Science.gov

Sample records for active gain medium

  1. Multipolar, time-dynamical model for the loss compensation and lasing of a spherical plasmonic nanoparticle spaser immersed in an active gain medium

    NASA Astrophysics Data System (ADS)

    Veltri, Alessandro; Chipouline, Arkadi; Aradian, Ashod

    2016-09-01

    The plasmonic response of a metal nanoparticle in the presence of surrounding gain elements is studied, using a space and time-dependent model, which integrates a quantum formalism to describe the gain and a classical treatment for the metal. Our model fully takes into account the influence of the system geometry (nanosphere) and offers for the first time, the possibility to describe the temporal evolution of the fields and the coupling among the multipolar modes of the particle. We calculate the lasing threshold value for all multipoles of the spaser, and demonstrate that the dipolar one is lowest. The onset of the lasing instability, in the linear regime, is then studied both with and without external field forcing. We also study the behaviour of the system below the lasing threshold, with the external field, demonstrating the existence of an amplification regime where the nanoparticle’s plasmon is strongly enhanced as the threshold is approached. Finally, a qualitative discussion is provided on later, non-linear stages of the dynamics and the approach to the steady-state of the spaser; in particular, it is shown that, for the considered geometry, the spasing is necessarily multi-modal and multipolar modes are always activated.

  2. Multipolar, time-dynamical model for the loss compensation and lasing of a spherical plasmonic nanoparticle spaser immersed in an active gain medium.

    PubMed

    Veltri, Alessandro; Chipouline, Arkadi; Aradian, Ashod

    2016-01-01

    The plasmonic response of a metal nanoparticle in the presence of surrounding gain elements is studied, using a space and time-dependent model, which integrates a quantum formalism to describe the gain and a classical treatment for the metal. Our model fully takes into account the influence of the system geometry (nanosphere) and offers for the first time, the possibility to describe the temporal evolution of the fields and the coupling among the multipolar modes of the particle. We calculate the lasing threshold value for all multipoles of the spaser, and demonstrate that the dipolar one is lowest. The onset of the lasing instability, in the linear regime, is then studied both with and without external field forcing. We also study the behaviour of the system below the lasing threshold, with the external field, demonstrating the existence of an amplification regime where the nanoparticle's plasmon is strongly enhanced as the threshold is approached. Finally, a qualitative discussion is provided on later, non-linear stages of the dynamics and the approach to the steady-state of the spaser; in particular, it is shown that, for the considered geometry, the spasing is necessarily multi-modal and multipolar modes are always activated. PMID:27625072

  3. Multipolar, time-dynamical model for the loss compensation and lasing of a spherical plasmonic nanoparticle spaser immersed in an active gain medium

    PubMed Central

    Veltri, Alessandro; Chipouline, Arkadi; Aradian, Ashod

    2016-01-01

    The plasmonic response of a metal nanoparticle in the presence of surrounding gain elements is studied, using a space and time-dependent model, which integrates a quantum formalism to describe the gain and a classical treatment for the metal. Our model fully takes into account the influence of the system geometry (nanosphere) and offers for the first time, the possibility to describe the temporal evolution of the fields and the coupling among the multipolar modes of the particle. We calculate the lasing threshold value for all multipoles of the spaser, and demonstrate that the dipolar one is lowest. The onset of the lasing instability, in the linear regime, is then studied both with and without external field forcing. We also study the behaviour of the system below the lasing threshold, with the external field, demonstrating the existence of an amplification regime where the nanoparticle’s plasmon is strongly enhanced as the threshold is approached. Finally, a qualitative discussion is provided on later, non-linear stages of the dynamics and the approach to the steady-state of the spaser; in particular, it is shown that, for the considered geometry, the spasing is necessarily multi-modal and multipolar modes are always activated. PMID:27625072

  4. Sudden gains in behavioural activation for depression.

    PubMed

    Masterson, Ciara; Ekers, David; Gilbody, Simon; Richards, David; Toner-Clewes, Benjamin; McMillan, Dean

    2014-09-01

    Sudden gains have been linked to improved outcomes in cognitive behaviour therapy for depression. The relationship between sudden gains and outcome is less clear in other treatment modalities, including interpersonal psychotherapy and supportive expressive therapy, which may indicate different mechanisms of change between treatment modalities. The current study examined sudden gains in adults meeting diagnostic criteria for depression (N = 40) offered up to 12 sessions of behavioural activation treatment. Sudden gains were found in 42.5% of the sample. Sudden gains occurred early (median pre-gain session 2) and were related to outcome: those who experienced a sudden gain had significantly lower post-treatment scores on the PHQ-9. Furthermore, the proportion meeting the reliable and clinically significant change criteria at end of treatment was higher in the sudden gain group. These findings highlight the importance of understanding the mechanisms by which sudden gains relate to therapy outcome in behavioural activation.

  5. Measurements of the gain medium temperature in an operating Cs DPAL.

    PubMed

    Zhdanov, B V; Rotondaro, M D; Shaffer, M K; Knize, R J

    2016-08-22

    A Mach-Zehnder interferometer was used for contactless measurement of the temperature of the gain medium within a static cell of Cs DPAL. The maximum temperature recorded approached 700° C leading to a significant degradation of laser performance. This work also examined lasing and non-lasing heat deposition and has shown that as much as 85% of the heating in a DPAL gain medium can be attributed to quenching. PMID:27557208

  6. Measurements of the gain medium temperature in an operating Cs DPAL.

    PubMed

    Zhdanov, B V; Rotondaro, M D; Shaffer, M K; Knize, R J

    2016-08-22

    A Mach-Zehnder interferometer was used for contactless measurement of the temperature of the gain medium within a static cell of Cs DPAL. The maximum temperature recorded approached 700° C leading to a significant degradation of laser performance. This work also examined lasing and non-lasing heat deposition and has shown that as much as 85% of the heating in a DPAL gain medium can be attributed to quenching.

  7. 20 CFR 220.141 - Substantial gainful activity, defined.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...) Substantial work activity. Substantial work activity is work activity that involves doing significant physical... 20 Employees' Benefits 1 2011-04-01 2011-04-01 false Substantial gainful activity, defined. 220... RETIREMENT ACT DETERMINING DISABILITY Substantial Gainful Activity § 220.141 Substantial gainful...

  8. 20 CFR 220.141 - Substantial gainful activity, defined.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...) Substantial work activity. Substantial work activity is work activity that involves doing significant physical... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Substantial gainful activity, defined. 220... RETIREMENT ACT DETERMINING DISABILITY Substantial Gainful Activity § 220.141 Substantial gainful...

  9. Quantum noise of a white-light cavity using a double-pumped gain medium

    NASA Astrophysics Data System (ADS)

    Ma, Yiqiu; Miao, Haixing; Zhao, Chunnong; Chen, Yanbei

    2015-08-01

    Laser interferometric gravitational-wave detectors implement Fabry-Pérot cavities to increase their peak sensitivity. However, this is at the cost of reducing their detection bandwidth, which originates from the propagation phase delay of the light. The "white-light-cavity" idea, first proposed by Wicht et al. [Opt. Commun. 34, 431 (1997), 10.1016/S0030-4018(96)00579-2], is to circumvent this limitation by introducing anomalous dispersion, using a double-pumped gain medium, to compensate for such a phase delay. In this article, starting from the Hamiltonian of the atom-light interaction, we apply an input-output formalism to evaluate the quantum noise of the system. We find that apart from the additional noise associated with the parametric amplification process noted by others, the stability condition for the entire system poses an additional constraint. By surveying the parameter regimes where the gain medium remains stable (not lasing) and stationary, we find that there is no net enhancement of the shot-noise-limited sensitivity. Therefore, other gain media or different parameter regimes should be explored for realizing the white-light cavity.

  10. 20 CFR 416.910 - Meaning of substantial gainful activity.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 2 2011-04-01 2011-04-01 false Meaning of substantial gainful activity. 416....910 Meaning of substantial gainful activity. Substantial gainful activity means work that— (a) Involves doing significant and productive physical or mental duties; and (b) Is done (or intended) for...

  11. 20 CFR 416.910 - Meaning of substantial gainful activity.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Meaning of substantial gainful activity. 416....910 Meaning of substantial gainful activity. Substantial gainful activity means work that— (a) Involves doing significant and productive physical or mental duties; and (b) Is done (or intended) for...

  12. High Average Power Laser Gain Medium With Low Optical Distortion Using A Transverse Flowing Liquid Host

    DOEpatents

    Comaskey, Brian J.; Ault, Earl R.; Kuklo, Thomas C.

    2005-07-05

    A high average power, low optical distortion laser gain media is based on a flowing liquid media. A diode laser pumping device with tailored irradiance excites the laser active atom, ion or molecule within the liquid media. A laser active component of the liquid media exhibits energy storage times longer than or comparable to the thermal optical response time of the liquid. A circulation system that provides a closed loop for mixing and circulating the lasing liquid into and out of the optical cavity includes a pump, a diffuser, and a heat exchanger. A liquid flow gain cell includes flow straighteners and flow channel compression.

  13. Gainful Activity and Intimate Partner Aggression in Emerging Adulthood*

    PubMed Central

    Alvira-Hammond, Marta; Longmore, Monica A.; Manning, Wendy D.; Giordano, Peggy C.

    2014-01-01

    Although intimate partner aggression crosses social class boundaries, education and income are important predictors. Yet given that emerging adulthood is a transitional period, completed education and employment, as single measures, are not ideal indicators of socioeconomic status for young people. We examined associations between self-reports of gainful activity, defined as enrollment in school or full-time employment, and intimate partner aggression among young adults in dating, cohabiting, or married relationships (N=648). Both men and women's participation in gainful activity was negatively associated with aggression. We found that when neither partner was gainfully active, individuals reported higher frequency of physical aggression. In cases of gainful activity asymmetry, the gender of the gainfully active partner did not predict intimate partner aggression. Additionally, we found no evidence that the association between gainful activity and frequency of intimate partner aggression differed by union type. PMID:25309829

  14. Photonuclear activation of pure isotopic mediums.

    SciTech Connect

    Grohman, Mark A.; Lukosi, Eric Daniel

    2010-06-01

    This work simulated the response of idealized isotopic U-235, U-238, Th-232, and Pu-239 mediums to photonuclear activation with various photon energies. These simulations were conducted using MCNPX version 2.6.0. It was found that photon energies between 14-16 MeV produce the highest response with respect to neutron production rates from all photonuclear reactions. In all cases, Pu-239 responds the highest, followed by U-238. Th-232 produces more overall neutrons at lower photon energies then U-235 when material thickness is above 3.943 centimeters. The time it takes each isotopic material to reach stable neutron production rates in time is directly proportional to the material thickness and stopping power of the medium, where thicker mediums take longer to reach stable neutron production rates and thinner media display a neutron production plateau effect, due to the lack of significant attenuation of the activating photons in the isotopic mediums. At this time, no neutron sensor system has time resolutions capable of verifying these simulations, but various indirect methods are possible and should be explored for verification of these results.

  15. Theoretical investigation on the strong coupling between a molecule and a metallic nanosphere clad with a gain medium

    NASA Astrophysics Data System (ADS)

    Huang, Jung-Hao; Chang, Railing

    2014-01-01

    Strong coupling between a molecule and a metallic nanosphere clad by a layer of gain medium, which provides compensation for losses in the metal, is investigated theoretically. We self-consistently solve the classical model of a molecule which is described as a damped oscillating dipole, driven by the field reflected back from the metallic surface. It is found that in a broad range of gain level, the frequencies of this coupled system exhibit a splitting substantially larger than the associated damping rate, a signature of strong coupling. As the gain-dissipation balance is optimized, strong coupling occurs even if the molecule is separated from the nanoparticle by a distance as large as several tens of nanometers. Thus through the aid of a gain medium, experimental observation of strong coupling can be easily achieved.

  16. Gain-adaptive vector quantization for medium-rate speech coding

    NASA Astrophysics Data System (ADS)

    Chen, J.-H.; Gersho, A.

    A class of adaptive vector quantizers (VQs) that can dynamically adjust the 'gain' of codevectors according to the input signal level is introduced. The encoder uses a gain estimator to determine a suitable normalization of each input vector prior to VQ coding. The normalized vectors have reduced dynamic range and can then be more efficiently coded. At the receiver, the VQ decoder output is multiplied by the estimated gain. Both forward and backward adaptation are considered and several different gain estimators are compared and evaluated. An approach to optimizing the design of gain estimators is introduced. Some of the more obvious techniques for achieving gain adaptation are substantially less effective than the use of optimized gain estimators. A novel design technique that is needed to generate the appropriate gain-normalized codebook for the vector quantizer is introduced. Experimental results show that a significant gain in segmental SNR can be obtained over nonadaptive VQ with a negligible increase in complexity.

  17. Gain-adaptive vector quantization for medium-rate speech coding

    NASA Technical Reports Server (NTRS)

    Chen, J.-H.; Gersho, A.

    1985-01-01

    A class of adaptive vector quantizers (VQs) that can dynamically adjust the 'gain' of codevectors according to the input signal level is introduced. The encoder uses a gain estimator to determine a suitable normalization of each input vector prior to VQ coding. The normalized vectors have reduced dynamic range and can then be more efficiently coded. At the receiver, the VQ decoder output is multiplied by the estimated gain. Both forward and backward adaptation are considered and several different gain estimators are compared and evaluated. An approach to optimizing the design of gain estimators is introduced. Some of the more obvious techniques for achieving gain adaptation are substantially less effective than the use of optimized gain estimators. A novel design technique that is needed to generate the appropriate gain-normalized codebook for the vector quantizer is introduced. Experimental results show that a significant gain in segmental SNR can be obtained over nonadaptive VQ with a negligible increase in complexity.

  18. Pulsar activation by the interstellar medium?

    NASA Technical Reports Server (NTRS)

    Michel, F. Curtis

    1987-01-01

    Recent work suggests that rotating magnetized neutron stars (i.e., pulsar models) trap plasma instead of emitting it. The trapping arises because nonneutral plasma can be stably trapped within such a magnetosphere provided the overall system charge is nonzero. It has been argued that particles from the interstellar medium would discharge this system, thereby presumably reactivating the system as a pulsar. However, radiation pressure either precludes such discharging (requiring an alternative source of ionization) or pulsar magnetic moments must be almost perfectly aligned with the spin axis (a revolutionary alternative). Indeed, the pulsars for which particles could reach the neutron star are those with periods of at least 3 sec. But those periods are where pulsars become inactive, not active. Conceivably, nulling might represent intermittent accretion of the interstellar medium.

  19. Epigenetic memory gained by priming with osteogenic induction medium improves osteogenesis and other properties of mesenchymal stem cells

    PubMed Central

    Rui, Yunfeng; Xu, Liangliang; Chen, Rui; Zhang, Ting; Lin, Sien; Hou, Yonghui; Liu, Yang; Meng, Fanbiao; Liu, Zhenqing; Ni, Ming; Sze Tsang, Kam; Yang, Fuyuan; Wang, Chen; Chang Chan, Hsiao; Jiang, Xiaohua; Li, Gang

    2015-01-01

    Mesenchymal stem cells (MSCs) are highly plastic cells that are able to transdifferentiate or dedifferentiate under appropriate conditions. In the present study, we reported here that after in vitro induction of osteogenic differentiation, MSCs could be reverted to a primitive stem cell population (dedifferentiated osteogenic MSCs, De-Os-MSCs) with improved cell survival, colony formation, osteogenic potential, migratory capacity and increased expression of Nanog, Oct4 and Sox2. Most importantly, our results showed great superiority of the De-Os-MSCs over untreated MSCs in ectopic bone formation in vivo. Furthermore, Nanog-knockdown in MSCs could reverse these enhanced properties in De-Os-MSCs in vitro, indicating a central role of Nanog in the transcriptional network. In addition, epigenetic regulations including DNA methylation and histone modifications may play important roles in regulating the de-osteogenic differentiation process. And we found decreased methylation and promoter accrual of activating histone marks, such as H3K4me3 and H4ac on both Nanog and Oct4 gene promoters. Taken together, our study demonstrated that epigenetic memory in De-Os-MSCs gained by priming with osteogenic induction medium favored their differentiation along osteoblastic lineage with improved cell survival and migratory abilities, which may have application potential in enhancing their regenerative capacity in mammals. PMID:26053250

  20. Epigenetic memory gained by priming with osteogenic induction medium improves osteogenesis and other properties of mesenchymal stem cells.

    PubMed

    Rui, Yunfeng; Xu, Liangliang; Chen, Rui; Zhang, Ting; Lin, Sien; Hou, Yonghui; Liu, Yang; Meng, Fanbiao; Liu, Zhenqing; Ni, Ming; Tsang, Kam Sze; Yang, Fuyuan; Wang, Chen; Chan, Hsiao Chang; Jiang, Xiaohua; Li, Gang

    2015-01-01

    Mesenchymal stem cells (MSCs) are highly plastic cells that are able to transdifferentiate or dedifferentiate under appropriate conditions. In the present study, we reported here that after in vitro induction of osteogenic differentiation, MSCs could be reverted to a primitive stem cell population (dedifferentiated osteogenic MSCs, De-Os-MSCs) with improved cell survival, colony formation, osteogenic potential, migratory capacity and increased expression of Nanog, Oct4 and Sox2. Most importantly, our results showed great superiority of the De-Os-MSCs over untreated MSCs in ectopic bone formation in vivo. Furthermore, Nanog-knockdown in MSCs could reverse these enhanced properties in De-Os-MSCs in vitro, indicating a central role of Nanog in the transcriptional network. In addition, epigenetic regulations including DNA methylation and histone modifications may play important roles in regulating the de-osteogenic differentiation process. And we found decreased methylation and promoter accrual of activating histone marks, such as H3K4me3 and H4ac on both Nanog and Oct4 gene promoters. Taken together, our study demonstrated that epigenetic memory in De-Os-MSCs gained by priming with osteogenic induction medium favored their differentiation along osteoblastic lineage with improved cell survival and migratory abilities, which may have application potential in enhancing their regenerative capacity in mammals. PMID:26053250

  1. Enhanced optical precursors by Doppler effect via active Raman gain process.

    PubMed

    Peng, Yandong; Niu, Yueping; Zhang, Lida; Yang, Aihong; Jiang, Lin; Gong, Shangqing

    2012-08-15

    A scheme for enhancing precursor pulse by Doppler effect is proposed in a room-temperature active-Raman-gain medium. Due to abnormal dispersion between two gain peaks, main fields are advanced and constructively interfere with optical precursors, which leads to enhancement of the transient pulse at the rise edge of the input. Moreover, after Doppler averaging, the abnormal dispersion intensifies and the constructive interference between precursors and main fields is much strengthened, which boosts the transient spike. Simulation results demonstrate that the peak intensity of precursors could be enhanced nearly 20 times larger than that of the input.

  2. Enhanced optical precursors by Doppler effect via active Raman gain process.

    PubMed

    Peng, Yandong; Niu, Yueping; Zhang, Lida; Yang, Aihong; Jiang, Lin; Gong, Shangqing

    2012-08-15

    A scheme for enhancing precursor pulse by Doppler effect is proposed in a room-temperature active-Raman-gain medium. Due to abnormal dispersion between two gain peaks, main fields are advanced and constructively interfere with optical precursors, which leads to enhancement of the transient pulse at the rise edge of the input. Moreover, after Doppler averaging, the abnormal dispersion intensifies and the constructive interference between precursors and main fields is much strengthened, which boosts the transient spike. Simulation results demonstrate that the peak intensity of precursors could be enhanced nearly 20 times larger than that of the input. PMID:23381248

  3. 20 CFR 404.1510 - Meaning of substantial gainful activity.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 2 2011-04-01 2011-04-01 false Meaning of substantial gainful activity. 404.1510 Section 404.1510 Employees' Benefits SOCIAL SECURITY ADMINISTRATION FEDERAL OLD-AGE, SURVIVORS AND DISABILITY INSURANCE (1950- ) Determining Disability and Blindness Definition of Disability §...

  4. 20 CFR 404.1510 - Meaning of substantial gainful activity.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 2 2012-04-01 2012-04-01 false Meaning of substantial gainful activity. 404.1510 Section 404.1510 Employees' Benefits SOCIAL SECURITY ADMINISTRATION FEDERAL OLD-AGE, SURVIVORS AND DISABILITY INSURANCE (1950- ) Determining Disability and Blindness Definition of Disability §...

  5. 20 CFR 404.1510 - Meaning of substantial gainful activity.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 2 2013-04-01 2013-04-01 false Meaning of substantial gainful activity. 404.1510 Section 404.1510 Employees' Benefits SOCIAL SECURITY ADMINISTRATION FEDERAL OLD-AGE, SURVIVORS AND DISABILITY INSURANCE (1950- ) Determining Disability and Blindness Definition of Disability §...

  6. 20 CFR 404.1510 - Meaning of substantial gainful activity.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 2 2014-04-01 2014-04-01 false Meaning of substantial gainful activity. 404.1510 Section 404.1510 Employees' Benefits SOCIAL SECURITY ADMINISTRATION FEDERAL OLD-AGE, SURVIVORS AND DISABILITY INSURANCE (1950- ) Determining Disability and Blindness Definition of Disability §...

  7. 20 CFR 404.1510 - Meaning of substantial gainful activity.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Meaning of substantial gainful activity. 404.1510 Section 404.1510 Employees' Benefits SOCIAL SECURITY ADMINISTRATION FEDERAL OLD-AGE, SURVIVORS AND DISABILITY INSURANCE (1950- ) Determining Disability and Blindness Definition of Disability §...

  8. Magnetic plasmonic metamaterials in actively pumped host medium and plasmonic nanolaser

    NASA Astrophysics Data System (ADS)

    Sarychev, Andrey K.; Tartakovsky, Gennady

    2006-08-01

    We consider plasmonic nanoantennas immersed in active host medium. Specifically shaped metal nanoantennas can exhibit strong magnetic properties in the optical spectral range due to the excitation of Magnetic Resonance Plasmons (MRP). A case when a metamaterial comprising such nanoantennas can demonstrate both "left-handiness" and negative permeability in the optical range is considered. We show that high losses predicted for optical "left-handed" materials can be compensated in the gain medium. Gains required to achieve local generation in such magnetic active metamaterials are calculated for real metals

  9. Broadly tunable resonant Raman gain and cw lasing in an optically thick Doppler-broadened medium

    NASA Astrophysics Data System (ADS)

    Popov, Alexander K.; Myslivets, Sergei A.; Hinze, Ulf; Tiemann, E.; Wellegehausen, Bernd; Tartakovsky, Gennady

    1999-09-01

    Interactive numerical simulator, based on MATLAB/SIMULINK platform, for virtual experimentation and optimization of frequency tunable optically pumped dimer laser has been created. Nonperturbative theory considering features of quantum coherence and interference effects at Doppler broadened transitions under two strong driving fields accounting for collisions and other kinetic processes in vapor-gas mixture as well as for propagation effects in optically thick medium is developed. The results are in good agreement with real experiments.

  10. Active rc filter permits easy trade-off of amplifier gain and sensitivity to gain

    NASA Technical Reports Server (NTRS)

    Kerwin, W. J.; Shaffer, C. V.

    1968-01-01

    Passive RC network was designed with zeros of transmission in the right half of the complex frequency plane in the feedback loop of a simple negative-gain amplifier. The proper positioning provides any desired trade-off between amplifier gain and sensitivity to amplifier gain.

  11. Toward the realization of erbium-doped GaN bulk crystals as a gain medium for high energy lasers

    NASA Astrophysics Data System (ADS)

    Sun, Z. Y.; Li, J.; Zhao, W. P.; Lin, J. Y.; Jiang, H. X.

    2016-08-01

    Er-doped GaN (Er:GaN) is a promising candidate as a gain medium for solid-state high energy lasers (HELs) at the technologically important and eye-safe 1.54 μm wavelength window, as GaN has superior thermal properties over traditional laser gain materials such as Nd:YAG. However, the attainment of wafer-scale Er:GaN bulk or quasi-bulk crystals is a prerequisite to realize the full potential of Er:GaN as a gain medium for HELs. We report the realization of freestanding Er:GaN wafers of 2-in. in diameter with a thickness on the millimeter scale. These freestanding wafers were obtained via growth by hydride vapor phase epitaxy in conjunction with a laser-lift-off process. An Er doping level of 1.4 × 1020 atoms/cm3 has been confirmed by secondary ion mass spectrometry measurements. The freestanding Er:GaN wafers exhibit strong photoluminescent emission at 1.54 μm with its emission intensity increasing dramatically with wafer thickness under 980 nm resonant excitation. A low thermal quenching of 10% was measured for the 1.54 μm emission intensity between 10 K and 300 K. This work represents a significant step in providing a practical approach for producing Er:GaN materials with sufficient thicknesses and dimensions to enable the design of gain media in various geometries, allowing for the production of HELs with improved lasing efficiency, atmosphere transmission, and eye-safety.

  12. 20 CFR 416.972 - What we mean by substantial gainful activity.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... work activity that involves doing significant physical or mental activities. Your work may be... 20 Employees' Benefits 2 2011-04-01 2011-04-01 false What we mean by substantial gainful activity... Activity § 416.972 What we mean by substantial gainful activity. Substantial gainful activity is...

  13. Analytical model of optical field distribution of thin disk laser with thermal-optical aberration gain medium

    NASA Astrophysics Data System (ADS)

    Zhu, Guangzhi; Qiu, Yuli; Wang, Zexiong; Zhu, Xiao; Zhu, Changhong

    2016-08-01

    An analytical model is developed to analyze the optical field distribution of thin disk laser with a thermal-optical aberration gain medium. The fundamental mode field distribution is calculated by using the eigenvector method of the resonator transit matrix for different pumping parameters. The analytical results show that the uniformity of the pumping spot is an important factor that impacts the beam quality of thin disk laser. The uniform pumping spot is beneficial to decrease thermal aberration and Optical Path Difference (OPD) of thin disk crystal, and to improve the beam quality. However, the beam quality still decreases slightly with the increasing of pumping intensity under the uniform pumping condition. The main reason for degradation of beam quality is the aspherical part of OPD which leads to diffraction losses of the resonator and wavefront deformation.

  14. Rigorous theoretical analysis of a surface-plasmon nanolaser with monolayer MoS2 gain medium.

    PubMed

    Meng, Xiang; Grote, Richard R; Jin, Wencan; Dadap, Jerry I; Panoiu, Nicolae C; Osgood, Richard M

    2016-06-01

    Lasers based on monolayer (ML) transition-metal dichalcogenide semiconductor crystals have the potential for low threshold operation and a small device footprint; however, nanophotonic engineering is required to maximize the interaction between the optical fields and the three-atom-thick gain medium. Here, we develop a theoretical model to design a direct bandgap optically pumped nanophotonic integrated laser. Our device utilizes a gap-surface-plasmon optical mode to achieve subwavelength optical confinement and consists of a high-index GaP nanowire atop an ML MoS2 film on an Ag substrate. The optical field and material medium are analyzed using a three dimensional finite-difference time-domain method and a first-principles calculation based on the density functional theory, respectively. The nanolaser is designed to have a threshold of ∼0.6  μW under quasi-continuous wave operation on an excitonic transition at room temperature. PMID:27244433

  15. PHYSICAL BASIS OF QUANTUM ELECTRONICS: Role of a high gain of the medium in superradiance generation and in observation of coherent effects in semiconductor lasers

    NASA Astrophysics Data System (ADS)

    Vasil'ev, Petr P.

    1999-10-01

    A theoretical model of superradiant pulse generation in semiconductor laser structures is developed. It is shown that a high optical gain of the medium can overcome phase relaxation and results in a built-up superradiant state (macroscopic dipole) in an assembly of electron—hole pairs on a time scale much longer than the characteristic polarisation relaxation time T2. A criterion of the superradiance generation is the condition αcmT2>1, where α is the gain coefficient and cm is the speed of light in the medium. The theoretical model describes both qualitatively and quantitatively the author's own experimental results.

  16. Linear analysis of active-medium two-beam accelerator

    NASA Astrophysics Data System (ADS)

    Voin, Miron; Schächter, Levi

    2015-07-01

    We present detailed development of the linear theory of wakefield amplification by active medium and its possible application to a two-beam accelerator (TBA) is discussed. A relativistic train of triggering microbunches traveling along a vacuum channel in an active medium confined by a cylindrical waveguide excites Cherenkov wake in the medium. The wake is a superposition of azimuthally symmetric transverse magnetic modes propagating along a confining waveguide, with a phase velocity equal to the velocity of the triggering bunches. The structure may be designed in such a way that the frequency of one of the modes is close to active-medium resonant frequency, resulting in amplification of the former and domination of a single mode far behind the trigger bunches. Another electron bunch placed in proper phase with the amplified wakefield may be accelerated by the latter. Importantly, the energy for acceleration is provided by the active medium and not the drive bunch as in a traditional TBA. Based on a simplified model, we analyze extensively the impact of various parameters on the wakefield amplification process.

  17. The Calibration of AVHRR/3 Visible Dual Gain Using Meteosat-8 as a MODIS Calibration Transfer Medium

    NASA Technical Reports Server (NTRS)

    Avey, Lance; Garber, Donald; Nguyen, Louis; Minnis, Patrick

    2007-01-01

    This viewgraph presentation reviews the NOAA-17 AVHRR visible channels calibrated against MET-8/MODIS using dual gain regression methods. The topics include: 1) Motivation; 2) Methodology; 3) Dual Gain Regression Methods; 4) Examples of Regression methods; 5) AVHRR/3 Regression Strategy; 6) Cross-Calibration Method; 7) Spectral Response Functions; 8) MET8/NOAA-17; 9) Example of gain ratio adjustment; 10) Effect of mixed low/high count FOV; 11) Monitor dual gains over time; and 12) Conclusions

  18. Active microwave remote sensing of an anisotropic random medium layer

    NASA Technical Reports Server (NTRS)

    Lee, J. K.; Kong, J. A.

    1985-01-01

    A two-layer anisotropic random medium model has been developed to study the active remote sensing of the earth. The dyadic Green's function for a two-layer anisotropic medium is developed and used in conjunction with the first-order Born approximation to calculate the backscattering coefficients. It is shown that strong cross-polarization occurs in the single scattering process and is indispensable in the interpretation of radar measurements of sea ice at different frequencies, polarizations, and viewing angles. The effects of anisotropy on the angular responses of backscattering coefficients are also illustrated.

  19. Plasma-activated medium induced apoptosis on tumor cells

    NASA Astrophysics Data System (ADS)

    Hori, Masaru; Tanaka, Hiromasa; Mizuno, Masaaki; Nakamura, Kae; Kajiyama, Hiroaki; Takeda, Keigo; Ishikawa, Kenji; Kano, Hiroyuki; Kikkawa, Fumitaka

    2013-09-01

    The non-equilibrium atmospheric pressure plasma (NEAPP) has attracted attention in cancer therapy. In this study, the fresh medium was treated with our developed NEAPP, ultra-high electron density (approximately 2 × 1016 cm-3). The medium called the plasma-activated medium (PAM) killed not normal cells but tumor cells through induction of apoptosis. Cell proliferation assays showed that the tumor cells were selectively killed by the PAM. Those cells induced apoptosis using an apoptotic molecular marker, cleaved Caspase3/7. The molecular mechanisms of PAM-mediated apoptosis in the tumor cells were also found that the PAM downregulated the expression of AKT kinase, a marker molecule in a survival signal transduction pathway. These results suggest that PAM may be a promising tool for tumor therapy by downregulating the survival signals in cancers.

  20. Time-dependent theory for random lasers in the presence of an inhomogeneous broadened gain medium such as PbSe quantum dots.

    PubMed

    Ardakani, Abbas Ghasempour; Mahdavi, Seyed Mohammad; Bahrampour, Ali Reza

    2013-02-20

    Time-dependent model is presented to simulate random lasers in the presence of an inhomogeneous gain medium. PbSe quantum dots (QDs) with an arbitrary size distribution are treated as an inhomogeneous gain medium. By introducing inhomogeneity of the PbSe QDs in polarization, rate, and Maxwell's equations, our model is constructed for a one-dimensional disordered system. By employing the finite difference time-domain method, the governing equations are numerically solved and lasing spectra and spatial distribution of the electric field are calculated. The effect of increasing the pumping rate on the laser characteristics is investigated. The results show that the number of lasing modes and their intensities increase with pumping rate. It is also demonstrated that the emission spectra depend on the standard deviation of the Gaussian distribution function. Increasing the standard deviation leads to reduction of the laser intensity.

  1. Envelope evolution of a laser pulse in an active medium

    SciTech Connect

    Fisher, D.L.; Tajima, T.; Downer, M.C.; Siders, C.W.

    1994-11-01

    The authors show that the envelope velocity, v{sub env}, of a short laser pulse can, via propagation in an active medium, be made less than, equal to, or even greater than c, the vacuum phase velocity of light. Simulation results, based on moving frame propagation equations coupling the laser pulse, active medium and plasma, are presented, as well as equations that determines the design value of super- and sub-luminous v{sub env}. In this simulation the laser pulse evolves in time in a moving frame as opposed to their earlier work where the profile was fixed. The elimination of phase slippage and pump depletion effects in the laser wakefield accelerator is discussed as a particular application. Finally they discuss media properties necessary for an experimental realization of this technique.

  2. 26 CFR 7.105-2 - Substantial gainful activity.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ..., institutional therapy or training, school attendance, clubs, social programs, and similar activities is not... relative for one or two hours a day by performing duties such as washing dishes, answering...

  3. 26 CFR 7.105-2 - Substantial gainful activity.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ..., institutional therapy or training, school attendance, clubs, social programs, and similar activities is not... relative for one or two hours a day by performing duties such as washing dishes, answering...

  4. 26 CFR 7.105-2 - Substantial gainful activity.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ..., institutional therapy or training, school attendance, clubs, social programs, and similar activities is not.... Example (1). Before retirement on disability, taxpayer worked for a hotel as night desk clerk. After retirement, the taxpayer is hired by another hotel as night desk clerk at a rate of pay exceeding the...

  5. Phase Segregation of Passive Advective Particles in an Active Medium

    NASA Astrophysics Data System (ADS)

    Das, Amit; Polley, Anirban; Rao, Madan

    2016-02-01

    Localized contractile configurations or asters spontaneously appear and disappear as emergent structures in the collective stochastic dynamics of active polar actomyosin filaments. Passive particles which (un)bind to the active filaments get advected into the asters, forming transient clusters. We study the phase segregation of such passive advective scalars in a medium of dynamic asters, as a function of the aster density and the ratio of the rates of aster remodeling to particle diffusion. The dynamics of coarsening shows a violation of Porod behavior; the growing domains have diffuse interfaces and low interfacial tension. The phase-segregated steady state shows strong macroscopic fluctuations characterized by multiscaling and intermittency, signifying rapid reorganization of macroscopic structures. We expect these unique nonequilibrium features to manifest in the actin-dependent molecular clustering at the cell surface.

  6. Neighborhood factors associated with physical activity and adequacy of weight gain during pregnancy

    EPA Science Inventory

    Healthy diet, physical activity, smoking, and adequate weight gain are all associated with maternal health and fetal growth during pregnancy. Neighborhood characteristics have been associated with poor maternal and child health outcomes, yet conceptualization of potential mechani...

  7. Modeling the gain and bandwidth of submicron active layer n+-i-p+ avalanche photodiode

    NASA Astrophysics Data System (ADS)

    Majumder, Kanishka; Das, N. R.

    2012-10-01

    The electron initiated avalanche gain and bandwidth are calculated for thin submicron GaAs n+-i-p+ avalanche photodiode. A model is used to estimate the avalanche build-up of carriers in the active multiplication layer considering the dead-space effect. In the model, the carriers are identified both by their energy and position in the multiplication region. The excess energy of the carriers above threshold is assumed to be equally distributed among the carriers generated after impact ionization. The gain versus bias and bandwidth versus gain characteristics of the device are also demonstrated for different active layer thicknesses of the APD.

  8. INFLUENCE OF GROWTH MEDIUM ON ASSIMILATORY ACTIVITIES OF ESCHERICHIA COLI

    PubMed Central

    Clifton, C. E.

    1963-01-01

    Clifton, C. E. (Stanford University, Stanford, Calif.). Influence of growth medium on assimilatory activities of Escherichia coli. J. Bacteriol. 85:1371–1377. 1963.—Nutrient agargrown cells assimilate about 50% of the glucose added to washed suspensions (phosphate buffer, pH 7.2, 30 C), as indicated by O2 consumption or C14-uptake from uniformly labeled glucose. Most of the nonassimilated glucose is oxidized, but a small portion remains in forms other than glucose in the suspension medium. Cells from glucose agar, however, assimilate only about 20 to 30% of the U-glucose and ferment a considerable portion of the remainder, the extent of each being determined in part at least by growth conditions. Evidence is presented that this behavior is the result of metabolic controls induced during growth. C14 from U-glucose appeared in all fractions of either agar- or glucose agar-grown cells, the highest percentage being present in cellular matter insoluble in hot 5% trichloroacetic acid. Data on the distribution of C14 from 1-, 2-, and 6-glucose, and from acetate and pyruvate, are also presented. PMID:14047232

  9. Maintaining a High Physical Activity Level Over 20 Years and Weight Gain

    PubMed Central

    Hankinson, Arlene L.; Daviglus, Martha L.; Bouchard, Claude; Carnethon, Mercedes; Lewis, Cora E.; Schreiner, Pamela J.; Liu, Kiang; Sidney, Stephen

    2013-01-01

    Context Data supporting physical activity guidelines to prevent long-term weight gain are sparse, particularly during the period when the highest risk of weight gain occurs. Objective To evaluate the relationship between habitual activity levels and changes in body mass index (BMI) and waist circumference over 20 years. Design, Setting, and Participants The Coronary Artery Risk Development in Young Adults (CARDIA) study is a prospective longitudinal study with 20 years of follow-up, 1985-86 to 2005-06. Habitual activity was defined as maintaining high, moderate, and low activity levels based on sex-specific tertiles of activity scores at baseline. Participants comprised a population-based multi-center cohort (Chicago, Illinois; Birmingham, Alabama; Minneapolis, Minnesota; and Oakland, California) of 3554 men and women aged 18 to 30 years at baseline. Main Outcome Measures Average annual changes in BMI and waist circumference Results Over 20 years, maintaining high levels of activity was associated with smaller gains in BMI and waist circumference compared with low activity levels after adjustment for race, baseline BMI, age, education, cigarette smoking status, alcohol use, and energy intake. Men maintaining high activity gained 2.6 fewer kilograms (+ 0.15 BMI units per year; 95 % confidence interval [CI] 0.11-0.18 vs +0.20 in the lower activity group; 95% CI, 0.17-0.23) and women maintaining higher activity gained 6.1 fewer kilograms (+0.17 BMI units per year; 95 % CI, 0.12-0.21 vs. +0.30 in the lower activity group; 95 % CI, 0.25-0.34). Men maintaining high activity gained 3.1 fewer centimeters in waist circumference (+0.52 cm per year; 95 % CI, 0.43-0.61 cm vs 0.67 cm in the lower activity group; 95 % CI, 0.60-0.75) and women maintaining higher activity gained 3.8 fewer centimeters (+0.49 cm per year; 95 % CI, 0.39-0.58 vs 0.67 cm in the lower activity group; 95 % CI, 0.60-0.75). Conclusion Maintaining high activity levels through young adulthood may lessen

  10. Anterior cingulate activity to monetary loss and basal ganglia activity to monetary gain uniquely contribute to the feedback negativity

    PubMed Central

    Foti, Dan; Weinberg, Anna; Bernat, Edward M.; Proudfit, Greg H.

    2014-01-01

    Objective The feedback negativity (FN) is an event-related potential that differentiates unfavorable versus favorable outcomes. Although thought to reflect error-related activity within the anterior cingulate cortex, recent work indicates the FN may also reflect reward-related activity that has been linked to the basal ganglia. To date, it remains unclear how to reconcile these conflicting perspectives. Methods We decomposed the FN by applying time-frequency analysis to isolate activity unique to monetary losses and gains. The FN was recorded from 84 individuals during a laboratory gambling task. Results Two signals contributed to the FN elicited by unpredictable outcomes: theta activity (4-7 Hz) was increased following monetary loss, and delta activity (< 3 Hz) was increased following monetary gain. Predictable outcomes elicited delta but not theta activity. Source analysis revealed distinct generators, with loss-related theta localized to the anterior cingulate cortex and gain-related delta to a possible source in the striatum. Symptoms of depression, anxiety, and stress reactivity were specifically associated with blunted gain-related delta. Conclusions The FN may be a composite of loss- and gain-related neural activity, reflecting distinct facets of reward processing. Significance Gain-related delta activity may provide unique information about reward dysfunction in major depression and other internalizing psychopathology. PMID:25454338

  11. Active mode-locking of mid-infrared quantum cascade lasers with short gain recovery time.

    PubMed

    Wang, Yongrui; Belyanin, Alexey

    2015-02-23

    We investigate the dynamics of actively modulated mid-infrared quantum cascade lasers (QCLs) using space- and time-domain simulations of coupled density matrix and Maxwell equations with resonant tunneling current taken into account. We show that it is possible to achieve active mode locking and stable generation of picosecond pulses in high performance QCLs with a vertical laser transition and a short gain recovery time by bias modulation of a short section of a monolithic Fabry-Perot cavity. In fact, active mode locking in QCLs with a short gain recovery time turns out to be more robust to the variation of parameters as compared to previously studied lasers with a long gain recovery time. We investigate the effects of spatial hole burning and phase locking on the laser output.

  12. Years of Life Gained Due to Leisure-Time Physical Activity in the United States

    PubMed Central

    Janssen, Ian; Carson, Valerie; Lee, I-Min; Katzmarzyk, Peter T.; Blair, Steven N.

    2013-01-01

    Background Physical inactivity is an important modifiable risk factor for non-communicable disease. The degree to which physical activity affects the life expectancy of Americans is unknown. This study estimated the potential years of life gained due to leisure-time physical activity across the adult lifespan in the United States. Methods Data from the National Health and Nutrition Examination Survey (2007–2010), National Health Interview Study mortality linkage (1990–2006), and US Life Tables (2006) were used to estimate and compare life expectancy at each age of adult life for inactive (no moderate-to-vigorous physical activity), somewhat active (some moderate-to-vigorous activity but <500 metabolic equivalent min/week) and active (≥500 metabolic equivalent min/week of moderate-to-vigorous activity) adults. Analyses were conducted in 2012. Results Somewhat active and active non-Hispanic white men had a life expectancy at age 20 that was around 2.4 years longer than the inactive men; this life expectancy advantage was 1.2 years at age 80. Similar observations were made in non-Hispanic white women, with a higher life expectancy within the active category of 3.0 years at age 20 and 1.6 years at age 80. In non-Hispanic black women, as many as 5.5 potential years of life were gained due to physical activity. Significant increases in longevity were also observed within somewhat active and active non-Hispanic black men; however, among Hispanics the years of life gained estimates were more variable and not significantly different from 0 years gained. Conclusions Leisure-time physical activity is associated with increases in longevity in the United States. PMID:23253646

  13. Goos-Hänchen shifts of partially coherent light beams from a cavity with a four-level Raman gain medium

    NASA Astrophysics Data System (ADS)

    Ziauddin; Lee, Ray-Kuang; Qamar, Sajid

    2016-09-01

    We theoretically investigate spatial and angular Goos-Hänchen (GH) shifts (both negative and positive) in the reflected light for a partial coherent light incident on a cavity. A four-level Raman gain atomic medium is considered in a cavity. The effects of spatial coherence, beam width, and mode index of partial coherent light fields on spatial and angular GH shifts are studied. Our results reveal that a large magnitude of negative and positive GH shifts in the reflected light is achievable with the introduction of partial coherent light fields. Furthermore, the amplitude of spatial (negative and positive) GH shifts are sharply affected by the partial coherent light beam as compared to angular (negative and positive) GH shifts in the reflected light.

  14. Two-phase flow in a chemically active porous medium

    SciTech Connect

    Darmon, Alexandre Dauchot, Olivier; Benzaquen, Michael; Salez, Thomas

    2014-12-28

    We study the problem of the transformation of a given reactant species into an immiscible product species, as they flow through a chemically active porous medium. We derive the equation governing the evolution of the volume fraction of the species, in a one-dimensional macroscopic description, identify the relevant dimensionless numbers, and provide simple models for capillary pressure and relative permeabilities, which are quantities of crucial importance when tackling multiphase flows in porous media. We set the domain of validity of our models and discuss the importance of viscous coupling terms in the extended Darcy’s law. We investigate numerically the steady regime and demonstrate that the spatial transformation rate of the species along the reactor is non-monotonous, as testified by the existence of an inflection point in the volume fraction profiles. We obtain the scaling of the location of this inflection point with the dimensionless lengths of the problem. Eventually, we provide key elements for optimization of the reactor.

  15. ACTIVE MEDIA: Dynamics of growth of inhomogeneities in the active medium of a liquid laser

    NASA Astrophysics Data System (ADS)

    Barikhin, B. A.; Ivanov, A. Yu; Kudryavkin, E. V.; Nedolugov, V. I.

    1991-07-01

    Fast cinematography of holograms and of shadow and interference patterns was combined with an acoustic method in a study of the dynamics of growth of inhomogeneities in the active medium of a coaxially pumped dye laser. The main mechanism of the formation of these inhomogeneities was related to acoustic waves created by the deformation of the walls of a dye cell created by electrical pulses applied to the pump flashlamp. Multipulse operation of this laser could be achieved and the off-duty factor could be reduced if the active medium was excited by the strongest possible pump pulses.

  16. Spontaneous regional brain activity links restrained eating to later weight gain among young women.

    PubMed

    Dong, Debo; Jackson, Todd; Wang, Yulin; Chen, Hong

    2015-07-01

    Theory and prospective studies have linked restrained eating (RE) to risk for future weight gain and the onset of obesity, but little is known about resting state neural activity that may underlie this association. To address this gap, resting fMRI was used to test the extent to which spontaneous neural activity in regions associated with inhibitory control and food reward account for potential relations between baseline RE levels and changes in body weight among dieters over a one-year interval. Spontaneous regional activity patterns corresponding to RE were assessed among 50 young women using regional homogeneity (ReHo) analysis, which measured temporal synchronization of spontaneous fluctuations within a food deprivation condition. Analyses indicated higher baseline RE scores predicted more weight gain at a one-year follow-up. Furthermore, food-deprived dieting women with high dietary restraint scores exhibited more spontaneous local activity in brain regions associated with the expectation and valuation for food reward [i.e., orbitofrontal cortex (OFC)/ventromedial prefrontal cortex (VMPFC)] and reduced spontaneous local activity in inhibitory control regions [i.e., bilateral dorsal-lateral prefrontal cortex (DLPFC)] at baseline. Notably, the association between baseline RE and follow-up weight gain was mediated by decreased local synchronization of the right DLPFC in particular and, to a lesser degree, increased local synchronization of the right VMPFC. In conjunction with previous research, these findings highlight possible neural mechanisms underlying the relation between RE and risk for weight gain. PMID:26004091

  17. Spontaneous regional brain activity links restrained eating to later weight gain among young women.

    PubMed

    Dong, Debo; Jackson, Todd; Wang, Yulin; Chen, Hong

    2015-07-01

    Theory and prospective studies have linked restrained eating (RE) to risk for future weight gain and the onset of obesity, but little is known about resting state neural activity that may underlie this association. To address this gap, resting fMRI was used to test the extent to which spontaneous neural activity in regions associated with inhibitory control and food reward account for potential relations between baseline RE levels and changes in body weight among dieters over a one-year interval. Spontaneous regional activity patterns corresponding to RE were assessed among 50 young women using regional homogeneity (ReHo) analysis, which measured temporal synchronization of spontaneous fluctuations within a food deprivation condition. Analyses indicated higher baseline RE scores predicted more weight gain at a one-year follow-up. Furthermore, food-deprived dieting women with high dietary restraint scores exhibited more spontaneous local activity in brain regions associated with the expectation and valuation for food reward [i.e., orbitofrontal cortex (OFC)/ventromedial prefrontal cortex (VMPFC)] and reduced spontaneous local activity in inhibitory control regions [i.e., bilateral dorsal-lateral prefrontal cortex (DLPFC)] at baseline. Notably, the association between baseline RE and follow-up weight gain was mediated by decreased local synchronization of the right DLPFC in particular and, to a lesser degree, increased local synchronization of the right VMPFC. In conjunction with previous research, these findings highlight possible neural mechanisms underlying the relation between RE and risk for weight gain.

  18. External locus of control contributes to racial disparities in memory and reasoning training gains in ACTIVE

    PubMed Central

    Zahodne, Laura B.; Meyer, Oanh L.; Choi, Eunhee; Thomas, Michael L.; Willis, Sherry L.; Marsiske, Michael; Gross, Alden L.; Rebok, George W.; Parisi, Jeanine M.

    2015-01-01

    Racial disparities in cognitive outcomes may be partly explained by differences in locus of control. African Americans report more external locus of control than non-Hispanic Whites, and external locus of control is associated with poorer health and cognition. The aims of this study were to compare cognitive training gains between African American and non-Hispanic White participants in the Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE) study and determine whether racial differences in training gains are mediated by locus of control. The sample comprised 2,062 (26% African American) adults aged 65 and older who participated in memory, reasoning, or speed training. Latent growth curve models evaluated predictors of 10-year cognitive trajectories separately by training group. Multiple group modeling examined associations between training gains and locus of control across racial groups. Compared to non-Hispanic Whites, African Americans evidenced less improvement in memory and reasoning performance after training. These effects were partially mediated by locus of control, controlling for age, sex, education, health, depression, testing site, and initial cognitive ability. African Americans reported more external locus of control, which was associated with smaller training gains. External locus of control also had a stronger negative association with reasoning training gain for African Americans than for Whites. No racial difference in training gain was identified for speed training. Future intervention research with African Americans should test whether explicitly targeting external locus of control leads to greater cognitive improvement following cognitive training. PMID:26237116

  19. The relationship between trunk muscle activation and trunk stiffness: examining a non-constant stiffness gain.

    PubMed

    Brown, Stephen H M; McGill, Stuart M

    2010-12-01

    The relationship between muscle activation, force and stiffness needs to be known to interpret the stability state of the spine. To test the relationship between these variables, a quick release approach was used to match quantified torso stiffness with an EMG activation-based estimate of individual muscle stiffnesses. The relationship between activation, force and stiffness was modelled as k = q x F/l, where k, F and l are muscle stiffness, force and length, respectively, and q is the dimensionless stiffness gain relating these variables. Under the tested experimental scenario, the 'stiffness gain', q, which linked activation with stiffness, demonstrated a decreasing trend with increasing levels of torso muscle activation. This highlights the likelihood that the choice of a single q value may be over simplistic to relate force to stiffness in muscles that control the spine. This has implications for understanding the potential for spine instability in situations requiring high muscular demand.

  20. Insulin enhances the gain of arterial baroreflex control of muscle sympathetic nerve activity in humans.

    PubMed

    Young, Colin N; Deo, Shekhar H; Chaudhary, Kunal; Thyfault, John P; Fadel, Paul J

    2010-09-15

    Recent animal studies indicate that insulin increases arterial baroreflex control of lumbar sympathetic nerve activity; however, the extent to which these findings can be extrapolated to humans is unknown. To begin to address this, muscle sympathetic nerve activity (MSNA) and arterial blood pressure were measured in 19 healthy subjects (27 ± 1 years) before, and for 120 min following, two common methodologies used to evoke sustained increases in plasma insulin: a mixed meal and a hyperinsulinaemic euglycaemic clamp. Weighted linear regression analysis between MSNA and diastolic blood pressure was used to determine the gain (i.e. sensitivity) of arterial baroreflex control of MSNA. Plasma insulin was significantly elevated within 30 min following meal intake (34 ± 6 uIU ml(1); P < 0.05) and remained above baseline for up to 120 min. Similarly, after meal intake, arterial baroreflex-MSNA gain for burst incidence and total MSNA was increased and remained elevated for the duration of the protocol (e.g. burst incidence gain: 3.29 ± 0.54 baseline vs. 5.64 ± 0.67 bursts (100 heart beats)(1) mmHg(1) at 120 min; P < 0.05). During the hyperinsulinaemic euglycaemic clamp, in which insulin was elevated to postprandial concentrations (42 ± 6 μIU ml(1); P < 0.05), while glucose was maintained constant, arterial baroreflex-MSNA gain was similarly enhanced (e.g. burst incidence gain: 2.44 ± 0.29 baseline vs. 4.74 ± 0.71 bursts (100 heart beats)(1) mmHg(1) at 120 min; P < 0.05). Importantly, during time control experiments, with sustained fasting insulin concentrations, the arterial baroreflex-MSNA gain remained unchanged. These findings demonstrate, for the first time in healthy humans, that increases in plasma insulin enhance the gain of arterial baroreflex control of MSNA.

  1. 20 CFR 404.1572 - What we mean by substantial gainful activity.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 2 2011-04-01 2011-04-01 false What we mean by substantial gainful activity. 404.1572 Section 404.1572 Employees' Benefits SOCIAL SECURITY ADMINISTRATION FEDERAL OLD-AGE, SURVIVORS AND DISABILITY INSURANCE (1950- ) Determining Disability and Blindness Substantial...

  2. 20 CFR 404.1572 - What we mean by substantial gainful activity.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 2 2014-04-01 2014-04-01 false What we mean by substantial gainful activity. 404.1572 Section 404.1572 Employees' Benefits SOCIAL SECURITY ADMINISTRATION FEDERAL OLD-AGE, SURVIVORS AND DISABILITY INSURANCE (1950- ) Determining Disability and Blindness Substantial...

  3. 20 CFR 404.1572 - What we mean by substantial gainful activity.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false What we mean by substantial gainful activity. 404.1572 Section 404.1572 Employees' Benefits SOCIAL SECURITY ADMINISTRATION FEDERAL OLD-AGE, SURVIVORS AND DISABILITY INSURANCE (1950- ) Determining Disability and Blindness Substantial...

  4. 20 CFR 404.1572 - What we mean by substantial gainful activity.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 2 2012-04-01 2012-04-01 false What we mean by substantial gainful activity. 404.1572 Section 404.1572 Employees' Benefits SOCIAL SECURITY ADMINISTRATION FEDERAL OLD-AGE, SURVIVORS AND DISABILITY INSURANCE (1950- ) Determining Disability and Blindness Substantial...

  5. 20 CFR 404.1572 - What we mean by substantial gainful activity.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 2 2013-04-01 2013-04-01 false What we mean by substantial gainful activity. 404.1572 Section 404.1572 Employees' Benefits SOCIAL SECURITY ADMINISTRATION FEDERAL OLD-AGE, SURVIVORS AND DISABILITY INSURANCE (1950- ) Determining Disability and Blindness Substantial...

  6. Optical filter finesses enhancement based on nested coupled cavities and active medium

    NASA Astrophysics Data System (ADS)

    Adib, George A.; Sabry, Yasser M.; Khalil, Diaa

    2016-04-01

    Optical filters with relatively large FSR and narrow linewidth are simultaneously needed for different applications. The ratio between the FSR and the 3-dB linewidth is given by finesse of the filter, which is solely determined by the different energy loss mechanisms limited by the technology advancement. In this work, we present a novel coupled-cavity configuration embedding an optical filter and a gain medium; allowing an overall finesse enhancement and simultaneous FSR and 3-dB linewidth engineering beyond the technological limits of the filter fabrication method. The configuration consists of two resonators. An active ring resonator comprises an optical gain medium and a passive resonator. In one configuration, the optical filter is the passive resonator itself. In a second configuration, the passive resonator is another ring resonator that embeds the optical filter. The presented configurations using a semiconductor optical amplifier are applied one time to a mechanically Fabry-Perot filter in the first presented configuration; and a second time to a fiber ring filter in the second presented configuration. The mechanical filter has an original 3-dB linewidth of 1nm and an FSR that is larger than 100nm while the enhanced linewidth is about 0.3nm. The fiber ring filter length is 4 m and directional coupler ratios of 90/10corresponding to a 3-dBlinewidth of about 4MHz and an FSR of 47 MHz. The enhanced 3- dBlinewidth of the overall filter configuration is 200kHz, demonstrating finesse enhancement up to20 times the original finesse of the filter.

  7. Activation in the VTA and Nucleus Accumbens Increases in Anticipation of Both Gains and Losses

    PubMed Central

    Carter, R. McKell; MacInnes, Jeff J.; Huettel, Scott A.; Adcock, R. Alison

    2009-01-01

    To represent value for learning and decision making, the brain must encode information about both the motivational relevance and affective valence of anticipated outcomes. The nucleus accumbens (NAcc) and ventral tegmental area (VTA) are thought to play key roles in representing these and other aspects of valuation. Here, we manipulated the valence (i.e., monetary gain or loss) and personal relevance (i.e., self-directed or charity-directed) of anticipated outcomes within a variant of the monetary incentive delay task. We scanned young-adult participants using functional magnetic resonance imaging (fMRI), utilizing imaging parameters targeted for the NAcc and VTA. For both self-directed and charity-directed trials, activation in the NAcc and VTA increased to anticipated gains, as predicted by prior work, but also increased to anticipated losses. Moreover, the magnitude of responses in both regions was positively correlated for gains and losses, across participants, while an independent reward-sensitivity covariate predicted the relative difference between and gain- and loss-related activation on self-directed trials. These results are inconsistent with the interpretation that these regions reflect anticipation of only positive-valence events. Instead, they indicate that anticipatory activation in reward-related regions largely reflects the motivational relevance of an upcoming event. PMID:19753142

  8. Interleukin-18 activates skeletal muscle AMPK and reduces weight gain and insulin resistance in mice.

    PubMed

    Lindegaard, Birgitte; Matthews, Vance B; Brandt, Claus; Hojman, Pernille; Allen, Tamara L; Estevez, Emma; Watt, Matthew J; Bruce, Clinton R; Mortensen, Ole H; Syberg, Susanne; Rudnicka, Caroline; Abildgaard, Julie; Pilegaard, Henriette; Hidalgo, Juan; Ditlevsen, Susanne; Alsted, Thomas J; Madsen, Andreas N; Pedersen, Bente K; Febbraio, Mark A

    2013-09-01

    Circulating interleukin (IL)-18 is elevated in obesity, but paradoxically causes hypophagia. We hypothesized that IL-18 may attenuate high-fat diet (HFD)-induced insulin resistance by activating AMP-activated protein kinase (AMPK). We studied mice with a global deletion of the α-isoform of the IL-18 receptor (IL-18R(-/-)) fed a standard chow or HFD. We next performed gain-of-function experiments in skeletal muscle, in vitro, ex vivo, and in vivo. We show that IL-18 is implicated in metabolic homeostasis, inflammation, and insulin resistance via mechanisms involving the activation of AMPK in skeletal muscle. IL-18R(-/-) mice display increased weight gain, ectopic lipid deposition, inflammation, and reduced AMPK signaling in skeletal muscle. Treating myotubes or skeletal muscle strips with IL-18 activated AMPK and increased fat oxidation. Moreover, in vivo electroporation of IL-18 into skeletal muscle activated AMPK and concomitantly inhibited HFD-induced weight gain. In summary, IL-18 enhances AMPK signaling and lipid oxidation in skeletal muscle implicating IL-18 in metabolic homeostasis.

  9. Effect of the upper limbs muscles activity on the mechanical energy gain in pole vaulting.

    PubMed

    Frère, Julien; Göpfert, Beat; Slawinski, Jean; Tourny-chollet, Claire

    2012-04-01

    The shoulder muscles are highly solicited in pole vaulting and may afford energy gain. The objective of this study was to determine the bilateral muscle activity of the upper-limbs to explain the actions performed by the vaulter to bend the pole and store elastic energy. Seven experienced athletes performed 5-10 vaults which were recorded using two video cameras (50Hz). The mechanical energy of the centre of gravity (CG) was computed, while surface electromyographic (EMG) profiles were recorded from 5 muscles bilateral: deltoideus, infraspinatus, biceps brachii, triceps, and latissimus dorsi muscles. The level of intensity from EMG profile was retained in four sub phases between take-off (TO1) and complete pole straightening (PS). The athletes had a mean mechanical energy gain of 22% throughout the pole vault, while the intensities of deltoideus, biceps brachii, and latissimus dorsi muscles were sub phases-dependent (p<0.05). Stabilizing the glenohumeral joint (increase of deltoideus and biceps brachii activity) and applying a pole bending torque (increase of latissimus dorsi activity) required specific muscle activation. The gain in mechanical energy of the vaulter could be linked to an increase in muscle activation, especially from latissimusdorsi muscles.

  10. Muscle activity during functional coordination training: implications for strength gain and rehabilitation.

    PubMed

    Jørgensen, Marie B; Andersen, Lars L; Kirk, Niels; Pedersen, Mogens T; Søgaard, Karen; Holtermann, Andreas

    2010-07-01

    The purpose of this study was to evaluate if different types, body positions, and levels of progression of functional coordination exercises can provide sufficiently high levels of muscle activity to improve strength of the neck, shoulder, and trunk muscles. Nine untrained women were familiarized with 7 functional coordination exercises 12 times during 4 weeks before testing. Surface electromyographic (EMG) activity was obtained from rectus abdominus, erector spinae, obliquus externus, and trapezius during the exercises with 2-4 levels of progression. Electromyography was normalized to the maximal EMG activity during maximal voluntary contractions, and a p value < 0.05 was considered significant. All recorded muscles reached sufficiently high levels of activity during the coordination exercises for strength gain (>60% of maximal EMG activity). Type of exercise played a significant role for the attained muscle activity. Body position during the exercises was important for the activity of the erector spinae, and level of progression was important for the activity of the trapezius. The findings indicate that depending on type, body position, and level of progression, functional coordination training can be performed with a muscle activity sufficient for strength gain. Functional coordination training may therefore be a good choice for prevention or rehabilitation of musculoskeletal pain or injury in the neck, shoulder, or trunk muscles.

  11. Representation of potential information gain to measure the price of anarchy on ISR activities

    NASA Astrophysics Data System (ADS)

    Ortiz-Peña, Hector J.; Hirsch, Michael; Karwan, Mark; Nagi, Rakesh; Sudit, Moises

    2013-05-01

    One of the main technical challenges facing intelligence analysts today is effectively determining information gaps from huge amounts of collected data. Moreover, getting the right information to/from the right person (e.g., analyst, warfighter on the edge) at the right time in a distributed environment has been elusive to our military forces. Synchronization of Intelligence, Surveillance, and Reconnaissance (ISR) activities to maximize the efficient utilization of limited resources (both in quantity and capabilities) has become critically important to increase the accuracy and timeliness of overall information gain. Given this reality, we are interested in quantifying the degradation of solution quality (i.e., information gain) as a centralized system synchronizing ISR activities (from information gap identification to information collection and dissemination) moves to a more decentralized framework. This evaluation extends the concept of price of anarchy, a measure of the inefficiency of a system when agents maximize decisions without coordination, by considering different levels of decentralization. Our initial research representing the potential information gain in geospatial and time discretized spaces is presented. This potential information gain map can represent a consolidation of Intelligence Preparation of the Battlefield products as input to automated ISR synchronization tools. Using the coordination of unmanned vehicles (UxVs) as an example, we developed a mathematical programming model for multi-perspective optimization in which each UxV develops its own fight plan to support mission objectives based only on its perspective of the environment (i.e., potential information gain map). Information is only exchanged when UxVs are part of the same communication network.

  12. Pregnant women's perceptions of weight gain, physical activity, and nutrition using Theory of Planned Behavior constructs.

    PubMed

    Whitaker, Kara M; Wilcox, Sara; Liu, Jihong; Blair, Steven N; Pate, Russell R

    2016-02-01

    A better understanding of women's perceptions of weight gain and related behaviors during pregnancy is necessary to inform behavioral interventions. We used the Theory of Planned Behavior (TPB) to examine pregnant women's perceptions and intentions toward weight gain, physical activity (PA), and nutrition using a mixed methods study design. Women between 20 and 30 weeks gestation (n = 189) were recruited to complete an Internet-based survey. Salient beliefs toward weight gain, PA, and nutrition were captured through open-ended responses and content analyzed into themes. TPB constructs (attitude, subjective norm, perceived behavioral control, intentions) were examined using Pearson correlations and hierarchical linear regression models. Salient beliefs were consistent with the existing literature in non-pregnant populations, with the addition of many pregnancy-specific beliefs. TPB constructs accounted for 23-39 % of the variance in weight gain, PA, and nutrition intentions, and made varying contributions across outcomes. The TPB is a useful framework for examining women's weight-related intentions during pregnancy. Study implications for intervention development are discussed.

  13. Light-induced cooling of active medium of CW TEA CO2 laser

    NASA Astrophysics Data System (ADS)

    Azharonok, Viktor V.; Filatova, Irina I.; Shimanovich, Vladimir D.

    2003-10-01

    In the present paper a gas kinetic temperature change of active medium of high-power TEA CO2 laser that is conditioned by a self-influence of laser radiation on plasma parameters, is investigated. The active medium was pumped by a self-sustained transverse glow discharge. The gas kinetic temperature Tg of plasma has been deduced from the half-width of rotationally unresolved spectral bands of the (2+)N2. It is shown that the laser radiation propagation through the inverse medium causes a cooling of the active medium. The degree of the gas mixture cooling δTg~5K at W~2.2 W/2.2 W/cm3 and δTg~60 K at W~4.4 W/cm3. We suppose that the effect of the active medium cooling is connected with the change of a kinetic of V-T relaxation in asymmetrical mode of the active medium cooling is connected with the change of a kinetic of V-T relaxation in asymmetrical mode of the active medium cooling is connected with with the change of a kinetic of V-T relaxation in asymmetrical mode of vibrationally-excited CO2 molecule when the lasing takes place in the laser resonator. Analytical estimation of light-induced temperature change δT*g of fast-flow TEA CO2-laser active medium are compared with the experimental ones.

  14. Preventing weight gain through exercise and physical activity in the elderly: a systematic review.

    PubMed

    Stehr, Mareike D; von Lengerke, Thomas

    2012-05-01

    This review examines the role of exercise and physical activity for preventing weight gain in older people. A structured search using MeSH-vocabulary and Title/Abstract-searches was conducted in PubMed for January 2000 to June 2011, identifying weight gain and exercise or physical activity as study topics, and aged adults as target group. In study selection, all types of exercise and physical activity and any measure of weight change in aged adults (≥65 years) or postmenopausal women were considered. N=9 primary studies were identified. All were conducted in the US, with one study additionally including samples from Canada and the UK. Three studies focused on aged adults, while six concentrated specifically on postmenopausal women. Forms of exercise or physical activity comprised self-reported exercise history in four studies and low, moderate or high intensity exercise interventions in five studies. Four studies combined exercise with a hypocaloric diet and included comparison groups receiving either diet only, health education, stretching or a delayed intervention (one study each). Exercise was associated with weight loss (1.1-6 kg) in all intervention studies, all of which studied an overweight sample, and with weight maintenance in most observational studies, all of which studied a general population or otherwise overweight-unspecific sample. In sum, exercise and physical activity can effectively prevent weight gain in older adults and postmenopausal women either in terms of weight loss or maintenance. They can preserve lean body mass and thus are important for the balance between potentially positive and negative effects of weight reduction in later life. In addition, since all intervention studies were conducted with an overweight sample, it seems that primordial prevention (in terms of preventing the development of risk factors such as excess weight in the first place) might be a neglected issue in geriatric and postmenopausal prevention.

  15. Wakefields Generated by Electron Beams Passing through a Waveguide Loaded with an Active Medium

    SciTech Connect

    Tyukhtin, Andrey; Kanareykin, Alexei; Schoessow, Paul

    2006-11-27

    The wakefields of a relativistic electron beam passing through a waveguide loaded with an active medium with weak resonant dispersion have been considered. For the calculations in this paper the parameters of the medium are those of a solution of fullerene (C60) in a nematic liquid crystal that exhibits activity in the X-band. It was shown that several of the TM accelerating modes can be amplified for the geometries under consideration; structures in which higher order modes are amplified exhibit essential advantages as PASERs. In particular, the amplification of the highest mode occurs in a structure loaded with a rather thick active medium layer that maximizes the energy stored by the active medium.

  16. Individual Differences in Striatum Activity to Food Commercials Predict Weight Gain in Adolescents

    PubMed Central

    Yokum, Sonja; Gearhardt, Ashley N.; Harris, Jennifer L.; Brownell, Kelly D.; Stice, Eric

    2014-01-01

    Objective Adolescents view thousands of food commercials annually, but little is known about how individual differences in neural response to food commercials relate to weight gain. To add to our understanding of individual risk factors for unhealthy weight gain and environmental contributions to the obesity epidemic, we tested the associations between reward region (striatum and orbitofrontal cortex [OFC]) responsivity to food commercials and future change in Body Mass Index (BMI). Design and Methods Adolescents (N = 30) underwent a scan session at baseline while watching a television show edited to include 20 food commercials and 20 non-food commercials. BMI was measured at baseline and 1-year follow-up. Results Activation in the striatum, but not OFC, in response to food commercials relative to non-food commercials and in response to food commercials relative to the television show was positively associated with change in BMI over 1-year follow-up. Baseline BMI did not moderate these effects. Conclusions The results suggest that there are individual differences in neural susceptibility to food advertising. These findings highlight a potential mechanism for the impact of food marketing on adolescent obesity. PMID:25155745

  17. Determinants of Pregnant Women's Online Self-Regulatory Activities for Appropriate Gestational Weight Gain.

    PubMed

    Kim, Hye Kyung; Niederdeppe, Jeff; Guillory, Jamie; Graham, Meredith; Olson, Christine; Gay, Geri

    2015-01-01

    This study examined psychosocial and sociodemographic factors associated with pregnant women's use of Web-based tools to set and monitor personal goals for healthy diet and physical activity. These tools were made available to women participating in a randomized trial testing a Web-based intervention to promote appropriate gestational weight gain. We used data from a baseline survey of pregnant women assigned to the intervention group and log data on women's use of various intervention features (N = 873). Women who believed that appropriate gestational weight gain would lead to healthy outcomes for their child were more likely to engage in online goal-setting and self-monitoring. Less positive outcome expectancy beliefs about the relationship between their own weight and baby's health partially explains why some at risk subpopulations (e.g., African-American women) were less likely to utilize online self-regulatory tools. This study specifies key psychosocial and motivational factors that guide the construction and monitoring of goals among pregnant women. These findings offer guidance for the design of interventions to promote self-regulatory techniques by identifying groups for whom those features are most likely to be useful, as well as psychological determinants of their use.

  18. Development of active porous medium filters based on plasma textiles

    SciTech Connect

    Kuznetsov, Ivan A.; Saveliev, Alexei V.; Rasipuram, Srinivasan; Kuznetsov, Andrey V.; Brown, Alan; Jasper, Warren

    2012-05-15

    Inexpensive, flexible, washable, and durable materials that serve as antimicrobial filters and self-decontaminating fabrics are needed to provide active protection to people in areas regularly exposed to various biohazards, such as hospitals and bio research labs working with pathogens. Airlines and cruise lines need such material to combat the spread of infections. In households these materials can be used in HVAC filters to fight indoor pollution, which is especially dangerous to people suffering from asthma. Efficient filtering materials are also required in areas contaminated by other types of hazardous dust particulates, such as nuclear dust. The primary idea that guided the undertaken study is that a microplasma-generating structure can be embedded in a textile fabric to generate a plasma sheath (''plasma shield'') that kills bacterial agents coming in contact with the fabric. The research resulted in the development of a plasma textile that can be used for producing new types of self-decontaminating garments, fabrics, and filter materials, capable of activating a plasma sheath that would filter, capture, and destroy any bacteriological agent deposited on its surface. This new material relies on the unique antimicrobial and catalytic properties of cold (room temperature) plasma that is benign to people and does not cause thermal damage to many polymer textiles, such as Nomex and polypropylene. The uniqueness of cold plasma as a disinfecting agent lies in the inability of bacteria to develop resistance to plasma exposure, as they can for antibiotics. Plasma textiles could thus be utilized for microbial destruction in active antimicrobial filters (for continuous decontamination and disinfection of large amounts of air) as well as in self-decontaminating surfaces and antibacterial barriers (for example, for creating local antiseptic or sterile environments around wounds and burns).

  19. Development of active porous medium filters based on plasma textiles

    NASA Astrophysics Data System (ADS)

    Kuznetsov, Ivan A.; Saveliev, Alexei V.; Rasipuram, Srinivasan; Kuznetsov, Andrey V.; Brown, Alan; Jasper, Warren

    2012-05-01

    Inexpensive, flexible, washable, and durable materials that serve as antimicrobial filters and self-decontaminating fabrics are needed to provide active protection to people in areas regularly exposed to various biohazards, such as hospitals and bio research labs working with pathogens. Airlines and cruise lines need such material to combat the spread of infections. In households these materials can be used in HVAC filters to fight indoor pollution, which is especially dangerous to people suffering from asthma. Efficient filtering materials are also required in areas contaminated by other types of hazardous dust particulates, such as nuclear dust. The primary idea that guided the undertaken study is that a microplasma-generating structure can be embedded in a textile fabric to generate a plasma sheath ("plasma shield") that kills bacterial agents coming in contact with the fabric. The research resulted in the development of a plasma textile that can be used for producing new types of self-decontaminating garments, fabrics, and filter materials, capable of activating a plasma sheath that would filter, capture, and destroy any bacteriological agent deposited on its surface. This new material relies on the unique antimicrobial and catalytic properties of cold (room temperature) plasma that is benign to people and does not cause thermal damage to many polymer textiles, such as Nomex and polypropylene. The uniqueness of cold plasma as a disinfecting agent lies in the inability of bacteria to develop resistance to plasma exposure, as they can for antibiotics. Plasma textiles could thus be utilized for microbial destruction in active antimicrobial filters (for continuous decontamination and disinfection of large amounts of air) as well as in self-decontaminating surfaces and antibacterial barriers (for example, for creating local antiseptic or sterile environments around wounds and burns).

  20. Zeno inhibition of polarization rotation in an optically active medium

    NASA Astrophysics Data System (ADS)

    Gonzalo, Isabel; Porras, Miguel A.; Luis, Alfredo

    2015-07-01

    We describe an experiment in which the rotation of the polarization of light propagating in an optically active water solution of D-fructose tends to be inhibited by frequent monitoring whether the polarization remains unchanged. This is an example of the Zeno effect that has remarkable pedagogical interest because of its conceptual simplicity, easy implementation, low cost, and because the same the Zeno effect holds at classical and quantum levels. An added value is the demonstration of the Zeno effect beyond typical idealized assumptions in a practical setting with real polarizers.

  1. Differential Classical Conditioning Selectively Heightens Response Gain of Neural Population Activity in Human Visual Cortex

    PubMed Central

    Song, Inkyung; Keil, Andreas

    2015-01-01

    Neutral cues, after being reliably paired with noxious events, prompt defensive engagement and amplified sensory responses. To examine the neurophysiology underlying these adaptive changes, we quantified the contrast-response function of visual cortical population activity during differential aversive conditioning. Steady-state visual evoked potentials (ssVEPs) were recorded while participants discriminated the orientation of rapidly flickering grating stimuli. During each trial, luminance contrast of the gratings was slowly increased and then decreased. Right-tilted gratings (CS+) were paired with loud white noise but left-tilted gratings (CS−) were not. The contrast-following waveform envelope of ssVEPs showed selective amplification of the CS+ only during the high-contrast stage of the viewing epoch. Findings support the notion that motivational relevance, learned in a time frame of minutes, affects vision through a response gain mechanism. PMID:24981277

  2. Lossless Airy Surface Polaritons in a Metamaterial via Active Raman Gain

    PubMed Central

    Zhang, Qi; Tan, Chaohua; Huang, Guoxiang

    2016-01-01

    We propose a scheme to realize a lossless propagation of linear and nonlinear Airy surface polaritons (SPs) via active Raman gain (ARG). The system we suggest is a planar interface superposed by a negative index metamaterial (NIMM) and a dielectric, where three-level quantum emitters are doped. By using the ARG from the quantum emitters and the destructive interference effect between the electric and magnetic responses from the NIMM, we show that not only the Ohmic loss of the NIMM but also the light absorption of the quantum emitters can be completely eliminated. As a result, non-diffractive Airy SPs may propagate for very long distance without attenuation. We also show that the Kerr nonlinearity of the system can be largely enhanced due to the introduction of the quantum emitters and hence lossless Airy surface polaritonic solitons with very low power can be generated in the system. PMID:26891795

  3. Tumor-selective mitochondrial network collapse induced by atmospheric gas plasma-activated medium.

    PubMed

    Saito, Kosuke; Asai, Tomohiko; Fujiwara, Kyoko; Sahara, Junki; Koguchi, Haruhisa; Fukuda, Noboru; Suzuki-Karasaki, Miki; Soma, Masayoshi; Suzuki-Karasaki, Yoshihiro

    2016-04-12

    Non-thermal atmospheric gas plasma (AGP) exhibits cytotoxicity against malignant cells with minimal cytotoxicity toward normal cells. However, the mechanisms of its tumor-selective cytotoxicity remain unclear. Here we report that AGP-activated medium increases caspase-independent cell death and mitochondrial network collapse in a panel of human cancer cells, but not in non-transformed cells. AGP irradiation stimulated reactive oxygen species (ROS) generation in AGP-activated medium, and in turn the resulting stable ROS, most likely hydrogen peroxide (H2O2), activated intracellular ROS generation and mitochondrial ROS (mROS) accumulation. Culture in AGP-activated medium resulted in cell death and excessive mitochondrial fragmentation and clustering, and these responses were inhibited by ROS scavengers. AGP-activated medium also increased dynamin-related protein 1-dependent mitochondrial fission in a tumor-specific manner, and H2O2 administration showed similar effects. Moreover, the vulnerability of tumor cells to mitochondrial network collapse appeared to result from their higher sensitivity to mROS accumulation induced by AGP-activated medium or H2O2. The present findings expand our previous observations on death receptor-mediated tumor-selective cell killing and reinforce the importance of mitochondrial network remodeling as a powerful target for tumor-selective cancer treatment.

  4. Chemically defined medium enhances bioelectric activity in mouse spinal cord-dorsal root ganglion cultures.

    PubMed

    Habets, A M; Baker, R E; Brenner, E; Romijn, H J

    1981-02-23

    Co-cultures of mouse spinal cord with dorsal root ganglion (DRG) cultures were grown either in horse serum (HS)-supplemented medium or in a serum-free, chemically defined medium (CDM). The cytoarchitecture of cord--DRG explants was fully retained in CDM, with little or no distortion due to flattening of the explant, as is invariably observed in HS-supplemented cultures. Functional properties such as bioelectric activity and DRG--spinal cord interconnectivity were well sustained in CDM.

  5. Association of Proton Pump Inhibitor (PPI) Use with Energy Intake, Physical Activity, and Weight Gain

    PubMed Central

    Czwornog, Jennifer L.; Austin, Gregory L.

    2015-01-01

    Studies suggest proton pump inhibitor (PPI) use impacts body weight regulation, though the effect of PPIs on energy intake, energy extraction, and energy expenditure is unknown. We used data on 3073 eligible adults from the National Health and Nutrition Examination Survey (NHANES). Medication use, energy intake, diet composition, and physical activity were extracted from NHANES. Multivariate regression models included confounding variables. Daily energy intake was similar between PPI users and non-users (p = 0.41). Diet composition was similar between the two groups, except that PPI users consumed a slightly greater proportion of calories from fat (34.5% vs. 33.2%; p = 0.02). PPI users rated themselves as being as physically active as their age/gender-matched peers and reported similar frequencies of walking or biking. However, PPI users were less likely to have participated in muscle-strengthening activities (OR: 0.53; 95% CI: 0.30–0.95). PPI users reported similar sedentary behaviors to non-users. Male PPI users had an increase in weight (of 1.52 ± 0.59 kg; p = 0.021) over the previous year compared to non-users, while female PPI users had a non-significant increase in weight. The potential mechanisms for PPI-associated weight gain are unclear as we did not find evidence for significant differences in energy intake or markers of energy expenditure. PMID:26492268

  6. High resolution ALMA observations of dense molecular medium in the central regions of active galaxies

    NASA Astrophysics Data System (ADS)

    Kohno, Kotaro

    2015-08-01

    I will present recent ALMA results on the dense molecular gas in the central regions of local active galaxies, including NGC 1068, NGC 1097, and NGC 7469, hosting both AGN and circumnuclear starburst regions. Impact of X-ray radiation, outflows, and shocks from active nuclei on the physical and chemical properties of the surrouding dense molecular medium will be discussed.

  7. Dehydrated Hereditary Stomatocytosislinked to gain-of-function mutations in mechanically activated PIEZO1 ion channels

    PubMed Central

    Albuisson, Juliette; Murthy, Swetha E.; Bandell, Michael; Coste, Bertrand; Louis-dit-Picard, Hélène; Mathur, Jayanti; Fénéant-Thibault, Madeleine; Tertian, Gérard; de Jaureguiberry, Jean-Pierre; Syfuss, Pierre-Yves; Cahalan, Stuart; Garçon, Loic; Toutain, Fabienne; Rohrlich, Pierre Simon; Delaunay, Jean; Picard, Véronique; Jeunemaitre, Xavier; Patapoutian, Ardem

    2013-01-01

    Dehydrated hereditary stomatocytosis (DHS) is a genetic condition with defective red blood cell (RBC) membrane properties that causes an imbalance in intracellular cation concentrations. Recently, two missense mutations inthe mechanically activated PIEZO1(FAM38A) ion channel were associated with DHS. However, it is not known how these mutations affect PIEZO1 function. Here, by combining linkage analysis and whole-exome sequencing in a large pedigree and Sanger sequencing in two additional kindreds and 11 unrelated DHS cases, we identifythree novel missense mutations and one recurrent duplication in PIEZO1, demonstrating that it is the major gene for DHS. All the DHS-associated mutations locate at C-terminal half of PIEZO1. Remarkably, we find that all PIEZO1 mutations give rise to mechanically activated currents that inactivate more slowly than wild-type currents. This gain-of-function PIEZO1 phenotype provides insight that helps to explain the increased permeability of cations in RBCs of DHS patients. Our findings also suggest a new role for mechanotransduction in RBC biology and pathophysiology. PMID:23695678

  8. Evaluation of the effects of a plasma activated medium on cancer cells

    NASA Astrophysics Data System (ADS)

    Mohades, S.; Laroussi, M.; Sears, J.; Barekzi, N.; Razavi, H.

    2015-12-01

    The interaction of low temperature plasma with liquids is a relevant topic of study to the field of plasma medicine. This is because cells and tissues are normally surrounded or covered by biological fluids. Therefore, the chemistry induced by the plasma in the aqueous state becomes crucial and usually dictates the biological outcomes. This process became even more important after the discovery that plasma activated media can be useful in killing various cancer cell lines. Here, we report on the measurements of concentrations of hydrogen peroxide, a species known to have strong biological effects, produced by application of plasma to a minimum essential culture medium. The activated medium is then used to treat SCaBER cancer cells. Results indicate that the plasma activated medium can kill the cancer cells in a dose dependent manner, retain its killing effect for several hours, and is as effective as apoptosis inducing drugs.

  9. Evaluation of the effects of a plasma activated medium on cancer cells

    SciTech Connect

    Mohades, S.; Laroussi, M. Sears, J.; Barekzi, N.; Razavi, H.

    2015-12-15

    The interaction of low temperature plasma with liquids is a relevant topic of study to the field of plasma medicine. This is because cells and tissues are normally surrounded or covered by biological fluids. Therefore, the chemistry induced by the plasma in the aqueous state becomes crucial and usually dictates the biological outcomes. This process became even more important after the discovery that plasma activated media can be useful in killing various cancer cell lines. Here, we report on the measurements of concentrations of hydrogen peroxide, a species known to have strong biological effects, produced by application of plasma to a minimum essential culture medium. The activated medium is then used to treat SCaBER cancer cells. Results indicate that the plasma activated medium can kill the cancer cells in a dose dependent manner, retain its killing effect for several hours, and is as effective as apoptosis inducing drugs.

  10. Active-medium inhomogeneities and optical quality of radiation of supersonic chemical oxygen-iodine lasers

    SciTech Connect

    Boreysho, A S; Druzhinin, S L; Lobachev, V V; Savin, A V; Strakhov, S Yu; Trilis, A V

    2007-09-30

    Optical inhomogeneities of the active medium of a supersonic chemical oxygen-iodine laser (COIL) and their effect on the radiation parameters are studied in the case when an unstable resonator is used. Classification of optical inhomogeneities and the main factors affecting the quality of COIL radiation are considered. The results of numerical simulation of a three-dimensional gas-dynamic active medium and an unstable optical resonator in the diffraction approximation are presented. The constraints in the fabrication of large-scale COILs associated with a deterioration of the optical quality of radiation are determined. (lasers)

  11. Gas dynamics of the active medium of a supersonic cw HF chemical laser

    SciTech Connect

    Fedorov, Igor' A; Rotinyan, Mikhail A; Krivitskii, A M

    2000-12-31

    Gas-dynamic characteristics of a 5-kW supersonic cw HF chemical laser with a nozzle array of size 25 cm x 2.8 cm and the nozzle - nozzle mixing scheme were experimentally studied. The distributions of Mach numbers, static pressure, total pressure behind the normal shock, and the loss of total pressure were measured in the flow of an active medium in wide ranges of variation of the flow rate of secondary fuel (hydrogen) and pressure in the atomic-fluorine generator. The energy parameters of the laser were found to be interrelated with the gas dynamics and the optical quality of the active laser medium. (lasers)

  12. Deep saturation of a Cerenkov wakefield amplified by an active medium

    NASA Astrophysics Data System (ADS)

    Toroker, Z.; Schächter, L.

    2015-07-01

    A trigger bunch of electrons traveling inside or in the vicinity of a dielectric medium generates a Cerenkov wake. If the dielectric medium is active, a small fraction of the spectrum of the wake is amplified and far behind the trigger bunch where the active medium is fully depleted, the amplitude and the phase of the wake are virtually constant. In this range, a second bunch of electrons trailing behind the trigger bunch can be accelerated. For optimal operation, the trigger bunch should be density modulated at the resonant frequency of the medium. However, we demonstrate that even if the bunch is uniform along many wavelengths we may still take advantage of the saturation characteristics to obtain conditions adequate for acceleration. Further we demonstrate that for large enough number of electrons it is possible to have a coherent amplified wake after a saturation length which is determined analytically and tested numerically. In addition, we show that almost 100% of the stored energy in the active medium can be transferred to the acceleration of the trailing bunch electrons. The relatively large energy spread due to the beam loading is well suited to a medical accelerator. When the beam loading is weak, the gradient is virtually constant but the acceleration efficiency drops to about 2% for typical parameters.

  13. Sensitivity- and effort-gain analysis: multilead ECG electrode array selection for activation time imaging.

    PubMed

    Hintermüller, Christoph; Seger, Michael; Pfeifer, Bernhard; Fischer, Gerald; Modre, Robert; Tilg, Bernhard

    2006-10-01

    Methods for noninvasive imaging of electric function of the heart might become clinical standard procedure the next years. Thus, the overall procedure has to meet clinical requirements as an easy and fast application. In this paper, we propose a new electrode array which improves the resolution of methods for activation time imaging considering clinical constraints such as easy to apply and compatibility with routine leads. For identifying the body-surface regions where the body surface potential (BSP) is most sensitive to changes in transmembrane potential (TMP), a virtual array method was used to compute local linear dependency (LLD) maps. The virtual array method computes a measure for the LLD in every point on the body surface. The most suitable number and position of the electrodes within the sensitive body surface regions was selected by constructing effort gain (EG) plots. Such a plot depicts the relative attainable rank of the leadfield matrix in relation to the increase in number of electrodes required to build the electrode array. The attainable rank itself was computed by a detector criterion. Such a criterion estimates the maximum number of source space eigenvectors not covered by noise when being mapped to the electrode space by the leadfield matrix and recorded by a detector. From the sensitivity maps, we found that the BSP is most sensitive to changes in TMP on the upper left frontal and dorsal body surface. These sensitive regions are covered best by an electrode array consisting of two L-shaped parts of approximately 30 cm x 30 cm and approximately 20 cm x 20 cm. The EG analysis revealed that the array meeting clinical requirements best and improving the resolution of activation time imaging consists of 125 electrodes with a regular horizontal and vertical spacing of 2-3 cm.

  14. Efficiency of an unstable resonator with an active medium containing small-scale phase inhomogeneities

    SciTech Connect

    Lobachev, V V; Strakhov, S Yu

    2004-01-31

    Properties of an unstable resonator with small-scale periodic inhomogeneities of the refractive index in an active medium are considered. It is shown that the parameters of output radiation depend on the structure of a phase inhomogeneity. The methods for increasing the resonator efficiency are analysed. (resonators. interferometers)

  15. Continuous cultivation of Arthrospira platensis using exhausted medium treated with granular activated carbon

    NASA Astrophysics Data System (ADS)

    Morocho-Jácome, Ana Lucía; Mascioli, Guilherme Favaro; Sato, Sunao; Carvalho, João Carlos Monteiro de

    2015-03-01

    Reusing culture medium of Arthrospira platensis is quite important in large scale production because its inappropriate disposal could exacerbate problems of environmental pollution. This study evaluates the suitability of using different quantities of exhausted Schlösser medium after continuous treatment using granular activated carbon (GAC) with a residence time (T) of 2 h for A. platensis growth in continuous cultivation. A tubular photobioreactor (PBR) and urea as cheap nitrogen source were used, taking as response variables kinetic parameters and biomass composition. The removal of both organic matter and pigment (OMR and PgR, respectively) was measured to evaluate the efficiency of the treatment process. This treatment process yielded high values of OMR (73.7 ± 0.1%) and PgR (52.4 ± 0.4%) using 75% treated medium, thereby A. platensis biomass with high protein content (42.0 ± 0.6%), 1568 ± 15 mg/L cell concentration under steady-state conditions and 941 mg/L d cell productivity. This alternative to simultaneous treatment with GAC for reuse of Schlösser medium in continuous cultivation could ensure no diminution in either cell productivity or protein content in A. platensis cultivation using tubular PBR with 65% reduction in medium culture costs.

  16. Gaining A Geological Perspective Through Active Learning in the Large Lecture Classroom

    NASA Astrophysics Data System (ADS)

    Kapp, J. L.; Richardson, R. M.; Slater, S. J.

    2008-12-01

    NATS 101 A Geological Perspective is a general education course taken by non science majors. We offer 600 seats per semester, with four large lecture sections taught by different faculty members. In the past we have offered optional once a week study groups taught by graduate teaching assistants. Students often feel overwhelmed by the science and associated jargon, and many are prone to skipping lectures altogether. Optional study groups are only attended by ~50% of the students. Faculty members find the class to be a lot of work, mainly due to the grading it generates. Activities given in lecture are often short multiple choice or true false assignments, limiting the depth of understanding we can evaluate. Our students often lack math and critical thinking skills, and we spend a lot of time in lecture reintroducing ideas students should have already gotten from the text. In summer 2007 we were funded to redesign the course. Our goals were to 1) cut the cost of running the course, and 2) improve student learning. Under our redesign optional study groups were replaced by once a week mandatory break out sessions where students complete activities that have been introduced in lecture. Break out sessions substitute for one hour of lecture, and are run by undergraduate preceptors and graduate teaching assistants (GTAs). During the lecture period, lectures themselves are brief with a large portion of the class devoted to active learning in small groups. Weekly reading quizzes are submitted via the online course management system. Break out sessions allow students to spend more time interacting with their fellow students, undergraduate preceptors, and GTAs. They get one on one help in break out sessions on assignments designed to enhance the lecture material. The active lecture format means less of their time is devoted to listening passively to a lecture, and more time is spent peer learning an interacting with the instructor. Completing quizzes online allows students

  17. Gain-of-function Mutations in Transient Receptor Potential C6 (TRPC6) Activate Extracellular Signal-regulated Kinases 1/2 (ERK1/2)*

    PubMed Central

    Chiluiza, David; Krishna, Sneha; Schumacher, Valérie A.; Schlöndorff, Johannes

    2013-01-01

    Gain-of-function mutations in the canonical transient receptor potential 6 (TRPC6) gene are a cause of autosomal dominant focal segmental glomerulosclerosis (FSGS). The mechanisms whereby abnormal TRPC6 activity results in proteinuria remain unknown. The ERK1/2 MAPKs are activated in glomeruli and podocytes in several proteinuric disease models. We therefore examined whether FSGS-associated mutations in TRPC6 result in activation of these kinases. In 293T cells and cultured podocytes, overexpression of gain-of-function TRPC6 mutants resulted in increased ERK1/2 phosphorylation, an effect dependent upon channel function. Pharmacologic inhibitor studies implicated several signaling mediators, including calmodulin and calcineurin, supporting the importance of TRPC6-mediated calcium influx in this process. Through medium transfer experiments, we uncovered two distinct mechanisms for ERK activation by mutant TRPC6, a cell-autonomous, EGF receptor-independent mechanism and a non-cell-autonomous mechanism involving metalloprotease-mediated release of a presumed EGF receptor ligand. The inhibitors KN-92 and H89 were able to block both pathways in mutant TRPC6 expressing cells as well as the prolonged elevation of intracellular calcium levels upon carbachol stimulation seen in these cells. However, these effects appear to be independent of their effects on calcium/calmodulin-dependent protein kinase II and PKA, respectively. Phosphorylation of Thr-70, Ser-282, and Tyr-31/285 were not necessary for ERK activation by mutant TRPC6, although a phosphomimetic TRPC6 S282E mutant was capable of ERK activation. Taken together, these results identify two pathways downstream of mutant TRPC6 leading to ERK activation that may play a role in the development of FSGS. PMID:23645677

  18. Neutron-induced nucleation inside bubble chambers using Freon 115 as the active medium

    NASA Astrophysics Data System (ADS)

    Ghilea, M. C.; Meyerhofer, D. D.; Sangster, T. C.

    2011-08-01

    Neutron imaging is used in inertial confinement fusion (ICF) experiments to measure the core symmetry of imploded targets. Liquid bubble chambers have the potential to obtain higher resolution images of the targets for a shorter source-target distance than typical scintillator arrays. Due to the fact that nucleation models used in gel detectors research cannot always give correct estimates for the neutron-induced bubble density inside a liquid bubble chamber, an improved theoretical model to describe the mechanism of bubble formation for Freon 115 as the active medium has been developed. It shows that the size of the critical radius for the nucleation process determines the mechanism of bubble formation and the sensitivity of the active medium to the 14.1-MeV incident neutrons resulting from ICF implosions. The bubble-growth mechanism is driven by the excitation of the medium electronic levels and not by electrons ejected from the medium's atoms as happens for the bubble chambers used to detect charged particles. The model accurately predicts the neutron-induced bubble density measured on OMEGA with both liquid bubble chambers and gel detectors.

  19. The Effects of Activity and Gain Based Virtual Material on Student's Success, Permanency and Attitudes towards Science Lesson

    ERIC Educational Resources Information Center

    Tas, Erol

    2015-01-01

    The main objective of this study is to research the effects of a student gains and activity based virtual material on students' success, permanence and attitudes towards science lesson, developed for science and technology lesson 6th grade "Systems in our body" unit. The study, which had a quasi-experimental design, was conducted with…

  20. Steps Ahead: Adaptation of physical activity and dietary guidelines for reducing unhealthy weight gain in the Lower Misissippi Delta

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The purpose of our study was to test the effectiveness of adapting the Dietary Guidelines for Americans (2010) (DG), with and without a physical activity (PA) component, in reducing weight gain in the Lower Mississippi Delta region (LMD) of the United States. A sample of 121 White and African-Americ...

  1. 78 FR 74125 - Agency Information Collection Activities; Comment Request; Measuring Educational Gain in the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-10

    ... Reporting System for Adult Education AGENCY: Department of Education (ED), Office of Vocational and Adult... of Collection: Measuring Educational Gain in the National Reporting System for Adult Education. OMB... (NRS) for adult education. This information is used by the Secretary to determine the suitability...

  2. Evaluation of antimicrobial activity of probiotic bacteria against Salmonella enterica subsp. enterica serovar typhimurium 1344 in a common medium under different environmental conditions.

    PubMed

    Marianelli, Cinzia; Cifani, Noemi; Pasquali, Paolo

    2010-10-01

    The importance of probiotics in human nutrition has been gaining recognition in recent years. These organisms have been shown to promote human health by enhancing immunological and digestive functions and fighting respiratory tract infections. We propose an improved in vitro model for the study of probiotic antimicrobial activity against enteropathogens, by attempting to re-create, in a common culture medium, environmental growth conditions comparable to those present in the small intestine. A preliminary experiment was carried out in order to find a culture medium able to support both probiotics and pathogens. This was done with the aim of obtaining correct assessment of the interaction under shared growth conditions. BHI medium was selected as the common culture medium and was therefore used in antimicrobial activity assays. The interactions between Salmonella 1344 and Lactobacillus rhamnosus and Lactobacillus reuteri were then assessed at different pH and oxygen availability conditions mimicking the small intestinal environment. L. rhamnosus GG ATCC 53103 (LGG) had the strongest antimicrobial effect, in particular under anaerobic conditions and at lower pH levels. Its antagonistic activity involved both lactic acid and secreted non-lactic acid molecules. Our findings suggest that each probiotic strain has an optimum range of action and should therefore be thoroughly investigated to optimize its use.

  3. Risperidone-induced weight gain and reduced locomotor activity in juvenile female rats: The role of histaminergic and NPY pathways.

    PubMed

    Lian, Jiamei; De Santis, Michael; He, Meng; Deng, Chao

    2015-01-01

    Second generation antipsychotic drugs (SGAs) such as risperidone are increasingly prescribed (mostly for off-label use) to children and adolescents for treating various mental disorders. SGAs cause serious weight gain/obesity and other metabolic side-effects. This study aimed to establish an animal model of risperidone-induced weight gain in female juvenile rats, and to investigate the effects of risperidone on the expression of hypothalamic histaminergic H1 receptors (H1R) and neuropeptides, and their association with weight gain. Female Sprague Dawley rats were treated orally with risperidone (0.3mg/kg, 3 times/day) or vehicle (control) starting from postnatal day (PD) 23 (±1 day) for 3 weeks (a period corresponding to the childhood-adolescent period in humans). In the female juvenile rats, risperidone treatment increased food intake and body weight gain, which started to appear after 12 days' treatment. Risperidone also significantly decreased the locomotor activity of the female rats. Consistently, risperidone significantly elevated mRNA expression of hypothalamic H1R, neuropeptide Y (NPY), and agouti-related peptide (AgRP) compared to controls, and H1R and NPY levels were correlated with risperidone enhanced weight gain and food intake in the female juvenile rats. However, risperidone did not affect hypothalamic proopiomelanocortin (POMC) and cocaine- and amphetamine-regulated transcript (CART) mRNA expression. Therefore, these results suggested that risperidone elevated appetite and body weight gain in juveniles via regulation of the hypothalamic H1R, NPY and AgRP pathways, as well as by reducing activity.

  4. Conditioned medium from alternatively activated macrophages induce mesangial cell apoptosis via the effect of Fas

    SciTech Connect

    Huang, Yuan; Luo, Fangjun; Li, Hui; Jiang, Tao; Zhang, Nong

    2013-11-15

    During inflammation in the glomerulus, the proliferation of myofiroblast-like mesangial cells is commonly associated with the pathological process. Macrophages play an important role in regulating the growth of resident mesangial cells in the glomeruli. Alternatively activated macrophage (M2 macrophage) is a subset of macrophages induced by IL-13/IL-4, which is shown to play a repair role in glomerulonephritis. Prompted by studies of development, we performed bone marrow derived macrophage and rat mesangial cell co-culture study. Conditioned medium from IL-4 primed M2 macrophages induced rat mesangial cell apoptosis. The pro-apoptotic effect of M2 macrophages was demonstrated by condensed nuclei stained with Hoechst 33258, increased apoptosis rates by flow cytometry analysis and enhanced caspase-3 activation by western blot. Fas protein was up-regulated in rat mesangial cells, and its neutralizing antibody ZB4 partly inhibited M2 macrophage-induced apoptosis. The up-regulated arginase-1 expression in M2 macrophage also contributed to this apoptotic effect. These results indicated that the process of apoptosis triggered by conditioned medium from M2 macrophages, at least is partly conducted through Fas in rat mesangial cells. Our findings provide compelling evidence that M2 macrophages control the growth of mesangial cells in renal inflammatory conditions. - Highlights: • Conditioned-medium from M2 macrophages induces rat mesangial cell (MsC) apoptosis. • M2 macrophage conditioned medium exerts its pro-apoptotic effects via Fas ligand. • Arginase-1 activity in M2 macrophages plays a role in inducing apoptosis in rat MsC.

  5. Electrochemical assay of α-glucosidase activity and the inhibitor screening in cell medium.

    PubMed

    Zhang, Juan; Liu, Ying; Wang, Xiaonan; Chen, Yangyang; Li, Genxi

    2015-12-15

    An electrochemical method is established in this work for the assay of α-glucosidase activity and the inhibitor screening through one-step displacement reaction, which can be directly used in cell medium. The displacement reaction can be achieved via strong binding of 4-aminophenyl-α-D-glucopyranoside (pAPG)/magnetic nanoparticles (MNPs) to pyrene boric acid (PBA) immobilized on the surface of graphite electrode (GE), compared to that of dopamine (DA)/sliver nanoparticles (AgNPs). Since α-glucosidase can specifically catalyze MNPs/pAPG into MNPs/pAP which has no binding capacity with PBA, the activity of both isolated and membrane bound enzyme can be well evaluated by using this proposed method. Meanwhile, signal amplification can be accomplished via the immobilization of DA at the outer layer of AgNPs, and the accuracy can be strengthened through magnetic separation. Moreover, this method can also be utilized for inhibitor screening not only in the medium containing the enzyme but also in cell medium. With good precision and accuracy, it may be extended to other proteases and their inhibitors as well. PMID:26201984

  6. Longevity improvement of optically activated, high gain GaAs photoconductive semiconductor switches

    SciTech Connect

    MAR,ALAN; LOUBRIEL,GUILLERMO M.; ZUTAVERN,FRED J.; O'MALLEY,MARTIN W.; HELGESON,WESLEY D.; BROWN,DARWIN JAMES; HJALMARSON,HAROLD P.; BACA,ALBERT G.

    2000-03-02

    The longevity of high gain GaAs photoconductive semiconductor switches (PCSS) has been extended to over 100 million pulses at 23A, and over 100 pulses at 1kA. This is achieved by improving the ohmic contacts by doping the semi-insulating GaAs underneath the metal, and by achieving a more uniform distribution of contact wear across the entire switch by distributing the trigger light to form multiple filaments. This paper will compare various approaches to doping the contacts, including ion implantation, thermal diffusion, and epitaxial growth. The device characterization also includes examination of the filament behavior using open-shutter, infra-red imaging during high gain switching. These techniques provide information on the filament carrier densities as well as the influence that the different contact structures and trigger light distributions have on the distribution of the current in the devices. This information is guiding the continuing refinement of contact structures and geometries for further improvements in switch longevity.

  7. Effect of the solution temperature in a singlet-oxygen generator on the formation of active medium in an ejector oxygen - iodine laser

    SciTech Connect

    Zagidullin, M V; Nikolaev, V D; Svistun, M I; Khvatov, N A; Palina, N Yu

    2002-02-28

    The influence of the solution temperature in a singlet-oxygen generator on the formation of the active medium in the ejector oxygen - iodine laser is investigated. The following parameters of the active medium at the solution temperature -20{sup 0}C are obtained: the gain is 7.2 x 10{sup -3} cm{sup -1}, the Mach number is M=2, the temperature is 205 K, and the static pressure is 9.3 mmHg. As the solution temperature is increased to -4{sup 0}C, the gain decreases to 5 x 10{sup 3} cm{sup -1}, the Mach number decreases to 1.78, while the temperature and the static pressure increase to 241 K and 10.7 mmHg, respectively. As the solution temperature increases from -20 to -4{sup 0}C, the losses in O{sub 2}({sup 1}{Delta}) increase by less than 20%, while the dissociation efficiency of molecular iodine decreases by less than 21%. (lasers, active media)

  8. Signal transducer and activator of transcription 1 (STAT1) gain-of-function mutations and disseminated coccidioidomycosis and histoplasmosis

    PubMed Central

    Sampaio, Elizabeth P.; Hsu, Amy P.; Pechacek, Joseph; Bax, Hannelore I.; Dias, Dalton L.; Paulson, Michelle L.; Chandrasekaran, Prabha; Rosen, Lindsey B.; Carvalho, Daniel S.; Ding, Li; Vinh, Donald C.; Browne, Sarah K.; Datta, Shrimati; Milner, Joshua D.; Kuhns, Douglas B.; Long Priel, Debra A.; Sadat, Mohammed A.; Shiloh, Michael; De Marco, Brendan; Alvares, Michael; Gillman, Jason W.; Ramarathnam, Vivek; de la Morena, Maite; Bezrodnik, Liliana; Moreira, Ileana; Uzel, Gulbu; Johnson, Daniel; Spalding, Christine; Zerbe, Christa S.; Wiley, Henry; Greenberg, David E.; Hoover, Susan E.; Rosenzweig, Sergio D.; Galgiani, John N.; Holland, Steven M.

    2013-01-01

    Background Impaired signaling in the IFN-γ/IL-12 pathway causes susceptibility to severe disseminated infections with mycobacteria and dimorphic yeasts. Dominant gain-of-function mutations in signal transducer and activator of transcription 1 (STAT1) have been associated with chronic mucocutaneous candidiasis. Objective We sought to identify the molecular defect in patients with disseminated dimorphic yeast infections. Methods PBMCs, EBV-transformed B cells, and transfected U3A cell lines were studied for IFN-γ/IL-12 pathway function. STAT1 was sequenced in probands and available relatives. Interferon-induced STAT1 phosphorylation, transcriptional responses, protein-protein interactions, target gene activation, and function were investigated. Results We identified 5 patients with disseminated Coccidioides immitis or Histoplasma capsulatum with heterozygous missense mutations in the STAT1 coiled-coil or DNA-binding domains. These are dominant gain-of-function mutations causing enhanced STAT1 phosphorylation, delayed dephosphorylation, enhanced DNA binding and transactivation, and enhanced interaction with protein inhibitor of activated STAT1. The mutations caused enhanced IFN-γ–induced gene expression, but we found impaired responses to IFN-γ restimulation. Conclusion Gain-of-function mutations in STAT1 predispose to invasive, severe, disseminated dimorphic yeast infections, likely through aberrant regulation of IFN-γ–mediated inflammation. PMID:23541320

  9. Pregnant women’s perceptions of weight gain, physical activity, and nutrition using Theory of Planned Behavior constructs

    PubMed Central

    Wilcox, Sara; Liu, Jihong; Blair, Steven N.; Pate, Russell R.

    2016-01-01

    A better understanding of women’s perceptions of weight gain and related behaviors during pregnancy is necessary to inform behavioral interventions. We used the Theory of Planned Behavior (TPB) to examine pregnant women’s perceptions and intentions toward weight gain, physical activity (PA), and nutrition using a mixed methods study design. Women between 20 and 30 weeks gestation (n = 189) were recruited to complete an Internet-based survey. Salient beliefs toward weight gain, PA, and nutrition were captured through open-ended responses and content analyzed into themes. TPB constructs (attitude, subjective norm, perceived behavioral control, intentions) were examined using Pearson correlations and hierarchical linear regression models. Salient beliefs were consistent with the existing literature in non-pregnant populations, with the addition of many pregnancy-specific beliefs. TPB constructs accounted for 23–39 % of the variance in weight gain, PA, and nutrition intentions, and made varying contributions across outcomes. The TPB is a useful framework for examining women’s weight-related intentions during pregnancy. Study implications for intervention development are discussed. PMID:26335313

  10. Causes of reduced survival of neonatal pigs by medium-chain triglycerides: blood metabolite and behavioral activity approaches.

    PubMed

    Lin, C L; Chiang, S H; Lee, H F

    1995-07-01

    Two experiments were conducted to investigate the causes of the failure of orally dosed medium-chain triglycerides (MCT) in improving the survival of neonatal pigs. In Exp. 1, four litters consisting of 24 unsuckled neonatal pigs were either dosed with 6 mL/kg BW.75 of MCT or the dosing process was mimicked by inserting and withdrawing the feeding tube at 10 and 18 h after birth. Blood beta-hydroxybutyrate concentration was increased (P < .06) and the depletion of liver glycogen was reduced (P < .05) by MCT. Plasma octanoate (C8) concentration peaked at 1 h and was minimized at 4 to 8 h after each MCT dosage; decanoate (C10) concentration increased (P < .001) gradually after each dosage. Activity of pigs was decreased (P < .01) by MCT. In Exp. 2, 94 litters consisting of 887 neonatal pigs were dosed with either 6 mL/kg BW.75 of MCT, coconut oil (CO), or saline at 10 to 14 and 20 to 28 h after birth. Milk intake (P < .05) and weight gain were reduced (P < .01) in 1- to 2-d-old pigs dosed with MCT compared with intake and gain of pigs dosed with saline. Mortality of large pigs (> 1 kg) was increased (P < .05) but mortality of small pigs (< 1 kg) was not affected by MCT. Mortality of small pigs was reduced (P < .05) but mortality of large pigs (> 1 kg) was not affected by CO. Standing, walking, and suckling behaviors of pigs were not affected by MCT or CO. Coma was evident in 9.7% of pigs dosed with MCT.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7592086

  11. Method and system for edge cladding of laser gain media

    SciTech Connect

    Bayramian, Andrew James; Caird, John Allyn; Schaffers, Kathleen Irene

    2014-03-25

    A gain medium operable to amplify light at a gain wavelength and having reduced transverse ASE includes an input surface and an output surface opposing the input surface. The gain medium also includes a central region including gain material and extending between the input surface and the output surface along a longitudinal optical axis of the gain medium. The gain medium further includes an edge cladding region surrounding the central region and extending between the input surface and the output surface along the longitudinal optical axis of the gain medium. The edge cladding region includes the gain material and a dopant operable to absorb light at the gain wavelength.

  12. Study on the activation of styrene-based shape memory polymer by medium-infrared laser light

    SciTech Connect

    Leng Jinsong; Yu Kai; Lan Xin; Zhang Dawei; Liu Yanju

    2010-03-15

    This paper demonstrates the feasibility of shape memory polymer (SMP) activation by medium-infrared laser light. Medium-infrared light is transmitted by an optical fiber embedded in the SMP matrix, and the shape recovery process and temperature distribution are recorded by an infrared camera. Light-induced SMP exhibits potential applications in biomedicines and flexible displays.

  13. Short- and medium-chain fatty acids exhibit antimicrobial activity for oral microorganisms

    PubMed Central

    Huang, Chifu B.; Altimova, Yelena; Myers, Taylor M.; Ebersole, Jeffrey L.

    2011-01-01

    Objectives This study assessed the antibacterial activity of short-, medium-, and long-chain fatty acids against various oral microorganisms. Methods The short-chain fatty acids [formic acid (C1), acetic acid (C2), propionic acid (C3), butyric acid (C4), isobutyric acid (C4), isovaleric acid (C5), hexanoic acid (C6)], medium-chain fatty acids [octanoic acid (C8), capric acid (C10), lauric acid (12)], and long-chain fatty acids [myristic acid (C14), palmitic acid (C16)], were investigated for antimicrobial activity against Streptococcus mutans, S. gordonii, S. sanguis, Candida albicans, Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, and Porphyromonas gingivalis. Results The data demonstrated that the fatty acids exhibited patterns of inhibition against oral bacteria with some specificity that appeared related more to the bacterial species that the general structural characteristics of the microorganism. As a group the fatty acids were much less effective against C. albicans than the oral bacteria, with effectiveness limited to hexanoic, octanoic, and lauric acids. Formic acid, capric, and lauric acids were broadly inhibitory for the bacteria. Interestingly, fatty acids that are produced at metabolic end-products by a number of these bacteria, were specifically inactive against the producing species, while substantially inhibiting the growth of other oral microorganisms. Conclusions The results indicate that the antimicrobial activity of short-chain fatty acids (SCFAs), medium-chain fatty acids (MCFAs), long-chain fatty acids (LCFAs) could influence the microbial ecology in the oral cavity via at least 2 potential pathways. First, the agents delivered exogenously as therapeutic adjuncts could be packaged to enhance a microbial-regulatory environment in the subgingival sulcus. Second, it would be the intrinsic nature of these fatty acid inhibitors in contributing to the characteristics of the microbial biofilms, their evolution, and emergence of

  14. Observation of power gain in an inductive pulsed power system with an optically activated semiconductor closing and opening switch

    NASA Astrophysics Data System (ADS)

    Kung, Chun C.; Funk, Eric E.; Chauchard, Eve A.; Rhee, M. J.; Lee, Chi H.; Yan, Li

    1991-03-01

    Peak power gain greater than 15 was obtained with a current charged transmission line and an optically activated semiconductor opening switch. The optical pulse used for activating the switch is generated by a Nd:glass laser emitting at 1. 054 pm. It has a slow rise-time (''--''2OO uS) and a fast fall-time (s1O uS). In the experiment a 2 kV output voltage pulse was achieved with a 5 mm cube GaAs p-i-n diode sitch at 500 V charging voltage.

  15. Self-propulsion and interactions of catalytic particles in a chemically active medium

    NASA Astrophysics Data System (ADS)

    Banigan, Edward J.; Marko, John F.

    2016-01-01

    Enzymatic "machines," such as catalytic rods or colloids, can self-propel and interact by generating gradients of their substrates. We theoretically investigate the behaviors of such machines in a chemically active environment where their catalytic substrates are continuously synthesized and destroyed, as occurs in living cells. We show how the kinetic properties of the medium modulate self-propulsion and pairwise interactions between machines, with the latter controlled by a tunable characteristic interaction range analogous to the Debye screening length in an electrolytic solution. Finally, we discuss the effective force arising between interacting machines and possible biological applications, such as partitioning of bacterial plasmids.

  16. Longevity of U cells of differentiated yeast colonies grown on respiratory medium depends on active glycolysis.

    PubMed

    Čáp, Michal; Váchová, Libuše; Palková, Zdena

    2015-01-01

    Colonies of Saccharomyces cerevisiae laboratory strains pass through specific developmental phases when growing on solid respiratory medium. During entry into the so-called alkali phase, in which ammonia signaling is initiated, 2 prominent cell types are formed within the colonies: U cells in upper colony regions, which have a longevity phenotype and activate the expression of a large number of metabolic genes, and L cells in lower regions, which die more quickly and exhibit a starvation phenotype. Here, we performed a detailed analysis of the activities of enzymes of central carbon metabolism in lysates of both cell types and determined several fermentation end products, showing that previously reported expression differences are reflected in the different enzymatic capabilities of each cell type. Hence, U cells, despite being grown on respiratory medium, behave as fermenting cells, whereas L cells rely on respiratory metabolism and possess active gluconeogenesis. Using a spectrum of different inhibitors, we showed that glycolysis is essential for the formation, and particularly, the survival of U cells. We also showed that β-1,3-glucans that are released from the cell walls of L cells are the most likely source of carbohydrates for U cells.

  17. Nanocrystals of medium soluble actives--novel concept for improved dermal delivery and production strategy.

    PubMed

    Zhai, Xuezhen; Lademann, Jürgen; Keck, Cornelia M; Müller, Rainer H

    2014-08-15

    After use in oral pharmaceutical products, nanocrystals are meanwhile applied to improve the dermal penetration of cosmetic actives (e.g. rutin, hesperidin) and of drugs. By now, nanocrystals are only dermally applied made from poorly soluble actives. The novel concept is to formulate nanocrystals also from medium soluble actives, and to apply a dermal formulation containing additionally nanocrystals. The nanocrystals should act as fast dissolving depot, increase saturation solubility and especially accumulate in the hair follicles, to further increase skin penetration. Caffeine was used as model compound with relevance to market products, and a particular process was developed for the production of caffeine nanocrystals to overcome the supersaturation related effect of crystal growth and fiber formation - typical with medium soluble compounds. It is based on low energy milling (pearl milling) in combination with low dielectric constant dispersion media (water-ethanol or ethanol-propylene glycol mixtures) and optimal stabilizers. Most successful was Carbopol(®) 981 (e.g. 20% caffeine in ethanol-propylene glycol 3:7 with 2% Carbopol, w/w). Nanocrystals with varied sizes can now be produced in a controlled process e.g. 660 nm (optimal for hair follicle accumulation) to 250 nm (optimal for fast dissolution). The short term test proved stability over 2 months of the present formulation being sufficient to perform in vivo testing of the novel concept.

  18. Medium chain fatty acid ethyl esters - activation of antimicrobial effects by Malassezia enzymes.

    PubMed

    Mayser, Peter

    2015-04-01

    Free medium and short chain fatty acids are known to have broad antimicrobial activity. However, their practical use in topical therapy is limited by their intensive smell and acidity. Surprisingly, a nearly identical antimicrobial effect was found with the ethyl ester derivatives of these fatty acids, but only against Malassezia (M.) yeast, not against Candida spp. Obviously, these esters are hydrolysed by M. enzymes, thus generating a selective activation of antimicrobial activity especially in areas well populated with these yeast ('targeting'). Octanoic acid ethyl ester (CAS 106-32-1) was found to be most suitable. In an agar dilution test, the minimal inhibitory concentrations against M. globosa, M. pachydermatis and M. sympodialis, respectively, ranged between ~5 and 10 mmol l(-1) after 10 days of incubation. The effect started immediately and was not delayed by other lipid sources applied simultaneously. Based on these data, fatty acid monoesters may represent a new therapeutic concept in M.-associated diseases. PMID:25676074

  19. Determinants of Developmental Gain in Daily Activities in Young Children with Cerebral Palsy.

    PubMed

    Kruijsen-Terpstra, Anne J A; Ketelaar, Marjolijn; Verschuren, Olaf; Smits, Dirk-Wouter; Jongmans, Marian J; Gorter, Jan Willem

    2014-09-18

    ABSTRACT The aim of this study was to examine which child and family characteristics at the child's age of 2 years are determinants of development of self-care and mobility activities over a period of 2 years in young children with cerebral palsy (CP). Longitudinal data of 92 children, representing all levels of the Gross Motor Function Classification System (GMFCS), were analyzed. Children's self-care and mobility activities were assessed with the Functional Skills Scale of the Pediatric Evaluation of Disability Inventory. Development of self-care and mobility activities was related to several child determinants but no family determinants. GMFCS, type of CP, intellectual capacity, and epilepsy were related to the development of self-care and mobility activities, while manual ability and spasticity were related to development of mobility activities. Multivariate analysis indicated that GMFCS and intellectual capacity were the strongest determinants of development of self-care activities, and GMFCS was the strongest determinant of development of mobility activities. The change in self-care and mobility activities was less favorable in severely affected children with severe disability. Knowledge of GMFCS level and intellectual capacity is important in anticipating change over time and goal setting in young children with CP.

  20. Doped Contacts for High-Longevity Optically Activated, High Gain GaAs Photoconductive Semiconductor Switches

    SciTech Connect

    MAR,ALAN; LOUBRIEL,GUILLERMO M.; ZUTAVERN,FRED J.; O'MALLEY,MARTIN W.; HELGESON,WESLEY D.; BROWN,DARWIN JAMES; HJALMARSON,HAROLD P.; BACA,ALBERT G.; THORNTON,R.L.; DONALDSON,R.D.

    1999-12-17

    The longevity of high gain GaAs photoconductive semiconductor switches (PCSS) has been extended to over 100 million pulses. This was achieved by improving the ohmic contacts through the incorporation of a doped layer that is very effective in the suppression of filament formation, alleviating current crowding. Damage-free operation is now possible with virtually infinite expected lifetime at much higher current levels than before. The inherent damage-free current capacity of the bulk GaAs itself depends on the thickness of the doped layers and is at least 100A for a dopant diffusion depth of 4pm. The contact metal has a different damage mechanism and the threshold for damage ({approx}40A) is not further improved beyond a dopant diffusion depth of about 2{micro}m. In a diffusion-doped contact switch, the switching performance is not degraded when contact metal erosion occurs, unlike a switch with conventional contacts. This paper will compare thermal diffusion and epitaxial growth as approaches to doping the contacts. These techniques will be contrasted in terms of the fabrication issues and device characteristics.

  1. Doped Contacts for High-Longevity Optically Activated, High Gain GaAs Photoconductive Semiconductor Switches

    SciTech Connect

    Baca, A.G.; Brown, D.J.; Donaldson, R.D.; Helgeson, W.D.; Hjalmarson, H.P.; Loubriel, G.M.; Mar, A.; O'Malley, M.W.; Thornton, R.L.; Zutavern, F.J.

    1999-08-05

    The longevity of high gain GaAs photoconductive semiconductor switches (PCSS) has been extended to over 50 million pulses. This was achieved by improving the ohmic contacts through the incorporation of a doped layer beneath the PCSS contacts which is very effective in the suppression of filament formation and alleviating current crowding to improve the longevity of PCSS. Virtually indefinite, damage-free operation is now possible at much higher current levels than before. The inherent damage-free current capacity of the switch depends on the thickness of the doped layers and is at least 100A for a dopant diffusion depth of 4pm. The contact metal has a different damage mechanism and the threshold for damage ({approximately}40A) is not further improved beyond a dopant diffusion depth of about 2{micro}m. In a diffusion-doped contact switch, the switching performance is not degraded when contact metal erosion occurs. This paper will compare thermal diffusion and epitaxial growth as approaches to doping the contacts. These techniques will be contrasted in terms of the fabrication issues and device characteristics.

  2. Different synchronization characteristics of distinct types of traveling waves in a model of active medium with periodic boundary conditions

    NASA Astrophysics Data System (ADS)

    Shepelev, Igor A.; Slepnev, Andrei V.; Vadivasova, Tatiana E.

    2016-09-01

    The model of a one-dimensional active medium, which cells are the FitzHugh-Nagumo oscillators, is studied for periodical boundary conditions. The medium possesses three different regimes in dependence on the parameter values. The regimes correspond to the self-sustained oscillations, excitable dynamics or bistability of the medium cells. Periodic boundary conditions provide the existence of traveling wave modes in all mentioned cases without any deterministic or stochastic excitation. The spatial waveforms and the character of oscillations in time can be similar in the different cases, but the properties of wave modes depend considerably on the medium regime. So, the dispersion characteristics and the synchronization phenomena are essentially different for bistable and excitable media on the one hand, and for the self-sustained oscillatory medium on the other hand. The local and distributed periodic influence on the medium are studied. The phenomenon of the traveling wave frequency locking is observed for all three regimes of the active medium. The comparison of synchronization effects in self-oscillatory, excitable and bistable regimes of the active medium is carried out.

  3. Cell Motility Is Decreased in Macrophages Activated by Cancer Cell-Conditioned Medium

    PubMed Central

    Go, Ahreum; Ryu, Yun-Kyoung; Lee, Jae-Wook; Moon, Eun-Yi

    2013-01-01

    Macrophages play a role in innate immune responses to various foreign antigens. Many products from primary tumors influence the activation and transmigration of macrophages. Here, we investigated a migration of macrophages stimulated with cancer cell culture-conditioned medium (CM). Macrophage activation by treatment with CM of B16F10 cells were judged by the increase in protein levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX2). The location where macrophages were at 4 h-incubation with control medium or CM was different from where they were at 5 h-incubation in culture dish. Percentage of superimposed macrophages at every 1 h interval was gradually increased by CM treatment as compared to control. Total coverage of migrated track expressed in coordinates was smaller and total distance of migration was shorter in CM-treated macrophages than that in control. Rac1 activity in CM-treated macrophages was also decreased as compared to that in control. When macrophages were treated with CM in the presence of dexamethasone (Dex), an increase in COX2 protein levels, and a decrease in Rac1 activity and total coverage of migration were reversed. In the meanwhile, biphasic changes were detected by Dex treatment in section distance of migration at each time interval, which was more decreased at early time and then increased at later time. Taken together, data demonstrate that macrophage motility could be reduced in accordance with activation in response to cancer cell products. It suggests that macrophage motility could be a novel marker to monitor cancer-associated inflammatory diseases and the efficacy of anti-inflammatory agents. PMID:24404340

  4. Arctigenin Inhibits Adipogenesis by Inducing AMPK Activation and Reduces Weight Gain in High-Fat Diet-Induced Obese Mice.

    PubMed

    Han, Yo-Han; Kee, Ji-Ye; Park, Jinbong; Kim, Hye-Lin; Jeong, Mi-Young; Kim, Dae-Seung; Jeon, Yong-Deok; Jung, Yunu; Youn, Dong-Hyun; Kang, JongWook; So, Hong-Seob; Park, Raekil; Lee, Jong-Hyun; Shin, Soyoung; Kim, Su-Jin; Um, Jae-Young; Hong, Seung-Heon

    2016-09-01

    Although arctigenin (ARC) has been reported to have some pharmacological effects such as anti-inflammation, anti-cancer, and antioxidant, there have been no reports on the anti-obesity effect of ARC. The aim of this study is to investigate whether ARC has an anti-obesity effect and mediates the AMP-activated protein kinase (AMPK) pathway. We investigated the anti-adipogenic effect of ARC using 3T3-L1 pre-adipocytes and human adipose tissue-derived mesenchymal stem cells (hAMSCs). In high-fat diet (HFD)-induced obese mice, whether ARC can inhibit weight gain was investigated. We found that ARC reduced weight gain, fat pad weight, and triglycerides in HFD-induced obese mice. ARC also inhibited the expression of peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT/enhancer-binding protein alpha (C/EBPα) in in vitro and in vivo. Furthermore, ARC induced the AMPK activation resulting in down-modulation of adipogenesis-related factors including PPARγ, C/EBPα, fatty acid synthase, adipocyte fatty acid-binding protein, and lipoprotein lipase. This study demonstrates that ARC can reduce key adipogenic factors by activating the AMPK in vitro and in vivo and suggests a therapeutic implication of ARC for obesity treatment. J. Cell. Biochem. 117: 2067-2077, 2016. © 2016 Wiley Periodicals, Inc.

  5. Arctigenin Inhibits Adipogenesis by Inducing AMPK Activation and Reduces Weight Gain in High-Fat Diet-Induced Obese Mice.

    PubMed

    Han, Yo-Han; Kee, Ji-Ye; Park, Jinbong; Kim, Hye-Lin; Jeong, Mi-Young; Kim, Dae-Seung; Jeon, Yong-Deok; Jung, Yunu; Youn, Dong-Hyun; Kang, JongWook; So, Hong-Seob; Park, Raekil; Lee, Jong-Hyun; Shin, Soyoung; Kim, Su-Jin; Um, Jae-Young; Hong, Seung-Heon

    2016-09-01

    Although arctigenin (ARC) has been reported to have some pharmacological effects such as anti-inflammation, anti-cancer, and antioxidant, there have been no reports on the anti-obesity effect of ARC. The aim of this study is to investigate whether ARC has an anti-obesity effect and mediates the AMP-activated protein kinase (AMPK) pathway. We investigated the anti-adipogenic effect of ARC using 3T3-L1 pre-adipocytes and human adipose tissue-derived mesenchymal stem cells (hAMSCs). In high-fat diet (HFD)-induced obese mice, whether ARC can inhibit weight gain was investigated. We found that ARC reduced weight gain, fat pad weight, and triglycerides in HFD-induced obese mice. ARC also inhibited the expression of peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT/enhancer-binding protein alpha (C/EBPα) in in vitro and in vivo. Furthermore, ARC induced the AMPK activation resulting in down-modulation of adipogenesis-related factors including PPARγ, C/EBPα, fatty acid synthase, adipocyte fatty acid-binding protein, and lipoprotein lipase. This study demonstrates that ARC can reduce key adipogenic factors by activating the AMPK in vitro and in vivo and suggests a therapeutic implication of ARC for obesity treatment. J. Cell. Biochem. 117: 2067-2077, 2016. © 2016 Wiley Periodicals, Inc. PMID:26852013

  6. Gain and kinetics of activation in the G-protein cascade of phototransduction.

    PubMed Central

    Lamb, T D

    1996-01-01

    The guanine nucleotide binding protein (G protein) cascade underlying phototransduction is one of the best understood of all signaling pathways. The diffusional interactions of the proteins underlying the cascade have been analyzed, both at a macroscopic level and also in terms of the stochastic nature of the molecular contacts. In response to a single activated rhodopsin (R*) formed as a result of a single photon hit, it can be shown that molecules of the G-protein transducin will be activated approximately linearly with time. This, in turn, will cause the number of activated molecules of the effector protein (the phosphodiesterase) also to increase linearly with time. These kinetics of protein activation provide an accurate description of the time course of the rising phase of the photoreceptor's electrical response over a wide range of flash intensities. Recent estimates indicate that at room temperature each R* triggers activation of the phosphodiesterase at a rate of 1000-2000 subunits.s-1. Now that a quantitative description of the activation steps in transduction has been obtained, perhaps the greatest challenge for the future is to provide a comprehensive description of the shutoff reactions, so that a complete account of the photoreceptor's response to light can be achieved. Images Fig. 1 Fig. 2 PMID:8570596

  7. Coupled-resonator vertical-cavity lasers with two active gain regions

    DOEpatents

    Fischer, Arthur J.; Choquette, Kent D.; Chow, Weng W.

    2003-05-20

    A new class of coupled-resonator vertical-cavity semiconductor lasers has been developed. These lasers have multiple resonant cavities containing regions of active laser media, resulting in a multi-terminal laser component with a wide range of novel properties.

  8. Cortical activation changes underlying stimulation-induced behavioural gains in chronic stroke

    PubMed Central

    Bachtiar, Velicia; O'Shea, Jacinta; Allman, Claire; Bosnell, Rosemary Ann; Kischka, Udo; Matthews, Paul McMahan; Johansen-Berg, Heidi

    2012-01-01

    Transcranial direct current stimulation, a form of non-invasive brain stimulation, is showing increasing promise as an adjunct therapy in rehabilitation following stroke. However, although significant behavioural improvements have been reported in proof-of-principle studies, the underlying mechanisms are poorly understood. The rationale for transcranial direct current stimulation as therapy for stroke is that therapeutic stimulation paradigms increase activity in ipsilesional motor cortical areas, but this has not previously been directly tested for conventional electrode placements. This study was performed to test directly whether increases in ipsilesional cortical activation with transcranial direct current stimulation are associated with behavioural improvements in chronic stroke patients. Patients at least 6 months post-first stroke participated in a behavioural experiment (n = 13) or a functional magnetic resonance imaging experiment (n = 11), each investigating the effects of three stimulation conditions in separate sessions: anodal stimulation to the ipsilesional hemisphere; cathodal stimulation to the contralesional hemisphere; and sham stimulation. Anodal (facilitatory) stimulation to the ipsilesional hemisphere led to significant improvements (5–10%) in response times with the affected hand in both experiments. This improvement was associated with an increase in movement-related cortical activity in the stimulated primary motor cortex and functionally interconnected regions. Cathodal (inhibitory) stimulation to the contralesional hemisphere led to a functional improvement only when compared with sham stimulation. We show for the first time that the significant behavioural improvements produced by anodal stimulation to the ipsilesional hemisphere are associated with a functionally relevant increase in activity within the ipsilesional primary motor cortex in patients with a wide range of disabilities following stroke. PMID:22155982

  9. Cortical activation changes underlying stimulation-induced behavioural gains in chronic stroke.

    PubMed

    Stagg, Charlotte Jane; Bachtiar, Velicia; O'Shea, Jacinta; Allman, Claire; Bosnell, Rosemary Ann; Kischka, Udo; Matthews, Paul McMahan; Johansen-Berg, Heidi

    2012-01-01

    Transcranial direct current stimulation, a form of non-invasive brain stimulation, is showing increasing promise as an adjunct therapy in rehabilitation following stroke. However, although significant behavioural improvements have been reported in proof-of-principle studies, the underlying mechanisms are poorly understood. The rationale for transcranial direct current stimulation as therapy for stroke is that therapeutic stimulation paradigms increase activity in ipsilesional motor cortical areas, but this has not previously been directly tested for conventional electrode placements. This study was performed to test directly whether increases in ipsilesional cortical activation with transcranial direct current stimulation are associated with behavioural improvements in chronic stroke patients. Patients at least 6 months post-first stroke participated in a behavioural experiment (n = 13) or a functional magnetic resonance imaging experiment (n = 11), each investigating the effects of three stimulation conditions in separate sessions: anodal stimulation to the ipsilesional hemisphere; cathodal stimulation to the contralesional hemisphere; and sham stimulation. Anodal (facilitatory) stimulation to the ipsilesional hemisphere led to significant improvements (5-10%) in response times with the affected hand in both experiments. This improvement was associated with an increase in movement-related cortical activity in the stimulated primary motor cortex and functionally interconnected regions. Cathodal (inhibitory) stimulation to the contralesional hemisphere led to a functional improvement only when compared with sham stimulation. We show for the first time that the significant behavioural improvements produced by anodal stimulation to the ipsilesional hemisphere are associated with a functionally relevant increase in activity within the ipsilesional primary motor cortex in patients with a wide range of disabilities following stroke.

  10. Dependence of synchronized bursting activity on medium stirring and the perfusion rate in a cultured network of neurons

    NASA Astrophysics Data System (ADS)

    Heo, Ryoun; Kim, Hyun; Lee, Kyoung J.

    2016-05-01

    A cultured network of neurons coupled with a multi-electrode-array (MEA) recording system has been a useful platform for investigating various issues in neuroscience and engineering. The neural activity supported by the system can be sensitive to environmental fluctuations, for example, in the medium's nutrient composition, ph, and temperature, and to mechanical disturbances, yet this issue has not been the subject. Especially, a normal practice in maintaining neuronal cell cultures involves an intermittent sequence of medium exchanges, typically at a time interval of a few days, and one such sudden medium exchange is unavoidably accompanied by many unintended disturbances. Here, based on a quantitative time-series analysis of synchronized bursting events, we explicitly demonstrate that such a medium exchange can, indeed, bring a huge change in the existing neural activity. Subsequently, we develop a medium perfusion-stirring system and an ideal protocol that can be used in conjunction with a MEA recording system, providing long-term stability. Specifically, we systematically evaluate the effects of medium stirring and perfusion rates. Unexpectedly, even some vigorous mechanical agitations do not have any impacts on neural activity. On the other hand, too much replenishment ( e.g., 1.8 ml/day for a 1.8-ml dish) of neurobasal medium results in an excitotoxicity.

  11. Antitumor effect of synergistic contribution of nitrite and hydrogen peroxide in the plasma activated medium

    NASA Astrophysics Data System (ADS)

    Kurake, Naoyuki; Tanaka, Hiromasa; Ishikawa, Kenji; Nakamura, Kae; Kajiyama, Hiroaki; Kikkawa, Fumiaki; Kondo, Takashi; Mizuno, Masaaki; Takeda, Keigo; Kondo, Hiroki; Sekine, Makoto; Hori, Masaru

    2015-09-01

    Non-equilibrium atmospheric pressure plasmas (NEAPP) have been attracted attention in the noble application of cancer therapy. Although good effects of the Plasma-Activated-Medium (PAM) such as the selective antitumor effect and killing effect for the anticancer agent resistant cells were reported, a mechanism of this effect has not been still clarified yet. In this study, we have investigated a contribution of the reactive nitrogen and oxygen species (RNOS) generated in PAM such as hydrogen peroxide and nitrite. Those species generated in the PAM quantitatively measured by light absorbance of commercial regent. Moreover, viable cell count after cell culture with those RNOS intentionally added medium or PAM were also measured by MTS assay. Our NEAPP source generated hydrogen peroxide and nitrite with the generation ratio of 0.35 μM/s and 9.8 μM/s. In those RNOS, hydrogen peroxide has respective antitumor effect. On the other hands, nitrite has no antitumor effect singly. But, synergistically enhance the antitumor effect of hydrogen peroxide. Moreover, this effect of those RNOS also contribute for the selectively cancer killing effect of PAM.

  12. Dermal nanocrystals from medium soluble actives - physical stability and stability affecting parameters.

    PubMed

    Zhai, Xuezhen; Lademann, Jürgen; Keck, Cornelia M; Müller, Rainer H

    2014-09-01

    Nanocrystals are meanwhile applied to increase the dermal penetration of drugs, but were applied by now only to poorly soluble drugs (e.g. 1-10 μg/ml). As a new concept nanocrystals from medium soluble actives were produced, using caffeine as model compound (solubility 16 mg/ml at 20 °C). Penetration should be increased by (a) further increase in solubility and (b) mainly by increased hair follicle targeting of nanocrystals compared to pure solution. Caffeine nanocrystal production in water lead to pronounced crystal growth. Therefore the stability of nanocrystals in water-ethanol (1:9) and ethanol-propylene glycol (3:7) mixtures with lower dielectric constant D was investigated, using various stabilizers. Both mixtures in combination with Carbopol 981 (non-neutralized) yielded stable nanosuspensions over 2 months at 4 °C and room temperature. Storage at 40 °C lead to crystal growth, attributed to too strong solubility increase, supersaturation and Ostwald ripening effects. Stability of caffeine nanocrystals at lower temperatures could not only be attributed to lower solubility, because the solubilities of caffeine in mixtures and in water are not that much different. Other effects such as quantified by reduced dielectric constant D, and specific interactions between dispersion medium and crystal surface seem to play a role. With the 2 mixtures and Carbopol 981, a basic formulation composition for this type of nanocrystals has been established, to be used in the in vivo proof of principle of the new concept.

  13. Dermal nanocrystals from medium soluble actives - physical stability and stability affecting parameters.

    PubMed

    Zhai, Xuezhen; Lademann, Jürgen; Keck, Cornelia M; Müller, Rainer H

    2014-09-01

    Nanocrystals are meanwhile applied to increase the dermal penetration of drugs, but were applied by now only to poorly soluble drugs (e.g. 1-10 μg/ml). As a new concept nanocrystals from medium soluble actives were produced, using caffeine as model compound (solubility 16 mg/ml at 20 °C). Penetration should be increased by (a) further increase in solubility and (b) mainly by increased hair follicle targeting of nanocrystals compared to pure solution. Caffeine nanocrystal production in water lead to pronounced crystal growth. Therefore the stability of nanocrystals in water-ethanol (1:9) and ethanol-propylene glycol (3:7) mixtures with lower dielectric constant D was investigated, using various stabilizers. Both mixtures in combination with Carbopol 981 (non-neutralized) yielded stable nanosuspensions over 2 months at 4 °C and room temperature. Storage at 40 °C lead to crystal growth, attributed to too strong solubility increase, supersaturation and Ostwald ripening effects. Stability of caffeine nanocrystals at lower temperatures could not only be attributed to lower solubility, because the solubilities of caffeine in mixtures and in water are not that much different. Other effects such as quantified by reduced dielectric constant D, and specific interactions between dispersion medium and crystal surface seem to play a role. With the 2 mixtures and Carbopol 981, a basic formulation composition for this type of nanocrystals has been established, to be used in the in vivo proof of principle of the new concept. PMID:25016978

  14. Comparative studies on extracts from Hericium erinaceus by different polarity reagents to gain higher antioxidant activities

    PubMed Central

    JIANG, SHENGJUAN; WANG, YULIANG; ZHANG, XIAOLONG

    2016-01-01

    Hericium erinaceus (H. erinaceus) is a source of exogenous antioxidants that has been traditionally used in China for the prevention and treatment of oxidative stress-associated disease. In the present study, the bioactive compounds of H. erinaceus were extracted with the following eight representative reagents: n-Hexane, xylene, chloroform, anhydrous ether, ethyl acetate, acetone, anhydrous ethanol and distilled water. The in vitro antioxidant activities were also evaluated. All of the extracted compounds exhibited reducing power and scavenging activity against 1-diphenyl-2-picrylhydrazyl (DPPH) and superoxide anion free radicals. In addition, the antioxidant capacities varied with the used chemical reagents and exhibited dose-dependent effects. Extracts from anhydrous ethanol, chloroform and acetone were capable of inhibiting lipid peroxidation. The anhydrous ethanol extracts were observed to have significant levels of antioxidant compounds since they had a strong reducing power, high scavenging rates against DPPH and superoxide anion-free radicals (>90%), and high inhibition rates on lipid peroxidation (>60%). The present study will provide reference data for the antioxidant applications of H. erinaceus in pharmaceutical use and disease prevention. PMID:27347087

  15. Is excessive online usage a function of medium or activity? An empirical pilot study

    PubMed Central

    Griffiths, Mark D.; Szabo, Attila

    2014-01-01

    Aims: The purpose of the study was to seek a better insight into whether the online medium or the online activity was more important in relation to excessive online use. It is not clear whether those people who spend excessive amounts of time on the Internet are engaged in general Internet or whether excessive Internet use is linked to specific activities. Methods: Perceived changes in Internet use habits as function of hypothetical accessibility of favorite sites were investigated in young adults. University students (n = 130, mean age = 20.6 years) who had (on average) spent over 20 hours a week on the Internet for at least nine years completed a survey. The most favored online activities and expected quality of life without Internet access were also investigated. Results: Findings revealed that social networking was by far the most popular online activity, and that lack of access to their preferred online activities would drop by 65% (as measured by perceived Internet usage). Approximately one in six participants (16%) claimed they would not even switch on the computer if access to their favorite online activities were unavailable. In relation to a hypothetical question about the quality of life without Internet access, the responses were normally distributed (rather than skewed). Conclusions: These results show that time spent with Internet activity is not random and/or generalized, but appears more focused. Attraction or addiction on Internet to one or more specific behavior(s) may be a better way forward in the quest for better understanding excessive human behavior in the online environment. PMID:25215216

  16. Enhancement of Cellulase Activity from a New Strain of Bacillus subtilis by Medium Optimization and Analysis with Various Cellulosic Substrates

    PubMed Central

    Deka, Deepmoni; Bhargavi, P.; Sharma, Ashish; Goyal, Dinesh; Jawed, M.; Goyal, Arun

    2011-01-01

    The cellulase activity of Bacillus subtilis AS3 was enhanced by optimizing the medium composition by statistical methods. The enzyme activity with unoptimised medium with carboxymethylcellulose (CMC) was 0.07 U/mL and that was significantly enhanced by CMC, peptone, and yeast extract using Placket-Burman design. The combined effects of these nutrients on cellulase activity were studied using 22 full factorial central composite design. The optimal levels of medium components determined were CMC (1.8%), peptone (0.8%), and yeast extract (0.479%). The maximum enzyme activity predicted by the model was 0.49 U/mL which was in good agreement with the experimental value 0.43 U/mL showing 6-fold increase as compared to unoptimised medium. The enzyme showed multisubstrate specificity, showing significantly higher activity with lichenan and β-glucan and lower activity with laminarin, hydroxyethylcellulose, and steam exploded bagasse. The optimised medium with lichenan or β-glucan showed 2.5- or 2.8-fold higher activity, respectively, at same concentration as of CMC. PMID:21637325

  17. Variable susceptibility of ovarian cancer cells to non-thermal plasma-activated medium

    PubMed Central

    UTSUMI, FUMI; KAJIYAMA, HIROAKI; NAKAMURA, KAE; TANAKA, HIROMASA; MIZUNO, MASAAKI; TOYOKUNI, SHINNYA; HORI, MASARU; KIKKAWA, FUMITAKA

    2016-01-01

    Non-thermal atmospheric pressure plasma has been widely studied in recent years in many fields, including cancer treatment. However, its efficiency for inducing apoptosis sometimes varies depending on the cell species and experimental conditions. The aim of this study was to elucidate what causes these differences in responses to plasma treatment. Using four ovarian cancer cell lines, the cell density had a markedly negative impact on the proliferation inhibition rate (PIR) and it was more obvious in OVCAR-3 and NOS2 cells. Furthermore, TOV21G and ES-2 cells were drastically sensitive to plasma-activated medium (PAM) compared with the other two cell lines. We demonstrated that the proportion of reactive oxygen species and cell number had a marked impact on the effect of PAM against ovarian cancer cells. Additionally it was suggested that the morphological features of cells were also closely related PMID:27035127

  18. Gain control of synaptic response function in cerebellar nuclear neurons by a calcium-activated potassium conductance.

    PubMed

    Feng, Steven Si; Lin, Risa; Gauck, Volker; Jaeger, Dieter

    2013-10-01

    Small conductance Ca(2+)-activated potassium (SK) current provides an important modulator of excitatory synaptic transmission, which undergoes plastic regulation via multiple mechanisms. We examined whether inhibitory input processing is also dependent on SK current in the cerebellar nuclei (CN) where inhibition provides the only route of information transfer from the cerebellar cortical Purkinje cells. We employed dynamic clamping in conjunction with computer simulations to address this question. We found that SK current plays a critical role in the inhibitory synaptic control of spiking output. Specifically, regulation of SK current density resulted in a gain control of spiking output, such that low SK current promoted large output signaling for large inhibitory cell input fluctuations due to Purkinje cell synchronization. In contrast, smaller nonsynchronized Purkinje cell input fluctuations were not amplified. Regulation of SK density in the CN therefore would likely lead to important consequences for the transmission of synchronized Purkinje cell activity to the motor system. PMID:23605187

  19. Chemical properties and antioxidant activity of exopolysaccharides fractions from mycelial culture of Inonotus obliquus in a ground corn stover medium.

    PubMed

    Xiang, Yuling; Xu, Xiangqun; Li, Juan

    2012-10-15

    The medicinal mushroom Inonotus obliquus has been a folk remedy for a long time in East-European and Asian countries. We first reported the enhancement in production and antioxidant activity of exopolysaccharides by I. obliquus culture under lignocellulose decomposition. In this study, the two different sources of exopolysaccharides from the control medium and the lignocellulose (corn stover) containing medium by I. obliquus in submerged fermentation were fractionated and purified by chromatography. The exopolysaccharides from the corn stover-containing medium presented significantly stronger hydroxyl and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity than the control. Three fractions from the control medium and the corn stover-containing medium were isolated respectively. The fraction of DEPL3 from the corn stover-containing medium with the highest protein content (38.3%), mannose content (49.6%), and the lowest molecular weight (29 kDa) had the highest antioxidant activity with the lowest IC50 values. In conclusion, lignocellulose decomposition changed the chemical characterisation and significantly enhanced the antioxidant activity of exopolysaccharide fractions.

  20. Assessment of highly active dune mobility in the medium, short and very short term

    NASA Astrophysics Data System (ADS)

    Navarro, Marina; Muñoz-Pérez, Juan J.; Román-Sierra, Jorge; Tsoar, Haim; Rodríguez, Inmaculada; Gómez-Pina, Gregorio

    2011-06-01

    Dune activity or stability has usually been studied over long time periods; however, this may not reflect changes that occur in the short term, especially for highly active dunefields. Extreme wind conditions that are generated near the Strait of Gibraltar (SW Spain) have given rise to the transgressive Valdevaqueros dunefield. The current work focuses on analyzing the sand drift potential and the evolution of the dune profile in the medium term (months), the short term (days) and the very short term (hours). Topographic data, which were collected with a differential GPS, were interpreted from reconstructed empirical orthogonal functions (EOF). The results showed that generally the dune profile presented shifting morphologies, especially around the crest and brink, and a trend towards migration to a gentler steady state. As a result, the leeward side adopted continuous slope variations during the different survey periods, whereas the windward slope did not undergo any significant change. Lateral and vertical displacements were analyzed during a severe easterly sandstorm, when the dune brink experienced an advance migration rate of 1.75 m in 24 h. Sand transport rates of 25.5-36.5 m 3 m - 1 month - 1 , 22.52 m 3 m - 1 day - 1 and 0.93 m 3 m - 1 h - 1 were measured for the medium term, short term and very short term, respectively. These values were compared to the theoretical sand transport rate for Valdevaqueros dune, based on the classic Bagnold equation as well other more recent formulae, to obtain a ratio between the real and the theoretical rates for each study period. These results together with the sand drift potential (up to 10,000 vector units) demonstrate that Valdevaqueros (Tarifa) is a dunefield with one of the highest sand transport capacities in Europe.

  1. Regulation of Nucleotide Metabolism by Mutant p53 Contributes to its Gain-of-Function Activities

    PubMed Central

    Kollareddy, Madhusudhan; Dimitrova, Elizabeth; Vallabhaneni, Krishna C.; Chan, Adriano; Le, Thuc; Chauhan, Krishna M.; Carrero, Zunamys I.; Ramakrishnan, Gopalakrishnan; Watabe, Kounosuke; Haupt, Ygal; Haupt, Sue; Pochampally, Radhika; Boss, Gerard R.; Romero, Damian G.; Radu, Caius G.; Martinez, Luis A.

    2015-01-01

    SUMMARY Mutant p53 (mtp53) is an oncogene that drives cancer cell proliferation. Here we report that mtp53 associates with the promoters of numerous nucleotide metabolism genes (NMG). Mtp53 knockdown reduces NMG expression and substantially depletes nucleotide pools, which attenuates GTP dependent protein (GTPase) activity and cell invasion. Addition of exogenous guanosine or GTP restores the invasiveness of mtp53 knockdown cells, suggesting that mtp53 promotes invasion by increasing GTP. Additionally, mtp53 creates a dependency on the nucleoside salvage pathway enzyme deoxycytidine kinase (dCK) for the maintenance of a proper balance in dNTP pools required for proliferation. These data indicate that mtp53 harboring cells have acquired a synthetic sick or lethal phenotype relationship with the nucleoside salvage pathway. Finally, elevated expression of NMG correlates with mutant p53 status and poor prognosis in breast cancer patients. Thus, mtp53’s control of nucleotide biosynthesis has both a driving and sustaining role in cancer development. PMID:26067754

  2. When your pain signifies my gain: neural activity while evaluating outcomes based on another person's pain.

    PubMed

    Cui, Fang; Zhu, Xiangru; Gu, Ruolei; Luo, Yue-Jia

    2016-01-01

    The overlap between pain and reward processing pathways leds researchers to hypothesize that there are interactions between them in the human brain. Two hypotheses have been proposed. The "competition hypothesis" posits that reward can reduce pain-related neural activity and vice versa. The "salience hypothesis" suggests that the motivational salience of pain and reward can be mutually reinforced. However, no study has tested these two hypotheses from temporal perspective as we know. In the present study, pictures depicted other people in painful or non-painful situations were used to indicate the valence of outcomes in a gambling task. The event-related potential results revealed an interaction between another person's pain and outcome valence in multiple time stages. Specifically, the amplitudes of the N1 and P3 were enhanced in the win condition compared with the loss condition when the outcome was indicated by painful picture. This interactions between pain and reward support the salience hypothesis but not the competition hypothesis. The present results provide evidence from human subjects that support the salience hypothesis, which claims that observing other people's pain can enhance the salience of reward. PMID:27193060

  3. Kinetics of an oxygen - iodine active medium with iodine atoms optically pumped on the 2P1/2 - 2P3/2 transition

    NASA Astrophysics Data System (ADS)

    Zagidullin, M. V.; Malyshev, M. S.; Azyazov, V. N.

    2015-08-01

    The kinetics of the processes occurring in an O2 - I2 - He - H2O gas flow in which photodissociation of molecular iodine at a wavelength close to 500 nm and excitation of atomic iodine on the 2P1/2 - 2P3/2 transition by narrow-band radiation near 1315 nm are implemented successively has been analysed. It is shown that implementation of these processes allows one to form an oxygen - iodine medium with a high degree of dissociation of molecular iodine and a relative content of singlet oxygen O2(a1Δ) exceeding 10%. Having formed a supersonic gas flow with a temperature ~100 K from this medium, one can reach a small-signal gain of about 10-2 cm-1 on the 2P1/2 - 2P3/2 transition in iodine atoms. The specific power per unit flow cross section in the oxygen - iodine laser with this active medium may reach ~100 W cm-2.

  4. GABAA receptor activity shapes the formation of inhibitory synapses between developing medium spiny neurons

    PubMed Central

    Arama, Jessica; Abitbol, Karine; Goffin, Darren; Fuchs, Celine; Sihra, Talvinder S.; Thomson, Alex M.; Jovanovic, Jasmina N.

    2015-01-01

    Basal ganglia play an essential role in motor coordination and cognitive functions. The GABAergic medium spiny neurons (MSNs) account for ~95% of all the neurons in this brain region. Central to the normal functioning of MSNs is integration of synaptic activity arriving from the glutamatergic corticostriatal and thalamostriatal afferents, with synaptic inhibition mediated by local interneurons and MSN axon collaterals. In this study we have investigated how the specific types of GABAergic synapses between the MSNs develop over time, and how the activity of GABAA receptors (GABAARs) influences this development. Isolated embryonic (E17) MSNs form a homogenous population in vitro and display spontaneous synaptic activity and functional properties similar to their in vivo counterparts. In dual whole-cell recordings of synaptically connected pairs of MSNs, action potential (AP)-activated synaptic events were detected between 7 and 14 days in vitro (DIV), which coincided with the shift in GABAAR operation from depolarization to hyperpolarization, as detected indirectly by intracellular calcium imaging. In parallel, the predominant subtypes of inhibitory synapses, which innervate dendrites of MSNs and contain GABAAR α1 or α2 subunits, underwent distinct changes in the size of postsynaptic clusters, with α1 becoming smaller and α2 larger over time, while both the percentage and the size of mixed α1/α2-postsynaptic clusters were increased. When activity of GABAARs was under chronic blockade between 4–7 DIV, the structural properties of these synapses remained unchanged. In contrast, chronic inhibition of GABAARs between 7–14 DIV led to reduction in size of α1- and α1/α2-postsynaptic clusters and a concomitant increase in number and size of α2-postsynaptic clusters. Thus, the main subtypes of GABAergic synapses formed by MSNs are regulated by GABAAR activity, but in opposite directions, and thus appear to be driven by different molecular mechanisms. PMID

  5. Wave propagation in reconfigurable broadband gain metamaterials at microwave frequencies

    NASA Astrophysics Data System (ADS)

    Fan, Yifeng; Nagarkoti, Deepak S.; Rajab, Khalid Z.; Hao, Yang; Zhang, Hao Chi; Cui, Tie Jun

    2016-05-01

    The wave dispersion characteristics for loop array-based metamaterials were analyzed, based on the general transmission line model of a one-dimensional host medium interacting with a chain of coupled loops. By relating the wave propagation constant and the effective parameters of the coupled host medium, we showed that an active medium embedded with non-Foster loaded loop array can be designed to exhibit broadband negative material parameters with positive gain. Accounting for all interactions, the stability of the active medium was investigated, further yielding necessary design specifications for the non-Foster loads. Subsequently, an experimental demonstration was provided to verify the theoretical analysis, showing that stable reconfigurable broadband gain metamaterials at microwave frequencies can be obtained with proper negative impedance converter design.

  6. Thermoregulation of water foraging honeybees--balancing of endothermic activity with radiative heat gain and functional requirements.

    PubMed

    Kovac, Helmut; Stabentheiner, Anton; Schmaranzer, Sigurd

    2010-12-01

    Foraging honeybees are subjected to considerable variations of microclimatic conditions challenging their thermoregulatory ability. Solar heat is a gain in the cold but may be a burden in the heat. We investigated the balancing of endothermic activity with radiative heat gain and physiological functions of water foraging Apis mellifera carnica honeybees in the whole range of ambient temperatures (T(a)) and solar radiation they are likely to be exposed in their natural environment in Middle Europe. The mean thorax temperature (T(th)) during foraging stays was regulated at a constantly high level (37.0-38.5 °C) in a broad range of T(a) (3-30 °C). At warmer conditions (T(a)=30-39 °C) T(th) increased to a maximal level of 45.3 °C. The endothermic temperature excess (difference of T(body)-T(a) of living and dead bees) was used to assess the endogenously generated temperature elevation as a correlate of energy turnover. Up to a T(a) of ∼30 °C bees used solar heat gain for a double purpose: to reduce energetic expenditure and to increase T(th) by about 1-3 °C to improve force production of flight muscles. At higher T(a) they exhibited cooling efforts to get rid of excess heat. A high T(th) also allowed regulation of the head temperature high enough to guarantee proper function of the bees' suction pump even at low T(a). This shortened the foraging stays and this way reduced energetic costs. With decreasing T(a) bees also reduced arrival body weight and crop loading to do both minimize costs and optimize flight performance. PMID:20705071

  7. Thermoregulation of water foraging honeybees—Balancing of endothermic activity with radiative heat gain and functional requirements

    PubMed Central

    Kovac, Helmut; Stabentheiner, Anton; Schmaranzer, Sigurd

    2010-01-01

    Foraging honeybees are subjected to considerable variations of microclimatic conditions challenging their thermoregulatory ability. Solar heat is a gain in the cold but may be a burden in the heat. We investigated the balancing of endothermic activity with radiative heat gain and physiological functions of water foraging Apis mellifera carnica honeybees in the whole range of ambient temperatures (Ta) and solar radiation they are likely to be exposed in their natural environment in Middle Europe. The mean thorax temperature (Tth) during foraging stays was regulated at a constantly high level (37.0–38.5 °C) in a broad range of Ta (3–30 °C). At warmer conditions (Ta = 30–39 °C) Tth increased to a maximal level of 45.3 °C. The endothermic temperature excess (difference of Tbody − Ta of living and dead bees) was used to assess the endogenously generated temperature elevation as a correlate of energy turnover. Up to a Ta of ∼30 °C bees used solar heat gain for a double purpose: to reduce energetic expenditure and to increase Tth by about 1–3 °C to improve force production of flight muscles. At higher Ta they exhibited cooling efforts to get rid of excess heat. A high Tth also allowed regulation of the head temperature high enough to guarantee proper function of the bees’ suction pump even at low Ta. This shortened the foraging stays and this way reduced energetic costs. With decreasing Ta bees also reduced arrival body weight and crop loading to do both minimize costs and optimize flight performance. PMID:20705071

  8. Effects of cultural medium on the formation and antitumor activity of polysaccharides by Cordyceps gunnii.

    PubMed

    Zhu, Zhen-Yuan; Liu, Xiao-Cui; Tang, Ya-Li; Dong, Feng-Ying; Sun, Hui-Qing; Chen, Lu; Zhang, Yong-Min

    2016-10-01

    The effects of culture medium composition (i.e., carbon and nitrogen sources) on the growth of mycelia, molecular weight distribution and antitumor activity of intracellular polysaccharides (IPS) from Cordyceps gunnii were investigated. Sucrose and peptone were proved to be the best carbon and nitrogen sources for mycelia growth and remarkably improved IPS production. When the sucrose concentration was 2.0%, the mycelium yield reached up to 15.94±1.26 g/L, but with lower IPS yield; whereas the sucrose concentration was 4.5%, IPS yield reached to a maximum of 138.78±3.89 mg/100 mL. The effects of different carbon/nitrogen (C/N) ratios with equal amounts of carbon source matter on the mycelia and IPS formation were optimized. It found that the yield of mycelia and IPS were both reached to the highest at a C/N ratio of 10:3. In addition, the IPS had the highest macro molecular polysaccharide content and antitumor activity when sucrose concentration was 3.5% and the C/N ratio was 10:1.5. Thus, there was a positive correlation between molecular weight distribution and antitumor activity of IPS by C. gunnii. PMID:27074949

  9. Serratia marcescens Quinoprotein Glucose Dehydrogenase Activity Mediates Medium Acidification and Inhibition of Prodigiosin Production by Glucose

    PubMed Central

    Fender, James E.; Bender, Cody M.; Stella, Nicholas A.; Lahr, Roni M.; Kalivoda, Eric J.

    2012-01-01

    Serratia marcescens is a model organism for the study of secondary metabolites. The biologically active pigment prodigiosin (2-methyl-3-pentyl-6-methoxyprodiginine), like many other secondary metabolites, is inhibited by growth in glucose-rich medium. Whereas previous studies indicated that this inhibitory effect was pH dependent and did not require cyclic AMP (cAMP), there is no information on the genes involved in mediating this phenomenon. Here we used transposon mutagenesis to identify genes involved in the inhibition of prodigiosin by glucose. Multiple genetic loci involved in quinoprotein glucose dehydrogenase (GDH) activity were found to be required for glucose inhibition of prodigiosin production, including pyrroloquinoline quinone and ubiquinone biosynthetic genes. Upon assessing whether the enzymatic products of GDH activity were involved in the inhibitory effect, we observed that d-glucono-1,5-lactone and d-gluconic acid, but not d-gluconate, were able to inhibit prodigiosin production. These data support a model in which the oxidation of d-glucose by quinoprotein GDH initiates a reduction in pH that inhibits prodigiosin production through transcriptional control of the prodigiosin biosynthetic operon, providing new insight into the genetic pathways that control prodigiosin production. Strains generated in this report may be useful in large-scale production of secondary metabolites. PMID:22752173

  10. High-resolution X-ray spectroscopy of four active galaxies - Probing the intercloud medium

    NASA Astrophysics Data System (ADS)

    Lum, Kenneth S. K.; Canizares, Claude R.; Markert, Thomas H.; Arnaud, Keith A.

    1990-07-01

    The focal plane crystal spectrometer (FPCS) on the Einstein Observatory has been used to perform a high-resolution spectroscopic search for oxygen X-ray line emission from four active galaxies: Fairall 9, Mrk 421, Mrk 501, and PKS 0548 - 322. Specifically, O VIII Ly-alpha and Ly-beta, whose unredshifted energies are 653 and 775 eV, respectively, were sought. No narrow-line emission was detected within the energy bands searched. Upper limits are calculated on the line flux from these sources of 30 eV equivalent width and use a photoionization model to place corresponding upper limits on the densities of diffuse gas surrounding the active nuclei. The upper limits on gas density range from about 0.02-50/cu cm and probe various radial distances from the central source. This is the first time high-resolution X-ray spectroscopy has been used to place constraints on the intercloud medium in active galaxies.

  11. Serratia marcescens quinoprotein glucose dehydrogenase activity mediates medium acidification and inhibition of prodigiosin production by glucose.

    PubMed

    Fender, James E; Bender, Cody M; Stella, Nicholas A; Lahr, Roni M; Kalivoda, Eric J; Shanks, Robert M Q

    2012-09-01

    Serratia marcescens is a model organism for the study of secondary metabolites. The biologically active pigment prodigiosin (2-methyl-3-pentyl-6-methoxyprodiginine), like many other secondary metabolites, is inhibited by growth in glucose-rich medium. Whereas previous studies indicated that this inhibitory effect was pH dependent and did not require cyclic AMP (cAMP), there is no information on the genes involved in mediating this phenomenon. Here we used transposon mutagenesis to identify genes involved in the inhibition of prodigiosin by glucose. Multiple genetic loci involved in quinoprotein glucose dehydrogenase (GDH) activity were found to be required for glucose inhibition of prodigiosin production, including pyrroloquinoline quinone and ubiquinone biosynthetic genes. Upon assessing whether the enzymatic products of GDH activity were involved in the inhibitory effect, we observed that d-glucono-1,5-lactone and d-gluconic acid, but not d-gluconate, were able to inhibit prodigiosin production. These data support a model in which the oxidation of d-glucose by quinoprotein GDH initiates a reduction in pH that inhibits prodigiosin production through transcriptional control of the prodigiosin biosynthetic operon, providing new insight into the genetic pathways that control prodigiosin production. Strains generated in this report may be useful in large-scale production of secondary metabolites.

  12. Enhanced esterification activity through interfacial activation and cross-linked immobilization mechanism of Rhizopus oryzae lipase in a nonaqueous medium.

    PubMed

    Kartal, Funda

    2016-07-01

    Interfacial activation via surfactant (Tween 80, Triton X-100) treatment was conducted to improve the esterification activity of Rhizopus oryzae lipase that had undergone immobilization through cross-linked enzyme aggregates (CLEA®) technique. Surfactant pretreated immobilized enzymes exhibited better esterification activity compared to free and non-pretreated immobilized enzyme (Control CLEAs) since higher conversion rates were obtained within shorter times. The superiority of surfactant pretreated CLEAs, especially Tween 80 pretreated CLEAs (T 80 PT CLEAs), were clearly pronounced when longer alcohols were used as substrates. Conversion values exceeded 90% for octyl octanoate, oleyl octanoate and oleyl oleate synthesis with T 80 PT CLEAs whereas Control CLEAs and free enzyme showed no activity. Maximum conversions were achieved in the case equal molars of the substrates or in the case excess of the alcohol to acid in cyclohexane. In solvent free medium containing equal molars of substrates the conversion rates were 85% and 87% with T 80 PT CLEAs respectively for octyl octanoate and oleyl oleate within 2 hours. T 80 PT CLEAs showed 59% of its original activity after 7 consecutive usage for oleyl oleate synthesis. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:899-904, 2016. PMID:27111483

  13. Use of dyes in solid medium for screening ligninolytic activity of selective actinomycetes

    SciTech Connect

    Chahal, D.S.; Kluepfel, D.; Morosoli, R.

    1995-12-31

    Lignin, a three-dimensional biopolymer, not only encrusts the cellulose microfibrils in a sheath-like manner, but is also bonded physically and chemically to the plant polysaccharides. Unless the lignin is depolymerized, solubilized, or removed, the cellulose and hemicelluloses cannot be easily hydrolyzed by respective enzymes for their bioconversion into biofuels and chemicals. By now it has been established that lignin peroxidase (LiP) of white-rot fungus Phanerochaete chrysosporium is responsible for degradation of lignin. It has been reported that LiP is produced during secondary metabolism under carbon or nitrogen limitation by this organism. In literature, usually low yields (per unit volume) of LiP with P. chrysosporium have been reported. The reasons for low yields may be attributed to insufficient nitrogen in production media, which ultimately affects the synthesis of LiP protein. Therefore, it necessitated a search for an organism that can produce a ligninolytic enzyme system during its primary metabolism, without any effect of nitrogen limitation in the fermentation medium and without supply of extra oxygen to the cultures. Glenn and Gold were the first to report that decolorization of polymeric dyes in liquid cultures is related to the lignin degradation system. They demonstrated that like lignin degradation, the decolorization of polymeric dyes by the white-rot basidiomycete P. chrysosporium occurred during secondary metabolism, was suppressed in cultures grown in the presence of high levels of nitrogen, and was strongly dependent on the oxygen concentration in the cultures. The present study was undertaken to establish if certain dyes in solid media could be used to screen ligninolytic activity of selective actinomycetes during their primary metabolism without the limitation of nitrogen in the medium.

  14. Effects of chemically defined medium on early development of porcine embryos derived from parthenogenetic activation and cloning.

    PubMed

    Cao, Zubing; Sui, Liucai; Li, Yunsheng; Ji, Suofei; Zhang, Xiaorong; Zhang, Yunhai

    2012-08-01

    The present study was to investigate if a completely chemically defined medium (PZM-4) could support the early development of porcine embryos derived from parthenogenetic activation (PA) and cloning (somatic cell nuclear transfer, SCNT), and to lay the foundation for determining the physiological roles of certain supplements in this medium. Porcine embryos derived from PA and SCNT were cultured in media: PZM-3 (a chemically semi-defined medium), PZM-4 (a fully defined medium), and PZM-5 (an undefined medium). Early embryo development was observed. We found that the three medium groups (PZM-3, PZM-4 and PZM-5) exhibited no significant differences in cleavage rates of PA embryos (p > 0.05), while the blastocyst rate in PZM-3 was significantly higher than in PZM-4 and PZM-5 (78.9% vs. 36.0% and 52.3%) (p < 0.05). Moreover, total cell number per blastocyst in PZM-3 was clearly higher than in PZM-5 but similar to that in PZM-4. As for SCNT embryos, no significant differences were observed for the cleavage rates or the blastocyst rates among the three groups (p > 0.05). However, total cell number per blastocyst in PZM-3 was notably higher than in PZM-5, but was similar to that in PZM-4. In conclusion, our results suggested that the completely chemically defined medium PZM-4 can be used to efficiently support the early development of porcine PA and SCNT embryos.

  15. MHD SIMULATIONS OF ACTIVE GALACTIC NUCLEUS JETS IN A DYNAMIC GALAXY CLUSTER MEDIUM

    SciTech Connect

    Mendygral, P. J.; Jones, T. W.; Dolag, K.

    2012-05-10

    We present a pair of three-dimensional magnetohydrodynamical simulations of intermittent jets from a central active galactic nucleus (AGN) in a galaxy cluster extracted from a high-resolution cosmological simulation. The selected cluster was chosen as an apparently relatively relaxed system, not having undergone a major merger in almost 7 Gyr. Despite this characterization and history, the intracluster medium (ICM) contains quite active 'weather'. We explore the effects of this ICM weather on the morphological evolution of the AGN jets and lobes. The orientation of the jets is different in the two simulations so that they probe different aspects of the ICM structure and dynamics. We find that even for this cluster, which can be characterized as relaxed by an observational standard, the large-scale, bulk ICM motions can significantly distort the jets and lobes. Synthetic X-ray observations of the simulations show that the jets produce complex cavity systems, while synthetic radio observations reveal bending of the jets and lobes similar to wide-angle tail radio sources. The jets are cycled on and off with a 26 Myr period using a 50% duty cycle. This leads to morphological features similar to those in 'double-double' radio galaxies. While the jet and ICM magnetic fields are generally too weak in the simulations to play a major role in the dynamics, Maxwell stresses can still become locally significant.

  16. Iron stimulates plasma-activated medium-induced A549 cell injury

    PubMed Central

    Adachi, Tetsuo; Nonomura, Saho; Horiba, Minori; Hirayama, Tasuku; Kamiya, Tetsuro; Nagasawa, Hideko; Hara, Hirokazu

    2016-01-01

    Non-thermal atmospheric pressure plasma is applicable to living cells and has emerged as a novel technology for cancer therapy. Plasma has recently been shown to affect cells not only by direct irradiation, but also by indirect treatments with previously prepared plasma-activated medium (PAM). Iron is an indispensable element but is also potentially toxic because it generates the hydroxyl radical (•OH) in the presence of hydrogen peroxide (H2O2) via the Fenton reaction. The aim of the present study was to demonstrate the contribution of iron to PAM-induced A549 adenocarcinoma cell apoptosis. We detected the generation of •OH and elevation of intracellular ferrous ions in PAM-treated cells and found that they were inhibited by iron chelator. The elevations observed in ferrous ions may have been due to their release from the intracellular iron store, ferritin. Hydroxyl radical-induced DNA injury was followed by the activation of poly(ADP-ribose) polymerase-1, depletion of NAD+ and ATP, and elevations in intracellular Ca2+. The sensitivities of normal cells such as smooth muscle cells and keratinocytes to PAM were less than that of A549 cells. These results demonstrated that H2O2 in PAM and/or •OH generated in the presence of iron ions disturbed the mitochondrial-nuclear network in cancer cells. PMID:26865334

  17. Calculation of a mirror asymmetric effect in electron scattering from chiral targets. [in optically active medium

    NASA Technical Reports Server (NTRS)

    Rich, A.; Van House, J.; Hegstrom, R. A.

    1982-01-01

    A dynamical calculation is presented of the helicity induced in an initially unpolarized electron beam after elastic scattering from an optically active medium, a process analogous to the circular polarization induced in unpolarized light following Rayleigh scattering from chiral targets. The calculation is based on the bound helical electron model of a chiral molecule, according to which the major contribution to the helicity is provided by the perturbation of the electron bound state by the spin-orbit interaction of the bound electrons moving in the electric field of the molecular core. The net helicity acquired is found to depend directly on a molecular asymmetry factor and the square of the atomic number of the heaviest atom in an asymmetric environment. For the case of carbon, the induced helicity is on the order of 0.00001, which would account for its lack of observation in a recent experiment. Results may have implications for the origin of optical activity in biological molecules by the differential ionization of D and L isomers by beta-decay electrons.

  18. Medium-scale gravity wave activity in the thermosphere inferred from GOCE data

    NASA Astrophysics Data System (ADS)

    Garcia, Raphael F.; Bruinsma, Sean; Massarweh, Lotfi; Doornbos, Eelco

    2016-08-01

    This study is focused on the effect of solar flux conditions on the dynamics of gravity waves (GWs) in the thermosphere. Air density and crosswind in situ estimates from the Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) accelerometers are analyzed for the whole mission duration. The analysis is performed in the Fourier spectral domain averaging spectral results over periods of 2 months close to solstices. A new GW marker (called Cf3) is introduced here to characterize GWs activity under low, medium, and high solar flux conditions, showing a clear solar damping effect on GW activity. Most GW signal is found in a spectral range above 8 mHz in GOCE data, meaning a maximum horizontal wavelength of around 1000 km. The level of GW activity at GOCE altitude is strongly decreasing with increasing solar flux. Furthermore, a shift in the dominant frequency with solar flux conditions has been noted, leading to larger horizontal wavelengths (from 200 to 500 km) during high solar flux conditions. The correlation between air density variability and GW marker allows to identify most of the large-amplitude perturbations below 67° latitudes as due to GWs. The influence of correlated error sources, between air density and crosswinds, is discussed. Consistency of the spectral domain results is verified in the time domain with a global mapping of high-frequency air density perturbations along the GOCE orbit. This analysis shows a clear dependence with geomagnetic latitude with strong perturbations at magnetic poles and an extension to lower latitudes favored by low solar activity conditions. These results are consistent with previous Challenging Minisatellite Payload (CHAMP) data analysis and with general circulation models.

  19. Replacing Non-Active Video Gaming by Active Video Gaming to Prevent Excessive Weight Gain in Adolescents

    PubMed Central

    Simons, Monique; Brug, Johannes; Chinapaw, Mai J. M.; de Boer, Michiel; Seidell, Jaap; de Vet, Emely

    2015-01-01

    Objective The aim of the current study was to evaluate the effects of and adherence to an active video game promotion intervention on anthropometrics, sedentary screen time and consumption of sugar-sweetened beverages and snacks among non-active video gaming adolescents who primarily were of healthy weight. Methods We assigned 270 gaming (i.e. ≥2 hours/week non-active video game time) adolescents randomly to an intervention group (n = 140) (receiving active video games and encouragement to play) or a waiting-list control group (n = 130). BMI-SDS (SDS = adjusted for mean standard deviation score), waist circumference-SDS, hip circumference and sum of skinfolds were measured at baseline, at four and ten months follow-up (primary outcomes). Sedentary screen time, physical activity, consumption of sugar-sweetened beverages and snacks, and process measures (not at baseline) were assessed with self-reports at baseline, one, four and ten months follow-up. Multi-level-intention to treat-regression analyses were conducted. Results The control group decreased significantly more than the intervention group on BMI-SDS (β = 0.074, 95%CI: 0.008;0.14), and sum of skinfolds (β = 3.22, 95%CI: 0.27;6.17) (overall effects). The intervention group had a significantly higher decrease in self-reported non-active video game time (β = -1.76, 95%CI: -3.20;-0.32) and total sedentary screen time (Exp (β = 0.81, 95%CI: 0.74;0.88) than the control group (overall effects). The process evaluation showed that 14% of the adolescents played the Move video games every week ≥1 hour/week during the whole intervention period. Conclusions The active video game intervention did not result in lower values on anthropometrics in a group of ‘excessive’ non-active video gamers (mean ~ 14 hours/week) who primarily were of healthy weight compared to a control group throughout a ten-month-period. Even some effects in the unexpected direction were found, with the control group showing lower BMI

  20. Efficiency of the unstable resonator of a high-power laser with stochastic phase inhomogeneities in the active medium

    SciTech Connect

    Lobachev, V V; Strakhov, S Yu

    2006-02-28

    The specific features of operation of the unstable optical resonator of a large gas laser with an active medium containing stochastic phase inhomogeneities are considered. The output power of the laser, the Strehl number, the angular divergence and average far-field radiation intensity are studied as functions of the spatial scale and structure of random inhomogeneities of the refractive index of the active medium. Physical effects related to the deformation of the radiation pattern caused by a change in the spatial frequency of stochastic perturbations are analysed. (resonators, modes, beams)

  1. High-dose irradiation of bone chips preserves the in vitro activity of bone-conditioned medium.

    PubMed

    Sawada, Kosaku; Miron, Richard J; Leiser, Dominic; Caballé-Serrano, Jordi; Bosshardt, Dieter D; Schaller, Benoit; Buser, Daniel; Gruber, Reinhard

    2016-01-01

    Extracorporeal irradiation sterilizes resected tumor bone used as autografts in reconstruction surgery. Therapeutic irradiation is a standard technique in head and neck cancer therapy that aims to preserve organ function. Bone irradiation has a complex, mostly inhibitory, effect on remodeling and regeneration, although the underlying mechanisms are still not fully understood. It remains unclear if extracorporeal irradiation affects the paracrine-like activity of the corresponding autografts. We recently reported that bone-conditioned medium from autogenous bone chips contains a number of factors that might affect cell activity. In the present study, we investigated the effects of extracorporeal irradiation of porcine cortical bone chips on the activity of the corresponding bone-conditioned medium. The effects of bone-conditioned medium on the expressions of transforming growth factor-beta (TGF-β) target genes in oral fibroblasts were assessed. Bone-conditioned medium from bone chips exposed to a total radiation dose up to 120 Gy did not affect expressions of TGF-β target genes, including adrenomedullin, BTB/POZ domain-containing protein 11, proteoglycan 4, NADPH oxidase 4, and interleukin 11, in oral fibroblasts. In conclusion, bone irradiation does not alter the capability of the corresponding bone-conditioned medium to provoke a robust fibroblastic cell response in vitro. (J Oral Sci 58, 325-331, 2016). PMID:27665970

  2. Hydrous iron oxide modified diatomite as an active filtration medium for phosphate capture.

    PubMed

    Wang, Zhe; Lin, Yan; Wu, Deyi; Kong, Hainan

    2016-02-01

    A simple method to functionalize diatomite with hydrous iron oxide was attempted and its performance as a new active filtration material to remove and recover phosphate from water was investigated under varying solution conditions. The Langmuir phosphate adsorption capacity increased from 0.6 mgP/g for raw diatomite to 4.89, 14.71, 25.02 mgP/g for hydrous iron oxide modified diatomite (HIOMD), depending on the amount of iron loaded. Loading of hydrous iron oxide caused the increase in true and bulk density and a decline in filtration rate, but to a lesser extent. It was shown that the HIOMD product with suitable iron content could retain a good filtration performance with a greatly increased adsorption capacity for phosphate. The phosphate adsorption increased by decreasing pH and by increasing ionic strength at high pH levels. The adsorption process was interpreted by ligand exchange. Coexisting oxyanions of sulfate, nitrate, citrate, carbonate, silicate and humic acid showed different effects on phosphate fixation but it was presumed that their influence at their concentrations and pH levels commonly encountered in effluent or natural waters was limited, i.e., HIOMD had a reasonably good selectivity. Results in repeated adsorption, desorption and regeneration experiment showed that the adsorbed phosphate could be recovered and the material could be reused after regeneration. The column test showed that HIOMD could be potentially utilized as an adsorption filtration medium for phosphate removal and recovery from water.

  3. Superconducting quantum metamaterials as an active lasing medium: Effects of disorder

    NASA Astrophysics Data System (ADS)

    Koppenhöfer, Martin; Marthaler, Michael; Schön, Gerd

    2016-06-01

    A metamaterial formed by superconducting circuits or quantum dots can serve as an active lasing medium when coupled to a microwave resonator. For these artificial atoms, in contrast to real atoms, variations in their parameters cannot be avoided. In this paper, we examine the influence of disorder on such a multiatom lasing setup. We find that the lasing process evolves into a self-organized stationary state that is quite robust against disorder. The reason is that photons created by those atoms which are in or close to resonance with the resonator stimulate the emission also of more detuned atoms. Not only the number of photons grows with the number of atoms but also the width of the resonance as a function of the detuning. Similar properties are found for other types of disorder such as variations in the individual coupling. We present relations on how the allowed disorder scales with the number of atoms and confirm it by a numerical analysis. We also provide estimates for the sample-to-sample variations to be expected for setups with moderate numbers of atoms.

  4. Water activity and temperature effects on growth of Alternaria arborescens on tomato medium.

    PubMed

    Vaquera, Sandra; Patriarca, Andrea; Fernández Pinto, Virginia

    2014-08-18

    Alternaria arborescens is the causal agent of tomato stem canker, a disease frequently responsible of substantial economic losses. A. arborescens can produce several mycotoxins, such as alternariol, alternariol monomethyl ether and tenuazonic acid and phytotoxins such as the AAL toxins. The objective of this study was to determine the effect of water activity (aw, 0.950, 0.975, 0.995) and temperature (6, 15, 20, 25 and 30°C) on the germination and radial growth rate of A. arborescens on a synthetic tomato medium. Germination followed by growth was observed at all temperatures and aw levels analyzed. The shortest germination time (0.5 days) was observed at 0.995 aw, both at 25°C and at 30°C. The germination time increased with a reduction of aw and temperature. The highest growth rate was registered at 0.995 aw and 30°C (7.21 mm/day) while the lowest occurred at 0.950 aw and 6°C (0.52 mm/day), conditions at which the longest lag phase was observed (8 days). Growth rates increased with aw and temperature. Knowledge of the ecophysiology of the fungus in this substrate is necessary to formulate future strategies to prevent its development and evaluate the consumer health risk posed by potential exposure to the toxins. PMID:24964391

  5. Activity-dependent potentiation of recurrent inhibition: a mechanism for dynamic gain control in the siphon withdrawal reflex of Aplysia.

    PubMed

    Fischer, T M; Carew, T J

    1993-03-01

    The siphon withdrawal response (SWR) of Aplysia supports several forms of learning that are under both excitatory and inhibitory control. Here we examine the role of interneuronal processing on the regulation of siphon responses, with an emphasis on the role of inhibition. We focus on the recurrent circuit formed by the excitatory interneuron L29 and the inhibitory interneuron L30, and show that this circuit provides a mechanism for use-dependent regulation of excitatory input onto siphon motor neurons. We utilized a reduced preparation in which input to the SWR circuit was elicited by taps applied to the siphon; tap-evoked EPSPs were measured in LFS siphon motor neurons. We first show that L29 is an important source of excitatory input to LFS motor neurons: voltage-clamp inactivation of a single L29 (out of five) results in a significant reduction of tap-evoked EPSPs. Next, we demonstrate that direct intracellular activation of L29, surprisingly, produces transient inhibition of evoked input to motor neurons that lasts up to 40 sec. We then provide several lines of evidence that the mechanism of L29-induced inhibition is through the recruitment and potentiation of recurrent inhibition from L30: (1) L29 activation results in reduced tap-evoked responses of other (nonactivated) L29s; (2) direct activation of L30 mimics the inhibitory effects produced by L29 activation (LFS neurons receive no direct synaptic input from L30); and (3) the L30 IPSP is significantly potentiated as a result of its own activity, whether produced directly (by L30 activation) or indirectly (through L29 activation). This IPSP potentiation has the same time course as L29-induced inhibition of motor neuron responses. Thus activity-dependent potentiation of L30 transmission can inhibit motor neuron responses, in part through inactivation of the L29 interneuronal pool. Finally, we propose that L29-L30 interactions provide a mechanism for dynamic gain control in the SWR.

  6. PicoGreen dye as an active medium for plastic lasers

    NASA Astrophysics Data System (ADS)

    Pradeep, C.; Vallabhan, C. P. G.; Radhakrishnan, P.; Nampoori, V. P. N.

    2015-08-01

    Deoxyribonucleic acid lipid complex thin films are used as a host material for laser dyes. We tested PicoGreen dye, which is commonly used for the quantification of single and double stranded DNA, for its applicability as lasing medium. PicoGreen dye exhibits enhanced fluorescence on intercalation with DNA. This enormous fluorescence emission is amplified in a planar microcavity to achieve yellow lasing. Here the role of DNA is not only a host medium, but also as a fluorescence dequencher. With the obtained results we have ample reasons to propose PicoGreen dye as a lasing medium, which can lead to the development of DNA based bio-lasers.

  7. Medium chain fatty acids are selective peroxisome proliferator activated receptor (PPAR) γ activators and pan-PPAR partial agonists.

    PubMed

    Liberato, Marcelo Vizoná; Nascimento, Alessandro S; Ayers, Steven D; Lin, Jean Z; Cvoro, Aleksandra; Silveira, Rodrigo L; Martínez, Leandro; Souza, Paulo C T; Saidemberg, Daniel; Deng, Tuo; Amato, Angela Angelica; Togashi, Marie; Hsueh, Willa A; Phillips, Kevin; Palma, Mário Sérgio; Neves, Francisco A R; Skaf, Munir S; Webb, Paul; Polikarpov, Igor

    2012-01-01

    Thiazolidinediones (TZDs) act through peroxisome proliferator activated receptor (PPAR) γ to increase insulin sensitivity in type 2 diabetes (T2DM), but deleterious effects of these ligands mean that selective modulators with improved clinical profiles are needed. We obtained a crystal structure of PPARγ ligand binding domain (LBD) and found that the ligand binding pocket (LBP) is occupied by bacterial medium chain fatty acids (MCFAs). We verified that MCFAs (C8-C10) bind the PPARγ LBD in vitro and showed that they are low-potency partial agonists that display assay-specific actions relative to TZDs; they act as very weak partial agonists in transfections with PPARγ LBD, stronger partial agonists with full length PPARγ and exhibit full blockade of PPARγ phosphorylation by cyclin-dependent kinase 5 (cdk5), linked to reversal of adipose tissue insulin resistance. MCFAs that bind PPARγ also antagonize TZD-dependent adipogenesis in vitro. X-ray structure B-factor analysis and molecular dynamics (MD) simulations suggest that MCFAs weakly stabilize C-terminal activation helix (H) 12 relative to TZDs and this effect is highly dependent on chain length. By contrast, MCFAs preferentially stabilize the H2-H3/β-sheet region and the helix (H) 11-H12 loop relative to TZDs and we propose that MCFA assay-specific actions are linked to their unique binding mode and suggest that it may be possible to identify selective PPARγ modulators with useful clinical profiles among natural products.

  8. Peculiarities of the optimisation of optical resonators with regular small-scale inhomogeneities of an active medium

    SciTech Connect

    Lobachev, V V; Strakhov, S Yu

    2005-10-31

    The peculiarities of parametric optimisation of resonators containing small-scale inhomogeneities are considered. The two most important practical cases are studied in detail: an unstable resonator with small-scale phase inhomogeneities in the active medium and a stable resonator with small-scale amplitude modulations caused by the use of a perforated output mirror. (resonators)

  9. Gain-of-Function Mutations in Tnsc, an Atp-Dependent Transposition Protein That Activates the Bacterial Transposon Tn7

    PubMed Central

    Stellwagen, A. E.; Craig, N. L.

    1997-01-01

    The bacterial transposon Tn7 encodes five genes whose protein products are used in different combinations to direct transposition to different types of target sites. TnsABC+D directs transposition to a specific site in the Escherichia coli chromosome called attTn7, whereas TnsABC+E directs transposition to non-attTn7 sites. These transposition reactions can also recognize and avoid ``immune'' targets that already contain a copy of Tn7. TnsD and TnsE are required to activate TnsABC as well as to select a target site; no transposition occurs with wild-type TnsABC alone. Here, we describe the isolation of TnsC gain-of-function mutants that activate the TnsA+B transposase in the absence of TnsD or TnsE. Some of these TnsC mutants enable the TnsABC machinery to execute transposition without sacrificing its ability to discriminate between different types of targets. Other TnsC mutants appear to constitutively activate the TnsABC machinery so that it bypasses target signals. We also present experiments that suggest that target selection occurs early in the Tn7 transposition pathway in vivo: favorable attTn7 targets appear to promote the excision of Tn7 from the chromosome, whereas immune targets do not allow transposon excision to occur. This work supports the view that TnsC plays a central role in the evaluation and utilization of target DNAs. PMID:9055068

  10. Gain-of-function STAT1 mutations impair STAT3 activity in patients with chronic mucocutaneous candidiasis (CMC).

    PubMed

    Zheng, Jie; van de Veerdonk, Frank L; Crossland, Katherine L; Smeekens, Sanne P; Chan, Chun M; Al Shehri, Tariq; Abinun, Mario; Gennery, Andrew R; Mann, Jelena; Lendrem, Dennis W; Netea, Mihai G; Rowan, Andrew D; Lilic, Desa

    2015-10-01

    Signal transducer and activator of transcription 3 (STAT3) triggered production of Th-17 cytokines mediates protective immunity against fungi. Mutations affecting the STAT3/interleukin 17 (IL-17) pathway cause selective susceptibility to fungal (Candida) infections, a hallmark of chronic mucocutaneous candidiasis (CMC). In patients with autosomal dominant CMC, we and others previously reported defective Th17 responses and underlying gain-of-function (GOF) STAT1 mutations, but how this affects STAT3 function leading to decreased IL-17 is unclear. We also assessed how GOF-STAT1 mutations affect STAT3 activation, DNA binding, gene expression, cytokine production, and epigenetic modifications. We excluded impaired STAT3 phosphorylation, nuclear translocation, and sequestration of STAT3 into STAT1/STAT3 heterodimers and confirm significantly reduced transcription of STAT3-inducible genes (RORC/IL-17/IL-22/IL-10/c-Fos/SOCS3/c-Myc) as likely underlying mechanism. STAT binding to the high affinity sis-inducible element was intact but binding to an endogenous STAT3 DNA target was impaired. Reduced STAT3-dependent gene transcription was reversed by inhibiting STAT1 activation with fludarabine or enhancing histone, but not STAT1 or STAT3 acetylation with histone deacetylase (HDAC) inhibitors trichostatin A or ITF2357. Silencing HDAC1, HDAC2, and HDAC3 indicated a role for HDAC1 and 2. Reduced STAT3-dependent gene transcription underlies low Th-17 responses in GOF-STAT1 CMC, which can be reversed by inhibiting acetylation, offering novel targets for future therapies.

  11. Allele-specific silencing of mutant p53 attenuates dominant-negative and gain-of-function activities

    PubMed Central

    Iyer, Swathi V.; Parrales, Alejandro; Begani, Priya; Narkar, Akshay; Adhikari, Amit S.; Martinez, Luis A.; Iwakuma, Tomoo

    2016-01-01

    Many p53 hotspot mutants not only lose the transcriptional activity, but also show dominant-negative (DN) and oncogenic gain-of-function (GOF) activities. Increasing evidence indicates that knockdown of mutant p53 (mutp53) in cancer cells reduces their aggressive properties, suggesting that survival and proliferation of cancer cells are, at least partially, dependent on the presence of mutp53. However, these p53 siRNAs can downregulate both wild-type p53 (wtp53) and mutp53, which limits their therapeutic applications. In order to specifically deplete mutp53, we have developed allele-specific siRNAs against p53 hotspot mutants and validated their biological effects in the absence or presence of wtp53. First, the mutp53-specific siRNAs selectively reduced protein levels of matched p53 mutants with minimal reduction in wtp53 levels. Second, downregulation of mutp53 in cancer cells expressing a mutp53 alone (p53mut) resulted in significantly decreased cell proliferation and migration. Third, transfection of mutp53-specific siRNAs in cancer cells expressing both wtp53 and mutp53 also reduced cell proliferation and migration with increased transcripts of p53 downstream target genes, which became further profound when cells were treated with an MDM2 inhibitor Nutlin-3a or a chemotherapeutic agent doxorubicin. These results indicate that depletion of mutp53 by its specific siRNA restored endogenous wtp53 activity in cells expressing both wtp53 and mutp53. This is the first study demonstrating biological effects and therapeutic potential of allele-specific silencing of mutp53 by mutp53-specific siRNAs in cancer cells expressing both wtp53 and mutp53, thus providing a novel strategy towards targeted cancer therapies. PMID:26700961

  12. Fungicidal activity of fluconazole against Candida albicans in a synthetic vagina-simulative medium.

    PubMed

    Moosa, Mahomed-Yunus S; Sobel, Jack D; Elhalis, Hussain; Du, Wenjin; Akins, Robert A

    2004-01-01

    Fluconazole (FLZ) has emerged as a highly successful agent in the management of systemic infections of Candida. Cure rates for symptomatic candidiasis following single 150-mg FLZ dose therapy exceed 90%. In vitro, however, FLZ is fungistatic only in a narrow pH range and is not effective at vaginal pH, 4.2. This study evaluated the effect of FLZ on Candida albicans under in vitro conditions resembling the vaginal microenvironment, using vagina-simulative medium (VS). We found that FLZ was fungicidal for C. albicans in VS, but not in other media at the same pH, 4.2. In VS, FLZ was fungicidal at concentrations of >/=8 micro g/ml and reduced viability by greater than 99.9%. Analysis of the components of VS indicated that 17 mM acetic acid, a concentration achieved in the vagina, was responsible for the synergistic, fungicidal effect. This effect was not seen at neutral pH. Other substrates were not effective substitutes for acetic acid; however, short-chained carboxylic acids, glyoxylate and malonate, were effective. Most strains of C. albicans that were resistant to FLZ under standard conditions were killed by FLZ plus acetate. Other species of Candida were also killed, except C. krusei and C. glabrata. This study shows that FLZ has fungicidal activity for Candida species under in vitro conditions that mimic the vaginal microenvironment. This raises the possibility that FLZ may also have fungicidal effects during treatment of vaginal candidiasis. Elucidating the mechanism by which FLZ and acetate interact may disclose vulnerable pathways that could be exploited in drug development. PMID:14693534

  13. Indirect flat-panel detector with avalanche gain: Fundamental feasibility investigation for SHARP-AMFPI (scintillator HARP active matrix flat panel imager)

    SciTech Connect

    Zhao Wei; Li Dan; Reznik, Alla; Lui, B.J.M.; Hunt, D.C.; Rowlands, J.A.; Ohkawa, Yuji; Tanioka, Kenkichi

    2005-09-15

    An indirect flat-panel imager (FPI) with avalanche gain is being investigated for low-dose x-ray imaging. It is made by optically coupling a structured x-ray scintillator CsI(Tl) to an amorphous selenium (a-Se) avalanche photoconductor called HARP (high-gain avalanche rushing photoconductor). The final electronic image is read out using an active matrix array of thin film transistors (TFT). We call the proposed detector SHARP-AMFPI (scintillator HARP active matrix flat panel imager). The advantage of the SHARP-AMFPI is its programmable gain, which can be turned on during low dose fluoroscopy to overcome electronic noise, and turned off during high dose radiography to avoid pixel saturation. The purpose of this paper is to investigate the important design considerations for SHARP-AMFPI such as avalanche gain, which depends on both the thickness d{sub Se} and the applied electric field E{sub Se} of the HARP layer. To determine the optimal design parameter and operational conditions for HARP, we measured the E{sub Se} dependence of both avalanche gain and optical quantum efficiency of an 8 {mu}m HARP layer. The results were used in a physical model of HARP as well as a linear cascaded model of the FPI to determine the following x-ray imaging properties in both the avalanche and nonavalanche modes as a function of E{sub Se}: (1) total gain (which is the product of avalanche gain and optical quantum efficiency); (2) linearity; (3) dynamic range; (4) gain nonuniformity resulting from thickness nonuniformity; and (5) effects of direct x-ray interaction in HARP. Our results showed that a HARP layer thickness of 8 {mu}m can provide adequate avalanche gain and sufficient dynamic range for x-ray imaging applications to permit quantum limited operation over the range of exposures needed for radiography and fluoroscopy.

  14. Different effects of bifeprunox, aripiprazole, and haloperidol on body weight gain, food and water intake, and locomotor activity in rats.

    PubMed

    De Santis, Michael; Pan, Bo; Lian, Jiamei; Huang, Xu-Feng; Deng, Chao

    2014-09-01

    Following on the success of Aripiprazole with its high clinical efficacy and minimal side effects, further antipsychotic drugs (such as Bifeprunox) have been developed based on the same dopamine D2 partial agonist pharmacological profile as Aripiprazole. However clinical trials of Bifeprunox have found differing results to that of its predecessor, without the same significant clinical efficacy. This study has therefore investigated the different effects of 10 week treatment with Aripiprazole (0.75 mg/kg, 3 times per day), Bifeprunox (0.8 mg/kg, 3 times per day) and Haloperidol (0.1mg/kg, 3 times per day) on body weight gain, food and water intake, white fat mass, and 8 week treatment on locomotor activity. Treatment with Bifeprunox was found to significantly reduce all of the measured parameters except white fat mass compared to the control group. However, Aripiprazole and Haloperidol treatment reduced water intake compared to the control, without any significant effects on the other measured parameters. These findings further demonstrate the potential pharmacological differences between Aripiprazole and Bifeprunox, and identify potential weight loss side effects and increased anxiety behaviour with Bifeprunox treatment.

  15. Does Structured Quizzing with Process Specific Feedback Lead to Learning Gains in an Active Learning Geoscience Classroom?

    NASA Astrophysics Data System (ADS)

    Palsole, S.; Serpa, L. F.

    2013-12-01

    There is a great realization that efficient teaching in the geosciences has the potential to have far reaching effects in outreach to decision and policy makers (Herbert, 2006; Manduca & Mogk, 2006). This research in turn informs educators that the geosciences by the virtue of their highly integrative nature play an important role in serving as an entry point into STEM disciplines and helping developing a new cadre of geoscientists, scientists and a general population with an understanding of science. Keeping these goals in mind we set to design introductory geoscience courses for non-majors and majors that move away from the traditional lecture models which don't necessarily contribute well to knowledge building and retention ((Handelsman et al., 2007; Hake, 1997) to a blended active learning classroom where basic concepts and didactic information is acquired online via webquests, lecturettes and virtual field trips and the face to face portions of the class are focused on problem solving exercises. The traditional way to ensure that students are prepared for the in-class activity is to have the students take a quiz online to demonstrate basic competency. In the process of redesign, we decided to leverage the technology to build quizzes that are highly structured and map to a process (formation of divergent boundaries for example) or sets of earth processes that we needed the students to know before in-class activities. The quizzes can be taken multiple times and provide process specific feedback, thus serving as a heuristic to the students to ensure they have acquired the necessary competency. The heuristic quizzes were developed and deployed over a year with the student data driving the redesign process to ensure synchronicity. Preliminary data analysis indicates a positive correlation between higher student scores on in-class application exercises and time spent on the process quizzes. An assessment of learning gains also indicate a higher degree of self

  16. A Newly Identified CG301269 Improves Lipid and Glucose Metabolism Without Body Weight Gain Through Activation of Peroxisome Proliferator–Activated Receptor α and γ

    PubMed Central

    Jeong, Hyun Woo; Lee, Joo-Won; Kim, Woo Sik; Choe, Sung Sik; Kim, Kyung-Hee; Park, Ho Seon; Shin, Hyun Jung; Lee, Gha Young; Shin, Dongkyu; Lee, Hanjae; Lee, Jun Hee; Choi, Eun Bok; Lee, Hyeon Kyu; Chung, Heekyoung; Park, Seung Bum; Park, Kyong Soo; Kim, Hyo-Soo; Ro, Seonggu; Kim, Jae Bum

    2011-01-01

    OBJECTIVE Peroxisome proliferator–activated receptor (PPAR)-α/γ dual agonists have been developed to alleviate metabolic disorders. However, several PPARα/γ dual agonists are accompanied with unwanted side effects, including body weight gain, edema, and tissue failure. This study investigated the effects of a novel PPARα/γ dual agonist, CG301269, on metabolic disorders both in vitro and in vivo. RESEARCH DESIGN AND METHODS Function of CG301269 as a PPARα/γ dual agonist was assessed in vitro by luciferase reporter assay, mammalian one-hybrid assay, and analyses of PPAR target genes. In vitro profiles on fatty acid oxidation and inflammatory responses were acquired by fatty acid oxidation assay and quantitative (q)RT-PCR of proinflammatory genes. In vivo effect of CG301269 was examined in db/db mice. Total body weight and various tissue weights were measured, and hepatic lipid profiles were analyzed. Systemic glucose and insulin tolerance were measured, and the in vivo effect of CG301269 on metabolic genes and proinflammatory genes was examined by qRT-PCR. RESULTS CG301269 selectively stimulated the transcriptional activities of PPARα and PPARγ. CG301269 enhanced fatty acid oxidation in vitro and ameliorated insulin resistance and hyperlipidemia in vivo. In db/db mice, CG301269 reduced inflammatory responses and fatty liver, without body weight gain. CONCLUSIONS We demonstrate that CG301269 exhibits beneficial effects on glucose and lipid metabolism by simultaneous activation of both PPARα and PPARγ. Our data suggest that CG301269 would be a potential lead compound against obesity and related metabolic disorders. PMID:21270261

  17. Effects of novel auto-inducible medium on growth, activity and CO₂ capture capacity of Escherichia coli expressing carbonic anhydrase.

    PubMed

    Watson, Stuart K; Kan, Eunsung

    2015-10-01

    A glucose-based auto-inducible medium (glucose-AIM) has been developed to enhance both growth and expression of lac operon-linked carbonic anhydrase (CA) expression in a recombinant strain of Escherichia coli. When the E. coli expressing CA was grown on various media, the glucose-based auto-inducible medium (glucose AIM) resulted in a CA activity of 1022 mU OD(600 nm)(-1) mL(-1) at 24 h and a specific growth rate of 0.082 h(-1). The CA activity was four to fourteen times higher than those by LB-IPTG. The E. coli expressing CA grown on the glucose-AIM showed highest activity at pH8.5 while it kept high stability up to 40°C and an inlet CO2 concentration of 6%. These findings indicate that the glucose-AIM would be a cost-effective medium to support high cell growth, CA activity and stability for effective CO2 capture. PMID:26264623

  18. Second malignancies in patients with differentiated thyroid carcinoma treated with low and medium activities of radioactive I-131

    PubMed Central

    PICIU, DOINA; PESTEAN, CLAUDIU; BARBUS, ELENA; LARG, MARIA IULIA; PICIU, ANDRA

    2016-01-01

    Background and aim This study aimed at determining whether there is a risk regarding the development of second primary malignancies after patient exposure to the low and medium radioiodine activity used during the treatment of differentiated thyroid cancers (DTC). Methods Second primary malignancies that occurred after DTC were detected in 1,990 patients treated between 1970 and 2003. The mean long-term follow-up period was 182 months. Results Radioiodine I-131was administrated at a mean dose of 63.2 mCi. There were 93 patients with at least one second primary malignancy. The relative risk of development of second malignancy in DTC patients was increased (p<0.0001) for breast, uterine and ovarian cancers compared with the general population. Conclusions The overall risk concerning the development of second primary malignancies was related to the presence of DTC, but not to exposure to the low and medium activities of radioiodine administered as adjuvant therapy. PMID:27547058

  19. Net Gains

    ERIC Educational Resources Information Center

    Fielker, David

    2008-01-01

    The Easter conference 2008 had several activities which for the author raised the same questions on cube nets in some work with eight-year-olds some time ago. In this article, the author muses on some problems from the Easter conference regarding nets of shapes. (Contains 1 note.)

  20. Synthesis, antimicrobial activity and molecular docking of novel tetracyclic scaffolds incorporating a flavonoid framework with medium sized oxygen heterocycles.

    PubMed

    Dongamanti, Ashok; Aamate, Vikas Kumar; Devulapally, Mohan Gandhi; Gundu, Srinivas; Kotni, Meena Kumari; Manga, Vijjulatha; Balasubramanian, Sridhar; Ernala, Prasad

    2015-02-15

    A convenient approach for the synthesis of novel tetracyclic scaffolds incorporating a flavonoid framework with medium sized heterocyclic rings (eight-, nine-, ten- and eleven-membered rings) containing two oxygen atoms from flavonols through alkylation using different dibromoalkanes was described. The synthesized compounds were established based on the spectral data and X-ray crystal structure for 6c. The synthesized compounds were evaluated for their in vitro antimicrobial activity. Docking studies were carried out for most active two compounds 6f and 6i. PMID:25592711

  1. Synthesis, antimicrobial activity and molecular docking of novel tetracyclic scaffolds incorporating a flavonoid framework with medium sized oxygen heterocycles.

    PubMed

    Dongamanti, Ashok; Aamate, Vikas Kumar; Devulapally, Mohan Gandhi; Gundu, Srinivas; Kotni, Meena Kumari; Manga, Vijjulatha; Balasubramanian, Sridhar; Ernala, Prasad

    2015-02-15

    A convenient approach for the synthesis of novel tetracyclic scaffolds incorporating a flavonoid framework with medium sized heterocyclic rings (eight-, nine-, ten- and eleven-membered rings) containing two oxygen atoms from flavonols through alkylation using different dibromoalkanes was described. The synthesized compounds were established based on the spectral data and X-ray crystal structure for 6c. The synthesized compounds were evaluated for their in vitro antimicrobial activity. Docking studies were carried out for most active two compounds 6f and 6i.

  2. Creating a flipbook as a medium of instruction based on the research on activity test of kencur extract

    NASA Astrophysics Data System (ADS)

    Monika, Icha; Yeni, Laili Fitri; Ariyati, Eka

    2016-02-01

    This research aimed to reveal the validity of the flipbook as a medium of learning for the sub-material of environmental pollution in the tenth grade based on the results of the activity test of kencur (Kaempferia galanga) extract to control the growth of the Fusarium oxysporum fungus. The research consisted of two stages. First, testing the validity of the medium of flipbook through validation by seven assessors and analyzed based on the total average score of all aspects. Second, testing the activity of the kencur extract against the growth of Fusarium oxysporum by using the experimental method with 10 treatments and 3 repetitions which were analyzed using one-way analysis of variance (ANOVA) test. The making of the flipbook medium was done through the stages of analysis for the potential and problems, data collection, design, validation, and revision. The validation analysis on the flipbook received an average score of 3.7 and was valid to a certain extent, so it could be used in the teaching and learning process especially in the sub-material of environmental pollution in the tenth grade of the senior high school.

  3. The effect of medium on selected life-history traits in three clones of Lecane inermis (Rotifera) from activated sludge.

    PubMed

    Pajdak-Stós, Agnieszka; Kocerba, Wioleta; Fiałkowska, Edyta; Klimek, Beata; Fyda, Janusz

    2011-01-01

    We tested the effect of various culture media on life-history traits in three clones of the rotifer Lecane inermis, a potential bulking control agent. Four types of media were tested: a filtrate of activated sludge, mineral water, and each of these media enriched with molasses. The number of live and dead individuals and the number of amictic eggs were counted during the 14-day experiment, and the egg ratio (ER) and mortality rate were calculated. We found that the rotifers were well adapted to the changes in chemical composition of the medium and that the addition of molasses resulted in a significant increase in rotifer abundance. The highest ER was noted after two days, reaching a maximum of 4 eggs per female in treatments with filtrate and molasses-enriched filtrate. The life-history traits varied depending on the clone and the medium, but all of the clones were able to survive and proliferate, even after 14 days of starvation.

  4. Gain of function AMP-activated protein kinase γ3 mutation (AMPKγ3R200Q) in pig muscle increases glycogen storage regardless of AMPK activation.

    PubMed

    Scheffler, Tracy L; Park, Sungkwon; Roach, Peter J; Gerrard, David E

    2016-06-01

    Chronic activation of AMP-activated protein kinase (AMPK) increases glycogen content in skeletal muscle. Previously, we demonstrated that a mutation in the ryanodine receptor (RyR1(R615C)) blunts AMPK phosphorylation in longissimus muscle of pigs with a gain of function mutation in the AMPKγ3 subunit (AMPKγ3(R200Q)); this may decrease the glycogen storage capacity of AMPKγ3(R200Q) + RyR1(R615C) muscle. Therefore, our aim in this study was to utilize our pig model to understand how AMPKγ3(R200Q) and AMPK activation contribute to glycogen storage and metabolism in muscle. We selected and bred pigs in order to generate offspring with naturally occurring AMPKγ3(R200Q), RyR1(R615C), and AMPKγ3(R200Q) + RyR1(R615C) mutations, and also retained wild-type littermates (control). We assessed glycogen content and parameters of glycogen metabolism in longissimus muscle. Regardless of RyR1(R615C), AMPKγ3(R200Q) increased the glycogen content by approximately 70%. Activity of glycogen synthase (GS) without the allosteric activator glucose 6-phosphate (G6P) was decreased in AMPKγ3(R200Q) relative to all other genotypes, whereas both AMPKγ3(R200Q) and AMPKγ3(R200Q) + RyR1(R615C) muscle exhibited increased GS activity with G6P. Increased activity of GS with G6P was not associated with increased abundance of GS or hexokinase 2. However, AMPKγ3(R200Q) enhanced UDP-glucose pyrophosphorylase 2 (UGP2) expression approximately threefold. Although UGP2 is not generally considered a rate-limiting enzyme for glycogen synthesis, our model suggests that UGP2 plays an important role in increasing flux to glycogen synthase. Moreover, we have shown that the capacity for glycogen storage is more closely related to the AMPKγ3(R200Q) mutation than activity.

  5. Activation of the prefrontal cortex by unilateral transcranial direct current stimulation leads to an asymmetrical effect on risk preference in frames of gain and loss.

    PubMed

    Ye, Hang; Huang, Daqiang; Wang, Siqi; Zheng, Haoli; Luo, Jun; Chen, Shu

    2016-10-01

    Previous brain imaging and brain stimulation studies have suggested that the dorsolateral prefrontal cortex may be critical in regulating risk-taking behavior, although its specific causal effect on people's risk preference remains controversial. This paper studied the independent modulation of the activity of the right and left dorsolateral prefrontal cortex using various configurations of transcranial direct current stimulation. We designed a risk-measurement table and adopted a within-subject design to compare the same participant's risk preference before and after unilateral stimulation when presented with different frames of gain and loss. The results confirmed a hemispheric asymmetry and indicated that the right dorsolateral prefrontal cortex has an asymmetric effect on risk preference regarding frames of gain and loss. Enhancing the activity of the right dorsolateral prefrontal cortex significantly decreased the participants' degree of risk aversion in the gain frame, whereas it increased the participants' degree of risk aversion in the loss frame. Our findings provide important information regarding the impact of transcranial direct current stimulation on the risk preference of healthy participants. The effects observed in our experiment compared with those of previous studies provide further evidence of the effects of hemispheric and frame-dependent asymmetry. These findings may be helpful in understanding the neural basis of risk preference in humans, especially when faced with decisions involving possible gain or loss relative to the status quo.

  6. Activation of the prefrontal cortex by unilateral transcranial direct current stimulation leads to an asymmetrical effect on risk preference in frames of gain and loss.

    PubMed

    Ye, Hang; Huang, Daqiang; Wang, Siqi; Zheng, Haoli; Luo, Jun; Chen, Shu

    2016-10-01

    Previous brain imaging and brain stimulation studies have suggested that the dorsolateral prefrontal cortex may be critical in regulating risk-taking behavior, although its specific causal effect on people's risk preference remains controversial. This paper studied the independent modulation of the activity of the right and left dorsolateral prefrontal cortex using various configurations of transcranial direct current stimulation. We designed a risk-measurement table and adopted a within-subject design to compare the same participant's risk preference before and after unilateral stimulation when presented with different frames of gain and loss. The results confirmed a hemispheric asymmetry and indicated that the right dorsolateral prefrontal cortex has an asymmetric effect on risk preference regarding frames of gain and loss. Enhancing the activity of the right dorsolateral prefrontal cortex significantly decreased the participants' degree of risk aversion in the gain frame, whereas it increased the participants' degree of risk aversion in the loss frame. Our findings provide important information regarding the impact of transcranial direct current stimulation on the risk preference of healthy participants. The effects observed in our experiment compared with those of previous studies provide further evidence of the effects of hemispheric and frame-dependent asymmetry. These findings may be helpful in understanding the neural basis of risk preference in humans, especially when faced with decisions involving possible gain or loss relative to the status quo. PMID:27507423

  7. Measurements and simulations of the optical gain and anti-reflection coating modal reflectivity in quantum cascade lasers with multiple active region stacks

    NASA Astrophysics Data System (ADS)

    Bidaux, Y.; Terazzi, R.; Bismuto, A.; Gresch, T.; Blaser, S.; Muller, A.; Faist, J.

    2015-09-01

    We report spectrally resolved gain measurements and simulations for quantum cascade lasers (QCLs) composed of multiple heterogeneous stacks designed for broadband emission in the mid-infrared. The measurement method is first demonstrated on a reference single active region QCL based on a double-phonon resonance design emitting at 7.8 μm. It is then extended to a three-stack active region based on bound-to-continuum designs with a broadband emission range from 7.5 to 10.5 μm. A tight agreement is found with simulations based on a density matrix model. The latter implements exhaustive microscopic scattering and dephasing sources with virtually no fitting parameters. The quantitative agreement is furthermore assessed by measuring gain coefficients obtained by studying the threshold current dependence with the cavity length. These results are particularly relevant to understand fundamental gain mechanisms in complex semiconductor heterostructure QCLs and to move towards efficient gain engineering. Finally, the method is extended to the measurement of the modal reflectivity of an anti-reflection coating deposited on the front facet of the broadband QCL.

  8. Measurements and simulations of the optical gain and anti-reflection coating modal reflectivity in quantum cascade lasers with multiple active region stacks

    SciTech Connect

    Bidaux, Y.; Terazzi, R.; Bismuto, A.; Gresch, T.; Blaser, S.; Muller, A.; Faist, J.

    2015-09-07

    We report spectrally resolved gain measurements and simulations for quantum cascade lasers (QCLs) composed of multiple heterogeneous stacks designed for broadband emission in the mid-infrared. The measurement method is first demonstrated on a reference single active region QCL based on a double-phonon resonance design emitting at 7.8 μm. It is then extended to a three-stack active region based on bound-to-continuum designs with a broadband emission range from 7.5 to 10.5 μm. A tight agreement is found with simulations based on a density matrix model. The latter implements exhaustive microscopic scattering and dephasing sources with virtually no fitting parameters. The quantitative agreement is furthermore assessed by measuring gain coefficients obtained by studying the threshold current dependence with the cavity length. These results are particularly relevant to understand fundamental gain mechanisms in complex semiconductor heterostructure QCLs and to move towards efficient gain engineering. Finally, the method is extended to the measurement of the modal reflectivity of an anti-reflection coating deposited on the front facet of the broadband QCL.

  9. Thermally activated decomposition of (Ga,Mn)As thin layer at medium temperature post growth annealing

    NASA Astrophysics Data System (ADS)

    Melikhov, Y.; Konstantynov, P.; Domagala, J.; Sadowski, J.; Chernyshova, M.; Wojciechowski, T.; Syryanyy, Y.; Demchenko, I. N.

    2016-05-01

    The redistribution of Mn atoms in Ga1-xMnxAs layer during medium-temperature annealing, 250-450 oC, by Mn K-edge X-ray absorption fine structure (XAFS) recorded at ALBA facility, was studied. For this purpose Ga1-xMnxAs thin layer with x=0.01 was grown on AlAs buffer layer deposited on GaAs(100) substrate by molecular beam epitaxy (MBE) followed by annealing. The examined layer was detached from the substrate using a “lift-off” procedure in order to eliminate elastic scattering in XAFS spectra. Fourier transform analysis of experimentally obtained EXAFS spectra allowed to propose a model which describes a redistribution/diffusion of Mn atoms in the host matrix. Theoretical XANES spectra, simulated using multiple scattering formalism (FEFF code) with the support of density functional theory (WIEN2k code), qualitatively describe the features observed in the experimental fine structure.

  10. Quantitative structure activity relationships of some pyridine derivatives as corrosion inhibitors of steel in acidic medium.

    PubMed

    El Ashry, El Sayed H; El Nemr, Ahmed; Ragab, Safaa

    2012-03-01

    Quantum chemical calculations using the density functional theory (B3LYP/6-31G DFT) and semi-empirical AM1 methods were performed on ten pyridine derivatives used as corrosion inhibitors for mild steel in acidic medium to determine the relationship between molecular structure and their inhibition efficiencies. Quantum chemical parameters such as total negative charge (TNC) on the molecule, energy of highest occupied molecular orbital (E (HOMO)), energy of lowest unoccupied molecular orbital (E (LUMO)) and dipole moment (μ) as well as linear solvation energy terms, molecular volume (Vi) and dipolar-polarization (π) were correlated to corrosion inhibition efficiency of ten pyridine derivatives. A possible correlation between corrosion inhibition efficiencies and structural properties was searched to reduce the number of compounds to be selected for testing from a library of compounds. It was found that theoretical data support the experimental results. The results were used to predict the corrosion inhibition of 24 related pyridine derivatives.

  11. Reduction of methylene green by EDTA: a relation between dielectric constant of medium and activated state.

    PubMed

    Qamar, Noshab; Azmat, Rafia; Naz, Raheela

    2013-01-01

    Kinetics of an alkaline reduction of the methylene green with ethylenediaminetetraaceticacid (EDTA) as a role of dielectric constant of the medium with anecdotal ionic strength in a diverse solvent system (aqueous mixtures of methanol) (10-30%) was studied by measuring the specific rate constant of the reaction spectrophotometrically at λ (max) = 660nm. An effort has been made to give an elucidation of vital role of dielectric constant of the medium captivating into reflection of single sphere and double sphere complex in reaction assortment. This investigation leads to disclose that single sphere complex of the dye and reductant was found to be the most suitable complex existed in a varied organic solvent. The deviation of the theoretical values from experimental results for single sphere and double sphere complex model in the presence of an alkali and nitrate ions were justified through HPLC analysis. HPLC analysis recommended that a considerable amount of the dye degrades in the existence of nitrate ion and alkali and additional peaks which may be of by-product were obtained. This leads to confirm the non identical values of single sphere and double sphere model in the occurrence of nitrate and an alkali. Rate of deletion of color showed a linear liaison with respect to water content below 30% and temperature between 20-40(o)C whereas an increase in the concentration of organic solvent showed the inhibition of dye decoloration at given optimum condition. Therefore study was restricted up to 30% of methanol binary mixtures. A mechanism of reduction of dye has been proposed based on verdict.

  12. Order of Activity of Nitrogen, Iron Oxide, and FeNx Complexes towards Oxygen Reduction in Alkaline Medium.

    PubMed

    Zhu, Yansong; Zhang, Bingsen; Wang, Da-Wei; Su, Dang Sheng

    2015-12-01

    In alkaline medium, it seems that both metal-free and iron-containing carbon-based catalysts, such as nitrogen-doped nanocarbon materials, FeOx -doped carbon, and Fe/N/C catalysts, are active for the oxygen reduction reaction (ORR). However, the order of activity of these different active compositions has not been clearly determined. Herein, we synthesized nitrogen-doped carbon black (NCB), Fe3 O4 /CB, Fe3 O4 /NCB, and FeN4 /CB. Through the systematic study of the ORR catalytic activity of these four catalysts in alkaline solution, we confirmed the difference in the catalytic activity and catalytic mechanism for nitrogen, iron oxides, and Fe-N complexes, respectively. In metal-free NCB, nitrogen can improve the ORR catalytic activity with a four-electron pathway. Fe3 O4 /CB catalyst did not exhibit improved activity over that of NCB owing to the poor conductivity and spinel structure of Fe3 O4 . However, FeN4 coordination compounds as the active sites showed excellent ORR catalytic activity.

  13. The effects of acute stress exposure on striatal activity during Pavlovian conditioning with monetary gains and losses.

    PubMed

    Lewis, Andrea H; Porcelli, Anthony J; Delgado, Mauricio R

    2014-01-01

    Pavlovian conditioning involves the association of an inherently neutral stimulus with an appetitive or aversive outcome, such that the neutral stimulus itself acquires reinforcing properties. Across species, this type of learning has been shown to involve subcortical brain regions such as the striatum and the amygdala. It is less clear, however, how the neural circuitry involved in the acquisition of Pavlovian contingencies in humans, particularly in the striatum, is affected by acute stress. In the current study, we investigate the effect of acute stress exposure on Pavlovian conditioning using monetary reinforcers. Participants underwent a partial reinforcement conditioning procedure in which neutral stimuli were paired with high and low magnitude monetary gains and losses. A between-subjects design was used, such that half of the participants were exposed to cold stress while the remaining participants were exposed to a no stress control procedure. Cortisol measurements and subjective ratings were used as measures of stress. We observed an interaction between stress, valence, and magnitude in the ventral striatum, with the peak in the putamen. More specifically, the stress group exhibited an increased sensitivity to magnitude in the gain domain. This effect was driven by those participants who experienced a larger increase in circulating cortisol levels in response to the stress manipulation. Taken together, these results suggest that acute stress can lead to individual differences in circulating cortisol levels which influence the striatum during Pavlovian conditioning with monetary reinforcers.

  14. The effects of acute stress exposure on striatal activity during Pavlovian conditioning with monetary gains and losses

    PubMed Central

    Lewis, Andrea H.; Porcelli, Anthony J.; Delgado, Mauricio R.

    2014-01-01

    Pavlovian conditioning involves the association of an inherently neutral stimulus with an appetitive or aversive outcome, such that the neutral stimulus itself acquires reinforcing properties. Across species, this type of learning has been shown to involve subcortical brain regions such as the striatum and the amygdala. It is less clear, however, how the neural circuitry involved in the acquisition of Pavlovian contingencies in humans, particularly in the striatum, is affected by acute stress. In the current study, we investigate the effect of acute stress exposure on Pavlovian conditioning using monetary reinforcers. Participants underwent a partial reinforcement conditioning procedure in which neutral stimuli were paired with high and low magnitude monetary gains and losses. A between-subjects design was used, such that half of the participants were exposed to cold stress while the remaining participants were exposed to a no stress control procedure. Cortisol measurements and subjective ratings were used as measures of stress. We observed an interaction between stress, valence, and magnitude in the ventral striatum, with the peak in the putamen. More specifically, the stress group exhibited an increased sensitivity to magnitude in the gain domain. This effect was driven by those participants who experienced a larger increase in circulating cortisol levels in response to the stress manipulation. Taken together, these results suggest that acute stress can lead to individual differences in circulating cortisol levels which influence the striatum during Pavlovian conditioning with monetary reinforcers. PMID:24904331

  15. EEG oscillatory activity associated to monetary gain and loss signals in a learning task: effects of attentional impulsivity and learning ability.

    PubMed

    De Pascalis, Vilfredo; Varriale, Vincenzo; Rotonda, Marco

    2012-07-01

    This study investigated the influence of individual differences in attentional impulsivity (Att-Imp), learning ability, and learning practice on oscillatory activity and phase synchrony responses to monetary gain and loss signals during an instrumental-learning task in healthy women. We used a trial-by-trial wavelet-based time-frequency analysis of the electroencephalographic (EEG) signal to provide amplitude and inter-site phase synchrony measures from 30 electrodes in theta (4-8 Hz, 350-500 ms), alpha (8-12 Hz, 100-200 ms), beta (13-25 Hz, 100-200 ms), and gamma (30-40 Hz, 350-450 ms) time-frequency ranges. Oscillatory amplitude and inter-site phase synchrony were both greater following loss signals as compared to gain signals in theta, beta, and gamma frequency bands. Low Att-Imp subjects had higher theta activity within a 350-500 ms time window over frontocentral, and centroparietal sites than high Att-Imp subjects. Monetary gain signals elicited higher theta and gamma activities in high Att-Imp individuals and loss signals elicited higher activities to loss signals in low Att-Imp individuals. Good learners showed enhanced intrahemispheric theta synchrony between frontoparietal, and fronto-occipital sites to monetary loss compared to gain signals. In good learners, monetary loss produced an increase of gamma synchrony that enhanced in the second stage of learning. In low Att-Imp individuals, there was a reduction of theta synchrony during the second stage, as compared with the first stage of learning, between temporal, parietal and fronto-parietal brain regions. These findings may offer valuable clues to understand outcome processing, attentional impulsivity, and learning ability. We propose that the punishment-related theta and gamma waves play a leading role in learning process.

  16. Gain- and Loss-Related Brain Activation Are Associated with Information Search Differences in Risky Gambles: An fMRI and Eye-Tracking Study

    PubMed Central

    Trautner, Peter

    2016-01-01

    Abstract People differ in the way they approach and handle choices with unsure outcomes. In this study, we demonstrate that individual differences in the neural processing of gains and losses relates to attentional differences in the way individuals search for information in gambles. Fifty subjects participated in two independent experiments. Participants first completed an fMRI experiment involving financial gains and losses. Subsequently, they performed an eye-tracking experiment on binary choices between risky gambles, each displaying monetary outcomes and their respective probabilities. We find that individual differences in gain and loss processing relate to attention distribution. Individuals with a stronger reaction to gains in the ventromedial prefrontal cortex paid more attention to monetary amounts, while a stronger reaction in the ventral striatum to losses was correlated with an increased attention to probabilities. Reaction in the posterior cingulate cortex to losses was also found to correlate with an increased attention to probabilities. Our data show that individual differences in brain activity and differences in information search processes are closely linked. PMID:27679814

  17. Gain- and Loss-Related Brain Activation Are Associated with Information Search Differences in Risky Gambles: An fMRI and Eye-Tracking Study

    PubMed Central

    Trautner, Peter

    2016-01-01

    Abstract People differ in the way they approach and handle choices with unsure outcomes. In this study, we demonstrate that individual differences in the neural processing of gains and losses relates to attentional differences in the way individuals search for information in gambles. Fifty subjects participated in two independent experiments. Participants first completed an fMRI experiment involving financial gains and losses. Subsequently, they performed an eye-tracking experiment on binary choices between risky gambles, each displaying monetary outcomes and their respective probabilities. We find that individual differences in gain and loss processing relate to attention distribution. Individuals with a stronger reaction to gains in the ventromedial prefrontal cortex paid more attention to monetary amounts, while a stronger reaction in the ventral striatum to losses was correlated with an increased attention to probabilities. Reaction in the posterior cingulate cortex to losses was also found to correlate with an increased attention to probabilities. Our data show that individual differences in brain activity and differences in information search processes are closely linked.

  18. Activated macrophage conditioned medium: identification of the soluble factors inducing cytotoxicity and the L-arginine dependent effector mechanism.

    PubMed

    Amber, I J; Hibbs, J B; Parker, C J; Johnson, B B; Taintor, R R; Vavrin, Z

    1991-06-01

    Conditioned medium (CM) from cultures of cytotoxic activated macrophages causes inhibition of mitochondrial respiration, DNA synthesis, and aconitase activity in murine EMT-6 mammary adenocarcinoma cells by an L-arginine dependent effector mechanism. CM induces cytotoxicity and nitrite synthesis in EMT-6 cells in a dose dependent manner. We have identified the soluble factors in CM that induce cytotoxicity and synthesis of inorganic nitrogen oxides from L-arginine by EMT-6 cells. Using functional inhibition experiments, the activity of lipopolysaccharide (LPS), tumor necrosis factor alpha (TNF alpha), and interferon gamma (IFN gamma) in CM was investigated. The LPS inhibitor polymyxin B and TNF alpha antibody produced a modest decrease in nitrite production, while IFN gamma antibody markedly inhibited both nitrite production and cytostasis. Simultaneous treatment with polymyxin B, TNF alpha antibody, and IFN gamma antibody reduced EMT-6 cell nitrite production by 81%, and cytostasis by 74%. By Western blot, IFN gamma and TNF alpha were shown to be present in CM. When CM was subjected to hydrophobic interaction chromatography, a single peak of activity was eluted, and Western blot showed that the active fractions contained IFN gamma. Furthermore, IFN gamma antibody neutralized the activity in these chromatographic fractions. We conclude that induction of inorganic nitrogen oxide synthesis from L-arginine by the synergistic combination of IFN gamma, TNF alpha, and LPS accounts for most of the biologic activity of CM, and that IFN gamma is the major priming factor. PMID:1902865

  19. INEFFICIENT DRIVING OF BULK TURBULENCE BY ACTIVE GALACTIC NUCLEI IN A HYDRODYNAMIC MODEL OF THE INTRACLUSTER MEDIUM

    SciTech Connect

    Reynolds, Christopher S.; Balbus, Steven A.; Schekochihin, Alexander A.

    2015-12-10

    Central jetted active galactic nuclei (AGNs) appear to heat the core regions of the intracluster medium (ICM) in cooling-core galaxy clusters and groups, thereby preventing a cooling catastrophe. However, the physical mechanism(s) by which the directed flow of kinetic energy is thermalized throughout the ICM core remains unclear. We examine one widely discussed mechanism whereby the AGN induces subsonic turbulence in the ambient medium, the dissipation of which provides the ICM heat source. Through controlled inviscid three-dimensional hydrodynamic simulations, we verify that explosive AGN-like events can launch gravity waves (g-modes) into the ambient ICM, which in turn decays to volume-filling turbulence. In our model, however, this process is found to be inefficient, with less than 1% of the energy injected by the AGN activity actually ending up in the turbulence of the ambient ICM. This efficiency is an order of magnitude or more too small to explain the observations of AGN-feedback in galaxy clusters and groups with short central cooling times. Atmospheres in which the g-modes are strongly trapped/confined have an even lower efficiency since, in these models, the excitation of turbulence relies on the g-modes’ ability to escape from the center of the cluster into the bulk ICM. Our results suggest that, if AGN-induced turbulence is indeed the mechanism by which the AGN heats the ICM core, its driving may rely on physics beyond that captured in our ideal hydrodynamic model.

  20. Inefficient Driving of Bulk Turbulence By Active Galactic Nuclei in a Hydrodynamic Model of the Intracluster Medium

    NASA Astrophysics Data System (ADS)

    Reynolds, Christopher S.; Balbus, Steven A.; Schekochihin, Alexander A.

    2015-12-01

    Central jetted active galactic nuclei (AGNs) appear to heat the core regions of the intracluster medium (ICM) in cooling-core galaxy clusters and groups, thereby preventing a cooling catastrophe. However, the physical mechanism(s) by which the directed flow of kinetic energy is thermalized throughout the ICM core remains unclear. We examine one widely discussed mechanism whereby the AGN induces subsonic turbulence in the ambient medium, the dissipation of which provides the ICM heat source. Through controlled inviscid three-dimensional hydrodynamic simulations, we verify that explosive AGN-like events can launch gravity waves (g-modes) into the ambient ICM, which in turn decays to volume-filling turbulence. In our model, however, this process is found to be inefficient, with less than 1% of the energy injected by the AGN activity actually ending up in the turbulence of the ambient ICM. This efficiency is an order of magnitude or more too small to explain the observations of AGN-feedback in galaxy clusters and groups with short central cooling times. Atmospheres in which the g-modes are strongly trapped/confined have an even lower efficiency since, in these models, the excitation of turbulence relies on the g-modes’ ability to escape from the center of the cluster into the bulk ICM. Our results suggest that, if AGN-induced turbulence is indeed the mechanism by which the AGN heats the ICM core, its driving may rely on physics beyond that captured in our ideal hydrodynamic model.

  1. Pochonia chlamydosporia fungal activity in a solid medium and its crude extract against eggs of Ascaridia galli.

    PubMed

    Braga, F R; Araújo, J V; Araujo, J M; Frassy, L N; Tavela, A O; Soares, F E F; Carvalho, R O; Queiroz, L M; Queiroz, J H

    2012-09-01

    The present study aimed to evaluate the ovicidal activity (type 3 effect) of VC1 and VC4 isolates of Pochonia chlamydosporia in a solid medium and the action of a crude extract of P. chlamydosporia against eggs of Ascaridia galli. To evaluate ovicidal activity in culture medium, 1000 A. galli eggs were plated on Petri dishes containing 2% water-agar with grown fungal isolates (VC1 or VC4) and without fungus (control group) and were examined at 1, 3 and 5 days post-inoculation (assay A). Then, to test the action of crude extracts of P. chlamydosporia (VC1 or VC4), 500 eggs of A. galli were plated on Petri dishes of 4.5 cm diameter with 5 ml of fungal filtrate from each tested isolate. The control group consisted of 500 eggs of A. galli with 10 ml of distilled water on each Petri dish (assay B). Fungal isolates were effective (P < 0.01) at destroying these eggs, showing a type 3 effect at the studied intervals. On the other hand, the crude extract of isolates (VC1 or VC4) reduced the number of A. galli eggs in the treated group compared with the control group by 64.1% and 56.5%, respectively. The results of the present study show that P. chlamydosporia is effective at destroying eggs of A. galli and could therefore be used in the biological control of nematodes. PMID:21838959

  2. Active video games as a tool to prevent excessive weight gain in adolescents: rationale, design and methods of a randomized controlled trial

    PubMed Central

    2014-01-01

    Background Excessive body weight, low physical activity and excessive sedentary time in youth are major public health concerns. A new generation of video games, the ones that require physical activity to play the games –i.e. active games- may be a promising alternative to traditional non-active games to promote physical activity and reduce sedentary behaviors in youth. The aim of this manuscript is to describe the design of a study evaluating the effects of a family oriented active game intervention, incorporating several motivational elements, on anthropometrics and health behaviors in adolescents. Methods/Design The study is a randomized controlled trial (RCT), with non-active gaming adolescents aged 12 – 16 years old randomly allocated to a ten month intervention (receiving active games, as well as an encouragement to play) or a waiting-list control group (receiving active games after the intervention period). Primary outcomes are adolescents’ measured BMI-SDS (SDS = adjusted for mean standard deviation score), waist circumference-SDS, hip circumference and sum of skinfolds. Secondary outcomes are adolescents’ self-reported time spent playing active and non-active games, other sedentary activities and consumption of sugar-sweetened beverages. In addition, a process evaluation is conducted, assessing the sustainability of the active games, enjoyment, perceived competence, perceived barriers for active game play, game context, injuries from active game play, activity replacement and intention to continue playing the active games. Discussion This is the first adequately powered RCT including normal weight adolescents, evaluating a reasonably long period of provision of and exposure to active games. Next, strong elements are the incorporating motivational elements for active game play and a comprehensive process evaluation. This trial will provide evidence regarding the potential contribution of active games in prevention of excessive weight gain in

  3. Plasma-activated medium induces A549 cell injury via a spiral apoptotic cascade involving the mitochondrial-nuclear network.

    PubMed

    Adachi, Tetsuo; Tanaka, Hiromasa; Nonomura, Saho; Hara, Hirokazu; Kondo, Shin-ichi; Hori, Masaru

    2015-02-01

    Plasma medicine is a rapidly expanding new field of interdisciplinary research that combines physics, chemistry, biology, and medicine. Nonthermal atmospheric pressure plasma can be applied to living cells and tissues and has emerged as a novel technology for cancer therapy. Plasma has recently been shown to affect cells not only directly, but also by indirect treatment with previously prepared plasma-activated medium (PAM). The objective of this study was to demonstrate the inhibitory effects of PAM on A549 cell survival and elucidate the signaling mechanisms responsible for cell death. PAM maintained its ability to suppress cell viability for at least 1 week when stored at -80°C. The severity of PAM-triggered cell injury depended on the kind of culture medium used to prepare the PAM, especially that with or without pyruvate. Hydrogen peroxide (H2O2) and/or its derived or cooperating reactive oxygen species reduced the mitochondrial membrane potential, downregulated the expression of the antiapoptotic protein Bcl2, activated poly(ADP-ribose) polymerase-1, and released apoptosis-inducing factor from mitochondria with endoplasmic reticulum stress. However, the activation of caspase 3/7 and attenuation of cell viability by the addition of caspase inhibitor were not observed. The accumulation of adenine 5'-diphosphoribose as a product of the above reactions activated transient receptor potential melastatin 2, which elevated intracellular Ca(2+) levels and subsequently led to cell death. These results demonstrated that H2O2 and/or other reactive species in PAM disturbed the mitochondrial-nuclear network in cancer cells through a caspase-independent apoptotic pathway. Moreover, damage to the plasma membrane by H2O2-cooperating charged species not only induced apoptosis, but also increased its permeability to extracellular reactive species. These phenomena were also detected in PAM-treated HepG2 and MCF-7 cells. PMID:25433364

  4. Influence of the active nucleus on the multiphase interstellar medium in NGC 1068

    NASA Technical Reports Server (NTRS)

    Bland-Hawthorn, Jonathan; Weisheit, Jon; Cecil, Gerald; Sokolowski, James

    1993-01-01

    The luminous spiral NGC 1068 has now been imaged from x-ray to radio wavelengths at comparably high resolution (approximately less than 5 in. FWHM). The bolometric luminosity of this well-known Seyfert is shared almost equally between the active nucleus and an extended 'starburst' disk. In an ongoing study, we are investigating the relative importance of the nucleus and the disk in powering the wide range of energetic activity observed throughout the galaxy. Our detailed analysis brings together a wealth of data: ROSAT HRI observations, VLA lambda lambda 6-20 cu cm and OVRO interferometry, lambda lambda 0.4-10.8 micron imaging, and Fabry-Perot spectrophotometry.

  5. Students' Network Project Activities in the Context of the Information Educational Medium of Higher Education Institution

    ERIC Educational Resources Information Center

    Samerkhanova, Elvira K.; Krupoderova, Elena P.; Krupoderova, Klimentina R.; Bahtiyarova, Lyudmila N.; Ponachugin, Alexander V.

    2016-01-01

    The purpose of the research is justifying didactic possibilities of the use of network services for the organization of information for the learning environment of college, where students carry out their project activities, and where effective networking between students and teachers takes place. The authors consider didactic possibilities of…

  6. Comparative study of chromatographic medium-associated mass and potential antitumor activity loss with bioactive extracts.

    PubMed

    Datta, Sandipan; Zhou, Yu-Dong; Nagle, Dale G

    2013-04-26

    Natural product drug discovery programs often rely on the use of silica (Si) gel, reversed-phase media, or size-exclusion resins (e.g., RP-C18, Sephadex LH-20) for compound purification. The synthetic polymer-based sorbent Diaion HP20SS (cross-linked polystyrene matrix) is used as an alternative to prepare purified natural product libraries. To evaluate the impact of chromatographic media on the isolation of biologically active, yet chromatographically unstable natural products, Diaion HP20SS was evaluated side-by-side with normal-phase sorbents for irreversible binding of extract constituents and their effects on bioactivity. An array of chemically diverse natural product-rich extracts was selected as a test panel, and a cell-based reporter assay for hypoxia-inducible factor-1 (HIF-1) was employed to monitor potential change(s) in bioactivity. Silica gel caused significant irreversible binding of three out of 10 extracts. Curcuma longa, Saururus cernuus, and Citrus reticulata extracts showed decreased HIF-1 inhibitory activity after elution through Si gel. An additional nonpolar column wash of HP20SS with EtOAc retained considerable bioactivities of active extracts. In general, Si gel produced the greatest loss of bioactivity. However, HP20SS elution reduced significantly HIF-1 inhibitory activity of certain extracts (e.g., Asimina triloba). PMID:23441686

  7. Mechanism of dark decomposition of iodine donor in the active medium of a pulsed chemical oxygen - iodine laser

    SciTech Connect

    Andreeva, Tamara L; Kuznetsova, S V; Maslov, A I; Sorokin, Vadim N

    2002-06-30

    A scheme is proposed that describes the dark decomposition of iodide - the donor of iodine - and the relaxation of singlet oxygen in the chlorine-containing active medium of a pulsed chemical oxygen - iodine laser (COIL). For typical compositions of the active media of pulsed COILs utilising CH{sub 3}I molecules as iodine donors, a branching chain reaction of the CH{sub 3}I decomposition accompanied by the efficient dissipation of singlet oxygen is shown to develop even at the stage of filling the active volume. In the active media with CF{sub 3}I as the donor, a similar chain reaction is retarded due to the decay of CF{sub 3} radicals upon recombination with oxygen. The validity of this mechanism is confirmed by a rather good agreement between the results of calculations and the available experimental data. The chain decomposition of alkyliodides accompanied by an avalanche production of iodine atoms represents a new way of efficient chemical production of iodine for a COIL. (active media)

  8. Gain and losses in THz quantum cascade laser with metal-metal waveguide.

    PubMed

    Martl, Michael; Darmo, Juraj; Deutsch, Christoph; Brandstetter, Martin; Andrews, Aaron Maxwell; Klang, Pavel; Strasser, Gottfried; Unterrainer, Karl

    2011-01-17

    Coupling of broadband terahertz pulses into metal-metal terahertz quantum cascade lasers is presented. Mode matched terahertz transients are generated on the quantum cascade laser facet of subwavelength dimension. This method provides a full overlap of optical mode and active laser medium. A longitudinal optical-phonon depletion based active region design is investigated in a coupled cavity configuration. Modulation experiments reveal spectral gain and (broadband) losses. The observed gain shows high dynamic behavior when switching from loss to gain around threshold and is clamped at total laser losses.

  9. Effects of drying on nitrification activity in zeoponic medium used for long-term space missions

    NASA Technical Reports Server (NTRS)

    McGilloway, R. L.; Weaver, R. W.

    2004-01-01

    One component of a proposed life support system is the use of zeoponic substrates, which slowly release NH4+ into "soil" solution, for the production of plants. Nitrifying bacteria that convert NH4+ to NO3- are among the important microbial components of these systems. Survival of nitrifying bacteria in dry zeoponic substrates is needed, because the substrate would likely be stored in an air-dry state between croppings. Substrate was enriched for nitrifying bacteria and allowed to air-dry in a laminar flow hood. Stored substrate was analyzed for nitrifier survivability by measuring nitrifier activity at the beginning, 3 days, 1, 2, and 3 weeks. After rewetting, activity was approximately 9 micrograms N g-1 h-1 regardless of storage time. Nitrification rates did not decrease during storage. It seems unlikely that drying between plantings would result in practical reductions in nitrification, and reinoculation with nitrifying bacteria would not be necessary.

  10. Investigating Informatics Activity, Control, and Training Needs in Large, Medium, and Small Health Departments

    PubMed Central

    Arnold, Ryan; Yang, Biru

    2016-01-01

    Introduction: A recent National Association of City & County Health Officials survey shed light on informatics workforce development needs. Local health departments (LHDs) of various jurisdictional sizes and control over informatics may differ on training needs and activity. Understanding the precise nature of this variation will allow stakeholders to appropriately develop workforce development tools to advance the field. Objective: To understand the informatics training needs for LHDs of different jurisdictional sizes. Methods: Survey responses were analyzed by comparing training needs and LHD population size. Results: Larger health departments consistently reported having greater informatics-related capacity and informatics-related training needs. Quantitative data analysis was identified as a primary need for large LHDs. In addition, LHDs that report higher control of informatics/information technology were able to engage in more informatics activities. Conclusion: Smaller LHDs need additional resources to improve informatics-related capacity and engagement with the field. PMID:27684621

  11. Generation of unipolar optical pulses in a Raman-active medium

    NASA Astrophysics Data System (ADS)

    Arkhipov, R. M.; Arkhipov, M. V.; Belov, P. A.; Tolmachev, Yu A.; Babushkin, I.

    2016-04-01

    Response of a Raman-active media (RAM) to the excitation by a series of ultrashort (few-cycle) optical pulses propagating at a superluminal velocity is studied theoretically. It is shown that under certain conditions rectangular unipolar pulses (video-pulses) can be generated as the RAM response. The duration, shape and amplitude of these video-pulses can be widely tuned by modifying the pump pulse parameters.

  12. Unstable resonators with a distributed focusing gain.

    PubMed

    Ferguson, T R

    1994-08-20

    The geometrical optics approximation is used to form a model of axisymmetric unstable resonators having distributed focus, gain, and loss. A tapered reflectivity feedback mirror is included. The rate equations for propagation through the focusing gain medium are derived. A unique grid is found for propagation without interpolation along eigenrays in each direction. Numerical examples show the effects of distributed gain and focus on the axial and transverse intensity distributions. PMID:20935986

  13. Lasing properties of active medium based on sulforhodamine 101 incorporated into commercial polyurethane compound

    SciTech Connect

    Nikolaev, S V; Pozhar, V V; Dzyubenko, M I

    2011-01-24

    The lasing properties of polymer matrices based on commercial polyurethane compound activated by sulforhodamine 101 dye are studied. Lasing with an efficiency of 26 % and pulse energy of 76 mJ is obtained using microsecond transverse pumping at a wavelength of 587 nm. The service life (time of operation to a decrease in the output energy by 50 % upon excitation by 0.3 J cm{sup -2} pulses) amounts to 2500 pulses. A particular attention is given to the bichromatic lasing spectra of the samples tested. Based on the experimental data a model explaining the two-band emission spectrum is proposed and discussed. (lasers and amplifiers)

  14. The aqueous-polyelectrolyte dye solution as an active laser medium

    SciTech Connect

    Akimov, A I; Saletskii, A M

    2000-11-30

    The spectral, luminescent, and lasing properties of aqueous solutions of a cationic dye rhodamine 6G with additions of anion polyelectrolytes - polyacrylic and polymethacrylic acids - are studied. It is found that the energy and spectral properties of lasing of these solutions depend on the ratio of concentrations of polyelectrolyte and molecules. It is also found that the lasing parameters of aqueous-polyelectrolyte dye solutions can be controlled by changing the structure of the molecular system. The variation in the structure of aqueous-polyelectrolyte dye solutions of rhodamine 6G resulted in an almost five-fold increase in the lasing efficiency compared to that in aqueous dye solutions. (lasers, active media)

  15. Effect of betulin-containing extract from birch tree bark on α-amylase activity in vitro and on weight gain of broiler chickens in vivo.

    PubMed

    Ilyina, Anna; Arredondo-Valdés, Roberto; Farkhutdinov, Salavat; Segura-Ceniceros, Elda Patricia; Martínez-Hernández, José Luis; Zaynullin, Radik; Kunakova, Rayhana

    2014-03-01

    In vitro effect of betulin-containing extract from Betula pendula Roth. bark on alpha-amylase activity was studied, the kinetic mechanism of interaction was proposed and in vivo effect of betulin-containing extract on weight gain and meat quality of broiler chickens was evaluated. The highest level of inhibitory activity (20%) was detected in extract concentration of 1,000 mg/L. Increased extract concentration did not lead to increased enzyme inhibition. Using Dixon and Cornish-Bowden coordinates, the competitive mechanism of inhibition was demonstrated. Calculated kinetic parameters were: Km equal to 0.6 mg/mL, Vmax equal to 2.6 and 2.1 mM/min from Lineweaver-Burk and Dixon coordinates, respectively and Ki equal to 3,670 ± 230 mg/mL. The partial inhibition of enzyme indicates the existence of low concentration of active inhibitory form, which reaches saturation level with increased extract concentration in applied suspension. Therefore, Ki has an apparent constant character. This partial inhibition of amylase activity observed in in vitro assay did not affect weight gain and meat quality of broiler chickens during in vivo assay. Rather, the tendency to increase the weight of edible parts and muscles compared to diet without additive suggests that the extract may be a potential food additive in poultry farming. Additionally, it could be a source for further pharmaceutical and pharmacological research.

  16. Influence of liquid medium on the activity of a low-alpha Fischer-Tropsch catalyst

    SciTech Connect

    Gormley, R.J.; Zarochak, M.F.; Deffenbaugh, P.W.; Rao, K.R.P.M.

    1995-12-31

    The purpose of this research was to measure activity, selectivity, and the maintenance of these properties in slurry autoclave experiments with a Fischer-Tropsch (FT) catalyst that was used in the {open_quotes}FT II{close_quotes} bubble-column test, conducted at the Alternative Fuels Development Unit (AFDU) at LaPorte, Texas during May 1994. The catalyst contained iron, copper, and potassium and was formulated to produce mainly hydrocarbons in the gasoline range with lesser production of diesel-range products and wax. The probability of chain growth was thus deliberately kept low. Principal goals of the autoclave work have been to find the true activity of this catalyst in a stirred tank reactor, unhindered by heat or mass transfer effects, and to obtain a steady conversion and selectivity over the approximately 15 days of each test. Slurry autoclave testing of the catalyst in heavier waxes also allows insight into operation of larger slurry bubble column reactors. The stability of reactor operation in these experiments, particularly at loadings exceeding 20 weight %, suggests the likely stability of operations on a larger scale.

  17. More gain less pain: balance control learning shifts the activation patterns of leg and neck muscles and increases muscular parsimony.

    PubMed

    Iodice, Pierpaolo; Cesinaro, Stefano; Romani, Gian Luca; Pezzulo, Giovanni

    2015-07-01

    Athletes such as skaters or surfers maintain their balance on very unstable platforms. Remarkably, the most skilled athletes seem to execute these feats almost effortlessly. However, the dynamics that lead to the acquisition of a defined and efficient postural strategy are incompletely known. To understand the posture reorganization process due to learning and expertise, we trained twelve participants in a demanding balance/posture maintenance task for 4 months and measured their muscular activity before and after a (predictable) disturbance cued by an auditory signal. The balance training determined significant delays in the latency of participants' muscular activity: from largely anticipatory muscular activity (prior to training) to a mixed anticipatory-compensatory control strategy (after training). After training, the onset of activation was delayed for all muscles, and the sequence of activation systematically reflected the muscle position in the body from top to bottom: neck/upper body muscles were recruited first and in an anticipatory fashion, whereas leg muscles were recruited after the disturbance onset, producing compensatory adjustments. The resulting control strategy includes a mixture of anticipatory and compensatory postural adjustments, with a systematic sequence of muscular activation reflecting the different demands of neck and leg muscles. Our results suggest that subjects learned the precise timing of the disturbance onset and used this information to deploy postural adjustments just-in-time and to transfer at least part of the control of posture from anticipatory to less-demanding feedback-based strategies. In turn, this strategy shift increases the cost-efficiency of muscular activity, which is a key signature of skilled performance.

  18. Medium-frequency impulsive-thrust-activated liquid hydrogen reorientation with Geyser

    NASA Technical Reports Server (NTRS)

    Hung, R. J.; Shyu, K. L.

    1992-01-01

    Efficient technique are studied for accomplishing propellant resettling through the minimization of propellant usage through impulsive thrust. A comparison between the use of constant-thrust and impulsive-thrust accelerations for the activation of propellant resettlement shows that impulsive thrust is superior to constant thrust for liquid reorientation in a reduced-gravity environment. This study shows that when impulsive thrust with 0.1-1.0-, and 10-Hz frequencies for liquid-fill levels in the range between 30-80 percent is considered, the selection of 1.0-Hz-frequency impulsive thrust over the other frequency ranges of impulsive thrust is the optimum. Characteristics of the slosh waves excited during the course of 1.0-Hz-frequency impulsive-thrust liquid reorientation were also analyzed.

  19. Remembering with gains and losses: effects of monetary reward and punishment on successful encoding activation of source memories.

    PubMed

    Shigemune, Yayoi; Tsukiura, Takashi; Kambara, Toshimune; Kawashima, Ryuta

    2014-05-01

    The motivation of getting rewards or avoiding punishments reinforces learning behaviors. Although the neural mechanisms underlying the effect of rewards on episodic memory have been demonstrated, there is little evidence of the effect of punishments on this memory. Our functional magnetic resonance imaging (fMRI) study investigated the effects of monetary rewards and punishments on activation during the encoding of source memories. During encoding, participants memorized words (item) and locations of presented words (source) under 3 conditions (Reward, Punishment, and Control). During retrieval, participants retrieved item and source memories of the words and were rewarded or penalized according to their performance. Source memories encoded with rewards or punishments were remembered better than those without such encoding. fMRI data demonstrated that the ventral tegmental area and substantia nigra and nucleus accumbens activations reflected both the processes of reward and punishment, whereas insular activation increased as a linear function of punishment. Activation in the hippocampus and parahippocampal cortex predicted subsequent retrieval success of source memories. Additionally, correlations between these reward/punishment-related regions and the hippocampus were significant. The successful encoding of source memories could be enhanced by punishments and rewards, and interactions between reward/punishment-related regions and memory-related regions could contribute to memory enhancement by reward and/or punishment.

  20. Proton Reaction Data Library for Nuclear Activation (Medium Energy Nuclear Data Library.)

    2002-03-01

    Version 00 GROUPXS does file handling and processing of the double-differential continuum-emission cross sections stored in the new MF6 format of ENDF/VI. It treats the energy-angle data that are supposed to be represented by a Legendre-polynomial expansion in the center-of-mass system and can do the following: (1) Conversion of MF6 data from center-of-mass system to the laboratory system, with the possibility to continue the calculation with the options (2), (3), and (4). (2) Conversion ofmore » Legendre-polynomial representation into point-wise angular data, in MF6 format. (3) Conversion of data from MF6 into MF4 + MF5 (ENDF-V). (4) Calculation of group constants, scattering matrices and transfer matrices for arbitrary group structures with a fusion micro-flux weighting spectrum (PN-approximation). The code treats only continuum reaction types that are stored in the MF6 format with the restrictions as specified for the European Fusion File (EFF1). These restrictions are not inconvenient for the purpose of fusion neutronics calculations and they facilitate relatively simple processing . This neutron reaction data library can be used for nuclear activation and transmutation applications at energies up to 100 MeV.« less

  1. Liquid crystals with patterned molecular orientation as an electrolytic active medium.

    PubMed

    Peng, Chenhui; Guo, Yubing; Conklin, Christopher; Viñals, Jorge; Shiyanovskii, Sergij V; Wei, Qi-Huo; Lavrentovich, Oleg D

    2015-11-01

    Transport of fluids and particles at the microscale is an important theme in both fundamental and applied science. One of the most successful approaches is to use an electric field, which requires the system to carry or induce electric charges. We describe a versatile approach to generate electrokinetic flows by using a liquid crystal (LC) with surface-patterned molecular orientation as an electrolyte. The surface patterning is produced by photoalignment. In the presence of an electric field, the spatially varying orientation induces space charges that trigger flows of the LC. The active patterned LC electrolyte converts the electric energy into the LC flows and transport of embedded particles of any type (fluid, solid, gaseous) along a predesigned trajectory, posing no limitation on the electric nature (charge, polarizability) of these particles and interfaces. The patterned LC electrolyte exhibits a quadratic field dependence of the flow velocities; it induces persistent vortices of controllable rotation speed and direction that are quintessential for micro- and nanoscale mixing applications. PMID:26651712

  2. Chloroplast ultra structure, photosynthesis and enzyme activities in regenerated plants of Stevia rebaudiana (Bert.) Bertoni as influenced by copper sulphate in the medium.

    PubMed

    Jain, Pourvi; Kachhwaha, Sumita; Kothari, S L

    2014-09-01

    Stevia rebaudiana (Bert.) Bertoni is an important medicinal plant used as noncaloric commercial sweetener. Plants regenerated with higher levels of copper sulphate in the medium exhibited enhanced activity of peroxidase and polyphenoloxidase (PPO) enzymes. Transmission electron microscopy (TEM) revealed increase in size and number of electron dense inclusions in the chloroplasts of plants regenerated at optimised level of copper sulphate (0.5 microM) in the medium. There was decrease in chlorogenic acid (CGA) content. Chl-a-fluorescence transient pattern (OJIP) showed that the photosynthesis process was more efficient at 0.5 microM CuSO4 in the medium.

  3. Low-noise and high-gain Brillouin optical amplifier for narrowband active optical filtering based on a pump-to-signal optoelectronic tracking.

    PubMed

    Souidi, Yahia; Taleb, Fethallah; Zheng, Junbo; Lee, Min Won; Du Burck, Frédéric; Roncin, Vincent

    2016-01-10

    We implement and characterize an optical narrowband amplifier based on stimulated Brillouin scattering with pump-to-signal relative frequency fluctuations overcome thanks to an active pump tracking. We achieve a precise characterization of this amplifier in terms of gain and noise degradation (noise figure). The performances of this stable selective amplification are compared to those of a conventional erbium-doped fiber amplifier in order to highlight the interest of the Brillouin amplification solution for active narrow optical filtering with a bandpass of 10 MHz. Thanks to the simple optoelectronic pump-to-signal tracking, the Brillouin active filter appears as a stable and reliable solution for narrowband optical processing in the coherent optical communication context and optical sensor applications. PMID:26835759

  4. Cardiovascular responses to peripheral chemoreflex activation and comparison of different methods to evaluate baroreflex gain in conscious mice using telemetry.

    PubMed

    Braga, Valdir A; Burmeister, Melissa A; Sharma, Ram V; Davisson, Robin L

    2008-10-01

    Peripheral chemoreceptors located in the carotid bodies are the primary sensors of systemic hypoxia. Although the pattern of responses elicited by peripheral chemoreceptor activation is well established in rats, lambs, and rabbits, the cardiovascular responses to peripheral chemoreflex activation in conscious mice have not been delineated. Here we report that stimulation of peripheral chemoreceptors by potassium cyanide (KCN) in conscious mice elicits a unique biphasic response in blood pressure that is characterized by an initial and robust rise followed by a decrease in blood pressure, which is accompanied by a marked reduction in heart rate. The depressor and bradycardic responses to KCN were abolished by muscarinic receptor blockade with atropine, and the pressor response was abolished by alpha-adrenergic receptor blockade with prazosin, suggesting that vagal and sympathetic drive to the heart and sympathetic drive to the vasculature mediate these cardiovascular responses. These studies characterized the chemoreflex in conscious mice and established the reliability of using them for studying hypoxia-related diseases such as obstructive sleep apnea. In another series of experiments, two methods for analyzing baroreflex sensitivity were compared: the classical pharmacological approach using phenylephrine and sodium nitroprusside (i.e., the Oxford technique) or the sequence method for analyzing spontaneous baroreflex activity. Our findings indicate that both methods are reliable, and the sequence method certainly has its benefits as a predictive tool in the context of long-term noninvasive studies using telemetry. However, for absolute determination of baroreflex function, analysis of spontaneous baroreflex activity should be complemented by the classical pharmacological method. PMID:18667715

  5. Collapsible high gain antenna

    NASA Technical Reports Server (NTRS)

    Cribb, H. E. (Inventor)

    1973-01-01

    A lightweight small high gain antenna which is capable of being packaged in a collapsed form and automatically expanded when in use is described. The antenna includes a cylindrical housing having a rod with a piston adjacent to one end extending through it. Attached to the outer end of the rod in a normally collapsed state is a helical wire coil. When the gas producing means is activated the piston and rod are shifted outwardly to expand the wire coil. A latch is provided for holding the helical coil in the expanded position.

  6. Histone deacetylase inhibitors stimulate the susceptibility of A549 cells to a plasma-activated medium treatment.

    PubMed

    Adachi, Tetsuo; Kano, Ayame; Nonomura, Saho; Kamiya, Tetsuro; Hara, Hirokazu

    2016-09-15

    The number of potential applications of non-thermal atmospheric pressure plasma (NTAPP) discharges in medicine, particularly in cancer therapy, has increased in recent years. NTAPP has been shown to affect cells not only by direct irradiation, but also by an indirect treatment with previously prepared plasma-activated medium (PAM). Histone deacetylase (HDAC) inhibitors have the potential to enhance susceptibility to anticancer drugs and radiation. The aim of the present study was to demonstrate the advantage of the combined application of PAM and HDAC inhibitors on A549 cancer cell survival and elucidate the underlying mechanisms. Cell death with DNA breaks in the nucleus was greater using combined regimens of PAM and HDAC inhibitors such as trichostatin A (TSA) and valproic acid (VPA) than a single PAM treatment and was accompanied by the activation of poly (ADP-ribose) polymerase-1 (PARP-1), depletion of ATP, and elevations in intracellular calcium levels. Moreover, the expression of Rad 51, a DNA repair factor in homologous recombination pathways, was significantly suppressed by the treatment with HDAC inhibitors. These results demonstrate that HDAC inhibitors may synergistically induce the sensitivity of cancer cells to PAM components. PMID:27470189

  7. Natural Killer Cell-Based Therapies Targeting Cancer: Possible Strategies to Gain and Sustain Anti-Tumor Activity

    PubMed Central

    Dahlberg, Carin I. M.; Sarhan, Dhifaf; Chrobok, Michael; Duru, Adil D.; Alici, Evren

    2015-01-01

    Natural killer (NK) cells were discovered 40 years ago, by their ability to recognize and kill tumor cells without the requirement of prior antigen exposure. Since then, NK cells have been seen as promising agents for cell-based cancer therapies. However, NK cells represent only a minor fraction of the human lymphocyte population. Their skewed phenotype and impaired functionality during cancer progression necessitates the development of clinical protocols to activate and expand to high numbers ex vivo to be able to infuse sufficient numbers of functional NK cells to the cancer patients. Initial NK cell-based clinical trials suggested that NK cell-infusion is safe and feasible with almost no NK cell-related toxicity, including graft-versus-host disease. Complete remission and increased disease-free survival is shown in a small number of patients with hematological malignances. Furthermore, successful adoptive NK cell-based therapies from haploidentical donors have been demonstrated. Disappointingly, only limited anti-tumor effects have been demonstrated following NK cell infusion in patients with solid tumors. While NK cells have great potential in targeting tumor cells, the efficiency of NK cell functions in the tumor microenvironment is yet unclear. The failure of immune surveillance may in part be due to sustained immunological pressure on tumor cells resulting in the development of tumor escape variants that are invisible to the immune system. Alternatively, this could be due to the complex network of immune-suppressive compartments in the tumor microenvironment, including myeloid-derived suppressor cells, tumor-associated macrophages, and regulatory T cells. Although the negative effect of the tumor microenvironment on NK cells can be transiently reverted by ex vivo expansion and long-term activation, the aforementioned NK cell/tumor microenvironment interactions upon reinfusion are not fully elucidated. Within this context, genetic modification of NK cells

  8. Natural Killer Cell-Based Therapies Targeting Cancer: Possible Strategies to Gain and Sustain Anti-Tumor Activity.

    PubMed

    Dahlberg, Carin I M; Sarhan, Dhifaf; Chrobok, Michael; Duru, Adil D; Alici, Evren

    2015-01-01

    Natural killer (NK) cells were discovered 40 years ago, by their ability to recognize and kill tumor cells without the requirement of prior antigen exposure. Since then, NK cells have been seen as promising agents for cell-based cancer therapies. However, NK cells represent only a minor fraction of the human lymphocyte population. Their skewed phenotype and impaired functionality during cancer progression necessitates the development of clinical protocols to activate and expand to high numbers ex vivo to be able to infuse sufficient numbers of functional NK cells to the cancer patients. Initial NK cell-based clinical trials suggested that NK cell-infusion is safe and feasible with almost no NK cell-related toxicity, including graft-versus-host disease. Complete remission and increased disease-free survival is shown in a small number of patients with hematological malignances. Furthermore, successful adoptive NK cell-based therapies from haploidentical donors have been demonstrated. Disappointingly, only limited anti-tumor effects have been demonstrated following NK cell infusion in patients with solid tumors. While NK cells have great potential in targeting tumor cells, the efficiency of NK cell functions in the tumor microenvironment is yet unclear. The failure of immune surveillance may in part be due to sustained immunological pressure on tumor cells resulting in the development of tumor escape variants that are invisible to the immune system. Alternatively, this could be due to the complex network of immune-suppressive compartments in the tumor microenvironment, including myeloid-derived suppressor cells, tumor-associated macrophages, and regulatory T cells. Although the negative effect of the tumor microenvironment on NK cells can be transiently reverted by ex vivo expansion and long-term activation, the aforementioned NK cell/tumor microenvironment interactions upon reinfusion are not fully elucidated. Within this context, genetic modification of NK cells

  9. Promotion effect of manganese oxide on the electrocatalytic activity of Pt/C for methanol oxidation in acid medium

    NASA Astrophysics Data System (ADS)

    Abdel Hameed, R. M.; Fetohi, Amani E.; Amin, R. S.; El-Khatib, K. M.

    2015-12-01

    The modification of Pt/C by incorporating metal oxides for electrocatalytic oxidation of methanol has gained major attention because of the efficiency loss during the course of long-time operation. This work describes the preparation of Pt-MnO2/C electrocatalysts through a chemical route using ethylene glycol or a mixture of ethylene glycol and sodium borohydride as a reducing agent. The crystallite structure and particle size of synthesized electrocatalysts are determined using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The addition of MnO2 improves the dispersion of Pt nanoparticles. The electrocatalytic activity of Pt-MnO2/C towards methanol oxidation in H2SO4 solution is investigated using cyclic voltammetry and electrochemical impedance spectroscopy. The onset potential value of methanol oxidation peak is negatively shifted by 169 mV when MnO2 is introduced to Pt/C. Moreover, the charge transfer resistance value at Pt-MnO2/C is about 10 times as low as that at Pt/C. Chronoamperometry and chronopotentiometry show that CO tolerance is greatly improved at Pt-MnO2/C. The increased electrocatalytic activity and enhanced ability to clean platinum surface elect manganese oxide as a suitable promoter for the anode performance in direct methanol fuel cells (DMFCs).

  10. When your pain signifies my gain: neural activity while evaluating outcomes based on another person’s pain

    PubMed Central

    Cui, Fang; Zhu, Xiangru; Gu, Ruolei; Luo, Yue-jia

    2016-01-01

    The overlap between pain and reward processing pathways leds researchers to hypothesize that there are interactions between them in the human brain. Two hypotheses have been proposed. The “competition hypothesis” posits that reward can reduce pain-related neural activity and vice versa. The “salience hypothesis” suggests that the motivational salience of pain and reward can be mutually reinforced. However, no study has tested these two hypotheses from temporal perspective as we know. In the present study, pictures depicted other people in painful or non-painful situations were used to indicate the valence of outcomes in a gambling task. The event-related potential results revealed an interaction between another person’s pain and outcome valence in multiple time stages. Specifically, the amplitudes of the N1 and P3 were enhanced in the win condition compared with the loss condition when the outcome was indicated by painful picture. This interactions between pain and reward support the salience hypothesis but not the competition hypothesis. The present results provide evidence from human subjects that support the salience hypothesis, which claims that observing other people’s pain can enhance the salience of reward. PMID:27193060

  11. Inhibition of PRC2 activity by a gain-of-function H3 mutation found in pediatric glioblastoma.

    PubMed

    Lewis, Peter W; Müller, Manuel M; Koletsky, Matthew S; Cordero, Francisco; Lin, Shu; Banaszynski, Laura A; Garcia, Benjamin A; Muir, Tom W; Becher, Oren J; Allis, C David

    2013-05-17

    Sequencing of pediatric gliomas has identified missense mutations Lys27Met (K27M) and Gly34Arg/Val (G34R/V) in genes encoding histone H3.3 (H3F3A) and H3.1 (HIST3H1B). We report that human diffuse intrinsic pontine gliomas (DIPGs) containing the K27M mutation display significantly lower overall amounts of H3 with trimethylated lysine 27 (H3K27me3) and that histone H3K27M transgenes are sufficient to reduce the amounts of H3K27me3 in vitro and in vivo. We find that H3K27M inhibits the enzymatic activity of the Polycomb repressive complex 2 through interaction with the EZH2 subunit. In addition, transgenes containing lysine-to-methionine substitutions at other known methylated lysines (H3K9 and H3K36) are sufficient to cause specific reduction in methylation through inhibition of SET-domain enzymes. We propose that K-to-M substitutions may represent a mechanism to alter epigenetic states in a variety of pathologies. PMID:23539183

  12. Nicotine Replacement: Effects on Postcessation Weight Gain.

    ERIC Educational Resources Information Center

    Gross, Janet; And Others

    1989-01-01

    Examined nicotine replacement effects on postcessation weight gain in smoking cessation volunteers. Randomly assigned abstinent subjects to active nicotine or placebo gum conditions for 10 weeks. Analyses revealed strong evidence for gum effect on weight gain, with active gum users gaining mean total of 3.8 pounds compared with 7.8 pounds for…

  13. Somatic proembryo production from excised, wounded zygotic carrot embryos on hormone-free medium: evaluation of the effects of pH, ethylene and activated charcoal

    NASA Technical Reports Server (NTRS)

    Smith, D. L.; Krikorian, A. D.

    1990-01-01

    Wounded zygotic embryos of cultivated carrot produce somatic proembryos on hormone-free nutrient medium containing 1 mM NH4+ as the sole nitrogen source. Continued maintenance of proembryos on this medium leads to a "pure" culture of preglobular stage proembryos (PGSPs). Ethylene had no effect on this process. Also, somatic embryo production was not affected by growing cultures on activated charcoal-impregnated filter papers. However, somatic proembyros initiated on activated charcoal papers were not maintainable as PGSPs and developed into later embryo stages. Normally, medium pH dropped from 5.7 to 4 during each subculture period, but when using activated charcoal papers the pH endpoint was around 6 - 7 due to a leachable substance(s) within the filter papers. When powdered, activated charcoal was used in the medium as an adsorbent of products potentially released after wounding, pH dropped at the normal rate and to the expected levels; proembryos did not mature into later embryo stages and were maintainable exclusively as PGSPs. Low pH (approximately 4) is detrimental to proembyro production, but is essential to maintaining PGSPs on hormone-free nutrient medium, whereas a sustained pH > or = 5.7 allows continued development of PGSPs into later embryo stages.

  14. An infrared jet in Centaurus A (NGC 5128): Evidence for interaction between the active nucleus and the interstellar medium

    NASA Technical Reports Server (NTRS)

    Joy, Marshall; Harvey, P. M.; Tollestrup, E. V.; Mcgregor, P. J.; Hyland, A. R.

    1990-01-01

    In the present study, higher resolution near infrared images of the visually-obscured central region of Centaurus A were obtained in order to investigate the effects of the active nucleus on the surrounding galaxy. Researchers present J(1.25 microns), H(1.65 microns), and K(2.2 microns) images of the central 40 seconds of the galaxy, taken with the Univ. of Texas InSb array camera on the Anglo Australian 3.9 meter telescope. These images reveal a jet extending approx. 10 arcseconds to the northeast of the nucleus at the same position angle as the x ray and radio jets. The infrared jet is most prominent at the shortest wavelength (1.25 microns), where its brightness surpasses that of the nucleus. The blue appearance of the infrared jet is remarkable considering the heavy obscuration that is evident at visual wavelengths. The amount of reddening in the vicinity of the jet is determined from the measured colors of the stellar core of the galaxy, and this value is used to generate an extinction-corrected energy distribution. In contrast to previously studied optical and infrared jets in active nuclei, the short-wavelength prominence of the Cen A jet indicates that it cannot be attributed to synchrotron emission from a beam of relativistic electrons. The remaining viable mechanisms involve an interaction between the interstellar medium and the active nucleus: the infrared radiation from the jet may be due to emission from interstellar gas that has been entrained and heated by the flow of relativistic particles from the nucleus; alternatively, luminous blue stars may have been created by compression of interstellar material by the relativistic plasma. To investigate these proposed mechanisms, near-infrared spectroscopic studies of Cen A are in progress to look for collisionally excited molecular hydrogen emission lines and recombination lines from ionized gas.

  15. Investigation of selective induction of breast cancer cells to death with treatment of plasma-activated medium

    NASA Astrophysics Data System (ADS)

    Hashizume, Hiroshi; Tanaka, Hiromasa; Nakamura, Kae; Kano, Hiroyuki; Ishikawa, Kenji; Kikkawa, Fumitaka; Mizuno, Masaaki; Hori, Masaru

    2015-09-01

    The applications of plasma in medicine have much attention. We previously showed that plasma-activated medium (PAM) induced glioblastoma cells to apoptosis. However, it has not been elucidated the selectivity of PAM in detail. In this study, we investigated the selective effect of PAM on the death of human breast normal and cancer cells, MCF10A and MCF7, respectively, and observed the selective death with fluorescent microscopy. For the investigation of cell viability with PAM treatment, we prepared various PAMs according to the strengths, and treated each of cells with PAMs. Week PAM treatment only decreased the viability of MCF7 cells, while strong PAM treatment significantly affected both viabilities of MCF7 and MCF10A cells. For the fluorescent observation, we prepared the mixture of MCF7 and fluorescent-probed MCF10A cells, and seeded them. After the treatment of PAMs, the images showed that only MCF7 cells damaged in the mixture with week PAM treatment. These results suggested that a specific range existed with the selective effect in the strength of PAM. This work was partly supported by a Grant-in-Aid for Scientific Research on Innovative Areas ``Plasma Medical Innovation'' Grant No. 24108002 and 24108008 from the Ministry of Education, Culture, Sports, Science and Technology of Japan.

  16. Radioactively contaminated electric arc furnace dust as an addition to the immobilization mortar in low- and medium-activity repositories.

    PubMed

    Castellote, Marta; Menéndez, Esperanza; Andrade, Carmen; Zuloaga, Pablo; Navarro, Mariano; Ordóñez, Manuel

    2004-05-15

    Electric arc furnace dust (EAFD), generated by the steel-making industry, is in itself an intrinsic hazardous waste; however, the case may also be that scrap used in the process is accidentally contaminated by radioactive elements such as cesium. In this case the resulting EAFD is to be handled as radioactive waste, being duly confined in low- and medium-activity repositories (LMAR). What this paper studies is the reliability of using this radioactive EAFD as an addition in the immobilization mortar of the containers of the LMAR, that is, from the point of view of the durability. Different mixes of mortar containing different percentages of EAFD have been subjected to flexural and compressive strength, initial and final setting time, XRD study, total porosity and pore size distribution, determination of the chloride diffusion coefficient, dimensional stability tests, hydration heat, workability of the fresh mix, and leaching behavior. What is deduced from the results is that for the conditions used in this research, (cement + sand) can be replaced by EAFD upto a ratio [EAFD/(cement + EAFD)] of 46% in the immobilization mortar of LMAR, apparently without any loss in the long-term durability properties of the mortar.

  17. Plasma-activated medium suppresses choroidal neovascularization in mice: a new therapeutic concept for age-related macular degeneration.

    PubMed

    Ye, Fuxiang; Kaneko, Hiroki; Nagasaka, Yosuke; Ijima, Ryo; Nakamura, Kae; Nagaya, Masatoshi; Takayama, Kei; Kajiyama, Hiroaki; Senga, Takeshi; Tanaka, Hiromasa; Mizuno, Masaaki; Kikkawa, Fumitaka; Hori, Masaru; Terasaki, Hiroko

    2015-01-01

    Choroidal neovascularization (CNV) is the main pathogenesis of age-related macular degeneration (AMD), which leads to severe vision loss in many aged patients in most advanced country. CNV compromises vision via hemorrhage and retinal detachment on account of pathological neovascularization penetrating the retina. Plasma medicine represents the medical application of ionized gas "plasma" that is typically studied in the field of physical science. Here we examined the therapeutic ability of plasma-activated medium (PAM) to suppress CNV. The effect of PAM on vascularization was assessed on the basis of human retinal endothelial cell (HREC) tube formation. In mice, laser photocoagulation was performed to induce CNV (laser-CNV), followed by intravitreal injection of PAM. N-Acetylcysteine was used to examine the role of reactive oxygen species in PAM-induced CNV suppression. Fundus imaging, retinal histology examination, and electroretinography (ERG) were also performed to evaluate PAM-induced retinal toxicity. Interestingly, HREC tube formation and laser-CNV were both reduced by treatment with PAM. N-acetylcysteine only partly neutralized the PAM-induced reduction in laser-CNV. In addition, PAM injection had no effect on regular retinal vessels, nor did it show retinal toxicity in vivo. Our findings indicate the potential of PAM as a novel therapeutic agent for suppressing CNV.

  18. Normal hematopoiesis and lack of β-catenin activation in osteoblasts of patients and mice harboring Lrp5 gain-of-function mutations☆, ☆☆

    PubMed Central

    Galán-Díez, Marta; Isa, Adiba; Ponzetti, Marco; Nielsen, Morten Frost; Kassem, Moustapha; Kousteni, Stavroula

    2016-01-01

    Osteoblasts are emerging regulators of myeloid malignancies since genetic alterations in them, such as constitutive activation of β-catenin, instigate their appearance. The LDL receptor-related protein 5 (LRP5), initially proposed to be a co-receptor for Wnt proteins, in fact favors bone formation by suppressing gut-serotonin synthesis. This function of Lrp5 occurring in the gut is independent of β-catenin activation in osteoblasts. However, it is unknown whether Lrp5 can act directly in osteoblast to influence other functions that require β-catenin signaling, particularly, the deregulation of hematopoiesis and leukemogenic properties of β-catenin activation in osteoblasts, that lead to development of acute myeloid leukemia (AML). Using mice with gain-of-function (GOF) Lrp5 alleles (Lrp5A214V) that recapitulate the human high bone mass (HBM) phenotype, as well as patients with the T253I HBM Lrp5 mutation, we show here that Lrp5 GOF mutations in both humans and mice do not activate β-catenin signaling in osteoblasts. Consistent with a lack of β-catenin activation in their osteoblasts, Lrp5A214V mice have normal trilinear hematopoiesis. In contrast to leukemic mice with constitutive activation of β-catenin in osteoblasts (Ctnnb1CAosb), accumulation of early myeloid progenitors, a characteristic of AML, myeloid-blasts in blood, and segmented neutrophils or dysplastic megakaryocytes in the bone marrow, are not observed in Lrp5A214V mice. Likewise, peripheral blood count analysis in HBM patients showed normal hematopoiesis, normal percentage of myeloid cells, and lack of anemia. We conclude that Lrp5 GOF mutations do not activate β-catenin signaling in osteoblasts. As a result, myeloid lineage differentiation is normal in HBM patients and mice. This article is part of a Special Issue entitled: Tumor Microenvironment Regulation of Cancer Cell Survival, Metastasis, Inflammation, and Immune Surveillance edited by Peter Ruvolo and Gregg L. Semenza. PMID:26681532

  19. Pore structure effects on Ca-based sorbent sulfation capacity at medium temperatures: activated carbon as sorbent/catalyst support.

    PubMed

    Tseng, Hui-Hsin; Wey, Ming-Yen; Lin, Chiou-Liang; Chang, Yu-Chen

    2002-11-01

    The reaction between three different Ca-based sorbents and SO2 were studied in a medium temperature range (473-773 K). The largest SO2 capture was found with Ca(OH)2 at 773 K, 126.31 mg SO2 x g Ca(OH)2(-1), and the influence of SO2 concentration on the sorbent utilization was observed. Investigations of the internal porous structure of Ca-based sorbents showed that the initial reaction rate was controlled by the surface area, and once the sulfated products were produced, pore structure dominated. To increase the surface area of Ca-based sorbents available to interact with and retain SO2, one kind of CaO/ activated carbon (AC) sorbent/catalyst was prepared to study the effect of AC on the dispersion of Ca-based materials. The results indicated that the Ca-based material dispersed on high-surface-area AC had more capacities for SO2 than unsupported Ca-based sorbents. The initial reaction rates of the reaction between SO2 and Ca-based sorbents and the prepared CaO/AC sorbents/catalysts were measured. Results showed that the reaction rate apparently increased with the presence of AC. It was concluded that CaO/AC was the active material in the desulfurization reaction. AC acting as the support can play a role to supply O2 to increase the affinity to SO2. Moreover, when AC is acting as a support, the surface oxygen functional group formed on the surface of AC can serve as a new site for SO2 adsorption.

  20. How common is "parking" among Social Security Disability Insurance beneficiaries? Evidence from the 1999 change in the earnings level of substantial gainful activity.

    PubMed

    Schimmel, Jody; Stapleton, David C; Song, Jae G

    2011-01-01

    Fewer Social Security Disability Insurance (DI) beneficiaries have their earnings suspended or terminated because of work than those who are actually working, partly because beneficiaries "park" earnings at a level below substantial gainful activity (SGA) to retain benefits. We assess the extent of parking by exploiting the 1999 change in the SGA earnings level from $500 to $700 monthly for nonblind beneficiaries using a difference-indifference analysis that compares two annual cohorts of beneficiaries who completed their trial work period, one that was affected by the SGA change and one that was not. Our impact estimates, along with results from other sources, suggest that from 0.2 to 0.4 percent of all DI beneficiaries were parked below the SGA level in the typical month from 2002 through 2006. The SGA change did not yield any difference in mean earnings, although it did result in a small reduction in months spent off of the rolls because of work.

  1. The Study of Electromagnetic Wave Propogation in Photonic Crystals Via Planewave Based Transfer (Scattering) Matrix Method with Active Gain Material Applications

    SciTech Connect

    LI, Ming

    2007-01-01

    In this dissertation, a set of numerical simulation tools are developed under previous work to efficiently and accurately study one-dimensional (1D), two-dimensional(2D), 2D slab and three-dimensional (3D) photonic crystal structures and their defects effects by means of spectrum (transmission, reflection, absorption), band structure (dispersion relation), and electric and/or magnetic fields distribution (mode profiles). Furthermore, the lasing property and spontaneous emission behaviors are studied when active gain materials are presented in the photonic crystal structures. Various physical properties such as resonant cavity quality factor, waveguide loss, propagation group velocity of electromagnetic wave and light-current curve (for lasing devices) can be obtained from the developed software package.

  2. Random lasing with spatially nonuniform gain

    NASA Astrophysics Data System (ADS)

    Fan, Ting; Lü, Jiantao

    2016-07-01

    Spatial and spectral properties of random lasing with spatially nonuniform gain were investigated in two-dimensional (2D) disordered medium. The pumping light was described by an individual electric field and coupled into the rate equations by using the polarization equation. The spatially nonuniform gain comes from the multiple scattering of this pumping light. Numerical simulation of the random system with uniform and nonuniform gain were performed both in weak and strong scattering regime. In weak scattering sample, all the lasing modes correspond to those of the passive system whether the nonuniform gain is considered. However, in strong scattering regime, new lasing modes appear with nonuniform gain as the localization area changes. Our results show that it is more accurate to describe the random lasing behavior with introducing the nonuniform gain origins from the multiple light scattering.

  3. Global expression profiling reveals gain-of-function onco-genic activity of a mutated thyroid hormone receptor in thyroid carcinogenesis

    PubMed Central

    Lu, Changxue; Mishra, Alok; Zhu, Yuelin J; Meltzer, Paul; Cheng, Sheue-yann

    2011-01-01

    Thyroid hormone receptors (TRs) are critical in regulating gene expression in normal physiological processes. Decreased expression and/or somatic mutations of TRs have been shown to be associated several types of human cancers including liver, breast, lung, and thyroid. To understand the molecular mechanisms by which mutated TRs promote carcinogenesis, an animal model of follicular thyroid carcinoma (FTC) (Thrbpv/pv mice) was used in the present study. The Thrbpv/pv mouse harbors a knockin dominant negative PV mutation, identified in a patient with resistance to thyroid hormone. To understand whether oncogenic actions of PV involve not only the loss of normal TR functions but also gain-of-function activities, we compared the gene expression profiles of thyroid lesions in Thrbpv/pv mice and Thra1-/- Thrb-/- mice that also spontaneously develop FTC, but with less severe malignancy. Analysis of the cDNA microarray data derived from microdissected thyroid tumor cells of these two mice showed contrasting global gene expression profiles. With stringent selection using 2.5-fold change (p<0.01) in cDNA microarray analysis, 241 genes with altered gene expression were identified. Nearly half of the genes (n=103: 42.7% of total) with altered gene expression in thyroid tumor cells of Thrbpv/pv mice were associated with tumorigenesis and metastasis; some of these genes function as oncogenes in human thyroid cancers. The remaining genes were found to function in transcriptional regulation, RNA processing, cell proliferation, apoptosis, angiogenesis, and cytoskeleton modification. These results indicate that the more aggressive thyroid tumor progression in Thrbpv/pv mice was not due simply to the loss of tumor suppressor functions of TR via mutation but also, importantly, to gain-of-function in the oncogenic activities of PV to drive thyroid carcinogenesis. Thus, the present study identifies a novel mechanism by which a mutated TRβ evolves with an oncogenic advantage to promote

  4. Use of a photonic crystal for optical amplifier gain control

    DOEpatents

    Lin, Shawn-Yu; Fleming, James G.; El-Kady, Ihab

    2006-07-18

    An optical amplifier having a uniform gain profile uses a photonic crystal to tune the density-of-states of a gain medium so as to modify the light emission rate between atomic states. The density-of-states of the gain medium is tuned by selecting the size, shape, dielectric constant, and spacing of a plurality of microcavity defects in the photonic crystal. The optical amplifier is particularly useful for the regeneration of DWDM signals in long optical fibers.

  5. Weight gain - unintentional

    MedlinePlus

    ... as much as 25 to 30 pounds. This weight gain is not simply due to eating more. ... or a dietitian about how to make a healthy eating plan and set ... be causing the weight gain without talking with your provider.

  6. The study of electromagnetic wave propagation in photonic crystals via planewave based transfer (scattering) matrix method with active gain material applications

    NASA Astrophysics Data System (ADS)

    Li, Ming

    In this dissertation, a set of numerical simulation tools are developed under previous work to efficiently and accurately study one-dimensional (1D), two-dimensional (2D), 2D slab and three-dimensional (3D) photonic crystal structures and their defects effects by means of spectrum (transmission, reflection, absorption), band structure (dispersion relation), and electric and/or magnetic fields distribution (mode profiles). Further more, the lasing property and spontaneous emission behaviors are studied when active gain materials are presented in the photonic crystal structures. First, the planewave based transfer (scattering) matrix method (TMM) is described in every detail along with a brief review of photonic crystal history (Chapter 1 and 2). As a frequency domain method, TMM has the following major advantages over other numerical methods: (1) the planewave basis makes Maxwell's Equations a linear algebra problem and there are mature numerical package to solve linear algebra problem such as Lapack and Scalapack (for parallel computation). (2) Transfer (scattering) matrix method make 3D problem into 2D slices and link all slices together via the scattering matrix (S matrix) which reduces computation time and memory usage dramatically and makes 3D real photonic crystal devices design possible; and this also makes the simulated domain no length limitation along the propagation direction (ideal for waveguide simulation). (3) It is a frequency domain method and calculation results are all for steady state, without the influences of finite time span convolution effects and/or transient effects. (4) TMM can treat dispersive material (such as metal at visible light) naturally without introducing any additional computation; and meanwhile TMM can also deal with anisotropic material and magnetic material (such as perfectly matched layer) naturally from its algorithms. (5) Extension of TMM to deal with active gain material can be done through an iteration procedure with gain

  7. Effect of temperature and water activity on gene expression and aflatoxin biosynthesis in Aspergillus flavus on almond medium.

    PubMed

    Gallo, Antonia; Solfrizzo, Michele; Epifani, Filomena; Panzarini, Giuseppe; Perrone, Giancarlo

    2016-01-18

    Almonds are among the commodities at risk of aflatoxin contamination by Aspergillus flavus. Temperature and water activity are the two key determinants in pre and post-harvest environments influencing both the rate of fungal spoilage and aflatoxin production. Varying the combination of these parameters can completely inhibit or fully activate the biosynthesis of aflatoxin, so it is fundamental to know which combinations can control or be conducive to aflatoxin contamination. Little information is available about the influence of these parameters on aflatoxin production on almonds. The objective of this study was to determine the influence of different combinations of temperature (20 °C, 28 °C, and 37 °C) and water activity (0.90, 0.93, 0.96, 0.99 aw) on growth, aflatoxin B1 (AFB1) production and expression of the two regulatory genes, aflR and aflS, and two structural genes, aflD and aflO, of the aflatoxin biosynthetic cluster in A. flavus grown on an almond medium solidified with agar. Maximum accumulation of fungal biomass and AFB1 production was obtained at 28 °C and 0.96 aw; no fungal growth and AFB1 production were observed at 20 °C at the driest tested conditions (0.90 and 0.93 aw). At 20° and 37 °C AFB1 production was 70-90% lower or completely suppressed, depending on aw. Reverse transcriptase quantitative PCR showed that the two regulatory genes (aflR and aflS) were highly expressed at maximum (28 °C) and minimum (20 °C and 37 °C) AFB1 production. Conversely the two structural genes (aflD and aflO) were highly expressed only at maximum AFB1 production (28 °C and 0.96-0.99 aw). It seems that temperature acts as a key factor influencing aflatoxin production which is strictly correlated to the induction of expression of structural biosynthesis genes (aflD and aflO), but not to that of aflatoxin regulatory genes (aflR and aflS), whose functional products are most likely subordinated to other regulatory processes acting at post-translational level

  8. Effect of temperature and water activity on gene expression and aflatoxin biosynthesis in Aspergillus flavus on almond medium.

    PubMed

    Gallo, Antonia; Solfrizzo, Michele; Epifani, Filomena; Panzarini, Giuseppe; Perrone, Giancarlo

    2016-01-18

    Almonds are among the commodities at risk of aflatoxin contamination by Aspergillus flavus. Temperature and water activity are the two key determinants in pre and post-harvest environments influencing both the rate of fungal spoilage and aflatoxin production. Varying the combination of these parameters can completely inhibit or fully activate the biosynthesis of aflatoxin, so it is fundamental to know which combinations can control or be conducive to aflatoxin contamination. Little information is available about the influence of these parameters on aflatoxin production on almonds. The objective of this study was to determine the influence of different combinations of temperature (20 °C, 28 °C, and 37 °C) and water activity (0.90, 0.93, 0.96, 0.99 aw) on growth, aflatoxin B1 (AFB1) production and expression of the two regulatory genes, aflR and aflS, and two structural genes, aflD and aflO, of the aflatoxin biosynthetic cluster in A. flavus grown on an almond medium solidified with agar. Maximum accumulation of fungal biomass and AFB1 production was obtained at 28 °C and 0.96 aw; no fungal growth and AFB1 production were observed at 20 °C at the driest tested conditions (0.90 and 0.93 aw). At 20° and 37 °C AFB1 production was 70-90% lower or completely suppressed, depending on aw. Reverse transcriptase quantitative PCR showed that the two regulatory genes (aflR and aflS) were highly expressed at maximum (28 °C) and minimum (20 °C and 37 °C) AFB1 production. Conversely the two structural genes (aflD and aflO) were highly expressed only at maximum AFB1 production (28 °C and 0.96-0.99 aw). It seems that temperature acts as a key factor influencing aflatoxin production which is strictly correlated to the induction of expression of structural biosynthesis genes (aflD and aflO), but not to that of aflatoxin regulatory genes (aflR and aflS), whose functional products are most likely subordinated to other regulatory processes acting at post-translational level

  9. DRIVING OUTFLOWS WITH RELATIVISTIC JETS AND THE DEPENDENCE OF ACTIVE GALACTIC NUCLEUS FEEDBACK EFFICIENCY ON INTERSTELLAR MEDIUM INHOMOGENEITY

    SciTech Connect

    Wagner, A. Y.; Umemura, M.; Bicknell, G. V.

    2012-10-01

    We examine the detailed physics of the feedback mechanism by relativistic active galactic nucleus (AGN) jets interacting with a two-phase fractal interstellar medium (ISM) in the kpc-scale core of galaxies using 29 three-dimensional grid-based hydrodynamical simulations. The feedback efficiency, as measured by the amount of cloud dispersal generated by the jet-ISM interactions, is sensitive to the maximum size of clouds in the fractal cloud distribution but not to their volume filling factor. Feedback ceases to be efficient for Eddington ratios P{sub jet}/L{sub edd} {approx}< 10{sup -4}, although systems with large cloud complexes {approx}> 50 pc require jets of Eddington ratio in excess of 10{sup -2} to disperse the clouds appreciably. Based on measurements of the bubble expansion rates in our simulations, we argue that sub-grid AGN prescriptions resulting in negative feedback in cosmological simulations without a multi-phase treatment of the ISM are good approximations if the volume filling factor of warm-phase material is less than 0.1 and the cloud complexes are smaller than {approx}25 pc. We find that the acceleration of the dense embedded clouds is provided by the ram pressure of the high-velocity flow through the porous channels of the warm phase, flow that has fully entrained the shocked hot-phase gas it has swept up, and is additionally mass loaded by ablated cloud material. This mechanism transfers 10% to 40% of the jet energy to the cold and warm gas, accelerating it within a few 10 to 100 Myr to velocities that match those observed in a range of high- and low-redshift radio galaxies hosting powerful radio jets.

  10. Gain-of-Function Mutations in the Toll-Like Receptor Pathway: TPL2-Mediated ERK1/ERK2 MAPK Activation, a Path to Tumorigenesis in Lymphoid Neoplasms?

    PubMed Central

    Rousseau, Simon; Martel, Guy

    2016-01-01

    Lymphoid neoplasms form a family of cancers affecting B-cells, T-cells, and NK cells. The Toll-Like Receptor (TLR) signaling adapter molecule MYD88 is the most frequently mutated gene in these neoplasms. This signaling adaptor relays signals from TLRs to downstream effector pathways such as the Nuclear Factor kappa B (NFκB) and Mitogen Activated Protein Kinase (MAPK) pathways to regulate innate immune responses. Gain-of-function mutations such as MYD88[L265P] activate downstream signaling pathways in absence of cognate ligands for TLRs, resulting in increased cellular proliferation and survival. This article reports an analysis of non-synonymous somatic mutations found in the TLR signaling network in lymphoid neoplasms. In accordance with previous reports, mutations map to MYD88 pro-inflammatory signaling and not TRIF-mediated Type I IFN production. Interestingly, the analysis of somatic mutations found downstream of the core TLR-signaling network uncovered a strong association with the ERK1/2 MAPK cascade. In support of this analysis, heterologous expression of MYD88[L265P] in HEK293 cells led to ERK1/2 MAPK phosphorylation in addition to NFκB activation. Moreover, this activation is dependent on the protein kinase Tumor Promoting Locus 2 (TPL2), activated downstream of the IKK complex. Activation of ERK1/2 would then lead to activation, amongst others, of MYC and hnRNPA1, two proteins previously shown to contribute to tumor formation in lymphoid neoplasms. Taken together, this analysis suggests that TLR-mediated ERK1/2 activation via TPL2 may be a novel path to tumorigenesis. Therefore, the hypothesis proposed is that inhibition of ERK1/2 MAPK activation would prevent tumor growth downstream of MYD88[L265]. It will be interesting to test whether pharmacological inhibitors of this pathway show efficacy in primary tumor cells derived from hematologic malignancies such as Waldenstrom's Macroglobulinemia, where the majority of the cells carry the MYD88[L265P

  11. Effects of preincubation of eggs and activation medium on the percentage of eyed embryos in ide (Leuciscus idus), an externally fertilizing fish.

    PubMed

    Siddique, Mohammad Abdul Momin; Linhart, Otomar; Krejszeff, Sławomir; Żarski, Daniel; Król, Jarosław; Butts, Ian Anthony Ernest

    2016-03-15

    Standardization of fertilization protocols is crucial for improving reproductive techniques for externally fertilizing fish in captive breeding. Therefore, the objectives of this study were to determine the effects of preincubation of eggs and activation medium on the percentage of eyed embryos for ide (Leuciscus idus). Pooled eggs from five females were preincubated in three different activating media for 0, 30, 60, 90, and 120 seconds and then fertilized by pooled sperm from five males. At the eyed-egg stage, the percentage of viable embryos was later calculated. Results showed that preincubation time was significant for the freshwater activation medium (P < 0.001), such that the percentage of eyed embryos declined across the preincubation time gradient. Additionally, there was an effect on the percentage of eyed embryos when eggs were incubated with Woynarovich solution (P < 0.001), such that a decline was detected at 90 seconds, whereas no effect was detected for the saline water medium. Activating medium had a significant effect on the percentage of eyed embryos for each preincubation time (P < 0.05). More precisely, freshwater produced the lowest percentage of eyed embryos at all preincubation times (ranged from 1.9% at 120 seconds to 43.6% at 0 seconds), whereas saline water and Woynarovich solution produced the highest percentage of eyed embryos at 0 seconds and 30 seconds before incubation. Woynarovich solution produced the highest percentage of eyed embryos at 60 seconds (65.26%), whereas saline water produced the highest percentage at 90 seconds (68.37%). No difference was detected between saline water and Woynarovich solution at 120 seconds. Examination of sperm traits showed no impact of activating medium on computer assisted sperm analysis parameters. Together, these results suggest that saline water or Woynarovich solution improve fertilization rate in ide during IVF; thus, these media are useful for standardizing fertilization protocols and

  12. Giant Raman gain in silicon nanocrystals

    PubMed Central

    Sirleto, Luigi; Antonietta Ferrara, Maria; Nikitin, Timur; Novikov, Sergei; Khriachtchev, Leonid

    2012-01-01

    Nanostructured silicon has generated a lot of interest in the past decades as a key material for silicon-based photonics. The low absorption coefficient makes silicon nanocrystals attractive as an active medium in waveguide structures, and their third-order nonlinear optical properties are crucial for the development of next generation nonlinear photonic devices. Here we report the first observation of stimulated Raman scattering in silicon nanocrystals embedded in a silica matrix under non-resonant excitation at infrared wavelengths (~1.5 μm). Raman gain is directly measured as a function of the silicon content. A giant Raman gain from the silicon nanocrystals is obtained that is up to four orders of magnitude greater than in crystalline silicon. These results demonstrate the first Raman amplifier based on silicon nanocrystals in a silica matrix, thus opening new perspectives for the realization of more efficient Raman lasers with ultra-small sizes, which would increase the synergy between electronic and photonic devices. PMID:23187620

  13. Differentiation of purified astrocytes in a chemically defined medium

    SciTech Connect

    Morrison, R.S.; de Vellis, J.

    1981-01-01

    Homogeneous cultures of astrocytes and oligodendrocytes provide an excellent model system for studying the regulation of glial structure and function. Recently, a chemically defined (CD) medium was developed for purified cultures of astrocytes, thus eliminating the requirement for serum and providing a controlled system for the study of astroglial properties. Due to the widespread use of astrocyte cultures and the potential benefits to be gained from using a defined medium, astrocyte cultures raised in CD medium were analyzed for purity as well as morphological and biochemical properties. Purity was assessed using immunocytochemical staining for glial fibrillary acidic protein (GFAP) and fibronectin. Astrocytes raised in CD medium are 95% pure using the expression of GFAP as a criterion. Fewer than 1% of the cells in CD medium stained positive for fibronectin eliminating the possibility that CD medium is selective for meningeal or endothelial cells. Astrocytes raised in CD medium exhibit a striking degree of morphological differentiation as seen in scanning electron micrographs. They also exhibit a high degree of biochemical differentiation illustrated by increases in the specific activity of S-100 protein and the induction of glutamine synthetase by glucocorticoids. A defined medium that supports the proliferation of rat astrocytes and enhances numerous morphological and biochemical properties should greatly facilitate the study of factors controlling glial proliferation and differentiation.

  14. Acting to gain information

    NASA Technical Reports Server (NTRS)

    Rosenchein, Stanley J.; Burns, J. Brian; Chapman, David; Kaelbling, Leslie P.; Kahn, Philip; Nishihara, H. Keith; Turk, Matthew

    1993-01-01

    This report is concerned with agents that act to gain information. In previous work, we developed agent models combining qualitative modeling with real-time control. That work, however, focused primarily on actions that affect physical states of the environment. The current study extends that work by explicitly considering problems of active information-gathering and by exploring specialized aspects of information-gathering in computational perception, learning, and language. In our theoretical investigations, we analyzed agents into their perceptual and action components and identified these with elements of a state-machine model of control. The mathematical properties of each was developed in isolation and interactions were then studied. We considered the complexity dimension and the uncertainty dimension and related these to intelligent-agent design issues. We also explored active information gathering in visual processing. Working within the active vision paradigm, we developed a concept of 'minimal meaningful measurements' suitable for demand-driven vision. We then developed and tested an architecture for ongoing recognition and interpretation of visual information. In the area of information gathering through learning, we explored techniques for coping with combinatorial complexity. We also explored information gathering through explicit linguistic action by considering the nature of conversational rules, coordination, and situated communication behavior.

  15. Dissociation and regeneration kinetics of carbon dioxide in the active medium of sealed-off transverse RF-excited CO{sub 2} lasers

    SciTech Connect

    Vesnov, I G

    2010-06-23

    An improved mathematical model describing the dissociation and regenerations kinetics of carbon dioxide in the active medium of sealed-off transverse RF-excited CO{sub 2} lasers is presented. It is shown that the calculation of the active medium composition of such lasers requires the equations of the gas-mixture kinetics to take into account the diffuse flow of oxygen atoms on metal electrodes and on the surface of heterogeneous catalysts used to reduce the degree of the carbon dioxide dissociation. The rate constants of the heterogeneous recombination reaction CO + O {yields} CO{sub 2} on the surface of alumina ceramics and Al{sub 2}O{sub 3} are determined. (active media)

  16. Gain weighted eigenspace assignment

    NASA Technical Reports Server (NTRS)

    Davidson, John B.; Andrisani, Dominick, II

    1994-01-01

    This report presents the development of the gain weighted eigenspace assignment methodology. This provides a designer with a systematic methodology for trading off eigenvector placement versus gain magnitudes, while still maintaining desired closed-loop eigenvalue locations. This is accomplished by forming a cost function composed of a scalar measure of error between desired and achievable eigenvectors and a scalar measure of gain magnitude, determining analytical expressions for the gradients, and solving for the optimal solution by numerical iteration. For this development the scalar measure of gain magnitude is chosen to be a weighted sum of the squares of all the individual elements of the feedback gain matrix. An example is presented to demonstrate the method. In this example, solutions yielding achievable eigenvectors close to the desired eigenvectors are obtained with significant reductions in gain magnitude compared to a solution obtained using a previously developed eigenspace (eigenstructure) assignment method.

  17. Impact of substrates and cell immobilization on siderophore activity by Pseudomonads in a Fe and/or Cr, Hg, Pb containing-medium.

    PubMed

    Braud, Armelle; Jézéquel, Karine; Lebeau, Thierry

    2007-06-01

    To increase the amount of bioavailable metals in phytoextraction purposes, soil bioaugmentation with Pseudomonads, as siderophore producers with high metal complexation levels, could be relevant. Unfortunately, siderophore synthesis may be inhibited by soluble iron in soil and bacteria can suffer at the same time from the toxicity of some other metals, predation and oligotrophy. To overcome these drawbacks, we attempted to co-locate a carbon substrate and Pseudomonas aeruginosa or P. fluorescens in Ca-alginate beads. First, free-cell cultures showed that glycerol, fructose, mannitol and skim milk enhanced the siderophore activity which was the highest in the medium with neither Fe or TM (toxic metal) (Cr, Hg and Pb) and the lowest in the Fe-containing medium without TM. The negative effect of iron was partly offset when TM was added to the medium. In a second part, co-location of microorganisms and substrates was only feasible with skim milk. By comparison with free cells, siderophore activity by immobilized cells was higher in culture media containing Fe with or without TM (up to a ratio of 9), and varied in a narrow margin, according to the medium composition. PMID:17112663

  18. Coupling hydrologic and hydraulic modelling for reliable flood risk mitigation activities in the Upper-Medium Tiber River basin

    NASA Astrophysics Data System (ADS)

    Berni, N.; Brocca, L.; Giustarini, L.; Pandolfo, C.; Stelluti, M.; Melone, F.; Moramarco, T.

    2009-04-01

    In view of the recent and serious flood events occurred in latest years in Italy, the interest towards accurate methodology for the evaluation of flood prone areas is continually increasing. In particular, this issue is related to urbanization planning activities, civil protection actions (e.g. hydraulic risk warning systems), and the assessment of hydraulic engineering structures behaviour during severe hydrometeorological conditions. In Italy, following the publishing in the late 90's of many laws and regulations concerning hydraulic risk assessment matters, a widespread flooding areas mapping have been carried out (Italian Basin Authorities "PAI" plans). In case of limited availability of historical peak flow data, the flood prone areas estimation was based on the application of hydrologic and hydraulic modelling separately. Moreover, the recent directive 2007/60/EC on the assessment and management of flood risks requires from each member state: preliminary flood risk assessment (within December 2011), flood hazard maps and flood risk maps (within December 2013), flood risk management plans (within December 2015). In order to prevent and control flood events in medium-small river basins (e.g. Upper Tiber River basin, Central Italy), the use of hydrologic models coupled with hydraulic ones can be a valuable tool also for real time applications, such as flood risk mitigation and warning activities of the Italian National Warning System Network (composed by regional "Functional Centres" coordinated by the National Civil Protection Department). In this context, two significant flood events occurred in November 2005 and December 2008 in the Umbria Region territory were considered. In this area a hydrometeorological network, characterized by a high temporal and spatial resolution, is operating in real time. Different coupled models were considered to reproduce the selected events, in order to test and compare their reliability and efficiency. Specifically, two semi

  19. Plasmonics: Loss and gain

    NASA Astrophysics Data System (ADS)

    Oulton, Rupert F.

    2012-04-01

    Providing sufficient gain to overcome loss remains a fundamental challenge for light amplification in miniaturized plasmonic devices. Ongoing research gives hope for a cautious but optimistic outlook.

  20. A single amino acid substitution in a chitinase of the legume Medicago truncatula is sufficient to gain Nod-factor hydrolase activity.

    PubMed

    Zhang, Lan-Yue; Cai, Jie; Li, Ru-Jie; Liu, Wei; Wagner, Christian; Wong, Kam-Bo; Xie, Zhi-Ping; Staehelin, Christian

    2016-07-01

    The symbiotic interaction between nitrogen-fixing rhizobia and legumes depends on lipo-chitooligosaccharidic Nod-factors (NFs). The NF hydrolase MtNFH1 of Medicago truncatula is a symbiotic enzyme that hydrolytically inactivates NFs with a C16 : 2 acyl chain produced by the microsymbiont Sinorhizobium meliloti 1021. MtNFH1 is related to class V chitinases (glycoside hydrolase family 18) but lacks chitinase activity. Here, we investigated the substrate specificity of MtNFH1-related proteins. MtCHIT5a and MtCHIT5b of M. truncatula as well as LjCHIT5 of Lotus japonicus showed chitinase activity, suggesting a role in plant defence. The enzymes failed to hydrolyse NFs from S. meliloti. NFs from Rhizobium leguminosarum with a C18 : 4 acyl moiety were neither hydrolysed by these chitinases nor by MtNFH1. Construction of chimeric proteins and further amino acid replacements in MtCHIT5b were performed to identify chitinase variants that gained the ability to hydrolyse NFs. A single serine-to-proline substitution was sufficient to convert MtCHIT5b into an NF-cleaving enzyme. MtNFH1 with the corresponding proline-to-serine substitution failed to hydrolyse NFs. These results are in agreement with a substrate-enzyme model that predicts NF cleavage when the C16 : 2 moiety is placed into a distinct fatty acid-binding cleft. Our findings support the view that MtNFH1 evolved from the ancestral MtCHIT5b by gene duplication and subsequent symbiosis-related neofunctionalization. PMID:27383628

  1. A single amino acid substitution in a chitinase of the legume Medicago truncatula is sufficient to gain Nod-factor hydrolase activity

    PubMed Central

    Zhang, Lan-Yue; Cai, Jie; Li, Ru-Jie; Liu, Wei; Wagner, Christian; Wong, Kam-Bo; Xie, Zhi-Ping; Staehelin, Christian

    2016-01-01

    The symbiotic interaction between nitrogen-fixing rhizobia and legumes depends on lipo-chitooligosaccharidic Nod-factors (NFs). The NF hydrolase MtNFH1 of Medicago truncatula is a symbiotic enzyme that hydrolytically inactivates NFs with a C16 : 2 acyl chain produced by the microsymbiont Sinorhizobium meliloti 1021. MtNFH1 is related to class V chitinases (glycoside hydrolase family 18) but lacks chitinase activity. Here, we investigated the substrate specificity of MtNFH1-related proteins. MtCHIT5a and MtCHIT5b of M. truncatula as well as LjCHIT5 of Lotus japonicus showed chitinase activity, suggesting a role in plant defence. The enzymes failed to hydrolyse NFs from S. meliloti. NFs from Rhizobium leguminosarum with a C18 : 4 acyl moiety were neither hydrolysed by these chitinases nor by MtNFH1. Construction of chimeric proteins and further amino acid replacements in MtCHIT5b were performed to identify chitinase variants that gained the ability to hydrolyse NFs. A single serine-to-proline substitution was sufficient to convert MtCHIT5b into an NF-cleaving enzyme. MtNFH1 with the corresponding proline-to-serine substitution failed to hydrolyse NFs. These results are in agreement with a substrate-enzyme model that predicts NF cleavage when the C16 : 2 moiety is placed into a distinct fatty acid-binding cleft. Our findings support the view that MtNFH1 evolved from the ancestral MtCHIT5b by gene duplication and subsequent symbiosis-related neofunctionalization. PMID:27383628

  2. Ciliary neurotrophic factor activates leptin-like pathways and reduces body fat, without cachexia or rebound weight gain, even in leptin-resistant obesity.

    PubMed

    Lambert, P D; Anderson, K D; Sleeman, M W; Wong, V; Tan, J; Hijarunguru, A; Corcoran, T L; Murray, J D; Thabet, K E; Yancopoulos, G D; Wiegand, S J

    2001-04-10

    Ciliary Neurotrophic Factor (CNTF) was first characterized as a trophic factor for motor neurons in the ciliary ganglion and spinal cord, leading to its evaluation in humans suffering from motor neuron disease. In these trials, CNTF caused unexpected and substantial weight loss, raising concerns that it might produce cachectic-like effects. Countering this possibility was the suggestion that CNTF was working via a leptin-like mechanism to cause weight loss, based on the findings that CNTF acts via receptors that are not only related to leptin receptors, but also similarly distributed within hypothalamic nuclei involved in feeding. However, although CNTF mimics the ability of leptin to cause fat loss in mice that are obese because of genetic deficiency of leptin (ob/ob mice), CNTF is also effective in diet-induced obesity models that are more representative of human obesity, and which are resistant to leptin. This discordance again raised the possibility that CNTF might be acting via nonleptin pathways, perhaps more analogous to those activated by cachectic cytokines. Arguing strongly against this possibility, we now show that CNTF can activate hypothalamic leptin-like pathways in diet-induced obesity models unresponsive to leptin, that CNTF improves prediabetic parameters in these models, and that CNTF acts very differently than the prototypical cachectic cytokine, IL-1. Further analyses of hypothalamic signaling reveals that CNTF can suppress food intake without triggering hunger signals or associated stress responses that are otherwise associated with food deprivation; thus, unlike forced dieting, cessation of CNTF treatment does not result in binge overeating and immediate rebound weight gain.

  3. Ciliary neurotrophic factor activates leptin-like pathways and reduces body fat, without cachexia or rebound weight gain, even in leptin-resistant obesity.

    PubMed

    Lambert, P D; Anderson, K D; Sleeman, M W; Wong, V; Tan, J; Hijarunguru, A; Corcoran, T L; Murray, J D; Thabet, K E; Yancopoulos, G D; Wiegand, S J

    2001-04-10

    Ciliary Neurotrophic Factor (CNTF) was first characterized as a trophic factor for motor neurons in the ciliary ganglion and spinal cord, leading to its evaluation in humans suffering from motor neuron disease. In these trials, CNTF caused unexpected and substantial weight loss, raising concerns that it might produce cachectic-like effects. Countering this possibility was the suggestion that CNTF was working via a leptin-like mechanism to cause weight loss, based on the findings that CNTF acts via receptors that are not only related to leptin receptors, but also similarly distributed within hypothalamic nuclei involved in feeding. However, although CNTF mimics the ability of leptin to cause fat loss in mice that are obese because of genetic deficiency of leptin (ob/ob mice), CNTF is also effective in diet-induced obesity models that are more representative of human obesity, and which are resistant to leptin. This discordance again raised the possibility that CNTF might be acting via nonleptin pathways, perhaps more analogous to those activated by cachectic cytokines. Arguing strongly against this possibility, we now show that CNTF can activate hypothalamic leptin-like pathways in diet-induced obesity models unresponsive to leptin, that CNTF improves prediabetic parameters in these models, and that CNTF acts very differently than the prototypical cachectic cytokine, IL-1. Further analyses of hypothalamic signaling reveals that CNTF can suppress food intake without triggering hunger signals or associated stress responses that are otherwise associated with food deprivation; thus, unlike forced dieting, cessation of CNTF treatment does not result in binge overeating and immediate rebound weight gain. PMID:11259650

  4. Ciliary neurotrophic factor activates leptin-like pathways and reduces body fat, without cachexia or rebound weight gain, even in leptin-resistant obesity

    PubMed Central

    Lambert, P. D.; Anderson, K. D.; Sleeman, M. W.; Wong, V.; Tan, J.; Hijarunguru, A.; Corcoran, T. L.; Murray, J. D.; Thabet, K. E.; Yancopoulos, G. D.; Wiegand, S. J.

    2001-01-01

    Ciliary Neurotrophic Factor (CNTF) was first characterized as a trophic factor for motor neurons in the ciliary ganglion and spinal cord, leading to its evaluation in humans suffering from motor neuron disease. In these trials, CNTF caused unexpected and substantial weight loss, raising concerns that it might produce cachectic-like effects. Countering this possibility was the suggestion that CNTF was working via a leptin-like mechanism to cause weight loss, based on the findings that CNTF acts via receptors that are not only related to leptin receptors, but also similarly distributed within hypothalamic nuclei involved in feeding. However, although CNTF mimics the ability of leptin to cause fat loss in mice that are obese because of genetic deficiency of leptin (ob/ob mice), CNTF is also effective in diet-induced obesity models that are more representative of human obesity, and which are resistant to leptin. This discordance again raised the possibility that CNTF might be acting via nonleptin pathways, perhaps more analogous to those activated by cachectic cytokines. Arguing strongly against this possibility, we now show that CNTF can activate hypothalamic leptin-like pathways in diet-induced obesity models unresponsive to leptin, that CNTF improves prediabetic parameters in these models, and that CNTF acts very differently than the prototypical cachectic cytokine, IL-1. Further analyses of hypothalamic signaling reveals that CNTF can suppress food intake without triggering hunger signals or associated stress responses that are otherwise associated with food deprivation; thus, unlike forced dieting, cessation of CNTF treatment does not result in binge overeating and immediate rebound weight gain. PMID:11259650

  5. Invention and Gain Analysis.

    ERIC Educational Resources Information Center

    Weber, Robert J.; Dixon, Stacey

    1989-01-01

    Gain analysis is applied to the invention of the sewing needle as well as different sewing implements and modes of sewing. The analysis includes a two-subject experiment. To validate the generality of gain heuristics and underlying switching processes, the invention of the assembly line is also analyzed. (TJH)

  6. Use of activated carbon as a support medium for H2S biofiltration and effect of bacterial immobilization on available pore surface.

    PubMed

    Ng, Y L; Yan, R; Chen, X G; Geng, A L; Gould, W D; Liang, D T; Koe, L C C

    2004-12-01

    The use of support media for the immobilization of microorganisms is widely known to provide a surface for microbial growth and a shelter that protects the microorganisms from inhibitory compounds. In this study, activated carbon is used as a support medium for the immobilization of microorganisms enriched from municipal sewage activated sludge to remove gas-phase hydrogen sulfide (H2S), a major odorous component of waste gas from sewage treatment plants. A series of designed experiments is used to examine the effect on bacteria-immobilized activated carbon (termed "biocarbon") due to physical adsorption, chemical reaction, and microbial degradation in the overall removal of H2S. H2S breakthrough tests are conducted with various samples, including microbe-immobilized carbon and Teflon discs, salts-medium-washed carbon, and ultra-pure water-washed carbon. The results show a higher removal capacity for the microbe-immobilized activated carbon compared with the activated carbon control in a batch biofilter column. The increase in removal capacity is attributed to the role played by the immobilized microorganisms in metabolizing adsorbed sulfur and sulfur compounds on the biocarbon, hence releasing the adsorption sites for further H2S uptake. The advantage for activated carbon serving as the support medium is to adsorb a high initial concentration of substrate and progressively release this for microbial degradation, hence acting as a buffer for the microorganisms. Results obtained from surface area and pore size distribution analyses of the biocarbon show a correlation between the available surface area and pore volume with the extent of microbial immobilization and H2S uptake. The depletion of surface area and pore volume is seen as one of the factors which cause the onset of column breakthrough. Microbial growth retardation is due to the accumulation of metabolic products (i.e., sulfuric acid); and a lack of water and nutrient salts in the batch biofilter are other

  7. Gain-assisted control of the Goos-Haenchen shift

    SciTech Connect

    Ziauddin,; Qamar, Sajid

    2011-11-15

    A gain-assisted model is considered to study the Goos-Haenchen (GH) shift behavior in the reflected and transmitted light. In this model, a probe light is incident on a cavity containing three-level dilute gaseous atomic medium. The atom-field interaction follows two-photon Raman transitions, and the dielectric susceptibility of the medium exhibits dispersion and gain properties [L. J. Wang, A. Kuzmich, and A. Dogariu, Nature (London) 406, 227 (2000)]. Under appropriate conditions, two gain peaks are observed with anomalous dispersion between the peaks, whereas normal dispersion can be observed at and around the gain maxima. The manipulation of the detuning associated with the probe light field which interacts with the intracavity medium during its propagation through the cavity can lead to a control over negative and positive GH shift in the reflected and transmitted light beam via the anomalous and normal dispersion of the medium.

  8. Preventing Weight Gain

    MedlinePlus

    ... If this is the case, preventing further weight gain is a worthy goal. As people age, their body composition gradually shifts — the proportion of muscle decreases and the proportion of fat increases. This ...

  9. Oxidation-reduction potential changes in aeration tanks and microprofiles of activated sludge floc in medium- and low-strength wastewaters.

    PubMed

    Li, Baikun; Bishop, Paul L

    2004-01-01

    Real-time control of aeration tank operation is key to high-efficiency pollutant removal and energy savings. One of the aims of this study was to examine the potential for using redox potential (oxidation-reduction potential [ORP]) to indicate wastewater quality online in aeration tanks treating medium (chemical oxygen demand [COD] of 70 to 150 mg/L) and low (COD of 15 to 30 mg/L) pollutant-concentration wastewaters. The field-scale data provide a good relationship between ORP values and nutrient removal along the length of the aeration tanks. The ORP values increased dramatically as organic matter was removed along the aeration tanks, indicating the improvement of the bulk liquor redox status. Dissolved oxygen higher than 1.0 mg/L was necessary for good biodegradation and improvement of the liquid redox status. Nitrification occurred at higher ORP values (380 to 420 mV) than was the case for organic substrate oxidation (250 to 300 mV). The microprofiles obtained from microelectrode measurements substantiate the heterogeneity of the microbial processes inside activated sludge flocs. Because of microbial oxygen utilization, the aerobic region in the activated sludge floc was limited to the top layer (0.1 to 0.2 mm) of the activated sludge aggregate present in medium-strength wastewater, with an anoxic zone dominating inside the flocs. When dissolved oxygen in the bulk water was higher than 4.0 mg/L, the anoxic zone inside the floc disappeared. At low wastewater pollutant concentrations, the ORP and dissolved oxygen inside the activated sludge aggregates were higher than those from medium-strength wastewater. The prospect of using ORP as an online control approach for aeration tank operation and the potential reasons for activated sludge floc size varying with pollutant strengths are also discussed.

  10. Microbial activity in argillite waste storage cells for the deep geological disposal of French bituminous medium activity long lived nuclear waste: Impact on redox reaction kinetics and potential

    NASA Astrophysics Data System (ADS)

    Albrecht, A.; Leone, L.; Charlet, L.

    2009-04-01

    Micro-organisms are ubiquitous and display remarkable capabilities to adapt and survive in the most extreme environmental conditions. It has been recognized that microorganisms can survive in nuclear waste disposal facilities if the required major (P, N, K) and trace elements, a carbon and energy source as well as water are present. The space constraint is of particular interest as it has been shown that bacteria do not prosper in compacted clay. An evaluation of the different types of French medium and high level waste, in a clay-rich host rock storage environment at a depth between 500 and 600 m, has shown that the bituminous waste is the most likely candidate to accommodate significant microbial activity. The waste consists of a mixture of bitumen (source of bio-available organic matter and H2 as a consequence of its degradation and radiolysis) and nitrates and sulphates kept in a stainless steel container. The assumption, that microbes only have an impact on reaction kinetics needs to be reassessed in the case where nitrates and sulphates are present since both are known not to react at low temperatures without bacterial catalysis. The additional impact of both oxy-anions and their reduced species on redox conditions, radionuclide speciation and mobility gives this evaluation their particular relevance. Storage architecture proposes four primary waste containers positioned into armoured cement over packs and placed with others into the waste storage cell itself composed of a cement mantle enforcing the argillite host rock, the latter being characterized by an excavation damaged zone constricted both in space and in time and a pristine part of 60 m thickness. Bacterial activity within the waste and within the pristine argillite is disregarded because of the low water activity (< 0.7) and the lack of space, respectively. The most probable zones of microbial activity, those likely to develop sustainable biofilms are within the interface zones. A major restriction

  11. ACTIVE MEDIA: Pump and amplification dynamics of gamma rays in a nuclear medium with the hidden population inversion

    NASA Astrophysics Data System (ADS)

    Rivlin, Lev A.

    2009-12-01

    The features of the pump dynamics of isomeric nuclei excited by X-rays of a repetitively pulsed relativistic electron beam followed by the production of a medium with the negative absorption of gamma quanta are analysed. In the extended nuclear medium, the pump excites a travelling hidden-population-inversion wave with the anisotropic gamma amplification, which becomes positive in the case of the excess over the critical pump parameter equal to the product of the peak spectral power density of the X-ray source and the relative duration of an ultrashort relativistic electron bunch. In the alternative scheme with orthogonal directions of pumping X-rays and a flux of amplified gamma quanta, the absence of the amplification anisotropy opens up the possibility for constructing a standard two-mirror resonator with Bragg single-crystal reflectors. The critical peak value of the spectral pump power density is compared with the known characteristics of relativistic-electron X-ray sources by examples of some nuclides.

  12. Scintillator high-gain avalanche rushing photoconductor active-matrix flat panel imager: Zero-spatial frequency x-ray imaging properties of the solid-state SHARP sensor structure

    SciTech Connect

    Wronski, M.; Zhao, W.; Tanioka, K.; DeCrescenzo, G.; Rowlands, J. A.

    2012-11-15

    Purpose: The authors are investigating the feasibility of a new type of solid-state x-ray imaging sensor with programmable avalanche gain: scintillator high-gain avalanche rushing photoconductor active matrix flat panel imager (SHARP-AMFPI). The purpose of the present work is to investigate the inherent x-ray detection properties of SHARP and demonstrate its wide dynamic range through programmable gain. Methods: A distributed resistive layer (DRL) was developed to maintain stable avalanche gain operation in a solid-state HARP. The signal and noise properties of the HARP-DRL for optical photon detection were investigated as a function of avalanche gain both theoretically and experimentally, and the results were compared with HARP tube (with electron beam readout) used in previous investigations of zero spatial frequency performance of SHARP. For this new investigation, a solid-state SHARP x-ray image sensor was formed by direct optical coupling of the HARP-DRL with a structured cesium iodide (CsI) scintillator. The x-ray sensitivity of this sensor was measured as a function of avalanche gain and the results were compared with the sensitivity of HARP-DRL measured optically. The dynamic range of HARP-DRL with variable avalanche gain was investigated for the entire exposure range encountered in radiography/fluoroscopy (R/F) applications. Results: The signal from HARP-DRL as a function of electric field showed stable avalanche gain, and the noise associated with the avalanche process agrees well with theory and previous measurements from a HARP tube. This result indicates that when coupled with CsI for x-ray detection, the additional noise associated with avalanche gain in HARP-DRL is negligible. The x-ray sensitivity measurements using the SHARP sensor produced identical avalanche gain dependence on electric field as the optical measurements with HARP-DRL. Adjusting the avalanche multiplication gain in HARP-DRL enabled a very wide dynamic range which encompassed all

  13. Mode-medium instability in an unstable resonator

    NASA Technical Reports Server (NTRS)

    Sung, C. C.; Li, Y. Q.; Smithers, Martin E.

    1988-01-01

    The mode-medium instability of an active medium in an unstable resonator is investigated. The asymptotic solution due to Horwitz (1973), valid for large Fresnel numbers in an empty cavity, is modified by introducing gain/phase sheets in front of the resonator mirrors. The effect of medium coupling to the mode in the cavity is obtained by introducing a general time-independent Green's function in the Fox-Li (1961) formulation. The time evolution is then obtained by repeated integration of the beam propagation in the cavity. The diffractive terms are shown to grow rapidly at the expense of the geometric term. This instability responsible for the deterioration of the beam quality is studied numerically for a CO2 lasing system as an example.

  14. Gain-enhanced hyperbolic metamaterials at telecommunication frequencies (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Smalley, Joseph S. T.; Vallini, Felipe; Kante, Boubacar; Shahin, Shiva; Riley, Conor; Fainman, Yeshaiahu

    2015-09-01

    Using effective medium theory (EMT), Bloch's theorem (BT), and the transfer matrix method (TMM), we analyze the possibility of gain-enhanced transmission in metamaterials with hyperbolic dispersion at telecommunication frequencies. We compare different combinations of dissipative metals and active dielectrics, including noble metals, transparent conducting oxides (TCO), III-V compounds, and solid-state dopants. We find that both indium gallium arsenide phosphide (InGaAsP) and erbium-doped silica (Er:SiO2), when combined with silver, show promise as a platform for demonstration of pump-dependent transmission. On the other hand, when these active dielectrics are combined with aluminum-doped zinc oxide (AZO), a low-loss TCO, gain-enhanced transmission is negligible. Results based on EMT are compared to the more accurate BT and TMM. When losses are ignored, quantitative agreement between these analytical techniques is observed near the center of the first Brillouin zone of a one-dimensional periodic structure. Including realistic levels of loss and gain, however, EMT predictions become overly optimistic compared to BT and TMM. We also discuss the limitations to assumptions inherent to EMT, BT, and TMM, and suggest avenues for future analysis.

  15. Plasma-tail activity and the interplanetary medium at Halley's Comet during Armada Week: 6-14 March 1986

    NASA Technical Reports Server (NTRS)

    Niedner, Malcolm B., Jr.; Schwingenschuh, Konrad; Hoeksema, J. Todd; Dryer, Murray; Mcintosh, Patrick S.

    1987-01-01

    The encounters of five spacecraft with Halley's Comet during 6-14 March 1986 offered a unique opportunity to calibrate the solar-wind interaction with cometary plasmas as recorded by remote wide-field and narrow-field/narrowband imaging. Perhaps not generally recognized in the comet community is the additional opportunity offered by the Halley Armada to study the structure of the solar-wind and interplanetary magnetic field (IMF) in three dimensions using five sets of data obtained over similar time intervals and heliocentric distances, but at somewhat different heliolatitudes. In fact, the two problems, i.e., comet physics and the structure of the interplanetary medium, are coupled if one wants to understand what conditions pertained at the comet between the encounters. This relationship is discussed.

  16. Formation and catalytic activity of high molecular weight soluble polymers produced by heating amino acids in a modified sea medium

    NASA Astrophysics Data System (ADS)

    Okihana, Hiroyuki

    1982-06-01

    Eighteen protein amino acids with milk casein composition were heated in a modified sea medium. Marigranules were formed in the precipitates and soluble polymers were formed in the supernatant. Time course of the reaction (ultraviolet spectra, the concentration of metal ions, and the concentration of amino acids in the supernatant) were measured. The time course of the formation of the soluble polymers was also studied by Bio-Gel P-2 column. High molecular weight soluble polymers (HMWSP) were separated from low molecular weight ones by dialysis. It was shown that these polymers catalyzed the dehydrogenation of NADH. These polymers also catalyzed the coupled reaction between dehydrogenation of NADH and reduction of resazurin. This coupled reaction was accelerated by the light.

  17. The effects of physical activity interventions on preventing weight gain and the effects on body composition in young adults with intellectual disabilities: systematic review and meta-analysis of randomized controlled trials.

    PubMed

    Harris, L; Hankey, C; Murray, H; Melville, C

    2015-08-01

    The aim of this study was to examine the literature on randomized controlled trials examining the efficacy of physical activity interventions to prevent weight gain and the effects on body composition in young adults with intellectual disabilities.A systematic search of Medline, Emabse, CINHAL, PsychINFO, Cochrane library and ERIC was conducted from 1946 to September 2014. Eligibility criteria included; randomized controlled trials of a physical activity intervention: objective measure of body weight and body composition; young adults (age range 16-24 years) with intellectual disabilities. Six studies met the eligibility criteria. The interventions varied in their prescription of physical activity including aerobic and strength-based activities. The mean duration of the interventions was 15.3 (range 10-21 weeks). There was no significant effect of physical activity interventions on body weight (weighted mean difference: -0.17 kg, 95% confidence interval, -1.04 kg to 0.72 kg) and body composition outcomes. The meta-analysis showed that physical activity interventions did not prevent weight gain in young adults with intellectual disabilities. Published studies are inadequate to form firm conclusions. Future longer term studies of interventions specifically designed for this population group are required to elucidate the effects of physical activity interventions on body composition and the prevention of weight gain in young adults with intellectual disabilities.

  18. DNA polymorphisms and transcript abundance of PRKAG2 and phosphorylated AMP-activated protein kinase in the rumen are associated with gain and feed intake in beef steers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Beef steers with variation in feed efficiency phenotypes were evaluated previously on a high density SNP panel. Ten markers from rs110125325-rs41652818 on bovine chromosome 4 were associated with average daily gain (ADG). To identify the gene(s) in this 1.2Mb region responsible for variation in AD...

  19. Administration of activated glial condition medium in the nucleus accumbens extended extinction and intensified reinstatement of methamphetamine-induced conditioned place preference.

    PubMed

    Arezoomandan, Reza; Moradi, Marzieh; Attarzadeh-Yazdi, Ghassem; Tomaz, Carlos; Haghparast, Abbas

    2016-07-01

    Methamphetamine (METH) is a psychostimulant drug with significant abuse potential and neurotoxic effects. A high percentage of users relapse to use after detoxification and no effective medication has been developed for treatment of METH addiction. Developing evidences indicated the role of glial cells in drugs abused related phenomena. However, little is known about the role of these cells in the maintenance and reinstatement of METH-seeking behaviors. Therefore, the current study was conducted to clarify the role of glial cells in the maintenance and reinstatement of METH-induced conditioned place preference (CPP) in rats. Astrocyte condition medium (ACM) and neuroglia conditioned medium (NCM) are liquid mediums prepared from primary astrocyte and neuroglia cells. These mediums seem to contain many factors that release by glia cells. CPP was induced by systemic administration of METH (1mg/kg for 5days, s.c.). Following the establishment of CPP, the rats were given daily bilateral injections (0.5μl/side) of either vehicle, ACM or NCM into the nucleus accumbens (NAc) and then were tested for the maintenance and reinstatement. Intra-NAc administration of ACM treated with METH, could extend the extinction period and also, intensified the magnitude of METH reinstatement. Furthermore, intra-accumbal administration of NCM treated with METH notably delayed the extinction period by four days and significantly increased the magnitude of CPP score in the reinstatement phase compared to the post-test phase. Collectively, these findings suggested that activation of glial cells may be involved in the maintenance and reinstatement of METH-seeking behaviors. It provides new evidence that glia cells might be considered as a potential target for the treatment of METH addiction. PMID:27346277

  20. Use of a glass bead-containing liquid medium for efficient production of a soil-free culture with polychlorinated biphenyl-dechlorination activity.

    PubMed

    Suzuki, Daisuke; Baba, Daisuke; Satheeja Santhi, Velayudhan; Jebakumar Solomon, Robinson David; Katayama, Arata

    2013-08-01

    We established a soil-free culture capable of dechlorinating polychlorinated biphenyls (PCBs) in Kanechlor-300 and Kanechlor-400 by establishing a PCB-dechlorinating soil culture in liquid medium containing 0.5 mm glass beads. PCB-dechlorination activity in liquid cultures with glass beads appeared to depend on the size of the glass beads, and soil-free cultures with 0.05-, 1.0- or 2.0 mm glass beads did not dechlorinate PCBs. Soil-free culture without glass beads also failed to dechlorinate PCBs. The soil-free culture containing 0.5 mm glass beads dechlorinated 42.6 ± 12.0 mol% in total PCBs. This soil-free culture was more effective than soil culture for dechlorinating PCBs ranging from dichlorinated PCBs to tetrachlorinated PCBs. Clone analysis of the 16S rRNA gene sequences showed that one of the predominant groups of microorganisms in the soil-free culture comprised heat-tolerant and spore-forming bacteria from the phylum Firmicutes. Heat treatment (100 °C, 10 min) did not destroy the PCB-dechlorination activity of the soil-free culture with glass beads. These results suggest that unknown species of the phylum Firmicutes were involved in PCB dechlorination in the soil-free culture. In this study, we succeeded in using a liquid medium containing glass beads as an inorganic soil substitute and showed that such a medium enhances PCB-dechlorination activity. Our study provides valuable information for developing PCB-bioremediation techniques using dechlorinating bacteria in anoxic contaminated soils and sediments.

  1. Receiver Gain Modulation Circuit

    NASA Technical Reports Server (NTRS)

    Jones, Hollis; Racette, Paul; Walker, David; Gu, Dazhen

    2011-01-01

    A receiver gain modulation circuit (RGMC) was developed that modulates the power gain of the output of a radiometer receiver with a test signal. As the radiometer receiver switches between calibration noise references, the test signal is mixed with the calibrated noise and thus produces an ensemble set of measurements from which ensemble statistical analysis can be used to extract statistical information about the test signal. The RGMC is an enabling technology of the ensemble detector. As a key component for achieving ensemble detection and analysis, the RGMC has broad aeronautical and space applications. The RGMC can be used to test and develop new calibration algorithms, for example, to detect gain anomalies, and/or correct for slow drifts that affect climate-quality measurements over an accelerated time scale. A generalized approach to analyzing radiometer system designs yields a mathematical treatment of noise reference measurements in calibration algorithms. By treating the measurements from the different noise references as ensemble samples of the receiver state, i.e. receiver gain, a quantitative description of the non-stationary properties of the underlying receiver fluctuations can be derived. Excellent agreement has been obtained between model calculations and radiometric measurements. The mathematical formulation is equivalent to modulating the gain of a stable receiver with an externally generated signal and is the basis for ensemble detection and analysis (EDA). The concept of generating ensemble data sets using an ensemble detector is similar to the ensemble data sets generated as part of ensemble empirical mode decomposition (EEMD) with exception of a key distinguishing factor. EEMD adds noise to the signal under study whereas EDA mixes the signal with calibrated noise. It is mixing with calibrated noise that permits the measurement of temporal-functional variability of uncertainty in the underlying process. The RGMC permits the evaluation of EDA by

  2. Optimization of Liquid Fermentation Medium for Production of Inonotus sanghuang (Higher Basidiomycetes) Mycelia and Evaluation of their Mycochemical Contents and Antioxidant Activities.

    PubMed

    Tian, Xue-Mei; Dai, Yu-Cheng; Song, Ai-Rong; Xu, Kun; Ng, Lean Teik

    2015-01-01

    Inonotus sanghuang, an authentic "Sanghuang" mushroom used in traditional Chinese medicine, is known to possess important pharmacological activities. In this study, we aimed to optimize the liquid fermentation medium for I. sanghuang mycelial production and to determine the effects of two-stage cultivation (shake and static) on the yield of total flavonoids, total phenolics, and polysaccharides, as well as the antioxidant activities of I. sanghuang mycelial extracts (ISME). Under an optimized medium composition (38.96 g/L of corn flour, 4.15 g/L of yeast extract, 20.55 g/L of bran and pH 6.39), the predicted and experimental optimal mycelial biomasses were 17.60 g/L and 18.33±0.86 g/L, respectively. The results of two-stage cultivation showed that contents of total flavonoids and total phenolics in mycelia increased by 37.92% and 77.27%, respectively. However, irregular polysaccharide contents were noted throughout the experimental period. Antioxidant assays showed that ISME possessed good free-radical scavenging activity, which is mainly contributed by polyphenolic-type metabolites.

  3. Optimization of Liquid Fermentation Medium for Production of Inonotus sanghuang (Higher Basidiomycetes) Mycelia and Evaluation of their Mycochemical Contents and Antioxidant Activities.

    PubMed

    Tian, Xue-Mei; Dai, Yu-Cheng; Song, Ai-Rong; Xu, Kun; Ng, Lean Teik

    2015-01-01

    Inonotus sanghuang, an authentic "Sanghuang" mushroom used in traditional Chinese medicine, is known to possess important pharmacological activities. In this study, we aimed to optimize the liquid fermentation medium for I. sanghuang mycelial production and to determine the effects of two-stage cultivation (shake and static) on the yield of total flavonoids, total phenolics, and polysaccharides, as well as the antioxidant activities of I. sanghuang mycelial extracts (ISME). Under an optimized medium composition (38.96 g/L of corn flour, 4.15 g/L of yeast extract, 20.55 g/L of bran and pH 6.39), the predicted and experimental optimal mycelial biomasses were 17.60 g/L and 18.33±0.86 g/L, respectively. The results of two-stage cultivation showed that contents of total flavonoids and total phenolics in mycelia increased by 37.92% and 77.27%, respectively. However, irregular polysaccharide contents were noted throughout the experimental period. Antioxidant assays showed that ISME possessed good free-radical scavenging activity, which is mainly contributed by polyphenolic-type metabolites. PMID:26559702

  4. Random lasing in a nanocomposite medium

    SciTech Connect

    Smetanin, Sergei N; Basiev, Tasoltan T

    2013-01-31

    The characteristics of a random laser based on a nanocomposite medium consisting of a transparent dielectric and scattering doped nanocrystals are calculated. It is proposed to use ytterbium laser media with a high concentration of active ions as nanocrystals and to use gases, liquids, or solid dielectrics with a refractive index lower than that of nanocrystals as dielectric matrices for nanocrystals. Based on the concept of nonresonant distributed feedback due to the Rayleigh scattering, an expression is obtained for the minimum length of a nanocomposite laser medium at which the random lasing threshold is overcome. Expressions are found for the critical (maximum) and the optimal size of nanocrystals, as well as for the optimal relative refractive index of nanocomposites that corresponds not only to the maximum gain but also to the minimum of the medium threshold length at the optimal size of nanocrystals. It is shown that the optimal relative refractive index of a nanocomposite increases with increasing pump level, but is independent of the other nanocomposite parameters. (nanocomposites)

  5. Production of extracellular proteolytic activity by Histoplasma capsulatum grown in Histoplasma-macrophage medium is limited to restriction fragment length polymorphism class 1 isolates.

    PubMed

    Zarnowski, Robert; Connolly, Patricia A; Wheat, L Joseph; Woods, Jon P

    2007-09-01

    Extracellular proteolytic activity was studied for 28 strains of Histoplasma capsulatum var. capsulatum and 2 strains of H. capsulatum var. duboisii. Secreted protease activity assessed by skim milk agarose clearance was limited solely to H. capsulatum var. capsulatum restriction fragment length polymorphism (RFLP) class 1 strains. There was a difference in proteolytic activity levels among class 1 strains. Extracellular proteolytic activity was further determined during growth of those strains in liquid medium using azodye-impregnated protein substrates. In general, the highest activities were measured when azocollagen was used, whereas azocasein and azoalbumin were cleaved less efficiently. The activity was inhibited by phenylmethylsulfonyl fluoride, 4-(2-aminoethyl) benzenesulfonyl fluoride, antipain, and chymostatin, indicating, thereby, the presence of chymotrypsin-like serine proteases. Chromatographic analyses as well as variable substrate use at different culture times revealed production of at least 2 different enzyme pools of the same serine-like protease family. Our results demonstrate a distinctive ability of RFLP class 1 isolates to produce and secrete serine proteinase-type activity. This peculiarity may be relevant to the biology and pathogenesis of this particular clade of H. capsulatum isolates. Overall, the feature of extracellular proteolytic activity production enables a convenient and unequivocal identification of RFLP class 1 isolates and, thereby, can be used in H. capsulatum strain differentiation and typing. PMID:17509799

  6. Activator-inhibitor coupling between Rho signaling and actin assembly make the cell cortex an excitable medium

    PubMed Central

    Bement, William M.; Leda, Marcin; Moe, Alison M.; Kita, Angela M.; Larson, Matthew E.; Golding, Adriana E.; Pfeuti, Courtney; Su, Kuan-Chung; Miller, Ann L.; Goryachev, Andrew B.; von Dassow, George

    2016-01-01

    Animal cell cytokinesis results from patterned activation of the small GTPase Rho, which directs assembly of actomyosin in the equatorial cortex. Cytokinesis is restricted to a portion of the cell cycle following anaphase onset in which the cortex is responsive to signals from the spindle. We show that shortly after anaphase onset oocytes and embryonic cells of frogs and echinoderms exhibit cortical waves of Rho activity and F-actin polymerization. The waves are modulated by cyclin-dependent kinase 1 (Cdk1) activity and require the Rho GEF (guanine nucleotide exchange factor), Ect2. Surprisingly, during wave propagation, while Rho activity elicits F-actin assembly, F-actin subsequently inactivates Rho. Experimental and modeling results show that waves represent excitable dynamics of a reaction diffusion system with Rho as the activator and F-actin the inhibitor. We propose that cortical excitability explains fundamental features of cytokinesis including its cell cycle regulation. PMID:26479320

  7. Effect of the dipole-dipole interaction of particles in an active medium on the character of superradiation

    SciTech Connect

    Berezovsky, V. V.; Men'shikov, L. I.; Oberg, S.; Latham, C. D.

    2008-07-15

    The motion of a system of interacting nonlinear charged oscillators is investigated numerically. Because of nonlinearity, the total collective electric field gives rise to a phasing effect-correlations in the phases of the oscillators. The consequence is superradiation-the enhanced spontaneous short-term emission of the energy stored in the oscillators. It is shown that the oscillations of the oscillators become stochastic because of the dipole-dipole interaction between them and their nearest neighbors. As a result, as the density of the oscillators increases, distant collective correlations are suppressed, superradiation ceases to be generated, and radiation is shielded in the medium. The phenomena considered in the present paper can play an important role in cyclotron emission from a plasma and thus should be taken into account in emission calculations. The process whereby the energy of the transverse electron motion in electron cooling devices decreases is analyzed as an example. This process occurs as a result of the development of cyclotron maser instability and has the nature of superradiation. The onset of correlations between individual electrons moving in their Larmor circles is the initial, linear stage of instability developing in the plasma. Superradiation is the final, nonlinear instability stage.

  8. Theory of noise in high-gain surface plasmon-polariton amplifiers incorporating dipolar gain media.

    PubMed

    De Leon, Israel; Berini, Pierre

    2011-10-10

    A theoretical analysis of noise in high-gain surface plasmon-polariton amplifiers incorporating dipolar gain media is presented. An expression for the noise figure is obtained in terms of the spontaneous emission rate into the amplified surface plasmon-polariton taking into account the different energy decay channels experienced by dipoles in close proximity to the metallic surface. Two amplifier structures are examined: a single-interface between a metal and a gain medium and a thin metal film bounded by identical gain media on both sides. A realistic configuration is considered where the surface plasmon-polariton undergoing amplification has a Gaussian field profile in the plane of the metal and paraxial propagation along the amplifier's length. The noise figure of these plasmonic amplifiers is studied considering three prototypical gain media with different permittivities. It is shown that the noise figure exhibits a strong dependance on the real part of the permittivities of the metal and gain medium, and that its minimum value is 4/π(∼3.53 dB). The origin of this minimum value is discussed. It is also shown that amplifier configurations supporting strongly confined surface plasmon-polaritons suffer from a large noise figure, which follows from an enhanced spontaneous emission rate due to the Purcell effect.

  9. Improvement of medium chain fatty acid content and antimicrobial activity of coconut oil via solid-state fermentation using a Malaysian Geotrichum candidum.

    PubMed

    Khoramnia, Anahita; Ebrahimpour, Afshin; Ghanbari, Raheleh; Ajdari, Zahra; Lai, Oi-Ming

    2013-01-01

    Coconut oil is a rich source of beneficial medium chain fatty acids (MCFAs) particularly lauric acid. In this study, the oil was modified into a value-added product using direct modification of substrate through fermentation (DIMOSFER) method. A coconut-based and coconut-oil-added solid-state cultivation using a Malaysian lipolytic Geotrichum candidum was used to convert the coconut oil into MCFAs-rich oil. Chemical characteristics of the modified coconut oils (MCOs) considering total medium chain glyceride esters were compared to those of the normal coconut oil using ELSD-RP-HPLC. Optimum amount of coconut oil hydrolysis was achieved at 29% moisture content and 10.14% oil content after 9 days of incubation, where the quantitative amounts of the modified coconut oil and MCFA were 0.330 mL/g of solid media (76.5% bioconversion) and 0.175 mL/g of solid media (53% of the MCO), respectively. MCOs demonstrated improved antibacterial activity mostly due to the presence of free lauric acid. The highest MCFAs-rich coconut oil revealed as much as 90% and 80% antibacterial activities against Staphylococcus aureus and Escherichia coli, respectively. The results of the study showed that DIMOSFER by a local lipolytic G. candidum can be used to produce MCFAs as natural, effective, and safe antimicrobial agent. The produced MCOs and MCFAs could be further applied in food and pharmaceutical industries.

  10. Improvement of Medium Chain Fatty Acid Content and Antimicrobial Activity of Coconut Oil via Solid-State Fermentation Using a Malaysian Geotrichum candidum

    PubMed Central

    Khoramnia, Anahita; Ebrahimpour, Afshin; Ghanbari, Raheleh; Ajdari, Zahra; Lai, Oi-Ming

    2013-01-01

    Coconut oil is a rich source of beneficial medium chain fatty acids (MCFAs) particularly lauric acid. In this study, the oil was modified into a value-added product using direct modification of substrate through fermentation (DIMOSFER) method. A coconut-based and coconut-oil-added solid-state cultivation using a Malaysian lipolytic Geotrichum candidum was used to convert the coconut oil into MCFAs-rich oil. Chemical characteristics of the modified coconut oils (MCOs) considering total medium chain glyceride esters were compared to those of the normal coconut oil using ELSD-RP-HPLC. Optimum amount of coconut oil hydrolysis was achieved at 29% moisture content and 10.14% oil content after 9 days of incubation, where the quantitative amounts of the modified coconut oil and MCFA were 0.330 mL/g of solid media (76.5% bioconversion) and 0.175 mL/g of solid media (53% of the MCO), respectively. MCOs demonstrated improved antibacterial activity mostly due to the presence of free lauric acid. The highest MCFAs-rich coconut oil revealed as much as 90% and 80% antibacterial activities against Staphylococcus aureus and Escherichia coli, respectively. The results of the study showed that DIMOSFER by a local lipolytic G. candidum can be used to produce MCFAs as natural, effective, and safe antimicrobial agent. The produced MCOs and MCFAs could be further applied in food and pharmaceutical industries. PMID:23971051

  11. Evaluation of antibacterial activity of selected Iranian essential oils against Staphylococcus aureus and Escherichia coli in nutrient broth medium.

    PubMed

    Mohsenzadeh, Mohammad

    2007-10-15

    The antibacterial effect of different concentrations (0.01 to 15%) of thyme (Thymus vulgaris), peppermint (Mentha piperita L.) caraway seed (Carum carvi), fennel (Foeniculum vulgar), tarragon (Artmesia dracunculus) and pennyroyal (Mentha pullegium) essential oils on the Staphylococcus aureus and Escherichia coli was studied in nutrient broth medium. The MIC values of peppermint, fennel, thyme, pennyroyal and caraway essential oils against Escherichia coli were 0.5 +/- 0.03, 1 +/- 0.03, 0.3 +/- 0.01, 0.7 +/- 0.03 and 0.6 +/- 0.02% and in contrast, for Staphylococcus aureus were 0.4 +/- 0.01, 2 +/- 0.13, 0.1 +/- 0.01, 0.5 +/- 0.02 and 0.5 +/- 0.02%, respectively. The MBC values of peppermint, fennel, thyme, pennyroyal and caraway essential oils for Escherichia coli were 0.7 +/- 0.02, 2 +/- 0.05, 0.5 +/- 0.02, 1 +/- 0.02 and 0.8 +/- 0.02 and for Staphylococcus aureus were 0.5 +/- 0.02, 4 +/- 0.26, 0.3 +/- 0.02, 0.7 +/- 0.02 and 0.6 +/- 0.01, respectively. Statistical evaluation of the results indicated that the essential oils of thyme (Thymus vulgaris) showed the broadest spectrum of action (p < 0.05). Essential oils of peppermint (Mentha piperita), caraway seed (Carum carvi), pennyroyal (Menthae pullegium) and fennel (Foeniculum vulgar) had moderate effect against tested microorganisms and in contrast, tarragon essential oil were less effective against tested microorganisms. In conclusion, essential oils of edible plants could be a potential source for inhibitory substances for some foodborne pathogens. Natural substances that extracted from plants have applications in controlling pathogens in foods.

  12. Temporal evolution of "automatic gain-scaling".

    PubMed

    Pruszynski, J Andrew; Kurtzer, Isaac; Lillicrap, Timothy P; Scott, Stephen H

    2009-08-01

    The earliest neural response to a mechanical perturbation, the short-latency stretch response (R1: 20-45 ms), is known to exhibit "automatic gain-scaling" whereby its magnitude is proportional to preperturbation muscle activity. Because gain-scaling likely reflects an intrinsic property of the motoneuron pool (via the size-recruitment principle), counteracting this property poses a fundamental challenge for the nervous system, which must ultimately counter the absolute change in load regardless of the initial muscle activity (i.e., show no gain-scaling). Here we explore the temporal evolution of gain-scaling in a simple behavioral task where subjects stabilize their arm against different background loads and randomly occurring torque perturbations. We quantified gain-scaling in four elbow muscles (brachioradialis, biceps long, triceps lateral, triceps long) over the entire sequence of muscle activity following perturbation onset-the short-latency response, long-latency response (R2: 50-75 ms; R3: 75-105 ms), early voluntary corrections (120-180 ms), and steady-state activity (750-1250 ms). In agreement with previous observations, we found that the short-latency response demonstrated substantial gain-scaling with a threefold increase in background load resulting in an approximately twofold increase in muscle activity for the same perturbation. Following the short-latency response, we found a rapid decrease in gain-scaling starting in the long-latency epoch ( approximately 75-ms postperturbation) such that no significant gain-scaling was observed for the early voluntary corrections or steady-state activity. The rapid decrease in gain-scaling supports our recent suggestion that long-latency responses and voluntary control are inherently linked as part of an evolving sensorimotor control process through similar neural circuitry.

  13. Novel As-doped, As and N-codoped carbon nanotubes as highly active and durable electrocatalysts for O2 reduction in alkaline medium

    NASA Astrophysics Data System (ADS)

    Liu, Ziwu; Li, Meng; Wang, Fang; Wang, Quan-De

    2016-02-01

    To develop more efficient metal-free cathode electrocatalysts for fuel cells, novel arsenic (As)-doped, As and N-codoped carbon nanotubes are synthesized by chemical vapor deposition in this work. The as-prepared As-containing carbon nanotubes exhibit significantly enhanced activity and long-term durability for the oxygen reduction reaction (ORR) in alkaline medium, indicating that the doping of As or codoping As with other heteroatoms into carbon matrix could improve the ORR activity of carbon materials due to the changes in electronic and physical properties of carbon nanotubes evidenced by density functional theory calculations. Moreover, As-containing carbon nanotubes also display much better methanol tolerance, showing a good potential application for future fuel cells.

  14. Amoco technique gains support

    SciTech Connect

    1995-10-01

    Amoco Corp.`s low-cost horizontal drilling technique and equipment are gaining acceptance in the oilpatch after five years of design and fine-tuning work. The system is purely mechanical, and it`s designed to operate with a workover rig instead of a drilling rig. It`s engineered to drill short-radius horizontal wells with lateral sup to 1,000 feet, so far.

  15. Spectroscopic properties of UV active medium Ce3+:LiSr0.8Ca0.2AlF6

    NASA Astrophysics Data System (ADS)

    Nizamutdinov, A. S.; Shavelev, A. A.; Marisov, M. A.; Semashko, V. V.

    2016-02-01

    The aim of this work is phase composition and near UV spectroscopic studies of UV active media in fluoride crystals with colquiriite structure, such as Ce3+:LiSr0.8Ca0.2AlF6. Colquiriite structure mixed crystals show higher segregation coefficient of Ce3+ activator ions than common LiCaAlF6 hosts. An important result is based on the fact that this enhancement was achieved for two types of Ce3+ centers in a multisite Ce:LiSr0.8Ca0.2AlF6 system. Thus, it provides a higher gain coefficient for the 5d-4f transitions of Ce3+ ions and it spans a wider continuous wavelength tuning range between 280 and 320 nm for tunable Ce:LiSr0.8Ca0.2AlF6 laser systems.

  16. Enhanced antibacterial activity of copper/copper oxide nanowires prepared by pulsed laser ablation in water medium

    NASA Astrophysics Data System (ADS)

    Swarnkar, R. K.; Pandey, J. K.; Soumya, K. K.; Dwivedi, P.; Sundaram, S.; Prasad, Sanjay; Gopal, R.

    2016-07-01

    Copper/copper oxide nanowires (NWs) are well known for its antibacterial activity against various pathogens. In the present study, we have shown the enhanced antibacterial activity of the NWs against gram-negative bacterial strains ( Escherichia coli, Pseudomonas aeruginosa and Salmonella typhi) and gram-positive bacterial strains ( Bacillus subtilis and Staphylococcus aureus). The increase in the activity is because of the shape and size of the colloidal NWs which were prepared at room temperature in a one-step process by pulsed laser ablation of copper metal target. The purity, shape and size of the colloidal NWs were well characterized by UV-visible absorption spectroscopy and transmission electron microscopy (TEM). The NWs were of diameters in the range of 15-30 nm and lengths ranging from 200 to 600 nm. The dose-dependent antibacterial activity of these NWs was found to be more effective against gram-negative bacteria compared to gram-positive bacteria. As gram-negative bacteria have thinner layer of cell wall made up of peptidoglycan possibly which makes them more susceptible to Cu/Cu2O NWs, Cu/Cu2O NWs can be a potent candidate to be used as bactericidal or as growth inhibitor.

  17. 75 FR 9431 - Small and Medium-Sized Enterprises: U.S. and EU Export Activities, and Barriers and Opportunities...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-02

    ... October 28, 2009 (74 FR 55581); December 1, 2009 (74 FR 62812); and December 11, 2009 (74 FR 65787). A... the Federal Register of February 4, 2010 (75 FR 5804). Washington Hearing: The rescheduled Washington... Government activity was cancelled due to a snow storm. Persons wishing to appear at the March 18...

  18. Improvement of the antifungal activity of lactic acid bacteria by addition to the growth medium of phenylpyruvic acid, a precursor of phenyllactic acid.

    PubMed

    Valerio, Francesca; Di Biase, Mariaelena; Lattanzio, Veronica M T; Lavermicocca, Paola

    2016-04-01

    The aim of the current study was to improve the antifungal activity of eight lactic acid bacterial (LAB) strains by the addition of phenylpyruvic acid (PPA), a precursor of the antifungal compound phenyllactic acid (PLA), to a defined growth medium (DM). The effect of PPA addition on the LABs antifungal activity related to the production of organic acids (PLA, d-lactic, l-lactic, acetic, citric, formic and 4-hydroxy-phenyllactic acids) and of other phenylpyruvic-derived molecules, was investigated. In the presence of PPA the inhibitory activity (expressed as growth inhibition percentage) against fungal bread contaminants Aspergillus niger and Penicillium roqueforti significantly increased and was, even if not completely, associated to PLA increase (from a mean value of 0.44 to 0.93 mM). While the inhibitory activity against Endomyces fibuliger was mainly correlated to the low pH and to lactic, acetic and p-OH-PLA acids. When the PCA analysis based on data of growth inhibition percentage and organic acid concentrations was performed, strains grown in DM+PPA separated from those grown in DM and the most active strains Lactobacillus plantarum 21B, Lactobacillus fermentum 18B and Lactobacillus brevis 18F grouped together. The antifungal activity resulted to be strain-related, based on a different mechanism of action for filamentous fungi and the yeast and was not exclusively associated to the increase of PLA. Therefore, a further investigation on the unique unidentified peak in HPLC-UV chromatograms, was performed by LC-MS/MS analysis. Actually, full scan mass spectra (negative ion mode) recorded at the retention time of the unknown compound, showed a main peak of m/z 291.0 which was consistent with the nominal mass of the molecular ion [M-H](-) of polyporic acid, a PPA derivative whose antifungal activity has been previously reported (Brewer et al., 1977). In conclusion, the addition of PPA to the growth medium contributed to improve the antifungal activity of LAB

  19. Improvement of the antifungal activity of lactic acid bacteria by addition to the growth medium of phenylpyruvic acid, a precursor of phenyllactic acid.

    PubMed

    Valerio, Francesca; Di Biase, Mariaelena; Lattanzio, Veronica M T; Lavermicocca, Paola

    2016-04-01

    The aim of the current study was to improve the antifungal activity of eight lactic acid bacterial (LAB) strains by the addition of phenylpyruvic acid (PPA), a precursor of the antifungal compound phenyllactic acid (PLA), to a defined growth medium (DM). The effect of PPA addition on the LABs antifungal activity related to the production of organic acids (PLA, d-lactic, l-lactic, acetic, citric, formic and 4-hydroxy-phenyllactic acids) and of other phenylpyruvic-derived molecules, was investigated. In the presence of PPA the inhibitory activity (expressed as growth inhibition percentage) against fungal bread contaminants Aspergillus niger and Penicillium roqueforti significantly increased and was, even if not completely, associated to PLA increase (from a mean value of 0.44 to 0.93 mM). While the inhibitory activity against Endomyces fibuliger was mainly correlated to the low pH and to lactic, acetic and p-OH-PLA acids. When the PCA analysis based on data of growth inhibition percentage and organic acid concentrations was performed, strains grown in DM+PPA separated from those grown in DM and the most active strains Lactobacillus plantarum 21B, Lactobacillus fermentum 18B and Lactobacillus brevis 18F grouped together. The antifungal activity resulted to be strain-related, based on a different mechanism of action for filamentous fungi and the yeast and was not exclusively associated to the increase of PLA. Therefore, a further investigation on the unique unidentified peak in HPLC-UV chromatograms, was performed by LC-MS/MS analysis. Actually, full scan mass spectra (negative ion mode) recorded at the retention time of the unknown compound, showed a main peak of m/z 291.0 which was consistent with the nominal mass of the molecular ion [M-H](-) of polyporic acid, a PPA derivative whose antifungal activity has been previously reported (Brewer et al., 1977). In conclusion, the addition of PPA to the growth medium contributed to improve the antifungal activity of LAB

  20. A rate equation approach to gain saturation effects in laser mode calculations

    NASA Technical Reports Server (NTRS)

    Roberts, Lila F.

    1990-01-01

    Space exploration and research require large amounts of power. Solar pumped laser systems have been shown to have the potential for meeting the performance requirements necessary for power transmission in space. The successful design of laser systems for these applications will depend, in part, on having a clear understanding of the development of the dynamical processes in the laser cavity and on the effects that changes in physical and design parameters have on laser performance. In particular, it is necessary to know the amplitude and phase distributions of the laser beam at the output aperture when steady state operation is achieved in order to determine the far-field power distribution. The output from the laser will depend on the active medium, the optical environment of the active material and on the gain distribution in the active region as laser action builds up and reaches steady state. An important component in the design process will be a realistic model of the active laser cavity. A computer model of the laser cavity, based on Huygens' principle was developed. The code calculates the amplitude and phase of an optical wave reflected back and forth between the mirrors of a laser cavity. The original code assumes a gain distribution which does not change with the buildup of oscillations in the cavity. A step in the direction of realism is the inclusion of a saturable gain medium in the cavity. The objective is to incorporate saturation effects into the existing computer model.

  1. Mechanism of the metallic metamaterials coupled to the gain material.

    PubMed

    Huang, Zhixiang; Droulias, Sotiris; Koschny, Thomas; Soukoulis, Costas M

    2014-11-17

    We present evidence of strong coupling between the gain material and the metallic metamaterials. It is of vital importance to understand the mechanism of the coupling of metamaterials with the gain medium. Using a four-level gain system, the numerical pump-probe experiments are performed in several configurations (split-ring resonators (SRRs), inverse SRRs and fishnets) of metamaterials, demonstrating reduction of the resonator damping in all cases and hence the possibility for loss compensation. We find that the differential transmittance ΔT/T can be negative in different SRR configurations, such as SRRs on the top of the gain substrate, gain in the SRR gap and gain covering the SRR structure, while in the fishnet metamaterial with gain ΔT/T is positive.

  2. [Diversity, relative abundance and activity patterns of medium and large mammals in a tropical deciduous forest in the Isthmus of Tehuantepec, Oaxaca, Mexico].

    PubMed

    Cortés-Marcial, Malinalli; Briones-Salas, Miguel

    2014-12-01

    The use of camera traps and mammal track search are complementary methods to monitoring species of which is not well documented their natural history, as in the case of medium and large mammals. To ensure its conservation and good management, it is necessary to generate information about the structure of the community and their populations. The objective of the present study was to estimate the diversity, relative abundance and activity patterns of medium and large mammals in a tropical deciduous forest located in the Isthmus of Tehuantepec, Oaxaca, Mexico. Samplings were conducted in three month intervals, from September 2011 to May 2013. We used photographic-sampling and track search, two complementary sampling methods. For photographic-sampling, 12 camera traps were placed covering an area of 60 km2, while for the tracks search a monthly tour of four line-transect surveys of three kilometers length each was undertaken. We obtained a total of 344 pictures with 5292 trap-days total sampling effort; in addition, 187 track records in a total of 144 km. With both methods we registered 21 species of mammals, in 13 families and seven orders, and five species resulted in new records to the area. The diversity index of Shannon-Wiener obtained with the method of tracks was H' = 2.41, while the most abundant species were Urocyon cinereoargen- teus (IAR = 0.23) and Pecari tajacu (IAR = 0.20). By the method of trap the most abundant species were P. tajacu (IAR = 2.62) and Nasua narica (IAR = 1.28). In terms of patterns of activity P. tajacu, N. narica and Odocoileus virginianus were primarily diurnal species; Canis latrans and Leopardus pardalis did not show preference for any schedule in particular, and Didelphis virginiana and Dasypus novemcinctus preferred to have nocturnal activity. This information can be of help to the creation of programs of management and conservation of mam- mals of medium and large in the Isthmus of Tehuantepec, Oaxaca, México.

  3. Helicopter high gain control

    NASA Technical Reports Server (NTRS)

    Cunningham, T. B.; Nunn, E. C.

    1979-01-01

    High gain control is explored through a design study of the CH-47B helicopter. The plans are designed to obtain the maximum bandwidth possible given the hardware constraints. Controls are designed with modal control theory to specific bandwidths and closed loop mode shapes. Comparisons are made to an earlier complementary filter approach. Bandwidth improvement by removal of limitations is explored in order to establish hardware and mechanization options. Improvements in the pitch axis control system and in the rate gyro sensor noise characteristics in all axes are discussed. The use of rotor state feedback is assessed.

  4. Smoking Cessation and Weight Gain.

    ERIC Educational Resources Information Center

    Hall, Sharon M.; And Others

    1986-01-01

    Investigated determinants of weight gain after quitting smoking in two smoking treatment outcome studies. Results indicated abstinence resulted in weight gain, and postquitting weight gain was predicted by pretreatment tobacco use, a history of weight problems, and eating patterns. Relapse to smoking did not follow weight gain. (Author/BL)

  5. Enhanced anti-oxidative activity and lignocellulosic ethanol production by biotin addition to medium in Pichia guilliermondii fermentation.

    PubMed

    Qi, Kai; Xia, Xiao-Xia; Zhong, Jian-Jiang

    2015-01-01

    Commercialization of lignocellulosic ethanol fermentation requires its high titer, but the reactive oxygen species (ROS) accumulation during the bioprocess damaged the cells and compromised this goal. To improve the cellular anti-oxidative activity during non-detoxified corncob residue hydrolysate fermentation, seed cells were prepared to possess a higher level of intracellular biotin pool (IBP), which facilitated the biosyntheses of catalase and porphyrin. As a result, the catalase activity increased by 1.3-folds compared to control while the ROS level reduced by 50%. Cell viability in high-IBP cells was 1.7-folds of control and the final ethanol titer increased from 31.2 to 41.8 g L(-1) in batch fermentation. The high-IBP cells were further used for repeated-batch fermentation in the non-detoxified lignocellulosic hydrolysate, and the highest titer and average productivity of ethanol reached 63.7 g L(-1) and 1.2 g L(-1)h(-1). The results were favorable to future industrial application of this lignocellulosic bioethanol process.

  6. Enhanced anti-oxidative activity and lignocellulosic ethanol production by biotin addition to medium in Pichia guilliermondii fermentation.

    PubMed

    Qi, Kai; Xia, Xiao-Xia; Zhong, Jian-Jiang

    2015-01-01

    Commercialization of lignocellulosic ethanol fermentation requires its high titer, but the reactive oxygen species (ROS) accumulation during the bioprocess damaged the cells and compromised this goal. To improve the cellular anti-oxidative activity during non-detoxified corncob residue hydrolysate fermentation, seed cells were prepared to possess a higher level of intracellular biotin pool (IBP), which facilitated the biosyntheses of catalase and porphyrin. As a result, the catalase activity increased by 1.3-folds compared to control while the ROS level reduced by 50%. Cell viability in high-IBP cells was 1.7-folds of control and the final ethanol titer increased from 31.2 to 41.8 g L(-1) in batch fermentation. The high-IBP cells were further used for repeated-batch fermentation in the non-detoxified lignocellulosic hydrolysate, and the highest titer and average productivity of ethanol reached 63.7 g L(-1) and 1.2 g L(-1)h(-1). The results were favorable to future industrial application of this lignocellulosic bioethanol process. PMID:25864029

  7. Activation of Plant Immune Responses by a Gain-of-Function Mutation in an Atypical Receptor-Like Kinase1[C][W][OA

    PubMed Central

    Bi, Dongling; Cheng, Yu Ti; Li, Xin; Zhang, Yuelin

    2010-01-01

    Arabidopsis (Arabidopsis thaliana) suppressor of npr1-1, constitutive1 (snc1) contains a gain-of-function mutation in a Toll/interleukin receptor-nucleotide binding site-leucine-rich repeat Resistance (R) protein and it has been a useful tool for dissecting R-protein-mediated immunity. Here we report the identification and characterization of snc4-1D, a semidominant mutant with snc1-like phenotypes. snc4-1D constitutively expresses defense marker genes PR1, PR2, and PDF1.2, and displays enhanced pathogen resistance. Map-based cloning of SNC4 revealed that it encodes an atypical receptor-like kinase with two predicted extracellular glycerophosphoryl diester phosphodiesterase domains. The snc4-1D mutation changes an alanine to threonine in the predicted cytoplasmic kinase domain. Wild-type plants transformed with the mutant snc4-1D gene displayed similar phenotypes as snc4-1D, suggesting that the mutation is a gain-of-function mutation. Epistasis analysis showed that NON-RACE-SPECIFIC DISEASE RESISTANCE1 is required for the snc4-1D mutant phenotypes. In addition, the snc4-1D mutant phenotypes are partially suppressed by knocking out MAP KINASE SUBSTRATE1, a positive defense regulator associated with MAP KINASE4. Furthermore, both the morphology and constitutive pathogen resistance of snc4-1D are partially suppressed by blocking jasmonic acid synthesis, suggesting that jasmonic acid plays an important role in snc4-1D-mediated resistance. Identification of snc4-1D provides us a unique genetic system for analyzing the signal transduction pathways downstream of receptor-like kinases. PMID:20508139

  8. Activation and repression of Epstein-Barr Virus and Kaposi's sarcoma-associated herpesvirus lytic cycles by short- and medium-chain fatty acids.

    PubMed

    Gorres, Kelly L; Daigle, Derek; Mohanram, Sudharshan; Miller, George

    2014-07-01

    The lytic cycles of Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV) are induced in cell culture by sodium butyrate (NaB), a short-chain fatty acid (SCFA) histone deacetylase (HDAC) inhibitor. Valproic acid (VPA), another SCFA and an HDAC inhibitor, induces the lytic cycle of KSHV but blocks EBV lytic reactivation. To explore the hypothesis that structural differences between NaB and VPA account for their functional effects on the two related viruses, we investigated the capacity of 16 structurally related short- and medium-chain fatty acids to promote or prevent lytic cycle reactivation. SCFAs differentially affected EBV and KSHV reactivation. KSHV was reactivated by all SCFAs that are HDAC inhibitors, including phenylbutyrate. However, several fatty acid HDAC inhibitors, such as isobutyrate and phenylbutyrate, did not reactivate EBV. Reactivation of KSHV lytic transcripts could not be blocked completely by any fatty acid tested. In contrast, several medium-chain fatty acids inhibited lytic activation of EBV. Fatty acids that blocked EBV reactivation were more lipophilic than those that activated EBV. VPA blocked activation of the BZLF1 promoter by NaB but did not block the transcriptional function of ZEBRA. VPA also blocked activation of the DNA damage response that accompanies EBV lytic cycle activation. Properties of SCFAs in addition to their effects on chromatin are likely to explain activation or repression of EBV. We concluded that fatty acids stimulate the two related human gammaherpesviruses to enter the lytic cycle through different pathways. Importance: Lytic reactivation of EBV and KSHV is needed for persistence of these viruses and plays a role in carcinogenesis. Our direct comparison highlights the mechanistic differences in lytic reactivation between related human oncogenic gammaherpesviruses. Our findings have therapeutic implications, as fatty acids are found in the diet and produced by the human microbiota. Small

  9. [Current status of occupational health activities and the way that occupational health services should be offered to small- and medium-scale enterprises].

    PubMed

    Kayashima, Kotaro

    2013-10-01

    Activating occupational safety and health activities among Small- and Medium-scale Enterprises (SMEs) is a major issue because more than 80% of Japanese workers belong to these enterprises, in which the number of workers are less than 300 people. However, as the size of the enterprise decreases, the occurrence of problems of safety and health management systems and safety and health activities increases. Reasons for this include both the limitations of investments shortages of human resources. Occupational health services in SMEs has been provided by the cooperation of the following institutions: public associations (such as Regional Occupational Health Centers, Occupational Health Promotion Centers, Japan Industrial Safety and Health Association (JISHA)), occupational health agencies which provide checkup services, health insurance associations, and regional medical services. In contrast to the low coverage of occupational health services among SMEs in Japan, there are some countries in Europe in which this coverage is almost 100%. This is because of the development of occupational health services outside the company. To show the benefits of the safety and health activities to managers of SMEs, and to motivate them to take advantage of the services, it is important to consider measurements. Also, establishing systems that provide those services, improving the quality of specialists such as occupational physicians, and educating human resources, are all necessary.

  10. [Current status of occupational health activities and the way that occupational health services should be offered to small- and medium-scale enterprises].

    PubMed

    Kayashima, Kotaro

    2013-10-01

    Activating occupational safety and health activities among Small- and Medium-scale Enterprises (SMEs) is a major issue because more than 80% of Japanese workers belong to these enterprises, in which the number of workers are less than 300 people. However, as the size of the enterprise decreases, the occurrence of problems of safety and health management systems and safety and health activities increases. Reasons for this include both the limitations of investments shortages of human resources. Occupational health services in SMEs has been provided by the cooperation of the following institutions: public associations (such as Regional Occupational Health Centers, Occupational Health Promotion Centers, Japan Industrial Safety and Health Association (JISHA)), occupational health agencies which provide checkup services, health insurance associations, and regional medical services. In contrast to the low coverage of occupational health services among SMEs in Japan, there are some countries in Europe in which this coverage is almost 100%. This is because of the development of occupational health services outside the company. To show the benefits of the safety and health activities to managers of SMEs, and to motivate them to take advantage of the services, it is important to consider measurements. Also, establishing systems that provide those services, improving the quality of specialists such as occupational physicians, and educating human resources, are all necessary. PMID:24107334

  11. Catalase activity is stimulated by H(2)O(2) in rich culture medium and is required for H(2)O(2) resistance and adaptation in yeast.

    PubMed

    Martins, Dorival; English, Ann M

    2014-01-01

    Catalases are efficient scavengers of H2O2 and protect cells against H2O2 stress. Examination of the H2O2 stimulon in Saccharomyces cerevisiae revealed that the cytosolic catalase T (Ctt1) protein level increases 15-fold on H2O2 challenge in synthetic complete media although previous work revealed that deletion of the CCT1 or CTA1 genes (encoding peroxisomal/mitochondrial catalase A) does not increase the H2O2 sensitivity of yeast challenged in phosphate buffer (pH 7.4). This we attributed to our observation that catalase activity is depressed when yeast are challenged with H2O2 in nutrient-poor media. Hence, we performed a systematic comparison of catalase activity and cell viability of wild-type yeast and of the single catalase knockouts, ctt1∆ and cta1∆, following H2O2 challenge in nutrient-rich medium (YPD) and in phosphate buffer (pH 7.4). Ctt1 but not Cta1 activity is strongly induced by H2O2 when cells are challenged in YPD but suppressed when cells are challenged in buffer. Consistent with the activity results, exponentially growing ctt1∆ cells in YPD are more sensitive to H2O2 than wild-type or cta1∆ cells, whereas in buffer all three strains exhibit comparable H2O2 hypersensitivity. Furthermore, catalase activity is increased during adaptation to sublethal H2O2 concentrations in YPD but not in buffer. We conclude that induction of cytosolic Ctt1 activity is vital in protecting yeast against exogenous H2O2 but this activity is inhibited by H2O2 when cells are challenged in nutrient-free media.

  12. Catalase activity is stimulated by H2O2 in rich culture medium and is required for H2O2 resistance and adaptation in yeast☆

    PubMed Central

    Martins, Dorival; English, Ann M.

    2014-01-01

    Catalases are efficient scavengers of H2O2 and protect cells against H2O2 stress. Examination of the H2O2 stimulon in Saccharomyces cerevisiae revealed that the cytosolic catalase T (Ctt1) protein level increases 15-fold on H2O2 challenge in synthetic complete media although previous work revealed that deletion of the CCT1 or CTA1 genes (encoding peroxisomal/mitochondrial catalase A) does not increase the H2O2 sensitivity of yeast challenged in phosphate buffer (pH 7.4). This we attributed to our observation that catalase activity is depressed when yeast are challenged with H2O2 in nutrient-poor media. Hence, we performed a systematic comparison of catalase activity and cell viability of wild-type yeast and of the single catalase knockouts, ctt1∆ and cta1∆, following H2O2 challenge in nutrient-rich medium (YPD) and in phosphate buffer (pH 7.4). Ctt1 but not Cta1 activity is strongly induced by H2O2 when cells are challenged in YPD but suppressed when cells are challenged in buffer. Consistent with the activity results, exponentially growing ctt1∆ cells in YPD are more sensitive to H2O2 than wild-type or cta1∆ cells, whereas in buffer all three strains exhibit comparable H2O2 hypersensitivity. Furthermore, catalase activity is increased during adaptation to sublethal H2O2 concentrations in YPD but not in buffer. We conclude that induction of cytosolic Ctt1 activity is vital in protecting yeast against exogenous H2O2 but this activity is inhibited by H2O2 when cells are challenged in nutrient-free media. PMID:24563848

  13. Catalase activity is stimulated by H(2)O(2) in rich culture medium and is required for H(2)O(2) resistance and adaptation in yeast.

    PubMed

    Martins, Dorival; English, Ann M

    2014-01-01

    Catalases are efficient scavengers of H2O2 and protect cells against H2O2 stress. Examination of the H2O2 stimulon in Saccharomyces cerevisiae revealed that the cytosolic catalase T (Ctt1) protein level increases 15-fold on H2O2 challenge in synthetic complete media although previous work revealed that deletion of the CCT1 or CTA1 genes (encoding peroxisomal/mitochondrial catalase A) does not increase the H2O2 sensitivity of yeast challenged in phosphate buffer (pH 7.4). This we attributed to our observation that catalase activity is depressed when yeast are challenged with H2O2 in nutrient-poor media. Hence, we performed a systematic comparison of catalase activity and cell viability of wild-type yeast and of the single catalase knockouts, ctt1∆ and cta1∆, following H2O2 challenge in nutrient-rich medium (YPD) and in phosphate buffer (pH 7.4). Ctt1 but not Cta1 activity is strongly induced by H2O2 when cells are challenged in YPD but suppressed when cells are challenged in buffer. Consistent with the activity results, exponentially growing ctt1∆ cells in YPD are more sensitive to H2O2 than wild-type or cta1∆ cells, whereas in buffer all three strains exhibit comparable H2O2 hypersensitivity. Furthermore, catalase activity is increased during adaptation to sublethal H2O2 concentrations in YPD but not in buffer. We conclude that induction of cytosolic Ctt1 activity is vital in protecting yeast against exogenous H2O2 but this activity is inhibited by H2O2 when cells are challenged in nutrient-free media. PMID:24563848

  14. Investigation of catalytic activity towards oxygen reduction reaction of Pt dispersed on boron doped graphene in acid medium.

    PubMed

    Pullamsetty, Ashok; Sundara, Ramaprabhu

    2016-10-01

    Boron doped graphene was prepared by a facile method and platinum (Pt) decoration over boron doped graphene was done in various chemical reduction methods such as sodium borohydride (NaBH4), polyol and modified polyol. X-ray diffraction analysis indicates that the synthesized catalyst particles are present in a nanocrystalline structure and transmission and scanning electron microscopy were employed to investigate the morphology and particle distribution. The electrochemical properties were investigated with the help of the rotating disk electrode (RDE) technique and cyclic voltammetry. The results show that the oxygen reduction reaction (ORR) takes place by a four-electron process. The kinetics of the ORR was evaluated using K-L and Tafel plots. The electrocatalyst obtained in modified polyol reduction method has shown the better catalytic activity compared to other two electrocatalysts. PMID:27393888

  15. Interaction of counterpropagating circularly polarized waves in an He--Ne ring laser with a gain greatly exceeding its losses

    SciTech Connect

    Mogil'naya, T.Y.; Savel'ev, I.I.; Timonin, P.V.; Yakushev, A.I.

    1983-10-01

    A theoretical and experimental investigation was made of the interaction between counterpropagating waves in an He--Ne ring laser having a circularly anisotropic resonator. This was done for large values of the ratio of the gain to the losses when the gain saturation was comparable with the gain itself. The dependences of the counterpropagating wave intensities and of the frequency of beats (formed when a longitudinal magnetic field was applied to the active medium) on the resonator detuning in a single-mode 0.63 ..mu.. wavelength laser were obtained experimentally. Numerically found theoretical dependences were in good agreement with experiment for values of the ratio of the gain to the losses of up to 2.9.

  16. FSH supplementation to culture medium is beneficial for activation and survival of preantral follicles enclosed in equine ovarian tissue.

    PubMed

    Aguiar, F L N; Lunardi, F O; Lima, L F; Rocha, R M P; Bruno, J B; Magalhães-Padilha, D M; Cibin, F W S; Nunes-Pinheiro, D C S; Gastal, M O; Rodrigues, A P R; Apgar, G A; Gastal, E L; Figueiredo, J R

    2016-04-01

    This study investigated the effect of adding different concentrations of bovine recombinant follicle-stimulating hormone on the IVC of equine preantral follicles enclosed in ovarian tissue fragments. Randomized ovarian fragments were fixed immediately (fresh noncultured control) or cultured for 1 or 7 days in α-MEM(+) supplemented with 0, 10, 50, and 100 ng/mL FSH and subsequently analyzed by classical histology. Culture media collected on Day 1 or Day 7 and were analyzed for steroids (estradiol and progesterone) and reactive oxygen species (ROS). After Day 1 and Day 7 of culture, 50-ng/mL FSH treatment had a greater (P < 0.05) percentage of morphologically normal follicles when compared to the other groups, except the 10-ng/mL FSH treatment at Day 1 of culture. The percentage of developing follicles (transition, primary, and secondary), and follicular and oocyte diameters were higher (P < 0.05) in the 50-ng/mL FSH treatment compared to the other groups after Day 7 of culture. Furthermore, estradiol secretion and ROS production were maintained (P > 0.05) throughout the culture in the 50-ng/mL FSH treatment. In conclusion, the addition of 50 ng/mL of FSH promoted activation of primordial follicles to developing follicles, improved survival of preantral follicles, and maintained estradiol and ROS production of equine ovarian tissue after 7 days of culture.

  17. Prismatic louver active façades for natural illumination and thermal energy gain in high-rise and commercial buildings

    NASA Astrophysics Data System (ADS)

    Vlachokostas, A.; Volkmann, C.; Madamopoulos, N.

    2013-06-01

    High-rise and commercial buildings in urban centers present a great challenge in terms of their energy consumption. Due to maximization of rentable square footage, the preferred urban façade system over the past 50 years has been the "curtain wall", only a few inches thick and comprised of modular steel or aluminum framing and predominant glass infills. The perceived Achilles heel of these modern glass façade systems is their thermal inefficiency: They are inadequate thermal barriers and exhibit excessive solar gain. The excessive solar gain has a negative impact on lighting and cooling loads of the entire building. This negative impact will be further exacerbated with rising energy costs. However, rather than view the glass façade's uncontrolled solar gain merely as a weakness contributing to higher energy consumption, the condition could indeed be considered as related to an energy solution. These glass façades can be retrofitted to operate as a provider of daylight and energy for the rest of the building, taking advantage of the overexposure to the sun. With today's technology, the sun's abundant renewable energy can be the driving force for the energy transition of these building envelopes. Illumination, thermal energy, and electricity production can be directly supplied from the sun, and when correctly and efficiently managed, they can lead to a significantly less energy-intensive building stock. We propose a multi-purpose, prismatic, louver-based façade to perform both daylight and thermal energy harvesting with a goal of offering a better daylight environment for the occupants, and reduce the energy consumption and carbon footprint of the building. While decentralized air-conditioning units are commonly accepted as façade "plug-ins", such decentralization could be utilized with more benefits by passively managing the interior space conditions, without using any extra power. Just as living organisms respond and adapt to the environmental changes in

  18. Response of methanotrophic activity and community structure to temperature changes in a diffusive CH/O counter gradient in an unsaturated porous medium.

    PubMed

    Urmann, Karina; Lazzaro, Anna; Gandolfi, Isabella; Schroth, Martin H; Zeyer, Josef

    2009-08-01

    Microbial methane oxidation is a key process in the global methane cycle. In the context of global warming, it is important to understand the responses of the methane-oxidizing microbial community to temperature changes in terms of community structure and activity. We studied microbial methane oxidation in a laboratory-column system in which a diffusive CH(4)/O(2) counter gradient was maintained in an unsaturated porous medium at temperatures between 4 and 20 degrees C. Methane oxidation was highly efficient at all temperatures, as on average 99 +/- 0.5% of methane supplied to the system was oxidized. The methanotrophic community that established in the model system after initial inoculation appeared to be able to adapt quickly to different temperatures, as methane emissions remained low even after the system was subjected to abrupt temperature changes. FISH showed that Type I as well as Type II methanotrophs were probably responsible for the observed activity in the column system, with a dominance of Type I methanotrophs. Cloning and sequencing suggested that Type I methanotrophs were represented by the genus Methylobacter while Type II were represented by Methylocystis. The results suggest that in an unsaturated system with diffusive substrate supply, direct effects of temperature on apparent methanotrophic activity and community may be of minor importance. However, this remains to be verified in the field.

  19. Oscillations and uniaxial mechanochemical waves in a model of an active poroelastic medium: Application to deformation patterns in protoplasmic droplets of Physarum polycephalum

    NASA Astrophysics Data System (ADS)

    Alonso, Sergio; Strachauer, Ulrike; Radszuweit, Markus; Bär, Markus; Hauser, Marcus J. B.

    2016-04-01

    Self-organization in cells often manifests itself in oscillations and waves. Here, we address deformation waves in protoplasmic droplets of the plasmodial slime mould Physarum polycephalum by modelling and experiments. In particular, we extend a one-dimensional model that considered the cell as a poroelastic medium, where active tension caused mechanochemical waves that were regulated by an inhibitor (Radszuweit et al., 2013). Our extension consists of a simple, qualitative chemical reaction-diffusion model (Brusselator) that describes the regulation of the inhibitor by another biochemical species. The biochemical reaction enhances the formation of mechanochemical waves if the reaction rates and input concentrations are near or inside an oscillatory regime. The period of the waves is found to be controlled by the characteristic oscillation period, whereas their wavelength is set by mechanical parameters. The model also allows for a systematic study of the chemical activity at the onset of mechanochemical waves. We also present examples for pattern formation in protoplasmic droplets of Physarum polycephalum including global oscillations where the central region of the droplets is in antiphase to the boundary zone, as well as travelling and standing wave-like uniaxial patterns. Finally, we apply our model to reproduce these experimental results by identifying the active tension inhibitor with the intracellular calcium concentration in the Physarum droplets and by using parameter values from mechanical experiments, respectively knowledge about the properties of calcium oscillations in Physarum. The simulation results are then found to be in good agreement with the experimental observations.

  20. Gain enhancement in a V-shaped plasmonic slot waveguide for efficient loss compensation at the subwavelength scale

    NASA Astrophysics Data System (ADS)

    Bian, Yusheng; Zheng, Zheng; Zhao, Xin; Yang, Pengfei; Liu, Lei; Zhu, Jinsong; Zhou, Tao

    2013-05-01

    An active plasmonic slot waveguide comprising an inverted triangular metal wedge incorporated inside a V-shaped plasmonic groove with a low-index gain medium embedded between them is presented, and its guiding properties are investigated numerically at the wavelength of 1550 nm. The presented waveguide is shown to be capable of supporting two fundamental plasmonic slot modes with high field localization to the V-shaped low-index slot region. Due to such strong optical confinement and significant field enhancement, the introduced gain in the slot could effectively compensate the propagation loss of the supported plasmonic modes. It is revealed that for the studied channel plasmonic slot and wedge plasmonic slot modes, notable gain enhancements are observable within a wide range of geometric parameters. For the considered structure with a 10-40 nm-wide slot, the enhancements of gain can be as large as 11%-159% for the CPS mode while 43%-174% for the WPS mode. These values could be further improved by adopting even narrower slots. It is shown that, by introducing a gain medium with coefficients around hundreds of cm-1, the modal loss can be largely or even fully compensated, with a subwavelength mode area achievable simultaneously. These unique features of the studied V-shaped plasmonic slot waveguide might be useful for its potential applications in compact, active plasmonic components.

  1. Analytic study of the chain dark decomposition reaction of iodides - atomic iodine donors - in the active medium of a pulsed chemical oxygen-iodine laser: 1. Criteria for the development of the branching chain dark decomposition reaction of iodides

    SciTech Connect

    Andreeva, Tamara L; Kuznetsova, S V; Maslov, Aleksandr I; Sorokin, Vadim N

    2009-02-28

    The scheme of chemical processes proceeding in the active medium of a pulsed chemical oxygen-iodine laser (COIL) is analysed. Based on the analysis performed, the complete system of differential equations corresponding to this scheme is replaced by a simplified system of equations describing in dimensionless variables the chain dark decomposition of iodides - atomic iodine donors, in the COIL active medium. The procedure solving this system is described, the basic parameters determining the development of the chain reaction are found and its specific time intervals are determined. The initial stage of the reaction is analysed and criteria for the development of the branching chain decomposition reaction of iodide in the COIL active medium are determined. (active media)

  2. Central Gain Control in Tinnitus and Hyperacusis

    PubMed Central

    Auerbach, Benjamin D.; Rodrigues, Paulo V.; Salvi, Richard J.

    2014-01-01

    Sensorineural hearing loss induced by noise or ototoxic drug exposure reduces the neural activity transmitted from the cochlea to the central auditory system. Despite a reduced cochlear output, neural activity from more central auditory structures is paradoxically enhanced at suprathreshold intensities. This compensatory increase in the central auditory activity in response to the loss of sensory input is referred to as central gain enhancement. Enhanced central gain is hypothesized to be a potential mechanism that gives rise to hyperacusis and tinnitus, two debilitating auditory perceptual disorders that afflict millions of individuals. This review will examine the evidence for gain enhancement in the central auditory system in response to cochlear damage. Further, it will address the potential cellular and molecular mechanisms underlying this enhancement and discuss the contribution of central gain enhancement to tinnitus and hyperacusis. Current evidence suggests that multiple mechanisms with distinct temporal and spectral profiles are likely to contribute to central gain enhancement. Dissecting the contributions of these different mechanisms at different levels of the central auditory system is essential for elucidating the role of central gain enhancement in tinnitus and hyperacusis and, most importantly, the development of novel treatments for these disorders. PMID:25386157

  3. The STAT3 HIES mutation is a gain-of-function mutation that activates genes via AGG-element carrying promoters

    PubMed Central

    Xu, Li; Ji, Jin-Jun; Le, Wangping; Xu, Yan S.; Dou, Dandan; Pan, Jieli; Jiao, Yifeng; Zhong, Tianfei; Wu, Dehong; Wang, Yumei; Wen, Chengping; Xie, Guan-Qun; Yao, Feng; Zhao, Heng; Fan, Yong-Sheng; Chin, Y. Eugene

    2015-01-01

    Cytokine or growth factor activated STAT3 undergoes multiple post-translational modifications, dimerization and translocation into nuclei, where it binds to serum-inducible element (SIE, ‘TTC(N3)GAA’)-bearing promoters to activate transcription. The STAT3 DNA binding domain (DBD, 320–494) mutation in hyper immunoglobulin E syndrome (HIES), called the HIES mutation (R382Q, R382W or V463Δ), which elevates IgE synthesis, inhibits SIE binding activity and sensitizes genes such as TNF-α for expression. However, the mechanism by which the HIES mutation sensitizes STAT3 in gene induction remains elusive. Here, we report that STAT3 binds directly to the AGG-element with the consensus sequence ‘AGG(N3)AGG’. Surprisingly, the helical N-terminal region (1–355), rather than the canonical STAT3 DBD, is responsible for AGG-element binding. The HIES mutation markedly enhances STAT3 AGG-element binding and AGG-promoter activation activity. Thus, STAT3 is a dual specificity transcription factor that promotes gene expression not only via SIE- but also AGG-promoter activity. PMID:26384563

  4. Opposite Effects of mGluR1a and mGluR5 Activation on Nucleus Accumbens Medium Spiny Neuron Dendritic Spine Density.

    PubMed

    Gross, Kellie S; Brandner, Dieter D; Martinez, Luis A; Olive, M Foster; Meisel, Robert L; Mermelstein, Paul G

    2016-01-01

    The group I metabotropic glutamate receptors (mGluR1a and mGluR5) are important modulators of neuronal structure and function. Although these receptors share common signaling pathways, they are capable of having distinct effects on cellular plasticity. We investigated the individual effects of mGluR1a or mGluR5 activation on dendritic spine density in medium spiny neurons in the nucleus accumbens (NAc), which has become relevant with the potential use of group I mGluR based therapeutics in the treatment of drug addiction. We found that systemic administration of mGluR subtype-specific positive allosteric modulators had opposite effects on dendritic spine densities. Specifically, mGluR5 positive modulation decreased dendritic spine densities in the NAc shell and core, but was without effect in the dorsal striatum, whereas increased spine densities in the NAc were observed with mGluR1a positive modulation. Additionally, direct activation of mGluR5 via CHPG administration into the NAc also decreased the density of dendritic spines. These data provide insight on the ability of group I mGluRs to induce structural plasticity in the NAc and demonstrate that the group I mGluRs are capable of producing not just distinct, but opposing, effects on dendritic spine density. PMID:27618534

  5. Selective expression of a dominant-negative type Iα PKA regulatory subunit in striatal medium spiny neurons impairs gene expression and leads to reduced feeding and locomotor activity.

    PubMed

    Yang, Linghai; Gilbert, Merle L; Zheng, Ruimao; McKnight, G Stanley

    2014-04-01

    Striatal medium spiny neurons (MSNs) mediate many of the physiological effects of dopamine, including the regulation of feeding and motor behaviors. Dopaminergic inputs from the midbrain modulate MSN excitability through pathways that involve cAMP and protein kinase A (PKA), but the physiological role of specific PKA isoforms in MSN neurons remains poorly understood. One of the major PKA regulatory (R) subunit isoforms expressed in MSNs is RIIβ, which localizes the PKA holoenzyme primarily to dendrites by interaction with AKAP5 and other scaffolding proteins. However, RI (RIα and RIβ) subunits are also expressed in MSNs and the RI holoenzyme has a weaker affinity for most scaffolding proteins and tends to localize in the cell body. We generated mice with selective expression of a dominant-negative RI subunit (RIαB) in striatal MSNs and show that this dominant-negative RIαB localizes to the cytoplasm and specifically inhibits type I PKA activity in the striatum. These mice are normal at birth; however, soon after weaning they exhibit growth retardation and the adult mice are hypophagic, lean, and resistant to high-fat diet-induced hyperphagia and obesity. The RIαB-expressing mice also exhibit decreased locomotor activity and decreased dopamine-regulated CREB phosphorylation and c-fos gene expression in the striatum. Our results demonstrate a critical role for cytoplasmic RI-PKA holoenzyme in gene regulation and the overall physiological function of MSNs. PMID:24695708

  6. Opposite Effects of mGluR1a and mGluR5 Activation on Nucleus Accumbens Medium Spiny Neuron Dendritic Spine Density

    PubMed Central

    Gross, Kellie S.; Brandner, Dieter D.; Martinez, Luis A.; Olive, M. Foster; Meisel, Robert L.

    2016-01-01

    The group I metabotropic glutamate receptors (mGluR1a and mGluR5) are important modulators of neuronal structure and function. Although these receptors share common signaling pathways, they are capable of having distinct effects on cellular plasticity. We investigated the individual effects of mGluR1a or mGluR5 activation on dendritic spine density in medium spiny neurons in the nucleus accumbens (NAc), which has become relevant with the potential use of group I mGluR based therapeutics in the treatment of drug addiction. We found that systemic administration of mGluR subtype-specific positive allosteric modulators had opposite effects on dendritic spine densities. Specifically, mGluR5 positive modulation decreased dendritic spine densities in the NAc shell and core, but was without effect in the dorsal striatum, whereas increased spine densities in the NAc were observed with mGluR1a positive modulation. Additionally, direct activation of mGluR5 via CHPG administration into the NAc also decreased the density of dendritic spines. These data provide insight on the ability of group I mGluRs to induce structural plasticity in the NAc and demonstrate that the group I mGluRs are capable of producing not just distinct, but opposing, effects on dendritic spine density. PMID:27618534

  7. Managing price, gaining profit.

    PubMed

    Marn, M V; Rosiello, R L

    1992-01-01

    The fastest and most effective way for a company to realize maximum profit is to get its pricing right. The right price can boost profit faster than increasing volume will; the wrong price can shrink it just as quickly. Yet many otherwise tough-minded managers miss out on significant profits because they shy away from pricing decisions for fear that they will alienate their customers. Worse, if management isn't controlling its pricing policies, there's a good chance that the company's clients are manipulating them to their own advantage. McKinsey & Company's Michael Marn and Robert Rosiello show managers how to gain control of the pricing puzzle and capture untapped profit potential by using two basic concepts: the pocket price waterfall and the pocket price band. The pocket price waterfall reveals how price erodes between a company's invoice figure and the actual amount paid by the customer--the transaction price. It tracks the volume purchase discounts, early payment bonuses, and frequent customer incentives that squeeze a company's profits. The pocket price band plots the range of pocket prices over which any given unit volume of a single product sells. Wide price bands are commonplace: some manufacturers' transaction prices for a given product range 60%; one fastener supplier's price band ranged up to 500%. Managers who study their pocket price waterfalls and bands can identify unnecessary discounting at the transaction level, low-performance accounts, and misplaced marketing efforts. The problems, once identified, are typically easy and inexpensive to remedy. PMID:10121318

  8. Managing price, gaining profit.

    PubMed

    Marn, M V; Rosiello, R L

    1992-01-01

    The fastest and most effective way for a company to realize maximum profit is to get its pricing right. The right price can boost profit faster than increasing volume will; the wrong price can shrink it just as quickly. Yet many otherwise tough-minded managers miss out on significant profits because they shy away from pricing decisions for fear that they will alienate their customers. Worse, if management isn't controlling its pricing policies, there's a good chance that the company's clients are manipulating them to their own advantage. McKinsey & Company's Michael Marn and Robert Rosiello show managers how to gain control of the pricing puzzle and capture untapped profit potential by using two basic concepts: the pocket price waterfall and the pocket price band. The pocket price waterfall reveals how price erodes between a company's invoice figure and the actual amount paid by the customer--the transaction price. It tracks the volume purchase discounts, early payment bonuses, and frequent customer incentives that squeeze a company's profits. The pocket price band plots the range of pocket prices over which any given unit volume of a single product sells. Wide price bands are commonplace: some manufacturers' transaction prices for a given product range 60%; one fastener supplier's price band ranged up to 500%. Managers who study their pocket price waterfalls and bands can identify unnecessary discounting at the transaction level, low-performance accounts, and misplaced marketing efforts. The problems, once identified, are typically easy and inexpensive to remedy.

  9. Raman mode random lasing in ZnS-β-carotene random gain media

    NASA Astrophysics Data System (ADS)

    Bingi, Jayachandra; Warrier, Anita R.; Vijayan, C.

    2013-06-01

    Raman mode random lasing is demonstrated in ZnS-β-carotene random gain media at room temperature. A self assembled random medium is prepared with ZnS sub micron spheres synthesized by homogeneous precipitation method. β-Carotene extracted from pale green leaves is embedded in this random medium. The emission band of ZnS random medium (on excitation at 488 nm) overlaps considerably with that of β-carotene, which functions as a gain medium. Here, random medium works as a cavity, leading to Raman mode lasing at 517 nm and 527 nm triggered by stimulated resonance Raman scattering.

  10. Teacher-and Child-Managed Academic Activities in Preschool and Kindergarten and Their Influence on Children's Gains in Emergent Academic Skills

    ERIC Educational Resources Information Center

    de Haan, Annika K. E.; Elbers, Ed; Leseman, Paul P. M.

    2014-01-01

    The aim of this study was to assess whether children's development benefited from teacher-and child-managed academic activities in the preschool and kindergarten classroom. Extensive systematic observations during four half-days in preschool ("n"?=?8) and kindergarten ("n"?=?8) classrooms revealed that classrooms differed…

  11. On Comparing Transition Rate Gains.

    ERIC Educational Resources Information Center

    Reuterberg, Sven-Eric

    This report is about the problem of making transition or enrollment rate gains comparable. It is shown that measures based on the proportions themselves, i.e. the difference between proportions, the proportion ratio and the residual gain ratio do not make the gains comparable. Instead a non-linear transformation has to be done. Two such…

  12. Red, green, and blue lasing enabled by single-exciton gain in colloidal quantum dot films

    DOEpatents

    Nurmikko, Arto V.; Dang, Cuong

    2016-06-21

    The methods and materials described herein contemplate the use films of colloidal quantum dots as a gain medium in a vertical-cavity surface-emitting laser. The present disclosure demonstrates a laser with single-exciton gain in the red, green, and blue wavelengths. Leveraging this nanocomposite gain, the results realize a significant step toward full-color single-material lasers.

  13. Should I Gain Weight?

    MedlinePlus

    ... of moderate to vigorous physical activity every day. Strength training , when done safely, is a healthy way to ... you've hit puberty, the right amount of strength training will help your muscles become stronger and have ...

  14. Unidirectional high gain brake stop

    NASA Technical Reports Server (NTRS)

    Lang, David J. (Inventor)

    1987-01-01

    This invention relates to a unidirectional high gain brake arrangement that includes in combination a shaft mounted for rotation within a housing. The shaft is rotatable in either direction. A brake is selectively releasably coupled to the housing and to the shaft. The brake has a first member. An intermittent motion device is respectively coupled through the first member to the housing and through a one-way clutch to the shaft. The brake also has a second member that is mechanically coupled to the first brake member and to the housing. The intermittent motion device causes the brake to be activated by movement imparted to the first brake member after a preset number of revolutions of the shaft in one direction. The brake is released by rotation of the shaft in an opposite direction whereby torque transmitted through the one-way clutch to the first brake member is removed.

  15. Adolescent drug addiction treatment and weight gain.

    PubMed

    Hodgkins, Candace C; Cahill, Kevin S; Seraphine, Anne E; Frost-Pineda, Kimberly; Gold, Mark S

    2004-01-01

    Neurotransmitter release in the nucleus accumbens use has been linked to self-administration and learning following drug use. This endogenous reward system is also activated following food intake or sex. Therefore, rebound hyperphagia following abstinence may be a mechanism to replenish the release of neurotransmitters in this reward system, leading to increased weight gain and a rise in body mass index during recovery from substance abuse. In this report, we examined the relationship between supervised drug abstinence and increased weight gain among adolescents at a residential substance abuse treatment center. Mean weight change over time was followed by repeated analysis of weight and body mass index. Significant weight gain and body mass index increase was observed during supervised and confirmed abstinence from drug use. Furthermore, significant interactions between tobacco use and primary substance use disorder with weight gain was demonstrated by multivariate analysis of variance.

  16. Airflow models gaining clout

    SciTech Connect

    Post, N.M.

    1994-10-10

    Move over, mock-ups. So long, smoke bombs. Take a walk, wind tunnels. Computational fluid dynamics, a spaceage simulation technique, is gaining velocity in the building community. And the design of inner spaces may never be the same. CFD is an equation-intensive computer modeling method that can simulate transient and steady-state airflow patterns and temperature gradients, indoors or out. CFD is used to downsize heating, ventilating and air conditioning systems, locate air outlets, and in general, create spaces that offer creature comfort, provide quality air and use less energy. The method is good for new construction, retrofits and forensic work, for example to investigate a building fire or a contaminant. In a room, CFD helps engineers consider, over a period of time, the combined impacts of ventilation, size, shape, contents, weather, even fenestration. For its first decade or two, CFD stayed the near-exclusive domain of aerospace, defense and electronics. With few exceptions, the building community could not afford the supercomputers that were needed to run the tens of thousands of equations involved. However, in the past few years, thanks to the increasing power and decreasing cost of computers, CFD simulation became practical. Curtain wall designers are even using it, though not without some controversy. Indoor air quality specialists, smoke and fire-spread researchers, laboratory designers, energy engineers, code writers, architects, and plant and building engineers are uncharacteristically upbeat about the tool. {open_quotes}CFD modeling is so many light years ahead of design tools that exist,{close_quotes} says Mariano Rodriguez, director of research and development for architect The Hillier Group, Princeton, N.J. {open_quotes}It`s the next step up from a wind tunnel test, and you don`t need a $300,000 wind tunnel.{close_quotes}

  17. Effects of active region design on gain and carrier injection and transport of CW (20\\bar{2}\\bar{1}) semipolar InGaN laser diodes

    NASA Astrophysics Data System (ADS)

    Becerra, Daniel L.; Cohen, Daniel A.; Farrell, Robert M.; DenBaars, Steven P.; Nakamura, Shuji

    2016-09-01

    High-power CW semipolar (20\\bar{2}\\bar{1}) laser diodes (LDs) were studied. Improved efficiencies (threshold, differential, and wall plug) were observed when the number of quantum wells (QWs) in the active region was reduced from 4 to 2. Threshold current densities as low as 2.6 kA/cm2 were obtained. The differential efficiency of a 5 µm wide by 1200 µm long LD with a 2-QW active region was 54% and the wall plug efficiency was 11%. Experimental and analytical analyses of the devices suggested carrier leakage from an ineffective electron-blocking layer, providing an explanation for the high voltage observed in all the devices.

  18. Cutaneous activation of the inhibitory L30 interneurons provides a mechanism for regulating adaptive gain control in the siphon withdrawal reflex of Aplysia.

    PubMed

    Fischer, T M; Carew, T J

    1995-01-01

    The functional role of inhibition in the neural network underlying the siphon withdrawal response (SWR) of Aplysia was assessed by examining a recurrent circuit comprised of identified inhibitory interneurons (L30s), and excitatory interneurons (L29s). We previously showed that activity-dependent potentiation of the L30 inhibitory synapse onto L29 can regulate the net excitatory input elicited by tactile siphon stimulation onto siphon motor neurons (LFS cells) (Fischer and Carew, 1993a). To explore the functional significance of L30 potentiated inhibition, we have examined how a behaviorally relevant stimulus that activates the L30 interneurons modulates the SWR circuit. Utilizing a reduced preparation, we show that weak tactile stimulation of the tail strongly activates the L30s, and leads to significant potentiation of the L30 synapse. Next, we demonstrate that similar weak tail stimulation produces significant inhibition of siphon tap-evoked responses in both L29 interneurons and LFS motor neurons. We further show that this form of inhibition is transient, having a time course of approximately 60 sec. Finally, we directly tested the role of the L30s in mediating this form of inhibition by hyperpolarizing two (of three) L30 interneurons during tail stimulation. L30 inactivation significantly attenuated tail stimulation-induced inhibition of siphon-evoked input to both L29 interneurons and LFS motor neurons. Based on these results, we suggest that L30-potentiated inhibition may have an important adaptive role in optimizing the signal-to-noise ratio for activation of the SWR circuit by providing stabilization of SWR responsiveness under a wide range of environmental conditions.

  19. Identification of candidate agents active against N. ceranae infection in honey bees: establishment of a medium throughput screening assay based on N. ceranae infected cultured cells.

    PubMed

    Gisder, Sebastian; Genersch, Elke

    2015-01-01

    Many flowering plants in both natural ecosytems and agriculture are dependent on insect pollination for fruit set and seed production. Managed honey bees (Apis mellifera) and wild bees are key pollinators providing this indispensable eco- and agrosystem service. Like all other organisms, bees are attacked by numerous pathogens and parasites. Nosema apis is a honey bee pathogenic microsporidium which is widely distributed in honey bee populations without causing much harm. Its congener Nosema ceranae was originally described as pathogen of the Eastern honey bee (Apis cerana) but jumped host from A. cerana to A. mellifera about 20 years ago and spilled over from A. mellifera to Bombus spp. quite recently. N. ceranae is now considered a deadly emerging parasite of both Western honey bees and bumblebees. Hence, novel and sustainable treatment strategies against N. ceranae are urgently needed to protect honey and wild bees. We here present the development of an in vitro medium throughput screening assay for the identification of candidate agents active against N. ceranae infections. This novel assay is based on our recently developed cell culture model for N. ceranae and coupled with an RT-PCR-ELISA protocol for quantification of N. ceranae in infected cells. The assay has been adapted to the 96-well microplate format to allow automated analysis. Several substances with known (fumagillin) or presumed (surfactin) or no (paromomycin) activity against N. ceranae were tested as well as substances for which no data concerning N. ceranae inhibition existed. While fumagillin and two nitroimidazoles (metronidazole, tinidazole) totally inhibited N. ceranae proliferation, all other test substances were inactive. In summary, the assay proved suitable for substance screening and demonstrated the activity of two synthetic antibiotics against N. ceranae.

  20. Identification of candidate agents active against N. ceranae infection in honey bees: establishment of a medium throughput screening assay based on N. ceranae infected cultured cells.

    PubMed

    Gisder, Sebastian; Genersch, Elke

    2015-01-01

    Many flowering plants in both natural ecosytems and agriculture are dependent on insect pollination for fruit set and seed production. Managed honey bees (Apis mellifera) and wild bees are key pollinators providing this indispensable eco- and agrosystem service. Like all other organisms, bees are attacked by numerous pathogens and parasites. Nosema apis is a honey bee pathogenic microsporidium which is widely distributed in honey bee populations without causing much harm. Its congener Nosema ceranae was originally described as pathogen of the Eastern honey bee (Apis cerana) but jumped host from A. cerana to A. mellifera about 20 years ago and spilled over from A. mellifera to Bombus spp. quite recently. N. ceranae is now considered a deadly emerging parasite of both Western honey bees and bumblebees. Hence, novel and sustainable treatment strategies against N. ceranae are urgently needed to protect honey and wild bees. We here present the development of an in vitro medium throughput screening assay for the identification of candidate agents active against N. ceranae infections. This novel assay is based on our recently developed cell culture model for N. ceranae and coupled with an RT-PCR-ELISA protocol for quantification of N. ceranae in infected cells. The assay has been adapted to the 96-well microplate format to allow automated analysis. Several substances with known (fumagillin) or presumed (surfactin) or no (paromomycin) activity against N. ceranae were tested as well as substances for which no data concerning N. ceranae inhibition existed. While fumagillin and two nitroimidazoles (metronidazole, tinidazole) totally inhibited N. ceranae proliferation, all other test substances were inactive. In summary, the assay proved suitable for substance screening and demonstrated the activity of two synthetic antibiotics against N. ceranae. PMID:25658121

  1. Identification of Candidate Agents Active against N. ceranae Infection in Honey Bees: Establishment of a Medium Throughput Screening Assay Based on N. ceranae Infected Cultured Cells

    PubMed Central

    Gisder, Sebastian; Genersch, Elke

    2015-01-01

    Many flowering plants in both natural ecosytems and agriculture are dependent on insect pollination for fruit set and seed production. Managed honey bees (Apis mellifera) and wild bees are key pollinators providing this indispensable eco- and agrosystem service. Like all other organisms, bees are attacked by numerous pathogens and parasites. Nosema apis is a honey bee pathogenic microsporidium which is widely distributed in honey bee populations without causing much harm. Its congener Nosema ceranae was originally described as pathogen of the Eastern honey bee (Apis cerana) but jumped host from A. cerana to A. mellifera about 20 years ago and spilled over from A. mellifera to Bombus spp. quite recently. N. ceranae is now considered a deadly emerging parasite of both Western honey bees and bumblebees. Hence, novel and sustainable treatment strategies against N. ceranae are urgently needed to protect honey and wild bees. We here present the development of an in vitro medium throughput screening assay for the identification of candidate agents active against N. ceranae infections. This novel assay is based on our recently developed cell culture model for N. ceranae and coupled with an RT-PCR-ELISA protocol for quantification of N. ceranae in infected cells. The assay has been adapted to the 96-well microplate format to allow automated analysis. Several substances with known (fumagillin) or presumed (surfactin) or no (paromomycin) activity against N. ceranae were tested as well as substances for which no data concerning N. ceranae inhibition existed. While fumagillin and two nitroimidazoles (metronidazole, tinidazole) totally inhibited N. ceranae proliferation, all other test substances were inactive. In summary, the assay proved suitable for substance screening and demonstrated the activity of two synthetic antibiotics against N. ceranae. PMID:25658121

  2. Synergistic Activation of Dopamine D1 and TrkB Receptors Mediate Gain Control of Synaptic Plasticity in the Basolateral Amygdala

    PubMed Central

    Li, Chenchen; Dabrowska, Joanna; Hazra, Rimi; Rainnie, Donald G.

    2011-01-01

    Fear memory formation is thought to require dopamine, brain-derived neurotrophic factor (BDNF) and zinc release in the basolateral amygdala (BLA), as well as the induction of long term potentiation (LTP) in BLA principal neurons. However, no study to date has shown any relationship between these processes in the BLA. Here, we have used in vitro whole-cell patch clamp recording from BLA principal neurons to investigate how dopamine, BDNF, and zinc release may interact to modulate the LTP induction in the BLA. LTP was induced by either theta burst stimulation (TBS) protocol or spaced 5 times high frequency stimulation (5xHFS). Significantly, both TBS and 5xHFS induced LTP was fully blocked by the dopamine D1 receptor antagonist, SCH23390. LTP induction was also blocked by the BDNF scavenger, TrkB-FC, the zinc chelator, DETC, as well as by an inhibitor of matrix metalloproteinases (MMPs), gallardin. Conversely, prior application of the dopamine reuptake inhibitor, GBR12783, or the D1 receptor agonist, SKF39393, induced robust and stable LTP in response to a sub-threshold HFS protocol (2xHFS), which does not normally induce LTP. Similarly, prior activation of TrkB receptors with either a TrkB receptor agonist, or BDNF, also reduced the threshold for LTP-induction, an effect that was blocked by the MEK inhibitor, but not by zinc chelation. Intriguingly, the TrkB receptor agonist-induced reduction of LTP threshold was fully blocked by prior application of SCH23390, and the reduction of LTP threshold induced by GBR12783 was blocked by prior application of TrkB-FC. Together, our results suggest a cellular mechanism whereby the threshold for LTP induction in BLA principal neurons is critically dependent on the level of dopamine in the extracellular milieu and the synergistic activation of postsynaptic D1 and TrkB receptors. Moreover, activation of TrkB receptors appears to be dependent on concurrent release of zinc and activation of MMPs. PMID:22022509

  3. Reducing gain shifts in photomultiplier tubes

    DOEpatents

    Cohn, Charles E.

    1976-01-01

    A means is provided for reducing gain shifts in multiplier tubes due to varying event count rates. It includes means for limiting the number of cascaded, active dynodes of the multiplier tube to a predetermined number with the last of predetermined number of dynodes being the output terminal of the tube. This output is applied to an amplifier to make up for the gain sacrificed by not totally utilizing all available active stages of the tube. Further reduction is obtained by illuminating the predetermined number of dynodes with a light source of such intensity that noise appearing at the output dynode associated with the illumination is negligible.

  4. Private Gain, Public Loss.

    ERIC Educational Resources Information Center

    Lapp, David, Ed.; Ruben, Barbara, Ed.

    1994-01-01

    Corporations contribute curricular materials to schools. Argues that the goal of these materials is to initiate the school-age population to their products, enhance their public image, and increase visibility of their products. Cites examples of corporate activity with these goals. (MDH)

  5. Electrocatalytic oxidation of ethanol in acid medium: Enhancement of activity of vulcan-supported Platinum-based nanoparticles upon immobilization within nanostructured zirconia matrices

    NASA Astrophysics Data System (ADS)

    Rutkowska, Iwona A.; Kulesza, Pawel J.

    2014-09-01

    Composite electrocatalytic materials that utilize carbon (Vulcan) supported Pt or PtRu nanoparticles dispersed within thin films of zirconia (ZrO2) are considered here for oxidation of such a biofuel as ethanol in acid medium. The systems were characterized using electrochemical techniques as well as transmission electron microscopy. The enhancement of activity was clearly evident upon comparison of the respective voltammetric and chronoamperometric current densities recorded (at room temperature in 0.5 mol dm-3H2SO4 containing 0.5 mol dm-3 ethanol) using the Vulcan supported Pt and PtRu catalysts in the presence and absence of zirconia. In all cases, the noble metal loading was the same, 100 μg cm-2. Apparently, the existence of large population of hydroxyl groups (originating from zirconia) in the vicinity of Pt-based catalyst, in addition to possible specific interactions between zirconia and the ruthenium component of PtRu, facilitated the oxidative removal (from Pt) of the passivating (e.g., CO) reaction intermediates (adsorbates). By utilizing carbon supported, rather than bare or unsupported, Pt or PtRu nanoparticles (dispersed within the semiconducting zirconia), the overall charge distribution at the electrocatalytic interface was improved.

  6. Glycolytic enzyme activity is essential for domestic cat (Felis catus) and cheetah (Acinonyx jubatus) sperm motility and viability in a sugar-free medium.

    PubMed

    Terrell, Kimberly A; Wildt, David E; Anthony, Nicola M; Bavister, Barry D; Leibo, S P; Penfold, Linda M; Marker, Laurie L; Crosier, Adrienne E

    2011-06-01

    We have previously reported a lack of glucose uptake in domestic cat and cheetah spermatozoa, despite observing that these cells produce lactate at rates that correlate positively with sperm function. To elucidate the role of glycolysis in felid sperm energy production, we conducted a comparative study in the domestic cat and cheetah, with the hypothesis that sperm motility and viability are maintained in both species in the absence of glycolytic metabolism and are fueled by endogenous substrates. Washed ejaculates were incubated in chemically defined medium in the presence/absence of glucose and pyruvate. A second set of ejaculates was exposed to a chemical inhibitor of either lactate dehydrogenase (sodium oxamate) or glyceraldehyde-3-phosphate dehydrogenase (alpha-chlorohydrin). Sperm function (motility and acrosomal integrity) and lactate production were assessed, and a subset of spermatozoa was assayed for intracellular glycogen. In both the cat and cheetah, sperm function was maintained without exogenous substrates and following lactate dehydrogenase inhibition. Lactate production occurred in the absence of exogenous hexoses, but only if pyruvate was present. Intracellular glycogen was not detected in spermatozoa from either species. Unexpectedly, glycolytic inhibition by alpha-chlorohydrin resulted in an immediate decline in sperm motility, particularly in the domestic cat. Collectively, our findings reveal an essential role of the glycolytic pathway in felid spermatozoa that is unrelated to hexose metabolism or lactate formation. Instead, glycolytic enzyme activity could be required for the metabolism of endogenous lipid-derived glycerol, with fatty acid oxidation providing the primary energy source in felid spermatozoa.

  7. Segregation and Crosstalk of D1 Receptor-Mediated Activation of ERK in Striatal Medium Spiny Neurons upon Acute Administration of Psychostimulants

    PubMed Central

    Gutierrez-Arenas, Omar; Eriksson, Olivia; Hellgren Kotaleski, Jeanette

    2014-01-01

    The convergence of corticostriatal glutamate and dopamine from the midbrain in the striatal medium spiny neurons (MSN) triggers synaptic plasticity that underlies reinforcement learning and pathological conditions such as psychostimulant addiction. The increase in striatal dopamine produced by the acute administration of psychostimulants has been found to activate not only effectors of the AC5/cAMP/PKA signaling cascade such as GluR1, but also effectors of the NMDAR/Ca2+/RAS cascade such as ERK. The dopamine-triggered effects on both these cascades are mediated by D1R coupled to Golf but while the phosphorylation of GluR1 is affected by reductions in the available amount of Golf but not of D1R, the activation of ERK follows the opposite pattern. This segregation is puzzling considering that D1R-induced Golf activation monotonically increases with DA and that there is crosstalk from the AC5/cAMP/PKA cascade to the NMDAR/Ca2+/RAS cascade via a STEP (a tyrosine phosphatase). In this work, we developed a signaling model which accounts for this segregation based on the assumption that a common pool of D1R and Golf is distributed in two D1R/Golf signaling compartments. This model integrates a relatively large amount of experimental data for neurons in vivo and in vitro. We used it to explore the crosstalk topologies under which the sensitivities of the AC5/cAMP/PKA signaling cascade to reductions in D1R or Golf are transferred or not to the activation of ERK. We found that the sequestration of STEP by its substrate ERK together with the insensitivity of STEP activity on targets upstream of ERK (i.e. Fyn and NR2B) to PKA phosphorylation are able to explain the experimentally observed segregation. This model provides a quantitative framework for simulation based experiments to study signaling required for long term potentiation in MSNs. PMID:24499932

  8. Segregation and crosstalk of D1 receptor-mediated activation of ERK in striatal medium spiny neurons upon acute administration of psychostimulants.

    PubMed

    Gutierrez-Arenas, Omar; Eriksson, Olivia; Kotaleski, Jeanette Hellgren

    2014-01-01

    The convergence of corticostriatal glutamate and dopamine from the midbrain in the striatal medium spiny neurons (MSN) triggers synaptic plasticity that underlies reinforcement learning and pathological conditions such as psychostimulant addiction. The increase in striatal dopamine produced by the acute administration of psychostimulants has been found to activate not only effectors of the AC5/cAMP/PKA signaling cascade such as GluR1, but also effectors of the NMDAR/Ca(2+)/RAS cascade such as ERK. The dopamine-triggered effects on both these cascades are mediated by D1R coupled to Golf but while the phosphorylation of GluR1 is affected by reductions in the available amount of Golf but not of D1R, the activation of ERK follows the opposite pattern. This segregation is puzzling considering that D1R-induced Golf activation monotonically increases with DA and that there is crosstalk from the AC5/cAMP/PKA cascade to the NMDAR/Ca(2+)/RAS cascade via a STEP (a tyrosine phosphatase). In this work, we developed a signaling model which accounts for this segregation based on the assumption that a common pool of D1R and Golf is distributed in two D1R/Golf signaling compartments. This model integrates a relatively large amount of experimental data for neurons in vivo and in vitro. We used it to explore the crosstalk topologies under which the sensitivities of the AC5/cAMP/PKA signaling cascade to reductions in D1R or Golf are transferred or not to the activation of ERK. We found that the sequestration of STEP by its substrate ERK together with the insensitivity of STEP activity on targets upstream of ERK (i.e. Fyn and NR2B) to PKA phosphorylation are able to explain the experimentally observed segregation. This model provides a quantitative framework for simulation based experiments to study signaling required for long term potentiation in MSNs. PMID:24499932

  9. Symmetry breaking and multipeaked solitons in inhomogeneous gain landscapes

    SciTech Connect

    Kartashov, Yaroslav V.; Vysloukh, Victor A.; Konotop, Vladimir V.

    2011-04-15

    We address one-dimensional soliton formation in a cubic nonlinear medium with two-photon absorption and transversally inhomogeneous gain landscape consisting of a single or several amplifying channels. Existence of the solitons requires certain threshold gain while the properties of solitons strongly depend on whether the number of the amplifying channels is odd or even. In the former case, an increase of the gain leads to symmetry breaking, which occurs through the pitchfork bifurcation, and to emergence of a single or several coexisting stable asymmetric modes. In the case of an even number of amplifying channels, we have found only asymmetric stable states.

  10. Temperature responses of the Rubisco maximum carboxylase activity across domains of life: phylogenetic signals, trade-offs, and importance for carbon gain.

    PubMed

    Galmés, J; Kapralov, M V; Copolovici, L O; Hermida-Carrera, C; Niinemets, Ü

    2015-02-01

    Temperature response of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) catalytic properties directly determines the CO2 assimilation capacity of photosynthetic organisms as well as their survival in environments with different thermal conditions. Despite unquestionable importance of Rubisco, the comprehensive analysis summarizing temperature responses of Rubisco traits across lineages of carbon-fixing organisms is lacking. Here, we present a review of the temperature responses of Rubisco carboxylase specific activity (c(cat)(c)) within and across domains of life. In particular, we consider the variability of temperature responses, and their ecological, physiological, and evolutionary controls. We observed over two-fold differences in the energy of activation (ΔH(a)) among different groups of photosynthetic organisms, and found significant differences between C3 plants from cool habitats, C3 plants from warm habitats and C4 plants. According to phylogenetically independent contrast analysis, ΔH(a) was not related to the species optimum growth temperature (T growth), but was positively correlated with Rubisco specificity factor (S(c/o)) across all organisms. However, when only land plants were analyzed, ΔH(a) was positively correlated with both T(growth) and S(c/o), indicating different trends for these traits in plants versus unicellular aquatic organisms, such as algae and bacteria. The optimum temperature (T(opt)) for k(cat)(c) correlated with S(c/o) for land plants and for all organisms pooled, but the effect of T growth on T(opt) was driven by species phylogeny. The overall phylogenetic signal was significant for all analyzed parameters, stressing the importance of considering the evolutionary framework and accounting for shared ancestry when deciphering relationships between Rubisco kinetic parameters. We argue that these findings have important implications for improving global photosynthesis models.

  11. Fast gain and phase recovery of semiconductor optical amplifiers based on submonolayer quantum dots

    SciTech Connect

    Herzog, Bastian Owschimikow, Nina; Kaptan, Yücel; Kolarczik, Mirco; Switaiski, Thomas; Woggon, Ulrike; Schulze, Jan-Hindrik; Rosales, Ricardo; Strittmatter, André; Bimberg, Dieter; Pohl, Udo W.

    2015-11-16

    Submonolayer quantum dots as active medium in opto-electronic devices promise to combine the high density of states of quantum wells with the fast recovery dynamics of self-assembled quantum dots. We investigate the gain and phase recovery dynamics of a semiconductor optical amplifier based on InAs submonolayer quantum dots in the regime of linear operation by one- and two-color heterodyne pump-probe spectroscopy. We find an as fast recovery dynamics as for quantum dot-in-a-well structures, reaching 2 ps at moderate injection currents. The effective quantum well embedding the submonolayer quantum dots acts as a fast and efficient carrier reservoir.

  12. Gain compression effect on the modulation dynamics of an optically injection-locked semiconductor laser using gain lever

    NASA Astrophysics Data System (ADS)

    Sarraute, J.-M.; Schires, K.; LaRochelle, S.; Grillot, F.

    2016-03-01

    The modulation response of an optically-injected gain lever semiconductor laser is studied and calculations show that a gain-lever laser operating under medium to strong optical injection provides a unique and robust configuration for ultra large bandwidth enhancement. Modulation bandwidths above nine times the relaxation oscillation frequency of the free-running laser can be reached using injection-locking conditions that are reasonable for practical applications. The impact of the gain compression on the modulation dynamic is discussed for the first time. This work is of prime importance for the development of directly-modulated broadband optical sources for high-speed operation at 40 Gbps and beyond.

  13. Metallomics for drug development: a further insight into intracellular activation chemistry of a ruthenium(III)-based anticancer drug gained using a multidimensional analytical approach.

    PubMed

    Matczuk, Magdalena; Prządka, Monika; Aleksenko, Svetlana S; Czarnocki, Zbigniew; Pawlak, Katarzyna; Timerbaev, Andrei R; Jarosz, Maciej

    2014-01-01

    The mechanism by which the most relevant ruthenium anticancer drugs are activated in tumors to commence their tumor-inhibiting action remains one of the challenging research tasks of present-day metallomics. This contribution aims to capture and identify eventually more reactive species of one of two bis-indazole tetrachloridoruthenate(III) compounds that are progressing in clinical trials. In view of the fact that the transport of ruthenium into cancer cells is governed by transferrin receptors, the susceptibility of the Ru drug adduct with holo-transferrin to exposure by glutathione and ascorbic acid (at their cancer cytosol concentrations) was studied by inductively coupled plasma mass spectrometry (ICP-MS), following isolation of the reaction products by ultrafiltration. Next, capillary electrophoresis coupled to ICP-MS was applied to monitor changes in the Ru speciation both under simulated cancer cytosol conditions and in real cytosol and to assign the charge state of novel metal species. The latter were identified by using tandem electrospray ionization MS in the respective ion mode. The formation of ruthenium(II) species was for the first time revealed, in which the central metal is coordinated by the reduced (GSH) or the oxidized (GSSG) form of glutathione, i.e. [Ru(II)HindCl4(GSH)](2-) and [Ru(II)HindCl4(GSSG)](2-), respectively (Hind = indazole). Ascorbic acid released the ruthenium functionality from the protein-bound form in a different way, the products of adduct cleavage containing aqua ligands. Distribution of low-molecular mass species of Ru in human cytosol was found to have very much in common with the ruthenium speciation assayed under simulated cytosol conditions.

  14. Using of Teleconference as a Medium to Establish an "E-Global-Learning-System": An Experience of 1000guru-Association on Facilitates Open and Distance Learning Activities with Schools in Indonesia

    ERIC Educational Resources Information Center

    Haris, Ikhfan

    2014-01-01

    Information communication and technology (ICT) has been used in various fields. The use of teleconference for teaching and learning activities is currently not a new topic in global world. In Indonesia, through IMHERE Program from Directorate of Higher Education, some universities have been connected with a network of teleconference as a medium of…

  15. Optimum Reliability of Gain Scores.

    ERIC Educational Resources Information Center

    Sharma, K. K.; Gupta, J. K.

    1986-01-01

    This paper gives a mathematical treatment to findings of Zimmerman and Williams and establishes a minimum reliability for gain scores when the pretest and posttest have equal reliabilities and equal standard deviations. It discusses the behavior of the reliability of gain scores in terms of variations in other test parameters. (Author/LMO)

  16. Computer algorithm for coding gain

    NASA Technical Reports Server (NTRS)

    Dodd, E. E.

    1974-01-01

    Development of a computer algorithm for coding gain for use in an automated communications link design system. Using an empirical formula which defines coding gain as used in space communications engineering, an algorithm is constructed on the basis of available performance data for nonsystematic convolutional encoding with soft-decision (eight-level) Viterbi decoding.

  17. Lack of evidence of chalone activity in used medium and extract of JB-1 tumor cells in vitro. A flow cytometry study.

    PubMed

    Naeser, F K; Barfod, N M; Bichel, P

    1978-02-14

    In cell-free mouse ascites fluid from the JB-1 ascites tumor in the plateau phase of growth low-molecular chalone substances have been found which reversibly and specifically arrest JB-1 cells in the G1 and G2 phase of the cell cycle. The aim of this study was to investigate whether chalones were involved in the regulation of in vitro growth of JB-1 tumor cells. Used medium and cell extract from confluent, stationary JB-1 cell cultures were investigated for proliferation-inhibitory properties. JB-1 cells from stationary cultures were explanted in test cultures and the traverse of cells through the S phase was investigated by means of flow cytometry (FCM). Inhibition--expressed as a delay of the traverse of cells through the S phase--was not observed when a surplus of used medium, concentrated and fractionated used medium or concentrated and fractionated cell extract from JB-1 cells in vitro was added to test cultures. On the contrary, used medium and concentrated and fractionated used medium stimulated growth. Thus, no involvement of chalones in the growth regulation of JB-1 tumor cells in vitro was detected.

  18. Cascade amps for increased subsystem gain

    NASA Astrophysics Data System (ADS)

    Galla, Timothy J.

    1990-05-01

    Selecting cascadable TO-8 amplifiers integrated onto microstrip circuit boards is considered from the point of view of cascaded circuit design techniques and performance characteristics. Cascaded assemblies and circuit boards used in cascaded-amplifier applications are presented. It is noted that TO-8 package constrains allow as many as three transistor stages per housing, utilizing either passive or active biasing with choke decoupling; these configurations can achieve broadband performance with small-signal gain of 15 to 20 dB. Where higher gain levels are required, TO-8 amplifiers can be cascaded as gain blocks and assembled into aluminum housing with connectors. Increased reflection losses resulting in a higher voltage standing wave ratio are analyzed, along with noise minimization techniques. A model showing how to find a TO-8 amplifier's noise figure, input power, and third-order intercept point is described.

  19. Image formation using stimulated raman scattering gain

    NASA Astrophysics Data System (ADS)

    Bespalov, V. G.; Makarov, E. A.; Stasel'ko, D. I.

    2016-07-01

    Theoretical analysis of the spatial, noise, and energy characteristics of an amplifier has been performed in the mode of spectral and time selection using subnanosecond stimulated Raman Scattering gain of weak echo signals in crystalline active media that are known for high (up to 10-1 cm/MW) gain coefficients. The possibility to reach high gain values has been demonstrated for weak signals from objects at acceptable angular sizes of the field of vision of an amplifier. To provide a signal-to-noise ratio that exceeds unity over the entire field of vision, the number of photons at the input to an amplifier that is required has to exceed the number of its resolution elements. Accurate determination of the possibilities of recording of weak echo signals and quality of images of targets that are obtained using amplifiers under stimulated Raman Scattering requires additional special experiments.

  20. Gaining approval for clinical research.

    PubMed

    Cobb, Vanessa; Srinivasan, Neil; Lambiase, Pier

    2016-07-01

    Set-up and delivery of a clinical research project can be complicated and difficult. This article introduces the regulatory processes involved in gaining approval for clinical research and discusses the obstacles that may be encountered. PMID:27388381

  1. Classification of a frameshift/extended and a stop mutation in WT1 as gain-of-function mutations that activate cell cycle genes and promote Wilms tumour cell proliferation

    PubMed Central

    Busch, Maike; Schwindt, Heinrich; Brandt, Artur; Beier, Manfred; Görldt, Nicole; Romaniuk, Paul; Toska, Eneda; Roberts, Stefan; Royer, Hans-Dieter; Royer-Pokora, Brigitte

    2014-01-01

    The WT1 gene encodes a zinc finger transcription factor important for normal kidney development. WT1 is a suppressor for Wilms tumour development and an oncogene for diverse malignant tumours. We recently established cell lines from primary Wilms tumours with different WT1 mutations. To investigate the function of mutant WT1 proteins, we performed WT1 knockdown experiments in cell lines with a frameshift/extension (p.V432fsX87 = Wilms3) and a stop mutation (p.P362X = Wilms2) of WT1, followed by genome-wide gene expression analysis. We also expressed wild-type and mutant WT1 proteins in human mesenchymal stem cells and established gene expression profiles. A detailed analysis of gene expression data enabled us to classify the WT1 mutations as gain-of-function mutations. The mutant WT1Wilms2 and WT1Wilms3 proteins acquired an ability to modulate the expression of a highly significant number of genes from the G2/M phase of the cell cycle, and WT1 knockdown experiments showed that they are required for Wilms tumour cell proliferation. p53 negatively regulates the activity of a large number of these genes that are also part of a core proliferation cluster in diverse human cancers. Our data strongly suggest that mutant WT1 proteins facilitate expression of these cell cycle genes by antagonizing transcriptional repression mediated by p53. We show that mutant WT1 can physically interact with p53. Together the findings show for the first time that mutant WT1 proteins have a gain-of-function and act as oncogenes for Wilms tumour development by regulating Wilms tumour cell proliferation. PMID:24619359

  2. Adaptive allocation of attentional gain

    PubMed Central

    Scolari, Miranda; Serences, John T.

    2009-01-01

    Humans are adept at distinguishing between stimuli that are very similar, an ability that is particularly crucial when the outcome is of serious consequence (e.g. for a surgeon or air traffic controller). Traditionally, selective attention was thought to facilitate perception by increasing the gain of sensory neurons tuned to the defining features of a behaviorally relevant object (e.g. color, orientation, etc.). In contrast, recent mathematical models counter-intuitively suggest that in many cases attentional gain should be applied to neurons that are tuned away from relevant features, especially when discriminating highly similar stimuli. Here we used psychophysical methods to critically evaluate these ‘ideal observer’ models. The data demonstrate that attention enhances the gain of the most informative sensory neurons, even when these neurons are tuned away from the behaviorally relevant target feature. Moreover, the degree to which an individual adopted optimal attentional gain settings by the end of testing predicted success rates on a difficult visual discrimination task, as well as the amount of task improvement that occurred across repeated testing sessions (learning). Contrary to most traditional accounts, these observations suggest that the primary function of attentional gain is not simply to enhance the representation of target features, but to optimize performance on the current perceptual task. Additionally, individual differences in gain suggest that the operating characteristics of low-level attentional phenomena are not stable trait-like attributes and that variability in how attention is deployed may play an important role in determining perceptual abilities. PMID:19776279

  3. Developmental gains in visuospatial memory predict gains in mathematics achievement.

    PubMed

    Li, Yaoran; Geary, David C

    2013-01-01

    Visuospatial competencies are related to performance in mathematical domains in adulthood, but are not consistently related to mathematics achievement in children. We confirmed the latter for first graders and demonstrated that children who show above average first-to-fifth grade gains in visuospatial memory have an advantage over other children in mathematics. The study involved the assessment of the mathematics and reading achievement of 177 children in kindergarten to fifth grade, inclusive, and their working memory capacity and processing speed in first and fifth grade. Intelligence was assessed in first grade and their second to fourth grade teachers reported on their in-class attentive behavior. Developmental gains in visuospatial memory span (d = 2.4) were larger than gains in the capacity of the central executive (d = 1.6) that in turn were larger than gains in phonological memory span (d = 1.1). First to fifth grade gains in visuospatial memory and in speed of numeral processing predicted end of fifth grade mathematics achievement, as did first grade central executive scores, intelligence, and in-class attentive behavior. The results suggest there are important individual differences in the rate of growth of visuospatial memory during childhood and that these differences become increasingly important for mathematics learning. PMID:23936154

  4. Developmental Gains in Visuospatial Memory Predict Gains in Mathematics Achievement

    PubMed Central

    Li, Yaoran; Geary, David C.

    2013-01-01

    Visuospatial competencies are related to performance in mathematical domains in adulthood, but are not consistently related to mathematics achievement in children. We confirmed the latter for first graders and demonstrated that children who show above average first-to-fifth grade gains in visuospatial memory have an advantage over other children in mathematics. The study involved the assessment of the mathematics and reading achievement of 177 children in kindergarten to fifth grade, inclusive, and their working memory capacity and processing speed in first and fifth grade. Intelligence was assessed in first grade and their second to fourth grade teachers reported on their in-class attentive behavior. Developmental gains in visuospatial memory span (d = 2.4) were larger than gains in the capacity of the central executive (d = 1.6) that in turn were larger than gains in phonological memory span (d = 1.1). First to fifth grade gains in visuospatial memory and in speed of numeral processing predicted end of fifth grade mathematics achievement, as did first grade central executive scores, intelligence, and in-class attentive behavior. The results suggest there are important individual differences in the rate of growth of visuospatial memory during childhood and that these differences become increasingly important for mathematics learning. PMID:23936154

  5. Developmental gains in visuospatial memory predict gains in mathematics achievement.

    PubMed

    Li, Yaoran; Geary, David C

    2013-01-01

    Visuospatial competencies are related to performance in mathematical domains in adulthood, but are not consistently related to mathematics achievement in children. We confirmed the latter for first graders and demonstrated that children who show above average first-to-fifth grade gains in visuospatial memory have an advantage over other children in mathematics. The study involved the assessment of the mathematics and reading achievement of 177 children in kindergarten to fifth grade, inclusive, and their working memory capacity and processing speed in first and fifth grade. Intelligence was assessed in first grade and their second to fourth grade teachers reported on their in-class attentive behavior. Developmental gains in visuospatial memory span (d = 2.4) were larger than gains in the capacity of the central executive (d = 1.6) that in turn were larger than gains in phonological memory span (d = 1.1). First to fifth grade gains in visuospatial memory and in speed of numeral processing predicted end of fifth grade mathematics achievement, as did first grade central executive scores, intelligence, and in-class attentive behavior. The results suggest there are important individual differences in the rate of growth of visuospatial memory during childhood and that these differences become increasingly important for mathematics learning.

  6. Reflection of processes of non-equilibrium two-phase filtration in oil-saturated hierarchical medium in data of active wave geophysical monitoring

    NASA Astrophysics Data System (ADS)

    Hachay, Olga; Khachay, Andrey; Khachay, Oleg

    2016-04-01

    The processes of oil extraction from deposit are linked with the movement of multi-phase multi-component media, which are characterized by non-equilibrium and non-linear rheological features. The real behavior of layered systems is defined by the complexity of the rheology of moving fluids and the morphology structure of the porous medium, and also by the great variety of interactions between the fluid and the porous medium [Hasanov and Bulgakova, 2003]. It is necessary to take into account these features in order to informatively describe the filtration processes due to the non-linearity, non-equilibrium and heterogeneity that are features of real systems. In this way, new synergetic events can be revealed (namely, a loss of stability when oscillations occur, and the formation of ordered structures). This allows us to suggest new methods for the control and management of complicated natural systems that are constructed on account of these phenomena. Thus the layered system, from which it is necessary to extract the oil, is a complicated dynamical hierarchical system. A comparison is provided of non-equilibrium effects of the influence of independent hydrodynamic and electromagnetic induction on an oil layer and the medium which it surrounds. It is known that by drainage and steeping the hysteresis effect on curves of the relative phase permeability in dependence on the porous medium's water saturation in some cycles of influence (drainage-steep-drainage) is observed. Using the earlier developed 3D method of induction electromagnetic frequency geometric monitoring, we showed the possibility of defining the physical and structural features of a hierarchical oil layer structure and estimating the water saturation from crack inclusions. This effect allows managing the process of drainage and steeping the oil out of the layer by water displacement. An algorithm was constructed for 2D modeling of sound diffraction on a porous fluid-saturated intrusion of a hierarchical

  7. Synthetic laser medium

    DOEpatents

    Stokowski, Stanley E.

    1989-01-01

    A laser medium is particularly useful in high average power solid state lasers. The laser medium includes a chormium dopant and preferably neodymium ions as codopant, and is primarily a gadolinium scandium gallium garnet, or an analog thereof. Divalent cations inhibit spiral morphology as large boules from which the laser medium is derived are grown, and a source of ions convertible between a trivalent state and a tetravalent state at a low ionization energy are in the laser medium to reduce an absorption coefficient at about one micron wavelength otherwise caused by the divalent cations. These divalent cations and convertible ions are dispersed in the laser medium. Preferred convertible ions are provided from titanium or cerium sources.

  8. Synthetic laser medium

    DOEpatents

    Stokowski, S.E.

    1987-10-20

    A laser medium is particularly useful in high average power solid state lasers. The laser medium includes a chromium dopant and preferably neodymium ions as codopant, and is primarily a gadolinium scandium gallium garnet, or an analog thereof. Divalent cations inhibit spiral morphology as large boules from which the laser medium is derived are grown, and a source of ions convertible between a trivalent state and a tetravalent state at a low ionization energy are in the laser medium to reduce an absorption coefficient at about one micron wavelength otherwise caused by the divalent cations. These divalent cations and convertible ions are dispersed in the laser medium. Preferred convertible ions are provided from titanium or cerium sources.

  9. Gain properties of dye-doped polymer thin films

    NASA Astrophysics Data System (ADS)

    Gozhyk, I.; Boudreau, M.; Haghighi, H. Rabbani; Djellali, N.; Forget, S.; Chénais, S.; Ulysse, C.; Brosseau, A.; Pansu, R.; Audibert, J.-F.; Gauvin, S.; Zyss, J.; Lebental, M.

    2015-12-01

    Hybrid pumping appears as a promising compromise in order to reach the much coveted goal of an electrically pumped organic laser. In such configuration the organic material is optically pumped by an electrically pumped inorganic device on a chip. This engineering solution requires therefore an optimization of the organic gain medium under optical pumping. Here, we report a detailed study of the gain features of dye-doped polymer thin films. In particular we introduce the gain efficiency K , in order to facilitate comparison between different materials and experimental conditions. The gain efficiency was measured with a variety of experimental methods (pump-probe amplification, variable stripe length method, laser thresholds) in order to study several factors which modify the actual gain of a layer, namely the confinement factor, the pump polarization, the molecular anisotropy, and the re-absorption. For instance, for a 600-nm-thick 5-wt % DCM doped poly(methyl methacrylate) (PMMA) layer, the different experimental approaches give a consistent value of K ≃ 80 -cm MW-1 . On the contrary, the usual model predicting the gain from the characteristics of the material leads to an overestimation by two orders of magnitude, which raises a serious problem in the design of actual devices. In this context, we demonstrate the feasibility to infer the gain efficiency from the laser threshold of well-calibrated devices. Temporal measurements at the picosecond scale were carried out to support the analysis.

  10. Ca2+ enrichment in culture medium potentiates effect of oligonucleotides

    PubMed Central

    Hori, Shin-ichiro; Yamamoto, Tsuyoshi; Waki, Reiko; Wada, Shunsuke; Wada, Fumito; Noda, Mio; Obika, Satoshi

    2015-01-01

    Antisense and RNAi-related oligonucleotides have gained attention as laboratory tools and therapeutic agents based on their ability to manipulate biological events in vitro and in vivo. We show that Ca2+ enrichment of medium (CEM) potentiates the in vitro activity of multiple types of oligonucleotides, independent of their net charge and modifications, in various cells. In addition, CEM reflects in vivo silencing activity more consistently than conventional transfection methods. Microscopic analysis reveals that CEM provides a subcellular localization pattern of oligonucleotides resembling that obtained by unassisted transfection, but with quantitative improvement. Highly monodispersed nanoparticles ∼100 nm in size are found in Ca2+-enriched serum-containing medium regardless of the presence or absence of oligonucleotides. Transmission electron microscopy analysis reveals that the 100-nm particles are in fact an ensemble of much smaller nanoparticles (ϕ ∼ 15 nm). The presence of these nanoparticles is critical for the efficient uptake of various oligonucleotides. In contrast, CEM is ineffective for plasmids, which are readily transfected via the conventional calcium phosphate method. Collectively, CEM enables a more accurate prediction of the systemic activity of therapeutic oligonucleotides, while enhancing the broad usability of oligonucleotides in the laboratory. PMID:26101258

  11. Ca2+ enrichment in culture medium potentiates effect of oligonucleotides.

    PubMed

    Hori, Shin-Ichiro; Yamamoto, Tsuyoshi; Waki, Reiko; Wada, Shunsuke; Wada, Fumito; Noda, Mio; Obika, Satoshi

    2015-10-30

    Antisense and RNAi-related oligonucleotides have gained attention as laboratory tools and therapeutic agents based on their ability to manipulate biological events in vitro and in vivo. We show that Ca(2+) enrichment of medium (CEM) potentiates the in vitro activity of multiple types of oligonucleotides, independent of their net charge and modifications, in various cells. In addition, CEM reflects in vivo silencing activity more consistently than conventional transfection methods. Microscopic analysis reveals that CEM provides a subcellular localization pattern of oligonucleotides resembling that obtained by unassisted transfection, but with quantitative improvement. Highly monodispersed nanoparticles ~100 nm in size are found in Ca(2+)-enriched serum-containing medium regardless of the presence or absence of oligonucleotides. Transmission electron microscopy analysis reveals that the 100-nm particles are in fact an ensemble of much smaller nanoparticles (ϕ ∼ 15 nm). The presence of these nanoparticles is critical for the efficient uptake of various oligonucleotides. In contrast, CEM is ineffective for plasmids, which are readily transfected via the conventional calcium phosphate method. Collectively, CEM enables a more accurate prediction of the systemic activity of therapeutic oligonucleotides, while enhancing the broad usability of oligonucleotides in the laboratory.

  12. Coherent amplification and noise in gain-enhanced nanoplasmonic metamaterials: a Maxwell-Bloch Langevin approach.

    PubMed

    Pusch, Andreas; Wuestner, Sebastian; Hamm, Joachim M; Tsakmakidis, Kosmas L; Hess, Ortwin

    2012-03-27

    Nanoplasmonic metamaterials are an exciting new class of engineered media that promise a range of important applications, such as subwavelength focusing, cloaking, and slowing/stopping of light. At optical frequencies, using gain to overcome potentially not insignificant losses has recently emerged as a viable solution to ultra-low-loss operation that may lead to next-generation active metamaterials. Maxwell-Bloch models for active nanoplasmonic metamaterials are able to describe the coherent spatiotemporal and nonlinear gain-plasmon dynamics. Here, we extend the Maxwell-Bloch theory to a Maxwell-Bloch Langevin approach-a spatially resolved model that describes the light field and noise dynamics in gain-enhanced nanoplasmonic structures. Using the example of an optically pumped nanofishnet metamaterial with an embedded laser dye (four-level) medium exhibiting a negative refractive index, we demonstrate the transition from loss-compensation to amplification and to nanolasing. We observe ultrafast relaxation oscillations of the bright negative-index mode with frequencies just below the THz regime. The influence of noise on mode competition and the onset and magnitude of the relaxation oscillations is elucidated, and the dynamics and spectra of the emitted light indicate that coherent amplification and lasing are maintained even in the presence of noise and amplified spontaneous emission.

  13. Antidiabetic activity of medium-polar extract from the leaves of Stevia rebaudiana Bert. (Bertoni) on alloxan-induced diabetic rats

    PubMed Central

    Misra, Himanshu; Soni, Manish; Silawat, Narendra; Mehta, Darshana; Mehta, B. K.; Jain, D. C.

    2011-01-01

    Objective: To investigate the medicative effects of medium-polar (benzene:acetone, 1:1, v/v) extract of leaves from Stevia rebaudiana (family Asteraceae) on alloxan-induced diabetic rats. Materials and Methods: Diabetes was induced in adult albino Wistar rats by intraperitoneal (i.p.) injection of alloxan (180 mg/kg). Medium-polar extract was administered orally at daily dose of 200 and 400 mg/kg body wt. basis for 10 days. The control group received normal saline (0.9%) for the same duration. Glibenclamide was used as positive control reference drug against Stevia extract. Results: Medium-polar leaf extract of S. rebaudiana (200 and 400 mg/kg) produced a delayed but significant (P < 0.01) decrease in the blood glucose level, without producing condition of hypoglycemia after treatment, together with lesser loss in the body weight as compared with standard positive control drug glibenclamide. Conclusions: Treatment of diabetes with sulfonylurea drugs (glibenclamide) causes hypoglycemia followed by greater reduction in body weight, which are the most worrisome effects of these drugs. Stevia extract was found to antagonize the necrotic action of alloxan and thus had a re-vitalizing effect on β-cells of pancreas. PMID:21687353

  14. High current gain transistor laser.

    PubMed

    Liang, Song; Qiao, Lijun; Zhu, Hongliang; Wang, Wei

    2016-06-10

    A transistor laser (TL), having the structure of a transistor with multi-quantum wells near its base region, bridges the functionality gap between lasers and transistors. However, light emission is produced at the expense of current gain for all the TLs reported up to now, leading to a very low current gain. We propose a novel design of TLs, which have an n-doped InP layer inserted in the emitter ridge. Numerical studies show that a current flow aperture for only holes can be formed in the center of the emitter ridge. As a result, the common emitter current gain can be as large as 143.3, which is over 15 times larger than that of a TL without the aperture. Besides, the effects of nonradiative recombination defects can be reduced greatly because the flow of holes is confined in the center region of the emitter ridge.

  15. Commutated automatic gain control system

    NASA Technical Reports Server (NTRS)

    Yost, S. R.

    1981-01-01

    A commutated automatic gain control system (AGC) was designed and constructed for the prototype Loran C receiver. The AGC is designed to improve the signal-to-signal ratio of the received Loran signals. The AGC design does not require any analog to digital conversion and it utilizes commonly available components. The AGC consists of: (1) a circuit which samples the peak of the envelope of the Loran signal to obtain an AGC voltage for each of three Loran stations, (2) a dc gain circuit to control the overall gain of the AGC system, and (3) an AGC amplification of the input RF signal. The performance of the AGC system was observed in bench and flight tests; it has improved the overall accuracy of the receiver. Improvements in the accuracy of the time difference calculations to within approx. + or - 1.5 microseconds of the observed time differnces for a given position are reported.

  16. High current gain transistor laser

    NASA Astrophysics Data System (ADS)

    Liang, Song; Qiao, Lijun; Zhu, Hongliang; Wang, Wei

    2016-06-01

    A transistor laser (TL), having the structure of a transistor with multi-quantum wells near its base region, bridges the functionality gap between lasers and transistors. However, light emission is produced at the expense of current gain for all the TLs reported up to now, leading to a very low current gain. We propose a novel design of TLs, which have an n-doped InP layer inserted in the emitter ridge. Numerical studies show that a current flow aperture for only holes can be formed in the center of the emitter ridge. As a result, the common emitter current gain can be as large as 143.3, which is over 15 times larger than that of a TL without the aperture. Besides, the effects of nonradiative recombination defects can be reduced greatly because the flow of holes is confined in the center region of the emitter ridge.

  17. High current gain transistor laser

    PubMed Central

    Liang, Song; Qiao, Lijun; Zhu, Hongliang; Wang, Wei

    2016-01-01

    A transistor laser (TL), having the structure of a transistor with multi-quantum wells near its base region, bridges the functionality gap between lasers and transistors. However, light emission is produced at the expense of current gain for all the TLs reported up to now, leading to a very low current gain. We propose a novel design of TLs, which have an n-doped InP layer inserted in the emitter ridge. Numerical studies show that a current flow aperture for only holes can be formed in the center of the emitter ridge. As a result, the common emitter current gain can be as large as 143.3, which is over 15 times larger than that of a TL without the aperture. Besides, the effects of nonradiative recombination defects can be reduced greatly because the flow of holes is confined in the center region of the emitter ridge. PMID:27282466

  18. Welfare Gains from Financial Liberalization

    PubMed Central

    Townsend, Robert M.; Ueda, Kenichi

    2010-01-01

    Financial liberalization has been a controversial issue, as empirical evidence for growth enhancing effects is mixed. Here, we find sizable welfare gains from liberalization (cost to repression), though the gain in economic growth is ambiguous. We take the view that financial liberalization is a government policy that alters the path of financial deepening, while financial deepening is endogenously chosen by agents given a policy and occurs in transition towards a distant steady state. This history-dependent view necessitates the use of simulation analysis based on a growth model. Our application is a specific episode: Thailand from 1976 to 1996. PMID:20806055

  19. High gain photoconductive semiconductor switching

    SciTech Connect

    Zutavern, F.J.; Loubriel, G.M.; O'Malley, M.W.; Helgeson, W.D.; McLaughlin, D.L.

    1991-01-01

    Switching properties are reported for high gain photoconductive semiconductor switches (PCSS). A 200 ps pulse width laser was used in tests to examine the relations between electric field, rise time, delay, and minimum optical trigger energy for switches which reached 80 kV in a 50 {Omega} transmission line with rise times as short as 600 ps. Infrared photoluminescence was imaged during high gain switching providing direct evidence for current filamentation. Implications of these measurements for the theoretical understanding and practical development of these switches are discussed. 16 refs., 10 figs.

  20. Strongly localized moving discrete dissipative breather-solitons in Kerr nonlinear media supported by intrinsic gain

    NASA Astrophysics Data System (ADS)

    Johansson, Magnus; Prilepsky, Jaroslaw E.; Derevyanko, Stanislav A.

    2014-04-01

    We investigate the mobility of nonlinear localized modes in a generalized discrete Ginzburg-Landau-type model, describing a one-dimensional waveguide array in an active Kerr medium with intrinsic, saturable gain and damping. It is shown that exponentially localized, traveling discrete dissipative breather-solitons may exist as stable attractors supported only by intrinsic properties of the medium, i.e., in the absence of any external field or symmetry-breaking perturbations. Through an interplay by the gain and damping effects, the moving soliton may overcome the Peierls-Nabarro barrier, present in the corresponding conservative system, by self-induced time-periodic oscillations of its power (norm) and energy (Hamiltonian), yielding exponential decays to zero with different rates in the forward and backward directions. In certain parameter windows, bistability appears between fast modes with small oscillations and slower, large-oscillation modes. The velocities and the oscillation periods are typically related by lattice commensurability and exhibit period-doubling bifurcations to chaotically "walking" modes under parameter variations. If the model is augmented by intersite Kerr nonlinearity, thereby reducing the Peierls-Nabarro barrier of the conservative system, the existence regime for moving solitons increases considerably, and a richer scenario appears including Hopf bifurcations to incommensurately moving solutions and phase-locking intervals. Stable moving breathers also survive in the presence of weak disorder.

  1. Chemically defined medium and Caenorhabditis elegans

    NASA Technical Reports Server (NTRS)

    Szewczyk, Nathaniel J.; Kozak, Elena; Conley, Catharine A.

    2003-01-01

    BACKGROUND: C. elegans has been established as a powerful genetic system. Use of a chemically defined medium (C. elegans Maintenance Medium (CeMM)) now allows standardization and systematic manipulation of the nutrients that animals receive. Liquid cultivation allows automated culturing and experimentation and should be of use in large-scale growth and screening of animals. RESULTS: We find that CeMM is versatile and culturing is simple. CeMM can be used in a solid or liquid state, it can be stored unused for at least a year, unattended actively growing cultures may be maintained longer than with standard techniques, and standard C. elegans protocols work well with animals grown in defined medium. We also find that there are caveats to using defined medium. Animals in defined medium grow more slowly than on standard medium, appear to display adaptation to the defined medium, and display altered growth rates as they change the composition of the defined medium. CONCLUSIONS: As was suggested with the introduction of C. elegans as a potential genetic system, use of defined medium with C. elegans should prove a powerful tool.

  2. Inhibition of Hyperpolarization-Activated Cation Current in Medium-Sized DRG Neurons Contributed to the Antiallodynic Effect of Methylcobalamin in the Rat of a Chronic Compression of the DRG.

    PubMed

    Zhang, Ming; Han, Wenjuan; Zheng, Jianyong; Meng, Fancheng; Jiao, Xiying; Hu, Sanjue; Xu, Hui

    2015-01-01

    Recently several lines of evidence demonstrated that methylcobalamin (MeCbl) might have potential analgesic effect in experimental and clinical studies. However, it was reported that MeCbl had no effect on treating lumbar spinal stenosis induced pain. Thus, the effects of short-term and long-term administration of MeCbl were examined in the chronic compression of dorsal root ganglion (CCD) model. We found that mechanical allodynia was significantly inhibited by a continuous application of high dose and a single treatment of a super high dose of MeCbl. Little is known about mechanisms underlying the analgesia of MeCbl. We examined the effect of MeCbl on the spontaneous activity (SA), the excitability, and hyperpolarization-activated nonselective cation ion current in compressed medium-sized dorsal root ganglion (DRG) neurons using extracellular single fiber recording in vivo and whole-cell patch clamp in vitro. We found that MeCbl significantly inhibited the SA of A-type sensory neurons in a dose-dependent manner and inhibited the excitability of medium-sized DRG neurons. In addition, MeCbl also decreased I h current density in injured medium-sized DRG neurons. Our results proved that MeCbl might exert an analgesic effect through the inhibition I h current and then might inhibit the hyperexcitability of primary sensory neurons under neuropathic pain state.

  3. Hydrogen cyanide synthesis and antifungal activity of the biocontrol strain Pseudomonas fluorescens In5 from Greenland is highly dependent on growth medium.

    PubMed

    Michelsen, Charlotte Frydenlund; Stougaard, Peter

    2012-04-01

    Hydrogen cyanide (HCN) is a secondary metabolite produced by many antagonistic Pseudomonas species. In the present study, the gene cluster encoding HCN synthesis in a newly isolated Pseudomonas fluorescens strain, In5, from South Greenland was investigated. Sequence analysis showed that the Greenlandic hcn gene cluster comprises a novel hcn cluster. Transposon mutagenesis of strain In5 resulted in mutants In5-2E1 and In5-1H7 with no production of HCN, and mutant In5-6B9 with reduced HCN synthesis. In mutant In5-2E1, the transposon was inserted into the hcnC gene; in mutant In5-1H7, the Tn5 insertion was found in a region upstream of a putative malate:quinone oxidoreductase gene (mqo); and in mutant In5-6B9, the transposon disrupted a probable enoyl-CoA hydratase/isomerase gene. In vitro inhibition experiments with In5 (wild type) and In5-2E1 (mutant) showed that in nitrogen-rich Luria-Bertani medium, strain In5 but not the hcn mutant In5-2E1 produced HCN and inhibited the growth of hyphae of Rhizoctonia solani and Pythium aphanidermatum . In contrast, when cultivating the strains in the carbohydrate-rich potato dextrose medium, neither of the strains produced any HCN, and thus, they were unable to inhibit hyphal growth of fungi. These experiments strongly indicate that the synthesis of HCN is highly dependent on the growth medium used.

  4. The effects of neural gain on attention and learning.

    PubMed

    Eldar, Eran; Cohen, Jonathan D; Niv, Yael

    2013-08-01

    Attention is commonly thought to be manifest through local variations in neural gain. However, what would be the effects of brain-wide changes in gain? We hypothesized that global fluctuations in gain modulate the breadth of attention and the degree to which processing is focused on aspects of the environment to which one is predisposed to attend. We found that measures of pupil diameter, which are thought to track levels of locus coeruleus norepinephrine activity and neural gain, were correlated with the degree to which learning was focused on stimulus dimensions that individual human participants were more predisposed to process. In support of our interpretation of this effect in terms of global changes in gain, we found that the measured pupillary and behavioral variables were strongly correlated with global changes in the strength and clustering of functional connectivity, as brain-wide fluctuations of gain would predict. PMID:23770566

  5. The Gains from Vertical Scaling

    ERIC Educational Resources Information Center

    Briggs, Derek C.; Domingue, Ben

    2013-01-01

    It is often assumed that a vertical scale is necessary when value-added models depend upon the gain scores of students across two or more points in time. This article examines the conditions under which the scale transformations associated with the vertical scaling process would be expected to have a significant impact on normative interpretations…

  6. Classroom Composition and Achievement Gains.

    ERIC Educational Resources Information Center

    Leiter, Jeffrey

    1983-01-01

    Third-grade students in high ability groups in mathematics achieved greater gains than students in low ability groups. The opposite results occurred in reading achievement. Possible reasons for this difference include different instructional techniques for reading and math and the effect of home environment on learning. (IS)

  7. Simulation of an X-ray laser in the transient gain-saturation regime

    SciTech Connect

    Starikov, F A; Volkov, V A; Gasparyan, P D; Roslov, V I

    2009-09-30

    By using the TRANS code, we performed three-dimensional calculations of amplified spontaneous emission (ASE) in X-ray lasers on the 3p-3s transition in Ne-like Ge ({lambda} = 19.6 nm) and Ti ({lambda} = 2.6 nm) operating in the transient regime upon irradiation of a flat target by a high-power picosecond laser pulse focused into a line with one or two nanosecond prepulses. The hydrodynamics and population kinetics of the active medium of X-ray lasers were calculated by using the SS-9M code. The pulse duration, the gain, the spatial structure of the laser beam and the type of influence of a 'travelling' pump wave on the ASE brightness obtained in calculations are in agreement with the experimental data. The use of the 'travelling pump wave' leads not only to the increase in the ASE brightness but also considerably reduces its angular divergence. (active media)

  8. Sympathetic baroreflex gain in normotensive pregnant women

    PubMed Central

    Usselman, Charlotte W.; Skow, Rachel J.; Matenchuk, Brittany A.; Chari, Radha S.; Julian, Colleen G.; Stickland, Michael K.; Davenport, Margie H.

    2015-01-01

    Muscle sympathetic nerve activity is increased during normotensive pregnancy while mean arterial pressure is maintained or reduced, suggesting baroreflex resetting. We hypothesized spontaneous sympathetic baroreflex gain would be reduced in normotensive pregnant women relative to nonpregnant matched controls. Integrated muscle sympathetic burst incidence and total sympathetic activity (microneurography), blood pressure (Finometer), and R-R interval (ECG) were assessed at rest in 11 pregnant women (33 ± 1 wk gestation, 31 ± 1 yr, prepregnancy BMI: 23.5 ± 0.9 kg/m2) and 11 nonpregnant controls (29 ± 1 yr; BMI: 25.2 ± 1.7 kg/m2). Pregnant women had elevated baseline sympathetic burst incidence (43 ± 2 vs. 33 ± 2 bursts/100 heart beats, P = 0.01) and total sympathetic activity (1,811 ± 148 vs. 1,140 ± 55 au, P < 0.01) relative to controls. Both mean (88 ± 3 vs. 91 ± 2 mmHg, P = 0.4) and diastolic (DBP) (72 ± 3 vs. 73 ± 2 mmHg, P = 0.7) pressures were similar between pregnant and nonpregnant women, respectively, indicating an upward resetting of the baroreflex set point with pregnancy. Baroreflex gain, calculated as the linear relationship between sympathetic burst incidence and DBP, was reduced in pregnant women relative to controls (−3.7 ± 0.5 vs. −5.4 ± 0.5 bursts·100 heart beats−1·mmHg−1, P = 0.03), as was baroreflex gain calculated with total sympathetic activity (−294 ± 24 vs. −210 ± 24 au·100 heart beats−1·mmHg−1; P = 0.03). Cardiovagal baroreflex gain (sequence method) was not different between nonpregnant controls and pregnant women (49 ± 8 vs. 36 ± 8 ms/mmHg; P = 0.2). However, sympathetic (burst incidence) and cardiovagal gains were negatively correlated in pregnant women (R = −0.7; P = 0.02). Together, these data indicate that the influence of the sympathetic nervous system over arterial blood pressure is reduced in normotensive pregnancy, in terms of both long-term and beat-to-beat regulation of arterial pressure

  9. Optofluidic lasers with a single molecular layer of gain.

    PubMed

    Chen, Qiushu; Ritt, Michael; Sivaramakrishnan, Sivaraj; Sun, Yuze; Fan, Xudong

    2014-12-21

    We achieve optofluidic lasers with a single molecular layer of gain, in which green fluorescent protein, dye-labeled bovine serum albumin, and dye-labeled DNA, are used as the gain medium and attached to the surface of a ring resonator via surface immobilization biochemical methods. It is estimated that the surface density of the gain molecules is on the order of 10(12) cm(-2), sufficient for lasing under pulsed optical excitation. It is further shown that the optofluidic laser can be tuned by energy transfer mechanisms through biomolecular interactions. This work not only opens a door to novel photonic devices that can be controlled at the level of a single molecular layer but also provides a promising sensing platform to analyze biochemical processes at the solid-liquid interface.

  10. An aqueous extract from toad skin prevents gelatinase activities derived from fetal serum albumin and serum-free culture medium of human breast carcinoma MDA-MB-231 cells.

    PubMed

    Nakata, Munehiro; Kawaguchi, Shota; Oikawa, Ayami; Inamura, Akito; Nomoto, Shunki; Miyai, Hirokazu; Nonaka, Tomomi; Ichimi, Saeko; Fujita-Yamaguchi, Yoko; Luo, Chuan; Gao, Bo; Tang, Wei

    2015-12-01

    An aqueous extract from toad skin, cinobufacini, has been known to possess anticancer ability. The present study examined effect of toad skin extract on activity of gelatinases including matrix metalloproteinases-2 and -9 which play an important role in invasion of carcinoma cells. Gelatinase activities derived from fetal serum albumin and culture medium of human breast carcinoma cell line MDA-MB-231 were significantly prevented in the presence of toad skin extract. The inhibitory activity was found in water-soluble fraction of the extract prepared by the Bligh & Dyer method but not in CHCl(3)-soluble lipid fraction. These results suggest that an aqueous extract from toad skin contains a water-soluble substance possessing a potent ability to prevent gelatinase activity. In conclusion, the water-soluble substance in toad skin extract cinobufacini may be able to regulate cancer cell migration accelerated by matrix metalloproteinases.

  11. Photomultiplier tube gain regulating system

    DOEpatents

    Johnson, Wayne F.

    1976-01-01

    This invention relates to an improved system for regulating the gain of a photomultiplier tube, and was designed for use with the photomultiplier tubes of a GeMSAEC fast analyzers. It has the following advantages over the prior system: noise is virtually eliminated; sample analysis can begin after 3 to 4 revolutions of the rotor; fluorescent and light scattering solutions can be used as a reference; and the reference solution can be in any cuvette on the rotor.

  12. Cassegrain-Antenna Gain Improvement

    NASA Technical Reports Server (NTRS)

    Galindo, V.; Cha, A. G.; Mittra, R.

    1986-01-01

    Modified antenna feed with dual-shaped subreflectors yields 10-to20-percent improvement in efficiency of existing large-aperture paraboloidal or Cassegrainian antennas. Such offset dual-shaped subreflector (DSS) feed brings gain of existing paraboloid or Cassegrain antennas up to that of reflector antennas of more recent design at cost considerably lower than for reshaping existing reflecting surfaces. Mathematical procedures developed for synthesizing nearly optimum shapes for DSS elements of new feeds.

  13. LiY0.3Lu0.7F4: Ce3+,Pr3+ Mixed Crystal as a Perspective Up-Conversionally Pumped UV Active Medium

    NASA Astrophysics Data System (ADS)

    Gorieva, V. G.; Semashko, V. V.; Korableva, S. L.; Marisov, M. A.; Pavlov, V. V.

    2015-09-01

    Investigation results of effective population of states of 5d-configuration of Ce3+ ions by energy transfer from Pr3+ ions in LiY0.3Lu0.7F4 (LYLF) crystals are discussed. The real concentrations of Pr3+ and Ce3+ ions in LYLF crystals are determined. Such parameters as excited 4f-5d state photoionization cross-section of Pr3+ ions, ground state cross-section of Ce3+ ions at 266 nm wavelengths and energy transfer coefficients of energy transfer from Pr3+ to Ce3+ ions were estimated. The results of pump-probe experiments on 5d-4f transitions of Ce3+ ions in LYLF crystals are presented. The optimal parameters for getting maximal gain on 5d-4f transitions of Ce3+ ions were determined by mathematical modeling.

  14. Hypermedia as medium

    NASA Technical Reports Server (NTRS)

    Dede, Christopher J.

    1990-01-01

    Claims and rebuttals that hypermedia (the associative, nonlinear interconnection of multimedia materials) is a fundamentally innovative means of thinking and communicating are described. This representational architecture has many advantages that make it a major advance over other media; however, it also has several intrinsic problems that severly limits its effectiveness as a medium. These advantages and limits in applications are discussed.

  15. Holographic recording medium

    NASA Technical Reports Server (NTRS)

    Gange, Robert Allen (Inventor)

    1977-01-01

    A holographic recording medium comprising a conductive substrate, a photoconductive layer and an electrically alterable layer of a linear, low molecular weight hydrocarbon polymer has improved fatigue resistance. An acrylic barrier layer can be interposed between the photoconductive and electrically alterable layers.

  16. Effect of the structural characteristics of binary Pt-Ru and ternary Pt-Ru-M fuel cell catalysts on the activity of ethanol electrooxidation in acid medium.

    PubMed

    Antolini, Ermete

    2013-06-01

    In view of their possible use as anode materials in acid direct ethanol fuel cells, the electrocatalytic activity of Pt-Ru and Pt-Ru-M catalysts for ethanol oxidation has been investigated. This minireview examines the effects of the structural characteristics of Pt-Ru, such as the degree of alloying and Ru oxidation state, on the electrocatalytic activity for ethanol oxidation.

  17. Commutated automatic gain control system

    NASA Technical Reports Server (NTRS)

    Yost, S. R.

    1982-01-01

    A commutated automatic gain control (AGC) system was designed and built for a prototype Loran C receiver. The receiver uses a microcomputer to control a memory aided phase-locked loop (MAPLL). The microcomputer also controls the input/output, latitude/longitude conversion, and the recently added AGC system. The circuit designed for the AGC is described, and bench and flight test results are presented. The AGC circuit described actually samples starting at a point 40 microseconds after a zero crossing determined by the software lock pulse ultimately generated by a 30 microsecond delay and add network in the receiver front end envelope detector.

  18. Scalar gain interpretation of large order filters

    NASA Technical Reports Server (NTRS)

    Mason, Paul A. C.; Mook, D. Joseph

    1993-01-01

    A technique is developed which demonstrates how to interpret a large fully-populated filter gain matrix as a set of scalar gains. The inverse problem is also solved, namely, how to develop a large-order filter gain matrix from a specified set of scalar gains. Examples are given to illustrate the method.

  19. A gain-coefficient switched Alexandrite laser

    NASA Astrophysics Data System (ADS)

    Lee, Chris J.; van der Slot, Peter J. M.; Boller, Klaus-J.

    2013-01-01

    We report on a gain-coefficient switched Alexandrite laser. An electro-optic modulator is used to switch between high and low gain states by making use of the polarization dependent gain of Alexandrite. In gain-coefficient switched mode, the laser produces 85 ns pulses with a pulse energy of 240 mJ at a repetition rate of 5 Hz.

  20. Development and Demonstration of a Low Cost Hybrid Drive Train for Medium and Heavy Duty Vehicles

    SciTech Connect

    Strangas, Elias; Schock, Harold; Zhu, Guoming; Moran, Kevin; Ruckle, Trevor; Foster, Shanelle; Cintron-Rivera, Jorge; Tariq, Abdul; Nino-Baron, Carlos

    2011-04-30

    The DOE sponsored effort is part of a larger effort to quantify the efficiency of hybrid powertrain systems through testing and modeling. The focus of the DOE sponsored activity was the design, development and testing of hardware to evaluate the efficiency of the electrical motors relevant to medium duty vehicles. Medium duty hybrid powertrain motors and generators were designed, fabricated, setup and tested. The motors were a permanent magnet configuration, constructed at Electric Apparatus Corporation in Howell, Michigan. The purpose of this was to identify the potential gains in terms of fuel cost savings that could be realized by implementation of such a configuration. As the electric motors constructed were prototype designs, the scope of the project did not include calculation of the costs of mass production of the subject electrical motors or generator.

  1. Collaborative Manufacturing for Small-Medium Enterprises

    NASA Astrophysics Data System (ADS)

    Irianto, D.

    2016-02-01

    Manufacturing systems involve decisions concerning production processes, capacity, planning, and control. In a MTO manufacturing systems, strategic decisions concerning fulfilment of customer requirement, manufacturing cost, and due date of delivery are the most important. In order to accelerate the decision making process, research on decision making structure when receiving order and sequencing activities under limited capacity is required. An effective decision making process is typically required by small-medium components and tools maker as supporting industries to large industries. On one side, metal small-medium enterprises are expected to produce parts, components or tools (i.e. jigs, fixture, mold, and dies) with high precision, low cost, and exact delivery time. On the other side, a metal small- medium enterprise may have weak bargaining position due to aspects such as low production capacity, limited budget for material procurement, and limited high precision machine and equipment. Instead of receiving order exclusively, a small-medium enterprise can collaborate with other small-medium enterprise in order to fulfill requirements high quality, low manufacturing cost, and just in time delivery. Small-medium enterprises can share their best capabilities to form effective supporting industries. Independent body such as community service at university can take a role as a collaboration manager. The Laboratory of Production Systems at Bandung Institute of Technology has implemented shared manufacturing systems for small-medium enterprise collaboration.

  2. Catalase-like activity of bovine met-hemoglobin: interaction with the pseudo-catalytic peroxidation of anthracene traces in aqueous medium.

    PubMed

    Paco, Laveille; Galarneau, Anne; Drone, Jullien; Fajula, François; Bailly, Carole; Pulvin, Sylviane; Thomas, Daniel

    2009-10-01

    Hemoglobin is a member of the hemoprotein superfamily whose main role is to transport O(2) in vertebrate organisms. It has two known promiscuous enzymatic activities, peroxidase and oxygenase. Here we show for the first time that bovine hemoglobin also presents a catalase-like activity characterized by a V(max )of 344 microM/min, a K(M )of 24 mM and a k(cat) equal to 115/min. For high anthracene and hemoglobin concentrations and low hydrogen peroxide concentrations, this activity inhibits the expected oxidation of anthracene, which occurs through a peroxidase-like mechanism. Anthracene belongs to the polycyclic aromatic hydrocarbon (PAH) family whose members are carcinogenic and persistent pollutants found in industrial waste waters. Our results show that anthracene oxidation by hemoglobin and hydrogen peroxide follows a typical bi-bi ping-pong mechanism with a V(max) equal to 0.250 microM/min, K(M(H2O2) )of 80 microM, K(M(ANT)) of 1.1 microM and k(cat) of 0.17/min. The oxidation of anthracene is shown to be pseudo-catalytic because an excess of hemoglobin and hydrogen peroxide is required to make PAH completely disappear. Thus, bovine hemoglobin presents, in different degrees, all the catalytic activities of the hemoprotein group, which makes it a very interesting protein for biotechnological processes and one with which structure-activity relationships can be studied.

  3. Liquid chromatographic extraction medium

    DOEpatents

    Horwitz, E. Philip; Dietz, Mark L.

    1994-01-01

    A method and apparatus for extracting strontium and technetium values from biological, industrial and environmental sample solutions using a chromatographic column is described. An extractant medium for the column is prepared by generating a solution of a diluent containing a Crown ether and dispersing the solution on a resin substrate material. The sample solution is highly acidic and is introduced directed to the chromatographic column and strontium or technetium is eluted using deionized water.

  4. Liquid chromatographic extraction medium

    DOEpatents

    Horwitz, E.P.; Dietz, M.L.

    1994-09-13

    A method and apparatus are disclosed for extracting strontium and technetium values from biological, industrial and environmental sample solutions using a chromatographic column. An extractant medium for the column is prepared by generating a solution of a diluent containing a Crown ether and dispersing the solution on a resin substrate material. The sample solution is highly acidic and is introduced directed to the chromatographic column and strontium or technetium is eluted using deionized water. 1 fig.

  5. Fresnel reflection from a cavity with net roundtrip gain

    SciTech Connect

    Mansuripur, Tobias S.; Mansuripur, Masud

    2014-03-24

    A planewave incident on an active etalon with net roundtrip gain may be expected to diverge in field amplitude, yet applying the Fresnel formalism to Maxwell's equations admits a convergent solution. We describe this solution mathematically and provide additional insight by demonstrating the response of such a cavity to an incident beam of light. Cavities with net roundtrip gain have often been overlooked in the literature, and a clear understanding of their behavior yields insight to negative refraction in nonmagnetic media, a duality between loss and gain, amplified total internal reflection, and the negative-index lens.

  6. High-gain antenna & terrain

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Areas of rocky Martian terrain are seen in this image, taken by the Imager for Mars Pathfinder (IMP) on Sol 2. Portions of a lander petal and deflated airbag are at lower left. The dark disk at center is the high-gain antenna, and the silver cylindrical objects at upper right are part of the antenna's mechanism. An area of relatively smooth terrain is seen at upper right, which may offer clues to how this area was formed, and may be a future target for Sojourner's studies. The black area at lower right and small strip at top center is missing data.

    Mars Pathfinder was developed and managed by the Jet Propulsion Laboratory (JPL) for the National Aeronautics and Space Administration. The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

  7. Redox-active porous coordination polymers prepared by trinuclear heterometallic pivalate linking with the redox-active nickel(II) complex: synthesis, structure, magnetic and redox properties, and electrocatalytic activity in organic compound dehalogenation in heterogeneous medium.

    PubMed

    Lytvynenko, A S; Kolotilov, S V; Kiskin, M A; Cador, O; Golhen, S; Aleksandrov, G G; Mishura, A M; Titov, V E; Ouahab, L; Eremenko, I L; Novotortsev, V M

    2014-05-19

    Linking of the trinuclear pivalate fragment Fe2CoO(Piv)6 by the redox-active bridge Ni(L)2 (compound 1; LH is Schiff base from hydrazide of 4-pyridinecarboxylic acid and 2-pyridinecarbaldehyde, Piv(-) = pivalate) led to formation of a new porous coordination polymer (PCP) {Fe2CoO(Piv)6}{Ni(L)2}1.5 (2). X-ray structures of 1 and 2 were determined. A crystal lattice of compound 2 is built from stacked 2D layers; the Ni(L)2 units can be considered as bridges, which bind two Fe2CoO(Piv)6 units. In desolvated form, 2 possesses a porous crystal lattice (SBET = 50 m(2) g(-1), VDR = 0.017 cm(3) g(-1) estimated from N2 sorption at 78 K). At 298 K, 2 absorbed a significant quantity of methanol (up to 0.3 cm(3) g(-1)) and chloroform. Temperature dependence of molar magnetic susceptibility of 2 could be fitted as superposition of χMT of Fe2CoO(Piv)6 and Ni(L)2 units, possible interactions between them were taken into account using molecular field model. In turn, magnetic properties of the Fe2CoO(Piv)6 unit were fitted using two models, one of which directly took into account a spin-orbit coupling of Co(II), and in the second model the spin-orbit coupling of Co(II) was approximated as zero-field splitting. Electrochemical and electrocatalytic properties of 2 were studied by cyclic voltammetry in suspension and compared with electrochemical and electrocatalytic properties of a soluble analogue 1. A catalytic effect was determined by analysis of the catalytic current dependency on concentrations of the substrate. Compound 1 possessed electrocatalytic activity in organic halide dehalogenation, and such activity was preserved for the Ni(L)2 units, incorporated into the framework of 2. In addition, a new property occurred in the case of 2: the catalytic activity of PCP depended on its sorption capacity with respect to the substrate. In contrast to homogeneous catalysts, usage of solid PCPs may allow selectivity due to porous structure and simplify separation of product. PMID

  8. Nucleus accumbens response to gains in reputation for the self relative to gains for others predicts social media use

    PubMed Central

    Meshi, Dar; Morawetz, Carmen; Heekeren, Hauke R.

    2013-01-01

    Our reputation is important to us; we've experienced natural selection to care about our reputation. Recently, the neural processing of gains in reputation (positive social feedback concerning one's character) has been shown to occur in the human ventral striatum. It is still unclear, however, how individual differences in the processing of gains in reputation may lead to individual differences in real-world behavior. For example, in the real-world, one way that people currently maintain their reputation is by using social media websites, like Facebook. Furthermore, Facebook use consists of a social comparison component, where users observe others' behavior and can compare it to their own. Therefore, we hypothesized a relationship between the way the brain processes specifically self-relevant gains in reputation and one's degree of Facebook use. We recorded functional neuroimaging data while participants received gains in reputation, observed the gains in reputation of another person, or received monetary reward. We demonstrate that across participants, when responding to gains in reputation for the self, relative to observing gains for others, reward-related activity in the left nucleus accumbens predicts Facebook use. However, nucleus accumbens activity in response to monetary reward did not predict Facebook use. Finally, a control step-wise regression analysis showed that Facebook use primarily explains our results in the nucleus accumbens. Overall, our results demonstrate how individual sensitivity of the nucleus accumbens to the receipt of self-relevant social information leads to differences in real-world behavior. PMID:24009567

  9. Nucleus accumbens response to gains in reputation for the self relative to gains for others predicts social media use.

    PubMed

    Meshi, Dar; Morawetz, Carmen; Heekeren, Hauke R

    2013-01-01

    Our reputation is important to us; we've experienced natural selection to care about our reputation. Recently, the neural processing of gains in reputation (positive social feedback concerning one's character) has been shown to occur in the human ventral striatum. It is still unclear, however, how individual differences in the processing of gains in reputation may lead to individual differences in real-world behavior. For example, in the real-world, one way that people currently maintain their reputation is by using social media websites, like Facebook. Furthermore, Facebook use consists of a social comparison component, where users observe others' behavior and can compare it to their own. Therefore, we hypothesized a relationship between the way the brain processes specifically self-relevant gains in reputation and one's degree of Facebook use. We recorded functional neuroimaging data while participants received gains in reputation, observed the gains in reputation of another person, or received monetary reward. We demonstrate that across participants, when responding to gains in reputation for the self, relative to observing gains for others, reward-related activity in the left nucleus accumbens predicts Facebook use. However, nucleus accumbens activity in response to monetary reward did not predict Facebook use. Finally, a control step-wise regression analysis showed that Facebook use primarily explains our results in the nucleus accumbens. Overall, our results demonstrate how individual sensitivity of the nucleus accumbens to the receipt of self-relevant social information leads to differences in real-world behavior.

  10. All-optical switching of localized surface plasmon resonance in single gold nanosandwich using GeSbTe film as an active medium

    SciTech Connect

    Hira, T.; Homma, T.; Uchiyama, T.; Kuwamura, K.; Kihara, Y.; Saiki, T.

    2015-01-19

    Localized surface plasmon resonance (LSPR) switching was investigated in a Au/GeSbTe/Au nanosandwich as a key active element for plasmonic integrated circuits and devices. Near-infrared single-particle spectroscopy was conducted to examine the interaction of a Au nanorod (AuNR) and Au film, between which a GeSbTe layer was incorporated as an active phase-change media. Numerical calculation revealed that hybridized modes of the AuNR and Au film exhibit a significant change of scattering intensity with the phase change. In particular, the antisymmetric (magnetic resonance) mode can be modulated effectively by the extinction coefficient of GST, as well as its refractive index. Experimental demonstration of the switching operation was performed by alternate irradiation with a picosecond pulsed laser for amorphization and a continuous wave laser for crystallization. Repeatable modulation was obtained by monitoring the scattering light around the LSPR peak at λ = 1070 nm.

  11. A Technology-Mediated Behavioral Weight Gain Prevention Intervention for College Students: Controlled, Quasi-Experimental Study

    PubMed Central

    Monroe, Courtney M; Turner-McGrievy, Gabrielle; Sundstrom, Beth; Larsen, Chelsea; Magradey, Karen; Wilcox, Sara; Brandt, Heather M

    2016-01-01

    Background Both men and women are vulnerable to weight gain during the college years, and this phenomenon is linked to an increased risk of several chronic diseases and mortality. Technology represents an attractive medium for the delivery of weight control interventions focused on college students, given its reach and appeal among this population. However, few technology-mediated weight gain prevention interventions have been evaluated for college students. Objective This study examined a new technology-based, social media-facilitated weight gain prevention intervention for college students. Methods Undergraduates (n =58) in two sections of a public university course were allocated to either a behavioral weight gain prevention intervention (Healthy Weight, HW; N=29) or a human papillomavirus (HPV) vaccination awareness intervention (control; N=29). All students were enrolled, regardless of initial body weight or expressed interest in weight management. The interventions delivered 8 lessons via electronic newsletters and Facebook postings over 9 weeks, which were designed to foster social support and introduce relevant educational content. The HW intervention targeted behavioral strategies to prevent weight gain and provided participants with a Wi-Fi-enabled scale and an electronic physical activity tracker to facilitate weight regulation. A repeated-measures analysis of variance was conducted to examine within- and between-group differences in measures of self-reported weight control practices and objectively measured weight. Use of each intervention medium and device was objectively tracked, and intervention satisfaction measures were obtained. Results Students remained weight stable (HW: −0.48+1.9 kg; control: −0.45+1.4 kg), with no significant difference between groups over 9 weeks (P =.94). However, HW students reported a significantly greater increase in the number of appropriate weight control strategies than did controls (2.1+4.5 vs −1

  12. A comparative investigation of metal-support interactions on the catalytic activity of Pt nanoparticles for ethanol oxidation in alkaline medium

    NASA Astrophysics Data System (ADS)

    Godoi, Denis R. M.; Villullas, Hebe M.; Zhu, Fu-Chun; Jiang, Yan-Xia; Sun, Shi-Gang; Guo, Junsong; Sun, Lili; Chen, Rongrong

    2016-04-01

    The effects of interactions of Pt nanoparticles with hybrid supports on reactivity towards ethanol oxidation in alkaline solution are investigated. Studies involve catalysts with identical Pt nanoparticles on six hybrid supports containing carbon powder and transition metal oxides (TiO2, ZrO2, SnO2, CeO2, MoO3 and WO3). In situ X-ray absorption spectroscopy (XAS) results evidence that metal-support interactions produce changes in the Pt 5d band vacancy, which appears to determine the catalytic activity. The highest and lowest activities are observed for Pt nanoparticles on hybrid supports containing TiO2 and CeO2, respectively. Further studies are presented for these two catalysts. In situ FTIR reflection spectroscopy measurements, taken using both multi-stepped FTIR spectroscopy (MS-FTIR) and single potential alteration FTIR spectroscopy (SPA-FTIR), evidence that the main product of ethanol oxidation is acetate, although signals attributed to carbonate and CO2 indicate some differences in CO2 production. Fuel cell performances of these catalysts, tested in a 4.5 cm2 single cell at different temperatures (40-90 °C) show good agreement with data obtained by electrochemical techniques. Results of this comprehensive study point out the possibility of compensating a reduction of noble metal load with an increase in activity promoted by interactions between metallic nanoparticles and a support.

  13. Risk Insights Gained from Fire Incidents

    SciTech Connect

    Kazarians, Mardy; Nowlen, Steven P.

    1999-06-10

    There now exist close to 20 years of history in the application of Probabilistic Risk Assessment (PRA) for the analysis of fire risk at nuclear power plants. The current methods are based on various assumptions regarding fire phenomena, the impact of fire on equipment and operator response, and the overall progression of a fire event from initiation through final resolution. Over this same time period, a number of significant fire incidents have occurred at nuclear power plants around the world. Insights gained from US experience have been used in US studies as the statistical basis for establishing fire initiation frequencies both as a function of the plant area and the initiating fire source.To a lesser extent, the fire experience has also been used to assess the general severity and duration of fires. However, aside from these statistical analyses, the incidents have rarely been scrutinized in detail to verify the underlying assumptions of fire PRAs. This paper discusses an effort, under which a set of fire incidents are being reviewed in order to gain insights directly relevant to the methods, data, and assumptions that form the basis for current fire PRAs. The paper focuses on the objectives of the effort, the specific fire events being reviews methodology, and anticipated follow-on activities.

  14. Gain control in the sonar of odontocetes.

    PubMed

    Ya Supin, Alexander; Nachtigall, Paul E

    2013-06-01

    The sonar of odontocetes processes echo-signals within a wide range of echo levels. The level of echoes varies widely by tens of decibels depending on the level of the emitted sonar pulse, the target strength, the distance to the target, and the sound absorption by the water media. The auditory system of odontocetes must be capable of effective perception, analysis, and discrimination of echo-signals within all this variability. The sonar of odontocetes has several mechanisms to compensate for the echo-level variation (gain control). To date, several mechanisms of the biosonar gain control have been revealed in odontocetes: (1) adjustment of emitted sonar pulse levels (the longer the distance to the target, the higher the level of the emitted pulse), (2) short-term variation of hearing sensitivity based on forward masking of the echo by the preceding self-heard emitted pulse and subsequent release from the masking, and (3) active long-term control of hearing sensitivity. Recent investigations with the use of the auditory evoked-potential technique have demonstrated that these mechanisms effectively minimize the variation of the response to the echo when either the emitted sonar pulse level, or the target distance, or both vary within a wide range. A short review of these data is presented herein.

  15. Steering, splitting, and cloning of an optical beam in a coherently driven Raman gain system

    NASA Astrophysics Data System (ADS)

    Verma, Onkar N.; Dey, Tarak N.

    2015-01-01

    We propose an all-optical antiwaveguide mechanism for steering, splitting, and cloning of an optical beam without diffraction. We use a spatially inhomogeneous pump beam to create an antiwaveguide structure in a Doppler broadened N -type four-level Raman gain medium for a copropagating weak probe beam. We show that a transverse modulated index of refraction and gain due to the spatially dependent pump beam hold the keys to steering, splitting, and cloning of an optical beam. We have also shown that an additional control field permits the propagation of an optical beam through an otherwise gain medium without diffraction and instability. We further discuss how finesse of the cloned images can be increased by changing the detuning of the control field. We arrive at similar results by using homogeneously broadened gain media at higher density.

  16. Effects of Collaborative Group Composition and Inquiry Instruction on Reasoning Gains and Achievement in Undergraduate Biology

    PubMed Central

    Jensen, Jamie Lee; Lawson, Anton

    2011-01-01

    This study compared the effectiveness of collaborative group composition and instructional method on reasoning gains and achievement in college biology. Based on initial student reasoning ability (i.e., low, medium, or high), students were assigned to either homogeneous or heterogeneous collaborative groups within either inquiry or didactic instruction. Achievement and reasoning gains were assessed at the end of the semester. Inquiry instruction, as a whole, led to significantly greater gains in reasoning ability and achievement. Inquiry instruction also led to greater confidence and more positive attitudes toward collaboration. Low-reasoning students made significantly greater reasoning gains within inquiry instruction when grouped with other low reasoners than when grouped with either medium or high reasoners. Results are consistent with equilibration theory, supporting the idea that students benefit from the opportunity for self-regulation without the guidance or direction of a more capable peer. PMID:21364101

  17. Electrocatalytic oxidation of small organic molecules in acid medium: enhancement of activity of noble metal nanoparticles and their alloys by supporting or modifying them with metal oxides

    PubMed Central

    Kulesza, Pawel J.; Pieta, Izabela S.; Rutkowska, Iwona A.; Wadas, Anna; Marks, Diana; Klak, Karolina; Stobinski, Leszek; Cox, James A.

    2013-01-01

    Different approaches to enhancement of electrocatalytic activity of noble metal nanoparticles during oxidation of small organic molecules (namely potential fuels for low-temperature fuel cells such as methanol, ethanol and formic acid) are described. A physical approach to the increase of activity of catalytic nanoparticles (e.g. platinum or palladium) involves nanostructuring to obtain highly dispersed systems of high surface area. Recently, the feasibility of enhancing activity of noble metal systems through the formation of bimetallic (e.g. PtRu, PtSn, and PdAu) or even more complex (e.g. PtRuW, PtRuSn) alloys has been demonstrated. In addition to possible changes in the electronic properties of alloys, specific interactions between metals as well as chemical reactivity of the added components have been postulated. We address and emphasize here the possibility of utilization of noble metal and alloyed nanoparticles supported on robust but reactive high surface area metal oxides (e.g. WO3, MoO3, TiO2, ZrO2, V2O5, and CeO2) in oxidative electrocatalysis. This paper concerns the way in which certain inorganic oxides and oxo species can act effectively as supports for noble metal nanoparticles or their alloys during electrocatalytic oxidation of hydrogen and representative organic fuels. Among important issues are possible changes in the morphology and dispersion, as well as specific interactions leading to the improved chemisorptive and catalytic properties in addition to the feasibility of long time operation of the discussed systems. PMID:24443590

  18. Electrocatalytic oxidation of small organic molecules in acid medium: enhancement of activity of noble metal nanoparticles and their alloys by supporting or modifying them with metal oxides.

    PubMed

    Kulesza, Pawel J; Pieta, Izabela S; Rutkowska, Iwona A; Wadas, Anna; Marks, Diana; Klak, Karolina; Stobinski, Leszek; Cox, James A

    2013-11-01

    Different approaches to enhancement of electrocatalytic activity of noble metal nanoparticles during oxidation of small organic molecules (namely potential fuels for low-temperature fuel cells such as methanol, ethanol and formic acid) are described. A physical approach to the increase of activity of catalytic nanoparticles (e.g. platinum or palladium) involves nanostructuring to obtain highly dispersed systems of high surface area. Recently, the feasibility of enhancing activity of noble metal systems through the formation of bimetallic (e.g. PtRu, PtSn, and PdAu) or even more complex (e.g. PtRuW, PtRuSn) alloys has been demonstrated. In addition to possible changes in the electronic properties of alloys, specific interactions between metals as well as chemical reactivity of the added components have been postulated. We address and emphasize here the possibility of utilization of noble metal and alloyed nanoparticles supported on robust but reactive high surface area metal oxides (e.g. WO3, MoO3, TiO2, ZrO2, V2O5, and CeO2) in oxidative electrocatalysis. This paper concerns the way in which certain inorganic oxides and oxo species can act effectively as supports for noble metal nanoparticles or their alloys during electrocatalytic oxidation of hydrogen and representative organic fuels. Among important issues are possible changes in the morphology and dispersion, as well as specific interactions leading to the improved chemisorptive and catalytic properties in addition to the feasibility of long time operation of the discussed systems.

  19. Effect of solvent viscosity on the anisotropy of distribution of excited centers in an active medium of a dye laser at a pump power near the threshold value

    SciTech Connect

    Yartsev, A.I.; Sechkarev, A.V.

    1995-03-01

    Dependences of the anisotropy of the distribution of excited centers (A) in rhodamine 6G and 6-aminophenolenon solutions in organic solvents of different viscosity are studied. Relying on the character of the dependence of A on the viscosity, the conclusion is made that it is possible to employ a relation similar to the Levshin-Perrin formula for polarized luminescence in the threshold excitation mode. Experimental data are used to calculate angles between absorption and emission dipoles of electron auxochrome groups of molecules for the dyes under investigation and to estimate the effective volume of activator molecules for the ethanol solution of rhodamine 6G. 6 refs., 1 fig.

  20. Ionic liquid-induced all-α to α + β conformational transition in cytochrome c with improved peroxidase activity in aqueous medium.

    PubMed

    Bharmoria, Pankaj; Trivedi, Tushar J; Pabbathi, Ashok; Samanta, Anunay; Kumar, Arvind

    2015-04-21

    Choline dioctylsulfosuccinate [Cho][AOT] (a surface active ionic liquid) has been found to induce all-α to α + β conformational transition in the secondary structure of enzyme cytochrome c (Cyt c) with an enhanced peroxidase activity in its aqueous vesicular phase at pH 7.0. [Cho][AOT] interacted with Cyt c distinctly at three critical concentrations (aggregation C1, saturation C2 and vesicular C3) as detected from isothermal titration calorimetric analysis. Oxidation of heme iron was observed from the disappearance of the Q band in the UV-vis spectra of Cyt c upon [Cho][AOT] binding above C3. Circular dichroism analysis (CD) has shown the loss in both the secondary (190-240 nm) and tertiary (250-300 nm) structure of Cyt c in the monomeric regime until C1, followed by their stabilization until the pre-vesicular regime (C1 → C3). Loss in both the secondary and tertiary structure has been observed in the post-vesicular regime with the change in Cyt c conformation from all-α to α + β which is similar to the conformational changes of Cyt c upon binding with mitochondrial membrane (Biochemistry 1998, 37, 6402-6409), thus citing the potential utility of [Cho][AOT] membranes as an artificial analog for in vitro bio-mimicking. Fluorescence correlation spectroscopy (FCS) measurements confirm the unfolding of Cyt c in the vesicular phase. Dynamic light scattering experiments have shown the contraction of [Cho][AOT] vesicles upon Cyt c binding driven by electrostatic interactions observed by charge neutralization from zeta potential measurements. [Cho][AOT] has been found to enhance the peroxidase activity of Cyt c with maximum activity at C3, observed using 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt as the substrate in the presence of hydrogen peroxide. This result shows the relevance of tuning ionic liquids to surfactants for bio-mimicking of specific membrane protein-lipid interactions. PMID:25798458

  1. The Local Interstellar Medium

    NASA Astrophysics Data System (ADS)

    Ferlet, Roger

    Substantial progress in the field of the Local Interstellar Medium has been largely due to recent launches of space missions, mostly in the UV and X-ray domains, but also to ground-based observations, mainly in high resolution spectroscopy. However, a clear gap seems to remain between the wealth of new data and the theoretical understanding. This paper gives an overview of some observational aspects, with no attempt of completeness or doing justice to all the people involved in the field. As progress rarely evolves in straight paths, we can expect that our present picture of the solar system surroundings is not definitive.

  2. Microscopic analysis of non-equilibrium dynamics in the semiconductor-laser gain medium

    SciTech Connect

    Hader, J.; Moloney, J. V.; Koch, S. W.

    2014-04-14

    Fully microscopic many-body calculations are used to analyze the carrier dynamics in situations where a strong sub-picosecond pulse interacts with an inverted semiconductor quantum well. Electron-electron and electron-phonon scatterings are calculated on a second Born-Markov level. Intra-subband scatterings on a scale of tens of femtoseconds are shown to quickly re-fill the kinetic holes created in the carrier distributions during the pulse amplification. Even for sub-100 fs pulses, this significantly influences the pulse amplification as well as its spectral dependence. Interband scatterings on a few picosecond timescale limit the possibly achievable repetition rate in pulsed semiconductor lasers.

  3. Passively Mode-Locked Femtosecond Laser with Disordered Crystal Nd:CGA as Gain Medium

    NASA Astrophysics Data System (ADS)

    He, Kun-Na; Liu, Jia-Xing; Tian, Wen-Long; Shen, Zhong-Wei; Xu, Xiao-Dong; Wang, Zhao-Hua; Li, De-Hua; Xu, Jun; Di, Ju-Qing; Xia, Chang-Tai; Wei, Zhi-Yi

    2016-09-01

    Not Available Supported by the National Key Basic Research Program of China under Grant No 2013CB922402, the International Joint Research Program, and the National Natural Science Foundation of China under Grant Nos 61210017 and 11434016.

  4. Double-control coherent absorption and transparency in a six-level optical gain medium

    NASA Astrophysics Data System (ADS)

    Ghosh, Saswata; Mandal, Swapan

    2011-10-01

    The application of two coupling/pump fields to an M-type six-level atomic system in order to manipulate the probe response is suggested in this paper. With the inverted population condition the analytical formulation of the probe response is examined under the purview of coupling field-induced double-control quantum interference effects at different detunings. In particular, we report electromagnetically induced absorption and transparency via controlling the driving contribution of two coupling fields on different probe transitions. These driving contributions of the two coupling fields rely on lower-level hyperfine coherence, detuning and strength.

  5. Yb:FAP and related materials, laser gain medium comprising same, and laser systems using same

    DOEpatents

    Krupke, William F.; Payne, Stephen A.; Chase, Lloyd L.; Smith, Larry K.

    1994-01-01

    An ytterbium doped laser material remarkably superior to all others, including Yb:YAG, comprises Ytterbium doped apatite (Yb:Ca.sub.5 (PO.sub.4).sub.3 F) or Yb:FAP, or ytterbium doped crystals that are structurally related to FAP. The new laser material is used in laser systems pumped by diode pump sources having an output near 0.905 microns or 0.98 microns, such as InGaAs and AlInGaAs, or other narrowband pump sources near 0.905 microns or 0.98 microns. The laser systems are operated in either the conventional or ground state depletion mode.

  6. Yb:FAP and related materials, laser gain medium comprising same, and laser systems using same

    DOEpatents

    Krupke, W.F.; Payne, S.A.; Chase, L.L.; Smith, L.K.

    1994-01-18

    An ytterbium doped laser material remarkably superior to all others, including Yb:YAG, comprises ytterbium doped apatite (Yb:Ca[sub 5](PO[sub 4])[sub 3]F) or Yb:FAP, or ytterbium doped crystals that are structurally related to FAP. The new laser material is used in laser systems pumped by diode pump sources having an output near 0.905 microns or 0.98 microns, such as InGaAs and AlInGaAs, or other narrowband pump sources near 0.905 microns or 0.98 microns. The laser systems are operated in either the conventional or ground state depletion mode. 9 figures.

  7. Gain assisted nanocomposite multilayers with near zero permittivity modulus at visible frequencies

    NASA Astrophysics Data System (ADS)

    Rizza, Carlo; Di Falco, Andrea; Ciattoni, Alessandro

    2011-11-01

    We have fabricated a nano-laminate by alternating metal and gain medium layers, the gain dielectric consisting of a polymer incorporating optically pumped dye molecules. From standard reflection-transmission experiments, we show that, at a visible wavelength, both the real and the imaginary parts of the permittivity ɛ∥ attain very small values and we measure, at λ = 604 nm, |ɛ∥|=0.04 which is 21.5% smaller than its value in the absence of optical pumping. Our investigation thus proves that a medium with a permittivity with very small modulus, a key condition promising efficient subwavelength optical steering, can be actually synthesized.

  8. System gain function calculation for acoustic arrays using ray optical methods

    NASA Astrophysics Data System (ADS)

    Schmid, O.; Vonwinterfeld, C.

    1980-11-01

    The gain function of an acoustic antenna array is calculated with respect to waves, propagating from a point source into an homogeneous medium (water) with a sinusoidally varying surface of known phase statistics, treating antenna and environment as one system. An asymptotic solution (high frequency approximation) is developed. For distances of several wavelengths between the array and the surface of the medium, the propagation mechanism is described by a geometrical theory of diffraction applied to scalar waves. The gain function of the antenna together with the reflecting surface is obtained from the cross correlations of the resulting sound fields of each antenna element.

  9. Forward ramp & low gain antenna

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Mars Pathfinder's forward rover ramp can be seen successfully unfurled in this color image, taken by the Imager for Mars Pathfinder (IMP) on Sol 3. This ramp was not used for the deployment of the microrover Sojourner, which occurred at the end of Sol 2. When this image was taken, Sojourner was still latched to one of the lander's petals, waiting for the command sequence that would execute its descent off of the lander's petal. The image helped Pathfinder scientists determine whether to deploy the rover using the forward or backward ramps and the nature of the first rover traverse. The metallic object at the lower part of the image is the lander's low-gain antenna. The square at the end of the ramp is one of the spacecraft's magnetic targets. Dust that accumulates on the magnetic targets will later be examined by Sojourner's Alpha Proton X-Ray Spectrometer instrument for chemical analysis. At center, a lander petal is visible.

    spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

  10. Achieving yield gains in wheat.

    PubMed

    Reynolds, Matthew; Foulkes, John; Furbank, Robert; Griffiths, Simon; King, Julie; Murchie, Erik; Parry, Martin; Slafer, Gustavo

    2012-10-01

    Wheat provides 20% of calories and protein consumed by humans. Recent genetic gains are <1% per annum (p.a.), insufficient to meet future demand. The Wheat Yield Consortium brings expertise in photosynthesis, crop adaptation and genetics to a common breeding platform. Theory suggest radiation use efficiency (RUE) of wheat could be increased ~50%; strategies include modifying specificity, catalytic rate and regulation of Rubisco, up-regulating Calvin cycle enzymes, introducing chloroplast CO(2) concentrating mechanisms, optimizing light and N distribution of canopies while minimizing photoinhibition, and increasing spike photosynthesis. Maximum yield expression will also require dynamic optimization of source: sink so that dry matter partitioning to reproductive structures is not at the cost of the roots, stems and leaves needed to maintain physiological and structural integrity. Crop development should favour spike fertility to maximize harvest index so phenology must be tailored to different photoperiods, and sensitivity to unpredictable weather must be modulated to reduce conservative responses that reduce harvest index. Strategic crossing of complementary physiological traits will be augmented with wide crossing, while genome-wide selection and high throughput phenotyping and genotyping will increase efficiency of progeny screening. To ensure investment in breeding achieves agronomic impact, sustainable crop management must also be promoted through crop improvement networks.

  11. Nonlinearity-induced PT-symmetry without material gain

    NASA Astrophysics Data System (ADS)

    Miri, Mohammad-Ali; Alù, Andrea

    2016-06-01

    Parity-time symmetry has raised a great deal of attention in optics in recent years, yet its application has been so far hindered by the stringent requirements on coherent gain balanced with loss. In this paper, we show that the conditions to enable parity and time symmetry can be simultaneously satisfied for a pair of modes with mixed frequencies interacting in a nonlinear medium, without requiring the presence of material gain. First, we consider a guided wave structure with second order nonlinearity and we derive the PT-symmetric Hamiltonian that governs the interaction of two waves of mixed frequencies when accompanied by a high intensity pump beam at the sum frequency. We also extend the results to an array of coupled nonlinear waveguide channels. It is shown that the evolution dynamics of the low-frequency waves is associated with a periodic PT-symmetric lattice while the phase of the pump beams can be utilized as a control parameter to modify the gain and loss distribution, thus realizing different PT lattices by design. Our results suggest that nonlinear wave mixing processes can form a rich platform to realize PT-symmetric Hamiltonians of arbitrary dimensions in optical systems, without requiring material gain.

  12. STADAN antenna gain calibration using radio stars

    NASA Technical Reports Server (NTRS)

    Taylor, R. E.

    1972-01-01

    An antenna gain measurement method was developed which utilizes a signal emitted from a radio star to determine absolute antenna gain at 136 MHz and 400 MHz for antennas in the STADAN network. An error analysis of the radio star method shows that the overall standard deviation uncertainty in antenna gain is + or - 0.6 db (1 sigma).

  13. Determination of optimal gains for constrained controllers

    SciTech Connect

    Kwan, C.M.; Mestha, L.K.

    1993-08-01

    In this report, we consider the determination of optimal gains, with respect to a certain performance index, for state feedback controllers where some elements in the gain matrix are constrained to be zero. Two iterative schemes for systematically finding the constrained gain matrix are presented. An example is included to demonstrate the procedures.

  14. DENSE MEDIUM CYCLONE OPTIMIZATON

    SciTech Connect

    Gerald H. Luttrell; Chris J. Barbee; Peter J. Bethell; Chris J. Wood

    2005-06-30

    Dense medium cyclones (DMCs) are known to be efficient, high-tonnage devices suitable for upgrading particles in the 50 to 0.5 mm size range. This versatile separator, which uses centrifugal forces to enhance the separation of fine particles that cannot be upgraded in static dense medium separators, can be found in most modern coal plants and in a variety of mineral plants treating iron ore, dolomite, diamonds, potash and lead-zinc ores. Due to the high tonnage, a small increase in DMC efficiency can have a large impact on plant profitability. Unfortunately, the knowledge base required to properly design and operate DMCs has been seriously eroded during the past several decades. In an attempt to correct this problem, a set of engineering tools have been developed to allow producers to improve the efficiency of their DMC circuits. These tools include (1) low-cost density tracers that can be used by plant operators to rapidly assess DMC performance, (2) mathematical process models that can be used to predict the influence of changes in operating and design variables on DMC performance, and (3) an expert advisor system that provides plant operators with a user-friendly interface for evaluating, optimizing and trouble-shooting DMC circuits. The field data required to develop these tools was collected by conducting detailed sampling and evaluation programs at several industrial plant sites. These data were used to demonstrate the technical, economic and environmental benefits that can be realized through the application of these engineering tools.

  15. Gestational weight gain among Hispanic women.

    PubMed

    Sangi-Haghpeykar, Haleh; Lam, Kim; Raine, Susan P

    2014-01-01

    To describe gestational weight gain among Hispanic women and to examine psychological, social, and cultural contexts affecting weight gain. A total of 282 Hispanic women were surveyed post-partum before leaving the hospital. Women were queried about their prepregnancy weight and weight gained during pregnancy. Adequacy of gestational weight gain was based on guidelines set by the Institute of Medicine in 2009. Independent risk factors for excessive or insufficient weight gain were examined by logistic regression. Most women were unmarried (59 %), with a mean age of 28.4 ± 6.6 years and an average weight gain of 27.9 ± 13.3 lbs. Approximately 45 % of women had gained too much, 32 % too little, and only 24 % had an adequate amount of weight gain. The mean birth weight was 7.3, 7.9, and 6.8 lbs among the adequate, excessive, and insufficient weight gain groups. Among women who exercised before pregnancy, two-thirds continued to do so during pregnancy; the mean gestational weight gain of those who continued was lower than those who stopped (26.8 vs. 31.4 lbs, p = 0.04). Independent risk factors for excessive weight gain were being unmarried, U.S. born, higher prepregnancy body mass index, and having indifferent or negative views about weight gain. Independent risk factors for insufficient weight gain were low levels of support and late initiation of prenatal care. Depression, stress, and a woman's or her partner's happiness regarding pregnancy were unrelated to weight gain. The results of this study can be used by prenatal programs to identify Hispanic women at risk for excessive or insufficient gestational weight gain.

  16. Silver migration from silver-modified activated carbon applied as a water filtration medium in classic cartridges of jug filter systems.

    PubMed

    Garboś, S; Swięcicka, D

    2012-01-01

    A comprehensive study was undertaken in order to examine the possible adverse effect of jug filter systems (JFSs) on the quality of filtered water taking into account the released amounts of silver (Ag) into the filtered test water. Nine brands of JFSs (A-I) were investigated according to BS 8427:2004 using a validated ICP/MS method. Essential modification of BS 8427:2004 within the domain of the composite sample preparation was proposed and applied during the tests. The established grand mean concentrations of released Ag from A-H classic cartridges (containing Ag-modified activated carbon and ion exchange resins) and I classic cartridge (containing non-modified activated carbon and ion exchange resin) installed in corresponding JFSs were in the range of 2.6-13.1 µg l⁻¹ and lower than 0.014 µg l⁻¹, respectively. These values were applied for the estimation of the daily intakes of Ag connected with the consumption of water filtered using JFSs (ranging from < 0.0004 to 0.374 µg kg⁻¹ day⁻¹). After taking into account the grand mean concentrations of Ag established during the whole cycle of exploitation for nine JFSs and on the basis of available toxicological data for this element, no long-term risk for human health with respect to appearance of argyria (a condition caused by improper exposure to the Ag or Ag compounds) could be expected (the Hazard Quotient indices estimated as ratios of the daily intakes to the reference dose of Ag were equal or lower than 0.075). Ag-modified activated carbon is not included in the positive list of the authorised substances of the European Commission Regulation (EU) No. 10/2011. Additionally, this material has not been approved by European Food Safety Authority (EFSA). A part of water filtered by JFSs can be directly consumed as drinking water and additionally the remaining water can be applied for the preparation of food products (drinks, soups, etc.). In both cases the quality of water has to fulfil

  17. Silver migration from silver-modified activated carbon applied as a water filtration medium in classic cartridges of jug filter systems.

    PubMed

    Garboś, S; Swięcicka, D

    2012-01-01

    A comprehensive study was undertaken in order to examine the possible adverse effect of jug filter systems (JFSs) on the quality of filtered water taking into account the released amounts of silver (Ag) into the filtered test water. Nine brands of JFSs (A-I) were investigated according to BS 8427:2004 using a validated ICP/MS method. Essential modification of BS 8427:2004 within the domain of the composite sample preparation was proposed and applied during the tests. The established grand mean concentrations of released Ag from A-H classic cartridges (containing Ag-modified activated carbon and ion exchange resins) and I classic cartridge (containing non-modified activated carbon and ion exchange resin) installed in corresponding JFSs were in the range of 2.6-13.1 µg l⁻¹ and lower than 0.014 µg l⁻¹, respectively. These values were applied for the estimation of the daily intakes of Ag connected with the consumption of water filtered using JFSs (ranging from < 0.0004 to 0.374 µg kg⁻¹ day⁻¹). After taking into account the grand mean concentrations of Ag established during the whole cycle of exploitation for nine JFSs and on the basis of available toxicological data for this element, no long-term risk for human health with respect to appearance of argyria (a condition caused by improper exposure to the Ag or Ag compounds) could be expected (the Hazard Quotient indices estimated as ratios of the daily intakes to the reference dose of Ag were equal or lower than 0.075). Ag-modified activated carbon is not included in the positive list of the authorised substances of the European Commission Regulation (EU) No. 10/2011. Additionally, this material has not been approved by European Food Safety Authority (EFSA). A part of water filtered by JFSs can be directly consumed as drinking water and additionally the remaining water can be applied for the preparation of food products (drinks, soups, etc.). In both cases the quality of water has to fulfil

  18. Small signal gain in DPAL systems

    NASA Astrophysics Data System (ADS)

    Galbally-Kinney, Kristin L.; Maser, Daniel L.; Kessler, William J.; Rawlins, Wilson T.; Davis, Steven J.

    2011-03-01

    In this paper we describe a platform for small signal gain measurements for alkali atom laser systems based on the DPAL excitation method. We present initial results that clearly show the transition from absorption on the alkali atom D1 lines in Cs and Rb to optical transparency and positive gain. The achievement of optical gain is critically dependent upon alkali cell conditions and collision partners. We also present the first spatially resolved gain measurements in a DPAL system. The small signal gain methods described will be valuable tools for power scaling of these laser systems.

  19. Clean method for the synthesis of reduced graphene oxide-supported PtPd alloys with high electrocatalytic activity for ethanol oxidation in alkaline medium.

    PubMed

    Ren, Fangfang; Wang, Huiwen; Zhai, Chunyang; Zhu, Mingshan; Yue, Ruirui; Du, Yukou; Yang, Ping; Xu, Jingkun; Lu, Wensheng

    2014-03-12

    In this article, a clean method for the synthesis of PtPd/reduced graphene oxide (RGO) catalysts with different Pt/Pd ratios is reported in which no additional components such as external energy (e.g., high temperature or high pressure), surfactants, or stabilizing agents are required. The obtained catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), induced coupled plasma atomic emission spectroscopy (ICP-AES), and electrochemical measurements. The HRTEM measurements showed that all of the metallic nanoparticles (NPs) exhibited well-defined crystalline structures. The composition of these Pt-Pd/RGO catalysts can be easily controlled by adjusting the molar ratio of the Pt and Pd precursors. Both cyclic voltammetry (CV) and chronoamperometry (CA) results demonstrate that bimetallic PtPd catalysts have superior catalytic activity for the ethanol oxidation reaction compared to the monometallic Pt or Pd catalyst, with the best performance found with the PtPd (1:3)/RGO catalyst. The present study may open a new approach for the synthesis of PtPd alloy catalysts, which is expected to have promising applications in fuel cells.

  20. Observation of polarized gain from aligned colloidal nanorods

    NASA Astrophysics Data System (ADS)

    Gao, Yuan; Ta, Van Duong; Zhao, Xin; Wang, Yue; Chen, Rui; Mutlugun, Evren; Fong, Kah Ee; Tan, Swee Tiam; Dang, Cuong; Sun, Xiao Wei; Sun, Handong; Demir, Hilmi Volkan

    2015-04-01

    In recent years, colloidal semiconductor nanorods have attracted great interest for polarized spontaneous emission. However, their polarized gain has not been possible to achieve so far. In this work we show the highly polarized stimulated emission from the densely packed ensembles of core-seeded nanorods in a cylindrical cavity. Here CdSe/CdS dot-in-rods were coated and aligned on the inner wall of a capillary tube, providing optical feedback for the nanorod gain medium. Results show that the polarized gain originates intrinsically from the aligned nanorods and not from the cavity and that the optical anisotropy of the nanorod ensemble was amplified with the capillary tube, resulting in highly polarized whispering gallery mode lasing. The highly polarized emission and lasing, together with easy fabrication and flexible incorporation, make this microlaser a promising candidate for important color conversion and enrichment applications including liquid crystal display backlighting and laser lighting.In recent years, colloidal semiconductor nanorods have attracted great interest for polarized spontaneous emission. However, their polarized gain has not been possible to achieve so far. In this work we show the highly polarized stimulated emission from the densely packed ensembles of core-seeded nanorods in a cylindrical cavity. Here CdSe/CdS dot-in-rods were coated and aligned on the inner wall of a capillary tube, providing optical feedback for the nanorod gain medium. Results show that the polarized gain originates intrinsically from the aligned nanorods and not from the cavity and that the optical anisotropy of the nanorod ensemble was amplified with the capillary tube, resulting in highly polarized whispering gallery mode lasing. The highly polarized emission and lasing, together with easy fabrication and flexible incorporation, make this microlaser a promising candidate for important color conversion and enrichment applications including liquid crystal display

  1. [Dependence of the intracellular concentrations of univalent ions and hydrogenase activity on the salt composition and pH of the medium in the haloalkaliphilic sulfate-reducing bacterium Desulfonatronum thiodismutans].

    PubMed

    Soboleva, G S; Dulov, L E; Pusheva, M A

    2007-01-01

    It has been shown that the intracellular concentrations of Na+, K+, and Cl- ions in Desulfonatronum thiodismutans depend on the extracellular concentration of Na' ions. An increase in the extracellular concentration of Na+ results in the accumulation of K+ ions in cells, which points to the possibility that these ions perform an osmoprotective function. When the concentration of the NaCI added to the medium was increased to 4%, the concentration gradient of Cl- ions changed insignificantly. It was found that D. thiodismutans contains two forms of hydrogenase--periplasmic and cytoplasmic. Both enzymes are capable of functioning in solutions with high ionic force; however they exhibit different sensitivities to Na+, K+, and Li+ salts and pH. The enzymes were found to be resistant to high concentrations of Na+ and K+ chlorides and Na+ bicarbonate. The cytoplasmic hydrogenase differed significantly from the periplasmic one in having much higher salt tolerance and lower pH optimum. The activity of these enzymes depended on the nature of both the cationic and anionic components of the salts. For instance, the inhibitory effect of NaCl was less pronounced than that of LiCl, whereas Na+ and Li+ sulfates inhibited the activity of both hydrogenase types to an equal degree. The highest activity of these enzymes was observed at low Na+ concentrations, close to those typical of cells growing at optimal salt concentrations. PMID:17410870

  2. Antipsychotic induced weight gain in schizophrenia:mechanisms and management.

    PubMed

    Rege, Sanil

    2008-05-01

    The aim of the present paper was to describe the mechanisms and management of antipsychotic-induced weight gain in schizophrenia patients. A comprehensive literature review of all available articles on the mechanisms and management of antipsychotic-induced weight gain was done by searching databases PsychINFO and PubMed. A summary of the available guidelines for monitoring of antipsychotic-induced weight gain and metabolic syndrome is also provided. There has been a substantial increase in the number of studies investigating the mechanisms and management of antipsychotic-induced weight gain after 2002. These include advances in the understanding of pharmacogenomics of weight gain and several randomized controlled trials (RCTs) evaluating pharmacological and psychological treatments to promote weight loss. The most effective strategy for prevention of weight gain is the choice of antipsychotic medication with low weight gain potential. In individuals with established weight gain and metabolic issues, switching to an antipsychotic agent with lower weight gain potential and/or lifestyle modifications with physical activity are most effective in promoting weight loss. Pharmacological agents such as orlistat and sibutramine are effective in general obesity but have not been sufficiently evaluated in antipsychotic-induced weight gain. The case to prescribe routine pharmacological treatment to promote weight loss is weak. Long-term, pragmatic studies are required to inform clinical practice. Weight gain in schizophrenia is associated with significant physical and psychological morbidity. Achieving an optimal trade-off between effectiveness and side-effects of antipsychotic agents, although difficult, is achievable. This should be based on three main principles: (i) a shared decision-making model between the patient, clinician and carer(s) when choosing an antipsychotic; (ii) a commitment to baseline and follow-up monitoring with explicit identification of the responsible

  3. Gain engineering for all-optical microwave and high speed pulse generation in mode-locked fiber lasers

    NASA Astrophysics Data System (ADS)

    Li, Fangxin; Helmy, Amr S.

    2014-03-01

    Pulsed sources based on approaches that employ only photonic components and no RF components will be discussed in this talk. Several technologies have been explored to generate actively mode-locked sources using electronically driven fiber ring cavities. However, for these sources the pulse repetition rate is usually limited by the bandwidth of the intracavity modulator. Filtering of highly-stable low repetition rate optical combs utilizing cavities such as Fabry-Perot etalons can be used to overcome this limitation. This scheme is not flexible as it requires highly precise control of ultrahigh finesse etalons which limits the repetition rate to the free spectral range of the filter. Pulsed sources based on semiconductor devices offer many advantages, including large gain bandwidth, rapid tunability, long-term stability. In this work we introduce a novel, simple method to generate optical clock with wavelength tunability using two continuous wave (CW) lasers. The lasers are injected into a conventional SOAs-based fiber ring laser. The beating signal generated by these two lasers causes the modulation of the SOA gain saturation inside the cavity. Thus, the SOA provides gain and functions as the modulator as well as the gain medium. When the lasing mode inside the cavity is amplified, it also results in gain-induced four wave mixing. The proposed technique is particularly versatile, overcoming the bandwidth limitation of other techniques, which require RF sources. Moreover, this technique provides the possibility for hybrid integration as it is comprised of semiconductor chips that can be heterogeneously integrated on a Si platform.

  4. Discharge-pumped cw gas lasers utilizing ``dressed-atom'' gain media

    NASA Astrophysics Data System (ADS)

    Sorokin, P. P.; Glownia, J. H.; Hodgson, R. T.

    2005-05-01

    The possibility of realizing an efficient gaseous laser-beam-generating medium that utilizes Λ -type coherently phased (i.e., “dressed”) atoms for the active laser species, but that does not inherently require the use of external laser beams for pumping, is explored. Specifically, it is investigated if multiphoton stimulated hyper-Raman scattering (SHRS) processes driven by fluorescence radiation generated in a continuous electrical discharge present within the vapor-containing cell could produce continuous-wave (cw) optical gain at the Λ -atom resonance frequencies ωo and ωo' . It is deduced that such gain could result from n -photon (n⩾4) SHRS processes only if absorption of fluorescence pump light occurs in the first three transitions of the n -photon sequence representing the process unit step. Estimates of the amount of optical gain that could be produced in such a system indicate that it should be sufficient to allow multiwatt cw laser operation to occur on one set of Λ transitions connecting levels in a “double- Λ ” structure, with the pump light being discharge-produced fluorescence centered about the transitions of the other Λ pair. However, to initiate operation of such a device would require injection into the laser optical cavity of intense “starter” laser pulses at both lasing frequencies. What should be an optimal experimental configuration for determining feasibility of the proposed laser device is described. In the suggested configuration, Cs-atom 6S1/2-6P1/2 transitions form the double- Λ structure.

  5. The influence of gain nonlinearities on distortion in semiconductor lasers

    NASA Astrophysics Data System (ADS)

    Lysak, Vladimir V.; Schatz, Richard; Shulika, Aleksey V.; Sukhoivanov, Igor A.; Kjebon, O.

    2004-09-01

    The semiconductor laser is commonly used as a light source in fiber-optical telecommunication systems. In order to send as much information as possible in a short time, it is important that the laser has a large modulation bandwidth, i.e., the turn-on and turn-off time should be as short as possible. In analogue fiber optic systems for transmission of radio or television signals, it is also important that the light from the laser increases linearly with driving current even at high modulation frequencies. Otherwise, the transmitted signal will become distorted. The modulation bandwidth and the modulation distortion are dependent both on the laser structure and the gain characteristics of the active material. One of the most useful approaches for the time-domain description of the response of optoelectronic devices is the so-called "rate equation model," which has been widely used to describe laser performance. Commonly, laser models with simple gain expressions are used for simulation of laser dynamics. In these models the small-signal dynamic parameters like the differential gain and gain saturation parameter are extracted from modulation response measurements. However, we show that in order to correctly calculate distortion, an accurate model of the dependence of gain on carrier density, n, and photon density, s, is needed. Commonly used gain models, fitted to give exactly the same modulation response can give significantly different distortion behavior.

  6. Radiation cooling and gain calculation for C VI 182 A line in C/Se plasma

    SciTech Connect

    Nam, C.H.; Valeo, E.; Suckewer, S.; Feldman, U.

    1986-04-01

    A model is developed which is capable of describing the evolution of gain resulting from both rapid radiative and expansion cooling of a recombining, freely expanding plasma. It is demonstrated for the particular case of a carbon/selenium plasma that the cooling rate which leads to optimal gain can be achieved by adjusting the admixture of an efficiently radiating material (selenium) in the gain medium (carbon). Comparison is made to a recent observation of gain in a recent NRL/Rochester experiment with carbon/selenium plasma for the n = 3 ..-->.. 2 transition in C VI occurring at 182 A. The predicted maximum gain is approx.10 cm/sup -1/, as compared to observation of 2 to 3 cm/sup -1/.

  7. Pharmacological management of atypical antipsychotic-induced weight gain.

    PubMed

    Baptista, Trino; ElFakih, Yamily; Uzcátegui, Euderruh; Sandia, Ignacio; Tálamo, Eduardo; Araujo de Baptista, Enma; Beaulieu, Serge

    2008-01-01

    Excessive bodyweight gain was reported during the 1950s as an adverse effect of typical antipsychotic drug treatment, but the magnitude of bodyweight gain was found to be higher with the atypical antipsychotic drugs that were introduced after 1990. Clozapine and olanzapine produce the greatest bodyweight gain, ziprasidone and aripiprazole have a neutral influence, and quetiapine and risperidone cause an intermediate effect. In the CATIE study, the percentage of patients with bodyweight gain of >7% compared with baseline differed significantly between the antipsychotic drugs, i.e. 30%, 16%, 14%, 12% and 7% for olanzapine, quetiapine, risperidone, perphenazine (a typical antipsychotic) and ziprasidone, respectively (p<0.001). Appetite stimulation is probably a key cause of bodyweight gain, but genetic polymorphisms modify the bodyweight response during treatment with atypical antipsychotics. In addition to nutritional advice, programmed physical activity, cognitive-behavioural training and atypical antipsychotic switching, pharmacological adjunctive treatments have been assessed to counteract excessive bodyweight gain. In some clinical trials, nizatidine, amantadine, reboxetine, topiramate, sibutramine and metformin proved effective in preventing or reversing atypical antipsychotic-induced bodyweight gain; however, the results are inconclusive since few randomized, placebo-controlled clinical trials have been conducted. Indeed, most studies were short-term trials without adequate statistical power and, in the case of metformin, nizatidine and sibutramine, the results are contradictory. The tolerability profile of these agents is adequate. More studies are needed before formal recommendations on the use of these drugs can be made. Meanwhile, clinicians are advised to use any of these adjunctive treatments according to their individual pharmacological and tolerability profiles, and the patient's personal and family history of bodyweight gain and metabolic dysfunction.

  8. Optical antenna gain. I - Transmitting antennas

    NASA Technical Reports Server (NTRS)

    Klein, B. J.; Degnan, J. J.

    1974-01-01

    The gain of centrally obscured optical transmitting antennas is analyzed in detail. The calculations, resulting in near- and far-field antenna gain patterns, assume a circular antenna illuminated by a laser operating in the TEM-00 mode. A simple polynomial equation is derived for matching the incident source distribution to a general antenna configuration for maximum on-axis gain. An interpretation of the resultant gain curves allows a number of auxiliary design curves to be drawn that display the losses in antenna gain due to pointing errors and the cone angle of the beam in the far field as a function of antenna aperture size and its central obscuration. The results are presented in a series of graphs that allow the rapid and accurate evaluation of the antenna gain which may then be substituted into the conventional range equation.

  9. Personalized health planning with integrative health coaching to reduce obesity risk among women gaining excess weight during pregnancy.

    PubMed

    Yang, Nancy Y; Wroth, Shelley; Parham, Catherine; Strait, Melva; Simmons, Leigh Ann

    2013-07-01

    Health coaching is an emerging behavioral intervention to improve outcomes in chronic disease management and prevention; however, no studies have investigated its utility in postpartum women who have gained excess weight during pregnancy. A 32-year-old primigravida woman who was overweight at conception and gained 23 lbs more than Institute of Medicine recommendations for her pre-pregnancy body mass index participated in a 6-month personalized health planning with integrative health coaching (PHPIHC) intervention. The intervention included a baseline health risk assessment review with a healthcare provider and eight biweekly, 30-minute telephonic health coaching sessions. The participant demonstrated improvement in physical activity, energy expenditure, knowledge, and confidence to engage in healthpromoting behaviors. Although the participant did not reach the target weight by completion of the health coaching sessions, follow up 8 months later indicated she achieved the target goal (within 5% of prepregnancy weight). This case report suggests that PHP-IHC can support postpartum women in returning to pre-pregnancy weight after gaining excess gestational weight. Future research and clinical trials are needed to determine the best timing, length, and medium (online, in-person, telephonic) of PHP-IHC for postpartum women.

  10. Edge cladding gain media according to IL-11317

    SciTech Connect

    Soules, T

    2005-02-10

    In this patent application we wish to claim the following approach to ameliorating spontaneous amplified emission (ASE) that occurs in a laser amplifier slab. There are two important elements of our approach. We wish to claim the application of both together but not either one alone. (1) The first element of the invention is to roughen the edge surfaces of the amplifier slab. A rough surface with random planar features larger than the wavelength of light will reflect and refract incident light rays at angles different than the median plane of the surface. The rough surface can then be characterized by two parameters. First there is a distribution of heights about the zero mean plane of the surface. If normal this distribution is characterized by a standard deviation. The second parameter is the correlation distance that describes how close together on average are the peaks and valleys. The ratio of these two numbers determines the spread of light reflected off the surface of the edge of the slab. (2) The second element in our invention is to bond the roughened edges of the gain medium to an ASE absorbing media using a suitable bonding agent. In order for the ASE to leave the gain medium crystal there must be minimal reflection and maximum transmission at the interface. This requires having a near match of the index of refraction of the bonding medium and the amplifier slab material at the wavelength of the ASE. Further if the index of refraction of the bonding agent is less than that of the amplifier there will be some total internal reflection even if the surface is roughened. The index of refraction of GGG is {approx} 1.92 and that of YAG is {approx} 1.84. There are no suitable bonding agents with indices of refraction this high.

  11. Catalytic activity of ruthenium(III) on the oxidation of an anticholinergic drug-atropine sulfate monohydrate by copper(III) periodate complex in aqueous alkaline medium - decarboxylation and free radical mechanism.

    PubMed

    Byadagi, Kirthi S; Nandibewoor, Sharanappa T; Chimatadar, Shivamurti A

    2013-01-01

    Atropine sulfate monohydrate (ASM) is an anticholinergic drug, having a wide spectrum of activity. Hence, the kinetics of oxidation of ASM by diperiodatocuperate (DPC) in the presence of micro (10-6) amounts of Ru(III) catalyst has been investigated spectrophotometrically in aqueous alkaline medium at I = 0.50 mol dm-3. The reaction between DPC and ASM exhibits 1:2 stoichiometry (ASM:DPC) i. e., one mole of ASM require two moles of DPC to give products. The main oxidation products were confirmed by spectral studies. The reaction is first order with respect to [DPC] and [Ru(III)], while the order with respect to [ASM] and [OH-] was less than unity. The rates decreased with increase in periodate concentration. The reaction rates revealed that Ru(III) catalyzed reaction was about seven-fold faster than the uncatalyzed reaction. The catalytic constant (KC) was also determined at different temperatures. A plausible mechanism is proposed. The activation parameters with respect to slow step of the mechanism were calculated and the thermodynamic quantities were also determined. Kinetic experiments suggest that [Cu(H2IO6)(H2O)2] is the reactive Cu(III) species and [Ru(H2O)5OH]2+ is the reactive Ru(III) species. PMID:24169716

  12. Proprioceptive feedback determines visuomotor gain in Drosophila

    PubMed Central

    Bartussek, Jan; Lehmann, Fritz-Olaf

    2016-01-01

    Multisensory integration is a prerequisite for effective locomotor control in most animals. Especially, the impressive aerial performance of insects relies on rapid and precise integration of multiple sensory modalities that provide feedback on different time scales. In flies, continuous visual signalling from the compound eyes is fused with phasic proprioceptive feedback to ensure precise neural activation of wing steering muscles (WSM) within narrow temporal phase bands of the stroke cycle. This phase-locked activation relies on mechanoreceptors distributed over wings and gyroscopic halteres. Here we investigate visual steering performance of tethered flying fruit flies with reduced haltere and wing feedback signalling. Using a flight simulator, we evaluated visual object fixation behaviour, optomotor altitude control and saccadic escape reflexes. The behavioural assays show an antagonistic effect of wing and haltere signalling on visuomotor gain during flight. Compared with controls, suppression of haltere feedback attenuates while suppression of wing feedback enhances the animal’s wing steering range. Our results suggest that the generation of motor commands owing to visual perception is dynamically controlled by proprioception. We outline a potential physiological mechanism based on the biomechanical properties of WSM and sensory integration processes at the level of motoneurons. Collectively, the findings contribute to our general understanding how moving animals integrate sensory information with dynamically changing temporal structure. PMID:26909184

  13. Gestational weight gain trajectories in primary care

    PubMed Central

    Piccinini-Vallis, Helena; Lee-Baggley, Dayna; Stewart, Moira; Ryan, Bridget

    2016-01-01

    Objective To identify gestational weight gain trajectories, stratified by prepregnancy body mass index (BMI), of women with singleton pregnancies who received prenatal care in a primary care setting, and to compare these trajectories with the 2009 Institute of Medicine gestational weight gain recommendations. Design Retrospective cohort study. Setting Halifax, NS. Participants Women who received prenatal care at the Dalhousie Family Medicine clinics in Halifax from 2009 to 2013. Main outcome measures For each prenatal visit, gestational age and weight measurements were obtained. Multilevel modeling was used to analyze the gestational weight gain trajectories. The upper limit of the guideline-recommended weekly gestational weight gain was compared with the 95% CI of the observed mean weekly gestational weight gain for each prepregnancy BMI category. Results A total of 280 women were included in the analyses. There was a significant interaction between prepregnancy BMI category and gestational weight gain over time (P < .001), with gestational weight gain being significantly lower among women with prepregnancy BMI of 30.0 kg/m2 or greater compared with those with BMI of 18.5 to less than 25.0 kg/m2 and 25.0 to less than 30.0 kg/m2. When comparing women’s weight gain with the recommendations, women with prepregnancy BMI of 25.0 to less than 30.0 kg/m2 had the most guideline discordance, deviating from the weight gain recommendations at 20 weeks’ gestation. Conclusion These results are relevant and of benefit to women and clinicians wishing to address excess gestational weight gain, and to researchers and policy makers developing interventions aimed at curbing gestational weight gain in primary care. Although our results showed women with prepregnancy BMI of 25.0 to less than 30.0 kg/m2 gained the most excess, guideline-discordant weight, interventions should target all women planning or experiencing a pregnancy.

  14. Measurement of Antenna Bore-Sight Gain

    NASA Technical Reports Server (NTRS)

    Fortinberry, Jarrod; Shumpert, Thomas

    2016-01-01

    The absolute or free-field gain of a simple antenna can be approximated using standard antenna theory formulae or for a more accurate prediction, numerical methods may be employed to solve for antenna parameters including gain. Both of these methods will result in relatively reasonable estimates but in practice antenna gain is usually verified and documented via measurements and calibration. In this paper, a relatively simple and low-cost, yet effective means of determining the bore-sight free-field gain of a VHF/UHF antenna is proposed by using the Brewster angle relationship.

  15. Error margin for antenna gain measurements

    NASA Technical Reports Server (NTRS)

    Cable, V.

    2002-01-01

    The specification of measured antenna gain is incomplete without knowing the error of the measurement. Also, unless gain is measured many times for a single antenna or over many identical antennas, the uncertainty or error in a single measurement is only an estimate. In this paper, we will examine in detail a typical error budget for common antenna gain measurements. We will also compute the gain uncertainty for a specific UHF horn test that was recently performed on the Jet Propulsion Laboratory (JPL) antenna range. The paper concludes with comments on these results and how they compare with the 'unofficial' JPL range standard of +/- ?.

  16. Very high gain Nd:YLF amplifiers

    SciTech Connect

    Knights, M.G.; Thomas, M.D.; Chicklis, E.P.; Rines, G.A.; Seka, W.

    1988-05-01

    The authors report on high gain Nd:YLF rod amplifiers in which single-pass, small signal gains of over 1700 have been obtained along with stored energy densitiesgreater than or equal to0.4J/cm/sup 3/. The ability of Nd:YLF amplifiers to support such gains is a result of high parasitic oscillation thresholds, due primarily to the low refractive index of the material. These results suggest that Nd:YLF is an excellent candidate for amplifiers where high specific stored energies and/or very high gains are required.

  17. VEGF mRNA in adipocytes increase with rebound weight-gain after diet-restriction.

    PubMed

    Hattori, Kanae; Sumi, Toshiyuki; Yasui, Tomoyo; Morimura, Mina; Nobeyama, Hiroyuki; Okamoto, Eri; Noriyuki, Maiko; Honda, Kenichi; Kiyama, Hiroshi; Ishiko, Osamu

    2004-03-01

    The mechanism of rebound body weight-gain after a restricted-diet state is unclear. We investigated the expression of angiogenic factors in human adipocytes with a changing nutritional state in culture medium, and attempted to ascertain the mechanisms involved in rebound weight-gain. Adipocytes were divided into three groups; the first group (control group) was cultured in medium with 10% fetal calf serum (FCS), the second (DR3% group) was cultured in medium with 3% FCS, and the third (DR6% group) was cultured in medium with 6% FCS. After being cultured for 48 h, each was next cultured with 12% FCS for a further 48 h. When made to change from a low nutrition state to a higher one, adipocytes changed from hypotrophic to hypertrophic. Simultaneously, vascular endothelial growth factor (VEGF) in the culture medium increased significantly. When investigated immunohistochemically, the expression of VEGF was similarly shown in the cytoplasm of adipocytes. The same tendency with the same quantity of mRNA was shown by RT-PCR. These results show that VEGF produced and secreted from adipocytes increases, when the cultivation state of adipocytes is changed from a low nutritional state to a higher one. VEGF produced and secreted from adipocytes may be related to rebound weight-gain.

  18. Interstellar medium simulations

    NASA Astrophysics Data System (ADS)

    Breitschwerdt, D.; de Avillez, M. A.; Feige, J.; Dettbarn, C.

    2012-06-01

    In this review we critically assess numerical simulations of the interstellar medium (ISM), and argue that 3D high resolution calculations are the most promising method to determine the structure of the interstellar gas and follow its evolution well into the nonlinear regime. Based on a Riemann solver adaptive mesh refinement code, we present a model, which fulfills the basic requirements of running it sufficiently long in order to erase memory effects of the initial conditions, set up a disk-halo fountain flow cycle, for converging solutions with increasing mesh refinement. We obtain the following results: (i) in a supernova driven ISM, high Reynolds number turbulence generates structures on all scales, (ii) the volume filling factor of the hot gas is substantially reduced due to the fountain flow, (iii) gas clouds are transient shock compressed layers, (iv) more than half of the gas mass resides in thermally unstable regimes, (v) O VI is distributed in patchy mixing layers, with the derived column densities being in agreement with FUSE and Copernicus observations, (vi) the electron density distribution up to distances of 8 kpc in the disk is consistent with pulsar dispersion measure observations, provided that the electron and ionization structure are not in equilibrium, (vii) the interstellar cooling function depends both on space and time (and not only on temperature and metallicity), (viii) the Local Bubble has been produced by 14-20 supernovae about 14 Myr ago, exploding in a moving group on its path through the local ISM, (ix) the nearest supernova explosion to Earth occurred 2.2 {×} 106 yr ago at a distance of {˜} 85 pc, in agreement with measurements of the radionuclide 60Fe found in the ferromanganese crust on the ocean floor.

  19. Active-mirror-laser-amplifier thermal management with tunable helium pressure at cryogenic temperatures.

    PubMed

    Lucianetti, Antonio; Albach, Daniel; Chanteloup, Jean-Christophe

    2011-06-20

    We illustrate the benefits of a thin, low pressure helium cell for efficient and safe heat removal in cryogenically-cooled active mirror laser amplifiers operating in the [100 J-1 kJ]/[1-10 Hz] range. A homogeneous gain medium temperature distribution averaging 160 K is obtained with a sub-mm helium-filled gap between the gain medium and a copper plate at 77 K. A significant degree of flexibility for tuning the temperature in the amplifier can be achieved by varying the pressure of the helium gas in the 10(2) to 10(5) Pa range. PMID:21716519

  20. Controlled synthesis of La{sub 1−x}Sr{sub x}CrO{sub 3} nanoparticles by hydrothermal method with nonionic surfactant and their ORR activity in alkaline medium

    SciTech Connect

    Choi, Bo Hyun; Park, Shin-Ae; Park, Bong Kyu; Chun, Ho Hwan; Kim, Yong-Tae

    2013-10-15

    Graphical abstract: We demonstrate that Sr-doped LaCrO{sub 3} nanoparticles were successfully prepared by the hydrothermal synthesis method using the nonionic surfactant Triton X-100 and the applicability of La{sub 1−x}Sr{sub x}CrO{sub 3} to oxygen reduction reaction (ORR) electrocatalysis in an alkaline medium. Compared with the nanoparticles synthesized by the coprecipitation method, they showed enhanced ORR activity. - Highlights: • Sr-doped LaCrO{sub 3} nanoparticles were successfully prepared by the hydrothermal method using the nonionic surfactant. • Homogeneously shaped and sized Sr-doped LaCrO{sub 3} nanoparticles were readily obtained. • Compared with the nanoparticles synthesized by the coprecipitation method, they showed an enhanced ORR activity. • The main origin was revealed to be the decreased particle size due to the nonionic surfactant. - Abstract: Sr-doped LaCrO{sub 3} nanoparticles were prepared by the hydrothermal method with the nonionic surfactant Triton X-100 followed by heat treatment at 1000 °C for 10 h. The obtained perovskite nanoparticles had smaller particle size (about 100 nm) and more uniform size distribution than those synthesized by the conventional coprecipitation method. On the other hand, it was identified with the material simulation that the electronic structure change by Sr doping was negligible, because the initially unfilled e{sub g}-band was not affected by the p-type doping. Finally, the perovskite nanoparticles synthesized by hydrothermal method showed much higher ORR activity by over 200% at 0.8 V vs. RHE than those by coprecipitation method.

  1. LiNi1/3Co1/3Mn1/3O2 nanoplates with {010} active planes exposing prepared in polyol medium as a high-performance cathode for Li-ion battery.

    PubMed

    Li, Jili; Yao, Ruimin; Cao, Chuanbao

    2014-04-01

    As we know, Li(+)-ion transport in layered LiNi1/3Co1/3Mn1/3O2 (NCM) is through two-dimensional channels parallel to the Li(+)-ion layers that are indexed as {010} active planes. In this paper, NCM nanoplates with exposed {010} active facets are synthesized in a polyol medium (ethylene glycol) and characterized by XRD, XPS, SEM, and HR-TEM. In addition, the effects of reaction conditions on the morphologies, structures and electrochemical performances are also evaluated. The results show that more {010} facets can be exposed with the thickness of NCM nanoplates increasing which can lead to more channels for Li(+)-ion migration. However, when the annealing temperatures exceed 900 °C, many new crystal planes grow along the thickness direction covering the {010} facets. In all of the NCM nanoplates obtained at different conditions, the NCM nanoplates calcined at 850 °C for 12 h (NCM-850-12H) display a high initial discharge capacity of 207.6 mAh g(-1) at 0.1 C (1 C = 200 mA g(-1)) between 2.5 and 4.5 V higher than most of NCM materials as cathodes for lithium ion batteries. The discharge capacities of NCM-850-12H are 169.8, 160.5, and 149.3 mAh g(-1) at 2, 5, and 7 C, respectively, illustrating the excellent rate capability. The superior electrochemical performance of NCM-850-12H cathode can be attributed to more {010} active planes exposure.

  2. Correcting the Normalized Gain for Guessing

    ERIC Educational Resources Information Center

    Stewart, John; Stewart, Gay

    2010-01-01

    The normalized gain, "g", has been an important tool for the characterization of conceptual improvement in physics courses since its use in Hake's extensive study on conceptual learning in introductory physics. The normalized gain is calculated from the score on a pre-test administered before instruction and a post-test administered after…

  3. Sudden Gains During Therapy of Social Phobia

    PubMed Central

    Hofmann, Stefan G.; Schulz, Stefan M.; Meuret, Alicia E.; Moscovitch, David A.; Suvak, Michael

    2007-01-01

    The present study investigated the phenomenon of sudden gains in 107 participants with social phobia (social anxiety disorder) who received either cognitive–behavioral group therapy or exposure group therapy without explicit cognitive interventions, which primarily used public speaking situations as exposure tasks. Twenty-two out of 967 session-to-session intervals met criteria for sudden gains, which most frequently occurred in Session 5. Individuals with sudden gains showed similar improvements in the 2 treatment groups. Although cognitive–behavioral therapy was associated with more cognitive changes than exposure therapy, cognitive changes did not precede sudden gains. In general, the results of this study question the clinical significance of sudden gains in social phobia treatment. PMID:16881776

  4. College weight gain and behavior transitions: male and female differences.

    PubMed

    Cluskey, Mary; Grobe, Deana

    2009-02-01

    College-student weight gain has been well-documented. However, little is known about the sex differences in weight gain and related behaviors during the transition to college. A repeated-measure study design was used to reveal measured weight changes from October to December 2005 among male and female college students. Three-hundred seventy-nine college students (60% males) participated in both weight assessments and revealed weight gains occurring early in college. Weight gains were found to be of greater incidence and magnitude among college males in the study. More than 25% of both college males and females gained >2.3 kg body weight in an 8-week period. Females starting the study with overweight and obese body mass index (calculated as kg/m(2)) scores were less likely to gain than either obese or overweight body mass index males or low to healthy body mass index students of both sexes. A life-course perspective was used to analyze focus group discussions conducted among students who participated in the weight assessments and explored their perceptions of the transition in eating and exercise behaviors when coming to college. Students described struggles in adapting healthful eating and exercise behaviors to college life. Comments indicated that while college student activity levels differed from the past, there was consistent agreement that eating healthful diets was perceived to be a greater challenge in the transition to college. Male students were less concerned about weight and used fewer strategies to control weight gain than females. More work is needed to understand the transition of behaviors and in developing healthful lifestyles during college.

  5. The value of exercising control over monetary gains and losses.

    PubMed

    Leotti, Lauren A; Delgado, Mauricio R

    2014-02-01

    Using functional MRI, we examined how the affective experience of choice, the means by which individuals exercise control, is modulated by the valence of potential outcomes (gains, losses). When trials involved potential gains, participants reported liking cues predicting a choice opportunity better than cues predicting no choice opportunity--an effect that corresponded with blood-oxygen-level-dependent (BOLD) increases in ventral striatum (VS) activity. Surprisingly, no differences were observed between choice and no-choice cues when participants anticipated potential losses. Individual differences in subjective choice preference in the loss condition, however, corresponded to choice-related BOLD activity in VS. We conducted a second experiment to examine whether monetary losses were perceived differently in the context of simultaneous gains. When losses occurred in the absence of gains, participants showed an increased affective experience of choice--they reported greater liking of choice than no-choice trials, and VS activity was greater for choice than for no-choice cues. Collectively, the findings suggest that the affective experience of choice involves reward-processing circuitry when people anticipate appetitive and aversive outcomes, but the choice experience may be sensitive to context and individual differences. PMID:24390827

  6. New medium licensed for campylobacter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A medium, “Campy-Cefex”, has been licensed by the ARS Office of Technology Transfer with Becton Dickinson (No. 1412-002) and Neogen (No. 1412-001) based on patent No. 5,891,709, “Campy-Cefex Selective and Differential Medium for Campylobacter” by Dr. Norman Stern of the Poultry Microbiological Safet...

  7. Recent results of the GAINS test flight

    NASA Astrophysics Data System (ADS)

    Girz, C.

    A demonstration flight of the Global Atmosphere-ocean IN-situ System (GAINS) Prototype III balloon is scheduled to occur in early summer 2002. The 18-m diameter PIII superpressure balloon, built by GSSL, Inc., will float a 135-kg payload at 16 km. Performance of the SpectraTM envelope will be assessed over two day-night cycles. The payload consists of line-of-sight communications for transmitting GPS position, and monitored parameters on balloon and payload state and the internal and external thermal environments. Primary termination is by radio command with several independent backup termination systems. Safe operation of the balloon is ensured by an onboard transponder that keeps the balloon under active air traffic control. The balloon is tracked by an aircraft that will record communications from the balloon and instigate termination of the flight. Mobile ground stations positioned at the launch and recovery locations will also be capable of recording and terminating the flight. A suite of trajectory forecast tools has been developed based on radiosondes and winds from numerical weather models. A GPS surface reflection experiment for determining ocean surface winds will be tested on this platform. Physical and electronic integration of the radio and mechanical systems was completed over the last two years. Data and videos from the June flight will be presented.

  8. Gain Control Network Conditions in Early Sensory Coding

    PubMed Central

    Serrano, Eduardo; Nowotny, Thomas; Levi, Rafael; Smith, Brian H.; Huerta, Ramón

    2013-01-01

    Gain control is essential for the proper function of any sensory system. However, the precise mechanisms for achieving effective gain control in the brain are unknown. Based on our understanding of the existence and strength of connections in the insect olfactory system, we analyze the conditions that lead to controlled gain in a randomly connected network of excitatory and inhibitory neurons. We consider two scenarios for the variation of input into the system. In the first case, the intensity of the sensory input controls the input currents to a fixed proportion of neurons of the excitatory and inhibitory populations. In the second case, increasing intensity of the sensory stimulus will both, recruit an increasing number of neurons that receive input and change the input current that they receive. Using a mean field approximation for the network activity we derive relationships between the parameters of the network that ensure that the overall level of activity of the excitatory population remains unchanged for increasing intensity of the external stimulation. We find that, first, the main parameters that regulate network gain are the probabilities of connections from the inhibitory population to the excitatory population and of the connections within the inhibitory population. Second, we show that strict gain control is not achievable in a random network in the second case, when the input recruits an increasing number of neurons. Finally, we confirm that the gain control conditions derived from the mean field approximation are valid in simulations of firing rate models and Hodgkin-Huxley conductance based models. PMID:23874176

  9. High gain holmium-doped fibre amplifiers.

    PubMed

    Simakov, Nikita; Li, Zhihong; Jung, Yongmin; Daniel, Jae M O; Barua, Pranabesh; Shardlow, Peter C; Liang, Sijing; Sahu, Jayanta K; Hemming, Alexander; Clarkson, W Andrew; Alam, Shaif-Ul; Richardson, David J

    2016-06-27

    We investigate the operation of holmium-doped fibre amplifiers (HDFAs) in the 2.1 µm spectral region. For the first time we demonstrate a diode-pumped HDFA. This amplifier provides a peak gain of 25 dB at 2040 nm with a 15 dB gain window spanning the wavelength range 2030 - 2100 nm with an external noise figure (NF) of 4-6 dB. We also compare the operation of HDFAs when pumped at 1950 nm and 2008 nm. The 1950 nm pumped HDFA provides 41 dB peak gain at 2060 nm with 15 dB of gain spanning the wavelength range 2050 - 2120 nm and an external NF of 7-10 dB. By pumping at the longer wavelength of 2008 nm the gain bandwidth of the amplifier is shifted to longer wavelengths and using this architecture a HDFA was demonstrated with a peak gain of 39 dB at 2090 nm and 15 dB of gain spanning the wavelength range 2050 - 2150 nm. The external NF over this wavelength range was 8-14 dB. PMID:27410557

  10. The Circumgalactic Medium of Quasars

    NASA Astrophysics Data System (ADS)

    Hennawi, Joe

    2014-07-01

    I will argue that observations of the diffuse gas in the outskirts of quasar host galaxies, or the so called circumgalactic medium, are essential for understanding how luminous quasars evolve in a cosmological context. Such observations also provide a fruitful comparison to theory, because hydrodynamics at moderate overdensities is much easier to simulate than the complicated processes which trigger quasar activity. A novel technique will be introduced, whereby a foreground quasar can be studied in absorption against a background quasar, resolving scales as small as 30 kpc. This experiment reveals a rich absorption spectrum which contains a wealth of information about the physical conditions of diffuse gas around quasars. Hydrodynamical simulations of the massive dark matter halos which host luminous quasars under predict the amount of cool gas observed in quasar environs by a large factor, challenging our understanding of how massive galaxies form. I will also discuss a very sensitive search for Ly-alpha emission from the same gas which we study in absorption.

  11. High-Frequency Power Gain in the Mammalian Cochlea

    NASA Astrophysics Data System (ADS)

    Maoiléidigh, Dáibhid Ó.; Hudspeth, A. J.

    2011-11-01

    Amplification in the mammalian inner ear is thought to result from a nonlinear active process known as the cochlear amplifier. Although there is much evidence that outer hair cells (OHCs) play a central role in the cochlear amplifier, the mechanism of amplification remains uncertain. In non-mammalian ears hair bundles can perform mechanical work and account for the active process in vitro, yet in the mammalian cochlea membrane-based electromotility is required for amplification in vivo. A key issue is how OHCs conduct mechanical power amplification at high frequencies. We present a physical model of a segment of the mammalian cochlea that can amplify the power of external signals. In this representation both electromotility and active hair-bundle motility are required for mechanical power gain at high frequencies. We demonstrate how the endocochlear potential, the OHC resting potential, Ca2+ gradients, and ATP-fueled myosin motors serve as the energy sources underlying mechanical power gain in the cochlear amplifier.

  12. Provider advice about pregnancy weight gain and adequacy of weight gain.

    PubMed

    Ferrari, Renée M; Siega-Riz, Anna Maria

    2013-02-01

    To explore the association between health care provider advice about weight gain and gestational weight gain. Using data from a prospective cohort study, we explored the association between provider advice about weight gain in pregnancy with weight gain adequacy among 1,454 pregnant women. Provider advice was measured by maternal self-report at 27-30 weeks' gestation. Linear and Poisson regression were used to explore associations. Seventy-eight percent of the women gained outside current recommendations. Fifty-one percent reported receiving weight gain advice from a health care provider. Adjusted Generalized Linear Model (GLM) estimates showed weak effect of provider advice on inadequate or excessive gain (Relative Risk (RR) 0.96, 95% CI 0.74, 1.26 for inadequate gain and RR 1.01, 95% CI 0.97, 1.06 for excessive gain). There is a need for more women to hear about their targeted weight gains during pregnancy and the present advice that exists does little to influence actual gains. Further studies are warranted to find better strategies for providers to motivate their patients to gain weight within the appropriate ranges.

  13. TCAD simulation of Low Gain Avalanche Detectors

    NASA Astrophysics Data System (ADS)

    Dalal, Ranjeet; Jain, Geetika; Bhardwaj, Ashutosh; Ranjan, Kirti

    2016-11-01

    In the present work, detailed simulation using Technology Computer Aided Design (TCAD) tool, Silvaco for non-irradiated and irradiated LGAD (Low Gain Avalanche Detector) devices has been carried out. The effects of different design parameters and proton irradiation on LGAD operation are discussed in detail. An already published effective two trap bulk damage model is used to simulate the radiation damage without implementing any acceptor removal term. The TCAD simulation for irradiated LGAD devices produce decreasing gain with increasing fluence, similar to the measurement results. The space charge density and electric field distribution are used to illustrate the possible reasons for the degradation of gain of the irradiated LGAD devices.

  14. A High Gain, Composite Nd:YVO4/SiC Thin Disk Amplifier

    NASA Astrophysics Data System (ADS)

    Newburgh, G. A.; Dubinskii, Mark

    2014-06-01

    We have demonstrated a new form of Nd:YVO4 amplifier operating at 1064 nm based on a 800 µm thick Nd:YVO4 gain layer bonded to a 4H-SiC prism. The amplifier was tested in the `master oscillator - power amplifier' (MOPA) configuration, where both the seed source and the single pass amplifier were operated in a quasi-continuous wave (Q-CW) regime: pulse duration 500 µs, pulse repetition frequency (PRF) - 100 Hz. The Nd:YVO4gain element was pumped by a 808 nm laser diode bar stack to amplify seed inputs in the power range of 1 to 55 W with a gains of 4 to 2.6, respectively, with 25% optical-to-optical extraction efficiency. The temperature distribution of the gain medium was measured under operational conditions using thermography.

  15. Optical properties of nanowire metamaterials with gain

    NASA Astrophysics Data System (ADS)

    Lima, Joaquim; Adam, Jost; Rego, Davi; Esquerre, Vitaly; Bordo, Vladimir

    2016-11-01

    The transmittance, reflectance and absorption of a nanowire metamaterial with optical gain are numerically simulated and investigated. It is assumed that the metamaterial is represented by aligned silver nanowires embedded into a semiconductor matrix, made of either silicon or gallium phosphide. The gain in the matrix is modeled by adding a negative imaginary part to the dielectric function of the semiconductor. It is found that the optical coefficients of the metamaterial depend on the gain magnitude in a non-trivial way: they can both increase and decrease with gain depending on the lattice constant of the metamaterial. This peculiar behavior is explained by the field redistribution between the lossy metal nanowires and the amplifying matrix material. These findings are significant for a proper design of nanowire metamaterials with low optical losses for diverse applications.

  16. Organic Causes of Weight Gain and Obesity

    MedlinePlus

    ... Issues Listen Español Text Size Email Print Share Organic Causes of Weight Gain and Obesity Page Content ... as children, before they became heavy. Still other organic factors partly determine which kids can eat anything ...

  17. Loss of HDAC-Mediated Repression and Gain of NF-κB Activation Underlie Cytokine Induction in ARID1A- and PIK3CA-Mutation-Driven Ovarian Cancer.

    PubMed

    Kim, Minchul; Lu, Falong; Zhang, Yi

    2016-09-27

    ARID1A is frequently mutated in ovarian clear cell carcinoma (OCCC) and often co-exists with activating mutations of PIK3CA. Although induction of pro-inflammatory cytokines has been observed in this cancer, the mechanism by which the two mutations synergistically activate cytokine genes remains elusive. Here, we established an in vitro model of OCCC by introducing ARID1A knockdown and mutant PIK3CA into a normal human ovarian epithelial cell line, resulting in cell transformation and cytokine gene induction. We demonstrate that loss of ARID1A impairs the recruitment of the Sin3A-HDAC complex, while the PIK3CA mutation releases RelA from IκB, leading to cytokine gene activation. We show that an NF-κB inhibitor partly attenuates the proliferation of OCCC and improves the efficacy of carboplatin both in cell culture and in a mouse model. Our study thus reveals the mechanistic link between ARID1A/PIK3CA mutations and cytokine gene induction in OCCC and suggests that NF-κB inhibition could be a potential therapeutic option. PMID:27681437

  18. The Galileo high gain antenna deployment anomaly

    NASA Technical Reports Server (NTRS)

    Johnson, Michael R.

    1994-01-01

    On April 11, 1991, the Galileo spacecraft executed a sequence that would open the spacecraft's High Gain Antenna. The Antenna's launch restraint had been released just after deployment sequence, the antenna, which opens like an umbrella, never reached the fully deployed position. The analyses and tests that followed allowed a conclusive determination of the likely failure mechanisms and pointed to some strategies to use for recovery of the high gain antenna.

  19. Can LENR Energy Gains Exceed 1000?

    NASA Astrophysics Data System (ADS)

    Nagel, David J.

    2011-03-01

    Energy gain is defined as the energy realized from reactions divided by the energy required to produce those reactions. Low Energy Nuclear Reactions (LENR) have already been measured to significantly exceed the energy gain of 10 projected from ITER,possibly 15 years from now. Electrochemical experiments using the Pd-D system have shown energy gains exceeding 10. Gas phase experiments with the Ni-H system were reported to yield energy gains of over 100. Neither of these reports has been adequately verified or reproduced. However, the question in the title still deserves consideration. If, as thought by many, it is possible to trigger nuclear reactions that yield MeV energies with chemical energies of the order of eV, then the most optimistic expectation is that LENR gains could approach one million. Hence, the very tentative answer to the question above is yes. However, if LENR could be initiated with some energy cost, and then continue to ``burn,'' very high energy gains might be realized. Consider a match and a pile of dry logs. The phenomenon termed ``heat after death'' will be examined to see if it might be the initial evidence for nuclear ``burning.''

  20. FEL gain optimisation and spontaneous radiation

    SciTech Connect

    Bali, L.M.; Srivastava, A.; Pandya, T.P.

    1995-12-31

    Colson have evaluated FEL gains for small deviations from perfect electron beam injection, with radiation of the same polarisation as that of the wiggler fields. We find that for optimum gain the polarisation of the optical field should be the same as that of the spontaneous emission under these conditions. With a helical wiggler the axial oscillations resulting from small departures from perfect electron beam injection lead to injection dependent unequal amplitudes and phases of the spontaneous radiation in the two transverse directions. Viewed along the axis therefore the spontaneous emission is elliptically polarised. The azimuth of the ellipse varies with the difference of phase of the two transverse components of spontaneous emission but the eccentricity remains the same. With planar wigglers the spontaneous emission viewed in the axial direction is linearly polarised, again with an injection dependent azimuth. For optimum coherent gain of a radiation field its polarisation characteristics must be the same as those of the spontaneous radiation with both types of wiggler. Thus, with a helical wiggler and the data reported earlier, an increase of 10% in the FEL gain at the fundamental frequency and of 11% at the fifth harmonic has been calculated in the small gain per pass limit. Larger enhancements in gain may result from more favourable values of input parameters.

  1. Context-specific adaptation of saccade gain

    NASA Technical Reports Server (NTRS)

    Shelhamer, Mark; Clendaniel, Richard A.

    2002-01-01

    Previous studies established that vestibular reflexes can have two adapted states (e.g., gain) simultaneously, and that a context cue (e.g., vertical eye position) can switch between the two states. The present study examined this phenomenon of context-specific adaptationfor horizontal saccades, using a variety of contexts. Our overall goal was to assess the efficacy of different context cues in switching between adapted states. A standard double-step paradigm was used to adapt saccade gain. In each experiment, we asked for a simultaneous gain decrease in one context and gain increase in another context, and then determined if a change in the context would invoke switching between the adapted states. Horizontal eye position worked well as a context cue: saccades with the eyes deviated to the right could be made to have higher gains while saccades with the eyes deviated to the left could be made to have lower gains. Vertical eye position was less effective. This suggests that the more closely related a context cue is to the response being adapted, the more effective it is. Roll tilt of the head, and upright versus supine orientations, were somewhat effective in context switching; these paradigms contain orientation of gravity with respect to the head as part of the context.

  2. Chemically Defined Medium and Caenorhabditis elegans: A Powerful Approach

    NASA Technical Reports Server (NTRS)

    Szewczyk, N. J.; Kozak, E.; Conley, C. A.

    2003-01-01

    C. elegans has been established as a powerful genetic system. Growth in a chemically defined medium (C. elegans Maintenance Medium (CeMM)) now allows standardization and systematic manipulation of the nutrients that animals receive. Liquid cultivation allows automated culturing and experimentation and should be of me in large-scale growth and screening of animals. Here we present our initial results from developing culture systems with CeMM. We find that CeMM is versatile and culturing is simple. CeMM can be used in a solid or liquid state, it can be stored unused for at least a year, unattended actively growing cultures may be maintained longer than with standard techniques, and standard C. elegans protocols work well with animals grown in defined medium. We also find that there are caveats of using defined medium. Animals in defined medium grow more slowly than on standard medium, appear to display adaptation to the defined medium, and display altered growth rates as they change defined medium composition. As was suggested with the introduction of C. elegans as a potential genetic system, use of defined medium with C. elegans should prove a powerful tool.

  3. Weight Gain following Pallidal Deep Brain Stimulation: A PET Study.

    PubMed

    Sauleau, Paul; Drapier, Sophie; Duprez, Joan; Houvenaghel, Jean-François; Dondaine, Thibaut; Haegelen, Claire; Drapier, Dominique; Jannin, Pierre; Robert, Gabriel; Le Jeune, Florence; Vérin, Marc

    2016-01-01

    The mechanisms behind weight gain following deep brain stimulation (DBS) surgery seem to be multifactorial and suspected depending on the target, either the subthalamic nucleus (STN) or the globus pallidus internus (GPi). Decreased energy expenditure following motor improvement and behavioral and/or metabolic changes are possible explanations. Focusing on GPi target, our objective was to analyze correlations between changes in brain metabolism (measured with PET) and weight gain following GPi-DBS in patients with Parkinson's disease (PD). Body mass index was calculated and brain activity prospectively measured using 2-deoxy-2[18F]fluoro-D-glucose PET four months before and four months after the start of GPi-DBS in 19 PD patients. Dopaminergic medication was included in the analysis to control for its possible influence on brain metabolism. Body mass index increased significantly by 0.66 ± 1.3 kg/m2 (p = 0.040). There were correlations between weight gain and changes in brain metabolism in premotor areas, including the left and right superior gyri (Brodmann area, BA 6), left superior gyrus (BA 8), the dorsolateral prefrontal cortex (right middle gyrus, BAs 9 and 46), and the left and right somatosensory association cortices (BA 7). However, we found no correlation between weight gain and metabolic changes in limbic and associative areas. Additionally, there was a trend toward a correlation between reduced dyskinesia and weight gain (r = 0.428, p = 0.067). These findings suggest that, unlike STN-DBS, motor improvement is the major contributing factor for weight gain following GPi-DBS PD, confirming the motor selectivity of this target. PMID:27070317

  4. Weight Gain following Pallidal Deep Brain Stimulation: A PET Study

    PubMed Central

    Sauleau, Paul; Drapier, Sophie; Duprez, Joan; Houvenaghel, Jean-François; Dondaine, Thibaut; Haegelen, Claire; Drapier, Dominique; Jannin, Pierre; Robert, Gabriel; Le Jeune, Florence; Vérin, Marc

    2016-01-01

    The mechanisms behind weight gain following deep brain stimulation (DBS) surgery seem to be multifactorial and suspected depending on the target, either the subthalamic nucleus (STN) or the globus pallidus internus (GPi). Decreased energy expenditure following motor improvement and behavioral and/or metabolic changes are possible explanations. Focusing on GPi target, our objective was to analyze correlations between changes in brain metabolism (measured with PET) and weight gain following GPi-DBS in patients with Parkinson’s disease (PD). Body mass index was calculated and brain activity prospectively measured using 2-deoxy-2[18F]fluoro-D-glucose PET four months before and four months after the start of GPi-DBS in 19 PD patients. Dopaminergic medication was included in the analysis to control for its possible influence on brain metabolism. Body mass index increased significantly by 0.66 ± 1.3 kg/m2 (p = 0.040). There were correlations between weight gain and changes in brain metabolism in premotor areas, including the left and right superior gyri (Brodmann area, BA 6), left superior gyrus (BA 8), the dorsolateral prefrontal cortex (right middle gyrus, BAs 9 and 46), and the left and right somatosensory association cortices (BA 7). However, we found no correlation between weight gain and metabolic changes in limbic and associative areas. Additionally, there was a trend toward a correlation between reduced dyskinesia and weight gain (r = 0.428, p = 0.067). These findings suggest that, unlike STN-DBS, motor improvement is the major contributing factor for weight gain following GPi-DBS PD, confirming the motor selectivity of this target. PMID:27070317

  5. Medium-depth chemical peels.

    PubMed

    Monheit, G D

    2001-07-01

    The combination medium-depth chemical peel (Jessner's solution +35% TCA) has been accepted as a safe, reliable, and effective method for the treatment of moderate photoaging skin. This article discusses the procedure in detail, including postoperative considerations. PMID:11599398

  6. An improved holographic recording medium

    NASA Technical Reports Server (NTRS)

    Gange, R. A.

    1973-01-01

    Solid, linear chain hydrocarbons with molecular weight ranging from about 300 to 2000 can serve as long-lived recording medium in optical memory system. Suitable recording hydrocarbons include microcrystalline waxes and low molecular weight polymers or ethylene.

  7. Condensation onto the skin as a means for water gain by tree frogs in tropical Australia.

    PubMed

    Tracy, Christopher R; Laurence, Nathalie; Christian, Keith A

    2011-10-01

    Green tree frogs, Litoria caerulea, in the wet-dry tropics of northern Australia remain active during the dry season with apparently no available water and temperatures that approach their lower critical temperature. We hypothesized that this surprising activity might be because frogs that are cooled during nighttime activity gain water from condensation by returning to a warm, humid tree hollow. We measured the mass gained when a cool frog moved into either a natural or an artificial hollow. In both hollows, water condensed on cool L. caerulea, resulting in water gains of up to 0.93% of body mass. We estimated that the water gained was more than the water that would be lost to evaporation during activity. The use of condensation as a means for water gain may be a significant source of water uptake for species like L. caerulea that occur in areas where free water is unavailable over extended periods.

  8. Analysis of thymic stromal cell subpopulations grown in vitro on extracellular matrix in defined medium. III. Growth conditions of human thymic epithelial cells and immunomodulatory activities in their culture supernatant.

    PubMed Central

    Schreiber, L; Eshel, I; Meilin, A; Sharabi, Y; Shoham, J

    1991-01-01

    We report here on a new approach to the cultivation of human thymic epithelial (HTE) cells, which apparently allows more faithful preservation of cell function. This approach, previously developed by us for mouse thymic epithelial (MTE) cells, is based on the use of culture plates coated with extracellular matrix (ECM), and on the use of serum-free, growth factor-supplemented medium. The nutritional requirements of HTE and MTE are somewhat different. Although both are critically dependent on ECM and insulin, they differ in their dependency on other growth factors: selenium and transferrin are much more important for HTE cells, whereas epidermal growth factor and hydrocortisone play a more essential role in MTE cultures. The epithelial nature of the cultured cells is indicated by positive staining with anti-keratin antibodies and by the presence of desmosomes and tonofilaments. The ultrastructural appearance of the cells further suggests high metabolic and secretory activities, not usually found in corresponding cell lines. The culture supernatant (CS) of HTE cells exhibited a strong enhancing effect on thymocyte response to Con A stimulation, as measured by cell proliferation and lymphokine production. The effect was observed on both human and mouse thymocytes, but was much stronger in the homologous combination. Thymic factors tested in parallel did not have such a differential effect. The dose-effect relationships were in the form of a bell-shaped curve, with fivefold enhancement of response at the peak and a measurable effect even with 1:1000 dilution, when human thymocytes were used. The responding thymocytes were those which do not bind peanut agglutinin and are resistant to hydrocortisone. The culture system described here may have advantages for the in vitro study of thymic stromal cell function. Images Figure 1 Figure 3 Figure 4 PMID:1783421

  9. [Medium energy meson research

    SciTech Connect

    Crowe, K.M.

    1992-01-01

    The activities of this group are primarily concerned with experiments using the Crystal Barrel Detector. This detector is installed and operating at the Low Energy Antiproton Ring (LEAR) at CERN. QCD, the modem theory of the strong interaction, is reasonably well understood at high energies, but unfortunately, low-energy QCD is still not well understood, and is far from being adequately tested. The Crystal Barrel experiments are designed to provide some of the tests. The basic line of research involves meson spectroscopy, analyses bearing on the quark and/or gluon content of nuclear states, and the exploration of mechanisms and rules which govern p[bar p] annihilation dynamics. The Crystal Barrel Detector detects and identifies charged and neutral particles with a geometric acceptance close to 100%. The principal component of the detector is an array of 1,380 CsI(TI) crystals. These crystals surround a Jet Drift Chamber (JDC), located in a 1.5 Tesla magnetic field, which measures the momentum and dE/dx of charged particles. One of the very interesting physics goals of the detector is a search for exotic mesonic states -- glueballs and hybrids. Annihilation at rest will be studied with both liquid and gaseous hydrogen targets. The gaseous target offers the possibility of triggering on atomic L-shell X rays so that specific initial angular momentum states can be studied.These topics as well as other related topics are discussed in this report.

  10. [Medium energy meson research

    SciTech Connect

    Crowe, K.M.

    1992-12-01

    The activities of this group are primarily concerned with experiments using the Crystal Barrel Detector. This detector is installed and operating at the Low Energy Antiproton Ring (LEAR) at CERN. QCD, the modem theory of the strong interaction, is reasonably well understood at high energies, but unfortunately, low-energy QCD is still not well understood, and is far from being adequately tested. The Crystal Barrel experiments are designed to provide some of the tests. The basic line of research involves meson spectroscopy, analyses bearing on the quark and/or gluon content of nuclear states, and the exploration of mechanisms and rules which govern p{bar p} annihilation dynamics. The Crystal Barrel Detector detects and identifies charged and neutral particles with a geometric acceptance close to 100%. The principal component of the detector is an array of 1,380 CsI(TI) crystals. These crystals surround a Jet Drift Chamber (JDC), located in a 1.5 Tesla magnetic field, which measures the momentum and dE/dx of charged particles. One of the very interesting physics goals of the detector is a search for exotic mesonic states -- glueballs and hybrids. Annihilation at rest will be studied with both liquid and gaseous hydrogen targets. The gaseous target offers the possibility of triggering on atomic L-shell X rays so that specific initial angular momentum states can be studied.These topics as well as other related topics are discussed in this report.

  11. Sound Pressure Level Gain in an Acoustic Metamaterial Cavity

    PubMed Central

    Song, Kyungjun; Kim, Kiwon; Hur, Shin; Kwak, Jun-Hyuk; Park, Jihyun; Yoon, Jong Rak; Kim, Jedo

    2014-01-01

    The inherent attenuation of a homogeneous viscous medium limits radiation propagation, thereby restricting the use of many high-frequency acoustic devices to only short-range applications. Here, we design and experimentally demonstrate an acoustic metamaterial localization cavity which is used for sound pressure level (SPL) gain using double coiled up space like structures thereby increasing the range of detection. This unique behavior occurs within a subwavelength cavity that is 1/10th of the wavelength of the incident acoustic wave, which provides up to a 13 dB SPL gain. We show that the amplification results from the Fabry-Perot resonance of the cavity, which has a simultaneously high effective refractive index and effective impedance. We also experimentally verify the SPL amplification in an underwater environment at higher frequencies using a sample with an identical unit cell size. The versatile scalability of the design shows promising applications in many areas, especially in acoustic imaging and underwater communication. PMID:25502279

  12. Decoupling control technology for medium STOL transports

    NASA Technical Reports Server (NTRS)

    Bird, D. K.; Neighbor, T. L.

    1976-01-01

    The advanced control technology is considered that is necessary to cope with the medium STOL transport landing problem and, in particular, the necessity to decouple with active control techniques. It is shown that the need to decouple is independent of the powered lift concept but that the provisioning for decoupling is most greatly dependent on the preassumed piloting technique. The implications of decoupling and active control techniques with respect to pilot technique options, handling quality criteria, flight control mechanization, and the use of piloted simulation as a design tool, are also discussed.

  13. Inactivation of the glutamine/amino acid transporter ASCT2 by 1,2,3-dithiazoles: proteoliposomes as a tool to gain insights in the molecular mechanism of action and of antitumor activity

    SciTech Connect

    Oppedisano, Francesca; Catto, Marco; Koutentis, Panayiotis A.; Nicolotti, Orazio; Pochini, Lorena; Koyioni, Maria; Introcaso, Antonellina; Michaelidou, Sophia S.; Carotti, Angelo; Indiveri, Cesare

    2012-11-15

    The ASCT2 transport system catalyses a sodium-dependent antiport of glutamine and other neutral amino acids which is involved in amino acid metabolism. A library of 1,2,3-dithiazoles was designed, synthesized and evaluated as inhibitors of the glutamine/amino acid ASCT2 transporter in the model system of proteoliposomes reconstituted with the rat liver transporter. Fifteen of the tested compounds at concentration of 20 μM or below, inhibited more than 50% the glutamine/glutamine antiport catalysed by the reconstituted transporter. These good inhibitors bear a phenyl ring with electron withdrawing substituents. The inhibition was reversed by 1,4-dithioerythritol indicating that the effect was likely owed to the formation of mixed sulfides with the protein's Cys residue(s). A dose–response analysis of the most active compounds gave IC{sub 50} values in the range of 3–30 μM. Kinetic inhibition studies indicated a non-competitive inhibition, presumably because of a potential covalent interaction of the dithiazoles with cysteine thiol groups that are not located at the substrate binding site. Indeed, computational studies using a homology structural model of ASCT2 transporter, suggested as possible binding targets, Cys-207 or Cys-210, that belong to the CXXC motif of the protein. -- Highlights: ► Non‐competitive inhibition of ASCT2 by 1,2,3-dithiazoles was studied in proteoliposomes. ► Different 1,2,3-dithiazoles were synthesized and evaluated as transporter inhibitors. ► Many compounds potently inhibited the glutamine/glutamine antiport catalyzed by ASCT2. ► The inhibition was reversed by DTE indicating reaction with protein Cys. ► The most active compounds gave IC{sub 50} in the range of 3–30 μM.

  14. Gain modulation by graphene plasmons in aperiodic lattice lasers

    NASA Astrophysics Data System (ADS)

    Chakraborty, S.; Marshall, O. P.; Folland, T. G.; Kim, Y.-J.; Grigorenko, A. N.; Novoselov, K. S.

    2016-01-01

    Two-dimensional graphene plasmon-based technologies will enable the development of fast, compact, and inexpensive active photonic elements because, unlike plasmons in other materials, graphene plasmons can be tuned via the doping level. Such tuning is harnessed within terahertz quantum cascade lasers to reversibly alter their emission. This is achieved in two key steps: first, by exciting graphene plasmons within an aperiodic lattice laser and, second, by engineering photon lifetimes, linking graphene’s Fermi energy with the round-trip gain. Modal gain and hence laser spectra are highly sensitive to the doping of an integrated, electrically controllable, graphene layer. Demonstration of the integrated graphene plasmon laser principle lays the foundation for a new generation of active, programmable plasmonic metamaterials with major implications across photonics, material sciences, and nanotechnology.

  15. Maternal obesity: pregnancy complications, gestational weight gain and nutrition.

    PubMed

    Guelinckx, I; Devlieger, R; Beckers, K; Vansant, G

    2008-03-01

    The obesity epidemic affects all, including women of reproductive age. One in five women attending prenatal care in the UK is obese. Prepregnancy obesity is associated with serious short- and long-term complications for mother and child. Furthermore, gestational weight gain (GWG) of obese pregnant women generally exceeds the Institute of Medicine recommended ranges. This observation can partially be explained by an unbalanced diet and lack of daily physical activity. Despite this, few lifestyle intervention trials in obese pregnant women are available. Two out of seven intervention trials focusing on GWG, nutrition and physical activity, reached a significant decrease in GWG. Developing guidelines to promote appropriated weight gain and healthy lifestyle in overweight and obese pregnant women remains a challenge. This review aims to summarize the complications associated with maternal prepregnancy overweight and obesity and to discuss possible strategies to improve the lifestyle habits of pregnant women.

  16. High Gain Submicrometer Optical Amplifier at Near-Infrared Communication Band.

    PubMed

    Wang, Xiaoxia; Zhuang, Xiujuan; Yang, Sen; Chen, Yu; Zhang, Qinglin; Zhu, Xiaoli; Zhou, Hong; Guo, Pengfei; Liang, Junwu; Huang, Yu; Pan, Anlian; Duan, Xiangfeng

    2015-07-10

    Nanoscale near-infrared optical amplification is important but remains a challenge to achieve. Here we report a unique design of silicon and erbium silicate core-shell nanowires for high gain submicrometer optical amplification in the near-infrared communication band. The high refraction index silicon core is used to tightly confine the optical field within the submicron structures, and the single crystalline erbium-ytterbium silicates shell is used as the highly efficient gain medium. Both theoretical and experimental results show that, by systematically tuning the core diameter and shell thickness, a large portion of the optical power can be selectively confined to the erbium silicate shell gain medium to enable a low loss waveguide and high gain optical amplifier. Experimental results further demonstrate that an optimized core-shell nanowire can exhibit an excellent net gain up to 31  dB mm(-1), which is more than 20 times larger than the previously reported best results on the micron-scale optical amplifiers.

  17. A Temperature-Based Gain Calibration Technique for Precision Radiometry

    NASA Astrophysics Data System (ADS)

    Parashare, Chaitali Ravindra

    Detecting extremely weak signals in radio astronomy demands high sensitivity and stability of the receivers. The gain of a typical radio astronomy receiver is extremely large, and therefore, even very small gain instabilities can dominate the received noise power and degrade the instrument sensitivity. Hence, receiver stabilization is of prime importance. Gain variations occur mainly due to ambient temperature fluctuations. We take a new approach to receiver stabilization, which makes use of active temperature monitoring and corrects for the gain fluctuations in post processing. This approach is purely passive and does not include noise injection or switching for calibration. This system is to be used for the Precision Array for Probing the Epoch of Reionization (PAPER), which is being developed to detect the extremely faint neutral hydrogen (HI) signature of the Epoch of Reionization (EoR). The epoch of reionization refers to the period in the history of the Universe when the first stars and galaxies started to form. When there are N antenna elements in the case of a large scale array, all elements may not be subjected to the same environmental conditions at a given time. Hence, we expect to mitigate the gain variations by monitoring the physical temperature of each element of the array. This stabilization approach will also benefit experiments like EDGES (Experiment to Detect the Global EoR Signature) and DARE (Dark Ages Radio Explorer), which involve a direct measurement of the global 21 cm signal using a single antenna element and hence, require an extremely stable system. This dissertation focuses on the development and evaluation of a calibration technique that compensates for the gain variations caused due to temperature fluctuations of the RF components. It carefully examines the temperature dependence of the components in the receiver chain. The results from the first-order field instrument, called a Gainometer (GoM), highlight the issue with the cable

  18. Compression gain of spin wave signals in a magnonic YIG waveguide with thermal non-uniformity

    NASA Astrophysics Data System (ADS)

    Kolokoltsev, O.; Gómez-Arista, Ivan; Qureshi, N.; Acevedo, A.; Ordóñez-Romero, César L.; Grishin, A.

    2015-03-01

    We report on the observation of the compression gain of the signals carried by surface spin waves (MSSWs) in yittrium iron garnet films as a result of non-uniform optical heating of the spin wave medium. Efficient gain takes place if a frequency downshift of the spin wave spectrum induced by the heating is compensated by the corresponding non-uniformity of the bias magnetic field. It is proposed that the effect can be understood in part as an interaction between spin waves and a thermally induced potential well in the sample.

  19. Redesign of a Variable-Gain Output Feedback Longitudinal Controller Flown on the High-Alpha Research Vehicle (HARV)

    NASA Technical Reports Server (NTRS)

    Ostroff, Aaron J.

    1998-01-01

    This paper describes a redesigned longitudinal controller that flew on the High-Alpha Research Vehicle (HARV) during calendar years (CY) 1995 and 1996. Linear models are developed for both the modified controller and a baseline controller that was flown in CY 1994. The modified controller was developed with three gain sets for flight evaluation, and several linear analysis results are shown comparing the gain sets. A Neal-Smith flying qualities analysis shows that performance for the low- and medium-gain sets is near the level 1 boundary, depending upon the bandwidth assumed, whereas the high-gain set indicates a sensitivity problem. A newly developed high-alpha Bode envelope criterion indicates that the control system gains may be slightly high, even for the low-gain set. A large motion-base simulator in the United Kingdom was used to evaluate the various controllers. Desired performance, which appeared to be satisfactory for flight, was generally met with both the low- and medium-gain sets. Both the high-gain set and the baseline controller were very sensitive, and it was easy to generate pilot-induced oscillation (PIO) in some of the target-tracking maneuvers. Flight target-tracking results varied from level 1 to level 3 and from no sensitivity to PIO. These results were related to pilot technique and whether actuator rate saturation was encountered.

  20. Intron loss and gain in Drosophila.

    PubMed

    Coulombe-Huntington, Jasmin; Majewski, Jacek

    2007-12-01

    Although introns were first discovered almost 30 years ago, their evolutionary origin remains elusive. In this work, we used multispecies whole-genome alignments to map Drosophila melanogaster introns onto 10 other fully sequenced Drosophila genomes. We were able to find 1,944 sites where an intron was missing in one or more species. We show that for most (>80%) of these cases, there is no leftover intronic sequence or any missing exonic sequence, indicating exact intron loss or gain events. We used parsimony to classify these differences as 1,754 intron loss events and 213 gain events. We show that lost and gained introns are significantly shorter than average and flanked by longer than average exons. They also display quite distinct phase distributions and show greater than average similarity between the 5' splice site and its 3' partner splice site. Introns that have been lost in one or more species evolve faster than other introns, occur in slowly evolving genes, and are found adjacent to each other more often than would be expected for independent single losses. Our results support the cDNA recombination mechanism of intron loss, suggest that selective pressures affect site-specific loss rates, and show conclusively that intron gain has occurred within the Drosophila lineage, solidifying the "introns-middle" hypothesis and providing some hints about the gain mechanism.