informed consent, participants will be randomised to receive either CSI or PT. All participants will receive instruction on recommended exercise and weight control strategies plus usual medical care. The CSI intervention consisting of 3 injections and the PT intervention consisting of 8-12 sessions will be spaced over 12 months. Measures of the dependent variables (DVs) will occur at baseline, 4 weeks, 8 weeks, 6 months and 12 months post enrolment. This pragmatic, randomised clinical trial will be a mixed-model 2×5 factorial design. The independent variables are treatment (CSI and PT) and time with five levels from baseline to 1 year. The primary DV is the Western Ontario & McMaster Universities Arthritis Index (WOMAC). We will also compare healthcare utilisation between the 2 groups. The protocol was approved by the Madigan Army Medical Center Institutional Review Board. The authors intend to publish the results in a peer-reviewed source. NCT01427153. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Active vibration control activities at the LaRC - Present and future

NASA Technical Reports Server (NTRS)

Newsom, J. R.

1990-01-01

The NASA Controls-Structures-Interaction (CSI) program is presented with a description of the ground testing element objectives and approach. The goal of the CSI program is to develop and validate the technology required to design, verify and operate space systems in which the structure and the controls interact beneficially to meet the needs of future NASA missions. The operational Mini-Mast ground testbed and some sample active vibration control experimental results are discussed along with a description of the CSI Evolutionary Model testbed presently under development. Initial results indicate that embedded sensors and actuators are effective in controlling a large truss/reflector structure.

Electronic communication in phosphine substituted bridged dirhenium complexes - clarifying ambiguities raised by the redox non-innocence of the C4H2- and C4-bridges.

PubMed

Li, Yan; Blacque, Olivier; Fox, Thomas; Luber, Sandra; Polit, Walther; Winter, Rainer F; Venkatesan, Koushik; Berke, Heinz

2016-04-07

The mononuclear rhenium carbyne complex trans-[Re(C[triple bond, length as m-dash]CSiMe3)([triple bond, length as m-dash]C-Me)(PMe3)4][PF6] (2) was prepared in 90% yield by heating a mixture of the dinitrogen complex trans-[ReCl(N2)(PMe3)4] (1), TlPF6, and an excess of HC[triple bond, length as m-dash]CSiMe3. 2 could be deprotonated with KOtBu to the vinylidene complex trans-[Re(C[triple bond, length as m-dash]CSiMe3)([double bond, length as m-dash]C[double bond, length as m-dash]CH2)(PMe3)4] (3) in 98% yield. Oxidation of 3 with 1.2 equiv. of [Cp2Fe][PF6] at -78 °C gave the Cβ-C'β coupled dinuclear rhenium biscarbyne complex trans-[(Me3SiC[triple bond, length as m-dash]C)(PMe3)4Re[triple bond, length as m-dash]C-CH2-CH2-C[triple bond, length as m-dash]Re(PMe3)4(C[triple bond, length as m-dash]CSiMe3)][PF6]2 (5) in 92% yield. Deprotonation of 5 with an excess of KOtBu in THF produced the diamagnetic trans-[(Me3SiC[triple bond, length as m-dash]C)(PMe3)4Re[double bond, length as m-dash]C[double bond, length as m-dash]CH-CH[double bond, length as m-dash]C[double bond, length as m-dash]Re(PMe3)4(C[triple bond, length as m-dash]CSiMe3)] complex (E-6(S)) in 87% yield with an E-butadienediylidene bridge. Density functional theory (DFT) calculations of E-6(S) confirmed its singlet ground state. The Z-form of 6 (Z-6(S)) could not be observed, which is in accord with its DFT calculated 17.8 kJ mol(-1) higher energy. Oxidation of E-6 with 2 equiv. of [Cp2Fe][PF6] resulted in the stable diamagnetic dicationic trans-[(Me3SiC[triple bond, length as m-dash]C)(PMe3)4Re[triple bond, length as m-dash]C-CH[double bond, length as m-dash]CH-C[triple bond, length as m-dash]Re(PMe3)4(C[triple bond, length as m-dash]CSiMe3)][PF6]2 complex (E-6[PF6]2) with an ethylenylidene dicarbyne structure of the bridge. The paramagnetic mixed-valence (MV) complex E-6[PF6] was obtained by comproportionation of E-6(S) and E-6[PF6]2 or by oxidation of E-6(S) with 1 equiv. of [Cp2Fe][PF6]. The dicationic trans-[(Me3SiC[triple bond, length as m-dash]C)(PMe3)4Re[triple bond, length as m-dash]C-C[triple bond, length as m-dash]C-C[triple bond, length as m-dash]Re(PMe3)4(C[triple bond, length as m-dash]CSiMe3)][PF6]2 (7[PF6]2) complex, attributed a butynedi(triyl) bridge structure, was obtained by deprotonation of E-6[PF6]2 with KOtBu followed by oxidation with 2 equiv. of [Cp2Fe][PF6]. The neutral complex 7 could be accessed best by reduction of 7[PF6]2 with KH in the presence of 18-crown-6. According to DFT calculations 7 possesses two equilibrating electronic states: diamagnetic 7(S) and triplet 7(F) with ferromagnetically coupled spins. The latter is calculated to be 5.2 kcal mol(-1) lower in energy than 7(S). There is experimental evidence that 7(S) prevails in solution. 7 could not be isolated in the crystalline state and is unstable transforming mainly by H-abstraction to give E-6(S). UV-Vis-NIR spectroscopy for the dinuclear rhenium complexes E-6(S), E-6[PF6] and E-6[PF6]2, as well as EPR spectroscopic and variable-temperature magnetization measurements for the MV complex E-6[PF6] were also conducted. Spectro-electrochemical reduction studies on 7[PF6]2 allowed the characterization of the mono- and direduced forms of 7(+) and 7 by means of IR- and UV-Vis-NIR-spectroscopy and revealed the chemical fate of the higher reduced form.

Reliability and Accuracy of Static Parameters Obtained From Ink and Pressure Platform Footprints.

PubMed

Zuil-Escobar, Juan Carlos; Martínez-Cepa, Carmen Belén; Martín-Urrialde, Jose Antonio; Gómez-Conesa, Antonia

2016-09-01

The purpose of this study was to evaluate the accuracy and the intrarater reliability of arch angle (AA), Staheli Index (SI), and Chippaux-Smirak Index (CSI) obtained from ink and pressure platform footprints. We obtained AA, SI, and CSI measurements from ink pedigraph footprints and pressure platform footprints in 40 healthy participants (aged 25.65 ± 5.187 years). Intrarater reliability was calculated for all parameters obtained using the 2 methods. Standard error of measurement and minimal detectable change were also calculated. A repeated-measure analysis of variance was used to identify differences between ink and pressure platform footprints. Intraclass correlation coefficient and Bland and Altman plots were used to assess similar parameters obtained using different methods. Intrarater reliability was >0.9 for all parameters and was slightly higher for the ink footprints. No statistical difference was reported in repeated-measure analysis of variance for any of the parameters. Intraclass correlation coefficient values from AA, SI, and CSI that were obtained using ink footprints and pressure platform footprints were excellent, ranging from 0.797 to 0.829. However, pressure platform overestimated AA and underestimated SI and CSI. Our study revealed that AA, SI, and CSI were similar regardless of whether the ink or pressure platform method was used. In addition, the parameters indicated high intrarater reliability and were reproducible. Copyright © 2016. Published by Elsevier Inc.

Dynamic metabolic imaging of hyperpolarized [2-(13) C]pyruvate using spiral chemical shift imaging with alternating spectral band excitation.

PubMed

Josan, Sonal; Hurd, Ralph; Park, Jae Mo; Yen, Yi-Fen; Watkins, Ron; Pfefferbaum, Adolf; Spielman, Daniel; Mayer, Dirk

2014-06-01

In contrast to [1-(13) C]pyruvate, hyperpolarized [2-(13) C]pyruvate permits the ability to follow the (13) C label beyond flux through pyruvate dehydrogenase complex and investigate the incorporation of acetyl-coenzyme A into different metabolic pathways. However, chemical shift imaging (CSI) with [2-(13) C]pyruvate is challenging owing to the large spectral dispersion of the resonances, which also leads to severe chemical shift displacement artifacts for slice-selective acquisitions. This study introduces a sequence for three-dimensional CSI of [2-(13) C]pyruvate using spectrally selective excitation of limited frequency bands containing a subset of metabolites. Dynamic CSI data were acquired alternately from multiple frequency bands in phantoms for sequence testing and in vivo in rat heart. Phantom experiments verified the radiofrequency pulse design and demonstrated that the signal behavior of each group of resonances was unaffected by excitation of the other frequency bands. Dynamic three-dimensional (13) C CSI data demonstrated the sequence capability to image pyruvate, lactate, acetylcarnitine, glutamate, and acetoacetate, enabling the analysis of organ-specific spectra and metabolite time courses. The presented method allows CSI of widely separated resonances without chemical shift displacement artifact, acquiring multiple frequency bands alternately to obtain dynamic time-course information. This approach enables robust imaging of downstream metabolic products of acetyl-coenzyme A with hyperpolarized [2-(13) C]pyruvate. Copyright © 2013 Wiley Periodicals, Inc.

Immobilized nickel hexacyanoferrate on activated carbons for efficient attenuation of radio toxic Cs(I) from aqueous solutions

NASA Astrophysics Data System (ADS)

Lalhmunsiama; Lalhriatpuia, C.; Tiwari, Diwakar; Lee, Seung-Mok

2014-12-01

The aim of this study is to immobilize nickel hexacyanoferrate onto the large surface of activated carbons (ACs) precursor to rice hulls and areca nut waste materials. These nickel hexacyanoferrate immobilized materials are then assessed in the effective attenuation of radio logically important cesium ions from aqueous solutions. The solid samples are characterized by the XRD analytical method and surface morphology is obtained from the SEM images. The batch reactor experiments show that an increase in sorptive pH (2.0-10.0) apparently not affecting the high percent uptake of Cs(I). Equilibrium modeling studies suggest that the data are reasonably and relatively fitted well to the Langmuir adsorption isotherm. Kinetic studies show that sorption process is fairly rapid and the kinetic data are fitted well to the pseudo-second order rate model. Increasing the background electrolyte concentration from 0.001 to 0.1 mol/L NaCl causes insignificant decrease in Cs(I) removal which infers the higher selectivity of these materials for Cs(I) from aqueous solutions. Further, the column reactor operations enable to obtain the breakthrough data which are then fitted to the Thomas non-linear equation as to obtain the loading capacity of column for Cs(I). The results show that the modified materials show potential applicability in the attenuation of radio toxic cesium from aqueous solution.

Micro-precision control/structure interaction technology for large optical space systems

NASA Technical Reports Server (NTRS)

Sirlin, Samuel W.; Laskin, Robert A.

1993-01-01

The CSI program at JPL is chartered to develop the structures and control technology needed for sub-micron level stabilization of future optical space systems. The extreme dimensional stability required for such systems derives from the need to maintain the alignment and figure of critical optical elements to a small fraction (typically 1/20th to 1/50th) of the wavelength of detected radiation. The wavelength is about 0.5 micron for visible light and 0.1 micron for ultra-violet light. This lambda/50 requirement is common to a broad class of optical systems including filled aperture telescopes (with monolithic or segmented primary mirrors), sparse aperture telescopes, and optical interferometers. The challenge for CSI arises when such systems become large, with spatially distributed optical elements mounted on a lightweight, flexible structure. In order to better understand the requirements for micro-precision CSI technology, a representative future optical system was identified and developed as an analytical testbed for CSI concepts and approaches. An optical interferometer was selected as a stressing example of the relevant mission class. The system that emerged was termed the Focus Mission Interferometer (FMI). This paper will describe the multi-layer control architecture used to address the FMI's nanometer level stabilization requirements. In addition the paper will discuss on-going and planned experimental work aimed at demonstrating that multi-layer CSI can work in practice in the relevant performance regime.

Inactivation gating of Kv7.1 channels does not involve concerted cooperative subunit interactions.

PubMed

Meisel, Eshcar; Tobelaim, William; Dvir, Meidan; Haitin, Yoni; Peretz, Asher; Attali, Bernard

2018-01-01

Inactivation is an intrinsic property of numerous voltage-gated K + (Kv) channels and can occur by N-type or/and C-type mechanisms. N-type inactivation is a fast, voltage independent process, coupled to activation, with each inactivation particle of a tetrameric channel acting independently. In N-type inactivation, a single inactivation particle is necessary and sufficient to occlude the pore. C-type inactivation is a slower process, involving the outermost region of the pore and is mediated by a concerted, highly cooperative interaction between all four subunits. Inactivation of Kv7.1 channels does not exhibit the hallmarks of N- and C-type inactivation. Inactivation of WT Kv7.1 channels can be revealed by hooked tail currents that reflects the recovery from a fast and voltage-independent inactivation process. However, several Kv7.1 mutants such as the pore mutant L273F generate an additional voltage-dependent slow inactivation. The subunit interactions during this slow inactivation gating remain unexplored. The goal of the present study was to study the nature of subunit interactions along Kv7.1 inactivation gating, using concatenated tetrameric Kv7.1 channel and introducing sequentially into each of the four subunits the slow inactivating pore mutation L273F. Incorporating an incremental number of inactivating mutant subunits did not affect the inactivation kinetics but slowed down the recovery kinetics from inactivation. Results indicate that Kv7.1 inactivation gating is not compatible with a concerted cooperative process. Instead, adding an inactivating subunit L273F into the Kv7.1 tetramer incrementally stabilizes the inactivated state, which suggests that like for activation gating, Kv7.1 slow inactivation gating is not a concerted process.

A Conducting State with Properties of a Slow Inactivated State in a Shaker K+ Channel Mutant

PubMed Central

Olcese, Riccardo; Sigg, Daniel; Latorre, Ramon; Bezanilla, Francisco; Stefani, Enrico

2001-01-01

In Shaker K+ channel, the amino terminus deletion Δ6-46 removes fast inactivation (N-type) unmasking a slow inactivation process. In Shaker Δ6-46 (Sh-IR) background, two additional mutations (T449V-I470C) remove slow inactivation, producing a noninactivating channel. However, despite the fact that Sh-IR-T449V-I470C mutant channels remain conductive, prolonged depolarizations (1 min, 0 mV) produce a shift of the QV curve by about −30 mV, suggesting that the channels still undergo the conformational changes typical of slow inactivation. For depolarizations longer than 50 ms, the tail currents measured during repolarization to −90 mV display a slow component that increases in amplitude as the duration of the depolarizing pulse increases. We found that the slow development of the QV shift had a counterpart in the amplitude of the slow component of the ionic tail current that is not present in Sh-IR. During long depolarizations, the time course of both the increase in the slow component of the tail current and the change in voltage dependence of the charge movement could be well fitted by exponential functions with identical time constant of 459 ms. Single channel recordings revealed that after prolonged depolarizations, the channels remain conductive for long periods after membrane repolarization. Nonstationary autocovariance analysis performed on macroscopic current in the T449V-I470C mutant confirmed that a novel open state appears with increasing prepulse depolarization time. These observations suggest that in the mutant studied, a new open state becomes progressively populated during long depolarizations (>50 ms). An appealing interpretation of these results is that the new open state of the mutant channel corresponds to a slow inactivated state of Sh-IR that became conductive. PMID:11158167

The "CSI" Effect: Changing the Face of Science

ERIC Educational Resources Information Center

Jones, Richard; Bangert, Arthur

2006-01-01

The authors suggest that "CSI," a public mass media product, and other television programming have greatly influenced how students, especially female students, perceive scientists at work. Perhaps the increased airing of television programs focusing on laboratory sciences has caused student perceptions of scientists to shift away from the "mad…

Slow Inactivation in Shaker K Channels Is Delayed by Intracellular Tetraethylammonium

PubMed Central

González-Pérez, Vivian; Neely, Alan; Tapia, Christian; González-Gutiérrez, Giovanni; Contreras, Gustavo; Orio, Patricio; Lagos, Verónica; Rojas, Guillermo; Estévez, Tania; Stack, Katherine; Naranjo, David

2008-01-01

After removal of the fast N-type inactivation gate, voltage-sensitive Shaker (Shaker IR) K channels are still able to inactivate, albeit slowly, upon sustained depolarization. The classical mechanism proposed for the slow inactivation observed in cell-free membrane patches—the so called C inactivation—is a constriction of the external mouth of the channel pore that prevents K+ ion conduction. This constriction is antagonized by the external application of the pore blocker tetraethylammonium (TEA). In contrast to C inactivation, here we show that, when recorded in whole Xenopus oocytes, slow inactivation kinetics in Shaker IR K channels is poorly dependent on external TEA but severely delayed by internal TEA. Based on the antagonism with internally or externally added TEA, we used a two-pulse protocol to show that half of the channels inactivate by way of a gate sensitive to internal TEA. Such gate had a recovery time course in the tens of milliseconds range when the interpulse voltage was −90 mV, whereas C-inactivated channels took several seconds to recover. Internal TEA also reduced gating charge conversion associated to slow inactivation, suggesting that the closing of the internal TEA-sensitive inactivation gate could be associated with a significant amount of charge exchange of this type. We interpreted our data assuming that binding of internal TEA antagonized with U-type inactivation (Klemic, K.G., G.E. Kirsch, and S.W. Jones. 2001. Biophys. J. 81:814–826). Our results are consistent with a direct steric interference of internal TEA with an internally located slow inactivation gate as a “foot in the door” mechanism, implying a significant functional overlap between the gate of the internal TEA-sensitive slow inactivation and the primary activation gate. But, because U-type inactivation is reduced by channel opening, trapping the channel in the open conformation by TEA would also yield to an allosteric delay of slow inactivation. These results provide a framework to explain why constitutively C-inactivated channels exhibit gating charge conversion, and why mutations at the internal exit of the pore, such as those associated to episodic ataxia type I in hKv1.1, cause severe changes in inactivation kinetics. PMID:19029372

Inactivation of Norovirus on Dry Copper Alloy Surfaces

PubMed Central

Warnes, Sarah L.; Keevil, C. William

2013-01-01

Noroviruses (family Caliciviridae) are the primary cause of viral gastroenteritis worldwide. The virus is highly infectious and touching contaminated surfaces can contribute to infection spread. Although the virus was identified over 40 years ago the lack of methods to assess infectivity has hampered the study of the human pathogen. Recently the murine virus, MNV-1, has successfully been used as a close surrogate. Copper alloys have previously been shown to be effective antimicrobial surfaces against a range of bacteria and fungi. We now report rapid inactivation of murine norovirus on alloys, containing over 60% copper, at room temperature but no reduction of infectivity on stainless steel dry surfaces in simulated wet fomite and dry touch contamination. The rate of inactivation was initially very rapid and proportional to copper content of alloy tested. Viral inactivation was not as rapid on brass as previously observed for bacteria but copper-nickel alloy was very effective. The use of chelators and quenchers of reactive oxygen species (ROS) determined that Cu(II) and especially Cu(I) ions are still the primary effectors of toxicity but quenching superoxide and hydroxyl radicals did not confer protection. This suggests Fenton generation of ROS is not important for the inactivation mechanism. One of the targets of copper toxicity was the viral genome and a reduced copy number of the gene for a viral encoded protein, VPg (viral-protein-genome-linked), which is essential for infectivity, was observed following contact with copper and brass dry surfaces. The use of antimicrobial surfaces containing copper in high risk closed environments such as cruise ships and care facilities could help to reduce the spread of this highly infectious and costly pathogen. PMID:24040380

Monitoring of atopic dermatitis using leaky coaxial cable.

PubMed

Dong, Binbin; Ren, Aifeng; Shah, Syed Aziz; Hu, Fangming; Zhao, Nan; Yang, Xiaodong; Haider, Daniyal; Zhang, Zhiya; Zhao, Wei; Abbasi, Qammer Hussain

2017-12-01

In our daily life, inadvertent scratching may increase the severity of skin diseases (such as atopic dermatitis etc.). However, people rarely pay attention to this matter, so the known measurement behaviour of the movement is also very little. Nevertheless, the behaviour and frequency of scratching represent the degree of itching, and the analysis of scratching frequency is helpful to the doctor's clinical dosage. In this Letter, a novel system is proposed to monitor the scratching motion of a sleeping human body at night. The core device of the system is just a leaky coaxial cable (LCX) and a router. Commonly, LCX is used in the blind field or semi-blindfield in wireless communication. The new idea is that the leaky cable is placed on the bed, and then the state information of physical layer of wireless communication channels is acquired to identify the scratching motion and other small body movements in the human sleep process. The results show that it can be used to detect the movement and its duration. Channel state information (CSI) packet is collected by card installed in the computer based on the 802.11n protocol. The characterisation of the scratch motion in the collected CSI is unique, so it can be distinguished from the wireless channel amplitude variation trend.

Monitoring of atopic dermatitis using leaky coaxial cable

PubMed Central

Dong, Binbin; Ren, Aifeng; Shah, Syed Aziz; Hu, Fangming; Zhao, Nan; Haider, Daniyal; Zhang, Zhiya; Zhao, Wei; Abbasi, Qammer Hussain

2017-01-01

In our daily life, inadvertent scratching may increase the severity of skin diseases (such as atopic dermatitis etc.). However, people rarely pay attention to this matter, so the known measurement behaviour of the movement is also very little. Nevertheless, the behaviour and frequency of scratching represent the degree of itching, and the analysis of scratching frequency is helpful to the doctor's clinical dosage. In this Letter, a novel system is proposed to monitor the scratching motion of a sleeping human body at night. The core device of the system is just a leaky coaxial cable (LCX) and a router. Commonly, LCX is used in the blind field or semi-blindfield in wireless communication. The new idea is that the leaky cable is placed on the bed, and then the state information of physical layer of wireless communication channels is acquired to identify the scratching motion and other small body movements in the human sleep process. The results show that it can be used to detect the movement and its duration. Channel state information (CSI) packet is collected by card installed in the computer based on the 802.11n protocol. The characterisation of the scratch motion in the collected CSI is unique, so it can be distinguished from the wireless channel amplitude variation trend. PMID:29383259

Absence of ion-binding affinity in the putatively inactivated low-[K+] structure of the KcsA potassium channel.

PubMed

Boiteux, Céline; Bernèche, Simon

2011-01-12

Potassium channels are membrane proteins that selectively conduct K(+) across cellular membranes. The narrowest part of their pore, the selectivity filter, is responsible for distinguishing K(+) from Na(+), and can also act as a gate through a mechanism known as C-type inactivation. It has been proposed that a conformation of the KcsA channel obtained by crystallization in presence of low concentration of K(+) (PDB 1K4D) could correspond to the C-type inactivated state. Here, we show using molecular mechanics simulations that such conformation has little ion-binding affinity and that ions do not contribute to its stability. The simulations suggest that, in this conformation, the selectivity filter is mostly occupied by water molecules. Whether such ion-free state of the KcsA channel is physiologically accessible and representative of the inactivated state of eukaryotic channels remains unclear. Copyright © 2011 Elsevier Ltd. All rights reserved.

Effect of Clustering Algorithm on Establishing Markov State Model for Molecular Dynamics Simulations.

PubMed

Li, Yan; Dong, Zigang

2016-06-27

Recently, the Markov state model has been applied for kinetic analysis of molecular dynamics simulations. However, discretization of the conformational space remains a primary challenge in model building, and it is not clear how the space decomposition by distinct clustering strategies exerts influence on the model output. In this work, different clustering algorithms are employed to partition the conformational space sampled in opening and closing of fatty acid binding protein 4 as well as inactivation and activation of the epidermal growth factor receptor. Various classifications are achieved, and Markov models are set up accordingly. On the basis of the models, the total net flux and transition rate are calculated between two distinct states. Our results indicate that geometric and kinetic clustering perform equally well. The construction and outcome of Markov models are heavily dependent on the data traits. Compared to other methods, a combination of Bayesian and hierarchical clustering is feasible in identification of metastable states.

An analysis of the sectorial influence of CSI300 stocks within the directed network

NASA Astrophysics Data System (ADS)

Mai, Yong; Chen, Huan; Meng, Lei

2014-02-01

This paper uses the Partial Correlation Planar maximally filtered Graph (PCPG) method to construct a directed network for the constituent stocks underlying the China Securities Index 300 (CSI300). We also analyse the impact of individual stocks. We find that the CSI300 market is a scale-free network with a relatively small power law exponent. The volatility of the stock prices has significant impact on other stocks. In the sectorial network, the industrial sector is the most influential one over other sectors, the financial sector only has a modest influence, while the telecommunication services sector’s influence is marginal. In addition, such inter-sector influence displays quarterly stability.

Function of the centromedial amygdala in reward devaluation and open-field activity.

PubMed

Kawasaki, K; Glueck, A C; Annicchiarico, I; Papini, M R

2015-09-10

The present research aimed at determining the role played by the amygdala in reward devaluation using transient inactivation induced by lidocaine microinfusions into the centromedial region. Two situations involving reward devaluation were tested in rats: consummatory successive negative contrast (cSNC) and anticipatory negative contrast (ANC). In cSNC, rats exposed to a downshift from 32% to 4% sucrose consume less 4% sucrose than rats always exposed to 4% sucrose. Extensive evidence suggests that reward devaluation in the cSNC situation is accompanied by negative emotion. In ANC, rats consume less 4% sucrose when each session is closely followed by access to 32% sucrose rather than by 4% sucrose. Evidence suggests that reward devaluation in the ANC situation does not involve negative emotions; rather, ANC appears to involve Pavlovian anticipation of the higher value solution. To test the effects of lidocaine microinfusions in a situation known to induce negative emotion, but unrelated to reward devaluation, animals were also exposed to a lighted open field. Centromedial amygdala inactivation reduced the cSNC effect and increased exploratory behavior in the open field, both effects consistent with a reduction in negative emotional state. However, no detectable effects of amygdala inactivation were observed in the ANC situation. These results suggest that, first, the function of the amygdala is not unique to reward devaluation and, second, it is concerned with tagging the devaluation experience with aversive valence. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

The CSI Schools Project

ERIC Educational Resources Information Center

Dorling, Mark; Johnstone, Emm

2012-01-01

The popularity of forensic science in schools continues to grow alongside the proportion of prime time scheduling devoted to CSI television shows. Yet the understanding of how forensic tests are used in narrowing down a field of possible suspects to the point where just one can be arrested or taken to trial is far less well understood. Students…

75 FR 70057 - Self-Regulatory Organizations; EDGA Exchange, Inc.; Notice of Filing and Immediate Effectiveness...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-16

..., and deals with U.S. securities laws, regulations, sales practices and special products drawn from the standard Series 7 examination. The Series 37 version is for Canadian registrants who have successfully completed the basic core module of the CSI Global Education (``CSI'', formerly the Canadian Securities...

75 FR 70052 - Self-Regulatory Organizations; EDGX Exchange, Inc.; Notice of Filing and Immediate Effectiveness...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-16

..., and deals with U.S. securities laws, regulations, sales practices and special products drawn from the standard Series 7 examination. The Series 37 version is for Canadian registrants who have successfully completed the basic core module of the CSI Global Education (``CSI'', formerly the Canadian Securities...

78 FR 41911 - Foreign-Trade Zone 39-Dallas-Fort Worth, Texas; CSI Calendering, Inc. (Rubber Coated Textile...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-12

... DEPARTMENT OF COMMERCE Foreign-Trade Zones Board [B-25-2013] Foreign-Trade Zone 39--Dallas-Fort Worth, Texas; CSI Calendering, Inc. (Rubber Coated Textile Fabric); Arlington, Texas On March 4, 2013, the Dallas/Fort Worth International Airport Board, grantee of FTZ 39, submitted a notification of...

Chi Sigma Iota Chapter Leadership and Professional Identity Development in Early Career Counselors

ERIC Educational Resources Information Center

Luke, Melissa; Goodrich, Kristopher M.

2010-01-01

As the academic and professional honor society of counseling, Chi Sigma Iota (CSI) has been recognized in developing advocacy, leadership, and professional identity in student and professional members. A qualitative, grounded theory study was conducted to investigate experiences of 15 early career counselors who were CSI chapter leaders as…

Removal of sodium inactivation and block of sodium channels by chloramine-T in crayfish and squid giant axons.

PubMed Central

Huang, J. M.; Tanguy, J.; Yeh, J. Z.

1987-01-01

Modification of sodium channels by chloramine-T was examined in voltage clamped internally perfused crayfish and squid giant axons using the double sucrose gap and axial wire technique, respectively. Freshly prepared chloramine-T solution exerted two major actions on sodium channels: (a) an irreversible removal of the fast Na inactivation, and (b) a reversible block of the Na current. Both effects were observed when chloramine-T was applied internally or externally (5-10 mM) to axons. The first effect was studied in crayfish axons. We found that the removal of the fast Na inactivation did not depend on the states of the channel since the channel could be modified by chloramine-T at holding potential (from -80 to -100 mV) or at depolarized potential of -30 mV. After removal of fast Na inactivation, the slow inactivation mechanism was still present, and more channels could undergo slow inactivation. This result indicates that in crayfish axons the transition through the fast inactivated state is not a prerequisite for the slow inactivation to occur. During chloramine-T treatment, a distinct blocking phase occurred, which recovered upon washing out the drug. This second effect of chloramine-T was studied in detail in squid axons. After 24 h, chloramine-T solution lost its ability to remove fast inactivation but retained its blocking action. After removal of the fast Na inactivation, both fresh and aged chloramine-T solutions blocked the Na currents with a similar potency and in a voltage-dependent manner, being more pronounced at lower depolarizing potentials. A similar voltage-dependent block was observed with aged chloramine-T solution in an axon with intact inactivation. In contrast to the action of the fresh solution, the aged chloramine-T solution was found to accelerate the decay of Na currents.These results suggest that chloramine-T solution contains at least two active molecular forms that act at different sites in the Na channel. PMID:2444276

Surface and Bulk Characteristics of Cesium Iodide (CsI) coated Carbon (C) Fibers for High Power Microwave (HPM) Field Emission Cathodes

NASA Astrophysics Data System (ADS)

Vlahos, Vasilios; Morgan, Dane; Booske, John H.; Shiffler, Don

2008-11-01

CsI coated C fibers [1] are promising field emission cathodes for HPM applications. Ab initio computational modeling has shown that atomically-thin CsI coatings reduce the work function of C substrates by a surface dipole mechanism [2]. Characterization measurements of the composition and morphology of the CsI-coated C fibers are underway for determining the properties and characteristics of the following important regions of the fiber: (i) the surface on the tip of the fiber where the majority of electron emission is believed to occur, (ii) the surface covering the body of the fiber and its role on the emission properties of the system, and (iii) the interior volume of the fiber and its effects on the CsI surface re-supply process and rate. The results will be interpreted in terms of surface electronic properties and theoretical electron emission models. [1]D. Shiffler, et al., Phys. Plasmas 11 (2004) 1680. [2]V.Vlahos et al., Appl. Phys. Lett. 91 (2007) 144102.

Energy Efficiency Optimization in Relay-Assisted MIMO Systems With Perfect and Statistical CSI

NASA Astrophysics Data System (ADS)

Zappone, Alessio; Cao, Pan; Jorswieck, Eduard A.

2014-01-01

A framework for energy-efficient resource allocation in a single-user, amplify-and-forward relay-assisted MIMO system is devised in this paper. Previous results in this area have focused on rate maximization or sum power minimization problems, whereas fewer results are available when bits/Joule energy efficiency (EE) optimization is the goal. The performance metric to optimize is the ratio between the system's achievable rate and the total consumed power. The optimization is carried out with respect to the source and relay precoding matrices, subject to QoS and power constraints. Such a challenging non-convex problem is tackled by means of fractional programming and and alternating maximization algorithms, for various CSI assumptions at the source and relay. In particular the scenarios of perfect CSI and those of statistical CSI for either the source-relay or the relay-destination channel are addressed. Moreover, sufficient conditions for beamforming optimality are derived, which is useful in simplifying the system design. Numerical results are provided to corroborate the validity of the theoretical findings.

A new approach to increase the two-dimensional detection probability of CSI algorithm for WAS-GMTI mode

NASA Astrophysics Data System (ADS)

Yan, H.; Zheng, M. J.; Zhu, D. Y.; Wang, H. T.; Chang, W. S.

2015-07-01

When using clutter suppression interferometry (CSI) algorithm to perform signal processing in a three-channel wide-area surveillance radar system, the primary concern is to effectively suppress the ground clutter. However, a portion of moving target's energy is also lost in the process of channel cancellation, which is often neglected in conventional applications. In this paper, we firstly investigate the two-dimensional (radial velocity dimension and squint angle dimension) residual amplitude of moving targets after channel cancellation with CSI algorithm. Then, a new approach is proposed to increase the two-dimensional detection probability of moving targets by reserving the maximum value of the three channel cancellation results in non-uniformly spaced channel system. Besides, theoretical expression of the false alarm probability with the proposed approach is derived in the paper. Compared with the conventional approaches in uniformly spaced channel system, simulation results validate the effectiveness of the proposed approach. To our knowledge, it is the first time that the two-dimensional detection probability of CSI algorithm is studied.

Measuring Integration of Cancer Services to Support Performance Improvement: The CSI Survey

PubMed Central

Dobrow, Mark J.; Paszat, Lawrence; Golden, Brian; Brown, Adalsteinn D.; Holowaty, Eric; Orchard, Margo C.; Monga, Neerav; Sullivan, Terrence

2009-01-01

Objective: To develop a measure of cancer services integration (CSI) that can inform clinical and administrative decision-makers in their efforts to monitor and improve cancer system performance. Methods: We employed a systematic approach to measurement development, including review of existing cancer/health services integration measures, key-informant interviews and focus groups with cancer system leaders. The research team constructed a Web-based survey that was field- and pilot-tested, refined and then formally conducted on a sample of cancer care providers and administrators in Ontario, Canada. We then conducted exploratory factor analysis to identify key dimensions of CSI. Results: A total of 1,769 physicians, other clinicians and administrators participated in the survey, responding to a 67-item questionnaire. The exploratory factor analysis identified 12 factors that were linked to three broader dimensions: clinical, functional and vertical system integration. Conclusions: The CSI Survey provides important insights on a range of typically unmeasured aspects of the coordination and integration of cancer services, representing a new tool to inform performance improvement efforts. PMID:20676250

Challenges to Scaling CIGS Photovoltaics

NASA Astrophysics Data System (ADS)

Stanbery, B. J.

2011-03-01

The challenges of scaling any photovoltaic technology to terawatts of global capacity are arguably more economic than technological or resource constraints. All commercial thin-film PV technologies are based on direct bandgap semiconductors whose absorption coefficient and bandgap alignment with the solar spectrum enable micron-thick coatings in lieu to hundreds of microns required using indirect-bandgap c-Si. Although thin-film PV reduces semiconductor materials cost, its manufacture is more capital intensive than c-Si production, and proportional to deposition rate. Only when combined with sufficient efficiency and cost of capital does this tradeoff yield lower manufacturing cost. CIGS has the potential to become the first thin film technology to achieve the terawatt benchmark because of its superior conversion efficiency, making it the only commercial thin film technology which demonstrably delivers performance comparable to the dominant incumbent, c-Si. Since module performance leverages total systems cost, this competitive advantage bears directly on CIGS' potential to displace c-Si and attract the requisite capital to finance the tens of gigawatts of annual production capacity needed to manufacture terawatts of PV modules apace with global demand growth.

Optimization of dilute sulfuric acid pretreatment to maximize combined sugar yield from sugarcane bagasse for ethanol production.

PubMed

Benjamin, Y; Cheng, H; Görgens, J F

2014-01-01

Increasing fermentable sugar yields per gram of biomass depends strongly on optimal selection of varieties and optimization of pretreatment conditions. In this study, dilute acid pretreatment of bagasse from six varieties of sugarcane was investigated in connection with enzymatic hydrolysis for maximum combined sugar yield (CSY). The CSY from the varieties were also compared with the results from industrial bagasse. The results revealed considerable differences in CSY between the varieties. Up to 22.7 % differences in CSY at the optimal conditions was observed. The combined sugar yield difference between the best performing variety and the industrial bagasse was 34.1 %. High ratio of carbohydrates to lignin and low ash content favored the release of sugar from the substrates. At mild pretreatment conditions, the differences in bioconversion efficiency between varieties were greater than at severe condition. This observation suggests that under less severe conditions the glucose recovery was largely determined by chemical composition of biomass. The results from this study support the possibility of increasing sugar yields or improving the conversion efficiency when pretreatment optimization is performed on varieties with improved properties.

Microwave as an emerging technology for the treatment of biohazardous waste: A mini-review.

PubMed

Zimmermann, Klaus

2017-05-01

Microwave is an emerging technology to treat biohazardous waste, including material from healthcare facilities. A screen of the peer-reviewed literature shows that only limited information may be found in this area of work and, furthermore, analysis of the references reveals that sometimes not all necessary aspects for the appropriate use of the technology are considered. Very often conventional microwave technology is applied for the inactivation of pathogens, which might make sense for certain applications but, on the other hand, may lead to the misbelief that microwave systems cannot be used for the inactivation of a solid "dry" waste. However, conventional microwave units have no means to control the inactivation process, and especially moisture content. But there are a few sophisticated microwave technologies with appropriate measurements allowing a validated inactivation of biohazardous materials. These technologies are an effective tool for inactivation and some of them are commercially available. It must also be considered that the waste should be preferably inactivated either directly at the place where it is generated or biohazardous waste should be transported only in closed systems. Moreover, microwave technology presents a possibility to save energy costs in comparison to the more widely used autoclaves. This mini-review will discuss important aspects for the use of microwave technology for the treatment of biohazardous waste.

Role of the Local Anesthetic Receptor in the State-Dependent Inhibition of Voltage-Gated Sodium Channels by the Insecticide Metaflumizone

PubMed Central

von Stein, Richard T.

2012-01-01

Sodium channel inhibitor (SCI) insecticides selectively target voltage-gated sodium (Nav) channels in the slow-inactivated state by binding at or near the local anesthetic receptor within the sodium channel pore. Metaflumizone is a new insecticide for the treatment of fleas on domesticated pets and has recently been reported to block insect sodium channels in the slow-inactivated state, thereby implying that it is also a member of the SCI class. Using the two-electrode voltage-clamp technique, we examined metaflumizone inhibition of rat Nav1.4 sodium channels expressed in Xenopus laevis oocytes. Metaflumizone selectively inhibited Nav1.4 channels at potentials that promoted slow inactivation and shifted the voltage dependence of slow inactivation in the direction of hyperpolarization. Metaflumizone perfusion at a hyperpolarized holding potential also shifted the conductance-voltage curve for activation in the direction of depolarization and antagonized use-dependent lidocaine inhibition of fast-inactivated sodium channels, actions not previously observed with other SCI insecticides. We expressed mutated Nav1.4/F1579A and Nav1.4/Y1586A channels to investigate whether metaflumizone shares the domain IV segment S6 (DIV-S6) binding determinants identified for other SCI insecticides. Consistent with previous investigations of SCI insecticides on rat Nav1.4 channels, the F1579A mutation reduced sensitivity to block by metaflumizone, whereas the Y1586A mutation paradoxically increased the sensitivity to metaflumizone. We conclude that metaflumizone selectively inhibits slow-inactivated Nav1.4 channels and shares DIV-S6 binding determinants with other SCI insecticides and therapeutic drugs. However, our results suggest that metaflumizone interacts with resting and fast-inactivated channels in a manner that is distinct from other compounds in this insecticide class. PMID:22127519

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

Bean, Bruce Palmer

The effects of ether and halothane on membrane currents in the voltage clamped crayfish giant axon membrane were investigated. Concentrations of ether up to 300 mM and of halothane up to 32 mM had no effect on resting potential or leakage conductance. Ether and halothane reduced the size of sodium currents without changing the voltage dependence of the peak currents or their reversal potential. Ether and halothane also produced a reversible, dose-dependent speeding of sodium current decay at all membrane potentials. Ether reduced the time constants for inactivation, and also shifted the midpoint of the steady-state inactivation curve in themore » hyperpolarizing direction. Potassium currents were smaller with ether present, with no change in the voltage dependence of steady-state currents. The activation of potassium channels was faster with ether present. There was no apparent change in the capacitance of the crayfish giant axon membrane with ether concentrations of up to 100 mM. Experiments on sodium channel inactivation kinetics were performed using 4-aminopyridine to block potassium currents. Sodium currents decayed with a time course generally fit well by a single exponential. The time constant of decay was a steep function of voltage, especially in the negative resistance region of the peak current vs voltage relation.The time course of inactivation was very similar to that of the decay of the current at the same potential. The measurement of steady-state inactivation curves with different test pulses showed no shifts along the voltage asix. The voltage-dependence of the integral of sodium conductance was measured to test models of sodium channel inactivation in which channels must open before inactivating; the results appear inconsistent with some of the simplest cases of such models.« less

Enhanced blue responses in nanostructured Si solar cells by shallow doping

NASA Astrophysics Data System (ADS)

Cheon, Sieun; Jeong, Doo Seok; Park, Jong-Keuk; Kim, Won Mok; Lee, Taek Sung; Lee, Heon; Kim, Inho

2018-03-01

Optimally designed Si nanostructures are very effective for light trapping in crystalline silicon (c-Si) solar cells. However, when the lateral feature size of Si nanostructures is comparable to the junction depth of the emitter, dopant diffusion in the lateral direction leads to excessive doping in the nanostructured emitter whereby poor blue responses arise in the external quantum efficiency (EQE). The primary goal of this study is to find the correlation of emitter junction depth and carrier collection efficiency in nanostructured c-Si solar cells in order to enhance the blue responses. We prepared Si nanostructures of nanocone shape by colloidal lithography, with silica beads of 520 nm in diameter, followed by a reactive ion etching process. c-Si solar cells with a standard cell architecture of an Al back surface field were fabricated varying the emitter junction depth. We varied the emitter junction depth by adjusting the doping level from heavy doping to moderate doping to light doping and achieved greatly enhanced blue responses in EQE from 47%-92% at a wavelength of 400 nm. The junction depth analysis by secondary ion mass-spectroscopy profiling and the scanning electron microscopy measurements provided us with the design guide of the doping level depending on the nanostructure feature size for high efficiency nanostructured c-Si solar cells. Optical simulations showed us that Si nanostructures can serve as an optical resonator to amplify the incident light field, which needs to be considered in the design of nanostructured c-Si solar cells.

Potential-induced degradation in photovoltaic modules: a critical review

DOE PAGES

Luo, Wei; Khoo, Yong Sheng; Hacke, Peter; ...

2016-11-21

Potential-induced degradation (PID) has received considerable attention in recent years due to its detrimental impact on photovoltaic (PV) module performance under field conditions. Both crystalline silicon (c-Si) and thin-film PV modules are susceptible to PID. While extensive studies have already been conducted in this area, the understanding of the PID phenomena is still incomplete and it remains a major problem in the PV industry. Herein, a critical review of the available literature is given to serve as a one-stop source for understanding the current status of PID research. This article also aims to provide an overview of future research pathsmore » to address PID-related issues. This paper consists of three parts. In the first part, the modelling of leakage current paths in the module package is discussed. The PID mechanisms in both c-Si and thin-film PV modules are also comprehensively reviewed. The second part summarizes various test methods to evaluate PV modules for PID. The last part focuses on studies related to PID in the omnipresent p-type c-Si PV modules. The dependence of temperature, humidity and voltage on the progression of PID is examined. Preventive measures against PID at the cell, module and system levels are illustrated. Moreover, PID recovery in standard p-type c-Si PV modules is also studied. Most of the findings from p-type c-Si PV modules are also applicable to other PV module technologies.« less

Influence of radiotherapy treatment concept on the outcome of patients with localized ependymomas.

PubMed

Combs, Stephanie E; Kelter, Verena; Welzel, Thomas; Behnisch, Wolfgang; Kulozik, Andreas E; Bischof, Marc; Hof, Holger; Debus, Jürgen; Schulz-Ertner, Daniela

2008-07-15

To assess the outcome of 57 patients with localized ependymomas treated with radiotherapy (RT). Fifty-seven patients with localized ependymomas were treated with RT. Histology was myxopapillary ependymoma (n = 4), ependymoma (n = 23), and anaplastic ependymoma (n = 30). In 16 patients, irradiation of the craniospinal axis (CSI) was performed with a median dose of 20 Gy. Forty-one patients were treated with local RT, with a local dose of 45 Gy to the posterior fossa, including a boost to the tumor bed of 9 Gy. In 19 patients, the tumor bed was irradiated with a median dose of 54 Gy. Overall survival after primary diagnosis was 83% and 71% at 3 and 5 years. Five-year overall survival was 80% in low-grade and 79% in high-grade tumors. Survival from RT was 79% at 3 and 64% at 5 years. We could not show a significant difference in overall survival between CSI and local RT only. Freedom of local failure was 67% at 5 years in patients treated with CSI and 60% at 5 years after local RT. A rate of 83% for distant failure-free survival could be observed in the CSI group as opposed to 93% in the group receiving local RT only. Local RT in patients with localized tumors is equieffective to CSI. The radiation oncologist must keep in mind that patients with localized ependymomas benefit from local doses > or =45 Gy.

[Overload in the informal caregivers of patients with multiple comorbidities in an urban area].

PubMed

Álvarez-Tello, Margarita; Casado-Mejía, Rosa; Ortega-Calvo, Manuel; Ruiz-Arias, Esperanza

2012-01-01

The aim of the study was, to determine the profile of the family caregiver of patients with multiple pathologies, identify factors associated with overload, and construct predictive models using items from the Caregiver Strain Index (CSI). A cross-sectional study of caregivers of patients with multiple comorbidities who attended an urban health centre. Data were collected from health records and questionnaires (Barthel index, Pfeiffer index, and CSI). Statistical analysis was performed using measures of central tendency and dispersion, and by building multivariate models with binary logistic regression with the CSI items as predictors (program R version 2.14.0). The sample included 67 caregivers, with a mean age of 64.69 years (standard deviation=12.71, median 62 years), of whom 74.6% were women, 35.8% were wives, and 32.8% were daughters. The level of dependence of the patients cared for was total/severe in 77.6%, and moderate in 12% (Barthel), and 47.8% had some level of cognitive impairment (Pfeiffer). A CSI equal or greater than 7 was seen in 47.8% of caregivers, identifying life problems in more than 40% of them such as, restriction of social life, physical exertion, discomfort with change, bad behaviour, personal and family emotional changes, and sleep disturbances. Item 4 of the CSI, analysing the social restriction, was the one that showed a greater significance in the predictive multivariate model. Item 12 (economic burden) was the most significant with age in patients with cognitive impairment. Women tend to take the role of caregiver at an earlier age than men in the urban environment studied, and items from CSI showed that items 4 (social restrictions) and 12 (economic burden) have more significance in the predictive models constructed with Binary Logistic Regression. Copyright © 2012 Elsevier España, S.L. All rights reserved.

Genomic mutational analysis of the impact of the classical strain improvement program on β-lactam producing Penicillium chrysogenum.

PubMed

Salo, Oleksandr V; Ries, Marco; Medema, Marnix H; Lankhorst, Peter P; Vreeken, Rob J; Bovenberg, Roel A L; Driessen, Arnold J M

2015-11-14

Penicillium chrysogenum is a filamentous fungus that is employed as an industrial producer of β-lactams. The high β-lactam titers of current strains is the result of a classical strain improvement program (CSI) starting with a wild-type like strain more than six decades ago. This involved extensive mutagenesis and strain selection for improved β-lactam titers and growth characteristics. However, the impact of the CSI on the secondary metabolism in general remains unknown. To examine the impact of CSI on secondary metabolism, a comparative genomic analysis of β-lactam producing strains was carried out by genome sequencing of three P. chrysogenum strains that are part of a lineage of the CSI, i.e., strains NRRL1951, Wisconsin 54-1255, DS17690, and the derived penicillin biosynthesis cluster free strain DS68530. CSI has resulted in a wide spread of mutations, that statistically did not result in an over- or underrepresentation of specific gene classes. However, in this set of mutations, 8 out of 31 secondary metabolite genes (20 polyketide synthases and 11 non-ribosomal peptide synthetases) were targeted with a corresponding and progressive loss in the production of a range of secondary metabolites unrelated to β-lactam production. Additionally, key Velvet complex proteins (LeaA and VelA) involved in global regulation of secondary metabolism have been repeatedly targeted for mutagenesis during CSI. Using comparative metabolic profiling, the polyketide synthetase gene cluster was identified that is responsible for sorbicillinoid biosynthesis, a group of yellow-colored metabolites that are abundantly produced by early production strains of P. chrysogenum. The classical industrial strain improvement of P. chrysogenum has had a broad mutagenic impact on metabolism and has resulted in silencing of specific secondary metabolite genes with the concomitant diversion of metabolism towards the production of β-lactams.

Electrical interface characteristics (I-V), optical time of flight measurements, and the x-ray (20 keV) signal response of amorphous-selenium/crystalline-silicon heterojunction structures

NASA Astrophysics Data System (ADS)

Hunter, David M.; Ho, Chu An; Belev, George; De Crescenzo, Giovanni; Kasap, Safa O.; Yaffe, Martin J.

2011-03-01

We have investigated the dark current, optical TOF (time of flight) properties, and the X-ray response of amorphousselenium (a-Se)/crystalline-silicon (c-Si) heterostructures for application in digital radiography. The structures have been studied to determine if an x-ray generated electron signal, created in an a-Se layer, could be directly transferred to a c-Si based readout device such as a back-thinned CCD (charge coupled device). A simple first order band-theory of the structure indicates that x-ray generated electrons should transfer from the a-Se to the c-Si, while hole transfer from p-doped c-Si to the a-Se should be blocked, permitting a low dark signal as required. The structures we have tested have a thin metal bias electrode on the x-ray facing side of the a-Se which is deposited on the c-Si substrate. The heterostructures made with pure a-Se deposited on epitaxial p-doped (5×10 14 cm-3) c-Si exhibited very low dark current of 15 pA cm-2 at a negative bias field of 10 V μm-1 applied to the a-Se. The optical TOF (time of flight) measurements show that the applied bias drops almost entirely across the a-Se layer and that the a-Se hole and electron mobilities are within the range of commonly accepted values. The x-ray signal measurements demonstrate the structure has the expected x-ray quantum efficiency. We have made a back-thinned CCD coated with a-Se and although most areas of the device show a poor x-ray response, it does contain small regions which do work properly with the expected x-ray sensitivity. Improved understanding of the a-Se/c-Si interface and preparation methods should lead to properly functioning devices.

Inhibition of flavivirus infections by antisense oligomers specifically suppressing viral translation and RNA replication.

PubMed

Deas, Tia S; Binduga-Gajewska, Iwona; Tilgner, Mark; Ren, Ping; Stein, David A; Moulton, Hong M; Iversen, Patrick L; Kauffman, Elizabeth B; Kramer, Laura D; Shi, Pei-Yong

2005-04-01

RNA elements within flavivirus genomes are potential targets for antiviral therapy. A panel of phosphorodiamidate morpholino oligomers (PMOs), whose sequences are complementary to RNA elements located in the 5'- and 3'-termini of the West Nile (WN) virus genome, were designed to anneal to important cis-acting elements and potentially to inhibit WN infection. A novel Arg-rich peptide was conjugated to each PMO for efficient cellular delivery. These PMOs exhibited various degrees of antiviral activity upon incubation with a WN virus luciferase-replicon-containing cell line. Among them, PMOs targeting the 5'-terminal 20 nucleotides (5'End) or targeting the 3'-terminal element involved in a potential genome cyclizing interaction (3'CSI) exhibited the greatest potency. When cells infected with an epidemic strain of WN virus were treated with the 5'End or 3'CSI PMO, virus titers were reduced by approximately 5 to 6 logs at a 5 muM concentration without apparent cytotoxicity. The 3'CSI PMO also inhibited mosquito-borne flaviviruses other than WN virus, and the antiviral potency correlated with the conservation of the targeted 3'CSI sequences of specific viruses. Mode-of-action analyses showed that the 5'End and 3'CSI PMOs suppressed viral infection through two distinct mechanisms. The 5'End PMO inhibited viral translation, whereas the 3'CSI PMO did not significantly affect viral translation but suppressed RNA replication. The results suggest that antisense PMO-mediated blocking of cis-acting elements of flavivirus genomes can potentially be developed into an anti-flavivirus therapy. In addition, we report that although a full-length WN virus containing a luciferase reporter (engineered at the 3' untranslated region of the genome) is not stable, an early passage of this reporting virus can be used to screen for inhibitors against any step of the virus life cycle.

A Multimodal Approach Including Craniospinal Irradiation Improves the Treatment Outcome of High-risk Intracranial Nongerminomatous Germ Cell Tumors

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

Kim, Jun Won; Kim, Woo Chul; Cho, Jae Ho

2012-11-01

Purpose: To evaluate whether a multimodal approach including craniospinal irradiation (CSI) improves treatment outcome in nongerminomatous germ cell tumor (NGGCT) patients. Methods and Materials: We reviewed the records of 32 patients with NGGCTs. Fourteen patients belonged to the intermediate prognosis group (immature teratoma, teratoma with malignant transformation, and mixed tumors mainly composed of germinoma or teratoma), and 18 patients belonged to the poor prognosis group (other highly malignant tumors). Patients with pure germinoma or mature teratoma were excluded from this study. Nineteen patients were treated with a combination of surgery, chemotherapy, and radiotherapy (RT); 9 patients received chemotherapy plus RT;more » 3 patients received surgery plus RT; and 1 patient received RT alone. Twenty-seven patients received CSI with a median of 36 Gy (range, 20-41 Gy) plus focal boost of 18-30.6 Gy, and 5 patients received whole-brain RT (WBRT) (20-36 Gy) or focal RT (50.4-54 Gy). The rate of total and subtotal resection was 71.9%. The median follow-up for surviving patients was 121 months. Results: Treatment failed in 7 patients. Three of the 5 patients who received focal RT or WBRT had local failure. Four cerebrospinal fluid (CSF) failures occurred after CSI. No failure occurred in the intermediate prognosis group. Ten-year recurrence-free survival (RFS) and overall survival (OS) for all patients were 77.6% and 74.6%, respectively. Ten-year RFS for the intermediate and poor prognosis groups were 100% and 61.1%, respectively (p = 0.012). OS for the two groups were 85.1% and 66.7%, respectively (p = 0.215). Tumor histology and CSI were significant prognostic factors for RFS, and CSI was significantly associated with OS. Conclusions: A multimodal approach was effective for treating NGGCTs. CSI should be considered for patients with poor prognostic histology.« less

A manual physical therapy approach versus subacromial corticosteroid injection for treatment of shoulder impingement syndrome: a protocol for a randomised clinical trial

PubMed Central

Boyles, Robert E; Cleland, Joshua A; Brown, David L

2011-01-01

Introduction Corticosteroid injections (CSI) are a recommended and often-used first-line intervention for shoulder impingement syndrome (SIS) in primary care and orthopaedic settings. Manual physical therapy (MPT) offers a non-invasive approach with negligible risk for managing SIS. There is limited evidence to suggest significant long-term improvements in pain, strength and disability with the use of MPT, and there are conflicting reports from systematic reviews that question the long-term efficacy of CSI. Specifically, the primary objective is to compare the effect of CSI and MPT on pain and disability in subjects with SIS at 12 months. Design This pragmatic randomised clinical trial will be a mixed-model 2×5 factorial design. The independent variables are treatment (MPT and CSI) and time with five levels from baseline to 1 year. The primary dependent variable is the Shoulder Pain and Disability Index, and the secondary outcome measures are the Global Rating of Change and the Numeric Pain Rating Scale. For each ANOVA, the hypothesis of interest will be the two-way group-by-time interaction. Methods and analysis The authors plan to recruit 104 participants meeting established impingement criteria. Following examination and enrolment, eligible participants will be randomly allocated to receive a pragmatic approach of either CSI or MPT. The MPT intervention will consist of six sessions, and the CSI intervention will consist of one to three sessions. All subjects will continue to receive usual care. Subjects will be followed for 12 months. Dissemination and ethics The protocol was approved by the Madigan Army Medical Center Institutional Review Board. The results may have an impact on clinical practice guidelines. This study was funded in part by the Orthopaedic Physical Therapy Products Grant through the American Academy of Orthopaedic Manual Physical Therapists. Trial Registration http://clinicaltrials.gov/ NCT01190891. PMID:22021870

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

Mori, Koichiro, E-mail: kmori@iis.u-tokyo.ac.jp; Christodoulou, Aris, E-mail: aris.christodoulou@ucl.ac.uk

The purpose of this paper is to discuss conceptual requirements for a City Sustainability Index (CSI) and to review existing major sustainability indices/indicators in terms of the requirements. The following indices are reviewed: Ecological Footprint (EF), Environmental Sustainability Index (ESI), Dashboard of Sustainability (DS), Welfare Index, Genuine Progress Indicator (GPI), Index of Sustainable Economic Welfare, City Development Index, emergy/exergy, Human Development Index (HDI), Environmental Vulnerability Index (EVI), Environmental Policy Index (EPI), Living Planet Index (LPI), Environmentally-adjusted Domestic Product (EDP), Genuine Saving (GS), and some applications of composite indices or/and multivariate indicators to local or regional context as case studies. Themore » key conceptual requirements for an adequate CSI are: (i) to consider environmental, economic and social aspects (the triple bottom line of sustainability) from the viewpoint of strong sustainability; (ii) to capture external impacts (leakage effects) of city on other areas beyond the city boundaries particularly in terms of environmental aspects; (iii) to create indices/indicators originally for the purpose of assessing city sustainability; and (iv) to be able to assess world cities in both developed and developing countries using common axes of evaluation. Based on the review, we conclude that it is necessary to create a new CSI that enables us to assess and compare cities' sustainability performance in order to understand the global impact of cities on the environment and human life as compared with their economic contribution. In the future, the CSI will be able to provide local authorities with guidance toward sustainable paths. - Highlights: Black-Right-Pointing-Pointer We derive the four key requirements for a new City Sustainability Index (CSI) system. Black-Right-Pointing-Pointer First, the triple bottom line must be considered in terms of strong sustainability. Black-Right-Pointing-Pointer Second, environmental leakage effects beyond city boundaries should be captured. Black-Right-Pointing-Pointer Third, 'city sustainability' should be originally considered when CSI is created. Black-Right-Pointing-Pointer Fourth, cities in developed and developing countries can be evaluated without bias.« less

SU-F-T-446: Improving Craniospinal Irradiation Technique Using Volumetric Modulated Arc Therapy (VMAT) Planning and Its Dosimetric Verification

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

Yang, X; Tejani, M; Jiang, X

2016-06-15

Purpose: The purpose of this study is to investigate a volumetric modulated arc therapy (VMAT) treatment planning technique for supine craniospinal irradiation (CSI). Evaluate the suitability of VMAT for CSI with dosimetric measurements and compare it to 3D conformal planning using specific plan metrics such as dose conformity, homogeneity, and dose of organs at risk (OAR). Methods: Ten CSI patients treated with conventional 3D technique were re-planned with VMAT. The PTV was contoured to include the whole contents of the brain and spinal canal with a uniform margin of 5 mm. VMAT plans were generated with two partial arcs coveringmore » the brain, two partial arcs for the superior portion of the spinal cord and two partial arcs covering the remaining inferior portion of the spinal cord. Conformity index (CI), heterogeneity indexes (HI) and max and mean doses of OAR were compared to 3D plans. VMAT plans were delivered onto an anthropomorphic phantom loaded with Gafchromic films and OSLDs placed at specific positions to evaluate the plan dose at the junctions and as well as the plan dose distributions. Results: This VMAT technique was validated with a clinical study of 10 patients. The average CI was 1.03±0.02 for VMAT plans and 1.96±0.32 for conformal plans. And the average HI was 1.15±0.01 for VMAT plans and 1.51±0.21 for conformal plans. The mean and max doses to the all OARs for VMAT plans were significantly lower than conformal plans. The measured dose in phantom for VAMT plans was comparable to the calculated dose in Eclipse and the doses at junctions were verified. Conclusion: VMAT CSI was able to achieve better dose conformity and heterogeneity as well as significantly reducing the dose to Heart, esophagus and larynx. VMAT CSI appears to be a dosimterically advantageous, faster delivery, has better reproducibility CSI treatment.« less

Vaccine recommendations for children and youth for the 2014/2015 influenza season.

PubMed

Moore, Dorothy L

2014-10-01

The Canadian Paediatric Society continues to encourage annual influenza vaccination for ALL children and youth ≥6 months of age. Recommendations from the National Advisory Committee on Immunization for the 2014/2015 influenza season include some important changes: Influenza vaccination is recommended for ALL individuals ≥6 months of age, with particular focus on those at high risk of influenza-related complications and their close contacts. Definitions of high-risk conditions and close contacts have not changed from those of 2013/2014.The preference for intranasal, live attenuated influenza vaccine (LAIV) over trivalent inactivated influenza vaccines for healthy children is restricted to individuals two to six years of age. There is insufficient evidence to recommend LAIV over trivalent inactivated influenza vaccines in older children or in children with chronic health conditions; either vaccine may be used unless there are specific contraindications.Quadrivalent influenza vaccines are expected to be available for the 2014/2015 season and may be used interchangeably with trivalent vaccines. They may offer improved protection.Trivalent or quadrivalent inactivated vaccines may be used in individuals with egg allergy; LAIV has not yet been evaluated in this population and is not recommended at this time.

Genomics reveals traces of fungal phenylpropanoid-flavonoid metabolic pathway in the f ilamentous fungus Aspergillus oryzae.

PubMed

Juvvadi, Praveen Rao; Seshime, Yasuyo; Kitamoto, Katsuhiko

2005-12-01

Fungal secondary metabolites constitute a wide variety of compounds which either play a vital role in agricultural, pharmaceutical and industrial contexts, or have devastating effects on agriculture, animal and human affairs by virtue of their toxigenicity. Owing to their beneficial and deleterious characteristics, these complex compounds and the genes responsible for their synthesis have been the subjects of extensive investigation by microbiologists and pharmacologists. A majority of the fungal secondary metabolic genes are classified as type I polyketide synthases (PKS) which are often clustered with other secondary metabolism related genes. In this review we discuss on the significance of our recent discovery of chalcone synthase (CHS) genes belonging to the type III PKS superfamily in an industrially important fungus, Aspergillus oryzae. CHS genes are known to play a vital role in the biosynthesis of flavonoids in plants. A comparative genome analyses revealed the unique character of A. oryzae with four CHS-like genes (csyA, csyB, csyC and csyD) amongst other Aspergilli (Aspergillus nidulans and Aspergillus fumigatus) which contained none of the CHS-like genes. Some other fungi such as Neurospora crassa, Fusarium graminearum, Magnaporthe grisea, Podospora anserina and Phanerochaete chrysosporium also contained putative type III PKSs, with a phylogenic distinction from bacteria and plants. The enzymatically active nature of these newly discovered homologues is expected owing to the conservation in the catalytic residues across the different species of plants and fungi, and also by the fact that a majority of these genes (csyA, csyB and csyD) were expressed in A. oryzae. While this finding brings filamentous fungi closer to plants and bacteria which until recently were the only ones considered to possess the type III PKSs, the presence of putative genes encoding other principal enzymes involved in the phenylpropanoid and flavonoid biosynthesis (viz., phenylalanine ammonia-lyase, cinnamic acid hydroxylase and p-coumarate CoA ligase) in the A. oryzae genome undoubtedly prove the extent of its metabolic diversity. Since many of these genes have not been identified earlier, knowledge on their corresponding products or activities remain undeciphered. In future, it is anticipated that these enzymes may be reasonable targets for metabolic engineering in fungi to produce agriculturally and nutritionally important metabolites.

Fatal cervical spine injuries: a Finnish nationwide register-based epidemiologic study on data from 1987 to 2010.

PubMed

Thesleff, Tuomo; Niskakangas, Tero; Luoto, Teemu M; Öhman, Juha; Ronkainen, Antti

2016-08-01

The number of cervical spine injuries (CSIs) is increasing. Cervical spine injuries are associated with high morbidity and mortality. Identifying those who are at risk for CSI-related death can help develop national and international interventions and policies to reduce mortality. This study aimed to determine the trends in the incidence and the characteristics of fatal CSIs in Finland over a 24-year study period from 1987 to 2010. A large nationwide, retrospective, register-based study was carried out. The population-based sample was collected from death certificates issued in Finland between 1987 and 2010. The death certificates were obtained from the official Cause-of-Death Register, coordinated by Statistics Finland, which covers all deaths occurring in Finland. Sociodemographics and injury- and death-related data were used for outcome measures. All death certificates issued in Finland (1987-2010) containing a CSI as the cause of death were carefully reviewed. A total of 2,041 fatal CSIs were identified. These constituted 0.17% of all deaths in Finland within the study period. The average annual incidence of fatal CSIs was 16.5 per million (range: 12.5-21.2). The majority of the victims were male (72.9%) and had concurrent spinal cord injury (83.0%). Traffic accidents (40.1%) and falls (45.0%) were the most common injury mechanisms. Almost one-third (29.8%) of the deaths were alcohol-related. Among the young victims (<60 years) with upper CSI (C0-C2), the majority (91.8%) died within 24 hours post-injury. One-third of elderly victims' (≥60 years) CSI-related deaths occurred after 1 week post-injury and were mostly (74.2%) caused by respiratory and circulatory system diseases. Within the 24-year period, the incidence of fatal CSIs (+2/million), as well as the average age of sustaining a fatal CSI (+13.5 years), increased markedly. Fall-induced accidents among elderly males were the most prominently increasing subpopulation of fatal CSI victims. In recent decades, fatal CSI incidence (death certificate-based) has increased, being 18.6 per million in Finland in 2010. Victims of fatal CSIs tend to be older than in the past, and for a substantial number of males, low-energy falls lead to cervical trauma and death. Copyright © 2015 Elsevier Inc. All rights reserved.

Development and Testing of a Method for Validating Chemical Inactivation of Ebola Virus.

PubMed

Alfson, Kendra J; Griffiths, Anthony

2018-03-13

Complete inactivation of infectious Ebola virus (EBOV) is required before a sample may be removed from a Biosafety Level 4 laboratory. The United States Federal Select Agent Program regulations require that procedures used to demonstrate chemical inactivation must be validated in-house to confirm complete inactivation. The objective of this study was to develop a method for validating chemical inactivation of EBOV and then demonstrate the effectiveness of several commonly-used inactivation methods. Samples containing infectious EBOV ( Zaire ebolavirus ) in different matrices were treated, and the sample was diluted to limit the cytopathic effect of the inactivant. The presence of infectious virus was determined by assessing the cytopathic effect in Vero E6 cells. Crucially, this method did not result in a loss of infectivity in control samples, and we were able to detect less than five infectious units of EBOV ( Zaire ebolavirus ). We found that TRIzol LS reagent and RNA-Bee inactivated EBOV in serum; TRIzol LS reagent inactivated EBOV in clarified cell culture media; TRIzol reagent inactivated EBOV in tissue and infected Vero E6 cells; 10% neutral buffered formalin inactivated EBOV in tissue; and osmium tetroxide vapors inactivated EBOV on transmission electron microscopy grids. The methods described herein are easily performed and can be adapted to validate inactivation of viruses in various matrices and by various chemical methods.

Trehalose delays the reversible but not the irreversible thermal denaturation of cutinase.

PubMed

Baptista, R P; Cabral, J M; Melo, E P

2000-12-20

The effect of trehalose (0.5 M) on the thermal stability of cutinase in the alkaline pH range was studied. The thermal unfolding induced by increasing temperature was analyzed in the absence and in the presence of trehalose according to a two-state model (which assumes that only the folded and unfolded states of cutinase were present). Trehalose delays the reversible unfolding. The midpoint temperature of the unfolding transition (Tm) increases by 4.0 degrees C and 2. 6 degrees C at pH 9.2 and 10.5, respectively, in the presence of trehalose. At pH 9.2 the thermal unfolding occurs at higher temperatures (Tm is 52.6 degrees C compared to 42.0 degrees C at pH 10.5) and a refolding yield of around 80% was obtained upon cooling. This pH value was chosen to study the irreversible inactivation (long-term stability) of cutinase. Temperatures in the transition range from folded to unfolded state were selected and the rate constants of irreversible inactivation determined. Inactivation followed first-order kinetics and trehalose reduced the observed rate constants of inactivation, pointing to a stabilizing effect on the irreversible inactivation step of thermal denaturation. However, if the contribution of reversible unfolding on the irreversible inactivation of cutinase was taken into account, i.e., considering the fraction of cutinase molecules in the reversible unfolded conformation, the intrinsic rate constants can be calculated. Based on the intrinsic rate constants it was concluded that trehalose does not delay the irreversible inactivation. This conclusion was further supported by comparing the activation energy of the irreversible inactivation in the absence and in the presence of trehalose. The apparent activation energy in the absence and in the presence of trehalose were 67 and 99 Kcal/mol, respectively. The activation energy calculated from intrinsic rate constants was higher in the absence (30 Kcal/mol) than in the presence of trehalose (16 Kcal/mol), showing that kinetics of the irreversible inactivation step increased in the presence of trehalose. In fact, trehalose stabilized only the reversible step of thermal denaturation of cutinase.

Cognitive Style Index: Further Investigation of the Factor Structure with an American Student Sample

ERIC Educational Resources Information Center

Backhaus, Kristin; Liff, Joshua P.

2007-01-01

The present study investigates the factor structure of the Cognitive Style Index (CSI), comparing the unitary, bipolar continuum of intuition-analysis, the theory upon which the CSI is predicated, with the two-factor theory of cognitive style. We conducted both confirmatory and exploratory factor analyses on data from a sample of 222 American…

Impact of the Career Style Interview on Individuals with Career Concerns

ERIC Educational Resources Information Center

Rehfuss, Mark C.; Del Corso, Jennifer; Galvin, Kevin; Wykes, Scott

2011-01-01

A total of 18 participants ranging in age from 20 to 55 were administered the career style interview (CSI) and completed a follow-up interview 2 weeks later. Consensual qualitative research analysis of follow-up interview data indicated that after completing the CSI, participants "generally" felt helped and also "typically" experienced awareness,…

CSI Web Adventures: A Forensics Virtual Apprenticeship for Teaching Science and Inspiring STEM Careers

ERIC Educational Resources Information Center

Miller, Leslie; Chang, Ching-I; Hoyt, Daniel

2010-01-01

CSI: The Experience, a traveling museum exhibit and a companion web adventure, was created through a grant from the National Science Foundation as a potential model for informal learning. The website was designed to enrich and complement the exhibit by modeling the forensic process. Substantive science, real-world lab techniques, and higher-level…

10 CFR 71.59 - Standards for arrays of fissile material packages.

Code of Federal Regulations, 2012 CFR

2012-01-01

... the stack by water: (1) Five times “N” undamaged packages with nothing between the packages would be.... The value of the CSI may be zero provided that an unlimited number of packages are subcritical, such...) of this section. Any CSI greater than zero must be rounded up to the first decimal place. (c) For a...

10 CFR 71.59 - Standards for arrays of fissile material packages.

Code of Federal Regulations, 2013 CFR

2013-01-01

... the stack by water: (1) Five times “N” undamaged packages with nothing between the packages would be.... The value of the CSI may be zero provided that an unlimited number of packages are subcritical, such...) of this section. Any CSI greater than zero must be rounded up to the first decimal place. (c) For a...

10 CFR 71.59 - Standards for arrays of fissile material packages.

Code of Federal Regulations, 2014 CFR

2014-01-01

... the stack by water: (1) Five times “N” undamaged packages with nothing between the packages would be.... The value of the CSI may be zero provided that an unlimited number of packages are subcritical, such...) of this section. Any CSI greater than zero must be rounded up to the first decimal place. (c) For a...

CSI related dynamics and control issues in space robotics

NASA Technical Reports Server (NTRS)

Schmitz, Eric; Ramey, Madison

1993-01-01

The research addressed includes: (1) CSI issues in space robotics; (2) control of elastic payloads, which includes 1-DOF example, and 3-DOF harmonic drive arm with elastic beam; and (3) control of large space arms with elastic links, which includes testbed description, modeling, and experimental implementation of colocated PD and end-point tip position controllers.

Copper-silver ionization at a US hospital: interaction of treated drinking water with plumbing materials, aesthetics and other considerations

EPA Science Inventory

Tap water sampling and surface analysis of copper pipe/bathroom porcelain were performed to explore the fate of copper and silver during the first nine months of copper-silver ionization (CSI) applied to cold and hot water at a hospital in Cincinnati, Ohio. Ions dosed by CSI into...

Exploring K-3 Teachers' Implementation of Comprehension Strategy Instruction (CSI) Using Expectancy-Value Theory

ERIC Educational Resources Information Center

Foley, Laura S.

2011-01-01

This research investigated factors that influence the implementation levels of evidence-based comprehension strategy instruction (CSI) among K-3 teachers. An explanatory design was chosen to gather and probe the data. Quantitative data were gathered via a mailed survey distributed through a representative sample of the 40 school districts (through…

The Lesbian, Gay and Bisexual Affirmative Counseling Self-Efficacy Inventory (LGB-CSI): Development, Validation, and Training Implications

ERIC Educational Resources Information Center

Dillon, Frank; Worthington, Roger L.

2003-01-01

Five studies on the development of the Lesbian, Gay, and Bisexual Affirmative Counseling Self-Efficacy Inventory (LGB-CSI) were conducted. Exploratory and confirmatory factor analyses of an initial pool of 64 items yielded 5 factors that assess counselor self-efficacy to perform lesbian, gay, and bisexual (LGB) affirmative counseling behaviors…

77 FR 65438 - In the Matter of China Voice Holding Corp., China Yongxin Pharmaceuticals, Inc., Creative...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-26

... Commission that there is a lack of current and accurate information concerning the securities of CSI Computer... SECURITIES AND EXCHANGE COMMISSION [File No. 500-1] In the Matter of China Voice Holding Corp... Telecommunications.com , Inc. (n/k/a Fleet Management Solutions, Inc.), CSI Computer Specialists, Inc., and CST...

The CSI Academy: Encouraging Diverse Students to Consider Science Careers and Science Teaching

ERIC Educational Resources Information Center

Kaye, Karen; Turner, John F.; Emigh, James

2011-01-01

The CSI academies employed a multi-layered, collaborative approach to encourage diverse students to consider STEM careers, including science teaching. The academies recruited a diverse group of high school students. This was due, in large part, to the creation of a unique selection process that identified students with unrealized potential. The…

10 CFR 71.59 - Standards for arrays of fissile material packages.

Code of Federal Regulations, 2011 CFR

2011-01-01

... fissile material package shall derive a number “N” based on all the following conditions being satisfied.... The value of the CSI may be zero provided that an unlimited number of packages are subcritical, such...) of this section. Any CSI greater than zero must be rounded up to the first decimal place. (c) For a...

10 CFR 71.59 - Standards for arrays of fissile material packages.

Code of Federal Regulations, 2010 CFR

2010-01-01

... fissile material package shall derive a number “N” based on all the following conditions being satisfied.... The value of the CSI may be zero provided that an unlimited number of packages are subcritical, such...) of this section. Any CSI greater than zero must be rounded up to the first decimal place. (c) For a...

Beyond Grand Rounds: A Comprehensive and Sequential Intervention to Improve Identification of Delirium

ERIC Educational Resources Information Center

Ramaswamy, Ravishankar; Dix, Edward F.; Drew, Janet E.; Diamond, James J.; Inouye, Sharon K.; Roehl, Barbara J. O.

2011-01-01

Purpose of the Study: Delirium is a widespread concern for hospitalized seniors, yet is often unrecognized. A comprehensive and sequential intervention (CSI) aiming to effect change in clinician behavior by improving knowledge about delirium was tested. Design and Methods: A 2-day CSI program that consisted of progressive 4-part didactic series,…

Microcrystalline silicon growth for heterojunction solar cells

NASA Technical Reports Server (NTRS)

Iles, P. A.; Leung, D. C.; Fang, P. H.

1983-01-01

A total of sixteen runs of e-beam vacuum deposition of p type microcrystalline Si (m-Si) films were attempted on n type or p-n junction single crystalline Si (C-Si) substrates. The m-Si film thickness varied from .15 to .7 um and metal contacts were deposited after plasma hydrogenation. The p-m-Si on n-c-Si structure had a Voc of up to 490 m V while no Voc improvements were observed in the p-m-Si on p-n C-Si structure against p-n controls. Both CFF and Jsc were lower than control. Possible problem areas were interfaced between m-Si and C-si and the back contacts due to lack of sintering for fear of dehydrogenation.

Urease from Helicobacter pylori is inactivated by sulforaphane and other isothiocyanates

PubMed Central

Fahey, Jed W.; Stephenson, Katherine K.; Wade, Kristina L.; Talalay, Paul

2013-01-01

Infections by Helicobacter pylori are very common, causing gastroduodenal inflammation including peptic ulcers, and increasing the risk of gastric neoplasia. The isothiocyanate (ITC) sulforaphane [SF; 1-isothiocyanato-4-(methylsulfinyl)butane] derived from edible crucifers such as broccoli is potently bactericidal against Helicobacter, including antibiotic-resistant strains, suggesting a possible dietary therapy. Gastric H. pylori infections express high urease activity which generates ammonia, neutralizes gastric acidity, and promotes inflammation. The finding that SF inhibits (inactivates) urease (jack bean and Helicobacter) raised the issue of whether these properties might be functionally related. The rates of inactivation of urease activity depend on enzyme and SF concentrations and show first order kinetics. Treatment with SF results in time-dependent increases in the ultraviolet absorption of partially purified Helicobacter urease in the 280–340 nm region. This provides direct spectroscopic evidence for the formation of dithiocarbamates between the ITC group of SF and cysteine thiols of urease. The potencies of inactivation of Helicobacter urease by isothiocyanates structurally related to SF were surprisingly variable. Natural isothiocyanates closely related to SF, previously shown to be bactericidal (berteroin, hirsutin, phenethyl isothiocyanate, alyssin, and erucin), did not inactivate urease activity. Furthermore, SF is bactericidal against both urease positive and negative H. pylori strains. In contrast, some isothiocyanates such as benzoyl-ITC, are very potent urease inactivators, but are not bactericidal. The bactericidal effects of SF and other ITC against Helicobacter are therefore not obligatorily linked to urease inactivation, but may reduce the inflammatory component of Helicobacter infections. PMID:23583386

A study on the achievable data rate in massive MIMO system

NASA Astrophysics Data System (ADS)

Salh, Adeeb; Audah, Lukman; Shah, Nor Shahida M.; Hamzah, Shipun A.

2017-09-01

The achievable high data rates depend on the ability of massive multi-input-multi-output (MIMO) for the fifth-generation (5G) cellular networks, where the massive MIMO systems can support very high energy and spectral efficiencies. A major challenge in mobile broadband networks is how to support the throughput in the future 5G, where the highlight of 5G expected to provide high speed internet for every user. The performance massive MIMO system increase with linear minimum mean square error (MMSE), zero forcing (ZF) and maximum ratio transmission (MRT) when the number of antennas increases to infinity, by deriving the closed-form approximation for achievable data rate expressions. Meanwhile, the high signal-to-noise ratio (SNR) can be mitigated by using MMSE, ZF and MRT, which are used to suppress the inter-cell interference signals between neighboring cells. The achievable sum rate for MMSE is improved based on the distributed users inside cell, mitigated the inter-cell interference caused when send the same signal by other cells. By contrast, MMSE is better than ZF in perfect channel state information (CSI) for approximately 20% of the achievable sum rate.

Modeling and control of flexible space platforms with articulated payloads

NASA Technical Reports Server (NTRS)

Graves, Philip C.; Joshi, Suresh M.

1989-01-01

The first steps in developing a methodology for spacecraft control-structure interaction (CSI) optimization are identification and classification of anticipated missions, and the development of tractable mathematical models in each mission class. A mathematical model of a generic large flexible space platform (LFSP) with multiple independently pointed rigid payloads is considered. The objective is not to develop a general purpose numerical simulation, but rather to develop an analytically tractable mathematical model of such composite systems. The equations of motion for a single payload case are derived, and are linearized about zero steady-state. The resulting model is then extended to include multiple rigid payloads, yielding the desired analytical form. The mathematical models developed clearly show the internal inertial/elastic couplings, and are therefore suitable for analytical and numerical studies. A simple decentralized control law is proposed for fine pointing the payloads and LFSP attitude control, and simulation results are presented for an example problem. The decentralized controller is shown to be adequate for the example problem chosen, but does not, in general, guarantee stability. A centralized dissipative controller is then proposed, requiring a symmetric form of the composite system equations. Such a controller guarantees robust closed loop stability despite unmodeled elastic dynamics and parameter uncertainties.

Quantitative inactivation-mechanisms of P. digitatum and A. niger spores based on atomic oxygen dose

NASA Astrophysics Data System (ADS)

Ito, Masafumi; Hashizume, Hiroshi; Ohta, Takayuki; Hori, Masaru

2014-10-01

We have investigated inactivation mechanisms of Penicillium digitatum and Asperguills niger spores using atmospheric-pressure radical source quantitatively. The radical source was specially developed for supplying only neutral radicals without charged species and UV-light emissions. Reactive oxygen radical densities such as grand-state oxygen atoms, excited-state oxygen molecules and ozone were measured using VUV and UV absorption spectroscopies. The measurements and the treatments of spores were carried out in an Ar-purged chamber for eliminating the influences of OH, NOx and so on. The results revealed that the inactivation of spores can be explained by atomic-oxygen dose under the conditions employing neutral ROS irradiations. On the basis of the dose, we have observed the changes of intracellular organelles and membrane functions using TEM, SEM and confocal- laser fluorescent microscopy. From these results, we discuss the detail inactivation-mechanisms quantitatively based on atomic-oxygen dose.

Cardiac sodium channel Markov model with temperature dependence and recovery from inactivation.

PubMed Central

Irvine, L A; Jafri, M S; Winslow, R L

1999-01-01

A Markov model of the cardiac sodium channel is presented. The model is similar to the CA1 hippocampal neuron sodium channel model developed by Kuo and Bean (1994. Neuron. 12:819-829) with the following modifications: 1) an additional open state is added; 2) open-inactivated transitions are made voltage-dependent; and 3) channel rate constants are exponential functions of enthalpy, entropy, and voltage and have explicit temperature dependence. Model parameters are determined using a simulated annealing algorithm to minimize the error between model responses and various experimental data sets. The model reproduces a wide range of experimental data including ionic currents, gating currents, tail currents, steady-state inactivation, recovery from inactivation, and open time distributions over a temperature range of 10 degrees C to 25 degrees C. The model also predicts measures of single channel activity such as first latency, probability of a null sweep, and probability of reopening. PMID:10096885

The Development of Environmental Barrier Coatings for SiCSiC Ceramic Matrix Composites: Challenges and Opportunities

NASA Technical Reports Server (NTRS)

Zhu, Dongming

2014-01-01

Environmental barrier coatings (EBCs) and SiC/SiC ceramic matrix composites (CMCs) systems will play a crucial role in future turbine engines for hot-section component applications because of their ability to significantly increase engine operating temperatures, reduce engine weight and cooling requirements. The development of prime-reliant environmental barrier coatings is a key to enable the applications of the envisioned CMC components to help achieve next generation engine performance and durability goals. This paper will primarily address the performance requirements and design considerations of environmental barrier coatings for turbine engine applications. The emphasis is placed on current candidate environmental barrier coating systems for SiCSiC CMCs, their performance benefits and design limitations in long-term operation and combustion environments. Major technical barriers in developing advanced environmental barrier coating systems, the coating integrations with next generation CMC turbine components having improved environmental stability, cyclic durability and system performance will be described. The development trends for turbine environmental barrier coating systems by utilizing improved compositions, state-of-the-art processing methods, and simulated environment testing and durability modeling will be discussed.

PILA: Sub-Meter Localization Using CSI from Commodity Wi-Fi Devices

PubMed Central

Tian, Zengshan; Li, Ze; Zhou, Mu; Jin, Yue; Wu, Zipeng

2016-01-01

The aim of this paper is to present a new indoor localization approach by employing the Angle-of-arrival (AOA) and Received Signal Strength (RSS) measurements in Wi-Fi network. To achieve this goal, we first collect the Channel State Information (CSI) by using the commodity Wi-Fi devices with our designed three antennas to estimate the AOA of Wi-Fi signal. Second, we propose a direct path identification algorithm to obtain the direct signal path for the sake of reducing the interference of multipath effect on the AOA estimation. Third, we construct a new objective function to solve the localization problem by integrating the AOA and RSS information. Although the localization problem is non-convex, we use the Second-order Cone Programming (SOCP) relaxation approach to transform it into a convex problem. Finally, the effectiveness of our approach is verified based on the prototype implementation by using the commodity Wi-Fi devices. The experimental results show that our approach can achieve the median error 0.7 m in the actual indoor environment. PMID:27735879

PILA: Sub-Meter Localization Using CSI from Commodity Wi-Fi Devices.

PubMed

Tian, Zengshan; Li, Ze; Zhou, Mu; Jin, Yue; Wu, Zipeng

2016-10-10

The aim of this paper is to present a new indoor localization approach by employing the Angle-of-arrival (AOA) and Received Signal Strength (RSS) measurements in Wi-Fi network. To achieve this goal, we first collect the Channel State Information (CSI) by using the commodity Wi-Fi devices with our designed three antennas to estimate the AOA of Wi-Fi signal. Second, we propose a direct path identification algorithm to obtain the direct signal path for the sake of reducing the interference of multipath effect on the AOA estimation. Third, we construct a new objective function to solve the localization problem by integrating the AOA and RSS information. Although the localization problem is non-convex, we use the Second-order Cone Programming (SOCP) relaxation approach to transform it into a convex problem. Finally, the effectiveness of our approach is verified based on the prototype implementation by using the commodity Wi-Fi devices. The experimental results show that our approach can achieve the median error 0.7 m in the actual indoor environment.

Centromere inactivation and epigenetic modifications of a plant chromosome with three functional centromeres.

PubMed

Zhang, Wenli; Friebe, Bernd; Gill, Bikram S; Jiang, Jiming

2010-10-01

A chromosome with two functional centromeres is cytologically unstable and can only be stabilized when one of the two centromeres becomes inactivated via poorly understood mechanisms. Here, we report a transmissible chromosome with multiple centromeres in wheat. This chromosome encompassed one large and two small domains containing the centromeric histone CENH3. The two small centromeres are in a close vicinity and often fused as a single centromere on metaphase chromosomes. This fused centromere contained approximately 30% of the CENH3 compared to the large centromere. An intact tricentric chromosome was transmitted to about 70% of the progenies, which was likely a consequence of the dominating pulling capacity of the large centromere during anaphases of meiosis. The tricentric chromosome showed characteristics typical to dicentric chromosomes, including chromosome breaks and centromere inactivation. Remarkably, inactivation was always associated with the small centromeres, indicating that small centromeres are less likely to survive than large ones in dicentric chromosomes. The inactivation of the small centromeres also coincided with changes of specific histone modifications, including H3K27me2 and H3K27me3, of the pericentromeric chromatin.

Ecology and thermal inactivation of microbes in and on interplanetary space vehicle components

NASA Technical Reports Server (NTRS)

Reyes, A. L.

1974-01-01

Dry heat inactivation characteristics were compared for 4-6 (B. brevis) spores and microbes from the Cincinnati soil samples at 105, 112, and 125. Characterized were the survival curves of 4-6 (B. brevis) spores at 112, 115, 118, 120, and 125 C, and 1.2 microgram of water per ml of headspace air (closed tin-can system), and the morphological characteristics of 4-6 (B. brevis), 6-12 (B. lentus), 7-11 (B. coagulans), and B. subtilis var. niger spores by scanning electron microscopy.

Photodynamic Inactivation of Mammalian Viruses and Bacteriophages

PubMed Central

Costa, Liliana; Faustino, Maria Amparo F.; Neves, Maria Graça P. M. S.; Cunha, Ângela; Almeida, Adelaide

2012-01-01

Photodynamic inactivation (PDI) has been used to inactivate microorganisms through the use of photosensitizers. The inactivation of mammalian viruses and bacteriophages by photosensitization has been applied with success since the first decades of the last century. Due to the fact that mammalian viruses are known to pose a threat to public health and that bacteriophages are frequently used as models of mammalian viruses, it is important to know and understand the mechanisms and photodynamic procedures involved in their photoinactivation. The aim of this review is to (i) summarize the main approaches developed until now for the photodynamic inactivation of bacteriophages and mammalian viruses and, (ii) discuss and compare the present state of the art of mammalian viruses PDI with phage photoinactivation, with special focus on the most relevant mechanisms, molecular targets and factors affecting the viral inactivation process. PMID:22852040

1/f-Noise of open bacterial porin channels.

PubMed

Wohnsland, F; Benz, R

1997-07-01

General diffusion pores and specific porin channels from outer membranes of gram-negative bacteria were reconstituted into lipid bilayer membranes. The current noise of the channels was investigated for the different porins in the open state and in the ligand-induced closed state using fast Fourier transformation. The open channel noise exhibited 1/f-noise for frequencies up to 200 Hz. The 1/f-noise was investigated using the Hooge formula (Hooge, Phys. Lett. 29A: 139-140 (1969)), and the Hooge parameter alpha was calculated for all bacterial porins used in this study. The 1/f-noise was in part caused by slow inactivation and activation of porin channels. However, when care was taken that during the noise measurement no opening or closing of porin channels occurred, the Hooge Parameter alpha was a meaningful number for a given channel. A linear relationship was observed between alpha and the single-channel conductance, g, of the different porins. This linear relation between single-channel conductance and the Hooge parameter alpha could be qualitatively explained by assuming that the passing of an ion through a bacterial porin channel is-to a certain extent-influenced by nonlinear effects between channel wall and passing ion.

[The evoked activity of the lateral hypothalamus during extinction and differential inhibition].

PubMed

Vanetsian, G L

1995-01-01

Character of interaction between symmetric points of the cat's auditory cortex (A1) and the lateral hypothalamus (HL) was determined by calculating Spearman correlation coefficients between averaged summed sound-evoked activity (AEP) of the structures before, during elaboration, extinction and restoration, as well as differentiation of food-procuring conditioned reflex and in the eating full. Close mutual co-tuning between the cortex and hypothalamus characteristic for stable conditioned reflex was found to disrupted during its extinction, elaboration of differentiation and fullness eat inhibition due to entire reduction of hypothalamic AEP and disappearance of correlated with negativity of HL AEP "doubling" of the first positive wave of A1 AEP. Hyperactivity stage, expressed at the beginning of extinction and at the end of differentiation, preceded inactivation of hypothalamic afferents during elaboration of conditioned inhibition. The stage of hyperactivity, initiated by the elevated emotional state of the animal, testifies to an important role of emotional brain structures in the process of internal inhibition. The stage of HL and A1 hyperactivity initiated by emotional stress of the animal and following HL inactivation during inhibition of the conditioned response point to an important role of emotional subcortical brain structures in the mechanisms of inhibitory conditioning.

The Impact of Radiotherapy Fields in the Treatment of Patients With Choroid Plexus Carcinoma

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

Mazloom, Ali; Wolff, Johannes E.; Paulino, Arnold C., E-mail: apaulino@tmhs.or

2010-09-01

Purpose: To perform a comprehensive literature review and analysis of cases dealing with choroid plexus carcinoma (CPC) to determine the optimal radiotherapy (RT) treatment field. Methods and Materials: A PubMed search of English language articles from 1979 to 2008 was performed, yielding 33 articles with 56 patients who had available data regarding RT treatment field. The median age at diagnosis was 2.7 years (range, 1 month-53 years). Of 54 patients with data regarding type of surgery, 21 (38.9%) had complete resection. Chemotherapy was delivered to 27 (48%) as part of initial therapy. The RT treatment volume was the craniospinal axismore » in 38 (68%), whole brain in 9 (16%), and tumor/tumor bed in 9 (16%). Median follow-up for surviving patients was 40 months. Results: The 5-year overall survival and progression-free survival (PFS) rates were 59.5% and 37.2%, respectively. Complete resection (p = 0.035) and use of craniospinal irradiation (CSI; p = 0.025) were found to positively affect PFS. The 5-year PFS for patients who had CSI vs. whole brain and tumor/tumor bed RT were 44.2% and 15.3%. For the 19 patients who relapsed, 9 (47%) had a recurrence in the RT field, 6 (32%) had a recurrence outside the RT field, and 4 (21%) had a recurrence inside and outside the irradiated field. Conclusion: Patients with CPC who received CSI had better PFS compared with those receiving less than CSI. This study supports the use of CSI in the multimodality management of patients with CPC.« less

Bifocal Intracranial Germinoma: A Retrospective Analysis of Treatment Outcomes in 20 Patients and Review of the Literature

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

Weksberg, David C.; Shibamoto, Yuta; Paulino, Arnold C., E-mail: apaulino@tmhs.org

Purpose: Bifocal germinoma (BFG) is a rare intracranial neoplasm for which the choice of radiation therapy (RT) field is controversial. Some believe that BFG represents disseminated disease requiring craniospinal irradiation (CSI), whereas others believe that BFG represents localized disease and advocate for more limited fields. Methods and Materials: We analyzed 20 BFG patients at our institutions with classic bifocal lesions (pineal gland and suprasellar region). In addition, we identified 60 BFG patients from the literature. The RT fields, use of chemotherapy and extent of disease were recorded and analyzed for each patient. Results: There were 55 patients with bifocal lesionsmore » only (Group I), and 25 with bifocal lesions plus ventricular and/or CSF positive disease (Group II). The 5-year progression-free survival was 95% for Group I and 80% for Group II. In Group I, there were no failures in patients receiving CSI (n = 11), two spinal failures in those treated with more limited RT fields without chemotherapy (n = 17), and one spinal failure with chemotherapy (n = 23). In Group II, there were no failures in patients receiving CSI (n = 11), but four spinal failures were observed in patients receiving more limited RT fields with chemotherapy (n = 13); 1 patient who received whole-brain RT without chemotherapy experienced failure in the spine and brain. Conclusions: CSI is associated with excellent PFS in BFG. In Group I BFG patients, omission of spinal irradiation appears to be a reasonable approach, especially when chemotherapy is used. Patients with Group II BFG are best treated with CSI.« less

FaCSI: A block parallel preconditioner for fluid-structure interaction in hemodynamics

NASA Astrophysics Data System (ADS)

Deparis, Simone; Forti, Davide; Grandperrin, Gwenol; Quarteroni, Alfio

2016-12-01

Modeling Fluid-Structure Interaction (FSI) in the vascular system is mandatory to reliably compute mechanical indicators in vessels undergoing large deformations. In order to cope with the computational complexity of the coupled 3D FSI problem after discretizations in space and time, a parallel solution is often mandatory. In this paper we propose a new block parallel preconditioner for the coupled linearized FSI system obtained after space and time discretization. We name it FaCSI to indicate that it exploits the Factorized form of the linearized FSI matrix, the use of static Condensation to formally eliminate the interface degrees of freedom of the fluid equations, and the use of a SIMPLE preconditioner for saddle-point problems. FaCSI is built upon a block Gauss-Seidel factorization of the FSI Jacobian matrix and it uses ad-hoc preconditioners for each physical component of the coupled problem, namely the fluid, the structure and the geometry. In the fluid subproblem, after operating static condensation of the interface fluid variables, we use a SIMPLE preconditioner on the reduced fluid matrix. Moreover, to efficiently deal with a large number of processes, FaCSI exploits efficient single field preconditioners, e.g., based on domain decomposition or the multigrid method. We measure the parallel performances of FaCSI on a benchmark cylindrical geometry and on a problem of physiological interest, namely the blood flow through a patient-specific femoropopliteal bypass. We analyze the dependence of the number of linear solver iterations on the cores count (scalability of the preconditioner) and on the mesh size (optimality).

Long-term outcome after implantation of a suprachoroidal cyclosporine drug delivery device in horses with recurrent uveitis.

PubMed

Gilger, Brian C; Wilkie, David A; Clode, Allison B; McMullen, Richard J; Utter, Mary E; Komaromy, Andras M; Brooks, Dennis E; Salmon, Jacklin H

2010-09-01

To determine the long-term efficacy, complications, and duration of effect of a cyclosporine (CsA) suprachoroidal implant (CSI) in horses with equine recurrent uveitis (ERU). Horses with ERU were treated with a 6-mm diameter, 25 mg, reservoir matrix CsA implant in the deep sclera adjacent to the suprachoroidal space. Horses with follow-up >1 year were examined for frequency of uveitis episodes, complications, and vision at last recheck. Data from 151 eyes of 133 horses from the USA and Europe that had CsA devices implanted for ERU were reviewed. Follow-up time ranged from 13 to 85 months after surgery, with a mean and median follow-up time of 28.9 and 26.3 months, respectively. Overall, at last follow-up 78.8% of eyes were considered visual and the overall mean frequency of uveitis episodes after CSI was 0.09 ± SD 0.08 episodes per month. The most common complications leading to vision loss at last follow-up were persistent uveitis episodes (54%), glaucoma (22%), mature cataracts (16%), and retinal detachment (6%). Persistent uveitis episodes tended to be the highest cause of vision loss in horses with <24 months and >48 months of follow-up. This study demonstrated the long-term maintenance of vision of horses with ERU implanted with a CSI. The increased vision loss related to uveitis episode of inflammation in eyes after the likely depletion of CsA from the CSI suggests that a repeat CSI may be required at or before 48 months after surgery.

Wafer-Scale Integration of Inverted Nanopyramid Arrays for Advanced Light Trapping in Crystalline Silicon Thin Film Solar Cells.

PubMed

Zhou, Suqiong; Yang, Zhenhai; Gao, Pingqi; Li, Xiaofeng; Yang, Xi; Wang, Dan; He, Jian; Ying, Zhiqin; Ye, Jichun

2016-12-01

Crystalline silicon thin film (c-Si TF) solar cells with an active layer thickness of a few micrometers may provide a viable pathway for further sustainable development of photovoltaic technology, because of its potentials in cost reduction and high efficiency. However, the performance of such cells is largely constrained by the deteriorated light absorption of the ultrathin photoactive material. Here, we report an efficient light-trapping strategy in c-Si TFs (~20 μm in thickness) that utilizes two-dimensional (2D) arrays of inverted nanopyramid (INP) as surface texturing. Three types of INP arrays with typical periodicities of 300, 670, and 1400 nm, either on front, rear, or both surfaces of the c-Si TFs, are fabricated by scalable colloidal lithography and anisotropic wet etch technique. With the extra aid of antireflection coating, the sufficient optical absorption of 20-μm-thick c-Si with a double-sided 1400-nm INP arrays yields a photocurrent density of 39.86 mA/cm(2), which is about 76 % higher than the flat counterpart (22.63 mA/cm(2)) and is only 3 % lower than the value of Lambertian limit (41.10 mA/cm(2)). The novel surface texturing scheme with 2D INP arrays has the advantages of excellent antireflection and light-trapping capabilities, an inherent low parasitic surface area, a negligible surface damage, and a good compatibility for subsequent process steps, making it a good alternative for high-performance c-Si TF solar cells.

Confidence set interference with a prior quadratic bound. [in geophysics

NASA Technical Reports Server (NTRS)

Backus, George E.

1989-01-01

Neyman's (1937) theory of confidence sets is developed as a replacement for Bayesian interference (BI) and stochastic inversion (SI) when the prior information is a hard quadratic bound. It is recommended that BI and SI be replaced by confidence set interference (CSI) only in certain circumstances. The geomagnetic problem is used to illustrate the general theory of CSI.

Charter Schools Indicators: A Report from the Center on Educational Governance University of Southern California. CSI-USC 2010

ERIC Educational Resources Information Center

Center on Educational Governance, 2010

2010-01-01

CSI-USC continues to make sense of what the California statewide data system provides. This fourth annual report gauges multiple measures of academic and financial performance, probing well beyond mere test scores. Ratings in familiar green, yellow, and red cover four areas: financial resources and investment, school quality, student performance…

Children and Crime Scenes: Have Schools Fallen Victim to the CSI Effect?

ERIC Educational Resources Information Center

Eskriett, Angela

2011-01-01

Whilst there continues to be debate regarding the influence of the "CSI effect" upon the criminal justice system, there appears to be a general consensus that the popularisation of work within the field, particularly through a number of "procedural cop shows", has fuelled an explosion in the number of young people choosing to pursue a career in…

The Capital Intensity of Photovoltaics Manufacturing

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

Basore, Paul

2015-10-19

Factory capital expenditure (capex) for photovoltaic (PV) module manufacturing strongly influences the per-unit cost of a c-Si module. This provides a significant opportunity to address the U.S. DOE SunShot module price target through capex innovation. Innovation options to reduce the capex of PV manufacturing include incremental and disruptive process innovation with c-Si, platform innovations, and financial approaches. and financial approaches.

FleCSPH - a parallel and distributed SPH implementation based on the FleCSI framework

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

Junghans, Christoph; Loiseau, Julien

2017-06-20

FleCSPH is a multi-physics compact application that exercises FleCSI parallel data structures for tree-based particle methods. In particular, FleCSPH implements a smoothed-particle hydrodynamics (SPH) solver for the solution of Lagrangian problems in astrophysics and cosmology. FleCSPH includes support for gravitational forces using the fast multipole method (FMM).

Advances in Energy Conservation of China Steel Industry

PubMed Central

Sun, Wenqiang; Cai, Jiuju; Ye, Zhu

2013-01-01

The course, technical progresses, and achievements of energy conservation of China steel industry (CSI) during 1980–2010 were summarized. Then, the paper adopted e-p method to analyze the variation law and influencing factors of energy consumptions of large- and medium-scale steel plants within different stages. It is pointed out that energy consumption per ton of crude steel has been almost one half lower in these thirty years, with 60% as direct energy conservation owing to the change of process energy consumption and 40% as indirect energy conservation attributed to the adjustment of production structure. Next, the latest research progress of some key common technologies in CSI was introduced. Also, the downtrend of energy consumption per ton of crude steel and the potential energy conservation for CSI during 2011–2025 were forecasted. Finally, it is indicated that the key topic of the next 15 years' research on the energy conservation of CSI is the synergistic operation of material flow and energy flow. It could be achieved by the comprehensive study on energy flow network optimization, such as production, allocation, utilization, recovery, reuse, and resource, according to the energy quantity, quality, and user demand following the first and second laws of thermodynamics. PMID:23533344

Tantalum oxide/silicon nitride: A negatively charged surface passivation stack for silicon solar cells

NASA Astrophysics Data System (ADS)

Wan, Yimao; Bullock, James; Cuevas, Andres

2015-05-01

This letter reports effective passivation of crystalline silicon (c-Si) surfaces by thermal atomic layer deposited tantalum oxide (Ta2O5) underneath plasma enhanced chemical vapour deposited silicon nitride (SiNx). Cross-sectional transmission electron microscopy imaging shows an approximately 2 nm thick interfacial layer between Ta2O5 and c-Si. Surface recombination velocities as low as 5.0 cm/s and 3.2 cm/s are attained on p-type 0.8 Ω.cm and n-type 1.0 Ω.cm c-Si wafers, respectively. Recombination current densities of 25 fA/cm2 and 68 fA/cm2 are measured on 150 Ω/sq boron-diffused p+ and 120 Ω/sq phosphorus-diffused n+ c-Si, respectively. Capacitance-voltage measurements reveal a negative fixed insulator charge density of -1.8 × 1012 cm-2 for the Ta2O5 film and -1.0 × 1012 cm-2 for the Ta2O5/SiNx stack. The Ta2O5/SiNx stack is demonstrated to be an excellent candidate for surface passivation of high efficiency silicon solar cells.

Advances in energy conservation of China steel industry.

PubMed

Sun, Wenqiang; Cai, Jiuju; Ye, Zhu

2013-01-01

The course, technical progresses, and achievements of energy conservation of China steel industry (CSI) during 1980-2010 were summarized. Then, the paper adopted e-p method to analyze the variation law and influencing factors of energy consumptions of large- and medium-scale steel plants within different stages. It is pointed out that energy consumption per ton of crude steel has been almost one half lower in these thirty years, with 60% as direct energy conservation owing to the change of process energy consumption and 40% as indirect energy conservation attributed to the adjustment of production structure. Next, the latest research progress of some key common technologies in CSI was introduced. Also, the downtrend of energy consumption per ton of crude steel and the potential energy conservation for CSI during 2011-2025 were forecasted. Finally, it is indicated that the key topic of the next 15 years' research on the energy conservation of CSI is the synergistic operation of material flow and energy flow. It could be achieved by the comprehensive study on energy flow network optimization, such as production, allocation, utilization, recovery, reuse, and resource, according to the energy quantity, quality, and user demand following the first and second laws of thermodynamics.

Environmental Stability and Oxidation Behavior of HfO2-Si and YbGd(O) Based Environmental Barrier Coating Systems for SiCSiC Ceramic Matrix Composites

NASA Technical Reports Server (NTRS)

Zhu, Dongming; Farmer, Serene; McCue, Terry R.; Harder, Bryan; Hurst, Janet B.

2017-01-01

Ceramic environmental barrier coatings (EBC) and SiCSiC ceramic matrix composites (CMCs) will play a crucial role in future aircraft propulsion systems because of their ability to significantly increase engine operating temperatures, improve component durability, reduce engine weight and cooling requirements. Advanced EBC systems for SiCSiC CMC turbine and combustor hot section components are currently being developed to meet future turbine engine emission and performance goals. One of the significant material development challenges for the high temperature CMC components is to develop prime-reliant, environmental durable environmental barrier coating systems. In this paper, the durability and performance of advanced Electron Beam-Physical Vapor Deposition (EB-PVD) NASA HfO2-Si and YbGdSi(O) EBC bond coat top coat systems for SiCSiC CMC have been summarized. The high temperature thermomechanical creep, fatigue and oxidation resistance have been investigated in the laboratory simulated high-heat-flux environmental test conditions. The advanced NASA EBC systems showed promise to achieve 1500C temperature capability, helping enable next generation turbine engines with significantly improved engine component temperature capability and durability.

Ftx is a non-coding RNA which affects Xist expression and chromatin structure within the X-inactivation center region.

PubMed

Chureau, Corinne; Chantalat, Sophie; Romito, Antonio; Galvani, Angélique; Duret, Laurent; Avner, Philip; Rougeulle, Claire

2011-02-15

X chromosome inactivation (XCI) is an essential epigenetic process which involves several non-coding RNAs (ncRNAs), including Xist, the master regulator of X-inactivation initiation. Xist is flanked in its 5' region by a large heterochromatic hotspot, which contains several transcription units including a gene of unknown function, Ftx (five prime to Xist). In this article, we describe the characterization and functional analysis of murine Ftx. We present evidence that Ftx produces a conserved functional long ncRNA, and additionally hosts microRNAs (miR) in its introns. Strikingly, Ftx partially escapes X-inactivation and is upregulated specifically in female ES cells at the onset of X-inactivation, an expression profile which closely follows that of Xist. We generated Ftx null ES cells to address the function of this gene. In these cells, only local changes in chromatin marks are detected within the hotspot, indicating that Ftx is not involved in the global maintenance of the heterochromatic structure of this region. The Ftx mutation, however, results in widespread alteration of transcript levels within the X-inactivation center (Xic) and particularly important decreases in Xist RNA levels, which were correlated with increased DNA methylation at the Xist CpG island. Altogether our results indicate that Ftx is a positive regulator of Xist and lead us to propose that Ftx is a novel ncRNA involved in XCI.

Silicon nitride equation of state

NASA Astrophysics Data System (ADS)

Brown, Robert C.; Swaminathan, Pazhayannur K.

2017-01-01

This report presents the development of a global, multi-phase equation of state (EOS) for the ceramic silicon nitride (Si3N4).1 Structural forms include amorphous silicon nitride normally used as a thin film and three crystalline polymorphs. Crystalline phases include hexagonal α-Si3N4, hexagonal β-Si3N4, and the cubic spinel c-Si3N4. Decomposition at about 1900 °C results in a liquid silicon phase and gas phase products such as molecular nitrogen, atomic nitrogen, and atomic silicon. The silicon nitride EOS was developed using EOSPro which is a new and extended version of the PANDA II code. Both codes are valuable tools and have been used successfully for a variety of material classes. Both PANDA II and EOSPro can generate a tabular EOS that can be used in conjunction with hydrocodes. The paper describes the development efforts for the component solid phases and presents results obtained using the EOSPro phase transition model to investigate the solid-solid phase transitions in relation to the available shock data that have indicated a complex and slow time dependent phase change to the c-Si3N4 phase. Furthermore, the EOSPro mixture model is used to develop a model for the decomposition products; however, the need for a kinetic approach is suggested to combine with the single component solid models to simulate and further investigate the global phase coexistences.

Initial steps of inactivation at the K+ channel selectivity filter

PubMed Central

Thomson, Andrew S.; Heer, Florian T.; Smith, Frank J.; Hendron, Eunan; Bernèche, Simon; Rothberg, Brad S.

2014-01-01

K+ efflux through K+ channels can be controlled by C-type inactivation, which is thought to arise from a conformational change near the channel’s selectivity filter. Inactivation is modulated by ion binding near the selectivity filter; however, the molecular forces that initiate inactivation remain unclear. We probe these driving forces by electrophysiology and molecular simulation of MthK, a prototypical K+ channel. Either Mg2+ or Ca2+ can reduce K+ efflux through MthK channels. However, Ca2+, but not Mg2+, can enhance entry to the inactivated state. Molecular simulations illustrate that, in the MthK pore, Ca2+ ions can partially dehydrate, enabling selective accessibility of Ca2+ to a site at the entry to the selectivity filter. Ca2+ binding at the site interacts with K+ ions in the selectivity filter, facilitating a conformational change within the filter and subsequent inactivation. These results support an ionic mechanism that precedes changes in channel conformation to initiate inactivation. PMID:24733889

Wet-chemical passivation of atomically flat and structured silicon substrates for solar cell application

NASA Astrophysics Data System (ADS)

Angermann, H.; Rappich, J.; Korte, L.; Sieber, I.; Conrad, E.; Schmidt, M.; Hübener, K.; Polte, J.; Hauschild, J.

2008-04-01

Special sequences of wet-chemical oxidation and etching steps were optimised with respect to the etching behaviour of differently oriented silicon to prepare very smooth silicon interfaces with excellent electronic properties on mono- and poly-crystalline substrates. Surface photovoltage (SPV) and photoluminescence (PL) measurements, atomic force microscopy (AFM) and scanning electron microscopy (SEM) investigations were utilised to develop wet-chemical smoothing procedures for atomically flat and structured surfaces, respectively. Hydrogen-termination as well as passivation by wet-chemical oxides were used to inhibit surface contamination and native oxidation during the technological processing. Compared to conventional pre-treatments, significantly lower micro-roughness and densities of surface states were achieved on mono-crystalline Si(100), on evenly distributed atomic steps, such as on vicinal Si(111), on silicon wafers with randomly distributed upside pyramids, and on poly-crystalline EFG ( Edge-defined Film-fed- Growth) silicon substrates. The recombination loss at a-Si:H/c-Si interfaces prepared on c-Si substrates with randomly distributed upside pyramids was markedly reduced by an optimised wet-chemical smoothing procedure, as determined by PL measurements. For amorphous-crystalline hetero-junction solar cells (ZnO/a-Si:H(n)/c-Si(p)/Al) with textured c-Si substrates the smoothening procedure results in a significant increase of short circuit current Isc, fill factor and efficiency η. The scatter in the cell parameters for measurements on different cells is much narrower, as compared to conventional pre-treatments, indicating more well-defined and reproducible surface conditions prior to a-Si:H emitter deposition and/or a higher stability of the c-Si surface against variations in the a-Si:H deposition conditions.

Enhanced fast-inactivated state stability of cardiac sodium channels by a novel voltage sensor SCN5A mutation, R1632C, as a cause of atypical Brugada syndrome.

PubMed

Nakajima, Tadashi; Kaneko, Yoshiaki; Saito, Akihiro; Ota, Masaki; Iijima, Takafumi; Kurabayashi, Masahiko

2015-11-01

Mutations in SCN5A, which encodes the cardiac voltage-gated sodium channels, can be associated with multiple electrophysiological phenotypes. A novel SCN5A R1632C mutation, located in the domain IV-segment 4 voltage sensor, was identified in a young male patient who had a syncopal episode during exercise and presented with atrial tachycardia, sinus node dysfunction, and Brugada syndrome. We sought to elucidate the functional consequences of the R1632C mutation. The wild-type (WT) or R1632C SCN5A mutation was coexpressed with β1 subunit in tsA201 cells, and whole-cell sodium currents (INa) were recorded using patch-clamp methods. INa density, measured at -20 mV from a holding potential of -120 mV, for R1632C was significantly lower than that for WT (R1632C: -433 ± 52 pA/pF, n = 14; WT: -672 ± 90 pA/pF, n = 15; P < .05); however, no significant changes were observed in the steady-state activation and fast inactivation rate. The steady-state inactivation curve for R1632C was remarkably shifted to hyperpolarizing potentials compared with that for WT (R1632C: V1/2 = -110.7 ± 0.8 mV, n = 16; WT: V1/2 = -85.9 ± 2.5 mV, n = 17; P < .01). The steady-state fast inactivation curve for R1632C was also shifted to the same degree. Recovery from fast inactivation after a 20-ms depolarizing pulse for R1632C was remarkably delayed compared with that for WT (R1632C: τ = 246.7 ± 14.3 ms, n = 8; WT: τ = 3.7 ± 0.3 ms, n = 8; P < .01). Repetitive depolarizing pulses at various cycle lengths greatly attenuated INa for R1632C than that for WT. R1632C showed a loss of function of INa by an enhanced fast-inactivated state stability because of a pronounced impairment of recovery from fast inactivation, which may explain the phenotypic manifestation observed in our patient. Copyright © 2015 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Multifractal detrended cross-correlations between the CSI 300 index futures and the spot markets based on high-frequency data

NASA Astrophysics Data System (ADS)

Cao, Guangxi; Han, Yan; Cui, Weijun; Guo, Yu

2014-11-01

The cross-correlation between the China Securities Index 300 (CSI 300) index futures and the spot markets based on high-frequency data is discussed in this paper. We empirically analyze the cross-correlation by using the multifractal detrended cross-correlation analysis (MF-DCCA), and investigate further the characteristics of asymmetry, frequency difference, and transmission direction of the cross-correlation. The results indicate that the cross-correlation between the two markets is significant and multifractal. Meanwhile, weak asymmetries exist in the cross-correlation, and higher data frequency results in a lower multifractality degree of the cross-correlation. The causal relationship between the two markets is bidirectional, but the CSI 300 index futures market has greater impact on the spot market.

Controls-structures interaction guest investigator program: Overview and phase 1 experimental results and future plans

NASA Technical Reports Server (NTRS)

Smith-Taylor, Rudeen; Tanner, Sharon E.

1993-01-01

The NASA Controls-Structures Interaction (CSI) Guest Investigator program is described in terms of its support of the development of CSI technologies. The program is based on the introduction of CSI researchers from industry and academia to available test facilities for experimental validation of technologies and methods. Phase 1 experimental results are reviewed with attention given to their use of the Mini-MAST test facility and the facility for the Advance Control Evaluation of Structures. Experiments were conducted regarding the following topics: collocated/noncollocated controllers, nonlinear math modeling, controller design, passive/active suspension systems design, and system identification and fault isolation. The results demonstrate that significantly enhanced performance from the control techniques can be achieved by integrating knowledge of the structural dynamics under consideration into the approaches.

Diffractive intermediate layer enables broadband light trapping for high efficiency ultrathin c-Si tandem cells

NASA Astrophysics Data System (ADS)

Li, Guijun; Ho, Jacob Y. L.; Li, He; Kwok, Hoi-Sing

2014-06-01

Light management through the intermediate reflector in the tandem cell configuration is of great practical importance for achieving high stable efficiency and also low cost production. So far, however, the intermediate reflectors employed currently are mainly focused on the light absorption enhancement of the top cell. Here, we present a diffractive intermediate layer that allows for light trapping over a broadband wavelength for the ultrathin c-Si tandem solar cell. Compared with the standard intermediate reflector, this nanoscale architectural intermediate layer results in a 35% and 21% remarkable enhancement of the light absorption in the top (400-800 nm) and bottom (800-1100 nm) cells simultaneously, and ultrathin c-Si tandem cells with impressive conversion efficiency of 13.3% are made on the glass substrate.

Cubic spline interpolation with overlapped window and data reuse for on-line Hilbert Huang transform biomedical microprocessor.

PubMed

Chang, Nai-Fu; Chiang, Cheng-Yi; Chen, Tung-Chien; Chen, Liang-Gee

2011-01-01

On-chip implementation of Hilbert-Huang transform (HHT) has great impact to analyze the non-linear and non-stationary biomedical signals on wearable or implantable sensors for the real-time applications. Cubic spline interpolation (CSI) consumes the most computation in HHT, and is the key component for the HHT processor. In tradition, CSI in HHT is usually performed after the collection of a large window of signals, and the long latency violates the realtime requirement of the applications. In this work, we propose to keep processing the incoming signals on-line with small and overlapped data windows without sacrificing the interpolation accuracy. 58% multiplication and 73% division of CSI are saved after the data reuse between the data windows.

A Study of the quality of CsI detectors and pulse-shape discrimination of scintillators for ?[U+0251]-particles, ?[U+0263]-particles, and neutrons

NASA Astrophysics Data System (ADS)

Salyer, Kaitlin; Rogachev, Grigory; Hooker, Joshua

2016-09-01

This project studied the capabilities of two different scintillators, Cesium Iodide (CsI) and p-Terphenyl. First, the resolution of a CsI detector was investigated by exposing only very small areas of its surface at a time to an alpha source. Second, the abilities of p-Terphenyl to detect alpha particles, gamma particles, and neutrons were analyzed through pulse shape discrimination. p-Terphenyl is of particular interest because it will be used in the Mitchell Institute Neutrino Experiment at Reactor (MINER) at Texas A&M University for measuring background data. The information learned from conducting these tests will be useful in understanding and expanding the limits of the experiments in which these detectors will ultimately be used.

Log-periodic view on critical dates of the Chinese stock market bubbles

NASA Astrophysics Data System (ADS)

Li, Chong

2017-01-01

We present an analysis of critical dates of three historical Chinese stock market bubbles (July 2006-Oct. 2007, Dec. 2007-Oct. 2008, Oct. 2014-June 2015) based on the Shanghai Shenzhen CSI 300 index (CSI300). This supports that the log-periodic power law singularity (LPPLS) model can describe well the behavior of super-exponential (power law with finite-time singularity) increase or decrease of the CSI300 index, suggesting that the LPPLS is available to predict the critical date. We also attempt to analyze the fitting parameter α of the LPPLS and the forecast gap which is between the last observed date and the expected critical date, proposing that the forecast gap is an alternative way for advanced warning of the market conversion.

Hydrophobic interactions between the voltage sensor and pore mediate inactivation in Kv11.1 channels

PubMed Central

Perry, Matthew D.; Wong, Sophia; Ng, Chai Ann

2013-01-01

Kv11.1 channels are critical for the maintenance of a normal heart rhythm. The flow of potassium ions through these channels is controlled by two voltage-regulated gates, termed “activation” and “inactivation,” located at opposite ends of the pore. Crucially in Kv11.1 channels, inactivation gating occurs much more rapidly, and over a distinct range of voltages, compared with activation gating. Although it is clear that the fourth transmembrane segments (S4), within each subunit of the tetrameric channel, are important for controlling the opening and closing of the activation gate, their role during inactivation gating is much less clear. Here, we use rate equilibrium free energy relationship (REFER) analysis to probe the contribution of the S4 “voltage-sensor” helix during inactivation of Kv11.1 channels. Contrary to the important role that charged residues play during activation gating, it is the hydrophobic residues (Leu529, Leu530, Leu532, and Val535) that are the key molecular determinants of inactivation gating. Within the context of an interconnected multi-domain model of Kv11.1 inactivation gating, our REFER analysis indicates that the S4 helix and the S4–S5 linker undergo a conformational rearrangement shortly after that of the S5 helix and S5P linker, but before the S6 helix. Combining REFER analysis with double mutant cycle analysis, we provide evidence for a hydrophobic interaction between residues on the S4 and S5 helices. Based on a Kv11.1 channel homology model, we propose that this hydrophobic interaction forms the basis of an intersubunit coupling between the voltage sensor and pore domain that is an important mediator of inactivation gating. PMID:23980196

Evidence against an X-linked visual loss susceptibility locus in Leber hereditary optic neuropathy

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

Chalmers, R.M.; Davis, M.B.; Sweeney, M.G.

1996-07-01

Pedigree analysis of British families with Leber hereditary optic neuropathy (LHON) closely fits a model in which a pathogenic mtDNA mutation interacts with an X-linked visual loss susceptibility locus (VLSL). This model predicts that 60% of affected females will show marked skewing of X inactivation. Linkage analysis in British and Italian families with genetically proven LHON has excluded the presence of such a VLSL over 169 cM of the X chromosome both when all families were analyzed together and when only families with the bp 11778 mutation were studied. Further, there was no excess skewing of X inactivation in affectedmore » females. There was no evidence for close linkage to three markers in the pseudoautosomal region of the sex chromosomes. The mechanism of incomplete penetrance and male predominance in LHON remains unclear. 27 refs., 1 fig., 3 tabs.« less

Metastability of a-SiOx:H thin films for c-Si surface passivation

NASA Astrophysics Data System (ADS)

Serenelli, L.; Martini, L.; Imbimbo, L.; Asquini, R.; Menchini, F.; Izzi, M.; Tucci, M.

2017-01-01

The adoption of a-SiOx:H films obtained by PECVD in heterojunction solar cells is a key to further increase their efficiency, because of its transparency in the UV with respect to the commonly used a-Si:H. At the same time this layer must guarantee high surface passivation of the c-Si to be suitable in high efficiency solar cell manufacturing. On the other hand the application of amorphous materials like a-Si:H and SiNx on the cell frontside expose them to the mostly energetic part of the sun spectrum, leading to a metastability of their passivation properties. Moreover as for amorphous silicon, thermal annealing procedures are considered as valuable steps to enhance and stabilize thin film properties, when performed at opportune temperature. In this work we explored the reliability of a-SiOx:H thin film layers surface passivation on c-Si substrates under UV exposition, in combination with thermal annealing steps. Both p- and n-type doped c-Si substrates were considered. To understand the effect of UV light soaking we monitored the minority carriers lifetime and Sisbnd H and Sisbnd O bonding, by FTIR spectra, after different exposure times to light coming from a deuterium lamp, filtered to UV-A region, and focused on the sample to obtain a power density of 50 μW/cm2. We found a certain lifetime decrease after UV light soaking in both p- and n-type c-Si passivated wafers according to a a-SiOx:H/c-Si/a-SiOx:H structure. The role of a thermal annealing, which usually enhances the as-deposited SiOx passivation properties, was furthermore considered. In particular we monitored the UV light soaking effect on c-Si wafers after a-SiOx:H coating by PECVD and after a thermal annealing treatment at 300 °C for 30 min, having selected these conditions on the basis of the study of the effect due to different temperatures and durations. We correlated the lifetime evolution and the metastability effect of thermal annealing to the a-SiOx:H/c-Si interface considering the evolution of hydrogen in the film revealed by FTIR spectra, and we developed a model for the effect of both treatments on the Sisbnd H bonding and the metastability shown in the lifetime of a-SiOx:H/c-Si/a-SiOx:H structure. We found that, after UV exposure, thermal annealing steps can be used as a tool for the c-Si passivation recovery and enhancement.

Carrier transport and sensitivity issues in heterojunction with intrinsic thin layer solar cells on N-type crystalline silicon: A computer simulation study

NASA Astrophysics Data System (ADS)

Rahmouni, M.; Datta, A.; Chatterjee, P.; Damon-Lacoste, J.; Ballif, C.; Roca i Cabarrocas, P.

2010-03-01

Heterojunction with intrinsic thin layer or "HIT" solar cells are considered favorable for large-scale manufacturing of solar modules, as they combine the high efficiency of crystalline silicon (c-Si) solar cells, with the low cost of amorphous silicon technology. In this article, based on experimental data published by Sanyo, we simulate the performance of a series of HIT cells on N-type crystalline silicon substrates with hydrogenated amorphous silicon (a-Si:H) emitter layers, to gain insight into carrier transport and the general functioning of these devices. Both single and double HIT structures are modeled, beginning with the initial Sanyo cells having low open circuit voltages but high fill factors, right up to double HIT cells exhibiting record values for both parameters. The one-dimensional numerical modeling program "Amorphous Semiconductor Device Modeling Program" has been used for this purpose. We show that the simulations can correctly reproduce the electrical characteristics and temperature dependence for a set of devices with varying I-layer thickness. Under standard AM1.5 illumination, we show that the transport is dominated by the diffusion mechanism, similar to conventional P/N homojunction solar cells, and tunneling is not required to describe the performance of state-of-the art devices. Also modeling has been used to study the sensitivity of N-c-Si HIT solar cell performance to various parameters. We find that the solar cell output is particularly sensitive to the defect states on the surface of the c-Si wafer facing the emitter, to the indium tin oxide/P-a-Si:H front contact barrier height and to the band gap and activation energy of the P-a-Si:H emitter, while the I-a-Si:H layer is necessary to achieve both high Voc and fill factor, as it passivates the defects on the surface of the c-Si wafer. Finally, we describe in detail for most parameters how they affect current transport and cell properties.

Block of human cardiac sodium channels by lacosamide: evidence for slow drug binding along the activation pathway.

PubMed

Wang, Ging Kuo; Wang, Sho-Ya

2014-05-01

Lacosamide is an anticonvulsant hypothesized to enhance slow inactivation of neuronal Na(+) channels for its therapeutic action. Cardiac Na(+) channels display less and incomplete slow inactivation, but their sensitivity toward lacosamide remains unknown. We therefore investigated the action of lacosamide in human cardiac Nav1.5 and Nav1.5-CW inactivation-deficient Na(+) channels. Lacosamide showed little effect on hNav1.5 Na(+) currents at 300 µM when cells were held at -140 mV. With 30-second conditioning pulses from -90 to -50 mV; however, hNav1.5 Na(+) channels became sensitive to lacosamide with IC50 (50% inhibitory concentration) around 70-80 µM. Higher IC50 values were found at -110 and -30 mV. The development of lacosamide block at -70 mV was slow in wild-type Na(+) channels (τ; 8.04 ± 0.39 seconds, n = 8). This time constant was significantly accelerated in hNav1.5-CW inactivation-deficient counterparts. The recovery from lacosamide block at -70 mV for 10 seconds was relatively rapid in wild-type Na(+) channels (τ; 639 ± 90 milliseconds, n = 8). This recovery was accelerated further in hNav1.5-CW counterparts. Unexpectedly, lacosamide elicited a time-dependent block of persistent hNav1.5-CW Na(+) currents with an IC50 of 242 ± 19 µM (n = 5). Furthermore, both hNav1.5-CW/F1760K mutant and batrachotoxin-activated hNav1.5 Na(+) channels became completely lacosamide resistant, indicating that the lacosamide receptor overlaps receptors for local anesthetics and batrachotoxin. Our results together suggest that lacosamide targets the intermediate preopen and open states of hNav1.5 Na(+) channels. Lacosamide may thus track closely the conformational changes at the hNav1.5-F1760 region along the activation pathway.

Block of Human Cardiac Sodium Channels by Lacosamide: Evidence for Slow Drug Binding along the Activation Pathway

PubMed Central

Wang, Sho-Ya

2014-01-01

Lacosamide is an anticonvulsant hypothesized to enhance slow inactivation of neuronal Na+ channels for its therapeutic action. Cardiac Na+ channels display less and incomplete slow inactivation, but their sensitivity toward lacosamide remains unknown. We therefore investigated the action of lacosamide in human cardiac Nav1.5 and Nav1.5-CW inactivation-deficient Na+ channels. Lacosamide showed little effect on hNav1.5 Na+ currents at 300 µM when cells were held at −140 mV. With 30-second conditioning pulses from −90 to −50 mV; however, hNav1.5 Na+ channels became sensitive to lacosamide with IC50 (50% inhibitory concentration) around 70–80 µM. Higher IC50 values were found at −110 and −30 mV. The development of lacosamide block at −70 mV was slow in wild-type Na+ channels (τ; 8.04 ± 0.39 seconds, n = 8). This time constant was significantly accelerated in hNav1.5-CW inactivation-deficient counterparts. The recovery from lacosamide block at −70 mV for 10 seconds was relatively rapid in wild-type Na+ channels (τ; 639 ± 90 milliseconds, n = 8). This recovery was accelerated further in hNav1.5-CW counterparts. Unexpectedly, lacosamide elicited a time-dependent block of persistent hNav1.5-CW Na+ currents with an IC50 of 242 ± 19 µM (n = 5). Furthermore, both hNav1.5-CW/F1760K mutant and batrachotoxin-activated hNav1.5 Na+ channels became completely lacosamide resistant, indicating that the lacosamide receptor overlaps receptors for local anesthetics and batrachotoxin. Our results together suggest that lacosamide targets the intermediate preopen and open states of hNav1.5 Na+ channels. Lacosamide may thus track closely the conformational changes at the hNav1.5-F1760 region along the activation pathway. PMID:24563546

Response to Intervention and Continuous School Improvement: Using Data, Vision, and Leadership to Design, Implement, and Evaluate a Schoolwide Prevention System

ERIC Educational Resources Information Center

Bernhardt, Victoria L.; Hebert, Connie L.

2011-01-01

Ensure the success of your school and improve the learning of "all" students by implementing Response-to-Intervention (RTI) as part of a continuous school improvement (CSI) process. This book shows you how to get your entire staff working together to design, implement, and evaluate a schoolwide prevention system. With specific examples, CSI expert…

New Forensics Methods Looking More Like CSI: Rapid DNA Analysis, Proteomics, and New Technology Increasingly Impact Forensics Investigations.

PubMed

Mertz, Leslie

2017-01-01

If CSI and those other police procedural TV shows are to be believed, criminals don't have a chance. A finger smudge on a light switch, a flake of skin, or a sweat-stained fiber is all the information an investigator needs to positively identify the perpetrator and put him or her behind bars.

CSI-Chocolate Science Investigation and the Case of the Recipe Rip-Off: Using an Extended Problem-Based Scenario to Enhance High School Students' Science Engagement

ERIC Educational Resources Information Center

Marle, Peter D.; Decker, Lisa; Taylor, Victoria; Fitzpatrick, Kathleen; Khaliqi, David; Owens, Janel E.; Henry, Renee M.

2014-01-01

This paper discusses a K-12/university collaboration in which students participated in a four-day scenario-based summer STEM (science, technology, engineering, and mathematics) camp aimed at making difficult scientific concepts salient. This scenario, Jumpstart STEM-CSI: Chocolate Science Investigation (JSCSI), used open- and guided-inquiry…

Capsid functions of inactivated human picornaviruses and feline calicivirus.

PubMed

Nuanualsuwan, Suphachai; Cliver, Dean O

2003-01-01

The exceptional stability of enteric viruses probably resides in their capsids. The capsid functions of inactivated human picornaviruses and feline calicivirus (FCV) were determined. Viruses were inactivated by UV, hypochlorite, high temperature (72 degrees C), and physiological temperature (37 degrees C), all of which are pertinent to transmission via food and water. Poliovirus (PV) and hepatitis A virus (HAV) are transmissible via water and food, and FCV is the best available surrogate for the Norwalk-like viruses, which are leading causes of food-borne and waterborne disease in the United States. The capsids of all 37 degrees C-inactivated viruses still protected the viral RNA against RNase, even in the presence of proteinase K, which contrasted with findings with viruses inactivated at 72 degrees C. The loss of ability of the virus to attach to homologous cell receptors was universal, regardless of virus type and inactivation method, except for UV-inactivated HAV, and so virus inactivation was almost always accompanied by the loss of virus attachment. Inactivated HAV and FCV were captured by homologous antibodies. However, inactivated PV type 1 (PV-1) was not captured by homologous antibody and 37 degrees C-inactivated PV-1 was only partially captured. The epitopes on the capsids of HAV and FCV are evidently discrete from the receptor attachment sites, unlike those of PV-1. These findings indicate that the primary target of UV, hypochlorite, and 72 degrees C inactivation is the capsid and that the target of thermal inactivation (37 degrees C versus 72 degrees C) is temperature dependent.

Urease from Helicobacter pylori is inactivated by sulforaphane and other isothiocyanates.

PubMed

Fahey, Jed W; Stephenson, Katherine K; Wade, Kristina L; Talalay, Paul

2013-05-24

Infections by Helicobacter pylori are very common, causing gastroduodenal inflammation including peptic ulcers, and increasing the risk of gastric neoplasia. The isothiocyanate (ITC) sulforaphane [SF; 1-isothiocyanato-4-(methylsulfinyl)butane] derived from edible crucifers such as broccoli is potently bactericidal against Helicobacter, including antibiotic-resistant strains, suggesting a possible dietary therapy. Gastric H. pylori infections express high urease activity which generates ammonia, neutralizes gastric acidity, and promotes inflammation. The finding that SF inhibits (inactivates) urease (jack bean and Helicobacter) raised the issue of whether these properties might be functionally related. The rates of inactivation of urease activity depend on enzyme and SF concentrations and show first order kinetics. Treatment with SF results in time-dependent increases in the ultraviolet absorption of partially purified Helicobacter urease in the 260-320 nm region. This provides direct spectroscopic evidence for the formation of dithiocarbamates between the ITC group of SF and cysteine thiols of urease. The potencies of inactivation of Helicobacter urease by isothiocyanates structurally related to SF were surprisingly variable. Natural isothiocyanates closely related to SF, previously shown to be bactericidal (berteroin, hirsutin, phenethyl isothiocyanate, alyssin, and erucin), did not inactivate urease activity. Furthermore, SF is bactericidal against both urease positive and negative H. pylori strains. In contrast, some isothiocyanates such as benzoyl-ITC, are very potent urease inactivators, but are not bactericidal. The bactericidal effects of SF and other ITC against Helicobacter are therefore not obligatorily linked to urease inactivation, but may reduce the inflammatory component of Helicobacter infections. Copyright © 2013 Elsevier Inc. All rights reserved.

Spread of X-chromosome inactivation into autosomal sequences: role for DNA elements, chromatin features and chromosomal domains

PubMed Central

Cotton, Allison M.; Chen, Chih-Yu; Lam, Lucia L.; Wasserman, Wyeth W.; Kobor, Michael S.; Brown, Carolyn J.

2014-01-01

X-chromosome inactivation results in dosage equivalence between the X chromosome in males and females; however, over 15% of human X-linked genes escape silencing and these genes are enriched on the evolutionarily younger short arm of the X chromosome. The spread of inactivation onto translocated autosomal material allows the study of inactivation without the confounding evolutionary history of the X chromosome. The heterogeneity and reduced extent of silencing on autosomes are evidence for the importance of DNA elements underlying the spread of silencing. We have assessed DNA methylation in six unbalanced X-autosome translocations using the Illumina Infinium HumanMethylation450 array. Two to 42% of translocated autosomal genes showed this mark of silencing, with the highest degree of inactivation observed for trisomic autosomal regions. Generally, the extent of silencing was greatest close to the translocation breakpoint; however, silencing was detected well over 100 kb into the autosomal DNA. Alu elements were found to be enriched at autosomal genes that escaped from inactivation while L1s were enriched at subject genes. In cells without the translocation, there was enrichment of heterochromatic features such as EZH2 and H3K27me3 for those genes that become silenced when translocated, suggesting that underlying chromatin structure predisposes genes towards silencing. Additionally, the analysis of topological domains indicated physical clustering of autosomal genes of common inactivation status. Overall, our analysis indicated a complex interaction between DNA sequence, chromatin features and the three-dimensional structure of the chromosome. PMID:24158853

Inactivation kinetics and steady-state current noise in the anomalous rectifier of tunicate egg cell membranes.

PubMed Central

Ohmori, H

1978-01-01

1. Inward K current through the anomalous rectifier in the tunicate egg (Halocynthis roretzi, Drashe) was studied under voltage clamp. The transient inward current in response to a step change of membrane potential was measured. The steady-state current fluctuations were analysed using the power density spectrum (p.d.s.). 2. The inward current showed time-dependent changes, which were described by a pair of the first order kinetic parameters, n and s for activation and inactivation, respectively. The steady-state channel open probability due to the activation process (n infinity) was assumed to be 1.0 for V more negative than about--100 mV, but that of the inactivation process (s infinity) and the time constant of inactivation (taus) were membrane potential dependent in the same potential range; both decreased with increasing hyperpolarization. 3. The inward currents in Na-free choline medium did not inactivate, but were decreased in size. In Na-free Li medium, inactivation was very small; the steady-state conductance was not affected significantly. 4. After exposure to high Ca media, an increase of the conductance was observed. This effect is probably caused by an increase of intracellular Ca due to Ca ions entering through the Na channels. Mg ions slightly decreased the conductance. 5. In the hyperpolarized membrane (-160 less than or equal to V less than or equal to -80mV), steady-state current noise was recorded and analysed using p.d.s. A p.d.s. of the 1/[1 + (f/fc)2] type as well a p.d.s. of the 1/f type was observed; f, frequency, fc, cut-off frequency. 6. fc was translated into time constant tauN (= 1/2pIfC) and compared with the time constant of inactivation, taus. There was a significant correlation betwen these values with a regression coefficient of 0.82. 7. Changing from 400 mM-Li abloshied inactivation and changed the p.d.s. from the 1/[1 + (f/fc)2] into the 1/f type. These results (paragraphs 5--7)suggest that the fluctuations in the steady-state currents originatte in the inactivation gatin kinetics of the an ofthe anomalous rectifier. 8. The number of anomalous rectifier channels and the unit channel conductance were estimated from the 1/[1 + (f/fc)2] type current noise according to the formula : (see text), where I infinity = gamma Nninfinity s infinity (V--VK), gamma the unit channel conductance, N the maximum number of channels that can be opened by a hyperpolarizing pulse per egg. The unit conductance was 6 pmho in standard artificial sea water and the channel density was 0.028/micrometer2. 9. The unit channel conductance (gamma) was dependent upon external K concentration, but the number ofchannels (N) was not. 10. The increase in chord conductance evoked by higher Ca concentrations was due to the increase of the channel number. By contrast, Mg ions seem to decrease the unit channel conductance slightly. PMID:568176

Chemical substitutions in the selectivity filter of potassium channels do not rule out constricted-like conformations for C-type inactivation

PubMed Central

Li, Jing; Boulanger, Eliot; Rui, Huan; Perozo, Eduardo; Roux, Benoît

2017-01-01

In many K+ channels, prolonged activating stimuli lead to a time-dependent reduction in ion conduction, a phenomenon known as C-type inactivation. X-ray structures of the KcsA channel suggest that this inactivated state corresponds to a “constricted” conformation of the selectivity filter. However, the functional significance of the constricted conformation has become a matter of debate. Functional and structural studies based on chemically modified semisynthetic KcsA channels along the selectivity filter led to the conclusion that the constricted conformation does not correspond to the C-type inactivated state. The main results supporting this view include the observation that C-type inactivation is not suppressed by a substitution of D-alanine at Gly77, even though this modification is believed to lock the selectivity filter into its conductive conformation, whereas it is suppressed following amide-to-ester backbone substitutions at Gly77 and Tyr78, even though these structure-conserving modifications are not believed to prevent the selectivity filter from adopting the constricted conformation. However, several untested assumptions about the structural and functional impact of these chemical modifications underlie these arguments. To make progress, molecular dynamics simulations based on atomic models of the KcsA channel were performed. The computational results support the notion that the constricted conformation of the selectivity filter corresponds to the functional C-type inactivated state of the KcsA. Importantly, MD simulations reveal that the semisynthetic KcsAD-ala77 channel can adopt an asymmetrical constricted-like nonconductive conformation and that the amide-to-ester backbone substitutions at Gly77 and Tyr78 perturb the hydrogen bonding involving the buried water molecules stabilizing the constricted conformation. PMID:28973956

The voltage sensor of excitation–contraction coupling in mammals: Inactivation and interaction with Ca2+

PubMed Central

2017-01-01

In skeletal muscle, the four-helix voltage-sensing modules (VSMs) of CaV1.1 calcium channels simultaneously gate two Ca2+ pathways: the CaV1.1 pore itself and the RyR1 calcium release channel in the sarcoplasmic reticulum. Here, to gain insight into the mechanism by which VSMs gate RyR1, we quantify intramembrane charge movement associated with VSM activation (sensing current) and gated Ca2+ release flux in single muscle cells of mice and rats. As found for most four-helix VSMs, upon sustained depolarization, rodent VSMs lose the ability to activate Ca2+ release channels opening; their properties change from a functionally capable mode, in which the mobile sensor charge is called charge 1, to an inactivated mode, charge 2, with a voltage dependence shifted toward more negative voltages. We find that charge 2 is promoted and Ca2+ release inactivated when resting, well-polarized muscle cells are exposed to low extracellular [Ca2+] and that the opposite occurs in high [Ca2+]. It follows that murine VSMs are partly inactivated at rest, which establishes the reduced availability of voltage sensing as a pathogenic mechanism in disorders of calcemia. We additionally find that the degree of resting inactivation is significantly different in two mouse strains, which underscores the variability of voltage sensor properties and their vulnerability to environmental conditions. Our studies reveal that the resting and activated states of VSMs are equally favored by extracellular Ca2+. Promotion by an extracellular species of two states of the VSM that differ in the conformation of the activation gate requires the existence of a second gate, inactivation, topologically extracellular and therefore accessible from outside regardless of the activation state. PMID:29021148

Bone regeneration in 3D printing bioactive ceramic scaffolds with improved tissue/material interface pore architecture in thin-wall bone defect.

PubMed

Shao, Huifeng; Ke, Xiurong; Liu, An; Sun, Miao; He, Yong; Yang, Xianyan; Fu, Jianzhong; Liu, Yanming; Zhang, Lei; Yang, Guojing; Xu, Sanzhong; Gou, Zhongru

2017-04-12

Three-dimensional (3D) printing bioactive ceramics have demonstrated alternative approaches to bone tissue repair, but an optimized materials system for improving the recruitment of host osteogenic cells into the bone defect and enhancing targeted repair of the thin-wall craniomaxillofacial defects remains elusive. Herein we systematically evaluated the role of side-wall pore architecture in the direct-ink-writing bioceramic scaffolds on mechanical properties and osteogenic capacity in rabbit calvarial defects. The pure calcium silicate (CSi) and dilute Mg-doped CSi (CSi-Mg6) scaffolds with different layer thickness and macropore sizes were prepared by varying the layer deposition mode from single-layer printing (SLP) to double-layer printing (DLP) and then by undergoing one-, or two-step sintering. It was found that the dilute Mg doping and/or two-step sintering schedule was especially beneficial for improving the compressive strength (∼25-104 MPa) and flexural strength (∼6-18 MPa) of the Ca-silicate scaffolds. The histological analysis for the calvarial bone specimens in vivo revealed that the SLP scaffolds had a high osteoconduction at the early stage (4 weeks) but the DLP scaffolds displayed a higher osteogenic capacity for a long time stage (8-12 weeks). Although the DLP CSi scaffolds displayed somewhat higher osteogenic capacity at 8 and 12 weeks, the DLP CSi-Mg6 scaffolds with excellent fracture resistance also showed appreciable new bone tissue ingrowth. These findings demonstrate that the side-wall pore architecture in 3D printed bioceramic scaffolds is required to optimize for bone repair in calvarial bone defects, and especially the Mg doping wollastontie is promising for 3D printing thin-wall porous scaffolds for craniomaxillofacial bone defect treatment.

Neural Mechanisms Underlying the Cost of Task Switching: An ERP Study

PubMed Central

Li, Ling; Wang, Meng; Zhao, Qian-Jing; Fogelson, Noa

2012-01-01

Background When switching from one task to a new one, reaction times are prolonged. This phenomenon is called switch cost (SC). Researchers have recently used several kinds of task-switching paradigms to uncover neural mechanisms underlying the SC. Task-set reconfiguration and passive dissipation of a previously relevant task-set have been reported to contribute to the cost of task switching. Methodology/Principal Findings An unpredictable cued task-switching paradigm was used, during which subjects were instructed to switch between a color and an orientation discrimination task. Electroencephalography (EEG) and behavioral measures were recorded in 14 subjects. Response-stimulus interval (RSI) and cue-stimulus interval (CSI) were manipulated with short and long intervals, respectively. Switch trials delayed reaction times (RTs) and increased error rates compared with repeat trials. The SC of RTs was smaller in the long CSI condition. For cue-locked waveforms, switch trials generated a larger parietal positive event-related potential (ERP), and a larger slow parietal positivity compared with repeat trials in the short and long CSI condition. Neural SC of cue-related ERP positivity was smaller in the long RSI condition. For stimulus-locked waveforms, a larger switch-related central negative ERP component was observed, and the neural SC of the ERP negativity was smaller in the long CSI. Results of standardized low resolution electromagnetic tomography (sLORETA) for both ERP positivity and negativity showed that switch trials evoked larger activation than repeat trials in dorsolateral prefrontal cortex (DLPFC) and posterior parietal cortex (PPC). Conclusions/Significance The results provide evidence that both RSI and CSI modulate the neural activities in the process of task-switching, but that these have a differential role during task-set reconfiguration and passive dissipation of a previously relevant task-set. PMID:22860090

Non-Identity-Mediated CRISPR-Bacteriophage Interaction Mediated via the Csy and Cas3 Proteins ▿#

PubMed Central

Cady, Kyle C.; O'Toole, George A.

2011-01-01

Studies of the Escherichia, Neisseria, Thermotoga, and Mycobacteria clustered regularly interspaced short palindromic repeat (CRISPR) subtypes have resulted in a model whereby CRISPRs function as a defense system against bacteriophage infection and conjugative plasmid transfer. In contrast, we previously showed that the Yersinia-subtype CRISPR region of Pseudomonas aeruginosa strain UCBPP-PA14 plays no detectable role in viral immunity but instead is required for bacteriophage DMS3-dependent inhibition of biofilm formation by P. aeruginosa. The goal of this study is to define the components of the Yersinia-subtype CRISPR region required to mediate this bacteriophage-host interaction. We show that the Yersinia-subtype-specific CRISPR-associated (Cas) proteins Csy4 and Csy2 are essential for small CRISPR RNA (crRNA) production in vivo, while the Csy1 and Csy3 proteins are not absolutely required for production of these small RNAs. Further, we present evidence that the core Cas protein Cas3 functions downstream of small crRNA production and that this protein requires functional HD (predicted phosphohydrolase) and DEXD/H (predicted helicase) domains to suppress biofilm formation in DMS3 lysogens. We also determined that only spacer 1, which is not identical to any region of the DMS3 genome, mediates the CRISPR-dependent loss of biofilm formation. Our evidence suggests that gene 42 of phage DMS3 (DMS3-42) is targeted by CRISPR2 spacer 1 and that this targeting tolerates multiple point mutations between the spacer and DMS3-42 target sequence. This work demonstrates how the interaction between P. aeruginosa strain UCBPP-PA14 and bacteriophage DMS3 can be used to further our understanding of the diverse roles of CRISPR system function in bacteria. PMID:21398535

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

Rao, G.S.J.; Cook, P.F.; Harris, B.G.

Treatment of the Ascaris suum phosphofructokinase (PFK) with 2{prime},3{prime}-dialdehyde ATP (oATP) results in an enzyme form that is inactive. The conformational integrity of the active site, however, is preserved, suggesting that oATP modification locks the PFK into an inactive T state that cannot be activated. A rapid, irreversible first-order inactivation of the PFK is observed in the presence of oATP. The rate of inactivation is saturable and gives a K{sub oATP} of 1.07 {plus minus} 0.27 mM. Complete protection against inactivation is afforded by high concentrations of ATP. This desensitized enzyme incorporates only 0.2-0.3 mol of ({sup 3}H)oATP/subunit, suggesting thatmore » in te native enzyme inactivation perhaps results from the modification of the ATP inhibitory site rather than the catalytic site. Modification of an active-site thiol by 4,4{prime}-dithiodipyridine is prevented yb ATP before and after oATP treatment. Finally, gel filtration HPLC studies show that the oATP-modified enzyme retains its tetrameric state and neither the tryptophan fluorescence nor the circular dichroic spectra of the modified enzyme are affected by fructose 2,6-bisphosphate, suggesting that the enzyme is locked into a tetrameric inactive T state.« less

Role of N-terminal domain and accessory subunits in controlling deactivation-inactivation coupling of Kv4.2 channels.

PubMed

Barghaan, Jan; Tozakidou, Magdalini; Ehmke, Heimo; Bähring, Robert

2008-02-15

We examined the relationship between deactivation and inactivation in Kv4.2 channels. In particular, we were interested in the role of a Kv4.2 N-terminal domain and accessory subunits in controlling macroscopic gating kinetics and asked if the effects of N-terminal deletion and accessory subunit coexpression conform to a kinetic coupling of deactivation and inactivation. We expressed Kv4.2 wild-type channels and N-terminal deletion mutants in the absence and presence of Kv channel interacting proteins (KChIPs) and dipeptidyl aminopeptidase-like proteins (DPPs) in human embryonic kidney 293 cells. Kv4.2-mediated A-type currents at positive and deactivation tail currents at negative membrane potentials were recorded under whole-cell voltage-clamp and analyzed by multi-exponential fitting. The observed changes in Kv4.2 macroscopic inactivation kinetics caused by N-terminal deletion, accessory subunit coexpression, or a combination of the two maneuvers were compared with respective changes in deactivation kinetics. Extensive correlation analyses indicated that modulatory effects on deactivation closely parallel respective effects on inactivation, including both onset and recovery kinetics. Searching for the structural determinants, which control deactivation and inactivation, we found that in a Kv4.2 Delta 2-10 N-terminal deletion mutant both the initial rapid phase of macroscopic inactivation and tail current deactivation were slowed. On the other hand, the intermediate and slow phase of A-type current decay, recovery from inactivation, and tail current decay kinetics were accelerated in Kv4.2 Delta 2-10 by KChIP2 and DPPX. Thus, a Kv4.2 N-terminal domain, which may control both inactivation and deactivation, is not necessary for active modulation of current kinetics by accessory subunits. Our results further suggest distinct mechanisms for Kv4.2 gating modulation by KChIPs and DPPs.

Active vibration absorber for CSI evolutionary model: Design and experimental results

NASA Technical Reports Server (NTRS)

Bruner, Anne M.; Belvin, W. Keith; Horta, Lucas G.; Juang, Jer-Nan

1991-01-01

The development of control of large flexible structures technology must include practical demonstration to aid in the understanding and characterization of controlled structures in space. To support this effort, a testbed facility was developed to study practical implementation of new control technologies under realistic conditions. The design is discussed of a second order, acceleration feedback controller which acts as an active vibration absorber. This controller provides guaranteed stability margins for collocated sensor/actuator pairs in the absence of sensor/actuator dynamics and computational time delay. The primary performance objective considered is damping augmentation of the first nine structural modes. Comparison of experimental and predicted closed loop damping is presented, including test and simulation time histories for open and closed loop cases. Although the simulation and test results are not in full agreement, robustness of this design under model uncertainty is demonstrated. The basic advantage of this second order controller design is that the stability of the controller is model independent.

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.

CSI Flight Computer System and experimental test results

NASA Technical Reports Server (NTRS)

Sparks, Dean W., Jr.; Peri, F., Jr.; Schuler, P.

1993-01-01

This paper describes the CSI Computer System (CCS) and the experimental tests performed to validate its functionality. This system is comprised of two major components: the space flight qualified Excitation and Damping Subsystem (EDS) which performs controls calculations; and the Remote Interface Unit (RIU) which is used for data acquisition, transmission, and filtering. The flight-like RIU is the interface between the EDS and the sensors and actuators positioned on the particular structure under control. The EDS and RIU communicate over the MIL-STD-1553B, a space flight qualified bus. To test the CCS under realistic conditions, it was connected to the Phase-0 CSI Evolutionary Model (CEM) at NASA Langley Research Center. The following schematic shows how the CCS is connected to the CEM. Various tests were performed which validated the ability of the system to perform control/structures experiments.

Multiplexed CRISPR/Cas9 Genome Editing and Gene Regulation Using Csy4 in Saccharomyces cerevisiae.

PubMed

Ferreira, Raphael; Skrekas, Christos; Nielsen, Jens; David, Florian

2018-01-19

Clustered regularly interspaced short palindromic repeats (CRISPR) technology has greatly accelerated the field of strain engineering. However, insufficient efforts have been made toward developing robust multiplexing tools in Saccharomyces cerevisiae. Here, we exploit the RNA processing capacity of the bacterial endoribonuclease Csy4 from Pseudomonas aeruginosa, to generate multiple gRNAs from a single transcript for genome editing and gene interference applications in S. cerevisiae. In regards to genome editing, we performed a quadruple deletion of FAA1, FAA4, POX1 and TES1 reaching 96% efficiency out of 24 colonies tested. Then, we used this system to efficiently transcriptionally regulate the three genes, OLE1, HMG1 and ACS1. Thus, we demonstrate that multiplexed genome editing and gene regulation can be performed in a fast and effective manner using Csy4.

Highly improved passivation of c-Si surfaces using a gradient i a-Si:H layer

NASA Astrophysics Data System (ADS)

Lee, Soonil; Ahn, Jaehyun; Mathew, Leo; Rao, Rajesh; Zhang, Zhongjian; Kim, Jae Hyun; Banerjee, Sanjay K.; Yu, Edward T.

2018-04-01

Surface passivation using intrinsic a-Si:H (i a-Si:H) films plays a key role in high efficiency c-Si heterojunction solar cells. In this study, we demonstrate improved passivation quality using i a-Si:H films with a gradient-layered structure consisting of interfacial, transition, and capping layers deposited on c-Si surfaces. The H2 dilution ratio (R) during deposition was optimized individually for the interfacial and capping layers, which were separated by a transition layer for which R changed gradually between its values for the interfacial and capping layers. This approach yielded a significant reduction in surface carrier recombination, resulting in improvement of the minority carrier lifetime from 1480 μs for mono-layered i a-Si:H passivation to 2550 μs for the gradient-layered passivation approach.

A copula-multifractal volatility hedging model for CSI 300 index futures

NASA Astrophysics Data System (ADS)

Wei, Yu; Wang, Yudong; Huang, Dengshi

2011-11-01

In this paper, we propose a new hedging model combining the newly introduced multifractal volatility (MFV) model and the dynamic copula functions. Using high-frequency intraday quotes of the spot Shanghai Stock Exchange Composite Index (SSEC), spot China Securities Index 300 (CSI 300), and CSI 300 index futures, we compare the direct and cross hedging effectiveness of the copula-MFV model with several popular copula-GARCH models. The main empirical results show that the proposed copula-MFV model obtains better hedging effectiveness than the copula-GARCH-type models in general. Furthermore, the hedge operating strategy based MFV hedging model involves fewer transaction costs than those based on the GARCH-type models. The finding of this paper indicates that multifractal analysis may offer a new way of quantitative hedging model design using financial futures.

An ab initio study on the effect of iron atom junction on transport characteristics of carbon-silicon mixed chain

NASA Astrophysics Data System (ADS)

Hu, Wei; Zhou, Qinghua; Liu, Wenhua; Liang, Yan; Wang, Tao; Wan, Haiqing

2018-04-01

The effect of iron atom junction on transport characteristics of carbon-silicon mixed chain has been studied from an ab initio study. At zero bias, the Fe(CSi)n system appears to be the decrease of the conductance as the number of the Si-C pairs in the chain increases (n changes). When n > 5, the conductance tends to zero. These changes are independent of the transferring charge of the system, depending on the coupling of the electrodes and the central region. Under bias, the higher the bias voltage, the bigger the transmission coefficient of the system, and the transmission peak moves closer to the Fermi level. The I-V curves of Fe(CSi)2 and Fe (CSi)3 are linear, showing the behavior of metal resistance.

Solar Photothermal Disinfection using Broadband-Light Absorbing Gold Nanoparticles and Carbon Black.

PubMed

Loeb, Stephanie; Li, Chuanhao; Kim, Jae-Hong

2018-01-02

A simple heat treatment, perhaps the most globally recognized point-of-use water sterilization method, is seemingly effective against all major pathogens of concern, but bulk water boiling is not energy efficient or sustainable. Herein, we present the first application of solar-to-thermal converting nanomaterials for the direct inactivation of bacteria and viruses in drinking water through the application of Au nanorods, carbon black, and Au nanorod-carbon black composite materials as light absorbers. With broad absorption bands spanning the visible and near-infrared wavelengths, at sufficient concentrations, these nanoparticles induce multiple scattering events, increasing photon absorption probability and concentrating the light within a small spatial domain, leading to localized, intense heating that inactivates microorganisms in close proximity. Moving toward practical device design, we have developed a facile silane immobilization approach to fabricate films with densely packed layers of photothermal nanomaterials. Our results suggest that upon irraditaion with simulated solar light, these films can thermally inactivate bacteria and viruses, as demonstrated through the inactivation of surrogate organisms Escherichia coli K-12, and bacteriophages MS2 and PR772.

Hydrazine vapor inactivates Bacillus spores

NASA Astrophysics Data System (ADS)

Schubert, Wayne W.; Engler, Diane L.; Beaudet, Robert A.

2016-05-01

NASA policy restricts the total number of bacterial spores that can remain on a spacecraft traveling to any planetary body which might harbor life or have evidence of past life. Hydrazine, N2H4, is commonly used as a propellant on spacecraft. Hydrazine as a liquid is known to inactivate bacterial spores. We have now verified that hydrazine vapor also inactivates bacterial spores. After Bacillus atrophaeus ATCC 9372 spores deposited on stainless steel coupons were exposed to saturated hydrazine vapor in closed containers, the spores were recovered from the coupons, serially diluted, pour plated and the surviving bacterial colonies were counted. The exposure times required to reduce the spore population by a factor of ten, known as the D-value, were 4.70 ± 0.50 h at 25 °C and 2.85 ± 0.13 h at 35 °C. These inactivation rates are short enough to ensure that the bioburden of the surfaces and volumes would be negligible after prolonged exposure to hydrazine vapor. Thus, all the propellant tubing and internal tank surfaces exposed to hydrazine vapor do not contribute to the total spore count.

Field and laboratory investigations of inactivation of viruses (PRD1 and MS2) attached to iron oxide-coated quartz san

USGS Publications Warehouse

Ryan, Joseph N.; Harvey, Ronald W.; Metge, David W.; Elimelech, Menachem; Navigato, Theresa; Pieper, Ann P.

2002-01-01

Field and laboratory experiments were conducted to investigate inactivation of viruses attached to mineral surfaces. In a natural gradient transport field experiment, bacteriophage PRD1, radiolabeled with 32P, was injected into a ferric oxyhydroxide-coated sand aquifer with bromide and linear alkylbenzene sulfonates. In a zone of the aquifer contaminated by secondary sewage infiltration, small fractions of infective and 32P-labeled PRD1 broke through with the bromide tracer, followed by the slow release of 84% of the 32P activity and only 0.011% of the infective PRD1. In the laboratory experiments, the inactivation of PRD1, labeled with 35S (protein capsid), and MS2, dual radiolabeled with 35S (protein capsid) and 32P (nucleic acid), was monitored in the presence of groundwater and sediment from the contaminated zone of the field site. Release of infective viruses decreased at a much faster rate than release of the radiolabels, indicating that attached viruses were undergoing surface inactivation. Disparities between 32P and35S release suggest that the inactivated viruses were released in a disintegrated state. Comparison of estimated solution and surface inactivation rates indicates solution inactivation is ∼3 times as fast as surface inactivation. The actual rate of surface inactivation may be substantially underestimated owing to slow release of inactivated viruses.

Modulation Characterization Techniques

DTIC Science & Technology

1991-04-01

34Advanced Communication Processing Techniques" was organized and held in Ruidoso , New Mexico, May 14-17, 1989. Dr. Charles Weber’s participation involved...to attend and deliver presentations at MILCOM 󈨜. • Dr. Charles Weber travelled to Ruidoso , NM, to chair the session on Modulation...Characterization at the CSI Workshop May 14-17, 1989. 26 r * Dr. Andreas Polydoros travelled to Ruidoso , NM, to attend the CSI Workshop "Advanced Communication

Validation of the Chinese version of the Modified Caregivers Strain Index among Hong Kong caregivers: an initiative of medical social workers.

PubMed

Chan, Wallace Chi Ho; Chan, Christopher L F; Suen, Margaret

2013-11-01

Family caregivers may often experience caregiving stress and burden. To systematically assess this issue, medical social workers may need to use a brief and valid measurement in their practice. In the Hong Kong Chinese context, one additional challenge is to examine whether a measurement developed in the West is valid for Hong Kong Chinese caregivers. Thus, medical social workers in Hong Kong initiated this research study to validate the Chinese version of the Modified Caregiver Strain Index (C-M-CSI). A total of 223 Chinese caregivers of patients with various chronic illnesses were recruited for this validation study. C-M-CSI demonstrated good reliability (Cronbach's alpha coefficient = .91), concurrent validity with the Chinese version of the Caregiver Burden Inventory, and discriminant validity with the Chinese version of the Meaning in Life Questionnaire. Factor analysis yielded a single factor as the original M-CSI, which explained 49 percent of variance. Construct validity was shown by differentiating spousal and nonspousal caregivers, as well as caregivers of patients with and without behavioral problems. C-M-CSI is recommended as a brief and valid measurement that can be used by medical social workers in assessing the caregiving strain of Chinese caregivers of patients in Hong Kong.

Sparring and neurological function in professional boxers.

PubMed

Stiller, John W; Yu, Steven S; Brenner, Lisa A; Langenberg, Patricia; Scrofani, Phillip; Pannella, Patrick; Hsu, Edbert B; Roberts, Darryl W; Monsell, Ray M T; Binks, Sidney W; Guzman, Alvaro; Postolache, Teodor T

2014-01-01

Despite increased interest regarding the potentially long-term negative impact of chronic traumatic brain injury, limited research has been conducted regarding such injuries and neurological outcomes in real world settings. To increase understanding regarding the relationship between sparring (e.g., training under the tutelage of an experienced boxing coach for the purpose of improving skills and/or fitness) and neurological functioning, professional boxers (n = 237) who competed in Maryland between 2003 and 2008 completed measures regarding sparring exposure (Cumulative Sparring Index, CSI) and performance on tests of cognition (Symbol Digit Modalities Test, SDMT) and balance (Sharpened Romberg Test, SRT). Measures were completed prior to boxing matches. Higher scores on the CSI (increased sparring exposure) were associated with poorer performance on both tests of cognition (SDMT) and balance (SRT). A threshold effect was noted regarding performance on the SDMT, with those reporting CSI values greater than about 150 experiencing a decline in cognition. A history of frequent and/or intense sparring may pose a significant risk for developing boxing associated neurological sequelae. Implementing administration of clinically meaningful tests before bouts, such as the CSI, SDMT, and/or the SRT, as well as documentation of results into the boxer's physicals or medical profiles may be an important step for improving boxing safety.

Sparring and Neurological Function in Professional Boxers

PubMed Central

Stiller, John W.; Yu, Steven S.; Brenner, Lisa A.; Langenberg, Patricia; Scrofani, Phillip; Pannella, Patrick; Hsu, Edbert B.; Roberts, Darryl W.; Monsell, Ray M. T.; Binks, Sidney W.; Guzman, Alvaro; Postolache, Teodor T.

2014-01-01

Despite increased interest regarding the potentially long-term negative impact of chronic traumatic brain injury, limited research has been conducted regarding such injuries and neurological outcomes in real world settings. To increase understanding regarding the relationship between sparring (e.g., training under the tutelage of an experienced boxing coach for the purpose of improving skills and/or fitness) and neurological functioning, professional boxers (n = 237) who competed in Maryland between 2003 and 2008 completed measures regarding sparring exposure (Cumulative Sparring Index, CSI) and performance on tests of cognition (Symbol Digit Modalities Test, SDMT) and balance (Sharpened Romberg Test, SRT). Measures were completed prior to boxing matches. Higher scores on the CSI (increased sparring exposure) were associated with poorer performance on both tests of cognition (SDMT) and balance (SRT). A threshold effect was noted regarding performance on the SDMT, with those reporting CSI values greater than about 150 experiencing a decline in cognition. A history of frequent and/or intense sparring may pose a significant risk for developing boxing associated neurological sequelae. Implementing administration of clinically meaningful tests before bouts, such as the CSI, SDMT, and/or the SRT, as well as documentation of results into the boxer’s physicals or medical profiles may be an important step for improving boxing safety. PMID:25101253

Traditional and online consumers in China: a preliminary study of their personality traits and decision-making styles.

PubMed

Zhu, Junpeng; Xu, You; Huang, Jingyi; Yeow, Changdar; Wang, Wei

2012-12-01

Population of online consumers increases rapidly, but the decision-making styles of online consumers and psychiatric denominators such as the personality correlates remain unclear. In 196 traditional, and 196 age-, education- and gender-matched online consumers, we have tested the Zuckerman-Kuhlman Personality Questionnaire (ZKPQ) and the Consumer Style Inventory (CSI). After exploratory and confirmatory factor analyses, we have defined a five-factor model CSI with 24 items. Online consumers scored lower on ZKPQ Neuroticism-Anxiety and higher on Aggression-Hostility than traditional ones did, and scored higher on CSI Novelty-fashion consciousness and Brand consciousness, and lower on Time consciousness than the traditional consumers did. ZKPQ Neuroticism-Anxiety was positively correlated with CSI Confused by overchoice in both groups, Sociability was positively correlated with Novelty-fashion consciousness and negatively with Time consciousness in traditional group, and Impulsive Sensation Seeking was positively correlated with Novelty-fashion consciousness and Time consciousness in online group. Our study suggests that, regarding the decision-making styles, online consumers display curiosity that lacks security and need other ways to improve their social lives. It also calls further designs to address the contributions of other psychiatric features to the particular decision-making styles in online consumers.

Measurement Properties of the Central Sensitization Inventory: A Systematic Review.

PubMed

Scerbo, Thomas; Colasurdo, Joseph; Dunn, Sally; Unger, Jacob; Nijs, Jo; Cook, Chad

2018-04-01

Central sensitization (CS) is a phenomenon associated with several medical diagnoses, including postcancer pain, low back pain, osteoarthritis, whiplash, and fibromyalgia. CS involves an amplification of neural signaling within the central nervous system that results in pain hypersensitivity. The purpose of this systematic review was to gather published studies of a widely used outcome measure (the Central Sensitization Inventory [CSI]), determine the quality of evidence these publications reported, and examine the measurement properties of the CSI. Four databases were searched for publications from 2011 (when the CSI was developed) to July 2017. The Consensus-Based Standards for the Selection of Health Measurement Instruments (COSMIN) checklist was applied to evaluate methodological quality and risk of bias. In instances when COSMIN did not offer a scoring system for measurement properties, qualitative analyses were performed. Fourteen studies met inclusion criteria. Quality of evidence examined with the COSMIN checklist was determined to be good to excellent for all studies for their respective measurement property reports. Interpretability measures were consistent when publications were analyzed qualitatively, and construct validity was strong when examined alongside other validated measures relating to CS. An assessment of the published measurement studies of the CSI suggest the tool generates reliable and valid data that quantify the severity of several symptoms of CS. © 2017 World Institute of Pain.

A five-layer users' need hierarchy of computer input device selection: a contextual observation survey of computer users with cervical spinal injuries (CSI).

PubMed

Tsai, Tsai-Hsuan; Nash, Robert J; Tseng, Kevin C

2009-05-01

This article presents how the researcher goes about answering the research question, 'how assistive technology impacts computer use among individuals with cervical spinal cord injury?' through an in-depth investigation into the real-life situations among computer operators with cervical spinal cord injuries (CSI). An in-depth survey was carried out to provide an insight into the function abilities and limitation, habitual practice and preference, choices and utilisation of input devices, personal and/or technical assistance, environmental set-up and arrangements and special requirements among 20 experienced computer users with cervical spinal cord injuries. Following the survey findings, a five-layer CSI users' needs hierarchy of input device selection and use was proposed. These needs were ranked in order: beginning with the most basic criterion at the bottom of the pyramid; lower-level criteria must be met before one moves onto the higher level. The users' needs hierarchy for CSI computer users, which had not been applied by previous research work and which has established a rationale for the development of alternative input devices. If an input device achieves the criteria set up in the needs hierarchy, then a good match of person and technology will be achieved.

Determination of combined sibship indices "gray zone" using 15 STR loci for central Bosnian human population.

PubMed

Musanovic, Jasmin; Filipovska-Musanovic, Marijana; Kovacevic, Lejla; Buljugic, Dzenisa; Dzehverovic, Mirela; Avdic, Jasna; Marjanovic, Damir

2012-05-01

In our previous population studies of Bosnia and Herzegovina human population, we have used autosomal STR, Y-STR, and X-STR loci, as well as Y-chromosome NRY biallelic markers. All obtained results were included in Bosnian referent database. In order of future development of applied population molecular genetics researches of Bosnia and Herzegovina human population, we have examined the effectiveness of 15 STR loci system in determination of sibship by using 15 STR loci and calculating different cut-off points of combined sibship indices (CSI) and distribution of sharing alleles. From the perspective of its application, it is very difficult and complicated to establish strict CSI cut-off values for determination of the doubtless sibship. High statistically significant difference between the means of CSI values and in distribution of alleles sharing in siblings and non-siblings was noticed (P < 0.0001). After constructing the "gray zone", only one false positive result was found in three CSI cut-off levels with the highest percent of determined sibship/non-sibship at the CSI = 0.067, confirming its practical benefit. Concerning the distribution of sharing alleles, it is recommended as an informative estimator for its usage within Bosnia and Herzegovina human population.

Wavelength-Specific UV Inactivation, Molecular Mechanisms, and Potential Synergies

EPA Science Inventory

This work evaluated UV LEDs emitting at 260 nm, 280 nm, and the combination of 260|280 nm together for their efficacy in inactivating a common fecal indicator, E. coli, as well as human enteric viruses on the United States Environmental Protection Agency’s contaminant candi...

Binding of benzocaine in batrachotoxin-modified Na+ channels. State- dependent interactions

PubMed Central

1994-01-01

Hille (1977. Journal of General Physiology. 69:497-515) first proposed a modulated receptor hypothesis (MRH) to explain the action of benzocaine in voltage-gated Na+ channels. Using the MRH as a framework, we examined benzocaine binding in batrachotoxin (BTX)-modified Na+ channels under voltage-clamp conditions using either step or ramp command signals. We found that benzocaine binding is strongly voltage dependent. At -70 mV, the concentration of benzocaine that inhibits 50% of BTX-modified Na+ currents in GH3 cells (IC50) is 0.2 mM, whereas at +50 mV, the IC50 is 1.3 mM. Dose-response curves indicate that only one molecule of benzocaine is required to bind with one BTX-modified Na+ channel at -70 mV, whereas approximately two molecules are needed at +50 mV. Upon treatment with the inactivation modifier chloramine-T, the binding affinity of benzocaine is reduced significantly at -70 mV, probably as a result of the removal of the inactivated state of BTX- modified Na+ channels. The same treatment, however, enhances the binding affinity of cocaine near this voltage. External Na+ ions appear to have little effect on benzocaine binding, although they do affect cocaine binding. We conclude that two mechanisms underlie the action of local anesthetics in BTX-modified Na+ channels. Unlike open-channel blockers such as cocaine and bupivacaine, neutral benzocaine binds preferentially with BTX-modified Na+ channels in a closed state. Furthermore, benzocaine can be modified chemically so that it behaves like an open-channel blocker. This compound also elicits a use- dependent block in unmodified Na+ channels after repetitive depolarizations, whereas benzocaine does not. The implications of these findings for the MRH theory will be discussed. PMID:8195785

The saponin monomer of dwarf lilyturf tuber, DT-13, reduces L-type calcium currents during hypoxia in adult rat ventricular myocytes.

PubMed

Tao, Jin; Wang, Hongyi; Zhou, Hong; Li, Shengnan

2005-10-28

The saponin monomer 13 of dwarf lilyturf tuber (DT-13), one of the saponin monomers of dwarf lilyturf tuber, has been found to have potent cardioprotective effects. In order to investigate the effects of DT-13 on L-type calcium currents (I(Ca,L)), exploring the mechanisms of DT-13's cardioprotective effects in the condition of pathophysiology, we directly measured the I(Ca,L) during hypoxia in the adult rat cardiac myocytes exposed to DT-13 using standard whole-cell patch-clamp recording technique. Our previous results showed that DT-13 exerted decreasing effects on the I(Ca,L) of the single adult rat cardiac myocytes. In the condition of hypoxia, the current density was inhibited by about 29% after exposure of the cells to DT-13 (0.1 micromol L(-1)) for 10 min, from 6.96+/-1.05 pA/pF to 4.38+/-0.35 pA/pF (n=5, P<0.05). This I(Ca,L)-inhibiting action of DT-13 was concentration-dependent and showed no frequency-dependence. DT-13 up-shifted the current-voltage (I-V) curve. Steady-state activation of I(Ca,L) was not affected markedly, and the half activation potential (V(0.5)) in the presence of DT-13 (0.1 micromol L(-1)) was also not significantly different. DT-13 at 0.1 micromol L(-1) markedly accelerated the voltage-dependent steady-state inactivation of calcium current and shifted the steady-state inactivation curve of I(Ca,L) to the left. In combination with previous reports, these results suggest that there might be a close relationship between the cardioprotective effects of DT-13 and L-type calcium channels in the condition of hypoxia.

Bimodal Action of Protons on ATP Currents of Rat PC12 Cells

PubMed Central

Skorinkin, Andrei; Nistri, Andrea; Giniatullin, Rashid

2003-01-01

The mode of action of extracellular protons on ATP-gated P2X2 receptors remains controversial as either enhancement or depression of ATP-mediated currents has been reported. By investigating, at different pH, the electrophysiological effect of ATP on P2X2 receptors and complementing it with receptor modelling, the present study suggests a unified mechanism for both potentiation and inactivation of ATP receptors by protons. Our experiments on patch-clamped PC12 cells showed that, on the same cell, mild acidification potentiated currents induced by low ATP concentrations (<0.1 mM) and attenuated responses to high ATP concentrations (>1 mM) with emergence of current fading and rebound. To clarify the nature of the ATP/H+ interaction, we used the Ding and Sachs's “loop” receptor model which best describes the behavior of such receptors with two open states linked via one inactivated state. No effects by protons could be ascribed to H+-mediated open channel block. However, by assuming that protons facilitated binding of ATP to resting as well as open receptors, the model could closely replicate H+-induced potentiation of currents evoked by low ATP doses plus fading and rebound induced by high ATP doses. The latter phenomenon was due to receptor transition to the inactive state. The present data suggest that the high concentration of protons released with ATP (and catecholamines) from secretory vesicles may allow a dual action of H+ on P2X2 receptors. This condition might also occur on P2X2 receptors of central neurons exposed to low pH during ischemia. PMID:12810852

Secure Multiuser Communications in Wireless Sensor Networks with TAS and Cooperative Jamming

PubMed Central

Yang, Maoqiang; Zhang, Bangning; Huang, Yuzhen; Yang, Nan; Guo, Daoxing; Gao, Bin

2016-01-01

In this paper, we investigate the secure transmission in wireless sensor networks (WSNs) consisting of one multiple-antenna base station (BS), multiple single-antenna legitimate users, one single-antenna eavesdropper and one multiple-antenna cooperative jammer. In an effort to reduce the scheduling complexity and extend the battery lifetime of the sensor nodes, the switch-and-stay combining (SSC) scheduling scheme is exploited over the sensor nodes. Meanwhile, transmit antenna selection (TAS) is employed at the BS and cooperative jamming (CJ) is adopted at the jammer node, aiming at achieving a satisfactory secrecy performance. Moreover, depending on whether the jammer node has the global channel state information (CSI) of both the legitimate channel and the eavesdropper’s channel, it explores a zero-forcing beamforming (ZFB) scheme or a null-space artificial noise (NAN) scheme to confound the eavesdropper while avoiding the interference to the legitimate user. Building on this, we propose two novel hybrid secure transmission schemes, termed TAS-SSC-ZFB and TAS-SSC-NAN, for WSNs. We then derive the exact closed-form expressions for the secrecy outage probability and the effective secrecy throughput of both schemes to characterize the secrecy performance. Using these closed-form expressions, we further determine the optimal switching threshold and obtain the optimal power allocation factor between the BS and jammer node for both schemes to minimize the secrecy outage probability, while the optimal secrecy rate is decided to maximize the effective secrecy throughput for both schemes. Numerical results are provided to verify the theoretical analysis and illustrate the impact of key system parameters on the secrecy performance. PMID:27845753

Inactivation of feline calicivirus, a norovirus surrogate, by chlorine dioxide gas.

PubMed

Morino, Hirofumi; Fukuda, Toshiaki; Miura, Takanori; Lee, Cheolsung; Shibata, Takashi; Sanekata, Takeshi

2009-12-01

The efficacy of gaseous chlorine dioxide (ClO2) against feline calicivirus (FCV), a norovirus surrogate, in the dry and the wet states on a hard surface was evaluated. We demonstrated that low-concentration ClO2 gas (mean 0.08 ppm, 0.22 microg/I) could inactivate FCV in the wet state with 0.5% fetal bovine serum (FBS) within 6 h in 45 to 55% relative humidity (RH) (> 3 log10 reductions) and FCV in the dry state with 2% FBS (percentage of FBS in the viral suspension) within 10 h in 75 to 85% RH (> 3 log10 reductions) at 20 degrees C, respectively. Furthermore, a < 0.3 ppm concentration of ClO2 gas (mean 0.26 ppm, 0.73 microg/l) could inactivate (below the detection limit) FCV in the dry state with 5% FBS within 24 h in 75 to 85% RH at 20 degrees C. In contrast, in 45 to 55% RH at 20 degrees C, ClO2 gas had little effect even when the FCV in the dry state was exposed to high-concentration ClO2 (mean 8 ppm, 22.4 microg/l) for 24 h. These results suggest that humidity plays an important role in the inactivation by ClO2 gas of FCV in the dry state. According to the International Chemical Safety Card, threshold limit values for ClO2 gas are 0.1 ppm as an 8-h time-weighted average and 0.3 ppm as a 15 min short-term exposure limit. From these data, we propose that the treatment of wet areas of human activity such as kitchens, toilets, etc., with low-concentration ClO2 gas would be useful for reducing the risk of infection by noroviruses (NV) without adverse effects. In addition, we believe that the application of a combination of a < 0.3 ppm concentration of ClO2 gas and a humidifier in places without human activity may make it possible to inactivate NV in the dry state on any surface within a contaminated room without serious adverse effects.

Integrated modeling and analysis of a space-truss article

NASA Technical Reports Server (NTRS)

Stockwell, Alan E.; Perez, Sharon E.; Pappa, Richard S.

1990-01-01

MSC/NASTRAN is being used in the Controls-Structures Interaction (CSI) program at NASA Langley Research Center as a key analytical tool for structural analysis as well as the basis for control law development, closed-loop performance evaluation, and system safety checks. Guest investigators from academia and industry are performing dynamics and control experiments on a flight-like deployable space truss called Mini-Mast to determine the effectiveness of various active-vibration control laws. MSC/NASTRAN was used to calculate natural frequencies and mode shapes below 100 Hz to describe the dynamics of the 20-meter-long lightweight Mini-Mast structure. Gravitational effects contribute significantly to structural stiffness and are accounted for through a two-phase solution in which the differential stiffness matrix is calculated and then used in the eigensolution. Reduced modal models are extracted for control law design and evaluation of closed-loop system performance. Predicted actuator forces from controls simulations are then applied to the extended model to predict member loads and stresses. These pre-test analyses reduce risks associated with the structural integrity of the test article, which is a major concern in closed-loop control experiments due to potential instabilities.

Cellular Injuries in Cronobacter sakazakii CIP 103183T and Salmonella enterica Exposed to Drying and Subsequent Heat Treatment in Milk Powder.

PubMed

Lang, Emilie; Guyot, Stéphane; Peltier, Caroline; Alvarez-Martin, Pablo; Perrier-Cornet, Jean-Marie; Gervais, Patrick

2018-01-01

Because of the ability of foodborne pathogens to survive in low-moisture foods, their decontamination is an important issue in food protection. This study aimed to clarify some of the cellular mechanisms involved in inactivation of foodborne pathogens after drying and subsequent heating. Individual strains of Salmonella Typhimurium, Salmonella Senftenberg, and Cronobacter sakazakii were mixed into whole milk powder and dried to different water activity levels (0.25 and 0.58); the number of surviving cells was determined after drying and subsequent thermal treatments in closed vessels at 90 and 100°C, for 30 and 120 s. For each condition, the percentage of unculturable cells was estimated and, in parallel, membrane permeability and respiratory activity were estimated by flow cytometry using fluorescent probes. After drying, it was clearly observable that the percentage of unculturable cells was correlated with the percentage of permeabilized cells (responsible for 20-40% of the total inactivated bacteria after drying), and to a lesser degree with the percentage of cells presenting with loss of respiratory activity. In contrast, the percentages of unculturable cells observed after heat treatment were strongly correlated with the loss of respiratory activity and weakly with membrane permeability (for 70-80% of the total inactivated bacteria after heat treatment). We conclude that cell inactivation during drying is closely linked to membrane permeabilization and that heat treatment of dried cells affects principally their respiratory activity. These results legitimize the use of time-temperature scales and allow better understanding of the cellular mechanisms of bacterial death during drying and subsequent heat treatment. These results may also allow better optimization of the decontamination process to ensure food safety by targeting the most deleterious conditions for bacterial cells without denaturing the food product.

Reactive hydroxyl radical-driven oral bacterial inactivation by radio frequency atmospheric plasma

NASA Astrophysics Data System (ADS)

Kang, Sung Kil; Choi, Myeong Yeol; Koo, Il Gyo; Kim, Paul Y.; Kim, Yoonsun; Kim, Gon Jun; Mohamed, Abdel-Aleam H.; Collins, George J.; Lee, Jae Koo

2011-04-01

We demonstrated bacterial (Streptococcus mutans) inactivation by a radio frequency power driven atmospheric pressure plasma torch with H2O2 entrained in the feedstock gas. Optical emission spectroscopy identified substantial excited state •OH generation inside the plasma and relative •OH formation was verified by optical absorption. The bacterial inactivation rate increased with increasing •OH generation and reached a maximum 5-log10 reduction with 0.6% H2O2 vapor. Generation of large amounts of toxic ozone is drawback of plasma bacterial inactivation, thus it is significant that the ozone concentration falls within recommended safe allowable levels with addition of H2O2 vapor to the plasma.

Accurate Sybil Attack Detection Based on Fine-Grained Physical Channel Information.

PubMed

Wang, Chundong; Zhu, Likun; Gong, Liangyi; Zhao, Zhentang; Yang, Lei; Liu, Zheli; Cheng, Xiaochun

2018-03-15

With the development of the Internet-of-Things (IoT), wireless network security has more and more attention paid to it. The Sybil attack is one of the famous wireless attacks that can forge wireless devices to steal information from clients. These forged devices may constantly attack target access points to crush the wireless network. In this paper, we propose a novel Sybil attack detection based on Channel State Information (CSI). This detection algorithm can tell whether the static devices are Sybil attackers by combining a self-adaptive multiple signal classification algorithm with the Received Signal Strength Indicator (RSSI). Moreover, we develop a novel tracing scheme to cluster the channel characteristics of mobile devices and detect dynamic attackers that change their channel characteristics in an error area. Finally, we experiment on mobile and commercial WiFi devices. Our algorithm can effectively distinguish the Sybil devices. The experimental results show that our Sybil attack detection system achieves high accuracy for both static and dynamic scenarios. Therefore, combining the phase and similarity of channel features, the multi-dimensional analysis of CSI can effectively detect Sybil nodes and improve the security of wireless networks.

Accurate Sybil Attack Detection Based on Fine-Grained Physical Channel Information

PubMed Central

Wang, Chundong; Zhao, Zhentang; Yang, Lei; Liu, Zheli; Cheng, Xiaochun

2018-01-01

With the development of the Internet-of-Things (IoT), wireless network security has more and more attention paid to it. The Sybil attack is one of the famous wireless attacks that can forge wireless devices to steal information from clients. These forged devices may constantly attack target access points to crush the wireless network. In this paper, we propose a novel Sybil attack detection based on Channel State Information (CSI). This detection algorithm can tell whether the static devices are Sybil attackers by combining a self-adaptive multiple signal classification algorithm with the Received Signal Strength Indicator (RSSI). Moreover, we develop a novel tracing scheme to cluster the channel characteristics of mobile devices and detect dynamic attackers that change their channel characteristics in an error area. Finally, we experiment on mobile and commercial WiFi devices. Our algorithm can effectively distinguish the Sybil devices. The experimental results show that our Sybil attack detection system achieves high accuracy for both static and dynamic scenarios. Therefore, combining the phase and similarity of channel features, the multi-dimensional analysis of CSI can effectively detect Sybil nodes and improve the security of wireless networks. PMID:29543773

The efficacy of education programme for preventing constipation in women.

PubMed

Ayaz, Sultan; Hisar, Filiz

2014-06-01

This study was performed to evaluate the efficiency of the education programme for prevention of constipation in women. This study was performed as a pre-test-posttest design. Thirty-five women were included who have constipation problem. Data were collected by questionnaire: Constipation Severity Instrument (CSI), Constipation Visual Analogue Scale (CVAS) and Bristol Stool Chart (BSC). Eight home visits were made for each of the women and they were followed up for 3 months. Participants received an individual education programme that included advice on dietary consumption such as pulpy-fibrous nutrient consumption, fluid intake, an exercise regime and counselling about optimal position to defecate. The subscales of 'Colonic Inertia' and 'Pain', and CSI total mean scores and CVAS mean scores were decreased significantly after education programme (P < 0.05). According to the BSC, 71.5% of the women stated their stool form to be 'sausage-shaped, but lumpy' before the education programme, but after the said programme the percentage had dropped to 17.1%. Education programme given to women who had constipation were determined to have been effective in alleviating constipation. Nurses should develop appropriate and effective strategies to help women prevent constipation. © 2013 Wiley Publishing Asia Pty Ltd.

Robust Weighted Sum Harvested Energy Maximization for SWIPT Cognitive Radio Networks Based on Particle Swarm Optimization.

PubMed

Tuan, Pham Viet; Koo, Insoo

2017-10-06

In this paper, we consider multiuser simultaneous wireless information and power transfer (SWIPT) for cognitive radio systems where a secondary transmitter (ST) with an antenna array provides information and energy to multiple single-antenna secondary receivers (SRs) equipped with a power splitting (PS) receiving scheme when multiple primary users (PUs) exist. The main objective of the paper is to maximize weighted sum harvested energy for SRs while satisfying their minimum required signal-to-interference-plus-noise ratio (SINR), the limited transmission power at the ST, and the interference threshold of each PU. For the perfect channel state information (CSI), the optimal beamforming vectors and PS ratios are achieved by the proposed PSO-SDR in which semidefinite relaxation (SDR) and particle swarm optimization (PSO) methods are jointly combined. We prove that SDR always has a rank-1 solution, and is indeed tight. For the imperfect CSI with bounded channel vector errors, the upper bound of weighted sum harvested energy (WSHE) is also obtained through the S-Procedure. Finally, simulation results demonstrate that the proposed PSO-SDR has fast convergence and better performance as compared to the other baseline schemes.

Adaptive limited feedback for interference alignment in MIMO interference channels.

PubMed

Zhang, Yang; Zhao, Chenglin; Meng, Juan; Li, Shibao; Li, Li

2016-01-01

It is very important that the radar sensor network has autonomous capabilities such as self-managing, etc. Quite often, MIMO interference channels are applied to radar sensor networks, and for self-managing purpose, interference management in MIMO interference channels is critical. Interference alignment (IA) has the potential to dramatically improve system throughput by effectively mitigating interference in multi-user networks at high signal-to-noise (SNR). However, the implementation of IA predominantly relays on perfect and global channel state information (CSI) at all transceivers. A large amount of CSI has to be fed back to all transmitters, resulting in a proliferation of feedback bits. Thus, IA with limited feedback has been introduced to reduce the sum feedback overhead. In this paper, by exploiting the advantage of heterogeneous path loss, we first investigate the throughput of IA with limited feedback in interference channels while each user transmits multi-streams simultaneously, then we get the upper bound of sum rate in terms of the transmit power and feedback bits. Moreover, we propose a dynamic feedback scheme via bit allocation to reduce the throughput loss due to limited feedback. Simulation results demonstrate that the dynamic feedback scheme achieves better performance in terms of sum rate.

Diversity Performance Analysis on Multiple HAP Networks.

PubMed

Dong, Feihong; Li, Min; Gong, Xiangwu; Li, Hongjun; Gao, Fengyue

2015-06-30

One of the main design challenges in wireless sensor networks (WSNs) is achieving a high-data-rate transmission for individual sensor devices. The high altitude platform (HAP) is an important communication relay platform for WSNs and next-generation wireless networks. Multiple-input multiple-output (MIMO) techniques provide the diversity and multiplexing gain, which can improve the network performance effectively. In this paper, a virtual MIMO (V-MIMO) model is proposed by networking multiple HAPs with the concept of multiple assets in view (MAV). In a shadowed Rician fading channel, the diversity performance is investigated. The probability density function (PDF) and cumulative distribution function (CDF) of the received signal-to-noise ratio (SNR) are derived. In addition, the average symbol error rate (ASER) with BPSK and QPSK is given for the V-MIMO model. The system capacity is studied for both perfect channel state information (CSI) and unknown CSI individually. The ergodic capacity with various SNR and Rician factors for different network configurations is also analyzed. The simulation results validate the effectiveness of the performance analysis. It is shown that the performance of the HAPs network in WSNs can be significantly improved by utilizing the MAV to achieve overlapping coverage, with the help of the V-MIMO techniques.

Tsallis entropy and decoherence of CsI quantum pseudo dot qubit

NASA Astrophysics Data System (ADS)

Tiotsop, M.; Fotue, A. J.; Fotsin, H. B.; Fai, L. C.

2017-05-01

Polaron in CsI quantum pseudo dot under an electromagnetic field was considered, and the ground and first excited state energies were derived by employing the combining Pekar variational and unitary transformation methods. With the two-level system obtained, single qubit was envisioned and the decoherence was studied using non-extensive entropy (Tsallis entropy). Numerical results showed: (i) the increase (decrease) of the energy levels (period of oscillation) with the increase of chemical potential, the zero point of pseudo dot, cyclotron frequency, and transverse and longitudinal confinements; (ii) the Tsallis entropy evolved as a wave envelop that increase with the increase of non-extenxive parameter and with the increase of electric field strength, zero point of pseudo dot and cyclotron frequency the wave envelop evolve periodically with reduction of period; (iii) The transition probability increases from the boundary to the centre of the dot where it has its maximum value. It was also noted that the probability density oscillate with period T0 = ℏ / Δ Ε with the tunnelling of the chemical potential and zero point of the pseudo dot. These results are helpful in the control of decoherence in quantum systems and may also be useful for the design of quantum computers.

40 CFR 141.400 - General requirements and applicability.

Code of Federal Regulations, 2010 CFR

2010-07-01

... requirements and applicability. (a) Scope of this subpart. The requirements of this subpart S constitute... systems that do not treat all of their ground water to at least 99.99 percent (4-log) treatment of viruses (using inactivation, removal, or a State-approved combination of 4-log virus inactivation and removal...

Compliance Determination for Inactivation Requirements of the National Primary Drinking Water Regulations when a Public Water Systems Uses Dichlor and Trichlor for Primary Disinfection

EPA Pesticide Factsheets

This memorandum has been developed to assist SDWA primacy agencies (EPA Regions, states and territories) when considering inactivation/disinfection compliance requirements for those water systems that choose to use Dichlor or Trichlor.

Wavelength-Specific UV Inactivation, Molecular Mechanisms, and Potential Synergies

EPA Science Inventory

This work evaluated UV LEDs emitting at 260 nm, 280 nm, and the combination of 260|280 nm together for their efficacy in inactivating a common fecal indicator, E. coli, as well as human enteric viruses on the United States Environmental Protection Agency’s contaminant candidate l...

Chlorine decay and bacterial inactivation kinetics in drinking water in the tropics.

PubMed

Thøgersen, J; Dahi, E

1996-09-01

The decay of free chlorine (Cl2) and combined chlorine (mostly monochloramine: NH2Cl) and the inactivation of bacteria was examined in Dar es Salaam, Tanzania. Batch experiments, pilot-scale pipe experiments and full-scale pipe experiments were carried out to establish the kinetics for both decay and inactivation, and to compare the two disinfectants for use under tropical conditions. The decay of both disinfectants closely followed first order kinetics, with respect to the concentration of both disinfectant and disinfectant-consuming substances. Bacterial densities exhibited a kinetic pattern consisting of first order inactivation with respect to the density of the bacteria and the concentration of the disinfectant, and first order growth with respect to the bacterial density. The disinfection kinetic model takes the decaying concentration of the disinfectant into account. The decay rate constant for free chlorine was 114 lg(-1)h(-1), while the decay rate constant for combined chlorine was 1.84 lg(-1)h(-1) (1.6% of the decay rate for free chlorine). The average concentration of disinfectant consuming substances in the water phase was 2.6 mg Cl2/l for free chlorine and 5.6 mg NH2Cl/l for combined chlorine. The decay rate constant and the concentration of disinfectant consuming substances when water was pumped through pipes, depended on whether or not chlorination was continuous. Combined chlorine especially could clean the pipes of disinfectant consuming substances. The inactivation rate constant λ, was estimated at 3.06×10(4) lg(-1)h(-1). Based on the inactivation rate constant, and a growth rate constant determined in a previous study, the critical concentration of free chlorine was found to be 0.08 mg Cl2/l. The critical concentration is a value below which growth rates dominate over inactivation.

Elimination of fast inactivation in Kv4 A-type potassium channels by an auxiliary subunit domain.

PubMed

Holmqvist, Mats H; Cao, Jie; Hernandez-Pineda, Ricardo; Jacobson, Michael D; Carroll, Karen I; Sung, M Amy; Betty, Maria; Ge, Pei; Gilbride, Kevin J; Brown, Melissa E; Jurman, Mark E; Lawson, Deborah; Silos-Santiago, Inmaculada; Xie, Yu; Covarrubias, Manuel; Rhodes, Kenneth J; Distefano, Peter S; An, W Frank

2002-01-22

The Kv4 A-type potassium currents contribute to controlling the frequency of slow repetitive firing and back-propagation of action potentials in neurons and shape the action potential in heart. Kv4 currents exhibit rapid activation and inactivation and are specifically modulated by K-channel interacting proteins (KChIPs). Here we report the discovery and functional characterization of a modular K-channel inactivation suppressor (KIS) domain located in the first 34 aa of an additional KChIP (KChIP4a). Coexpression of KChIP4a with Kv4 alpha-subunits abolishes fast inactivation of the Kv4 currents in various cell types, including cerebellar granule neurons. Kinetic analysis shows that the KIS domain delays Kv4.3 opening, but once the channel is open, it disrupts rapid inactivation and slows Kv4.3 closing. Accordingly, KChIP4a increases the open probability of single Kv4.3 channels. The net effects of KChIP4a and KChIP1-3 on Kv4 gating are quite different. When both KChIP4a and KChIP1 are present, the Kv4.3 current shows mixed inactivation profiles dependent on KChIP4a/KChIP1 ratios. The KIS domain effectively converts the A-type Kv4 current to a slowly inactivating delayed rectifier-type potassium current. This conversion is opposite to that mediated by the Kv1-specific "ball" domain of the Kv beta 1 subunit. Together, these results demonstrate that specific auxiliary subunits with distinct functions actively modulate gating of potassium channels that govern membrane excitability.

Nano-siRNA Particles and Combination Therapies for Ovarian Tumor Targeting

DTIC Science & Technology

2015-08-01

stable complexes than siRNA for systemic delivery. Our preliminary tests suggest that low molecular weight , biodegradable polymers give higher...transfection efficiencies for csiRNA or T1-csiRNA than polymers that have higher molecular weight or are not degradable. We will therefore design and screen...combinations of chemotherapy drugs with siRNA and molecular inhibitors shown to be effective in ovarian cancer, thus providing the opportunity for highly

Tomlinson-Harashima Precoding for Multiuser MIMO Systems With Quantized CSI Feedback and User Scheduling

NASA Astrophysics Data System (ADS)

Sun, Liang; McKay, Matthew R.

2014-08-01

This paper studies the sum rate performance of a low complexity quantized CSI-based Tomlinson-Harashima (TH) precoding scheme for downlink multiuser MIMO tansmission, employing greedy user selection. The asymptotic distribution of the output signal to interference plus noise ratio of each selected user and the asymptotic sum rate as the number of users K grows large are derived by using extreme value theory. For fixed finite signal to noise ratios and a finite number of transmit antennas $n_T$, we prove that as K grows large, the proposed approach can achieve the optimal sum rate scaling of the MIMO broadcast channel. We also prove that, if we ignore the precoding loss, the average sum rate of this approach converges to the average sum capacity of the MIMO broadcast channel. Our results provide insights into the effect of multiuser interference caused by quantized CSI on the multiuser diversity gain.

Properties of CsI, CsBr and GaAs thin films grown by pulsed laser deposition

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

Brendel, V M; Garnov, S V; Yagafarov, T F

2014-09-30

CsI, CsBr and GaAs thin films have been grown by pulsed laser deposition on glass substrates. The morphology and structure of the films have been studied using X-ray diffraction and scanning electron microscopy. The CsI and CsBr films were identical in stoichiometry to the respective targets and had a polycrystalline structure. Increasing the substrate temperature led to an increase in the density of the films. All the GaAs films differed in stoichiometry from the target. An explanation was proposed for this fact. The present results demonstrate that, when the congruent transport condition is not fulfilled, films identical in stoichiometry tomore » targets can be grown by pulsed laser deposition in the case of materials with a low melting point and thermal conductivity. (interaction of laser radiation with matter)« less

Engineering Translational Activators with CRISPR-Cas System.

PubMed

Du, Pei; Miao, Chensi; Lou, Qiuli; Wang, Zefeng; Lou, Chunbo

2016-01-15

RNA parts often serve as critical components in genetic engineering. Here we report a design of translational activators which is composed of an RNA endoribonuclease (Csy4) and two exchangeable RNA modules. Csy4, a member of Cas endoribonuclease, cleaves at a specific recognition site; this cleavage releases a cis-repressive RNA module (crRNA) from the masked ribosome binding site (RBS), which subsequently allows the downstream translation initiation. Unlike small RNA as a translational activator, the endoribonuclease-based activator is able to efficiently unfold the perfect RBS-crRNA pairing. As an exchangeable module, the crRNA-RBS duplex was forwardly and reversely engineered to modulate the dynamic range of translational activity. We further showed that Csy4 and its recognition site, together as a module, can also be replaced by orthogonal endoribonuclease-recognition site homologues. These modularly structured, high-performance translational activators would endow the programming of gene expression in the translation level with higher feasibility.

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

Pern, F. J.; Glick, S. H.

We have conducted a series of accelerated exposure test (AET) studies for various crystalline-Si (c-Si) and amorphous-Si (a-Si) cell samples that were encapsulated with different superstrates, pottants, and substrates. Nonuniform browning patterns of ethylene vinyl acetate (EVA) pottants were observed for glass/EVA/glass-encapsulated c-Si cell samples under solar simulator exposures at elevated temperatures. The polymer/polymer-configured laminates with Tedlar or Tefzel did not discolor because of photobleaching reactions, but yellowed with polyester or nylon top films. Delamination was observed for the polyester/EVA layers on a-Si minimodules and for a polyolefin-based thermoplastic pottant at high temperatures. For all tested c-Si cell samples, irregularmore » changes in the current-voltage parameters were observed that could not be accounted for simply by the transmittance changes of the superstrate/pottant layers. Silicone-type adhesives used under UV-transmitting polymer top films were observed to cause greater cell current/efficiency loss than EVA or polyethylene pottants.« less

Industrial Internet of Things-Based Collaborative Sensing Intelligence: Framework and Research Challenges.

PubMed

Chen, Yuanfang; Lee, Gyu Myoung; Shu, Lei; Crespi, Noel

2016-02-06

The development of an efficient and cost-effective solution to solve a complex problem (e.g., dynamic detection of toxic gases) is an important research issue in the industrial applications of the Internet of Things (IoT). An industrial intelligent ecosystem enables the collection of massive data from the various devices (e.g., sensor-embedded wireless devices) dynamically collaborating with humans. Effectively collaborative analytics based on the collected massive data from humans and devices is quite essential to improve the efficiency of industrial production/service. In this study, we propose a collaborative sensing intelligence (CSI) framework, combining collaborative intelligence and industrial sensing intelligence. The proposed CSI facilitates the cooperativity of analytics with integrating massive spatio-temporal data from different sources and time points. To deploy the CSI for achieving intelligent and efficient industrial production/service, the key challenges and open issues are discussed, as well.

Fabricating metal-oxide-semiconductor field-effect transistors on a polyethylene terephthalate substrate by applying low-temperature layer transfer of a single-crystalline silicon layer by meniscus force

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

Sakaike, Kohei; Akazawa, Muneki; Nakamura, Shogo

2013-12-02

A low-temperature local-layer technique for transferring a single-crystalline silicon (c-Si) film by using a meniscus force was proposed, and an n-channel metal-oxide-semiconductor field-effect transistor (MOSFET) was fabricated on polyethylene terephthalate (PET) substrate. It was demonstrated that it is possible to transfer and form c-Si films in the required shape at the required position on PET substrates at extremely low temperatures by utilizing a meniscus force. The proposed technique for layer transfer was applied for fabricating high-performance c-Si MOSFETs on a PET substrate. The fabricated MOSFET showed a high on/off ratio of more than 10{sup 8} and a high field-effect mobilitymore » of 609 cm{sup 2} V{sup −1} s{sup −1}.« less

Industrial Internet of Things-Based Collaborative Sensing Intelligence: Framework and Research Challenges

PubMed Central

Chen, Yuanfang; Lee, Gyu Myoung; Shu, Lei; Crespi, Noel

2016-01-01

The development of an efficient and cost-effective solution to solve a complex problem (e.g., dynamic detection of toxic gases) is an important research issue in the industrial applications of the Internet of Things (IoT). An industrial intelligent ecosystem enables the collection of massive data from the various devices (e.g., sensor-embedded wireless devices) dynamically collaborating with humans. Effectively collaborative analytics based on the collected massive data from humans and devices is quite essential to improve the efficiency of industrial production/service. In this study, we propose a collaborative sensing intelligence (CSI) framework, combining collaborative intelligence and industrial sensing intelligence. The proposed CSI facilitates the cooperativity of analytics with integrating massive spatio-temporal data from different sources and time points. To deploy the CSI for achieving intelligent and efficient industrial production/service, the key challenges and open issues are discussed, as well. PMID:26861345

Nicotine is a potent blocker of the cardiac A-type K(+) channels. Effects on cloned Kv4.3 channels and native transient outward current.

PubMed

Wang, H; Shi, H; Zhang, L; Pourrier, M; Yang, B; Nattel, S; Wang, Z

2000-09-05

Nicotine is a main constituent of cigarette smoke and smokeless tobacco, known to increase the risk of sudden cardiac death. This study aimed at establishing ionic mechanisms underlying potential electrophysiological effects of nicotine. Effects of nicotine on Kv4.3 and Kv4.2 channels expressed in Xenopus oocytes were studied at the whole-cell and single-channel levels. The effects of nicotine on the transient outward K(+) current (I:(to)) were studied by use of whole-cell patch-clamp techniques in canine ventricular myocytes. Nicotine potently inhibited Kv4 current. The concentration for half-maximal inhibition (IC(50)) was 40+/-4 nmol/L, and the current was abolished by 100 micromol/L nicotine. The IC(50) for block of native I:(to) was 270+/-43 nmol/L. The steady-state activation properties of Kv4.3 and I:(to) were unaltered by nicotine, whereas positive shifts of the inactivation curves were observed. Of the total inhibition of Kv4.3 and I:(to) by nicotine, 40% was due to tonic block and 60% was attributable to use-dependent block. Activation, inactivation, and reactivation kinetics were not significantly changed by nicotine. Nicotine reduced single-channel conductance, open probability, and open time but increased the closed time of Kv4.3. The effects of nicotine were not altered by antagonists to various neurotransmitter receptors, indicating direct effects on I:(to) channels. Nicotine is a potent inhibitor of cardiac A-type K(+) channels, with blockade probably due to block of closed and open channels. This action may contribute to the ability of nicotine to affect cardiac electrophysiology and induce arrhythmias.

Interactions among DIV voltage-sensor movement, fast inactivation, and resurgent Na current induced by the NaVβ4 open-channel blocking peptide

PubMed Central

Lewis, Amanda H.

2013-01-01

Resurgent Na current flows as voltage-gated Na channels recover through open states from block by an endogenous open-channel blocking protein, such as the NaVβ4 subunit. The open-channel blocker and fast-inactivation gate apparently compete directly, as slowing the onset of fast inactivation increases resurgent currents by favoring binding of the blocker. Here, we tested whether open-channel block is also sensitive to deployment of the DIV voltage sensor, which facilitates fast inactivation. We expressed NaV1.4 channels in HEK293t cells and assessed block by a free peptide replicating the cytoplasmic tail of NaVβ4 (the “β4 peptide”). Macroscopic fast inactivation was disrupted by mutations of DIS6 (L443C/A444W; “CW” channels), which reduce fast-inactivation gate binding, and/or by the site-3 toxin ATX-II, which interferes with DIV movement. In wild-type channels, the β4 peptide competed poorly with fast inactivation, but block was enhanced by ATX. With the CW mutation, large peptide-induced resurgent currents were present even without ATX, consistent with increased open-channel block upon depolarization and slower deactivation after blocker unbinding upon repolarization. The addition of ATX greatly increased transient current amplitudes and further enlarged resurgent currents, suggesting that pore access by the blocker is actually decreased by full deployment of the DIV voltage sensor. ATX accelerated recovery from block at hyperpolarized potentials, however, suggesting that the peptide unbinds more readily when DIV voltage-sensor deployment is disrupted. These results are consistent with two open states in Na channels, dependent on the DIV voltage-sensor position, which differ in affinity for the blocking protein. PMID:23940261

Endotoxin inactivation via steam-heat treatment in dilute simethicone emulsions used in biopharmaceutical processes.

PubMed

Britt, Keith A; Galvin, Jeffrey; Gammell, Patrick; Nti-Gyabaah, Joseph; Boras, George; Kolwyck, David; Ramirez, José G; Presente, Esther; Naugle, Gregory

2014-01-01

Simethicone emulsion is used to regulate foaming in cell culture operations in biopharmaceutical processes. It is also a potential source of endotoxin contamination. The inactivation of endotoxins in dilute simethicone emulsions was assessed as a function of time at different steam temperatures using a Limulus amebocyte lysate kinetic chromogenic technique. Endotoxin inactivation from steam-heat treatment was fit to a four-parameter double exponential decay model, which indicated that endotoxin inactivation was biphasic, consisting of fast and slow regimes. In the fast regime, temperature-related effects were dominant. Transitioning into the slow regime, the observed temperature dependence diminished, and concentration-related effects became increasingly significant. The change in the Gibbs free energy moving through the transition state indicated that a large energy barrier must be overcome for endotoxin inactivation to occur. The corresponding Arrhenius pre-exponential factor was >10(12) s(-1) suggesting that endotoxins in aqueous solution exist as aggregates. The disorder associated with the endotoxin inactivation reaction pathway was assessed via the change in entropy moving through the transition state. This quantity was positive indicating that endotoxin inactivation may result from hydrolysis of individual endotoxin molecules, which perturbs the conformation of endotoxin aggregates, thereby modulating the biological activity observed. Steam-heat treatment decreased endotoxin levels by 1-2 logarithm (log) reduction (LRV), which may be practically relevant depending on incoming raw material endotoxin levels. Antifoam efficiency and cell culture performance were negligibly impacted following steam-heat treatment. The results from this study show that steam-heat treatment is a viable endotoxin control strategy that can be implemented to support large-scale biopharmaceutical manufacturing. © 2014 American Institute of Chemical Engineers.

Thermal inactivation of alkali phosphatases under various conditions

NASA Astrophysics Data System (ADS)

Atyaksheva, L. F.; Tarasevich, B. N.; Chukhrai, E. S.; Poltorak, O. M.

2009-02-01

The thermal inactivation of alkali phosphatases from bacteria Escherichia coli (ECAP), bovine intestines (bovine IAP), and chicken intestines (chicken IAP) was studied in different buffer solutions and in the solid state. The conclusion was made that these enzymes had maximum stability in the solid state, and, in a carbonate buffer solution, their activity decreased most rapidly. It was found that the bacterial enzyme was more stable than animal phosphatases. It was noted that, for ECAP, four intermediate stages preceded the loss of enzyme activity, and, for bovine and chicken IAPs, three intermediate stages were observed. The activation energy of thermal inactivation of ECAP over the range 25-70°C was determined to be 80 kJ/mol; it corresponded to the dissociation of active dimers into inactive monomers. Higher activation energies (˜200 kJ/mol) observed at the initial stage of thermal inactivation of animal phosphatases resulted from the simultaneous loss of enzyme activity caused by dimer dissociation and denaturation. It was shown that the activation energy of denaturation of monomeric animal alkali phosphatases ranged from 330 to 380 kJ/mol depending on buffer media. It was concluded that the inactivation of solid samples of alkali phosphatases at 95°C was accompanied by an about twofold decrease in the content of β structures in protein molecules.

Two Components of Voltage-Dependent Inactivation in Cav1.2 Channels Revealed by Its Gating Currents

PubMed Central

Ferreira, Gonzalo; Ríos, Eduardo; Reyes, Nicolás

2003-01-01

Voltage-dependent inactivation (VDI) was studied through its effects on the voltage sensor in Cav1.2 channels expressed in tsA 201 cells. Two kinetically distinct phases of VDI in onset and recovery suggest the presence of dual VDI processes. Upon increasing duration of conditioning depolarizations, the half-distribution potential (V1/2) of intramembranous mobile charge was negatively shifted as a sum of two exponential terms, with time constants 0.5 s and 4 s, and relative amplitudes near 50% each. This kinetics behavior was consistent with that of increment of maximal charge related to inactivation (Qn). Recovery from inactivation was also accompanied by a reduction of Qn that varied with recovery time as a sum of two exponentials. The amplitudes of corresponding exponential terms were strongly correlated in onset and recovery, indicating that channels recover rapidly from fast VDI and slowly from slow VDI. Similar to charge “immobilization,” the charge moved in the repolarization (OFF) transient became slower during onset of fast VDI. Slow VDI had, instead, hallmarks of interconversion of charge. Confirming the mechanistic duality, fast VDI virtually disappeared when Li+ carried the current. A nine-state model with parallel fast and slow inactivation pathways from the open state reproduces most of the observations. PMID:12770874

Inactivation of the cloned potassium channel mouse Kv1.1 by the human Kv3.4 'ball' peptide and its chemical modification.

PubMed Central

Stephens, G J; Robertson, B

1995-01-01

1. This study used the whole-cell patch clamp technique to investigate the action of a 28-mer 'inactivation peptide' based on part of the N-terminal sequence of the human Kv3.4 K+ channel (hKv3.4 peptide) on the cloned mouse brain K+ channel mKv1.1 expressed in Chinese hamster ovary (CHO) cells, and compared this with the inactivation produced by Shaker B inactivation peptide (ShB peptide). 2. Inclusion of the hKv3.4 peptide in the patch electrode (320 microM) transformed non-inactivating mKv1.1 into a rapidly inactivating current. The voltage dependence of time constants of decay and steady-state inactivation induced by hKv3.4 peptide were characteristic of an 'A-type' K+ current. 3. The hKv3.4 peptide had no effect on the voltage dependence of activation of mKv1.1, with a mid-point of activation of -8 mV, and a slope factor of 15 mV. Steady-state inactivation curves had a mid-point of inactivation of -36 mV and a slope factor of -7 mV; the time constant of recovery from inactivation at -90 mV was 1.3 s. 4. The chemical modification reagents N-bromoacetamide (NBA, 100 microM) and chloramine-T (CL-T, 500 microM) had no effect on the fast inactivation of mKv1.1 induced by ShB peptide. In contrast, the inactivation caused by hKv3.4 peptide was removed by brief exposure to NBA and CL-T. 5. Chemical modification resulted in a hyperpolarizing shift of -8 mV (CL-T) and -11 mV (NBA) in the voltage dependence of activation of mKv1.1 in the presence of hKv3.4 peptide. 6. Chemical modification was critically dependent on the presence of a cysteine residue at position 6, and not position 24, of hKv3.4 peptide. 7. NBA and CL-T caused only a slight inhibition of unmodified mKv1.1 current with no significant effect on the voltage dependence of mKv1.1 activation, and also had no effect on channel deactivation at -90 mV. 8. Chemical modification experiments were consistent with a selective action on the hKv3.4 peptide itself, specifically at the cysteine residue at position 6. PMID:7602512

Intermittent muscle activity in the feedback loop of postural control system during natural quiet standing.

PubMed

Tanabe, Hiroko; Fujii, Keisuke; Kouzaki, Motoki

2017-09-06

The origin of continual body oscillation during quiet standing is a neural-muscular-skeletal closed feedback loop system that includes insufficient joint stiffness and a time delay. Thus, muscle activity and joint oscillations are nonlinear during quiet standing, making it difficult to demonstrate the muscular-skeletal relationship experimentally. Here we experimentally revealed this relationship using intermittent control theory, in which non-actuation works to stabilize the skeletal system towards equilibrium. We found that leg muscles were activated/inactivated when the state point was located in the opposite/same direction as the direction of anatomical action, which was associated with joint torque actuating the body towards equilibrium. The derivative values of stability index defined in the phase space approximately 200 ms before muscle inactivation were also larger than those before activation for some muscles. These results indicate that bipedal standing might be achieved by monitoring the rate of change of stability/instability components and generating joint torque to stabilize the body. In conclusion, muscles are likely to activate in an event-driven manner during quiet standing and a possible metric for on/off switching is SI dot, and our methodology of EMG processing could allows us to extract such event-driven intermittent muscle activities.

Differential Mechanism of Escherichia coli Inactivation by (+)-Limonene as a Function of Cell Physiological State and Drug's Concentration

PubMed Central

Chueca, Beatriz; Pagán, Rafael; García-Gonzalo, Diego

2014-01-01

(+)-limonene is a lipophilic antimicrobial compound, extracted from citrus fruits' essential oils, that is used as a flavouring agent and organic solvent by the food industry. A recent study has proposed a common and controversial mechanism of cell death for bactericidal antibiotics, in which hydroxyl radicals ultimately inactivated cells. Our objective was to determine whether the mechanism of Escherichia coli MG1655 inactivation by (+)-limonene follows that of bactericidal antibiotics. A treatment with 2,000 μL/L (+)-limonene inactivated 4 log10 cycles of exponentially growing E. coli cells in 3 hours. On one hand, an increase of cell survival in the ΔacnB mutant (deficient in a TCA cycle enzyme), or in the presence of 2,2′-dipyridyl (inhibitor of Fenton reaction by iron chelation), thiourea, or cysteamine (hydroxyl radical scavengers) was observed. Moreover, the ΔrecA mutant (deficient in an enzyme involved in SOS response to DNA damage) was more sensitive to (+)-limonene. Thus, this indirect evidence indicates that the mechanism of exponentially growing E. coli cells inactivation by 2,000 μL/L (+)-limonene is due to the TCA cycle and Fenton-mediated hydroxyl radical formation that caused oxidative DNA damage, as observed for bactericidal drugs. However, several differences have been observed between the proposed mechanism for bactericidal drugs and for (+)-limonene. In this regard, our results demonstrated that E. coli inactivation was influenced by its physiological state and the drug's concentration: experiments with stationary-phase cells or 4,000 μL/L (+)-limonene uncovered a different mechanism of cell death, likely unrelated to hydroxyl radicals. Our research has also shown that drug's concentration is an important factor influencing the mechanism of bacterial inactivation by antibiotics, such as kanamycin. These results might help in improving and spreading the use of (+)-limonene as an antimicrobial compound, and in clarifying the controversy about the mechanism of inactivation by bactericidal antibiotics. PMID:24705541

Differential mechanism of Escherichia coli Inactivation by (+)-limonene as a function of cell physiological state and drug's concentration.

PubMed

Chueca, Beatriz; Pagán, Rafael; García-Gonzalo, Diego

2014-01-01

(+)-limonene is a lipophilic antimicrobial compound, extracted from citrus fruits' essential oils, that is used as a flavouring agent and organic solvent by the food industry. A recent study has proposed a common and controversial mechanism of cell death for bactericidal antibiotics, in which hydroxyl radicals ultimately inactivated cells. Our objective was to determine whether the mechanism of Escherichia coli MG1655 inactivation by (+)-limonene follows that of bactericidal antibiotics. A treatment with 2,000 μL/L (+)-limonene inactivated 4 log10 cycles of exponentially growing E. coli cells in 3 hours. On one hand, an increase of cell survival in the ΔacnB mutant (deficient in a TCA cycle enzyme), or in the presence of 2,2'-dipyridyl (inhibitor of Fenton reaction by iron chelation), thiourea, or cysteamine (hydroxyl radical scavengers) was observed. Moreover, the ΔrecA mutant (deficient in an enzyme involved in SOS response to DNA damage) was more sensitive to (+)-limonene. Thus, this indirect evidence indicates that the mechanism of exponentially growing E. coli cells inactivation by 2,000 μL/L (+)-limonene is due to the TCA cycle and Fenton-mediated hydroxyl radical formation that caused oxidative DNA damage, as observed for bactericidal drugs. However, several differences have been observed between the proposed mechanism for bactericidal drugs and for (+)-limonene. In this regard, our results demonstrated that E. coli inactivation was influenced by its physiological state and the drug's concentration: experiments with stationary-phase cells or 4,000 μL/L (+)-limonene uncovered a different mechanism of cell death, likely unrelated to hydroxyl radicals. Our research has also shown that drug's concentration is an important factor influencing the mechanism of bacterial inactivation by antibiotics, such as kanamycin. These results might help in improving and spreading the use of (+)-limonene as an antimicrobial compound, and in clarifying the controversy about the mechanism of inactivation by bactericidal antibiotics.

Postponed Is Not Canceled: Role of Craniospinal Radiation Therapy in the Management of Recurrent Infant Medulloblastoma—An Experience From the HIT-REZ 1997 and 2005 Studies

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

Müller, Klaus, E-mail: Klaus.Mueller@medizin.uni-leipzig.de; Mynarek, Martin; Zwiener, Isabella

2014-04-01

Purpose: To evaluate the efficacy of craniospinal irradiation (CSI) in the management of recurrent infant medulloblastoma after surgery and chemotherapy alone. Methods and Materials: Seventeen pediatric medulloblastoma patients registered in the HIT-REZ 1997 and 2005 studies underwent CSI as salvage treatment at first recurrence. All patients had achieved complete remission after first-line treatment consisting of surgery and chemotherapy. Eleven patients showed metastatic disease at relapse. Five patients underwent surgery prior to radiation therapy, which resulted in complete resection in 1 case. In 1 patient, complete resection of the residual tumor was performed after CSI. Eleven patients received chemotherapy prior, 6 patientsmore » during and 8 patients after CSI. All patients received CSI with a median total dose of 35.2 Gy, and all but 1 received a boost to the posterior fossa (median total dose, 55.0 Gy). Metastases were boosted with an individual radiation dose, depending on their location and extent. Results: During a median follow-up time of 6.2 years since recurrence, 11 patients showed progressive disease and died. Median progression-free (overall) survival was 2.9 ± 1.1 (3.8 ± 0.8) years. Progression-free survival (PFS) rates at 1, 3, and 5 years were 88% ± 8%, 46% ± 12%, and 40% ± 12%, respectively. Overall survival (OS) rates at 1, 3, and 5 years were 94% ± 6%, 58% ± 12%, and 39% ± 12%, respectively. For 11 patients with classic medulloblastoma, 3-year (and 5-year) PFS and OS were 62% ± 15% and 72% ± 14% (52% ± 16% and 51% ± 16%), respectively. On univariate analysis, metastatic disease was not associated with poorer progression-free and overall survival. Conclusions: Our results suggest that salvage treatment of relapsed medulloblastomas consisting of CSI and chemotherapy offers a second chance for cure, even for patients with classic histological findings. Metastatic disease at relapse did not have an impact on survival. However, this may be explained by the small number of patients.« less

A study of variable thrust, variable specific impulse trajectories for solar system exploration

NASA Astrophysics Data System (ADS)

Sakai, Tadashi

A study has been performed to determine the advantages and disadvantages of variable thrust and variable Isp (specific impulse) trajectories for solar system exploration. There have been several numerical research efforts for variable thrust, variable Isp, power-limited trajectory optimization problems. All of these results conclude that variable thrust, variable Isp (variable specific impulse, or VSI) engines are superior to constant thrust, constant Isp (constant specific impulse; or CSI) engines. However, most of these research efforts assume a mission from Earth to Mars, and some of them further assume that these planets are circular and coplanar. Hence they still lack the generality. This research has been conducted to answer the following questions: (1) Is a VSI engine always better than a CSI engine or a high thrust engine for any mission to any planet with any time of flight considering lower propellant mass as the sole criterion? (2) If a planetary swing-by is used for a VSI trajectory, is the fuel savings of a VSI swing-by trajectory better than that of a CSI swing-by or high thrust swing-by trajectory? To support this research, an unique, new computer-based interplanetary trajectory calculation program has been created. This program utilizes a calculus of variations algorithm to perform overall optimization of thrust, Isp, and thrust vector direction along a trajectory that minimizes fuel consumption for interplanetary travel. It is assumed that the propulsion system is power-limited, and thus the compromise between thrust and Isp is a variable to be optimized along the flight path. This program is capable of optimizing not only variable thrust trajectories but also constant thrust trajectories in 3-D space using a planetary ephemeris database. It is also capable of conducting planetary swing-bys. Using this program, various Earth-originating trajectories have been investigated and the optimized results have been compared to traditional CSI and high thrust trajectory solutions. Results show that VSI rocket engines reduce fuel requirements for any mission compared to CSI rocket engines. Fuel can be saved by applying swing-by maneuvers for VSI engines; but the effects of swing-bys due to VSI engines are smaller than that of CSI or high thrust engines.

Chronic social instability increases anxiety-like behavior and ethanol preference in male Long Evans rats.

PubMed

Roeckner, Alyssa R; Bowling, Alexandra; Butler, Tracy R

2017-05-01

Chronic stress during adolescence is related to increased prevalence of anxiety disorders and alcohol use disorders in humans. This phenotype has been consistently recapitulated in animal models with male subjects, but models using female subjects are fewer. The aim of these studies was to test the hypothesis that chronic social instability (CSI) during adolescence engenders increased anxiety-like behavior, increased corticosterone, and greater ethanol intake and/or preference than control groups in male and female rats. A chronic social instability (CSI) procedure was conducted in separate cohorts of female and male adolescent Long Evans rats. CSI included daily social isolation for 1h, and then pair housing with a novel cage mate for 23h until the next 1h isolation period from PND 30-46. Control groups included social stability (SS), chronic isolation (ISO), and acute social instability (aSI). At PND 49-50, anxiety-like behavior was assessed on the elevated plus maze, and on PND 51 tails bloods were obtained for determination of corticosterone (CORT) levels. This was followed by 4weeks of ethanol drinking in a home cage intermittent access ethanol drinking paradigm (PND 55-81 for males, PND 57-83 for females). Planned contrast testing showed that the male CSI group had greater anxiety-like behavior compared controls, but group differences were not apparent for CORT. CSI males had significantly higher levels of ethanol preference during drinking weeks 2-3 compared to all other groups and compared to SS and ISO groups in week 4. For the female cohort, we did not observe consistent group differences in anxiety-like behavior, CORT levels were unexpectedly lower in the ISO group only compared to the other groups, and group differences were not apparent for ethanol intake/preference. In conclusion, chronic stress during adolescence in the form of social instability increases anxiety-like behavior and ethanol preference in male rats, consistent with other models of chronic stress during adolescence. Conversely, and contrary to our hypothesis, female rats' anxiety-like behavior, CORT level, and ethanol intake/preference were not altered by CSI. New paradigms must continue to be explored for study of clinically relevant relationships in female preclinical models. Copyright © 2017 Elsevier Inc. All rights reserved.

High pressure thermal inactivation of Clostridium botulinum type E endospores – kinetic modeling and mechanistic insights

PubMed Central

Lenz, Christian A.; Reineke, Kai; Knorr, Dietrich; Vogel, Rudi F.

2015-01-01

Cold-tolerant, neurotoxigenic, endospore forming Clostridium (C.) botulinum type E belongs to the non-proteolytic physiological C. botulinum group II, is primarily associated with aquatic environments, and presents a safety risk for seafood. High pressure thermal (HPT) processing exploiting the synergistic effect of pressure and temperature can be used to inactivate bacterial endospores. We investigated the inactivation of C. botulinum type E spores by (near) isothermal HPT treatments at 300–1200 MPa at 30–75°C for 1 s to 10 min. The occurrence of heat and lysozyme susceptible spore fractions after such treatments was determined. The experimental data were modeled to obtain kinetic parameters and represented graphically by isoeffect lines. In contrast to findings for spores of other species and within the range of treatment parameters applied, zones of spore stabilization (lower inactivation than heat treatments alone), large heat susceptible (HPT-induced germinated) or lysozyme-dependently germinable (damaged coat layer) spore fractions were not detected. Inactivation followed first order kinetics. Dipicolinic acid release kinetics allowed for insights into possible inactivation mechanisms suggesting a (poorly effective) physiologic-like (similar to nutrient-induced) germination at ≤450 MPa/≤45°C and non-physiological germination at >500 MPa/>60–70°C. Results of this study support the existence of some commonalities in the HPT inactivation mechanism of C. botulinum type E spores and Bacillus spores although both organisms have significantly different HPT resistance properties. The information presented here contributes to closing the gap in knowledge regarding the HPT inactivation of spore formers relevant to food safety and may help industrial implementation of HPT processing. The markedly lower HPT resistance of C. botulinum type E spores compared with the resistance of spores from other C. botulinum types could allow for the implementation of milder processes without endangering food safety. PMID:26191048

Rare Kaon Decays, KEK experiment E391 and E14 at the Japan Physics and Accelerator Research Complex (J-PARC)

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

Wah, Yau Wai

2012-12-06

The goal of the J-PARC neutral kaon experiment (E14/KOTO) is to discover and measure the rate of the kaon rare decay to pi-zero and two neutrinos. This flavor changing neutral current decay proceeds through second-order weak interactions. Other, as yet undiscovered particles, which can mediate the decay could provide an enhancement (or depletion) to the branching ratio which in the Standard Model is accurately predicted within a few percent to be 2.8x10-11. The experiment is designed to observe more than 100 events at the Standard Model branching. It is a follow-up of the KEK E391a experiment and has stage-2 approvalmore » by J-PARC PAC in 2007. E14/KOTO has collaborators from Japan (Kyoto, Osaka, Yamagata, Saga), US (Arizona State, Chicago, Michigan Ann Arbor), Taiwan (National Taiwan), Korea, and Russia (Dubna). The experiment exploits the 300kW 30-50 GeV proton delivery of the J-PARC accelerator with a hermetic high acceptance detector with a fine grained Cesium Iodide (CsI) crystal calorimeter, and state of the art electronic front end and data acquisition system. With the recovery of the tsunami disaster on March 11th 2011, E14 is scheduled to start collecting data in December 2012. During the detector construction phase, Chicago focuses on the front end electronics readout of the entire detector system, particularly the CsI calorimeter. The CsI crystals together with its photomultipliers were previously used at the Fermilab KTeV experiment (E832/E799), and were loaned to E14 via this Chicago DOE support. The new readout electronics includes an innovative 10-pole pulse-shaping technique coupled with high speed digitization (14-bit 125MHz and 12-bit 500MHz). This new instrument enables us to measure both energy and timing, particularly with timing resolution better than 100 psec. Besides the cost saving by elimination of the standard time to digital converters, it is now possible to measure the momenta of the final state photons for additional background suppression. Chicago also designed and built several technically difficult hardware items including the vacuum cable feed-through (for a total of 3500 channels); special 50 ohm single-ended signal to 100 ohm differential signal converters; and last but not least, the recommendations on the selection of the differential signal cables for all detector elements to eliminate ground loops while maintaining signal fidelity.« less

An adaptation method to improve secret key rates of time-frequency QKD in atmospheric turbulence channels

NASA Astrophysics Data System (ADS)

Sun, Xiaole; Djordjevic, Ivan B.; Neifeld, Mark A.

2016-03-01

Free-space optical (FSO) channels can be characterized by random power fluctuations due to atmospheric turbulence, which is known as scintillation. Weak coherent source based FSO quantum key distribution (QKD) systems suffer from the scintillation effect because during the deep channel fading the expected detection rate drops, which then gives an eavesdropper opportunity to get additional information about protocol by performing photon number splitting (PNS) attack and blocking single-photon pulses without changing QBER. To overcome this problem, in this paper, we study a large-alphabet QKD protocol, which is achieved by using pulse-position modulation (PPM)-like approach that utilizes the time-frequency uncertainty relation of the weak coherent photon state, called here TF-PPM-QKD protocol. We first complete finite size analysis for TF-PPM-QKD protocol to give practical bounds against non-negligible statistical fluctuation due to finite resources in practical implementations. The impact of scintillation under strong atmospheric turbulence regime is studied then. To overcome the secure key rate performance degradation of TF-PPM-QKD caused by scintillation, we propose an adaptation method for compensating the scintillation impact. By changing source intensity according to the channel state information (CSI), obtained by classical channel, the adaptation method improves the performance of QKD system with respect to the secret key rate. The CSI of a time-varying channel can be predicted using stochastic models, such as autoregressive (AR) models. Based on the channel state predictions, we change the source intensity to the optimal value to achieve a higher secret key rate. We demonstrate that the improvement of the adaptation method is dependent on the prediction accuracy.

X chromosome inactivation in human pluripotent stem cells as a model for human development: back to the drawing board?

PubMed

Geens, Mieke; Chuva De Sousa Lopes, Susana M

2017-09-01

Human pluripotent stem cells (hPSC), both embryonic and induced (hESC and hiPSC), are regarded as a valuable in vitro model for early human development. In order to fulfil this promise, it is important that these cells mimic as closely as possible the in vivo molecular events, both at the genetic and epigenetic level. One of the most important epigenetic events during early human development is X chromosome inactivation (XCI), the transcriptional silencing of one of the two X chromosomes in female cells. XCI is important for proper development and aberrant XCI has been linked to several pathologies. Recently, novel data obtained using high throughput single-cell technology during human preimplantation development have suggested that the XCI mechanism is substantially different from XCI in mouse. It has also been suggested that hPSC show higher complexity in XCI than the mouse. Here we compare the available recent data to understand whether XCI during human preimplantation can be properly recapitulated using hPSC. We will summarize what is known on the timing and mechanisms of XCI during human preimplantation development. We will compare this to the XCI patterns that are observed during hPSC derivation, culture and differentiation, and comment on the cause of the aberrant XCI patterns observed in hPSC. Finally, we will discuss the implications of the aberrant XCI patterns on the applicability of hPSC as an in vitro model for human development and as cell source for regenerative medicine. Combinations of the following keywords were applied as search criteria in the PubMed database: X chromosome inactivation, preimplantation development, embryonic stem cells, induced pluripotent stem cells, primordial germ cells, differentiation. Recent single-cell RNASeq data have shed new light on the XCI process during human preimplantation development. These indicate a gradual inactivation on both XX chromosomes, starting from Day 4 of development and followed by a random choice to inactivate one of them, instead of the mechanism in mice where imprinted XCI is followed by random XCI. We have put these new findings in perspective using previous data obtained in human (and mouse) embryos. In addition, there is an ongoing discussion whether or not hPSC lines show X chromosome reactivation upon derivation, mimicking the earliest embryonic cells, and the XCI states observed during culture of hPSC are highly variable. Recent studies have shown that hPSC rapidly progress to highly aberrant XCI patterns and that this process is probably driven by suboptimal culture conditions. Importantly, these aberrant XCI states seem to be inherited by the differentiated hPSC-progeny. The aberrant XCI states (and epigenetic instability) observed in hPSC throw a shadow on their applicability as an in vitro model for development and disease modelling. Moreover, as the aberrant XCI states observed in hPSC seem to shift to a more malignant phenotype, this may also have important consequences for the safety aspect of using hPSC in the clinic. © The Author 2017. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Sodium Magnetic Resonance Imaging of Ankle Joint in Cadaver Specimens, Volunteers, and Patients After Different Cartilage Repair Techniques at 7 T

PubMed Central

Zbýň, Štefan; Brix, Martin O.; Juras, Vladimir; Domayer, Stephan E.; Walzer, Sonja M.; Mlynarik, Vladimir; Apprich, Sebastian; Buckenmaier, Kai; Windhager, Reinhard; Trattnig, Siegfried

2015-01-01

Objectives The goal of cartilage repair techniques such as microfracture (MFX) or matrix-associated autologous chondrocyte transplantation (MACT) is to produce repair tissue (RT) with sufficient glycosaminoglycan (GAG) content. Sodium magnetic resonance imaging (MRI) offers a direct and noninvasive evaluation of the GAG content in native cartilage and RT. In the femoral cartilage, this method was able to distinguish between RTs produced by MFX and MACT having different GAG contents. However, it needs to be clarified whether sodium MRI can be useful for evaluating RT in thin ankle cartilage. Thus, the aims of this 7-T study were (1) to validate our sodium MRI protocol in cadaver ankle samples, (2) to evaluate the sodium corrected signal intensities (cSI) in cartilage of volunteers, (3) and to compare sodium values in RT between patients after MFX and MACT treatment. Materials and Methods Five human cadaver ankle samples as well as ankles of 9 asymptomatic volunteers, 6 MFX patients and 6 MACT patients were measured in this 7-T study. Sodium values from the ankle samples were compared with histochemically evaluated GAG content. In the volunteers, sodium cSI values were calculated in the cartilages of ankle and subtalar joint. In the patients, sodium cSI in RT and reference cartilage were measured, morphological appearance of RT was evaluated using the magnetic resonance observation of cartilage repair tissue (MOCART) scoring system, and clinical outcome before and after surgery was assessed using the American Orthopaedic Foot and Ankle Society score and Modified Cincinnati Knee Scale. All regions of interest were defined on morphological images and subsequently transferred to the corresponding sodium images. Analysis of variance, t tests, and Pearson correlation coefficients were evaluated. Results In the patients, significantly lower sodium cSI values were found in RT than in reference cartilage for the MFX (P = 0.007) and MACT patients (P = 0.008). Sodium cSI and MOCART scores in RT did not differ between the MFX and MACT patients (P = 0.185). No significant difference in sodium cSI was found between reference cartilage of the volunteers and the patients (P = 0.355). The patients showed significantly higher American Orthopaedic Foot and Ankle Society and Modified Cincinnati scores after treatment than they did before treatment. In the volunteers, sodium cSI was significantly higher in the tibial cartilage than in the talar cartilage of ankle joint (P = 0.002) and in the talar cartilage than in the calcaneal cartilage of subtalar joint (P < 0.001). Data from the cadaver ankle samples showed a strong linear relationship between the sodium values and the histochemically determined GAG content (r = 0.800; P < 0.001; R2 = 0.639). Conclusions This study demonstrates the feasibility of in vivo quantification of sodium cSI, which can be used for GAG content evaluation in thin cartilages of ankle and subtalar joints at 7 T. A strong correlation observed between the histochemically evaluated GAG content and the sodium values proved the sufficient sensitivity of sodium MRI to changes in the GAG content of cartilages in the ankle. Both MFX and MACT produced RT with lower sodium cSI and, thus, of lower quality compared with reference cartilage in the patients or in the volunteers. Our results suggest that MFX and MACT produce RT with similar GAG content and similar morphological appearance in patients with similar surgery outcome. Sodium MRI at 7 T allows a quantitative evaluation of RT quality in the ankle and may thus be useful in the noninvasive assessment of new cartilage repair procedures. PMID:25436618

Sodium magnetic resonance imaging of ankle joint in cadaver specimens, volunteers, and patients after different cartilage repair techniques at 7 T: initial results.

PubMed

Zbýň, Štefan; Brix, Martin O; Juras, Vladimir; Domayer, Stephan E; Walzer, Sonja M; Mlynarik, Vladimir; Apprich, Sebastian; Buckenmaier, Kai; Windhager, Reinhard; Trattnig, Siegfried

2015-04-01

The goal of cartilage repair techniques such as microfracture (MFX) or matrix-associated autologous chondrocyte transplantation (MACT) is to produce repair tissue (RT) with sufficient glycosaminoglycan (GAG) content. Sodium magnetic resonance imaging (MRI) offers a direct and noninvasive evaluation of the GAG content in native cartilage and RT. In the femoral cartilage, this method was able to distinguish between RTs produced by MFX and MACT having different GAG contents. However, it needs to be clarified whether sodium MRI can be useful for evaluating RT in thin ankle cartilage. Thus, the aims of this 7-T study were (1) to validate our sodium MRI protocol in cadaver ankle samples, (2) to evaluate the sodium corrected signal intensities (cSI) in cartilage of volunteers, (3) and to compare sodium values in RT between patients after MFX and MACT treatment. Five human cadaver ankle samples as well as ankles of 9 asymptomatic volunteers, 6 MFX patients and 6 MACT patients were measured in this 7-T study. Sodium values from the ankle samples were compared with histochemically evaluated GAG content. In the volunteers, sodium cSI values were calculated in the cartilages of ankle and subtalar joint. In the patients, sodium cSI in RT and reference cartilage were measured, morphological appearance of RT was evaluated using the magnetic resonance observation of cartilage repair tissue (MOCART) scoring system, and clinical outcome before and after surgery was assessed using the American Orthopaedic Foot and Ankle Society score and Modified Cincinnati Knee Scale. All regions of interest were defined on morphological images and subsequently transferred to the corresponding sodium images. Analysis of variance, t tests, and Pearson correlation coefficients were evaluated. In the patients, significantly lower sodium cSI values were found in RT than in reference cartilage for the MFX (P = 0.007) and MACT patients (P = 0.008). Sodium cSI and MOCART scores in RT did not differ between the MFX and MACT patients (P = 0.185). No significant difference in sodium cSI was found between reference cartilage of the volunteers and the patients (P = 0.355). The patients showed significantly higher American Orthopaedic Foot and Ankle Society and Modified Cincinnati scores after treatment than they did before treatment. In the volunteers, sodium cSI was significantly higher in the tibial cartilage than in the talar cartilage of ankle joint (P = 0.002) and in the talar cartilage than in the calcaneal cartilage of subtalar joint (P < 0.001). Data from the cadaver ankle samples showed a strong linear relationship between the sodium values and the histochemically determined GAG content (r = 0.800; P < 0.001; R = 0.639). This study demonstrates the feasibility of in vivo quantification of sodium cSI, which can be used for GAG content evaluation in thin cartilages of ankle and subtalar joints at 7 T. A strong correlation observed between the histochemically evaluated GAG content and the sodium values proved the sufficient sensitivity of sodium MRI to changes in the GAG content of cartilages in the ankle. Both MFX and MACT produced RT with lower sodium cSI and, thus, of lower quality compared with reference cartilage in the patients or in the volunteers. Our results suggest that MFX and MACT produce RT with similar GAG content and similar morphological appearance in patients with similar surgery outcome. Sodium MRI at 7 T allows a quantitative evaluation of RT quality in the ankle and may thus be useful in the noninvasive assessment of new cartilage repair procedures.

Plasticity, dynamics, and inhibition of emerging tetracycline-resistance enzymes

PubMed Central

Park, Jooyoung; Gasparrini, Andrew J.; Reck, Margaret R.; Symister, Chanez T.; Elliott, Jennifer L.; Vogel, Joseph P.; Wencewicz, Timothy A.; Dantas, Gautam; Tolia, Niraj H.

2017-01-01

While tetracyclines are an important class of antibiotics in agriculture and the clinic, their efficacy is threatened by increasing resistance. Resistance to tetracyclines can occur through efflux, ribosomal protection, or enzymatic inactivation. Surprisingly, tetracycline enzymatic inactivation has remained largely unexplored despite providing the distinct advantage of antibiotic clearance. The tetracycline destructases are a recently-discovered family of tetracycline-inactivating flavoenzymes from pathogens and soil metagenomes with a high potential for broad dissemination. Here, we show tetracycline destructases accommodate tetracycline-class antibiotics in diverse and novel orientations for catalysis, and antibiotic binding drives unprecedented structural dynamics facilitating tetracycline inactivation. We identify a key inhibitor binding mode that locks the flavin adenine dinucleotide cofactor in an inactive state, functionally rescuing tetracycline activity. Our results reveal the potential of a novel tetracycline/tetracycline destructase inhibitor combination therapy strategy to overcome resistance by enzymatic inactivation and restore the use of an important class of antibiotics. PMID:28481346

Plasticity, dynamics, and inhibition of emerging tetracycline resistance enzymes.

PubMed

Park, Jooyoung; Gasparrini, Andrew J; Reck, Margaret R; Symister, Chanez T; Elliott, Jennifer L; Vogel, Joseph P; Wencewicz, Timothy A; Dantas, Gautam; Tolia, Niraj H

2017-07-01

Although tetracyclines are an important class of antibiotics for use in agriculture and the clinic, their efficacy is threatened by increasing resistance. Resistance to tetracyclines can occur through efflux, ribosomal protection, or enzymatic inactivation. Surprisingly, tetracycline enzymatic inactivation has remained largely unexplored, despite providing the distinct advantage of antibiotic clearance. The tetracycline destructases are a recently discovered family of tetracycline-inactivating flavoenzymes from pathogens and soil metagenomes that have a high potential for broad dissemination. Here, we show that tetracycline destructases accommodate tetracycline-class antibiotics in diverse and novel orientations for catalysis, and antibiotic binding drives unprecedented structural dynamics facilitating tetracycline inactivation. We identify a key inhibitor binding mode that locks the flavin adenine dinucleotide cofactor in an inactive state, functionally rescuing tetracycline activity. Our results reveal the potential of a new tetracycline and tetracycline destructase inhibitor combination therapy strategy to overcome resistance by enzymatic inactivation and restore the use of an important class of antibiotics.