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Sample records for intrinsic phase response

  1. Intrinsic response of polymer liquid crystals in photochemical phase transition

    SciTech Connect

    Ikeda, Tomiki; Sasaki, Takeo; Kim, Haengboo )

    1991-01-24

    Time-resolved measurements were performed on the photochemically induced isothermal phase transition of polymer liquid crystals (PLC) with mesogenic side chains of phenyl benzoate (PAPB3) and cyanobiphenyl (PACB3) under conditions wherein the photochemical reaction of the doped photoresponsive molecule (4-butyl-4-{prime}-methoxyazobenzene, BMAB) was completed within {approximately} 10 ns, and the subsequent phase transition of the matrix PLC from nematic (N) to isotropic (I) state was followed by time-resolved measurements of the birefringence of the system. Formation of a sufficient amount of the cis isomer of BMAB with a single pulse of a laser lowered the N-I phase transition temperature of the mixture, inducing the N-I phase transition of PLCs isothermally in a time range of {approximately} 200 ms. This time range is comparable to that of low molecular weight liquid crystals, indicating that suppression in mobility of mesogens in PLCs does not affect significantly the thermodynamically controlled process.

  2. Adaptive Responses Limited by Intrinsic Noise

    PubMed Central

    Shankar, Prabhat; Nishikawa, Masatoshi; Shibata, Tatsuo

    2015-01-01

    Sensory systems have mechanisms to respond to the external environment and adapt to them. Such adaptive responses are effective for a wide dynamic range of sensing and perception of temporal change in stimulus. However, noise generated by the adaptation system itself as well as extrinsic noise in sensory inputs may impose a limit on the ability of adaptation systems. The relation between response and noise is well understood for equilibrium systems in the form of fluctuation response relation. However, the relation for nonequilibrium systems, including adaptive systems, are poorly understood. Here, we systematically explore such a relation between response and fluctuation in adaptation systems. We study the two network motifs, incoherent feedforward loops (iFFL) and negative feedback loops (nFBL), that can achieve perfect adaptation. We find that the response magnitude in adaption systems is limited by its intrinsic noise, implying that higher response would have higher noise component as well. Comparing the relation of response and noise in iFFL and nFBL, we show that whereas iFFL exhibits adaptation over a wider parameter range, nFBL offers higher response to noise ratio than iFFL. We also identify the condition that yields the upper limit of response for both network motifs. These results may explain the reason of why nFBL seems to be more abundant in nature for the implementation of adaption systems. PMID:26305221

  3. Active Nematics Are Intrinsically Phase Separated

    NASA Astrophysics Data System (ADS)

    Mishra, Shradha; Ramaswamy, Sriram

    2006-09-01

    Two-dimensional nonequilibrium nematic steady states, as found in agitated granular-rod monolayers or films of orientable amoeboid cells, were predicted [Europhys. Lett. 62, 196 (2003)EULEEJ0295-507510.1209/epl/i2003-00346-7] to have giant number fluctuations, with the standard deviation proportional to the mean. We show numerically that the steady state of such systems is macroscopically phase separated, yet dominated by fluctuations, as in the Das-Barma model [Phys. Rev. Lett. 85, 1602 (2000)PRLTAO0031-900710.1103/PhysRevLett.85.1602]. We suggest experimental tests of our findings in granular and living-cell systems.

  4. Quantum phases in intrinsic Josephson junctions: Quantum magnetism analogy

    NASA Astrophysics Data System (ADS)

    Machida, Masahiko; Kobayashi, Keita; Koyama, Tomio

    2013-08-01

    We explore quantum phases in intrinsic Josephson junction (IJJ) stacks, whose in-plane area is so small that the capacitive coupling has a dominant role in the superconducting phase dynamics. In such cases, the effective Hamiltonian for the superconducting phase can be mapped onto that of one-dimensional ferromagnetically-interacting spin model, whose spin length S depends on the magnitude of the on-site Coulomb repulsion. The ferromagnetic model for IJJ’s prefers synchronized quantum features in contrast to the antiferromagnetically-interacting model in the conventional Josephson junction arrays.

  5. Quasiparticle current and phase locking of intrinsic Josephson junctions

    NASA Astrophysics Data System (ADS)

    Seidel, P.; Grib, A. N.; Shukrinov, Yu. M.; Scherbel, J.; Hübner, U.; Schmidl, F.

    2001-09-01

    On the base of our experiments on thin film Josephson junctions in mesa geometry we discuss the quasiparticle branches of the intrinsic arrays within a tunnelling model using d-wave superconductor density of states. We find temperature dependent current contributions and a zero bias anomaly. The coherent behaviour is studied for intrinsic arrays with an additional side-wall shunt. The existence of thresholds of phase locking at small as well as at large inductances is demonstrated. We discuss the problems with experimental realisation of the shunts as well as with an alternative concept to enhance phase locking in such arrays towards application as oscillators in the frequency range up to some THz.

  6. Dynamic differential imaging of intrinsic optical responses in the retina

    NASA Astrophysics Data System (ADS)

    Yao, Xin-Cheng; Li, Yang-Guo; Liu, Lei; Amthor, Frank

    2010-02-01

    High resolution monitoring of stimulus-evoked retinal neural activities is important for understanding retinal neural mechanisms, and for diagnosis of retinal disease and evaluation of treatment. Fast intrinsic optical signals (IOSs), which have the time courses comparable to retinal electrophysiological responses, hold the promise for high resolution imaging of retinal neural activities. However, application of fast IOS imaging has been hindered by contamination of slow, high magnitude, optical responses associated with transient hemodynamic and metabolic changes. We recently demonstrated the feasibility of separating fast IOSs from slow optical responses by combined dynamic differential imaging and high frequency flicker stimulation.

  7. Intrinsic fluctuations and driven response of insect swarms

    NASA Astrophysics Data System (ADS)

    Ni, Rui; Puckett, James G.; Dufresne, Eric R.; Ouellette, Nicholas T.

    2015-03-01

    Much of our understanding of collective behaviour in social animals comes from passive observations of animal groups. To understand the group dynamics fully, however, we must also characterize the response of animal aggregations to disturbances. Using three-dimensional particle tracking, we study both the intrinsic fluctuations of laboratory swarms of the non-biting midge Chironomus riparius and the response of the swarms to controlled external perturbations: the amplitude-modulated sound of male midge wingbeats. Although these perturbations have an insignificant effect on the behavior of individuals, we find that they can have a strong impact on the collective movement. Intriguingly, the response of the swarm is similar reminiscent to of that of a passive equilibrium system to an external driving force, with microscopic fluctuations underlying combining to produce a macroscopic linear response over a wide range of driving frequencies.

  8. Intrinsic Fluctuations and Driven Response of Insect Swarms

    NASA Astrophysics Data System (ADS)

    Ni, Rui; Puckett, James G.; Dufresne, Eric R.; Ouellette, Nicholas T.

    2015-09-01

    Animals of all sizes form groups, as acting together can convey advantages over acting alone; thus, collective animal behavior has been identified as a promising template for designing engineered systems. However, models and observations have focused predominantly on characterizing the overall group morphology, and often focus on highly ordered groups such as bird flocks. We instead study a disorganized aggregation (an insect mating swarm), and compare its natural fluctuations with the group-level response to an external stimulus. We quantify the swarm's frequency-dependent linear response and its spectrum of intrinsic fluctuations, and show that the ratio of these two quantities has a simple scaling with frequency. Our results provide a new way of comparing models of collective behavior with experimental data.

  9. Intrinsic fluctuations and driven response of insect swarms.

    PubMed

    Ni, Rui; Puckett, James G; Dufresne, Eric R; Ouellette, Nicholas T

    2015-09-11

    Animals of all sizes form groups, as acting together can convey advantages over acting alone; thus, collective animal behavior has been identified as a promising template for designing engineered systems. However, models and observations have focused predominantly on characterizing the overall group morphology, and often focus on highly ordered groups such as bird flocks. We instead study a disorganized aggregation (an insect mating swarm), and compare its natural fluctuations with the group-level response to an external stimulus. We quantify the swarm's frequency-dependent linear response and its spectrum of intrinsic fluctuations, and show that the ratio of these two quantities has a simple scaling with frequency. Our results provide a new way of comparing models of collective behavior with experimental data. PMID:26406859

  10. Broadband macroscopic cortical oscillations emerge from intrinsic neuronal response failures.

    PubMed

    Goldental, Amir; Vardi, Roni; Sardi, Shira; Sabo, Pinhas; Kanter, Ido

    2015-01-01

    Broadband spontaneous macroscopic neural oscillations are rhythmic cortical firing which were extensively examined during the last century, however, their possible origination is still controversial. In this work we show how macroscopic oscillations emerge in solely excitatory random networks and without topological constraints. We experimentally and theoretically show that these oscillations stem from the counterintuitive underlying mechanism-the intrinsic stochastic neuronal response failures (NRFs). These NRFs, which are characterized by short-term memory, lead to cooperation among neurons, resulting in sub- or several- Hertz macroscopic oscillations which coexist with high frequency gamma oscillations. A quantitative interplay between the statistical network properties and the emerging oscillations is supported by simulations of large networks based on single-neuron in-vitro experiments and a Langevin equation describing the network dynamics. Results call for the examination of these oscillations in the presence of inhibition and external drives. PMID:26578893

  11. Broadband macroscopic cortical oscillations emerge from intrinsic neuronal response failures

    PubMed Central

    Goldental, Amir; Vardi, Roni; Sardi, Shira; Sabo, Pinhas; Kanter, Ido

    2015-01-01

    Broadband spontaneous macroscopic neural oscillations are rhythmic cortical firing which were extensively examined during the last century, however, their possible origination is still controversial. In this work we show how macroscopic oscillations emerge in solely excitatory random networks and without topological constraints. We experimentally and theoretically show that these oscillations stem from the counterintuitive underlying mechanism—the intrinsic stochastic neuronal response failures (NRFs). These NRFs, which are characterized by short-term memory, lead to cooperation among neurons, resulting in sub- or several- Hertz macroscopic oscillations which coexist with high frequency gamma oscillations. A quantitative interplay between the statistical network properties and the emerging oscillations is supported by simulations of large networks based on single-neuron in-vitro experiments and a Langevin equation describing the network dynamics. Results call for the examination of these oscillations in the presence of inhibition and external drives. PMID:26578893

  12. Critical Evaluation of Ayurvedic Plants for Stimulating Intrinsic Antioxidant Response

    PubMed Central

    Shukla, Sunil Dutt; Bhatnagar, Maheep; Khurana, Sukant

    2012-01-01

    Oxidative damage caused by free radicals plays an important role in the causation and progression of many diseases, including aging. Free-radical damage is countered by many mechanisms, including both active antioxidant enzymatic activity in our body and passive antioxidants. Antioxidant response of our body can accommodate increased oxidative damage in diseased states to a level but beyond that level, additional antioxidants are required to combat the increased stress. Apart from the regular dietary sources of antioxidants, many traditional herbal medicines demonstrate a potential to boost antioxidant activity. Rasayana chikitsa that deals with rejuvenation and revitalization is a branch of the Indian traditional medical system of ayurveda. We review some select herbs described in rasayana chikitsa that have been assessed by modern means for stimulating intrinsic antioxidant responses in humans. A critical evaluation of rasayana chikitsa will likely provide urgently needed, actual stimulants of our physiological antioxidant responses and not just more passive antioxidants to add to an already large catalog. PMID:22855669

  13. Gas-phase NMR studies of alcohols. Intrinsic acidities

    NASA Astrophysics Data System (ADS)

    Chauvel, J. Paul; True, Nancy S.

    1985-05-01

    Gas-phase (≈100 Torr) 1H NMR spectra of eighteen simple aliphatic and unsaturated alcohols, four fluorinated alcohols, and two thiols were obtained at 148.6°C where hydrogen bonding has little effect on chemical shifts. For the methanol, ethanol, n-propanol, i-propanol, t-butanol, i- butanol, neopentanol, 2,2,2-trifluoroethanol and benzyl alcohol, the observed hydroxylic proton chemical shifts correlate with previously obtained relative gas-phase acidities from thermochemical analysis which employed equilibrium constants of proton transfer reactions measured via mass spectroscopic and ion cyclotron resonance techniques. The correlational dependence is 10.3(0.5) kcal/mol ppm with a correlation coefficient of 0.99. These results demonstrate that the trend of increasing acidity with increasing size of the alkyl substituent is also reflected in the neutral forms of the alcohols, indicating that the polarizability of the ionic forms is not the only determining factor in relative gas-phase acidities of alcohols. Although factors affecting the hydroxylic proton chemical shifts of the larger substituted and unsaturated alcohols are more complex, their observed 1H NMR spectra also reflect this trend. For methanol and ethanol observed gas-phase 1H chemical shifts are also compared with recent theoritical calculations. 3JHH coupling constants across CO bonds are ≈ 5.5 Hz, significantly smaller than typical 3JHH coupling across sp 3 hybrid C C bonds.

  14. Intrinsic Spin Hall Effect Induced by Quantum Phase Transition in HgCdTe Quantum Wells

    SciTech Connect

    Yang, Wen; Chang, Kai; Zhang, Shou-Cheng; /Stanford U., Phys. Dept.

    2010-03-19

    Spin Hall effect can be induced both by the extrinsic impurity scattering and by the intrinsic spin-orbit coupling in the electronic structure. The HgTe/CdTe quantum well has a quantum phase transition where the electronic structure changes from normal to inverted. We show that the intrinsic spin Hall effect of the conduction band vanishes on the normal side, while it is finite on the inverted side. This difference gives a direct mechanism to experimentally distinguish the intrinsic spin Hall effect from the extrinsic one.

  15. Polymerase chain reaction with phase change as intrinsic thermal control

    NASA Astrophysics Data System (ADS)

    Hsieh, Yi-Fan; Yonezawa, Eri; Kuo, Long-Sheng; Yeh, Shiou-Hwei; Chen, Pei-Jer; Chen, Ping-Hei

    2013-04-01

    This research demonstrated that without any external temperature controller, the capillary convective polymerase chain reaction (ccPCR) powered by a candle can operate with the help of phase change. The candle ccPCR system productively amplified hepatitis B virus 122 base-pairs DNA fragment. The detection sensitivity can achieve at an initial DNA concentration to 5 copies per reaction. The results also show that the candle ccPCR system can operate functionally even the ambient temperature varies from 7 °C to 45 °C. These features imply that the candle ccPCR system can provide robust medical detection services.

  16. Plastic Change along the Intact Crossed Pathway in Acute Phase of Cerebral Ischemia Revealed by Optical Intrinsic Signal Imaging

    PubMed Central

    Guo, Xiaoli; He, Yongzhi; Lu, Hongyang; Li, Yao; Su, Xin; Jiang, Ying; Tong, Shanbao

    2016-01-01

    The intact crossed pathway via which the contralesional hemisphere responds to the ipsilesional somatosensory input has shown to be affected by unilateral stroke. The aim of this study was to investigate the plasticity of the intact crossed pathway in response to different intensities of stimulation in a rodent photothrombotic stroke model. Using optical intrinsic signal imaging, an overall increase of the contralesional cortical response was observed in the acute phase (≤48 hours) after stroke. In particular, the contralesional hyperactivation is more prominent under weak stimulations, while a strong stimulation would even elicit a depressed response. The results suggest a distinct stimulation-response pattern along the intact crossed pathway after stroke. We speculate that the contralesional hyperactivation under weak stimulations was due to the reorganization for compensatory response to the weak ipsilateral somatosensory input. PMID:27144032

  17. Sequence heuristics to encode phase behaviour in intrinsically disordered protein polymers

    PubMed Central

    Quiroz, Felipe García; Chilkoti, Ashutosh

    2015-01-01

    Proteins and synthetic polymers that undergo aqueous phase transitions mediate self-assembly in nature and in man-made material systems. Yet little is known about how the phase behaviour of a protein is encoded in its amino acid sequence. Here, by synthesizing intrinsically disordered, repeat proteins to test motifs that we hypothesized would encode phase behaviour, we show that the proteins can be designed to exhibit tunable lower or upper critical solution temperature (LCST and UCST, respectively) transitions in physiological solutions. We also show that mutation of key residues at the repeat level abolishes phase behaviour or encodes an orthogonal transition. Furthermore, we provide heuristics to identify, at the proteome level, proteins that might exhibit phase behaviour and to design novel protein polymers consisting of biologically active peptide repeats that exhibit LCST or UCST transitions. These findings set the foundation for the prediction and encoding of phase behaviour at the sequence level. PMID:26390327

  18. Sequence heuristics to encode phase behaviour in intrinsically disordered protein polymers.

    PubMed

    Quiroz, Felipe García; Chilkoti, Ashutosh

    2015-11-01

    Proteins and synthetic polymers that undergo aqueous phase transitions mediate self-assembly in nature and in man-made material systems. Yet little is known about how the phase behaviour of a protein is encoded in its amino acid sequence. Here, by synthesizing intrinsically disordered, repeat proteins to test motifs that we hypothesized would encode phase behaviour, we show that the proteins can be designed to exhibit tunable lower or upper critical solution temperature (LCST and UCST, respectively) transitions in physiological solutions. We also show that mutation of key residues at the repeat level abolishes phase behaviour or encodes an orthogonal transition. Furthermore, we provide heuristics to identify, at the proteome level, proteins that might exhibit phase behaviour and to design novel protein polymers consisting of biologically active peptide repeats that exhibit LCST or UCST transitions. These findings set the foundation for the prediction and encoding of phase behaviour at the sequence level.

  19. Development of a gas-phase stereochemical protocol. Intrinsic diastereoselectivity in hydride reductions of cyclohexanones

    SciTech Connect

    Yeunghaw Ho; Squires, R.R. )

    1992-12-30

    A common feature of classical, intuitive models and modern molecular orbital-based theories for diastereoselectivity in ketone reduction reactions is an emphasis on the structural and electronic properties of the substrate, despite the fact that the stereochemical outcome of these reactions often displays marked sensitivity to the solvent and the type of counter-ion employed with ionic and polar reducing agents. One way to separate intrinsic and extrinsic effects on the stereochemistry of ketone reduction reactions is to examine them in the gas phase, where solvent and counterion effects are absent. The authors describe here an experimental method for distinguishing the diastereomeric products of gas-phase hydride reduction reactions, and its application in determining the intrinsic diastereoselectivity involved in reductions of alkyl-substituted cyclohexanones. 1 tab.

  20. Slow Conductances Could Underlie Intrinsic Phase-Maintaining Properties of Isolated Lobster (Panulirus interruptus) Pyloric Neurons

    PubMed Central

    Hooper, Scott L.; Buchman, Einat; Weaver, Adam L.; Thuma, Jeffrey B.; Hobbs, Kevin H.

    2009-01-01

    The rhythmic pyloric network of the lobster stomatogastric system approximately maintains phase (that is, the burst durations and durations between the bursts of its neurons change proportionally) when network cycle period is altered by current injection into the network pacemaker (Hooper, 1997a,b). When isolated from the network and driven by rhythmic hyperpolarizing current pulses, the delay to firing after each pulse of at least one network neuron type (Pyloric, PY) varies in a phase-maintaining manner when cycle period is varied (Hooper, 1998). These variations require PY neurons to have intrinsic mechanisms that respond to changes in neuron activity on time scales at least as long as two seconds. Slowly activating and deactivating conductances could provide such a mechanism. We tested this possibility by building models containing various slow conductances. This work showed that such conductances could indeed support intrinsic phase-maintenance and we show here results for one such conductance, a slow potassium conductance. These conductances supported phase maintenance because their mean activation level changed, hence altering neuron post-inhibition firing delay, when the rhythmic input to the neuron changed. Switching the sign of the dependence of slow conductance activation and deactivation on membrane potential resulted in neuron delays switching to change in an anti-phase maintaining manner. These data suggest that slow conductances or similar slow processes such as changes in intracellular Ca2+ concentration could underlie phase maintenance in pyloric network neurons. PMID:19211890

  1. Uncovering the intrinsic size dependence of hydriding phase transformations in nanocrystals

    NASA Astrophysics Data System (ADS)

    Bardhan, Rizia; Hedges, Lester O.; Pint, Cary L.; Javey, Ali; Whitelam, Stephen; Urban, Jeffrey J.

    2013-10-01

    A quantitative understanding of nanocrystal phase transformations would enable more efficient energy conversion and catalysis, but has been hindered by difficulties in directly monitoring well-characterized nanoscale systems in reactive environments. We present a new in situ luminescence-based probe enabling direct quantification of nanocrystal phase transformations, applied here to the hydriding transformation of palladium nanocrystals. Our approach reveals the intrinsic kinetics and thermodynamics of nanocrystal phase transformations, eliminating complications of substrate strain, ligand effects and external signal transducers. Clear size-dependent trends emerge in nanocrystals long accepted to be bulk-like in behaviour. Statistical mechanical simulations show these trends to be a consequence of nanoconfinement of a thermally driven, first-order phase transition: near the phase boundary, critical nuclei of the new phase are comparable in size to the nanocrystal itself. Transformation rates are then unavoidably governed by nanocrystal dimensions. Our results provide a general framework for understanding how nanoconfinement fundamentally impacts broad classes of thermally driven solid-state phase transformations relevant to hydrogen storage, catalysis, batteries and fuel cells.

  2. An effect of temperature distribution on terahertz phase dynamics in intrinsic Josephson junctions

    NASA Astrophysics Data System (ADS)

    Asai, Hidehiro; Kawabata, Shiro

    2013-11-01

    In this study, we numerically calculate the temperature distribution and the THz phase dynamics in the mesa-structured intrinsic Josephson junctions (IJJs) using the thermal diffusion equation and the Sine-Gordon equation. We observe that the temperature distribution has a broad peak around the center region of the IJJ mesa. Under a high external current, a “hot spot” where the temperature is locally higher than the superconducting critical temperature appears around this region. The transverse Josephson plasma wave is strongly excited by the inhomogeneous temperature distribution in the mesa. This gives rise to intense THz emission.

  3. Association of intrinsic circadian period with morningness-eveningness, usual wake time, and circadian phase

    NASA Technical Reports Server (NTRS)

    Duffy, J. F.; Rimmer, D. W.; Czeisler, C. A.

    2001-01-01

    The biological basis of preferences for morning or evening activity patterns ("early birds" and "night owls") has been hypothesized but has remained elusive. The authors reported that, compared with evening types, the circadian pacemaker of morning types was entrained to an earlier hour with respect to both clock time and wake time. The present study explores a chronobiological mechanism by which the biological clock of morning types may be set to an earlier hour. Intrinsic period, a fundamental property of the circadian system, was measured in a month-long inpatient study. A subset of participants also had their circadian phase assessed. Participants completed a morningness-eveningness questionnaire before study. Circadian period was correlated with morningness-eveningness, circadian phase, and wake time, demonstrating that a fundamental property of the circadian pacemaker is correlated with the behavioral trait of morningness-eveningness.

  4. Extrinsic and Intrinsic Responses to Environmental Change: Insights from Terrestrial Paleoecological Archives

    NASA Astrophysics Data System (ADS)

    Seddon, A. W. R.; Mackay, A. W.

    2015-12-01

    Current understanding of ecological behaviour indicates that systems can experience sudden and abrupt changes in state, driven either by a large external change in environmental conditions (extrinsically forced), or the result of a set local feedbacks and site-specific interactions (intrinsically mediated responses). Responses mediated by intrinsic processes are notoriously diffi- cult to predict, they can occur as slow environmental variables gradually erode the resilience of the system eventually resulting in threshold transitions between alternative stable states. Finding ways to identify, model and predict such complex ecosystem behavior has been identified as a priority research challenge for both ecology and paleoecology. The paleoecological record can play a role in understanding the processes behind abrupt ecological change because it enables the reconstruction of processes occurring over decadal-centennial timescales or longer. Therefore, paleoecological data can be used to identify the existence of ecological thresholds and to investigate the environmental processes that can lead to loss of resilience and abrupt transitions between alternate states. In addition, incidences of abrupt vegetation changes in the past can serve as palaeoecological model systems; analogues of abrupt dynamics which can be used to test theories surrounding ecological responses to climate change. Here, I present examples from a range of terrestrial ecosystems (Holocene environmental changes from a coastal lagoon in the Galapagos Islands; Northern European vegetation changes since the last deglaciation; the North American hemlock decline) demonstrating evidence of abrupt ecosystem change. For each system I present a set of statistical techniques tailored to distin- guish between extrinsic versus intrinsically mediated ecological responses. Examples are provided from both single sites (i.e. landscape scale) and multiple sites (regional-continental scale). These techniques provide a

  5. Terahertz Responses of Intrinsic Josephson Junctions in High T{sub C} Superconductors

    SciTech Connect

    Wang, H. B.; Wu, P. H.; Yamashita, T.

    2001-09-03

    High frequency responses of intrinsic Josephson junctions up to 2.5THz, including the observation of Shapiro steps under various conditions, are reported and discussed in this Letter. The sample was an array of intrinsic Josephson junctions singled out from inside a high T{sub C} superconducting Bi{sub 2}Sr {sub 2}CaCu{sub 2}O{sub 8+x} single crystal, with a bow-tie antenna integrated to it. The number of junctions in the array was controllable, the junctions were homogeneous, the distribution of applied irradiation among the junctions was even, and the junctions could synchronously respond to high frequency irradiation.

  6. Complete Firing-Rate Response of Neurons with Complex Intrinsic Dynamics.

    PubMed

    Puelma Touzel, Maximilian; Wolf, Fred

    2015-12-01

    The response of a neuronal population over a space of inputs depends on the intrinsic properties of its constituent neurons. Two main modes of single neuron dynamics-integration and resonance-have been distinguished. While resonator cell types exist in a variety of brain areas, few models incorporate this feature and fewer have investigated its effects. To understand better how a resonator's frequency preference emerges from its intrinsic dynamics and contributes to its local area's population firing rate dynamics, we analyze the dynamic gain of an analytically solvable two-degree of freedom neuron model. In the Fokker-Planck approach, the dynamic gain is intractable. The alternative Gauss-Rice approach lifts the resetting of the voltage after a spike. This allows us to derive a complete expression for the dynamic gain of a resonator neuron model in terms of a cascade of filters on the input. We find six distinct response types and use them to fully characterize the routes to resonance across all values of the relevant timescales. We find that resonance arises primarily due to slow adaptation with an intrinsic frequency acting to sharpen and adjust the location of the resonant peak. We determine the parameter regions for the existence of an intrinsic frequency and for subthreshold and spiking resonance, finding all possible intersections of the three. The expressions and analysis presented here provide an account of how intrinsic neuron dynamics shape dynamic population response properties and can facilitate the construction of an exact theory of correlations and stability of population activity in networks containing populations of resonator neurons. PMID:26720924

  7. Complete Firing-Rate Response of Neurons with Complex Intrinsic Dynamics

    PubMed Central

    Puelma Touzel, Maximilian; Wolf, Fred

    2015-01-01

    The response of a neuronal population over a space of inputs depends on the intrinsic properties of its constituent neurons. Two main modes of single neuron dynamics–integration and resonance–have been distinguished. While resonator cell types exist in a variety of brain areas, few models incorporate this feature and fewer have investigated its effects. To understand better how a resonator’s frequency preference emerges from its intrinsic dynamics and contributes to its local area’s population firing rate dynamics, we analyze the dynamic gain of an analytically solvable two-degree of freedom neuron model. In the Fokker-Planck approach, the dynamic gain is intractable. The alternative Gauss-Rice approach lifts the resetting of the voltage after a spike. This allows us to derive a complete expression for the dynamic gain of a resonator neuron model in terms of a cascade of filters on the input. We find six distinct response types and use them to fully characterize the routes to resonance across all values of the relevant timescales. We find that resonance arises primarily due to slow adaptation with an intrinsic frequency acting to sharpen and adjust the location of the resonant peak. We determine the parameter regions for the existence of an intrinsic frequency and for subthreshold and spiking resonance, finding all possible intersections of the three. The expressions and analysis presented here provide an account of how intrinsic neuron dynamics shape dynamic population response properties and can facilitate the construction of an exact theory of correlations and stability of population activity in networks containing populations of resonator neurons. PMID:26720924

  8. Characterizing and modeling the intrinsic light response of rat ganglion-cell photoreceptors.

    PubMed

    Walch, Olivia J; Zhang, L Samantha; Reifler, Aaron N; Dolikian, Michael E; Forger, Daniel B; Wong, Kwoon Y

    2015-11-01

    Intrinsically photosensitive retinal ganglion cells (ipRGCs) mediate both image-forming vision and non-image-forming visual responses such as pupillary constriction and circadian photoentrainment. Five types of ipRGCs, named M1-M5, have been discovered in rodents. To further investigate their photoresponse properties, we made multielectrode array spike recordings from rat ipRGCs, classified them into M1, M2/M4, and M3/M5 clusters, and measured their intrinsic, melanopsin-based responses to single and flickering light pulses. Results showed that ipRGC spiking can track flickers up to ∼0.2 Hz in frequency and that flicker intervals between 5 and 14 s evoke the most spikes. We also learned that melanopsin's integration time is intensity and cluster dependent. Using these data, we constructed a mathematical model for each cluster's intrinsic photoresponse. We found that the data for the M1 cluster are best fit by a model that assumes a large photoresponse, causing the cell to enter depolarization block. Our models also led us to hypothesize that the M2/M4 and M3/M5 clusters experience comparable photoexcitation but that the M3/M5 cascade decays significantly faster than the M2/M4 cascade, resulting in different response waveforms between these clusters. These mathematical models will help predict how each ipRGC cluster might respond to stimuli of any waveform and could inform the invention of lighting technologies that promote health through melanopsin stimulation.

  9. Intrinsic slow charge response in the perovskite solar cells: Electron and ion transport

    SciTech Connect

    Shi, Jiangjian; Xu, Xin; Zhang, Huiyin; Luo, Yanhong; Li, Dongmei; Meng, Qingbo

    2015-10-19

    The intrinsic charge response and hysteresis characteristic in the perovskite solar cell has been investigated by an electrically modulated transient photocurrent technology. An ultraslow charge response process in the timescale of seconds is observed, which can be well explained by the ion migration in the perovskite CH{sub 3}NH{sub 3}PbI{sub 3} film driven by multiple electric fields derived from the heterojunction depletion charge, the external modulation, and the accumulated ion charge. Furthermore, theoretical calculation of charge transport reveals that the hysteresis behavior is also significantly influenced by the interfacial charge extraction velocity and the carrier transport properties inside the cell.

  10. Interdiffusion and intrinsic diffusion in the NiAl /delta/ phase of the Al-Ni system

    NASA Technical Reports Server (NTRS)

    Shankar, S.; Seigle, L. L.

    1978-01-01

    Interdiffusion coefficients at 950 to 1150 C and the ratio of intrinsic diffusion coefficients at 1100 C were measured as functions of composition in the NiAl (delta) phase of the Al-Ni system, using a vapor-solid technique. Diffusivity values were also obtained for the Ni3Al (epsilon) and Ni (Al) solid solution (zeta) phases from 950 to 1150 C. The interdiffusion coefficient in NiAl (delta) varies several orders of magnitude over the delta phase field with a deep minimum in the diffusivity-composition curve at 48 to 49 at% Al. The ratio of intrinsic diffusion coefficients DNi/DAl, in the delta phase also varies with composition from a value of 3 to 3.5 below 50 at% Al to 0.1 or less above 50 at% Al.

  11. Caulobacter crescentus intrinsic dimorphism provides a prompt bimodal response to copper stress.

    PubMed

    Lawarée, Emeline; Gillet, Sébastien; Louis, Gwennaëlle; Tilquin, Françoise; Le Blastier, Sophie; Cambier, Pierre; Matroule, Jean-Yves

    2016-01-01

    Stress response to fluctuating environments often implies a time-consuming reprogramming of gene expression. In bacteria, the so-called bet hedging strategy, which promotes phenotypic stochasticity within a cell population, is the only fast stress response described so far(1). Here, we show that Caulobacter crescentus asymmetrical cell division allows an immediate bimodal response to a toxic metals-rich environment by allocating specific defence strategies to morphologically and functionally distinct siblings. In this context, a motile swarmer cell favours negative chemotaxis to flee from a copper source, whereas a sessile stalked sibling engages a ready-to-use PcoAB copper homeostasis system, providing evidence of a prompt stress response through intrinsic bacterial dimorphism. PMID:27562256

  12. Striatal intrinsic reinforcement signals during recognition memory: relationship to response bias and dysregulation in schizophrenia.

    PubMed

    Wolf, Daniel H; Gerraty, Raphaelt; Satterthwaite, Theodore D; Loughead, James; Campellone, Timothy; Elliott, Mark A; Turetsky, Bruce I; Gur, Ruben C; Gur, Raquel E

    2011-01-01

    Ventral striatum (VS) is a critical brain region for reinforcement learning and motivation, and VS hypofunction is implicated in psychiatric disorders including schizophrenia. Providing rewards or performance feedback has been shown to activate VS. Intrinsically motivated subjects performing challenging cognitive tasks are likely to engage reinforcement circuitry even in the absence of external feedback or incentives. However, such intrinsic reinforcement responses have received little attention, have not been examined in relation to behavioral performance, and have not been evaluated for impairment in neuropsychiatric disorders such as schizophrenia. Here we used fMRI to examine a challenging "old" vs. "new" visual recognition task in healthy subjects and patients with schizophrenia. Targets were unique fractal stimuli previously presented as salient distractors in a visual oddball task, producing incidental memory encoding. Based on the prediction error theory of reinforcement learning, we hypothesized that correct target recognition would activate VS in controls, and that this activation would be greater in subjects with lower expectation of responding correctly as indexed by a more conservative response bias. We also predicted these effects would be reduced in patients with schizophrenia. Consistent with these predictions, controls activated VS and other reinforcement processing regions during correct recognition, with greater VS activation in those with a more conservative response bias. Patients did not show either effect, with significant group differences suggesting hyporesponsivity in patients to internally generated feedback. These findings highlight the importance of accounting for intrinsic motivation and reward when studying cognitive tasks, and add to growing evidence of reward circuit dysfunction in schizophrenia that may impact cognition and function.

  13. Simultaneous imaging of intrinsic optical signals and cerebral vessel responses during cortical spreading depression in rats

    NASA Astrophysics Data System (ADS)

    Li, Pengcheng; Chen, Shangbin; Luo, Weihua; Luo, Qingming

    2003-12-01

    Cortical spreading depression (CSD) is an important disease model for migraine and cerebral ischemia. We investigated the spatio-temporal characteristics of the intrinsic optical signals (IOS) at 570 nm and the cerebral blood vessel responses during CSD simultaneously by optical reflectance imaging in vivo. The CSD were induced by pinprick in 10 α-chloralose/urethane anesthetized Sprague-Dawley rats. A four-phasic IOS response was observed at pial arteries and parenchymal sites in all experimental animals and an initial slight pial arteries dilation (21.5%+/-13.6%) and constriction (-4.2%+/-3.5%) precedes the dramatic dilation (69.2%+/-26.1%) of pial arterioles was recorded. Our experimental results show a high correlation (r = 0.89+/-0.025) between the IOS response and the diameter changes of the cerebral blood vessels during CSD in rats.

  14. Translating innate response into long-lasting antibody response by the intrinsic antigen-adjuvant properties of papaya mosaic virus

    PubMed Central

    Acosta-Ramírez, Elizabeth; Pérez-Flores, Rebeca; Majeau, Nathalie; Pastelin-Palacios, Rodolfo; Gil-Cruz, Cristina; Ramírez-Saldaña, Maricela; Manjarrez-Orduño, Nataly; Cervantes-Barragán, Luisa; Santos-Argumedo, Leopoldo; Flores-Romo, Leopoldo; Becker, Ingeborg; Isibasi, Armando; Leclerc, Denis; López-Macías, Constantino

    2008-01-01

    Identifying the properties of a molecule involved in the efficient activation of the innate and adaptive immune responses that lead to long-lasting immunity is crucial for vaccine and adjuvant development. Here we show that the papaya mosaic virus (PapMV) is recognized by the immune system as a pathogen-associated molecular pattern (PAMP) and as an antigen in mice (Pamptigen). A single immunization of PapMV without added adjuvant efficiently induced both cellular and specific long-lasting antibody responses. PapMV also efficiently activated innate immune responses, as shown by the induction of lipid raft aggregation, secretion of pro-inflammatory cytokines, up-regulation of co-stimulatory molecules on dendritic cells and macrophages, and long-lasting adjuvant effects upon the specific antibody responses to model antigens. PapMV mixed with Salmonella enterica serovar Typhi (S. typhi) outer membrane protein C increased its protective capacity against challenge with S. typhi, revealing the intrinsic adjuvant properties of PapMV in the induction of immunity. Antigen-presenting cells loaded with PapMV efficiently induced antibody responses in vivo, which may link the innate and adaptive responses observed. PapMV recognition as a Pamptigen might be translated into long-lasting antibody responses and protection observed. These properties could be used in the development of new vaccine platforms. PMID:18070030

  15. Measuring Students' Perceptions of Personal and Social Responsibility and the Relationship to Intrinsic Motivation in Urban Physical Education

    ERIC Educational Resources Information Center

    Li, Weidong; Wright, Paul M.; Rukavina, Paul Bernard; Pickering, Molly

    2008-01-01

    The purpose of the current study was to test the validity and reliability of a two-factor model of the Personal and Social Responsibility Questionnaire (PSRQ) and examine the relationships between perceptions of personal and social responsibility and intrinsic motivation in physical education. Participants were 253 middle school students who…

  16. Berry phases and the intrinsic thermal Hall effect in high-temperature cuprate superconductors.

    PubMed

    Cvetkovic, Vladimir; Vafek, Oskar

    2015-01-01

    Bogolyubov quasiparticles move in a practically uniform magnetic field in the vortex state of high-temperature cuprate superconductors. When set in motion by an externally applied heat current, the quasiparticles' trajectories may bend, causing a temperature gradient perpendicular to the heat current and the applied magnetic field, resulting in the thermal Hall effect. Here we relate this effect to the Berry curvature of quasiparticle magnetic sub-bands, and calculate the dependence of the intrinsic thermal Hall conductivity on superconductor's temperature, magnetic field and the amplitude of the d-wave pairing. The intrinsic contribution to thermal Hall conductivity displays a rapid onset with increasing temperature, which compares favourably with existing experiments at high magnetic field on the highest purity samples. Because such temperature onset is related to the pairing amplitude, our finding may help to settle a much-debated question of the bulk value of the pairing strength in cuprate superconductors in magnetic field. PMID:25758469

  17. Inferring cardiac phase response curve in vivo

    NASA Astrophysics Data System (ADS)

    Pikovsky, Arkady; Kralemann, Bjoern; Fruehwirth, Matthias; Rosenblum, Michael; Kenner, Thomas; Schaefer, Jochen; Moser, Maximilian

    2014-03-01

    Characterizing properties of biological oscillators with phase response cirves (PRC) is one of main theoretical tools in neuroscience, cardio-respiratory physiology, and chronobiology. We present a technique that allows the extraction of the PRC from a non-invasive observation of a system consisting of two interacting oscillators, in this case heartbeat and respiration, in its natural environment and under free-running conditions. We use this method to obtain the phase coupling functions describing cardio-respiratory interactions and the phase response curve of 17 healthy humans. We show at which phase the cardiac beat is susceptible to respiratory drive and extract the respiratory-related component of heart rate variability. This non-invasive method of bivariate data analysis for the determination of phase response curves of coupled oscillators may find application in other biological and physical systems.

  18. Macroscopic quantum tunneling and phase diffusion in a La2-xSrxCuO4 intrinsic Josephson junction stack

    NASA Astrophysics Data System (ADS)

    Kubo, Yuimaru; Sboychakov, A. O.; Nori, Franco; Takahide, Y.; Ueda, S.; Tanaka, I.; Islam, A. T. M. N.; Takano, Y.

    2012-10-01

    We performed measurements of switching current distribution in a submicrometer La2-xSrxCuO4 (LSCO) intrinsic Josephson junction (IJJ) stack in a wide temperature range. The escape rate saturates below approximately 2 K, indicating that the escape event is dominated by a macroscopic quantum tunneling (MQT) process with a crossover temperature T*≈2K. We applied the theory of MQT for IJJ stacks, taking into account dissipation and the phase retrapping effect in the LSCO IJJ stack. The theory is in good agreement with the experiment both in the MQT and in the thermal activation regimes.

  19. Phase-response curves of coupled oscillators.

    PubMed

    Ko, Tae-Wook; Ermentrout, G Bard

    2009-01-01

    Many real oscillators are coupled to other oscillators, and the coupling can affect the response of the oscillators to stimuli. We investigate phase-response curves (PRCs) of coupled oscillators. The PRCs for two weakly coupled phase-locked oscillators are analytically obtained in terms of the PRC for uncoupled oscillators and the coupling function of the system. Through simulation and analytic methods, the PRCs for globally coupled oscillators are also discussed.

  20. Laser Chemosensor with Rapid Responsivity and Inherent Memory Based on a Polymer of Intrinsic Microporosity

    PubMed Central

    Wang, Yue; McKeown, Neil B.; Msayib, Kadhum J.; Turnbull, Graham A.; Samuel, Ifor D. W.

    2011-01-01

    This work explores the use of a polymer of intrinsic microporosity (PIM-1) as the active layer within a laser sensor to detect nitroaromatic-based explosive vapors. We show successful detection of dinitrobenzene (DNB) by monitoring the real-time photoluminescence. We also show that PIM-1 has an inherent memory, so that it accumulates the analyte during exposure. In addition, the optical gain and refractive index of the polymer were studied by amplified spontaneous emission and variable-angle ellipsometry, respectively. A second-order distributed feedback PIM-1 laser sensor was fabricated and found to show an increase in laser threshold of 2.5 times and a reduction of the laser slope efficiency by 4.4 times after a 5-min exposure to the DNB vapor. For pumping at 2 times threshold, the lasing action was stopped within 30 s indicating that PIM-1 has a very fast responsivity and as such has a potential sensing ability for ultra-low-concentration explosives. PMID:22163750

  1. Identification of intrinsic deep level defects responsible for electret behavior in TlGaSe2 layered semiconductor

    NASA Astrophysics Data System (ADS)

    Seyidov, MirHasan Yu.; Mikailzade, Faik A.; Uzun, Talip; Odrinsky, Andrei P.; Yakar, Emin; Aliyeva, Vafa B.; Babayev, Sardar S.; Mammadov, Tofig G.

    2016-02-01

    Unusual behavior of pyroelectric current signal polarity near the Curie point (Tc) was observed for TlGaSe2 a ferroelectric-semiconductor. It has been revealed that the polarity of the spontaneous polarization near Tc depends on the sample poling prehistory. In particular, applying an external electric field only in the temperature range of the paraelectric state during cooling regime in darkness brought to the depolarization current at Tc with the sign opposite to the external field polarity. Otherwise, if the sample was poled in the temperature interval of the incommensurate phase, pyroelectric current exhibits a peak at Tc with the polarity that is the same as for the external poling electric field. These observations indicate that internal electric field is present in the bulk and near-surface layer regions of the electrically poled single crystal TlGaSe2. Possible mechanisms and origins responsible for the internal electric fields in TlGaSe2 are discussed. It is shown that the formation of internal electric fields in TlGaSe2 is due to charging of intrinsic native defects during the poling process. Characteristics of electrically active intrinsic defects in TlGaSe2 were investigated by using of Photo-Induced Current Transient Spectroscopy (PICTS) technique. Six deep defect levels in the band gap of TlGaSe2 were determined, which were localized both in the bulk and on the surface of the sample and could be electrically charged. The correlation between polarization effects and PICTS results has been established. It was shown that native deep defects (A3-A6) localized in the bulk of crystal are responsible for hetero-charge formation and negative sign of the pyroelectric current peak observed around the Curie temperature after poling the sample in the temperature intervals well above Tc. It was also shown that the positive sign pyrocurrent observed near the Curie point is attributed to the homo-charge formed by native A2-trapping centers which are localized near

  2. Microsecond Molecular Dynamics Simulations of Intrinsically Disordered Proteins Involved in the Oxidative Stress Response

    PubMed Central

    Cino, Elio A.; Wong-ekkabut, Jirasak; Karttunen, Mikko; Choy, Wing-Yiu

    2011-01-01

    Intrinsically disordered proteins (IDPs) are abundant in cells and have central roles in protein-protein interaction networks. Interactions between the IDP Prothymosin alpha (ProTα) and the Neh2 domain of Nuclear factor erythroid 2-related factor 2 (Nrf2), with a common binding partner, Kelch-like ECH-associated protein 1(Keap1), are essential for regulating cellular response to oxidative stress. Misregulation of this pathway can lead to neurodegenerative diseases, premature aging and cancer. In order to understand the mechanisms these two disordered proteins employ to bind to Keap1, we performed extensive 0.5–1.0 microsecond atomistic molecular dynamics (MD) simulations and isothermal titration calorimetry experiments to investigate the structure/dynamics of free-state ProTα and Neh2 and their thermodynamics of bindings. The results show that in their free states, both ProTα and Neh2 have propensities to form bound-state-like β-turn structures but to different extents. We also found that, for both proteins, residues outside the Keap1-binding motifs may play important roles in stabilizing the bound-state-like structures. Based on our findings, we propose that the binding of disordered ProTα and Neh2 to Keap1 occurs synergistically via preformed structural elements (PSEs) and coupled folding and binding, with a heavy bias towards PSEs, particularly for Neh2. Our results provide insights into the molecular mechanisms Neh2 and ProTα bind to Keap1, information that is useful for developing therapeutics to enhance the oxidative stress response. PMID:22125611

  3. Intrinsic disorder as a generalizable strategy for the rational design of highly responsive, allosterically cooperative receptors

    PubMed Central

    Simon, Anna J.; Vallée-Bélisle, Alexis; Ricci, Francesco; Plaxco, Kevin W.

    2014-01-01

    Control over the sensitivity with which biomolecular receptors respond to small changes in the concentration of their target ligand is critical for the proper function of many cellular processes. Such control could likewise be of utility in artificial biotechnologies, such as biosensors, genetic logic gates, and “smart” materials, in which highly responsive behavior is of value. In nature, the control of molecular responsiveness is often achieved using “Hill-type” cooperativity, a mechanism in which sequential binding events on a multivalent receptor are coupled such that the first enhances the affinity of the next, producing a steep, higher-order dependence on target concentration. Here, we use an intrinsic-disorder–based mechanism that can be implemented without requiring detailed structural knowledge to rationally introduce this potentially useful property into several normally noncooperative biomolecules. To do so, we fabricate a tandem repeat of the receptor that is destabilized (unfolded) via the introduction of a long, unstructured loop. The first binding event requires the energetically unfavorable closing of this loop, reducing its affinity relative to that of the second binding event, which, in contrast occurs at a preformed site. Using this approach, we have rationally introduced cooperativity into three unrelated DNA aptamers, achieving in the best of these a Hill coefficient experimentally indistinguishable from the theoretically expected maximum. The extent of cooperativity and thus the steepness of the binding transition are, moreover, well modeled as simple functions of the energetic cost of binding-induced folding, speaking to the quantitative nature of this design strategy. PMID:25288724

  4. In-phase electrodynamics and terahertz wave emission in extended intrinsic Josephson junctions

    NASA Astrophysics Data System (ADS)

    Koyama, Tomio; Matsumoto, Hideki; Machida, Masahiko; Kadowaki, Kazuo

    2009-03-01

    Strong emission of subterahertz electromagnetic (EM) waves has been observed recently in the high Tc superconductor Bi2Sr2CaCu2O8 intrinsic Josephson junctions (IJJ’s). We investigate numerically the dynamics of the EM fields both inside and outside the IJJ’s emitting terahertz EM waves under a constant bias current, using two-dimensional models composed of IJJ’s and the space surrounding them: (1) xy model and (2) xz model. In the xy model we investigate the EM modes excited in the rectangular junctions. In the voltage state the Josephson oscillation generates the oscillating EM field having nodes inside the junctions. The number of nodes depends on the DC voltage appearing in the junctions, and their direction is parallel to the shorter side of the junctions. The EM field shows a complex distribution pattern in the near field region. In the region far from the junctions we have only the expanding EM wave oscillating with the Josephson frequency. In the xz model we study the EM waves emitted in the xz plane from the junctions covered with normal electrodes. It is shown that the power of the emitted EM waves has distribution similar to that in the dipole emission in the system where electrodes of the same size are attached on top and bottom junctions. In the asymmetric system where the lower electrode is larger than the upper one the power distribution of emitted EM wave deviates from that in the dipole emission.

  5. Intrinsic increase in lymphangion muscle contractility in response to elevated afterload

    PubMed Central

    Scallan, Joshua P.; Wolpers, John H.; Muthuchamy, Mariappan; Gashev, Anatoliy A.; Zawieja, David C.

    2012-01-01

    Collecting lymphatic vessels share functional and biochemical characteristics with cardiac muscle; thus, we hypothesized that the lymphatic vessel pump would exhibit behavior analogous to homeometric regulation of the cardiac pump in its adaptation to elevated afterload, i.e., an increase in contractility. Single lymphangions containing two valves were isolated from the rat mesenteric microcirculation, cannulated, and pressurized for in vitro study. Pressures at either end of the lymphangion [input pressure (Pin), preload; output pressure (Pout), afterload] were set by a servo controller. Intralymphangion pressure (PL) was measured using a servo-null micropipette while internal diameter and valve positions were monitored using video methods. The responses to step- and ramp-wise increases in Pout (at low, constant Pin) were determined. PL and diameter data recorded during single contraction cycles were used to generate pressure-volume (P-V) relationships for the subsequent analysis of lymphangion pump behavior. Ramp-wise Pout elevation led to progressive vessel constriction, a rise in end-systolic diameter, and an increase in contraction frequency. Step-wise Pout elevation produced initial vessel distention followed by time-dependent declines in end-systolic and end-diastolic diameters. Significantly, a 30% leftward shift in the end-systolic P-V relationship accompanied an 84% increase in dP/dt after a step increase in Pout, consistent with an increase in contractility. Calculations of stroke work from the P-V loop area revealed that robust pumps produced net positive work to expel fluid throughout the entire afterload range, whereas weaker pumps exhibited progressively more negative work as gradual afterload elevation led to pump failure. We conclude that lymphatic muscle adapts to output pressure elevation with an intrinsic increase in contractility and that this compensatory mechanism facilitates the maintenance of lymph pump output in the face of edemagenic and

  6. Intrinsic Charge Transport across Phase Transitions in Hybrid Organo-Inorganic Perovskites.

    PubMed

    Yi, Hee Taek; Wu, Xiaoxi; Zhu, Xiaoyang; Podzorov, Vitaly

    2016-08-01

    Hall effect measurements in CH3 NH3 PbBr3 single crystals reveal that the charge-carrier mobility follows an inverse-temperature power-law dependence, μ ∝ T(-) (γ) , with the power exponent γ = 1.4 ± 0.1 in the cubic phase, indicating an acoustic-phonon-dominated carrier scattering, and γ = 0.5 ± 0.1 in the tetragonal phase, suggesting another dominant mechanism, such as a piezoelectric or space-charge scattering. PMID:27185304

  7. Interdiffusion in the Mg-Al system and Intrinsic Diffusion in (Al3Mg2) Phase

    SciTech Connect

    Brennan, Sarah; Bermudez, Katrina; Kulkarni, Nagraj S; Sohn, Yong Ho

    2011-01-01

    Increasing use and development of lightweight Mg-alloys have led to the desire for more fundamental research in and understanding of Mg-based systems. As a strengthening component, Al is one of the most important and common alloying elements for Mg-alloys. In this study, solid-to-solid diffusion couple techniques were employed to examine the interdiffusion between pure Mg and Al. Diffusion anneals were carried out at 300 , 350 , and 400 C for 720, 360, and 240 hours, respectively. Optical and scanning electron microscopies (SEM) were employed to observe the formation of the intermetallics -Al12Mg17 and -Al3Mg2, but not -phase. Concentration profiles were determined using X-ray energy dispersive spectroscopy (XEDS). The growth constants and activation energies were determined for each intermetallic phase.

  8. Heterodyne coherent anti-Stokes Raman scattering by the phase control of its intrinsic background

    SciTech Connect

    Wang Xi; Wang Kai; Welch, George R.; Sokolov, Alexei V.

    2011-08-15

    We demonstrate the use of femtosecond laser pulse shaping for precise control of the interference between the coherent anti-Stokes Raman scattering (CARS) signal and the coherent nonresonant background generated within the same sample volume. Our technique is similar to heterodyne detection with the coherent background playing the role of the local oscillator field. In our experiment, we first apply two ultrashort (near-transform-limited) femtosecond pump and Stokes laser pulses to excite coherent molecular oscillations within a sample. After a short and controllable delay, we then apply a laser pulse that scatters off of these oscillations to produce the CARS signal. By making fine adjustments to the probe field spectral profile, we vary the relative phase between the Raman-resonant signal and the nonresonant background, and we observe a varying spectral interference pattern. These controlled variations of the measured pattern reveal the phase information within the Raman spectrum.

  9. Intrinsic magnetic properties of single-phase Mn1+xGa (0 < x < 1) alloys

    PubMed Central

    Lu, Q. M.; Yue, M.; Zhang, H. G.; Wang, M. L.; Yu, F.; Huang, Q. Z.; Ryan, D. H.; Altounian, Z.

    2015-01-01

    Magnetization measurements have been carried out on a series of carefully prepared single-phase Mn1 + xGa (0 < x < 1) alloys. The saturation magnetization Ms, measured at 5 K, has a value of 92.0 emu/g for x = 0.15. This is the highest value reported in these alloys and is close to the calculated value of 116 emu/g for the stoichiometric compound (x = 0). Ms decreases gradually with x and has a value of 60.7 emu/g for x = 0.86. This behavior is consistent with the extra Mn atoms occupying Ga sites and coupling antiferromagnetically with the rest of the Mn atoms. The intrinsic magnetic properties of the Mn-Ga alloys indicate their great potential as novel, rare-earth free permanent magnetic materials. PMID:26597458

  10. Intrinsic optical signal imaging of glucose-stimulated physiological responses in the insulin secreting INS-1 β-cell line

    NASA Astrophysics Data System (ADS)

    Li, Yi-Chao; Cui, Wan-Xing; Wang, Xu-Jing; Amthor, Franklin; Yao, Xin-Cheng

    2011-03-01

    Intrinsic optical signal (IOS) imaging has been established for noninvasive monitoring of stimulus-evoked physiological responses in the retina and other neural tissues. Recently, we extended the IOS imaging technology for functional evaluation of insulin secreting INS-1 cells. INS-1 cells provide a popular model for investigating β-cell dysfunction and diabetes. Our experiments indicate that IOS imaging allows simultaneous monitoring of glucose-stimulated physiological responses in multiple cells with high spatial (sub-cellular) and temporal (sub-second) resolution. Rapid image sequences reveal transient optical responses that have time courses comparable to glucose-evoked β-cell electrical activities.

  11. Voltage sensing systems and methods for passive compensation of temperature related intrinsic phase shift

    DOEpatents

    Davidson, James R.; Lassahn, Gordon D.

    2001-01-01

    A small sized electro-optic voltage sensor capable of accurate measurement of high levels of voltages without contact with a conductor or voltage source is provided. When placed in the presence of an electric field, the sensor receives an input beam of electromagnetic radiation into the sensor. A polarization beam displacer serves as a filter to separate the input beam into two beams with orthogonal linear polarizations. The beam displacer is oriented in such a way as to rotate the linearly polarized beams such that they enter a Pockels crystal at a preferred angle of 45 degrees. The beam displacer is therefore capable of causing a linearly polarized beam to impinge a crystal at a desired angle independent of temperature. The Pockels electro-optic effect induces a differential phase shift on the major and minor axes of the input beam as it travels through the Pockels crystal, which causes the input beam to be elliptically polarized. A reflecting prism redirects the beam back through the crystal and the beam displacer. On the return path, the polarization beam displacer separates the elliptically polarized beam into two output beams of orthogonal linear polarization representing the major and minor axes. In crystals that introduce a phase differential attributable to temperature, a compensating crystal is provided to cancel the effect of temperature on the phase differential of the input beam. The system may include a detector for converting the output beams into electrical signals, and a signal processor for determining the voltage based on an analysis of the output beams. The output beams are amplitude modulated by the frequency of the electric field and the amplitude of the output beams is proportional to the magnitude of the electric field, which is related to the voltage being measured.

  12. The Pervasive Negative Effects of Rewards on Intrinsic Motivation: Response to Cameron (2001).

    ERIC Educational Resources Information Center

    Deci, Edward L.; Ryan, Richard M.; Koestner, Richard

    2001-01-01

    Replies to commentary by J. Cameron asserting that the negative results of extrinsic reward on intrinsic motivation are limited and avoidable. Suggests that the most recent meta analysis by Cameron and others shares methodological weaknesses with an earlier analysis, lacking ecological validity. (SLD)

  13. Maggot excretion products from the blowfly Lucilia sericata contain contact phase/intrinsic pathway-like proteases with procoagulant functions.

    PubMed

    Kahl, M; Gökçen, A; Fischer, S; Bäumer, M; Wiesner, J; Lochnit, G; Wygrecka, M; Vilcinskas, A; Preissner, K T

    2015-08-01

    For centuries, maggots have been used for the treatment of wounds by a variety of ancient cultures, as part of their traditional medicine. With increasing appearance of antimicrobial resistance and in association with diabetic ulcers, maggot therapy was revisited in the 1980s. Three mechanisms by which sterile maggots of the green bottle fly Lucilia sericata may improve healing of chronic wounds have been proposed: Biosurgical debridement, disinfecting properties, and stimulation of the wound healing process. However, the influence of maggot excretion products (MEP) on blood coagulation as part of the wound healing process has not been studied in detail. Here, we demonstrate that specific MEP-derived serine proteases from Lucilia sericata induce clotting of human plasma and whole blood, particularly by activating contact phase proteins factor XII and kininogen as well as factor IX, thereby providing kallikrein-bypassing and factor XIa-like activities, both in plasma and in isolated systems. In plasma samples deficient in contact phase proteins, MEP restored full clotting activity, whereas in plasma deficient in either factor VII, IX, X or II no effect was seen. The observed procoagulant/intrinsic pathway-like activity was mediated by (chymo-) trypsin-like proteases in total MEP, which were significantly blocked by C1-esterase inhibitor or other contact phase-specific protease inhibitors. No significant influence of MEP on platelet activation or fibrinolysis was noted. Together, MEP provides contact phase bypassing procoagulant activity and thereby induces blood clotting in the context of wound healing. Further characterisation of the active serine protease(s) may offer new perspectives for biosurgical treatment of chronic wounds. PMID:25948398

  14. Maggot excretion products from the blowfly Lucilia sericata contain contact phase/intrinsic pathway-like proteases with procoagulant functions.

    PubMed

    Kahl, M; Gökçen, A; Fischer, S; Bäumer, M; Wiesner, J; Lochnit, G; Wygrecka, M; Vilcinskas, A; Preissner, K T

    2015-08-01

    For centuries, maggots have been used for the treatment of wounds by a variety of ancient cultures, as part of their traditional medicine. With increasing appearance of antimicrobial resistance and in association with diabetic ulcers, maggot therapy was revisited in the 1980s. Three mechanisms by which sterile maggots of the green bottle fly Lucilia sericata may improve healing of chronic wounds have been proposed: Biosurgical debridement, disinfecting properties, and stimulation of the wound healing process. However, the influence of maggot excretion products (MEP) on blood coagulation as part of the wound healing process has not been studied in detail. Here, we demonstrate that specific MEP-derived serine proteases from Lucilia sericata induce clotting of human plasma and whole blood, particularly by activating contact phase proteins factor XII and kininogen as well as factor IX, thereby providing kallikrein-bypassing and factor XIa-like activities, both in plasma and in isolated systems. In plasma samples deficient in contact phase proteins, MEP restored full clotting activity, whereas in plasma deficient in either factor VII, IX, X or II no effect was seen. The observed procoagulant/intrinsic pathway-like activity was mediated by (chymo-) trypsin-like proteases in total MEP, which were significantly blocked by C1-esterase inhibitor or other contact phase-specific protease inhibitors. No significant influence of MEP on platelet activation or fibrinolysis was noted. Together, MEP provides contact phase bypassing procoagulant activity and thereby induces blood clotting in the context of wound healing. Further characterisation of the active serine protease(s) may offer new perspectives for biosurgical treatment of chronic wounds.

  15. Social identity and the true believer: responses to threatened self-stereotypes among the intrinsically religious.

    PubMed

    Burris, C T; Jackson, L M

    2000-06-01

    That religion is an impactful social category has often been assumed but seldom tested. Based on social identity and self-categorization theories, it is argued that devout religious commitment reflects, at least in part, an individual's motivation to engage in religious self-stereotyping (i.e. to perceive oneself as an exemplary religious group member). In order to test this analysis, individuals scoring high or low on a measure of intrinsic religious orientation received false feedback that either threatened or bolstered their self-perceptions on a dimension of behaviour that was either important or not important to religious group membership. As expected, intrinsic orientation predicted increased religious self-stereotyping only when feedback was threatening and important to religious group membership; affective and behavioural indices revealed a similar pattern. Implications for the social identity/self-categorization literature, and for theory development in the psychology of religion, are subsequently discussed.

  16. Observation of intrinsic size effects in the optical response of individual gold nanoparticles.

    PubMed

    Berciaud, Stéphane; Cognet, Laurent; Tamarat, Philippe; Lounis, Brahim

    2005-03-01

    The photothermal heterodyne imaging method is used to study for the first time the absorption spectra of individual gold nanoparticles with diameters down to 5 nm. Intrinsic size effects that result in a broadening of the surface plasmon resonance are unambiguously observed. Dispersions in the peak energies and homogeneous widths of the single-particle resonances are revealed. The experimental results are analyzed within the frame of Mie theory. PMID:15755105

  17. Green synthesis of bacterial mediated anti-proliferative gold nanoparticles: inducing mitotic arrest (G2/M phase) and apoptosis (intrinsic pathway)

    NASA Astrophysics Data System (ADS)

    Ganesh Kumar, C.; Poornachandra, Y.; Chandrasekhar, Cheemalamarri

    2015-11-01

    The physiochemical and biological properties of microbial derived gold nanoparticles have potential applications in various biomedical domains as well as in cancer therapy. We have fabricated anti-proliferative bacterial mediated gold nanoparticles (b-Au NPs) using a culture supernatant of Streptomyces clavuligerus and later characterized them by UV-visible, TEM, DLS, XRD and FT-IR spectroscopic techniques. The capping agent responsible for the nanoparticle formation was characterized based on SDS-PAGE and MALDI-TOF-MS analyses. They were tested for anticancer activity in A549, HeLa and DU145 cell lines. The biocompatibility and non-toxic nature of the nanoparticles were tested on normal human lung cell line (MRC-5). The b-Au NPs induced the cell cycle arrest in G2/M phase and also inhibited the microtubule assembly in DU145 cells. Mechanistic studies, such as ROS, MMP, Cyt-c, GSH, caspases 9, 8 and 3 activation and the Annexin V-FITC staining, along with the above parameters tested provided sufficient evidence that the b-Au NPs induced apoptosis through the intrinsic pathway. The results supported the use of b-Au NPs for future therapeutic application in cancer therapy and other biomedical applications.The physiochemical and biological properties of microbial derived gold nanoparticles have potential applications in various biomedical domains as well as in cancer therapy. We have fabricated anti-proliferative bacterial mediated gold nanoparticles (b-Au NPs) using a culture supernatant of Streptomyces clavuligerus and later characterized them by UV-visible, TEM, DLS, XRD and FT-IR spectroscopic techniques. The capping agent responsible for the nanoparticle formation was characterized based on SDS-PAGE and MALDI-TOF-MS analyses. They were tested for anticancer activity in A549, HeLa and DU145 cell lines. The biocompatibility and non-toxic nature of the nanoparticles were tested on normal human lung cell line (MRC-5). The b-Au NPs induced the cell cycle arrest in G2

  18. Linear response function of the Mayer bond order: an indicator to describe intrinsic chemical reactivity of molecules

    NASA Astrophysics Data System (ADS)

    Yamanaka, Shusuke; Mitsuta, Yuki; Okumura, Mitsutaka; Yamaguchi, Kizashi; Nakamura, Haruki

    2015-02-01

    We here formulate and implement linear response function (LRF) of the Mayer bond order (MBO), which is expected to be a new indicator to describe intrinsic chemical reactivity of molecules. We calculate LRFs of the MBOs of para-substituted benzoic acids, and compare the results with the Hammett substituent constants and computational results of acid dissociation constants that were previously reported. The results are discussed from the viewpoint of the applicability of LRF of the MBO to estimate the relative reactivity of the substituted benzoic acids.

  19. Catching a ball: contributions of intrinsic muscle stiffness, reflexes, and higher order responses.

    PubMed

    Bennett, D J; Gorassini, M; Prochazka, A

    1994-05-01

    In three sets of experiments in nine normal subjects and a patient with a percutaneous wrist-stabilizing splint, we quantified the open-loop gain (OLG) of the stretch reflex acting about the elbow. The subjects exerted a steady mean flexing force and were instructed not to intervene (i.e., not to resist actively) when force or displacement perturbations were imposed on the forearm. The method was either to reconstruct transmission around the entire loop in a two-part experiment, or to use the attenuation of external perturbations in normal and electrically stimulated muscle to compute gain. Across all experiments, the mean magnitude of stretch reflex OLG was close to unity in the frequency range 1-2 Hz, and declined at higher frequencies, as required to ensure stability, given that the phase lag approached 180 degrees at 5 Hz. Inherent muscle stiffness was approximately equal to reflex stiffness. In functional terms, an OLG of 1 means that the yield caused by a force perturbation is approximately halved by reflex action (prevailing inherent muscle stiffness is doubled). Automatic scaling of reflex transmission at Ia/alpha-motoneuronal synapses ensures that the OLG remains close to unity as inherent stiffness increases. Trials in the patient with the wrist fixator gave similar results, indicating that the reflexes were proprioceptive ly mediated. In a fourth experiment in which the task was to catch a heavy ball, we compared the efficacy of inherent muscle stiffness and reflexes alone, with the subject's intentional reactions, which included predictive and voluntary components of response. The latter were far more effective in maintaining the position of the hand after the ball was caught than inherent and reflex stiffnesses alone. We conclude that stability requirements limit the extent to which stretch reflexes can augment inherent muscle stiffness. When inherent muscle stiffness is low, such as in our ball-catching task, the reflex stiffness is also low, and

  20. The acute phase response in panic disorder.

    PubMed

    Herrán, Andrés; Sierra-Biddle, Deirdre; García-Unzueta, Maria Teresa; Puente, Jesús; Vázquez-Barquero, José Luis; Antonio Amado, José

    2005-12-01

    An acute-phase response (APR), manifested as an increase of acute-phase proteins has been shown in major depression. Panic disorder (PD) may share some aetiopathogenic mechanisms with depression, but APR has not been studied in this disorder. Forty-one panic patients in the first stages of their illness were compared with 32 healthy subjects of comparable sex, age, and body mass index. Clinical diagnosis was established with the mini international neuropsychiatric interview, and severity with the panic disorder severity scale and the CGI scale. Laboratory determinations included four acute phase proteins (APPs) [albumin, gammaglobulins, fibrinogen, C-reactive-protein (CRP)] and basal cortisol level. Patients were studied after 8-wk follow-up taking selective serotonin reuptake inhibitors (SSRIs) to assess the evolution of the APPs. Gammaglobulin levels were lower, and both cortisol and CRP levels were higher in PD patients than in controls. APP did not differ between patients with or without agoraphobia. At follow-up, patients who responded to SSRIs presented a decrease in albumin levels, and a trend towards a decrease in cortisol and CRP compared with levels at intake. The conclusions of this study are that there is an APR in patients suffering from PD, and this APR tends to diminish after a successful treatment with SSRIs. PMID:15927091

  1. Green synthesis of bacterial mediated anti-proliferative gold nanoparticles: inducing mitotic arrest (G2/M phase) and apoptosis (intrinsic pathway).

    PubMed

    Kumar, C Ganesh; Poornachandra, Y; Chandrasekhar, Cheemalamarri

    2015-11-28

    The physiochemical and biological properties of microbial derived gold nanoparticles have potential applications in various biomedical domains as well as in cancer therapy. We have fabricated anti-proliferative bacterial mediated gold nanoparticles (b-Au NPs) using a culture supernatant of Streptomyces clavuligerus and later characterized them by UV-visible, TEM, DLS, XRD and FT-IR spectroscopic techniques. The capping agent responsible for the nanoparticle formation was characterized based on SDS-PAGE and MALDI-TOF-MS analyses. They were tested for anticancer activity in A549, HeLa and DU145 cell lines. The biocompatibility and non-toxic nature of the nanoparticles were tested on normal human lung cell line (MRC-5). The b-Au NPs induced the cell cycle arrest in G2/M phase and also inhibited the microtubule assembly in DU145 cells. Mechanistic studies, such as ROS, MMP, Cyt-c, GSH, caspases 9, 8 and 3 activation and the Annexin V-FITC staining, along with the above parameters tested provided sufficient evidence that the b-Au NPs induced apoptosis through the intrinsic pathway. The results supported the use of b-Au NPs for future therapeutic application in cancer therapy and other biomedical applications. PMID:26503300

  2. p53 Regulates the neuronal intrinsic and extrinsic responses affecting the recovery of motor function following spinal cord injury.

    PubMed

    Floriddia, Elisa M; Rathore, Khizr I; Tedeschi, Andrea; Quadrato, Giorgia; Wuttke, Anja; Lueckmann, Jan-Matthis; Kigerl, Kristina A; Popovich, Phillip G; Di Giovanni, Simone

    2012-10-01

    Following spinal trauma, the limited physiological axonal sprouting that contributes to partial recovery of function is dependent upon the intrinsic properties of neurons as well as the inhibitory glial environment. The transcription factor p53 is involved in DNA repair, cell cycle, cell survival, and axonal outgrowth, suggesting p53 as key modifier of axonal and glial responses influencing functional recovery following spinal injury. Indeed, in a spinal cord dorsal hemisection injury model, we observed a significant impairment in locomotor recovery in p53(-/-) versus wild-type mice. p53(-/-) spinal cords showed an increased number of activated microglia/macrophages and a larger scar at the lesion site. Loss- and gain-of-function experiments suggested p53 as a direct regulator of microglia/macrophages proliferation. At the axonal level, p53(-/-) mice showed a more pronounced dieback of the corticospinal tract (CST) and a decreased sprouting capacity of both CST and spinal serotoninergic fibers. In vivo expression of p53 in the sensorimotor cortex rescued and enhanced the sprouting potential of the CST in p53(-/-) mice, while, similarly, p53 expression in p53(-/-) cultured cortical neurons rescued a defect in neurite outgrowth, suggesting a direct role for p53 in regulating the intrinsic sprouting ability of CNS neurons. In conclusion, we show that p53 plays an important regulatory role at both extrinsic and intrinsic levels affecting the recovery of motor function following spinal cord injury. Therefore, we propose p53 as a novel potential multilevel therapeutic target for spinal cord injury.

  3. Intrinsic diffusion simulation for single-phase multicomponent systems and its application for the analysis of the Darken-Manning and jump frequency formalisms

    NASA Astrophysics Data System (ADS)

    Kulkarni, Nagraj Sheshgiri

    A multicomponent, single-phase, diffusion simulation based on Darken's treatment of intrinsic diffusion has been developed, which provides all the information available from an intrinsic diffusion experiment, including composition profiles and diffusion paths, lattice shifts and velocities, intrinsic and interdiffusion fluxes, as well as fluxes and mean velocities in different frames of reference. The various steps involved in the simulation are discussed and the self-consistency of the simulation is tested with the aid of model systems having constant and variable molar volumes. After an examination of the historical development of the Darken-Manning theories and a brief discussion of previous tests in the literature, a systematic procedure for the comprehensive assessment of these theories is proposed in which the intrinsic diffusion simulation developed in this work occupies a central role. This procedure is then utilized to perform an assessment of the Darken-Manning relations for four binary systems: Ag-Cd, Au-Ni, Cu-Zn and Cu-Ni. It is shown that the Darken-Manning relations that provide the connection between the tracer, intrinsic and interdiffusion coefficients, are unsatisfactory. Hence, it is suggested that the development of multicomponent diffusion databases, which often use the Darken relations for the evaluation of the phenomenological coefficients, may be compromised. As an alternative to the traditional phenomenological formalism of multicomponent diffusion, a kinetic formalism based on atom jump frequencies is proposed. An expression for the intrinsic flux in terms of an unbiased and a biased component is derived. It is demonstrated with the aid of the simulation for the Cu-Zn system, that the biased flux may be evaluated from the experimental intrinsic flux and the unbiased flux (obtained from the tracer jump frequency). An unbiased jump frequency formalism that utilizes effective rather than tracer jump frequencies and avoids the complexities

  4. Inverted optical intrinsic response accompanied by decreased cerebral blood flow are related to both neuronal inhibition and excitation

    PubMed Central

    Ma, Zengguang; Cao, Pengjia; Sun, Pengcheng; Zhao, Linna; Li, Liming; Tong, Shanbao; Lu, Yiliang; Yan, Yan; Chen, Yao; Chai, Xinyu

    2016-01-01

    Negative hemodynamic response has been widely reported in blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging studies, however its origin is still controversial. Optical intrinsic signal (OIS) imaging can be used to study brain activity by simultaneously recording hemodynamic signals at different wavelengths with high spatial resolution. In this study, we found transcorneal electrical stimulation (TcES) could elicit both positive OIS response (POR) and negative OIS response (NOR) in cats’ visual cortex. We then investigated the property of this negative response to TcES and its relationship with cerebral blood flow (CBF) and neuronal activity. Results from laser speckle contrast imaging showed decreased CBF in the NOR region while increased CBF in the POR region. Both planar and laminar electrophysiological recordings in the middle (500–700 μm) cortical layers demonstrated that decreased and increased neuronal activities were coexisted in the NOR region. Furthermore, decreased neuronal activity was also detected in the deep cortical layers in the NOR region. This work provides evidence that the negative OIS together with the decreased CBF should be explained by mechanisms of both neuronal inhibition and excitation within middle cortical layers. Our results would be important for interpreting neurophysiological mechanisms underlying the negative BOLD signals. PMID:26860040

  5. IDO2 Modulates T Cell-Dependent Autoimmune Responses through a B Cell-Intrinsic Mechanism.

    PubMed

    Merlo, Lauren M F; DuHadaway, James B; Grabler, Samantha; Prendergast, George C; Muller, Alexander J; Mandik-Nayak, Laura

    2016-06-01

    Mechanistic insight into how adaptive immune responses are modified along the self-nonself continuum may offer more effective opportunities to treat autoimmune disease, cancer, and other sterile inflammatory disorders. Recent genetic studies in the KRN mouse model of rheumatoid arthritis demonstrate that the immunomodulatory molecule IDO2 modifies responses to self-antigens; however, the mechanisms involved are obscure. In this study, we show that IDO2 exerts a critical function in B cells to support the generation of autoimmunity. In experiments with IDO2-deficient mice, adoptive transplant experiments demonstrated that IDO2 expression in B cells was both necessary and sufficient to support robust arthritis development. IDO2 function in B cells was contingent on a cognate, Ag-specific interaction to exert its immunomodulatory effects on arthritis development. We confirmed a similar requirement in an established model of contact hypersensitivity, in which IDO2-expressing B cells are required for a robust inflammatory response. Mechanistic investigations showed that IDO2-deficient B cells lacked the ability to upregulate the costimulatory marker CD40, suggesting IDO2 acts at the T-B cell interface to modulate the potency of T cell help needed to promote autoantibody production. Overall, our findings revealed that IDO2 expression by B cells modulates autoimmune responses by supporting the cross talk between autoreactive T and B cells.

  6. Cholinergic Responses and Intrinsic Membrane Properties of Developing Thalamic Parafascicular Neurons

    PubMed Central

    Ye, Meijun; Hayar, Abdallah; Garcia-Rill, Edgar

    2009-01-01

    Parafascicular (Pf) neurons receive cholinergic input from the pedunculopontine nucleus (PPN), which is active during waking and REM sleep. There is a developmental decrease in REM sleep in humans between birth and puberty and 10–30 days in rat. Previous studies have established an increase in muscarinic and 5-HT1 serotonergic receptor–mediated inhibition and a transition from excitatory to inhibitory GABAA responses in the PPN during the developmental decrease in REM sleep. However, no studies have been conducted on the responses of Pf cells to the cholinergic input from the PPN during development, which is a major target of ascending cholinergic projections and may be an important mechanism for the generation of rhythmic oscillations in the cortex. Whole cell patch-clamp recordings were performed in 9- to 20-day-old rat Pf neurons in parasagittal slices, and responses to the cholinergic agonist carbachol (CAR) were determined. Three types of responses were identified: inhibitory (55.3%), excitatory (31.1%), and biphasic (fast inhibitory followed by slow excitatory, 6.8%), whereas 6.8% of cells showed no response. The proportion of CAR-inhibited Pf neurons increased with development. Experiments using cholinergic antagonists showed that M2 receptors mediated the inhibitory response, whereas excitatory modulation involved M1, nicotinic, and probably M3 or M5 receptors, and the biphasic response was caused by the activation of multiple types of muscarinic receptors. Compared with CAR-inhibited cells, CAR-excited Pf cells showed 1) a decreased membrane time constant, 2) higher density of hyperpolarization-activated channels (Ih), 3) lower input resistance (Rin), 4) lower action potential threshold, and 5) shorter half-width duration of action potentials. Some Pf cells exhibited spikelets, and all were excited by CAR. During development, we observed decreases in Ih density, Rin, time constant, and action potential half-width. These results suggest that cholinergic

  7. Cholinergic responses and intrinsic membrane properties of developing thalamic parafascicular neurons.

    PubMed

    Ye, Meijun; Hayar, Abdallah; Garcia-Rill, Edgar

    2009-08-01

    Parafascicular (Pf) neurons receive cholinergic input from the pedunculopontine nucleus (PPN), which is active during waking and REM sleep. There is a developmental decrease in REM sleep in humans between birth and puberty and 10-30 days in rat. Previous studies have established an increase in muscarinic and 5-HT1 serotonergic receptor-mediated inhibition and a transition from excitatory to inhibitory GABA(A) responses in the PPN during the developmental decrease in REM sleep. However, no studies have been conducted on the responses of Pf cells to the cholinergic input from the PPN during development, which is a major target of ascending cholinergic projections and may be an important mechanism for the generation of rhythmic oscillations in the cortex. Whole cell patch-clamp recordings were performed in 9- to 20-day-old rat Pf neurons in parasagittal slices, and responses to the cholinergic agonist carbachol (CAR) were determined. Three types of responses were identified: inhibitory (55.3%), excitatory (31.1%), and biphasic (fast inhibitory followed by slow excitatory, 6.8%), whereas 6.8% of cells showed no response. The proportion of CAR-inhibited Pf neurons increased with development. Experiments using cholinergic antagonists showed that M2 receptors mediated the inhibitory response, whereas excitatory modulation involved M1, nicotinic, and probably M3 or M5 receptors, and the biphasic response was caused by the activation of multiple types of muscarinic receptors. Compared with CAR-inhibited cells, CAR-excited Pf cells showed 1) a decreased membrane time constant, 2) higher density of hyperpolarization-activated channels (I(h)), 3) lower input resistance (R(in)), 4) lower action potential threshold, and 5) shorter half-width duration of action potentials. Some Pf cells exhibited spikelets, and all were excited by CAR. During development, we observed decreases in I(h) density, R(in), time constant, and action potential half-width. These results suggest that

  8. Cell Intrinsic and Extrinsic Activators of the Unfolded Protein Response in Cancer: Mechanisms and Targets for Therapy

    PubMed Central

    Tameire, Feven; Verginadis, Ioannis I.; Koumenis, Constantinos

    2015-01-01

    A variety of cell intrinsic or extrinsic stresses evoke perturbations in the folding environment of the endoplasmic reticulum (ER), collectively known as ER stress. Adaptation to stress and reestablishment of ER homeostasis is achieved by activation of an integrated signal transduction pathway called the unfolded protein response (UPR). Both ER stress and UPR activation have been implicated in a variety of human cancers. Although at early stages, or physiological conditions of ER stress, the UPR generally promotes survival, when the stress becomes more stringent or prolonged, its role can switch to a pro-cell death one. Here, we discuss historical and recent evidence supporting an involvement of the UPR in malignancy, describe the main mechanisms by which how tumor cells overcome ER stress to promote their survival, tumor progression and metastasis and discuss the current state of efforts to develop therapeutic approaches of targeting the UPR. PMID:25920797

  9. Resonant Phase Escape from the First Resistive State of Bi2Sr2CaCu2Oy Intrinsic Josephson Junctions under Strong Microwave Irradiation

    NASA Astrophysics Data System (ADS)

    Takahashi, Yusaku; Kakehi, Daiki; Takekoshi, Shuho; Ishikawa, Kazuki; Ayukawa, Shin-ya; Kitano, Haruhisa

    2016-07-01

    We report a study of the phase escape in Bi2Sr2CaCu2Oy intrinsic Josephson junctions under the strong microwave irradiation, focusing on the switch from the first resistive state (2nd SW). The resonant double-peak structure is clearly observed in the switching current distributions below 10 K and is successfully explained by a quantum-mechanical model on the quantum phase escape under the strong microwave field. These results provide the first evidence for the formation of the energy level quantization for the 2nd SW, supporting that the macroscopic quantum tunneling for the 2nd SW survives up to ˜10 K.

  10. On the Firing Rate Dependency of the Phase Response Curve of Rat Purkinje Neurons In Vitro

    PubMed Central

    Couto, João; Linaro, Daniele; De Schutter, E; Giugliano, Michele

    2015-01-01

    Synchronous spiking during cerebellar tasks has been observed across Purkinje cells: however, little is known about the intrinsic cellular mechanisms responsible for its initiation, cessation and stability. The Phase Response Curve (PRC), a simple input-output characterization of single cells, can provide insights into individual and collective properties of neurons and networks, by quantifying the impact of an infinitesimal depolarizing current pulse on the time of occurrence of subsequent action potentials, while a neuron is firing tonically. Recently, the PRC theory applied to cerebellar Purkinje cells revealed that these behave as phase-independent integrators at low firing rates, and switch to a phase-dependent mode at high rates. Given the implications for computation and information processing in the cerebellum and the possible role of synchrony in the communication with its post-synaptic targets, we further explored the firing rate dependency of the PRC in Purkinje cells. We isolated key factors for the experimental estimation of the PRC and developed a closed-loop approach to reliably compute the PRC across diverse firing rates in the same cell. Our results show unambiguously that the PRC of individual Purkinje cells is firing rate dependent and that it smoothly transitions from phase independent integrator to a phase dependent mode. Using computational models we show that neither channel noise nor a realistic cell morphology are responsible for the rate dependent shift in the phase response curve. PMID:25775448

  11. A soybean β-expansin gene GmEXPB2 intrinsically involved in root system architecture responses to abiotic stresses.

    PubMed

    Guo, Wenbing; Zhao, Jing; Li, Xinxin; Qin, Lu; Yan, Xiaolong; Liao, Hong

    2011-05-01

    Root system architecture responds plastically to some abiotic stresses, including phosphorus (P), iron (Fe) and water deficiency, but its response mechanism is still unclear. We cloned and characterized a vegetative β-expansin gene, GmEXPB2, from a Pi starvation-induced soybean cDNA library. Transient expression of 35S::GmEXPB2-GFP in onion epidermal cells verified that GmEXPB2 is a secretory protein located on the cell wall. GmEXPB2 was found to be primarily expressed in roots, and was highly induced by Pi starvation, and the induction pattern was confirmed by GUS staining in transgenic soybean hairy roots. Results from intact soybean composite plants either over-expressing GmEXPB2 or containing knockdown constructs, showed that GmEXPB2 is involved in hairy root elongation, and subsequently affects plant growth and P uptake, especially at low P levels. The results from a heterogeneous transformation system indicated that over-expressing GmEXPB2 in Arabidopsis increased root cell division and elongation, and enhanced plant growth and P uptake at both low and high P levels. Furthermore, we found that, in addition to Pi starvation, GmEXPB2 was also induced by Fe and mild water deficiencies. Taken together, our results suggest that GmEXPB2 is a critical root β-expansin gene that is intrinsically involved in root system architecture responses to some abiotic stresses, including P, Fe and water deficiency. In the case of Pi starvation responses, GmEXPB2 may enhance both P efficiency and P responsiveness by regulating adaptive changes of the root system architecture. This finding has great agricultural potential for improving crop P uptake on both low-P and P-fertilized soils.

  12. Intrinsic and extrinsic heterogeneity in the responses of parent and clonal human colon carcinoma xenografts to photon irradiation

    SciTech Connect

    Leith, J.T.; Bliven, S.F.; Lee, E.S.; Glicksman, A.S.; Dexter, D.L.

    1984-09-01

    Responses to photon irradiation of xenografted human colon tumors derived from the heterogeneous DLD-1 line or its derivative A and D subpopulations were determined using excision assay and tumor regrowth delay assays. Differential responses among the three xenografted carcinomas were demonstrated. Clone A tumors treated with up to 17.5 Gy showed no actual regression below pretreatment volume. In contrast, clone D tumors were sensitive to doses as low as 3.5 Gy, and tumor volumes were reduced by 65% with a dose of 17.5 Gy. The responses of DLD-1 tumors were intermediate between the clone A and clone D tumor responses. Data indicate that the DLD-1 tumors were the most resistant, with clone A of intermediate sensitivity, clone D being the most sensitive tumor. In addition to the interclonal diversity among xenograft lines, intraclonal variation was also observed with clone A (but not clone D or DLD-1) tumors. A biphasic survival curve of cells from clone A xenografts irradiated in air-breathing hosts clearly indicated a minority (approximately 3%) subpopulation of hypoxic cells. Similar results indicating a small percentage of hypoxic cells in clone A solid tumors were obtained from the tumor regrowth delay studies. Also, excision assay data from experiments in which the heterografted carcinomas were irradiated under anoxic conditions support the interpretation that clone A tumors contain a small fraction of hypoxic cells. This study indicates that: (a) heterogeneity in vivo to ionizing radiation exists in the DLD-1 system; and (b) intraclonal variation occurs in vivo due to extrinsic (e.g., environmental hypoxia) factors, such that the intrinsic radioresistance of a subpopulation (clone A) of a heterogeneous human tumor can be further increased.

  13. High-efficiency and fast-response tunable phase grating using a blue phase liquid crystal.

    PubMed

    Yan, Jin; Li, Yan; Wu, Shin-Tson

    2011-04-15

    We demonstrate a tunable phase grating using a polymer-stabilized blue phase liquid crystal. Because of the electric-field-induced rectangularlike phase profile, a high diffraction efficiency of 40% is achieved. Moreover, this device shows submillisecond response time. The proposed tunable phase grating holds great potential for photonics and display applications. PMID:21499371

  14. Microstructure Based Modeling of β Phase Influence on Mechanical Response of Cast AM Series Mg Alloys

    SciTech Connect

    Barker, Erin I.; Choi, Kyoo Sil; Sun, Xin; Deda, Erin; Allison, John; Li, Mei; Forsmark, Joy; Zindel, Jacob; Godlewski, Larry

    2014-09-30

    Magnesium alloys have become popular alternatives to aluminums and steels for the purpose of vehicle light-weighting. However, Mg alloys are hindered from wider application due to limited ductility as well as poor creep and corrosion performance. Understanding the impact of microstructural features on bulk response is key to improving Mg alloys for more widespread use and for moving towards truly predicting modeling capabilities. This study focuses on modeling the intrinsic features, particularly volume fraction and morphology of beta phase present, of cast Mg alloy microstructure and quantifying their impact on bulk performance. Computational results are compared to experimental measurements of cast plates of Mg alloy with varying aluminum content.

  15. Structural ensembles reveal intrinsic disorder for the multi-stimuli responsive bio-mimetic protein Rec1-resilin

    NASA Astrophysics Data System (ADS)

    Balu, Rajkamal; Knott, Robert; Cowieson, Nathan P.; Elvin, Christopher M.; Hill, Anita J.; Choudhury, Namita R.; Dutta, Naba K.

    2015-06-01

    Rec1-resilin is the first recombinant resilin-mimetic protein polymer, synthesized from exon-1 of the Drosophila melanogaster gene CG15920 that has demonstrated unusual multi-stimuli responsiveness in aqueous solution. Crosslinked hydrogels of Rec1-resilin have also displayed remarkable mechanical properties including near-perfect rubber-like elasticity. The structural basis of these extraordinary properties is not clearly understood. Here we combine a computational and experimental investigation to examine structural ensembles of Rec1-resilin in aqueous solution. The structure of Rec1-resilin in aqueous solutions is investigated experimentally using circular dichroism (CD) spectroscopy and small angle X-ray scattering (SAXS). Both bench-top and synchrotron SAXS are employed to extract structural data sets of Rec1-resilin and to confirm their validity. Computational approaches have been applied to these experimental data sets in order to extract quantitative information about structural ensembles including radius of gyration, pair-distance distribution function, and the fractal dimension. The present work confirms that Rec1-resilin is an intrinsically disordered protein (IDP) that displays equilibrium structural qualities between those of a structured globular protein and a denatured protein. The ensemble optimization method (EOM) analysis reveals a single conformational population with partial compactness. This work provides new insight into the structural ensembles of Rec1-resilin in solution.

  16. Switching dynamics and linear response spectra of a driven one-dimensional nonlinear lattice containing an intrinsic localized mode.

    PubMed

    Sato, M; Imai, S; Fujita, N; Shi, W; Takao, Y; Sada, Y; Hubbard, B E; Ilic, B; Sievers, A J

    2013-01-01

    An intrinsic localized mode (ILM) represents a localized vibrational excitation in a nonlinear lattice. Such a mode will stay in resonance as the driver frequency is changed adiabatically until a bifurcation point is reached, at which point the ILM switches and disappears. The dynamics behind switching in such a many body system is examined here through experimental measurements and numerical simulations. Linear response spectra of a driven micromechanical array containing an ILM were measured in the frequency region between two fundamentally different kinds of bifurcation points that separate the large amplitude ILM state from the two low amplitude vibrational states. Just as a natural frequency can be associated with a driven harmonic oscillator, a similar natural frequency has been found for a driven ILM via the beat frequency between it and a weak, tunable probe. This finding has been confirmed using numerical simulations. The behavior of this nonlinear natural frequency plays important but different roles as the two bifurcation points are approached. At the upper transition its frequency coalesces with the driver and the resulting bifurcation is very similar to the saddle-node bifurcation of a single driven Duffing oscillator, which is treated in an Appendix. The lower transition occurs when the four-wave mixing partner of the natural frequency of the ILM intersects the topmost extended band mode of the same symmetry. The properties of linear local modes associated with the driven ILM are also identified experimentally for the first time and numerically but play no role in these transitions. PMID:23410417

  17. Structural ensembles reveal intrinsic disorder for the multi-stimuli responsive bio-mimetic protein Rec1-resilin

    PubMed Central

    Balu, Rajkamal; Knott, Robert; Cowieson, Nathan P.; Elvin, Christopher M.; Hill, Anita J.; Choudhury, Namita R.; Dutta, Naba K.

    2015-01-01

    Rec1-resilin is the first recombinant resilin-mimetic protein polymer, synthesized from exon-1 of the Drosophila melanogaster gene CG15920 that has demonstrated unusual multi-stimuli responsiveness in aqueous solution. Crosslinked hydrogels of Rec1-resilin have also displayed remarkable mechanical properties including near-perfect rubber-like elasticity. The structural basis of these extraordinary properties is not clearly understood. Here we combine a computational and experimental investigation to examine structural ensembles of Rec1-resilin in aqueous solution. The structure of Rec1-resilin in aqueous solutions is investigated experimentally using circular dichroism (CD) spectroscopy and small angle X-ray scattering (SAXS). Both bench-top and synchrotron SAXS are employed to extract structural data sets of Rec1-resilin and to confirm their validity. Computational approaches have been applied to these experimental data sets in order to extract quantitative information about structural ensembles including radius of gyration, pair-distance distribution function, and the fractal dimension. The present work confirms that Rec1-resilin is an intrinsically disordered protein (IDP) that displays equilibrium structural qualities between those of a structured globular protein and a denatured protein. The ensemble optimization method (EOM) analysis reveals a single conformational population with partial compactness. This work provides new insight into the structural ensembles of Rec1-resilin in solution. PMID:26042819

  18. The intrinsic cephalosporin resistome of Listeria monocytogenes in the context of stress response, gene regulation, pathogenesis and therapeutics.

    PubMed

    Krawczyk-Balska, A; Markiewicz, Z

    2016-02-01

    Intrinsic resistance to antibiotics is a serious therapeutic problem in the case of many bacterial species. The Gram-positive human pathogen Listeria monocytogenes is intrinsically resistant to broad spectrum cephalosporin antibiotics, which are commonly used in therapy of bacterial infections. Besides three penicillin-binding proteins the intrinsic cephalosporin resistome of L. monocytogenes includes multidrug resistance transporter transporters, proteins involved in peptidoglycan biosynthesis and modification, cell envelope proteins with structural or general detoxification function, cytoplasmic proteins with unknown function and regulatory proteins. Analysis of the regulation of the expression of genes involved in the intrinsic resistance of L. monocytogenes to cephalosporins highlights the high complexity of control of the intrinsic resistance phenotype. The regulation of the transcription of the intrinsic resistome determinants involves the activity of eight regulators, namely LisR, CesR, LiaR, VirR, σ(B) , σ(H) , σ(L) and PrfA, of which the most prominent role play LisR, CesR and σ(B) . Furthermore, the vast majority of the intrinsic resistome determinants contribute to the tolerance of different stress conditions and virulence. A study indicates that O-acetyltransferase OatA is the most promising candidate for co-drug development since an agent targeting OatA should sensitize L. monocytogenes to certain antibiotics, therefore improving the efficacy of listeriosis treatment as well as food preservation measures.

  19. The MisR Response Regulator Is Necessary for Intrinsic Cationic Antimicrobial Peptide and Aminoglycoside Resistance in Neisseria gonorrhoeae.

    PubMed

    Kandler, Justin L; Holley, Concerta L; Reimche, Jennifer L; Dhulipala, Vijaya; Balthazar, Jacqueline T; Muszyński, Artur; Carlson, Russell W; Shafer, William M

    2016-08-01

    During infection, the sexually transmitted pathogen Neisseria gonorrhoeae (the gonococcus) encounters numerous host-derived antimicrobials, including cationic antimicrobial peptides (CAMPs) produced by epithelial and phagocytic cells. CAMPs have both direct and indirect killing mechanisms and help link the innate and adaptive immune responses during infection. Gonococcal CAMP resistance is likely important for avoidance of host nonoxidative killing systems expressed by polymorphonuclear granulocytes (e.g., neutrophils) and intracellular survival. Previously studied gonococcal CAMP resistance mechanisms include modification of lipid A with phosphoethanolamine by LptA and export of CAMPs by the MtrCDE efflux pump. In the related pathogen Neisseria meningitidis, a two-component regulatory system (2CRS) termed MisR-MisS has been shown to contribute to the capacity of the meningococcus to resist CAMP killing. We report that the gonococcal MisR response regulator but not the MisS sensor kinase is involved in constitutive and inducible CAMP resistance and is also required for intrinsic low-level resistance to aminoglycosides. The 4- to 8-fold increased susceptibility of misR-deficient gonococci to CAMPs and aminoglycosides was independent of phosphoethanolamine decoration of lipid A and the levels of the MtrCDE efflux pump and seemed to correlate with a general increase in membrane permeability. Transcriptional profiling and biochemical studies confirmed that expression of lptA and mtrCDE was not impacted by the loss of MisR. However, several genes encoding proteins involved in membrane integrity and redox control gave evidence of being MisR regulated. We propose that MisR modulates the levels of gonococcal susceptibility to antimicrobials by influencing the expression of genes involved in determining membrane integrity.

  20. The MisR Response Regulator Is Necessary for Intrinsic Cationic Antimicrobial Peptide and Aminoglycoside Resistance in Neisseria gonorrhoeae.

    PubMed

    Kandler, Justin L; Holley, Concerta L; Reimche, Jennifer L; Dhulipala, Vijaya; Balthazar, Jacqueline T; Muszyński, Artur; Carlson, Russell W; Shafer, William M

    2016-08-01

    During infection, the sexually transmitted pathogen Neisseria gonorrhoeae (the gonococcus) encounters numerous host-derived antimicrobials, including cationic antimicrobial peptides (CAMPs) produced by epithelial and phagocytic cells. CAMPs have both direct and indirect killing mechanisms and help link the innate and adaptive immune responses during infection. Gonococcal CAMP resistance is likely important for avoidance of host nonoxidative killing systems expressed by polymorphonuclear granulocytes (e.g., neutrophils) and intracellular survival. Previously studied gonococcal CAMP resistance mechanisms include modification of lipid A with phosphoethanolamine by LptA and export of CAMPs by the MtrCDE efflux pump. In the related pathogen Neisseria meningitidis, a two-component regulatory system (2CRS) termed MisR-MisS has been shown to contribute to the capacity of the meningococcus to resist CAMP killing. We report that the gonococcal MisR response regulator but not the MisS sensor kinase is involved in constitutive and inducible CAMP resistance and is also required for intrinsic low-level resistance to aminoglycosides. The 4- to 8-fold increased susceptibility of misR-deficient gonococci to CAMPs and aminoglycosides was independent of phosphoethanolamine decoration of lipid A and the levels of the MtrCDE efflux pump and seemed to correlate with a general increase in membrane permeability. Transcriptional profiling and biochemical studies confirmed that expression of lptA and mtrCDE was not impacted by the loss of MisR. However, several genes encoding proteins involved in membrane integrity and redox control gave evidence of being MisR regulated. We propose that MisR modulates the levels of gonococcal susceptibility to antimicrobials by influencing the expression of genes involved in determining membrane integrity. PMID:27216061

  1. Extrinsic response enhancement at the polymorphic phase boundary in piezoelectric materials

    NASA Astrophysics Data System (ADS)

    Ochoa, Diego A.; Esteves, Giovanni; Jones, Jacob L.; Rubio-Marcos, Fernando; Fernández, José F.; García, José E.

    2016-04-01

    Polymorphic phase boundaries (PPBs) in piezoelectric materials have attracted significant interest in recent years, in particular, because of the unique properties that can be found in their vicinity. However, to fully harness their potential as micro-nanoscale functional entities, it is essential to achieve reliable and precise control of their piezoelectric response, which is due to two contributions known as intrinsic and extrinsic. In this work, we have used a (K,Na)NbO3-based lead-free piezoceramic as a model system to investigate the evolution of the extrinsic contribution around a PPB. X-ray diffraction measurements are performed over a wide range of temperatures in order to determine the structures and transitions. The relevance of the extrinsic contribution at the PPB region is evaluated by means of nonlinear dielectric response measurements. Though it is widely appreciated that certain intrinsic properties of ferroelectric materials increase as PPBs are approached, our results demonstrate that the extrinsic contribution also maximizes. An enhancement of the extrinsic contribution is therefore also responsible for improving the functional properties at the PPB region. Rayleigh's law is used to quantitatively analyze the nonlinear response. As a result, an evolution of the domain wall motion dynamics through the PPB region is detected. This work demonstrates that the extrinsic contribution at a PPB may have a dynamic role in lead-free piezoelectric materials, thereby exerting a far greater influence on their functional properties than that considered to date.

  2. Dielectric behaviors of Aurivillius Bi5Ti3Fe0.5Cr0.5O15 multiferroic polycrystals: Determining the intrinsic magnetoelectric responses by impedance spectroscopy

    NASA Astrophysics Data System (ADS)

    Bai, Wei; Chen, Chao; Yang, Jing; Zhang, Yuanyuan; Qi, Ruijuan; Huang, Rong; Tang, Xiaodong; Duan, Chun-Gang; Chu, Junhao

    2015-12-01

    Bismuth layer ferroelectrics (BLFs) pioneered by Aurivillius about sixty years ago have been revived recently because of the fatigue- and lead-free behaviors and high Curie temperature, and especially the robust magnetoelectric (ME) effect. However, discerning the intrinsic ME nature, and the inherence between charged defect dipole induced relaxation and spin-related behaviors are still an arduous task. Here, we report a quantitative analysis to reveal the intrinsic spin-lattice coupling in Aurivillius Cr-doped Bi5Ti3FeO15 (BTFCO) multiferroic polycrystals. Dielectric responses are systemically investigated by the temperature-dependent dielectric, module, impedance spectroscopy and equivalent circuit model, and two different dielectric relaxation processes occurred in grain interior of Aurivillius BTFCO polycrystals are clarified. One relaxation is proposed to associate with localized transfer of electrons between Fe3+ and Fe2+ while another one arises from the competition interaction of localized hopping of electrons between Fe3+ and Fe2+ and short-range migration of holes between Cr3+ and Cr6+. The variation of the intrinsic permittivity unambiguously confirms the coupling between spin and dipolar orderings in BTFCO polycrystals. These results offer a vital avenue for identifying the intrinsic and extrinsic signals of the electric and ME responses, and will give significant impetus to exploring the ME electronic devices of Aurivillius materials.

  3. Dielectric behaviors of Aurivillius Bi5Ti3Fe0.5Cr0.5O15 multiferroic polycrystals: Determining the intrinsic magnetoelectric responses by impedance spectroscopy.

    PubMed

    Bai, Wei; Chen, Chao; Yang, Jing; Zhang, Yuanyuan; Qi, Ruijuan; Huang, Rong; Tang, Xiaodong; Duan, Chun-Gang; Chu, Junhao

    2015-01-01

    Bismuth layer ferroelectrics (BLFs) pioneered by Aurivillius about sixty years ago have been revived recently because of the fatigue- and lead-free behaviors and high Curie temperature, and especially the robust magnetoelectric (ME) effect. However, discerning the intrinsic ME nature, and the inherence between charged defect dipole induced relaxation and spin-related behaviors are still an arduous task. Here, we report a quantitative analysis to reveal the intrinsic spin-lattice coupling in Aurivillius Cr-doped Bi(5)Ti(3)FeO(15) (BTFCO) multiferroic polycrystals. Dielectric responses are systemically investigated by the temperature-dependent dielectric, module, impedance spectroscopy and equivalent circuit model, and two different dielectric relaxation processes occurred in grain interior of Aurivillius BTFCO polycrystals are clarified. One relaxation is proposed to associate with localized transfer of electrons between Fe(3+) and Fe(2+) while another one arises from the competition interaction of localized hopping of electrons between Fe(3+) and Fe(2+) and short-range migration of holes between Cr(3+) and Cr(6+). The variation of the intrinsic permittivity unambiguously confirms the coupling between spin and dipolar orderings in BTFCO polycrystals. These results offer a vital avenue for identifying the intrinsic and extrinsic signals of the electric and ME responses, and will give significant impetus to exploring the ME electronic devices of Aurivillius materials.

  4. Dielectric behaviors of Aurivillius Bi5Ti3Fe0.5Cr0.5O15 multiferroic polycrystals: Determining the intrinsic magnetoelectric responses by impedance spectroscopy

    PubMed Central

    Bai, Wei; Chen, Chao; Yang, Jing; Zhang, Yuanyuan; Qi, Ruijuan; Huang, Rong; Tang, Xiaodong; Duan, Chun-Gang; Chu, Junhao

    2015-01-01

    Bismuth layer ferroelectrics (BLFs) pioneered by Aurivillius about sixty years ago have been revived recently because of the fatigue- and lead-free behaviors and high Curie temperature, and especially the robust magnetoelectric (ME) effect. However, discerning the intrinsic ME nature, and the inherence between charged defect dipole induced relaxation and spin-related behaviors are still an arduous task. Here, we report a quantitative analysis to reveal the intrinsic spin-lattice coupling in Aurivillius Cr-doped Bi5Ti3FeO15 (BTFCO) multiferroic polycrystals. Dielectric responses are systemically investigated by the temperature-dependent dielectric, module, impedance spectroscopy and equivalent circuit model, and two different dielectric relaxation processes occurred in grain interior of Aurivillius BTFCO polycrystals are clarified. One relaxation is proposed to associate with localized transfer of electrons between Fe3+ and Fe2+ while another one arises from the competition interaction of localized hopping of electrons between Fe3+ and Fe2+ and short-range migration of holes between Cr3+ and Cr6+. The variation of the intrinsic permittivity unambiguously confirms the coupling between spin and dipolar orderings in BTFCO polycrystals. These results offer a vital avenue for identifying the intrinsic and extrinsic signals of the electric and ME responses, and will give significant impetus to exploring the ME electronic devices of Aurivillius materials. PMID:26639998

  5. Stimuli-Responsive Cubosomes Formed from Blue Phase Liquid Crystals.

    PubMed

    Bukusoglu, Emre; Wang, Xiaoguang; Martinez-Gonzalez, Jose A; de Pablo, Juan J; Abbott, Nicholas L

    2015-11-18

    Cubosomes formed from blue phase liquid crystals (BPs) dispersed in aqueous media exhibit optical responses to biological amphiphiles. In this study, the formation of aqueous dispersions of BPs is reported, and the effects of confinement and lipids on the phase behavior, optical appearance, and morphology of BP droplets are characterized.

  6. Intrinsic spontaneous emission-induced fluctuations of the output optical beam power and phase in a diode amplifier

    NASA Astrophysics Data System (ADS)

    Bogatov, A. P.; Drakin, A. E.; D'yachkov, N. V.; Gushchik, T. I.

    2016-08-01

    Output optical beam intensity and phase fluctuations are analysed in a classical approach to describing the propagation and amplification of spontaneous emission in the active region of a laser diode with a gain saturated by input monochromatic light. We find their spectral densities and dispersion and the correlation coefficient of the two-dimensional probability distribution function of the fluctuations.

  7. Observation of intrinsic Josephson effects in tetragonally synthesized single-crystalline NdBa2Cu3O6.65 films grown by tri-phase epitaxy

    NASA Astrophysics Data System (ADS)

    Yun, Kyung Sung; Hatano, Takeshi; Arisawa, Shunichi; Ishii, Akira; Wang, Huabing; Yamashita, Tsutomu; Iguchi, Ienari; Kawasaki, Masashi; Koinuma, Hideomi

    2008-07-01

    In this work twin-free tetragonal NdBa2Cu3O7-δ films were fabricated that exhibited superconductivity with sufficient anisotropy which produced intrinsic Josephson junction (IJJ) characteristics in the films. The intrinsic Josephson effects (IJEs) were observed in oxygen-deficient single-crystalline NdBa2Cu3O6.65 (NBCO) films grown on SrTiO3 (STO) substrates, using tri-phase epitaxy (TPE). The single-crystalline nature of NBCO films on well-matched STO substrates, and the precisely controlled oxygen content of the films, lead to the IJEs of the thin films. Furthermore, the films exhibit high anisotropy and clear multiple-branch structures, with hysteresis observed in the current-voltage characteristics. Periodic Josephson vortex-flow resistance oscillations were also observed for a magnetic field higher than 64 kOe, which was applied normal to the junctions. These results strongly support the single-crystal nature of TPE films, which play an important role in both the fundamental study and the practical applications of high-frequency devices.

  8. Low frequency cabin noise reduction based on the intrinsic structural tuning concept: The theory and the experimental results, phase 2. [jet aircraft noise

    NASA Technical Reports Server (NTRS)

    Sengupta, G.

    1978-01-01

    Low frequency cabin noise and sonically induced stresses in an aircraft fuselage may be reduced by intrinsic tuning of the various structural members such as the skin, stringers, and frames and then applying damping treatments on these members. The concept is also useful in identifying the key structural resonance mechanisms controlling the fuselage response to broadband random excitation and in developing suitable damping treatments for reducing the structural response in various frequency ranges. The mathematical proof of the concept and the results of some laboratory and field tests on a group of skin-stringer panels are described. In the so-called stiffness-controlled region, the noise transmission may actually be controlled by stiffener resonances, depending upon the relationship between the natural frequencies of the skin bay and the stiffeners. Therefore, cabin noise in the stiffness-controlled region may be effectively reduced by applying damping treatments on the stiffeners.

  9. Cephalic phase responses to sweet taste.

    PubMed

    Abdallah, L; Chabert, M; Louis-Sylvestre, J

    1997-03-01

    The sweet taste of nonnutritive sweeteners has been reported to increase hunger and food intake through the mechanism of cephalic-phase insulin release (CPIR). We investigated the effect of oral sensation of sweetness on CPIR and other indexes associated with glucose metabolism using nutritive and nonnutritive sweetened tablets as stimuli. At lunchtime, 12 normal-weight men sucked for 5 min a sucrose, an aspartame-polydextrose, or an unsweetened polydextrose tablet (3 g) with no added flavor. The three stimuli were administered in a counterbalanced order, each on a separate day at 1-wk intervals. Blood was drawn continuously for 45 min before and 25 min after the beginning of sucking and samples were collected at 1-min intervals. Spontaneous oscillations in glucose, insulin, and glucagon concentrations were assessed as were increments (slopes) of fatty acid concentrations during the baseline period. The nature of the baseline (oscillations: glucose, insulin, and glucagon; and slopes: fatty acids) was taken into account in the analyses of postexposure events. No CPIR and no significant effect on plasma glucagon or fatty acid concentrations were observed after the three stimuli. However, there was a significant decrease in plasma glucose and insulin after all three stimuli. Only the consumption of the sucrose tablet was followed by a postabsorptive increase in plasma glucose and insulin concentrations starting 17 and 19 min, respectively, after the beginning of sucking. In conclusion, this study suggested that oral stimulation provided by sweet nonflavored tablets is not sufficient for inducing CPIR.

  10. Direct observation of nanoscale interface phase in the superconducting chalcogenide KxFe2 -ySe2 with intrinsic phase separation

    NASA Astrophysics Data System (ADS)

    Ricci, A.; Poccia, N.; Joseph, B.; Innocenti, D.; Campi, G.; Zozulya, A.; Westermeier, F.; Schavkan, A.; Coneri, F.; Bianconi, A.; Takeya, H.; Mizuguchi, Y.; Takano, Y.; Mizokawa, T.; Sprung, M.; Saini, N. L.

    2015-01-01

    We have used scanning micro x-ray diffraction to characterize different phases in superconducting KxFe2 -ySe2 as a function of temperature, unveiling the thermal evolution across the superconducting transition temperature (Tc˜32 K), phase separation temperature (Tp s˜520 K), and iron-vacancy order temperature (Tv o˜580 K). In addition to the iron-vacancy ordered tetragonal magnetic phase and orthorhombic metallic minority filamentary phase, we have found clear evidence of the interface phase with tetragonal symmetry. The metallic phase is surrounded by this interface phase below ˜300 K, and is embedded in the insulating texture. The spatial distribution of coexisting phases as a function of temperature provides clear evidence of the formation of protected metallic percolative paths in the majority texture with large magnetic moment, required for the electronic coherence for the superconductivity. Furthermore, a clear reorganization of iron-vacancy order around the Tp s and Tc is found with the interface phase being mostly associated with a different iron-vacancy configuration, that may be important for protecting the percolative superconductivity in KxFe2 -ySe2 .

  11. The acidity and proton affinity of the damaged base 1,N6-ethenoadenine in the gas phase versus in solution: intrinsic reactivity and biological implications.

    PubMed

    Liu, Min; Xu, Meng; Lee, Jeehiun K

    2008-08-01

    1,N(6)-ethenoadenine (epsilonA) is a highly mutagenic lesion that is excised from human DNA by the enzyme alkyladenine DNA glycosylase (AAG). In an effort to understand the intrinsic properties of 1,N(6)-ethenoadenine, we examined its gas phase acidity and proton affinity using quantum mechanical calculations and mass spectrometric experimental methods. We measure two acidities for epsilonA: a more acidic site (DeltaH(acid) = 332 kcal mol(-1); DeltaG(acid) = 325 kcal mol(-1)) and a less acidic site (DeltaH(acid) = 367 kcal mol(-1); DeltaG(acid) = 360 kcal mol(-1)). We also find that the proton affinity of the most basic site of 1,N(6)-ethenoadenine is 232-233 kcal mol(-1) (GB = 224 kcal mol(-1)). These measurements, when compared to calculations, establish that, under our experimental conditions, we have only the canonical tautomer of 1,N(6)-ethenoadenine present. We also compare the gas phase acidic properties of epsilonA with that of the normal bases adenine and guanine and find that epsilonA is the most acidic. This supports the theory that AAG and other related enzymes may cleave damaged bases as anions. Furthermore, comparison of the gas phase and aqueous acidities indicates that the nonpolar environment of the enzyme enhances the acidity differences of epsilonA versus adenine and guanine. PMID:18593189

  12. Glassy phases and driven response of the phase-field-crystal model with random pinning.

    PubMed

    Granato, E; Ramos, J A P; Achim, C V; Lehikoinen, J; Ying, S C; Ala-Nissila, T; Elder, K R

    2011-09-01

    We study the structural correlations and the nonlinear response to a driving force of a two-dimensional phase-field-crystal model with random pinning. The model provides an effective continuous description of lattice systems in the presence of disordered external pinning centers, allowing for both elastic and plastic deformations. We find that the phase-field crystal with disorder assumes an amorphous glassy ground state, with only short-ranged positional and orientational correlations, even in the limit of weak disorder. Under increasing driving force, the pinned amorphous-glass phase evolves into a moving plastic-flow phase and then, finally, a moving smectic phase. The transverse response of the moving smectic phase shows a vanishing transverse critical force for increasing system sizes. PMID:22060323

  13. Glassy phases and driven response of the phase-field-crystal model with random pinning.

    PubMed

    Granato, E; Ramos, J A P; Achim, C V; Lehikoinen, J; Ying, S C; Ala-Nissila, T; Elder, K R

    2011-09-01

    We study the structural correlations and the nonlinear response to a driving force of a two-dimensional phase-field-crystal model with random pinning. The model provides an effective continuous description of lattice systems in the presence of disordered external pinning centers, allowing for both elastic and plastic deformations. We find that the phase-field crystal with disorder assumes an amorphous glassy ground state, with only short-ranged positional and orientational correlations, even in the limit of weak disorder. Under increasing driving force, the pinned amorphous-glass phase evolves into a moving plastic-flow phase and then, finally, a moving smectic phase. The transverse response of the moving smectic phase shows a vanishing transverse critical force for increasing system sizes.

  14. Intrinsic MyD88-Akt1-mTOR Signaling Coordinates Disparate Tc17 and Tc1 Responses during Vaccine Immunity against Fungal Pneumonia.

    PubMed

    Nanjappa, Som Gowda; Hernández-Santos, Nydiaris; Galles, Kevin; Wüthrich, Marcel; Suresh, M; Klein, Bruce S

    2015-09-01

    Fungal infections have skyrocketed in immune-compromised patients lacking CD4+ T cells, underscoring the need for vaccine prevention. An understanding of the elements that promote vaccine immunity in this setting is essential. We previously demonstrated that vaccine-induced IL-17A+ CD8+ T cells (Tc17) are required for resistance against lethal fungal pneumonia in CD4+ T cell-deficient hosts, whereas the individual type I cytokines IFN-γ, TNF-α and GM-CSF, are dispensable. Here, we report that T cell-intrinsic MyD88 signals are crucial for these Tc17 cell responses and vaccine immunity against lethal fungal pneumonia in mice. In contrast, IFN-γ+ CD8+ cell (Tc1) responses are largely normal in the absence of intrinsic MyD88 signaling in CD8+ T cells. The poor accumulation of MyD88-deficient Tc17 cells was not linked to an early onset of contraction, nor to accelerated cell death or diminished expression of anti-apoptotic molecules Bcl-2 or Bcl-xL. Instead, intrinsic MyD88 was required to sustain the proliferation of Tc17 cells through the activation of mTOR via Akt1. Moreover, intrinsic IL-1R and TLR2, but not IL-18R, were required for MyD88 dependent Tc17 responses. Our data identify unappreciated targets for augmenting adaptive immunity against fungi. Our findings have implications for designing fungal vaccines and immune-based therapies in immune-compromised patients.

  15. Response in the late phase to a radiological emergency.

    PubMed

    Morrey, Mary; Nisbet, Anne; Thome, Daryl; Savkin, Michael; Hoe, Steen; Brynildsen, Lisbeth

    2004-01-01

    This paper looks at the key issues that need to be addressed during the transition from the emergency phase to the late phase of a radioactive release, and the development of the initial late phase strategy. It discusses the extent to which current national plans and international advice address the needs of decision makers following contamination of inhabited areas and food production systems. Based on this the following recommendations are made: (1) the issues that will arise at the start of the late phase response to a radioactive release require preparation work in advance of any release; (2) this preparation should consider the adequacy of legislation, technical data and modelling, options for waste storage and disposal, resources for monitoring and implementing clean up; (3) late phase preparedness requires regular exercising and (4) the possibility of terrorist releases adds further emphasis to the need for preparedness for the late phase.

  16. Adaptive optics and phase diversity imaging for responsive space applications.

    SciTech Connect

    Smith, Mark William; Wick, David Victor

    2004-11-01

    The combination of phase diversity and adaptive optics offers great flexibility. Phase diverse images can be used to diagnose aberrations and then provide feedback control to the optics to correct the aberrations. Alternatively, phase diversity can be used to partially compensate for aberrations during post-detection image processing. The adaptive optic can produce simple defocus or more complex types of phase diversity. This report presents an analysis, based on numerical simulations, of the efficiency of different modes of phase diversity with respect to compensating for specific aberrations during post-processing. It also comments on the efficiency of post-processing versus direct aberration correction. The construction of a bench top optical system that uses a membrane mirror as an active optic is described. The results of characterization tests performed on the bench top optical system are presented. The work described in this report was conducted to explore the use of adaptive optics and phase diversity imaging for responsive space applications.

  17. Phase resetting for a network of oscillators via phase response curve approach.

    PubMed

    Efimov, D

    2015-02-01

    The problem of phase regulation for a population of oscillating systems is considered. The proposed control strategy is based on a phase response curve (PRC) model of an oscillator (the first-order reduced model obtained for linearized system and inputs with infinitesimal amplitude). It is proven that the control provides phase resetting for the original nonlinear system. Next, the problem of phase resetting for a network of oscillators is considered when applying a common control input. Performance of the obtained solutions is demonstrated via computer simulation for three different models of circadian/neural oscillators. PMID:25246107

  18. Spectral response of the intrinsic region of a GaAs-InAs quantum dot solar cell considering the absorption spectra of ideal cubic dots

    NASA Astrophysics Data System (ADS)

    Biswas, Sayantan; Chatterjee, Avigyan; Biswas, Ashim Kumar; Sinha, Amitabha

    2016-10-01

    Recently, attempts have been made by some researchers to improve the efficiency of quantum dot solar cells by incorporating different types of quantum dots. In this paper, the photocurrent density has been obtained considering the absorption spectra of ideal cubic dots. The effects of quantum dot size dispersion on the spectral response of the intrinsic region of a GaAs-InAs quantum dot solar cell have been studied. The dependence of the spectral response of this region on the size of quantum dots of such solar cell has also been investigated. The investigation shows that for smaller quantum dot size dispersion, the spectral response of the intrinsic region of the cell increases significantly. It is further observed that by enlarging the quantum dot size it is possible to enhance the spectral response of such solar cells as it causes better match between absorption spectra of the quantum dots and the solar spectrum. These facts indicate the significant role of quantum dot size and size dispersion on the performance of such devices. Also, the power conversion efficiency of such solar cell has been studied under 1 sun, AM 1.5 condition.

  19. Improved stability and cell response by intrinsic cross-linking of multilayers from collagen I and oxidized glycosaminoglycans.

    PubMed

    Zhao, Mingyan; Li, Lihua; Zhou, Changren; Heyroth, Frank; Fuhrmann, Bodo; Maeder, Karsten; Groth, Thomas

    2014-11-10

    Stability of surface coatings against environmental stress, such as pH, high ionic strength, mechanical forces, and so forth, is crucial for biomedical application of implants. Here, a novel extracellular-matrix-like polyelectrolyte multilayer (PEM) system composed of collagen I (Col I) and oxidized glycosaminoglycans (oGAGs) was stabilized by intrinsic cross-linking due to formation of imine bonds between aldehydes of oxidized chondroitin sulfate (oCS) or hyaluronan (oHA) and amino groups of Col I. It was also found that Col I contributed significantly more to overall mass in CS-Col I than in HA-Col I multilayer systems and fibrillized particularly in the presence of native and oxidized CS. Adhesion and proliferation studies with murine C3H10T1/2 embryonic fibroblasts demonstrated that covalent cross-linking of oGAG with Col I had no adverse effects on cell behavior. By contrast, it was found that cell size and polarization was more pronounced on oGAG-based multilayer systems, which corresponded also to the higher stiffness of cross-linked multilayers as observed by studies with quartz crystal microbalance (QCM). Overall, PEMs prepared from oGAG and Col I give rise to stable PEM constructs due to intrinsic cross-linking that may be useful for making bioactive coatings of implants and tissue engineering scaffolds.

  20. Determining individual phase response curves from aggregate population data

    NASA Astrophysics Data System (ADS)

    Wilson, Dan; Moehlis, Jeff

    2015-08-01

    Phase reduction is an invaluable technique for investigating the dynamics of nonlinear limit cycle oscillators. Central to the implementation of phase reduction is the ability to calculate phase response curves (PRCs), which describe an oscillator's response to an external perturbation. Current experimental techniques for inferring PRCs require data from individual oscillators, which can be impractical to obtain when the oscillator is part of a much larger population. Here we present a simple methodology to calculate PRCs of individual oscillators using an aggregate signal from a large homogeneous population. This methodology is shown to be accurate in the presence of interoscillator coupling and noise and can also provide a good estimate of an average PRC of a heterogeneous population. We also find that standard experimental techniques for PRC measurement can produce misleading results when applied to aggregate population data.

  1. Response of two-phase droplets to intense electromagnetic radiation

    NASA Technical Reports Server (NTRS)

    Spann, James F.; Maloney, Daniel J.; Lawson, William F.; Casleton, Kent H.

    1993-01-01

    The response of two-phase droplets to intense radiant heating is studied to determine the incident power that is required for causing explosive boiling in the liquid phase. The droplets studied consist of strongly absorbing coal particles dispersed in a weakly absorbing water medium. Experiments are performed by confining droplets (radii of 37, 55, and 80 microns) electrodynamically and irradiating them from two sides with pulsed laser beams. Emphasis is placed on the transition region from accelerated droplet vaporization to droplet superheating and explosive boiling. The time scale observed for explosive boiling is more than 2 orders of magnitude longer than published values for pure liquids. The delayed response is the result of energy transfer limitations between the absorbing solid phase and the surrounding liquid.

  2. Phase responses of harmonics reflected from radio-frequency electronics

    NASA Astrophysics Data System (ADS)

    Mazzaro, Gregory J.; McGowan, Sean F.; Gallagher, Kyle A.; Sherbondy, Kelly D.; Martone, Anthony F.; Narayanan, Ram M.

    2016-05-01

    The phase responses of nonlinear-radar targets illuminated by stepped frequencies are studied. Data is presented for an experimental radar and two commercial electronic targets at short standoff ranges. The amplitudes and phases of harmonics generated by each target at each frequency are captured over a 100-MHz-wide transmit band. As in the authors' prior work, target detection is demonstrated by receiving at least one harmonic of at least one transmit frequency. In the present work, experiments confirm that the phase of a harmonic reflected from a radio-frequency electronic target at a standoff distance is linear versus frequency. Similar to traditional wideband radar, the change of the reflected phase with respect to frequency indicates the range to the nonlinear target.

  3. [Modeling and simulation of responses from ultrasonic linear phased array].

    PubMed

    He, Wenjing; Zhu, Yuanzhong; Wang, Yufeng; He, Lingli; Lai, Siyu

    2012-10-01

    Phased array transducers are very attractive because the beam generated by the arrays can be electronically focused and steered. The present work characterizes far-field 2D properties of phased array system by functions that are deduced from rectangle source, rectangle line array and phased array based on point source. Results are presented for the distribution of ultrasound intensity on plane xoz and on x-axis by simulation using numerical calculation. It is shown that the shape of response of rectangle line array is modulated by the single array element. It is also demonstrated that the delay time of phased array is the key to steer the beam, sacrificing the value of main lobe and increasing the number of side lobes.

  4. Theoretical study on single-phase stability and intrinsic defects in different Cu2ZnSn(Se1-xSx)4 alloys

    NASA Astrophysics Data System (ADS)

    Sarker, Pranab; Huda, Muhammad N.

    2015-03-01

    Cu2ZnSn(Se1-xSx)4 (CZTSSe) alloy has been emerged as a potential next generation commercialized photovoltaic cell because of its higher solar-to-current efficiency (12.6 %) over parent compounds Cu2ZnSnS4(CZTS)andCu2ZnSnSe4 (CZTSe). However, the values of composition x in higher efficient CZTSSe (>11%) are not known yet. It has been inferred from the recent theoretical and experimental evidences that 0.375 <= x <= 0.625 (x = alloy ratio per unit cell) could be the range that poses to ensure higher PV efficiency in CZTSSe. The crystal structure of CZTSSe at those x values were determined using density functional theory. In addition, the probability of forming different intrinsic defects in those different CZTSSe alloys were evaluated at various growth conditions determined from chemical potential landscape analysis for the first time. Chemical potential landscape analysis further reveals that CZTSSe alloys have higher single phase stability than that of their parent structures. This work is partially supported by NREL.

  5. A Cell Line Producing Recombinant Nerve Growth Factor Evokes Growth Responses in Intrinsic and Grafted Central Cholinergic Neurons

    NASA Astrophysics Data System (ADS)

    Ernfors, Patrik; Ebendal, Ted; Olson, Lars; Mouton, Peter; Stromberg, Ingrid; Persson, Hakan

    1989-06-01

    The rat β nerve growth factor (NGF) gene was inserted into a mammalian expression vector and cotransfected with a plasmid conferring resistance to neomycin into mouse 3T3 fibroblasts. From this transfection a stable cell line was selected that contains several hundred copies of the rat NGF gene and produces excess levels of recombinant NGF. Such genetically modified cells were implanted into the rat brain as a probe for in vivo effects of NGF on central nervous system neurons. In a model of the cortical cholinergic deficits in Alzheimer disease, we demonstrate a marked increase in the survival of, and fiber outgrowth from, grafts of fetal basal forebrain cholinergic neurons, as well as stimulation of fiber formation by intact adult intrinsic cholinergic circuits in the cerebral cortex. Adult cholinergic interneurons in intact striatum also sprout vigorously toward implanted fibroblasts. Our results suggest that this model has implications for future treatment of neurodegenerative diseases.

  6. Development and implementation of a stereoselective normal-phase liquid chromatography-tandem mass spectrometry method for the determination of intrinsic metabolic clearance in human liver microsomes.

    PubMed

    Zhang, Yingru; Caporuscio, Christian; Dai, Jun; Witkusa, Michael; Rose, Anne; Santella, Joseph; D'Arienzo, Celia; Wang-Iverson, David B; Tymiak, Adrienne A

    2008-11-01

    The stereoselective determination of stereoisomers in biological samples provides vital information on stereospecific metabolism and pharmacokinetic profiles of the drugs. Despite the unique advantage and the great success of normal-phase (NP) HPLC for the separations of drug stereoisomers using polysaccharide-type chiral stationary phases (CSPs), the technique is rarely applied to quantitative HPLC-MS-MS bioanalysis. This is, at least in part, due to the incompatibility between the usual mobile phase (n-hexane or n-heptane) in normal-phase HPLC and the MS ionization sources which poses a potential detonation hazard. An environmentally friendly and nonflammable alternative solvent, ethoxynonafluorobutane (ENFB), was reported previously to potentially provide an ideal solution for combining the powers of stereoselective NP chromatographic separation and MS-MS detection. In this study, a stereoselective NP-HPLC-MS-MS method was developed using ENFB to quantify a pair of Bristol Myers Squibb (BMS) proprietary drug stereoisomers and their ketone metabolite for an in vitro study, which demonstrated, for the first time, the practical applicability and utility of ENFB for bioanalysis in pharmaceutical industry. The effects of different organic modifiers and temperature, as well as the comparison between ENFB and the usual solvent, heptane, for the separation, are discussed. The resolution of the stereoisomers was achieved using 63% of 3:1 mixture of ethanol and methanol with 37% ENFB on a Chiralpak AD-H column at 50 degrees C. High sensitivity was obtained using the MS-MS detection in the positive ion atmospheric pressure chemical ionization (APCI) mode. The lower limit of quantitation (LLOQ) for the first stereoisomer and the ketone metabolite was 5 ng/mL, and was 10 ng/mL for the second isomer in the human liver microsome-potassium phosphate buffer matrix. The linear dynamic range of 5-1000 ng/mL for both isomers and 10-1000 ng/mL for the metabolite were demonstrated

  7. Phase response curves in the characterization of epileptiform activity

    NASA Astrophysics Data System (ADS)

    Perez Velazquez, J. L.; Galán, R. F.; Dominguez, L. Garcia; Leshchenko, Y.; Lo, S.; Belkas, J.; Erra, R. Guevara

    2007-12-01

    Coordinated cellular activity is a major characteristic of nervous system function. Coupled oscillator theory offers unique avenues to address cellular coordination phenomena. In this study, we focus on the characterization of the dynamics of epileptiform activity, based on some seizures that manifest themselves with very periodic rhythmic activity, termed absence seizures. Our approach consists in obtaining experimentally the phase response curves (PRCs) in the neocortex and thalamus, and incorporating these PRCs into a model of coupled oscillators. Phase preferences of the stationary states and their stability are determined, and these results from the model are compared with the experimental recordings, and interpreted in physiological terms.

  8. Prestimulation phase predicts the TMS-evoked response.

    PubMed

    Kundu, Bornali; Johnson, Jeffrey S; Postle, Bradley R

    2014-10-15

    Prestimulation oscillatory phase and power in particular frequency bands predict perception of at-threshold visual stimuli and of transcranial magnetic stimulation (TMS)-induced phosphenes. These effects may be due to changes in cortical excitability, such that certain ranges of power and/or phase values result in a state in which a particular brain area is more receptive to input, thereby biasing behavior. However, the effects of trial-by-trial fluctuations in phase and power of ongoing oscillations on the brain's electrical response to TMS itself have thus far not been addressed. The present study adopts a combined TMS and electroencepalography (EEG) approach to determine whether the TMS-evoked response is sensitive to momentary fluctuations in prestimulation phase and/or power in different frequency bands. Specifically, TMS was applied to superior parietal lobule while subjects performed a short-term memory task. Results showed that the prestimulation phase, particularly within the beta (15-25 Hz) band, predicted pulse-by-pulse variations in the global mean field amplitude. No such relationship was observed between prestimulation power and the global mean field amplitude. Furthermore, TMS-evoked power in the beta band fluctuated with prestimulation phase in the beta band in a manner that differed from spontaneous brain activity. These effects were observed in areas at and distal to the stimulation site. Together, these results confirm the idea that fluctuating phase of ongoing neuronal oscillations create "windows of excitability" in the brain, and they give insight into how TMS interacts with ongoing brain activity on a pulse-by-pulse basis.

  9. Acid tolerance response of Bordetella bronchiseptica in avirulent phase.

    PubMed

    Fingermann, M; Hozbor, D

    2015-12-01

    Bordetella bronchiseptica is a Gram-negative bacterium responsible for respiratory diseases in many mammalian hosts, including humans. This pathogen has been shown as able to persist inside the host cells, even in the phagosomes that are acidified to pH 4.5-5.0 after bacterial infection. Here we evaluated the resistance of B. bronchiseptica to survive under acidic conditions. In particular we analyzed the bacterial capacity to develop the mechanism known as acid tolerance response (ATR). Our studies were mainly focused on the avirulent phase of the bacteria since this phenotypic phase was reported to be more resistant to environmental stress conditions than the virulent phase. Results from B. bronchiseptica in virulent phase were also included for comparison purposes. In fact, for B. bronchiseptica 9.73 bacteria in virulent phase we observed that the viability of bacteria does not decrease significantly when grown at pH as low as 4.5, but it is affected when the pH of the medium was equal to or less than 4.0. After acid-adaptation at pH 5.5 for several hours, the survival rate of B. bronchiseptica 9.73 at lethal pH 4.0 for 6h was increased. Interestingly, the avirulent phase mediated by the two-component BvgAS system conferred further resistance to lethal acid challenge and a marked increase in the magnitude of the expressed ATR. The ATR for this avirulent phase seems to be associated with changes in LPS and surface protein profiles. 2D-gel electrophoresis revealed at least 25 polypeptides differentially expressed, 17 of which were only expressed or over-expressed under acid conditions. Using MALDI-TOF mass spectrometry, 10 of these differentially expressed polypeptides were identified. PMID:26640052

  10. Acid tolerance response of Bordetella bronchiseptica in avirulent phase.

    PubMed

    Fingermann, M; Hozbor, D

    2015-12-01

    Bordetella bronchiseptica is a Gram-negative bacterium responsible for respiratory diseases in many mammalian hosts, including humans. This pathogen has been shown as able to persist inside the host cells, even in the phagosomes that are acidified to pH 4.5-5.0 after bacterial infection. Here we evaluated the resistance of B. bronchiseptica to survive under acidic conditions. In particular we analyzed the bacterial capacity to develop the mechanism known as acid tolerance response (ATR). Our studies were mainly focused on the avirulent phase of the bacteria since this phenotypic phase was reported to be more resistant to environmental stress conditions than the virulent phase. Results from B. bronchiseptica in virulent phase were also included for comparison purposes. In fact, for B. bronchiseptica 9.73 bacteria in virulent phase we observed that the viability of bacteria does not decrease significantly when grown at pH as low as 4.5, but it is affected when the pH of the medium was equal to or less than 4.0. After acid-adaptation at pH 5.5 for several hours, the survival rate of B. bronchiseptica 9.73 at lethal pH 4.0 for 6h was increased. Interestingly, the avirulent phase mediated by the two-component BvgAS system conferred further resistance to lethal acid challenge and a marked increase in the magnitude of the expressed ATR. The ATR for this avirulent phase seems to be associated with changes in LPS and surface protein profiles. 2D-gel electrophoresis revealed at least 25 polypeptides differentially expressed, 17 of which were only expressed or over-expressed under acid conditions. Using MALDI-TOF mass spectrometry, 10 of these differentially expressed polypeptides were identified.

  11. Evaluation of the Phase-Dependent Rhythm Control of Human Walking Using Phase Response Curves

    PubMed Central

    Yamamoto, Yuki; Aoi, Shinya; Imai, Takashi; Aoyagi, Toshio; Tomita, Nozomi; Tsuchiya, Kazuo

    2016-01-01

    Humans and animals control their walking rhythms to maintain motion in a variable environment. The neural mechanism for controlling rhythm has been investigated in many studies using mechanical and electrical stimulation. However, quantitative evaluation of rhythm variation in response to perturbation at various timings has rarely been investigated. Such a characteristic of rhythm is described by the phase response curve (PRC). Dynamical simulations of human skeletal models with changing walking rhythms (phase reset) described a relation between the effective phase reset on stability and PRC, and phase reset around touch-down was shown to improve stability. A PRC of human walking was estimated by pulling the swing leg, but such perturbations hardly influenced the stance leg, so the relation between the PRC and walking events was difficult to discuss. This research thus examines human response to variations in floor velocity. Such perturbation yields another problem, in that the swing leg is indirectly (and weakly) perturbed, so the precision of PRC decreases. To solve this problem, this research adopts the weighted spike-triggered average (WSTA) method. In the WSTA method, a sequential pulsed perturbation is used for stimulation. This is in contrast with the conventional impulse method, which applies an intermittent impulsive perturbation. The WSTA method can be used to analyze responses to a large number of perturbations for each sequence. In the experiment, perturbations are applied to walking subjects by rapidly accelerating and decelerating a treadmill belt, and measured data are analyzed by the WSTA and impulse methods. The PRC obtained by the WSTA method had clear and stable waveforms with a higher temporal resolution than those obtained by the impulse method. By investigation of the rhythm transition for each phase of walking using the obtained PRC, a rhythm change that extends the touch-down and mid-single support phases is found to occur. PMID:27203839

  12. Evaluation of the Phase-Dependent Rhythm Control of Human Walking Using Phase Response Curves.

    PubMed

    Funato, Tetsuro; Yamamoto, Yuki; Aoi, Shinya; Imai, Takashi; Aoyagi, Toshio; Tomita, Nozomi; Tsuchiya, Kazuo

    2016-05-01

    Humans and animals control their walking rhythms to maintain motion in a variable environment. The neural mechanism for controlling rhythm has been investigated in many studies using mechanical and electrical stimulation. However, quantitative evaluation of rhythm variation in response to perturbation at various timings has rarely been investigated. Such a characteristic of rhythm is described by the phase response curve (PRC). Dynamical simulations of human skeletal models with changing walking rhythms (phase reset) described a relation between the effective phase reset on stability and PRC, and phase reset around touch-down was shown to improve stability. A PRC of human walking was estimated by pulling the swing leg, but such perturbations hardly influenced the stance leg, so the relation between the PRC and walking events was difficult to discuss. This research thus examines human response to variations in floor velocity. Such perturbation yields another problem, in that the swing leg is indirectly (and weakly) perturbed, so the precision of PRC decreases. To solve this problem, this research adopts the weighted spike-triggered average (WSTA) method. In the WSTA method, a sequential pulsed perturbation is used for stimulation. This is in contrast with the conventional impulse method, which applies an intermittent impulsive perturbation. The WSTA method can be used to analyze responses to a large number of perturbations for each sequence. In the experiment, perturbations are applied to walking subjects by rapidly accelerating and decelerating a treadmill belt, and measured data are analyzed by the WSTA and impulse methods. The PRC obtained by the WSTA method had clear and stable waveforms with a higher temporal resolution than those obtained by the impulse method. By investigation of the rhythm transition for each phase of walking using the obtained PRC, a rhythm change that extends the touch-down and mid-single support phases is found to occur.

  13. Evaluation of the Phase-Dependent Rhythm Control of Human Walking Using Phase Response Curves.

    PubMed

    Funato, Tetsuro; Yamamoto, Yuki; Aoi, Shinya; Imai, Takashi; Aoyagi, Toshio; Tomita, Nozomi; Tsuchiya, Kazuo

    2016-05-01

    Humans and animals control their walking rhythms to maintain motion in a variable environment. The neural mechanism for controlling rhythm has been investigated in many studies using mechanical and electrical stimulation. However, quantitative evaluation of rhythm variation in response to perturbation at various timings has rarely been investigated. Such a characteristic of rhythm is described by the phase response curve (PRC). Dynamical simulations of human skeletal models with changing walking rhythms (phase reset) described a relation between the effective phase reset on stability and PRC, and phase reset around touch-down was shown to improve stability. A PRC of human walking was estimated by pulling the swing leg, but such perturbations hardly influenced the stance leg, so the relation between the PRC and walking events was difficult to discuss. This research thus examines human response to variations in floor velocity. Such perturbation yields another problem, in that the swing leg is indirectly (and weakly) perturbed, so the precision of PRC decreases. To solve this problem, this research adopts the weighted spike-triggered average (WSTA) method. In the WSTA method, a sequential pulsed perturbation is used for stimulation. This is in contrast with the conventional impulse method, which applies an intermittent impulsive perturbation. The WSTA method can be used to analyze responses to a large number of perturbations for each sequence. In the experiment, perturbations are applied to walking subjects by rapidly accelerating and decelerating a treadmill belt, and measured data are analyzed by the WSTA and impulse methods. The PRC obtained by the WSTA method had clear and stable waveforms with a higher temporal resolution than those obtained by the impulse method. By investigation of the rhythm transition for each phase of walking using the obtained PRC, a rhythm change that extends the touch-down and mid-single support phases is found to occur. PMID:27203839

  14. In search of a phase response curve for lithium chloride

    SciTech Connect

    Readey, M.A.; Groh, K.R.; Ehret, C.F.

    1987-01-01

    Male rats were free-run, and one day later were exposed to a single, punctate dose of 5 mM LiCl/kg body weight by injection at one of eight equally spaced times throughout the 24-h period. For each of the six days following injection, a separate phase response curve was derived from core-temperature chronograms. Unlike the classical response induced by chronobiotics such as dexamethasone, alpha-methyl-para-tyrosine, and theophylline, statistically significant phase shifts for lithium were observed only on the first day following injection. These induced phase changes were not permanent, but instead were transient. By the sixth day of free-run, all experimental rats had drifted to the control acrophase; i.e., by the end of the experiment, most of the treated rats again had phase and confidence arcs not significantly different from their controls. The confidence arcs of the acrophases of the individual animals on the subsequent days post injection reveal that in this experiment, lithium was transiently dyschronogenic rather than definitively chronobiotic. The results suggest that punctate rather than chronic administration of lithium, followed by strict orthochronal administration of traditional zeitgebers, would be an effective way of restoring circadian synchrony in an internally desynchronized system. 122 refs.

  15. Normal Caloric Responses during Acute Phase of Vestibular Neuritis

    PubMed Central

    Lee, Sun-Uk; Park, Seong-Ho; Kim, Hyo-Jung; Koo, Ja-Won

    2016-01-01

    Background and Purpose We report a novel finding of caloric conversion from normal responses into unilateral paresis during the acute phase of vestibular neuritis (VN). Methods We recruited 893 patients with a diagnosis of VN at Dizziness Clinic of Seoul National University Bundang Hospital from 2003 to 2014 after excluding 28 patients with isolated inferior divisional VN (n=14) and those without follow-up tests despite normal caloric responses initially (n=14). We retrospectively analyzed the neurotological findings in four (0.5%) of the patients who showed a conversion from initially normal caloric responses into unilateral paresis during the acute phase. Results In those four patients, the initial caloric tests were performed within 2 days of symptom onset, and conversion into unilateral caloric paresis was documented 1–4 days later. The clinical and laboratory findings during the initial evaluation were consistent with VN in all four patients except for normal findings in bedside head impulse tests in one of them. Conclusions Normal findings in caloric tests should be interpreted with caution during the acute phase of suspected VN. Follow-up evaluation should be considered when the findings of the initial caloric test are normal, but VN remains the most plausible diagnosis. PMID:26932259

  16. Dendritic cells from the elderly display an intrinsic defect in the production of IL-10 in response to lithium chloride.

    PubMed

    Agrawal, Sudhanshu; Gollapudi, Sastry; Gupta, Sudhir; Agrawal, Anshu

    2013-11-01

    Chronic, low grade inflammation is a characteristic of old age. Innate immune system cells such as dendritic cells (DCs) from the elderly display a pro-inflammatory phenotype associated with increased reactivity to self. Lithium is a well-established anti-inflammatory agent used in the treatment of bipolar disorders. It has also been reported to reduce inflammation in DCs. Here, we investigated whether Lithium is effective in reducing the inflammatory responses in DCs from the elderly. The effect of Lithium Chloride (LiCl) was compared on the response of TLR4 agonist, LPS and TLR2 agonist, PAM3CSK4 stimulated aged and young DCs. LiCl enhanced the production of IL-10 in LPS stimulated young DCs. However, it did not affect TNF-α and IL-6 production. In contrast, in aged DCs, LiCl reduced the secretion of TNF-α and IL-6 in LPS stimulated DCs but did not increase IL-10. LiCl had no significant effect on PAM3CSK4 responses in aged and young DCs. LiCl treated DCs also displayed differences at the level of CD4 T cell priming and polarization. LPS-stimulated young DCs reduced IFN-γ secretion and biased the Th cell response towards Th2/Treg while LiCl treated aged DCs only reduced IFN-γ secretion but did not bias the response towards Th2/Treg. In summary, our data suggests that LiCl reduces inflammation in aged and young DCs via different mechanisms. Furthermore, the effect of LiCl is different on LPS and PAM3CSK4 responses.

  17. A West Nile virus NS4B-P38G mutant strain induces cell intrinsic innate cytokine responses in human monocytic and macrophage cells

    PubMed Central

    Xie, Guorui; Luo, Huanle; Tian, Bing; Mann, Brian; Bao, Xiaoyong; McBride, Jere; Tesh, Robert; Barrett, Alan D; Wang, Tian

    2015-01-01

    Previous studies have shown that an attenuated West Nile virus (WNV) nonstructural (NS) 4B-P38G mutant induces stronger innate and adaptive immune responses than wild-type WNV in mice, which has important applications to vaccine development. To investigate the mechanism of immunogenicity, we characterized WNV NS4B-P38G mutant infection in two human cell lines--THP-1 cells and THP-1 macrophages. Although the NS4B-P38G mutant produced more viral RNA than the parental WNV NY99 in both cell types, there was no detectable infectious virus in the supernatant of either cell type. Nonetheless, the attenuated mutant boosted higher innate cytokine responses than virulent parental WNV NY99 in these cells. The NS4B-P38G mutant infection of THP-1 cells led to more diverse and robust innate cytokine responses than that seen in THP-1 macrophages, which were mediated by toll-like receptor (TLR)7 and retinoic acid-inducible gene 1(RIG-I) signaling pathways. Overall, these results suggest that a defective viral life cycle during NS4B-P38G mutant infection in human monocytic and macrophage cells leads to more potent cell intrinsic innate cytokine responses. PMID:25562791

  18. Phase response curves for models of earthquake fault dynamics

    NASA Astrophysics Data System (ADS)

    Franović, Igor; Kostić, Srdjan; Perc, Matjaž; Klinshov, Vladimir; Nekorkin, Vladimir; Kurths, Jürgen

    2016-06-01

    We systematically study effects of external perturbations on models describing earthquake fault dynamics. The latter are based on the framework of the Burridge-Knopoff spring-block system, including the cases of a simple mono-block fault, as well as the paradigmatic complex faults made up of two identical or distinct blocks. The blocks exhibit relaxation oscillations, which are representative for the stick-slip behavior typical for earthquake dynamics. Our analysis is carried out by determining the phase response curves of first and second order. For a mono-block fault, we consider the impact of a single and two successive pulse perturbations, further demonstrating how the profile of phase response curves depends on the fault parameters. For a homogeneous two-block fault, our focus is on the scenario where each of the blocks is influenced by a single pulse, whereas for heterogeneous faults, we analyze how the response of the system depends on whether the stimulus is applied to the block having a shorter or a longer oscillation period.

  19. Phase response curves for models of earthquake fault dynamics.

    PubMed

    Franović, Igor; Kostić, Srdjan; Perc, Matjaž; Klinshov, Vladimir; Nekorkin, Vladimir; Kurths, Jürgen

    2016-06-01

    We systematically study effects of external perturbations on models describing earthquake fault dynamics. The latter are based on the framework of the Burridge-Knopoff spring-block system, including the cases of a simple mono-block fault, as well as the paradigmatic complex faults made up of two identical or distinct blocks. The blocks exhibit relaxation oscillations, which are representative for the stick-slip behavior typical for earthquake dynamics. Our analysis is carried out by determining the phase response curves of first and second order. For a mono-block fault, we consider the impact of a single and two successive pulse perturbations, further demonstrating how the profile of phase response curves depends on the fault parameters. For a homogeneous two-block fault, our focus is on the scenario where each of the blocks is influenced by a single pulse, whereas for heterogeneous faults, we analyze how the response of the system depends on whether the stimulus is applied to the block having a shorter or a longer oscillation period. PMID:27368770

  20. Cephalic phase metabolic responses in normal weight adults.

    PubMed

    Bruce, D G; Storlien, L H; Furler, S M; Chisholm, D J

    1987-08-01

    The presence and physiologic importance of cephalic phase insulin release in humans remains controversial. The aim of these studies was to determine whether cephalic phase insulin release could be demonstrated in normal weight subjects and whether it would be associated with changes in blood glucose, free fatty acid, and pancreatic polypeptide levels. The studies were followed by a hyperglycemic clamp to determine whether cephalic responses would alter overall glucose disposal or glucose-stimulated insulin secretion. In all, 17 subjects were studied on two occasions with and without (control study) presentation of food stimuli. Tease-feeding alone (n = 6), or the administration of a sweet taste alone (aspartame, n = 5) failed to stimulate cephalic responses. However, the presentation of the combined stimuli (tease meals plus sweet taste, n = 7) resulted in a significant fall (P less than .005) in blood glucose levels and a variable rise in serum insulin (% insulin rise 38 +/- 15%, P less than .05) and C-peptide levels (7 +/- 6%, NS) within five minutes of the food presentation when compared with control studies, with no change seen in free fatty acid or pancreatic polypeptide levels. The blood glucose fall correlated strongly (r = .90, P less than .01) with a score of the subjective response to the food and taste.(ABSTRACT TRUNCATED AT 250 WORDS)

  1. Phase response curves for models of earthquake fault dynamics.

    PubMed

    Franović, Igor; Kostić, Srdjan; Perc, Matjaž; Klinshov, Vladimir; Nekorkin, Vladimir; Kurths, Jürgen

    2016-06-01

    We systematically study effects of external perturbations on models describing earthquake fault dynamics. The latter are based on the framework of the Burridge-Knopoff spring-block system, including the cases of a simple mono-block fault, as well as the paradigmatic complex faults made up of two identical or distinct blocks. The blocks exhibit relaxation oscillations, which are representative for the stick-slip behavior typical for earthquake dynamics. Our analysis is carried out by determining the phase response curves of first and second order. For a mono-block fault, we consider the impact of a single and two successive pulse perturbations, further demonstrating how the profile of phase response curves depends on the fault parameters. For a homogeneous two-block fault, our focus is on the scenario where each of the blocks is influenced by a single pulse, whereas for heterogeneous faults, we analyze how the response of the system depends on whether the stimulus is applied to the block having a shorter or a longer oscillation period.

  2. Collective phase response curves for heterogeneous coupled oscillators

    NASA Astrophysics Data System (ADS)

    Hannay, Kevin M.; Booth, Victoria; Forger, Daniel B.

    2015-08-01

    Phase response curves (PRCs) have become an indispensable tool in understanding the entrainment and synchronization of biological oscillators. However, biological oscillators are often found in large coupled heterogeneous systems and the variable of physiological importance is the collective rhythm resulting from an aggregation of the individual oscillations. To study this phenomena we consider phase resetting of the collective rhythm for large ensembles of globally coupled Sakaguchi-Kuramoto oscillators. Making use of Ott-Antonsen theory we derive an asymptotically valid analytic formula for the collective PRC. A result of this analysis is a characteristic scaling for the change in the amplitude and entrainment points for the collective PRC compared to the individual oscillator PRC. We support the analytical findings with numerical evidence and demonstrate the applicability of the theory to large ensembles of coupled neuronal oscillators.

  3. Collective phase response curves for heterogeneous coupled oscillators.

    PubMed

    Hannay, Kevin M; Booth, Victoria; Forger, Daniel B

    2015-08-01

    Phase response curves (PRCs) have become an indispensable tool in understanding the entrainment and synchronization of biological oscillators. However, biological oscillators are often found in large coupled heterogeneous systems and the variable of physiological importance is the collective rhythm resulting from an aggregation of the individual oscillations. To study this phenomena we consider phase resetting of the collective rhythm for large ensembles of globally coupled Sakaguchi-Kuramoto oscillators. Making use of Ott-Antonsen theory we derive an asymptotically valid analytic formula for the collective PRC. A result of this analysis is a characteristic scaling for the change in the amplitude and entrainment points for the collective PRC compared to the individual oscillator PRC. We support the analytical findings with numerical evidence and demonstrate the applicability of the theory to large ensembles of coupled neuronal oscillators.

  4. A neural mechanism of phase-locked responses to sinusoidally amplitude-modulated signals in the inferior colliculus.

    PubMed

    Kato, Takayuki; Fujita, Kazuhisa; Kashimori, Yoshiki

    2015-08-01

    The central nucleus of the inferior colliculus (ICc) is an auditory region that receives convergent inputs from a large number of lower auditory nuclei. ICc neurons phase-lock to low frequencies of sinusoidally amplitude-modulated (SAM) signals but have a different mechanism in the phase-locking from that in neurons of lower nuclei. In the mustached bat, the phase-locking ability in lower nuclei is created by the coincidence of phase-locked excitatory and inhibitory inputs that have slightly different latencies. In contrast, the phase-locking property of ICc neurons is little influenced by the blocking of inhibitory synapses. Moreover, ICc neurons exhibit different characteristics in the spike patterns and synchronicity, classified here by three types of ICc neurons, or sustained, onset, and non-onset phase-locking neurons. However it remains unclear how ICc neurons create the phase-locking ability and the different characteristics. To address this issue, we developed a model of ICc neuronal population. Using this model, we show that the phase-locking ability of ICc neurons to low SAM frequencies is created by an intrinsic membrane property of ICc neuron, limited by inhibitory ion channels. We also show that response characteristics of the three types of neurons arise from the difference in an inhibitory effect sensitive to SAM frequencies. Our model reproduces well the experimental results observed in the mustached bat. These findings provide necessary conditions of how ICc neurons can give rise to the phase-locking ability and characteristic responses to low SAM frequencies. PMID:26032987

  5. Intrinsic Viral Factors Are the Dominant Determinants of the Hepatitis C Virus Response to Interferon Alpha Treatment in Chimeric Mice

    PubMed Central

    Chen, Ran; Kobewka, Michelle; Addison, William; Lachance, Gerald; Tyrrell, D. Lorne

    2016-01-01

    Background Hepatitis C virus infection is a global health problem. New direct-acting antiviral agents have been recently approved. However, due to their high cost and some genotypes remaining difficult to treat, interferon-based therapy with pegylated interferon and ribavirin likely may remain a component of hepatitis C virus treatment for some patients. Unfortunately, pegylated interferon / ribavirin treatment achieved favorable outcomes in less than 50% of patients. Factors determining the outcome to pegylated interferon / ribavirin include both host and viral factors. It has been a major challenge to separate the host and viral factors in most in vivo systems. Aims & Methods We used two hepatitis C virus strains from patients with different interferon-sensitivities and three hepatocyte donors, each with distinct interleukin 28B and interferon lambda 4 single nucleotide polymorphisms to investigate the contributions of viral and host factors to the response of hepatitis C virus to interferon treatment in chimeric mice. Results and Conclusions We found that viral factors were the dominant factors in determining the interferon treatment outcomes in chimeric mice. Host factors, such as pre-treatment liver interferon-stimulated gene expression and single nucleotide polymorphisms near interleukin 28B and interferon lambda 4 coding regions, were less important determinants of the response to interferon in the chimeric mice than they were in patients. Our results also suggest that a complete immune system as seen in patients may be required for host factors such as single nucleotide polymorphisms near interleukin 28B / interferon lambda 4 and pre-treatment liver interferon-stimulated gene upregulation to have an effect on the interferon response. PMID:26765841

  6. Antigen Receptor-Intrinsic Non-Self: The Key to Understanding Regulatory Lymphocyte-Mediated Idiotypic Control of Adaptive Immune Responses.

    PubMed

    Lemke, Hilmar

    2016-01-01

    The clone-specific or idiotypic characters of B as well as T cell antigen receptors (BCRs/TCRs) are associated with (1) the third-complementarity-determining regions (CDR3s) that are created during V(D)J recombination (they scarcely occur in antibody light chains) and (2) BCR idiotopes created by somatic hypermutations (SHMs) during immune responses. Therefore, BCR/TCR idiotypic sites are antigen receptor-intrinsic Non-Self (AgR-iNS) portions that fulfill two tasks: serving as a crucial component of the epitope-binding paratope and serving as target sites for anti-idiotypic BCR/TCR paratopes of other anti-Non-Self clones that are contained in both normal repertoires. The antigen-induced immune response is thus directed not only toward the environmental stimulus but also against the AgR-iNS portions of the directly and further activated clones that form a subsiding idiotypic cascade. These idiotypic chain reactions form a completely integrated idiotypic control circuit among B and T cells which contains all regulatory T and B cells. However, this circuit cannot be viewed as a network of fixed interacting nodes but rather uses the genetic Self as reference. Hence, AgR-iNS offers a mechanistic understanding of regulatory lymphocyte-mediated idiotypic control of adaptive immune responses and reconciles clonal selection and idiotypic network theories hitherto believed to be incompatible. PMID:27480901

  7. Antigen Receptor-Intrinsic Non-Self: The Key to Understanding Regulatory Lymphocyte-Mediated Idiotypic Control of Adaptive Immune Responses.

    PubMed

    Lemke, Hilmar

    2016-01-01

    The clone-specific or idiotypic characters of B as well as T cell antigen receptors (BCRs/TCRs) are associated with (1) the third-complementarity-determining regions (CDR3s) that are created during V(D)J recombination (they scarcely occur in antibody light chains) and (2) BCR idiotopes created by somatic hypermutations (SHMs) during immune responses. Therefore, BCR/TCR idiotypic sites are antigen receptor-intrinsic Non-Self (AgR-iNS) portions that fulfill two tasks: serving as a crucial component of the epitope-binding paratope and serving as target sites for anti-idiotypic BCR/TCR paratopes of other anti-Non-Self clones that are contained in both normal repertoires. The antigen-induced immune response is thus directed not only toward the environmental stimulus but also against the AgR-iNS portions of the directly and further activated clones that form a subsiding idiotypic cascade. These idiotypic chain reactions form a completely integrated idiotypic control circuit among B and T cells which contains all regulatory T and B cells. However, this circuit cannot be viewed as a network of fixed interacting nodes but rather uses the genetic Self as reference. Hence, AgR-iNS offers a mechanistic understanding of regulatory lymphocyte-mediated idiotypic control of adaptive immune responses and reconciles clonal selection and idiotypic network theories hitherto believed to be incompatible.

  8. Acute phase proteins response to feed deprivation in broiler chickens.

    PubMed

    Najafi, P; Zulkifli, I; Soleimani, A F; Goh, Y M

    2016-04-01

    Feed deprivation in poultry farming imposes some degree of stress to the birds, and adversely affects their well -being. Serum levels of acute phase proteins (APP) are potential physiological indicators of stress attributed to feed deprivation. However, it has not been determined how long it takes for a measurable APP response to stressors to occur in avian species. An experiment was designed to delineate the APP and circulating levels of corticosterone responses in commercial broiler chickens to feed deprivation for 30 h. It was hypothesized that feed deprivation would elicit both APP and corticosterone (CORT) reactions within 30 h that is probably associated with stress of hunger. Twenty-one day old birds were subjected to one of 5 feed deprivation periods: 0 (ad libitum, AL), 6, 12, 18, 24, and 30 h. Upon completion of the deprivation period, blood samples were collected to determine serum CORT, ovotransferrin (OVT), α1-acid glycoprotein (AGP), and ceruloplasmin (CP) concentrations. Results showed that feed deprivation for 24 h or more caused a marked elevation in CORT (P=0.002 and P<0.0001, respectively) when compared to AL. However, increases in AGP (P=0.0005), CP (P=0.0002), and OVT (P=0.0003) were only noted following 30 h of feed deprivation. It is concluded that elicitation of AGP, CP, and OVT response may represent a more chronic stressful condition than CORT response in assessing the well-being of broiler chickens.

  9. Acute phase protein response in the capybara (Hydrochoerus hydrochaeris).

    PubMed

    Bernal, Luis; Feser, Mariane; Martínez-Subiela, Silvia; García-Martínez, Juan D; Cerón, José J; Tecles, Fernando

    2011-10-01

    We evaluated the acute phase protein response in capybaras (Hydrochoerus hydrochaeris). Three animal groups were used: 1) healthy animals (n=30), 2) a group in which experimental inflammation with turpentine was induced (n=6), and 3) a group affected with sarcoptic scabies (n=14) in which 10 animals were treated with ivermectin. Haptoglobin (Hp), acid-soluble glycoprotein (ASG) and albumin were analyzed in all animals. In those treated with turpentine, Hp reached its maximum value at 2 wk with a 2.7-fold increase, whereas ASG increased 1.75-fold and albumin decreased 0.87-fold 1 wk after the induction of inflammation. Capybaras affected with sarcoptic scabies presented increases in Hp and ASG of 4.98- and 3.18-fold, respectively, and a 0.87-fold decrease in albumin, compared with healthy animals. Haptoglobin and ASG can be considered as moderate, positive acute phase proteins in capybaras because they showed less than 10-fold increases after an inflammatory process and reached their peak concentrations 1 wk after the induction of inflammation. Conversely, albumin can be considered a negative acute phase protein in capybaras because it showed a reduction in concentration after inflammatory stimulus.

  10. Robust Entrainment of Circadian Oscillators Requires Specific Phase Response Curves

    PubMed Central

    Pfeuty, Benjamin; Thommen, Quentin; Lefranc, Marc

    2011-01-01

    The circadian clocks keeping time in many living organisms rely on self-sustained biochemical oscillations entrained by external cues, such as light, to the 24-h cycle induced by Earth's rotation. However, environmental cues are unreliable due to the variability of habitats, weather conditions, or cue-sensing mechanisms among individuals. A tempting hypothesis is that circadian clocks have evolved so as to be robust to fluctuations in the signal that entrains them. To support this hypothesis, we analyze the synchronization behavior of weakly and periodically forced oscillators in terms of their phase response curve (PRC), which measures phase changes induced by a perturbation applied at different times of the cycle. We establish a general relationship between the robustness of key entrainment properties, such as stability and oscillator phase, on the one hand, and the shape of the PRC as characterized by a specific curvature or the existence of a dead zone, on the other hand. The criteria obtained are applied to computational models of circadian clocks and account for the disparate robustness properties of various forcing schemes. Finally, the analysis of PRCs measured experimentally in several organisms strongly suggests a case of convergent evolution toward an optimal strategy for maintaining a clock that is accurate and robust to environmental fluctuations. PMID:21641300

  11. Adrenal steroids in the brain: role of the intrinsic expression of corticosteroid-binding globulin (CBG) in the stress response.

    PubMed

    Sivukhina, Elena V; Jirikowski, Gustav F

    2014-03-01

    The complex interaction between hypothalamus, pituitary and adrenal glands is a key component of the neuroendocrine stress response. The major stress hormones--glucocorticoids--have both central and peripheral effects. Among the factors regulating their availability to target tissues are levels of corticosteroid-binding globulin, as the major transport protein for glucocorticoids in systemic circulation. Our recent findings demonstrated expression of corticosteroid-binding globulin in various brain regions and in different cell populations (neurons and glial cells). We showed at the cellular level the presence of corticosteroid-binding globulin in the human hypothalamus, where it was co-localized with the classical neurohypophyseal neurohormones--vasopressin and oxytocin. For the first time we demonstrated in mouse that the same gene encodes brain and liver corticosteroid-binding globulin. The full-length sequencing of hypothalamic corticosteroid-binding globulin revealed a full homology with liver corticosteroid-binding globulin cDNA. Thus, we confirmed that corticosteroid-binding globulin mRNA is produced locally within various cerebral regions and thus not transported from blood. However, the amounts of mRNA encoding corticosteroid-binding globulin are in liver about 200 times higher than in brain. The wide distribution of corticosteroid-binding globulin, distinct from the localization of glucocorticoid receptors, observed in our comparative study in rodents, led us to propose two possibilities: (1) corticosteroid-binding globulin is made in certain neurons to deliver glucocorticoids into the cell and within the cell in the absence of cytoplasmic glucocorticoid receptors or (2) is internalized into neurons specifically to deliver glucocorticoids to classical glucocorticoid receptors. Brain corticosteroid-binding globulin may be involved in the response to changing systemic glucocorticoid levels either additionally to known nuclear and membrane corticosteroid

  12. Allyl isothiocyanate from mustard seed is effective in reducing the levels of volatile sulfur compounds responsible for intrinsic oral malodor.

    PubMed

    Tian, Minmin; Hanley, A Bryan; Dodds, Michael W J

    2013-06-01

    Oral malodor is a major social and psychological issue that affects general populations. Volatile sulfur compounds (VSCs), particularly hydrogen sulfide (H₂S) and methyl mercaptan (CH₃SH), are responsible for most oral malodor. The objectives for this study were to determine whether allyl isothiocyanate (AITC) at an organoleptically acceptable level can eliminate VSCs containing a free thiol moiety and further to elucidate the mechanism of action and reaction kinetics. The study revealed that gas chromatograph with a sulfur detector demonstrated a good linearity, high accuracy and sensitivity on analysis of VSCs. Zinc salts eliminate the headspace level of H₂S but not CH₃SH. AITC eliminates both H₂S and CH₃SH via a nucleophilic addition reaction. In addition, a chemical structure-activity relationship study revealed that the presence of unsaturated group on the side chain of the isothiocyanate accelerates the elimination of VSCs. PMID:23470258

  13. The Touch and Zap Method for In Vivo Whole-Cell Patch Recording of Intrinsic and Visual Responses of Cortical Neurons and Glial Cells

    PubMed Central

    Schramm, Adrien E.; Marinazzo, Daniele; Gener, Thomas; Graham, Lyle J.

    2014-01-01

    Whole-cell patch recording is an essential tool for quantitatively establishing the biophysics of brain function, particularly in vivo. This method is of particular interest for studying the functional roles of cortical glial cells in the intact brain, which cannot be assessed with extracellular recordings. Nevertheless, a reasonable success rate remains a challenge because of stability, recording duration and electrical quality constraints, particularly for voltage clamp, dynamic clamp or conductance measurements. To address this, we describe “Touch and Zap”, an alternative method for whole-cell patch clamp recordings, with the goal of being simpler, quicker and more gentle to brain tissue than previous approaches. Under current clamp mode with a continuous train of hyperpolarizing current pulses, seal formation is initiated immediately upon cell contact, thus the “Touch”. By maintaining the current injection, whole-cell access is spontaneously achieved within seconds from the cell-attached configuration by a self-limited membrane electroporation, or “Zap”, as seal resistance increases. We present examples of intrinsic and visual responses of neurons and putative glial cells obtained with the revised method from cat and rat cortices in vivo. Recording parameters and biophysical properties obtained with the Touch and Zap method compare favourably with those obtained with the traditional blind patch approach, demonstrating that the revised approach does not compromise the recorded cell. We find that the method is particularly well-suited for whole-cell patch recordings of cortical glial cells in vivo, targeting a wider population of this cell type than the standard method, with better access resistance. Overall, the gentler Touch and Zap method is promising for studying quantitative functional properties in the intact brain with minimal perturbation of the cell's intrinsic properties and local network. Because the Touch and Zap method is performed semi

  14. Brown and white adipose tissues: intrinsic differences in gene expression and response to cold exposure in mice.

    PubMed

    Rosell, Meritxell; Kaforou, Myrsini; Frontini, Andrea; Okolo, Anthony; Chan, Yi-Wah; Nikolopoulou, Evanthia; Millership, Steven; Fenech, Matthew E; MacIntyre, David; Turner, Jeremy O; Moore, Jonathan D; Blackburn, Edith; Gullick, William J; Cinti, Saverio; Montana, Giovanni; Parker, Malcolm G; Christian, Mark

    2014-04-15

    Brown adipocytes dissipate energy, whereas white adipocytes are an energy storage site. We explored the plasticity of different white adipose tissue depots in acquiring a brown phenotype by cold exposure. By comparing cold-induced genes in white fat to those enriched in brown compared with white fat, at thermoneutrality we defined a "brite" transcription signature. We identified the genes, pathways, and promoter regulatory motifs associated with "browning," as these represent novel targets for understanding this process. For example, neuregulin 4 was more highly expressed in brown adipose tissue and upregulated in white fat upon cold exposure, and cell studies showed that it is a neurite outgrowth-promoting adipokine, indicative of a role in increasing adipose tissue innervation in response to cold. A cell culture system that allows us to reproduce the differential properties of the discrete adipose depots was developed to study depot-specific differences at an in vitro level. The key transcriptional events underpinning white adipose tissue to brown transition are important, as they represent an attractive proposition to overcome the detrimental effects associated with metabolic disorders, including obesity and type 2 diabetes.

  15. HGFL supports mammary tumorigenesis by enhancing tumor cell intrinsic survival and influencing macrophage and T-cell responses

    PubMed Central

    Benight, Nancy M.; Wagh, Purnima K.; Zinser, Glendon M.; Peace, Belinda E.; Stuart, William D.; Vasiliauskas, Juozas; Pathrose, Peterson; Starnes, Sandra L.; Waltz, Susan E.

    2015-01-01

    The Ron receptor is overexpressed in human breast cancers and is associated with heightened metastasis and poor survival. Ron overexpression in the mammary epithelium of mice is sufficient to induce aggressive mammary tumors with a high degree of metastasis. Despite the well-documented role of Ron in breast cancer, few studies have examined the necessity of the endogenous Ron ligand, hepatocyte growth factor-like protein (HGFL) in mammary tumorigenesis. Herein, mammary tumor growth and metastasis were examined in mice overexpressing Ron in the mammary epithelium with or without HGFL. HGFL ablation decreased oncogenic Ron activation and delayed mammary tumor initiation. HGFL was important for tumor cell proliferation and survival. HGFL loss resulted in increased numbers of macrophages and T-cells within the tumor. T-cell proliferation and cytotoxicity dramatically increased in HGFL deficient mice. Biochemical analysis of HGFL proficient tumors showed increased local HGFL production, with HGFL loss decreasing β-catenin expression and NF-κB activation. Re-expression of HGFL in HGFL deficient tumor cells stimulated cell migration and invasion with coordinate activation of NF-κB and reduced apoptosis. Together, these results demonstrate critical in vivo functions for HGFL in promoting breast tumorigenesis and suggest that targeting HGFL may inhibit tumor growth and reactivate anti-tumor immune responses. PMID:25938541

  16. The effects of inhaled corticosteroids on intrinsic responsiveness and histology of airways from infant monkeys exposed to house dust mite allergen and ozone

    SciTech Connect

    Joad, Jesse P. Kott, Kayleen S.; Bric, John M.; Schelegle, Edward S.; Gershwin, Laurel J.; Plopper, Charles G.; Peake, Janice L.; Pinkerton, Kent E.

    2008-01-15

    Inhaled corticosteroids (ICS) are recommended to treat infants with asthma, some with intermittent asthma. We previously showed that exposing infant monkeys to allergen/ozone resulted in asthma-like characteristics of their airways. We evaluated the effects of ICS on histology and intrinsic responsiveness of allergen/ozone-exposed and normal infant primate airways. Infant monkeys were exposed by inhalation to (1) filtered air and saline, (2) house dust mite allergen (HDMA) + ozone and saline, (3) filtered air and ICS (budesonide) or (4) HDMA + ozone and ICS. Allergen/ozone exposures started at 1 month and ICS at 3 months of age. At 6 months of age, methacholine-induced changes in luminal area of airways in proximal and distal lung slices were determined using videomicrometry, followed by histology of the same slices. Proximal airway responsiveness was increased by allergen/ozone and by ICS. Eosinophil profiles were increased by allergen/ozone in both proximal and distal airways, an effect that was decreased by ICS in distal airways. In both allergen/ozone- and air-exposed monkeys, ICS increased the number of alveolar attachments in distal airways, decreased mucin in proximal airways and decreased epithelial volume in both airways. ICS increased smooth muscle in air-exposed animals while decreasing it in allergen/ozone-exposed animals in both airways. In proximal airways, there was a small but significant positive correlation between smooth muscle and airway responsiveness, as well as between alveolar attachments and responsiveness. ICS change morphology and function in normal airways as well as allergen/ozone-exposed airways, suggesting that they should be reserved for infants with active symptoms.

  17. Mechanisms intrinsic to 5-HT2B receptor-induced potentiation of NMDA receptor responses in frog motoneurones.

    PubMed

    Holohean, Alice M; Hackman, John C

    2004-10-01

    In the presence of NMDA receptor open-channel blockers [Mg(2+); (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine maleate (MK-801); 1-amino-3,5-dimethyladamantane (memantine)] and TTX, high concentrations (30-100 microm) of either 5-hydroxytryptamine (5-HT) or alpha-methyl-5-hydroxytryptamine (alpha-Me-5-HT) significantly potentiated NMDA-induced depolarizations of frog spinal cord motoneurones. Potentiation was blocked by LY-53,857 (10-30 microm), SB 206553 (10 microm), and SB 204741 (30 microm), but not by spiroxatrine (10 microm), WAY 100,635 (1-30 microm), ketanserin (10 microm), RS 102221 (10 microm), or RS 39604 (10-20 microm). Therefore, alpha-Me-5-HT's facilitatory effects appear to involve 5-HT(2B) receptors. These effects were G-protein dependent as they were prevented by prior treatment with guanylyl-5'-imidodiphosphate (GMP-PNP, 100 microm) and H-Arg-Pro-Lys-Pro-Gln-Gln-D-Trp-Phe-D-Trp-D-Trp-Met-NH(2) (GP antagonist 2A, 3-6 microm), but not by pertussis toxin (PTX, 3-6 ng ml(-1), 48 h preincubation). This potentiation was not reduced by protein kinase C inhibition with staurosporine (2.0 microm), U73122 (10 microm) or N-(2-aminoethyl)-5-isoquinolinesulfonamide HCl (H9) (77 microm) or by intracellular Ca(2+) depletion with thapsigargin (0.1 microm) (which inhibits Ca(2+)/ATPase). Exposure of the spinal cord to the L-type Ca(2+) channel blockers nifedipine (10 microm), KN-62 (5 microm) or gallopamil (100 microm) eliminated alpha-Me-5-HT's effects. The calmodulin antagonist N-(6-aminohexyl)-5-chloro-1-naphtalenesulfonamide (W7) (100 microm) diminished the potentiation. However, the calcium/calmodulin-dependent protein kinase II (CaM Kinase II) blocker KN-93 (10 microm) did not block the 5-HT enhancement of the NMDA responses. In summary, activation of 5-HT(2B) receptors by alpha-Me-5-HT facilitates NMDA-depolarizations of frog motoneurones via a G-protein, a rise in [Ca(2+)](i) from the entry of extracellular Ca(2+) through L-type Ca(2

  18. Performance evaluation of partial response continuous phase modulation: Discriminator detection

    NASA Astrophysics Data System (ADS)

    Trachtman, Eyal

    1989-09-01

    The principles of continuous phase modulation (CPM) are reviewed and signalling schemes based on it are discussed. The discriminator detector is widely used to detect CPM signals on band limited channels; it is a non-coherent detector which is widely used in mobile communication applications in which fading makes coherent detection difficult; it is suitable for frequency hopping systems. The detector's inferior response to that of a coherent detector can be compensated by suitable design. The performance is compared of various receivers which use the discriminator detector, using an especially written computer simulation. Receiver schemes considered included: Full response signal with integrate and dump filter; Integrate and dump filter with differential symbol detection; zero forcing linear equalization with symbol detection; Decision feedback equalization (DFE); Maximum likelihood sequence estimation; and Tomlinson filter configuration. The Tomlinson filter configuration, which has not previously been used in a CPM communication system, was compared with the other systems with respect to performance and complexity. For all CPM and detection schemes there are optimum values of h, the modulation index and there is no benefit in increasing the value of h and, therefore the bandwidth, beyond this value. Results are presented for various signal schemes, which indicate that detectability performance can be improved and bandwidth reduced by using a partial response CPM. There is a tradeoff between detectability performance and bandwidth, as a function of the baseband pulse duration. It was found that quaternary signal schemes gave better detectability performance than binary schemes, for the same bit-rates. The simulation results indicated that the Tomlinson-DFE configuration was effective for the partial response M-ary CPM channel with discriminator detection; spectral efficiency was not seriously degraded by precoding using the Tomlinson filter, and there was no

  19. Electrophysiological characterization of neurons in the dorsolateral pontine REM sleep induction zone of the rat: intrinsic membrane properties and responses to carbachol and orexins

    PubMed Central

    Brown§, Ritchie E.; Winston, Stuart; Basheer, Radhika; Thakkar, Mahesh M; McCarley, Robert W.

    2006-01-01

    Pharmacological, lesion and single-unit recording techniques in several animal species have identified a region of the pontine reticular formation (Subcoeruleus, SubC) just ventral to the locus coeruleus as critically involved in the generation of rapid-eye-movement (REM) sleep. However, the intrinsic membrane properties and responses of SubC neurons to neurotransmitters important in REM sleep control, such as acetylcholine and orexins/hypocretins, have not previously been examined in any animal species and thus were targeted in this study. We obtained whole-cell patch-clamp recordings from visually identified SubC neurons in rat brain slices in vitro. Two groups of large neurons (mean diameter 30 and 27μm) were tentatively identified as cholinergic (rostral SubC) and noradrenergic (caudal SubC) neurons. SubC reticular neurons (non-cholinergic, non-noradrenergic) showed a medium-sized depolarizing sag during hyperpolarizing current pulses and often had a rebound depolarization (low-threshold spike, LTS). During depolarizing current pulses they exhibited little adaptation and fired maximally at 30–90 Hz. Those SubC reticular neurons excited by carbachol (n=27) fired spontaneously at 6 Hz, often exhibited a moderately sized LTS, and varied widely in size (17–42 μm). Carbachol-inhibited SubC reticular neurons were medium-sized (15–25 μm) and constituted two groups. The larger group (n=22) was silent at rest and possessed a prominent LTS and associated 1–4 action potentials. The second, smaller group (n=8) had a delayed return to baseline at the offset of hyperpolarizing pulses. Orexins excited both carbachol excited and carbachol inhibited SubC reticular neurons. SubC reticular neurons had intrinsic membrane properties and responses to carbachol similar to those described for other reticular neurons but a larger number of carbachol inhibited neurons were found (> 50 %), the majority of which demonstrated a prominent LTS and may correspond to PGO-on neurons

  20. Electrophysiological characterization of neurons in the dorsolateral pontine rapid-eye-movement sleep induction zone of the rat: Intrinsic membrane properties and responses to carbachol and orexins.

    PubMed

    Brown, R E; Winston, S; Basheer, R; Thakkar, M M; McCarley, R W

    2006-12-01

    Pharmacological, lesion and single-unit recording techniques in several animal species have identified a region of the pontine reticular formation (subcoeruleus, SubC) just ventral to the locus coeruleus as critically involved in the generation of rapid-eye-movement (REM) sleep. However, the intrinsic membrane properties and responses of SubC neurons to neurotransmitters important in REM sleep control, such as acetylcholine and orexins/hypocretins, have not previously been examined in any animal species and thus were targeted in this study. We obtained whole-cell patch-clamp recordings from visually identified SubC neurons in rat brain slices in vitro. Two groups of large neurons (mean diameter 30 and 27 mum) were tentatively identified as cholinergic (rostral SubC) and noradrenergic (caudal SubC) neurons. SubC reticular neurons (non-cholinergic, non-noradrenergic) showed a medium-sized depolarizing sag during hyperpolarizing current pulses and often had a rebound depolarization (low-threshold spike, LTS). During depolarizing current pulses they exhibited little adaptation and fired maximally at 30-90 Hz. Those SubC reticular neurons excited by carbachol (n=27) fired spontaneously at 6 Hz, often exhibited a moderately sized LTS, and varied widely in size (17-42 mum). Carbachol-inhibited SubC reticular neurons were medium-sized (15-25 mum) and constituted two groups. The larger group (n=22) was silent at rest and possessed a prominent LTS and associated one to four action potentials. The second, smaller group (n=8) had a delayed return to baseline at the offset of hyperpolarizing pulses. Orexins excited both carbachol excited and carbachol inhibited SubC reticular neurons. SubC reticular neurons had intrinsic membrane properties and responses to carbachol similar to those described for other reticular neurons but a larger number of carbachol inhibited neurons were found (>50%), the majority of which demonstrated a prominent LTS and may correspond to pontine

  1. Seismic Safety Margins Research Program (Phase I). Project IV. Structural building response; Structural Building Response Review

    SciTech Connect

    Healey, J.J.; Wu, S.T.; Murga, M.

    1980-02-01

    As part of the Phase I effort of the Seismic Safety Margins Research Program (SSMRP) being performed by the University of California Lawrence Livermore Laboratory for the US Nuclear Regulatory Commission, the basic objective of Subtask IV.1 (Structural Building Response Review) is to review and summarize current methods and data pertaining to seismic response calculations particularly as they relate to the objectives of the SSMRP. This material forms one component in the development of the overall computational methodology involving state of the art computations including explicit consideration of uncertainty and aimed at ultimately deriving estimates of the probability of radioactive releases due to seismic effects on nuclear power plant facilities.

  2. Geometric intrinsic symmetries

    SciTech Connect

    Gozdz, A. Szulerecka, A.; Pedrak, A.

    2013-08-15

    The problem of geometric symmetries in the intrinsic frame of a many-body system (nucleus) is considered. An importance of symmetrization group notion is discussed. Ageneral structure of the intrinsic symmetry group structure is determined.

  3. Motexafin-Gadolinium and Involved Field Radiation Therapy for Intrinsic Pontine Glioma of Childhood: A Children's Oncology Group Phase 2 Study

    SciTech Connect

    Bradley, Kristin A.; Zhou Tianni; McNall-Knapp, Rene Y.; Jakacki, Regina I.; Pollack, Ian F.

    2013-01-01

    Purpose: To evaluate the effects on 1-year event-free survival (EFS) and overall survival (OS) of combining motexafin and gadolinium (MGd), a potent radiosensitizer, with daily fractionated radiation therapy in children with newly diagnosed intrinsic pontine gliomas. Methods and Materials: Patients with newly diagnosed intrinsic pontine glioma were treated with MGd daily for 5 consecutive days each week, for a total of 30 doses. Patients received a 5- to 10-min intravenous bolus of MGd, 4.4 mg/kg/day, given 2 to 5 h prior to standard dose irradiation. Radiation therapy was administered at a daily dose of 1.8 Gy for 30 treatments over 6 weeks. The total dose was 54 Gy. Results: Sixty eligible children received MGd daily, concurrent with 6 weeks of radiation therapy. The estimated 1-year EFS was 18% {+-} 5%, and the estimated 1-year OS was 53% {+-} 6.5%. The most common grade 3 to 4 toxicities were lymphopenia, transient elevation of liver transaminases, and hypertension. Conclusions: Compared to historical controls, the addition of MGd to a standard 6-week course of radiation did not improve the survival of pediatric patients with newly diagnosed intrinsic pontine gliomas.

  4. Detecting and identifying two-dimensional symmetry-protected topological, symmetry-breaking, and intrinsic topological phases with modular matrices via tensor-network methods

    NASA Astrophysics Data System (ADS)

    Huang, Ching-Yu; Wei, Tzu-Chieh

    2016-04-01

    Symmetry-protected topological (SPT) phases exhibit nontrivial order if symmetry is respected but are adiabatically connected to the trivial product phase if symmetry is not respected. However, unlike the symmetry-breaking phase, there is no local order parameter for SPT phases. Here we employ a tensor-network method to compute the topological invariants characterized by the simulated modular S and T matrices to study transitions in a few families of two-dimensional (2D) wave functions which are ZN (N =2 and3 ) symmetric. We find that in addition to the topologically ordered phases, the modular matrices can be used to identify nontrivial SPT phases and detect transitions between different SPT phases as well as between symmetric and symmetry-breaking phases. Therefore modular matrices can be used to characterize various types of gapped phases in a unifying way.

  5. Shapiro Step Response of Intrinsic Josephson Junctions of (Bi1-xPbx)2Sr2CaCu2Oy at Elevated Temperatures

    NASA Astrophysics Data System (ADS)

    Oya, G.; Miyasaka, T.; Kitamura, M.; Irie, A.

    We have studied the response of stacks of intrinsic Josephson junctions (IJJs) of (Bi1-xPbx)2Sr2CaCu2Oy (x = 0.15) to injection of microwave of frequencies frf of 2-20 GHz at 4.2 K and higher temperatures. Clear constant voltage steps, which are considered Shapiro steps, are successfully observed on the current-voltage characteristic of an IJJ with a resistivity of Josephson-vortex flow Rfl in any stack under the injection of microwave. The step of the eighth order, which is the highest in this study, is observed from the largest IJJ under injection of microwave of 10 GHz at 4.2 K. But, as the temperature increases, the number of steps decreases, and finally the steps disappear at ∼45 K due to large self-heating. In this IJJ a low Rfl plays an important role in appearance of the steps of the high order. The typical behavior of the steps at 4.2 K is well reproduced by numerical simulations on that of Shapiro steps of a JJ with the shunt resistivity equal to Rfl at the temperature.

  6. Intrinsic differences in the initiation of B cell receptor signaling favor responses of human IgG(+) memory B cells over IgM(+) naive B cells.

    PubMed

    Davey, Angel M; Pierce, Susan K

    2012-04-01

    The acquisition of long-lived memory B cells (MBCs) is critical for the defense against many infectious diseases. Despite their importance, little is known about how Ags trigger human MBCs, even though our understanding of the molecular basis of Ag activation of B cells in model systems has advanced considerably. In this study, we use quantitative, high-resolution, live-cell imaging at the single-cell and single-molecule levels to describe the earliest Ag-driven events in human isotype-switched, IgG-expressing MBCs and compare them with those in IgM-expressing naive B cells. We show that human MBCs are more robust than naive B cells at each step in the initiation of BCR signaling, including interrogation of Ag-containing membranes, formation of submicroscopic BCR oligomers, and recruitment and activation of signaling-associated kinases. Despite their robust response to Ag, MBCs remain highly sensitive to FcγRIIB-mediated inhibition. We also demonstrate that in the absence of Ag, a portion of MBC receptors spontaneously oligomerized, and phosphorylated kinases accumulated at the membrane and speculate that heightened constitutive signaling may play a role in maintaining MBC longevity. Using high-resolution imaging, we have provided a description of the earliest events in the Ag activation of MBCs and evidence for acquired cell-intrinsic differences in the initiation of BCR signaling in human naive and MBCs.

  7. Ecotoxicological evaluation of low-concentration bisphenol A exposure on the soil nematode Caenorhabditis elegans and intrinsic mechanisms of stress response in vivo.

    PubMed

    Zhou, Dong; Yang, Jie; Li, Hui; Lu, Qiang; Liu, Yong-di; Lin, Kuang-Fei

    2016-08-01

    As a representative species of nematodes, Caenorhabditis elegans is an attractive animal model for evaluating ecotoxicological effects and intrinsic mechanisms of the stress response in vivo. To acquire a better knowledge of environmental effects of bisphenol A (BPA), ecotoxicological evaluations were conducted using C. elegans on the physiological (growth, locomotion behaviors, and reproduction), biochemical (lipofuscin accumulation, reactive oxygen species production, and cell apoptosis), and molecular (stress-related gene expression) responses. Nematodes were exposed to BPA (0.001-10 µM) in 2 assay systems (L4 larvae for 24 h and L1 larvae for 72 h). Exposure to BPA could significantly (p < 0.05) alter body length, locomotion behaviors, brood size, cell apoptosis, and selected stress-related gene expression. At the physiological level, BPA exerted adverse effects on nematodes at the microgram per liter level in both assay systems, with head thrashes as the most sensitive endpoint. At the biochemical level, apoptosis degree showed increases at concentrations above 0.1 µM in both assay systems. At the molecular level, BPA induced increases in selected stress-related gene expression, even at the lowest tested concentration. In addition, BPA-induced cell apoptosis was suggested as a potential mode of action, resulting in adverse physiological effects. Therefore, BPA exposure was speculated to impose developmental, reproductive, and neurobehavioral toxicities on C. elegans and caused variations of stress-related gene expression. Environ Toxicol Chem 2016;35:2041-2047. © 2016 SETAC.

  8. B Cell-Intrinsic Expression of the HuR RNA-Binding Protein Is Required for the T Cell-Dependent Immune Response In Vivo.

    PubMed

    DeMicco, Amy; Naradikian, Martin S; Sindhava, Vishal J; Yoon, Je-Hyun; Gorospe, Myriam; Wertheim, Gerald B; Cancro, Michael P; Bassing, Craig H

    2015-10-01

    The HuR RNA-binding protein posttranscriptionally controls expression of genes involved in cellular survival, proliferation, and differentiation. To determine roles of HuR in B cell development and function, we analyzed mice with B lineage-specific deletion of the HuR gene. These HuRΔ/Δ mice have reduced numbers of immature bone marrow and mature splenic B cells, with only the former rescued by p53 inactivation, indicating that HuR supports B lineage cells through developmental stage-specific mechanisms. Upon in vitro activation, HuRΔ/Δ B cells have a mild proliferation defect and impaired ability to produce mRNAs that encode IgH chains of secreted Abs, but no deficiencies in survival, isotype switching, or expression of germinal center (GC) markers. In contrast, HuRΔ/Δ mice have minimal serum titers of all Ab isotypes, decreased numbers of GC and plasma B cells, and few peritoneal B-1 B cells. Moreover, HuRΔ/Δ mice have severely decreased GCs, T follicular helper cells, and high-affinity Abs after immunization with a T cell-dependent Ag. This failure of HuRΔ/Δ mice to mount a T cell-dependent Ab response contrasts with the ability of HuRΔ/Δ B cells to become GC-like in vitro, indicating that HuR is essential for aspects of B cell activation unique to the in vivo environment. Consistent with this notion, we find in vitro stimulated HuRΔ/Δ B cells exhibit modestly reduced surface expression of costimulatory molecules whose expression is similarly decreased in humans with common variable immunodeficiency. HuRΔ/Δ mice provide a model to identify B cell-intrinsic factors that promote T cell-dependent immune responses in vivo.

  9. B Cell-Intrinsic Expression of the HuR RNA-Binding Protein Is Required for the T Cell-Dependent Immune Response In Vivo.

    PubMed

    DeMicco, Amy; Naradikian, Martin S; Sindhava, Vishal J; Yoon, Je-Hyun; Gorospe, Myriam; Wertheim, Gerald B; Cancro, Michael P; Bassing, Craig H

    2015-10-01

    The HuR RNA-binding protein posttranscriptionally controls expression of genes involved in cellular survival, proliferation, and differentiation. To determine roles of HuR in B cell development and function, we analyzed mice with B lineage-specific deletion of the HuR gene. These HuRΔ/Δ mice have reduced numbers of immature bone marrow and mature splenic B cells, with only the former rescued by p53 inactivation, indicating that HuR supports B lineage cells through developmental stage-specific mechanisms. Upon in vitro activation, HuRΔ/Δ B cells have a mild proliferation defect and impaired ability to produce mRNAs that encode IgH chains of secreted Abs, but no deficiencies in survival, isotype switching, or expression of germinal center (GC) markers. In contrast, HuRΔ/Δ mice have minimal serum titers of all Ab isotypes, decreased numbers of GC and plasma B cells, and few peritoneal B-1 B cells. Moreover, HuRΔ/Δ mice have severely decreased GCs, T follicular helper cells, and high-affinity Abs after immunization with a T cell-dependent Ag. This failure of HuRΔ/Δ mice to mount a T cell-dependent Ab response contrasts with the ability of HuRΔ/Δ B cells to become GC-like in vitro, indicating that HuR is essential for aspects of B cell activation unique to the in vivo environment. Consistent with this notion, we find in vitro stimulated HuRΔ/Δ B cells exhibit modestly reduced surface expression of costimulatory molecules whose expression is similarly decreased in humans with common variable immunodeficiency. HuRΔ/Δ mice provide a model to identify B cell-intrinsic factors that promote T cell-dependent immune responses in vivo. PMID:26320247

  10. Rhodopsin and Melanopsin Contributions to the Early Redilation Phase of the Post-Illumination Pupil Response (PIPR)

    PubMed Central

    Adhikari, Prakash; Feigl, Beatrix; Zele, Andrew J.

    2016-01-01

    Melanopsin expressing intrinsically photosensitive Retinal Ganglion Cells (ipRGCs) entirely control the post-illumination pupil response (PIPR) from 6 s post-stimulus to the plateau during redilation after light offset. However, the photoreceptor contributions to the early redilation phase of the PIPR (< 6 s post-stimulus) have not been reported. Here, we evaluated the photoreceptor contributions to the early phase PIPR (0.6 s to 5.0 s) by measuring the spectral sensitivity of the criterion PIPR amplitude in response to 1 s light pulses at five narrowband stimulus wavelengths (409, 464, 508, 531 and 592 nm). The retinal irradiance producing a criterion PIPR was normalised to the peak and fitted by either a single photopigment nomogram or the combined melanopsin and rhodopsin spectral nomograms with the +L+M cone photopic luminous efficiency (Vλ) function. We show that the PIPR spectral sensitivity at times ≥ 1.7 s after light offset is best described by the melanopsin nomogram. At times < 1.7 s, the peak PIPR sensitivity shifts to longer wavelengths (range: 482 to 498 nm) and is best described by the combined photoreceptor nomogram, with major contributions from melanopsin and rhodopsin. This first report of melanopsin and rhodopsin contributions to the early phase PIPR is in line with the electrophysiological findings of ipRGC and rod signalling after the cessation of light stimuli and provides a cut-off time for isolating photoreceptor specific function in healthy and diseased eyes. PMID:27548480

  11. Self-biased magnetoelectric response in three-phase laminates

    NASA Astrophysics Data System (ADS)

    Yang, Su-Chul; Park, Chee-Sung; Cho, Kyung-Hoon; Priya, Shashank

    2010-11-01

    This study reports the experimental observation and analysis of self-biased magnetoelectric (ME) effect in three-phase laminates. The 2-2 L-T mode laminates were fabricated by attaching nickel (Ni) plates and ME particulate composite plates having 3-0 connectivity with 0.948Na0.5K0.5NbO3-0.052LiSbO3 (NKNLS) matrix and Ni0.8Zn0.2Fe2O4 (NZF) dispersant. The presence of two types of ferromagnetic materials, Ni and NZF, results in built-in magnetic bias due to difference in their magnetic susceptibilities and coercivity. This built-in bias (Hbias) provides finite ME effect at zero applied magnetic dc field. The ME response of bending mode trilayer laminate NKNLS-NZF/Ni/NKNLS-NZF in off-resonance and on-resonance conditions was shown to be mathematical combination of the trilayers with configuration NKNLS-NZF/Ni/NKNLS-NZF and NKNLS/Ni/NKNLS representing contributions from magnetic interaction and bending strain.

  12. Identification of S-phase DNA damage-response targets in fission yeast reveals conservation of damage-response networks.

    PubMed

    Willis, Nicholas A; Zhou, Chunshui; Elia, Andrew E H; Murray, Johanne M; Carr, Antony M; Elledge, Stephen J; Rhind, Nicholas

    2016-06-28

    The cellular response to DNA damage during S-phase regulates a complicated network of processes, including cell-cycle progression, gene expression, DNA replication kinetics, and DNA repair. In fission yeast, this S-phase DNA damage response (DDR) is coordinated by two protein kinases: Rad3, the ortholog of mammalian ATR, and Cds1, the ortholog of mammalian Chk2. Although several critical downstream targets of Rad3 and Cds1 have been identified, most of their presumed targets are unknown, including the targets responsible for regulating replication kinetics and coordinating replication and repair. To characterize targets of the S-phase DDR, we identified proteins phosphorylated in response to methyl methanesulfonate (MMS)-induced S-phase DNA damage in wild-type, rad3∆, and cds1∆ cells by proteome-wide mass spectrometry. We found a broad range of S-phase-specific DDR targets involved in gene expression, stress response, regulation of mitosis and cytokinesis, and DNA replication and repair. These targets are highly enriched for proteins required for viability in response to MMS, indicating their biological significance. Furthermore, the regulation of these proteins is similar in fission and budding yeast, across 300 My of evolution, demonstrating a deep conservation of S-phase DDR targets and suggesting that these targets may be critical for maintaining genome stability in response to S-phase DNA damage across eukaryotes.

  13. Response of two-phase droplets to intense electromagnetic radiation

    NASA Technical Reports Server (NTRS)

    Spann, James F.; Maloney, Daniel J.; Lawson, William F.; Casleton, Kent H.

    1993-01-01

    The behavior of two-phase droplets subjected to high intensity radiation pulses is studied. Droplets are highly absorbing solids in weakly absorbing liquid medium. The objective of the study was to define heating thresholds required for causing explosive boiling and secondary atomization of the fuel droplet. The results point to mechanisms for energy storage and transport in two-phase systems.

  14. Intrinsically irreversible heat engine

    DOEpatents

    Wheatley, John C.; Swift, Gregory W.; Migliori, Albert

    1984-01-01

    A class of heat engines based on an intrinsically irreversible heat transfer process is disclosed. In a typical embodiment the engine comprises a compressible fluid that is cyclically compressed and expanded while at the same time being driven in reciprocal motion by a positive displacement drive means. A second thermodynamic medium is maintained in imperfect thermal contact with the fluid and bears a broken thermodynamic symmetry with respect to the fluid. the second thermodynamic medium is a structure adapted to have a low fluid flow impedance with respect to the compressible fluid, and which is further adapted to be in only moderate thermal contact with the fluid. In operation, thermal energy is pumped along the second medium due to a phase lag between the cyclical heating and cooling of the fluid and the resulting heat conduction between the fluid and the medium. In a preferred embodiment the engine comprises an acoustical drive and a housing containing a gas which is driven at a resonant frequency so as to be maintained in a standing wave. Operation of the engine at acoustic frequencies improves the power density and coefficient of performance. The second thermodynamic medium can be coupled to suitable heat exchangers to utilize the engine as a simple refrigeration device having no mechanical moving parts. Alternatively, the engine is reversible in function so as to be utilizable as a prime mover by coupling it to suitable sources and sinks of heat.

  15. Intrinsically irreversible heat engine

    DOEpatents

    Wheatley, J.C.; Swift, G.W.; Migliori, A.

    1984-12-25

    A class of heat engines based on an intrinsically irreversible heat transfer process is disclosed. In a typical embodiment the engine comprises a compressible fluid that is cyclically compressed and expanded while at the same time being driven in reciprocal motion by a positive displacement drive means. A second thermodynamic medium is maintained in imperfect thermal contact with the fluid and bears a broken thermodynamic symmetry with respect to the fluid. The second thermodynamic medium is a structure adapted to have a low fluid flow impedance with respect to the compressible fluid, and which is further adapted to be in only moderate thermal contact with the fluid. In operation, thermal energy is pumped along the second medium due to a phase lag between the cyclical heating and cooling of the fluid and the resulting heat conduction between the fluid and the medium. In a preferred embodiment the engine comprises an acoustical drive and a housing containing a gas which is driven at a resonant frequency so as to be maintained in a standing wave. Operation of the engine at acoustic frequencies improves the power density and coefficient of performance. The second thermodynamic medium can be coupled to suitable heat exchangers to utilize the engine as a simple refrigeration device having no mechanical moving parts. Alternatively, the engine is reversible in function so as to be utilizable as a prime mover by coupling it to suitable sources and sinks of heat. 11 figs.

  16. Intrinsically irreversible heat engine

    DOEpatents

    Wheatley, J.C.; Swift, G.W.; Migliori, A.

    1984-01-01

    A class of heat engines based on an intrinsically irreversible heat transfer process is disclosed. In a typical embodiment the engine comprises a compressible fluid that is cyclically compressed and expanded while at the same time being driven in reciprocal motion by a positive displacement drive means. A second thermodynamic medium is maintained in imperfect thermal contact with the fluid and bears a broken thermodynamic symmetry with respect to the fluid. The second thermodynamic medium is a structure adapted to have a low fluid flow impedance with respect to the compressible fluid, and which is further adapted to be in only moderate thermal contact with the fluid. In operation, thermal energy is pumped along the second medium due to a phase lag between the cyclical heating and cooling of the fluid and the resulting heat conduction between the fluid and the medium. In a preferred embodiment the engine comprises an acoustical drive and a housing containing a gas which is driven at a resonant frequency so as to be maintained in a standing wave. Operation of the engine at acoustic frequencies improves the power density and coefficient of performance. The second thermodynamic medium can be coupled to suitable heat exchangers to utilize the engine as a simple refrigeration device having no mechanical moving parts. Alternatively, the engine is reversible in function so as to be utilizable as a prime mover by coupling it to suitable sources and sinks of heat.

  17. Time-delay spectrometry measurement of magnitude and phase of hydrophone response.

    PubMed

    Wear, Keith A; Gammell, Paul M; Maruvada, Subha; Liu, Yunbo; Harris, Gerald R

    2011-11-01

    A method based on time-delay spectrometry (TDS) was developed for measuring both magnitude and phase response of a hydrophone. The method was tested on several types of hydrophones used in medical ultrasound exposimetry over the range from 5 to 18 MHz. These included polyvinylidene fluoride (PVDF) spot-poled membrane, needle, and capsule designs. One needle hydrophone was designed for high-intensity focused ultrasound (HIFU) applications. The average reproducibility (after repositioning the hydrophone) of the phase measurement was 2.4°. The minimum-phase model, which implies that the phase response is equal to the inverse Hilbert transform of the natural logarithm of the magnitude response, was tested with TDS hydrophone data. Direct TDS-based measurements of hydrophone phase responses agreed well with calculations based on the minimum-phase model, with rms differences of 1.76° (PVDF spot-poled membrane hydrophone), 3.10° (PVDF capsule hydrophone), 3.43° (PVDF needle hydrophone), and 3.36° (ceramic needle hydrophone) over the range from 5 to 18 MHz. Therefore, phase responses for several types of hydrophones may be inferred from measurements of their magnitude responses. Calculation of phase response based on magnitude response using the minimumphase model is a relatively simple and practical alternative to direct measurement of phase. PMID:22083766

  18. Intrinsic Analysis Training Manual.

    ERIC Educational Resources Information Center

    Gow, Doris T.

    This manual is for the training of linking agents between Education R&D and schools and for training teachers in the process of intrinsic analysis of curriculum materials. Intrinsic analysis means analysis of the instruction or process through examination of the materials, or artifacts, including teacher and student materials, developer's…

  19. The dynamic response of high pressure phase of Si using phase contrast imaging and X-ray diffraction

    NASA Astrophysics Data System (ADS)

    Lee, H. J.; Galtier, E.; Xing, Z.; Gleason, A.; Granados, E.; Tavella, F.; Schropp, A.; Seiboth, F.; Schroer, C.; Higginbotham, A.; Brown, S.; Arnold, B.; Curiel, R.; Peterswright, D.; Fry, A.; Nagler, B.

    2015-11-01

    Static compression studies have revealed that crystalline silicon undergoes phase transitions from a cubic diamond structure to a variety of phases including body-centered tetragonal phase, an orthorhombic phase, and a hexagonal primitive phase. However, the dynamic response of silicon at high pressure is not well understood. Phase contrast imaging has proven to be a powerful tool for probing density changes caused by the shock propagation into a material. With respect to the elastic and plastic compression, we image shock waves in Si with high spatial resolution using the LCLS X-ray free electron laser and Matter in Extreme Conditions instrument. In this study, the long pulse optical laser with pseudoflat top shape creates high pressures up to 60 GPa. We also measure the crystal structure by observing the X-ray diffraction orthogonal to the shock propagation direction over a range of pressure. In this talk, we will present the capability of simultaneously performing phase contrast imaging and in situ X-ray diffraction during shock loading and will discuss the dynamic response of Si in high pressure phases

  20. Unraveling the origins of electromechanical response in mixed-phase Bismuth Ferrite

    SciTech Connect

    Vasudevan, Rama K; Okatan, M. B.; Liu, Y. Y.; Jesse, Stephen; Yang, J.-C.; Liang, W. -I.; Chu, Ying-Hao; Li, J. Y.; Kalinin, Sergei V; Valanoor, Nagarajan V

    2013-01-01

    The origin of giant electromechanical response in a mixed-phase rhombohedral-tetragonal BiFeO3 thin film is probed using sub-coercive scanning probe microscopy based multiple-harmonic measurements. Significant contributions to the strain arise from a second-order harmonic response localized at the phase boundaries. Strain and dissipation data, backed by thermodynamic calculations suggest that the source of the enhanced electromechanical response is the motion of phase boundaries. These findings elucidate the key role of labile phase boundaries, both natural and artificial, in achieving thin films with giant electromechanical properties.

  1. Characterization of Recombinant Human Cytomegaloviruses Encoding IE1 Mutants L174P and 1-382 Reveals that Viral Targeting of PML Bodies Perturbs both Intrinsic and Innate Immune Responses

    PubMed Central

    Scherer, Myriam; Otto, Victoria; Stump, Joachim D.; Klingl, Stefan; Müller, Regina; Reuter, Nina; Muller, Yves A.; Sticht, Heinrich

    2015-01-01

    early protein IE1 binds to PML via a central globular domain (IE1CORE), and we have shown previously that this is sufficient to antagonize intrinsic immunity. Here, we demonstrate that modification of PML by IE1CORE not only abrogates intrinsic defense mechanisms but also attenuates the interferon response during infection. Our data show that PML plays a novel coregulatory role in type I as well as type II interferon-induced gene expression, which is antagonized by IE1CORE. Importantly, our finding supports the view that targeting of PML-NBs by viral regulatory proteins has evolved as a strategy to inhibit both intrinsic and innate immune defense mechanisms. PMID:26559840

  2. Experimental parameters affecting hypercoulometric response in gas-phase coulometry.

    PubMed

    Ciccioli, P; Hayes, J M

    1985-01-01

    The response of an electron-capture detector designed for coulometric response was examined as a function of solute, pulse interval, carrier-gas type, solute amount, carrier-gas flow rate, and chromatographic-peak profile. For CCl3F, it was shown that the average numbers of electrons absorbed per molecule ranged from 1.0 to 4.1, varying primarily with pulse interval but also displaying a complex dependence on sample amount. Comparison of these results with theoretical expectations leads to the conclusion that a 1:1 "coulometric response" may not be observed under certain operating conditions. Because the specific conditions required depend on many variables, including, to some extent, sample amount, true coulometric operation of an electron-capture detector is difficult to establish and maintain. Effects which may contribute to the production of hypercoulometric response are critically discussed.

  3. THE ACUTE PHASE RESPONSE INDUCED BY BRONCHOSCOPY WITH LAVAGE

    EPA Science Inventory

    Bronchoscopy has been used to evaluate the inflammatory responses in vitro and in vivo. The procedure may affect acute inflammation in the lower respiratory tract. We reviewed consecutive bronchoscopies done in normal healthy non-smokers between April, 1998 and April, 2004. The...

  4. Quantitative model of the phase behavior of recombinant pH-responsive elastin-like polypeptides.

    PubMed

    Mackay, J Andrew; Callahan, Daniel J; Fitzgerald, Kelly N; Chilkoti, Ashutosh

    2010-11-01

    Quantitative models are required to engineer biomaterials with environmentally responsive properties. With this goal in mind, we developed a model that describes the pH-dependent phase behavior of a class of stimulus responsive elastin-like polypeptides (ELPs) that undergo reversible phase separation in response to their solution environment. Under isothermal conditions, charged ELPs can undergo phase separation when their charge is neutralized. Optimization of this behavior has been challenging because the pH at which they phase separate, pHt, depends on their composition, molecular weight, concentration, and temperature. To address this problem, we developed a quantitative model to describe the phase behavior of charged ELPs that uses the Henderson-Hasselbalch relationship to describe the effect of side-chain ionization on the phase-transition temperature of an ELP. The model was validated with pH-responsive ELPs that contained either acidic (Glu) or basic (His) residues. The phase separation of both ELPs fit this model across a range of pH. These results have important implications for applications of pH-responsive ELPs because they provide a quantitative model for the rational design of pH-responsive polypeptides whose transition can be triggered at a specified pH.

  5. SUMO Ligase Protein Inhibitor of Activated STAT1 (PIAS1) Is a Constituent Promyelocytic Leukemia Nuclear Body Protein That Contributes to the Intrinsic Antiviral Immune Response to Herpes Simplex Virus 1

    PubMed Central

    Brown, James R.; Conn, Kristen L.; Wasson, Peter; Charman, Matthew; Tong, Lily; Grant, Kyle; McFarlane, Steven

    2016-01-01

    ABSTRACT Aspects of intrinsic antiviral immunity are mediated by promyelocytic leukemia nuclear body (PML-NB) constituent proteins. During herpesvirus infection, these antiviral proteins are independently recruited to nuclear domains that contain infecting viral genomes to cooperatively promote viral genome silencing. Central to the execution of this particular antiviral response is the small ubiquitin-like modifier (SUMO) signaling pathway. However, the participating SUMOylation enzymes are not fully characterized. We identify the SUMO ligase protein inhibitor of activated STAT1 (PIAS1) as a constituent PML-NB protein. We show that PIAS1 localizes at PML-NBs in a SUMO interaction motif (SIM)-dependent manner that requires SUMOylated or SUMOylation-competent PML. Following infection with herpes simplex virus 1 (HSV-1), PIAS1 is recruited to nuclear sites associated with viral genome entry in a SIM-dependent manner, consistent with the SIM-dependent recruitment mechanisms of other well-characterized PML-NB proteins. In contrast to that of Daxx and Sp100, however, the recruitment of PIAS1 is enhanced by PML. PIAS1 promotes the stable accumulation of SUMO1 at nuclear sites associated with HSV-1 genome entry, whereas the accumulation of other evaluated PML-NB proteins occurs independently of PIAS1. We show that PIAS1 cooperatively contributes to HSV-1 restriction through mechanisms that are additive to those of PML and cooperative with those of PIAS4. The antiviral mechanisms of PIAS1 are counteracted by ICP0, the HSV-1 SUMO-targeted ubiquitin ligase, which disrupts the recruitment of PIAS1 to nuclear domains that contain infecting HSV-1 genomes through mechanisms that do not directly result in PIAS1 degradation. IMPORTANCE Adaptive, innate, and intrinsic immunity cooperatively and efficiently restrict the propagation of viral pathogens. Intrinsic immunity mediated by constitutively expressed cellular proteins represents the first line of intracellular defense against

  6. Atomic-Scale Determination of Active Facets on the MoVTeNb Oxide M1 Phase and Their Intrinsic Catalytic Activity for Ethane Oxidative Dehydrogenation.

    PubMed

    Melzer, Daniel; Xu, Pinghong; Hartmann, Daniela; Zhu, Yuanyuan; Browning, Nigel D; Sanchez-Sanchez, Maricruz; Lercher, Johannes A

    2016-07-25

    Aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) has been used to image the basal {001} plane of the catalytically relevant M1 phase in MoVTeNb complex oxides. Facets {010}, {120}, and {210} are identified as the most frequent lateral termination planes of the crystals. Combination of STEM with He ion microscopy (HIM) images, Rietveld analysis, and kinetic tests reveals that the activation of ethane is correlated to the availability of facets {001}, {120}, and {210} at the surface of M1 crystals. The lateral facets {120} and {210} expose crystalline positions related to the typical active centers described for propane oxidation. Conversely, the low activity of the facet {010} is attributed to its configuration, consisting of only stable M6 O21 units connected by a single octahedron. Thus, we quantitatively demonstrated that differences in catalytic activity among M1 samples of equal chemical composition depend primarily on the morphology of the particles, which determines the predominant terminating facets. PMID:26990594

  7. A pilot study of phase-evoked acoustic responses from the ears of human subjects

    NASA Astrophysics Data System (ADS)

    Christensen, Anders T.; Dewey, James; Dhar, Sumitrajit; Ordoñez, Rodrigo; Hammershøi, Dorte

    2015-12-01

    Otoacoustic emissions (OAEs) evoked by pure tones lock onto the phase of the stimulus at the place of their generation in the cochlea. The effects of phase transitions in a pure tone stimulus on OAEs have not been investigated. By combining responses to pure tones with smooth phase transitions, phase-evoked residual responses (PERRs) were extracted from nine normal-hearing subjects. Five of them had PERRs in at least 18 of 36 parameter conditions expected to yield a response. PERRs do not have a straightforward dependence on stimulus parameters, but their general prevalence suggests a temporary decoupling between stimulus and OAE phase - between 5 and 10 ms. Since the stimulus is narrow in the frequency domain, the PERR may reflect the dynamic behavior of localized regions of OAE generators.

  8. The frequency response of phased-array antennas

    NASA Astrophysics Data System (ADS)

    Brock, B. C.

    1989-02-01

    The phased-array antenna will be examined from the point of view of effects caused by changes in frequency. Both simple linear arrays and the more complex conformal array are examined. For the conformal array, a comparison between a corporate-feed structure and a row series-feed structure is included. There are two primary effects which will be discussed: beam-pointing errors and distortion of large bandwidth signals. A formula for estimating the operating or tunable array bandwidth for narrow-bandwidth signals is derived. An expression for the wide-bandwidth-signal transfer function is also obtained and examined. It will be shown that the transfer function depends both on the array scan angle and the position within the mainbeam.

  9. The frequency response of phased-array antennas

    SciTech Connect

    Brock, B.C.

    1989-02-01

    The phased-array antenna will be examined from the point of view of effects caused by changes in frequency. Both simple linear arrays and the more complex conformal array are examined. For the conformal array, a comparison between a corporate-feed structure and a row series-feed structure is included. There are two primary effects which will be discussed: beam-pointing errors and distortion of large bandwidth signals. A formula for estimating the operating or tunable array bandwidth for narrow-bandwidth signals is derived. An expression for the wide-bandwidth-signal transfer function is also obtained and examined. It will be shown that the transfer function depends both on the array scan angle and the position within the mainbeam. 25 figs.

  10. An ATM-independent S-phase checkpoint response involves CHK1 pathway

    NASA Technical Reports Server (NTRS)

    Zhou, Xiang-Yang; Wang, Xiang; Hu, Baocheng; Guan, Jun; Iliakis, George; Wang, Ya

    2002-01-01

    After exposure to genotoxic stress, proliferating cells actively slow down the DNA replication through a S-phase checkpoint to provide time for repair. We report that in addition to the ataxia-telangiectasia mutated (ATM)-dependent pathway that controls the fast response, there is an ATM-independent pathway that controls the slow response to regulate the S-phase checkpoint after ionizing radiation in mammalian cells. The slow response of S-phase checkpoint, which is resistant to wortmannin, sensitive to caffeine and UCN-01, and related to cyclin-dependent kinase phosphorylation, is much stronger in CHK1 overexpressed cells, and it could be abolished by Chk1 antisense oligonucleotides. These results provide evidence that the ATM-independent slow response of S-phase checkpoint involves CHK1 pathway.

  11. Multimodal Responses of Self-Organized Circuitry in Electronically Phase Separated Materials

    DOE PAGESBeta

    Herklotz, Andreas; Guo, Hangwen; Wong, Anthony T.; Lee, Ho Nyung; Rack, Philip D.; Ward, Thomas Z.

    2016-07-13

    When confining an electronically phase we separated manganite film to the scale of its coexisting self-organized metallic and these insulating domains allows resistor-capacitor circuit-like responses while providing both electroresistive and magnetoresistive switching functionality.

  12. Experimental and theoretical approach for the clustering of globally coupled density oscillators based on phase response.

    PubMed

    Horie, Masanobu; Sakurai, Tatsunari; Kitahata, Hiroyuki

    2016-01-01

    We investigated the phase-response curve of a coupled system of density oscillators with an analytical approach. The behaviors of two-, three-, and four-coupled systems seen in the experiments were reproduced by the model considering the phase-response curve. Especially in a four-coupled system, the clustering state and its incidence rate as functions of the coupling strength are well reproduced with this approach. Moreover, we confirmed that the shape of the phase-response curve we obtained analytically was close to that observed in the experiment where a perturbation is added to a single-density oscillator. We expect that this approach to obtaining the phase-response curve is general in the sense that it could be applied to coupled systems of other oscillators such as electrical-circuit oscillators, metronomes, and so on.

  13. Truncated phase-space approach to polaron response.

    PubMed

    Sels, Dries; Brosens, Fons

    2014-01-01

    A method is presented to obtain the linear response coefficients of a system coupled to a bath. The method is based on a systematic truncation of the Liouville equation for the reduced distribution function. The first-order truncation results are expected to be accurate in the low-temperature and weak-coupling regime. Explicit expressions for the conductivity of the Fröhlich polaron are obtained, and the discrepancy between the Kadanoff and the Feynman-Hellwarth-Iddings-Platzman mobility is elucidated. PMID:24580189

  14. Intrinsic structure in Saturn's rings

    NASA Astrophysics Data System (ADS)

    Albers, N.

    2015-10-01

    Saturn's rings are the most prominent in our Solar system and one example of granular matter in space. Dominated by tides and inelastic collisions the system is highly flattened being almost 300000km wide while only tens of meters thick. Individual particles are composed of primarily water ice and range from microns to few tens of meters in size. Apparent patterns comprise ringlets, gaps, kinematic wakes, propellers, bending waves, and the winding spiral arms of density waves. These large-scale structures are perturbations foremost created by external as well as embedded moons. Observations made by the Cassini spacecraft currently in orbit around Saturn show these structures in unprecedented detail. But high-resolution measurements reveal the presence of small-scale structures throughout the system. These include self-gravity wakes (50-100m), overstable waves (100-300m), subkm structure at the A and B ring edges, "straw" and "ropy" structures (1-3km), and the C ring "ghosts". Most of these had not been anticipated and are found in perturbed regions, driven by resonances with external moons, where the system undergoes periodic phases of compression and relaxation that correlate with the presence of structure. High velocity dispersion and the presence of large clumps imply structure formation on time scales as short as one orbit (about 10 hours). The presence of these intrinsic structures is seemingly the response to varying local conditions such as internal density, optical depth, underlying particle size distribution, granular temperature, and distance from the central planet. Their abundance provides evidence for an active and dynamic ring system where aggregation and fragmentation are ongoing on orbital timescales. Thus a kinetic description of the rings may be more appropriate than the fluid one. I will present Cassini Ultraviolet Spectrometer (UVIS) High Speed Photometer (HSP) occultations, Voyager 1 and 2 Imaging Science Subsystem (ISS), and high

  15. Intrinsic Patterns of Human Activity

    NASA Astrophysics Data System (ADS)

    Hu, Kun; Ivanov, Plamen Ch.; Chen, Zhi; Hilton, Michael; Stanley, H. Eugene; Shea, Steven

    2003-03-01

    Activity is one of the defining features of life. Control of human activity is complex, being influenced by many factors both extrinsic and intrinsic to the body. The most obvious extrinsic factors that affect activity are the daily schedule of planned events, such as work and recreation, as well as reactions to unforeseen or random events. These extrinsic factors may account for the apparently random fluctuations in human motion observed over short time scales. The most obvious intrinsic factors are the body clocks including the circadian pacemaker that influences our sleep/wake cycle and ultradian oscillators with shorter time scales [2, 3]. These intrinsic rhythms may account for the underlying regularity in average activity level over longer periods of up to 24 h. Here we ask if the known extrinsic and intrinsic factors fully account for all complex features observed in recordings of human activity. To this end, we measure activity over two weeks from forearm motion in subjects undergoing their regular daily routine. Utilizing concepts from statistical physics, we demonstrate that during wakefulness human activity possesses previously unrecognized complex dynamic patterns. These patterns of activity are characterized by robust fractal and nonlinear dynamics including a universal probability distribution and long-range power-law correlations that are stable over a wide range of time scales (from minutes to hours). Surprisingly, we find that these dynamic patterns are unaffected by changes in the average activity level that occur within individual subjects throughout the day and on different days of the week, and between subjects. Moreover, we find that these patterns persist when the same subjects undergo time-isolation laboratory experiments designed to account for the phase of the circadian pacemaker, and control the known extrinsic factors by restricting behaviors and manipulating scheduled events including the sleep/wake cycle. We attribute these newly

  16. Creating diversified response profiles from a single quenchometric sensor element by using phase-resolved luminescence.

    PubMed

    Tehan, Elizabeth C; Bukowski, Rachel M; Chodavarapu, Vamsy P; Titus, Albert H; Cartwright, Alexander N; Bright, Frank V

    2015-01-05

    We report a new strategy for generating a continuum of response profiles from a single luminescence-based sensor element by using phase-resolved detection. This strategy yields reliable responses that depend in a predictable manner on changes in the luminescent reporter lifetime in the presence of the target analyte, the excitation modulation frequency, and the detector (lock-in amplifier) phase angle. In the traditional steady-state mode, the sensor that we evaluate exhibits a linear, positive going response to changes in the target analyte concentration. Under phase-resolved conditions the analyte-dependent response profiles: (i) can become highly non-linear; (ii) yield negative going responses; (iii) can be biphasic; and (iv) can exhibit super sensitivity (e.g., sensitivities up to 300 fold greater in comparison to steady-state conditions).

  17. Creating Diversified Response Profiles from a Single Quenchometric Sensor Element by Using Phase-Resolved Luminescence

    PubMed Central

    Tehan, Elizabeth C.; Bukowski, Rachel M.; Chodavarapu, Vamsy P.; Titus, Albert H.; Cartwright, Alexander N.; Bright, Frank V.

    2015-01-01

    We report a new strategy for generating a continuum of response profiles from a single luminescence-based sensor element by using phase-resolved detection. This strategy yields reliable responses that depend in a predictable manner on changes in the luminescent reporter lifetime in the presence of the target analyte, the excitation modulation frequency, and the detector (lock-in amplifier) phase angle. In the traditional steady-state mode, the sensor that we evaluate exhibits a linear, positive going response to changes in the target analyte concentration. Under phase-resolved conditions the analyte-dependent response profiles: (i) can become highly non-linear; (ii) yield negative going responses; (iii) can be biphasic; and (iv) can exhibit super sensitivity (e.g., sensitivities up to 300 fold greater in comparison to steady-state conditions). PMID:25569752

  18. Titanosilicates with Strong Phase-Matched Second Harmonic Generation Responses.

    PubMed

    Chao, Tzu-Ling; Chang, Wen-Jung; Wen, Shu-Han; Lin, Yu-Qing; Chang, Bor-Chen; Lii, Kwang-Hwa

    2016-07-27

    The search for new and efficient nonlinear optical (NLO) materials has been an active research because of their technological importance in laser applications. Although a large number of frequency-doubling oxides, phosphates, borates, and fluoride-containing borates were found, no transition-metal silicate with useful NLO properties has been reported. We have now synthesized and grown crystals of two new titanosilicates, Li2K4[(TiO)Si4O12] and Li2Rb4[(TiO)Si4O12], by using a flux and supercritical hydrothermal method. Their unique 3D framework structures contain highly compressed TiO5 square pyramids which are arranged one over the other to form infinite ···Ti-O···Ti-O straight chains with alternating short and long Ti-O distances. These two materials meet the requirements for efficient second harmonic generation including lack of center of inversion symmetry, large susceptibility, phase matching, transmitting at wavelengths of interest, resistant to laser damage, and thermally stable. These attributes make them very attractive for frequency-doubling materials. PMID:27416357

  19. Origins of asymmetric stress-strain response in phase transformations

    SciTech Connect

    Sehitoglu, H.; Gall, K.

    1997-12-31

    It has been determined that the transformation stress-strain behavior of CuZnAl and NiTi shape memory alloys is dependent on the applied stress state. The uniaxial compressive stress necessary to macroscopically trigger the transformation is approximately 34% (CuZnAl) and 26% (NiTi) larger than the required uniaxial tensile stress. For three dimensional stress states, the response of either alloy system is dependent on the directions of the dominant principal stresses along with the hydrostatic stress component of the stress state. The stress state effects are dominated by the favored growth and nucleation of more martensite plates in tension versus compression. The effect of different hydrostatic pressure levels between stress states on martensite plates volume change is considered small.

  20. Microsecond linear optical response in the unusual nematic phase of achiral bimesogens

    NASA Astrophysics Data System (ADS)

    Panov, V. P.; Balachandran, R.; Nagaraj, M.; Vij, J. K.; Tamba, M. G.; Kohlmeier, A.; Mehl, G. H.

    2011-12-01

    Some hydrocarbon linked mesogenic dimers are known to exhibit an additional nematic phase (Nx) below a conventional uniaxial nematic (Nu) phase. Although composed of non-chiral molecules, the Nx phase is found to exhibit linear (polar) switching under applied electric field. This switching has remarkably low response time of the order of a few microseconds. Two chiral domains with opposite handedness and consequently opposite responses are found in planar cells. Uniformly lying helix, electroclinic, and flexoelectric effects are given as possible causes for this intriguing phenomenon.

  1. Predicting Intrinsic Motivation

    ERIC Educational Resources Information Center

    Martens, Rob; Kirschner, Paul A.

    2004-01-01

    Intrinsic motivation can be predicted from participants' perceptions of the social environment and the task environment (Ryan & Deci, 2000)in terms of control, relatedness and competence. To determine the degree of independence of these factors 251 students in higher vocational education (physiotherapy and hotel management) indicated the extent to…

  2. Neuro-oscillatory phase alignment drives speeded multisensory response times: an electro-corticographic investigation.

    PubMed

    Mercier, Manuel R; Molholm, Sophie; Fiebelkorn, Ian C; Butler, John S; Schwartz, Theodore H; Foxe, John J

    2015-06-01

    Even simple tasks rely on information exchange between functionally distinct and often relatively distant neuronal ensembles. Considerable work indicates oscillatory synchronization through phase alignment is a major agent of inter-regional communication. In the brain, different oscillatory phases correspond to low- and high-excitability states. Optimally aligned phases (or high-excitability states) promote inter-regional communication. Studies have also shown that sensory stimulation can modulate or reset the phase of ongoing cortical oscillations. For example, auditory stimuli can reset the phase of oscillations in visual cortex, influencing processing of a simultaneous visual stimulus. Such cross-regional phase reset represents a candidate mechanism for aligning oscillatory phase for inter-regional communication. Here, we explored the role of local and inter-regional phase alignment in driving a well established behavioral correlate of multisensory integration: the redundant target effect (RTE), which refers to the fact that responses to multisensory inputs are substantially faster than to unisensory stimuli. In a speeded detection task, human epileptic patients (N = 3) responded to unisensory (auditory or visual) and multisensory (audiovisual) stimuli with a button press, while electrocorticography was recorded over auditory and motor regions. Visual stimulation significantly modulated auditory activity via phase reset in the delta and theta bands. During the period between stimulation and subsequent motor response, transient synchronization between auditory and motor regions was observed. Phase synchrony to multisensory inputs was faster than to unisensory stimulation. This sensorimotor phase alignment correlated with behavior such that stronger synchrony was associated with faster responses, linking the commonly observed RTE with phase alignment across a sensorimotor network. PMID:26041921

  3. A sterol C-14 reductase encoded by FgERG24B is responsible for the intrinsic resistance of Fusarium graminearum to amine fungicides.

    PubMed

    Liu, Xin; Fu, Jing; Yun, Yingzi; Yin, Yanni; Ma, Zhonghua

    2011-06-01

    Fusarium graminearum, the causal agent of wheat head blight, shows intrinsic resistance to amine fungicides. It is commonly accepted that the amines target sterol C-14 reductase and sterol Δ(8)-Δ(7) isomerase of ergosterol biosynthesis, encoded by the genes ERG24 and ERG2, respectively. Analysis of the genome sequence of F. graminearum revealed that the fungus contains two paralogous FgERG24 genes (FgERG24A and FgERG24B), which are homologous to the ERG24 of Saccharomyces cerevisiae. In this study, we disrupted FgERG24A and FgERG24B in F. graminearum. Compared to the wild-type strain HN9-1, FgERG24A and FgERG24B deletion mutants did not show recognizable phenotypic changes in mycelial growth on potato dextrose agar or in virulence on wheat heads. HPLC analysis showed that the amount of ergosterol in FgERG24A or FgERG24B deletion mutants was not significantly different from that in the wild-type strain. These results indicate that neither of the two genes is essential for growth, pathogenicity or ergosterol biosynthesis in F. graminearum. FgERG24B deletion mutants exhibited significantly increased sensitivity to amine fungicides, including tridemorph, fenpropidin and spiroxamine, but not to non-amine fungicides. In contrast, FgERG24A deletion mutants did not show changed sensitivity to any amine tested. The resistance of the FgERG24B deletion mutant to amines was restored by genetic complementation of the mutant with wild-type FgERG24B. These results indicate that FgERG24B controls the intrinsic resistance of F. graminearum to amines. The finding of this study provides new insights into amine resistance in filamentous fungi.

  4. Association between subjective and cortisol stress response depends on the menstrual cycle phase.

    PubMed

    Duchesne, Annie; Pruessner, Jens C

    2013-12-01

    The relation between the physiologic and subjective stress responses is inconsistently reported across studies. Menstrual cycle phases variations have been found to influence the psychophysiological stress response; however little is known about possible cycle phase differences in the relationship between physiological and subjective stress responses. This study examined the effect of menstrual cycle phase in the association between subjective stress and physiological response. Forty-five women in either the follicular (n=21) or the luteal phase of the menstrual cycle were exposed to a psychosocial stress task. Salivary cortisol, cardiovascular, and subjective stress were assessed throughout the experiment. Results revealed a significant group difference in the association between peak levels of cortisol and post task subjective stress. In women in the follicular phase a negative association was observed (r(2)=0.199, p=0.04), while this relation was positive in the group of women in the luteal phase (r(2)=0.227, p=0.02). These findings suggest a possible role of sex hormones in modulating the cortisol stress response function in emotion regulation.

  5. Acute phase response induced following tumor treatment by photodynamic therapy: relevance for the therapy outcome

    NASA Astrophysics Data System (ADS)

    Korbelik, Mladen; Merchant, Soroush; Stott, Brandon; Cecic, Ivana; Payne, Peter; Sun, Jinghai

    2006-02-01

    Acute phase response is an effector process orchestrated by the innate immune system for the optimal mobilization of the resources of the organism distant from the local insult site needed in the execution of a host-protecting reaction. Our research has shown that mice bearing tumors treated by photodynamic therapy (PDT) exhibit the three major hallmarks of acute phase response: release of acute phase reactants, neutrophilia, and pituitary/adrenal axis activation. Of particular interest in this study were acute phase proteins that have a pivotal role in the clearance of dead cells, since the occurrence of this process in PDT-treated tumors emerges as a critical event in the course of PDT-associated host response. It is shown that this type of acute phase reactants, including complement proteins (C3, C5, C9, mannose-binding lectin, and ficolin A) and related pentraxins (serum amyloid P component and PTX3), are upregulated following tumor PDT and accumulate in the targeted lesions. Based on the recently accumulated experimental evidence it is definitely established that the acute phase response is manifested in the hosts bearing PDT-treated tumors and it is becoming clear that this effector process is an important element of PDT-associated host response bearing in impact on the eventual outcome of this therapy.

  6. Effects of low-spatial-frequency response of phase plates on TEM imaging

    NASA Astrophysics Data System (ADS)

    Edgcombe, C. J.

    2015-10-01

    Images of simple objects produced by a perfect lens and a phase plate have been calculated by use of Abbe theory for Foucault, Hilbert and Zernike phase plates. The results show that with a Zernike plate, white outlines and ringing like those observed previously can be caused by the beam hole, which limits the low-spatial-frequency response of the system even when the lens behaves perfectly. When the change of phase added by the phase plate is distributed over a range of radius rather than a simple step, the unwanted effects are substantially reduced.

  7. Survival of Campylobacter jejuni during Stationary Phase: Evidence for the Absence of a Phenotypic Stationary-Phase Response

    PubMed Central

    Kelly, Alison F.; Park, Simon F.; Bovill, Richard; Mackey, Bernard M.

    2001-01-01

    When Campylobacter jejuni NCTC 11351 was grown microaerobically in rich medium at 39°C, entry into stationary phase was followed by a rapid decline in viable numbers to leave a residual population of 1% of the maximum number or less. Loss of viability was preceded by sublethal injury, which was seen as a loss of the ability to grow on media containing 0.1% sodium deoxycholate or 1% sodium chloride. Resistance of cells to mild heat stress (50°C) or aeration was greatest in exponential phase and declined during early stationary phase. These results show that C. jejuni does not mount the normal phenotypic stationary-phase response which results in enhanced stress resistance. This conclusion is consistent with the absence of rpoS homologues in the recently reported genome sequence of this species and their probable absence from strain NCTC 11351. During prolonged incubation of C. jejuni NCTC 11351 in stationary phase, an unusual pattern of decreasing and increasing heat resistance was observed that coincided with fluctuations in the viable count. During stationary phase of Campylobacter coli UA585, nonmotile variants and those with impaired ability to form coccoid cells were isolated at high frequency. Taken together, these observations suggest that stationary-phase cultures of campylobacters are dynamic populations and that this may be a strategy to promote survival in at least some strains. Investigation of two spontaneously arising variants (NM3 and SC4) of C. coli UA585 showed that a reduced ability to form coccoid cells did not affect survival under nongrowth conditions. PMID:11319108

  8. Psychosocial Responses During Different Phases of Sport-Injury Rehabilitation: A Qualitative Study

    PubMed Central

    Clement, Damien; Arvinen-Barrow, Monna; Fetty, Tera

    2015-01-01

    Context: Athletic trainers have traditionally conceptualized rehabilitation programs in terms of 3 distinct physiologic phases; however, these phases appear to neglect athletes' psychosocial responses to their injuries. Objective: To document injured athletes' psychosocial responses during the different phases of injury rehabilitation. Design: Qualitative study. Setting: National Collegiate Athletic Association Division II university in the mid-Atlantic region of the United States. Patients or Other Participants: A total of 8 previously injured athletes (4 men and 4 women) participated in the study. Data Collection and Analysis: We collected participant data by using semistructured interviews, transcribed verbatim and analyzed by directed content analysis. Established themes were triangulated to determine trustworthiness. Results: Initially, athletes' cognitive appraisals were predominately negative in nature, leading to negative emotions. These appraisals changed after diagnosis and when moving to the reaction-to-rehabilitation phase and the reaction-to-sport phase. During the reaction-to-rehabilitation phase, athletes reported mixed cognitive appraisals and identified frustration as the main emotional response. When returning to sport, athletes reflected on the lessons learned, yet they expressed some doubts related to their ability to return to play. These cognitive appraisals served as a precursor to the resulting emotional responses of nervousness and reinjury anxiety, as well as excitement. Throughout the various phases of rehabilitation, athletes reported seeking out social support: initially from significant others and then from their athletic trainers during the reaction-to-rehabilitation phase. Conclusions: The results appear to support the use of the integrated model of psychological response to sport injury and the rehabilitation process and the 3 phases of rehabilitation as a framework for understanding how physical and psychosocial factors may

  9. The effects of digitizing rate and phase distortion errors on the shock response spectrum

    NASA Technical Reports Server (NTRS)

    Wise, J. H.

    1983-01-01

    Some of the methods used for acquisition and digitization of high-frequency transients in the analysis of pyrotechnic events, such as explosive bolts for spacecraft separation, are discussed with respect to the reduction of errors in the computed shock response spectrum. Equations are given for maximum error as a function of the sampling rate, phase distortion, and slew rate, and the effects of the characteristics of the filter used are analyzed. A filter is noted to exhibit good passband amplitude, phase response, and response to a step function is a compromise between the flat passband of the elliptic filter and the phase response of the Bessel filter; it is suggested that it be used with a sampling rate of 10f (5 percent).

  10. Ab Initio Infrared Spectra and Electronic Response Calculations for the Insulating Phases of VO2

    NASA Astrophysics Data System (ADS)

    Hendriks, Christopher; Huffman, Tyler; Walter, Eric; Qazilbash, Mumtaz; Krakauer, Henry

    Previous studies have shown that, under doping or tensile strain and upon heating, the well-known vanadium dioxide (VO2) transition from an insulating monoclinic (M1) to a metallic rutile (R) phase progresses through a triclinic symmetry (T) phase and a magnetic monoclinic phase (M2), both of which are insulating. Structurally, this progression from M1 to R through T and M2 can be characterized by the progressive breaking of the V dimers. Investigation of the effect of these structural changes on the insulating phases of VO2 may help resolve questions surrounding the long-debated issue of the respective roles of electronic correlation and Peierls mechanisms in driving the MIT. We investigated electronic and vibrational properties of the insulating phases of VO2 in the framework of DFT+U. We will present ab initio calculations of infrared spectra and optical electronic responses for the insulating phases and compare these to available experimental measurements. Supported by ONR.

  11. Liquid demixing of intrinsically disordered proteins is seeded by poly(ADP-ribose)

    PubMed Central

    Altmeyer, Matthias; Neelsen, Kai J.; Teloni, Federico; Pozdnyakova, Irina; Pellegrino, Stefania; Grøfte, Merete; Rask, Maj-Britt Druedahl; Streicher, Werner; Jungmichel, Stephanie; Nielsen, Michael Lund; Lukas, Jiri

    2015-01-01

    Intrinsically disordered proteins can phase separate from the soluble intracellular space, and tend to aggregate under pathological conditions. The physiological functions and molecular triggers of liquid demixing by phase separation are not well understood. Here we show in vitro and in vivo that the nucleic acid-mimicking biopolymer poly(ADP-ribose) (PAR) nucleates intracellular liquid demixing. PAR levels are markedly induced at sites of DNA damage, and we provide evidence that PAR-seeded liquid demixing results in rapid, yet transient and fully reversible assembly of various intrinsically disordered proteins at DNA break sites. Demixing, which relies on electrostatic interactions between positively charged RGG repeats and negatively charged PAR, is amplified by aggregation-prone prion-like domains, and orchestrates the earliest cellular responses to DNA breakage. We propose that PAR-seeded liquid demixing is a general mechanism to dynamically reorganize the soluble nuclear space with implications for pathological protein aggregation caused by derailed phase separation. PMID:26286827

  12. Enhanced response to ozone exposure during the follicular phase of the menstrual cycle

    SciTech Connect

    Fox, S.D.; Adams, W.C.; Brookes, K.A.; Lasley, B.L. )

    1993-08-01

    Exposure to ozone (O[sub 3]), a toxic component of photochemical smog, results in significant airway inflammation, respiratory discomfort, and pulmonary function impairment. These effects can be reduced via pretreatment with anti-inflammatory agents. Progesterone, a gonadal steroid, is known to reduce general inflammation in the uterine endometrium. However, it is not known whether fluctuation in blood levels of progesterone, which are experienced during the normal female menstrual cycle, could alter O[sub 3] inflammatory-induced pulmonary responses. In this study, we tested the hypothesis that young, adult females are more responsive to O[sub 3] inhalation with respect to pulmonary function impairment during their follicular (F) menstrual phase when progesterone levels are lowest that during their mid-luteal (ML) phase when progesterone levels are highest. Nine subjects with normal ovarian function were exposed in random order for 1 hour each to filtered air and to 0.30 ppm O[sub 3] in their F and ML menstrual phases. Ozone responsiveness was measured by percent change in pulmonary function from pre- to postexposure. Significant gas concentration effects (filtered air versus O[sub 3]) were observed for forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV[sub 1]), and forced expiratory flow between 25 and 75% of FVC (FEF[sub 25-75]), showed a significant menstrual phase and gas concentration interaction effect, with larger decrements observed in the F menstrual phase when progesterone concentrations were significantly lower. We conclude that young, adult females appear to be more responsive to acute O[sub 3] exposure during the F phase than during the ML phase of their menstrual cycles. This difference in pulmonary function response could be related to the anti-inflammatory effects of increased progesterone concentrations during the luteal phase.

  13. Observation of spectrum effect on the measurement of intrinsic error field on EAST

    NASA Astrophysics Data System (ADS)

    Wang, Hui-Hui; Sun, You-Wen; Qian, Jin-Ping; Shi, Tong-Hui; Shen, Biao; Gu, Shuai; Liu, Yue-Qiang; Guo, Wen-Feng; Chu, Nan; He, Kai-Yang; Jia, Man-Ni; Chen, Da-Long; Xue, Min-Min; Ren, Jie; Wang, Yong; Sheng, Zhi-Cai; Xiao, Bing-Jia; Luo, Zheng-Ping; Liu, Yong; Liu, Hai-Qing; Zhao, Hai-Lin; Zeng, Long; Gong, Xian-Zu; Liang, Yun-Feng; Wan, Bao-Nian; The EAST Team

    2016-06-01

    Intrinsic error field on EAST is measured using the ‘compass scan’ technique with different n  =  1 magnetic perturbation coil configurations in ohmically heated discharges. The intrinsic error field measured using a non-resonant dominated spectrum with even connection of the upper and lower resonant magnetic perturbation coils is of the order {{b}r2,1}/{{B}\\text{T}}≃ {{10}-5} and the toroidal phase of intrinsic error field is around {{60}{^\\circ}} . A clear difference between the results using the two coil configurations, resonant and non-resonant dominated spectra, is observed. The ‘resonant’ and ‘non-resonant’ terminology is based on vacuum modeling. The penetration thresholds of the non-resonant dominated cases are much smaller than that of the resonant cases. The difference of penetration thresholds between the resonant and non-resonant cases is reduced by plasma response modeling using the MARS-F code.

  14. Associations between adrenocortical activity and nicotine response in female smokers by menstrual phase.

    PubMed

    Huttlin, Eileen A; Allen, Alicia M; Tosun, Nicole L; Allen, Sharon S; al'Absi, Mustafa

    2015-11-01

    Previous research suggests that menstrual phase may influence smoking-related symptomatology. The present study analyzes the relationship between menstrual phase and salivary cortisol with subjective responses to nicotine among female smokers during ad libitum smoking. We hypothesize higher cortisol levels would be associated with increased positive and decreased negative subjective responses to nicotine. We also expected that these associations would vary by menstrual phase. Females aged 18-40 who smoke at least five cigarettes/day, reported regular menstrual cycles and did not use exogenous hormones or psychotropic medications were enrolled into a controlled cross-over trial. Participants completed identical data collection procedures during follicular (F) and luteal (L) phases; including self-collected salivary cortisol samples and completion of a nicotine response lab session involving administration of nicotine nasal spray and monitoring of subjective response to nicotine via the Subjective State Scale and Visual Analog Scale. Participants (n = 116) were 29.1 ± 6.9 years old and smoked an average of 12.3 ± 5.5 cigarettes daily. During F phase, higher morning cortisol was associated with decreased negative affect (r = -0.21, p = 0.03), withdrawal (r = -0.30, p < 0.01) and increased relaxation (r = 0.24, p = 0.02) after administration of nicotine nasal spray. Conversely, during L phase, higher morning cortisol was associated with a decrease in head rush (r = -0.26, p = 0.01) and urge to smoke (r = -0.21, p = 0.04) after administration of nicotine nasal spray. Similar associations between greater diurnal cortisol variation and response to nicotine were seen. These observations indicate that cortisol may have a phase-specific association with some subjective responses to nicotine in female smokers. Additional research should explore how these relationships may influence smoking cessation efforts.

  15. A phase response curve to single bright light pulses in human subjects

    NASA Technical Reports Server (NTRS)

    Khalsa, Sat Bir S.; Jewett, Megan E.; Cajochen, Christian; Czeisler, Charles A.

    2003-01-01

    The circadian pacemaker is differentially sensitive to the resetting effects of retinal light exposure, depending upon the circadian phase at which the light exposure occurs. Previously reported human phase response curves (PRCs) to single bright light exposures have employed small sample sizes, and were often based on relatively imprecise estimates of circadian phase and phase resetting. In the present study, 21 healthy, entrained subjects underwent pre- and post-stimulus constant routines (CRs) in dim light (approximately 2-7 lx) with maintained wakefulness in a semi-recumbent posture. The 6.7 h bright light exposure stimulus consisted of alternating 6 min fixed gaze (approximately 10 000 lx) and free gaze (approximately 5000-9000 lx) exposures. Light exposures were scheduled across the circadian cycle in different subjects so as to derive a PRC. Plasma melatonin was used to determine the phase of the onset, offset, and midpoint of the melatonin profiles during the CRs. Phase shifts were calculated as the difference in phase between the pre- and post-stimulus CRs. The resultant PRC of the midpoint of the melatonin rhythm revealed a characteristic type 1 PRC with a significant peak-to-trough amplitude of 5.02 h. Phase delays occurred when the light stimulus was centred prior to the critical phase at the core body temperature minimum, phase advances occurred when the light stimulus was centred after the critical phase, and no phase shift occurred at the critical phase. During the subjective day, no prolonged 'dead zone' of photic insensitivity was apparent. Phase shifts derived using the melatonin onsets showed larger magnitudes than those derived from the melatonin offsets. These data provide a comprehensive characterization of the human PRC under highly controlled laboratory conditions.

  16. In Vitro Drug Response and Efflux Transporters Associated with Drug Resistance in Pediatric High Grade Glioma and Diffuse Intrinsic Pontine Glioma

    PubMed Central

    Veringa, Susanna J. E.; Biesmans, Dennis; van Vuurden, Dannis G.; Jansen, Marc H. A.; Wedekind, Laurine E.; Horsman, Ilona; Wesseling, Pieter; Vandertop, William Peter; Noske, David P.; Kaspers, GertJan J. L.; Hulleman, Esther

    2013-01-01

    Pediatric high-grade gliomas (pHGG), including diffuse intrinsic pontine gliomas (DIPG), are the leading cause of cancer-related death in children. While it is clear that surgery (if possible), and radiotherapy are beneficial for treatment, the role of chemotherapy for these tumors is still unclear. Therefore, we performed an in vitro drug screen on primary glioma cells, including three DIPG cultures, to determine drug sensitivity of these tumours, without the possible confounding effect of insufficient drug delivery. This screen revealed a high in vitro cytotoxicity for melphalan, doxorubicine, mitoxantrone, and BCNU, and for the novel, targeted agents vandetanib and bortezomib in pHGG and DIPG cells. We subsequently determined the expression of the drug efflux transporters P-gp, BCRP1, and MRP1 in glioma cultures and their corresponding tumor tissues. Results indicate the presence of P-gp, MRP1 and BCRP1 in the tumor vasculature, and expression of MRP1 in the glioma cells themselves. Our results show that pediatric glioma and DIPG tumors per se are not resistant to chemotherapy. Treatment failure observed in clinical trials, may rather be contributed to the presence of drug efflux transporters that constitute a first line of drug resistance located at the blood-brain barrier or other resistance mechanism. As such, we suggest that alternative ways of drug delivery may offer new possibilities for the treatment of pediatric high-grade glioma patients, and DIPG in particular. PMID:23637844

  17. Tailoring Vacancies Far Beyond Intrinsic Levels Changes the Carrier Type and Optical Response in Monolayer MoSe2-x Crystals.

    PubMed

    Mahjouri-Samani, Masoud; Liang, Liangbo; Oyedele, Akinola; Kim, Yong-Sung; Tian, Mengkun; Cross, Nicholas; Wang, Kai; Lin, Ming-Wei; Boulesbaa, Abdelaziz; Rouleau, Christopher M; Puretzky, Alexander A; Xiao, Kai; Yoon, Mina; Eres, Gyula; Duscher, Gerd; Sumpter, Bobby G; Geohegan, David B

    2016-08-10

    Defect engineering has been a critical step in controlling the transport characteristics of electronic devices, and the ability to create, tune, and annihilate defects is essential to enable the range of next-generation devices. Whereas defect formation has been well-demonstrated in three-dimensional semiconductors, similar exploration of the heterogeneity in atomically thin two-dimensional semiconductors and the link between their atomic structures, defects, and properties has not yet been extensively studied. Here, we demonstrate the growth of MoSe2-x single crystals with selenium (Se) vacancies far beyond intrinsic levels, up to ∼20%, that exhibit a remarkable transition in electrical transport properties from n- to p-type character with increasing Se vacancy concentration. A new defect-activated phonon band at ∼250 cm(-1) appears, and the A1g Raman characteristic mode at 240 cm(-1) softens toward ∼230 cm(-1) which serves as a fingerprint of vacancy concentration in the crystals. We show that post-selenization using pulsed laser evaporated Se atoms can repair Se-vacant sites to nearly recover the properties of the pristine crystals. First-principles calculations reveal the underlying mechanisms for the corresponding vacancy-induced electrical and optical transitions.

  18. Tailoring Vacancies Far Beyond Intrinsic Levels Changes the Carrier Type and Optical Response in Monolayer MoSe 2-x Crystals

    DOE PAGESBeta

    Mahjouri-Samani, Masoud; Liang, Liangbo; Oyedele, Akinola; Kim, Yong-Sung; Tian, Mengkun; Cross, Nicholas; Wang, Kai; Lin, Ming-Wei; Boulesbaa, Abdelaziz; Rouleau, Christopher M.; et al

    2016-07-14

    Defect engineering has been a critical step in controlling the transport characteristics of electronic devices, and the ability to create, tune, and annihilate defects is essential to enable the range of next-generation devices. Whereas defect formation has been well-demonstrated in three-dimensional semiconductors, similar exploration of the heterogeneity in atomically thin two-dimensional semiconductors and the link between their atomic structures, defects, and properties has not yet been extensively studied. In this paper, we demonstrate the growth of MoSe2–x single crystals with selenium (Se) vacancies far beyond intrinsic levels, up to ~20%, that exhibit a remarkable transition in electrical transport properties frommore » n- to p-type character with increasing Se vacancy concentration. A new defect-activated phonon band at ~250 cm-1 appears, and the A1g Raman characteristic mode at 240 cm-1 softens toward ~230 cm-1 which serves as a fingerprint of vacancy concentration in the crystals. We show that post-selenization using pulsed laser evaporated Se atoms can repair Se-vacant sites to nearly recover the properties of the pristine crystals. Finally, first-principles calculations reveal the underlying mechanisms for the corresponding vacancy-induced electrical and optical transitions.« less

  19. Clinical Practice Guideline for the Treatment of Intrinsic Circadian Rhythm Sleep-Wake Disorders: Advanced Sleep-Wake Phase Disorder (ASWPD), Delayed Sleep-Wake Phase Disorder (DSWPD), Non-24-Hour Sleep-Wake Rhythm Disorder (N24SWD), and Irregular Sleep-Wake Rhythm Disorder (ISWRD). An Update for 2015

    PubMed Central

    Auger, R. Robert; Burgess, Helen J.; Emens, Jonathan S.; Deriy, Ludmila V.; Thomas, Sherene M.; Sharkey, Katherine M.

    2015-01-01

    A systematic literature review and meta-analyses (where appropriate) were performed and the GRADE approach was used to update the previous American Academy of Sleep Medicine Practice Parameters on the treatment of intrinsic circadian rhythm sleep-wake disorders. Available data allowed for positive endorsement (at a second-tier degree of confidence) of strategically timed melatonin (for the treatment of DSWPD, blind adults with N24SWD, and children/ adolescents with ISWRD and comorbid neurological disorders), and light therapy with or without accompanying behavioral interventions (adults with ASWPD, children/adolescents with DSWPD, and elderly with dementia). Recommendations against the use of melatonin and discrete sleep-promoting medications are provided for demented elderly patients, at a second- and first-tier degree of confidence, respectively. No recommendations were provided for remaining treatments/ populations, due to either insufficient or absent data. Areas where further research is needed are discussed. Citation: Auger RR, Burgess HJ, Emens JS, Deriy LV, Thomas SM, Sharkey KM. Clinical practice guideline for the treatment of intrinsic circadian rhythm sleep-wake disorders: advanced sleep-wake phase disorder (ASWPD), delayed sleep-wake phase disorder (DSWPD), non-24-hour sleep-wake rhythm disorder (N24SWD), and irregular sleep-wake rhythm disorder (ISWRD). An update for 2015. J Clin Sleep Med 2015;11(10):1199–1236. PMID:26414986

  20. Ultrafast terahertz-induced response of GeSbTe phase-change materials

    SciTech Connect

    Shu, Michael J.; Zalden, Peter; Chen, Frank; Weems, Ben; Chatzakis, Ioannis; Xiong, Feng; Jeyasingh, Rakesh; Pop, Eric; Philip Wong, H.-S.; Hoffmann, Matthias C.; Wuttig, Matthias; Lindenberg, Aaron M.

    2014-06-23

    The time-resolved ultrafast electric field-driven response of crystalline and amorphous GeSbTe films has been measured all-optically, pumping with single-cycle terahertz pulses as a means of biasing phase-change materials on a sub-picosecond time-scale. Utilizing the near-band-gap transmission as a probe of the electronic and structural response below the switching threshold, we observe a field-induced heating of the carrier system and resolve the picosecond-time-scale energy relaxation processes and their dependence on the sample annealing condition in the crystalline phase. In the amorphous phase, an instantaneous electroabsorption response is observed, quadratic in the terahertz field, followed by field-driven lattice heating, with Ohmic behavior up to 200 kV/cm.

  1. Discrimination of Speech Stimuli Based on Neuronal Response Phase Patterns Depends on Acoustics But Not Comprehension

    PubMed Central

    Poeppel, David

    2010-01-01

    Speech stimuli give rise to neural activity in the listener that can be observed as waveforms using magnetoencephalography. Although waveforms vary greatly from trial to trial due to activity unrelated to the stimulus, it has been demonstrated that spoken sentences can be discriminated based on theta-band (3–7 Hz) phase patterns in single-trial response waveforms. Furthermore, manipulations of the speech signal envelope and fine structure that reduced intelligibility were found to produce correlated reductions in discrimination performance, suggesting a relationship between theta-band phase patterns and speech comprehension. This study investigates the nature of this relationship, hypothesizing that theta-band phase patterns primarily reflect cortical processing of low-frequency (<40 Hz) modulations present in the acoustic signal and required for intelligibility, rather than processing exclusively related to comprehension (e.g., lexical, syntactic, semantic). Using stimuli that are quite similar to normal spoken sentences in terms of low-frequency modulation characteristics but are unintelligible (i.e., their time-inverted counterparts), we find that discrimination performance based on theta-band phase patterns is equal for both types of stimuli. Consistent with earlier findings, we also observe that whereas theta-band phase patterns differ across stimuli, power patterns do not. We use a simulation model of the single-trial response to spoken sentence stimuli to demonstrate that phase-locked responses to low-frequency modulations of the acoustic signal can account not only for the phase but also for the power results. The simulation offers insight into the interpretation of the empirical results with respect to phase-resetting and power-enhancement models of the evoked response. PMID:20484530

  2. Caffeine in hot drinks elicits cephalic phase responses involving cardiac activity.

    PubMed

    McMullen, Michael K; Whitehouse, Julie M; Shine, Gillian; Whitton, Peter A; Towell, Anthony

    2012-09-01

    Caffeine stimulates both oropharyngeal and gut bitter taste receptors (hTAS2Rs) and so has the potential to elicit reflex autonomic responses. Coffee containing 130 mg caffeine has been reported to increase heart rate for 30 min post-ingestion. Whereas added-caffeine, in doses of 25 to 200 mg, ingested with decaffeinated coffee/tea decreases heart rate 10 to 30 min post-ingestion. This study aimed to clarify caffeine's chemosensory impact. Double-espresso coffees were compared to a placebo-control capsule in a double-blind between-measures design. Coffees tested were regular coffee (130 mg caffeine) and decaffeinated coffee with added-caffeine (0, 67 and 134 mg). Cardiovascular measures from three post-ingestion phases: 1) 0 to 5; 2) 10 to 15; and 3) 25 to 30 min; were compared to pre-ingestion measures. Participants comprised 11 women in the control group and 10 women in the test group. Decaffeinated coffee elicited no changes. Decaffeinated coffee with 67 mg caffeine: decreased dp/dt in Phase 1. Decaffeinated coffee with 134 mg caffeine: increased heart rate in Phases 1 and 2; decreased spontaneous baroreflex sensitivity in Phase 1; and increased diastolic pressure in Phases 2 and 3. Regular coffee: increased heart rate in Phases 1 and 2; decreased dp/dt in all phases; and decreased systolic pressure in Phase 1. Caffeine is the substance in regular coffee which elicits chemosensory autonomic reflex responses, which involves heart activity and the baroreflex. Compared to the caffeine in regular coffee, added-caffeine elicits somewhat different chemosensory responses including a more pronounced pressor effect and resetting of the baroreflex. Caffeine in commonly consumed amounts, as well as modulating body processes by blocking adenosine receptors, can elicit reflex autonomic responses during the ingestion of caffeinated drinks. It is plausible that caffeine stimulates hTAS2Rs, during the ingestion of coffee, eliciting cephalic phase responses. These cephalic phase

  3. Caffeine in hot drinks elicits cephalic phase responses involving cardiac activity.

    PubMed

    McMullen, Michael K; Whitehouse, Julie M; Shine, Gillian; Whitton, Peter A; Towell, Anthony

    2012-09-01

    Caffeine stimulates both oropharyngeal and gut bitter taste receptors (hTAS2Rs) and so has the potential to elicit reflex autonomic responses. Coffee containing 130 mg caffeine has been reported to increase heart rate for 30 min post-ingestion. Whereas added-caffeine, in doses of 25 to 200 mg, ingested with decaffeinated coffee/tea decreases heart rate 10 to 30 min post-ingestion. This study aimed to clarify caffeine's chemosensory impact. Double-espresso coffees were compared to a placebo-control capsule in a double-blind between-measures design. Coffees tested were regular coffee (130 mg caffeine) and decaffeinated coffee with added-caffeine (0, 67 and 134 mg). Cardiovascular measures from three post-ingestion phases: 1) 0 to 5; 2) 10 to 15; and 3) 25 to 30 min; were compared to pre-ingestion measures. Participants comprised 11 women in the control group and 10 women in the test group. Decaffeinated coffee elicited no changes. Decaffeinated coffee with 67 mg caffeine: decreased dp/dt in Phase 1. Decaffeinated coffee with 134 mg caffeine: increased heart rate in Phases 1 and 2; decreased spontaneous baroreflex sensitivity in Phase 1; and increased diastolic pressure in Phases 2 and 3. Regular coffee: increased heart rate in Phases 1 and 2; decreased dp/dt in all phases; and decreased systolic pressure in Phase 1. Caffeine is the substance in regular coffee which elicits chemosensory autonomic reflex responses, which involves heart activity and the baroreflex. Compared to the caffeine in regular coffee, added-caffeine elicits somewhat different chemosensory responses including a more pronounced pressor effect and resetting of the baroreflex. Caffeine in commonly consumed amounts, as well as modulating body processes by blocking adenosine receptors, can elicit reflex autonomic responses during the ingestion of caffeinated drinks. It is plausible that caffeine stimulates hTAS2Rs, during the ingestion of coffee, eliciting cephalic phase responses. These cephalic phase

  4. Phase response of the Arabidopsis thaliana circadian clock to light pulses of different wavelengths.

    PubMed

    Ohara, Takayuki; Fukuda, Hirokazu; Tokuda, Isao T

    2015-04-01

    Light is known as one of the most powerful environmental time cues for the circadian system. The quality of light is characterized by its intensity and wavelength. We examined how the phase response of Arabidopsis thaliana depends on the wavelength of the stimulus light and the type of light perturbation. Using transgenic A. thaliana expressing a luciferase gene, we monitored the rhythm of the bioluminescence signal. We stimulated the plants under constant red light using 3 light perturbation treatments: (1) increasing the red light intensity, (2) turning on a blue light while turning off the red light, and (3) turning on a blue light while keeping the red light on. To examine the phase response properties, we generated a phase transition curve (PTC), which plots the phase after the perturbation as a function of the phase before the perturbation. To evaluate the effect of the 3 light perturbation treatments, we simulated PTCs using a mathematical model of the plant circadian clock and fitted the simulated PTCs to the experimentally measured PTCs. Among the 3 treatments, perturbation (3) provided the strongest stimulus. The results indicate that the color of the stimulus light and the type of pulse administration affect the phase response in a complex manner. Moreover, the results suggest the involvement of interaction between red and blue light signaling pathways in resetting of the plant circadian clock.

  5. Increased vasopressin and adrenocorticotropin responses to stress in the midluteal phase of the menstrual cycle.

    PubMed

    Altemus, M; Roca, C; Galliven, E; Romanos, C; Deuster, P

    2001-06-01

    Accumulating evidence indicates that gonadal steroids modulate functioning of the hypothalamic-pituitary-adrenal (HPA) axis, which has been closely linked to the pathophysiology of anxiety and depression. However, the effect of the natural menstrual cycle on HPA axis responsivity to stress has not been clearly described. In nine healthy women, metabolic and hormonal responses to treadmill exercise stress during the early follicular phase of the menstrual cycle, when gonadal steroid levels are low, were compared with responses in the midluteal phase of the cycle, when both progesterone and estrogen levels are relatively high. Exercise intensity was gradually increased over 20 min to reach 90% of each subject's maximal oxygen consumption during the final 5 min of exercise. Basal plasma lactate, glucose, ACTH, vasopressin, oxytocin, and cortisol levels were similar in the two cycle phases. However, in response to exercise stress, women in the midluteal phase had enhanced ACTH (P < 0.0001), vasopressin (P < 0.01), and glucose (P < 0.001) secretion. These findings suggest that relatively low levels of gonadal steroids during the early follicular phase of the menstrual cycle provide protection from the impact of stress on the HPA axis.

  6. Increased vasopressin and adrenocorticotropin responses to stress in the midluteal phase of the menstrual cycle.

    PubMed

    Altemus, M; Roca, C; Galliven, E; Romanos, C; Deuster, P

    2001-06-01

    Accumulating evidence indicates that gonadal steroids modulate functioning of the hypothalamic-pituitary-adrenal (HPA) axis, which has been closely linked to the pathophysiology of anxiety and depression. However, the effect of the natural menstrual cycle on HPA axis responsivity to stress has not been clearly described. In nine healthy women, metabolic and hormonal responses to treadmill exercise stress during the early follicular phase of the menstrual cycle, when gonadal steroid levels are low, were compared with responses in the midluteal phase of the cycle, when both progesterone and estrogen levels are relatively high. Exercise intensity was gradually increased over 20 min to reach 90% of each subject's maximal oxygen consumption during the final 5 min of exercise. Basal plasma lactate, glucose, ACTH, vasopressin, oxytocin, and cortisol levels were similar in the two cycle phases. However, in response to exercise stress, women in the midluteal phase had enhanced ACTH (P < 0.0001), vasopressin (P < 0.01), and glucose (P < 0.001) secretion. These findings suggest that relatively low levels of gonadal steroids during the early follicular phase of the menstrual cycle provide protection from the impact of stress on the HPA axis. PMID:11397850

  7. Phase Synchronization and Desynchronization of Structural Response Induced by Turbulent and External Sound

    NASA Technical Reports Server (NTRS)

    Maestrello, Lucio

    2002-01-01

    Acoustic and turbulent boundary layer flow loadings over a flexible structure are used to study the spatial-temporal dynamics of the response of the structure. The stability of the spatial synchronization and desynchronization by an active external force is investigated with an array of coupled transducers on the structure. In the synchronous state, the structural phase is locked, which leads to the formation of spatial patterns while the amplitude peaks exhibit chaotic behaviors. Large amplitude, spatially symmetric loading is superimposed on broadband, but in the desynchronized state, the spectrum broadens and the phase space is lost. The resulting pattern bears a striking resemblance to phase turbulence. The transition is achieved by using a low power external actuator to trigger broadband behaviors from the knowledge of the external acoustic load inducing synchronization. The changes are made favorably and efficiently to alter the frequency distribution of power, not the total power level. Before synchronization effects are seen, the panel response to the turbulent boundary layer loading is discontinuously spatio-temporally correlated. The stability develops from different competing wavelengths; the spatial scale is significantly shorter than when forced with the superimposed external sound. When the external sound level decreases and the synchronized phases are lost, changes in the character of the spectra can be linked to the occurrence of spatial phase transition. These changes can develop broadband response. Synchronized responses of fuselage structure panels have been observed in subsonic and supersonic aircraft; results from two flights tests are discussed.

  8. Measurements of phase response in an oscillatory reaction and deduction of components of the adjoint eigenvector

    SciTech Connect

    Millett, I.; Vance, W.; Ross, J.

    1999-10-14

    The authors present the first experiments that use the phase response method to determine components of the adjoint eigenvector (of the Jacobian matrix of the linearized system) of an oscillating reaction system. The Briggs-Rauscher reaction was studied near a supercritical Hopf bifurcation. Phase response curves for I{sup {minus}} and Mn{sup 2+} have been determined, and from them corresponding components of the adjoint eigenvector have been deduced. The relative magnitudes and difference in arguments of these components agree reasonably well with those from a reduced model of the Briggs-Rauscher reaction, whereas agreement with results from quenching experiments is mixed.

  9. Intrinsic and Extrinsic Motivation among Collegiate Instrumentalists

    ERIC Educational Resources Information Center

    Diaz, Frank M.

    2010-01-01

    The purpose of this study was to gather and compare information on measures of intrinsic and extrinsic motivation among instrumentalists enrolled in collegiate ensembles. A survey instrument was developed to gather information concerning demographic data and responses to questions on motivational preference. Participants were undergraduate and…

  10. Responses of macaque ganglion cells to the relative phase of heterochromatically modulated lights.

    PubMed Central

    Smith, V C; Lee, B B; Pokorny, J; Martin, P R; Valberg, A

    1992-01-01

    1. We measured the response of macaque ganglion cells to sinusoidally modulated red and green lights as the relative phase, theta, of the lights was varied. 2. At low frequencies, red-green ganglion cells of the parvocellular (PC-) pathway with opponent inputs from middle-wavelength sensitive (M-) and long-wavelength sensitive (L-) cones were minimally sensitive to luminance modulation (theta = 0 deg) and maximally sensitive to chromatic modulation (theta = 180 deg). With increasing frequency, the phase, theta, of minimal amplitude gradually changed, in opposite directions for cells with M- and L-cone centres. 3. At high frequencies (at and above 20 Hz), phasic cells of the magnocellular (MC-) pathway were maximally responsive when theta approximately 0 deg and minimally responsive when theta approximately 180 deg, as expected from an achromatic mechanism. At lower frequencies, the phase of minimal response shifted, for both on- and off-centre cells, to values of theta intermediate between 0 and 180 deg. This phase asymmetry was absent if the centre alone was stimulated with a small field. 4. For PC-pathway cells, it was possible to provide an account of response phase as a function of theta, using a model involving three parameters; phases of the L- and M-cone mechanisms and a L/M cone weighting term. For red-green cells, the phase parameters were monotonically related to temporal frequency and revealed a centre-surround phase difference. The phase difference was linear with a slope of 1-3 deg Hz-1. If this represents a latency difference, it would be 3-8 ms. Otherwise, temporal properties of the M- and L-cones appeared similar if not identical. By addition of a scaling term, the model could be extended to give an adequate account of the amplitude of responses. 5. We were able to activate selectively the surrounds of cells with short-wavelength (S-) cone input to their centres, and so were able to assess L/M cone weighting to the surround. M- and L-cone inputs

  11. Hyperbaric Oxygen Treatment Induces a Two-Phase Antinociceptive Response of Unusually Long Duration in Mice

    PubMed Central

    Chung, Eunhee; Zelinski, Lisa M.; Ohgami, Yusuke; Shirachi, Donald Y.; Quock, Raymond M.

    2009-01-01

    Hyperbaric oxygen (HBO2) therapy is approved by the FDA for limited clinical indications but is reported to produce pain relief in several chronic pain conditions. However, there have been no studies to explain this apparent analgesic effect of HBO2. Research conducted in our laboratory demonstrates that four daily 60-min HBO2 treatments at 3.5 ATA induced an unparalleled antinociceptive response that consists of 1) an early phase that lasted at least six hours after the HBO2 treatment before dissipating; and 2) a late phase that emerged about 18 hours after the early phase and lasted for up to three weeks. The early phase was sensitive to antagonism by acutely intracerebroventricular (i.c.v.)-administered opioid antagonist naltrexone and the nitric oxide synthase (NOS)-inhibitor L-NAME. The late phase was inhibited by treatment with i.c.v. naltrexone or L-NAME during the four HBO2 treatments but was not antagonized by either naltrexone or L-NAME following acute pretreatment two weeks after HBO2 treatment. These experimental results implicate a novel mechanism that is activated by HBO2, resulting in an antinociceptive response of unusually long duration that is of potential interest in the clinical management of pain. Perspective Hyperbaric oxygen treatment of mice can induce a two-phase antinociceptive response of unusually long duration. Nitric oxide and opioid receptors appear to initiate or mediate both phases of the antinociceptive response. Further elucidation of the underlying mechanism may potentially identify molecular targets that cause long-lasting activation of endogenous analgesic systems. PMID:20418186

  12. Phase and period responses to short light pulses in a wild diurnal rodent, Funambulus pennanti.

    PubMed

    Kumar, Dhanananajay; Singaravel, Muniyandi

    2014-04-01

    Photic phase response curves (PRCs) have been extensively studied in many laboratory-bred diurnal and nocturnal rodents. However, comparatively fewer studies have addressed the effects of photic cues on wild diurnal mammals. Hence, we studied the effects of short durations of light pulses on the circadian systems of the diurnal Indian Palm squirrel, Funambulus pennanti. Adult males entrained to a light-dark cycle (12 h-12 h) were transferred to constant darkness (DD). Free-running animals were exposed to brief light pulses (250 lux) of 15 min, 3 circadian hours (CT) apart (CT 0, 3, 6, 9, 12, 15, 18 and 21). Phase shifts evoked at different phases were plotted against CT and a PRC was constructed. F. pennanti exhibited phase-dependent phase shifts at all the CTs studied, and the PRC obtained was of type 1 at the intensity of light used. Phase advances were evoked during the early subjective day and late subjective night, while phase delays occurred during the late subjective day and early subjective night, with maximum phase delay at CT 15 (-2.04 ± 0.23 h), and maximum phase advance at CT 21 (1.88 ± 0.31 h). No dead zone was seen at this resolution. The free-running period of the rhythm was concurrently lengthened (deceleration) during the late subjective day and early subjective night, while period shortening (acceleration) occurred during the late subjective night. The maximum deceleration was noticed at CT 15 (-0.40 ± 0.09 h) and the maximum acceleration at CT 21 (0.39 ± 0.07 h). A significant positive correlation exists between the phase shifts and the period changes (r = 0.684, p = 0.001). The shapes of both the PRC and period response curve (τRC) qualitatively resemble each other. This suggests that the palm squirrel's circadian system is entrained both by phase and period responses to light. Thus, F. pennanti exhibits robust clock-resetting in response to light pulses.

  13. Investigating the Temporal Patterns within and between Intrinsic Connectivity Networks under Eyes-Open and Eyes-Closed Resting States: A Dynamical Functional Connectivity Study Based on Phase Synchronization

    PubMed Central

    Wang, Xun-Heng; Li, Lihua; Xu, Tao; Ding, Zhongxiang

    2015-01-01

    The brain active patterns were organized differently under resting states of eyes open (EO) and eyes closed (EC). The altered voxel-wise and regional-wise resting state active patterns under EO/EC were found by static analysis. More importantly, dynamical spontaneous functional connectivity has been observed in the resting brain. To the best of our knowledge, the dynamical mechanisms of intrinsic connectivity networks (ICNs) under EO/EC remain largely unexplored. The goals of this paper were twofold: 1) investigating the dynamical intra-ICN and inter-ICN temporal patterns during resting state; 2) analyzing the altered dynamical temporal patterns of ICNs under EO/EC. To this end, a cohort of healthy subjects with scan conditions of EO/EC were recruited from 1000 Functional Connectomes Project. Through Hilbert transform, time-varying phase synchronization (PS) was applied to evaluate the inter-ICN synchrony. Meanwhile, time-varying amplitude was analyzed as dynamical intra-ICN temporal patterns. The results found six micro-states of inter-ICN synchrony. The medial visual network (MVN) showed decreased intra-ICN amplitude during EC relative to EO. The sensory-motor network (SMN) and auditory network (AN) exhibited enhanced intra-ICN amplitude during EC relative to EO. Altered inter-ICN PS was found between certain ICNs. Particularly, the SMN and AN exhibited enhanced PS to other ICNs during EC relative to EO. In addition, the intra-ICN amplitude might influence the inter-ICN synchrony. Moreover, default mode network (DMN) might play an important role in information processing during EO/EC. Together, the dynamical temporal patterns within and between ICNs were altered during different scan conditions of EO/EC. Overall, the dynamical intra-ICN and inter-ICN temporal patterns could benefit resting state fMRI-related research, and could be potential biomarkers for human functional connectome. PMID:26469182

  14. Optically addressed and submillisecond response phase only liquid crystal spatial light modulator

    NASA Astrophysics Data System (ADS)

    Zhao, Xiangjie; Duan, Jiazhu; Zhang, Dayong; Luo, Yongquan

    2014-10-01

    Liquid crystal based phase only spatial light modulator has attracted many research interests since last decades because of its superior advantage. Until now the liquid crystal spatial light modulator has been applied in many fields, but the response speed of nematic LC limited its further application. In this paper, an optically addressed phase only LC spatial light modulator was proposed based on polymer network liquid crystal. Morphology effect on the light scattering of PNLC was studied, which was mainly consisted of fiber and fiber bundles. The morphology nearly determined the light scattering and electro-optical property. Due to the high threshold voltage, to address the PNLC phase modulator was also concerned. Optical addressing method was proposed, in which BSO crystal was selected to replace one of the glass substrate. The response speed of PNLC was so fast that the reorientation of liquid crystal director will follow the change of effective voltage applied on LC layer, which was related with the voltage signal and especially with electron transport of photo-induced carriers due to diffusion and drift. The on state dynamic response of phase change was investigated. Based on this device, beam steering was also achieved by loading 488nm laser strip on the optical addressed phase only spatial light modulator.

  15. Stimulus-locked responses of two phase oscillators coupled with delayed feedback

    NASA Astrophysics Data System (ADS)

    Krachkovskyi, Valerii; Popovych, Oleksandr V.; Tass, Peter A.

    2006-06-01

    For a system of two phase oscillators coupled with delayed self-feedback we study the impact of pulsatile stimulation administered to both oscillators. This system models the dynamics of two coupled phase-locked loops (PLLs) with a finite internal delay within each loop. The delayed self-feedback leads to a rich variety of dynamical regimes, ranging from phase-locked and periodically modulated synchronized states to chaotic phase synchronization and desynchronization. Remarkably, for large coupling strength the two PLLs are completely desynchronized. We study stimulus-locked responses emerging in the different dynamical regimes. Simple phase resets may be followed by a response clustering, which is intimately connected with long poststimulus resynchronization. Intriguingly, a maximal perturbation (i.e., maximal response clustering and maximal resynchronization time) occurs, if the system gets trapped at a stable manifold of an unstable saddle fixed point due to appropriately calibrated stimulus. Also, single stimuli with suitable parameters can shift the system from a stable synchronized state to a stable desynchronized state or vice versa. Our result show that appropriately calibrated single pulse stimuli may cause pronounced transient and/or long-lasting changes of the oscillators’ dynamics. Pulse stimulation may, hence, constitute an effective approach for the control of coupled oscillators, which might be relevant to both physical and medical applications.

  16. Intrinsically Disordered Energy Landscapes

    NASA Astrophysics Data System (ADS)

    Chebaro, Yassmine; Ballard, Andrew J.; Chakraborty, Debayan; Wales, David J.

    2015-05-01

    Analysis of an intrinsically disordered protein (IDP) reveals an underlying multifunnel structure for the energy landscape. We suggest that such ‘intrinsically disordered’ landscapes, with a number of very different competing low-energy structures, are likely to characterise IDPs, and provide a useful way to address their properties. In particular, IDPs are present in many cellular protein interaction networks, and several questions arise regarding how they bind to partners. Are conformations resembling the bound structure selected for binding, or does further folding occur on binding the partner in a induced-fit fashion? We focus on the p53 upregulated modulator of apoptosis (PUMA) protein, which adopts an -helical conformation when bound to its partner, and is involved in the activation of apoptosis. Recent experimental evidence shows that folding is not necessary for binding, and supports an induced-fit mechanism. Using a variety of computational approaches we deduce the molecular mechanism behind the instability of the PUMA peptide as a helix in isolation. We find significant barriers between partially folded states and the helix. Our results show that the favoured conformations are molten-globule like, stabilised by charged and hydrophobic contacts, with structures resembling the bound state relatively unpopulated in equilibrium.

  17. Intrinsically disordered energy landscapes.

    PubMed

    Chebaro, Yassmine; Ballard, Andrew J; Chakraborty, Debayan; Wales, David J

    2015-01-01

    Analysis of an intrinsically disordered protein (IDP) reveals an underlying multifunnel structure for the energy landscape. We suggest that such 'intrinsically disordered' landscapes, with a number of very different competing low-energy structures, are likely to characterise IDPs, and provide a useful way to address their properties. In particular, IDPs are present in many cellular protein interaction networks, and several questions arise regarding how they bind to partners. Are conformations resembling the bound structure selected for binding, or does further folding occur on binding the partner in a induced-fit fashion? We focus on the p53 upregulated modulator of apoptosis (PUMA) protein, which adopts an α-helical conformation when bound to its partner, and is involved in the activation of apoptosis. Recent experimental evidence shows that folding is not necessary for binding, and supports an induced-fit mechanism. Using a variety of computational approaches we deduce the molecular mechanism behind the instability of the PUMA peptide as a helix in isolation. We find significant barriers between partially folded states and the helix. Our results show that the favoured conformations are molten-globule like, stabilised by charged and hydrophobic contacts, with structures resembling the bound state relatively unpopulated in equilibrium. PMID:25999294

  18. Elastin-like Polypeptides as Models of Intrinsically Disordered Proteins

    PubMed Central

    Roberts, Stefan; Dzuricky, Michael; Chilkoti, Ashutosh

    2015-01-01

    Elastin-like polypeptides (ELPs) are a class of stimuli-responsive biopolymers inspired by the intrinsically disordered domains of tropoelastin that are composed of repeats of the VPGXG pentapeptide motif, where X is a “guest residue”. They undergo a reversible, thermally triggered lower critical solution temperature (LCST) phase transition, which has been utilized for a variety of applications including protein purification, affinity capture, immunoassays, and drug delivery. ELPs have been extensively studied as protein polymers and as biomaterials, but their relationship to other disordered proteins has heretofore not been established. The biophysical properties of ELPs that lend them their unique material behavior are similar to the properties of many intrinsically disordered proteins (IDP). Their low sequence complexity, phase behavior, and elastic properties make them an interesting “minimal” artificial IDP, and the study of ELPs can hence provide insights into the behavior of other more complex IDPs. Motivated by this emerging realization of the similarities between ELPs and IDPs, this review discusses the biophysical properties of ELPs, their biomedical utility, and their relationship to other disordered polypeptide sequences. PMID:26325592

  19. In Utero Exposure to Lipopolysaccharide Alters the Postnatal Acute Phase Response in Beef Heifers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study was designed to determine the potential effect of prenatal lipopolysaccharide (LPS) exposure on the postnatal acute phase response (APR) to an LPS challenge in heifers. Pregnant crossbred cows (n = 50) were separated into prenatal immune stimulation (PIS; n = 25; administered 0.1 microgr...

  20. Altered postnatal acute phase response in heifers exposed to lipopolysachcharide in utero

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to determine the effect of prenatal lipopolysaccharide (LPS) exposure on the postnatal acute phase response (APR) to LPS challenge in heifer calves. Pregnant crossbred cows (n=50) were separated into prenatal stress (PNS; n=25; administered 0.1 microgram per kilogram...

  1. Modulation of the acute phase response in feedlot steers supplemented with Saccharomyces cerevisiae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study was designed to determine the effect of supplementing feedlot steers with Saccharomyces cerevisiae CNCM I-1079 (SC) on the acute phase response to a lipopolysaccharide (LPS) challenge. Steers (n = 18; 266 ± 4 kilograms body weight) were separated into three treatment groups (n = 6/treatm...

  2. Phase Response Synchronization in Neuronal Population with Time-Varying Coupling Strength

    PubMed Central

    Jiao, Xianfa; Zhao, Wanyu; Cao, Jinde

    2015-01-01

    We present the dynamic model of global coupled neuronal population subject to external stimulus by the use of phase sensitivity function. We investigate the effect of time-varying coupling strength on the synchronized phase response of neural population subjected to external harmonic stimulus. For a time-periodic coupling strength, we found that the stimulus with increasing intensity or frequency can reinforce the phase response synchronization in neuronal population of the weakly coupled neural oscillators, and the neuronal population with stronger coupling strength has good adaptability to stimulus. When we consider the dynamics of coupling strength, we found that a strong stimulus can quickly cause the synchronization in the neuronal population, the degree of synchronization grows with the increasing stimulus intensity, and the period of synchronized oscillation induced by external stimulation is related to stimulus frequency. PMID:26640514

  3. Intrinsic evolutions of dielectric function and electronic transition in tungsten doping Ge{sub 2}Sb{sub 2}Te{sub 5} phase change films discovered by ellipsometry at elevated temperatures

    SciTech Connect

    Guo, S.; Ding, X. J.; Zhang, J. Z.; Hu, Z. G. Chu, J. H.; Ji, X. L.; Wu, L. C.; Song, Z. T.

    2015-02-02

    Tungsten (W) doping effects on Ge{sub 2}Sb{sub 2}Te{sub 5} (GSTW) phase change films with different concentrations (3.2, 7.1, and 10.8%) have been investigated by variable-temperature spectroscopic ellipsometry. The dielectric functions from 210 K to 660 K have been evaluated with the aid of Tauc-Lorentz and Drude dispersion models. The analysis of Tauc gap energy (E{sub g}) and partial spectral weight integral reveal the correlation between optical properties and local structural change. The order degree increment and chemical bond change from covalent to resonant should be responsible for band gap narrowing and electronic transition enhancement during the phase change process. It is found that the elevated crystalline temperature for GSTW can be related to improved disorder degree. Furthermore, the shrinkage of E{sub g} for GSTW should be attributed to the enhanced metallicity compared with undoped GST.

  4. EGR Control for Emisson Reduction Using Fast Response Sensors - Phase 1A

    SciTech Connect

    Gravel, Roland; Conley, Jason; Kittelson, David

    2008-09-30

    The overall objective of this project was to develop exhaust gas recirculation (EGR) control strategies using fast-response Particulate Matter (PM) sensors and NOx sensors to improve the quality of particulate and gaseous emissions from diesel engines. This project initially comprised three phases: (1) Phase IA - sensor requirements to meet PM sensor specifications, NOx sensor assessment, and initial model development for EGR control; (2) Phase IB - continue development on PM and NOx sensors, integrate the sensor signals into the control simulations, and finalize model development for control strategies; and (3) Phase II - validation testing of the control strategies. Only Phase 1A was funded by DOE and executed by Honeywell. The major objectives of Phase 1A of the project included: (1) Sensor validation and operation of fast-response PM and NOx sensors; (2) Control system modeling of low-pressure EGR controls, development of control strategies, and initial evaluation of these models and strategies for EGR control in diesel engines; (3) Sensor testing to understand applicability of fast-response PM sensors in determining loading rates of the particle trap; and (4) Model validation and sensor testing under steady-state and transient operational conditions of actual engines. In particular, specific objectives included demonstration of: (1) A PM sensor response time constant (T10 - T90) of better than 100 milliseconds (msec); (2) The ability to detect PM at concentrations from 0.2 to 2 Bosch smoke number (BSN) or equivalent; (3) PM sensor accuracy to within 20% BSN over the entire range of operation; and (4) PM sensor repeatability to within 10% over the PM entire sensor range equivalent to a BSN of 0.2 to 2.

  5. Using Geo-Data Corporately on the Response Phase of Emergency Management

    NASA Astrophysics Data System (ADS)

    Demir Ozbek, E.; Ates, S.; Aydinoglu, A. C.

    2015-08-01

    Response phase of emergency management is the most complex phase in the entire cycle because it requires cooperation between various actors relating to emergency sectors. A variety of geo-data is needed at the emergency response such as; existing data provided by different institutions and dynamic data collected by different sectors at the time of the disaster. Disaster event is managed according to elaborately defined activity-actor-task-geodata cycle. In this concept, every activity of emergency response is determined with Standard Operation Procedure that enables users to understand their tasks and required data in any activity. In this study, a general conceptual approach for disaster and emergency management system is developed based on the regulations to serve applications in Istanbul Governorship Provincial Disaster and Emergency Directorate. The approach is implemented to industrial facility explosion example. In preparation phase, optimum ambulance locations are determined according to general response time of the ambulance to all injury cases in addition to areas that have industrial fire risk. Management of the industrial fire case is organized according to defined actors, activities, and working cycle that describe required geo-data. A response scenario was prepared and performed for an industrial facility explosion event to exercise effective working cycle of actors. This scenario provides using geo-data corporately between different actors while required data for each task is defined to manage the industrial facility explosion event. Following developing web technologies, this scenario based approach can be effective to use geo-data on the web corporately.

  6. Phase response curves of subthalamic neurons measured with synaptic input and current injection

    PubMed Central

    Wilson, Charles J.

    2012-01-01

    Infinitesimal phase response curves (iPRCs) provide a simple description of the response of repetitively firing neurons and may be used to predict responses to any pattern of synaptic input. Their simplicity makes them useful for understanding the dynamics of neurons when certain conditions are met. For example, the sizes of evoked phase shifts should scale linearly with stimulus strength, and the form of the iPRC should remain relatively constant as firing rate varies. We measured the PRCs of rat subthalamic neurons in brain slices using corticosubthalamic excitatory postsynaptic potentials (EPSPs; mediated by both AMPA- and NMDA-type receptors) and injected current pulses and used them to calculate the iPRC. These were relatively insensitive to both the size of the stimulus and the cell's firing rate, suggesting that the iPRC can predict the response of subthalamic nucleus cells to extrinsic inputs. However, the iPRC calculated using EPSPs differed from that obtained using current pulses. EPSPs (normalized for charge) were much more effective at altering the phase of subthalamic neurons than current pulses. The difference was not attributable to the extended time course of NMDA receptor-mediated currents, being unaffected by blockade of NMDA receptors. The iPRC provides a good description of subthalamic neurons' response to input, but iPRCs are best estimated using synaptic inputs rather than somatic current injection. PMID:22786957

  7. A three pulse phase response curve to three milligrams of melatonin in humans

    PubMed Central

    Burgess, Helen J; Revell, Victoria L; Eastman, Charmane I

    2008-01-01

    Exogenous melatonin is increasingly used for its phase shifting and soporific effects. We generated a three pulse phase response curve (PRC) to exogenous melatonin (3 mg) by administering it to free-running subjects. Young healthy subjects (n = 27) participated in two 5 day laboratory sessions, each preceded by at least a week of habitual, but fixed sleep. Each 5 day laboratory session started and ended with a phase assessment to measure the circadian rhythm of endogenous melatonin in dim light using 30 min saliva samples. In between were three days in an ultradian dim light (< 150 lux)–dark cycle (LD 2.5 : 1.5) during which each subject took one pill per day at the same clock time (3 mg melatonin or placebo, double blind, counterbalanced). Each individual's phase shift to exogenous melatonin was corrected by subtracting their phase shift to placebo (a free-run). The resulting PRC has a phase advance portion peaking about 5 h before the dim light melatonin onset, in the afternoon. The phase delay portion peaks about 11 h after the dim light melatonin onset, shortly after the usual time of morning awakening. A dead zone of minimal phase shifts occurred around the first half of habitual sleep. The fitted maximum advance and delay shifts were 1.8 h and 1.3 h, respectively. This new PRC will aid in determining the optimal time to administer exogenous melatonin to achieve desired phase shifts and demonstrates that using exogenous melatonin as a sleep aid at night has minimal phase shifting effects. PMID:18006583

  8. Temperature-responsive Solid-phase Extraction Column for Biological Sample Pretreatment.

    PubMed

    Akimaru, Michiko; Okubo, Kohei; Hiruta, Yuki; Kanazawa, Hideko

    2015-01-01

    We have developed a novel solid-phase extraction (SPE) system utilizing a temperature-responsive polymer hydrogel-modified stationary phase. Aminopropyl silica beads (average diameter, 40 - 64 μm) were coated with poly(N-isopropylacrylamide) (PNIPAAm)-based thermo-responsive hydrogels. Butyl methacrylate (BMA) and N,N-dimethylaminopropyl acrylamide (DMAPAAm) were used as the hydrophobic and cationic monomers, respectively, and copolymerized with NIPAAm. To evaluate the use of this SPE cartridge for the analysis of drugs and proteins in biological fluids, we studied the separation of phenytoin and theophylline from human serum albumin (HSA) as a model system. The retention of the analytes in an exclusively aqueous eluent could be modulated by changing the temperature and salt content. These results indicated that this temperature-responsive SPE system can be applied to the pretreatment of biological samples for the measurement of serum drug levels.

  9. Responses to selection on male-phase duration in Chamerion angustifolium.

    PubMed

    Routley, M B; Husband, B C

    2005-07-01

    Protandry (when male function precedes female) can enhance fitness by reducing selfing and increasing pollen export and outcrossed siring success. However, responses to selection on protandry may be constrained by genetic variation and correlations among floral traits. We examined these potential constraints in protandrous Chamerion angustifolium (Onagraceae) by estimating genetic variation in male-phase duration and associated floral traits using a paternal half-sib design and selection experiment. Narrow-sense heritability of male-phase duration was estimated as 0.23 (SE +/- 0.04) and was positively correlated with floral display. The selection experiment shortened male-phase duration 0.8 SD from the parental average of 17.0 h and lengthened it by 2.0 SD. Furthermore, fixed floral longevity caused a negative association between male- and female-phase durations. These results suggest that selection on male-phase duration is not limited by genetic variation. However, changes in male-phase duration may influence pollinators through correlated changes in floral display and reduced opportunities for pollen receipt during female phase. PMID:16033578

  10. A design of phase II cancer trials using total and complete response endpoints.

    PubMed

    Lu, Ying; Jin, Hua; Lamborn, Kathleen R

    2005-10-30

    Phase II clinical trials in oncology are used for initial evaluation of the therapeutic efficacy of a new treatment regimen. Simon's two-stage design based on total response (TR) rate is commonly used for such trials. Several authors have proposed alternative strategies to consider either response and toxicity or response and early progression. Because TR consists of both partial response (PR) and complete response (CR) and these two types of responses have different effects on subsequent patient outcome, Lin and Chen proposed a flexible design that is based on a weighted average of PR and CR rates as a way to recognize the differential significance of the two levels of response. Panageas and colleagues, on the other hand, used a trinomial model and direct search to consider a rejection region for PR and CR separately. In this paper, we reformat their hypotheses to assess efficacy based on TR and CR. A new two-stage optimum phase II trial design based on TR and CR is developed. We provide guides on searching the stopping and rejecting regions and on determining sample size. An example of a phase II trial for glioblastomas treatment is presented. In this trial, physicians would be interested in either stable disease (SD), PR, or CR as an indication of efficacy. However, because PR and CR rarely occur, observation of any PR or CR will lean towards acceptance of the treatment. Our design has the advantage of being close to the traditional Simon two-stage design while still having the flexibility to treat responses (PR and CR in this example) differently than SD.

  11. Intrinsically variable stars

    NASA Technical Reports Server (NTRS)

    Bohm-Vitense, Erika; Querci, Monique

    1987-01-01

    The characteristics of intrinsically variable stars are examined, reviewing the results of observations obtained with the IUE satellite since its launch in 1978. Selected data on both medium-spectral-class pulsating stars (Delta Cep stars, W Vir stars, and related groups) and late-type variables (M, S, and C giants and supergiants) are presented in spectra, graphs, and tables and described in detail. Topics addressed include the calibration of the the period-luminosity relation, Cepheid distance determination, checking stellar evolution theory by the giant companions of Cepheids, Cepheid masses, the importance of the hydrogen convection zone in Cepheids, temperature and abundance estimates for Population II pulsating stars, mass loss in Population II Cepheids, SWP and LWP images of cold giants and supergiants, temporal variations in the UV lines of cold stars, C-rich cold stars, and cold stars with highly ionized emission lines.

  12. Intrinsic anion oxidation potentials.

    PubMed

    Johansson, Patrik

    2006-11-01

    Anions of lithium battery salts have been investigated by electronic structure calculations with the objective to find a computational measure to correlate with the observed (in)stability of nonaqueous lithium battery electrolytes vs oxidation often encountered in practice. Accurate prediction of intrinsic anion oxidation potentials is here made possible by computing the vertical free energy difference between anion and neutral radical (Delta Gv) and further strengthened by an empirical correction using only the anion volume as a parameter. The 6-311+G(2df,p) basis set, the VSXC functional, and the C-PCM SCRF algorithm were used. The Delta Gv calculations can be performed using any standard computational chemistry software. PMID:17078600

  13. Intrinsic Feature Motion Tracking

    SciTech Connect

    Goddard, Jr., James S.

    2013-03-19

    Subject motion during 3D medical scanning can cause blurring and artifacts in the 3D images resulting in either rescans or poor diagnosis. Anesthesia or physical restraints may be used to eliminate motion but are undesirable and can affect results. This software measures the six degree of freedom 3D motion of the subject during the scan under a rigidity assumption using only the intrinsic features present on the subject area being monitored. This movement over time can then be used to correct the scan data removing the blur and artifacts. The software acquires images from external cameras or images stored on disk for processing. The images are from two or three calibrated cameras in a stereo arrangement. Algorithms extract and track the features over time and calculate position and orientation changes relative to an initial position. Output is the 3D position and orientation change measured at each image.

  14. Intrinsic Feature Motion Tracking

    2013-03-19

    Subject motion during 3D medical scanning can cause blurring and artifacts in the 3D images resulting in either rescans or poor diagnosis. Anesthesia or physical restraints may be used to eliminate motion but are undesirable and can affect results. This software measures the six degree of freedom 3D motion of the subject during the scan under a rigidity assumption using only the intrinsic features present on the subject area being monitored. This movement over timemore » can then be used to correct the scan data removing the blur and artifacts. The software acquires images from external cameras or images stored on disk for processing. The images are from two or three calibrated cameras in a stereo arrangement. Algorithms extract and track the features over time and calculate position and orientation changes relative to an initial position. Output is the 3D position and orientation change measured at each image.« less

  15. The acute phase response in parasite infection. Nippostrongylus brasiliensis in the mouse.

    PubMed Central

    Lamontagne, L R; Gauldie, J; Befus, A D; McAdam, K P; Baltz, M L; Pepys, M B

    1984-01-01

    Systemic inflammatory reactions are a prominent feature of many parasitic infections and the cellular and humoral components of the acute phase reaction may have an impact on the host-parasite relationship. We examined serum changes of four acute phase reactants: alpha 1-proteinase inhibition (alpha 1Pi); complement C3; serum amyloid A protein (SAA); and serum amyloid P component (SAP), in mice undergoing a primary infection with Nippostrongylus brasiliensis. SAA and SAP showed changes within the first 2 days of infection indicating the presence of an acute phase response associated with inflammation in the lung. Alpha 1Pi and C3 serum levels were not altered. However, all four acute phase reactants were synthesized in greater amounts by primary cultures of hepatocytes taken from infected animals at this time. Subsequently, as parasite-mediated inflammatory changes occur in the gut, both serum and hepatocyte cultures demonstrate an acute inflammatory response in all four reactants. It is proposed that the early reaction between parasites and macrophage/monocyte lead to the release of a mediator of inflammation which initiates the hepatocyte response. In this infection, at least one of the APR is shown to localize to the site of inflammation influencing the host-parasite relationship. Images Figure 2 Figure 3 PMID:6204934

  16. Evaluation of the accuracy of BOTDA systems based on the phase spectral response.

    PubMed

    Lopez-Gil, Alexia; Soto, Marcelo A; Angulo-Vinuesa, Xabier; Dominguez-Lopez, Alejandro; Martin-Lopez, Sonia; Thévenaz, Luc; Gonzalez-Herraez, Miguel

    2016-07-25

    We evaluate the Brillouin frequency shift (BFS) determination error when utilizing the Brillouin phase spectrum (BPS) instead of the Brillouin gain spectrum (BGS) in BOTDA systems. Systems based on the BPS perform the determination of the BFS through a linear fit around the zero de-phase frequency region. An analytical expression of the error obtained in the BFS determination as a function of the different experimental parameters is provided and experimentally validated. The experimental results show a good agreement with the theoretical predictions as a function of the number of sampling points, signal-to-noise ratio (SNR) and Brillouin spectral linewidth. For an equal SNR and linewidth, the phase response only provides a better BFS estimation than the gain response when the fit is performed over a restricted frequency range around the center of the spectral profile. This may reduce the measurement time of specific BOTDA systems requiring a narrow frequency scanning. When the frequency scan covers most of the Brillouin spectral profile, gain and phase responses give very similar estimations of the BFS and the BPS offers no crucial benefit.

  17. Liver genomic responses to ciguatoxin: evidence for activation of phase I and phase II detoxification pathways following an acute hypothermic response in mice.

    PubMed

    Morey, Jeanine S; Ryan, James C; Bottein Dechraoui, Marie-Yasmine; Rezvani, Amir H; Levin, Edward D; Gordon, Christopher J; Ramsdell, John S; Van Dolah, Frances M

    2008-06-01

    Ciguatoxins (CTX) are polyether neurotoxins that target voltage-gated sodium channels and are responsible for ciguatera, the most common fish-borne food poisoning in humans. This study characterizes the global transcriptional response of mouse liver to a symptomatic dose (0.26 ng/g) of the highly potent Pacific ciguatoxin-1 (P-CTX-1). At 1 h post-exposure 2.4% of features on a 44K whole genome array were differentially expressed (p < or = 0.0001), increasing to 5.2% at 4 h and decreasing to 1.4% by 24 h post-CTX exposure. Data were filtered (/fold change/ > or = 1.5 and p < or = 0.0001 in at least one time point) and a trend set of 1550 genes were used for further analysis. Early gene expression was likely influenced prominently by an acute 4 degrees C decline in core body temperature by 1 h, which resolved by 8 h following exposure. An initial downregulation of 32 different solute carriers, many involved in sodium transport, was observed. Differential gene expression in pathways involving eicosanoid biosynthesis and cholesterol homeostasis was also noted. Cytochrome P450s (Cyps) were of particular interest due to their role in xenobiotic metabolism. Twenty-seven genes, mostly members of Cyp2 and Cyp4 families, showed significant changes in expression. Many Cyps underwent an initial downregulation at 1 h but were quickly and strongly upregulated at 4 and 24 h post-exposure. In addition to Cyps, increases in several glutathione S-transferases were observed, an indication that both phase I and phase II metabolic reactions are involved in the hepatic response to CTX in mice. PMID:18353800

  18. Frequency and phase synchronization in neuromagnetic cortical responses to flickering-color stimuli

    NASA Astrophysics Data System (ADS)

    Timashev, S. F.; Polyakov, Yu. S.; Yulmetyev, R. M.; Demin, S. A.; Panischev, O. Yu.; Shimojo, S.; Bhattacharya, J.

    2010-03-01

    In our earlier study dealing with the analysis of neuromagnetic responses (magnetoencephalograms—MEG) to flickering-color stimuli for a group of control human subjects (9 volunteers) and a patient with photosensitive epilepsy (a 12-year old girl), it was shown that Flicker-Noise Spectroscopy (FNS) was able to identify specific differences in the responses of each organism. The high specificity of individual MEG responses manifested itself in the values of FNS parameters for both chaotic and resonant components of the original signal. The present study applies the FNS cross-correlation function to the analysis of correlations between the MEG responses simultaneously measured at spatially separated points of the human cortex processing the red-blue flickering color stimulus. It is shown that the cross-correlations for control (healthy) subjects are characterized by frequency and phase synchronization at different points of the cortex, with the dynamics of neuromagnetic responses being determined by the low-frequency processes that correspond to normal physiological rhythms. But for the patient, the frequency and phase synchronization breaks down, which is associated with the suppression of cortical regulatory functions when the flickering-color stimulus is applied, and higher frequencies start playing the dominating role. This suggests that the disruption of correlations in the MEG responses is the indicator of pathological changes leading to photosensitive epilepsy, which can be used for developing a method of diagnosing the disease based on the analysis with the FNS cross-correlation function.

  19. Visual stimuli recruit intrinsically generated cortical ensembles.

    PubMed

    Miller, Jae-eun Kang; Ayzenshtat, Inbal; Carrillo-Reid, Luis; Yuste, Rafael

    2014-09-23

    The cortical microcircuit is built with recurrent excitatory connections, and it has long been suggested that the purpose of this design is to enable intrinsically driven reverberating activity. To understand the dynamics of neocortical intrinsic activity better, we performed two-photon calcium imaging of populations of neurons from the primary visual cortex of awake mice during visual stimulation and spontaneous activity. In both conditions, cortical activity is dominated by coactive groups of neurons, forming ensembles whose activation cannot be explained by the independent firing properties of their contributing neurons, considered in isolation. Moreover, individual neurons flexibly join multiple ensembles, vastly expanding the encoding potential of the circuit. Intriguingly, the same coactive ensembles can repeat spontaneously and in response to visual stimuli, indicating that stimulus-evoked responses arise from activating these intrinsic building blocks. Although the spatial properties of stimulus-driven and spontaneous ensembles are similar, spontaneous ensembles are active at random intervals, whereas visually evoked ensembles are time-locked to stimuli. We conclude that neuronal ensembles, built by the coactivation of flexible groups of neurons, are emergent functional units of cortical activity and propose that visual stimuli recruit intrinsically generated ensembles to represent visual attributes. PMID:25201983

  20. Phase-locked responses to speech in human auditory cortex are enhanced during comprehension.

    PubMed

    Peelle, Jonathan E; Gross, Joachim; Davis, Matthew H

    2013-06-01

    A growing body of evidence shows that ongoing oscillations in auditory cortex modulate their phase to match the rhythm of temporally regular acoustic stimuli, increasing sensitivity to relevant environmental cues and improving detection accuracy. In the current study, we test the hypothesis that nonsensory information provided by linguistic content enhances phase-locked responses to intelligible speech in the human brain. Sixteen adults listened to meaningful sentences while we recorded neural activity using magnetoencephalography. Stimuli were processed using a noise-vocoding technique to vary intelligibility while keeping the temporal acoustic envelope consistent. We show that the acoustic envelopes of sentences contain most power between 4 and 7 Hz and that it is in this frequency band that phase locking between neural activity and envelopes is strongest. Bilateral oscillatory neural activity phase-locked to unintelligible speech, but this cerebro-acoustic phase locking was enhanced when speech was intelligible. This enhanced phase locking was left lateralized and localized to left temporal cortex. Together, our results demonstrate that entrainment to connected speech does not only depend on acoustic characteristics, but is also affected by listeners' ability to extract linguistic information. This suggests a biological framework for speech comprehension in which acoustic and linguistic cues reciprocally aid in stimulus prediction.

  1. Intrinsic Chevrolets at the SSC

    SciTech Connect

    Brodsky, S.J.; Collins, J.C.; Ellis, S.D.; Gunion, J.F.; Mueller, A.H.

    1984-01-01

    The possibility of the production at high energy of heavy quarks, supersymmetric particles and other large mass colored systems via the intrinsic twist-six components in the proton wave function is discussed. While the existing data do not rule out the possible relevance of intrinsic charm production at present energies, the extrapolation of such intrinsic contributions to very high masses and energies suggests that they will not play an important role at the SSC.

  2. Qutrit teleportation under intrinsic decoherence

    NASA Astrophysics Data System (ADS)

    Jafarpour, Mojtaba; Naderi, Negar

    2016-08-01

    We study qutrit teleportation and its fidelity in the presence and absence of intrinsic decoherence through a qutrit channel. The channel consists of a Heisenberg chain with xyz interaction model and the intrinsic decoherence is implemented through the Milburn model. It is shown that while the fidelity diminishes due to intrinsic decoherence, it may be enhanced if the channel is initially in an entangled state. It is also observed that, for stronger intrinsic decoherence, the initial entanglement of the channel is more effective in enhancing of fidelity.

  3. Lytic Gene Expression Is Frequent in HSV-1 Latent Infection and Correlates with the Engagement of a Cell-Intrinsic Transcriptional Response

    PubMed Central

    Ma, Joel Z.; Russell, Tiffany A.; Spelman, Tim

    2014-01-01

    Herpes simplex viruses (HSV) are significant human pathogens that provide one of the best-described examples of viral latency and reactivation. HSV latency occurs in sensory neurons, being characterized by the absence of virus replication and only fragmentary evidence of protein production. In mouse models, HSV latency is especially stable but the detection of some lytic gene transcription and the ongoing presence of activated immune cells in latent ganglia have been used to suggest that this state is not entirely quiescent. Alternatively, these findings can be interpreted as signs of a low, but constant level of abortive reactivation punctuating otherwise silent latency. Using single cell analysis of transcription in mouse dorsal root ganglia, we reveal that HSV-1 latency is highly dynamic in the majority of neurons. Specifically, transcription from areas of the HSV genome associated with at least one viral lytic gene occurs in nearly two thirds of latently-infected neurons and more than half of these have RNA from more than one lytic gene locus. Further, bioinformatics analyses of host transcription showed that progressive appearance of these lytic transcripts correlated with alterations in expression of cellular genes. These data show for the first time that transcription consistent with lytic gene expression is a frequent event, taking place in the majority of HSV latently-infected neurons. Furthermore, this transcription is of biological significance in that it influences host gene expression. We suggest that the maintenance of HSV latency involves an active host response to frequent viral activity. PMID:25058429

  4. Cell-intrinsic role for IFN-α–STAT1 signals in regulating murine Peyer patch plasmacytoid dendritic cells and conditioning an inflammatory response

    PubMed Central

    Li, Haiyan S.; Gelbard, Alexander; Martinez, Gustavo J.; Esashi, Eiji; Zhang, Huiyuan; Nguyen-Jackson, Hoainam; Liu, Yong-Jun; Overwijk, Willem W.

    2011-01-01

    Plasmacytoid dendritic cells (pDCs) reside in bone marrrow and lymphoid organs in homeostatic conditions and typically secrete abundant quantities of type I interferons (IFNs) on Toll-like receptor triggering. Recently, a pDC population was identified within Peyer patches (PPs) of the gut that is distinguished by its lack of IFN production; however, the relationship of PP pDCs to pDCs in other organs has been unclear. We report that PP pDCs are derived from common DC progenitors and accumulate in response to Fms-like tyrosine kinase 3 ligand, yet appear divergent in transcription factor profile and surface marker phenotype, including reduced E2-2 and CCR9 expression. Type I IFN signaling via STAT1 has a cell-autonomous role in accrual of PP pDCs in vivo. Moreover, IFN-α enhances pDC generation from DC progenitors by a STAT1-dependent mechanism. pDCs that have been developed in the presence of IFN-α resemble PP pDCs, produce inflammatory cytokines, stimulate Th17 cell generation, and fail to secrete IFN-α on Toll-like receptor engagement. These results indicate that IFN-α influences the development and function of pDCs by inducing emergence of an inflammatory (Th17-inducing) antigen-presenting subset, and simultaneously regulating accumulation of pDCs in the intestinal microenvironment. PMID:21828128

  5. Suggested response criteria for phase II antitumor drug studies for neurofibromatosis type 2 related vestibular schwannoma

    PubMed Central

    Plotkin, Scott R.; Halpin, Chris; Blakeley, Jaishri O.; Slattery, William H.; Welling, D. Bradley; Chang, Susan M.; Loeffler, Jay S.; Harris, Gordon J.; Sorensen, A. Gregory; McKenna, Michael J.

    2014-01-01

    Neurofibromatosis type 2 (NF2) is a tumor suppressor gene syndrome characterized by multiple schwannomas, especially vestibular schwannomas (VS), and meningiomas. Anticancer drug trials are now being explored, but there are no standardized endpoints in NF2. We review the challenges of NF2 clinical trials and suggest possible response criteria for use in initial phase II studies. We suggest two main response criteria in such trials. Objective radiographic response is defined as a durable 20% or greater reduction in VS volume based on postcontrast T1-weighted MRI images collected with 3 mm or finer cuts through the internal auditory canal. Hearing response is defined as a statistically significant improvement in word recognition scores using 50-word recorded lists in audiology. A possible composite endpoint incorporating both radiographic response and hearing response is outlined. We emphasize pitfalls in response assessment and suggest guidelines to minimize misinterpretations of response. We also identify research goals in NF2 to facilitate future trial conduct, such as identifying the expectations for time to tumor progression and time to measurable hearing loss in untreated NF2-related VS, and the relation of both endpoints to patient prognostic factors (such as age, baseline tumor volume, and measures of disease severity). These data would facilitate future use of endpoints based on stability of tumor size and hearing, which might be more appropriate for testing certain drugs. We encourage adoption of standardized endpoints early in the development of phase II trials for this population to facilitate comparison of results across trials of different agents. PMID:19430883

  6. Liver receptor homolog 1 is a negative regulator of the hepatic acute-phase response.

    PubMed

    Venteclef, Nicolas; Smith, Jason C; Goodwin, Bryan; Delerive, Philippe

    2006-09-01

    The orphan nuclear receptor liver receptor homolog 1 (LRH-1) has been reported to play an important role in bile acid biosynthesis and reverse cholesterol transport. Here, we show that LRH-1 is a key player in the control of the hepatic acute-phase response. Ectopic expression of LRH-1 with adenovirus resulted in strong inhibition of both interleukin-6 (IL-6)- and IL-1beta-stimulated haptoglobin, serum amyloid A, and fibrinogen beta gene expression in hepatocytes. Furthermore, induction of the hepatic inflammatory response was significantly exacerbated in HepG2 cells expressing short hairpin RNA targeting LRH-1 expression. Moreover, transient-transfection experiments and electrophoretic mobility shift and chromatin immunoprecipitation assays revealed that LRH-1 regulates this cytokine-elicited inflammatory response by, at least in part, antagonizing the CCAAT/enhancer binding protein beta signaling pathway. Finally, we show, by using LRH-1 heterozygous mice, that LRH-1 is involved in the control of the inflammatory response at the hepatic level in vivo. Taken together, our results outline an unexpected role for LRH-1 in the modulation of the hepatic acute-phase response.

  7. Undernutrition, the Acute Phase Response to Infection, and Its Effects on Micronutrient Status Indicators12

    PubMed Central

    Bresnahan, Kara A.; Tanumihardjo, Sherry A.

    2014-01-01

    Infection and undernutrition are prevalent in developing countries and demonstrate a synergistic relation. Undernutrition increases infection-related morbidity and mortality. The acute phase response (APR) is an innate, systemic inflammatory reaction to a wide array of disruptions in a host’s homeostasis, including infection. Released from immune cells in response to deleterious stimuli, proinflammatory cytokines act on distant tissues to induce behavioral (e.g., anorexia, weakness, and fatigue) and systemic effects of the APR. Cytokines act to increase energy and protein requirements to manifest fever and support hepatic acute phase protein (APP) production. Blood concentrations of glucose and lipid are augmented to provide energy to immune cells in response to cytokines. Additionally, infection decreases intestinal absorption of nutrients and can cause direct loss of micronutrients. Traditional indicators of iron, zinc, and vitamin A status are altered during the APR, leading to inaccurate estimations of deficiency in populations with a high or unknown prevalence of infection. Blood concentrations of APPs can be measured in nutrition interventions to assess the time stage and severity of infection and correct for the APR; however, standardized cutoffs for nutrition applications are needed. Protein-energy malnutrition leads to increased gut permeability to pathogens, abnormal immune cell populations, and impaired APP response. Micronutrient deficiencies cause specific immune impairments that affect both innate and adaptive responses. This review describes the antagonistic interaction between the APR and nutritional status and emphasizes the need for integrated interventions to address undernutrition and to reduce disease burden in developing countries. PMID:25398733

  8. Toward phase 4 trials in heart failure: A social and corporate responsibility of the medical profession.

    PubMed

    Iyngkaran, Pupalan; Beneby, Glen S

    2015-12-26

    Congestive heart failure (CHF) is a chronic condition, requiring polypharmacy, allied health supports and regular monitoring. All these factors are needed to ensure compliance and to deliver the positive outcomes demonstrated from randomized controlled trials. Unfortunately many centers around the world are unable to match trial level support. The outcomes for many communities are thus unclear. Research design factors in post-marketing surveillance to address this issue. Phase 4 studies is the name given to trials designed to obtain such community level data and thus address issues of external validity. CHF phase 4 studies are relatively underutilized. We feel the onus for this research lies with the health profession. In this commentary we provide arguments as to why phase 4 studies should be viewed as a social and corporate responsibility of health professional that care for clients with CHF.

  9. Melatonin shifts human circadian rhythms according to a phase-response curve.

    PubMed

    Lewy, A J; Ahmed, S; Jackson, J M; Sack, R L

    1992-10-01

    A physiological dose of orally administered melatonin shifts circadian rhythms in humans according to a phase-response curve (PRC) that is nearly opposite in phase with the PRCs for light exposure: melatonin delays circadian rhythms when administered in the morning and advances them when administered in the afternoon or early evening. The human melatonin PRC provides critical information for using melatonin to treat circadian phase sleep and mood disorders, as well as maladaptation to shift work and transmeridional air travel. The human melatonin PRC also provides the strongest evidence to date for a function of endogenous melatonin and its suppression by light in augmenting entrainment of circadian rhythms by the light-dark cycle. PMID:1394610

  10. Toward phase 4 trials in heart failure: A social and corporate responsibility of the medical profession

    PubMed Central

    Iyngkaran, Pupalan; Beneby, Glen S

    2015-01-01

    Congestive heart failure (CHF) is a chronic condition, requiring polypharmacy, allied health supports and regular monitoring. All these factors are needed to ensure compliance and to deliver the positive outcomes demonstrated from randomized controlled trials. Unfortunately many centers around the world are unable to match trial level support. The outcomes for many communities are thus unclear. Research design factors in post-marketing surveillance to address this issue. Phase 4 studies is the name given to trials designed to obtain such community level data and thus address issues of external validity. CHF phase 4 studies are relatively underutilized. We feel the onus for this research lies with the health profession. In this commentary we provide arguments as to why phase 4 studies should be viewed as a social and corporate responsibility of health professional that care for clients with CHF. PMID:26713277

  11. Toward phase 4 trials in heart failure: A social and corporate responsibility of the medical profession.

    PubMed

    Iyngkaran, Pupalan; Beneby, Glen S

    2015-12-26

    Congestive heart failure (CHF) is a chronic condition, requiring polypharmacy, allied health supports and regular monitoring. All these factors are needed to ensure compliance and to deliver the positive outcomes demonstrated from randomized controlled trials. Unfortunately many centers around the world are unable to match trial level support. The outcomes for many communities are thus unclear. Research design factors in post-marketing surveillance to address this issue. Phase 4 studies is the name given to trials designed to obtain such community level data and thus address issues of external validity. CHF phase 4 studies are relatively underutilized. We feel the onus for this research lies with the health profession. In this commentary we provide arguments as to why phase 4 studies should be viewed as a social and corporate responsibility of health professional that care for clients with CHF. PMID:26713277

  12. Simulated response of top-hat electrostatic analysers - importance of phase-space resolution

    NASA Astrophysics Data System (ADS)

    De Marco, Rossana; Bruno, Roberto; D'Amicis, Raffaella; Federica Marcucci, Maria; Servidio, Sergio; Valentini, Francesco

    2016-04-01

    We use a numerical code able to reproduce the angular/energy response of a typical electrostatic analyzer of top-hat type starting from velocity distribution functions (VDFs) generated by numerical imulations.The simulations are based on the Hybrid Vlasov-Maxwell (HVM) numerical algorithm which integrates the Vlasov equation for the ion distribution function in multi-dimensional geometry in phase space, while the electrons are treated as a fluid. Virtual satellites launched through the simulation box measure the particle VDFs. Such VDFs are interpolated into a spacecraft reference frame and moved from the simulation Cartesian grid to energy-angular coordinates to mimic the response of a real electrostatic sensor in the solar wind and in the magnetosheath for different conditions. We discuss the results of this study with respect to the importance of phase-space resolution for a space plasma experiment meant to investigate kinetic plasma regime.

  13. Human phase response curve to a 1 h pulse of bright white light

    PubMed Central

    St Hilaire, Melissa A; Gooley, Joshua J; Khalsa, Sat Bir S; Kronauer, Richard E; Czeisler, Charles A; Lockley, Steven W

    2012-01-01

    The phase resetting response of the human circadian pacemaker to light depends on the timing of exposure and is described by a phase response curve (PRC). The current study aimed to construct a PRC for a 1 h exposure to bright white light (∼8000 lux) and to compare this PRC to a <3 lux dim background light PRC. These data were also compared to a previously completed 6.7 h bright white light PRC and a <15 lux dim background light PRC constructed under similar conditions. Participants were randomized for exposure to 1 h of either bright white light (n= 18) or <3 lux dim background light (n= 18) scheduled at 1 of 18 circadian phases. Participants completed constant routine (CR) procedures in dim light (<3 lux) before and after the light exposure to assess circadian phase. Phase shifts were calculated as the difference in timing of dim light melatonin onset (DLMO) during pre- and post-stimulus CRs. Exposure to 1 h of bright white light induced a Type 1 PRC with a fitted peak-to-trough amplitude of 2.20 h. No discernible PRC was observed in the <3 lux dim background light PRC. The fitted peak-to-trough amplitude of the 1 h bright light PRC was ∼40% of that for the 6.7 h PRC despite representing only 15% of the light exposure duration, consistent with previous studies showing a non-linear duration–response function for the effects of light on circadian resetting. PMID:22547633

  14. Physiological and behavioral responses to an acute-phase response in zebra finches: immediate and short-term effects.

    PubMed

    Sköld-Chiriac, Sandra; Nord, Andreas; Nilsson, Jan-Åke; Hasselquist, Dennis

    2014-01-01

    Activation of the immune system to clear pathogens and mitigate infection is a costly process that might incur fitness costs. When vertebrates are exposed to pathogens, their first line of defense is the acute-phase response (APR), which consists of a suite of physiological and behavioral changes. The dynamics of the APR are relatively well investigated in mammals and domesticated birds but still rather unexplored in passerine birds. In this study, we injected male zebra finches (Taeniopygia guttata) with a bacterial endotoxin (lipopolysaccharide [LPS]) to assess the potential physiological, immunological, and behavioral responses during the time course of an APR and also to record any potential short-term effects by measuring the birds during the days after the expected APR. We found that LPS-injected zebra finches decreased activity and gained less body mass during the APR, compared to control individuals. In addition, LPS-injected birds increased their production of LPS-reactive antibodies and reduced their metabolic rate during the days after the expected APR. Our results show that zebra finches demonstrate sickness behaviors during an APR but also that physiological effects persist after the expected time course of an APR. These delayed effects might be either a natural part of the progression of an APR, which is probably true for the antibody response, or a short-term carryover effect, which is probably true for the metabolic response.

  15. Modeling the viscoplastic micromechanical response of two-phase materials using fast Fourier transforms

    SciTech Connect

    Lebensohn, Ricardo A; Lee, Sukbin; Rollett, Anthony D

    2009-01-01

    A viscoplastic approach using the Fast Fourier Transform (FFT) method for obtaining local mechanical response is utilized to study microstructure-property relationships in composite materials. Specifically, three-dimensional, two-phase digital materials containing isotropically coarsened particles surrounded by a matrix phase, generated through a Kinetic Monte Carlo Potts model for Ostwald ripening, are used as instantiations in order to calculate the stress and strain rate fields under uniaxial tension. The effects of the morphology of the matrix phase, the volume fraction and the contiguity of particles, and the polycrystallinity of matrix phase, on the stress and strain rate fields under uniaxial tension are examined. It is found that the first moments of the stress and strain rate fields have a different dependence on the particle volume fraction and the particle contiguity from their second moments. The average stresses and average strain rates of both phases and of the overall composite have rather simple relationships with the particle volume fraction whereas their standard deviations vary strongly, especially when the particle volume fraction is high, and the contiguity of particles has a noticeable effect on the mechanical response. It is also found that the shape of stress distribution in the BCC hard particle phase evolves as the volume fraction of particles in the composite varies, such that it agrees with the stress field in the BCC polycrystal as the volume of particles approaches unity. Finally, it is observed that the stress and strain rate fields in the microstructures with a polycrystalline matrix are less sensitive to changes in volume fraction and contiguity of particles.

  16. Sex differences in acute hormonal and subjective response to naltrexone: the impact of menstrual cycle phase

    PubMed Central

    Roche, Daniel J.O.; King, Andrea C.

    2015-01-01

    Women often exhibit larger hormonal and subjective responses to opioid receptor antagonists than men, but the biological mechanisms mediating this effect remain unclear. Among women, fluctuations in estradiol (E2) and progesterone (P4) across the menstrual cycle (MC) affect the endogenous opioid system. Therefore, the goal of the current study was to compare acute naltrexone response between women in the early follicular phase of the MC (low E2 and P4), women in the luteal phase of the MC (high E2 and P4), and men. Seventy healthy controls (n = 46 women) participated in two morning sessions in which they received 50 mg naltrexone or placebo in a randomized, counterbalanced order. Women were randomized to complete both sessions in either the early follicular (n = 23) or luteal phase of the MC. Serum cortisol, prolactin, and luteinizing hormone (LH), salivary cortisol, and subjective response were assessed upon arrival to the laboratory and at regular intervals after pill administration. In luteal and early follicular women but not men, naltrexone (vs. placebo) increased serum cortisol and prolactin levels from baseline; however, the naltrexone-induced increases in these hormones were significantly greater in luteal women than early follicular women. Additionally, only luteal women demonstrated an increase from baseline in salivary cortisol levels and the severity of adverse drug effects in response to naltrexone. In sum, the results indicate that luteal phase women are more sensitive to acute hormonal and subjective effects of naltrexone than early follicular women and men. These findings may have important implications for the use of naltrexone in women. PMID:25459893

  17. Nonlinear driven response of a phase-field crystal in a periodic pinning potential.

    PubMed

    Achim, C V; Ramos, J A P; Karttunen, M; Elder, K R; Granato, E; Ala-Nissila, T; Ying, S C

    2009-01-01

    We study numerically the phase diagram and the response under a driving force of the phase field crystal model for pinned lattice systems introduced recently for both one- and two-dimensional systems. The model describes the lattice system as a continuous density field in the presence of a periodic pinning potential, allowing for both elastic and plastic deformations of the lattice. We first present results for phase diagrams of the model in the absence of a driving force. The nonlinear response to a driving force on an initially pinned commensurate phase is then studied via overdamped dynamic equations of motion for different values of mismatch and pinning strengths. For large pinning strength the driven depinning transitions are continuous, and the sliding velocity varies with the force from the threshold with power-law exponents in agreement with analytical predictions. Transverse depinning transitions in the moving state are also found in two dimensions. Surprisingly, for sufficiently weak pinning potential we find a discontinuous depinning transition with hysteresis even in one dimension under overdamped dynamics. We also characterize structural changes of the system in some detail close to the depinning transition.

  18. Hydration-Responsive Folding and Unfolding in Graphene Oxide Liquid Crystal Phases

    PubMed Central

    Guo, Fei; Kim, Franklin; Han, Tae Hee; Shenoy, Vivek B.; Huang, Jiaxing; Hurt, Robert H.

    2011-01-01

    Graphene oxide is promising as a plate-like giant molecular building block for the assembly of new carbon materials. Its water dispersibility, liquid crystallinity, and ease of reduction offer advantages over other carbon precursors if its fundamental assembly rules can be identified. This article shows that graphene oxide sheets of known lateral dimension form nematic liquid crystal phases with transition points in agreement with the Onsager hard-plate theory. The liquid crystal phases can be systematic ordered into defined supramolecular patterns using surface anchoring, complex fluid flow, and micro-confinement. Graphene oxide is seen to exhibit homeotropic surface anchoring at interfaces driven by excluded volume entropy and by adsorption enthalpy associated with its partially hydrophobic basal planes. Surprisingly, some of the surface-ordered graphene oxide phases dry into graphene oxide solids that undergo a dramatic anisotropic swelling upon rehydration to recover their initial size and shape. This behavior is shown to be a unique hydration-responsive folding and unfolding transition. During drying, surface tension forces acting parallel to the layer planes cause a buckling instability that stores elastic energy in accordion-folded structures in the dry solid. Subsequent water infiltration reduces interlayer frictional forces and triggers release of the stored elastic energy in the form of dramatic unidirectional expansion. We explain the folding/unfolding phenomena by quantitative nanomechanics, and introduce the potential of liquid crystal-derived graphene oxide phases as new stimuli-response materials. PMID:21877716

  19. An extended mathematical model for reproducing the phase response of Arabidopsis thaliana under various light conditions.

    PubMed

    Ohara, Takayuki; Fukuda, Hirokazu; Tokuda, Isao T

    2015-10-01

    Experimental studies showed that light qualities such as color and strength influence the phase response properties of plant circadian systems. These effects, however, have yet to be properly addressed in theoretical models of plant circadian systems. To fill this gap, the present paper develops a mathematical model of a plant circadian clock that takes into account the intensity and wavelength of the input light. Based on experimental knowledge, we model three photoreceptors, Phytochrome A, Phytochrome B, and Cryptochrome 1, which respond to red and/or blue light, in Arabidopsis thaliana. The three photoreceptors are incorporated into a standard mathematical model of the plant system, in which activator and repressor genes form a single feedback loop. The model capability is examined by a phase response curve (PRC), which plots the phase shifts elicited by the light perturbation as a function of the perturbation phase. Numerical experiments demonstrate that the extended model reproduces the essential features of the PRCs measured experimentally under various light conditions. Particularly, unlike conventional models, the model generates the inherent shape of the PRC under dark pulse stimuli. The outcome of our modeling approach may motivate future theoretical and experimental studies of plant circadian rhythms.

  20. Visualizing phase transition behavior of dilute stimuli responsive polymer solutions via Mueller matrix polarimetry.

    PubMed

    Narayanan, Amal; Chandel, Shubham; Ghosh, Nirmalya; De, Priyadarsi

    2015-09-15

    Probing volume phase transition behavior of superdiluted polymer solutions both micro- and macroscopically still persists as an outstanding challenge. In this regard, we have explored 4 × 4 spectral Mueller matrix measurement and its inverse analysis for excavating the microarchitectural facts about stimuli responsiveness of "smart" polymers. Phase separation behavior of thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) and pH responsive poly(N,N-(dimethylamino)ethyl methacrylate) (PDMAEMA) and their copolymers were analyzed in terms of Mueller matrix derived polarization parameters, namely, depolarization (Δ), diattenuation (d), and linear retardance (δ). The Δ, d, and δ parameters provided useful information on both macro- and microstructural alterations during the phase separation. Additionally, the two step action ((i) breakage of polymer-water hydrogen bonding and (ii) polymer-polymer aggregation) at the molecular microenvironment during the cloud point generation was successfully probed via these parameters. It is demonstrated that, in comparison to the present techniques available for assessing the hydrophobic-hydrophilic switch over of simple stimuli-responsive polymers, Mueller matrix polarimetry offers an important advantage requiring a few hundred times dilute polymer solution (0.01 mg/mL, 1.1-1.4 μM) at a low-volume format. PMID:26287499

  1. The Elicitation of Audiovisual Steady-State Responses: Multi-Sensory Signal Congruity and Phase Effects

    PubMed Central

    Rhone, Ariane E.; Idsardi, William J.; Simon, Jonathan Z.; Poeppel, David

    2013-01-01

    Most ecologically natural sensory inputs are not limited to a single modality. While it is possible to use real ecological materials as experimental stimuli to investigate the neural basis of multi-sensory experience, parametric control of such tokens is limited. By using artificial bimodal stimuli composed of approximations to ecological signals, we aim to observe the interactions between putatively relevant stimulus attributes. Here we use MEG as an electrophysiological tool and employ as a measure the steady-state response (SSR), an experimental paradigm typically applied to unimodal signals. In this experiment we quantify the responses to a bimodal audio-visual signal with different degrees of temporal (phase) congruity, focusing on stimulus properties critical to audiovisual speech. An amplitude modulated auditory signal (‘pseudo-speech’) is paired with a radius-modulated ellipse (‘pseudo-mouth’), with the envelope of low-frequency modulations occurring in phase or at offset phase values across modalities. We observe (i) that it is possible to elicit an SSR to bimodal signals; (ii) that bimodal signals exhibit greater response power than unimodal signals; and (iii) that the SSR power at specific harmonics and sensors differentially reflects the congruity between signal components. Importantly, we argue that effects found at the modulation frequency and second harmonic reflect differential aspects of neural coding of multisensory signals. The experimental paradigm facilitates a quantitative characterization of properties of multi-sensory speech and other bimodal computations. PMID:21380858

  2. Phase Response Design of Recursive All-Pass Digital Filters Using a Modified PSO Algorithm

    PubMed Central

    Chang, Wei-Der

    2015-01-01

    This paper develops a new design scheme for the phase response of an all-pass recursive digital filter. A variant of particle swarm optimization (PSO) algorithm will be utilized for solving this kind of filter design problem. It is here called the modified PSO (MPSO) algorithm in which another adjusting factor is more introduced in the velocity updating formula of the algorithm in order to improve the searching ability. In the proposed method, all of the designed filter coefficients are firstly collected to be a parameter vector and this vector is regarded as a particle of the algorithm. The MPSO with a modified velocity formula will force all particles into moving toward the optimal or near optimal solution by minimizing some defined objective function of the optimization problem. To show the effectiveness of the proposed method, two different kinds of linear phase response design examples are illustrated and the general PSO algorithm is compared as well. The obtained results show that the MPSO is superior to the general PSO for the phase response design of digital recursive all-pass filter. PMID:26366168

  3. Orientation-Cue Invariant Population Responses to Contrast-Modulated and Phase-Reversed Contour Stimuli in Macaque V1 and V2

    PubMed Central

    An, Xu; Gong, Hongliang; Yin, Jiapeng; Wang, Xiaochun; Pan, Yanxia; Zhang, Xian; Lu, Yiliang; Yang, Yupeng; Toth, Zoltan; Schiessl, Ingo; McLoughlin, Niall; Wang, Wei

    2014-01-01

    Visual scenes can be readily decomposed into a variety of oriented components, the processing of which is vital for object segregation and recognition. In primate V1 and V2, most neurons have small spatio-temporal receptive fields responding selectively to oriented luminance contours (first order), while only a subgroup of neurons signal non-luminance defined contours (second order). So how is the orientation of second-order contours represented at the population level in macaque V1 and V2? Here we compared the population responses in macaque V1 and V2 to two types of second-order contour stimuli generated either by modulation of contrast or phase reversal with those to first-order contour stimuli. Using intrinsic signal optical imaging, we found that the orientation of second-order contour stimuli was represented invariantly in the orientation columns of both macaque V1 and V2. A physiologically constrained spatio-temporal energy model of V1 and V2 neuronal populations could reproduce all the recorded population responses. These findings suggest that, at the population level, the primate early visual system processes the orientation of second-order contours initially through a linear spatio-temporal filter mechanism. Our results of population responses to different second-order contour stimuli support the idea that the orientation maps in primate V1 and V2 can be described as a spatial-temporal energy map. PMID:25188576

  4. Flight performance of western sandpipers, Calidris mauri, remains uncompromised when mounting an acute phase immune response.

    PubMed

    Nebel, Silke; Buehler, Deborah M; MacMillan, Alexander; Guglielmo, Christopher G

    2013-07-15

    Migratory birds have been implicated in the spread of some zoonotic diseases, but how well infected individuals can fly remains poorly understood. We used western sandpipers, Calidris mauri, to experimentally test whether flight is affected when long-distance migrants are mounting an immune response and whether migrants maintain immune defences during a flight in a wind tunnel. We measured five indicators of innate immunity in 'flown-healthy' birds (flying in a wind tunnel without mounting an immune response), 'flown-sick' birds (flying while mounting an acute phase response, which is part of induced innate immunity), and a non-flying control group ('not-flown'). Voluntary flight duration did not differ between flown-healthy and flown-sick birds, indicating that mounting an acute phase response to simulated infection did not hamper an individual's ability to fly for up to 3 h. However, in comparison to not-flown birds, bacterial killing ability of plasma was significantly reduced after flight in flown-sick birds. In flown-healthy birds, voluntary flight duration was positively correlated with bacterial killing ability and baseline haptoglobin concentration of the blood plasma measured 1-3 weeks before experimental flights, suggesting that high quality birds had strong immune systems and greater flight capacity. Our findings indicate that flight performance is not diminished by prior immune challenge, but that flight while mounting an acute phase response negatively affects other aspects of immune function. These findings have important implications for our understanding of the transmission of avian diseases, as they suggest that birds can still migrate while fighting an infection.

  5. Intrinsic Angular Momentum of Light.

    ERIC Educational Resources Information Center

    Santarelli, Vincent

    1979-01-01

    Derives a familiar torque-angular momentum theorem for the electromagnetic field, and includes the intrinsic torques exerted by the fields on the polarized medium. This inclusion leads to the expressions for the intrinsic angular momentum carried by the radiation traveling through a charge-free medium. (Author/MA)

  6. Menstrual cycle phase effects free testosterone responses to prolonged aerobic exercise.

    PubMed

    Lane, A R; O'Leary, C B; Hackney, A C

    2015-09-01

    Research has shown that total testosterone (tT) levels in women increase acutely during a prolonged bout of aerobic exercise. Few studies, however, have considered the impact of the menstrual cycle phase on this response or have looked at the biologically active free testosterone (fT) form responses. Therefore, this study examined the fT concentration response independently and as a percentage (fT%) of tT to prolonged aerobic exercise during phases of the menstrual cycle with low estrogen-progesterone (L-EP; i.e., follicular phase) and high estrogen-progesterone (H-EP; i.e., luteal phase). Ten healthy, recreationally trained, eumennorrheic women (X ± SD: age = 20 ± 2 y, mass = 58.7 ± 8.3 kg, body fat = 22.3 ± 4.9 %, VO(2max) = 50.7 ± 9.0 ml/kg/min) participated in a laboratory based study and completed a 60-minute treadmill run during the L-EP and H-EP menstrual phases at ~70% of VO(2max). Blood was drawn prior to (PRE), immediately after (POST) and following 30 minutes of recovery (30POST) with each 60-minute run. During H-EP, there was a significant increase in fT concentrations from PRE to POST (p < 0.01) while in L-EP fT levels were unchanged; which resulted in fT being significantly higher at H-EP POST versus L-EP POST (p < 0.03). Area-under-the-curve (AUC) responses were calculated, for fT the total AUC was greater in H-EP than L-EP (p < 0.04). There was no significant interaction of fT% between phases and exercise sampling time. There was, however, a main effect for exercise where fT% POST was a greater proportion of tT than at PRE (p < 0.01). In summary, hormonal changes associated with the menstrual cycle impact fT response to a prolonged aerobic exercise bout; specifically, there being higher levels under H-EP conditions. This suggests more biologically active T is available during exercise in this phase. This response may be a function of the higher core temperatures found with H-EP causing greater sex hormone binding protein release of T, or could

  7. Menstrual cycle phase effects free testosterone responses to prolonged aerobic exercise.

    PubMed

    Lane, A R; O'Leary, C B; Hackney, A C

    2015-09-01

    Research has shown that total testosterone (tT) levels in women increase acutely during a prolonged bout of aerobic exercise. Few studies, however, have considered the impact of the menstrual cycle phase on this response or have looked at the biologically active free testosterone (fT) form responses. Therefore, this study examined the fT concentration response independently and as a percentage (fT%) of tT to prolonged aerobic exercise during phases of the menstrual cycle with low estrogen-progesterone (L-EP; i.e., follicular phase) and high estrogen-progesterone (H-EP; i.e., luteal phase). Ten healthy, recreationally trained, eumennorrheic women (X ± SD: age = 20 ± 2 y, mass = 58.7 ± 8.3 kg, body fat = 22.3 ± 4.9 %, VO(2max) = 50.7 ± 9.0 ml/kg/min) participated in a laboratory based study and completed a 60-minute treadmill run during the L-EP and H-EP menstrual phases at ~70% of VO(2max). Blood was drawn prior to (PRE), immediately after (POST) and following 30 minutes of recovery (30POST) with each 60-minute run. During H-EP, there was a significant increase in fT concentrations from PRE to POST (p < 0.01) while in L-EP fT levels were unchanged; which resulted in fT being significantly higher at H-EP POST versus L-EP POST (p < 0.03). Area-under-the-curve (AUC) responses were calculated, for fT the total AUC was greater in H-EP than L-EP (p < 0.04). There was no significant interaction of fT% between phases and exercise sampling time. There was, however, a main effect for exercise where fT% POST was a greater proportion of tT than at PRE (p < 0.01). In summary, hormonal changes associated with the menstrual cycle impact fT response to a prolonged aerobic exercise bout; specifically, there being higher levels under H-EP conditions. This suggests more biologically active T is available during exercise in this phase. This response may be a function of the higher core temperatures found with H-EP causing greater sex hormone binding protein release of T, or could

  8. Phase-dependent response of the lung to NO sub 2 irritant insult

    SciTech Connect

    Siegel, P.D.; Bozelka, B.E.; Reynolds, C.; George, W.J. )

    1989-07-01

    The biochemical and histopathological response of the lung following acute and repeated (subacute) exposure to nitrogen oxide (NO{sub 2}) was examined. Activities of lactate dehydrogenase, beta-glucuronidase, choline kinase, and protease inhibitor were measured in murine pulmonary tissue immediately and two days following exposure. Nonenzymatic parameters, pulmonary protein content, and wet lung weight were also monitored. Immediately following acute exposure to NO{sub 2}, only the nonenzymatic parameters were elevated. By two days following acute exposure, following subacute exposure; however, the nonenzymatic parameters were attenuated with respect to the enzymatic activities. The lung exhibits a dynamic response following damage by oxidants such as NO{sub 2}. This response is divided into three distinct phases (exudative, proliferative, and tolerant), which can be characterized both biochemically and histopathologically.

  9. The Role of Plasma Membrane Intrinsic Protein Aquaporins in Water Transport through Roots: Diurnal and Drought Stress Responses Reveal Different Strategies between Isohydric and Anisohydric Cultivars of Grapevine1[OA

    PubMed Central

    Vandeleur, Rebecca K.; Mayo, Gwenda; Shelden, Megan C.; Gilliham, Matthew; Kaiser, Brent N.; Tyerman, Stephen D.

    2009-01-01

    We report physiological and anatomical characteristics of water transport across roots grown in soil of two cultivars of grapevine (Vitis vinifera) differing in response to water stress (Grenache, isohydric; Chardonnay, anisohydric). Both cultivars have similar root hydraulic conductances (Lo; normalized to root dry weight) that change diurnally. There is a positive correlation between Lo and transpiration. Under water stress, both cultivars have reduced minimum daily Lo (predawn) attributed to the development of apoplastic barriers. Water-stressed and well-watered Chardonnay had the same diurnal change in amplitude of Lo, while water-stressed Grenache showed a reduction in daily amplitude compared with well-watered plants. Hydraulic conductivity of root cortex cells (Lpcell) doubles in Chardonnay but remains unchanged in Grenache. Of the two most highly expressed plasma membrane intrinsic protein (PIP) aquaporins in roots (VvPIP1;1 and VvPIP2;2), only VvPIP2;2 functions as a water channel in Xenopus laevis oocytes. VvPIP1;1 interacts with VvPIP2;2 to induce 3-fold higher water permeability. These two aquaporins are colocated in the root from in situ hybridization and immunolocalization of VvPIP1 and VvPIP2 subfamily members. They occur in root tip, exodermis, root cortex (detected up to 30 mm), and stele. VvPIP2;2 mRNA does not change diurnally or with water stress, in contrast to VvPIP1;1, in which expression reflects the differences in Lo and Lpcell between cultivars in their responses to water stress and rewatering. VvPIP1;1 may regulate water transport across roots such that transpirational demand is matched by root water transport capacity. This occurs on a diurnal basis and in response to water stress that corresponds to the difference in drought tolerance between the cultivars. PMID:18987216

  10. Extrinsic and intrinsic curvatures in thermodynamic geometry

    NASA Astrophysics Data System (ADS)

    Hosseini Mansoori, Seyed Ali; Mirza, Behrouz; Sharifian, Elham

    2016-08-01

    We investigate the intrinsic and extrinsic curvatures of a certain hypersurface in thermodynamic geometry of a physical system and show that they contain useful thermodynamic information. For an anti-Reissner-Nordström-(A)de Sitter black hole (Phantom), the extrinsic curvature of a constant Q hypersurface has the same sign as the heat capacity around the phase transition points. The intrinsic curvature of the hypersurface can also be divergent at the critical points but has no information about the sign of the heat capacity. Our study explains the consistent relationship holding between the thermodynamic geometry of the KN-AdS black holes and those of the RN (J-zero hypersurface) and Kerr black holes (Q-zero hypersurface) ones [1]. This approach can easily be generalized to an arbitrary thermodynamic system.

  11. SnTe field effect transistors and the anomalous electrical response of structural phase transition

    SciTech Connect

    Li, Haitao Zhu, Hao; Yuan, Hui; Li, Qiliang; You, Lin; Kopanski, Joseph J.; Richter, Curt A.; Zhao, Erhai

    2014-07-07

    SnTe is a conventional thermoelectric material and has been newly found to be a topological crystalline insulator. In this work, back-gate SnTe field-effect transistors have been fabricated and fully characterized. The devices exhibit n-type transistor behaviors with excellent current-voltage characteristics and large on/off ratio (>10{sup 6}). The device threshold voltage, conductance, mobility, and subthreshold swing have been studied and compared at different temperatures. It is found that the subthreshold swings as a function of temperature have an apparent response to the SnTe phase transition between cubic and rhombohedral structures at 110 K. The abnormal and rapid increase in subthreshold swing around the phase transition temperature may be due to the soft phonon/structure change which causes the large increase in SnTe dielectric constant. Such an interesting and remarkable electrical response to phase transition at different temperatures makes the small SnTe transistor attractive for various electronic devices.

  12. Phase response curve to 1 h light pulses for the European rabbit (Oryctolagus cuniculus).

    PubMed

    Kennedy, Gerard A; Hudson, Robyn

    2016-01-01

    While much is known about the circadian systems of rodents, chronobiological studies of other mammalian groups have been limited. One of the most extensively studied nonrodent species, both in the laboratory and in the wild, is the European rabbit. The aim of this study was to extend knowledge of the rabbit circadian system by examining its phasic response to light. Twelve Dutch-Himalayan cross rabbits of both sexes were allowed to free-run in constant darkness and then administered 1 h light pulses (1000 lux) at multiple predetermined circadian times. Changes in the phase of the rabbits' circadian wheel-running rhythms were measured after each light pulse and used to construct a phase-response curve (PRC). The rabbits' PRC and free-running period (τ) conformed to the empirical regularities reported for other predominantly nocturnal animals, including rodents and predatory marsupials. The results of the study are thus consistent with reports that the rabbit is essentially a nocturnal animal and show that it can entrain to light/dark (LD) cycles via discrete phase shifts. Knowledge about the rabbit's circadian range of entrainment to LD cycles gained in this study will be useful for examining the putative circadian processes believed to underlie the unusual rhythm of very brief, once-daily nest visits by nursing rabbit mothers and other nursing lagomorphs. PMID:27305519

  13. Changes of firing rate induced by changes of phase response curve in bifurcation transitions.

    PubMed

    Sato, Yasuomi D; Aihara, Kazuyuki

    2014-11-01

    We study dynamical mechanisms responsible for changes of the firing rate during four different bifurcation transitions in the two-dimensional Hindmarsh-Rose (2DHR) neuron model: the saddle node on an invariant circle (SNIC) bifurcation to the supercritical Andronov-Hopf (AH) one, the SNIC bifurcation to the saddle-separatrix loop (SSL) one, the AH bifurcation to the subcritical AH (SAH) one, and the SSL bifurcation to the AH one. For this purpose, we study slopes of the firing rate curve with respect to not only an external input current but also temperature that can be interpreted as a timescale in the 2DHR neuron model. These slopes are mathematically formulated with phase response curves (PRCs), expanding the firing rate with perturbations of the temperature and external input current on the one-dimensional space of the phase [Formula: see text] in the 2DHR oscillator. By analyzing the two different slopes of the firing rate curve with respect to the temperature and external input current, we find that during changes of the firing rate in all of the bifurcation transitions, the calculated slope with respect to the temperature also changes. This is largely dependent on changes in the PRC size that is also related to the slope with respect to the external input current. Furthermore, we find phase transition-like switches of the firing rate with a possible increase of the temperature during the SSL-to-AH bifurcation transition.

  14. Particle-induced pulmonary acute phase response may be the causal link between particle inhalation and cardiovascular disease

    PubMed Central

    Saber, Anne T; Jacobsen, Nicklas R; Jackson, Petra; Poulsen, Sarah Søs; Kyjovska, Zdenka O; Halappanavar, Sabina; Yauk, Carole L; Wallin, Håkan; Vogel, Ulla

    2014-01-01

    Inhalation of ambient and workplace particulate air pollution is associated with increased risk of cardiovascular disease. One proposed mechanism for this association is that pulmonary inflammation induces a hepatic acute phase response, which increases risk of cardiovascular disease. Induction of the acute phase response is intimately linked to risk of cardiovascular disease as shown in both epidemiological and animal studies. Indeed, blood levels of acute phase proteins, such as C-reactive protein and serum amyloid A, are independent predictors of risk of cardiovascular disease in prospective epidemiological studies. In this review, we present and review emerging evidence that inhalation of particles (e.g., air diesel exhaust particles and nanoparticles) induces a pulmonary acute phase response, and propose that this induction constitutes the causal link between particle inhalation and risk of cardiovascular disease. Increased levels of acute phase mRNA and proteins in lung tissues, bronchoalveolar lavage fluid and plasma clearly indicate pulmonary acute phase response following pulmonary deposition of different kinds of particles including diesel exhaust particles, nanoparticles, and carbon nanotubes. The pulmonary acute phase response is dose-dependent and long lasting. Conversely, the hepatic acute phase response is reduced relative to lung or entirely absent. We also provide evidence that pulmonary inflammation, as measured by neutrophil influx, is a predictor of the acute phase response and that the total surface area of deposited particles correlates with the pulmonary acute phase response. We discuss the implications of these findings in relation to occupational exposure to nanoparticles. How to cite this article: WIREs Nanomed Nanobiotechnol 2014, 6:517–531. doi: 10.1002/wnan.1279 PMID:24920450

  15. The Association between Platelet Count and Acute Phase Response in Chronic Spontaneous Urticaria

    PubMed Central

    Kasperska-Zając, Alicja; Grzanka, Alicja; Jarzab, Jerzy; Misiołek, Maciej; Wyszyńska-Chłap, Magdalena; Kasperski, Jacek; Machura, Edyta

    2014-01-01

    Background. The platelet parameters and C-reactive protein (CRP) are markers reflecting a systemic inflammatory response. Among those, CRP is one of the major proteins helpful in determination of severity/activity of chronic spontaneous urticaria (CSU). Aim. To determine relationships between platelet activation indices and serum concentration of CRP, the best marker of acute phase response, and their potential clinical use in CSU patients. Methods. Mean platelet volume (MPV), platelet distribution width (PDW), and platelet count as well as serum CRP concentration were measured in CSU patients, showing different degrees of urticarial severity, and in the healthy subjects. Results. No significant differences were found in MPV and PDW between CSU group and the healthy subjects. The platelet count was significantly higher in moderate-severe CSU than that of the controls and mild CSU patients. Serum CRP concentrations were significantly higher in CSU patients as compared with the healthy subjects and significantly correlated with the platelet count in CSU patients. Conclusions. Acute phase response in CSU is associated with the increased number of circulating platelets in patients with more severe symptoms. It seems that simple determination of platelet size indices is not a reliable indicator of CSU severity/activity. PMID:25025065

  16. Extrinsic and intrinsic regulation of axon regeneration at a crossroads

    PubMed Central

    Kaplan, Andrew; Ong Tone, Stephan; Fournier, Alyson E.

    2015-01-01

    Repair of the injured spinal cord is a major challenge in medicine. The limited intrinsic regenerative response mounted by adult central nervous system (CNS) neurons is further hampered by astrogliosis, myelin debris and scar tissue that characterize the damaged CNS. Improved axon regeneration and recovery can be elicited by targeting extrinsic factors as well as by boosting neuron-intrinsic growth regulators. Our knowledge of the molecular basis of intrinsic and extrinsic regulators of regeneration has expanded rapidly, resulting in promising new targets to promote repair. Intriguingly certain neuron-intrinsic growth regulators are emerging as promising targets to both stimulate growth and relieve extrinsic inhibition of regeneration. This crossroads between the intrinsic and extrinsic aspects of spinal cord injury is a promising target for effective therapies for this unmet need. PMID:26136657

  17. Cold Responsive Gene Expression Profiling of Sugarcane and Saccharum spontaneum with Functional Analysis of a Cold Inducible Saccharum Homolog of NOD26-Like Intrinsic Protein to Salt and Water Stress.

    PubMed

    Park, Jong-Won; Benatti, Thiago R; Marconi, Thiago; Yu, Qingyi; Solis-Gracia, Nora; Mora, Victoria; da Silva, Jorge A

    2015-01-01

    Transcriptome analysis of sugarcane hybrid CP72-1210 (cold susceptible) and Saccharum spontaneum TUS05-05 (cold tolerant) using Sugarcane Assembled Sequences (SAS) from SUCEST-FUN Database showed that a total of 35,340 and 34,698 SAS genes, respectively, were expressed before and after chilling stress. The analysis revealed that more than 600 genes are differentially expressed in each genotype after chilling stress. Blast2Go annotation revealed that the major difference in gene expression profiles between CP72-1210 and TUS05-05 after chilling stress are present in the genes related to the transmembrane transporter activity. To further investigate the relevance of transmembrane transporter activity against abiotic stress tolerance, a S. spontaneum homolog of a NOD26-like major intrinsic protein gene (SspNIP2) was selected for functional analysis, of which expression was induced after chilling stress in the cold tolerant TUS05-05. Quantitative real-time PCR showed that SspNIP2 expression was increased ~2.5 fold at 30 minutes after cold treatment and stayed induced throughout the 24 hours of cold treatment. The amino acid sequence analysis of the cloned SspNIP2 confirmed the presence of six transmembrane domains and two NPA (Asn-Pro-Ala) motifs, signature features of major intrinsic protein families. Amino acid analysis confirmed that four amino acids, comprising the ar/R (aromatic residue/arginine) region responsible for the substrate specificity among MIPs, are conserved among monocot silicon transporters and SspNIP2. Salinity stress test on SspNIP2 transgenic tobacco plants resulted in more vigorous transgenic lines than the non-transgenic tobacco plants, suggesting some degree of tolerance to salt stress conferred by SspNIP2. SspNIP2-transgenic plants, exposed to 2 weeks of water stress without irrigation, developed various degrees of water stress symptom. The water stress test confirmed that the SspNIP2 transgenic lines had lower evapotranspiration rates than non

  18. Habituation of single CO2 laser-evoked responses during interictal phase of migraine.

    PubMed

    de Tommaso, Marina; Libro, Giuseppe; Guido, Marco; Losito, Luciana; Lamberti, Paolo; Livrea, Paolo

    2005-09-01

    A reduced habituation of averaged laser-evoked potential (LEP) amplitudes was previously found in migraine patients. The aim of the present study was to assess the habituation of single LEP responses and pain sensation during the interictal phase in migraine patients. Fourteen migraine patients were compared with ten control subjects. The pain stimulus was laser pulses, generated by CO2 laser, delivered to right supraorbital zone. Patients were evaluated during attack-free conditions. The LEP habituation was studied by measuring the changes of LEP amplitudes across and within three consecutive repetitions of 21 non-averaged trials. In migraine patients the N2-P2 wave amplitudes did not show a tendency toward habituation across and, above all, within the three repetitions. Anomalous behaviour of nociceptive cortex during the interictal phase of migraine may predispose patients to headache occurrence and persistence. PMID:16362662

  19. Habituation of single CO2 laser-evoked responses during interictal phase of migraine.

    PubMed

    de Tommaso, Marina; Libro, Giuseppe; Guido, Marco; Losito, Luciana; Lamberti, Paolo; Livrea, Paolo

    2005-09-01

    A reduced habituation of averaged laser-evoked potential (LEP) amplitudes was previously found in migraine patients. The aim of the present study was to assess the habituation of single LEP responses and pain sensation during the interictal phase in migraine patients. Fourteen migraine patients were compared with ten control subjects. The pain stimulus was laser pulses, generated by CO2 laser, delivered to right supraorbital zone. Patients were evaluated during attack-free conditions. The LEP habituation was studied by measuring the changes of LEP amplitudes across and within three consecutive repetitions of 21 non-averaged trials. In migraine patients the N2-P2 wave amplitudes did not show a tendency toward habituation across and, above all, within the three repetitions. Anomalous behaviour of nociceptive cortex during the interictal phase of migraine may predispose patients to headache occurrence and persistence.

  20. Intrinsic Negative Mass from Nonlinearity

    NASA Astrophysics Data System (ADS)

    Di Mei, F.; Caramazza, P.; Pierangeli, D.; Di Domenico, G.; Ilan, H.; Agranat, A. J.; Di Porto, P.; DelRe, E.

    2016-04-01

    We propose and provide experimental evidence of a mechanism able to support negative intrinsic effective mass. The idea is to use a shape-sensitive nonlinearity to change the sign of the mass in the leading linear propagation equation. Intrinsic negative-mass dynamics is reported for light beams in a ferroelectric crystal substrate, where the diffusive photorefractive nonlinearity leads to a negative-mass Schrödinger equation. The signature of inverted dynamics is the observation of beams repelled from strongly guiding integrated waveguides irrespective of wavelength and intensity and suggests shape-sensitive nonlinearity as a basic mechanism leading to intrinsic negative mass.

  1. Mitochondrial and Chloroplast Stress Responses Are Modulated in Distinct Touch and Chemical Inhibition Phases1[OPEN

    PubMed Central

    Ivanova, Aneta; Millar, A. Harvey; Whelan, James

    2016-01-01

    Previous studies have identified a range of transcription factors that modulate retrograde regulation of mitochondrial and chloroplast functions in Arabidopsis (Arabidopsis thaliana). However, the relative importance of these regulators and whether they act downstream of separate or overlapping signaling cascades is still unclear. Here, we demonstrate that multiple stress-related signaling pathways, with distinct kinetic signatures, converge on overlapping gene sets involved in energy organelle function. The transcription factor ANAC017 is almost solely responsible for transcript induction of marker genes around 3 to 6 h after chemical inhibition of organelle function and is a key regulator of mitochondrial and specific types of chloroplast retrograde signaling. However, an independent and highly transient gene expression phase, initiated within 10 to 30 min after treatment, also targets energy organelle functions, and is related to touch and wounding responses. Metabolite analysis demonstrates that this early response is concurrent with rapid changes in tricarboxylic acid cycle intermediates and large changes in transcript abundance of genes encoding mitochondrial dicarboxylate carrier proteins. It was further demonstrated that transcription factors AtWRKY15 and AtWRKY40 have repressive regulatory roles in this touch-responsive gene expression. Together, our results show that several regulatory systems can independently affect energy organelle function in response to stress, providing different means to exert operational control. PMID:27208304

  2. Molecular predictors of response to decitabine in advanced chronic myelomonocytic leukemia: a phase 2 trial.

    PubMed

    Braun, Thorsten; Itzykson, Raphael; Renneville, Aline; de Renzis, Benoit; Dreyfus, François; Laribi, Kamel; Bouabdallah, Krimo; Vey, Norbert; Toma, Andrea; Recher, Christian; Royer, Bruno; Joly, Bertrand; Vekhoff, Anne; Lafon, Ingrid; Sanhes, Laurence; Meurice, Guillaume; Oréar, Cédric; Preudhomme, Claude; Gardin, Claude; Ades, Lionel; Fontenay, Michaela; Fenaux, Pierre; Droin, Nathalie; Solary, Eric

    2011-10-01

    Hydroxyurea is the standard therapy of chronic myelomonocytic leukemia (CMML) presenting with advanced myeloproliferative and/or myelodysplastic features. Response to hypomethylating agents has been reported in heterogeneous series of CMML. We conducted a phase 2 trial of decitabine (DAC) in 39 patients with advanced CMML defined according to a previous trial. Median number of DAC cycles was 10 (range, 1-24). Overall response rate was 38% with 4 complete responses (10%), 8 marrow responses (21%), and 3 stable diseases with hematologic improvement (8%). Eighteen patients (46%) demonstrated stable disease without hematologic improvement, and 6 (15%) progressed to acute leukemia. With a median follow-up of 23 months, overall survival was 48% at 2 years. Mutations in ASXL1, TET2, AML1, NRAS, KRAS, CBL, FLT3, and janus kinase 2 (JAK2) genes, and hypermethylation of the promoter of the tumor suppressor gene TIF1γ, did not predict response or survival on DAC therapy. Lower CJUN and CMYB gene expression levels independently predicted improved overall survival. This trial confirmed DAC efficacy in approximately 40% of CMML patients with advanced myeloproliferative or myelodysplastic features and suggested that CJUN and CMYB expression could be potential biomarkers in this setting. This trial is registered at EudraCT (eudract.ema.europa.eu) as #2008-000470-21 and www.clinicaltrials.gov as #NCT01098084.

  3. Intrinsic Radiosensitivity and Cellular Characterization of 27 Canine Cancer Cell Lines

    PubMed Central

    Maeda, Junko; Froning, Coral E.; Brents, Colleen A.; Rose, Barbara J.; Thamm, Douglas H.; Kato, Takamitsu A.

    2016-01-01

    Canine cancer cell lines have progressively been developed, but are still underused resources for radiation biology research. Measurement of the cellular intrinsic radiosensitivity is important because understanding the difference may provide a framework for further elucidating profiles for prediction of radiation therapy response. Our studies have focused on characterizing diverse canine cancer cell lines in vitro and understanding parameters that might contribute to intrinsic radiosensitivity. First, intrinsic radiosensitivity of 27 canine cancer cell lines derived from ten tumor types was determined using a clonogenic assay. The 27 cell lines had varying radiosensitivities regardless tumor type (survival fraction at 2 Gy, SF2 = 0.19–0.93). In order to understand parameters that might contribute to intrinsic radiosensitivity, we evaluated the relationships of cellular radiosensitivity with basic cellular characteristics of the cell lines. There was no significant correlation of SF2 with S-phase fraction, doubling time, chromosome number, ploidy, or number of metacentric chromosomes, while there was a statistically significant correlation between SF2 and plating efficiency. Next, we selected the five most radiosensitive cell lines as the radiosensitive group and the five most radioresistant cell lines as the radioresistant group. Then, we evaluated known parameters for cell killing by ionizing radiation, including radiation-induced DNA double strand break (DSB) repair and apoptosis, in the radiosensitive group as compared to the radioresistant group. High levels of residual γ-H2AX foci at the sites of DSBs were present in the four out of the five radiosensitive canine cancer cell lines. Our studies suggested that substantial differences in intrinsic radiosensitivity exist in canine cancer cell lines, and radiation-induced DSB repair was related to radiosensitivity, which is consistent with previous human studies. These data may assist further investigations

  4. Intrinsic Radiosensitivity and Cellular Characterization of 27 Canine Cancer Cell Lines.

    PubMed

    Maeda, Junko; Froning, Coral E; Brents, Colleen A; Rose, Barbara J; Thamm, Douglas H; Kato, Takamitsu A

    2016-01-01

    Canine cancer cell lines have progressively been developed, but are still underused resources for radiation biology research. Measurement of the cellular intrinsic radiosensitivity is important because understanding the difference may provide a framework for further elucidating profiles for prediction of radiation therapy response. Our studies have focused on characterizing diverse canine cancer cell lines in vitro and understanding parameters that might contribute to intrinsic radiosensitivity. First, intrinsic radiosensitivity of 27 canine cancer cell lines derived from ten tumor types was determined using a clonogenic assay. The 27 cell lines had varying radiosensitivities regardless tumor type (survival fraction at 2 Gy, SF2 = 0.19-0.93). In order to understand parameters that might contribute to intrinsic radiosensitivity, we evaluated the relationships of cellular radiosensitivity with basic cellular characteristics of the cell lines. There was no significant correlation of SF2 with S-phase fraction, doubling time, chromosome number, ploidy, or number of metacentric chromosomes, while there was a statistically significant correlation between SF2 and plating efficiency. Next, we selected the five most radiosensitive cell lines as the radiosensitive group and the five most radioresistant cell lines as the radioresistant group. Then, we evaluated known parameters for cell killing by ionizing radiation, including radiation-induced DNA double strand break (DSB) repair and apoptosis, in the radiosensitive group as compared to the radioresistant group. High levels of residual γ-H2AX foci at the sites of DSBs were present in the four out of the five radiosensitive canine cancer cell lines. Our studies suggested that substantial differences in intrinsic radiosensitivity exist in canine cancer cell lines, and radiation-induced DSB repair was related to radiosensitivity, which is consistent with previous human studies. These data may assist further investigations

  5. MUTATIONAL AND TRANSCRIPTIONAL RESPONSES OF STATIONARY- AND LOGARITHMIC-PHASE SALMONELLA TO MX: CORRELATION OF MUTATIONAL RESPONSE TO CHANGES IN GENE EXPRESSION

    EPA Science Inventory

    We measured the mutational and transcriptional response of stationary-phase and logarithmic-phase S. typhimurium TA100 to 3 concentrations of the drinking water mutagen 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX). The mutagenicity of MX in strain TA100 was evaluated...

  6. Cellular immune response of patients with neurocysticercosis (inflammatory and non-inflammatory phases).

    PubMed

    Bueno, Ednéia Casagranda; dos Ramos Machado, Luís; Livramento, José Antônio; Vaz, Adelaide José

    2004-07-01

    The cellular immune response in neurocysticercosis (NC) was studied in 22 patients, 11 (50%) of them in the inflammatory phase of the disease, by means of immunophenotyping of cells in cerebrospinal fluid (CSF) and peripheral blood (PB), lymphoproliferation assay with Taenia solium total saline extract (Tso) and Taenia crassiceps vesicular fluid (Tcra) as stimuli, and by determining the cytokine production profile in the cell culture supernatant. A higher mean percentage of CD19+ and CD56+ cells was observed in the CSF samples from inflammatory (16.8 and 11.3%) and non-inflammatory NC-patients (14.1 and 8.4%) when compared with the control group (CG, 7.6 and 5.4%). The CSF samples from inflammatory NC-patients also showed a higher percentage of HCAM (19.1%) and ICAM (44.9%) adhesion molecules when compared to CG (3.1 and 4.8%). The inflammatory phase showed predominance of CD8+ cells (CSF 26.6% and PB 36.2%) when compared with non-inflammatory phase (CSF 21.5% and PB 29.0%). All cell populations identified in the CSF from NC-patients showed cell activation (CD69+). The cell populations identified in PB showed higher expression of CD69 during the inflammatory phase, while only CD4+ cells presented no cell activation during the non-inflammatory phase. The antigen-specific lymphoproliferation assay showed mean positive results (stimulation index, SI > or = 2.5) only for cells from inflammatory NC-patients (Tcra 3.2 and Tso 5.4), but less intense than the CG (Tcra 5.7 and Tso 8.9). The cytokine production profile when using Tso antigen as stimuli showed differences between NC-patients with inflammatory (production of IL-4/IL-12/TNF-alpha/ICAM/VCAM) and non-inflammatory phase (production of IL-6/IL-10/IL-12/TNF-alpha/ICAM/VCAM). A prevalence of Th2 profile was observed in nine (69%) of the 13 (62% of total) NC-patients presenting positive SI. Cells from inflammatory NC-patients showed a predominance of a Th1 response upon in vitro stimulation, while those from non

  7. Effect of Phase on Human Responses to Vertical Whole-Body Vibration and SHOCK—ANALYTICAL Investigation

    NASA Astrophysics Data System (ADS)

    MATSUMOTO, Y.; GRIFFIN, M. J.

    2002-03-01

    The effect of the “phase” on human responses to vertical whole-body vibration and shock has been investigated analytically using alternative methods of predicting subjective responses (using r.m.s., VDV and various frequency weightings). Two types of phase have been investigated: the effect of the relative phase between two frequency components in the input stimulus, and the phase response of the human body. Continuous vibrations and shocks, based on half-sine and one-and-a-half-sine accelerations, each of which had two frequency components, were used as input stimuli. For the continuous vibrations, an effect of relative phase was found for the vibration dose value (VDV) when the ratio between two frequency components was three: about 12% variation in the VDV of the unweighted acceleration was possible by changing the relative phase. The effect of the phase response of the body represented by frequency weightings was most significant when the frequencies of two sinusoidal components were about 3 and 9 Hz. With shocks, the effect of relative phase was observed for all stimuli used. The variation in the r.m.s. acceleration and in the VDV caused by variations in the relative phase varied between 3 and 100%, depending on the nature of stimulus and the frequency weighting. The phase of the frequency weightings had a different effect on the r.m.s. and the VDV.

  8. Ultrafast optical response of the amorphous and crystalline states of the phase change material Ge2Sb2Te5

    NASA Astrophysics Data System (ADS)

    Miller, T. A.; Rudé, M.; Pruneri, V.; Wall, S.

    2016-07-01

    We examine the ultrafast optical response of the crystalline and amorphous phases of the phase change material Ge2Sb2Te5 (GST) below the phase transformation threshold. Simultaneous measurement of the transmissivity and reflectivity of thin film samples yields the time-dependent evolution of the dielectric function for both phases. We then identify how lattice motion and electronic excitation manifest in the dielectric response. The dielectric response of both phases is large but markedly different. At 800 nm, the changes in amorphous GST are well described by the Drude response of the generated photocarriers, whereas the crystalline phase is better described by the depopulation of resonant bonds. We find that the generated coherent phonons have a greater influence in the amorphous phase than the crystalline phase. Furthermore, coherent phonons do not influence resonant bonding. For fluences up to 50% of the transformation threshold, the structure does not exhibit bond softening in either phase, enabling large changes of the optical properties without structural modification.

  9. Repeated allergen exposure reduce early phase airway response and leukotriene release despite upregulation of 5-lipoxygenase pathways

    PubMed Central

    2012-01-01

    Background Allergen induced early phase airway response and airway plasma exudation are predominantly mediated by inflammatory mast cell mediators including histamine, cysteinyl leukotrienes (cysLTs) and thromboxane A2 (TXA2). The aim of the present study was to evaluate whether repeated allergen exposure affects early phase airway response to allergen challenge. Methods A trimellitic anhydride (TMA) sensitized guinea pig model was used to investigate the effects of low dose repeated allergen exposure on cholinergic airway responsiveness, early phase airway response and plasma exudation, as well as local airway production of mast cell derived cysteinyl leukotrienes and thromboxane B2 (TXB2) after allergen challenge. Results Repeated low dose allergen exposure increased cholinergic airway responsiveness. In contrast, early phase airway response and plasma exudation in response to a high-dose allergen challenge were strongly attenuated after repeated low dose allergen exposure. Inhibition of the airway response was unspecific to exposed allergen and independent of histamine receptor blocking. Furthermore, a significant reduction of cysteinyl leukotrienes and TXB2 was found in the airways of animals repeatedly exposed to a low dose allergen. However, in vitro stimulation of airway tissue from animals repeatedly exposed to a low dose allergen with arachidonic acid and calcium ionophore (A23187) induced production of cysteinyl leukotrienes and TXB2, suggesting enhanced activity of 5-lipoxygenase and cyclooxygenase pathways. Conclusions The inhibition of the early phase airway response, cysteinyl leukotriene and TXB2 production after repeated allergen exposure may result from unresponsive effector cells. PMID:22439792

  10. Instantaneous kinematic phase reflects neuromechanical response to lateral perturbations of running cockroaches.

    PubMed

    Revzen, Shai; Burden, Samuel A; Moore, Talia Y; Mongeau, Jean-Michel; Full, Robert J

    2013-04-01

    Instantaneous kinematic phase calculation allows the development of reduced-order oscillator models useful in generating hypotheses of neuromechanical control. When perturbed, changes in instantaneous kinematic phase and frequency of rhythmic movements can provide details of movement and evidence for neural feedback to a system-level neural oscillator with a time resolution not possible with traditional approaches. We elicited an escape response in cockroaches (Blaberus discoidalis) that ran onto a movable cart accelerated laterally with respect to the animals' motion causing a perturbation. The specific impulse imposed on animals (0.50 [Formula: see text] 0.04 m s[Formula: see text]; mean, SD) was nearly twice their forward speed (0.25 [Formula: see text] 0.06 m s[Formula: see text]. Instantaneous residual phase computed from kinematic phase remained constant for 110 ms after the onset of perturbation, but then decreased representing a decrease in stride frequency. Results from direct muscle action potential recordings supported kinematic phase results in showing that recovery begins with self-stabilizing mechanical feedback followed by neural feedback to an abstracted neural oscillator or central pattern generator. Trials fell into two classes of forward velocity changes, while exhibiting statistically indistinguishable frequency changes. Animals pulled away from the side with front and hind legs of the tripod in stance recovered heading within 300 ms, whereas animals that only had a middle leg of the tripod resisting the pull did not recover within this period. Animals with eight or more legs might be more robust to lateral perturbations than hexapods.

  11. Learning intrinsic excitability in medium spiny neurons

    PubMed Central

    Scheler, Gabriele

    2014-01-01

    We present an unsupervised, local activation-dependent learning rule for intrinsic plasticity (IP) which affects the composition of ion channel conductances for single neurons in a use-dependent way. We use a single-compartment conductance-based model for medium spiny striatal neurons in order to show the effects of parameterization of individual ion channels on the neuronal membrane potential-curent relationship (activation function). We show that parameter changes within the physiological ranges are sufficient to create an ensemble of neurons with significantly different activation functions. We emphasize that the effects of intrinsic neuronal modulation on spiking behavior require a distributed mode of synaptic input and can be eliminated by strongly correlated input. We show how modulation and adaptivity in ion channel conductances can be utilized to store patterns without an additional contribution by synaptic plasticity (SP). The adaptation of the spike response may result in either "positive" or "negative" pattern learning. However, read-out of stored information depends on a distributed pattern of synaptic activity to let intrinsic modulation determine spike response. We briefly discuss the implications of this conditional memory on learning and addiction. PMID:25520776

  12. A quantitative model of the phase behavior of recombinant pH-responsive elastin-like polypeptides

    PubMed Central

    MacKay, J. Andrew; Callahan, Daniel J.; FitzGerald, Kelly N.; Chilkoti, Ashutosh

    2010-01-01

    Quantitative models are required to engineer biomaterials with environmentally responsive properties. With this goal in mind, we developed a model that describes the pH dependent phase behavior of a class of stimulus responsive elastin-like polypeptides (ELPs) that undergo reversible phase separation in response to their solution environment. Under isothermal conditions, charged ELPs can undergo phase separation when their charge is neutralized. Optimization of this behavior has been challenging because the pH at which they phase separate, pHt, depends on their composition, molecular weight, concentration, and temperature. To address this problem, we developed a quantitative model to describe the phase behavior of charged ELPs that uses the Henderson-Hasselbalch relationship to describe the effect of side-chain ionization on the phase transition temperature of an ELP. The model was validated with pH-responsive ELPs that contained either acidic (Glu) or basic (His) residues. The phase separation of both ELPs fit this model across a range of pH. These results have important implications for applications of pH-responsive elastin-like polypeptides, because they provide a quantitative model for the rational design of pH responsive polypeptides whose transition can be triggered at a specified pH. PMID:20925333

  13. Polarization-independent and submillisecond response phase modulators using a 90° twisted dual-frequency liquid crystal

    NASA Astrophysics Data System (ADS)

    Huang, Yuhua; Wen, Chien-Hui; Wu, Shin-Tson

    2006-07-01

    A polarization-independent phase modulator using a 90° twisted dual-frequency liquid crystal (DFLC) is demonstrated. In addition to being polarization independent, such a phase modulator exhibits many other advantages such as being scattering-free and having large phase change, low operating voltage, and submillisecond response time. Using a 15μm transmissive DFLC cell, the phase shift achieves 1π at λ =633nm and the applied voltage is lower than 25Vrms. Potential applications of such a phase modulator for laser beam steering, tunable-focus lenses, and switchable two-dimensional/three-dimensional liquid crystal displays are foreseeable.

  14. Cachexia - an intrinsic factor in wound healing.

    PubMed

    Ng, Michael F Y

    2010-04-01

    Systemic diseases are intrinsic factors that alter and may impair the wound healing process. Cachexia is a manifestation of systemic, often chronic, diseases and is characterised by systemic inflammation, appetite suppression and skeletal muscle wasting. Anorexia in cachectic states is commonly associated with malnutrition. Malnutrition may cause impaired healing. Therefore, it would follow that cachexia could influence wound healing because of reduced food intake. However, the lack of response to measures to reverse cachexia, such as supported nutrition, would suggest that a direct causal link between anorexia and weight loss in cachexia is too simple a model. To date, there is no published literature that examines the role of cachexia in human wound healing specifically. This article aims to demonstrate that cachexia is an intrinsic factor in wound healing. The role of the common mediators in wound healing and in cachexia are compared - specifically inflammation, including the nitric oxide synthase pathway, collagen deposition and reepithelialisation.

  15. Two-phase dynamics of p53 in the DNA damage response

    PubMed Central

    Zhang, Xiao-Peng; Liu, Feng; Wang, Wei

    2011-01-01

    The tumor suppressor p53 mainly induces cell cycle arrest/DNA repair or apoptosis in the DNA damage response. How to choose between these two outcomes is not fully understood. We proposed a four-module model of the p53 signaling network and associated the network dynamics with cellular outcomes after ionizing radiation. We found that the cellular response is mediated by both the level and posttranslational modifications of p53 and that p53 is activated in a progressive manner. First, p53 is partially activated by primary modifications such as phosphorylation at Ser-15/20 to induce cell cycle arrest, with its level varying in a series of pulses. If the damage cannot be fixed after a critical number of p53 pulses, then p53 is fully activated by further modifications such as phosphorylation at Ser-46 to trigger apoptosis, with its concentration switching to rather high levels. Thus, p53 undergoes a two-phase response in irreparably damaged cells. Such combinations of pulsatile and switch-like behaviors of p53 may represent a flexible and efficient control mode, avoiding the premature apoptosis and promoting the execution of apoptosis. In our model, p53 pulses are recurrently driven by ataxia telangiectasia mutated (ATM) pulses triggered by DNA damage. The p53-Mdm2 and ATM-p53-Wip1 negative feedback loops are responsible for p53 pulses, whereas the switching behavior occurs when the p53-PTEN-Akt-Mdm2 positive feedback loop becomes dominant. Our results suggest that a sequential predominance of distinct feedback loops may elicit multiple-phase dynamical behaviors. This work provides a new mechanism for p53 dynamics and cell fate decision. PMID:21576488

  16. Super-resolution ultrasound imaging using a phase-coherent MUSIC method with compensation for the phase response of transducer elements.

    PubMed

    Labyed, Yassin; Huang, Lianjie

    2013-06-01

    Time-reversal with multiple signal classification (TR-MUSIC) is an imaging method for locating point-like targets beyond the classic resolution limit. In the presence of noise, however, the super-resolution capability of TR-MUSIC is diminished. Recently a new method, phase-coherent MUSIC (PC-MUSIC), was developed. This algorithm modifies TR-MUSIC to make use of phase information from multiple frequencies to reduce noise effects and preserve the super resolution. PC-MUSIC however, ignores the phase response of the transducer elements. In this paper, we account for the phase response of the transducer elements in the derivation of the PC-MUSIC algorithm. Unfortunately, the phase response of the transducer elements may not be known beforehand. We develop an experimental method to estimate this response using measured signals scattered from a glass microsphere embedded in a tissue-mimicking phantom with a homogeneous background medium of a known sound speed. We use numerical simulations to illustrate that the maximum resolution achieved with PC-MUSIC is limited by the transducer bandwidth and the signal-to-noise ratio. We perform experiments on tissue-mimicking phantoms and compare images obtained with different imaging modalities, including X-ray mammography, synthetic-aperture ultrasound imaging, TR-MUSIC, and PC-MUSIC. We demonstrate the significantly improved resolving power of PC-MUSIC. PMID:25004469

  17. NRF2 and the Phase II Response in Acute Stress Resistance Induced by Dietary Restriction

    PubMed Central

    Hine, Christopher M.; Mitchell, James R.

    2013-01-01

    Dietary restriction (DR) as a means to increase longevity is well-established in a number of model organisms from yeast to primates. DR also improves metabolic fitness and increases resistance to acute oxidative, carcinogenic and toxicological stressors - benefits with more immediate potential for clinical translation than increased lifespan. While the detailed mechanism of DR action remains unclear, a conceptual framework involving an adaptive, or hormetic response to the stress of nutrient/energy deprivation has been proposed. A key prediction of the hormesis hypothesis of DR is that beneficial adaptations occur in response to an increase in reactive oxygen/nitrogen species (ROS). These ROS may be derived either from increased mitochondrial respiration or increased xenobiotic metabolism in the case of some DR mimetics. This review will focus on the potential role of the redox-sensing transcription factor NF-E2-related factor 2 (NRF2) and its control of the evolutionarily conserved antioxidant/redox cycling and detoxification systems, collectively known as the Phase II response, in the adaptive response to DR. PMID:23505614

  18. Phases

    NASA Technical Reports Server (NTRS)

    1999-01-01

    The Access to Space Agent is responsible for the successful provision of timely, comprehensive information regarding access opportunities, technical details specific to each opportunity, related cost information, and supplier specified points-of-contact.

  19. Pressure responses of portlandite and H-D isotope effects on pressure-induced phase transitions

    NASA Astrophysics Data System (ADS)

    Iizuka, Riko; Kagi, Hiroyuki; Komatsu, Kazuki; Ushijima, Daichi; Nakano, Satoshi; Sano-Furukawa, Asami; Nagai, Takaya; Yagi, Takehiko

    2011-12-01

    The pressure responses of portlandite and the isotope effect on the phase transition were investigated at room temperature from single-crystal Raman and IR spectra and from powder X-ray diffraction using diamond anvil cells under quasi-hydrostatic conditions in a helium pressure-transmitting medium. Phase transformation and subsequent peak broadening (partial amorphization) observed from the Raman and IR spectra of Ca(OH)2 occurred at lower pressures than those of Ca(OD)2. In contrast, no isotope effect was found on the volume and axial compressions observed from powder X-ray diffraction patterns. X-ray diffraction lines attributable to the high-pressure phase remained up to 28.5 GPa, suggesting no total amorphization in a helium pressure medium within the examined pressure region. These results suggest that the H-D isotope effect is engendered in the local environment surrounding H(D) atoms. Moreover, the ratio of sample-to-methanol-ethanol pressure medium (i.e., packing density) in the sample chamber had a significant effect on the increase in the half widths of the diffraction lines, even at pressures below the hydrostatic limit of the pressure medium.

  20. Multidimensional representations of the phase response curve for both type 1 and type 2 membrane excitability

    NASA Astrophysics Data System (ADS)

    Raidt, Robert; Smith, Andrew J.; Oprisan, Sorinel A.

    2012-02-01

    Neurons are complex excitable cells with a highly nonlinear response to external perturbations, such as presynaptic inputs and biological noise. Single-cell activity is determined by the properties of ionic channels and the ionic makeup of cell's environment and is mathematically described by coupled and nonlinear evolution equations. The phase resetting curve (PRC) reduces the complexity of the biophysical mechanisms involved in generating action potentials to tabulating advances or delays of subsequent spikes of a neuron due to an external perturbation. The PRC is widely used to predict the activity of large neural networks that by replacing the computationally intensive integration of evolution equations with lookup tables. The fundamental assumption of the PRC approach in predicting phase-locked modes in coupled neural networks is that the transient PRC measured for isolated and bursting neurons (open-loop) remains the same under the recurrent inputs of a phase-locked mode (close-loop). The novelties of our approach are: 1) the use of discrete sine transforms (DST's) to store the PRC's as a series of coefficients, and 2) the use of multidimensional stacks to represent multidimensional objects.

  1. Flexible designs for phase II comparative clinical trials involving two response variables.

    PubMed

    Bersimis, S; Sachlas, A; Papaioannou, T

    2015-01-30

    The aim of phase II clinical trials is to determine whether an experimental treatment is sufficiently promising and safe to justify further testing. The need for reduced sample size arises naturally in phase II clinical trials owing to both technical and ethical reasons, motivating a significant part of research in the field during recent years, while another significant part of the research effort is aimed at more complex therapeutic schemes that demand the consideration of multiple endpoints to make decisions. In this paper, our attention is restricted to phase II clinical trials in which two treatments are compared with respect to two dependent dichotomous responses proposing some flexible designs. These designs permit the researcher to terminate the clinical trial when high rates of favorable or unfavorable outcomes are observed early enough requiring in this way a small number of patients. From the mathematical point of view, the proposed designs are defined on bivariate sequences of multi-state trials, and the corresponding stopping rules are based on various distributions related to the waiting time until a certain number of events appear in these sequences. The exact distributions of interest, under a unified framework, are studied using the Markov chain embedding technique, which appears to be very useful in clinical trials for the sample size determination. Tables of expected sample size and power are presented. The numerical illustration showed a very good performance for these new designs.

  2. Responsive Gel-Gel Phase Transitions in Artificially Engineered Protein Hydrogels

    NASA Astrophysics Data System (ADS)

    Olsen, B. D.

    2012-02-01

    Artificially engineered protein hydrogels provide an attractive platform for biomedical materials due to their similarity to components of the native extracellular matrix. Engineering responsive transitions between shear-thinning and tough gel phases in these materials could potentially enable gels that are both shear-thinning and tough to be produced as novel injectable biomaterials. To engineer a gel with such transitions, a triblock copolymer with thermoresponsive polymer endblocks and an artificially engineered protein gel midblock is designed. Temperature is used to trigger a transition from a single network protein hydrogel phase to a double network phase with both protein and block copolymer networks present at different length scales. The thermodynamics of network formation and resulting structural changes are established using small-angle scattering, birefringence, and dynamic scanning calorimetry. The formation of the second network is shown to produce a large, nonlinear increase in the elastic modulus as well as enhancements in creep compliance and toughness. Although the gels show yielding behavior in both the single and double network regimes, a qualitative change in the deformation mechanism is observed due to the structural changes.

  3. Detecting a preformed pair phase: Response to a pairing forcing field

    NASA Astrophysics Data System (ADS)

    Tagliavini, A.; Capone, M.; Toschi, A.

    2016-10-01

    The normal state of strongly coupled superconductors is characterized by the presence of "preformed" Cooper pairs well above the superconducting critical temperature. In this regime, the electrons are paired, but they lack the phase coherence necessary for superconductivity. The existence of preformed pairs implies the existence of a characteristic energy scale associated with a pseudogap. Preformed pairs are often invoked to interpret systems where some signatures of pairing are present without actual superconductivity, but an unambiguous theoretical characterization of a preformed-pair system is still lacking. To fill this gap, we consider the response to an external pairing field of an attractive Hubbard model, which hosts one of the cleanest realizations of a preformed pair phase, and a repulsive model where s -wave superconductivity cannot be realized. Using dynamical mean-field theory to study this response, we identify the characteristic features which distinguish the reaction of a preformed pair state from a normal metal without any precursor of pairing. The theoretical detection of preformed pairs is associated with the behavior of the second derivative of the order parameter with respect to the external field, as confirmed by analytic calculations in limiting cases. Our findings provide a solid test bed for the interpretation of state-of-the-art calculations for the normal state of the doped Hubbard model in terms of d -wave preformed pairs and, in perspective, of nonequilibrium experiments in high-temperature superconductors.

  4. Tail biting induces a strong acute phase response and tail-end inflammation in finishing pigs.

    PubMed

    Heinonen, Mari; Orro, Toomas; Kokkonen, Teija; Munsterhjelm, Camilla; Peltoniemi, Olli; Valros, Anna

    2010-06-01

    The extent of inflammation associated with tail biting in finishing pigs was evaluated. Tail histopathology, carcass condemnation and the concentration of three acute phase proteins (APPs), C-reactive protein (CRP), serum amyloid-A (SAA) and haptoglobin (Hp), were examined in 12 tail-bitten and 13 control pigs. The median concentrations of APPs were higher (P<0.01) in bitten (CRP 617.5mg/L, range 80.5-969.9; SAA 128.0mg/L, 6.2-774.4; Hp 2.8g/L, 1.6-3.5) than in control pigs (CRP 65.7mg/L, 28.4-180.4; SAA 6.2mg/L, 6.2-21.4; Hp 1.2g/L, 0.9-1.5). There was a tendency for APP concentrations to rise with the histopathological score but the differences were only statistically significant between some of the scores. Five (42%) bitten cases and one (8%) control pig had partial carcass condemnations owing to abscesses (P=0.07). The results show that tail biting induces an inflammatory response in the tail end leading to an acute phase response and formation of carcass abscesses. PMID:19398209

  5. Surface chemical-modification for engineering the intrinsic physical properties of inorganic two-dimensional nanomaterials.

    PubMed

    Guo, Yuqiao; Xu, Kun; Wu, Changzheng; Zhao, Jiyin; Xie, Yi

    2015-02-01

    Two-dimensional (2D) nanomaterials, especially the inorganic ultrathin nanosheets with single or few-atomic layers, have been extensively studied due to their special structures and rich physical properties coming from the quantum confinement of electrons. With atomic-scale thickness, 2D nanomaterials have an extremely high specific surface area enabling their surface phase to be as important as bulk counterparts, and therefore provide an alternative way of modifying the surface phase for engineering the intrinsic physical properties of inorganic 2D nanomaterials. In this review, we focus on recent research concerning surface chemical modification strategies to effectively engineer the intrinsic physical properties of inorganic 2D nanomaterials. We highlight the newly developed regulation strategies of surface incorporation, defect engineering, and structure modulation of inorganic 2D nanomaterials, which respectively influence the intrinsic conductivity, band structure, and magnetism while maintaining the primary 2D freestanding structures that are vital for 2D based ultrasensitive electronic response, enhanced catalytic and magnetocaloric capabilities.

  6. Nature of men and higher animals' response to the lunar phases.

    NASA Astrophysics Data System (ADS)

    Troshichev, Oleg; Vladimir, Vorobeichikov; Viktor, Stepanov; Eduard, Gorshkov

    The Moon impact on the abnormal behavior of men and higher animals was marked during the entire mankind history, but the nature of this effect remained unclear. The popular hypothesis of the tidal influence of the Moon on the living organisms turned out to be incompatible with the contemporary biophysics concepts. In addition, the estimates of the lunar gravity influence on the men organism showed the negligible value of the possible effect. Vorobeichikov et al. [2006] were the first who suggested that the organisms' response to the lunar phases can be linked with the bacillus E.coli inhabiting in the bowels of the living organisms. E.coli belongs to family of enterobacteria, which are the important component of the human body microflora. Bacteria E.coli being sowed in the nutritious medium go in their development through four stages: adjusting, explosive reproducing, stationary, and dieing. The adjusting stage (or lagphase) is the most interesting for researchers, since duration of this phase L (the interval between the sowing time and the onset of the quick, exponential reproduction) is strongly influenced by the external conditions and can vary from standard 3 - 3.5 hours to some minutes. In our experiments the lag-phase L was determined for days of new moon and full moon, and for such exclusive events as the solar and lunar eclipses. The standard quantity of E.coli was sowed in the standard volume of the artificial nutritive. Lag-phase was detected every 1 minute near the key moment and every 15 minutes at other hours. It turned out that lag-phase is reduced to 1.5 hour for new moon, 1 hour for full moon, 0.5 hour for the lunar eclipse and falls to zero for the solar eclipse. In the latter case it took about 10 hours for the lag phase reduction before the eclipse and the lag-phase recovery after the eclipse. In case of a new moon the lag phase reduction lasted about half of hour. Thus, the close was the Moon to the line Sun-Earth, the shorter was lag phase and

  7. Demand Response Spinning Reserve Demonstration -- Phase 2 Findings from the Summer of 2008

    SciTech Connect

    Eto, Joseph H.; Nelson-Hoffman, Janine; Parker, Eric; Bernier, Clark; Young, Paul; Sheehan, Dave; Kueck, John; Kirby, Brendan

    2009-04-30

    The Demand Response Spinning Reserve project is a pioneering demonstration showing that existing utility load-management assets can provide an important electricity system reliability resource known as spinning reserve. Using aggregated demand-side resources to provide spinning reserve as demonstrated in this project will give grid operators at the California Independent System Operator (CA ISO) and Southern California Edison (SCE) a powerful new tool to improve reliability, prevent rolling blackouts, and lower grid operating costs.In the first phase of this demonstration project, we target marketed SCE?s air-conditioning (AC) load-cycling program, called the Summer Discount Plan (SDP), to customers on a single SCE distribution feederand developed an external website with real-time telemetry for the aggregated loads on this feeder and conducted a large number of short-duration curtailments of participating customers? air-conditioning units to simulate provision of spinning reserve. In this second phase of the demonstration project, we explored four major elements that would be critical for this demonstration to make the transition to a commercial activity:1. We conducted load curtailments within four geographically distinct feeders to determine the transferability of target marketing approaches and better understand the performance of SCE?s load management dispatch system as well as variations in the AC use of SCE?s participating customers;2. We deployed specialized, near-real-time AC monitoring devices to improve our understanding of the aggregated load curtailments we observe on the feeders;3. We integrated information provided by the AC monitoring devices with information from SCE?s load management dispatch system to measure the time required for each step in the curtailment process; and4. We established connectivity with the CA ISO to explore the steps involved in responding to CA ISO-initiated requests for dispatch of spinning reserve.The major findings from

  8. Acute phase response in two consecutive experimentally induced E. coli intramammary infections in dairy cows

    PubMed Central

    Suojala, Leena; Orro, Toomas; Järvinen, Hanna; Saatsi, Johanna; Pyörälä, Satu

    2008-01-01

    Background Acute phase proteins haptoglobin (Hp), serum amyloid A (SAA) and lipopolysaccharide binding protein (LBP) have suggested to be suitable inflammatory markers for bovine mastitis. The aim of the study was to investigate acute phase markers along with clinical parameters in two consecutive intramammary challenges with Escherichia coli and to evaluate the possible carry-over effect when same animals are used in an experimental model. Methods Mastitis was induced with a dose of 1500 cfu of E. coli in one quarter of six cows and inoculation repeated in another quarter after an interval of 14 days. Concentrations of acute phase proteins haptoglobin (Hp), serum amyloid A (SAA) and lipopolysaccharide binding protein (LBP) were determined in serum and milk. Results In both challenges all cows became infected and developed clinical mastitis within 12 hours of inoculation. Clinical disease and acute phase response was generally milder in the second challenge. Concentrations of SAA in milk started to increase 12 hours after inoculation and peaked at 60 hours after the first challenge and at 44 hours after the second challenge. Concentrations of SAA in serum increased more slowly and peaked at the same times as in milk; concentrations in serum were about one third of those in milk. Hp started to increase in milk similarly and peaked at 36–44 hours. In serum, the concentration of Hp peaked at 60–68 hours and was twice as high as in milk. LBP concentrations in milk and serum started to increase after 12 hours and peaked at 36 hours, being higher in milk. The concentrations of acute phase proteins in serum and milk in the E. coli infection model were much higher than those recorded in experiments using Gram-positive pathogens, indicating the severe inflammation induced by E. coli. Conclusion Acute phase proteins would be useful parameters as mastitis indicators and to assess the severity of mastitis. If repeated experimental intramammary induction of the same animals

  9. Distinct phosphatases antagonize the p53 response in different phases of the cell cycle

    PubMed Central

    Shaltiel, Indra A.; Aprelia, Melinda; Saurin, Adrian T.; Chowdhury, Dipanjan; Kops, Geert J. P. L.; Voest, Emile E.; Medema, René H.

    2014-01-01

    The basic machinery that detects DNA damage is the same throughout the cell cycle. Here, we show, in contrast, that reversal of DNA damage responses (DDRs) and recovery are fundamentally different in G1 and G2 phases of the cell cycle. We find that distinct phosphatases are required to counteract the checkpoint response in G1 vs. G2. Whereas WT p53-induced phosphatase 1 (Wip1) promotes recovery in G2-arrested cells by antagonizing p53, it is dispensable for recovery from a G1 arrest. Instead, we identify phosphoprotein phosphatase 4 catalytic subunit (PP4) to be specifically required for cell cycle restart after DNA damage in G1. PP4 dephosphorylates Krüppel-associated box domain-associated protein 1-S473 to repress p53-dependent transcriptional activation of p21 when the DDR is silenced. Taken together, our results show that PP4 and Wip1 are differentially required to counteract the p53-dependent cell cycle arrest in G1 and G2, by antagonizing early or late p53-mediated responses, respectively. PMID:24711418

  10. A phase transition model for the speed-accuracy trade-off in response time experiments.

    PubMed

    Dutilh, Gilles; Wagenmakers, Eric-Jan; Visser, Ingmar; van der Maas, Han L J

    2011-03-01

    Most models of response time (RT) in elementary cognitive tasks implicitly assume that the speed-accuracy trade-off is continuous: When payoffs or instructions gradually increase the level of speed stress, people are assumed to gradually sacrifice response accuracy in exchange for gradual increases in response speed. This trade-off presumably operates over the entire range from accurate but slow responding to fast but chance-level responding (i.e., guessing). In this article, we challenge the assumption of continuity and propose a phase transition model for RTs and accuracy. Analogous to the fast guess model (Ollman, 1966), our model postulates two modes of processing: a guess mode and a stimulus-controlled mode. From catastrophe theory, we derive two important predictions that allow us to test our model against the fast guess model and against the popular class of sequential sampling models. The first prediction--hysteresis in the transitions between guessing and stimulus-controlled behavior--was confirmed in an experiment that gradually changed the reward for speed versus accuracy. The second prediction--bimodal RT distributions--was confirmed in an experiment that required participants to respond in a way that is intermediate between guessing and accurate responding.

  11. Acute phase response, inflammation and metabolic syndrome biomarkers of Libby asbestos exposure

    SciTech Connect

    Shannahan, Jonathan H.; Alzate, Oscar; Winnik, Witold M.; Andrews, Debora; Schladweiler, Mette C.; Ghio, Andrew J.; Gavett, Stephen H.; Kodavanti, Urmila P.

    2012-04-15

    Identification of biomarkers assists in the diagnosis of disease and the assessment of health risks from environmental exposures. We hypothesized that rats exposed to Libby amphibole (LA) would present with a unique serum proteomic profile which could help elucidate epidemiologically-relevant biomarkers. In four experiments spanning varied protocols and temporality, healthy (Wistar Kyoto, WKY; and F344) and cardiovascular compromised (CVD) rat models (spontaneously hypertensive, SH; and SH heart failure, SHHF) were intratracheally instilled with saline (control) or LA. Serum biomarkers of cancer, inflammation, metabolic syndrome (MetS), and the acute phase response (APR) were analyzed. All rat strains exhibited acute increases in α-2-macroglobulin, and α1-acid glycoprotein. Among markers of inflammation, lipocalin-2 was induced in WKY, SH and SHHF and osteopontin only in WKY after LA exposure. While rat strain- and age-related changes were apparent in MetS biomarkers, no LA effects were evident. The cancer marker mesothelin was increased only slightly at 1 month in WKY in one of the studies. Quantitative Intact Proteomic profiling of WKY serum at 1 day or 4 weeks after 4 weekly LA instillations indicated no oxidative protein modifications, however APR proteins were significantly increased. Those included serine protease inhibitor, apolipoprotein E, α-2-HS-glycoprotein, t-kininogen 1 and 2, ceruloplasmin, vitamin D binding protein, serum amyloid P, and more 1 day after last LA exposure. All changes were reversible after a short recovery regardless of the acute or long-term exposures. Thus, LA exposure induces an APR and systemic inflammatory biomarkers that could have implications in systemic and pulmonary disease in individuals exposed to LA. -- Highlights: ► Biomarkers of asbestos exposure are required for disease diagnosis. ► Libby amphibole exposure is associated with increased human mortality. ► Libby amphibole increases circulating proteins involved

  12. Location, Partitioning Behavior, and Interaction of Capsaicin with Lipid Bilayer Membrane: Study Using Its Intrinsic Fluorescence.

    PubMed

    Swain, Jitendriya; Kumar Mishra, Ashok

    2015-09-10

    Capsaicin is an ingredient of a wide variety of red peppers, and it has various pharmacological and biological applications. The present study explores the interaction of capsaicin with dimyristoylphosphatidylcholine (DMPC) lipid bilayer membrane by monitoring various photophysical parameters using its intrinsic fluorescence. In order to have a clearer understanding of the photophysical responses of capsaicin, studies involving (i) its solvation behavior in different solvents, (ii) the partition coefficient of capsaicin in different thermotropic phase states of lipid bilayer membrane, and (iii) its location inside lipid bilayer membrane have been carried out. Capsaicin has a reasonably high partition coefficient for DMPC liposome membrane, in both solid gel (2.8 ± 0.1 × 10(5)) and liquid crystalline (2.6 ± 0.1 × 10(5)) phases. Fluorescence quenching study using cetylpyridinium chloride (CPC) as quencher suggests that the phenolic group of capsaicin molecule is generally present near the headgroup region and hydrophobic tail present inside hydrophobic core region of the lipid bilayer membrane. The intrinsic fluorescence intensity and lifetime of capsaicin sensitively respond to the temperature dependent phase changes of liposome membrane. Above 15 mol %, capsaicin in the aqueous liposome suspension medium lowers the thermotropic phase transition temperature by about 3 °C, and above 30 mol %, the integrity of the membrane is significantly lost.

  13. The distinctive germinal center phase of IgE+ B lymphocytes limits their contribution to the classical memory response

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The mechanisms involved in the maintenance of memory IgE responses are poorly understood, and the role played by germinal center (GC) IgE+ cells in memory responses is particularly unclear. IgE B cell differentiation is characterized by a transient GC phase, a bias towards the plasma cell (PC) fate,...

  14. Effect of sharp jumps at the edges of phase response curves on synchronization of electrically coupled neuronal oscillators.

    PubMed

    Dodla, Ramana; Wilson, Charles J

    2013-01-01

    We study synchronization phenomenon of coupled neuronal oscillators using the theory of weakly coupled oscillators. The role of sudden jumps in the phase response curve profiles found in some experimental recordings and models on the ability of coupled neurons to exhibit synchronous and antisynchronous behavior is investigated, when the coupling between the neurons is electrical. The level of jumps in the phase response curve at either end, spike width and frequency of voltage time course of the coupled neurons are parameterized using piecewise linear functional forms, and the conditions for stable synchrony and stable antisynchrony in terms of those parameters are computed analytically. The role of the peak position of the phase response curve on phase-locking is also investigated.

  15. Experimental observation of the bifurcation dynamics of an intrinsic localized mode in a driven 1D nonlinear lattice.

    PubMed

    Sato, M; Imai, S; Fujita, N; Nishimura, S; Takao, Y; Sada, Y; Hubbard, B E; Ilic, B; Sievers, A J

    2011-12-01

    Linear response spectra of a driven intrinsic localized mode in a micromechanical array are measured as it approaches two fundamentally different kinds of bifurcation points. A linear phase mode associated with this autoresonant state softens in frequency and its amplitude grows as the upper frequency bifurcation point is approached, similar to the soft-mode kinetic transition for a single driven Duffing resonator. A lower frequency bifurcation point occurs when the four-wave-mixing partner of this same phase mode intercepts the top of the extended wave branch, initiating a second kinetic transition process. PMID:22182091

  16. Abrupt onset of tongue deformation and phase space response of ions in magnetically-confined plasmas

    PubMed Central

    Ida, K.; Kobayashi, T.; Itoh, K.; Yoshinuma, M.; Tokuzawa, T.; Akiyama, T.; Moon, C.; Tsuchiya, H.; Inagaki, S.; Itoh, S.-I.

    2016-01-01

    An abrupt onset of the new tongue-shaped deformation of magnetic surface in magnetized plasmas, which was conjectured in since the 1960s but has not been observed, is experimentally identified just before an abrupt onset of a large-scale collapse event. Two novel properties of the event are identified. First, the transition of symmetry of perturbation (rather than a growth of linearly unstable MHD modes) was found to be a key for the onset of abrupt collapse, i.e., the transition of symmetry gives a new route to the collapse from stable state. Second, as a phase-space response of ions, the distortion from Maxwell-Boltzmann distribution of epithermal ions was observed for the first time. PMID:27796370

  17. Random phase approximation correlation energy using a compact representation for linear response functions: application to solids

    NASA Astrophysics Data System (ADS)

    Kaoui, Fawzi; Rocca, Dario

    2016-01-01

    A new approach was recently presented to compute correlation energies within the random phase approximation using Lanczos chains and an optimal basis set (Rocca 2014 J. Chem. Phys. 140 18A501). This novel method avoids the explicit calculation of conduction states and represents linear response functions on a compact auxiliary basis set obtained from the diagonalization of an approximate dielectric matrix that contains only the kinetic energy contribution. Here, we extend this formalism, originally implemented for molecular systems, to treat periodic solids. In particular, the approximate dielectric matrix used to build the auxiliary basis set is generalized to avoid unphysical negative gaps, that make the model inefficient. The numerical convergence of the method is discussed and the accuracy is demonstrated considering a set including three covalently bonded (C, Si, and SiC) and three weakly bonded (Ne, Ar, and Kr) solids.

  18. Bending the curve: force health protection during the insertion phase of the Ebola outbreak response.

    PubMed

    Bailey, Mark S; Beaton, K; Bowley, D; Eardley, W; Hunt, P; Johnson, S; Round, J; Tarmey, N T; Williams, A

    2016-06-01

    After >10 years of enduring operations in Iraq and Afghanistan, Defence Strategic Direction is returning to a contingency posture. As the first post-Afghanistan operation, in September 2014, a UK Joint Inter-Agency Task Force deployed to Sierra Leone in response to the Ebola virus disease (EVD) epidemic in West Africa. The aims were expanding treatment capacity, assisting with training and supporting host nation resilience. The insertion phase of this deployment created a unique set of challenges for force health protection. In addition to the considerable risk of tropical disease and trauma, deployed personnel faced the risks of working in an EVD epidemic. This report explores how deployed medical assets overcame the difficulties of mounting a short-notice contingent operation in a region of the world with inherent major climatic and health challenges. PMID:26036821

  19. Effect of insulin on the inflammatory and acute phase response after burn injury.

    PubMed

    Jeschke, Marc G; Boehning, Darren F; Finnerty, Celeste C; Herndon, David N

    2007-09-01

    After a severe burn, the liver plays a pivotal role by modulating inflammatory processes, metabolic pathways, immune functions, and the acute phase response. Therefore, liver integrity and function are important for recovery. A thermal injury, however, causes hepatic damage by inducing hepatic edema, fatty infiltration, hepatocyte apoptosis, and metabolic derangements associated with insulin resistance and impaired insulin signaling. In preliminary studies, we found that these pathophysiological processes are related to hepatic inflammation, altered intracellular signaling, and mitochondrial dysfunction. We hypothesize that modulation of these processes with insulin could improve hepatic structure and function and, therefore, outcome of burned and critically ill patients. Insulin administration improves survival and decreases the rate of infections in severely burned and critically ill patients. Here, we show that insulin administration decreases the synthesis of proinflammatory cytokines and signal transcription factors and improves hepatic structure and function after a severe burn injury; insulin also restores hepatic homeostasis and improves hepatic dysfunction postburn via alterations in the signaling cascade.

  20. NASA Environmentally Responsible Aviation Projects Propulsion Technology Phase I Overview and Highlights of Accomplishments

    NASA Technical Reports Server (NTRS)

    Suder, Kenneth L.; Delaat, John C.

    2012-01-01

    The NASA Environmentally Responsible Aviation (ERA) Project is focused on developing and demonstrating integrated systems technologies to TRL 4-6 by 2020 that enable reduced fuel burn, emissions, and noise for futuristic air vehicles. The specific goals aim to simultaneously reduce fuel burn by 50%, reduce Landing and Take-off Nitrous Oxides emissions by 75% relative to the CAEP 6 guidelines, and reduce cumulative noise by 42 Decibels relative to the Stage 4 guidelines. These goals apply to the integrated vehicle and propulsion system and are based on a reference mission of 3000nm flight of a Boeing 777-200 with GE90 engines. This paper will focus primarily on the ERA propulsion technology portfolio, which consists of advanced combustion, propulsor, and core technologies to enable these integrated air vehicle systems goals. An overview of the ERA propulsion technologies will be described and highlights of the results obtained during the first phase of ERA will be presented.

  1. Linear response of light deformed nuclei investigated by self-consistent quasiparticle random-phase approximation

    SciTech Connect

    Losa, C.; Doessing, T.; Pastore, A.; Vigezzi, E.; Broglia, R. A.

    2010-06-15

    We present a calculation of the properties of vibrational states in deformed, axially-symmetric even-even nuclei, within the framework of a fully self-consistent quasiparticle random phase approximation (QRPA). The same Skyrme energy density and density-dependent pairing functionals are used to calculate the mean field and the residual interaction in the particle-hole and particle-particle channels. We have tested our software in the case of spherical nuclei against fully self-consistent calculations published in the literature, finding excellent agreement. We investigate the consequences of neglecting the spin-orbit and Coulomb residual interactions in QRPA. Furthermore we discuss the improvement obtained in the QRPA result associated with the removal of spurious modes. Isoscalar and isovector responses in the deformed {sup 24-26}Mg, {sup 34}Mg isotopes are presented and compared to experimental findings.

  2. A class of reduced-complexity Viterbi detectors for partial response continuous phase modulation

    NASA Astrophysics Data System (ADS)

    Svensson, A.; Sundberg, C.-E.; Aulin, T.

    1984-10-01

    Partial response continuous phase modulation (CPM) gives constant envelope digital modulation schemes with excellent power spectra. Both narrow main lobe and low spectral tails can be achieved. When these signals are detected in an optimum coherent maximum likelihood sequence detector (Viterbi detector), power efficient schemes can also be designed, sometimes at the expense of receiver complexity. This paper describes a general class of simple Viterbi detectors with reduced complexity compared to the optimum case. The key idea is that the approximate receiver is based on a less complex CPM scheme than the transmitted scheme. The asymptotically optimum reduced-complexity receiver is found for a variety of transmitted schemes and various complexity reduction factors, for a specific class of receivers and modulation indexes. A new distance measure is introduced for the performance analysis. Smooth schemes based on raised cosine pulses are analyzed and simulated for the case of simplified reception. A graceful performance degradation occurs with the reduction of complexity.

  3. Western Wind and Solar Integration Study Phase 3 – Frequency Response and Transient Stability

    SciTech Connect

    Miller, N. W.; Shao, M.; Pajic, S.; D'Aquila, R.

    2014-12-01

    Power system operators and utilities worldwide have concerns about the impact of high-penetration wind and solar generation on electric grid reliability (EirGrid 2011b, Hydro-Quebec 2006, ERCOT 2010). The stability of North American grids under these conditions is a particular concern and possible impediment to reaching future renewable energy goals. Phase 3 of the Western Wind and Solar Integration Study (WWSIS-3) considers a 33% wind and solar annual energy penetration level that results in substantial changes to the characteristics of the bulk power system, including different power flow patterns, different commitment and dispatch of existing synchronous generation, and different dynamic behavior of wind and solar generation. WWSIS-3 evaluates two specific aspects of fundamental frequency system stability: frequency response and transient stability.

  4. Structure, phases, and mechanical response of Ti-alloy bioactive glass composite coatings.

    PubMed

    Nelson, G M; Nychka, J A; McDonald, A G

    2014-03-01

    Porous titanium alloy-bioactive glass composite coatings were manufactured via the flame spray deposition process. The porous coatings, targeted for orthodontic and bone-fixation applications, were made from bioactive glass (45S5) powder blended with either commercially pure titanium (Cp-Ti) or Ti-6Al-4V alloy powder. Two sets of spray conditions, two metallic particle size distributions, and two glass particle size distributions were used for this study. Negative control coatings consisting of pure Ti-6Al-4V alloy or Cp-Ti were sprayed under both conditions. The as-sprayed coatings were characterized through quantitative optical cross-sectional metallography, X-ray diffraction (XRD), and ASTM Standard C633 tensile adhesion testing. Determination of the porosity and glassy phase distribution was achieved by using image analysis in accordance with ASTM Standard E2109. Theoretical thermodynamic and heat transfer modeling was conducted to explain experimental observations. Thermodynamic modeling was performed to estimate the flame temperature and chemical environment for each spray condition and a lumped capacitance heat transfer model was developed to estimate the temperatures attained by each particle. These models were used to establish trends among the choice of alloy, spray condition, and particle size distribution. The deposition parameters, alloy composition, and alteration of the feedstock powder size distribution had a significant effect on the coating microstructure, porosity, phases present, mechanical response, and theoretical particle temperatures that were attained. The most promising coatings were the Ti-6Al-4V-based composite coatings, which had bond strength of 20±2MPa (n=5) and received reinforcement and strengthening from the inclusion of a glassy phase. It was shown that the use of the Ti-6Al-4V-bioactive glass composite coatings may be a superior choice due to the possible osteoproductivity from the bioactive glass, the potential ability to

  5. Effect of phase response curve skewness on synchronization of electrically coupled neuronal oscillators.

    PubMed

    Dodla, Ramana; Wilson, Charles J

    2013-10-01

    We investigate why electrically coupled neuronal oscillators synchronize or fail to synchronize using the theory of weakly coupled oscillators. Stability of synchrony and antisynchrony is predicted analytically and verified using numerical bifurcation diagrams. The shape of the phase response curve (PRC), the shape of the voltage time course, and the frequency of spiking are freely varied to map out regions of parameter spaces that hold stable solutions. We find that type 1 and type 2 PRCs can hold both synchronous and antisynchronous solutions, but the shape of the PRC and the voltage determine the extent of their stability. This is achieved by introducing a five-piecewise linear model to the PRC and a three-piecewise linear model to the voltage time course, and then analyzing the resultant eigenvalue equations that determine the stability of the phase-locked solutions. A single time parameter defines the skewness of the PRC, and another single time parameter defines the spike width and frequency. Our approach gives a comprehensive picture of the relation of the PRC shape, voltage time course, and stability of the resultant synchronous and antisynchronous solutions.

  6. Signatures of topological phase transition in 3 d topological insulators from dynamical axion response

    NASA Astrophysics Data System (ADS)

    Makhfudz, Imam

    2016-04-01

    Axion electrodynamics, first proposed in the context of particle physics, manifests itself in condensed matter physics in the topological field theory description of 3 d topological insulators and gives rise to magnetoelectric effect, where applying magnetic (electric) field B (E ) induces polarization (magnetization) p (m ) . We use linear response theory to study the associated topological current using the Fu-Kane-Mele model of 3 d topological insulators in the presence of time-dependent uniform weak magnetic field. By computing the dynamical current susceptibility χij jpjp(ω ) , we discover from its static limit an `order parameter' of the topological phase transition between weak topological (or ordinary) insulator and strong topological insulator, found to be continuous. The χij jpjp(ω ) shows a sign-changing singularity at a critical frequency with suppressed strength in the topological insulating state. Our results can be verified in current noise experiment on 3 d TI candidate materials for the detection of such topological phase transition.

  7. Anti-CD163-dexamethasone conjugate inhibits the acute phase response to lipopolysaccharide in rats

    PubMed Central

    Thomsen, Karen Louise; Møller, Holger Jon; Graversen, Jonas Heilskov; Magnusson, Nils E; Moestrup, Søren K; Vilstrup, Hendrik; Grønbæk, Henning

    2016-01-01

    AIM: To study the effect of a new anti-CD163-dexamethasone conjugate targeting activated macrophages on the hepatic acute phase response in rats. METHODS: Wistar rats were injected intravenous with either the CD163 targeted dexamethasone-conjugate (0.02 mg/kg) or free dexamethasone (0.02 or 1 mg/kg) 24 h prior to lipopolysaccharide (LPS) (2.5 mg/kg intraperitoneal). We measured plasma concentrations of tumour necrosis factor-α (TNF-α) and interleukin 6 (IL-6) 2 h post-LPS and liver mRNAs and serum concentrations of the rat acute phase protein α-2-macroglobulin (α-2-M) 24 h after LPS. Also, plasma concentrations of alanine aminotransferase and bilirubin were measured at termination of the study. Spleen weight served as an indicator of systemic steroid effects. RESULTS: The conjugate halved the α-2-M liver mRNA (3.3 ± 0.6 vs 6.8 ± 1.1, P < 0.01) and serum protein (201 ± 48 μg/mL vs 389 ± 67 μg/mL, P = 0.04) after LPS compared to low dose dexamethasone treated animals, while none of the free dexamethasone doses had an effect on liver mRNA or serum levels of α-2-M. Also, the conjugate reduced TNF-α (7208 ± 1977 pg/mL vs 21583 ± 7117 pg/mL, P = 0.03) and IL-6 (15685 ± 3779 pg/mL vs 25715 ± 4036 pg/mL, P = 0.03) compared to the low dose dexamethasone. The high dose dexamethasone dose decreased the spleen weight (421 ± 11 mg vs 465 ± 12 mg, P < 0.05) compared to controls, an effect not seen in any other group. CONCLUSION: Low-dose anti-CD163-dexamethasone conjugate effectively decreased the hepatic acute phase response to LPS. This indicates an anti-inflammatory potential of the conjugate in vivo. PMID:27330681

  8. Chelation efficacy and erythroid response during deferasirox treatment in patients with myeloproliferative neoplasms in fibrotic phase.

    PubMed

    Latagliata, Roberto; Montagna, Chiara; Porrini, Raffaele; Di Veroli, Ambra; Leonetti, Sabrina Crescenzi; Niscola, Pasquale; Ciccone, Fabrizio; Spadea, Antonio; Breccia, Massimo; Maurillo, Luca; Rago, Angela; Spirito, Francesca; Cedrone, Michele; De Muro, Marianna; Montanaro, Marco; Andriani, Alessandro; Bagnato, Antonino; Montefusco, Enrico; Alimena, Giuliana

    2016-06-01

    At present, very few data are available on deferasirox (DFX) in the treatment of patients with Philadelphia-negative myeloproliferative neoplasms in fibrotic phase (FP-MPN) and transfusion dependence. To address this issue, a retrospective analysis of 28 patients (22 male and 6 female) with FP-MPN and iron overload secondary to transfusion dependence was performed, based on patients enrolled in the database of our regional cooperative group who received treatment with DFX. DFX was started after a median interval from diagnosis of 12.8 months (IR 7.1-43.1) with median ferritin values of 1415 ng/mL (IR 1168-1768). Extra-hematological toxicity was reported in 16 of 28 patients (57.1%), but only two patients discontinued treatment due to toxicity. Among 26 patients evaluable for response (≥6 months of treatment), after a median treatment period of 15.4 months (IR 8.1-22.3), 11 patients (42.3%) achieved a stable and consistent reduction in ferritin levels <1000 ng/mL. As for hematological improvement, 6 of 26 patients (23%) showed a persistent (>3 months) rise of Hb levels >1.5 g/dL, with disappearance of transfusion dependence in four cases. Treatment with DFX is feasible and effective in FP-MPN with iron overload. Moreover, in this setting, an erythroid response can occur in a significant proportion of patients.

  9. Acute phase protein and antioxidant responses in dogs with experimental acute monocytic ehrlichiosis treated with rifampicin.

    PubMed

    Karnezi, Dimitra; Ceron, Jose J; Theodorou, Konstantina; Leontides, Leonidas; Siarkou, Victoria I; Martinez, Silvia; Tvarijonaviciute, Asta; Harrus, Shimon; Koutinas, Christos K; Pardali, Dimitra; Mylonakis, Mathios E

    2016-02-29

    There is currently lack of information on the changes of acute phase proteins (APP) and antioxidant markers and their clinical relevance as treatment response indicators in canine monocytic ehrlichiosis (CME). The objective of this study was to investigate the patterns of C-reactive protein (CRP), haptoglobin (Hp), ferritin and paraoxonase-1 (PON-1) during treatment of dogs with acute CME with rifampicin. Blood serum samples from ten Beagle dogs with experimental acute CME were retrospectively examined. Five dogs (Group A) were treated with rifampicin (10mg/Kg/24h), per os, for 3 weeks and 5 dogs (Group B) received no treatment (infected controls). Two Beagle dogs served as uninfected controls. Blood serum samples were serially examined prior to Ehrlichia canis inoculation and on post-inoculation days 14, 21, 28, 35 and 42. Significant changes of CRP, Hp, ferritin and PON-1 values were found in the majority of infected dogs. However, their concentrations did not differ between the two groups during the treatment observation period. The results of this study indicate that although several APP and PON-1 tend to significantly change in the majority of dogs with acute CME, they were of limited clinical relevance as treatment response indicators in this experimental setting.

  10. Peripherally restricted acute phase response to a viral mimic alters hippocampal gene expression.

    PubMed

    Michalovicz, Lindsay T; Konat, Gregory W

    2014-03-01

    We have previously shown that peripherally restricted acute phase response (APR) elicited by intraperitoneal (i.p.) injection of a viral mimic, polyinosinic-polycytidylic acid (PIC), renders the brain hypersusceptible to excitotoxic insult as seen from profoundly exacerbated kainic acid (KA)-induced seizures. In the present study, we found that this hypersusceptibility was protracted for up to 72 h. RT-PCR profiling of hippocampal gene expression revealed rapid upregulation of 23 genes encoding cytokines, chemokines and chemokine receptors generally within 6 h after PIC challenge. The expression of most of these genes decreased by 24 h. However, two chemokine genes, i.e., Ccl19 and Cxcl13 genes, as well as two chemokine receptor genes, Ccr1 and Ccr7, remained upregulated for 72 h suggesting their possible involvement in the induction and sustenance of seizure hypersusceptibility. Also, 12 genes encoding proteins related to glutamatergic and GABAergic neurotransmission featured initial upregulation or downregulation followed by gradual normalization. The upregulation of the Gabrr3 gene remained upregulated at 72 h, congruent with its plausible role in the hypersusceptible phenotype. Moreover, the expression of ten microRNAs (miRs) was rapidly affected by PIC challenge, but their levels generally exhibited oscillating profiles over the time course of seizure hypersusceptibility. These results indicate that protracted seizure susceptibility following peripheral APR is associated with a robust polygenic response in the hippocampus. PMID:24363211

  11. Acute phase protein and antioxidant responses in dogs with experimental acute monocytic ehrlichiosis treated with rifampicin.

    PubMed

    Karnezi, Dimitra; Ceron, Jose J; Theodorou, Konstantina; Leontides, Leonidas; Siarkou, Victoria I; Martinez, Silvia; Tvarijonaviciute, Asta; Harrus, Shimon; Koutinas, Christos K; Pardali, Dimitra; Mylonakis, Mathios E

    2016-02-29

    There is currently lack of information on the changes of acute phase proteins (APP) and antioxidant markers and their clinical relevance as treatment response indicators in canine monocytic ehrlichiosis (CME). The objective of this study was to investigate the patterns of C-reactive protein (CRP), haptoglobin (Hp), ferritin and paraoxonase-1 (PON-1) during treatment of dogs with acute CME with rifampicin. Blood serum samples from ten Beagle dogs with experimental acute CME were retrospectively examined. Five dogs (Group A) were treated with rifampicin (10mg/Kg/24h), per os, for 3 weeks and 5 dogs (Group B) received no treatment (infected controls). Two Beagle dogs served as uninfected controls. Blood serum samples were serially examined prior to Ehrlichia canis inoculation and on post-inoculation days 14, 21, 28, 35 and 42. Significant changes of CRP, Hp, ferritin and PON-1 values were found in the majority of infected dogs. However, their concentrations did not differ between the two groups during the treatment observation period. The results of this study indicate that although several APP and PON-1 tend to significantly change in the majority of dogs with acute CME, they were of limited clinical relevance as treatment response indicators in this experimental setting. PMID:26854345

  12. Systematic Studies of Phase Transitions in Thermo-Responsive Polymers Used in Targeted Drug Delivery

    NASA Astrophysics Data System (ADS)

    Bradley, Janae; Denmark, Daniel; Witanachchi, Sarath

    2015-03-01

    Thermo-responsive polymers such as poly-N-isopropylacrylamide (PNIPAM) can undergo reversible phase transitions in aqueous solutions under varying temperatures. They are ideal candidates for the polymer shell of a targeted drug delivery capsule. Concentration and pH can affect the lower critical solution temperature (LCST) of the PNIPAM polymer and its physical properties. In this work, a systematic study of the factors that influence the LCST of the PNIPAM polymer mixed with Fe3O4 nanoparticles (MNPs) during thermal bath heating is presented. A series of PNIPAM solutions with varying concentrations of PNIPAM with MNPs were prepared and characterized using scanning electron microscopy. In-situ transmission measurements were used to determine the LCST of PNIPAM concentrations. A systematic decrease in the LCST was observed as the concentration of PNIPAM was increased. In addition, the impact of pH on the LCST of PNIPAM was examined by increasing the basicity of the PNIPAM solutions by adding adjusted KOH pellets. An increase in the thermal stability of the LCST was observed when the basicity of the PNIPAM solution was increased. The results from this study provide valuable information towards using these thermo-responsive polymers in targeted drug delivery. Principal Investigator

  13. Chelation efficacy and erythroid response during deferasirox treatment in patients with myeloproliferative neoplasms in fibrotic phase.

    PubMed

    Latagliata, Roberto; Montagna, Chiara; Porrini, Raffaele; Di Veroli, Ambra; Leonetti, Sabrina Crescenzi; Niscola, Pasquale; Ciccone, Fabrizio; Spadea, Antonio; Breccia, Massimo; Maurillo, Luca; Rago, Angela; Spirito, Francesca; Cedrone, Michele; De Muro, Marianna; Montanaro, Marco; Andriani, Alessandro; Bagnato, Antonino; Montefusco, Enrico; Alimena, Giuliana

    2016-06-01

    At present, very few data are available on deferasirox (DFX) in the treatment of patients with Philadelphia-negative myeloproliferative neoplasms in fibrotic phase (FP-MPN) and transfusion dependence. To address this issue, a retrospective analysis of 28 patients (22 male and 6 female) with FP-MPN and iron overload secondary to transfusion dependence was performed, based on patients enrolled in the database of our regional cooperative group who received treatment with DFX. DFX was started after a median interval from diagnosis of 12.8 months (IR 7.1-43.1) with median ferritin values of 1415 ng/mL (IR 1168-1768). Extra-hematological toxicity was reported in 16 of 28 patients (57.1%), but only two patients discontinued treatment due to toxicity. Among 26 patients evaluable for response (≥6 months of treatment), after a median treatment period of 15.4 months (IR 8.1-22.3), 11 patients (42.3%) achieved a stable and consistent reduction in ferritin levels <1000 ng/mL. As for hematological improvement, 6 of 26 patients (23%) showed a persistent (>3 months) rise of Hb levels >1.5 g/dL, with disappearance of transfusion dependence in four cases. Treatment with DFX is feasible and effective in FP-MPN with iron overload. Moreover, in this setting, an erythroid response can occur in a significant proportion of patients. PMID:26277477

  14. Spatial Reasoning With Multiple Intrinsic Frames of Reference

    PubMed Central

    Tamborello, Franklin P; Sun, Yanlong; Wang, Hongbin

    2016-01-01

    Establishing and updating spatial relationships between objects in the environment is vital to maintaining situation awareness and supporting many socio-spatial tasks. In a complex environment, people often need to utilize multiple reference systems that are intrinsic to different objects (intrinsic frame of reference, IFOR), but these IFORs may conflict with each other in one or more ways. Current spatial cognition theories do not adequately address how people handle multi-IFOR reasoning problems. Two experiments manipulated relative orientations of two task-relevant objects with intrinsic axes of orientation as well as their relative task salience. Response times (RTs) decreased with increasing salience of the targeted IFOR. In addition, RTs increased as a consequence of intrinsic orientation conflict, but not by amount of orientation difference. The results suggest that people encounter difficulties when they have to process two conflicting IFOR representations, and that they seem to prioritize processing of each IFOR by salience. PMID:21768066

  15. Acute Phase Responses to Novel, Investigational Vaccines in Toxicology Studies: The Relationship Between C-Reactive Protein and Other Acute Phase Proteins.

    PubMed

    Green, Martin D

    2015-01-01

    The objective of this study was to determine the effects of investigational vaccine candidates on acute-phase proteins (APPs) as determined in GLP toxicology studies. Sixty-four GLP toxicity studies, which were submitted to the Food and Drug Administration from 2008 to 2012 in support of proposed clinical investigations, were reviewed and entered into a database. These studies employed the intramuscular route of injection and were conducted using New Zealand White rabbits. A retrospective review of these GLP toxicity studies was conducted to evaluate the changes in plasma levels of C-reactive protein (CRP), fibrinogen, and albumin as APPs following the administration of various investigational vaccines. The incidence and intensity of responses associated with acute-phase responses both positive and negative were observed to increase in animals when treated with vaccines containing more potent immunological components such as novel adjuvants that activate Toll-like receptors in the investigational vaccine products. Changes in plasma levels of CRP were prominent among these responses and provided a basis to propose a classification scheme of H, M, L, and N responding groups. These changes in plasma proteins reflect an activation of the acute-phase response and indicate increasing levels of systemic inflammation, which potentially may be correlated with important clinical adverse events.

  16. HIV-specific humoral responses benefit from stronger prime in phase Ib clinical trial

    PubMed Central

    Bart, Pierre-Alexandre; Huang, Yunda; Karuna, Shelly T.; Chappuis, Samuel; Gaillard, Julien; Kochar, Nidhi; Shen, Xiaoying; Allen, Mary A.; Ding, Song; Hural, John; Liao, Hua-Xin; Haynes, Barton F.; Graham, Barney S.; Gilbert, Peter B.; McElrath, M. Juliana; Montefiori, David C.; Tomaras, Georgia D.; Pantaleo, Giuseppe; Frahm, Nicole

    2014-01-01

    BACKGROUND. Vector prime-boost immunization strategies induce strong cellular and humoral immune responses. We examined the priming dose and administration order of heterologous vectors in HIV Vaccine Trials Network 078 (HVTN 078), a randomized, double-blind phase Ib clinical trial to evaluate the safety and immunogenicity of heterologous prime-boost regimens, with a New York vaccinia HIV clade B (NYVAC-B) vaccine and a recombinant adenovirus 5–vectored (rAd5-vectored) vaccine. METHODS. NYVAC-B included HIV-1 clade B Gag-Pol-Nef and gp120, while rAd5 included HIV-1 clade B Gag-Pol and clades A, B, and C gp140. Eighty Ad5-seronegative subjects were randomized to receive 2 × NYVAC-B followed by 1 × 1010 PFU rAd5 (NYVAC/Ad5hi); 1 × 108 PFU rAd5 followed by 2 × NYVAC-B (Ad5lo/NYVAC); 1 × 109 PFU rAd5 followed by 2 × NYVAC-B (Ad5med/NYVAC); 1 × 1010 PFU rAd5 followed by 2 × NYVAC-B (Ad5hi/NYVAC); or placebo. Immune responses were assessed 2 weeks after the final vaccination. Intracellular cytokine staining measured T cells producing IFN-γ and/or IL-2; cross-clade and epitope-specific binding antibodies were determined; and neutralizing antibodies (nAbs) were assessed with 6 tier 1 viruses. RESULTS. CD4+ T cell response rates ranged from 42.9% to 93.3%. NYVAC/Ad5hi response rates (P ≤ 0.01) and magnitudes (P ≤ 0.03) were significantly lower than those of other groups. CD8+ T cell response rates ranged from 65.5% to 85.7%. NYVAC/Ad5hi magnitudes were significantly lower than those of other groups (P ≤ 0.04). IgG response rates to the group M consensus gp140 were 89.7% for NYVAC/Ad5hi and 21.4%, 84.6%, and 100% for Ad5lo/NYVAC, Ad5med/NYVAC, and Ad5hi/NYVAC, respectively, and were similar for other vaccine proteins. Overall nAb responses were low, but aggregate responses appeared stronger for Ad5med/NYVAC and Ad5hi/NYVAC than for NYVAC/Ad5hi. CONCLUSIONS. rAd5 prime followed by NYVAC boost is superior to the reverse regimen for both vaccine

  17. Intrinsic Motivation in Physical Education

    ERIC Educational Resources Information Center

    Davies, Benjamin; Nambiar, Nathan; Hemphill, Caroline; Devietti, Elizabeth; Massengale, Alexandra; McCredie, Patrick

    2015-01-01

    This article describes ways in which educators can use Harter's perceived competence motivation theory, the achievement goal theory, and self-determination theory to develop students' intrinsic motivation to maintain physical fitness, as demonstrated by the Sound Body Sound Mind curriculum and proven effective by the 2013 University of…

  18. The onset of the progression of acute phase response mechanisms induced by extreme impacts can be followed by the decrease in blood levels of positive acute phase proteins.

    NASA Astrophysics Data System (ADS)

    Larina, Olga; Bekker, Anna

    Studies performed at space flights and earth-based simulation models detected the plasma indices of acute phase reaction (APR), i.e. the increase of APR cytokine mediators and alterations in the production of blood acute phase proteins (APP) at the initial stages of adaptation to altered gravity conditions. Acute phase response is the principal constituent of the functional activity of innate immunity system. Changes in plasma APPs contents are considered to serve the restoration of homeostasis state. According to trends of their concentration shifts at the evolving of acute phase reaction APPs are denoted as positive, neutral, or negative. Plasma concentrations of positive acute phase proteins α1-acid glycoprotein (α1-AGP), α1-antitrypsin (α1-AT), and neutral α2-macroglobulin (α2-M) were measured in human study at 12-hour antiorthostatic position (AOP) with 15° head down tilt and hypoxia experiments at 14% oxygen in pressure chamber. Both of these impacts were shown to produce alterations in the APP levels indicative for acute phase response. Nevertheless, in AOP experiment noticeable decrease in α1-AGP concentration occurred by hour 12, and even more pronounced decline of α1-AGP and α1-AT were found on hypoxia hours 12 and 36. Acute phase proteins α1-AGP and α2-M possess the features of proteinase inhibitors. This function is implemented by the formation of complexes with the molecules of proteolytic enzymes which subsequently are removed from the blood flow. Transient decrease in plasma concentrations of protease inhibitors on early phases of APR development was reported to result from the growth of plasma protease activity due to cathepsin release from activated leukocytes, which had not yet been compensated by enhanced APP synthesis. Being a carrier protein for positively charged and neutral substances, α1-AGP shows pronounced elevation in its blood content during APR development. As assumed, it is required for the transportation of the increased

  19. Photic entrainment of Period mutant mice is predicted from their phase response curves

    PubMed Central

    Pendergast, Julie S.; Friday, Rio C.; Yamazaki, Shin

    2010-01-01

    A fundamental property of circadian clocks is that they entrain to environmental cues. The circadian genes, Period1 and Period2, are involved in entrainment of the mammalian circadian system. To investigate the roles of the Period genes in photic entrainment, we constructed phase response curves (PRC) to light pulses for C57BL/6J wild-type, Per1−/−, Per2−/−, and Per3−/− mice and tested whether the PRCs accurately predict entrainment to non-24 light-dark cycles (T-cycles) and constant light (LL). The PRCs of wild-type and Per3−/− mice are similar in shape and amplitude and have relatively large delay zones and small advance zones, resulting in successful entrainment to T26, but not T21, with similar phase angles. Per1−/− mice have a high-amplitude PRC, resulting in entrainment to a broad range of T-cycles. Per2−/− mice also entrain to a wide range of T-cycles because the advance portion of their PRC is larger than wild-types. Period aftereffects following entrainment to T-cycles were similar among all genotypes. We found that the ratio of the advance portion to the delay portion of the PRC accurately predicts the lengthening of the period of the activity rhythm in LL. Wild-type, Per1−/−, and Per3−/− mice had larger delay zones than advance zones and lengthened (>24hrs) periods in LL, while Per2−/− mice had delay and advance zones that were equal in size and no period lengthening in LL. Together, these results demonstrate that PRCs are powerful tools for predicting and understanding photic entrainment of circadian mutant mice. PMID:20826680

  20. Responses of a top and a meso predator and their prey to moon phases.

    PubMed

    Penteriani, Vincenzo; Kuparinen, Anna; del Mar Delgado, Maria; Palomares, Francisco; López-Bao, José Vicente; Fedriani, José María; Calzada, Javier; Moreno, Sacramento; Villafuerte, Rafael; Campioni, Letizia; Lourenço, Rui

    2013-11-01

    We compared movement patterns and rhythms of activity of a top predator, the Iberian lynx Lynx pardinus, a mesopredator, the red fox Vulpes vulpes, and their shared principal prey, the rabbit Oryctolagus cuniculus, in relation to moon phases. Because the three species are mostly nocturnal and crepuscular, we hypothesized that the shared prey would reduce its activity at most risky moon phases (i.e. during the brightest nights), but that fox, an intraguild prey of lynx, would avoid lynx activity peaks at the same time. Rabbits generally moved further from their core areas on darkest nights (i.e. new moon), using direct movements which minimize predation risk. Though rabbits responded to the increased predation risk by reducing their activity during the full moon, this response may require several days, and the moon effect we observed on the rabbits had, therefore, a temporal gap. Lynx activity patterns may be at least partially mirroring rabbit activity: around new moons, when rabbits moved furthest and were more active, lynxes reduced their travelling distances and their movements were concentrated in the core areas of their home ranges, which generally correspond to areas of high density of rabbits. Red foxes were more active during the darkest nights, when both the conditions for rabbit hunting were the best and lynxes moved less. On the one hand, foxes increased their activity when rabbits were further from their core areas and moved with more discrete displacements; on the other hand, fox activity in relation to the moon seemed to reduce dangerous encounters with its intraguild predator. PMID:23579570

  1. Responses of a top and a meso predator and their prey to moon phases.

    PubMed

    Penteriani, Vincenzo; Kuparinen, Anna; del Mar Delgado, Maria; Palomares, Francisco; López-Bao, José Vicente; Fedriani, José María; Calzada, Javier; Moreno, Sacramento; Villafuerte, Rafael; Campioni, Letizia; Lourenço, Rui

    2013-11-01

    We compared movement patterns and rhythms of activity of a top predator, the Iberian lynx Lynx pardinus, a mesopredator, the red fox Vulpes vulpes, and their shared principal prey, the rabbit Oryctolagus cuniculus, in relation to moon phases. Because the three species are mostly nocturnal and crepuscular, we hypothesized that the shared prey would reduce its activity at most risky moon phases (i.e. during the brightest nights), but that fox, an intraguild prey of lynx, would avoid lynx activity peaks at the same time. Rabbits generally moved further from their core areas on darkest nights (i.e. new moon), using direct movements which minimize predation risk. Though rabbits responded to the increased predation risk by reducing their activity during the full moon, this response may require several days, and the moon effect we observed on the rabbits had, therefore, a temporal gap. Lynx activity patterns may be at least partially mirroring rabbit activity: around new moons, when rabbits moved furthest and were more active, lynxes reduced their travelling distances and their movements were concentrated in the core areas of their home ranges, which generally correspond to areas of high density of rabbits. Red foxes were more active during the darkest nights, when both the conditions for rabbit hunting were the best and lynxes moved less. On the one hand, foxes increased their activity when rabbits were further from their core areas and moved with more discrete displacements; on the other hand, fox activity in relation to the moon seemed to reduce dangerous encounters with its intraguild predator.

  2. Characterization of submillisecond response optical addressing phase modulator based on low light scattering polymer network liquid crystal

    SciTech Connect

    Xiangjie, Zhao E-mail: zxjdouble@gmail.com; Cangli, Liu; Jiazhu, Duan; Dayong, Zhang; Yongquan, Luo

    2015-01-07

    Optically addressed conventional nematic liquid crystal spatial light modulator has attracted wide research interests. But the slow response speed limited its further application. In this paper, polymer network liquid crystal (PNLC) was proposed to replace the conventional nematic liquid crystal to enhance the response time to the order of submillisecond. The maximum light scattering of the employed PNLC was suppressed to be less than 2% at 1.064 μm by optimizing polymerization conditions and selecting large viscosity liquid crystal as solvent. The occurrence of phase ripple phenomenon due to electron diffusion and drift in photoconductor was found to deteriorate the phase modulation effect of the optical addressed PNLC phase modulator. The wavelength effect and AC voltage frequency effect on the on state dynamic response of phase change was investigated by experimental methods. These effects were interpreted by electron diffusion and drift theory based on the assumption that free electron was inhomogeneously distributed in accordance with the writing beam intensity distribution along the incident direction. The experimental results indicated that the phase ripple could be suppressed by optimizing the wavelength of the writing beam and the driving AC voltage frequency when varying the writing beam intensity to generate phase change in 2π range. The modulation transfer function was also measured.

  3. Linear response and Berry curvature in two-dimensional topological phases

    NASA Astrophysics Data System (ADS)

    Bradlyn, Barry J.

    cannot contribute to low-temperature thermoelectric transport other than the ordinary Hall conductivity; the other thermoelectric effects (if they occur) are thus purely edge effects. The stress response to time-dependent strains is given by the Hall viscosity, which is robust against perturbations and related to the spin current. Finally, we address the issue of calculating the topological central charge from bulk wavefunctions for a topological phase. Using the form of the topological terms in the induced action, we show that we can calculate the various coefficients of these terms as Berry curvatures associated to certain metric and electromagnetic vector potential perturbations. We carry out this computation explicitly for quantum Hall trial wavefunctions that can be represented as conformal blocks in a chiral conformal field theory (CFT). These calculations make use of the gauge and gravitational anomalies in the underlying chiral CFT.

  4. Tidal Response and Stability of Two-phase Media: Implications for Io, Europa and Titan

    NASA Astrophysics Data System (ADS)

    Stevenson, D. J.

    2002-12-01

    Most models of planets and satellites assume homogeneous or layered media in which each layer is one phase. However, real planets and satellites may have two phase media (e.g., solid plus liquid) throughout a significant portion of their interior. I concentrate here on percolation media (a deformable solid matrix with an interconnected fluid-filled pore space that allows fluid redistribution under the action of stress). In such a medium, the phases are individually incompressible but Darcy flow from one region to another could lead to an overall effective compressibility, pumping of liquid in spite of the overall tendency towards gravitational separation, and possibly an additional heat transfer mechanism. In particular, I answer here the following questions, which appear to be unrelated but are in fact closely related: (1) Could a partially molten asthenosphere of Io behave like a compressible medium and allow decoupling of the lithosphere from the deeper interior? (2) Could tidally -driven flow of water in the ice of Europa's crust lead to net upward transfer of liquid water? (3) Can tidal response of an ethane/methane-bearing outer layer of water ice on Titan (i.e., a hidden ocean) satisfy the requirement that the large orbital eccentricity persist over geologic time? The answers are (1) No. (2) Maybe. (3) Yes. The common factors in treating these problems are: (a)The comparison of tidal stress to the stress associated with the hydrostatic head arising from a density difference of solid and liquid over an interesting distance (e.g., 10km). Typically, these two stresses are comparable. (b)The compaction length which is the scale below which viscous stresses of a deforming solid matrix are more important in determining flow than the simple Darcy flow formula. This is typically small (e.g., 10km or less) except in outermost regions (e.g. Titan). (c) The tidally driven Darcy flux (expressed as a velocity) in comparison to the velocity of time-varying equipotentials

  5. c-Cbl-mediated degradation of TRAIL receptors is responsible for the development of the early phase of TRAIL resistance

    PubMed Central

    Song, Jae J.; Szczepanski, Miroslaw Jerzy; Kim, So Young; Kim, Joo-Hang; An, Jee Young; Kwon, Yong Tae; Alcala, Marco A.; Bartlett, David L.; Lee, Yong J.

    2010-01-01

    We previously reported two modes of development of acquired TRAIL resistance: early phase and late phase [1]. In these studies, we observed that greater Akt activity and the expression of Bcl-xL were related mainly to the late phase of acquired TRAIL resistance. Recently we became aware of a possible mechanism of early phase TRAIL resistance development through internalization and degradation of TRAIL receptors (DR4 and DR5). Our current studies demonstrate that TRAIL receptors rapidly diminish at the membrane as well as the cytoplasm within four hours after TRAIL exposure, but recover completely after one or two days. Our studies also reveal that Cbl, a ubiquitously expressed cytoplasmic adaptor protein, is responsible for the rapid degradation of TRAIL receptors; Cbl binds to them and induces mono-ubiquitination of these receptors concurrent with their degeneration soon after TRAIL exposure, creating the early phase of acquired TRAIL resistance. PMID:19932172

  6. Intrinsic Josephson Junctions with Intermediate Damping

    NASA Astrophysics Data System (ADS)

    Warburton, Paul A.; Saleem, Sajid; Fenton, Jon C.; Speller, Susie; Grovenor, Chris R. M.

    2011-03-01

    In cuprate superconductors, adjacent cuprate double-planes are intrinsically Josephson-coupled. For bias currents perpendicular to the planes, the current-voltage characteristics correspond to those of an array of underdamped Josephson junctions. We will discuss our experiments on sub-micron Tl-2212 intrinsic Josephson junctions (IJJs). The dynamics of the IJJs at the plasma frequency are moderately damped (Q ~ 8). This results in a number of counter-intuitive observations, including both a suppression of the effect of thermal fluctuations and a shift of the skewness of the switching current distributions from negative to positive as the temperature is increased. Simulations confirm that these phenomena result from repeated phase slips as the IJJ switches from the zero-voltage to the running state. We further show that increased dissipation counter-intuitively increases the maximum supercurrent in the intermediate damping regime (PRL vol. 103, art. no. 217002). We discuss the role of environmental dissipation on the dynamics and describe experiments with on-chip lumped-element passive components in order control the environment seen by the IJJs. Work supported by EPSRC.

  7. A robust optimization model for distribution and evacuation in the disaster response phase

    NASA Astrophysics Data System (ADS)

    Fereiduni, Meysam; Shahanaghi, Kamran

    2016-10-01

    Natural disasters, such as earthquakes, affect thousands of people and can cause enormous financial loss. Therefore, an efficient response immediately following a natural disaster is vital to minimize the aforementioned negative effects. This research paper presents a network design model for humanitarian logistics which will assist in location and allocation decisions for multiple disaster periods. At first, a single-objective optimization model is presented that addresses the response phase of disaster management. This model will help the decision makers to make the most optimal choices in regard to location, allocation, and evacuation simultaneously. The proposed model also considers emergency tents as temporary medical centers. To cope with the uncertainty and dynamic nature of disasters, and their consequences, our multi-period robust model considers the values of critical input data in a set of various scenarios. Second, because of probable disruption in the distribution infrastructure (such as bridges), the Monte Carlo simulation is used for generating related random numbers and different scenarios; the p-robust approach is utilized to formulate the new network. The p-robust approach can predict possible damages along pathways and among relief bases. We render a case study of our robust optimization approach for Tehran's plausible earthquake in region 1. Sensitivity analysis' experiments are proposed to explore the effects of various problem parameters. These experiments will give managerial insights and can guide DMs under a variety of conditions. Then, the performances of the "robust optimization" approach and the "p-robust optimization" approach are evaluated. Intriguing results and practical insights are demonstrated by our analysis on this comparison.

  8. What is intrinsic atopic dermatitis?

    PubMed

    Roguedas-Contios, Anne-Marie; Misery, Laurent

    2011-12-01

    Many authors favor a distinction between the extrinsic and intrinsic forms of atopic dermatitis. In this review, the controversy is discussed and several definitions are presented. After reviewing many papers on this topic, it is our opinion that it is useful to separate the intrinsic and extrinsic forms of atopic dermatitis or atopic eczema and atopiform dermatitis because the pathophysiology appears to be different between them. However, these terms require concrete definition and clarification of the distinction between these two concepts. This debate is a new step in the history of atopic dermatitis. It is possible that a single patient could suffer from one form and then from another but genetic differences suggest that two types could really exist.

  9. Radiation-induced p53 protein response in the A549 cell line is culture growth-phase dependent

    SciTech Connect

    Johnson, N.F.; Gurule, D.M.; Carpenter, T.R.

    1995-12-01

    One role of the p53 tumor suppressor protein has been recently revealed. Kastan, M.B. reported that p53 protein accumulates in cells exposed to ionizing radiation. The accumulation of p53 protein is in response to DNA damage, most importantly double-strand breaks, that results from exposure to ionizing radiation. The rise in cellular p53 levels is necessary for an arrest in the G{sub 1} phase of the cell cycle to provide additional time for DNA repair. The p53 response has also been demonstrated to enhance PCNA-dependent repair. p53 is thus an important regulator of the cellular response to DNA-damaging radiation. From this data, it can be concluded that the magnitude of the p53 response is not dependent on the phase of culture growth.

  10. Quasar redshifts: the intrinsic component

    NASA Astrophysics Data System (ADS)

    Hansen, Peter M.

    2016-09-01

    The large observed redshift of quasars has suggested large cosmological distances and a corresponding enormous energy output to explain the brightness or luminosity as seen at earth. Alternative or complementary sources of redshift have not been identified by the astronomical community. This study examines one possible source of additional redshift: an intrinsic component based on the plasma characteristics of high temperature and high electron density which are believed to be present.

  11. Fanconi anemia proteins FANCD2 and FANCI exhibit different DNA damage responses during S-phase

    PubMed Central

    Sareen, Archana; Chaudhury, Indrajit; Adams, Nicole; Sobeck, Alexandra

    2012-01-01

    Fanconi anemia (FA) pathway members, FANCD2 and FANCI, contribute to the repair of replication-stalling DNA lesions. FA pathway activation relies on phosphorylation of FANCI by the ataxia telangiectasia and Rad3-related (ATR) kinase, followed by monoubiquitination of FANCD2 and FANCI by the FA core complex. FANCD2 and FANCI are thought to form a functional heterodimer during DNA repair, but it is unclear how dimer formation is regulated or what the functions of the FANCD2–FANCI complex versus the monomeric proteins are. We show that the FANCD2–FANCI complex forms independently of ATR and FA core complex, and represents the inactive form of both proteins. DNA damage-induced FA pathway activation triggers dissociation of FANCD2 from FANCI. Dissociation coincides with FANCD2 monoubiquitination, which significantly precedes monoubiquitination of FANCI; moreover, monoubiquitination responses of FANCD2 and FANCI exhibit distinct DNA substrate specificities. A phosphodead FANCI mutant fails to dissociate from FANCD2, whereas phosphomimetic FANCI cannot interact with FANCD2, indicating that FANCI phosphorylation is the molecular trigger for FANCD2–FANCI dissociation. Following dissociation, FANCD2 binds replicating chromatin prior to—and independently of—FANCI. Moreover, the concentration of chromatin-bound FANCD2 exceeds that of FANCI throughout replication. Our results suggest that FANCD2 and FANCI function separately at consecutive steps during DNA repair in S-phase. PMID:22753026

  12. Experimental infection with Toxocara cati in pigs: migratory pattern and pathological response in early phase.

    PubMed

    Sommerfelt, Irma Estela; Duchene, Adriana; Daprato, Betina; Lopez, Clara María; Cardillo, Natalia; Franco, Aníbal Juan

    2014-01-01

    Experimental inoculations of approximately 100,000 infective Toxocara cati larval eggs were done in twelve pigs. The T. cati eggs used for inoculation were collected from cat's feces. Another group of three pigs served as an uninfected control. Groups of infected pigs were euthanized at seven, 14, 21, and 28 days post-inoculation (dpi). Tissue samples were taken for digestion and histopathology changes in early phase. The number of larvae recovered from the lungs peaked at seven and 14 dpi and were also present at 21, and 28 dpi. Larvae of T. cati were present in the lymph nodes of the small and large intestine at seven, 14, and 28 dpi and at seven, 14, 21, and 28 dpi respectively. In other studied tissues, no larvae or less than one larva per gram was detected. The pathological response observed in the liver and lungs at seven and 14 dpi, showed white spots on the liver surface and areas of consolidation were observed in the lungs. The lungs showed an inflammatory reaction with larvae in center at 28 dpi. In the liver we observed periportal and perilobular hepatitis. The lymph nodes of the intestines displayed eosinophil lymphadenitis with reactive centers containing parasitic forms in some of them. The granulomatous reaction was not observed in any tissues. The role of the other examined tissues had less significance. The relevance of this parasite as an etiological agent that leads to disease in paratenic hosts is evident.

  13. Decoherence: Intrinsic, Extrinsic, and Environmental

    NASA Astrophysics Data System (ADS)

    Stamp, Philip

    2012-02-01

    Environmental decoherence times have been difficult to predict in solid-state systems. In spin systems, environmental decoherence is predicted to arise from nuclear spins, spin-phonon interactions, and long-range dipolar interactions [1]. Recent experiments have confirmed these predictions quantitatively in crystals of Fe8 molecules [2]. Coherent spin dynamics was observed over macroscopic volumes, with a decoherence Q-factor Qφ= 1.5 x10^6 (the upper predicted limit in this system being Qφ= 6 x10^7). Decoherence from dipolar interactions is particularly complex, and depends on the shape and the quantum state of the system. No extrinsic ``noise'' decoherence was observed. The generalization to quantum dot and superconducting qubit systems is also discussed. We then discuss searches for ``intrinsic'' decoherence [3,4], coming from non-linear corrections to quantum mechanics. Particular attention is paid to condensed matter tests of such intrinsic decoherence, in hybrid spin/optomechanical systems, and to ways of distinguishing intrinsic decoherence from environmental and extrinsic decoherence sources. [4pt] [1] Morello, A. Stamp, P. C. E. & Tupitsyn, Phys. Rev. Lett. 97, 207206 (2006).[0pt] [2] S. Takahashi et al., Nature 476, 76 (2011).[0pt] [3] Stamp, P. C. E., Stud. Hist. Phil. Mod. Phys. 37, 467 (2006). [0pt] [4] Stamp, P.C.E., Phil. Trans. Roy. Soc. A (to be published)

  14. Troponins, intrinsic disorder, and cardiomyopathy.

    PubMed

    Na, Insung; Kong, Min J; Straight, Shelby; Pinto, Jose R; Uversky, Vladimir N

    2016-08-01

    Cardiac troponin is a dynamic complex of troponin C, troponin I, and troponin T (TnC, TnI, and TnT, respectively) found in the myocyte thin filament where it plays an essential role in cardiac muscle contraction. Mutations in troponin subunits are found in inherited cardiomyopathies, such as hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM). The highly dynamic nature of human cardiac troponin and presence of numerous flexible linkers in its subunits suggest that understanding of structural and functional properties of this important complex can benefit from the consideration of the protein intrinsic disorder phenomenon. We show here that mutations causing decrease in the disorder score in TnI and TnT are significantly more abundant in HCM and DCM than mutations leading to the increase in the disorder score. Identification and annotation of intrinsically disordered regions in each of the troponin subunits conducted in this study can help in better understanding of the roles of intrinsic disorder in regulation of interactomes and posttranslational modifications of these proteins. These observations suggest that disease-causing mutations leading to a decrease in the local flexibility of troponins can trigger a whole plethora of functional changes in the heart. PMID:27074551

  15. Restricted feeding entrains rhythms of inflammation-related factors without promoting an acute-phase response.

    PubMed

    Luna-Moreno, Dalia; Aguilar-Roblero, Raúl; Díaz-Muñoz, Mauricio

    2009-10-01

    A restricted schedule of food access promotes numerous metabolic and physiological adaptations to optimize the biochemical handling of nutrients. The restricted feeding activates responses in hypothalamic and midbrain areas, as well as in peripheral organs involved in energy metabolism. A restricted feeding schedule (RFS) is associated with marked behavioral arousal coincident with the food anticipatory activity (FAA) and extreme hyperphagia during food access. Food restriction is also accompanied by changes in an array of stress-related parameters, such as increase in corticosterone, slower rate in body weight gain, and reduction in retroperitoneal and epididymal adipose tissue. During RFS, the liver shows a diversity of biochemical and physiologically adaptations that are advantageous for food ingestion and processing, as well as for adequate nutrient distribution to other tissues. Taking into account the probable relationship between stressful conditions and the metabolic adaptations in the liver, we addressed whether an acute-phase response (APR), or a pro-inflammatory state, occurred after three weeks of 2 h food restriction. First, we compared the circulating levels of inflammation markers (interleukin-1alpha, interleukin-6, tumor necrosis factor-alpha), and APR proteins (C-reactive protein and fibrinogen) in rats under food restriction to those in rats treated with lipopolysacharide, a strong inducer of the APR. Second, the influence of RFS on the daily rhythms of systemic cytokines and APR proteins was characterized. Third, we tested if the feeding condition (22 h fasting and 2 h refeeding) influences these parameters. Finally, we assessed if a local stressed state was established in the liver associated with the restricted feeding by measuring the activation of the transcriptional factor NF-kappaB (nuclear factor kappa-light-chain-enhancer of activated B cells). The results showed that the following occurred during RFS: no APR was implemented; food

  16. Phase-Sensitive Midbrain Neurons in Eigenmannia: Neural Correlates of the Jamming Avoidance Response

    NASA Astrophysics Data System (ADS)

    Bastian, Joseph; Heiligenberg, Walter

    1980-08-01

    Neurons in the torus semicircularis of the weakly electric fish Eigenmannia encode phase differences between sinusoidal electrical stimuli received in different body regions. These fish normally experience time-varying phase differences when the electric organ discharge fields of two or more individuals overlap. These phase differences supply information necessary for the animal's jamming avoidance behavior.

  17. Intrinsic modulation of pulse-coupled integrate-and-fire neurons

    NASA Astrophysics Data System (ADS)

    Coombes, S.; Lord, G. J.

    1997-11-01

    Intrinsic neuromodulation is observed in sensory and neuromuscular circuits and in biological central pattern generators. We model a simple neuronal circuit with a system of two pulse-coupled integrate-and-fire neurons and explore the parameter regimes for periodic firing behavior. The inclusion of biologically realistic features shows that the speed and onset of neuronal response plays a crucial role in determining the firing phase for periodic rhythms. We explore the neurophysiological function of distributed delays arising from both the synaptic transmission process and dendritic structure as well as discrete delays associated with axonal communication delays. Bifurcation and stability diagrams are constructed with a mixture of simple analysis, numerical continuation and the Kuramoto phase-reduction technique. Moreover, we show that, for asynchronous behavior, the strength of electrical synapses can control the firing rate of the system.

  18. MICROBIAL RESPONSES TO IN SITU CHEMICAL OXIDATION, SIX-PHASE HEATING, AND STEAM INJECTION REMEDIATION TECHNOLOGIES IN GROUND WATER

    EPA Science Inventory

    The evaluation of microbial responses to three in situ source removal remedial technologies including permanganate-based in-situ chemical oxidation (ISCO), six-phase heating (SPH), and steam injection (SI) was performed at Cape Canaveral Air Station in Florida. The investigatio...

  19. The acute phase inflammatory response to maximal exercise testing in children and young adults with sickle cell anaemia.

    PubMed

    Liem, Robert I; Onyejekwe, Kasiemobi; Olszewski, Marie; Nchekwube, Chisalu; Zaldivar, Frank P; Radom-Aizik, Shlomit; Rodeghier, Mark J; Thompson, Alexis A

    2015-12-01

    Although individuals with sickle cell anaemia (SCA) have elevated baseline inflammation and endothelial activation, the acute phase response to maximal exercise has not been evaluated among children with SCA. We measured the acute phase response to maximal exercise testing for soluble vascular cell adhesion molecule (sVCAM) as well as interleukin 6 (IL6), total white blood cell (WBC) count, C-reactive protein (CRP) and D-dimer in a cohort of children with SCA and matched controls at baseline, immediately after, and 30, 60 and 120 min following exercise. Despite higher baseline levels of all biomarkers except CRP, the acute phase response from baseline to immediately after exercise was significantly greater in subjects versus controls for CRP (2·1 vs. 0·2 mg/l, P = 0·02) and D-dimer (160 vs. 10 μg/l, P < 0·01) only. Similar between-group trends were observed over time for all biomarkers, including sVCAM, IL6, total WBC, CRP and D-dimer. Lower fitness, defined by peak oxygen consumption (VO2 ), was independently associated with greater acute phase responses to exercise for sVCAM. Our results suggest maximal exercise may not be associated with any greater escalation of endothelial activation or inflammation in SCA and provide preliminary biomarker evidence for the safety of brief, high-intensity physical exertion in children with SCA.

  20. Dried citrus pulp modulates the physiological and acute phase responses of crossbred heifers to an endotoxin challenge

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study examined the effect of feeding dried citrus pulp (CP) pellets on the physiological and acute phase responses (APR) of newly-received crossbred heifers to an endotoxin (lipopolysaccharide; LPS) challenge. Heifers (n=24; 218.3±2.4 kg) were obtained from commercial sale barns and transported...

  1. Yeast cell wall supplementation alters the physiological and acute phase responses of crossbred heifers to an endotoxin challenge

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A study was conducted to determine the effect of feeding yeast cell wall (YCW) products on the physiological and acute phase responses of crossbred newly-received heifers to an endotoxin challenge. Heifers (n = 24; 219 ± 2.4 kg) were separated into treatment groups receiving a Control diet (n = 8), ...

  2. Supplementation of Lactobacillus acidophilus fermentation product can attenuate the acute phase response following a lipopolysaccharide challenge in pigs.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study was designed to determine if feeding a Lactobacillus acidophilus fermentation product to weaned pigs would reduce stress and acute phase responses (APR) following a lipopolysaccharide (LPS) challenge. Pigs (n=30; 6.4±0.1 kilograms body weight) were housed individually in pens with ad libi...

  3. Enhancement of the acute phase response to lipopolysaccharide in feedlot steers supplemented with OmniGen-AF

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study was designed to determine the effect of supplementing feedlot steers with OmniGen-AF on the acute phase response to a lipopolysaccharide (LPS) challenge. Steers (n = 18; 270 ± 5 kilograms body weight) were separated into two treatment groups (n=9/treatment): one group was fed a standard ...

  4. OmniGen-AF supplementation modulated the physiological and acute phase responses of Brahman heifers to an endotoxin challenge

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study examined the effect of feeding OmniGen-AF (OG; Prince Agri Products) on the physiological and acute phase responses (APR) of newly-weaned heifers to an endotoxin (lipopolysaccharide; LPS) challenge. Brahman heifers (n=24; 183±5 kilograms) from the Texas AgriLife Research Center in Overton...

  5. The effect of feeding endophyte-infected fescue on the acute phase response to lipopolysaccharide in beef heifers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Angus heifers (n = 22; 292 ± 9.0 kg body weight) were paired by body weight and randomly placed on either an endophyte-infected (E+) or endophyte-free (E-) diet for 10 days to determine the influence of feeding endophyte-infected fescue on the physiological and acute phase responses of beef heifers ...

  6. Prenatal transportation alters the acute phase response (APR) of bull calves exposed to a lipopolysaccharide (LPS) challenge

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study was designed to determine if prenatal transportation influences the acute phase response (APR) to a postnatal Lipopolysaccharide (LPS) challenge. Pregnant Brahman cows (n=96) matched by age and parity were separated into transported (TRANS; n=48; transported for 2 hours on gestational day...

  7. Phase I to II cross-induction of xenobiotic metabolizing enzymes: A feedforward control mechanism for potential hormetic responses

    SciTech Connect

    Zhang Qiang Pi Jingbo; Woods, Courtney G.; Andersen, Melvin E.

    2009-06-15

    Hormetic responses to xenobiotic exposure likely occur as a result of overcompensation by the homeostatic control systems operating in biological organisms. However, the mechanisms underlying overcompensation that leads to hormesis are still unclear. A well-known homeostatic circuit in the cell is the gene induction network comprising phase I, II and III metabolizing enzymes, which are responsible for xenobiotic detoxification, and in many cases, bioactivation. By formulating a differential equation-based computational model, we investigated in this study whether hormesis can arise from the operation of this gene/enzyme network. The model consists of two feedback and one feedforward controls. With the phase I negative feedback control, xenobiotic X activates nuclear receptors to induce cytochrome P450 enzyme, which bioactivates X into a reactive metabolite X'. With the phase II negative feedback control, X' activates transcription factor Nrf2 to induce phase II enzymes such as glutathione S-transferase and glutamate cysteine ligase, etc., which participate in a set of reactions that lead to the metabolism of X' into a less toxic conjugate X''. The feedforward control involves phase I to II cross-induction, in which the parent chemical X can also induce phase II enzymes directly through the nuclear receptor and indirectly through transcriptionally upregulating Nrf2. As a result of the active feedforward control, a steady-state hormetic relationship readily arises between the concentrations of the reactive metabolite X' and the extracellular parent chemical X to which the cell is exposed. The shape of dose-response evolves over time from initially monotonically increasing to J-shaped at the final steady state-a temporal sequence consistent with adaptation-mediated hormesis. The magnitude of the hormetic response is enhanced by increases in the feedforward gain, but attenuated by increases in the bioactivation or phase II feedback loop gains. Our study suggests a

  8. Intrinsic spin torque without spin-orbit coupling

    PubMed Central

    Kim, Kyoung-Whan; Lee, Kyung-Jin; Lee, Hyun-Woo; Stiles, M. D.

    2016-01-01

    We derive an intrinsic contribution to the non-adiabatic spin torque for non-uniform magnetic textures. It differs from previously considered contributions in several ways and can be the dominant contribution in some models. It does not depend on the change in occupation of the electron states due to the current flow but rather is due to the perturbation of the electronic states when an electric field is applied. Therefore it should be viewed as electric-field-induced rather than current-induced. Unlike previously reported non-adiabatic spin torques, it does not originate from extrinsic relaxation mechanisms nor spin-orbit coupling. This intrinsic non-adiabatic spin torque is related by a chiral connection to the intrinsic spin-orbit torque that has been calculated from the Berry phase for Rashba systems. PMID:26877628

  9. Response of some pi-phase-shifted Bragg gratings to elevated pressure

    NASA Astrophysics Data System (ADS)

    Bal, Harpreet K.; Dragomir, Nicoleta M.; Sidiroglou, Fotios; Wade, Scott A.; Baxter, Greg W.; Collins, Stephen F.

    2011-05-01

    The effect of pressures up to 200 kPa on pi-phase-shifted Bragg gratings was investigated in several types of fibers placed in a pressure chamber. Standard and alternative types of pi-phase shifted gratings were studied, and changes in reflection spectra caused by pressure changes were monitored. The alternative pi-phase shifted grating was fabricated using a phase mask with 536-nm pitch exhibiting features at twice the Bragg wavelength near 1552 nm due to the interleaved refractive index modulations along the fiber core with the periodicity of the phase mask. The three gratings studied exhibited quite different variation in Bragg wavelength with increased pressure for the different fiber types, and the alternative pi-phase-shifted grating in Corning HI 1060 FLEX fiber also suffered a significant change in the shape of the peaks.

  10. Looking the World from Inside:. Intrinsic Geometry of Complex Systems

    NASA Astrophysics Data System (ADS)

    Boi, L.

    2012-12-01

    In this paper we shall address some meeting points between geometry and biology, in order to show that geometrical things and transformations take part intrinsically in the living systems. We focus on some features of macromolecular structures like DNA-proteins complexes. All things we speak about take place in the 3-dimensional space of a living cell and particularly in its nucleus, which of course interacts in many ways and at different levels with the whole cell, its cytoplasm and the organelles. Ideally, we think we should rather consider, instead of a 3-dimensional space, a configuration space characterized by all its phase spaces, since a living being is a very complex dynamical system, but this would be a too difficult, impossible task. This is of course a very partial view, an oversimplification, of what really happen in our organisms. Nevertheless, We believe that in biology we are today facing the following problem: how small or local changes in a living system do affect the global behaviour and response of the whole organisms? We search for an answer by arguing that mostly overall features of living systems are emergent properties of organization and regulation defined at the macroscopic level of their morphology and physiological behaviours, and also by showing that in complex living systems self-organization ensures robustness without loss of plasticity, in the sense that perturbations in the interactions properties of its single parts generally do not have damaging consequences on the living form as a whole.

  11. Intrinsic motivation and amotivation in first episode and prolonged psychosis.

    PubMed

    Luther, Lauren; Lysaker, Paul H; Firmin, Ruth L; Breier, Alan; Vohs, Jenifer L

    2015-12-01

    The deleterious functional implications of motivation deficits in psychosis have generated interest in examining dimensions of the construct. However, there remains a paucity of data regarding whether dimensions of motivation differ over the course of psychosis. Therefore, this study examined two motivation dimensions, trait-like intrinsic motivation, and the negative symptom of amotivation, and tested the impact of illness phase on the 1) levels of these dimensions and 2) relationship between these dimensions. Participants with first episode psychosis (FEP; n=40) and prolonged psychosis (n=66) completed clinician-rated measures of intrinsic motivation and amotivation. Analyses revealed that when controlling for group differences in gender and education, the FEP group had significantly more intrinsic motivation and lower amotivation than the prolonged psychosis group. Moreover, intrinsic motivation was negatively correlated with amotivation in both FEP and prolonged psychosis, but the magnitude of the relationship did not statistically differ between groups. These findings suggest that motivation deficits are more severe later in the course of psychosis and that low intrinsic motivation may be partially independent of amotivation in both first episode and prolonged psychosis. Clinically, these results highlight the importance of targeting motivation in early intervention services.

  12. Intrinsic Cellular Properties and Connectivity Density Determine Variable Clustering Patterns in Randomly Connected Inhibitory Neural Networks

    PubMed Central

    Rich, Scott; Booth, Victoria; Zochowski, Michal

    2016-01-01

    The plethora of inhibitory interneurons in the hippocampus and cortex play a pivotal role in generating rhythmic activity by clustering and synchronizing cell firing. Results of our simulations demonstrate that both the intrinsic cellular properties of neurons and the degree of network connectivity affect the characteristics of clustered dynamics exhibited in randomly connected, heterogeneous inhibitory networks. We quantify intrinsic cellular properties by the neuron's current-frequency relation (IF curve) and Phase Response Curve (PRC), a measure of how perturbations given at various phases of a neurons firing cycle affect subsequent spike timing. We analyze network bursting properties of networks of neurons with Type I or Type II properties in both excitability and PRC profile; Type I PRCs strictly show phase advances and IF curves that exhibit frequencies arbitrarily close to zero at firing threshold while Type II PRCs display both phase advances and delays and IF curves that have a non-zero frequency at threshold. Type II neurons whose properties arise with or without an M-type adaptation current are considered. We analyze network dynamics under different levels of cellular heterogeneity and as intrinsic cellular firing frequency and the time scale of decay of synaptic inhibition are varied. Many of the dynamics exhibited by these networks diverge from the predictions of the interneuron network gamma (ING) mechanism, as well as from results in all-to-all connected networks. Our results show that randomly connected networks of Type I neurons synchronize into a single cluster of active neurons while networks of Type II neurons organize into two mutually exclusive clusters segregated by the cells' intrinsic firing frequencies. Networks of Type II neurons containing the adaptation current behave similarly to networks of either Type I or Type II neurons depending on network parameters; however, the adaptation current creates differences in the cluster dynamics

  13. Does the human odometer use an extrinsic or intrinsic metric?

    PubMed

    Chrastil, Elizabeth R; Warren, William H

    2014-01-01

    It is commonly assumed that path integration is based on an extrinsic measure of the objective distance traversed during locomotion. In contrast, biological odometers may rely on embodied intrinsic measures, such as idiothetic information specific to an action mode. We investigated this question using a distance reproduction task in which participants traveled an outbound distance and then reproduced that distance using the same or a different action mode. The extrinsic model predicted that distance reproduction should be invariant across action modes, whereas the intrinsic model predicted invariance only within an action mode. In Experiment 1, we held the outbound mode constant while varying the response mode (walk-walk, walk-throw) and corrected for response production error (view-walk, view-throw). In Experiment 2, we crossed different gaits in the outbound and response modes (walk, gallop). In both cases, we found that distance reproduction was significantly more accurate when the outbound and response modes matched, consistent with the intrinsic model. The results indicate that the human odometer preferentially relies on an intrinsic, rather than an extrinsic, metric. This solution is sufficient to support successful path integration within an action mode (but not across action modes), without the difficulties of objective distance estimation. PMID:24197502

  14. Gas-phase chemistry of diphosphate anions as a tool to investigate the intrinsic requirements of phosphate ester enzymatic reactions: the [M1M2HP2O7]- ions.

    PubMed

    Pepi, Federico; Barone, Vincenzo; Cimino, Paola; Ricci, Andreina

    2007-01-01

    Experimental studies on gaseous inorganic phosphate ions are practically nonexistent, yet they can prove helpful for a better understanding of the mechanisms of phosphate ester enzymatic processes. The present contribution extends our previous investigations on the gas-phase ion chemistry of diphosphate species to the [M(1)M(2)HP(2)O(7)](-) ions where M(1) and M(2) are the same or different and correspond to the Li, Na, K, Cs, and Rb cations. The diphosphate ions are formed by electrospray ionization of 10(-4) M solutions of Na(5)P(3)O(10) in CH(3)CN/H(2)O (1/1) and MOH bases or M salts as a source of M(+) cations. The joint application of mass spectrometric techniques and quantum-mechanical calculations makes it possible to characterize the gaseous [M(1)M(2)HP(2)O(7)](-) ions as a mixed ionic population formed by two isomeric species: linear diphosphate anion coordinated to two M(+) cations (group I) and [PO(3)M(1)M(2)HPO(4)](-) clusters (group II). The relative gas-phase stabilities and activation barriers for the isomerization I-->II, which depend on the nature of the M(+) cations, highlight the electronic susceptibility of P-O-P bond breaking in the active site of enzymes. The previously unexplored gas-phase reactivity of [M(1)M(2)HP(2)O(7)](-) ions towards alcohols of different acidity was investigated by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR/MS). The reaction proceeds by addition of the alcohol molecule followed by elimination of a water molecule.

  15. Nuclear Filtering of Intrinsic Charm

    SciTech Connect

    Kopeliovich, B. Z.; Potashnikova, I. K.; Schmidt, Ivan

    2010-11-12

    Nuclei are transparent for a heavy intrinsic charm (IC) component of the beam hadrons, what leads to an enhanced nuclear dependence of open charm production at large Feynman x{sub F}. Indeed, such an effect is supported by data from the SELEX experiment published recently [1]. Our calculations reproduce well the data, providing strong support for the presence of IC in hadrons in amount less than 1%. Moreover, we performed an analysis of nuclear effects in J/{Psi} production and found at large x{sub F} a similar, albeit weaker effect, which does not contradict data.

  16. Lack of association of acute phase response proteins with hormone levels and antidepressant medication in perimenopausal depression

    PubMed Central

    2014-01-01

    Background Major depression is associated with higher plasma levels of positive acute-phase proteins, as well as with lower plasma levels of negative acute-phase proteins. The aim of this study is to examine the levels of acute-phase response proteins and whether these levels are influenced by reproductive hormones and antidepressant medication in the perimenopausal depression. Methods Sixty-five women (age range: 40–58 years old) participated in this study. All women were in the perimenopausal phase. The diagnosis of depression was made through a psychiatric interview and with the aid of Hamilton Depression Rating Scale 17 (HAM-D 17). The acute-phase response proteins, such as haptoglobin (HP), transferrine (TRf), α1-antitrypsin, complement protein 3 (C3), complement protein 4 (C4) and C-reactive protein (CRP) and the reproductive hormones, for example follicle-stimulating hormone (FSH), luteinizing hormone (LH) and estradiol (E2), were analyzed using standard laboratory methods. Pearson’s correlations were applied to evaluate the relationship between acute-phase proteins and hormones. Results Perimenopausal women were divided into three groups. The first group consisted of normal controls, the second one involved depressed perimenopausal women, who were taking selective serotonin reuptake inhibitors (SSRIs), and the third one included depressed women that were not treated with SSRIs. Depressed women in perimenopause, when being compared to non-depressed women, did not differ as to serum levels of acute-phase proteins. There was a positive correlation between HP and E2 in depressed perimenopausal women, who were not taking SSRIs. Conclusions The lack of association between acute-phase proteins and depressive mood mentioned in this study does not support previous findings in patients with major depression. This negative finding in perimenopausal depression indicates either the absence or a more complex nature of the interactions between acute-phase proteins

  17. Effect Anticipation Affects Perceptual, Cognitive, and Motor Phases of Response Preparation: Evidence from an Event-Related Potential (ERP) Study

    PubMed Central

    Harrison, Neil R.; Ziessler, Michael

    2016-01-01

    The anticipation of action effects is a basic process that can be observed even for key-pressing responses in a stimulus-response paradigm. In Ziessler et al.’s (2012) experiments participants first learned arbitrary effects of key-pressing responses. In the test phase an imperative stimulus determined the response, but participants withheld the response until a Go-stimulus appeared. Reaction times (RTs) were shorter if the Go-stimulus was compatible with the learned response effect. This is strong evidence that effect representations were activated during response planning. Here, we repeated the experiment using event-related potentials (ERPs), and we found that Go-stimulus locked ERPs depended on the compatibility relationship between the Go-stimulus and the response effect. In general, this supports the interpretation of the behavioral data. More specifically, differences in the ERPs between compatible and incompatible Go-stimuli were found for the early perceptual P1 component and the later frontal P2 component. P1 differences were found only in the second half of the experiment and for long stimulus onset asynchronies (SOAs) between imperative stimulus and Go-stimulus, i.e., when the effect was fully anticipated and the perceptual system was prepared for the effect-compatible Go-stimulus. P2 amplitudes, likely associated with evaluation and conflict detection, were larger when Go-stimulus and effect were incompatible; presumably, incompatibility increased the difficulty of effect anticipation. Onset of response-locked lateralized readiness potentials (R-LRPs) occurred earlier under incompatible conditions indicating extended motor processing. Together, these results strongly suggest that effect anticipation affects all (i.e., perceptual, cognitive, and motor) phases of response preparation. PMID:26858621

  18. Effect Anticipation Affects Perceptual, Cognitive, and Motor Phases of Response Preparation: Evidence from an Event-Related Potential (ERP) Study.

    PubMed

    Harrison, Neil R; Ziessler, Michael

    2016-01-01

    The anticipation of action effects is a basic process that can be observed even for key-pressing responses in a stimulus-response paradigm. In Ziessler et al.'s (2012) experiments participants first learned arbitrary effects of key-pressing responses. In the test phase an imperative stimulus determined the response, but participants withheld the response until a Go-stimulus appeared. Reaction times (RTs) were shorter if the Go-stimulus was compatible with the learned response effect. This is strong evidence that effect representations were activated during response planning. Here, we repeated the experiment using event-related potentials (ERPs), and we found that Go-stimulus locked ERPs depended on the compatibility relationship between the Go-stimulus and the response effect. In general, this supports the interpretation of the behavioral data. More specifically, differences in the ERPs between compatible and incompatible Go-stimuli were found for the early perceptual P1 component and the later frontal P2 component. P1 differences were found only in the second half of the experiment and for long stimulus onset asynchronies (SOAs) between imperative stimulus and Go-stimulus, i.e., when the effect was fully anticipated and the perceptual system was prepared for the effect-compatible Go-stimulus. P2 amplitudes, likely associated with evaluation and conflict detection, were larger when Go-stimulus and effect were incompatible; presumably, incompatibility increased the difficulty of effect anticipation. Onset of response-locked lateralized readiness potentials (R-LRPs) occurred earlier under incompatible conditions indicating extended motor processing. Together, these results strongly suggest that effect anticipation affects all (i.e., perceptual, cognitive, and motor) phases of response preparation.

  19. Understanding Plant Community Responses to Combinations of Biotic and Abiotic Factors in Different Phases of the Plant Growth Cycle

    PubMed Central

    Wood, Kevin A.; Stillman, Richard A.; Clarke, Ralph T.; Daunt, Francis; O’Hare, Matthew T.

    2012-01-01

    Understanding plant community responses to combinations of biotic and abiotic factors is critical for predicting ecosystem response to environmental change. However, studies of plant community regulation have seldom considered how responses to such factors vary with the different phases of the plant growth cycle. To address this deficit we studied an aquatic plant community in an ecosystem subject to gradients in mute swan (Cygnus olor) herbivory, riparian shading, water temperature and distance downstream of the river source. We quantified abundance, species richness, evenness, flowering and dominance in relation to biotic and abiotic factors during the growth-, peak-, and recession-phases of the plant growth cycle. We show that the relative importance of biotic and abiotic factors varied between plant community properties and between different phases of the plant growth cycle. Herbivory became more important during the later phases of peak abundance and recession due to an influx of swans from adjacent pasture fields. Shading by riparian vegetation also had a greater depressing effect on biomass in later seasons, probably due to increased leaf abundance reducing light intensity reaching the aquatic plants. The effect of temperature on community diversity varied between upstream and downstream sites by altering the relative competitiveness of species at these sites. These results highlight the importance of seasonal patterns in the regulation of plant community structure and function by multiple factors. PMID:23166777

  20. Stimuli-sensitive intrinsically disordered protein brushes

    NASA Astrophysics Data System (ADS)

    Srinivasan, Nithya; Bhagawati, Maniraj; Ananthanarayanan, Badriprasad; Kumar, Sanjay

    2014-10-01

    Grafting polymers onto surfaces at high density to yield polymer brush coatings is a widely employed strategy to reduce biofouling and interfacial friction. These brushes almost universally feature synthetic polymers, which are often heterogeneous and do not readily allow incorporation of chemical functionalities at precise sites along the constituent chains. To complement these synthetic systems, we introduce a biomimetic, recombinant intrinsically disordered protein that can assemble into an environment-sensitive brush. This macromolecule adopts an extended conformation and can be grafted to solid supports to form oriented protein brushes that swell and collapse dramatically with changes in solution pH and ionic strength. We illustrate the value of sequence specificity by using proteases with mutually orthogonal recognition sites to modulate brush height in situ to predictable values. This study demonstrates that stimuli-responsive brushes can be fabricated from proteins and introduces them as a new class of smart biomaterial building blocks.

  1. Lack of acute phase response in the livers of mice exposed to diesel exhaust particles or carbon black by inhalation

    PubMed Central

    Saber, Anne T; Halappanavar, Sabina; Folkmann, Janne K; Bornholdt, Jette; Boisen, Anne Mette Z; Møller, Peter; Williams, Andrew; Yauk, Carole; Vogel, Ulla; Loft, Steffen; Wallin, Håkan

    2009-01-01

    Background Epidemiologic and animal studies have shown that particulate air pollution is associated with increased risk of lung and cardiovascular diseases. Although the exact mechanisms by which particles induce cardiovascular diseases are not known, studies suggest involvement of systemic acute phase responses, including C-reactive protein (CRP) and serum amyloid A (SAA) in humans. In this study we test the hypothesis that diesel exhaust particles (DEP) – or carbon black (CB)-induced lung inflammation initiates an acute phase response in the liver. Results Mice were exposed to filtered air, 20 mg/m3 DEP or CB by inhalation for 90 minutes/day for four consecutive days; we have previously shown that these mice exhibit pulmonary inflammation (Saber AT, Bornholdt J, Dybdahl M, Sharma AK, Loft S, Vogel U, Wallin H. Tumor necrosis factor is not required for particle-induced genotoxicity and pulmonary inflammation., Arch. Toxicol. 79 (2005) 177–182). As a positive control for the induction of an acute phase response, mice were exposed to 12.5 mg/kg of lipopolysaccharide (LPS) intraperitoneally. Quantitative real time RT-PCR was used to examine the hepatic mRNA expression of acute phase proteins, serum amyloid P (Sap) (the murine homologue of Crp) and Saa1 and Saa3. While significant increases in the hepatic expression of Sap, Saa1 and Saa3 were observed in response to LPS, their levels did not change in response to DEP or CB. In a comprehensive search for markers of an acute phase response, we analyzed liver tissue from these mice using high density DNA microarrays. Globally, 28 genes were found to be significantly differentially expressed in response to DEP or CB. The mRNA expression of three of the genes (serine (or cysteine) proteinase inhibitor, clade A, member 3C, apolipoprotein E and transmembrane emp24 domain containing 3) responded to both exposures. However, these changes were very subtle and were not confirmed by real time RT-PCR. Conclusion Our findings

  2. Is The Intrinsic Spin Hall Effect Measurable?

    NASA Astrophysics Data System (ADS)

    Yang, Zhaoyang

    2005-03-01

    Despite of the large intrinsic spin Hall conductivity in a spin- orbit coupled material predicted theoretically, we show that the intrinsic spin Hall effect in any diffusive sample is not measurable via conventional transport methods, thus the research on the intrinsic spin Hall effect is limited at the pure theoretical content. After generally defining the intrinsic and extrinsic transport coefficients, we show that the intrinsic magnetization Hall current, which is the sum of the intrinsic spin and intrinsic orbit-angular-momentum Hall currents, is identically zero. More importantly, we demonstrate that the equation of motion for the spin density does not depend on the intrinsic spin Hall current, therefore the transverse spin accumulation is solely determined by the extrinsic spin Hall current. The zero intrinsic magnetization Hall current and the independence of the spin accumulation on the intrinsic spin Hall effect lead us to conclude that the intrinsic spin Hall effect can not be assessed by conventional spin transport experiments based on the measurement of the magnetization current and the spin accumulation at the edge of the sample.

  3. Metabolizable protein supply modulated the acute-phase response following vaccination of beef steers.

    PubMed

    Moriel, P; Arthington, J D

    2013-12-01

    Our objective was to evaluate the effects of MP supply, through RUP supplementation, on the acute-phase response of beef steers following vaccination. On d 0, Brangus-crossbred steers (n = 24; 173 ± 31 kg; 175 ± 16 d of age) were randomly assigned to receive 1 of 3 isocaloric diets formulated to provide 85, 100, and 115% of the daily MP requirements of a beef steer gaining 0.66 kg of BW daily. Diets were limit-fed at 1.8% of BW (DM basis) and individually provided to steers once daily (0800 h) from d 0 to 29. Steers were weighed on d 0 and 29, following a 12-h period of feed and water withdrawal. On d 7, steers were vaccinated against Mannheimia haemolytica (OneShot, Pfizer), and blood samples were collected on d 0, 7, 8, 10, 14, 21, and 30. Plasma metabolites were analyzed as repeated measures using the MIXED procedure of SAS. Final BW and ADG were similar (P ≥ 0.50) among treatments (mean = 184 ± 9 kg and 0.5 ± 0.08 kg/d, respectively). Effects of time were detected (P < 0.01) for plasma concentrations of all acute-phase proteins, which peaked between d 7 to 14, returning to baseline concentrations by d 29. Treatment effects were not detected (P ≥ 0.19) for plasma concentrations of acid-soluble protein, albumin, fibrinogen, IGF-1 and serum amyloid-A. Plasma concentrations of total protein (TP) and plasma urea nitrogen (PUN) increased (P ≤ 0.05) with increasing supply of MP (87.1, 89.6, and 90.1 ± 1.09 mg TP/mL and 6.1, 8.3, and 10.3 ± 0.41 mg PUN/dL for 85, 100, and 115% MP steers, respectively). From d 10 to 29, steers provided 115% MP had less (P < 0.001) plasma concentrations of ceruloplasmin than steers fed 85 and 100% MP, which had similar plasma ceruloplasmin concentrations. On d 14, plasma concentrations of haptoglobin were greatest (P ≤ 0.06) for steers fed 115% MP, intermediate for 100% MP, and least for 85% MP (0.98, 0.71 and 0.44 ± 0.099 mg/mL, respectively). On d 10, plasma concentrations of creatinine were greater (P = 0.01) for steers

  4. Seismic Safety Margins Research Program. Phase I, Final report: subsystem response (Project V). Volume 6

    SciTech Connect

    Shieh, L. C.; Chuang, T. Y.; O'Connell, W. J.

    1981-07-01

    This document reports on (1) the computation of the responses of subsystems, given the input subsystem support motion for components and systems whose failure can lead to an accident sequence (radioactive release), and (2) the results of a sensitivity study undertaken to determine the contributions of the several links in the seismic methodology chain (SMC) - seismic input (SI), soil-structure interaction (SSI), structure response (STR), and subsystem response (SUB) - to the uncertainty in subsystem response.

  5. A method of investigating the phase response characteristic of the ionospheric scattering communications channel

    NASA Technical Reports Server (NTRS)

    Yakovets, A. F.

    1972-01-01

    A method is proposed for measuring the phase difference fluctuations between vibrations at different frequencies that result from scattering properties of the medium. The measurement equipment is described, along with an ideal communication channel.

  6. Transcriptomic response of Listeria monocytogenes during the transition to the long-term-survival phase.

    PubMed

    Wen, Jia; Deng, Xiangyu; Li, Zengxin; Dudley, Edward G; Anantheswaran, Ramaswamy C; Knabel, Stephen J; Zhang, Wei

    2011-09-01

    Listeria monocytogenes can change its cellular morphology from bacilli to cocci during the transition to the long-term-survival (LTS) phase. The LTS cells demonstrated increased baro- and thermotolerance compared to their vegetative counterparts. So far, the underlying mechanisms that trigger this morphological and physiological transition remain largely unknown. In this study, we compared the transcriptomic profiles of L. monocytogenes serotype 4b strain F2365 at different growth stages in tryptic soy broth with yeast extract (TSBYE) using a whole-genome DNA chip approach. We identified a total of 225 differentially expressed genes (≥4-fold; P < 0.05) during the transition to the LTS phase in TSBYE. Genes related to cell envelope structure, energy metabolism, and transport were most significantly upregulated in the LTS phase. The upregulation of compatible solute transporters may lead to the accumulation of cellular solutes, lowering intracellular water activity and thus increasing bacterial stress resistance during the transition to the LTS phase. The downregulation of genes associated with protein synthesis may indicate a status of metabolic dormancy of the LTS cells. The transcriptomic profiles of resuscitated LTS cells in fresh TSBYE resembled those of log-phase cells (r=0.94), as the LTS cells rapidly resume metabolic activities and transit back to log phase with decreased baro- and thermotolerance. PMID:21764970

  7. Developmental Effects of the ToxCast™ Phase I and Phase II Chemicals in Caenorhabditis elegans and Corresponding Responses in Zebrafish, Rats, and Rabbits

    PubMed Central

    Boyd, Windy A.; Smith, Marjolein V.; Co, Caroll A.; Pirone, Jason R.; Rice, Julie R.; Shockley, Keith R.; Freedman, Jonathan H.

    2015-01-01

    s potential toxicity to humans. Citation: Boyd WA, Smith MV, Co CA, Pirone JR, Rice JR, Shockley KR, Freedman JH. 2016. Developmental effects of the ToxCast™ Phase I and II chemicals in Caenorhabditis elegans and corresponding responses in zebrafish, rats, and rabbits. Environ Health Perspect 124:586–593; http://dx.doi.org/10.1289/ehp.1409645 PMID:26496690

  8. Intrinsic rotation with gyrokinetic models

    SciTech Connect

    Parra, Felix I.; Barnes, Michael; Catto, Peter J.; Calvo, Ivan

    2012-05-15

    The generation of intrinsic rotation by turbulence and neoclassical effects in tokamaks is considered. To obtain the complex dependences observed in experiments, it is necessary to have a model of the radial flux of momentum that redistributes the momentum within the tokamak in the absence of a preexisting velocity. When the lowest order gyrokinetic formulation is used, a symmetry of the model precludes this possibility, making small effects in the gyroradius over scale length expansion necessary. These effects that are usually small become important for momentum transport because the symmetry of the lowest order gyrokinetic formulation leads to the cancellation of the lowest order momentum flux. The accuracy to which the gyrokinetic equation needs to be obtained to retain all the physically relevant effects is discussed.

  9. Modelling the initial phase of the human rod photoreceptor response to the onset of steady illumination.

    PubMed

    Mahroo, Omar A R; Ban, Vin Shen; Bussmann, Benjamin M; Copley, Hannah C; Hammond, Christopher J; Lamb, Trevor D

    2012-04-01

    The initial time course of the change in photoreceptor outer segment membrane conductance in response to light flashes has been modelled using biochemical analysis of phototransduction, and the model has been successfully applied to a range of in vitro recordings and has also been shown to provide a good fit to the leading edge of the electroretinogram a-wave recorded in vivo. We investigated whether a simple modification of the model's equation would predict responses to the onset of steady illumination and tested this against electroretinogram recordings. Scotopic electroretinograms were recorded from three normal human subjects, using conductive fibre electrodes, in response to light flashes (0.30-740 scotopic cd m(-2) s) and to the onset of steady light (11-1,900 scotopic cd m(-2)). Subjects' pupils were dilated pharmacologically. The standard form of the model was applied to flash responses, as in previous studies, to obtain values for the three parameters: maximal response amplitude r (max), sensitivity S and effective delay time t (eff). A new "step response" equation was derived, and this equation provided a good fit to rod responses to steps of light using the same parameter values as for the flash responses. The results support the applicability of the model to the leading edge of electroretinogram responses: in each subject, the model could be used to fit responses both to flashes of light and to the onset of backgrounds with a single set of parameter values.

  10. Planar intrinsic Josephson junctions fabricated on Bi-2212 LPE films

    NASA Astrophysics Data System (ADS)

    Yasuda, Takashi; Kawae, Takeshi; Yamashita, Tsutomu; Taka, Chihiro; Nishida, Akihiko; Takano, Shuzo

    2003-05-01

    Planar design of intrinsic Josephson junctions (IJJs) is studied using Bi2Sr2CaCu2Ox (Bi-2212) films prepared by liquid phase epitaxy. Step-type IJJ stacks fabricated on step-patterned MgO substrates exhibit multibranched current-voltage characteristics inherent in Bi-2212 single crystals. This behavior is found to be limited to films on small-angle steps, suggesting the incorporation of defects near the steep steps of substrates.

  11. Particle-Induced Pulmonary Acute Phase Response Correlates with Neutrophil Influx Linking Inhaled Particles and Cardiovascular Risk

    PubMed Central

    Saber, Anne Thoustrup; Lamson, Jacob Stuart; Jacobsen, Nicklas Raun; Ravn-Haren, Gitte; Hougaard, Karin Sørig; Nyendi, Allen Njimeri; Wahlberg, Pia; Madsen, Anne Mette; Jackson, Petra; Wallin, Håkan; Vogel, Ulla

    2013-01-01

    Background Particulate air pollution is associated with cardiovascular disease. Acute phase response is causally linked to cardiovascular disease. Here, we propose that particle-induced pulmonary acute phase response provides an underlying mechanism for particle-induced cardiovascular risk. Methods We analysed the mRNA expression of Serum Amyloid A (Saa3) in lung tissue from female C57BL/6J mice exposed to different particles including nanomaterials (carbon black and titanium dioxide nanoparticles, multi- and single walled carbon nanotubes), diesel exhaust particles and airborne dust collected at a biofuel plant. Mice were exposed to single or multiple doses of particles by inhalation or intratracheal instillation and pulmonary mRNA expression of Saa3 was determined at different time points of up to 4 weeks after exposure. Also hepatic mRNA expression of Saa3, SAA3 protein levels in broncheoalveolar lavage fluid and in plasma and high density lipoprotein levels in plasma were determined in mice exposed to multiwalled carbon nanotubes. Results Pulmonary exposure to particles strongly increased Saa3 mRNA levels in lung tissue and elevated SAA3 protein levels in broncheoalveolar lavage fluid and plasma, whereas hepatic Saa3 levels were much less affected. Pulmonary Saa3 expression correlated with the number of neutrophils in BAL across different dosing regimens, doses and time points. Conclusions Pulmonary acute phase response may constitute a direct link between particle inhalation and risk of cardiovascular disease. We propose that the particle-induced pulmonary acute phase response may predict risk for cardiovascular disease. PMID:23894396

  12. Toroidal modelling of RMP response in ASDEX Upgrade: coil phase scan, q 95 dependence, and toroidal torques

    NASA Astrophysics Data System (ADS)

    Liu, Yueqiang; Ryan, D.; Kirk, A.; Li, Li; Suttrop, W.; Dunne, M.; Fischer, R.; Fuchs, J. C.; Kurzan, B.; Piovesan, P.; Willensdorfer, M.; the ASDEX Upgrade Team; the EUROfusion MST1 Team

    2016-05-01

    The plasma response to the vacuum resonant magnetic perturbation (RMP) fields, produced by the ELM control coils in ASDEX Upgrade experiments, is computationally modelled using the MARS-F/K codes (Liu et al 2000 Phys. Plasmas 7 3681, Liu et al 2008 Phys. Plasmas 15 112503). A systematic investigation is carried out, considering various plasma and coil configurations as in the ELM control experiments. The low q plasmas, with {{q}95}˜ 3.8 (q 95 is the safety factor q value at 95% of the equilibrium poloidal flux), responding to low n (n is the toroidal mode number) field perturbations from each single row of the ELM coils, generates a core kink amplification effect. Combining two rows, with different toroidal phasing, thus leads to either cancellation or reinforcement of the core kink response, which in turn determines the poloidal location of the peak plasma surface displacement. The core kink response is typically weak for the n  =  4 coil configuration at low q, and for the n  =  2 configuration but only at high q ({{q}95}˜ 5.5 ). A phase shift of around 60 degrees for low q plasmas, and around 90 degrees for high q plasmas, is found in the coil phasing, between the plasma response field and the vacuum RMP field, that maximizes the edge resonant field component. This leads to an optimal coil phasing of about 100 (-100) degrees for low (high) q plasmas, that maximizes both the edge resonant field component and the plasma surface displacement near the X-point of the separatrix. This optimal phasing closely corresponds to the best ELM mitigation observed in experiments. A strong parallel sound wave damping moderately reduces the core kink response but has minor effect on the edge peeling response. For low q plasmas, modelling shows that both the resonant electromagnetic torque and the neoclassical toroidal viscous (NTV) torque (due to the presence of 3D magnetic field perturbations) contribute to the toroidal flow damping, in particular near the

  13. Toroidal modelling of RMP response in ASDEX Upgrade: coil phase scan, q 95 dependence, and toroidal torques

    NASA Astrophysics Data System (ADS)

    Liu, Yueqiang; Ryan, D.; Kirk, A.; Li, Li; Suttrop, W.; Dunne, M.; Fischer, R.; Fuchs, J. C.; Kurzan, B.; Piovesan, P.; Willensdorfer, M.; the ASDEX Upgrade Team; the EUROfusion MST1 Team

    2016-05-01

    The plasma response to the vacuum resonant magnetic perturbation (RMP) fields, produced by the ELM control coils in ASDEX Upgrade experiments, is computationally modelled using the MARS-F/K codes (Liu et al 2000 Phys. Plasmas 7 3681, Liu et al 2008 Phys. Plasmas 15 112503). A systematic investigation is carried out, considering various plasma and coil configurations as in the ELM control experiments. The low q plasmas, with {{q}95}∼ 3.8 (q 95 is the safety factor q value at 95% of the equilibrium poloidal flux), responding to low n (n is the toroidal mode number) field perturbations from each single row of the ELM coils, generates a core kink amplification effect. Combining two rows, with different toroidal phasing, thus leads to either cancellation or reinforcement of the core kink response, which in turn determines the poloidal location of the peak plasma surface displacement. The core kink response is typically weak for the n  =  4 coil configuration at low q, and for the n  =  2 configuration but only at high q ({{q}95}∼ 5.5 ). A phase shift of around 60 degrees for low q plasmas, and around 90 degrees for high q plasmas, is found in the coil phasing, between the plasma response field and the vacuum RMP field, that maximizes the edge resonant field component. This leads to an optimal coil phasing of about 100 (‑100) degrees for low (high) q plasmas, that maximizes both the edge resonant field component and the plasma surface displacement near the X-point of the separatrix. This optimal phasing closely corresponds to the best ELM mitigation observed in experiments. A strong parallel sound wave damping moderately reduces the core kink response but has minor effect on the edge peeling response. For low q plasmas, modelling shows that both the resonant electromagnetic torque and the neoclassical toroidal viscous (NTV) torque (due to the presence of 3D magnetic field perturbations) contribute to the toroidal flow damping, in particular near the

  14. Diverse precerebellar neurons share similar intrinsic excitability.

    PubMed

    Kolkman, Kristine E; McElvain, Lauren E; du Lac, Sascha

    2011-11-16

    The cerebellum dedicates a majority of the brain's neurons to processing a wide range of sensory, motor, and cognitive signals. Stereotyped circuitry within the cerebellar cortex suggests that similar computations are performed throughout the cerebellum, but little is known about whether diverse precerebellar neurons are specialized for the nature of the information they convey. In vivo recordings indicate that firing responses to sensory or motor stimuli vary dramatically across different precerebellar nuclei, but whether this reflects diverse synaptic inputs or differentially tuned intrinsic excitability has not been determined. We targeted whole-cell patch-clamp recordings to neurons in eight precerebellar nuclei which were retrogradely labeled from different regions of the cerebellum in mice. Intrinsic physiology was compared across neurons in the medial vestibular, external cuneate, lateral reticular, prepositus hypoglossi, supragenual, Roller/intercalatus, reticularis tegmenti pontis, and pontine nuclei. Within the firing domain, precerebellar neurons were remarkably similar. Firing faithfully followed temporally modulated inputs, could be sustained at high rates, and was a linear function of input current over a wide range of inputs and firing rates. Pharmacological analyses revealed common expression of Kv3 currents, which were essential for a wide linear firing range, and of SK (small-conductance calcium-activated potassium) currents, which were essential for a wide linear input range. In contrast, membrane properties below spike threshold varied considerably within and across precerebellar nuclei, as evidenced by variability in postinhibitory rebound firing. Our findings indicate that diverse precerebellar neurons perform similar scaling computations on their inputs but may be differentially tuned to synaptic inhibition. PMID:22090493

  15. Unusual biophysics of intrinsically disordered proteins.

    PubMed

    Uversky, Vladimir N

    2013-05-01

    Research of a past decade and a half leaves no doubt that complete understanding of protein functionality requires close consideration of the fact that many functional proteins do not have well-folded structures. These intrinsically disordered proteins (IDPs) and proteins with intrinsically disordered protein regions (IDPRs) are highly abundant in nature and play a number of crucial roles in a living cell. Their functions, which are typically associated with a wide range of intermolecular interactions where IDPs possess remarkable binding promiscuity, complement functional repertoire of ordered proteins. All this requires a close attention to the peculiarities of biophysics of these proteins. In this review, some key biophysical features of IDPs are covered. In addition to the peculiar sequence characteristics of IDPs these biophysical features include sequential, structural, and spatiotemporal heterogeneity of IDPs; their rough and relatively flat energy landscapes; their ability to undergo both induced folding and induced unfolding; the ability to interact specifically with structurally unrelated partners; the ability to gain different structures at binding to different partners; and the ability to keep essential amount of disorder even in the bound form. IDPs are also characterized by the "turned-out" response to the changes in their environment, where they gain some structure under conditions resulting in denaturation or even unfolding of ordered proteins. It is proposed that the heterogeneous spatiotemporal structure of IDPs/IDPRs can be described as a set of foldons, inducible foldons, semi-foldons, non-foldons, and unfoldons. They may lose their function when folded, and activation of some IDPs is associated with the awaking of the dormant disorder. It is possible that IDPs represent the "edge of chaos" systems which operate in a region between order and complete randomness or chaos, where the complexity is maximal. This article is part of a Special Issue

  16. Postpartum Circulating Markers of Inflammation and the Systemic Acute-Phase Response After Early-Onset Preeclampsia.

    PubMed

    van Rijn, Bas B; Bruinse, Hein W; Veerbeek, Jan H; Post Uiterweer, Emiel D; Koenen, Steven V; van der Bom, Johanna G; Rijkers, Ger T; Roest, Mark; Franx, Arie

    2016-02-01

    Preeclampsia is an inflammatory-mediated hypertensive disorder of pregnancy and seems to be an early indicator of increased cardiovascular risk, but mechanisms underlying this association are unclear. In this study, we identified levels of circulating inflammatory markers and dynamic changes in the systemic acute-phase response in 44 women with a history of severe early-onset preeclampsia, compared with 29 controls with only uneventful pregnancies at 1.5 to 3.5 years postpartum. Models used were in vivo seasonal influenza vaccination and in vitro whole-blood culture with T-cell stimulants and the toll-like receptor-4 ligand lipopolysaccharide. Outcome measures were C-reactive protein, interleukin-6 (IL-6), IL-18, fibrinogen, myeloperoxidase, and a panel of 13 cytokines representative of the innate and adaptive inflammatory response, in addition to established cardiovascular markers. The in vivo acute-phase response was higher for women with previous preeclampsia than that for controls without such a history, although only significant for C-reactive protein (P=0.04). Preeclampsia was associated with higher IL-1β (P<0.05) and IL-8 (P<0.01) responses to T-cell activation. Hierarchical clustering revealed 2 distinct inflammatory clusters associated with previous preeclampsia: an adaptive response cluster associated with increased C-reactive protein and IL-6 before and after vaccination, increased weight, and low high-density lipoprotein cholesterol; and a toll-like receptor-4 mediated the cluster associated with increased IL-18 before and after vaccination but not associated with other cardiovascular markers. Furthermore, we found interactions between previous preeclampsia, common TLR4 gene variants, and the IL-18 response to vaccination. In conclusion, preeclampsia is associated with alterations in the inflammatory response postpartum mostly independent of other established cardiovascular risk markers.

  17. Postpartum Circulating Markers of Inflammation and the Systemic Acute-Phase Response After Early-Onset Preeclampsia.

    PubMed

    van Rijn, Bas B; Bruinse, Hein W; Veerbeek, Jan H; Post Uiterweer, Emiel D; Koenen, Steven V; van der Bom, Johanna G; Rijkers, Ger T; Roest, Mark; Franx, Arie

    2016-02-01

    Preeclampsia is an inflammatory-mediated hypertensive disorder of pregnancy and seems to be an early indicator of increased cardiovascular risk, but mechanisms underlying this association are unclear. In this study, we identified levels of circulating inflammatory markers and dynamic changes in the systemic acute-phase response in 44 women with a history of severe early-onset preeclampsia, compared with 29 controls with only uneventful pregnancies at 1.5 to 3.5 years postpartum. Models used were in vivo seasonal influenza vaccination and in vitro whole-blood culture with T-cell stimulants and the toll-like receptor-4 ligand lipopolysaccharide. Outcome measures were C-reactive protein, interleukin-6 (IL-6), IL-18, fibrinogen, myeloperoxidase, and a panel of 13 cytokines representative of the innate and adaptive inflammatory response, in addition to established cardiovascular markers. The in vivo acute-phase response was higher for women with previous preeclampsia than that for controls without such a history, although only significant for C-reactive protein (P=0.04). Preeclampsia was associated with higher IL-1β (P<0.05) and IL-8 (P<0.01) responses to T-cell activation. Hierarchical clustering revealed 2 distinct inflammatory clusters associated with previous preeclampsia: an adaptive response cluster associated with increased C-reactive protein and IL-6 before and after vaccination, increased weight, and low high-density lipoprotein cholesterol; and a toll-like receptor-4 mediated the cluster associated with increased IL-18 before and after vaccination but not associated with other cardiovascular markers. Furthermore, we found interactions between previous preeclampsia, common TLR4 gene variants, and the IL-18 response to vaccination. In conclusion, preeclampsia is associated with alterations in the inflammatory response postpartum mostly independent of other established cardiovascular risk markers. PMID:26711734

  18. Maximising electro-mechanical response by minimising grain-scale strain heterogeneity in phase-change actuator ceramics

    NASA Astrophysics Data System (ADS)

    Oddershede, Jette; Hossain, Mohammad Jahangir; Daniels, John E.

    2016-08-01

    Phase-change actuator ceramics directly couple electrical and mechanical energies through an electric-field-induced phase transformation. These materials are promising for the replacement of the most common electro-mechanical ceramic, lead zirconate titanate, which has environmental concerns. Here, we show that by compositional modification, we reduce the grain-scale heterogeneity of the electro-mechanical response by 40%. In the materials investigated, this leads to an increase in the achievable electric-field-induced strain of the bulk ceramic of 45%. Compositions of (100-x)Bi0.5Na0.5TiO3-(x)BaTiO3, which initially possess a pseudo-cubic symmetry, can be tuned to undergo phase transformations to combined lower symmetry phases, thus decreasing the anisotropy of the transformation strain. Further, modelling of transformation strains of individual grains shows that minimum grain-scale strain heterogeneity can be achieved by precise control of the lattice distortions and orientation distributions of the induced phases. The current results can be used to guide the design of next generation high-strain electro-mechanical ceramic actuator materials.

  19. Hepatic cytochrome P450 3A drug metabolism is reduced in cancer patients who have an acute-phase response

    PubMed Central

    Rivory, L P; Slaviero, K A; Clarke, S J

    2002-01-01

    Inflammatory disease states (infection, arthritis) are associated with reduced drug oxidation by the cytochrome P450 3A system. Many chemotherapy agents are metabolised through this pathway, and disease may therefore influence inter-individual differences in drug pharmacokinetics. The purpose of this study was to assess cytochrome P450 3A function in patients with advanced cancer, and its relation to the acute-phase response. We evaluated hepatic cytochrome P450 3A function in 40 patients with advanced cancer using the erythromycin breath test. Both the traditional C20min measure and the recently proposed 1/TMAX values were estimated. The marker of acute-phase response, C-reactive protein and the pro-inflammatory cytokines IL-6, IL-1β, TNFα and IL-8 were measured in serum or plasma at baseline. Cancer patients with an acute phase response (C-reactive protein >10 mg l−1, n=26) had reduced metabolism as measured with the erythromycin breath test 1/TMAX (Kruskal–Wallis Anova, P=0.0062) as compared to controls (C-reactive protein ⩽10 mg l−1, n=14). Indeed, metabolism was significantly associated with C-reactive protein over the whole concentration range of this acute-phase marker (r=−0.64, Spearman Rank Correlation, P<0.00001). C-reactive protein serum levels were significantly correlated with those of IL-6 (Spearman coefficient=0.58, P<0.0003). The reduction in cytochrome P450 3A function with acute-phase reaction was independent of the tumour type and C-reactive protein elevation was associated with poor performance status. This indicates that the sub-group of cancer patients with significant acute-phase response have compromised drug metabolism, which may have implications for the safety of chemotherapy in this population. British Journal of Cancer (2002) 87, 277–280. doi:10.1038/sj.bjc.6600448 www.bjcancer.com © 2002 Cancer Research UK PMID:12177794

  20. Bimanual motor coordination controlled by cooperative interactions in intrinsic and extrinsic coordinates.

    PubMed

    Sakurada, Takeshi; Ito, Koji; Gomi, Hiroaki

    2016-01-01

    Although strong motor coordination in intrinsic muscle coordinates has frequently been reported for bimanual movements, coordination in extrinsic visual coordinates is also crucial in various bimanual tasks. To explore the bimanual coordination mechanisms in terms of the frame of reference, here we characterized implicit bilateral interactions in visuomotor tasks. Visual perturbations (finger-cursor gain change) were applied while participants performed a rhythmic tracking task with both index fingers under an in-phase or anti-phase relationship in extrinsic coordinates. When they corrected the right finger's amplitude, the left finger's amplitude unintentionally also changed [motor interference (MI)], despite the instruction to keep its amplitude constant. Notably, we observed two specificities: one was large MI and low relative-phase variability (PV) under the intrinsic in-phase condition, and the other was large MI and high PV under the extrinsic in-phase condition. Additionally, using a multiple-interaction model, we successfully decomposed MI into intrinsic components caused by motor correction and extrinsic components caused by visual-cursor mismatch of the right finger's movements. This analysis revealed that the central nervous system facilitates MI by combining intrinsic and extrinsic components in the condition with in-phases in both intrinsic and extrinsic coordinates, and that under-additivity of the effects is explained by the brain's preference for the intrinsic interaction over extrinsic interaction. In contrast, the PV was significantly correlated with the intrinsic component, suggesting that the intrinsic interaction dominantly contributed to bimanual movement stabilization. The inconsistent features of MI and PV suggest that the central nervous system regulates multiple levels of bilateral interactions for various bimanual tasks.

  1. Bimanual motor coordination controlled by cooperative interactions in intrinsic and extrinsic coordinates.

    PubMed

    Sakurada, Takeshi; Ito, Koji; Gomi, Hiroaki

    2016-01-01

    Although strong motor coordination in intrinsic muscle coordinates has frequently been reported for bimanual movements, coordination in extrinsic visual coordinates is also crucial in various bimanual tasks. To explore the bimanual coordination mechanisms in terms of the frame of reference, here we characterized implicit bilateral interactions in visuomotor tasks. Visual perturbations (finger-cursor gain change) were applied while participants performed a rhythmic tracking task with both index fingers under an in-phase or anti-phase relationship in extrinsic coordinates. When they corrected the right finger's amplitude, the left finger's amplitude unintentionally also changed [motor interference (MI)], despite the instruction to keep its amplitude constant. Notably, we observed two specificities: one was large MI and low relative-phase variability (PV) under the intrinsic in-phase condition, and the other was large MI and high PV under the extrinsic in-phase condition. Additionally, using a multiple-interaction model, we successfully decomposed MI into intrinsic components caused by motor correction and extrinsic components caused by visual-cursor mismatch of the right finger's movements. This analysis revealed that the central nervous system facilitates MI by combining intrinsic and extrinsic components in the condition with in-phases in both intrinsic and extrinsic coordinates, and that under-additivity of the effects is explained by the brain's preference for the intrinsic interaction over extrinsic interaction. In contrast, the PV was significantly correlated with the intrinsic component, suggesting that the intrinsic interaction dominantly contributed to bimanual movement stabilization. The inconsistent features of MI and PV suggest that the central nervous system regulates multiple levels of bilateral interactions for various bimanual tasks. PMID:26540267

  2. Study of Hind Limb Tissue Gas Phase Formation in Response to Suspended Adynamia and Hypokinesia

    NASA Technical Reports Server (NTRS)

    Butler, Bruce D.

    1996-01-01

    The purpose of this study was to investigate the hypothesis that reduced joint/muscle activity (hypo kinesia) as well as reduced or null loading of limbs (adynamia) in gravity would result in reduced decompression-induced gas phase and symptoms of decompression sickness (DCS). Finding a correlation between the two phenomena would correspond to the proposed reduction in tissue gas phase formation in astronauts undergoing decompression during extravehicular activity (EVA) in microgravity. The observation may further explain the reported low incidence of DCS in space.

  3. Effects of a beetroot juice with high neobetanin content on the early-phase insulin response in healthy volunteers.

    PubMed

    Wootton-Beard, Peter C; Brandt, Kirsten; Fell, David; Warner, Sarah; Ryan, Lisa

    2014-01-01

    Produce rich in phytochemicals may alter postprandial glucose and insulin responses by interacting with the pathways that regulate glucose uptake and insulin secretion in humans. The aims of the present study were to assess the phytochemical constituents of red beetroot juice and to measure the postprandial glucose and insulin responses elicited by either 225 ml beetroot juice (BEET), a control beverage matched for macronutrient content (MCON) or a glucose beverage in healthy adults. Beetroot juice was a particularly rich source of betalain degradation compounds. The orange/yellow pigment neobetanin was measured in particularly high quantities (providing 1·3 g in the 225 ml). A total of sixteen healthy individuals were recruited, and consumed the test meals in a controlled single-blind cross-over design. Results revealed a significant lowering of the postprandial insulin response in the early phase (0-60 min) (P < 0·05) and a significantly lower glucose response in the 0-30 min phase (P < 0·05) in the BEET treatment compared with MCON. Betalains, polyphenols and dietary nitrate found in the beetroot juice may each contribute to the observed differences in the postprandial insulin concentration. PMID:25191617

  4. In situ observation of the pressure-induced phase transitions of portlandite and influential factors on the pressure response

    NASA Astrophysics Data System (ADS)

    Iizuka, R.; Komatsu, K.; Kagi, H.; Nakano, S.

    2010-12-01

    Pressure-induced structural changes in portlandite, Ca(OH)2, draw attentions as a model system for understanding the behavior of hydrogen bonding in solids. There still remains a discrepancy in the pressure response of portlandite among the previous studies. A crystal-to-crystal phase transition or a pressure-induced amorphization occurs at 8-12 GPa at room temperature in powder samples in various pressure transmitting media [Meade and Jeanloz. 1990; Catalli et al., 2008 etc.], whereas a single crystal transforms to a high-pressure (high-P) form at 6 GPa [Ekbundit et al., 1996]. So far, the relationship between the phase transition mechanism and influential factors as possible driving forces, such as the grain size, the hydrostatic condition and the isotope effect, has not been fully established yet. In this study, pressure-responses of synthesized single crystals and powder of portlandite were investigated using diamond anvil cells under quasi-hydrostatic conditions. Powder samples of Ca(OH)2 were synthesized by dissolving CaO in H2O. Single crystal was obtained by recrystallization from the synthesized powder sample with excess H2O on the glass plates in a desiccator. Raman spectra, IR spectra and X-ray diffraction (XRD) measurements were conducted up to 25 GPa using a 4:1 methanol-ethanol mixture or helium was used as a pressure medium. Applied pressure and the hydrostaticity were estimated by ruby fluorescence. Angle-dispersive powder X-ray diffraction patterns were measured at the beamline 18C, Photon Factory, KEK. Single crystal XRD was measured using a micro focused X-ray diffractometer (MicroMax-007, Rigaku) with confocal multi layer mirrors. Our results show that both the grain size and the hydrostaticity serve independently as influential factors on the phase transition pressure and the process toward the subsequent amorphization. We first observed the difference in the phase transition pressure between Ca(OH)2 and Ca(OD)2 single crystals in helium

  5. Intrinsic motivation in a competitive setting.

    PubMed

    Weinberg, R S

    1979-01-01

    The purpose of the present investigation was to determine the effects of success-failure and monetary reward on intrinsic motivation of males and females competing on a motor task. Results indicated a significant main effect for feedback with subjects exhibiting more intrinsic motivation after success than after failure. The Sex x Feedback interaction showed that males displayed more intrinsic motivation than females after success whereas females exhibited more intrinsic motivation than males after failure. Results are discussed in terms of Deci's cognitive evaluation theory and sex-role appropriate behaviors for males and females. Implications for competitive physical activity are drawn.

  6. Issues in Purchasing and Maintaining Intrinsic Standards

    SciTech Connect

    PETTIT,RICHARD B.; JAEGER,KLAUS; EHRLICH,CHARLES D.

    2000-09-12

    Intrinsic standards are widely used in the metrology community because they realize the best level uncertainty for many metrology parameters. For some intrinsic standards, recommended practices have been developed to assist metrologists in the selection of equipment and the development of appropriate procedures in order to realize the intrinsic standard. As with the addition of any new standard, the metrology laboratory should consider the pros and cons relative to their needs before purchasing the standard so that the laboratory obtains the maximum benefit from setting up and maintaining these standards. While the specific issues that need to be addressed depend upon the specific intrinsic standard and the level of realization, general issues that should be considered include ensuring that the intrinsic standard is compatible with the laboratory environment, that the standard is compatible with the current and future workload, and whether additional support standards will be required in order to properly maintain the intrinsic standard. When intrinsic standards are used to realize the best level of uncertainty for a specific metrology parameter, they usually require critical and important maintenance activities. These activities can including training of staff in the system operation, as well as safety procedures; performing periodic characterization measurements to ensure proper system operation; carrying out periodic intercomparisons with similar intrinsic standards so that proper operation is demonstrated; and maintaining control or trend charts of system performance. This paper has summarized many of these important issues and therefore should be beneficial to any laboratory that is considering the purchase of an intrinsic standard.

  7. Human phase response curve to a single 6.5 h pulse of short-wavelength light

    PubMed Central

    Rüger, Melanie; St Hilaire, Melissa A; Brainard, George C; Khalsa, Sat-Bir S; Kronauer, Richard E; Czeisler, Charles A; Lockley, Steven W

    2013-01-01

    The photic resetting response of the human circadian pacemaker depends on the timing of exposure, and the direction and magnitude of the resulting shift is described by a phase response curve (PRC). Previous PRCs in humans have utilized high-intensity polychromatic white light. Given that the circadian photoreception system is maximally sensitive to short-wavelength visible light, the aim of the current study was to construct a PRC to blue (480 nm) light and compare it to a 10,000 lux white light PRC constructed previously using a similar protocol. Eighteen young healthy participants (18–30 years) were studied for 9–10 days in a time-free environment. The protocol included three baseline days followed by a constant routine (CR) to assess initial circadian phase. Following this CR, participants were exposed to a 6.5 h 480 nm light exposure (11.8 μW cm−2, 11.2 lux) following mydriasis via a modified Ganzfeld dome. A second CR was conducted following the light exposure to re-assess circadian phase. Phase shifts were calculated from the difference in dim light melatonin onset (DLMO) between CRs. Exposure to 6.5 h of 480 nm light resets the circadian pacemaker according to a conventional type 1 PRC with fitted maximum delays and advances of −2.6 h and 1.3 h, respectively. The 480 nm PRC induced ∼75% of the response of the 10,000 lux white light PRC. These results may contribute to a re-evaluation of dosing guidelines for clinical light therapy and the use of light as a fatigue countermeasure. PMID:23090946

  8. Response of Global Lightning Activity Observed by the TRMM/LIS During Warm and Cold ENSO Phases

    NASA Technical Reports Server (NTRS)

    Chronis, Themis G.; Cecil, Dan; Goodman, Steven J.; Buechler, Dennis

    2007-01-01

    This paper investigates the response of global lightning activity to the transition from the warm (January February March-JFM 1998) to the cold (JFM 1999) ENSO phase. The nine-year global lightning climatology for these months from the Tropical Rainfall Measuring Mission (TRMM) Lightning Imaging Sensor (LIS) provides the observational baseline. Flash rate density is computed on a 5.0x5.0 degree lat/lon grid within the LIS coverage area (between approx.37.5 N and S) for each three month period. The flash rate density anomalies from this climatology are examined for these months in 1998 and 1999. The observed lightning anomalies spatially match the documented general circulation features that accompany the warm and cold ENSO events. During the warm ENSO phase the dominant positive lightning anomalies are located mostly over the Western Hemisphere and more specifically over Gulf of Mexico, Caribbean and Northern Mid-Atlantic. We further investigate specifically the Northern Mid-Atlantic related anomaly features since these show strong relation to the North Atlantic Oscillation (NAO). Furthermore these observed anomaly patterns show strong spatial agreement with anomalous upper level (200 mb) cold core cyclonic circulations. Positive sea surface temperature anomalies during the warm ENSO phase also affect the lightning activity, but this is mostly observed near coastal environments. Over the open tropical oceans, there is climatologically less lightning and the anomalies are less pronounced. Warm ENSO related anomalies over the Eastern Hemisphere are most prominent over the South China coast. The transition to the cold ENSO phase illustrates the detected lightning anomalies to be more pronounced over East and West Pacific. A comparison of total global lightning between warm and cold ENSO phase reveals no significant difference, although prominent regional anomalies are located over mostly oceanic environments. All three tropical "chimneys" (Maritime Continent, Central

  9. Early weaning alters the acute phase immune response to an endotoxin challenge in beef cattle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Previous research indicates that early weaning prior to shipment can reduce transportation-induced increases in acute phase proteins (APP), and can increase subsequent performance in the feedlot. These data suggest that the combination of weaning and transport stress may compromise the immune system...

  10. Early weaning alters the acute phase response to an endotoxin challenge in beef calves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Previous research indicates that early weaning prior to shipment can reduce transportation-induced increases in acute phase proteins (APP), and can increase subsequent performance in the feedlot. These data suggest that the combination of weaning and transport stress may compromise the immune system...

  11. Dynamic iso-resistive trunk extension simulation: contributions of the intrinsic and reflexive mechanisms to spinal stability.

    PubMed

    Davarani, S Zeinali; Shirazi-Adl, A; Hemami, H; Mousavi, S J; Parnianpour, M

    2007-01-01

    The effects of external resistance on the recruitment of trunk muscles and the role of intrinsic and reflexive mechanisms to ensure the spinal stability are significant issues in spinal biomechanics. A computational model of spine under the control of 48 anatomically oriented muscle actions was used to simulate iso-resistive trunk movements. Neural excitation of muscles was attained based on inverse dynamics approach along with the stability-based optimization. The effect of muscle spindle reflex response on the trunk movement stability was evaluated upon the application of a perturbation moment. In this study, the trunk extension movement at various resistance levels while extending from 60 degrees flexion to the upright posture was investigated. Incorporation of the stability condition as an additional constraint in the optimization algorithm increased antagonistic activities for all resistance levels demonstrating that the co-activation caused an increase in the intrinsic stiffness of the spine and its stability in a feed-forward manner. During the acceleration phase of the movement, extensors activity increased while flexors activity decreased in response to the higher resistance. The co-activation ratio noticed in the braking phase of the movement increased with higher resistance. In presence of a 30 Nm flexion perturbation moment, reflexive feed-back noticeably decreased the induced deviation of the velocity and position profiles from the desired ones at all resistance levels. The stability-generated co-activation decreased the reflexive response of muscle spindles to the perturbation demonstrating that both intrinsic and reflexive mechanisms contribute to the trunk stability. The rise in muscle co-activation can ameliorate the corruption of afferent neural sensory system at the expense of higher loading of the spine.

  12. Intrinsic Localized Modes in Proteins

    PubMed Central

    Nicolaï, Adrien; Delarue, Patrice; Senet, Patrick

    2015-01-01

    Protein dynamics is essential for proteins to function. Here we predicted the existence of rare, large nonlinear excitations, termed intrinsic localized modes (ILMs), of the main chain of proteins based on all-atom molecular dynamics simulations of two fast-folder proteins and of a rigid α/β protein at 300 K and at 380 K in solution. These nonlinear excitations arise from the anharmonicity of the protein dynamics. The ILMs were detected by computing the Shannon entropy of the protein main-chain fluctuations. In the non-native state (significantly explored at 380 K), the probability of their excitation was increased by a factor between 9 and 28 for the fast-folder proteins and by a factor 2 for the rigid protein. This enhancement in the non-native state was due to glycine, as demonstrated by simulations in which glycine was mutated to alanine. These ILMs might play a functional role in the flexible regions of proteins and in proteins in a non-native state (i.e. misfolded or unfolded states). PMID:26658321

  13. Intrinsically photosensitive retinal ganglion cells.

    PubMed

    Do, Michael Tri Hoang; Yau, King-Wai

    2010-10-01

    Life on earth is subject to alternating cycles of day and night imposed by the rotation of the earth. Consequently, living things have evolved photodetective systems to synchronize their physiology and behavior with the external light-dark cycle. This form of photodetection is unlike the familiar "image vision," in that the basic information is light or darkness over time, independent of spatial patterns. "Nonimage" vision is probably far more ancient than image vision and is widespread in living species. For mammals, it has long been assumed that the photoreceptors for nonimage vision are also the textbook rods and cones. However, recent years have witnessed the discovery of a small population of retinal ganglion cells in the mammalian eye that express a unique visual pigment called melanopsin. These ganglion cells are intrinsically photosensitive and drive a variety of nonimage visual functions. In addition to being photoreceptors themselves, they also constitute the major conduit for rod and cone signals to the brain for nonimage visual functions such as circadian photoentrainment and the pupillary light reflex. Here we review what is known about these novel mammalian photoreceptors. PMID:20959623

  14. Unusual Electro-Optic Kerr Response in a Self-Stabilized Amorphous Blue Phase with Nanoscale Smectic Clusters.

    PubMed

    Le, Khoa V; Hafuri, Miho; Ocak, Hale; Bilgin-Eran, Belkız; Tschierske, Carsten; Sasaki, Takeo; Araoka, Fumito

    2016-05-18

    We investigated the electro-optic response in the "foggy" amorphous blue phase (BPIII) as well as in the isotropic phase. To the best of our knowledge, such a study has not yet been performed due to the very limited thermal range of BPIII. In this study, we used a single-component chiral bent-core liquid crystal with a self-stabilized BPIII, which is stable over a wide temperature range. The results show that the response time is on the order of hundreds of microseconds in the isotropic phase and increases to 1-2 ms in the BPIII (at TI-BP -T <1), then drastically increases up to a few tens of milliseconds upon further cooling in BPIII. Such an unusual behavior was explained on the basis of the high rotational viscosity and/or the existence of nanoscale smectic (Sm) clusters. The Kerr constant was also measured and found to be ∼500 pm V(-2) , which is the largest among bent-core BP systems reported so far and comparable with that of polymer-stabilized BPs.

  15. Lipopolysaccharide binding protein and serum amyloid A secretion by human intestinal epithelial cells during the acute phase response.

    PubMed

    Vreugdenhil, A C; Dentener, M A; Snoek, A M; Greve, J W; Buurman, W A

    1999-09-01

    The acute phase proteins LPS binding protein (LBP) and serum amyloid A (SAA) are produced by the liver and are present in the circulation. Both proteins have been shown to participate in the immune response to endotoxins. The intestinal mucosa forms a large surface that is continuously exposed to these microbial products. By secretion of antimicrobial and immunomodulating agents, the intestinal epithelium contributes to the defense against bacteria and their products. The aim of this study was to explore the influence of the inflammatory mediators TNF-alpha, IL-6, and IL-1beta on the release of LBP and SAA by intestinal epithelial cells (IEC). In addition, the induction of LBP and SAA release by cell lines of intestinal epithelial cells and hepatic cells was compared. The data obtained show that in addition to liver cells, IEC also expressed LBP mRNA and released bioactive LBP and SAA upon stimulation. Regulation of LBP and SAA release by IEC and hepatocytes was typical for class 1 acute phase proteins, although differences in regulation between the cell types were observed. Endotoxin did not induce LBP and SAA release. Glucocorticoids were demonstrated to strongly enhance the cytokine-induced release of LBP and SAA by IEC, corresponding to hepatocytes. The data from this study, which imply that human IEC can produce LBP and SAA, suggest a role for these proteins in the local defense mechanism of the gut to endotoxin. Furthermore, the results demonstrate that tissues other than the liver are involved in the acute phase response.

  16. Intrinsic structural defects in monolayer molybdenum disulfide

    SciTech Connect

    Zhou, Wu; Idrobo Tapia, Juan C

    2013-01-01

    Monolayer molybdenum disulfide (MoS2) is a two-dimensional direct band gap semiconductor with distinctive mechanical, electronic, optical and chemical properties that can be utilized for novel nanoelectronics and optoelectronics devices. The performance of these electronic devices strongly depends on the quality and defect morphology of the MoS2 layers. Yet, little is known about the atomic structure of defects present in monolayer MoS2 and their influences on the material properties. Here we provide a systematic study of various intrinsic structural defects, including point defects, grain boundaries, and edges, in chemical vapor phase grown monolayer MoS2 via direct atomic resolution imaging, and explore their energy landscape and electronic properties using first-principles calculations. We discover that one-dimensional metallic wires can be created via two different types of 60 grain boundaries consisting of distinct 4-fold ring chains. A new type of edge reconstruction, representing a transition state during growth, was also identified, providing insights into the material growth mechanism. The atomic scale study of structural defects presented here brings new opportunities to tailor the properties of MoS2 via controlled synthesis and defect engineering.

  17. Dasatinib induces fast and deep responses in newly diagnosed chronic myeloid leukaemia patients in chronic phase: clinical results from a randomised phase-2 study (NordCML006)

    PubMed Central

    Hjorth-Hansen, Henrik; Stenke, Leif; Söderlund, Stina; Dreimane, Arta; Ehrencrona, Hans; Gedde-Dahl, Tobias; Gjertsen, Bjørn Tore; Höglund, Martin; Koskenvesa, Perttu; Lotfi, Kourosh; Majeed, Waleed; Markevärn, Berit; Ohm, Lotta; Olsson-Strömberg, Ulla; Remes, Kari; Suominen, Merja; Simonsson, Bengt; Porkka, Kimmo; Mustjoki, Satu; Richter, Johan

    2015-01-01

    We randomised 46 newly diagnosed patients with chronic myeloid leukaemia (median age 56) to receive dasatinib 100 mg QD or imatinib 400 mg QD and report outcome as an intention-to-treat analysis with 36 months follow-up. Early cytogenetic and molecular responses were superior in the dasatinib group, with a tendency that imatinib patients caught up with time. For instance, MR3.0 was reached at 3 months in 36% vs. 8% (P = 0.02), at 12 months in 81% vs. 46% (P = 0.02) and at 18 months in 73% vs. 65% (n.s.) of the patients in the two groups. In contrast, MR4.5 was consistently superior in the dasatinib group at all time points from 6 months onwards, reaching 61% vs. 21% (P < 0.05) at 36 months. Sixty-four vs. 71% of the patients in the dasatinib and imatinib arms, respectively, remained on assigned drug. Dasatinib dose was frequently reduced, but with maintained excellent effect. One imatinib patient progressed to blastic phase, but no CML-related deaths occurred. In conclusion, our data compare favourably with those of the dasatinib registration study, DASISION. The fast and deep molecular responses induced by dasatinib compared with imatinib may be exploited to increase the proportion of patients who can achieve a treatment-free remission after treatment discontinuation. PMID:25082346

  18. Effect of varying the oil phase on the behavior of pH-responsive latex-based emulsifiers: demulsification versus transitional phase inversion.

    PubMed

    Read, E S; Fujii, S; Amalvy, J I; Randall, D P; Armes, S P

    2004-08-31

    Sterically stabilized polystyrene latexes (previously described by Amalvy, J. I.; et al. Chem. Commun. 2003, 1826) were evaluated as pH-responsive particulate emulsifiers for the preparation of both oil-in-water and water-in-oil emulsions. The steric stabilizer was a well-defined AB diblock copolymer where A is poly(2-(dimethylamino)ethyl methacrylate) and B is poly(methyl methacrylate). Several parameters were varied during the emulsion preparation, including the polarity of the oil phase, the latex concentration, surface concentration of copolymer stabilizer, and solution pH. Nonpolar oils such as n-dodecane gave oil-in-water emulsions, and polar oils such as 1-undecanol produced water-in-oil emulsions. In both cases, these emulsions proved to be stimulus-responsive: demulsification occurred rapidly on adjusting the solution pH. Oils of intermediate polarity such as methyl myristate or cineole led to emulsions that underwent transitional inversion on adjusting the solution pH. All emulsions were polydisperse and typically ranged from 40 to 400 microm diameter, as judged by optical microscopy and Malvern Mastersizer measurements. Critical point drying of the emulsion droplets, followed by scanning electron microscopy studies, confirmed that the latex particles were adsorbed as a single monolayer at the oil/water interface, as anticipated.

  19. Shock response and phase transitions of MgO at planetary impact conditions

    DOE PAGESBeta

    Root, Seth; Shulenburger, Luke; Lemke, Raymond W.; Dolan, Daniel H.; Mattsson, Thomas R.; Desjarlais, Michael P.

    2015-11-04

    The moon-forming impact and the subsequent evolution of the proto-Earth is strongly dependent on the properties of materials at the extreme conditions generated by this violent collision. We examine the high pressure behavior of MgO, one of the dominant constituents in Earth’s mantle, using high-precision, plate impact shock compression experiments performed on Sandia National Laboratories’ Z Machine and extensive quantum calculations using density functional theory (DFT) and quantum Monte Carlo (QMC) methods. The combined data span from ambient conditions to 1.2 TPa and 42,000 K, showing solid-solid and solid-liquid phase boundaries. Furthermore our results indicate that under impact the solidmore » and liquid phases coexist for more than 100 GPa, pushing complete melting to pressures in excess of 600 GPa. Furthermore, the high pressure required for complete shock melting has implications for a broad range of planetary collision events.« less

  20. Phase behavior and unusual dynamics of stimuli-responsive microgel colloids

    NASA Astrophysics Data System (ADS)

    Tata, B. V. R.

    2013-02-01

    Monodisperse poly (N-isopropylacrylamide) (PNIPAM) microgel particles in aqueous medium exhibit structural ordering similar to that observed in atomic systems. Colloidal crystals of these microgel particles exhibit series of phase transitions with increase in temperature due to reduction in the particle size and variation in the interparticle interactions. Unlike hard-sphere or charged colloidal particles, microgel particles are heterogeneous in particle density with dense solvent penetrable polymer core and brush-like polymer chains forming a shell. In this talk I will present static/dynamic light scattering, confocal microscopy and UV-Visible spectroscopy results on dense microgel suspensions exhibiting unusual dynamics across melting, tunabilty of Bragg diffraction, particle distribution and nature of interparticle interaction upon osmotic compression. From these results I conclude that PNIPAM microgel sphere are not only soft but also compressible and differ from other hard-sphere and charged colloidal systems in significant way in their structure, dynamics and phase behaviour.

  1. Shock Response and Phase Transitions of MgO at Planetary Impact Conditions

    NASA Astrophysics Data System (ADS)

    Root, Seth; Shulenburger, Luke; Lemke, Raymond W.; Dolan, Daniel H.; Mattsson, Thomas R.; Desjarlais, Michael P.

    2015-11-01

    The moon-forming impact and the subsequent evolution of the proto-Earth is strongly dependent on the properties of materials at the extreme conditions generated by this violent collision. We examine the high pressure behavior of MgO, one of the dominant constituents in Earth's mantle, using high-precision, plate impact shock compression experiments performed on Sandia National Laboratories' Z Machine and extensive quantum calculations using density functional theory (DFT) and quantum Monte Carlo (QMC) methods. The combined data span from ambient conditions to 1.2 TPa and 42 000 K, showing solid-solid and solid-liquid phase boundaries. Furthermore our results indicate that under impact the solid and liquid phases coexist for more than 100 GPa, pushing complete melting to pressures in excess of 600 GPa. The high pressure required for complete shock melting has implications for a broad range of planetary collision events.

  2. Phase transition of a disordered nuage protein generates environmentally responsive membraneless organelles.

    PubMed

    Nott, Timothy J; Petsalaki, Evangelia; Farber, Patrick; Jervis, Dylan; Fussner, Eden; Plochowietz, Anne; Craggs, Timothy D; Bazett-Jones, David P; Pawson, Tony; Forman-Kay, Julie D; Baldwin, Andrew J

    2015-03-01

    Cells chemically isolate molecules in compartments to both facilitate and regulate their interactions. In addition to membrane-encapsulated compartments, cells can form proteinaceous and membraneless organelles, including nucleoli, Cajal and PML bodies, and stress granules. The principles that determine when and why these structures form have remained elusive. Here, we demonstrate that the disordered tails of Ddx4, a primary constituent of nuage or germ granules, form phase-separated organelles both in live cells and in vitro. These bodies are stabilized by patterned electrostatic interactions that are highly sensitive to temperature, ionic strength, arginine methylation, and splicing. Sequence determinants are used to identify proteins found in both membraneless organelles and cell adhesion. Moreover, the bodies provide an alternative solvent environment that can concentrate single-stranded DNA but largely exclude double-stranded DNA. We propose that phase separation of disordered proteins containing weakly interacting blocks is a general mechanism for forming regulated, membraneless organelles. PMID:25747659

  3. Shock response and phase transitions of MgO at planetary impact conditions

    SciTech Connect

    Root, Seth; Shulenburger, Luke; Lemke, Raymond W.; Dolan, Daniel H.; Mattsson, Thomas R.; Desjarlais, Michael P.

    2015-11-04

    The moon-forming impact and the subsequent evolution of the proto-Earth is strongly dependent on the properties of materials at the extreme conditions generated by this violent collision. We examine the high pressure behavior of MgO, one of the dominant constituents in Earth’s mantle, using high-precision, plate impact shock compression experiments performed on Sandia National Laboratories’ Z Machine and extensive quantum calculations using density functional theory (DFT) and quantum Monte Carlo (QMC) methods. The combined data span from ambient conditions to 1.2 TPa and 42,000 K, showing solid-solid and solid-liquid phase boundaries. Furthermore our results indicate that under impact the solid and liquid phases coexist for more than 100 GPa, pushing complete melting to pressures in excess of 600 GPa. Furthermore, the high pressure required for complete shock melting has implications for a broad range of planetary collision events.

  4. Stable response of axisymmetric two-phase water-saturated soil.

    PubMed

    Cai, Yuan-qiang; Meng, Kai; Xu, Chang-jie

    2004-09-01

    Biot's dynamic consolidation equations and Hankel transform were used to derive the integral solutions of stress and displacement for axisymmetric harmonic excitations in the two-phase saturated soil with subjacent rock-stratum. The influence of the coefficient of permeability and loading frequency on the soil displacement at the ground surface were studied. The results showed that higher loading frequency led to more dynamic characteristics; and that the effect of the soil permeability was more obvious at higher frequencies.

  5. Response of a catalytic reaction to periodic variation of the CO pressure: increased CO2 production and dynamic phase transition.

    PubMed

    Machado, Erik; Buendía, Gloria M; Rikvold, Per Arne; Ziff, Robert M

    2005-01-01

    We present a kinetic Monte Carlo study of the dynamical response of a Ziff-Gulari-Barshad model for CO oxidation with CO desorption to periodic variation of the CO pressure. We use a square-wave periodic pressure variation with parameters that can be tuned to enhance the catalytic activity. We produce evidence that, below a critical value of the desorption rate, the driven system undergoes a dynamic phase transition between a CO2 productive phase and a nonproductive one at a critical value of the period and waveform of the pressure oscillation. At the dynamic phase transition the period-averaged CO2 production rate is significantly increased and can be used as a dynamic order parameter. We perform a finite-size scaling analysis that indicates the existence of power-law singularities for the order parameter and its fluctuations, yielding estimated critical exponent ratios beta/nu approximately 0.12 and gamma/nu approximately 1.77. These exponent ratios, together with theoretical symmetry arguments and numerical data for the fourth-order cumulant associated with the transition, give reasonable support for the hypothesis that the observed nonequilibrium dynamic phase transition is in the same universality class as the two-dimensional equilibrium Ising model.

  6. Comparison of gamma-gamma Phase Coarsening Responses of Three Powder Metal Disk Superalloys

    NASA Technical Reports Server (NTRS)

    Gabb, T. P.; Gayda, J.; Johnson, D. F.; MacKay, R. A.; Rogers, R. B.; Sudbrack, C. K.; Garg, A.; Locci, I. E.; Semiatin, S. L.; Kang, E.

    2016-01-01

    The phase microstructures of several powder metal (PM) disk superalloys were quantitatively evaluated. Contents, chemistries, and lattice parameters of gamma and gamma strengthening phase were determined for conventionally heat treated Alloy 10, LSHR, and ME3 superalloys, after electrolytic phase extractions. Several of long term heat treatments were then performed, to allow quantification of the precipitation, content, and size distribution of gamma at a long time interval to approximate equilibrium conditions. Additional coarsening heat treatments were performed at multiple temperatures and shorter time intervals, to allow quantification of the precipitation, contents and size distributions of gamma at conditions diverging from equilibrium. Modest differences in gamma and gamma lattice parameters and their mismatch were observed among the alloys, which varied with heat treatment. Yet, gamma coarsening rates were very similar for all three alloys in the heat treatment conditions examined. Alloy 10 had higher gamma dissolution and formation temperatures than LSHR and ME3, but a lower lattice mismatch, which was slightly positive for all three alloys at room temperature. The gamma precipitates of Alloy 10 appeared to remain coherent at higher temperatures than for LSHR and ME3. Higher coarsening rates were observed for gamma precipitates residing along grain boundaries than for those within grains in all three alloys, during slow-moderate quenching from supersolvus solution heat treatments, and during aging at temperatures of 843 C and higher.

  7. Intrinsic vs. extrinsic controls on channel evolution in a sub-tropical river, Australia

    NASA Astrophysics Data System (ADS)

    Daley, James; Croke, Jacky; Thompson, Chris; Cohen, Tim; Macklin, Mark; Sharma, Ashneel

    2016-04-01

    Palaeohydrological research provides valuable insights to the understanding of short- and long-term fluvial dynamics in response to climate change and tectonic activity. In landscapes where tectonic activity is minimal fluvial archives record long-term changes in sediment and discharge dynamics related to either intrinsic or extrinsic controls. Isolating the relative controls of these factors is an important frontier in this area of research. Advances in geochronology, the acquisition of high resolution topographic data and geomorphological techniques provide an opportunity to assess the relative importance of intrinsic and extrinsic controls on terrace and floodplain formation. This study presents the results of detailed chrono-stratigraphic research in a partly confined river valley in subtropical southeast Queensland. River systems within this region are characterized by high hydrological variability and have a near-ubiquitous compound channel morphology (macrochannel) where Holocene deposits are inset within late Pleistocene terraces. These macrochannels can accommodate floods up to and beyond the predicted 100-year flood. Using single grain optically stimulated luminescence and radiocarbon analyses, combined with high resolution spatial datasets, we demonstrate the nature of fluvial response to major late Quaternary climate change. A large proportion of the valley floor is dominated by terrace alluvium deposited after the Last Glacial Maximum (LGM) (17 - 13 ka) and overlies basal older Pleistocene alluvium. Preliminary results suggest a phase of incision occurred at 10 ka with the formation of the large alluvial trench. The Holocene floodplain is dominated by processes of catastrophic vertical accretion and erosion (cut-and-fill) and oblique accretion at the macrochannel margins. The consistency in ages for the terraces and subsequent incision suggests a uniform network response. Alluvial sediments and channel configuration in this compound and complex

  8. Phase-dependent justification: the role of personal responsibility in fair healthcare.

    PubMed

    Bærøe, Kristine; Cappelen, Cornelius

    2015-10-01

    The main aim of this paper is to examine the fairness of different ways of holding people responsible for healthcare-related choices. Our focus is on conceptualisations of responsibility that involve blame and sanctions, and our analytical approach is to provide a systematic discussion based on interrelated and successive health-related, lifestyle choices of an individual. We assess the already established risk-sharing, backward-looking and forward-looking views on responsibility according to a variety of standard objections. In conclusion, all of the proposed views on holding people responsible for their lifestyle choices are subjected to reasonable critiques, although the risk-sharing view fare considerably better than the others overall considered. With our analytical approach, we are able to identify how basic conditions for responsibility ascription alter along a time axis. Repeated relapses with respect to healthcare associated with persistent, unhealthy lifestyle choices, call for distinct attention. In such situations, contextualised reasoning and transparent policy-making, rather than opaque clinical judgements, are required as steps towards fair allocation of healthcare resources. PMID:26269464

  9. Phase-dependent justification: the role of personal responsibility in fair healthcare.

    PubMed

    Bærøe, Kristine; Cappelen, Cornelius

    2015-10-01

    The main aim of this paper is to examine the fairness of different ways of holding people responsible for healthcare-related choices. Our focus is on conceptualisations of responsibility that involve blame and sanctions, and our analytical approach is to provide a systematic discussion based on interrelated and successive health-related, lifestyle choices of an individual. We assess the already established risk-sharing, backward-looking and forward-looking views on responsibility according to a variety of standard objections. In conclusion, all of the proposed views on holding people responsible for their lifestyle choices are subjected to reasonable critiques, although the risk-sharing view fare considerably better than the others overall considered. With our analytical approach, we are able to identify how basic conditions for responsibility ascription alter along a time axis. Repeated relapses with respect to healthcare associated with persistent, unhealthy lifestyle choices, call for distinct attention. In such situations, contextualised reasoning and transparent policy-making, rather than opaque clinical judgements, are required as steps towards fair allocation of healthcare resources.

  10. Similarities in acute phase protein response during hibernation in black bears and major depression in humans: A response to underlying metabolic depression?

    USGS Publications Warehouse

    Tsiouris, J.A.; Chauhan, V.P.S.; Sheikh, A.M.; Chauhan, A.; Malik, M.; Vaughan, M.R.

    2004-01-01

    This study investigated the effects of hibernation with mild hypothermia and the stress of captivity on levels of six acute-phase proteins (APPs) in serial samples of serum from 11 wild and 6 captive black bears (Ursus americanus Pallas, 1780) during active and hibernating states. We hypothesize that during hibernation with mild hypothermia, bears would show an APP response similar to that observed in major depression. Enzyme-linked immunoabsorbent assay was used to measure alpha2-macroglobulin and C-reactive protein, and a nephelometer to measure alpha1-antitrypsin, haptoglobin, ceruloplasmin, and transferrin. Levels of all other proteins except ceruloplasmin were significantly elevated during hibernation in both wild and captive bears at the p < 0.05 to p < 0.001 level. Alpha 2-macroglobulin and C-reactive-protein levels were increased in captive versus wild bears in both active and hibernating states at the p < 0.01 to p < 0.0001 level. During hibernation with mild hypothermia, black bears do not show immunosuppression, but show an increased APP response similar to that in patients with major depression. This APP response is explained as an adaptive response to the underlying metabolic depression in both conditions. Metabolic depression in hibernating bears is suggested as a natural model for research to explain the neurobiology of depression.

  11. An investigation of wing buffeting response at subsonic and transonic speeds. Phase 2: F-111A flight data analysis. Volume 1: Summary of technical approach, results and conclusions

    NASA Technical Reports Server (NTRS)

    Benepe, D. B.; Cunningham, A. M., Jr.; Traylor, S., Jr.; Dunmyer, W. D.

    1978-01-01

    A detailed investigation of the flight buffeting response of the F-111A was performed in two phases. In Phase 1 stochastic analysis techniques were applied to wing and fuselage responses for maneuvers flown at subsonic speeds and wing leading edge sweep of 26 degrees. Power spectra and rms values were obtained. This report gives results of Phase 2 where the analyses were extended to include maneuvers flown at wing leading edge sweep values of 50 and 75.5 degrees at subsonic and supersonic speeds and the responses examined were expanded to include vertical shear, bending moment, and hingeline torque of the left and right horizontal tails. Power spectra, response time histories, variations of rms response with angle of attack and effects of wing sweep and Mach number are presented and discussed. Some Phase 1 results are given for comparison purposes.

  12. Intrinsic bioremediation of landfills interim report

    SciTech Connect

    Brigmon, R.L.; Fliermans, C.B.

    1997-07-14

    Intrinsic bioremediation is a risk management option that relies on natural biological and physical processes to contain the spread of contamination from a source. Evidence is presented in this report that intrinsic bioremediation is occurring at the Sanitary Landfill is fundamental to support incorportion into a Corrective Action Plan (CAP).

  13. The detrimental effects of extrinsic reinforcement on "Intrinsic motivation".

    PubMed

    Dickinson, A M

    1989-01-01

    Extrinsic consequences have been criticized on the grounds that they decrease intrinsic motivation or internally initiated behavior. Two popular rationales for this criticism, Lepper's overjustification hypothesis (1981) and Deci's motivational theory (Deci & Ryan, 1985), are reviewed and the criticism is then redefined behaviorally. "Intrinsically controlled" behavior is defined as behavior maintained by response-produced reinforcers, and the question concerning extrinsic consequences is thus restated as follows: When behavior is maintained by response-produced stimuli, does extrinsic reinforcement decrease the reinforcing value of those stimuli? The empirical support for this detrimental effect is summarized briefly, and several possible explanations for the phenomenon are offered. Research results that reflect on the effect's generality and social significance are discussed next, with the conclusion that the effect is transient and not likely to occur at all if extrinsic rewards are reinforcing, noncompetitive, based on reasonable performance standards, and delivered repetitively.

  14. Reduced responses of macrophages on nanometer surface features of altered alumina crystalline phases.

    PubMed

    Khang, Dongwoo; Liu-Snyder, Peishan; Pareta, Rajesh; Lu, Jing; Webster, Thomas J

    2009-06-01

    Extensive prolonged interactions of inflammatory cells (such as macrophages) at the host-implant interface may lead to implant failure. While previous studies have shown increased in vitro and in vivo bone cell adhesion, proliferation and mineralization on nanophase compared to currently implanted ceramics, few studies have been conducted to elucidate inflammatory cell responses on such nanophase ceramics. Controlling surface feature size and corresponding surface roughness on implants may clearly alter immune cell responses, which would be an extremely important consideration for the use of nanostructured materials as improved biomaterials. In this study, reduced macrophage density was observed on alumina (Al(2)O(3)) compacts with greater nanometer surface roughness accompanied by changes in crystallinity for up to 24 h in culture. Since alumina is a commonly used ceramic in orthopedic applications, this in vitro study continues to support the use of nanophase ceramics as improved orthopedic implants by demonstrating reduced macrophage responses.

  15. Estimation of blood perfusion using phase shift in temperature response to sinusoidal heating at the skin surface.

    PubMed

    Liu, J; Xu, L X

    1999-09-01

    A closed form analytical solution of the Pennes' bio-heat equation was obtained for temperature distributions in the skin tissue subject to the sinusoidal heat flux. Phase shifts in the surface temperature response were revealed to be related to local blood perfusion rate and heating frequency. The influence of the thermal contact resistance on the perfusion estimation was investigated. It has been proved that this influence is relatively small because of the phase shift based estimation and can be effectively eliminated by application of highly conductive grease. This analysis provides the theoretical foundation for a new noninvasive modality of blood perfusion estimation based on the surface temperature measurement which can have significant applications in future clinical practices.

  16. Interdiffusion and Intrinsic Diffusion in the Mg-Al System

    SciTech Connect

    Brennan, Sarah; Bermudez, Katrina; Sohn, Yong Ho; Kulkarni, Nagraj S

    2012-01-01

    Solid-to-solid diffusion couples were assembled and annealed to examine the diffusion between pure Mg (99.96%) and Al (99.999%). Diffusion anneals were carried out at 300 , 350 , and 400 C for 720, 360, and 240 hours, respectively. Optical and scanning electron microscopes were utilized to identify the formation of the intermetallic phases, -Al12Mg17 and -Al3Mg2 and absence of the -phase in the diffusion couples. Thicknesses of the -Al12Mg17 and -Al3Mg2 phases were measured and the parabolic growth constants were calculated to determine the activation energies for the growth, 165 and 86 KJ/mole, respectively. Concentration profiles were determined with electron microprobe analysis using pure elemental standards. Composition-dependent interdiffusion coefficients in Mg-solid solution, -Al12Mg17 and - Al3Mg2 and Al-solid solutions were calculated based on the Boltzmann-Matano analysis. Average effective interdiffusion coefficients for each phase were also calculated, and the magnitude was the highest for the -Al3Mg2 phase, followed by -Al12Mg17, Al-solid solution and Mg-solid solution. Intrinsic diffusion coefficients based on Huemann s analysis (e.g., marker plane) were determined for the ~38 at.% Mg in the -Al3Mg2 phase. Activation energies and the pre-exponential factors for the inter- and intrinsic diffusion coefficients were calculated for the temperature range examined. The -Al3Mg2 phase was found to have the lowest activation energies for growth and interdiffusion among all four phases studied. At the marker location in the -Al3Mg2 phase, the intrinsic diffusion of Al was found to be faster than that of Mg. Extrapolations of the impurity diffusion coefficients in the terminal solid solutions were made and compared to the available self- and impurity diffusion data from literature. Thermodynamic factor, tracer diffusion coefficients and atomic mobilities at the marker plane composition were approximated using available literature values of Mg activity in the -Al

  17. Separating Scattering from Intrinsic Attenuation

    NASA Astrophysics Data System (ADS)

    van Wijk, K.; Scales, J. A.

    2003-12-01

    The subsurface appears disordered at all length-scales. Therefore, wave propatation at seismic or ultrasonic frequencies is subject to complicated scatterings. A pulse propagating in the subsurface loses energy at each scattering off an impedance contrast, but also decreases in amplitude as the impulse interacts with fluids in the rock. We call the latter non-elastic effect "intrinsic Q", while the former is "scattering Q". It is often the fluids in the rocks that are of interest, but conventional reflection and transmission of the incident pulse only cannot deceipher the individual components of Q due to scattering and fluid movement in the pore-space. We present an approach that can unravel these two mechanisms, allowing a separate estimate of absorption. This method treats the propagation of the average intensity in the framework of radiative transfer (RT); the arrival of (what is left of) the incident pulse is modeled as the coherent energy, whereas the later arriving multiply scattered events form the incoherent intensity. The coherent pulse decays exponentially due to a combination of scattering and absorption, and so does the incoherent intensity. However, multiple scattering can re-direct energy back to the receiver, supplying a gain-term at later times that makes up the incoherent intensity. Strictly speaking, one can invert for scattering and absorption from the intensity at late times only, often modeled with the late-time equivalent of RT, diffusion. However, we will show that fitting both early- and late-time signal with RT constrains absorption and scattering constants more rigorously. These ideas are illustrated by laboratory and sonic-logging measurements.

  18. Activation of InsP3 receptors is sufficient for inducing graded intrinsic plasticity in rat hippocampal pyramidal neurons

    PubMed Central

    Ashhad, Sufyan; Johnston, Daniel

    2014-01-01

    The synaptic plasticity literature has focused on establishing necessity and sufficiency as two essential and distinct features in causally relating a signaling molecule to plasticity induction, an approach that has been surprisingly lacking in the intrinsic plasticity literature. In this study, we complemented the recently established necessity of inositol trisphosphate (InsP3) receptors (InsP3R) in a form of intrinsic plasticity by asking if InsP3R activation was sufficient to induce intrinsic plasticity in hippocampal neurons. Specifically, incorporation of d-myo-InsP3 in the recording pipette reduced input resistance, maximal impedance amplitude, and temporal summation but increased resonance frequency, resonance strength, sag ratio, and impedance phase lead. Strikingly, the magnitude of plasticity in all these measurements was dependent on InsP3 concentration, emphasizing the graded dependence of such plasticity on InsP3R activation. Mechanistically, we found that this InsP3-induced plasticity depended on hyperpolarization-activated cyclic nucleotide-gated channels. Moreover, this calcium-dependent form of plasticity was critically reliant on the release of calcium through InsP3Rs, the influx of calcium through N-methyl-d-aspartate receptors and voltage-gated calcium channels, and on the protein kinase A pathway. Our results delineate a causal role for InsP3Rs in graded adaptation of neuronal response dynamics, revealing novel regulatory roles for the endoplasmic reticulum in neural coding and homeostasis. PMID:25552640

  19. Intrinsic and Network Mechanisms Constrain Neural Synchrony in the Moth Antennal Lobe.

    PubMed

    Lei, Hong; Yu, Yanxue; Zhu, Shuifang; Rangan, Aaditya V

    2016-01-01

    Projection-neurons (PNs) within the antennal lobe (AL) of the hawkmoth respond vigorously to odor stimulation, with each vigorous response followed by a ~1 s period of suppression-dubbed the "afterhyperpolarization-phase," or AHP-phase. Prior evidence indicates that this AHP-phase is important for the processing of odors, but the mechanisms underlying this phase and its function remain unknown. We investigate this issue. Beginning with several physiological experiments, we find that pharmacological manipulation of the AL yields surprising results. Specifically, (a) the application of picrotoxin (PTX) lengthens the AHP-phase and reduces PN activity, whereas (b) the application of Bicuculline-methiodide (BIC) reduces the AHP-phase and increases PN activity. These results are curious, as both PTX and BIC are inhibitory-receptor antagonists. To resolve this conundrum, we speculate that perhaps (a) PTX reduces PN activity through a disinhibitory circuit involving a heterogeneous population of local-neurons, and (b) BIC acts to hamper certain intrinsic currents within the PNs that contribute to the AHP-phase. To probe these hypotheses further we build a computational model of the AL and benchmark our model against our experimental observations. We find that, for parameters which satisfy these benchmarks, our model exhibits a particular kind of synchronous activity: namely, "multiple-firing-events" (MFEs). These MFEs are causally-linked sequences of spikes which emerge stochastically, and turn out to have important dynamical consequences for all the experimentally observed phenomena we used as benchmarks. Taking a step back, we extract a few predictions from our computational model pertaining to the real AL: Some predictions deal with the MFEs we expect to see in the real AL, whereas other predictions involve the runaway synchronization that we expect when BIC-application hampers the AHP-phase. By examining the literature we see support for the former, and we perform some

  20. Intrinsic and Network Mechanisms Constrain Neural Synchrony in the Moth Antennal Lobe

    PubMed Central

    Lei, Hong; Yu, Yanxue; Zhu, Shuifang; Rangan, Aaditya V.

    2016-01-01

    Projection-neurons (PNs) within the antennal lobe (AL) of the hawkmoth respond vigorously to odor stimulation, with each vigorous response followed by a ~1 s period of suppression—dubbed the “afterhyperpolarization-phase,” or AHP-phase. Prior evidence indicates that this AHP-phase is important for the processing of odors, but the mechanisms underlying this phase and its function remain unknown. We investigate this issue. Beginning with several physiological experiments, we find that pharmacological manipulation of the AL yields surprising results. Specifically, (a) the application of picrotoxin (PTX) lengthens the AHP-phase and reduces PN activity, whereas (b) the application of Bicuculline-methiodide (BIC) reduces the AHP-phase and increases PN activity. These results are curious, as both PTX and BIC are inhibitory-receptor antagonists. To resolve this conundrum, we speculate that perhaps (a) PTX reduces PN activity through a disinhibitory circuit involving a heterogeneous population of local-neurons, and (b) BIC acts to hamper certain intrinsic currents within the PNs that contribute to the AHP-phase. To probe these hypotheses further we build a computational model of the AL and benchmark our model against our experimental observations. We find that, for parameters which satisfy these benchmarks, our model exhibits a particular kind of synchronous activity: namely, “multiple-firing-events” (MFEs). These MFEs are causally-linked sequences of spikes which emerge stochastically, and turn out to have important dynamical consequences for all the experimentally observed phenomena we used as benchmarks. Taking a step back, we extract a few predictions from our computational model pertaining to the real AL: Some predictions deal with the MFEs we expect to see in the real AL, whereas other predictions involve the runaway synchronization that we expect when BIC-application hampers the AHP-phase. By examining the literature we see support for the former, and we

  1. The restless brain: how intrinsic activity organizes brain function

    PubMed Central

    Raichle, Marcus E.

    2015-01-01

    Traditionally studies of brain function have focused on task-evoked responses. By their very nature such experiments tacitly encourage a reflexive view of brain function. While such an approach has been remarkably productive at all levels of neuroscience, it ignores the alternative possibility that brain functions are mainly intrinsic and ongoing, involving information processing for interpreting, responding to and predicting environmental demands. I suggest that the latter view best captures the essence of brain function, a position that accords well with the allocation of the brain's energy resources, its limited access to sensory information and a dynamic, intrinsic functional organization. The nature of this intrinsic activity, which exhibits a surprising level of organization with dimensions of both space and time, is revealed in the ongoing activity of the brain and its metabolism. As we look to the future, understanding the nature of this intrinsic activity will require integrating knowledge from cognitive and systems neuroscience with cellular and molecular neuroscience where ion channels, receptors, components of signal transduction and metabolic pathways are all in a constant state of flux. The reward for doing so will be a much better understanding of human behaviour in health and disease. PMID:25823869

  2. The restless brain: how intrinsic activity organizes brain function.

    PubMed

    Raichle, Marcus E

    2015-05-19

    Traditionally studies of brain function have focused on task-evoked responses. By their very nature such experiments tacitly encourage a reflexive view of brain function. While such an approach has been remarkably productive at all levels of neuroscience, it ignores the alternative possibility that brain functions are mainly intrinsic and ongoing, involving information processing for interpreting, responding to and predicting environmental demands. I suggest that the latter view best captures the essence of brain function, a position that accords well with the allocation of the brain's energy resources, its limited access to sensory information and a dynamic, intrinsic functional organization. The nature of this intrinsic activity, which exhibits a surprising level of organization with dimensions of both space and time, is revealed in the ongoing activity of the brain and its metabolism. As we look to the future, understanding the nature of this intrinsic activity will require integrating knowledge from cognitive and systems neuroscience with cellular and molecular neuroscience where ion channels, receptors, components of signal transduction and metabolic pathways are all in a constant state of flux. The reward for doing so will be a much better understanding of human behaviour in health and disease.

  3. 40 CFR 35.6570 - Use of the same engineer during subsequent phases of response.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Superfund State Contracts for Superfund Response Actions Procurement Requirements Under A Cooperative...-on services and initial procurement complied with the procurement requirements, the recipient of a... using CERCLA funds for follow-on activities, the recipient may use the engineer for subsequent...

  4. Enhancement of the acute phase response to lipopolysaccharide (LPS) challenge in steers supplemented with chromium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The study examined the effect of chromium supplementation on the response of steers to an LPS challenge. Twenty steers received a premix that added 0 (control) or 0.2 mg/kg of chromium (KemTRACE®brandChromiumProprionate 0.04%, Kemin Industries) to the total diet on a dry matter basis for 55 d. Steer...

  5. 40 CFR 35.6570 - Use of the same engineer during subsequent phases of response.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... it selected the engineer and the code of conduct requirements described in 40 CFR 31.36(b)(3). (ii... CERCLA remedial response Cooperative Agreement may use the engineer procured to conduct any or all of the... using CERCLA funds for follow-on activities, the recipient may use the engineer for subsequent...

  6. 40 CFR 35.6570 - Use of the same engineer during subsequent phases of response.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... it selected the engineer and the code of conduct requirements described in 40 CFR 31.36(b)(3). (ii... CERCLA remedial response Cooperative Agreement may use the engineer procured to conduct any or all of the... using CERCLA funds for follow-on activities, the recipient may use the engineer for subsequent...

  7. 40 CFR 35.6570 - Use of the same engineer during subsequent phases of response.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... it selected the engineer and the code of conduct requirements described in 40 CFR 31.36(b)(3). (ii... CERCLA remedial response Cooperative Agreement may use the engineer procured to conduct any or all of the... using CERCLA funds for follow-on activities, the recipient may use the engineer for subsequent...

  8. Chromium supplementation enhances the acute phase response of steers to a lipopolysaccharide (LPS) challenge

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The study examined the effect of chromium supplementation on the response of steers to an LPS challenge. Twenty crossbred steers (235±4 kg BW) received 0 ppb (Control; C) or 200 ppb chromium propionate (CHR) for 55 days. Steers were fitted with jugular catheters and rectal temperature (RT) recording...

  9. Seismic Safety Margins Research Program. Phase I, final report. Major structure response (Project IV). Volume 5

    SciTech Connect

    Benda, B. J.; Johnson, J. J.; Lo, T. Y.

    1981-05-01

    Task of the Major Structure Response Project within the Seismic Safety Margins Research Program (SSMRP) was to develop detailed finite element models of the Zion Nuclear Power Plant's containment building and auxiliary-fuel-turbine (AFT) complex. The resulting models served as input to the seismic methodology analysis chain.

  10. Phase transformations, microstructure formation and in vitro osteoblast response in calcium silicate/brushite cement composites.

    PubMed

    Sopcak, T; Medvecky, L; Giretova, M; Kovalcikova, A; Stulajterova, R; Durisin, J

    2016-01-01

    Self-setting simple calcium silicate/brushite (B) biocements with various Ca/P ratios were prepared by mutual mixing of both monocalcium silicate hydrate (CSH) or β-wollastonite (woll) powders with B and the addition of 2 wt% NaH2PO4 solution as a hardening liquid. The phase composition of the final composites and the texture of the surface calcium phosphate/silica layer were controlled by the starting Ca/P ratio in composites and the pH during setting. It was verified that the presence of continuous bone-like calcium phosphate coating on the surface of the samples was not essential for in vitro osteoblast proliferation. The nanocrystalline calcium deficient hydroxyapatite and amorphous silica were found as the main setting products in composite mixtures with a Ca/P ratio close to the region of the formation of deficient hydroxyapatite-like calcium phosphates. No CSH phase with a lower Ca/Si ratio was identified after transformation. The results confirmed a small effect of the monocalcium silicate addition on the compressive strength (CS) of cements up to 30 wt% (around 20-25 MPa) and a significant rise of the value in 50 woll/B cement (65 MPa). The final setting times of the cement composites varied between 5 and 43 min depending on the P/L ratio and the type of monocalcium silicate phase in the cement mixture. 10CSH/B and 50 woll/B cements with different textures but free of both the needle-like and perpendicularly-oriented hydroxyapatite particles on the surface of the samples had low cytotoxicity. PMID:27509265

  11. Stroke phases responses around maximal lactate steady state in front crawl.

    PubMed

    Pelarigo, Jailton G; Denadai, Benedito S; Greco, Camila C

    2011-03-01

    The objective of this study was to analyze changes in stroke rate (SR), stroke length (SL) and stroke phases (entry and catch, pull, push and recovery) when swimming at (MLSS) and above (102.5% MLSS) the maximal lactate steady state. Twelve endurance swimmers (21±8 year, 1.77±0.10 m and 71.6±7.7 kg) performed in different days the following tests: (1) 200- and 400-m all-out tests, to determine critical speed (CS), and; (2) 2-4 30-min sub-maximal constant-speed tests, to determine the MLSS and 102.5% MLSS. There was significant difference among MLSS (1.22±0.05 ms(-1)), 102.5% MLSS (1.25±0.04 ms(-1)) and CS (1.30±0.08 ms(-1)). SR and SL were maintained between the 10th and 30th minute of the test swum at MLSS and have modified significantly at 102.5% MLSS (SR - 30.9±3.4 and 32.2±3.5 cycles min(-1) and SL - 2.47±0.2 and 2.38±0.2 m cycle(-1), respectively). All stroke phases were maintained at 10th and 30th minute at MLSS. However, the relative duration of propulsive phase B (pull) increased significantly at 102.5% MLSS (21.7±3.4% and 22.9±3.9%, respectively). Therefore, the metabolic condition may influence the stroke parameters (SR and SL) and stroke strategy to maintain the speed during swim tests lasting 30 min.

  12. Broadband diffuse reflections of sound by metasurface with random phase response

    NASA Astrophysics Data System (ADS)

    Gu, Zhong-ming; Liang, Bin; Zou, Xin-ye; Cheng, Jian-chun

    2015-09-01

    We have designed an ultrathin planar structure capable of generating diffuse reflections within a broadband. By introducing randomly distributed gradients along the interface, the proposed structure can scatter the incident acoustic waves into all directions and virtually suppress the scattered lobes that will otherwise be remarkable for a planar surface. A practical implementation by labryinthine-like metamaterial with designed phase shift profile is demontrated. The numerical results show that our designed planar surface could be used to mimic a rugged surface as expected. We envision our designed structure to exhibit potentials in applications such as room acoustics and acoustic stealth.

  13. Change in the plasmid copy number in acetic acid bacteria in response to growth phase and acetic acid concentration.

    PubMed

    Akasaka, Naoki; Astuti, Wiwik; Ishii, Yuri; Hidese, Ryota; Sakoda, Hisao; Fujiwara, Shinsuke

    2015-06-01

    Plasmids pGE1 (2.5 kb), pGE2 (7.2 kb), and pGE3 (5.5 kb) were isolated from Gluconacetobacter europaeus KGMA0119, and sequence analyses revealed they harbored 3, 8, and 4 genes, respectively. Plasmid copy numbers (PCNs) were determined by real-time quantitative PCR at different stages of bacterial growth. When KGMA0119 was cultured in medium containing 0.4% ethanol and 0.5% acetic acid, PCN of pGE1 increased from 7 copies/genome in the logarithmic phase to a maximum of 12 copies/genome at the beginning of the stationary phase, before decreasing to 4 copies/genome in the late stationary phase. PCNs for pGE2 and pGE3 were maintained at 1-3 copies/genome during all phases of growth. Under a higher concentration of ethanol (3.2%) the PCN for pGE1 was slightly lower in all the growth stages, and those of pGE2 and pGE3 were unchanged. In the presence of 1.0% acetic acid, PCNs were higher for pGE1 (10 copies/genome) and pGE3 (6 copies/genome) during the logarithmic phase. Numbers for pGE2 did not change, indicating that pGE1 and pGE3 increase their PCNs in response to acetic acid. Plasmids pBE2 and pBE3 were constructed by ligating linearized pGE2 and pGE3 into pBR322. Both plasmids were replicable in Escherichia coli, Acetobacter pasteurianus and G. europaeus, highlighting their suitability as vectors for acetic acid bacteria.

  14. Change in the plasmid copy number in acetic acid bacteria in response to growth phase and acetic acid concentration.

    PubMed

    Akasaka, Naoki; Astuti, Wiwik; Ishii, Yuri; Hidese, Ryota; Sakoda, Hisao; Fujiwara, Shinsuke

    2015-06-01

    Plasmids pGE1 (2.5 kb), pGE2 (7.2 kb), and pGE3 (5.5 kb) were isolated from Gluconacetobacter europaeus KGMA0119, and sequence analyses revealed they harbored 3, 8, and 4 genes, respectively. Plasmid copy numbers (PCNs) were determined by real-time quantitative PCR at different stages of bacterial growth. When KGMA0119 was cultured in medium containing 0.4% ethanol and 0.5% acetic acid, PCN of pGE1 increased from 7 copies/genome in the logarithmic phase to a maximum of 12 copies/genome at the beginning of the stationary phase, before decreasing to 4 copies/genome in the late stationary phase. PCNs for pGE2 and pGE3 were maintained at 1-3 copies/genome during all phases of growth. Under a higher concentration of ethanol (3.2%) the PCN for pGE1 was slightly lower in all the growth stages, and those of pGE2 and pGE3 were unchanged. In the presence of 1.0% acetic acid, PCNs were higher for pGE1 (10 copies/genome) and pGE3 (6 copies/genome) during the logarithmic phase. Numbers for pGE2 did not change, indicating that pGE1 and pGE3 increase their PCNs in response to acetic acid. Plasmids pBE2 and pBE3 were constructed by ligating linearized pGE2 and pGE3 into pBR322. Both plasmids were replicable in Escherichia coli, Acetobacter pasteurianus and G. europaeus, highlighting their suitability as vectors for acetic acid bacteria. PMID:25575969

  15. The Juvenile Phase of Maize Sees Upregulation of Stress-Response Genes and Is Extended by Exogenous Jasmonic Acid.

    PubMed

    Beydler, Benjamin; Osadchuk, Krista; Cheng, Chi-Lien; Manak, J Robert; Irish, Erin E

    2016-08-01

    As maize (Zea mays) plants undergo vegetative phase change from juvenile to adult, they both exhibit heteroblasty, an abrupt change in patterns of leaf morphogenesis, and gain the ability to produce flowers. Both processes are under the control of microRNA156 (miR156), whose levels decline at the end of the juvenile phase. Gain of the ability to flower is conferred by the expression of miR156 targets that encode SQUAMOSA PROMOTER-BINDING transcription factors, which, when derepressed in the adult phase, induce the expression of MADS box transcription factors that promote maturation and flowering. How gene expression, including targets of those microRNAs, differs between the two phases remains an open question. Here, we compare transcript levels in primordia that will develop into juvenile or adult leaves to identify genes that define these two developmental states and may influence vegetative phase change. In comparisons among successive leaves at the same developmental stage, plastochron 6, three-fourths of approximately 1,100 differentially expressed genes were more highly expressed in primordia of juvenile leaves. This juvenile set was enriched in photosynthetic genes, particularly those associated with cyclic electron flow at photosystem I, and in genes involved in oxidative stress and retrograde redox signaling. Pathogen- and herbivory-responsive pathways including salicylic acid and jasmonic acid also were up-regulated in juvenile primordia; indeed, exogenous application of jasmonic acid delayed both the appearance of adult traits and the decline in the expression of miR156-encoding loci in maize seedlings. We hypothesize that the stresses associated with germination promote juvenile patterns of differentiation in maize. PMID:27307257

  16. Transport of Intrinsic Plutonium Colloids in Saturated Porous Media

    NASA Astrophysics Data System (ADS)

    Zhou, D.; Abdel-Fattah, A.; Boukhalfa, H.; Ware, S. D.; Tarimala, S.; Keller, A. A.

    2011-12-01

    Actinide contaminants were introduced to the subsurface environment as a result of nuclear weapons development and testing, as well as for nuclear power generation and related research activities for defense and civilian applications. Even though most actinide species were believed to be fairly immobile once in the subsurface, recent studies have shown the transport of actinides kilometers away from their disposal sites. For example, the treated liquid wastes released into Mortandad Canyon at the Los Alamos National Laboratory were predicted to travel less than a few meters; however, plutonium and americium have been detected 3.4 km away from the waste outfall. A colloid-facilitated mechanism has been suggested to account for this unexpected transport of these radioactive wastes. Clays, oxides, organic matters, and actinide hydroxides have all been proposed as the possible mobile phase. Pu ions associated with natural colloids are often referred to as pseudo-Pu colloids, in contrast with the intrinsic Pu colloids that consist of Pu oxides. Significant efforts have been made to investigate the role of pseudo-Pu colloids, while few studies have evaluated the environmental behavior of the intrinsic Pu colloids. Given the fact that Pu (IV) has extremely low solubility product constant, it can be inferred that the transport of Pu in the intrinsic form is highly likely at suitable environmental conditions. This study investigates the transport of intrinsic Pu colloids in a saturated alluvium material packed in a cylindrical column (2.5-cm Dia. x 30-cm high) and compares the results to previous data on the transport of pseudo Pu colloids in the same material. A procedure to prepare a stable intrinsic Pu colloid suspension that produced consistent and reproducible electrokinetic and stability data was developed. Electrokinetic properties and aggregation stability were characterized. The Pu colloids, together with trillium as a conservative tracer, were injected into the

  17. Phase Transition of a Disordered Nuage Protein Generates Environmentally Responsive Membraneless Organelles

    PubMed Central

    Nott, Timothy J.; Petsalaki, Evangelia; Farber, Patrick; Jervis, Dylan; Fussner, Eden; Plochowietz, Anne; Craggs, Timothy D.; Bazett-Jones, David P.; Pawson, Tony; Forman-Kay, Julie D.; Baldwin, Andrew J.

    2015-01-01

    Summary Cells chemically isolate molecules in compartments to both facilitate and regulate their interactions. In addition to membrane-encapsulated compartments, cells can form proteinaceous and membraneless organelles, including nucleoli, Cajal and PML bodies, and stress granules. The principles that determine when and why these structures form have remained elusive. Here, we demonstrate that the disordered tails of Ddx4, a primary constituent of nuage or germ granules, form phase-separated organelles both in live cells and in vitro. These bodies are stabilized by patterned electrostatic interactions that are highly sensitive to temperature, ionic strength, arginine methylation, and splicing. Sequence determinants are used to identify proteins found in both membraneless organelles and cell adhesion. Moreover, the bodies provide an alternative solvent environment that can concentrate single-stranded DNA but largely exclude double-stranded DNA. We propose that phase separation of disordered proteins containing weakly interacting blocks is a general mechanism for forming regulated, membraneless organelles. PMID:25747659

  18. Shock Response and Phase Transitions of MgO at Planetary Impact Conditions.

    PubMed

    Root, Seth; Shulenburger, Luke; Lemke, Raymond W; Dolan, Daniel H; Mattsson, Thomas R; Desjarlais, Michael P

    2015-11-01

    The moon-forming impact and the subsequent evolution of the proto-Earth is strongly dependent on the properties of materials at the extreme conditions generated by this violent collision. We examine the high pressure behavior of MgO, one of the dominant constituents in Earth's mantle, using high-precision, plate impact shock compression experiments performed on Sandia National Laboratories' Z Machine and extensive quantum calculations using density functional theory (DFT) and quantum Monte Carlo (QMC) methods. The combined data span from ambient conditions to 1.2 TPa and 42 000 K, showing solid-solid and solid-liquid phase boundaries. Furthermore our results indicate that under impact the solid and liquid phases coexist for more than 100 GPa, pushing complete melting to pressures in excess of 600 GPa. The high pressure required for complete shock melting has implications for a broad range of planetary collision events. PMID:26588422

  19. Clinical Practice Guideline for the Treatment of Intrinsic Circadian Rhythm Sleep-Wake Disorders: Advanced Sleep-Wake Phase Disorder (ASWPD), Delayed Sleep-Wake Phase Disorder (DSWPD), Non-24-Hour Sleep-Wake Rhythm Disorder (N24SWD), and Irregular Sleep-Wake Rhythm Disorder (ISWRD). An Update for 2015: An American Academy of Sleep Medicine Clinical Practice Guideline.

    PubMed

    Auger, R Robert; Burgess, Helen J; Emens, Jonathan S; Deriy, Ludmila V; Thomas, Sherene M; Sharkey, Katherine M

    2015-10-01

    A systematic literature review and meta-analyses (where appropriate) were performed and the GRADE approach was used to update the previous American Academy of Sleep Medicine Practice Parameters on the treatment of intrinsic circadian rhythm sleep-wake disorders. Available data allowed for positive endorsement (at a second-tier degree of confidence) of strategically timed melatonin (for the treatment of DSWPD, blind adults with N24SWD, and children/ adolescents with ISWRD and comorbid neurological disorders), and light therapy with or without accompanying behavioral interventions (adults with ASWPD, children/adolescents with DSWPD, and elderly with dementia). Recommendations against the use of melatonin and discrete sleep-promoting medications are provided for demented elderly patients, at a second- and first-tier degree of confidence, respectively. No recommendations were provided for remaining treatments/ populations, due to either insufficient or absent data. Areas where further research is needed are discussed.

  20. Exact Calculation of Hydrodynamical Response Functions during the Deconfinement Phase Transition from a Hadronic Gas to a Colorless QGP

    SciTech Connect

    Ladrem, M.; Zaki-Al-Full, Z.

    2011-05-23

    In our previous work we have performed an exact calculation using the colorless partition function of the QGP by probing the behavior of some useful thermodynamic response functions on the whole range of temperature. If the system formed in an ultra relativistic heavy ion collision reaches a state of local thermodynamic equilibrium and if it can be locally maintained during the subsequent expansion, the further evolution of the QGP and Hadronic Gas can be described conveniently by Relativistic Hydrodynamics. It requires knowledge of the equation of state, which gives a relation between pressure P, energy density {epsilon}, entropy density s and sound velocity c{sub s}. Precisely, in the present work we have performed the study of these hydrodynamical response functions, outshining the physics of the evolution of the system undergoing a deconfinement phase transition, when the colorless condition is taken into account.

  1. Theoretical exploration of Josephson Plasma Emission in Intrinsic Josephson Junctions

    SciTech Connect

    Tachiki, M.; Machida, M.

    2000-07-18

    In this paper, the authors theoretically predict the best efficient way for electromagnetic wave emission by Josephson plasma excitation in intrinsic Josephson junctions. First, they briefly derive basic equations describing dynamics of phase differences inside junction sites in intrinsic Josephson junctions, and review the nature of Josephson plasma excitation modes based on the equations. Especially, they make an attention to that Josephson plasma modes have much different dispersion relations depending on the propagating directions and their different modes can be recognized as N standing waves propagating along ah-plane in cases of finite stacked systems composed of N junctions. Second, they consider how to excite their modes and point out that excitations of in-phase mode with the highest propagation velocity among their N modes are the most efficient way for electromagnetic wave emissions. Finally, they clarify that in-phase excitations over all junctions are possible by using Josephson vortex flow states. They show simulation results of Josephson vortex flow states resonating with some Josephson plasma modes and predict that superradiance of electromagnetic field may occur in rectangular vortex flow state in which spatiotemporal oscillations of electromagnetic fields are perfectly in-phase.

  2. Protein-energy malnutrition induces an aberrant acute-phase response and modifies the circadian rhythm of core temperature.

    PubMed

    Smith, Shari E; Ramos, Rafaela Andrade; Refinetti, Roberto; Farthing, Jonathan P; Paterson, Phyllis G

    2013-08-01

    Protein-energy malnutrition (PEM), present in 12%-19% of stroke patients upon hospital admission, appears to be a detrimental comorbidity factor that impairs functional outcome, but the mechanisms are not fully elucidated. Because ischemic brain injury is highly temperature-sensitive, the objectives of this study were to investigate whether PEM causes sustained changes in temperature that are associated with an inflammatory response. Activity levels were recorded as a possible explanation for the immediate elevation in temperature upon introduction to a low protein diet. Male, Sprague-Dawley rats (7 weeks old) were fed a control diet (18% protein) or a low protein diet (PEM, 2% protein) for either 7 or 28 days. Continuous core temperature recordings from bioelectrical sensor transmitters demonstrated a rapid increase in temperature amplitude, sustained over 28 days, in response to a low protein diet. Daily mean temperature rose transiently by day 2 (p = 0.01), falling to normal by day 4 (p = 0.08), after which mean temperature continually declined as malnutrition progressed. There were no alterations in activity mean (p = 0.3) or amplitude (p = 0.2) that were associated with the early rise in mean temperature. Increased serum alpha-2-macroglobulin (p < 0.001) and decreased serum albumin (p ≤ 0.005) combined with a decrease in serum alpha-1-acid glycoprotein (p < 0.001) suggest an atypical acute-phase response. In contrast, a low protein diet had no effect on the signaling pathway of the pro-inflammatory transcription factor, NFκB, in the hippocampus. In conclusion, PEM induces an aberrant and sustained acute-phase response coupled with long-lasting effects on body temperature.

  3. Metabolic Cost of the Activation of Immune Response in the Fish-Eating Myotis (Myotis vivesi): The Effects of Inflammation and the Acute Phase Response

    PubMed Central

    Otálora-Ardila, Aída; Herrera M., L. Gerardo; Flores-Martínez, José Juan; Welch, Kenneth C.

    2016-01-01

    Inflammation and activation of the acute phase response (APR) are energetically demanding processes that protect against pathogens. Phytohaemagglutinin (PHA) and lipopolysaccharide (LPS) are antigens commonly used to stimulate inflammation and the APR, respectively. We tested the hypothesis that the APR after an LPS challenge was energetically more costly than the inflammatory response after a PHA challenge in the fish-eating Myotis bat (Myotis vivesi). We measured resting metabolic rate (RMR) after bats were administered PHA and LPS. We also measured skin temperature (Tskin) after the LPS challenge and skin swelling after the PHA challenge. Injection of PHA elicited swelling that lasted for several days but changes in RMR and body mass were not significant. LPS injection produced a significant increase in Tskin and in RMR, and significant body mass loss. RMR after LPS injection increased by 140–185% and the total cost of the response was 6.50 kJ. Inflammation was an energetically low-cost process but the APR entailed a significant energetic investment. Examination of APR in other bats suggests that the way in which bats deal with infections might not be uniform. PMID:27792729

  4. Enhanced spectral response of π-phase shifted fiber Bragg gratings in closed-loop configuration.

    PubMed

    Malara, P; Campanella, C E; De Leonardis, F; Giorgini, A; Avino, S; Passaro, V M N; Gagliardi, G

    2015-05-01

    The transmission spectrum of a ring resonator enclosing a π-phase shifted fiber Bragg grating (π-FBG) shows a spectral feature at the Bragg wavelength that is much sharper than resonance of the π-FBG alone, and that can be detected with a simple integrated cavity output technique. Hence, the resolution of any sensor based on the fitting of the π-FBG spectral profile can be largely improved by the proposed configuration at no additional fabrication costs and without altering the sensor robustness. A theoretical model shows that the resolution enhancement attainable in the proposed closed-loop geometry depends on the quality factor of the ring resonator. With a commercial grating in a medium-finesse ring, a spectral feature 12 times sharper than the π-FBG resonance is experimentally demonstrated. A larger enhancement is expected in a low-loss, polarization maintaining setup. PMID:25927801

  5. Preparation and phase transition behaviors of temperature-responsive 3-butoxy-2-hydroxypropyl hydroxyethyl celluloses.

    PubMed

    Tian, Ye; Ju, Benzhi; Zhang, Shufen; Duan, Xiuling; Dong, Daopeng

    2015-01-01

    2-Hydroxy-3-butoxypropyl hydroxyethyl celluloses (HBPEC), which are thermoresponsive polymers, are prepared by grafting butyl glycidyl ether onto hydroxyethyl cellulose. The effects of several factors on the cloud point (Tc) of the HBPEC are also investigated. The Tc of HBPEC can be tuned to a ranging from 17.0 to 43.0 °C by changing the molar substitution of hydrophobic groups. Increasing the concentration of HBPEC leads to a faster phase transition as well as a corresponding linear decrease in the Tc. A series of salts with common anions or cations are used to investigate the effects of specific anions or cations on the Tc of HBPEC aqueous solutions. It is discovered that the Tc of HBPEC is largely influenced by the variation of cation identity and concentration. Plotting Tc as a function of cation activity shows that the Tc can be classified by charge density. PMID:26230225

  6. Synchrony during acoustic interactions in the bushcricket Mecopoda 'Chirper' (Tettigoniidae:Orthoptera) is generated by a combination of chirp-by-chirp resetting and change in intrinsic chirp rate.

    PubMed

    Nityananda, Vivek; Balakrishnan, Rohini

    2007-01-01

    In several bushcricket species, individual males synchronise their chirps during acoustic interactions. Synchrony is imperfect with the chirps of one male leading or lagging the other by a few milliseconds. Imperfect synchrony is believed to have evolved in response to female preferences for leading chirps. We investigated the mechanism underlying synchrony in the bushcricket species Mecopoda 'Chirper' from Southern India using playback experiments and simulations of pairwise interactions. We also investigated whether intrinsic chirp period is a good predictor of leading probability during interactions between males. The mechanism underlying synchrony in this species differs from previously reported mechanisms in that it involves both a change in the oscillator's intrinsic rate and resetting on a chirp-by-chirp basis. The form of the phase response curve differs from those of previously reported firefly and bushcricket species including the closely related Malaysian species Mecopoda elongata. Simulations exploring oscillator properties showed that the outcome of pairwise interactions was independent of initial phase and alternation was not possible. Solo intrinsic chirp period was a relatively good predictor of leading probability. However, changing the intrinsic period during interactions could enable males with longer periods to lead during acoustic interactions. PMID:16983544

  7. Mars plasma system response to ICME transients at different phases of the solar cycle

    NASA Astrophysics Data System (ADS)

    Sanchez-Cano, Beatriz; Lester, Mark; Hall, Benjamin E. S.; Witasse, Olivier; Mays, M. Leila; Blelly, Pierre-Louis; Andrews, David G.; Cartacci, Marco; Opgenoorth, Hermann; Milan, Stephen E.; Ambrosi, Richard M.; Odstrcil, Dusan; Plaut, Jeffrey J.; Imber, Suzanne

    2016-10-01

    We assess the reaction of the full Martian plasma system after the impact of different Interplanetary Coronal Mass Ejections (ICME) at Mars at different levels of solar activity and phases of the solar cycle 23/24. The Mars' plasma system behaviour is characterised from the surface of the planet to the bow shock position, which is the most external boundary where the solar wind directly interacts with the Martian system. Events at the extreme phases of the solar cycle will be given special attention, i.e. low and high solar activity periods, since variations in the maximum of the thermal pressure of the ionosphere are a key factor in order to create a significant/weak plasma obstacle to compete with the solar wind. The strength of this obstacle is ultimately controlled by the long-term EUV flux modulations. Likewise, the effect of such ICMEs on the plasma boundaries and induced magnetic fields within the ionosphere will be analysed in detail. The study uses data from TIMED, GOES and STEREOs observatories at 1 AU to monitor the solar irradiance and the propagation of such space weather transits. At Mars, long-term data come from Mars Express and Mars Odyssey missions since both spacecraft have been working from more than 12 years. The MAVEN and MSL missions provide supplementary data. Solar wind propagation modelling is used through the WSA-ENLIL+Cone model, as well as several numerical simulations of the ionosphere of Mars for such scenarios are made through the numerical/fluid TRANSMARS model.

  8. The polar phase response property of monopolar ECG voltages using a Computer-Aided Design and Drafting (CAD)-based data acquisition system.

    PubMed

    Goswami, B; Mitra, M; Nag, B; Mitra, T K

    1993-11-01

    The present paper discusses a Computer-Aided Design and Drafting (CAD) based data acquisition and polar phase response study of the ECG. The scalar ECG does not show vector properties although such properties are embedded in it. In the present paper the polar phase response property of monopolar chest lead (V1 to V6) ECG voltages has been studied. A software tool has been used to evaluate the relative phase response of ECG voltages. The data acquisition of monopolar ECG records of chest leads V1 to V6 from the chart recorder has been done with the help of the AutoCAD application package. The spin harmonic constituents of ECG voltages are evaluated at each harmonic plane and the polar phase responses are studied at each plane. Some interesting results have been observed in some typical cases which are discussed in the paper. PMID:8307653

  9. Effects of time of day, gender, and menstrual cycle phase on the human response to a water load.

    PubMed

    Claybaugh, J R; Sato, A K; Crosswhite, L K; Hassell, L H

    2000-09-01

    Estrogen and progesterone interference with renal actions of arginine vasopressin (AVP) has been shown. Thus we hypothesized that women will have a higher water turnover than men and that the greatest difference will be during the luteal phase of the menstrual cycle. Seven men (32 +/- 3 yr) and six women (33 +/- 2 yr) drank 12 ml water/kg lean body mass on different days at 0800 and at 2000 following 10 h of fast and a standardized meal at 0600 and 1800. Women participated on days 4-11 and 19-25 of the menstrual cycle. Initial urine and plasma osmolalities and urine flow rates were similar in all experiments. The cumulative urine voided over 3 h following the morning drink was less in men (73 +/- 12% of the water load) compared with women in either the follicular (100 +/- 3%) or luteal phases (102 +/- 10%) of the menstrual cycle. Nighttime values (30-43% of the water load) were lower in all experiments and were not different between sexes or menstrual cycle phases. Plasma AVP was higher at night and may contribute to this diurnal response. The data are generally consistent with the stated hypothesis; however, possibly owing to the greatly reduced urine flow in both sexes at night, a difference between sexes was not observed at that time.

  10. Non-Markovian response of ultrafast coherent electronic ring currents in chiral aromatic molecules in a condensed phase

    SciTech Connect

    Mineo, H.; Lin, S. H.; Fujimura, Y.; Xu, J.; Xu, R. X.; Yan, Y. J.

    2013-12-07

    Results of a theoretical study on non-Markov response for femtosecond laser-driven coherent ring currents in chiral aromatic molecules embedded in a condensed phase are presented. Coherent ring currents are generated by coherent excitation of a pair of quasi-degenerated π-electronic excited states. The coherent electronic dynamical behaviors are strongly influenced by interactions between the electronic system and phonon bath in a condensed phase. Here, the bath correlation time is not instantaneous but should be taken to be a finite time in ultrashort time-resolved experiments. In such a case, Markov approximation breaks down. A hierarchical master equation approach for an improved semiclassical Drude dissipation model was adopted to examine the non-Markov effects on ultrafast coherent electronic ring currents of (P)-2,2{sup ′}-biphenol in a condensed phase. Time evolution of the coherent ring current derived in the hierarchical master equation approach was calculated and compared with those in the Drude model in the Markov approximation and in the static limit. The results show how non-Markovian behaviors in quantum beat signals of ring currents depend on the Drude bath damping constant. Effects of temperatures on ultrafast coherent electronic ring currents are also clarified.

  11. Vitamin B12 enhances the phase-response of circadian melatonin rhythm to a single bright light exposure in humans.

    PubMed

    Hashimoto, S; Kohsaka, M; Morita, N; Fukuda, N; Honma, S; Honma, K

    1996-12-13

    Eight young males were subjected to a single blind cross-over test to see the effects of vitamin B12 (methylcobalamin; VB12) on the phase-response of the circadian melatonin rhythm to a single bright light exposure. VB12 (0.5 mg/day) or vehicle was injected intravenously at 1230 h for 11 days, which was followed by oral administration (2 mg x 3/day) for 7 days. A serial blood sampling was performed under dim light condition (less than 200 lx) and plasma melatonin rhythm was determined before and after a single bright light exposure (2500 lx for 3 h) at 0700 h. The melatonin rhythm before the light exposure showed a smaller amplitude in the VB12 trial than in the placebo. The light exposure phase-advanced the melatonin rhythm significantly in the VB12 trail, but not in the placebo. These findings indicate that VB12 enhances the light-induced phase-shift in the human circadian rhythm. PMID:8981490

  12. Non-Markovian response of ultrafast coherent electronic ring currents in chiral aromatic molecules in a condensed phase

    NASA Astrophysics Data System (ADS)

    Mineo, H.; Lin, S. H.; Fujimura, Y.; Xu, J.; Xu, R. X.; Yan, Y. J.

    2013-12-01

    Results of a theoretical study on non-Markov response for femtosecond laser-driven coherent ring currents in chiral aromatic molecules embedded in a condensed phase are presented. Coherent ring currents are generated by coherent excitation of a pair of quasi-degenerated π-electronic excited states. The coherent electronic dynamical behaviors are strongly influenced by interactions between the electronic system and phonon bath in a condensed phase. Here, the bath correlation time is not instantaneous but should be taken to be a finite time in ultrashort time-resolved experiments. In such a case, Markov approximation breaks down. A hierarchical master equation approach for an improved semiclassical Drude dissipation model was adopted to examine the non-Markov effects on ultrafast coherent electronic ring currents of (P)-2,2'-biphenol in a condensed phase. Time evolution of the coherent ring current derived in the hierarchical master equation approach was calculated and compared with those in the Drude model in the Markov approximation and in the static limit. The results show how non-Markovian behaviors in quantum beat signals of ring currents depend on the Drude bath damping constant. Effects of temperatures on ultrafast coherent electronic ring currents are also clarified.

  13. Real-time monitoring of thermal and mechanical tissue response to modulated phased-array HIFU beams in vivo

    NASA Astrophysics Data System (ADS)

    Liu, Dalong; Ballard, John R.; Haritonova, Alyona; Choi, Jeungwan; Bischof, John; Ebbini, Emad S.

    2012-10-01

    An integrated system employing real-time ultrasound thermography and strain imaging in monitoring tissue response to phased-array heating patterns has been developed. The imaging system is implemented on a commercially available scanner (SonixRP) at frame rates > 500 fps with limited frame sizes covering the vicinity of the HIFU focal spot. These frame rates are sufficient to capture tissue motion and deformation even in the vicinity of large arteries. With the high temporal and spatial resolution of our strain imaging system, we are able to capture and separate tissue strains due to natural motion (breathing and pulsation) from HIFU induced strains (thermal and mechanical). We have collected in vivo strain imaging during sub-therapeutic and therapeutic HIFU exposure in swine and rat model. A 3.5-MHz phased array was used to generate sinusoidally-modulated pHIFU beams at different intensity levels and durations near blood vessels of different sizes (e.g. femoral in the swine and rat models). The results show that our approach is capable of characterizing the thermal and mechanical tissue response to sub-therapeutic pHIFU beam. For therapeutic pHIFU beams, the approach is still capable of localizing the therapeutic beam, but the results at the focal spot are complicated by bubble generation.

  14. Expression of complement and pentraxin proteins in acute phase response elicited by tumor photodynamic therapy: the engagement of adrenal hormones.

    PubMed

    Merchant, Soroush; Huang, Naiyan; Korbelik, Mladen

    2010-12-01

    Treatment of solid tumors by photodynamic therapy (PDT) was recently shown to trigger a strong acute phase response. Using the mouse Lewis lung carcinoma (LLC) model, the present study examined complement and pentraxin proteins as PDT-induced acute phase reactants. The results show a distinct pattern of changes in the expression of genes encoding these proteins in the tumor, as well as host liver and spleen, following PDT mediated by photosensitizer Photofrin™. These changes were influenced by glucocorticoid hormones, as evidenced by transcriptional activation of glucocorticoid receptor and the upregulation of gene encoding this receptor. The expression of gene for glucocorticoid-induced zipper (GILZ) protein, whose activity is particularly susceptible to glucocorticoid regulation, was also changed in PDT-treated tumors. A direct demonstration that tumor PDT induces glucocorticoid hormone upregulation is provided by documenting elevated levels of serum corticosterone in mice bearing PDT-treated LLC tumors. Tumor response to PDT was negatively affected by blocking glucocorticoid receptor activity, which suggests that glucocorticoid hormones have a positive impact on the therapeutic outcome with this therapy.

  15. The choice of test in phase II cancer trials assessing continuous tumour shrinkage when complete responses are expected

    PubMed Central

    Mander, Adrian P

    2015-01-01

    Traditionally, phase II cancer trials test a binary endpoint formed from a dichotomisation of the continuous change in tumour size. Directly testing the continuous endpoint provides considerable gains in power, although also results in several statistical issues. One such issue is when complete responses, i.e. complete tumour removal, are observed in multiple patients; this is a problem when normality is assumed. Using simulated data and a recently published phase II trial, we investigate how the choice of test affects the operating characteristics of the trial. We propose using parametric tests based on the censored normal distribution, comparing them to the t-test and Wilcoxon non-parametric test. The censored normal distribution fits the real dataset well, but simulations indicate its type-I error rate is inflated, and its power is only slightly higher than the t-test. The Wilcoxon test has deflated type I error. For two-arm designs, the differences are much smaller. We conclude that the t-test is suitable for use when complete responses are present, although positively skewed data can result in the non-parametric test having higher power. PMID:22179821

  16. Phase advance is an actimetric correlate of antidepressant response to sleep deprivation and light therapy in bipolar depression.

    PubMed

    Benedetti, Francesco; Dallaspezia, Sara; Fulgosi, Mara Cigala; Barbini, Barbara; Colombo, Cristina; Smeraldi, Enrico

    2007-01-01

    The combination of total sleep deprivation (TSD) and light therapy (LT) in bipolar depression causes rapid antidepressant effects, and its mechanism of action has been hypothesized to involve the enhancement of all of the monoaminergic systems targeted by antidepressant drugs (serotonin, dopamine, norepinephrine). It is still unknown if the clinical effects are paralleled by changes in biological rhythms. In a before/after design of a study of biological correlates of response, 39 inpatients affected by Type I Bipolar Disorder whose current depressive episode was without psychotic features were treated for one week with repeated TSD combined with morning LT. Wrist actigraphy was recorded throughout the study. Two-thirds of the patients responded to treatment (50% reduction in Hamilton Depression score). Responders showed an increase in daytime activity, phase-advance of the activity-rest rhythm of 57 min compared to the pre-treatment baseline, and reduced nighttime sleep. Non-responders did not show significant changes in the parameters of their activity-rest rhythm. Phase advance of the activity-rest rhythm is an actimetric correlate of the antidepressant response to TSD and LT in bipolar depression. Results are consistent with the known effects of sleep-wake manipulations and neurotransmitter function on the suprachiasmatic nucleus.

  17. Spin Hall and spin Nernst effects due to intrinsic spin-orbit coupling in monolayer and bilayer graphene.

    PubMed

    Dyrdał, Anna; Barnaś, Józef

    2012-12-01

    We consider intrinsic contributions to the spin Hall and spin Nernst effects in monolayer and bilayer graphene. The spin Hall (Nernst) effect consists in the generation of transverse spin current by longitudinal electric field (temperature gradient). The relevant electronic spectrum for monolayer and bilayer graphene has been obtained from the corresponding effective Hamiltonians. Both spin Hall and spin Nernst conductivities have been determined within the linear response theory and Green function formalism. The influence of an external vertical voltage between the two atomic sheets in the case of a bilayer graphene is also analyzed and discussed. This voltage can generally lead to a phase transition between the topological insulator phase and conventional insulator. In the case of bilayer graphene, the main focuss is on an asymmetrical case, with different spin-orbit parameters in the two atomic sheets. Such a difference may be generated by different atomic planes adjacent to bilayer graphene on its both sides.

  18. Algebraic description of intrinsic modes in nuclei

    SciTech Connect

    Leviatan, A.

    1989-01-01

    We present a procedure for extracting normal modes in algebraic number-conserving systems of interacting bosons relevant for collective states in even-even nuclei. The Hamiltonian is resolved into intrinsic (bandhead related) and collective (in-band related) parts. Shape parameters are introduced through non-spherical boson bases. Intrinsic modes decoupled from the spurious modes are obtained from the intinsic part of the Hamiltonian in the limit of large number of bosons. Intrinsic states are constructed and serve to evaluate electromagnetic transition rates. The method is illustrated for systems with one type of boson as well as with proton-neutron bosons. 28 refs., 1 fig.

  19. Analytical procedures for estimating structural response to acoustic fields generated by advanced launch systems, phase 2

    NASA Technical Reports Server (NTRS)

    Elishakoff, Isaac; Lin, Y. K.; Zhu, Li-Ping; Fang, Jian-Jie; Cai, G. Q.

    1994-01-01

    This report supplements a previous report of the same title submitted in June, 1992. It summarizes additional analytical techniques which have been developed for predicting the response of linear and nonlinear structures to noise excitations generated by large propulsion power plants. The report is divided into nine chapters. The first two deal with incomplete knowledge of boundary conditions of engineering structures. The incomplete knowledge is characterized by a convex set, and its diagnosis is formulated as a multi-hypothesis discrete decision-making algorithm with attendant criteria of adaptive termination.

  20. Late Phase of the Endoplasmic Reticulum Stress Response Pathway Is Regulated by Hog1 MAP Kinase*

    PubMed Central

    Bicknell, Alicia A.; Tourtellotte, Joel; Niwa, Maho

    2010-01-01

    When unfolded proteins accumulate in the endoplasmic reticulum (ER) causing ER stress, the unfolded protein response (UPR) responds rapidly to induce a transcriptional program that functions to alleviate the stress. However, under extreme conditions, when UPR activation is not sufficient to alleviate ER stress, the stress may persist long term. Very little is known about how the cell responds to persistent ER stress that is not resolved by the immediate activation of the UPR. We show that Hog1 MAP kinase becomes phosphorylated during the late stage of ER stress and helps the ER regain homeostasis. Although Hog1 is well known to function in osmotic stress and cell wall integrity pathways, we show that the activation mechanism for Hog1 during ER stress is distinct from both of these pathways. During late stage ER stress, upon phosphorylation, Hog1 translocates into the nucleus and regulates gene expression. Subsequently, Hog1 returns to the cytoplasm, where its phosphorylation levels remain high. From its cytoplasmic location, Hog1 contributes to the activation of autophagy by enhancing the stability of Atg8, a critical autophagy protein. Thus, Hog1 coordinates a multifaceted response to persistent ER stress. PMID:20382742

  1. Acute-Phase Inflammatory Response to Single-Bout HIIT and Endurance Training: A Comparative Study

    PubMed Central

    Kaspar, Felix; Jelinek, Herbert F.; Perkins, Steven; Al-Aubaidy, Hayder A.; deJong, Bev; Butkowski, Eugene

    2016-01-01

    Objective. This study compared acute and late effect of single-bout endurance training (ET) and high-intensity interval training (HIIT) on the plasma levels of four inflammatory cytokines and C-reactive protein and insulin-like growth factor 1. Design. Cohort study with repeated-measures design. Methods. Seven healthy untrained volunteers completed a single bout of ET and HIIT on a cycle ergometer. ET and HIIT sessions were held in random order and at least 7 days apart. Blood was drawn before the interventions and 30 min and 2 days after the training sessions. Plasma samples were analyzed with ELISA for the interleukins (IL), IL-1β, IL-6, and IL-10, monocyte chemoattractant protein-1 (MCP-1), insulin growth factor 1 (IGF-1), and C-reactive protein (CRP). Statistical analysis was with Wilcoxon signed-rank tests. Results. ET led to both a significant acute and long-term inflammatory response with a significant decrease at 30 minutes after exercise in the IL-6/IL-10 ratio (−20%; p = 0.047) and a decrease of MCP-1 (−17.9%; p = 0.03). Conclusion. This study demonstrates that ET affects the inflammatory response more adversely at 30 minutes after exercise compared to HIIT. However, this is compensated by a significant decrease in MCP-1 at two days associated with a reduced risk of atherosclerosis. PMID:27212809

  2. Explicit solvent simulations of the aqueous oxidation potential and reorganization energy for neutral molecules: gas phase, linear solvent response, and non-linear response contributions.

    PubMed

    Guerard, Jennifer J; Tentscher, Peter R; Seijo, Marianne; Samuel Arey, J

    2015-06-14

    First principles simulations were used to predict aqueous one-electron oxidation potentials (Eox) and associated half-cell reorganization energies (λaq) for aniline, phenol, methoxybenzene, imidazole, and dimethylsulfide. We employed quantum mechanical/molecular mechanical (QM/MM) molecular dynamics (MD) simulations of the oxidized and reduced species in an explicit aqueous solvent, followed by EOM-IP-CCSD computations with effective fragment potentials for diabatic energy gaps of solvated clusters, and finally thermodynamic integration of the non-linear solvent response contribution using classical MD. A priori predicted Eox and λaq values exhibit mean absolute errors of 0.17 V and 0.06 eV, respectively, compared to experiment. We also disaggregate Eox into several well-defined free energy properties, including the gas phase adiabatic free energy of ionization (7.73 to 8.82 eV), the solvent-induced shift in the free energy of ionization due to linear solvent response (-2.01 to -2.73 eV), and the contribution from non-linear solvent response (-0.07 to -0.14 eV). The linear solvent response component is further apportioned into contributions from the solvent-induced shift in vertical ionization energy of the reduced species (ΔVIEaq) and the solvent-induced shift in negative vertical electron affinity of the ionized species (ΔNVEAaq). The simulated ΔVIEaq and ΔNVEAaq are found to contribute the principal sources of uncertainty in computational estimates of Eox and λaq. Trends in the magnitudes of disaggregated solvation properties are found to correlate with trends in structural and electronic features of the solute. Finally, conflicting approaches for evaluating the aqueous reorganization energy are contrasted and discussed, and concluding recommendations are given.

  3. Pulmonary Response to Surface-Coated Nanotitanium Dioxide Particles Includes Induction of Acute Phase Response Genes, Inflammatory Cascades, and Changes in MicroRNAs: A Toxicogenomic Study

    PubMed Central

    Halappanavar, Sabina; Jackson, Petra; Williams, Andrew; Jensen, Keld A; Hougaard, Karin S; Vogel, Ulla; Yauk, Carole L; Wallin, Håkan

    2011-01-01

    Titanium dioxide nanoparticles (nanoTiO2) are used in various applications including in paints. NanoTiO2 inhalation may induce pulmonary toxicity and systemic effects. However, the underlying molecular mechanisms are poorly understood. In this study, the effects of inhaled surface-coated nanoTiO2 on pulmonary global messenger RNA (mRNA) and microRNA (miRNA) expression in mouse were characterized to provide insight into the molecular response. Female C57BL/6BomTac mice were exposed for 1 hr daily to 42.4 ± 2.9 (SEM) mg surface-coated nanoTiO2/m3 for 11 consecutive days by inhalation and were sacrificed 5 days following the last exposure. Physicochemical properties of the particles were determined. Pulmonary response to nanoTiO2 was characterized using DNA microarrays and pathway-specific PCR arrays and related to data on pulmonary inflammation from bronchial lavages. NanoTiO2 exposure resulted in increased levels of mRNA for acute phase markers serum amyloid A-1 (Saa1) and serum amyloid A-3 (Saa3), several C-X-C and C-C motif chemokines, and cytokine tumor necrosis factor genes. Protein analysis of Saa1 and 3 showed selective upregulation of Saa3 in lung tissues. Sixteen miRNAs were induced by more than 1.2-fold (adjusted P-value < 0.05) following exposure. Real time polymerase chain reaction confirmed the upregulation of miR-1, miR-449a and revealed dramatic induction of miR-135b (60-fold). Thus, inhalation of surface-coated nanoTiO2 results in changes in the expression of genes associated with acute phase, inflammation and immune response 5 days post exposure with concomitant changes in several miRNAs. The role of these miRNAs in pulmonary response to inhaled particles is unknown and warrants further research. Environ. Mol. Mutagen., 2011. © 2011 Wiley-Liss, Inc.† PMID:21259345

  4. EVALUATING THE HYDROGEOCHEMICAL RESPONSE OF SPRINGS USING PHASE-PLANE PLOTS AND SINGULAR SPECTRUM ANALYSIS

    SciTech Connect

    B. NEWMAN; C. DUFFY; D. HICKMOTT

    2001-04-01

    An ongoing study is focused on understanding the hydrology and geochemistry of three contaminated, perennial, semi-arid zone springs at a high explosives production facility at Los Alamos National Laboratory, in northern New Mexico, USA. Springflow time series were examined using singular spectrum analysis (SSA) to identify the important time-scales affecting flow in the springs. SSA results suggest that springflow has two dominant patterns: a series of low-frequency modes which follow the seasonal and longer-term climate conditions at the site, and a large number of higher frequency modes which display the characteristic ''red noise'' spectrum related to local, short-term weather conditions. Phase-plane plots of {delta}{sup 18}O and spring discharge suggest that high flow conditions are dominated by snowmelt and summer monsoon inputs while low flow conditions can be affected by mixing of fast and slow flow components causing wide variations in {delta}{sup 18}O values. The analysis is being used for development of an efficient strategy for sampling design for environmental monitoring of contaminants that respond to multiple time scales.

  5. Acute phase protein response in heartworm-infected dogs after adulticide treatment.

    PubMed

    Méndez, J C; Carretón, E; Martínez-Subiela, S; Tvarijonaviciute, A; Cerón, J J; Montoya-Alonso, J A

    2015-04-30

    During the adulticide treatment of Dirofilaria immitis the worms die releasing fragments of parasites and causing pulmonary thromboembolisms which could exacerbate the clinical condition. To determine the utility of acute phase proteins (APPs) to monitor the progression of the treatment, different positive [C-reactive protein (CRP), haptoglobin (hp)] and negative [albumin, paraoxonase-1(PON-1)] APPs were measured in 15 heartworm-infected dogs (5 with high and 10 with low parasite burden) following adulticide treatment. The results showed increased concentrations of CRP, decreased concentrations of haptoglobin and PON-1 in infected dogs before starting the treatment. Progressive but not significant increases were observed in PON-1 activity and albumin concentration along the treatment. After the treatment with doxycycline and ivermectine a decrease in CRP and Hp levels was experienced, which could reflect a reduction of the vascular inflammation caused by the elimination of Wolbachia and reduction of microfilariae. Fifteen days after the first melarsomine injection, marked increases in CRP and Hp were observed, which could be due to pulmonary inflammation and thromboembolism caused by the post-adulticide death of the worms. This increase was greater in dogs with high parasite burden. As the pathology disappeared, there was an improvement in the concentrations of CRP and Hp, returning into reference values in dogs with low parasite burden at the end of the treatment. The measurement of CRP and Hp could be a resource of support to evaluate the magnitude of the post-adulticide complications during the adulticide treatment of D. immitis. PMID:25801227

  6. Neural Correlates of Task Cost for Stance Control with an Additional Motor Task: Phase-Locked Electroencephalogram Responses

    PubMed Central

    Hwang, Ing-Shiou; Huang, Cheng-Ya

    2016-01-01

    With appropriate reallocation of central resources, the ability to maintain an erect posture is not necessarily degraded by a concurrent motor task. This study investigated the neural control of a particular postural-suprapostural procedure involving brain mechanisms to solve crosstalk between posture and motor subtasks. Participants completed a single posture task and a dual-task while concurrently conducting force-matching and maintaining a tilted stabilometer stance at a target angle. Stabilometer movements and event-related potentials (ERPs) were recorded. The added force-matching task increased the irregularity of postural response rather than the size of postural response prior to force-matching. In addition, the added force-matching task during stabilometer stance led to marked topographic ERP modulation, with greater P2 positivity in the frontal and sensorimotor-parietal areas of the N1-P2 transitional phase and in the sensorimotor-parietal area of the late P2 phase. The time-frequency distribution of the ERP primary principal component revealed that the dual-task condition manifested more pronounced delta (1–4 Hz) and beta (13–35 Hz) synchronizations but suppressed theta activity (4–8 Hz) before force-matching. The dual-task condition also manifested coherent fronto-parietal delta activity in the P2 period. In addition to a decrease in postural regularity, this study reveals spatio-temporal and temporal-spectral reorganizations of ERPs in the fronto-sensorimotor-parietal network due to the added suprapostural motor task. For a particular set of postural-suprapostural task, the behavior and neural data suggest a facilitatory role of autonomous postural response and central resource expansion with increasing interregional interactions for task-shift and planning the motor-suprapostural task. PMID:27010634

  7. Mechanism of terahertz electromagnetic wave emission from intrinsic Josephson junctions.

    PubMed

    Tachiki, Masashi; Fukuya, Shouta; Koyama, Tomio

    2009-03-27

    Using a 3D parallelepiped model of the stack of intrinsic Josephson junctions, we calculate the cavity resonance modes of Josephson plasma waves excited by external electric currents. The cavity modes accompanied by static phase kinks of the order parameter have been intensively investigated. Our calculation shows that the kink phase state is unfavorable, since the static phase kinks reduce the order parameter amplitude and thus the superconducting condensation energy. We point out that the oscillating magnetic field of the cavity mode penetrates the vacuum from the sample surfaces and the energy of the magnetic field plays an important role to determine the orientation of the cavity resonance mode. On the basis of the above discussions, we calculate the I-V characteristic curve, the THz wave emission intensity and the other physical quantities.

  8. Intrinsic ethics regarding integrated assessment models for climate management.

    PubMed

    Schienke, Erich W; Baum, Seth D; Tuana, Nancy; Davis, Kenneth J; Keller, Klaus

    2011-09-01

    In this essay we develop and argue for the adoption of a more comprehensive model of research ethics than is included within current conceptions of responsible conduct of research (RCR). We argue that our model, which we label the ethical dimensions of scientific research (EDSR), is a more comprehensive approach to encouraging ethically responsible scientific research compared to the currently typically adopted approach in RCR training. This essay focuses on developing a pedagogical approach that enables scientists to better understand and appreciate one important component of this model, what we call intrinsic ethics. Intrinsic ethical issues arise when values and ethical assumptions are embedded within scientific findings and analytical methods. Through a close examination of a case study and its application in teaching, namely, evaluation of climate change integrated assessment models, this paper develops a method and case for including intrinsic ethics within research ethics training to provide scientists with a comprehensive understanding and appreciation of the critical role of values and ethical choices in the production of research outcomes. PMID:20532667

  9. Effect of Intrinsic Ripples on Elasticity of the Graphene Monolayer.

    PubMed

    Lee, Seungjun

    2015-12-01

    The effect of intrinsic ripples on the mechanical response of the graphene monolayer is investigated under uniaxial loading using molecular dynamics (MD) simulations with a focus on nonlinear behavior at a small strain. The calculated stress-strain response shows a nonlinear relation through the entire range without constant slopes as a result of the competition between ripple softening and bond stretching hardening. For a small strain, entropic contribution is dominant due to intrinsic ripples, leading to elasticity softening. As the ripples flatten at increasing strain, the energetic term due to C-C bonds stretching competes with the entropic contribution, followed by energetic dominant deformation. Elasticity softening is enhanced at increased temperature as the ripple amplitude increases. The study shows that the intrinsic ripple of graphene affects elasticity. This result suggests that a change of ripple amplitudes due to various environmental conditions such as temperature, and substrate interactions can lead to a change of the mechanical properties of graphene. The understanding of the rippling effect on the mechanical behavior of 2D materials is useful for strain-based ripple manipulation for their engineering applications.

  10. Effect of Intrinsic Ripples on Elasticity of the Graphene Monolayer

    NASA Astrophysics Data System (ADS)

    Lee, Seungjun

    2015-10-01

    The effect of intrinsic ripples on the mechanical response of the graphene monolayer is investigated under uniaxial loading using molecular dynamics (MD) simulations with a focus on nonlinear behavior at a small strain. The calculated stress-strain response shows a nonlinear relation through the entire range without constant slopes as a result of the competition between ripple softening and bond stretching hardening. For a small strain, entropic contribution is dominant due to intrinsic ripples, leading to elasticity softening. As the ripples flatten at increasing strain, the energetic term due to C-C bonds stretching competes with the entropic contribution, followed by energetic dominant deformation. Elasticity softening is enhanced at increased temperature as the ripple amplitude increases. The study shows that the intrinsic ripple of graphene affects elasticity. This result suggests that a change of ripple amplitudes due to various environmental conditions such as temperature, and substrate interactions can lead to a change of the mechanical properties of graphene. The understanding of the rippling effect on the mechanical behavior of 2D materials is useful for strain-based ripple manipulation for their engineering applications.

  11. Intrinsic ethics regarding integrated assessment models for climate management.

    PubMed

    Schienke, Erich W; Baum, Seth D; Tuana, Nancy; Davis, Kenneth J; Keller, Klaus

    2011-09-01

    In this essay we develop and argue for the adoption of a more comprehensive model of research ethics than is included within current conceptions of responsible conduct of research (RCR). We argue that our model, which we label the ethical dimensions of scientific research (EDSR), is a more comprehensive approach to encouraging ethically responsible scientific research compared to the currently typically adopted approach in RCR training. This essay focuses on developing a pedagogical approach that enables scientists to better understand and appreciate one important component of this model, what we call intrinsic ethics. Intrinsic ethical issues arise when values and ethical assumptions are embedded within scientific findings and analytical methods. Through a close examination of a case study and its application in teaching, namely, evaluation of climate change integrated assessment models, this paper develops a method and case for including intrinsic ethics within research ethics training to provide scientists with a comprehensive understanding and appreciation of the critical role of values and ethical choices in the production of research outcomes.

  12. Characterization of the phase dependent pulmonary response following irritant inhalation exposure to nitrogen dioxide gas

    SciTech Connect

    Siegel, P.D.

    1988-01-01

    The present study utilized NO{sub 2} to fingerprint the biochemical reaction of the pulmonary compartment to oxidative damage and to correlate this with histopathology following acute and subacute exposures to NO{sub 2}. Acute exposure to NO{sub 2} produced dose-dependent immediate increases in the nonenzymatic parameters of pulmonary protein content, protease inhibitor activity and lung weight. The enzymatic activities of lactate dehydrogenase (LDH), choline kinase and beta-glucuronidase were elevated by two days following acute exposure. All of the above parameters were elevated following subacute exposure, however, nonenzymatic manifestations were attenuated with respect to enzymatic alterations. Hydroxyurea-induced granulocytopenia attenuated the increases in activities of LDH and beta-glucuronidase following acute, but not subacute exposures. Cycloheximide-induced protein synthesis inhibition decrease the LDH and beta-glucuronidase response to NO{sub 2} without altering the increases in protein content or protease inhibitor activity.

  13. Identification of the mineral phases responsible for cementation of Lurgi spent oil shale

    SciTech Connect

    Brown, M.; Huntington, G.; Brown, T.

    1991-02-01

    The purpose of this study is to investigate the mineralogical character of the cements that are responsible for the increased strength of the spent oil shale. Several techniques to identify the nature of the cementing agents have been used in this study. X-ray diffraction was used to identify mineral dissolution and formation; scanning electron microscopy (SEM) was used to observe the cementing agents; energy dispersive X-ray analysis (EDXA) was used to provide information on the elemental composition of both the bulk material and the cementing agents; and differential thermal analyses and thermogravimetric analyses were used to document the presence of suspected minerals that may be involved in formation of the cementing material.

  14. Simulation and Evaluation of Phase Transformations and Mechanical Response in the Hot Stamping Process

    NASA Astrophysics Data System (ADS)

    Oldenburg, Mats; Åkerström, Paul; Bergman, Greger; Salomonsson, Per

    2007-05-01

    When producing thin ultra high strength steel components with the hot stamping process it is essential that the final component achieves desirable material properties. This applies in particular to passive automotive safety components. Often the desirable microstructure consists of a mix of martensite and bainite. Therefore, it is of great importance to accurately predict the final microstructure of the component early in the product development process. In this work a model to predict the austenite decomposition into ferrite, pearlite, bainite and martensite during arbitrary cooling paths for thin sheet boron steel is used. The decomposition model is based on Kirkaldy's rate equations and later modifications by Li et al. The modified model accounts for the effect from the added boron. The model is implemented as part of a material subroutine in the Finite Element Program LS-DYNA 970. Both the simulated volume fractions of micro-constituents and hardness profiles show good agreement with the corresponding experimental observations. The phase proportions affect both the thermal and the mechanical properties during the process of continuous cooling and deformation of the material. A thermo-elastic-plastic constitutive model including effects from changes in the microstructure as well as transformation plasticity is implemented in the LS-DYNA code. The material model is used in combination with a thermal shell formulation with quadratic temperature interpolation in the thickness direction to simulate the complete process of simultaneous forming and quenching of sheet metal components. The implemented model is used in coupled thermo-mechanical analysis of the hot stamping process and evaluated by comparing the results from hot stamping experiments. The results from simulations such as local thickness variations, hardness distribution and spring-back in the component show good agreement with experimental results.

  15. Simulation and Evaluation of Phase Transformations and Mechanical Response in the Hot Stamping Process

    SciTech Connect

    Oldenburg, Mats; Salomonsson, Per; Aakerstroem, Paul; Bergman, Greger

    2007-05-17

    When producing thin ultra high strength steel components with the hot stamping process it is essential that the final component achieves desirable material properties. This applies in particular to passive automotive safety components. Often the desirable microstructure consists of a mix of martensite and bainite. Therefore, it is of great importance to accurately predict the final microstructure of the component early in the product development process. In this work a model to predict the austenite decomposition into ferrite, pearlite, bainite and martensite during arbitrary cooling paths for thin sheet boron steel is used. The decomposition model is based on Kirkaldy's rate equations and later modifications by Li et al. The modified model accounts for the effect from the added boron. The model is implemented as part of a material subroutine in the Finite Element Program LS-DYNA 970. Both the simulated volume fractions of micro-constituents and hardness profiles show good agreement with the corresponding experimental observations. The phase proportions affect both the thermal and the mechanical properties