Science.gov

Sample records for active transmission elements

  1. Data transmission element for downhole drilling components

    DOEpatents

    Hall, David R.; Hall, Jr., H. Tracy; Pixton, David S.; Dahlgren, Scott; Fox, Joe; Sneddon, Cameron; Briscoe, Michael

    2006-01-31

    A robust data transmission element for transmitting information between downhole components, such as sections of drill pipe, in the presence of hostile environmental conditions, such as heat, dirt, rocks, mud, fluids, lubricants, and the like. The data transmission element components include a generally U-shaped annular housing, a generally U-shaped magnetically conductive, electrically insulating element such as ferrite, and an insulated conductor. Features on the magnetically conducting, electrically insulating element and the annular housing create a pocket when assembled. The data transmission element is filled with a polymer to retain the components within the annular housing by filling the pocket with the polymer. The polymer can bond with the annular housing and the insulated conductor but preferably not the magnetically conductive, electrically insulating element. A data transmission element is mounted within a recess proximate a mating surface of a downhole drilling component, such as a section of drill pipe.

  2. Development of thermoplastic coated multifunctional transmission elements

    NASA Astrophysics Data System (ADS)

    Golaz, B.; Michaud, V.; de Oliveira, R.; Månson, J.-A. E.

    2012-04-01

    We report on key challenges of the development of steel cords reinforced thermoplastic elastomer composites with smart functionalities: adhesion tailoring for a durable mechanical load transfer through steel cords or other transmission elements by the use of surface treatments and primers, and integrated distributed temperature and strain sensing by the use of embedded fiber optic sensors. Traditional surface treatments including silane coupling agent were outperformed in processing time, adhesion and durability by a fast-curing coupling method using a UV-curable primer; and the integrated distributed temperature and strain sensing capability was demonstrated. The practical applications of the resulting multifunctional transmission element are then discussed in light of these results.

  3. Transmissive Diffractive Optical Element Solar Concentrators

    NASA Technical Reports Server (NTRS)

    Baron, Richard; Moynihan, Philip; Price, Douglas

    2008-01-01

    Solar-thermal-radiation concentrators in the form of transmissive diffractive optical elements (DOEs) have been proposed as alternatives to mirror-type solar concentrators now in use. In comparison with functionally equivalent mirror-type solar concentrators, the transmissive, diffractive solar concentrators would weigh and cost less, and would be subject to relaxed mechanical tolerances. A DOE concentrator would be made from a thin, flat disk or membrane of a transmissive material having a suitable index of refraction. By virtue of its thinness, the DOE concentrator would have an areal mass density significantly less than that of a functionally equivalent conventional mirror. The DOE concentrator would have a relatively wide aperture--characterized by a focal-length/aperture-diameter ratio ('f number') on the order of 1. A kinoform (a surface-relief phase hologram) of high diffractive order would be microfabricated onto one face of the disk. The kinoform (see figure) would be designed to both diffract and refract incident solar radiation onto a desired focal region, without concern for forming an image of the Sun. The high diffractive order of this kinoform (in contradistinction to the low diffractive orders of some other kinoforms) would be necessary to obtain the desired f number of 1, which, in turn, would be necessary for obtaining a desired concentration ratio of 2,500 or greater. The design process of optimizing the concentration ratio of a proposed DOE solar concentrator includes computing convolutions of the optical bandwidth of the Sun with the optical transmission of the diffractive medium. Because, as in the cases of other non-imaging, light-concentrating optics, image quality is not a design requirement, the process also includes trading image quality against concentration ratio. A baseline design for one example calls for an aperture diameter of 1 m. This baseline design would be scalable to a diameter as large as 10 m, or to a smaller diameter for a

  4. Non-conforming finite element methods for transmission eigenvalue problem

    NASA Astrophysics Data System (ADS)

    Yang, Yidu; Han, Jiayu; Bi, Hai

    2016-08-01

    The transmission eigenvalue problem is an important and challenging topic arising in the inverse scattering theory. In this paper, for the Helmholtz transmission eigenvalue problem, we give a weak formulation which is a nonselfadjoint linear eigenvalue problem. Based on the weak formulation, we first discuss the non-conforming finite element approximation, and prove the error estimates of the discrete eigenvalues obtained by the Adini element, Morley-Zienkiewicz element, modified-Zienkiewicz element et. al. And we report some numerical examples to validate the efficiency of our approach for solving transmission eigenvalue problem.

  5. Ordering the bestiary of genetic elements transmissible by conjugation

    PubMed Central

    Garcillán-Barcia, Maria Pilar; de la Cruz, Fernando

    2013-01-01

    Phylogenetic reconstruction of three highly conserved proteins involved in bacterial conjugation (relaxase, coupling protein and a type IV secretion system ATPase) allowed the classification of transmissible elements in relaxase MOB families and mating pair formation MPF groups. These evolutionary studies point to the existence of a limited number of module combinations in transmissible elements, preferentially associated with specific genetic or environmental backgrounds. A practical protocol based on the MOB classification was implemented to detect and assort transmissible plasmids and integrative elements from γ-Proteobacteria. It was called “Degenerate Primer MOB Typing” or DPMT. It resulted in a powerful technique that discovers not only backbones related to previously classified elements (typically by PCR-based replicon typing or PBRT), but also distant new members sharing a common evolutionary ancestor. The DPMT method, conjointly with PBRT, promises to be useful to gain information on plasmid backbones and helpful to investigate the dissemination routes of transmissible elements in microbial ecosystems. PMID:23734300

  6. Intertwined arbovirus transmission activity: reassessing the transmission cycle paradigm

    PubMed Central

    Diaz, Luis A.; Flores, Fernando S.; Quaglia, Agustín; Contigiani, Marta S.

    2013-01-01

    Arboviruses are emerging/reemerging infectious agents worldwide. The factors within this scenario include vector and host population fluctuations, climatic changes, anthropogenic activities that disturb ecosystems, an increase in international flights, human mobility, and genetic mutations that allow spill-over phenomenon. Arboviruses are maintained by biologic transmission among vectors and hosts. Sometimes this biological transmission is specific and includes one vector and host species such as Chikungunya (CHIKV), Dengue (DENV), and urban Yellow Fever (YFV). However, most of the arboviruses are generalist and they use many vectors and hosts species. From this perspective, arboviruses are maintained through a transmission network rather than a transmission cycle. This allows us to understand the complexity and dynamics of the transmission and maintenance of arboviruses in the ecosystems. The old perspective that arboviruses are maintained in close and stable transmission cycles should be modified by a new more integrative and dynamic idea, representing the real scenario where biological interactions have a much broader representation, indicating the constant adaptability of the biological entities. PMID:23335900

  7. Active control of helicopter transmission noise

    NASA Astrophysics Data System (ADS)

    Spencer, R. H.; Burke, M. J.; Tye, G. W.

    An account is given of an effort to reduce helicopter transmission noise by 10 dB, using active methods, as part of the NASA-Lewis/U.S. Army Propulsion Directorate Advanced Rotorcraft Transmission technology integration and demonstration program. The transmission used as a test stand is that of the CH-47C forward rotor. Attention is presently given to the active control system's actuators, sensors, and control algorithms.

  8. Active control of helicopter transmission noise

    NASA Technical Reports Server (NTRS)

    Spencer, R. H.; Burke, M. J.; Tye, G. W.

    1991-01-01

    An account is given of an effort to reduce helicopter transmission noise by 10 dB, using active methods, as part of the NASA-Lewis/U.S. Army Propulsion Directorate Advanced Rotorcraft Transmission technology integration and demonstration program. The transmission used as a test stand is that of the CH-47C forward rotor. Attention is presently given to the active control system's actuators, sensors, and control algorithms.

  9. Hydraulic servo for friction coupling element of automatic transmission

    SciTech Connect

    Sumiya, K.; Kano, T.; Kubo, S.; Watanabe, K.

    1987-07-28

    A hydraulic servo is described for a friction coupling element in an automatic transmission including a casing, the hydraulic servo, comprising: an annular drum having a first cylinder, a second cylinder, and a side wall connecting the first and second cylinders all integrally formed together as a single piece by press forming, the first cylinder having splines on its outer cylindrical surface and fixed to the interior of the casing through the splines and the second cylinder having splines on its inner cylindrical surface; a press-formed third cylinder joined to the side wall of the annular drum by a fully encircling weld; a piston fitted between the first cylinder and the third cylinder; and biasing means provided between the third cylinder and the second cylinder for returning the piston.

  10. Hydraulic servo for friction coupling element of automatic transmission

    SciTech Connect

    Sumiya, K.; Watanabe, K.; Kubo, S.

    1987-09-01

    A hydraulic servo is described for a friction coupling element in an automatic transmission including a casing, comprising: an annular drum fixed to the automatic transmission casing and having an outer cylinder, as in inner cylinder, a sidewall connecting the outer and inner cylinders, and an intermediate cylinder connected to the sidewall between the outer and inner cylinders to divide the interior of the drum into outer and inner annular spaces; a piston slidably mounted within the outer annular space, between the outer and intermediate cylinders, the piston having a terminal axially extending guide sleeve portion; and return biasing means including: a connecting member having one end fixed to the piston and abutting the guide sleeve portion and the other end located in the inner annular space, between the inner cylinder and the intermediate cylinder; a retainer fixed to the inner cylinder, at a position axially inward of the guide sleeve with respect to the sidewall when the piston is fully retracted, and; return springs interposed within the inner annular space between the other end of the connecting member and the retainer.

  11. Active control of vibration transmission through struts

    NASA Astrophysics Data System (ADS)

    Pelinescu, Ion; Balachandran, Balakumar

    1998-07-01

    In this work, analytical investigations into active control of longitudinal and flexural vibrations transmitted through a cylindrical strut are conducted. A mechanics based model for a strut fitted with a piezoelectric actuator is developed. For harmonic disturbances, a linear dynamic formulation describing the motion of the actuator is integrated with the formulation describing wave transmission through the strut, and the resulting system is studied in the frequency domain. Open-loop studies are conducted with the aid of numerical simulations, and the potential of active control schemes to attenuate the transmitted vibrations over the frequency range of 10 Hz to 6000 Hz is examined. The relevance of the current work to control of helicopter cabin interior noise is also discussed.

  12. SORPTION OF ELEMENTAL MERCURY BY ACTIVATED CARBONS

    EPA Science Inventory

    The mechanisms and rate of elemental mercury (HgO) capture by activated carbons have been studied using a bench-scale apparatus. Three types of activated carbons, two of which are thermally activated (PC-100 and FGD) and one with elemental sulfur (S) impregnated in it (HGR), were...

  13. Application of High Order Acoustic Finite Elements to Transmission Losses and Enclosure Problems

    NASA Technical Reports Server (NTRS)

    Craggs, A.; Stevenson, G.

    1985-01-01

    A family of acoustic finite elements was developed based on C continuity (acoustic pressure being the nodal variable) and the no-flow condition. The family include triangular, quadrilateral and hexahedral isoparametric elements with linear quadratic and cubic variation in modelling and distortion. Of greatest use in problems with irregular boundaries are the cubic isoparametric elements: the 32 node hexahedral element for three-dimensional systems; and the twelve node quadrilateral and ten node triangular elements for two-dimensional/axisymmetric applications. These elements were applied to problems involving cavity resonances, transmission loss in silencers and the study of end effects, using a Floating Point Systems 164 attached array processor accessed through an Amdahl 5860 mainframe. The elements are presently being used to study the end effects associated with duct terminations within finite enclosures. The transmission losses with various silencers and sidebranches in ducts is also being studied using the same elements.

  14. Information transmission in oscillatory neural activity.

    PubMed

    Koepsell, Kilian; Sommer, Friedrich T

    2008-11-01

    Periodic neural activity not locked to the stimulus or to motor responses is usually ignored. Here, we present new tools for modeling and quantifying the information transmission based on periodic neural activity that occurs with quasi-random phase relative to the stimulus. We propose a model to reproduce characteristic features of oscillatory spike trains, such as histograms of inter-spike intervals and phase locking of spikes to an oscillatory influence. The proposed model is based on an inhomogeneous Gamma process governed by a density function that is a product of the usual stimulus-dependent rate and a quasi-periodic function. Further, we present an analysis method generalizing the direct method (Rieke et al. in Spikes: exploring the neural code. MIT Press, Cambridge, 1999; Brenner et al. in Neural Comput 12(7):1531-1552, 2000) to assess the information content in such data. We demonstrate these tools on recordings from relay cells in the lateral geniculate nucleus of the cat. PMID:18985377

  15. Fabrication of a phase transmission holographic optical element in polycarbonate and its characterization.

    PubMed

    Vadivelan, V; Chandar Shekar, B

    2016-08-10

    The phase transmission holographic optical element in silver halide holographic emulsion, especially for holographic collimator sights, is fabricated and the desired diffraction efficiency is obtained with very high transmission. One of the main drawbacks of these holograms are that they become dark by being exposed under sunlight, and this darkness drastically reduces the visible transmission and diffraction efficiency of a holographic optical element, hence it is not suitable for weapon sight application. To overcome this problem, we transferred a holographic optical element with a reticle image from silver halide into polycarbonate by using copying, electroforming, and recombination techniques. The holographic optical element in polycarbonate has many advantages; the detailed method of fabrication, transfer, and its characterization are presented. The very interesting result of diffraction efficiency variation with angle obtained in polycarbonate is discussed. PMID:27534494

  16. Transmission research activities at NASA Lewis Research Center

    NASA Technical Reports Server (NTRS)

    Lewicki, D. G.

    1990-01-01

    A joint research program, to advance the technology of rotorcraft transmissions, consists of analytical and experimental efforts to achieve the overall goals of reducing transmission weight and noise, while increasing life and reliability. Recent activities in the areas of transmission and related component research are highlighted. Current areas include specific technologies in support of military rotary wing aviation, gearing technology, transmission noise reduction studies, a recent interest in gearbox diagnostics, and advanced transmission system studies. Results of recent activities are presented along with near term research plans.

  17. Boundary element method for calculation of elastic wave transmission in two-dimensional phononic crystals

    NASA Astrophysics Data System (ADS)

    Li, FengLian; Wang, YueSheng; Zhang, ChuanZeng

    2016-06-01

    A boundary element method (BEM) is presented to compute the transmission spectra of two-dimensional (2-D) phononic crystals of a square lattice which are finite along the x-direction and infinite along the y-direction. The cross sections of the scatterers may be circular or square. For a periodic cell, the boundary integral equations of the matrix and the scatterers are formulated. Substituting the periodic boundary conditions and the interface continuity conditions, a linear equation set is formed, from which the elastic wave transmission can be obtained. From the transmission spectra, the band gaps can be identified, which are compared with the band structures of the corresponding infinite systems. It is shown that generally the transmission spectra completely correspond to the band structures. In addition, the accuracy and the efficiency of the boundary element method are analyzed and discussed.

  18. On sound transmission into a stiffened cylindrical shell with rings and stringers treated as discrete elements

    NASA Technical Reports Server (NTRS)

    Koval, L. R.

    1980-01-01

    In the context of the transmission of airborne noise into an aircraft fuselage, a mathematical model is presented for the transmission of an oblique plane sound wave into a finite cylindrical shell stiffened by stringers and ring frames. The rings and stringers are modeled as discrete structural elements. The numerical case studied was typical of a narrow-bodied jet transport fuselage. The numerical results show that the ring-frequency dip in the transmission loss curve that is present for a monocoque shell is still present in the case of a stiffened shell. The ring frequency effect is a result of the cylindrical geometry of the shell. Below the ring frequency, stiffening does not appear to have any significant effect on transmission loss, but above the ring frequency, stiffeners can enhance the transmission loss of a cylindrical shell.

  19. Optimizing diffraction efficiency for transmission holographic optical elements with HARMAN holographic materials

    NASA Astrophysics Data System (ADS)

    Smith, Steven L.; Harvey, Karen; Richardson, Martin; Blyth, Jeff

    2011-02-01

    HARMAN technology's new holographic emulsions; red sensitive and green sensitive assisted by smaller grain sizes, novel sensitization and coating technology have been shown to achieve high diffraction efficiencies and narrow band reconstruction capabilities. Authors demonstrate processing optimizations and material behavior characteristics for Transmission image Masters as well as Holographic Optical Elements (HOE's).

  20. Finite Element Analysis of the Maximum Stress at the Joints of the Transmission Tower

    NASA Astrophysics Data System (ADS)

    Itam, Zarina; Beddu, Salmia; Liyana Mohd Kamal, Nur; Bamashmos, Khaled H.

    2016-03-01

    Transmission towers are tall structures, usually a steel lattice tower, used to support an overhead power line. Usually, transmission towers are analyzed as frame-truss systems and the members are assumed to be pin-connected without explicitly considering the effects of joints on the tower behavior. In this research, an engineering example of joint will be analyzed with the consideration of the joint detailing to investigate how it will affect the tower analysis. A static analysis using STAAD Pro was conducted to indicate the joint with the maximum stress. This joint will then be explicitly analyzed in ANSYS using the Finite Element Method. Three approaches were used in the software which are the simple plate model, bonded contact with no bolts, and beam element bolts. Results from the joint analysis show that stress values increased with joint details consideration. This proves that joints and connections play an important role in the distribution of stress within the transmission tower.

  1. Finite element analysis using NASTRAN applied to helicopter transmission vibration/noise reduction

    NASA Technical Reports Server (NTRS)

    Howells, R. W.; Sciarra, J. J.

    1975-01-01

    A finite element NASTRAN model of the complete forward rotor transmission housing for the Boeing Vertol CH-47 helicopter was developed and applied to reduce transmission vibration/noise at its source. In addition to a description of the model, a technique for vibration/noise prediction and reduction is outlined. Also included are the dynamic response as predicted by NASTRAN, test data, the use of strain energy methods to optimize the housing for minimum vibration/noise, and determination of design modifications which will be manufactured and tested. The techniques presented are not restricted to helicopters but are applicable to any power transmission system. The transmission housing model developed can be used further to evaluate static and dynamic stresses, thermal distortions, deflections and load paths, fail-safety/vulnerability, and composite materials.

  2. The Heritable Activation of Cryptic Suppressor-Mutator Elements by an Active Element

    PubMed Central

    Fedoroff, N.

    1989-01-01

    A weakly active maize Suppressor-mutator (Spm-w) element is able to heritably activate cryptic Spm elements in the maize genome. The spontaneous activation frequency, which is 1-5 X 10(-5) in the present genetic background, increases by about 100-fold in the presence of an Spm-w and remains an order of magnitude above the background level a generation after removal of the activating Spm-w. Sectorial somatic reactivation of cryptic elements can be detected phenotypically in kernels. Selection of such kernels constitutes an efficient selection for plants with reactivated Spm elements. Analysis of the reactivation process reveals that it is gradual and proceeds through genetically metastable intermediates that exhibit different patterns of element expression during plant development. Newly reactivated elements tend to return to an inactive form. However, the probability that an element will remain in a heritably active state increases when the element is maintained in the presence of an active Spm element for several generations. PMID:2541047

  3. Finite Element Development of Honeycomb Panel Configurations with Improved Transmission Loss

    NASA Technical Reports Server (NTRS)

    Grosveld, Ferdinand W.; Palumbo, Daniel L.; Klos, Jacob; Castle, William D.

    2006-01-01

    The higher stiffness-to-mass ratio of a honeycomb panel compared to a homogeneous panel results in a lower acoustic critical frequency. Above the critical frequency the panel flexural wave speed is acoustically fast and the structure becomes a more efficient radiator with associated lower sound transmission loss. Finite element models of honeycomb sandwich structures are presented featuring areas where the core is removed from the radiating face sheet disrupting the supersonic flexural and shear wave speeds that exist in the baseline honeycomb panel. These modified honeycomb panel structures exhibit improved transmission loss for a pre-defined diffuse field sound excitation. The models were validated by the sound transmission loss of honeycomb panels measured in the Structural Acoustic Loads and Transmission (SALT) facility at the NASA Langley Research Center. A honeycomb core panel configuration is presented exhibiting a transmission loss improvement of 3-11 dB compared to a honeycomb baseline panel over a frequency range from 170 Hz to 1000 Hz. The improved transmission loss panel configuration had a 5.1% increase in mass over the baseline honeycomb panel, and approximately twice the deflection when excited by a static force.

  4. The application of finite element techniques to acoustic transmission in lined ducts with flow

    NASA Technical Reports Server (NTRS)

    Astley, R. J.; Eversman, W.

    1979-01-01

    The finite element method (FEM) is used to analyze the propagation of sound in two-dimensional nonuniform ducts carrying a compressible subsonic mean flow. Galerkin and residual least squares (RLS) methods with natural and forced boundary conditions are considered. The accuracy of FEM results for the eigenvalue and transmission problems is assessed by comparison with alternative numerical schemes for nonuniform ducts. The results presented and those from associated investigations indicate that modal coupling is a significant feature of the acoustic field, especially at high Mach numbers. A multimodal model therefore appears to be essential if any reliable conclusions are to be drawn in the context of turbofan inlet regions. Improvements to the eigenvalue scheme following the implementation of higher-order Hermitian elements indicate a similar modification for the transmission problem.

  5. 3D elemental sensitive imaging using transmission X-ray microscopy.

    PubMed

    Liu, Yijin; Meirer, Florian; Wang, Junyue; Requena, Guillermo; Williams, Phillip; Nelson, Johanna; Mehta, Apurva; Andrews, Joy C; Pianetta, Piero

    2012-09-01

    Determination of the heterogeneous distribution of metals in alloy/battery/catalyst and biological materials is critical to fully characterize and/or evaluate the functionality of the materials. Using synchrotron-based transmission x-ray microscopy (TXM), it is now feasible to perform nanoscale-resolution imaging over a wide X-ray energy range covering the absorption edges of many elements; combining elemental sensitive imaging with determination of sample morphology. We present an efficient and reliable methodology to perform 3D elemental sensitive imaging with excellent sample penetration (tens of microns) using hard X-ray TXM. A sample of an Al-Si piston alloy is used to demonstrate the capability of the proposed method. PMID:22349401

  6. Identification of light elements in silicon nitride by aberration-corrected scanning transmission electron microscopy.

    PubMed

    Idrobo, Juan C; Walkosz, Weronika; Klie, Robert F; Oğüt, Serdar

    2012-12-01

    In silicon nitride structural ceramics, the overall mechanical and thermal properties are controlled by the atomic and electronic structures at the interface between the ceramic grains and the amorphous intergranular films (IGFs) formed by various sintering additives. In the last ten years the atomic arrangements of heavy elements (rare-earths) at the Si(3)N(4)/IGF interfaces have been resolved. However, the atomic position of light elements, without which it is not possible to obtain a complete description of the interfaces, has been lacking. This review article details the authors' efforts to identify the atomic arrangement of light elements such as nitrogen and oxygen at the Si(3)N(4)/SiO(2) interface and in bulk Si(3)N(4) using aberration-corrected scanning transmission electron microscopy. PMID:22726263

  7. Lumped-element model of a tapered transmission line for impedance matching in a pulsed power system

    NASA Astrophysics Data System (ADS)

    Lee, Kun-A.; Ko, Kwang-Cheol

    2016-07-01

    In a pulsed power system, impedance matching is one of the significant factors for increasing the efficiency of the system. One of the most general methods for impedance matching is to use a tapered transmission line. Because the characteristics of a tapered transmission line are changed continuously according to its position, modeling the tapered transmission line by using lumped elements is difficult. In this study, we investigated a tapered transmission line to match the impedance of power supply to that of a load by using lumped elements especially in a pulsed power system. In modeling the tapered transmission line, we used the concept of a transmission, and we introduced an efficient modeling method. We propose a simulation model based on the investigation results. The results of the study will be useful for research on tapered transmission lines.

  8. Analysis of transmission lines loaded with pairs of coupled resonant elements and application to sensors

    NASA Astrophysics Data System (ADS)

    Naqui, J.; Su, L.; Mata, J.; Martín, F.

    2015-06-01

    This paper is focused on the analysis of transmission lines loaded with pairs of magnetically coupled resonators. We have considered two different structures: (i) a microstrip line loaded with pairs of stepped impedance resonators (SIRs), and (ii) a coplanar waveguide (CPW) transmission line loaded with pairs of split ring resonators (SRRs). In both cases, the line exhibits a single resonance frequency (transmission zero) if the resonators are identical (symmetric structure with regard to the line axis), and this resonance is different to the one of the line loaded with a single resonator due to inter-resonator coupling. If the structures are asymmetric, inter-resonator coupling enhances the distance between the two split resonance frequencies that arise. In spite that the considered lines and loading resonators are very different and are described by different lumped element equivalent circuit models, the phenomenology associated to the effects of coupling is exactly the same, and the resonance frequencies are given by identical expressions. The reported lumped element circuit models of both structures are validated by comparing the circuit simulations with extracted parameters with both electromagnetic simulations and experimental data. These structures can be useful for the implementation of microwave sensors based on symmetry properties.

  9. Use of element model to evaluate transmissibility reduction due to barriers

    SciTech Connect

    Svanes, T.; South, D.; Dronen, O.M.

    1997-08-01

    Water breakthrough has been observed a year earlier than expected in the productive Oseberg Formation in the Veslefrikk Field. Production data revealed extensive water override, whereas the opposite situation was expected based on a homogeneous and coarse flow simulation model. A new model was developed to include geological heterogeneities using a simple upscaling method. The Oseberg Fm. consists of an upper homogeneous unit (zone 2) and a lower unit containing thin barriers of shale and calcite cemented sandstone (zone 1). The barrier content varies laterally. When barriers are distributed in a complex 3D pattern, they reduce the upscaled horizontal transmissibility more than what is obtained by multiplying the sand permeability by the net-to-gross ratio (N/G). However, the transmissibility reduction strongly depends on the spatial distribution of barriers and their geometry. Therefore, a fine scale element model was used to derive the average transmissibility reduction as a function of N/G for alternative geological descriptions of the barriers. A geo-statistical method called General Marked Point Process was used to generate the fine scale descriptions. This work has resulted in a simple upscaling routine for horizontal transmissibility, which represents an effective bridge between geological evaluation of uncertainties and fluid flow simulation. The method combines geo-statistical and deterministic modelling in an elegant manner, recognising that most often these methods complement one another.

  10. Calculation of transmission line impedances using the ANSYS finite element program

    SciTech Connect

    Johnson, M.E.

    1984-06-29

    This paper describes numerical techniques for calculating the capacitance of an arbitrary two conductor structure. For two dimensional structures the capacitance per unit length can be easily related to the characteristic impedance of a transmission line with the same cross section. Note that this is true for lines operated below their cut off frequency, i.e., TEM mode only. Thus, one can compute the impedance of an arbitrarily shaped line. The method using the ANSYS finite element program is being used to design the high voltage transmission line for the Yale streamer chamber. This line has a transition piece between two different cross sections. It is being modeled by taking several slices throughout the transition region.

  11. Robust atomic resolution imaging of light elements using scanning transmission electron microscopy

    SciTech Connect

    Findlay, S. D.; Shibata, N.; Sawada, H.; Okunishi, E.; Kondo, Y.; Yamamoto, T.; Ikuhara, Y.

    2009-11-09

    We show that an annular detector placed within the bright field cone in scanning transmission electron microscopy allows direct imaging of light elements in crystals. In contrast to common high angle annular dark field imaging, both light and heavy atom columns are visible simultaneously. In contrast to common bright field imaging, the images are directly and robustly interpretable over a large range of thicknesses. We demonstrate this through systematic simulations and present a simple physical model to obtain some insight into the scattering dynamics.

  12. Television transmission at end of second extravehicular activity

    NASA Technical Reports Server (NTRS)

    1971-01-01

    Astronaut Edgar D. Mitchell, Apollo 14 lunar module pilot, can be seen throwing a 'javelin' left handed during a television transmission near the close of the second extravehicular activity (EVA-2) at the Apollo 14 Fra Mauro landing site. Mitchell used the staff of the Solar Wind Composition experiment as the 'javelin'. Behind Mitchell is Astronaut Alan B. Shepard Jr., commander. Also visible in the picture are the erectable S-Band antenna (left foreground) and Lunar Module (left background) (20783); Shepard can be seen preparing to swing at a golf ball during television transmission at end of EVA-2 (20784).

  13. A study of sound transmission in an abstract middle ear using physical and finite element models.

    PubMed

    Gonzalez-Herrera, Antonio; Olson, Elizabeth S

    2015-11-01

    The classical picture of middle ear (ME) transmission has the tympanic membrane (TM) as a piston and the ME cavity as a vacuum. In reality, the TM moves in a complex multiphasic pattern and substantial pressure is radiated into the ME cavity by the motion of the TM. This study explores ME transmission with a simple model, using a tube terminated with a plastic membrane. Membrane motion was measured with a laser interferometer and pressure on both sides of the membrane with micro-sensors that could be positioned close to the membrane without disturbance. A finite element model of the system explored the experimental results. Both experimental and theoretical results show resonances that are in some cases primarily acoustical or mechanical and sometimes produced by coupled acousto-mechanics. The largest membrane motions were a result of the membrane's mechanical resonances. At these resonant frequencies, sound transmission through the system was larger with the membrane in place than it was when the membrane was absent. PMID:26627771

  14. Human prion protein sequence elements impede cross-species chronic wasting disease transmission

    PubMed Central

    Kurt, Timothy D.; Jiang, Lin; Fernández-Borges, Natalia; Bett, Cyrus; Liu, Jun; Yang, Tom; Spraker, Terry R.; Castilla, Joaquín; Eisenberg, David; Kong, Qingzhong; Sigurdson, Christina J.

    2015-01-01

    Chronic wasting disease (CWD) is a fatal prion disease of North American deer and elk and poses an unclear risk for transmission to humans. Human exposure to CWD occurs through hunting activities and consumption of venison from prion-infected animals. Although the amino acid residues of the prion protein (PrP) that prevent or permit human CWD infection are unknown, NMR-based structural studies suggest that the β2-α2 loop (residues 165–175) may impact species barriers. Here we sought to define PrP sequence determinants that affect CWD transmission to humans. We engineered transgenic mice that express human PrP with four amino acid substitutions that result in expression of PrP with a β2-α2 loop (residues 165–175) that exactly matches that of elk PrP. Compared with transgenic mice expressing unaltered human PrP, mice expressing the human-elk chimeric PrP were highly susceptible to elk and deer CWD prions but were concurrently less susceptible to human Creutzfeldt-Jakob disease prions. A systematic in vitro survey of amino acid differences between humans and cervids identified two additional residues that impacted CWD conversion of human PrP. This work identifies amino acids that constitute a substantial structural barrier for CWD transmission to humans and helps illuminate the molecular requirements for cross-species prion transmission. PMID:25705888

  15. Characteristics of a four element gyromagnetic nonlinear transmission line array high power microwave source.

    PubMed

    Johnson, J M; Reale, D V; Krile, J T; Garcia, R S; Cravey, W H; Neuber, A A; Dickens, J C; Mankowski, J J

    2016-05-01

    In this paper, a solid-state four element array gyromagnetic nonlinear transmission line high power microwave system is presented as well as a detailed description of its subsystems and general output capabilities. This frequency agile S-band source is easily adjusted from 2-4 GHz by way of a DC driven biasing magnetic field and is capable of generating electric fields of 7.8 kV/m at 10 m correlating to 4.2 MW of RF power with pulse repetition frequencies up to 1 kHz. Beam steering of the array at angles of ±16.7° is also demonstrated, and the associated general radiation pattern is detailed. PMID:27250448

  16. Terminal contact elements of insect attachment devices studied by transmission X-ray microscopy.

    PubMed

    Eimüller, T; Guttmann, P; Gorb, S N

    2008-06-01

    For the first time, the terminal elements (spatulae) of setal (hairy) attachment devices of the beetle Gastrophysa viridula (Coleoptera, Chrysomelidae) and the fly Lucilia caesar (Diptera, Calliphoridae) were studied using transmission X-ray microscopy (TXM) with a lateral resolution of about 30 nm. Since images are taken under ambient conditions, we demonstrate here that this method can be applied to study the contact behaviour of biological systems, including animal tenent setae, in a fresh state. We observed that the attached spatulae show a viscoelastic behavior increasing the contact area and providing improved adaptability to the local topography of the surface. The technique can be extended to TXM tomography, which would provide three-dimensional information and a deeper insight into the details of insect attachment structures. PMID:18515726

  17. Characteristics of a four element gyromagnetic nonlinear transmission line array high power microwave source

    NASA Astrophysics Data System (ADS)

    Johnson, J. M.; Reale, D. V.; Krile, J. T.; Garcia, R. S.; Cravey, W. H.; Neuber, A. A.; Dickens, J. C.; Mankowski, J. J.

    2016-05-01

    In this paper, a solid-state four element array gyromagnetic nonlinear transmission line high power microwave system is presented as well as a detailed description of its subsystems and general output capabilities. This frequency agile S-band source is easily adjusted from 2-4 GHz by way of a DC driven biasing magnetic field and is capable of generating electric fields of 7.8 kV/m at 10 m correlating to 4.2 MW of RF power with pulse repetition frequencies up to 1 kHz. Beam steering of the array at angles of ±16.7° is also demonstrated, and the associated general radiation pattern is detailed.

  18. Unscrambling Mixed Elements using High Angle Annular Dark Field Scanning Transmission Electron Microscopy.

    PubMed

    van den Bos, Karel H W; De Backer, Annick; Martinez, Gerardo T; Winckelmans, Naomi; Bals, Sara; Nellist, Peter D; Van Aert, Sandra

    2016-06-17

    The development of new nanocrystals with outstanding physicochemical properties requires a full three-dimensional (3D) characterization at the atomic scale. For homogeneous nanocrystals, counting the number of atoms in each atomic column from high angle annular dark field scanning transmission electron microscopy images has been shown to be a successful technique to get access to this 3D information. However, technologically important nanostructures often consist of more than one chemical element. In order to extend atom counting to heterogeneous materials, a new atomic lensing model is presented. This model takes dynamical electron diffraction into account and opens up new possibilities for unraveling the 3D composition at the atomic scale. Here, the method is applied to determine the 3D structure of Au@Ag core-shell nanorods, but it is applicable to a wide range of heterogeneous complex nanostructures. PMID:27367396

  19. Vibration transmission through rolling element bearings. I - Bearing stiffness formulation. II - System studies

    NASA Technical Reports Server (NTRS)

    Lim, T. C.; Singh, R.

    1990-01-01

    How vibratory motion can be transmitted from the rotating shaft to the casing and other connecting structures in rotating mechanical equipment is addressed here by developing a new mathematical model of precision rolling element bearings. A new grating stiffness matrix is proposed in order to demonstrate a coupling between the shaft bending motion and the flexural motion of the casing plate. It is shown that the translational bearing stiffness coefficients currently used in rotor dynamic models are a small subset of the proposed matrix. The theory is validated by examples, and the proposed bearing formulation is then extended to demonstrate its superiority over existing models in vibration transmission analyses. It is shown that the model can easily be incorporated into analytical or numerical models typically used for dynamic analyses.

  20. Unscrambling Mixed Elements using High Angle Annular Dark Field Scanning Transmission Electron Microscopy

    NASA Astrophysics Data System (ADS)

    van den Bos, Karel H. W.; De Backer, Annick; Martinez, Gerardo T.; Winckelmans, Naomi; Bals, Sara; Nellist, Peter D.; Van Aert, Sandra

    2016-06-01

    The development of new nanocrystals with outstanding physicochemical properties requires a full three-dimensional (3D) characterization at the atomic scale. For homogeneous nanocrystals, counting the number of atoms in each atomic column from high angle annular dark field scanning transmission electron microscopy images has been shown to be a successful technique to get access to this 3D information. However, technologically important nanostructures often consist of more than one chemical element. In order to extend atom counting to heterogeneous materials, a new atomic lensing model is presented. This model takes dynamical electron diffraction into account and opens up new possibilities for unraveling the 3D composition at the atomic scale. Here, the method is applied to determine the 3D structure of Au@Ag core-shell nanorods, but it is applicable to a wide range of heterogeneous complex nanostructures.

  1. A hybrid finite element - statistical energy analysis approach to robust sound transmission modeling

    NASA Astrophysics Data System (ADS)

    Reynders, Edwin; Langley, Robin S.; Dijckmans, Arne; Vermeir, Gerrit

    2014-09-01

    When considering the sound transmission through a wall in between two rooms, in an important part of the audio frequency range, the local response of the rooms is highly sensitive to uncertainty in spatial variations in geometry, material properties and boundary conditions, which have a wave scattering effect, while the local response of the wall is rather insensitive to such uncertainty. For this mid-frequency range, a computationally efficient modeling strategy is adopted that accounts for this uncertainty. The partitioning wall is modeled deterministically, e.g. with finite elements. The rooms are modeled in a very efficient, nonparametric stochastic way, as in statistical energy analysis. All components are coupled by means of a rigorous power balance. This hybrid strategy is extended so that the mean and variance of the sound transmission loss can be computed as well as the transition frequency that loosely marks the boundary between low- and high-frequency behavior of a vibro-acoustic component. The method is first validated in a simulation study, and then applied for predicting the airborne sound insulation of a series of partition walls of increasing complexity: a thin plastic plate, a wall consisting of gypsum blocks, a thicker masonry wall and a double glazing. It is found that the uncertainty caused by random scattering is important except at very high frequencies, where the modal overlap of the rooms is very high. The results are compared with laboratory measurements, and both are found to agree within the prediction uncertainty in the considered frequency range.

  2. The architecture of cartilage: Elemental maps and scanning transmission ion microscopy/tomography

    NASA Astrophysics Data System (ADS)

    Reinert, Tilo; Reibetanz, Uta; Schwertner, Michael; Vogt, Jürgen; Butz, Tilman; Sakellariou, Arthur

    2002-04-01

    Articular cartilage is not just a jelly-like cover of the bone within the joints but a highly sophisticated architecture of hydrated macromolecules, collagen fibrils and cartilage cells. Influences on the physiological balance due to age-related or pathological changes can lead to malfunction and subsequently to degradation of the cartilage. Many activities in cartilage research are dealing with the architecture of joint cartilage but have limited access to elemental distributions. Nuclear microscopy is able to yield spatially resolved elemental concentrations, provides density information and can visualise the arrangement of the collagen fibres. The distribution of the cartilage matrix can be deduced from the elemental and density maps. The findings showed a varying content of collagen and proteoglycan between zones of different cell maturation. Zones of higher collagen content are characterised by aligned collagen fibres that can form tubular structures. Recently we focused on STIM tomography to investigate the three dimensional arrangement of the collagen structures.

  3. Application of the finite element method in the calculation of transmission loss of flat and curved panels

    NASA Astrophysics Data System (ADS)

    Koval, L. R.; Motamedi, S.; Ramakrishnan, J. V.

    1985-09-01

    This investigation represents an extension of a study of Roussos (1985) who considered the noise transmission loss of a rectangular plate in an infinite baffle. Roussos, who employed an analytical formulation, considered an unstiffened plate. While it is difficult to consider stiffeners by means of analytical methods, the difficulties can be avoided by employing a finite element procedure. For this reason, the present study is concerned with the implementation of a finite element method. The representation of the panel transmission loss is discussed, and the determination of the panel motion by means of the finite element technique is described, taking into account an isotropic flat panel, the exciting force, an eigenvalue problem, the radiation pressure, a plate element, and a cylindrical shell element. Numerical results are considered for a flat panel, a curved panel, and a stiffened flat panel.

  4. Laboratory activities involving transmissible spongiform encephalopathy causing agents

    PubMed Central

    Leunda, Amaya; Van Vaerenbergh, Bernadette; Baldo, Aline; Roels, Stefan; Herman, Philippe

    2013-01-01

    Since the appearance in 1986 of epidemic of bovine spongiform encephalopathy (BSE), a new form of neurological disease in cattle which also affected human beings, many diagnostic and research activities have been performed to develop detection and therapeutic tools. A lot of progress was made in better identifying, understanding and controlling the spread of the disease by appropriate monitoring and control programs in European countries. This paper reviews the recent knowledge on pathogenesis, transmission and persistence outside the host of prion, the causative agent of transmissible spongiform encephalopathies (TSE) in mammals with a particular focus on risk (re)assessment and management of biosafety measures to be implemented in diagnostic and research laboratories in Belgium. Also, in response to the need of an increasing number of European diagnostic laboratories stopping TSE diagnosis due to a decreasing number of TSE cases reported in the last years, decontamination procedures and a protocol for decommissioning TSE diagnostic laboratories is proposed. PMID:24055928

  5. Encoding Active Device Elements at Nanowire Tips.

    PubMed

    No, You-Shin; Gao, Ruixuan; Mankin, Max N; Day, Robert W; Park, Hong-Gyu; Lieber, Charles M

    2016-07-13

    Semiconductor nanowires and other one-dimensional materials are attractive for highly sensitive and spatially confined electrical and optical signal detection in biological and physical systems, although it has been difficult to localize active electronic or optoelectronic device function at one end of such one-dimensional structures. Here we report a new nanowire structure in which the material and dopant are modulated specifically at only one end of nanowires to encode an active two-terminal device element. We present a general bottom-up synthetic scheme for these tip-modulated nanowires and illustrate this with the synthesis of nanoscale p-n junctions. Electron microscopy imaging verifies the designed p-Si nanowire core with SiO2 insulating inner shell and n-Si outer shell with clean p-Si/n-Si tip junction. Electrical transport measurements with independent contacts to the p-Si core and n-Si shell exhibited a current rectification behavior through the tip and no detectable current through the SiO2 shell. Electrical measurements also exhibited an n-type response in conductance versus water-gate voltage with pulsed gate experiments yielding a temporal resolution of at least 0.1 ms and ∼90% device sensitivity localized to within 0.5 μm from the nanowire p-n tip. In addition, photocurrent experiments showed an open-circuit voltage of 0.75 V at illumination power of ∼28.1 μW, exhibited linear dependence of photocurrent with respect to incident illumination power with an estimated responsivity up to ∼0.22 A/W, and revealed localized photocurrent generation at the nanowire tip. The tip-modulated concept was further extended to a top-down/bottom-up hybrid approach that enabled large-scale production of vertical tip-modulated nanowires with a final synthetic yield of >75% with >4300 nanowires. Vertical tip-modulated nanowires were fabricated into >50 individually addressable nanowire device arrays showing diode-like current-voltage characteristics. These tip

  6. Transmission

    SciTech Connect

    Weismann, P.H.

    1991-01-29

    This paper describes an engagement mechanism. It comprises: a hollow shaft; an engagement outer rotatably mounted about the shaft and including an outer race; an engagement inner about the hollow shaft and angularly fixed relative thereto. The engagement inner including an inner race having central depressions with two inclined surfaces extending upwardly and outwardly in opposite directions from each the central depression; wedging elements between the inner race and the outer race; a cage between the inner race and the outer race, the cage retaining the wedging elements and being angularly movable relative to the inclined surfaces to selectively couple the engagement outer and the engagement inner through the wedging elements with either of the two inclined surfaces, the cage having a firs actuator portion; an actuator mounted in the hollow shaft and angularly fixed relative to the engagement inner. The actuator including a second actuator portion selectively engaging the first actuator portion to angularly displace the cage relative to the inclined surfaces for alignment of the wedging elements with the central depressions and selectively disengaging the first actuator portion to allow movement of the cage for movement of the wedging elements along the inclined surfaces to engage the outer race.

  7. Comparison of lumped-element and transmission-line models for thickness-shear-mode quartz resonator sensors

    SciTech Connect

    Cernosek, R.W.; Martin, S.J.; Hillman, A.R.

    1997-08-01

    Both a transmission-line model and its simpler variant, a lumped-element model, can be used to predict the responses of a thickness-shear-mode quartz resonator sensor. Relative deviations in the parameters computed by the two models (shifts in resonant frequency and motional resistance) do not exceed 3% for most practical sensor configurations operating at the fundamental resonance. If the ratio of the load surface mechanical impedance to the quartz shear characteristic impedance does not exceed 0.1, the lumped-element model always predicts responses within 1% of those for the transmission-line model.

  8. Highly active antiretroviral treatment for the prevention of HIV transmission

    PubMed Central

    2010-01-01

    In 2007 an estimated 33 million people were living with HIV; 67% resided in sub-Saharan Africa, with 35% in eight countries alone. In 2007, there were about 1.4 million HIV-positive tuberculosis cases. Globally, approximately 4 million people had been given highly active antiretroviral therapy (HAART) by the end of 2008, but in 2007, an estimated 6.7 million were still in need of HAART and 2.7 million more became infected with HIV. Although there has been unprecedented investment in confronting HIV/AIDS - the Joint United Nations Programme on HIV/AIDS estimates $13.8 billion was spent in 2008 - a key challenge is how to address the HIV/AIDS epidemic given limited and potentially shrinking resources. Economic disparities may further exacerbate human rights issues and widen the increasingly divergent approaches to HIV prevention, care and treatment. HIV transmission only occurs from people with HIV, and viral load is the single greatest risk factor for all modes of transmission. HAART can lower viral load to nearly undetectable levels. Prevention of mother to child transmission offers proof of the concept of HAART interrupting transmission, and observational studies and previous modelling work support using HAART for prevention. Although knowing one's HIV status is key for prevention efforts, it is not known with certainty when to start HAART. Building on previous modelling work, we used an HIV/AIDS epidemic of South African intensity to explore the impact of testing all adults annually and starting persons on HAART immediately after they are diagnosed as HIV positive. This theoretical strategy would reduce annual HIV incidence and mortality to less than one case per 1000 people within 10 years and it would reduce the prevalence of HIV to less than 1% within 50 years. To explore HAART as a prevention strategy, we recommend further discussions to explore human rights and ethical considerations, clarify research priorities and review feasibility and acceptability

  9. Vibration transmission through rolling element bearings in geared rotor system, part 1. Ph.D. Thesis Final Report

    NASA Technical Reports Server (NTRS)

    Singh, Rajendra; Lim, Teik Chin

    1989-01-01

    A mathematical model is proposed to examine the vibration transmission through rolling element bearings in geared rotor systems. Current bearing models, based on either ideal boundary conditions for the shaft or purely translational stiffness element description, cannot explain how the vibratory motion may be transmitted from the rotating shaft to the casing. This study clarifies this issue qualitatively and quantitatively by developing a comprehensive bearing stiffness matrix of dimension 6 model for the precision rolling element bearings from basic principles. The proposed bearing formulation is extended to analyze the overall geared rotor system dynamics including casing and mounts. The bearing stiffness matrix is included in discrete system models using lumped parameter and/or dynamic finite element techniques. Eigensolution and forced harmonic response due to rotating mass unbalance or kinematic transmission error excitation for a number of examples are computed.

  10. Modeling geomagnetically induced currents in the South African power transmission network using the finite element method

    NASA Astrophysics Data System (ADS)

    Matandirotya, Electdom; Cilliers, Pierre J.; Van Zyl, Robert R.

    2015-03-01

    Geomagnetically induced currents (GIC) are a result of time variations of the geomagnetic field, which induce a geoelectric field at the Earth's surface. Geomagnetic perturbations are enhanced during adverse space weather events called geomagnetic storms. All ground-based conductor networks can be affected by GIC during such events. As a way of assessing the magnitude of GIC expected in a particular technological system, models are developed, in which the computation of the induced geoelectric field is a key step. Computation of GIC in the South African power transmission network has so far been done using a uniform Earth model and improved using a layered Earth conductivity profile. In this work we present geoelectric field results obtained by using the finite element method (FEM) and improved GIC estimates using a realistic conductivity profile, magnetic field data interpolated from two South African observatories, and a new method for estimating the network coefficients, a and b, which map the north-south and east-west electric fields to their respective GIC components. The performance of the chosen FEM model demonstrates that it is an effective tool for GIC modeling. Unlike previous engineering techniques, our method for estimating the a and b coefficients from GIC and measured magnetic field data gives results that are independent of prior knowledge of the network configuration. The GIC estimated using the a and b coefficients obtained from the proposed method compares well with the measured GIC during the late October 2003 geomagnetic storm.

  11. Direct imaging of light elements by annular dark-field aberration-corrected scanning transmission electron microscopy

    SciTech Connect

    Lotnyk, Andriy Poppitz, David; Gerlach, Jürgen W.; Rauschenbach, Bernd

    2014-02-17

    In this report, we show that an annular dark-field detector in an aberration-corrected scanning transmission electron microscope allows the direct observation of light element columns in crystalline lattices. At specific imaging conditions, an enhancement of the intensities of light element columns in the presence of heavy element columns is observed. Experimental results are presented for imaging the nitrogen and carbon atomic columns at the GaN-SiC interface and within the GaN and SiC compounds. The crystal polarity of GaN at the interface is identified. The obtained findings are discussed and are well supported by image simulations.

  12. Simulation of bone-conducted sound transmission in a three-dimensional finite-element model of a human skull

    NASA Astrophysics Data System (ADS)

    Chang, You; Kim, Namkeun; Stenfelt, Stefan

    2015-12-01

    Bone conduction (BC) is the transmission of sound to the inner ear through the bones of the skull. This type of transmission is used in humans fitted with BC hearing aids as well as to classify between conductive and sensorineural hearing losses. The objective of the present study is to develop a finite-element (FE) model of the human skull based on cryosectional images of a female cadaver head in order to gain better understanding of the sound transmission. Further, the BC behavior was validated in terms of sound transmission against experimental data published in the literature. Results showed the responses of the simulated skull FE model were consistent with the experimentally reported data.

  13. Frequency translating phase conjugation circuit for active retrodirective antenna array. [microwave transmission

    NASA Technical Reports Server (NTRS)

    Chernoff, R. (Inventor)

    1980-01-01

    An active retrodirective antenna array which has central phasing from a reference antenna element through a "tree" structured network of transmission lines utilizes a number of phase conjugate circuits (PCCs) at each node and a phase reference regeneration circuit (PRR) at each node except the initial node. Each node virtually coincides with an element of the array. A PCC generates the exact conjugate phase of an incident signal using a phase locked loop which combines the phases in an up converter, divides the sum by 2 and mixes the result with the phase in a down converter for phase detection. The PRR extracts the phase from the conjugate phase. Both the PCC and the PRR are not only exact but also free from mixer degeneracy.

  14. Changes in pigment, spectral transmission and element content of pink chicken eggshells with different pigment intensity during incubation.

    PubMed

    Yu, Yue; Li, Zhanming; Pan, Jinming

    2016-01-01

    Objective. The objective of this study was to investigate changes in pigment, spectral transmission and element content of chicken eggshells with different intensities of pink pigment during the incubation period. We also investigated the effects of the region (small pole, equator and large pole) and pink pigment intensity of the chicken eggshell on the percent transmission of light passing through the chicken eggshells. Method. Eggs of comparable weight from a meat-type breeder (Meihuang) were used, and divided based on three levels of pink pigment (light, medium and dark) in the eggshells. During the incubation (0-21 d), the values of the eggshell pigment (ΔE, L (∗), a (∗), b (∗)) were measured. The percent transmission of light for different regions and intensities of eggshell pigmentation was measured by using the visible wavelength range of 380-780 nm. Result. Three measured indicators of eggshell color, ΔE, L (∗) and a (∗), did not change significantly during incubation. Compared with other regions and pigment intensities, eggshell at the small pole and with light pigmentation intensity showed the highest percent transmission of light. The transmission value varied significantly (P < 0.001) with incubation time. The element analysis of eggshells with different levels of pink pigment showed that the potassium content of the eggshells for all pigment levels decreased significantly during incubation. Conclusion. In summary, pigment intensity and the region of the eggshell influenced the percent transmission of light of eggshell. Differences in the spectral characteristics of different eggshells may influence the effects of photostimulation during the incubation of eggs. All of these results will be applicable for perfecting the design of light intensity for lighted incubation to improve productivity. PMID:27019785

  15. Changes in pigment, spectral transmission and element content of pink chicken eggshells with different pigment intensity during incubation

    PubMed Central

    Yu, Yue; Li, Zhanming

    2016-01-01

    Objective. The objective of this study was to investigate changes in pigment, spectral transmission and element content of chicken eggshells with different intensities of pink pigment during the incubation period. We also investigated the effects of the region (small pole, equator and large pole) and pink pigment intensity of the chicken eggshell on the percent transmission of light passing through the chicken eggshells. Method. Eggs of comparable weight from a meat-type breeder (Meihuang) were used, and divided based on three levels of pink pigment (light, medium and dark) in the eggshells. During the incubation (0–21 d), the values of the eggshell pigment (ΔE, L∗, a∗, b∗) were measured. The percent transmission of light for different regions and intensities of eggshell pigmentation was measured by using the visible wavelength range of 380–780 nm. Result. Three measured indicators of eggshell color, ΔE, L∗ and a∗, did not change significantly during incubation. Compared with other regions and pigment intensities, eggshell at the small pole and with light pigmentation intensity showed the highest percent transmission of light. The transmission value varied significantly (P < 0.001) with incubation time. The element analysis of eggshells with different levels of pink pigment showed that the potassium content of the eggshells for all pigment levels decreased significantly during incubation. Conclusion. In summary, pigment intensity and the region of the eggshell influenced the percent transmission of light of eggshell. Differences in the spectral characteristics of different eggshells may influence the effects of photostimulation during the incubation of eggs. All of these results will be applicable for perfecting the design of light intensity for lighted incubation to improve productivity. PMID:27019785

  16. Active pixel sensors with substantially planarized color filtering elements

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor); Kemeny, Sabrina E. (Inventor)

    1999-01-01

    A semiconductor imaging system preferably having an active pixel sensor array compatible with a CMOS fabrication process. Color-filtering elements such as polymer filters and wavelength-converting phosphors can be integrated with the image sensor.

  17. 78 FR 63974 - Enable Gas Transmission, LLC; Prior Notice of Activity Under Blanket Certificate

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-25

    ... Energy Regulatory Commission Enable Gas Transmission, LLC; Prior Notice of Activity Under Blanket Certificate On October 11, 2013, Enable Gas Transmission, LLC (Enable) filed with the Federal Energy..., Enable Gas Transmission, LLC, P.O. Box 21734, Shreveport, Louisiana 71151 or by calling...

  18. 78 FR 53742 - Columbia Gas Transmission, LLC; Prior Notice of Activity Under Blanket Certificate

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-30

    ... Energy Regulatory Commission Columbia Gas Transmission, LLC; Prior Notice of Activity Under Blanket Certificate On August 14, 2013, Columbia Gas Transmission, LLC (Columbia) filed with the Federal Energy... application may be directed to Fredric J. George, Senior Counsel, Columbia Gas Transmission, LLC, P.O....

  19. 75 FR 52519 - Columbia Gas Transmission, LLC; Prior Notice of Activity Under Blanket Certificate

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-26

    ... Energy Regulatory Commission Columbia Gas Transmission, LLC; Prior Notice of Activity Under Blanket Certificate August 19, 2010. On August 9, 2010, Columbia Gas Transmission, LLC (Columbia) filed with the... Fredric J. George, Senior Counsel, Columbia Gas Transmission, LLC, P.O. Box 1273, Charleston,...

  20. Active transmission isolation/rotor loads measurement system

    NASA Technical Reports Server (NTRS)

    Kenigsberg, I. J.; Defelice, J. J.

    1973-01-01

    Modifications were incorporated into a helicopter active transmission isolation system to provide the capability of utilizing the system as a rotor force measuring device. These included; (1) isolator redesign to improve operation and minimize friction, (2) installation of pressure transducers in each isolator, and (3) load cells in series with each torque restraint link. Full scale vibration tests performed during this study on a CH-53A helicopter airframe verified that these modifications do not degrade the systems wide band isolation characteristics. Bench tests performed on each isolator unit indicated that steady and transient loads can be measured to within 1 percent of applied load. Individual isolator vibratory load measurement accuracy was determined to be 4 percent. Load measurement accuracy was found to be independent of variations in all basic isolator operating characteristics. Full scale system load calibration tests on the CH-53A airframe established the feasibility of simultaneously providing wide band vibration isolation and accurate measurement of rotor loads. Principal rotor loads (lift, propulsive force, and torque) were measured to within 2 percent of applied load.

  1. Elements of active vibration control for rotating machinery

    NASA Technical Reports Server (NTRS)

    Ulbrich, Heinz

    1990-01-01

    The success or failure of active vibration control is determined by the availability of suitable actuators, modeling of the entire system including all active elements, positioning of the actuators and sensors, and implementation of problem-adapted control concepts. All of these topics are outlined and their special problems are discussed in detail. Special attention is given to efficient modeling of systems, especially for considering the active elements. Finally, design methods for and the application of active vibration control on rotating machinery are demonstrated by several real applications.

  2. Conformal optical elements for correcting wavefront distortions in YAG : Nd{sup 3+} active elements

    SciTech Connect

    Korolkov, V P; Nasyrov, R K; Poleshchuk, A G; Arapov, Yu D; Ivanov, A F

    2013-02-28

    Correction of the wavefront is studied for the light beam passing wide-aperture YAG : Nd3+ single-crystal rods, which are used as active elements in high-power solid-state lasers. A nonideal character of the crystal structure is responsible for the deformation of the wavefront of passing radiation. By using the halftone technology we have developed conformal aberration correctors capable of compensating rod nonuniformities and reducing the laser radiation divergence by an order of magnitude. The results obtained make it possible to employ optically nonuniform active elements in laser constructions. (laser optics 2012)

  3. Accuracy and stability of finite element schemes for the duct transmission problem

    NASA Technical Reports Server (NTRS)

    Astley, R. J.; Walkington, N. J.; Eversman, W.

    1981-01-01

    An investigation is conducted regarding the feasibility of approaches for improving the efficiency and stability of existing finite element method (FEM) schemes, taking into account both analytical and numerical studies. Of the four schemes considered for the 'steady' problem, the Hermitian Galerkin formulation appears to be the most efficient and therefore the most suitable scheme for futher full scale implementation. The Hermitian residual least squares (RLS) scheme although comparable in accuracy for the cases considered exhibits a slight tendency to cumulative errors. The performance of both the Lagrangian element schemes considered compares poorly with that of their Hermitian element counterparts. This is particularly true of the Lagrangian RLS scheme. The presence of internal oscillatory components is an inevitable consequence of all Galerkin schemes irrespective of element type.

  4. Evolutionary active transposable elements in the genome of the coelacanth.

    PubMed

    Chalopin, Domitille; Fan, Shaohua; Simakov, Oleg; Meyer, Axel; Schartl, Manfred; Volff, Jean-Nicolas

    2014-09-01

    The apparent morphological stasis in the lineage of the coelacanth, which has been called a "living fossil" by many, has been suggested to be causally related to a slow evolution of its genome, with strongly reduced activity of transposable elements (TEs). Analysis of the African coelacanth showed that at least 25% of its genome is constituted of transposable elements including retrotransposons, endogenous retroviruses and DNA transposons, with a strong predominance of non-Long Terminal Repeat (non-LTR) retrotransposons. The coelacanth genome has been shaped by four major general bursts of transposition during evolution, with major contributions of LINE1, LINE2, CR1, and Deu non-LTR retrotransposons. Many transposable elements are expressed in different tissues and might be active. The number of TE families in coelacanth, but also in lungfish, is lower than in teleost fish, but is higher than in chicken and human. This observation is in agreement with the hypothesis of a sequential elimination of many TE families in the sarcopterygian lineage during evolution. Taken together, our analysis indicates that the coelacanth contains more TE families than birds and mammals, and that these elements have been active during the evolution of the coelacanth lineage. Hence, at the level of transposable element activity, the coelacanth genome does not appear to evolve particularly slowly. PMID:23908136

  5. Investigation of coplanar strip dipole rectenna elements for microwave power transmission: simulation and experiment

    NASA Astrophysics Data System (ADS)

    Yang, Sang Yeol; Song, Kyo D.; Yoon, Hargsoon; Kim, Jaehwan

    2012-04-01

    The performance of dipole rectenna for microwave power transmission is very critical to the size and configuration of the dipole rectenna. Thus, it is important to verify the performance of dipole rectenna by comparing its performance in terms of simulation and experiment. This paper reports an experimental and computational investigation of coplanar strip (CPS) dipole rectenna for microwave power transmission. Rectenna consists of an antenna and a rectifier that involves a Schottky diode. CPS dipole antenna and rectenna are simulated using commercial software, so called Ansoft's HFSS and Designer. CPS dipole antenna as well as rectenna is fabricated on a copper coated polyimide substrate using an etching process. The characteristics of CPS dipole antenna are tested by using a pulse analyzer and spectrum analyzer under a 1.2 W microwave power incidence. Comparison of the simulation results with the experiments is made. The verified simulation approach for the CPS dipole rectenna will bring an effective design approach of rectennas for microwave power transmission.

  6. Regulation of ROS in transmissible gastroenteritis virus-activated apoptotic signaling

    SciTech Connect

    Ding, Li; Zhao, Xiaomin; Huang, Yong; Du, Qian; Dong, Feng; Zhang, Hongling; Song, Xiangjun; Zhang, Wenlong; Tong, Dewen

    2013-12-06

    Highlights: •TGEV infection induced ROS accumulation. •ROS accumulation is involved in TGEV-induced mitochondrial integrity impairment. •ROS is associated with p53 activation and apoptosis occurrence in TGEV-infected cells. -- Abstract: Transmissible gastroenteritis virus (TGEV), an enteropathogenic coronavirus, causes severe lethal watery diarrhea and dehydration in piglets. Previous studies indicate that TGEV infection induces cell apoptosis in host cells. In this study, we investigated the roles and regulation of reactive oxygen species (ROS) in TGEV-activated apoptotic signaling. The results showed that TGEV infection induced ROS accumulation, whereas UV-irradiated TGEV did not promote ROS accumulation. In addition, TGEV infection lowered mitochondrial transmembrane potential in PK-15 cell line, which could be inhibited by ROS scavengers, pyrrolidinedithiocarbamic (PDTC) and N-acetyl-L-cysteine (NAC). Furthermore, the two scavengers significantly inhibited the activation of p38 MAPK and p53 and further blocked apoptosis occurrence through suppressing the TGEV-induced Bcl-2 reduction, Bax redistribution, cytochrome c release and caspase-3 activation. These results suggest that oxidative stress pathway might be a key element in TGEV-induced apoptosis and TGEV pathogenesis.

  7. Finite-element model of the active organ of Corti.

    PubMed

    Ni, Guangjian; Elliott, Stephen J; Baumgart, Johannes

    2016-02-01

    The cochlear amplifier that provides our hearing with its extraordinary sensitivity and selectivity is thought to be the result of an active biomechanical process within the sensory auditory organ, the organ of Corti. Although imaging techniques are developing rapidly, it is not currently possible, in a fully active cochlea, to obtain detailed measurements of the motion of individual elements within a cross section of the organ of Corti. This motion is predicted using a two-dimensional finite-element model. The various solid components are modelled using elastic elements, the outer hair cells (OHCs) as piezoelectric elements and the perilymph and endolymph as viscous and nearly incompressible fluid elements. The model is validated by comparison with existing measurements of the motions within the passive organ of Corti, calculated when it is driven either acoustically, by the fluid pressure or electrically, by excitation of the OHCs. The transverse basilar membrane (BM) motion and the shearing motion between the tectorial membrane and the reticular lamina are calculated for these two excitation modes. The fully active response of the BM to acoustic excitation is predicted using a linear superposition of the calculated responses and an assumed frequency response for the OHC feedback. PMID:26888950

  8. A high transmission broadband gradient index lens using elastic shell acoustic metamaterial elements.

    PubMed

    Titovich, Alexey S; Norris, Andrew N; Haberman, Michael R

    2016-06-01

    The use of cylindrical elastic shells as elements in acoustic metamaterial devices is demonstrated through simulations and underwater measurements of a cylindrical-to-plane wave lens. Transformation acoustics of a circular region to a square dictate that the effective density in the lens remain constant and equal to that of water. Piecewise approximation to the desired effective compressibility is achieved using a square array with elements based on the elastic shell metamaterial concept developed by Titovich and Norris [J. Acoust. Soc. Am. 136(4), 1601-1609 (2014)]. The sizes of the elements are chosen based on availability of shells, minimizing fabrication difficulties. The tested device is neutrally buoyant comprising 48 elements of nine different types of commercial shells made from aluminum, brass, copper, and polymers. Simulations indicate a broadband range in which the device acts as a cylindrical to plane wave lens. The experimental findings confirm the broadband quadropolar response from approximately 20 to 40 kHz, with positive gain of the radiation pattern in the four plane wave directions. PMID:27369162

  9. Flux and dose transmission through concrete of neutrons from proton induced reactions on various target elements

    NASA Astrophysics Data System (ADS)

    Maiti, Moumita; Nandy, Maitreyee; Roy, S. N.; Sarkar, P. K.

    2004-12-01

    Simple empirical expressions for transmission of flux and dose through concrete are presented for neutrons from proton induced reactions. For this purpose the neutron emission from different targets in proton induced reactions in the energy range 25-200 MeV have been considered. The calculated effective dose outside a concrete shield shows overall good agreement with the effective dose estimated from measured neutron flux in the framework of the Moyer model. The calculated effective attenuation length shows a rising trend with incident proton energy and shield thickness.

  10. Slit2N Inhibits Transmission of HIV-1 from Dendritic Cells to T-cells by Modulating Novel Cytoskeletal Elements

    PubMed Central

    Shrivastava, Ashutosh; Prasad, Anil; Kuzontkoski, Paula M.; Yu, Jinlong; Groopman, Jerome E.

    2015-01-01

    Dendritic cells are among the first cells to encounter sexually acquired human immunodeficiency virus (HIV-1), in the mucosa, and they can transmit HIV-1 to CD4+ T-cells via an infectious synapse. Recent studies reveal that actin-rich membrane extensions establish direct contact between cells at this synapse and facilitate virus transmission. Genesis of these contacts involves signaling through c-Src and Cdc42, which modulate actin polymerization and filopodia formation via the Arp2/3 complex and Diaphanous 2 (Diaph2). We found that Slit2N, a ligand for the Roundabout (Robo) receptors, blocked HIV-1-induced signaling through Arp2/3 and Diaph2, decreased filopodial extensions on dendritic cells, and inhibited cell-to-cell transmission of HIV-1 in a Robo1-dependent manner. Employing proteomic analysis, we identified Flightless-1 as a novel, Robo1-interacting protein. Treatment with shRNAs reduced levels of Flightless-1 and demonstrated its role in efficient cell-to-cell transfer of HIV-1. These results suggest a novel strategy to limit viral infection in the host by targeting the Slit/Robo pathway with modulation of cytoskeletal elements previously unrecognized in HIV-1 transmission. PMID:26582347

  11. Slit2N Inhibits Transmission of HIV-1 from Dendritic Cells to T-cells by Modulating Novel Cytoskeletal Elements.

    PubMed

    Shrivastava, Ashutosh; Prasad, Anil; Kuzontkoski, Paula M; Yu, Jinlong; Groopman, Jerome E

    2015-01-01

    Dendritic cells are among the first cells to encounter sexually acquired human immunodeficiency virus (HIV-1), in the mucosa, and they can transmit HIV-1 to CD4(+) T-cells via an infectious synapse. Recent studies reveal that actin-rich membrane extensions establish direct contact between cells at this synapse and facilitate virus transmission. Genesis of these contacts involves signaling through c-Src and Cdc42, which modulate actin polymerization and filopodia formation via the Arp2/3 complex and Diaphanous 2 (Diaph2). We found that Slit2N, a ligand for the Roundabout (Robo) receptors, blocked HIV-1-induced signaling through Arp2/3 and Diaph2, decreased filopodial extensions on dendritic cells, and inhibited cell-to-cell transmission of HIV-1 in a Robo1-dependent manner. Employing proteomic analysis, we identified Flightless-1 as a novel, Robo1-interacting protein. Treatment with shRNAs reduced levels of Flightless-1 and demonstrated its role in efficient cell-to-cell transfer of HIV-1. These results suggest a novel strategy to limit viral infection in the host by targeting the Slit/Robo pathway with modulation of cytoskeletal elements previously unrecognized in HIV-1 transmission. PMID:26582347

  12. 78 FR 76827 - Midwestern Gas Transmission Company; Prior Notice of Activity Under Blanket Certificate

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-19

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Midwestern Gas Transmission Company; Prior Notice of Activity Under Blanket Certificate On December 4, 2013, Midwestern Gas Transmission Company (Midwestern) filed with the Federal Energy Regulatory Commission...

  13. Activity spread and breathers induced by finite transmission speeds in two-dimensional neural fields

    NASA Astrophysics Data System (ADS)

    Hutt, Axel; Rougier, Nicolas

    2010-11-01

    The work studies the spatiotemporal activity propagation in a two-dimensional spatial system involving a finite transmission speed. We derive a numerical scheme in detail to integrate the corresponding evolution equation and validate the derived algorithm by a study of a spatially periodic system. Finally, the work demonstrates numerically transmission delay-induced breathers subjected to anisotropic external input.

  14. 78 FR 30911 - Texas Eastern Transmission, LP; Prior Notice Activity Under Blanket Certificate

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-23

    ... Energy Regulatory Commission Texas Eastern Transmission, LP; Prior Notice Activity Under Blanket Certificate On May 8, 2013, Texas Eastern Transmission, LP (Texas Eastern), filed a prior notice request... Act, and Texas Eastern's blanket certificate issued in Docket No. CP82-535-000. Texas Eastern...

  15. Mechanics of dielectric elastomer-activated deformable transmission grating

    NASA Astrophysics Data System (ADS)

    Wang, Yin; Zhou, Jinxiong; Sun, Wenjie; Wu, Xiaohong; Zhang, Ling

    2014-09-01

    Laminating a thin layer of elastomeric grating on the surface of a prestretched dielectric elastomer (DE) membrane forms a basic design of electrically tunable transmission grating. We analyze the inhomogeneous deformation of a circular multiple-region configuration. Variation of the geometric and material parameters, as well as of the critical condition determined by loss of tension instability, is probed to aid the design of a DE-based deformable grating. The predicted changes in the grating period agree substantially with the experimental results reported by Aschwanden et al (Aschwanden et al 2007 IEEE Photon. Technol. Lett. 19 1090).

  16. P-glycoprotein ATPase activity requires lipids to activate a switch at the first transmission interface.

    PubMed

    Loo, Tip W; Clarke, David M

    2016-04-01

    P-glycoprotein (P-gp) is an ABC (ATP-Binding Cassette) drug pump. A common feature of ABC proteins is that they are organized into two wings. Each wing contains a transmembrane domain (TMD) and a nucleotide-binding domain (NBD). Drug substrates and ATP bind at the interface between the TMDs and NBDs, respectively. Drug transport involves ATP-dependent conformational changes between inward- (open, NBDs far apart) and outward-facing (closed, NBDs close together) conformations. P-gps crystallized in the presence of detergent show an open structure. Human P-gp is inactive in detergent but basal ATPase activity is restored upon addition of lipids. The lipids might cause closure of the wings to bring the NBDs close together to allow ATP hydrolysis. We show however, that cross-linking the wings together did not activate ATPase activity when lipids were absent suggesting that lipids may induce other structural changes required for ATPase activity. We then tested the effect of lipids on disulfide cross-linking of mutants at the first transmission interface between intracellular loop 4 (TMD2) and NBD1. Mutants L443C/S909C and L443C/R905C but not G471C/S909C and V472C/S909C were cross-linked with oxidant when in membranes. The mutants were then purified and cross-linked with or without lipids. Mutants G471C/S909C and V472C/S909C cross-linked only in the absence of lipids whereas mutants L443C/S909C and L443C/R905C were cross-linked only in the presence of lipids. The results suggest that lipids activate a switch at the first transmission interface and that the structure of P-gp is different in detergents and lipids. PMID:26944019

  17. Structural elements that underlie Doc2β function during asynchronous synaptic transmission.

    PubMed

    Xue, Renhao; Gaffaney, Jon D; Chapman, Edwin R

    2015-08-01

    Double C2-like domain-containing proteins alpha and beta (Doc2α and Doc2β) are tandem C2-domain proteins proposed to function as Ca(2+) sensors for asynchronous neurotransmitter release. Here, we systematically analyze each of the negatively charged residues that mediate binding of Ca(2+) to the β isoform. The Ca(2+) ligands in the C2A domain were dispensable for Ca(2+)-dependent translocation to the plasma membrane, with one exception: neutralization of D220 resulted in constitutive translocation. In contrast, three of the five Ca(2+) ligands in the C2B domain are required for translocation. Importantly, translocation was correlated with the ability of the mutants to enhance asynchronous release when overexpressed in neurons. Finally, replacement of specific Ca(2+)/lipid-binding loops of synaptotagmin 1, a Ca(2+) sensor for synchronous release, with corresponding loops from Doc2β, resulted in chimeras that yielded slower kinetics in vitro and slower excitatory postsynaptic current decays in neurons. Together, these data reveal the key determinants of Doc2β that underlie its function during the slow phase of synaptic transmission. PMID:26195798

  18. Structural elements that underlie Doc2β function during asynchronous synaptic transmission

    PubMed Central

    Xue, Renhao; Gaffaney, Jon D.; Chapman, Edwin R.

    2015-01-01

    Double C2-like domain-containing proteins alpha and beta (Doc2α and Doc2β) are tandem C2-domain proteins proposed to function as Ca2+ sensors for asynchronous neurotransmitter release. Here, we systematically analyze each of the negatively charged residues that mediate binding of Ca2+ to the β isoform. The Ca2+ ligands in the C2A domain were dispensable for Ca2+-dependent translocation to the plasma membrane, with one exception: neutralization of D220 resulted in constitutive translocation. In contrast, three of the five Ca2+ ligands in the C2B domain are required for translocation. Importantly, translocation was correlated with the ability of the mutants to enhance asynchronous release when overexpressed in neurons. Finally, replacement of specific Ca2+/lipid-binding loops of synaptotagmin 1, a Ca2+ sensor for synchronous release, with corresponding loops from Doc2β, resulted in chimeras that yielded slower kinetics in vitro and slower excitatory postsynaptic current decays in neurons. Together, these data reveal the key determinants of Doc2β that underlie its function during the slow phase of synaptic transmission. PMID:26195798

  19. Elemental distribution analysis of type I collagen fibrils in tilapia fish scale with energy-filtered transmission electron microscope.

    PubMed

    Okuda, Mitsuhiro; Takeguchi, Masaki; Tagaya, Motohiro; Tonegawa, Toru; Hashimoto, Ayako; Hanagata, Nobutaka; Ikoma, Toshiyuki

    2009-01-01

    Elemental distribution of calcium, phosphorus, oxygen, and carbon in a single collagen fibril obtained from tilapia fish scales was identified with an electron energy-loss spectroscopy and an energy-filtered transmission electron microscopy, for the first time. The carbon intensity profile of the single collagen fibril showed the specific D-periodic pattern at 67 nm of type I collagen fibrils. The calcium L(2,3)-edge and oxygen K-edge peak positions were detected at 347/350 eV and 137 eV, respectively, and these positions were identical to those of hydroxyapatite. Calcium, phosphorus, and oxygen were present in the hole zones as the amorphous phase, while carbon was present in the overlap zone. Our results indicated that the hole zones preferentially attract calcium and phosphate ions and thus serve as possible nucleation sites for mineralization. PMID:19419879

  20. Finite Element Development and Specifications of a Patched, Recessed Nomex Core Honeycomb Panel for Increased Sound Transmission Loss

    NASA Technical Reports Server (NTRS)

    Grosveld, Ferdinand W.

    2007-01-01

    This informal report summarizes the development and the design specifications of a recessed nomex core honeycomb panel in fulfillment of the deliverable in Task Order 13RBE, Revision 10, Subtask 17. The honeycomb panel, with 0.020-inch thick aluminum face sheets, has 0.016-inch thick aluminum patches applied to twenty-five, 6 by 6 inch, quarter inch thick recessed cores. A 10 dB higher transmission loss over the frequency range 250 - 1000 Hz was predicted by a MSC/NASTRAN finite element model when compared with the transmission loss of the base nomex core honeycomb panel. The static displacement, due to a unit force applied at either the core or recessed core area, was of the same order of magnitude as the static displacement of the base honeycomb panel when exposed to the same unit force. The mass of the new honeycomb design is 5.1% more than the base honeycomb panel. A physical model was constructed and is being tested.

  1. Modeling sound transmission of human middle ear and its clinical applications using finite element analysis.

    PubMed

    Chen, Shou-I; Lee, Ming-Hsiao; Yao, Chih-Min; Chen, Peir-Rong; Chou, Yuan-Fang; Liu, Tien-Chen; Song, Yu-Lin; Lee, Chia-Fone

    2013-03-01

    We have developed a new finite element (FE) model of human right ear, including the accurate geometry of middle ear ossicles, external ear canal, tympanic cavity, and mastoid cavity. The FE model would be suitable to study the dynamic behaviors of pathological middle ear conditions, including changes of stapedial ligament stiffness, tensor tympani ligament (TTL), and tympanic membrane (TM) stiffness and thickness. Increasing stiffness of stapedial ligament has substantial effect on stapes footplate movement, especially at low frequencies, but less effect on umbo movement. Softer TTL will result in increasing umbo and stapes footplate displacement, especially at low frequencies (f<1000Hz). When the TTL was detached, the vibration amplitude of umbo increased by 6dB at 600Hz and two peaks (300 and 600Hz) were found in the vibration amplitude of stapes footplate. Increasing the stiffness of tensor tympani resulted in a slightly decreased umbo amplitude at very low frequencies (f<500Hz) and significantly decreased displacement up to 12dB at middle frequencies (1000Hz1500Hz. As (TM) thickness was increased, the umbo displacement was reduced, especially at very low frequencies (f<600Hz). Otherwise, the stapes displacement was reduced at all frequencies. PMID:23465416

  2. Elemental analysis of sunflower cataract in Wilson's disease: a study using scanning transmission electron microscopy and energy dispersive spectroscopy.

    PubMed

    Jang, Hyo Ju; Kim, Joon Mo; Choi, Chul Young

    2014-04-01

    Signature ophthalmic characteristics of Wilson's disease (WD) are regarded as diagnostically important manifestations of the disease. Previous studies have proved the common occurrence of copper accumulation in the liver of patients with WD. However, in the case of sunflower cataracts, one of the rare diagnostic signs of WD, no study has demonstrated copper accumulation in the lens capsules of sunflower cataracts in WD patients. To investigate the nanostructure and elemental composition of sunflower cataracts in WD, transmission electron microscopy (TEM) was done on the capsulorhexised anterior lens capsule of sunflower cataracts in WD in order to evaluate anatomical variation and elemental changes. We utilized energy dispersive X-ray spectroscopy (EDS) to investigate the elemental composition of the lens capsule using both point and mapping spectroscopy. Quantitative analysis was performed for relative comparison of the elements. TEM showed the presence of granular deposits of varying size (20-350 nm), appearing mainly in the posterior one third of the anterior capsule. The deposits appeared in linear patterns with scattered dots. There were no electron-dense particles in the epithelial cell layer of the lens. Copper and sulfur peaks were consistently revealed in electron-dense granular deposits. In contrast, copper and sulfur peaks were absent in other tissues, including granule-free lens capsules and epithelial tissue. Most copper was exclusively located in clusters of electron-dense particles, and the copper distribution overlapped with sulfur on mapping spectroscopy. Quantitative analysis presented inconsistent ratios of copper to sulfur in each electron-dense granule. The mean ratio of copper to sulfur was about 3.25 (with a range of 2.39-3.78). This is the first elemental analysis of single electron particles in sunflower cataracts using EDS in the ophthalmic area. Sunflower cataracts with WD are assumed to be the result of accumulation of heterogeneous

  3. Unified active and reactive power modulation of HVDC transmission systems

    NASA Astrophysics Data System (ADS)

    Grund, C. E.; Pohl, R. V.

    1981-11-01

    The power modulation of a high voltage direct current (HVDC) system for stabilization of an ac/dc network was investigated. It was found that simultaneous modulation of both dc current and voltage was more effective than just current modulation by itself, since the dc voltage modulation could be used to minimize the reactive power changes resulting from a change of the dc current. This helps stabilize the ac busbar voltages at the converters, which reduces undesirable load flow changes to voltage dependent ac loads, thus improving the effectiveness of the dc power modulation. This unified modulation control concept was evaluated by means of digital computer studies as well as a special purpose HVDC simulator. Several combined ac/dc power transmission systems were synthesized for testing of different modulation controller concepts. An optimum controller design incorporating a linear quadratic control algorithm with full state feedback was first studied. This provided a basis for comparison of suboptimal controller designs utilizing reduced state feedback and a Kalman filter state reconstruction technique.

  4. Mobile insertion cassette elements found in small non-transmissible plasmids in Proteeae may explain qnrD mobilization.

    PubMed

    Guillard, Thomas; Grillon, Antoine; de Champs, Christophe; Cartier, Céline; Madoux, Janick; Berçot, Béatrice; Lebreil, Anne-Laure; Lozniewski, Alain; Riahi, Jacques; Vernet-Garnier, Véronique; Cambau, Emmanuelle

    2014-01-01

    qnrD is a plasmid mediated quinolone resistance gene from unknown origin, recently described in Enterobacteriaceae. It encodes a pentapeptide repeat protein 36-60% different from the other Qnr (A, B, C, S and VC). Since most qnrD-positive strains were described as strains belonging to Proteus or Providencia genera, we hypothesized that qnrD originated in Proteeae before disseminating to other enterobacterial species. We screened 317 strains of Proteeae for qnrD and its genetic support by PCR. For all the seven qnrD-positive strains (4 Proteus mirabilis, 1 Proteus vulgaris and 2 Providencia rettgeri) the gene was carried onto a small non-transmissible plasmid, contrarily to other qnr genes that are usually carried onto large multi-resistant plasmids. Nucleotide sequences of the qnrD-bearing plasmids were 96% identical. Plasmids contained 3 ORFs apart from qnrD and belonged to an undescribed incompatibility group. Only one plasmid, in P. vulgaris, was slightly different with a 1,568-bp insertion between qnrD and its promoter, leading to absence of quinolone resistance. We sought for similar plasmids in 15 reference strains of Proteeae, but which were tested negative for qnrD, and found a 48% identical plasmid (pVERM) in Providencia vermicola. In order to explain how qnrD could have been inserted into such native plasmid, we sought for gene mobilization structures. qnrD was found to be located within a mobile insertion cassette (mic) element which sequences are similar to one mic also found in pVERM. Our conclusions are that (i) the small non-transmissible qnrD-plasmids described here may result from the recombination between an as-yet-unknown progenitor of qnrD and pVERM, (ii) these plasmids are maintained in Proteeae being a qnrD reservoir (iii) the mic element may explain qnrD mobilization from non-transmissible plasmids to mobilizable or conjugative plasmids from other Enterobacteriaceae, (iv) they can recombined with larger multiresistant plasmids conjugated in

  5. VISUAL ELEMENTS OF SUBJECTIVE PREFERENCE MODULATE AMYGDALA ACTIVATION

    PubMed Central

    Bar, Moshe; Neta, Maital

    2010-01-01

    What are the basic visual cues that determine our preference towards mundane everyday objects? We previously showed that a highly potent cue is the nature of the object’s contour: people generally like objects with a curved contour compared with objects that have pointed features and a sharp-angled contour. This bias is hypothesized here to stem from an implicit perception of potential threat conveyed by sharp elements. Using human neuroimaging to test this hypothesis, we report that the amygdala, a brain structure that is involved in fear processing and has been shown to exhibit activation level that is proportional to arousal in general, is significantly more active for everyday sharp objects (e.g., a sofa with sharp corners) compared with their curved-contour counterparts. Therefore, our results indicate that a preference bias towards a visual object can be induced by low-level perceptual properties, independent of semantic meaning, via visual elements that on some level could be associated with threat. We further present behavioral results that provide initial support for the link between the sharpness of the contour and threat perception. Our brains might be organized to extract these basic contour elements rapidly for deriving an early warning signal in the presence of potential danger. PMID:17462678

  6. Transition Metals Catalyzed Element-Cyano Bonds Activations

    PubMed Central

    Wang, Rui; Falck, John R.

    2014-01-01

    Cyano group as a versatile functionalized intermediate has been explored for several decades, as it readily transfers to many useful functionalization groups such as amine, amide, acid, etc., which make it possess high popularization and use value in organic synthesis. Reactions involved with element-cyano bond cleavage can provide not only a new cyano group but also a freshly functionalized skeleton in one-pot, consequently making it of high importance. The highlights reviewed herein include H-CN, Si-CN, C-CN, B-CN, Sn-CN, Ge-CN, S-CN, Halo-CN, N-CN, and O-CN bonds cleavages and will summarize progress in such an important research area. This review article will focus on transition metal catalyzed reactions involving element-cyano bond activation. PMID:25558119

  7. Matching Element Symbols with State Abbreviations: A Fun Activity for Browsing the Periodic Table of Chemical Elements

    ERIC Educational Resources Information Center

    Woelk, Klaus

    2009-01-01

    A classroom activity is presented in which students are challenged to find matches between the United States two-letter postal abbreviations for states and chemical element symbols. The activity aims to lessen negative apprehensions students might have when the periodic table of the elements with its more than 100 combinations of letters is first…

  8. Asymmetry in Active SETI: A case for transmissions from Earth

    NASA Astrophysics Data System (ADS)

    Vakoch, Douglas A.

    2011-02-01

    The Search for Extraterrestrial Intelligence (SETI) typically presupposes contact with extraterrestrial civilizations much longer lived than humanity. Many have argued that given humanity's "youth," the burden of transmitting should be placed on the extraterrestrial civilizations, which presumably possess more advanced technologies. These assumptions have contributed to the current emphasis on Passive SETI. Complementing this existing stress on Passive SETI with an additional commitment to Active SETI, in which humankind transmits messages to other civilizations, would have several advantages, including (1) addressing the reality that regardless of whether older civilizations should be transmitting, they may not be transmitting; (2) placing the burden of decoding and interpreting messages on advanced extraterrestrials, which may facilitate mutual comprehension; and (3) signaling a move toward an intergenerational model of science with a long-term vision for benefiting other civilizations as well as future generations of humans. Technological requirements for Active SETI are considered, and a case is made for Active SETI as a means for experimentally testing variants of the Zoo Hypothesis. Recommendations are provided for sustaining Passive and Active SETI and the communities that conduct these searches.

  9. PPARγ Activation Attenuates Opioid Consumption and Modulates Mesolimbic Dopamine Transmission

    PubMed Central

    de Guglielmo, Giordano; Melis, Miriam; De Luca, Maria Antonietta; Kallupi, Marsida; Li, Hong Wu; Niswender, Kevin; Giordano, Antonio; Senzacqua, Martina; Somaini, Lorenzo; Cippitelli, Andrea; Gaitanaris, George; Demopulos, Gregory; Damadzic, Ruslan; Tapocik, Jenica; Heilig, Markus; Ciccocioppo, Roberto

    2015-01-01

    PPARγ is one of the three isoforms identified for the peroxisome proliferator-activated receptors (PPARs) and is the receptor for the thiazolidinedione class of anti-diabetic medications including pioglitazone. PPARγ has been long studied for its role in adipogenesis and glucose metabolism, but the discovery of the localization in ventral tegmental area (VTA) neurons opens new vistas for a potential role in the regulation of reward processing and motivated behavior in drug addiction. Here, we demonstrate that activation of PPARγ by pioglitazone reduces the motivation for heroin and attenuates its rewarding properties. These effects are associated with a marked reduction of heroin-induced increase in phosphorylation of DARPP-32 protein in the nucleus accumbens (NAc) and with a marked and selective reduction of acute heroin-induced elevation of extracellular dopamine (DA) levels in the NAc shell, as measured by in vivo microdialysis. Through ex vivo electrophysiology in acute midbrain slices, we also show that stimulation of PPARγ attenuates opioid-induced excitation of VTA DA neurons via reduction of presynaptic GABA release from the rostromedial tegmental nucleus (RMTg). Consistent with this finding, site-specific microinjection of pioglitazone into the RMTg but not into the VTA reduced heroin taking. Our data illustrate that activation of PPARγ may represent a new pharmacotherapeutic option for the treatment of opioid addiction. PMID:25311134

  10. Active control of multi-element rotor blade airfoils

    NASA Technical Reports Server (NTRS)

    Torok, Michael S. (Inventor); Moffitt, Robert C. (Inventor); Bagai, Ashish (Inventor)

    2005-01-01

    A multi-element rotor blade includes an individually controllable main element and fixed aerodynamic surface in an aerodynamically efficient location relative to the main element. The main element is controlled to locate the fixed aerodynamic surface in a position to increase lift and/or reduce drag upon the main element at various azimuthal positions during rotation.

  11. Nuclear Thermal Rocket Element Environmental Simulator (NTREES) Upgrade Activities

    NASA Technical Reports Server (NTRS)

    Emrich, William J., Jr.

    2014-01-01

    Over the past year the Nuclear Thermal Rocket Element Environmental Simulator (NTREES) has been undergoing a significant upgrade beyond its initial configuration. The NTREES facility is designed to perform realistic non-nuclear testing of nuclear thermal rocket (NTR) fuel elements and fuel materials. Although the NTREES facility cannot mimic the neutron and gamma environment of an operating NTR, it can simulate the thermal hydraulic environment within an NTR fuel element to provide critical information on material performance and compatibility. The first phase of the upgrade activities which was completed in 2012 in part consisted of an extensive modification to the hydrogen system to permit computer controlled operations outside the building through the use of pneumatically operated variable position valves. This setup also allows the hydrogen flow rate to be increased to over 200 g/sec and reduced the operation complexity of the system. The second stage of modifications to NTREES which has just been completed expands the capabilities of the facility significantly. In particular, the previous 50 kW induction power supply has been replaced with a 1.2 MW unit which should allow more prototypical fuel element temperatures to be reached. The water cooling system was also upgraded to so as to be capable of removing 100% of the heat generated during. This new setup required that the NTREES vessel be raised onto a platform along with most of its associated gas and vent lines. In this arrangement, the induction heater and water systems are now located underneath the platform. In this new configuration, the 1.2 MW NTREES induction heater will be capable of testing fuel elements and fuel materials in flowing hydrogen at pressures up to 1000 psi at temperatures up to and beyond 3000 K and at near-prototypic reactor channel power densities. NTREES is also capable of testing potential fuel elements with a variety of propellants, including hydrogen with additives to inhibit

  12. Cocaine facilitates glutamatergic transmission and activates lateral habenular neurons.

    PubMed

    Zuo, Wanhong; Chen, Lixin; Wang, Liwei; Ye, Jiang-Hong

    2013-07-01

    Cocaine administration can be both rewarding and aversive. While much effort has gone to investigating the rewarding effect, the mechanisms underlying cocaine-induced aversion remain murky. There is increasing evidence that the lateral habenula (LHb), a small epithalamic structure, plays a critical role in the aversive responses of many addictive drugs including cocaine. However, the effects of cocaine on LHb neurons are not well explored. Here we show that, in acute brain slices from rats, cocaine depolarized LHb neurons and accelerated their spontaneous firing. The AMPA and NMDA glutamate receptor antagonists, 6, 7-dinitroquinoxaline-2, 3-dione, DL-2-amino-5-phosphono-valeric acid, attenuated cocaine-induced acceleration. In addition, cocaine concentration-dependently enhanced glutamatergic excitation: enhanced the amplitude but reduced the paired pulse ratio of EPSCs elicited by electrical stimulations, and increased the frequency of spontaneous EPSCs in the absence and presence of tetrodotoxin. Dopamine and the agonists of dopamine D1 (SKF 38393) and D2 (quinpirole) receptors, as well as the dopamine transporter blocker (GBR12935), mimicked the effects of cocaine. Conversely, both D1 (SKF83566) and D2 (raclopride) antagonists substantially attenuated cocaine's effects on EPSCs and firing. Together, our results provide evidence that cocaine may act primarily via an increase in dopamine levels in the LHb that activates both D1 and D2 receptors. This leads to an increase in presynaptic glutamate release probability and LHb neuron activity. This may contribute to the aversive effect of cocaine observed in vivo. PMID:23347950

  13. Monitoring transmission routes of Listeria spp. in smoked salmon production with repetitive element sequence-based PCR techniques.

    PubMed

    Zunabovic, M; Domig, K J; Pichler, I; Kneifel, W

    2012-03-01

    Various techniques have been used for tracing the transmission routes of Listeria species and for the assessment of hygiene standards in food processing plants. The potential of repetitive element sequence-based PCR (Rep-PCR) methods (GTG₅ and REPI + II) for the typing of Listeria isolates (n = 116), including Listeria monocytogenes (n = 46), was evaluated in a particular situation arising from the relocation of a company producing cold-smoked salmon. Pulsed-field gel electrophoresis (PFGE) using three restriction enzymes (ApaI, AscI, and SmaI) was used for comparison. Identical transmission scenarios among two companies could be identified by cluster analysis of L. monocytogenes isolates that were indistinguishable by both Rep-PCR and PFGE. The calculated diversity index (DI) indicates that Rep-PCR subtyping of Listeria species with primer sets GTG₅ and REPI + II has a lower discrimination power than does PFGE. When concatenated Rep-PCR cluster analysis was used, the DI increased from 0.934 (REPI + II) and 0.923 (GTG₅) to 0.956. The discrimination power of this method was similar to that of PFGE typing based on restriction enzyme Apa I (DI = 0.955). Listeria welshimeri may be useful as an indicator for monitoring smoked salmon processing environments. Rep-PCR meets the expectations of a reasonable, fast, and low-cost molecular subtyping method for the routine monitoring of Listeria species. The discriminatory power as characterized by the DI sufficiently quantifies the probability of unrelated isolates being characterized as different subtypes. Therefore, Rep-PCR typing based on two primer systems (GTG₅ and REPI + II) may be a useful tool for monitoring industrial hygiene. PMID:22410224

  14. A Hands-On Activity to Introduce the Effects of Transmission by an Invasive Species

    ERIC Educational Resources Information Center

    May, Barbara Jean

    2013-01-01

    This activity engages students to better understand the impact of transmission by invasive species. Using dice, poker chips, and paper plates, an entire class mimics the spread of an invasive species within a geographic region. The activity can be modified and conducted at the K-16 levels.

  15. Tempo and Mode of Transposable Element Activity in Drosophila

    PubMed Central

    Kofler, Robert; Nolte, Viola; Schlötterer, Christian

    2015-01-01

    The evolutionary dynamics of transposable element (TE) insertions have been of continued interest since TE activity has important implications for genome evolution and adaptation. Here, we infer the transposition dynamics of TEs by comparing their abundance in natural D. melanogaster and D. simulans populations. Sequencing pools of more than 550 South African flies to at least 320-fold coverage, we determined the genome wide TE insertion frequencies in both species. We suggest that the predominance of low frequency insertions in the two species (>80% of the insertions have a frequency <0.2) is probably due to a high activity of more than 58 families in both species. We provide evidence for 50% of the TE families having temporally heterogenous transposition rates with different TE families being affected in the two species. While in D. melanogaster retrotransposons were more active, DNA transposons showed higher activity levels in D. simulans. Moreover, we suggest that LTR insertions are mostly of recent origin in both species, while DNA and non-LTR insertions are older and more frequently vertically transmitted since the split of D. melanogaster and D. simulans. We propose that the high TE activity is of recent origin in both species and a consequence of the demographic history, with habitat expansion triggering a period of rapid evolution. PMID:26186437

  16. Hippocampal cannabinoid transmission modulates dopamine neuron activity: impact on rewarding memory formation and social interaction.

    PubMed

    Loureiro, Michael; Renard, Justine; Zunder, Jordan; Laviolette, Steven R

    2015-05-01

    Disturbances in cannabinoid type 1 receptor (CB1R) signaling have been linked to emotional and cognitive deficits characterizing neuropsychiatric disorders, including schizophrenia. Thus, there is growing interest in characterizing the relationship between cannabinoid transmission, emotional processing, and dopamine (DA)-dependent behavioral deficits. The CB1R is highly expressed in the mammalian nervous system, particularly in the hippocampus. Activation of the ventral hippocampal subregion (vHipp) is known to increase both the activity of DAergic neurons located in the ventral tegmental area (VTA) and DA levels in reward-related brain regions, particularly the nucleus accumbens (NAc). However, the possible functional relationship between hippocampal CB1R transmission and VTA DA neuronal activity is not currently understood. In this study, using in vivo neuronal recordings in rats, we demonstrate that activation of CB1R in the vHipp strongly increases VTA DA neuronal firing and bursting activity, while simultaneously decreasing the activity of VTA non-DA neurons. Furthermore, using a conditioned place preference procedure and a social interaction test, we report that intra-vHipp CB1R activation potentiates the reward salience of normally sub-threshold conditioning doses of opiates and induces deficits in natural sociability and social recognition behaviors. Finally, these behavioral effects were prevented by directly blocking NAc DAergic transmission. Collectively, these findings identify hippocampal CB1R transmission as a critical modulator of the mesolimbic DA pathway and in the processing of reward and social-related behavioral phenomena. PMID:25510937

  17. Activity Level-Dependent Synapse-Specific AMPA Receptor Trafficking Regulates Transmission Kinetics

    PubMed Central

    Zhu, J. Julius

    2009-01-01

    Central glutamatergic synapses may express AMPA-sensitive glutamate receptors (AMPA-Rs) with distinct gating properties and exhibit different transmission dynamics, which are important for computing various synaptic inputs received at different populations of synapses. However, how glutamatergic synapses acquire AMPA-Rs with distinct kinetics to influence synaptic integration remains poorly understood. Here I report synapse-specific trafficking of distinct AMPA-Rs in rat cortical layer 4 stellate and layer 5 pyramidal neurons. The analysis indicates that in single layer 4 stellate neurons thalamocortical synapses generate faster synaptic responses than intracortical synapses. Moreover, GluR1-containing AMPA-Rs traffic selectively into intracortical synapses, and this process requires sensory experience-dependent activity and slows down transmission kinetics. GluR4-containing AMPA-Rs traffic more heavily into thalamocortical synapses than intracortical synapses, and this process requires spontaneous synaptic activity and speeds up transmission kinetics. GluR2-containing AMPA-Rs traffic equally into both thalamocortical and intracortical synapses, and this process requires no synaptic activity and resets transmission kinetics. Notably, synaptic trafficking of distinct AMPA-Rs differentially regulates synaptic integration. Thus, synapse-specific AMPA-R trafficking coarsely sets and synaptic activity finely tunes transmission kinetics and integration properties at different synapses in central neurons. PMID:19439609

  18. Real-time transposable element activity in individual live cells

    PubMed Central

    Lee, Gloria; Martini, K. Michael

    2016-01-01

    The excision and reintegration of transposable elements (TEs) restructure their host genomes, generating cellular diversity involved in evolution, development, and the etiology of human diseases. Our current knowledge of TE behavior primarily results from bulk techniques that generate time and cell ensemble averages, but cannot capture cell-to-cell variation or local environmental and temporal variability. We have developed an experimental system based on the bacterial TE IS608 that uses fluorescent reporters to directly observe single TE excision events in individual cells in real time. We find that TE activity depends upon the TE’s orientation in the genome and the amount of transposase protein in the cell. We also find that TE activity is highly variable throughout the lifetime of the cell. Upon entering stationary phase, TE activity increases in cells hereditarily predisposed to TE activity. These direct observations demonstrate that real-time live-cell imaging of evolution at the molecular and individual event level is a powerful tool for the exploration of genome plasticity in stressed cells. PMID:27298350

  19. Real-time transposable element activity in individual live cells.

    PubMed

    Kim, Neil H; Lee, Gloria; Sherer, Nicholas A; Martini, K Michael; Goldenfeld, Nigel; Kuhlman, Thomas E

    2016-06-28

    The excision and reintegration of transposable elements (TEs) restructure their host genomes, generating cellular diversity involved in evolution, development, and the etiology of human diseases. Our current knowledge of TE behavior primarily results from bulk techniques that generate time and cell ensemble averages, but cannot capture cell-to-cell variation or local environmental and temporal variability. We have developed an experimental system based on the bacterial TE IS608 that uses fluorescent reporters to directly observe single TE excision events in individual cells in real time. We find that TE activity depends upon the TE's orientation in the genome and the amount of transposase protein in the cell. We also find that TE activity is highly variable throughout the lifetime of the cell. Upon entering stationary phase, TE activity increases in cells hereditarily predisposed to TE activity. These direct observations demonstrate that real-time live-cell imaging of evolution at the molecular and individual event level is a powerful tool for the exploration of genome plasticity in stressed cells. PMID:27298350

  20. A Hyperactive Transposase of the Maize Transposable Element Activator (Ac)

    PubMed Central

    Lazarow, Katina; Du, My-Linh; Weimer, Ruth; Kunze, Reinhard

    2012-01-01

    Activator/Dissociation (Ac/Ds) transposable elements from maize are widely used as insertional mutagenesis and gene isolation tools in plants and more recently also in medaka and zebrafish. They are particularly valuable for plant species that are transformation-recalcitrant and have long generation cycles or large genomes with low gene densities. Ac/Ds transposition frequencies vary widely, however, and in some species they are too low for large-scale mutagenesis. We discovered a hyperactive Ac transposase derivative, AcTPase4x, that catalyzes in the yeast Saccharomyces cerevisiae 100-fold more frequent Ds excisions than the wild-type transposase, whereas the reintegration frequency of excised Ds elements is unchanged (57%). Comparable to the wild-type transposase in plants, AcTPase4x catalyzes Ds insertion preferentially into coding regions and to genetically linked sites, but the mutant protein apparently has lost the weak bias of the wild-type protein for insertion sites with elevated guanine–cytosine content and nonrandom protein-DNA twist. AcTPase4x exhibits hyperactivity also in Arabidopsis thaliana where it effects a more than sixfold increase in Ds excision relative to wild-type AcTPase and thus may be useful to facilitate Ac/Ds-based insertion mutagenesis approaches. PMID:22562933

  1. Re-active Passive (RAP) Devices for Control of Noise Transmission through a Panel

    NASA Technical Reports Server (NTRS)

    Carneal, James P.; Giovanardi, Marco; Fuller, Chris R.; Palumbo, Daniel L.

    2008-01-01

    Re-Active Passive (RAP) devices have been developed to control low frequency (<1000 Hz) noise transmission through a panel. These devices use a combination of active, re-active, and passive technologies packaged into a single unit to control a broad frequency range utilizing the strength of each technology over its best suited frequency range. The RAP device uses passive constrained layer damping to cover the relatively high frequency range (>200 Hz), reactive distributed vibration absorber) to cover the medium frequency range (75 to 250 Hz), and active control for controlling low frequencies (<200 Hz). The device was applied to control noise transmission through a panel mounted in a transmission loss test facility. Experimental results are presented for the bare panel, and combinations of passive treatment, reactive treatment, and active control. Results indicate that three RAP devices were able to increase the overall broadband (15-1000 Hz) transmission loss by 9.4 dB. These three devices added a total of 285 grams to the panel mass of 6.0 kg, or approximately 5%, not including control electronics.

  2. Neutron activation analysis; A sensitive test for trace elements

    SciTech Connect

    Hossain, T.Z. . Ward Lab.)

    1992-01-01

    This paper discusses neutron activation analysis (NAA), an extremely sensitive technique for determining the elemental constituents of an unknown specimen. Currently, there are some twenty-five moderate-power TRIGA reactors scattered across the United States (fourteen of them at universities), and one of their principal uses is for NAA. NAA is procedurally simple. A small amount of the material to be tested (typically between one and one hundred milligrams) is irradiated for a period that varies from a few minutes to several hours in a neutron flux of around 10{sup 12} neutrons per square centimeter per second. A tiny fraction of the nuclei present (about 10{sup {minus}8}) is transmuted by nuclear reactions into radioactive forms. Subsequently, the nuclei decay, and the energy and intensity of the gamma rays that they emit can be measured in a gamma-ray spectrometer.

  3. 75 FR 7474 - CenterPoint Energy Gas Transmission Company; Prior Notice of Activity Under Blanket Certificate

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-19

    ... Energy Regulatory Commission CenterPoint Energy Gas Transmission Company; Prior Notice of Activity Under Blanket Certificate February 3, 2010. On January 26, 2010 CenterPoint Energy Gas Transmission Company... & Compliance, CenterPoint Energy Gas Transmission Company, P.O. Box 21734, Shreveport, Louisiana 71151, or...

  4. Transmission of whole-body vibration and its effect on muscle activation.

    PubMed

    Tankisheva, Ekaterina; Jonkers, Ilse; Boonen, Steven; Delecluse, Christophe; van Lenthe, G Harry; Druyts, Hans L J; Spaepen, Pieter; Verschueren, Sabine M P

    2013-09-01

    The aim of current study was to measure the transmission of whole-body vibration through the entire body and to relate this to body posture and induced muscular activation. Eight clinically healthy subjects performed 3 static body postures-high squat (135°), deep squat (110°), and erect stance, whereas vibration transmission was assessed over a wide range of accelerations (from 0.33 to 7.98 g) and frequencies (from 30 to 50 Hz). To assess the vibration transmission, 9 triaxial accelerometers were attached from the ankle up to the head and the root mean square of acceleration signal of each site-specific body point was calculated. Additionally, muscle activity from 7 lower limb muscles was recorded. The results showed a significant attenuation of the platform accelerations transmitted from the feet to the head. Compared with erect stance, knee bent posture significantly diminished vibration transmission at the hip, spine, and the head (p < 0.05). Vibration transmission to the spine was significantly lower in deep vs. high squat (p < 0.05), suggesting that further knee bending may reduce the risk of overloading the spine. Vibration increased the muscle activity in most leg and hip muscles during both squat postures, although, on average, no clear dose-response relationship between the acceleration and/or frequency and muscle response was found. The muscular activation of vastus medialis and rectus femoris showed clear negative correlation to the vibration transmission at the sternum. The specific vibration parameters used in the present study can be considered as safe and suitable for a training program. Moreover, the present results contribute to optimize the most advantageous whole-body vibration protocol and to determine the beneficial effects on muscle and bone. PMID:23222086

  5. Traveling-wave pulse on a superconductive active transmission line using resonant tunneling diodes

    NASA Astrophysics Data System (ADS)

    Klofaï, Yerima; Essimbi, B. Z.; Jäger, D.

    2013-10-01

    Analytic study and computer experiment investigations on a superconductive active transmission line using resonant tunneling diodes (RTDs) are discussed. It is shown, based on nonlinear wave propagation effects, that the line supports pulse propagation appearing as pairs of kink-antikink profiles. This behavior is due to compensation between the effects of amplification and dissipation along the network.

  6. Follistatin-like 1 suppresses sensory afferent transmission by activating Na+,K+-ATPase.

    PubMed

    Li, Kai-Cheng; Zhang, Fang-Xiong; Li, Chang-Lin; Wang, Feng; Yu, Ming-Yan; Zhong, Yan-Qing; Zhang, Kai-Hua; Lu, Ying-Jin; Wang, Qiong; Ma, Xiao-Li; Yao, Jun-Ru; Wang, Jin-Yuan; Lin, Li-Bo; Han, Mei; Zhang, Yu-Qiu; Kuner, Rohini; Xiao, Hua-Sheng; Bao, Lan; Gao, Xiang; Zhang, Xu

    2011-03-10

    Excitatory synaptic transmission is modulated by inhibitory neurotransmitters and neuromodulators. We found that the synaptic transmission of somatic sensory afferents can be rapidly regulated by a presynaptically secreted protein, follistatin-like 1 (FSTL1), which serves as a direct activator of Na(+),K(+)-ATPase (NKA). The FSTL1 protein is highly expressed in small-diameter neurons of the dorsal root ganglion (DRG). It is transported to axon terminals via small translucent vesicles and secreted in both spontaneous and depolarization-induced manners. Biochemical assays showed that FSTL1 binds to the α1 subunit of NKA and elevates NKA activity. Extracellular FSTL1 induced membrane hyperpolarization in cultured cells and inhibited afferent synaptic transmission in spinal cord slices by activating NKA. Genetic deletion of FSTL1 in small DRG neurons of mice resulted in enhanced afferent synaptic transmission and sensory hypersensitivity, which could be reduced by intrathecally applied FSTL1 protein. Thus, FSTL1-dependent activation of NKA regulates the threshold of somatic sensation. PMID:21382556

  7. Increased prevalence of carbapenem resistant Enterobacteriaceae in hospital setting due to cross-species transmission of the bla NDM-1 element and clonal spread of progenitor resistant strains.

    PubMed

    Wang, Xuan; Chen, Gongxiang; Wu, Xiaoyan; Wang, Liangping; Cai, Jiachang; Chan, Edward W; Chen, Sheng; Zhang, Rong

    2015-01-01

    This study investigated the transmission characteristics of carbapenem-resistant Enterobacteriaceae (CRE) strains collected from a hospital setting in China, in which consistent emergence of CRE strains were observable during the period of May 2013 to February 2014. Among the 45 CRE isolates tested, 21 (47%) strains were found to harbor the bla NDM-1 element, and the rest of 24 CRE strains were all positive for bla KPC-2. The 21 bla NDM-1-borne strains were found to comprise multiple Enterobacteriaceae species including nine Enterobacter cloacae, three Escherichia coli, three Citrobacter freundii, two Klebsiella pneumoniae, two Klebsiella oxytoca, and two Morganella morganii strains, indicating that cross-species transmission of bla NDM-1 is a common event. Genetic analyses by PFGE and MLST showed that, with the exception of E. coli and E. cloacae, strains belonging to the same species were often genetically unrelated. In addition to bla NDM-1, several CRE strains were also found to harbor the bla KPC-2, bla VIM-1, and bla IMP-4 elements. Conjugations experiments confirmed that the majority of carbapenem resistance determinants were transferable. Taken together, our findings suggest that transmission of mobile resistance elements among members of Enterobacteriaceae and clonal spread of CRE strains may contribute synergistically to a rapid increase in the population of CRE in clinical settings, prompting a need to implement more rigorous infection control measures to arrest such vicious transmission cycle in CRE-prevalent areas. PMID:26136735

  8. Assessment of nose protector for sport activities: finite element analysis.

    PubMed

    Coto, Neide Pena; Meira, Josete Barbosa Cruz; Brito e Dias, Reinaldo; Driemeier, Larissa; de Oliveira Roveri, Guilherme; Noritomi, Pedro Yoshito

    2012-04-01

    There has been a significant increase in the number of facial fractures stemming from sport activities in recent years, with the nasal bone one of the most affected structures. Researchers recommend the use of a nose protector, but there is no standardization regarding the material employed. Clinical experience has demonstrated that a combination of a flexible and rigid layer of ethylene vinyl acetate (EVA) offers both comfort and safety to practitioners of sports. The aim of the present study was the investigation into the stresses generated by the impact of a rigid body on the nasal bone on models with and without an EVA protector. For such, finite element analysis was employed. A craniofacial model was constructed from images obtained through computed tomography. The nose protector was modeled with two layers of EVA (1 mm of rigid EVA over 2 mm of flexible EVA), following the geometry of the soft tissue. Finite element analysis was performed using the LS Dyna program. The bone and rigid EVA were represented as elastic linear material, whereas the soft tissues and flexible EVA were represented as hyperelastic material. The impact from a rigid sphere on the frontal region of the face was simulated with a constant velocity of 20 m s(-1) for 9.1 μs. The model without the protector served as the control. The distribution of maximal stress of the facial bones was recorded. The maximal stress on the nasal bone surpassed the breaking limit of 0.13-0.34 MPa on the model without a protector, while remaining below this limit on the model with the protector. Thus, the nose protector made from both flexible and rigid EVA proved effective at protecting the nasal bones under high-impact conditions. PMID:21790992

  9. Plasticity of Neuron-Glial Transmission: Equipping Glia for Long-Term Integration of Network Activity

    PubMed Central

    Croft, Wayne; Dobson, Katharine L.; Bellamy, Tomas C.

    2015-01-01

    The capacity of synaptic networks to express activity-dependent changes in strength and connectivity is essential for learning and memory processes. In recent years, glial cells (most notably astrocytes) have been recognized as active participants in the modulation of synaptic transmission and synaptic plasticity, implicating these electrically nonexcitable cells in information processing in the brain. While the concept of bidirectional communication between neurons and glia and the mechanisms by which gliotransmission can modulate neuronal function are well established, less attention has been focussed on the computational potential of neuron-glial transmission itself. In particular, whether neuron-glial transmission is itself subject to activity-dependent plasticity and what the computational properties of such plasticity might be has not been explored in detail. In this review, we summarize current examples of plasticity in neuron-glial transmission, in many brain regions and neurotransmitter pathways. We argue that induction of glial plasticity typically requires repetitive neuronal firing over long time periods (minutes-hours) rather than the short-lived, stereotyped trigger typical of canonical long-term potentiation. We speculate that this equips glia with a mechanism for monitoring average firing rates in the synaptic network, which is suited to the longer term roles proposed for astrocytes in neurophysiology. PMID:26339509

  10. Propagation of Epileptiform Activity Can Be Independent of Synaptic Transmission, Gap Junctions, or Diffusion and Is Consistent with Electrical Field Transmission

    PubMed Central

    Zhang, Mingming; Ladas, Thomas P.; Qiu, Chen; Shivacharan, Rajat S.; Gonzalez-Reyes, Luis E.

    2014-01-01

    The propagation of activity in neural tissue is generally associated with synaptic transmission, but epileptiform activity in the hippocampus can propagate with or without synaptic transmission at a speed of ∼0.1 m/s. This suggests an underlying common nonsynaptic mechanism for propagation. To study this mechanism, we developed a novel unfolded hippocampus preparation, from CD1 mice of either sex, which preserves the transverse and longitudinal connections and recorded activity with a penetrating microelectrode array. Experiments using synaptic transmission and gap junction blockers indicated that longitudinal propagation is independent of chemical or electrical synaptic transmission. Propagation speeds of 0.1 m/s are not compatible with ionic diffusion or pure axonal conduction. The only other means of communication between neurons is through electric fields. Computer simulations revealed that activity can indeed propagate from cell to cell solely through field effects. These results point to an unexpected propagation mechanism for neural activity in the hippocampus involving endogenous field effect transmission. PMID:24453330

  11. The Transmission Interfaces Contribute Asymmetrically to the Assembly and Activity of Human P-glycoprotein*

    PubMed Central

    Loo, Tip W.; Clarke, David M.

    2015-01-01

    P-glycoprotein (P-gp; ABCB1) is an ABC drug pump that protects us from toxic compounds. It is clinically important because it confers multidrug resistance. The homologous halves of P-gp each contain a transmembrane (TM) domain (TMD) with 6 TM segments followed by a nucleotide-binding domain (NBD). The drug- and ATP-binding sites reside at the interface between the TMDs and NBDs, respectively. Each NBD is connected to the TMDs by a transmission interface involving a pair of intracellular loops (ICLs) that form ball-and-socket joints. P-gp is different from CFTR (ABCC7) in that deleting NBD2 causes misprocessing of only P-gp. Therefore, NBD2 might be critical for stabilizing ICLs 2 and 3 that form a tetrahelix bundle at the NBD2 interface. Here we report that the NBD1 and NBD2 transmission interfaces in P-gp are asymmetric. Point mutations to 25 of 60 ICL2/ICL3 residues at the NBD2 transmission interface severely reduced P-gp assembly while changes to the equivalent residues in ICL1/ICL4 at the NBD1 interface had little effect. The hydrophobic nature at the transmission interfaces was also different. Mutation of Phe-1086 or Tyr-1087 to arginine at the NBD2 socket blocked activity or assembly while the equivalent mutations at the NBD1 socket had only modest effects. The results suggest that the NBD transmission interfaces are asymmetric. In contrast to the ICL2/3-NBD2 interface, the ICL1/4-NBD1 transmission interface is more hydrophilic and insensitive to mutations. Therefore the ICL2/3-NBD2 transmission interface forms a precise hydrophobic connection that acts as a linchpin for assembly and trafficking of P-gp. PMID:25987565

  12. LRE2, an active human L1 element, has low level transcriptional activity and extremely low reverse transcriptase activity

    SciTech Connect

    Holmes, S.E.; Dombroski, B.A.; Sassaman, D.M.

    1994-09-01

    Previously, we found a 2 kb insertion containing a rearranged L1 element plus a unique sequence component (USC) within exon 48 of the dystrophin gene of a patient with muscular dystrophy. We used the USC to clone the precursor of this insertion, the second known {open_quotes}active{close_quotes} human L1 element. The locus LRE2 (L1 Retrotransposable Element 2) has an allele derived from the patient which matches the insertion sequence exactly. LRE2 has a perfect 13-15 bp target site duplication, 2 open reading frames (ORFs), and an unusual 21 bp truncation of the 5{prime} end in a region known to be important for L1 transcription. The truncated LRE2 promoter has about 20% of the transcriptional activity of a previously studied L1 promoter after transfection into NTera2D1 cells of a construct in which the L1 promoter drives the expression of a lacZ gene. In addition, the reverse transcriptase (RT) encoded by LRE2 is active in an in vivo pseudogene assay in yeast and an in vitro assay. However, in both assays the RT of LRE2 is 1-5% as active as that of LRE1. These data demonstrate that multiple {open_quotes}active{close_quotes} L1 elements exist in the human genome, and that active elements can have highly variable rates of transcription and reverse transcriptase activity. That the RT of LRE2 has extremely low activity suggests the possibility that retrotransposition of an L1 element may in some cases involve an RT encoded by another L1 element.

  13. [KIL-d] Protein Element Confers Antiviral Activity via Catastrophic Viral Mutagenesis.

    PubMed

    Suzuki, Genjiro; Weissman, Jonathan S; Tanaka, Motomasa

    2015-11-19

    Eukaryotic cells are targeted by pathogenic viruses and have developed cell defense mechanisms against viral infection. In yeast, the cellular extrachromosomal genetic element [KIL-d] alters killer activity of M double-stranded RNA killer virus and confers cell resistance against the killer virus. However, its underlying mechanism and the molecular nature of [KIL-d] are unknown. Here, we demonstrate that [KIL-d] is a proteinaceous prion-like aggregate with non-Mendelian cytoplasmic transmission. Deep sequencing analyses revealed that [KIL-d] selectively increases the rate of de novo mutation in the killer toxin gene of the viral genome, producing yeast harboring a defective mutant killer virus with a selective growth advantage over those with WT killer virus. These results suggest that a prion-like [KIL-d] element reprograms the viral replication machinery to induce mutagenesis and genomic inactivation via the long-hypothesized mechanism of "error catastrophe." The findings also support a role for prion-like protein aggregates in cellular defense and adaptation. PMID:26590718

  14. Human immunodeficiency virus-induced pathology favored by cellular transmission and activation

    SciTech Connect

    Lewis, D.E.; Yoffe, B.; Bosworth, C.G.; Hollinger, F.B.; Rich, R.R.

    1988-03-01

    Epidemiological data suggest that transmission of human immunodeficiency virus (HIV) occurs primarily by transference of virally infected cells. However, the efficiency of lytic productive infection induced by HIV after transmission of cell-associated virus vs. free virus is difficult to assess. The present studies compare the extent of depletion of CD4+ (helper/inducer) T cells after mixing uninfected cells with either free HIV or irradiated HIV-infected allogeneic or autologous cells in vitro. Rapid CD4+ cellular depletion occurred only in cultures containing allogeneic infected cells or after addition of a nonspecific T cell activation signal to cultures with autologous infected cells. These in vitro observations strongly support the epidemiological implication that interactions between infected and uninfected cells are the most efficient means of transmission and HIV-induced cytopathology in vivo. They also provide direct support for the concept that immunological stimulation by foreign cells infected with HIV dramatically increases the likelihood of transmission. These in vitro observations suggest a model for the acquisition of HIV in vivo and the role of cellular activation in dissemination of the virus to uninfected cells in an infected individual.

  15. Germinal and Somatic Activity of the Maize Element Activator (Ac) in Arabidopsis

    PubMed Central

    Keller, J.; Lim, E.; James-Jr., D. W.; Dooner, H. K.

    1992-01-01

    We have investigated the germinal and somatic activity of the maize Activator (Ac) element in Arabidopsis with the objective of developing an efficient transposon-based system for gene isolation in that plant. Transposition activity was assayed with a chimeric marker that consists of the cauliflower mosaic virus 35S promoter and a bacterial streptomycin phosphotransferase gene (SPT). Somatic activity was detected in seedlings germinated on plates containing streptomycin as green-resistant sectors against a background of white-sensitive cells. Germinal excisions resulted in fully green seedlings. The transposition frequency was extremely low when a single copy of the transposon was present, but appeared to increase with an increase in Ac copy number. Plants that were selected as variegated produced an increased number of green progeny. The methylation state of the Ac elements in lines with either low or high levels of excision was assessed by restriction analysis. No difference was found between these lines, indicating that the degree of methylation did not contribute to the level of Ac activity. Germinal excision events were analyzed molecularly and shown to carry reinserted transposons in about 50% of the cases. In several instances, streptomycin-resistant siblings carried the same transposed Ac element, indicating that excision had occurred prior to meiosis in the parent. We discuss parameters that need to be considered to optimize the use of Ac as a transposon tag in Arabidopsis. PMID:1322854

  16. Solar Power Satellite Microwave Transmission and Reception

    NASA Technical Reports Server (NTRS)

    Dietz, R. H.

    1980-01-01

    Numerous analytical and experimental investigations related to SPS microwave power transmission and reception are reported. Aspects discussed include system performance, phase control, power amplifiers, radiating elements, rectenna, solid state configurations, and planned program activities.

  17. Experimental Study on Battery-Less Sensor Network Activated by Multi-Point Wireless Energy Transmission

    NASA Astrophysics Data System (ADS)

    Maehara, Daiki; Tran, Gia Khanh; Sakaguchi, Kei; Araki, Kiyomichi

    This paper empirically validates battery-less sensor activation via wireless energy transmission to release sensors from wires and batteries. To seamlessly extend the coverage and activate sensor nodes distributed in any indoor environment, we proposed multi-point wireless energy transmission with carrier shift diversity. In this scheme, multiple transmitters are employed to compensate path-loss attenuation and orthogonal frequencies are allocated to the multiple transmitters to avoid the destructive interference that occurs when the same frequency is used by all transmitters. In our previous works, the effectiveness of the proposed scheme was validated theoretically and also empirically by using just a spectrum analyzer to measure the received power. In this paper, we develop low-energy battery-less sensor nodes whose consumed power and required received power for activation are respectively 142 uW and 400 uW. In addition, we conduct indoor experiments in which the received power and activation of battery-less sensor node are simultaneously observed by using the developed battery-less sensor node and a spectrum analyzer. The results show that the coverage of single-point and multi-point wireless energy transmission without carrier shift diversity are, respectively, 84.4% and 83.7%, while the coverage of the proposed scheme is 100%. It can be concluded that the effectiveness of the proposed scheme can be verified by our experiments using real battery-less sensor nodes.

  18. Complementary chiral metasurface with strong broadband optical activity and enhanced transmission

    SciTech Connect

    Jia, Yan-Peng; Zhang, Yong-Liang; Dong, Xian-Zi E-mail: xmduan@mail.ipc.ac.cn; Zheng, Mei-Ling; Li, Jing; Liu, Jie; Zhao, Zhen-Sheng; Duan, Xuan-Ming E-mail: xmduan@mail.ipc.ac.cn

    2014-01-06

    We present the design and realization of ultra-thin chiral metasurfaces with giant broadband optical activity in the infrared wavelength. The chiral metasurfaces consisting of periodic hole arrays of complementary asymmetric split ring resonators are fabricated by femtosecond laser two-photon polymerization. Enhanced transmission with strong polarization conversion up to 97% is observed owing to the chiral surface plasmons resulting from mirror symmetry broken. The dependence of optical activity on the degree of structural asymmetry is investigated. This simple planar metasurface is expected to be useful for designing ultra-thin active devices and tailoring the polarization behavior of complex metallic nanostructures.

  19. Emergy of the Global Biogeochemical Cycles of Biologically Active Elements

    EPA Science Inventory

    Accurate estimates of the emergy of elemental flows are needed to accurately evaluate the far field effects of anthropogenic wastes. The transformity and specific emergy of the elements and of their different chemical species is also needed to quantify the inputs to many producti...

  20. The Juan non-LTR retrotransposon in mosquitoes: genomic impact, vertical transmission and indications of recent and widespread activity

    PubMed Central

    Biedler, James K; Tu, Zhijian

    2007-01-01

    evolutionary history. There are also indications that Juan has been recently active in a wide range of mosquito species. Furthermore, our research demonstrates that a Jockey clade non-LTR without target site-specificity has been sustained by vertical transmission in the mosquito family. These results strengthen the argument that non-LTRs tend to be genomic elements capable of persistence by vertical descent over a long evolutionary time. PMID:17620143

  1. The role of D2-autoreceptors in regulating dopamine neuron activity and transmission.

    PubMed

    Ford, C P

    2014-12-12

    Dopamine D2-autoreceptors play a key role in regulating the activity of dopamine neurons and control the synthesis, release and uptake of dopamine. These Gi/o-coupled inhibitory receptors play a major part in shaping dopamine transmission. Found at both somatodendritic and axonal sites, autoreceptors regulate the firing patterns of dopamine neurons and control the timing and amount of dopamine released from their terminals in target regions. Alterations in the expression and activity of autoreceptors are thought to contribute to Parkinson's disease as well as schizophrenia, drug addiction and attention-deficit hyperactivity disorder (ADHD), which emphasizes the importance of D2-autoreceptors in regulating the dopamine system. This review will summarize the cellular actions of dopamine autoreceptors and discuss recent advances that have furthered our understanding of the mechanisms by which D2-receptors control dopamine transmission. PMID:24463000

  2. Trace element analysis of coal by neutron activation

    NASA Technical Reports Server (NTRS)

    Sheibley, D. W.

    1973-01-01

    The irradiation, counting, and data reduction scheme is described for an analysis capability of 1000 samples per year. Up to 56 elements are reported on each sample. The precision and accuracy of the method are shown for 25 elements designated as hazardous by the Environmental Protection Agency (EPA). The interference corrections for selenium and ytterbium on mercury and ytterbium on selenium are described. The effect of bromine and antimony on the determination of arsenic is also mentioned. The use of factorial design techniques to evaluate interferences in the determination of mercury, selenium, and arsenic is shown. Some typical trace element results for coal, fly ash, and bottom ash are given.

  3. Trace element analysis of coal by neutron activation.

    NASA Technical Reports Server (NTRS)

    Sheibley, D. W.

    1973-01-01

    The irradiation, counting, and data reduction scheme is described for an analysis capability of 1000 samples per year. Up to 56 elements are reported on each sample. The precision and accuracy of the method are shown for 25 elements designated as hazardous by the Environmental Protection Agency (EPA). The interference corrections for selenium and ytterbium on mercury and ytterbium on selenium are described. The effect of bromine and antimony on the determination of arsenic is also mentioned. The use of factorial design techniques to evaluate interferences in the determination of mercury, selenium, and arsenic is shown. Some typical trace element results for coal, fly ash, and bottom ash are given.

  4. Rolling-element fatigue life with traction fluids and automatic transmission fluid in a high-speed rolling-contact rig

    NASA Technical Reports Server (NTRS)

    Parker, R. J.; Nahm, A. H.; Loewenthal, S. H.

    1982-01-01

    Rolling-element fatigue tests were run in standard and high-speed rolling-contact rigs at bar speeds from 5000 to 50,000 rpm to determine the effects of speed and lubricant film parameter on rolling-element fatigue life. AISI 52100 test bars were tested at a maximum Hertz stress of 4.83 GPa (700,000 psi) with three traction fluids and an automatic transmission fluid. Rolling-element fatigue life increased with speed, with the greatest increases occurring from 10,000 to 50,000 rpm. The life data tended to follow published life-versus-lubricant-film-parameter data up to a film parameter of approximately 3.

  5. Nuclear Thermal Rocket Element Environmental Simulator (NTREES) Upgrade Activities

    NASA Technical Reports Server (NTRS)

    Emrich, William J. Jr.; Moran, Robert P.; Pearson, J. Boise

    2012-01-01

    To support the on-going nuclear thermal propulsion effort, a state-of-the-art non nuclear experimental test setup has been constructed to evaluate the performance characteristics of candidate fuel element materials and geometries in representative environments. The facility to perform this testing is referred to as the Nuclear Thermal Rocket Element Environment Simulator (NTREES). This device can simulate the environmental conditions (minus the radiation) to which nuclear rocket fuel components will be subjected during reactor operation. Test articles mounted in the simulator are inductively heated in such a manner so as to accurately reproduce the temperatures and heat fluxes which would normally occur as a result of nuclear fission and would be exposed to flowing hydrogen. Initial testing of a somewhat prototypical fuel element has been successfully performed in NTREES and the facility has now been shutdown to allow for an extensive reconfiguration of the facility which will result in a significant upgrade in its capabilities

  6. Trace elements by instrumental neutron activation analysis for pollution monitoring

    NASA Technical Reports Server (NTRS)

    Sheibley, D. W.

    1975-01-01

    Methods and technology were developed to analyze 1000 samples/yr of coal and other pollution-related samples. The complete trace element analysis of 20-24 samples/wk averaged 3-3.5 man-hours/sample. The computerized data reduction scheme could identify and report data on as many as 56 elements. In addition to coal, samples of fly ash, bottom ash, crude oil, fuel oil, residual oil, gasoline, jet fuel, kerosene, filtered air particulates, ore, stack scrubber water, clam tissue, crab shells, river sediment and water, and corn were analyzed. Precision of the method was plus or minus 25% based on all elements reported in coal and other sample matrices. Overall accuracy was estimated at 50%.

  7. Salinomycin and Other Ionophores as a New Class of Antimalarial Drugs with Transmission-Blocking Activity

    PubMed Central

    D'Alessandro, Sarah; Corbett, Yolanda; Ilboudo, Denise P.; Misiano, Paola; Dahiya, Nisha; Abay, Solomon M.; Habluetzel, Annette; Grande, Romualdo; Gismondo, Maria R.; Dechering, Koen J.; Koolen, Karin M. J.; Sauerwein, Robert W.; Taramelli, Donatella; Parapini, Silvia

    2015-01-01

    The drug target profile proposed by the Medicines for Malaria Venture for a malaria elimination/eradication policy focuses on molecules active on both asexual and sexual stages of Plasmodium, thus with both curative and transmission-blocking activities. The aim of the present work was to investigate whether the class of monovalent ionophores, which includes drugs used in veterinary medicine and that were recently proposed as human anticancer agents, meets these requirements. The activity of salinomycin, monensin, and nigericin on Plasmodium falciparum asexual and sexual erythrocytic stages and on the development of the Plasmodium berghei and P. falciparum mosquito stages is reported here. Gametocytogenesis of the P. falciparum strain 3D7 was induced in vitro, and gametocytes at stage II and III or stage IV and V of development were treated for different lengths of time with the ionophores and their viability measured with the parasite lactate dehydrogenase (pLDH) assay. The monovalent ionophores efficiently killed both asexual parasites and gametocytes with a nanomolar 50% inhibitory concentration (IC50). Salinomycin showed a fast speed of kill compared to that of standard drugs, and the potency was higher on stage IV and V than on stage II and III gametocytes. The ionophores inhibited ookinete development and subsequent oocyst formation in the mosquito midgut, confirming their transmission-blocking activity. Potential toxicity due to hemolysis was excluded, since only infected and not normal erythrocytes were damaged by ionophores. Our data strongly support the downstream exploration of monovalent ionophores for repositioning as new antimalarial and transmission-blocking leads. PMID:26055362

  8. Finite Element Learning Modules as Active Learning Tools

    ERIC Educational Resources Information Center

    Brown, Ashland O.; Jensen, Daniel; Rencis, Joseph; Wood, Kristin; Wood, John; White, Christina; Raaberg, Kristen Kaufman; Coffman, Josh

    2012-01-01

    The purpose of active learning is to solicit participation by students beyond the passive mode of traditional classroom lectures. Reading, writing, participating in discussions, hands-on activities, engaging in active problem solving, and collaborative learning can all be involved. The skills acquired during active learning tend to go above and…

  9. Trace elements removal from water using modified activated carbon.

    PubMed

    Campos, V; Buchler, P M

    2008-02-01

    This paper present the possible alternative options for the remove of trace elements from drinking water supplies in the trace. Arsenic and chromium are two of the most toxic pollutants, introduced into natural waters from a variety of sources and causing various adverse effects on living bodies. The performance of three filter bed methods was evaluated in the laboratory. Experiments were conducted to investigate the sorption of arsenic and chromium on carbon steel and removal of trace elements from drinking water with a household filtration process. The affinity of the arsenic and chromium species for Fe/Fe3C (iron/iron carbide) sites is the key factor controlling the removal of the elements. The method is based on the use of powdered block carbon, powder carbon steel and ceramic spheres in the ion-sorption columns as a cleaning process. The modified powdered block carbon is a satisfactory and economical sorbent for trace elements (arsenite and chromate) dissolved in water due to its low unit cost of about $23 and compatibility with the traditional household filtration system. PMID:18613611

  10. ELEMENTAL MERCURY ADSORPTION BY ACTIVATED CARBON TREATED WITH SULFURIC ACID

    EPA Science Inventory

    The paper gives results of a study of the adsorption of elemental mercury at 125 C by a sulfuric-acid (H2S04, 50% w/w/ solution)-treated carbon for the removal of mercury from flue gas. The pore structure of the sample was characterized by nitrogen (N2) at -196 C and the t-plot m...

  11. Tracking and visualization of space-time activities for a micro-scale flu transmission study

    PubMed Central

    2013-01-01

    Background Infectious diseases pose increasing threats to public health with increasing population density and more and more sophisticated social networks. While efforts continue in studying the large scale dissemination of contagious diseases, individual-based activity and behaviour study benefits not only disease transmission modelling but also the control, containment, and prevention decision making at the local scale. The potential for using tracking technologies to capture detailed space-time trajectories and model individual behaviour is increasing rapidly, as technological advances enable the manufacture of small, lightweight, highly sensitive, and affordable receivers and the routine use of location-aware devices has become widespread (e.g., smart cellular phones). The use of low-cost tracking devices in medical research has also been proved effective by more and more studies. This study describes the use of tracking devices to collect data of space-time trajectories and the spatiotemporal processing of such data to facilitate micro-scale flu transmission study. We also reports preliminary findings on activity patterns related to chances of influenza infection in a pilot study. Methods Specifically, this study employed A-GPS tracking devices to collect data on a university campus. Spatiotemporal processing was conducted for data cleaning and segmentation. Processed data was validated with traditional activity diaries. The A-GPS data set was then used for visual explorations including density surface visualization and connection analysis to examine space-time activity patterns in relation to chances of influenza infection. Results When compared to diary data, the segmented tracking data demonstrated to be an effective alternative and showed greater accuracies in time as well as the details of routes taken by participants. A comparison of space-time activity patterns between participants who caught seasonal influenza and those who did not revealed interesting

  12. Nuclear Thermal Rocket Element Environmental Simulator (NTREES) Upgrade Activities

    NASA Technical Reports Server (NTRS)

    Emrich, William

    2013-01-01

    A key technology element in Nuclear Thermal Propulsion is the development of fuel materials and components which can withstand extremely high temperatures while being exposed to flowing hydrogen. NTREES provides a cost effective method for rapidly screening of candidate fuel components with regard to their viability for use in NTR systems. The NTREES is designed to mimic the conditions (minus the radiation) to which nuclear rocket fuel elements and other components would be subjected to during reactor operation. The NTREES consists of a water cooled ASME code stamped pressure vessel and its associated control hardware and instrumentation coupled with inductive heaters to simulate the heat provided by the fission process. The NTREES has been designed to safely allow hydrogen gas to be injected into internal flow passages of an inductively heated test article mounted in the chamber.

  13. Active Compounds Against Anopheles minimus Carboxypeptidase B for Malaria Transmission-Blocking Strategy.

    PubMed

    Mongkol, Watcharakorn; Arunyawat, Uraiwan; Surat, Wunrada; Kubera, Anchanee

    2015-11-01

    Malaria transmission-blocking compounds have been studied to block the transmission of malaria parasites, especially the drug-resistant Plasmodium. Carboxypeptidase B (CPB) in the midgut of Anopheline mosquitoes has been demonstrated to be essential for the sexual development of Plasmodium in the mosquito. Thus, the CPB is a potential target for blocking compounds. The aim of this research was to screen compounds from the National Cancer Institute (NCI) diversity dataset and U.S. Food and Drug Administration (FDA)-approved drugs that could reduce the Anopheles CPB activity. The cDNA fragment of cpb gene from An. minimus (cpbAmi) was amplified and sequenced. The three-dimensional structure of CPB was predicted from the deduced amino acid sequence. The virtual screening of the compounds from NCI diversity set IV and FDA-approved drugs was performed against CPBAmi. The inhibition activity against CPBAmi of the top-scoring molecules was characterized in vitro. Three compounds-NSC-1014, NSC-332670, and aminopterin with IC50 at 0.99 mM, 1.55 mM, and 0.062 mM, respectively-were found to significantly reduce the CPBAmi activity. PMID:26352934

  14. Physical mechanisms of active control of sound transmission through rib stiffened double-panel structure

    NASA Astrophysics Data System (ADS)

    Ma, Xiyue; Chen, Kean; Ding, Shaohu; Yu, Haoxin

    2016-06-01

    This paper presents an analytical investigation on physical mechanisms of actively controlling sound transmission through a rib stiffened double-panel structure using point source in the cavity. The combined modal expansion and vibro-acoustic coupling methods are applied to establish the theoretical model of such active structure. Under the condition of minimizing radiated power of the radiating ribbed plate, the physical mechanisms are interpreted in detail from the point of view of modal couplings similar as that used in existed literatures. Results obtained demonstrate that the rule of sound energy transmission and the physical mechanisms for the rib stiffened double-panel structure are all changed, and affected by the coupling effects of the rib when compared with the analytical results obtained for unribbed double-panel case. By taking the coupling effects of the rib into considerations, the cavity modal suppression and rearrangement mechanisms obtained in existed investigations are modified and supplemented for the ribbed plate case, which gives a clear interpretation for the physical nature involved in the active rib stiffened double-panel structure.

  15. Turning off the tap: stopping tuberculosis transmission through active case-finding and prompt effective treatment.

    PubMed

    Yuen, Courtney M; Amanullah, Farhana; Dharmadhikari, Ashwin; Nardell, Edward A; Seddon, James A; Vasilyeva, Irina; Zhao, Yanlin; Keshavjee, Salmaan; Becerra, Mercedes C

    2015-12-01

    To halt the global tuberculosis epidemic, transmission must be stopped to prevent new infections and new cases. Identification of individuals with tuberculosis and prompt initiation of effective treatment to rapidly render them non-infectious is crucial to this task. However, in settings of high tuberculosis burden, active case-finding is often not implemented, resulting in long delays in diagnosis and treatment. A range of strategies to find cases and ensure prompt and correct treatment have been shown to be effective in high tuberculosis-burden settings. The population-level effect of targeted active case-finding on reducing tuberculosis incidence has been shown by studies and projected by mathematical modelling. The inclusion of targeted active case-finding in a comprehensive epidemic-control strategy for tuberculosis should contribute substantially to a decrease in tuberculosis incidence. PMID:26515675

  16. MPTP-meditated hippocampal dopamine deprivation modulates synaptic transmission and activity-dependent synaptic plasticity

    SciTech Connect

    Zhu Guoqi; Chen Ying; Huang Yuying; Li Qinglin; Behnisch, Thomas

    2011-08-01

    Parkinson's disease (PD)-like symptoms including learning deficits are inducible by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Therefore, it is possible that MPTP may disturb hippocampal memory processing by modulation of dopamine (DA)- and activity-dependent synaptic plasticity. We demonstrate here that intraperitoneal (i.p.) MPTP injection reduces the number of tyrosine hydroxylase (TH)-positive neurons in the substantia nigra (SN) within 7 days. Subsequently, the TH expression level in SN and hippocampus and the amount of DA and its metabolite DOPAC in striatum and hippocampus decrease. DA depletion does not alter basal synaptic transmission and changes pair-pulse facilitation (PPF) of field excitatory postsynaptic potentials (fEPSPs) only at the 30 ms inter-pulse interval. In addition, the induction of long-term potentiation (LTP) is impaired whereas the duration of long-term depression (LTD) becomes prolonged. Since both LTP and LTD depend critically on activation of NMDA and DA receptors, we also tested the effect of DA depletion on NMDA receptor-mediated synaptic transmission. Seven days after MPTP injection, the NMDA receptor-mediated fEPSPs are decreased by about 23%. Blocking the NMDA receptor-mediated fEPSP does not mimic the MPTP-LTP. Only co-application of D1/D5 and NMDA receptor antagonists during tetanization resembled the time course of fEPSP potentiation as observed 7 days after i.p. MPTP injection. Together, our data demonstrate that MPTP-induced degeneration of DA neurons and the subsequent hippocampal DA depletion alter NMDA receptor-mediated synaptic transmission and activity-dependent synaptic plasticity. - Highlights: > I.p. MPTP-injection mediates death of dopaminergic neurons. > I.p. MPTP-injection depletes DA and DOPAC in striatum and hippocampus. > I.p. MPTP-injection does not alter basal synaptic transmission. > Reduction of LTP and enhancement of LTD after i.p. MPTP-injection. > Attenuation of NMDA-receptors mediated f

  17. Gametocytocidal Screen Identifies Novel Chemical Classes with Plasmodium falciparum Transmission Blocking Activity

    PubMed Central

    Sanders, Natalie G.; Sullivan, David J.; Mlambo, Godfree; Dimopoulos, George; Tripathi, Abhai K.

    2014-01-01

    Discovery of transmission blocking compounds is an important intervention strategy necessary to eliminate and eradicate malaria. To date only a small number of drugs that inhibit gametocyte development and thereby transmission from the mosquito to the human host exist. This limitation is largely due to a lack of screening assays easily adaptable to high throughput because of multiple incubation steps or the requirement for high gametocytemia. Here we report the discovery of new compounds with gametocytocidal activity using a simple and robust SYBR Green I- based DNA assay. Our assay utilizes the exflagellation step in male gametocytes and a background suppressor, which masks the staining of dead cells to achieve healthy signal to noise ratio by increasing signal of viable parasites and subtracting signal from dead parasites. By determining the contribution of exflagellation to fluorescent signal and using appropriate cutoff values, we were able to screen for gametocytocidal compounds. After assay validation and optimization, we screened an FDA approved drug library of approximately 1500 compounds, as well as the 400 compound MMV malaria box and identified 44 gametocytocidal compounds with sub to low micromolar IC50s. Major classes of compounds with gametocytocidal activity included quaternary ammonium compounds with structural similarity to choline, acridine-like compounds similar to quinacrine and pyronaridine, as well as antidepressant, antineoplastic, and anthelminthic compounds. Top drug candidates showed near complete transmission blocking in membrane feeding assays. This assay is simple, reproducible and demonstrated robust Z-factor values at low gametocytemia levels, making it amenable to HTS for identification of novel and potent gametocytocidal compounds. PMID:25157792

  18. Determination of elements in National Bureau of Standards' geological Standard Reference Materials by neutron activation analysis

    SciTech Connect

    Graham, C.C.; Glascock, M.D.; Carni, J.J.; Vogt, J.R.; Spalding, T.G.

    1982-08-01

    Instrumental neutron activation analysis (INAA) and prompt gamma neutron activation analysis (PGNAA) have been used to determine elemental concentrations in two recently issued National Bureau of Standards (NBS) Standard Reference Materials (SRM's). The results obtained are in good agreement with the certified and information values reported by NBS for those elements in each material for which comparisons are available. Average concentrations of 35 elements in SRM 278 obsidian rock and 32 elements in SRM 688 basalt rock are reported for comparison with results that may be obtained by other laboratories.

  19. Antimalarial Iron Chelator FBS0701 Blocks Transmission by Plasmodium falciparum Gametocyte Activation Inhibition

    PubMed Central

    Ferrer, Patricia; Vega-Rodriguez, Joel; Tripathi, Abhai K.; Jacobs-Lorena, Marcelo

    2014-01-01

    Reducing the transmission of the malarial parasite by Anopheles mosquitoes using drugs or vaccines remains a main focus in the efforts to control malaria. Iron chelators have been studied as potential antimalarial drugs due to their activities against different stages of the parasite. The iron chelator FBS0701 affects the development of Plasmodium falciparum early gametocytes and lowers blood-stage parasitemia. Here, we tested the effect of FBS0701 on stage V gametocyte infectivity for mosquitoes. The incubation of stage V gametocytes for up to 3 days with increasing concentrations of FBS0701 resulted in a significant dose-related reduction in mosquito infectivity, as measured by the numbers of oocysts per mosquito. The reduction in mosquito infectivity was due to the inhibition of male and female gametocyte activation. The preincubation of FBS0701 with ferric chloride restored gametocyte infectivity, showing that the inhibitory effect of FBS0701 was quenched by iron. Deferoxamine, another iron chelator, also reduced gametocyte infectivity but to a lesser extent. Finally, the simultaneous administration of drug and gametocytes to mosquitoes without previous incubation did not significantly reduce the numbers of oocysts. These results show the importance of gametocyte iron metabolism as a potential target for new transmission-blocking strategies. PMID:25512427

  20. Optical activity of catalytic elements of hetero-metallic nanostructures

    NASA Astrophysics Data System (ADS)

    Antosiewicz, Tomasz J.; Apell, S. Peter; Wadell, Carl; Langhammer, Christoph

    2015-05-01

    Interaction of light with metals in the form of surface plasmons is used in a wide range of applications in which the scattering decay channel is important. The absorption channel is usually thought of as unwanted and detrimental to the efficiency of the device. This is true in many applications, however, recent studies have shown that maximization of the decay channel of surface plasmons has potentially significant uses. One of these is the creation of electron-hole pairs or hot electrons which can be used for e.g. catalysis. Here, we study the optical properties of hetero-metallic nanostructures that enhance light interaction with the catalytic elements of the nanostructures. A hybridized LSPR that matches the spectral characteristic of the light source is excited. This LSPR through coupling between the plasmonic elements maximizes light absorption in the catalytic part of the nanostructure. Numerically calculated visible light absorption in the catalytic nanoparticles is enhanced 12-fold for large catalytic disks and by more 30 for small nanoparticles on the order of 5 nm. In experiments we measure a sizable increase in the absorption cross section when small palladium nanoparticles are coupled to a large silver resonator. These observations suggest that heterometallic nanostructures can enhance catalytic reaction rates.

  1. Influence of the airflow speed along transmission lines on the DC corona discharge loss, using finite element approach

    SciTech Connect

    Shemshadi, A.; Akbari, A.; Niayesh, K.

    2012-07-15

    Corona discharge is of great interest from the physical point of view and due to its numerous practical applications in industry and especially one of the most important sources of loss in the high voltage transmission lines. This paper provides guidelines for the amount of electric loss caused by corona phenomenon occurred around a DC high voltage wire placed between two flat plates and influence of wind speed rate on the amount of corona loss using COMSOL Multiphysics. So electric potential distribution patterns and charge density diffusion around the wire are studied in this article.

  2. Faraday-active Fabry-Perot resonator: transmission, reflection, and emissivity.

    PubMed

    Liptuga, Anatoliy; Morozhenko, Vasyl; Pipa, Viktor; Venger, Evgen; Kostiuk, Theodor

    2012-05-01

    The propagation of light within a semiconductor Faraday-active Fabry-Perot resonator is investigated theoretically and experimentally. It is shown that an external magnetic field radically changes the angular and spectral characteristics of transmission, reflection, and emissivity of the resonator not only for polarized, but also for unpolarized, light. Suppression of interference patterns and phase inversion of the interference extrema were observed in both monochromatic and polychromatic light. The investigations were carried out for the plane-parallel plates of n-InAs in the spectral range of free charge carrier absorption. The results can be used to create new controllable optical and spectroscopic devices for investigation of Faraday-active material properties and for control of parameters of plane-parallel layers and structures. PMID:22561938

  3. Faraday-Active Fabry-Perot Resonator: Transmission, Reflection, and Emissivity

    NASA Technical Reports Server (NTRS)

    Liptuga, Anatoliy; Morozhenko, Vasyl; Pipa, Viktor; Venger, Evgen; Kostiuk, Theodor

    2011-01-01

    The propagation of light within a semiconductor Faraday-active Fabry-Perot resonator (FAFR) is investigated theoretically and experimentally. It is shown that an external magnetic field radically changes the angular and spectral characteristics of transmission, reflection and emissivity of the resonator not only for polarized, but also for unpolarized light. Suppression of interference patterns and phase inversion of the interference extrema were observed in both monochromatic and polychromatic light. The investigations were carried out for the plane-parallel plates of n-InAs in the spectral range of free charge carrier absorption. The results can be used to create new controllable optical and spectroscopic devices for investigation of Faraday-active material properties and for control of parameters of plane-parallel layers and structures.

  4. Post-injection transmission scans in a PET camera operating without septa with simultaneous measurement of emission activity contamination

    SciTech Connect

    Smith, R.J.; Karp, J.S.

    1996-08-01

    The authors report here on methods developed to reliably perform attenuation correction by post-injection transmission in a volume imaging PET scanner. The method directly measures the emission contamination during the transmission study, using a virtual transmission source position offset by 20{degree} from the actual {sup 68}Ge transmission source. Events are recorded only if they meet a co-linearity requirement with either the real or virtual source position. The simultaneous measurements of the emission contamination and transmission data remove the need for complex corrections to the emission data and are not subject to activity redistributions between emission and transmission scans performed sequentially. Correction is necessary, however, for the extra deadtime that varies with the amount of emission activity in the FOV. The extra deadtime is determined from a lookup table of deadtime as a function of detector countrates, which are recorded during the study. The lookup table is based upon phantom measurements. Using patient and phantom data, with both pre- and post-injection transmission measurements, this method is shown to be reliable for attenuation correction in the body. In addition, it enables the calculation of Standardized Uptake Values for analyzing tumor activity.

  5. Preconcentration and Speciation of Trace Elements and Trace-Element Analogues of Radionuclides by Neutron Activation Analysis

    SciTech Connect

    Chatt, A.

    1999-11-14

    We have developed a number of preconcentration neutron activation analysis (PNAA) methods in our laboratory for the determination of trace elements in a variety of complex sample matrices. We developed a number of cocrystallization and coprecipitation methods for the determination of trace elements in water samples. We developed several methods for the determination of I in foods and diets. We have developed a number of PNAA methods in our laboratory We determined As and Sb in geological materials and natural waters by coprecipitation with Se and Au in silicate rocks and ores by coprecipitation with Te followed by NAA. We developed an indirect NAA method for the determination of B in leachates of borosilicate glass. We have been interested in studying the speciation of Am, Tc, and Np in simulated vitrified groundwater leachates of high-level wastes under oxid and anoxic conditions using a number of techniques. We then used PNAA methods to study speciation of trace-element analogues of radionuclides. We have been able to apply biochemical techniques and NAA for the separation, preconcentration, and characterization of metalloprotein and protein-bound trace-element species in subcellular fractions of bovine kidneys. Lately, we have concentrated our efforts to develop chemical and biochemical methods in conjunction with NAA, NMR, and MS for the separation and identification of extractable organohalogens (EOX) in tissues of beluga whales, cod, and northern pink shrimp

  6. The impact of a parkinsonian lesion on dynamic striatal dopamine transmission depends on nicotinic receptor activation.

    PubMed

    Jennings, Katie A; Platt, Nicola J; Cragg, Stephanie J

    2015-10-01

    Dopamine function is disturbed in Parkinson's disease (PD), but whether and how release of dopamine from surviving neurons is altered has long been debated. Nicotinic acetylcholine receptors (nAChRs) on dopamine axons powerfully govern dopamine release and could be critical contributing factors. We revisited whether fundamental properties of dopamine transmission are changed in a parkinsonian brain and tested the potentially profound masking effects of nAChRs. Using real-time detection of dopamine in mouse striatum after a partial 6-hydroxydopamine lesion and under nAChR inhibition, we reveal that dopamine signals show diminished sensitivity to presynaptic activity. This effect manifested as diminished contrast between DA release evoked by the lowest versus highest frequencies. This reduced activity-dependence was underpinned by loss of short-term facilitation of dopamine release, consistent with an increase in release probability (Pr). With nAChRs active, the reduced activity-dependence of dopamine release after a parkinsonian lesion was masked. Consequently, moment-by-moment variation in activity of nAChRs may lead to dynamic co-variation in dopamine signal impairments in PD. PMID:26117304

  7. The impact of a parkinsonian lesion on dynamic striatal dopamine transmission depends on nicotinic receptor activation

    PubMed Central

    Jennings, Katie A.; Platt, Nicola J.; Cragg, Stephanie J.

    2015-01-01

    Dopamine function is disturbed in Parkinson's disease (PD), but whether and how release of dopamine from surviving neurons is altered has long been debated. Nicotinic acetylcholine receptors (nAChRs) on dopamine axons powerfully govern dopamine release and could be critical contributing factors. We revisited whether fundamental properties of dopamine transmission are changed in a parkinsonian brain and tested the potentially profound masking effects of nAChRs. Using real-time detection of dopamine in mouse striatum after a partial 6-hydroxydopamine lesion and under nAChR inhibition, we reveal that dopamine signals show diminished sensitivity to presynaptic activity. This effect manifested as diminished contrast between DA release evoked by the lowest versus highest frequencies. This reduced activity-dependence was underpinned by loss of short-term facilitation of dopamine release, consistent with an increase in release probability (Pr). With nAChRs active, the reduced activity-dependence of dopamine release after a parkinsonian lesion was masked. Consequently, moment-by-moment variation in activity of nAChRs may lead to dynamic co-variation in dopamine signal impairments in PD. PMID:26117304

  8. Emergy Evaluations of the Global Biogeochemical Cycles of Six Biologically Active Elements and Two Compounds

    EPA Science Inventory

    Estimates of the emergy carried by the flows of biologically active elements (BAE) and compounds are needed to accurately evaluate the near and far field effects of anthropogenic wastes. The transformities and specific emergies of these elements and of their different chemical sp...

  9. Disruption of hippocampal–prefrontal cortex activity by dopamine D2R-dependent LTD of NMDAR transmission

    PubMed Central

    Banks, Paul James; Burroughs, Amelia Caroline; Barker, Gareth Robert Isaac; Brown, Jon Thomas; Warburton, Elizabeth Clea; Bashir, Zafar Iqbal

    2015-01-01

    Functional connectivity between the hippocampus and prefrontal cortex (PFC) is essential for associative recognition memory and working memory. Disruption of hippocampal–PFC synchrony occurs in schizophrenia, which is characterized by hypofunction of NMDA receptor (NMDAR)-mediated transmission. We demonstrate that activity of dopamine D2-like receptors (D2Rs) leads selectively to long-term depression (LTD) of hippocampal–PFC NMDAR-mediated synaptic transmission. We show that dopamine-dependent LTD of NMDAR-mediated transmission profoundly disrupts normal synaptic transmission between hippocampus and PFC. These results show how dopaminergic activation induces long-term hypofunction of NMDARs, which can contribute to disordered functional connectivity, a characteristic that is a hallmark of psychiatric disorders such as schizophrenia. PMID:26286993

  10. Disruption of hippocampal-prefrontal cortex activity by dopamine D2R-dependent LTD of NMDAR transmission.

    PubMed

    Banks, Paul James; Burroughs, Amelia Caroline; Barker, Gareth Robert Isaac; Brown, Jon Thomas; Warburton, Elizabeth Clea; Bashir, Zafar Iqbal

    2015-09-01

    Functional connectivity between the hippocampus and prefrontal cortex (PFC) is essential for associative recognition memory and working memory. Disruption of hippocampal-PFC synchrony occurs in schizophrenia, which is characterized by hypofunction of NMDA receptor (NMDAR)-mediated transmission. We demonstrate that activity of dopamine D2-like receptors (D2Rs) leads selectively to long-term depression (LTD) of hippocampal-PFC NMDAR-mediated synaptic transmission. We show that dopamine-dependent LTD of NMDAR-mediated transmission profoundly disrupts normal synaptic transmission between hippocampus and PFC. These results show how dopaminergic activation induces long-term hypofunction of NMDARs, which can contribute to disordered functional connectivity, a characteristic that is a hallmark of psychiatric disorders such as schizophrenia. PMID:26286993

  11. Transgenerational transmission of systemic mast cell activation disease-genetic and epigenetic features.

    PubMed

    Molderings, Gerhard J

    2016-08-01

    Systemic mast cell activation disease (MCAD) comprises disorders characterized by an enhanced release of mast cell mediators accompanied by a varying accumulation of dysfunctional mast cells. Within the last years, evidence has been presented that MCAD is a multifactorial polygenic determined disease with the KIT(D816V) mutation and its induced functional consequences considered as special case. The respective genes encode proteins for various signaling pathways, epigenetic regulators, the RNA splicing machinery, and transcription factors. Transgenerational transmission of MCAD appears to be quite common. The basics of the molecular mechanisms underlying predisposition of the disease, that is, somatic and germline mutations and the contribution of epigenetic processes have become identifiable. The aim of the present review is to present and discuss available genetic, epigenetic and epidemiological findings, and to present a model of MCAD pathogenesis. PMID:26880691

  12. Simultaneous reconstruction of emission activity and attenuation coefficient distribution from TOF data, acquired with external transmission source

    NASA Astrophysics Data System (ADS)

    Panin, V. Y.; Aykac, M.; Casey, M. E.

    2013-06-01

    The simultaneous PET data reconstruction of emission activity and attenuation coefficient distribution is presented, where the attenuation image is constrained by exploiting an external transmission source. Data are acquired in time-of-flight (TOF) mode, allowing in principle for separation of emission and transmission data. Nevertheless, here all data are reconstructed at once, eliminating the need to trace the position of the transmission source in sinogram space. Contamination of emission data by the transmission source and vice versa is naturally modeled. Attenuated emission activity data also provide additional information about object attenuation coefficient values. The algorithm alternates between attenuation and emission activity image updates. We also proposed a method of estimation of spatial scatter distribution from the transmission source by incorporating knowledge about the expected range of attenuation map values. The reconstruction of experimental data from the Siemens mCT scanner suggests that simultaneous reconstruction improves attenuation map image quality, as compared to when data are separated. In the presented example, the attenuation map image noise was reduced and non-uniformity artifacts that occurred due to scatter estimation were suppressed. On the other hand, the use of transmission data stabilizes attenuation coefficient distribution reconstruction from TOF emission data alone. The example of improving emission images by refining a CT-based patient attenuation map is presented, revealing potential benefits of simultaneous CT and PET data reconstruction.

  13. Simultaneous reconstruction of emission activity and attenuation coefficient distribution from TOF data, acquired with external transmission source.

    PubMed

    Panin, V Y; Aykac, M; Casey, M E

    2013-06-01

    The simultaneous PET data reconstruction of emission activity and attenuation coefficient distribution is presented, where the attenuation image is constrained by exploiting an external transmission source. Data are acquired in time-of-flight (TOF) mode, allowing in principle for separation of emission and transmission data. Nevertheless, here all data are reconstructed at once, eliminating the need to trace the position of the transmission source in sinogram space. Contamination of emission data by the transmission source and vice versa is naturally modeled. Attenuated emission activity data also provide additional information about object attenuation coefficient values. The algorithm alternates between attenuation and emission activity image updates. We also proposed a method of estimation of spatial scatter distribution from the transmission source by incorporating knowledge about the expected range of attenuation map values. The reconstruction of experimental data from the Siemens mCT scanner suggests that simultaneous reconstruction improves attenuation map image quality, as compared to when data are separated. In the presented example, the attenuation map image noise was reduced and non-uniformity artifacts that occurred due to scatter estimation were suppressed. On the other hand, the use of transmission data stabilizes attenuation coefficient distribution reconstruction from TOF emission data alone. The example of improving emission images by refining a CT-based patient attenuation map is presented, revealing potential benefits of simultaneous CT and PET data reconstruction. PMID:23648397

  14. Compensation for thermally induced birefringence in polycrystalline ceramic active elements

    SciTech Connect

    Kagan, M A; Khazanov, E A

    2003-10-31

    Polycrystalline ceramics differ significantly from single crystals in that the crystallographic axes (and hence of the axes of thermally induced birefringence) are oriented randomly in each granule of the ceramic. The quaternion formalism is employed to calculate the depolarisation in the ceramics and the efficiency of its compensation. The obtained analytic expressions are in good agreement with the numerical relations. It is shown that the larger the ratio of the sample length to the granule size, the closer the properties of the ceramics to those of a single crystal with the [111] orientation (in particular, the uncompensated depolarisation is inversely proportional to this ratio). (active media)

  15. Optimal placement of active elements in control augmented structural synthesis

    NASA Technical Reports Server (NTRS)

    Sepulveda, A. E.; Jin, I. M.; Schmit, L. A., Jr.

    1992-01-01

    A methodology for structural/control synthesis is presented in which the optimal location of active members is treated in terms of (0,1) variables. Structural member sizes, control gains and (0,1) placement variables are treated simultaneously as design variables. Optimization is carried out by generating and solving a sequence of explicit approximate problems using a branch and bound strategy. Intermediate design variable and intermediate response quantity concepts are used to enhance the quality of the approximate design problems. Numerical results for example problems are presented to illustrate the efficacy of the design procedure set forth.

  16. neutron activation analysis using thermochromatography. II. thermochromatographic separation of elements in the analysis of geological samples

    SciTech Connect

    Sattarov, G.; Davydov, A.V.; Khamatov, S.; Kist, A.A.

    1986-07-01

    The use of gas thermochromatography (GTC) in the radioactivation analysis of difficulty soluble samples with a strongly activating substrate is discussed. The effect of sample coarseness and ore type on the rate of extraction of gold and accompanying elements was studied. The limits of detection of 22 elements were compared using neutron activation analysis with GTC and INAA. The analytical parameters of the procedure were estimated.

  17. Chronic activation of CB2 cannabinoid receptors in the hippocampus increases excitatory synaptic transmission

    PubMed Central

    Kim, Jimok; Li, Yong

    2015-01-01

    The roles of CB1 cannabinoid receptors in regulating neuronal activity have been extensively characterized. Although early studies show that CB1 receptors are present in the nervous system and CB2 cannabinoid receptors are in the immune system, recent evidence indicates that CB2 receptors are also expressed in the brain. Activation or blockade of CB2 receptors in vivo induces neuropsychiatric effects, but the cellular mechanisms of CB2 receptor function are unclear. The aim of this study is to determine how activation of CB2 receptors present in the hippocampus regulates synaptic function. Here, we show that when organotypic cultures of rodent hippocampal slices were treated with a CB2 receptor agonist (JWH133 or GP1a) for 7–10 days, quantal glutamate release became more frequent and spine density was increased via extracellular signal-regulated kinases. Chronic intraperitoneal injection of JWH133 into mice also increased excitatory synaptic transmission. These effects were blocked by a CB2 receptor antagonist (SR144528) or absent from hippocampal slices of CB2 receptor knock-out mice. This study reveals a novel cellular function of CB2 cannabinoid receptors in the hippocampus and provides insights into how cannabinoid receptor subtypes diversify the roles of cannabinoids in the brain. PMID:25504573

  18. Which Neuronal Elements are Activated Directly by Spinal Cord Stimulation.

    PubMed

    Holsheimer, Jan

    2002-01-01

    The purpose of this paper is to discuss which nerve fibers in the various quadrants of the spinal cord are immediately activated under normal conditions of spinal cord stimulation, ie, at voltages within the therapeutic range. The conclusions are based on both empirical and computer modeling data. The recruitment of dorsal column (DC) fibers is most likely restricted to Aβ fibers with a diameter ≥ 10.7 μm in a 0.20-0.25 mm layer under the pia mater and fibers of 9.4-10.7 μm in an even smaller outer layer when a conventional SCS lead is used. In a 0.25-mm outer layer of the T11 segment the number of Aβ fibers ≥ 10.7 μm, as estimated in a recent morphometric study, is about 56 in each DC. Because a DC at T11 innervates 12 dermatomes, a maximum of 4-5 fibers (≥ 10.7 μm) may be recruited in each dermatome near the discomfort threshold. The dermatome activated just below the discomfort threshold is likely to be stimulated by just a single fiber, suggesting that paresthesia and pain relief may be effected in a dermatome by the stimulation of a single large Aβ fiber. The depth of stimulation in the DCs, and thereby the number of recruited Aβ fibers, may be increased 2-3 fold when stimulation is applied by an optimized electrode configuration (a narrow bi/tripole or a transverse tripole). Assuming that the largest Aβ fibers in a dorsal root have a diameter of 15 μm, the smallest ones recruited at discomfort threshold would be 12 μm. The latter are presumably of proprioceptive origin and responsible for segmental reflexes and uncomfortable sensations. Furthermore, it is shown to be unlikely that, apart from dorsal roots and a thin outer layer of the DCs, any other spinal structures are recruited when stimulation is applied in the dorsal epidural space. Finally, anodal excitation and anodal propagation block are unlikely to occur with SCS. PMID:22151778

  19. Integration and transmission of distributed deterministic neural activity in feed-forward networks.

    PubMed

    Asai, Yoshiyuki; Villa, Alessandro E P

    2012-01-24

    A ten layer feed-forward network characterized by diverging/converging patterns of projection between successive layers of regular spiking (RS) neurons is activated by an external spatiotemporal input pattern fed to Layer 1 in presence of stochastic background activities fed to all layers. We used three dynamical systems to derive the external input spike trains including the temporal information, and three types of neuron models for the network, i.e. either a network formed either by neurons modeled by exponential integrate-and-fire dynamics (RS-EIF, Fourcaud-Trocmé et al., 2003), or by simple spiking neurons (RS-IZH, Izhikevich, 2004) or by multiple-timescale adaptive threshold neurons (RS-MAT, Kobayashi et al., 2009), given five intensities for the background activity. The assessment of the temporal structure embedded in the output spike trains was carried out by detecting the preferred firing sequences for the reconstruction of de-noised spike trains (Asai and Villa, 2008). We confirmed that the RS-MAT model is likely to be more efficient in integrating and transmitting the temporal structure embedded in the external input. We observed that this structure could be propagated not only up to the 10th layer but in some cases it was retained better beyond the 4th downstream layers. This study suggests that diverging/converging network structures, by the propagation of synfire activity, could play a key role in the transmission of complex temporal patterns of discharges associated to deterministic nonlinear activity. This article is part of a Special Issue entitled Neural Coding. PMID:22071564

  20. Activation of enhancer elements by the homeobox gene Cdx2 is cell line specific.

    PubMed Central

    Taylor, J K; Levy, T; Suh, E R; Traber, P G

    1997-01-01

    Cdx2 is a caudal-related homeodomain transcription factor that is expressed in complex patterns during mouse development and at high levels in the intestinal epithelium of adult mice. Cdx2 activates transcription of intestinal gene promoters containing specific binding sites. Moreover, Cdx2 has been shown to induce intestinal differentiation in cell lines. In this study, we show that Cdx2 is able to bind to two well defined enhancer elements in the HoxC8 gene. We then demonstrate that Cdx2 is able to activate transcription of heterologous promoters when its DNA binding element is placed in an enhancer context. Furthermore, the ability to activate enhancer elements is cell-line dependent. When the Cdx2 activation domain was linked to the Gal4 DNA binding domain, the chimeric protein was able to activate Gal4 enhancer constructs in an intestinal cell line, but was unable to activate transcription in NIH3T3 cells. These data suggest that there are cell-specific factors that allow the Cdx2 activation domain to function in the activation of enhancer elements. We hypothesize that either a co-activator protein or differential phosphorylation of the activation domain may be the mechanism for intestinal cell line-specific function of Cdx2 and possibly in other tissues in early development. PMID:9171078

  1. Tunable diffractive optical elements on various electro active polymers

    NASA Astrophysics Data System (ADS)

    Döring, Sebastian; Kollosche, Matthias; Hildebrandt, Niko; Stumpe, Joachim; Kofod, Guggi

    2010-05-01

    An innovative approach for voltage-tunable optical gratings based on dielectric elastomer actuators (DEAs) using electro active polymers is presented. Sinusoidal surface gratings, holographically written into azobenzene containing films, are transferred via nanoimprinting to DEAs of different carrier materials. We demonstrate that the surface relief deformation depends on the mechanical and geometrical properties of the actuators. The tested DEAs were made using commercially available elastomers, including a tri-block copolymer poly-styrene-ethylene-butadiene-styrene (SEBS), a silicone polydimethylsiloxane rubber (PDMS) and commonly used polyacrylic glue. The polyacrylic glue is ready to use, whereas the SEBS and the PDMS precursors have to be processed into thin films via different casting methods. The DEA material was pre-stretched, fixed to a stiff frame and coated with stretchable electrodes in appropriate designs. Since the actuation strain of the DEA depends strongly upon the conditions such as material properties, pre-stretch and geometry, the desired voltage-controllable deformations can be optimized during manufacturing of the DEA and also in the choice of materials in the grating transfer process. A full characterization of the grating deformation includes measurements of the grating pitch and depth modulation, plus the change of the diffraction angle and efficiency. The structural surface distortion was characterized by measuring the shape of the transmitted and diffracted laser beam with a beam profiling system while applying an electro-mechanical stress to the grating. Such surface distortions may lead to decreasing diffraction efficiency and lower beam quality. With properly chosen manufacturing parameters, we found a period shift of up to 9 % in a grating with 1 μm pitch. To describe the optical behavior, a model based on independently measured material parameters is presented.

  2. Activity of Herbal Medicines on Plasmodium falciparum Gametocytes: Implications for Malaria Transmission in Ghana

    PubMed Central

    Amoah, Linda Eva; Kakaney, Courage; Kwansa-Bentum, Bethel; Kusi, Kwadwo Asamoah

    2015-01-01

    Background Malaria still remains a major health issue in Ghana despite the introduction of Artemisinin-based combination therapy (ACT) coupled with other preventative measures such as the use of insecticide treated nets (ITNs). The global quest for eradication of malaria has heightened the interest of identifying drugs that target the sexual stage of the parasite, referred to as transmission-blocking drugs. This study aimed at assessing the efficacy and gametocydal effects of some commonly used herbal malaria products in Ghana. Methodology/Principal Findings After identifying herbal anti-malarial products frequently purchased on the Ghanaian market, ten of them were selected and lyophilized. In vitro drug sensitivity testing of different concentrations of the herbal products was carried out on asexual and in vitro generated gametocytes of the 3D7 strain of Plasmodium falciparum. The efficacies of the products were assessed by microscopy. Cultures containing low dose of RT also produced the least number of late stage gametocytes. Two of the herbal products CM and RT inhibited the growth of late stage gametocytes by > 80% at 100 μg/ml whilst KG was the most inhibitory to early stage gametocytes at that same concentration. However at 1 μg/ml, only YF significantly inhibited the survival of late stage gametocytes although at that same concentration YF barely inhibited the survival of early stage gametocytes. Conclusions/Significance Herbal product RT (Aloe schweinfurthii, Khaya senegalensis, Piliostigma thonningii and Cassia siamea) demonstrated properties of a highly efficacious gametocydal product. Low dose of herbal product RT exhibited the highest gametocydal activity and at 100 μg/ml, RT exhibited >80% inhibition of late stage gametocytes. However inhibition of asexual stage parasite by RT was not optimal. Improving the asexual inhibition of RT could convert RT into an ideal antimalarial herbal product. We also found that generally C. sanguinolenta containing

  3. Surveillance for Neisseria meningitidis Disease Activity and Transmission Using Information Technology

    PubMed Central

    Ahmed, S. Sohail; Oviedo-Orta, Ernesto; Mekaru, Sumiko R.; Freifeld, Clark C.; Tougas, Gervais; Brownstein, John S.

    2015-01-01

    Background While formal reporting, surveillance, and response structures remain essential to protecting public health, a new generation of freely accessible, online, and real-time informatics tools for disease tracking are expanding the ability to raise earlier public awareness of emerging disease threats. The rationale for this study is to test the hypothesis that the HealthMap informatics tools can complement epidemiological data captured by traditional surveillance monitoring systems for meningitis due to Neisseria meningitides (N. meningitides) by highlighting severe transmissible disease activity and outbreaks in the United States. Methods Annual analyses of N. meningitides disease alerts captured by HealthMap were compared to epidemiological data captured by the Centers for Disease Control’s Active Bacterial Core surveillance (ABCs) for N. meningitides. Morbidity and mortality case reports were measured annually from 2010 to 2013 (HealthMap) and 2005 to 2012 (ABCs). Findings HealthMap N. meningitides monitoring captured 80-90% of alerts as diagnosed N. meningitides, 5-20% of alerts as suspected cases, and 5-10% of alerts as related news articles. HealthMap disease alert activity for emerging disease threats related to N. meningitides were in agreement with patterns identified historically using traditional surveillance systems. HealthMap’s strength lies in its ability to provide a cumulative “snapshot” of weak signals that allows for rapid dissemination of knowledge and earlier public awareness of potential outbreak status while formal testing and confirmation for specific serotypes is ongoing by public health authorities. Conclusions The underreporting of disease cases in internet-based data streaming makes inadequate any comparison to epidemiological trends illustrated by the more comprehensive ABCs network published by the Centers for Disease Control. However, the expected delays in compiling confirmatory reports by traditional surveillance systems

  4. Bombesin facilitates GABAergic transmission and depresses epileptiform activity in the entorhinal cortex.

    PubMed

    Zhang, Hao-peng; Xiao, Zhaoyang; Cilz, Nicholas I; Hu, Binqi; Dong, Hailong; Lei, Saobo

    2014-01-01

    Bombesin and the bombesin-like peptides including neuromedin B (NMB) and gastrin-releasing peptide (GRP) are important neuromodulators in the brain. We studied their effects on GABAergic transmission and epileptiform activity in the entorhinal cortex (EC). Bath application of bombesin concentration-dependently increased both the frequency and amplitude of sIPSCs recorded from the principal neurons in the EC. Application of NMB and GRP exerted the same effects as bombesin. Bombesin had no effects on mIPSCs recorded in the presence of TTX but slightly depressed the evoked IPSCs. Omission of extracellular Ca(2+) or inclusion of voltage-gated Ca(2+) channel blockers, Cd(2+) and Ni(2+), blocked bombesin-induced increases in sIPSCs suggesting that bombesin increases GABA release via facilitating extracellular Ca(2+) influx. Bombesin induced membrane depolarization and slightly increased the input resistance of GABAergic interneurons recorded from layer III of the EC. The action potential firing frequency of the interneurons was also increased by bombesin. Bombesin-mediated depolarization of interneurons was unlikely to be mediated by the opening of a cationic conductance but due to the inhibition of inward rectifier K(+) channels. Bath application of bombesin, NMB and GRP depressed the frequency of the epileptiform activity elicited by deprivation of Mg(2+) from the extracellular solution suggesting that bombesin and the bombesin-like peptides have antiepileptic effects in the brain. PMID:23966303

  5. Novel Endoperoxide-Based Transmission-Blocking Antimalarials with Liver- and Blood-Schizontocidal Activities

    PubMed Central

    2013-01-01

    In a search for effective compounds against both the blood- and liver-stages of infection by malaria parasites with the ability to block the transmission of the disease to mosquito vectors, a series of hybrid compounds combining either a 1,2,4-trioxane or 1,2,4,5-tetraoxane and 8-aminoquinoline moieties were synthesized and screened for their antimalarial activity. These hybrid compounds showed high potency against both exoerythrocytic and erythrocytic forms of malaria parasites, comparable to representative trioxane-based counterparts. Furthermore, they efficiently blocked the development of the sporogonic cycle in the mosquito vector. The tetraoxane-based hybrid 5, containing an amide linker between the two moieties, effectively cleared a patent blood-stage P. berghei infection in mice after i.p. administration. Overall, these results indicate that peroxide-8-aminoquinoline hybrids are excellent starting points to develop an agent that conveys all the desired antimalarial multistage activities in a single chemical entity and, as such, with the potential to be used in malaria elimination campaigns. PMID:24900781

  6. Novel endoperoxide-based transmission-blocking antimalarials with liver- and blood-schizontocidal activities.

    PubMed

    Miranda, Daniela; Capela, Rita; Albuquerque, Inês S; Meireles, Patrícia; Paiva, Isa; Nogueira, Fátima; Amewu, Richard; Gut, Jiri; Rosenthal, Philip J; Oliveira, Rudi; Mota, Maria M; Moreira, Rui; Marti, Francesc; Prudêncio, Miguel; O'Neill, Paul M; Lopes, Francisca

    2014-02-13

    In a search for effective compounds against both the blood- and liver-stages of infection by malaria parasites with the ability to block the transmission of the disease to mosquito vectors, a series of hybrid compounds combining either a 1,2,4-trioxane or 1,2,4,5-tetraoxane and 8-aminoquinoline moieties were synthesized and screened for their antimalarial activity. These hybrid compounds showed high potency against both exoerythrocytic and erythrocytic forms of malaria parasites, comparable to representative trioxane-based counterparts. Furthermore, they efficiently blocked the development of the sporogonic cycle in the mosquito vector. The tetraoxane-based hybrid 5, containing an amide linker between the two moieties, effectively cleared a patent blood-stage P. berghei infection in mice after i.p. administration. Overall, these results indicate that peroxide-8-aminoquinoline hybrids are excellent starting points to develop an agent that conveys all the desired antimalarial multistage activities in a single chemical entity and, as such, with the potential to be used in malaria elimination campaigns. PMID:24900781

  7. Melatonin receptor activation increases glutamatergic synaptic transmission in the rat medial lateral habenula.

    PubMed

    Evely, Katherine M; Hudson, Randall L; Dubocovich, Margarita L; Haj-Dahmane, Samir

    2016-05-01

    Melatonin (MLT) is secreted from the pineal gland and mediates its physiological effects through activation of two G protein-coupled receptors, MT1 and MT2 . These receptors are expressed in several brain areas, including the habenular complex, a pair of nuclei that relay information from forebrain to midbrain and modulate a plethora of behaviors, including sleep, mood, and pain. However, so far, the precise mechanisms by which MLT control the function of habenula neurons remain unknown. Using whole cell recordings from male rat brain slices, we examined the effects of MLT on the excitability of medial lateral habenula (MLHb) neurons. We found that MLT had no significant effects on the intrinsic excitability of MLHb neurons, but profoundly increased the amplitude of glutamate-mediated evoked excitatory post-synaptic currents (EPSC). The increase in strength of glutamate synapses onto MLHb neurons was mediated by an increase in glutamate release. The MLT-induced increase in glutamatergic synaptic transmission was blocked by the competitive MT1 /MT2 receptor antagonist luzindole (LUZ). These results unravel a potential cellular mechanism by which MLT receptor activation enhances the excitability of MLHb neurons. The MLT-mediated control of glutamatergic inputs to the MLHb may play a key role in the modulation of various behaviors controlled by the habenular complex. PMID:26799638

  8. Heavy metals and rare earth elements source-sink in some Egyptian cigarettes as determined by neutron activation analysis.

    PubMed

    Nada, A; Abdel-Wahab, M; Sroor, A; Abdel-Haleem, A S; Abdel-Sabour, M F

    1999-07-01

    Heavy metals and rare earth elements in two types of cigarettes were studied. The contents of trace elements were determined by using delayed neutron activation analysis. In the present study 11 elements have been detected in popular and fine brand cigarettes marketed in Egypt. Evaluation of these elements with their potential hazards for smokers is briefly discussed. The material balance (source and sink) for each element was determined. Also the ratio of element recovery to the total amount was assessed. PMID:10376325

  9. Role of Oxygen as Surface-Active Element in Linear GTA Welding Process

    NASA Astrophysics Data System (ADS)

    Yadaiah, Nirsanametla; Bag, Swarup

    2013-11-01

    Although the surface-active elements such as oxygen and sulfur have an adverse effect on momentum transport in liquid metals during fusion welding, such elements can be used beneficially up to a certain limit to increase the weld penetration in the gas tungsten arc (GTA) welding process. The fluid flow pattern and consequently the weld penetration and width change due to a change in coefficient of surface tension from a negative value to a positive value. The present work is focused on the analysis of possible effects of surface-active elements to change the weld pool dimensions in linear GTA welding. A 3D finite element-based heat transfer and fluid flow model is developed to study the effect of surface-active elements on stainless steel plates. A velocity in the order of 180 mm/s due to surface tension force is estimated at an optimum concentration of surface-active elements. Further, the differential evolution-based global optimization algorithm is integrated with the numerical model to estimate uncertain model parameters such as arc efficiency, effective arc radius, and effective values of material properties at high temperatures. The effective values of thermal conductivity and viscosity are estimated to be enhanced nine and seven times, respectively, over corresponding room temperature values. An error analysis is also performed to find out the overall reliability of the computed results, and a maximum reliability of 0.94 is achieved.

  10. IN-FLIGHT CAPTURE OF ELEMENTAL MERCURY BY A CHLORINE-IMPREGNATED ACTIVATED CARBON

    EPA Science Inventory

    The paper discusses the in-flight capture of elemental mercury (Hgo) by a chlorine (C1)-impregnated activated carbon. Efforts to develop sorbents for the control of Hg emissions have demonstrated that C1-impregnation of virgin activated carbons using dilute solutions of hydrogen ...

  11. IMPORTANCE OF ACTIVATED CARBON'S OXYGEN SURFACE FUNCTIONAL GROUPS ON ELEMENTAL MERCURY ADSORPTION

    EPA Science Inventory

    The effect of varying physical and chemical properties of activated carbons on adsorption of elemental mercury [Hg(0)] was studied by treating two activated carbons to modify their surface functional groups and pore structures. Heat treatment (1200 K) in nitrogen (N2), air oxidat...

  12. EFFECT OF MOISTURE ON ADSORPTION OF ELEMENTAL MERCURY BY ACTIVATED CARBON

    EPA Science Inventory

    The paper discusses experiments using activated carbon to capture elemental mercury (Hgo), and a bench-scale dixed-bed reactor and a flow reactor to determine the role of surface moisture in Hgo adsorption. Three activated-carbon samples, with different pore structure and ash co...

  13. DEVELOPMENT OF A CL-IMPREGNATED ACTIVATED CARBON FOR ENTRAINED-FLOW CAPTURE OF ELEMENTAL MERCURY

    EPA Science Inventory

    Efforts to discern the role of an activated carbon's surface functional groups on the adsorption of elemental mercury [Hg(0)] and mercuric chloride demonstrated that chlorine (Cl) impregnation of a virgin activated carbon using dilute solutions of hydrogen chloride leads to incre...

  14. Prediction of Geomagnetic Activity and Key Parameters in High-Latitude Ionosphere-Basic Elements

    NASA Technical Reports Server (NTRS)

    Lyatsky, W.; Khazanov, G. V.

    2007-01-01

    Prediction of geomagnetic activity and related events in the Earth's magnetosphere and ionosphere is an important task of the Space Weather program. Prediction reliability is dependent on the prediction method and elements included in the prediction scheme. Two main elements are a suitable geomagnetic activity index and coupling function -- the combination of solar wind parameters providing the best correlation between upstream solar wind data and geomagnetic activity. The appropriate choice of these two elements is imperative for any reliable prediction model. The purpose of this work was to elaborate on these two elements -- the appropriate geomagnetic activity index and the coupling function -- and investigate the opportunity to improve the reliability of the prediction of geomagnetic activity and other events in the Earth's magnetosphere. The new polar magnetic index of geomagnetic activity and the new version of the coupling function lead to a significant increase in the reliability of predicting the geomagnetic activity and some key parameters, such as cross-polar cap voltage and total Joule heating in high-latitude ionosphere, which play a very important role in the development of geomagnetic and other activity in the Earth s magnetosphere, and are widely used as key input parameters in modeling magnetospheric, ionospheric, and thermospheric processes.

  15. BENCH-SCALE INVESTIGATION OF MECHANISMS OF ELEMENTAL MERCURY CAPTURE BY ACTIVATED CARBON

    EPA Science Inventory

    The paper gives results of an investigation of the sorption and desorption of gaseous elemental mercury by activated carbon sorbents. wo sorbents were chosen for the study, one (PC-100) thermally activated and the other (HGR) chemically impregnated with sulfur. he sorbents had si...

  16. Binding among Select Episodic Elements Is Altered via Active Short-Term Retrieval

    ERIC Educational Resources Information Center

    Bridge, Donna J.; Voss, Joel L.

    2015-01-01

    Of the many elements that comprise an episode, are any disproportionately bound to the others? We tested whether active short-term retrieval selectively increases binding. Individual objects from multiobject displays were retrieved after brief delays. Memory was later tested for the other objects. Cueing with actively retrieved objects facilitated…

  17. Impact of detector-element active-area shape and fill factor on super-resolution

    NASA Astrophysics Data System (ADS)

    Hardie, Russell; Droege, Douglas; Dapore, Alexander; Greiner, Mark

    2015-05-01

    In many undersampled imaging systems, spatial integration from the individual detector elements is the dominant component of the system point spread function (PSF). Conventional focal plane arrays (FPAs) utilize square detector elements with a nearly 100% fill factor, where fill factor is defined as the fraction of the detector element area that is active in light detection. A large fill factor is generally considered to be desirable because more photons are collected for a given pitch, and this leads to a higher signal-to-noise-ratio (SNR). However, the large active area works against super-resolution (SR) image restoration by acting as an additional low pass filter in the overall PSF when modeled on the SR sampling grid. A high fill factor also tends to increase blurring from pixel cross-talk. In this paper, we study the impact of FPA detector-element shape and fill factor on SR. A detailed modulation transfer function analysis is provided along with a number of experimental results with both simulated data and real data acquired with a midwave infrared (MWIR) imaging system. We demonstrate the potential advantage of low fill factor detector elements when combined with SR image restoration. Our results suggest that low fill factor circular detector elements may be the best choice. New video results are presented using robust adaptive Wiener filter SR processing applied to data from a commercial MWIR imaging system with both high and low detector element fill factors.

  18. Survey of trace elements in coals and coal-related materials by neutron activation analysis

    USGS Publications Warehouse

    Ruch, R.R.; Cahill, R.A.; Frost, J.K.; Camp, L.R.; Gluskoter, H.J.

    1977-01-01

    Utilizing primarily instrumental neutron activation analysis (INAA) and other analytical methods as many as 61 elements were quantitatively surveyed in 170 U.S. whole coals, 70 washed coals, and 40 bench samples. Data on areal and vertical distributions in various regions were obtained along with extensive information on the mode of occurrence of various elements in the coal matrix itself. ?? 1977 Akade??miai Kiado??.

  19. Multi-element analysis of emeralds and associated rocks by k(o) neutron activation analysis

    PubMed

    Acharya; Mondal; Burte; Nair; Reddy; Reddy; Reddy; Manohar

    2000-12-01

    Multi-element analysis was carried out in natural emeralds, their associated rocks and one sample of beryl obtained from Rajasthan, India. The concentrations of 21 elements were assayed by Instrumental Neutron Activation Analysis using the k0 method (k0 INAA method) and high-resolution gamma ray spectrometry. The data reveal the segregation of some elements from associated (trapped and host) rocks to the mineral beryl forming the gemstones. A reference rock standard of the US Geological Survey (USGS BCR-1) was also analysed as a control of the method. PMID:11077961

  20. Determination of Interesting Toxicological Elements in PM2.5 by Neutron and Photon Activation Analysis

    PubMed Central

    Capannesi, Geraldo; Lopez, Francesco

    2013-01-01

    Human activities introduce compounds increasing levels of many dangerous species for environment and population. In this way, trace elements in airborne particulate have a preeminent position due to toxic element presence affecting the biological systems. The main problem is the analytical determination of such species at ultratrace levels: a very specific methodology is necessary with regard to the accuracy and precision and contamination problems. Instrumental Neutron Activation Analysis and Instrumental Photon Activation Analysis assure these requirements. A retrospective element analysis in airborne particulate collected in the last 4 decades has been carried out for studying their trend. The samples were collected in urban location in order to determine only effects due to global aerosol circulation; semiannual samples have been used to characterize the summer/winter behavior of natural and artificial origin. The levels of natural origin element are higher than those in other countries owing to geological and meteorological factors peculiar to Central Italy. The levels of artificial elements are sometimes less than those in other countries, suggesting a less polluted general situation for Central Italy. However, for a few elements (e.g., Pb) the levels measured are only slight lower than those proposed as air ambient standard. PMID:23878525

  1. Identification of three kinds of mutually related composite elements conferring S phase-specific transcriptional activation.

    PubMed

    Taoka, K; Kaya, H; Nakayama, T; Araki, T; Meshi, T; Iwabuchi, M

    1999-06-01

    Conservation of the Oct motif (CGCGGATC) is a remarkable feature of plant histone gene promoters. Many of the Oct motifs are paired with a distinct motif, Hex, TCA or CCAAT-box, constituting the type I element (CCACGTCANCGATCCGCG), type II element (TCACGCGGATC) and type III element (GATCCGCG-N14-ACCAATCA). To clarify the roles of these Oct-containing composite elements (OCEs) in cell cycle-dependent and tissue-specific expression, we performed gain-of-function experiments with transgenic tobacco cell lines and plants harboring a derivative of the 35S core promoter/beta-glucuronidase fusion gene in which three or four copies of an OCE had been placed upstream. Although their activities were slightly different, results showed that each of the three types of OCEs could confer the ability to direct S phase-specific expression on a heterologous promoter. In transgenic plants, the type I and III elements exhibited a similar activity, directing expression in meristematic tissues, whereas the activity of the type II element appeared to be restricted to young cotyledons and maturating guard cells. Mutational analyses demonstrated that the co-operation of Oct with another module (Hex, TCA or CCAAT-box) was absolutely required for both temporal and spatial regulation. Thus, OCEs play a pivotal role in regulation of the expression of plant histone genes. PMID:10417712

  2. Advanced semi-active engine and transmission mounts: tools for modelling, analysis, design, and tuning

    NASA Astrophysics Data System (ADS)

    Farjoud, Alireza; Taylor, Russell; Schumann, Eric; Schlangen, Timothy

    2014-02-01

    This paper is focused on modelling, design, and testing of semi-active magneto-rheological (MR) engine and transmission mounts used in the automotive industry. The purpose is to develop a complete analysis, synthesis, design, and tuning tool that reduces the need for expensive and time-consuming laboratory and field tests. A detailed mathematical model of such devices is developed using multi-physics modelling techniques for physical systems with various energy domains. The model includes all major features of an MR mount including fluid dynamics, fluid track, elastic components, decoupler, rate-dip, gas-charged chamber, MR fluid rheology, magnetic circuit, electronic driver, and control algorithm. Conventional passive hydraulic mounts can also be studied using the same mathematical model. The model is validated using standard experimental procedures. It is used for design and parametric study of mounts; effects of various geometric and material parameters on dynamic response of mounts can be studied. Additionally, this model can be used to test various control strategies to obtain best vibration isolation performance by tuning control parameters. Another benefit of this work is that nonlinear interactions between sub-components of the mount can be observed and investigated. This is not possible by using simplified linear models currently available.

  3. Anoctamin Calcium-Activated Chloride Channels May Modulate Inhibitory Transmission in the Cerebellar Cortex.

    PubMed

    Zhang, Weiping; Schmelzeisen, Steffen; Parthier, Daniel; Frings, Stephan; Möhrlen, Frank

    2015-01-01

    Calcium-activated chloride channels of the anoctamin (alias TMEM16) protein family fulfill critical functions in epithelial fluid transport, smooth muscle contraction and sensory signal processing. Little is known, however, about their contribution to information processing in the central nervous system. Here we examined the recent finding that a calcium-dependent chloride conductance impacts on GABAergic synaptic inhibition in Purkinje cells of the cerebellum. We asked whether anoctamin channels may underlie this chloride conductance. We identified two anoctamin channel proteins, ANO1 and ANO2, in the cerebellar cortex. ANO1 was expressed in inhibitory interneurons of the molecular layer and the granule cell layer. Both channels were expressed in Purkinje cells but, while ANO1 appeared to be retained in the cell body, ANO2 was targeted to the dendritic tree. Functional studies confirmed that ANO2 was involved in a calcium-dependent mode of ionic plasticity that reduces the efficacy of GABAergic synapses. ANO2 channels attenuated GABAergic transmission by increasing the postsynaptic chloride concentration, hence reducing the driving force for chloride influx. Our data suggest that ANO2 channels are involved in a Ca2+-dependent regulation of synaptic weight in GABAergic inhibition. Thus, in balance with the chloride extrusion mechanism via the co-transporter KCC2, ANO2 appears to regulate ionic plasticity in the cerebellum. PMID:26558388

  4. Anoctamin Calcium-Activated Chloride Channels May Modulate Inhibitory Transmission in the Cerebellar Cortex

    PubMed Central

    Parthier, Daniel; Frings, Stephan; Möhrlen, Frank

    2015-01-01

    Calcium-activated chloride channels of the anoctamin (alias TMEM16) protein family fulfill critical functions in epithelial fluid transport, smooth muscle contraction and sensory signal processing. Little is known, however, about their contribution to information processing in the central nervous system. Here we examined the recent finding that a calcium-dependent chloride conductance impacts on GABAergic synaptic inhibition in Purkinje cells of the cerebellum. We asked whether anoctamin channels may underlie this chloride conductance. We identified two anoctamin channel proteins, ANO1 and ANO2, in the cerebellar cortex. ANO1 was expressed in inhibitory interneurons of the molecular layer and the granule cell layer. Both channels were expressed in Purkinje cells but, while ANO1 appeared to be retained in the cell body, ANO2 was targeted to the dendritic tree. Functional studies confirmed that ANO2 was involved in a calcium-dependent mode of ionic plasticity that reduces the efficacy of GABAergic synapses. ANO2 channels attenuated GABAergic transmission by increasing the postsynaptic chloride concentration, hence reducing the driving force for chloride influx. Our data suggest that ANO2 channels are involved in a Ca2+-dependent regulation of synaptic weight in GABAergic inhibition. Thus, in balance with the chloride extrusion mechanism via the co-transporter KCC2, ANO2 appears to regulate ionic plasticity in the cerebellum. PMID:26558388

  5. Location of active transmission sites of Schistosoma japonicum in lake and marshland regions in China.

    PubMed

    Zhang, Z J; Carpenter, T E; Lynn, H S; Chen, Y; Bivand, R; Clark, A B; Hui, F M; Peng, W X; Zhou, Y B; Zhao, G M; Jiang, Q W

    2009-06-01

    Schistosomiasis control in China has, in general, been very successful during the past several decades. However, the rebounding of the epidemic situation in some areas in recent years raises concerns about a sustainable control strategy of which locating active transmission sites (ATS) is a necessary first step. This study presents a systematic approach for locating schistosomiasis ATS by combining the approaches of identifying high risk regions for schisotosmiasis and extracting snail habitats. Environmental, topographical, and human behavioural factors were included in the model. Four significant high-risk regions were detected and 6 ATS were located. We used the normalized difference water index (NDWI) combined with the normalized difference vegetation index (NDVI) to extract snail habitats, and the pointwise 'P-value surface' approach to test statistical significance of predicted disease risk. We found complicated non-linear relationships between predictors and schistosomiasis risk, which might result in serious biases if data were not properly treated. We also found that the associations were related to spatial scales, indicating that a well-designed series of studies were needed to relate the disease risk with predictors across various study scales. Our approach provides a useful tool, especially in the field of vector-borne or environment-related diseases. PMID:19416552

  6. Acute lipopolysaccharide exposure facilitates epileptiform activity via enhanced excitatory synaptic transmission and neuronal excitability in vitro

    PubMed Central

    Gao, Fei; Liu, Zhiqiang; Ren, Wei; Jiang, Wen

    2014-01-01

    Growing evidence indicates brain inflammation has been involved in the genesis of seizures. However, the direct effect of acute inflammation on neuronal circuits is not well known. Lipopolysaccharide (LPS) has been used extensively to stimulate brain inflammatory responses both in vivo and in vitro. Here, we observed the contribution of inflammation induced by 10 μg/mL LPS to the excitability of neuronal circuits in acute hippocampal slices. When slices were incubated with LPS for 30 minutes, significant increased concentration of tumor necrosis factor α and interleukin 1β were detected by enzyme-linked immunosorbent assay. In electrophysiological recordings, we found that frequency of epileptiform discharges and spikes per burst increased 30 minutes after LPS application. LPS enhanced evoked excitatory postsynaptic currents but did not modify evoked inhibitory postsynaptic currents. In addition, exposure to LPS enhanced the excitability of CA1 pyramidal neurons, as demonstrated by a decrease in rheobase and an increase in action potential frequency elicited by depolarizing current injection. Our observations suggest that acute inflammation induced by LPS facilitates epileptiform activity in vitro and that enhancement of excitatory synaptic transmission and neuronal excitability may contribute to this facilitation. These results may provide new clues for treating seizures associated with brain inflammatory disease. PMID:25170268

  7. 77 FR 24950 - Meeting Related to the Transmission Planning Activities of the Southwest Power Pool, Inc.; Notice...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-26

    ... Energy Regulatory Commission Meeting Related to the Transmission Planning Activities of the Southwest Power Pool, Inc.; Notice of Commission Staff Attendance The Federal Energy Regulatory Commission hereby gives notice that members of the Commission's staff may attend the following meeting related to...

  8. Study on the activated laser welding of ferritic stainless steel with rare earth elements yttrium

    NASA Astrophysics Data System (ADS)

    Wang, Yonghui; Hu, Shengsun; Shen, Junqi

    2015-10-01

    The ferritic stainless steel SUS430 was used in this work. Based on a multi-component activating flux, composed of 50% ZrO2, 12.09 % CaCO3, 10.43 % CaO, and 27.49 % MgO, a series of modified activating fluxes with 0.5%, 1%, 2%, 5%, 10%, 15%, and 20% of rare earth (RE) element yttrium (Y) respectively were produced, and their effects on the weld penetration (WP) and corrosion resistant (CR) property were studied. Results showed that RE element Y hardly had any effects on increasing the WP. In the FeCl3 spot corrosion experiment, the corrosion rates of almost all the samples cut from welded joints turned out to be greater than the parent metal (23.51 g/m2 h). However, there was an exception that the corrosion rate of the sample with 5% Y was only 21.96 g/m2 h, which was even better than parent metal. The further Energy Dispersive Spectrometer (EDS) test showed the existence of elements Zr, Ca, O, and Y in the molten slag near the weld seam while none of them were found in the weld metal, indicating the direct transition of element from activating fluxes to the welding seam did not exist. It was known that certain composition of activating fluxes effectively restrain the loss of Cr element in the process of laser welding, and as a result, the CR of welded joints was improved.

  9. Synthetic promoter elements obtained by nucleotide sequence variation and selection for activity

    PubMed Central

    Edelman, Gerald M.; Meech, Robyn; Owens, Geoffrey C.; Jones, Frederick S.

    2000-01-01

    Eukaryotic transcriptional regulation in different cells involves large numbers and arrangements of cis and trans elements. To survey the number of cis regulatory elements that are active in different contexts, we have devised a high-throughput selection procedure permitting synthesis of active cis motifs that enhance the activity of a minimal promoter. This synthetic promoter construction method (SPCM) was used to identify >100 DNA sequences that showed increased promoter activity in the neuroblastoma cell line Neuro2A. After determining DNA sequences of selected synthetic promoters, database searches for known elements revealed a predominance of eight motifs: AP2, CEBP, GRE, Ebox, ETS, CREB, AP1, and SP1/MAZ. The most active of the selected synthetic promoters contain composites of a number of these motifs. Assays of DNA binding and promoter activity of three exemplary motifs (ETS, CREB, and SP1/MAZ) were used to prove the effectiveness of SPCM in uncovering active sequences. Up to 10% of 133 selected active sequences had no match in currently available databases, raising the possibility that new motifs and transcriptional regulatory proteins to which they bind may be revealed by SPCM. The method may find uses in constructing databases of active cis motifs, in diagnostics, and in gene therapy. PMID:10725347

  10. Trace Elements Affect Methanogenic Activity and Diversity in Enrichments from Subsurface Coal Bed Produced Water

    PubMed Central

    Ünal, Burcu; Perry, Verlin Ryan; Sheth, Mili; Gomez-Alvarez, Vicente; Chin, Kuk-Jeong; Nüsslein, Klaus

    2012-01-01

    Microbial methane from coal beds accounts for a significant and growing percentage of natural gas worldwide. Our knowledge of physical and geochemical factors regulating methanogenesis is still in its infancy. We hypothesized that in these closed systems, trace elements (as micronutrients) are a limiting factor for methanogenic growth and activity. Trace elements are essential components of enzymes or cofactors of metabolic pathways associated with methanogenesis. This study examined the effects of eight trace elements (iron, nickel, cobalt, molybdenum, zinc, manganese, boron, and copper) on methane production, on mcrA transcript levels, and on methanogenic community structure in enrichment cultures obtained from coal bed methane (CBM) well produced water samples from the Powder River Basin, Wyoming. Methane production was shown to be limited both by a lack of additional trace elements as well as by the addition of an overly concentrated trace element mixture. Addition of trace elements at concentrations optimized for standard media enhanced methane production by 37%. After 7 days of incubation, the levels of mcrA transcripts in enrichment cultures with trace element amendment were much higher than in cultures without amendment. Transcript levels of mcrA correlated positively with elevated rates of methane production in supplemented enrichments (R2 = 0.95). Metabolically active methanogens, identified by clone sequences of mcrA mRNA retrieved from enrichment cultures, were closely related to Methanobacterium subterraneum and Methanobacterium formicicum. Enrichment cultures were dominated by M. subterraneum and had slightly higher predicted methanogenic richness, but less diversity than enrichment cultures without amendments. These results suggest that varying concentrations of trace elements in produced water from different subsurface coal wells may cause changing levels of CBM production and alter the composition of the active methanogenic community. PMID

  11. Semi-automatic transmission

    SciTech Connect

    Morscheck, T.J.; Davis, A.R.; Huggins, M.J.

    1987-06-30

    This patent describes a semi-automatic mechanical change gear transmission system of the type comprising: a mechanical change gear transmission of the type comprising a transmission housing, an input shaft rotatably supported in the housing and driven by an engine through a nonpositive coupling, an output shaft rotatably supported in the housing and a plurality of selectable ratio gears selectively engageable one at a time to a first transmission element by means of positive, nonsynchronized jaw clutch assemblies for providing a plurality of manually selectable drive ratios between the input and output shafts, each of the jaw clutch assemblies comprising a first jaw clutch member rotatably associated with the first transmission element and a second jaw clutch member rotatably associated with a second transmission element, each of the first jaw clutch members axially moveable relative to the first transmission element; manually operated means for engaging and disengaging the nonpositive coupling; manually operated shifting means for engaging selected ratio gears to and disengaging selected ratio gears from the first transmission element; selection for sensing the identity of the particular ratio gear selected for manual engagement or disengagement from the first transmission element and for providing a signal; first and second rotational speed sensors for sensing the rotational speed of the first and second transmission elements and providing signals; a power synchronizer assembly selectively actuable for selectively varying the rotational speed of the second transmission element and the second jaw clutch members rotatably associated therewith; and a central processing unit semi-automatic mechanical change gear transmission system.

  12. Relationships between locomotor activation and alterations in brain temperature during selective blockade and stimulation of dopamine transmission.

    PubMed

    Brown, P L; Bae, D; Kiyatkin, E A

    2007-03-01

    It is well known that the dopamine (DA) system plays an essential role in the organization and regulation of brain activational processes. Various environmental stimuli that induce locomotor activation also increase DA transmission, while DA antagonists decrease spontaneous locomotion. Our previous work supports close relationships between locomotor activation and brain and body temperature increases induced by salient environmental challenges or occurring during motivated behavior. While this correlation was also true for psychomotor stimulant drugs such as methamphetamine and MDMA, more complex relationships or even inverted correlations were found for other drugs that are known to increase DA transmission (i.e. heroin and cocaine). In the present study we examined brain, muscle and skin temperatures together with conventional locomotion during selective interruption of DA transmission induced by a mixture of D1 and D2 antagonists (SCH-23390 and eticlopride at 0.2 mg/kg, s.c.) and its selective activation by apomorphine (APO; 0.05 and 0.25 mg/kg, i.v.) in rats. While full DA receptor blockade decreased spontaneous locomotion, it significantly increased brain, muscle and skin temperatures, suggesting metabolic brain activation under conditions of vasodilatation (or weakening of normal vascular tone). In contrast, APO strongly decreased skin temperature but tended to decrease brain and muscle temperatures despite strong hyperlocomotion and stereotypy. The brain temperature response to APO was strongly dependent on basal brain temperature, with hypothermia at high basal temperatures and weak hyperthermia at low temperatures. While supporting the role of DA in locomotor activation, these data suggest more complex relationships between drug-induced alterations in DA transmission, behavioral activation and metabolic brain activation. PMID:17196751

  13. Integrator element as a promoter of active learning in engineering teaching

    NASA Astrophysics Data System (ADS)

    Oliveira, Paulo C.; Oliveira, Cristina G.

    2014-03-01

    In this paper, we present a teaching proposal used in an Introductory Physics course to civil engineering students from Porto's Engineering Institute/Instituto Superior de Engenharia do Porto (ISEP). The proposal was born from the need to change students' perception and motivation for learning physics. It consists in the use of an integrator element, called the physics elevator project. This integrator element allows us to use, in a single project, all the content taught in the course and uses several active learning strategies. In this paper, we analyse this project as: (i) a clarifying element of the contents covered in the course; (ii) a promoter element of motivation and active participation in class and finally and (iii) a link between the contents covered in the course and the 'real world'. The data were collected by a questionnaire and interviews to students. From the data collected, it seems that the integrator element improves students' motivation towards physics and develops several skills that they consider to be important to their professional future. It also acts as a clarifying element and makes the connection between the physics that is taught and the 'real world'.

  14. Studies of generalized elemental imbalances in neurological disease patients using INAA (instrumental neutron activation analysis)

    SciTech Connect

    Ehmann, W.D.; Vance, D.E.; Khare, S.S.; Kasarskis, E.J.; Markesbery, W.R.

    1988-01-01

    Evidence has been presented in the literature to implicate trace elements in the etiology of several age-related neurological diseases. Most of these studies are based on brain analyses. Using instrumental neutron activation analysis (INAA), we have observed trace element imbalances in brains of patients with Alzheimer's disease, amyotrophic lateral sclerosis (ALS), and Picks's disease. The most prevalent elemental imbalances found in the brain were for bromine, mercury, and the alkali metals. In this study the authors report INAA studies of trace elements in nonneural tissues from Alzheimer's disease and ALS patients. Samples from household relatives were collected for use as controls wherever possible. Hair samples were washed according to the International Atomic Energy Agency recommended procedure. Fingernail samples were scraped with a quartz knife prior to washing by the same procedure. For ALS patients, blood samples were also collected. These data indicate that elemental imbalances in Alzheimer's disease and ALS are not restricted to the brain. Many elements perturbed in the brain are also altered in the several nonneural tissues examined to date. The imbalances in different tissues, however, are not always in the same direction. The changes observed may represent causes, effects, or simply epiphenomena. Longitudinal studies of nonneural tissues and blood, as well as tissue microprobe analyses at the cellular and subcellular level, will be required in order to better assess the role of trace elements in the etiology of these diseases.

  15. Electrically active light-element complexes in silicon crystals grown by cast method

    NASA Astrophysics Data System (ADS)

    Sato, Kuniyuki; Ogura, Atsushi; Ono, Haruhiko

    2016-09-01

    Electrically active light-element complexes called thermal donors and shallow thermal donors in silicon crystals grown by the cast method were studied by low-temperature far-infrared absorption spectroscopy. The relationship between these complexes and either crystal defects or light-element impurities was investigated by comparing different types of silicon crystals, that is, conventional cast-grown multicrystalline Si, seed-cast monolike-Si, and Czochralski-grown Si. The dependence of thermal and the shallow thermal donors on the light-element impurity concentration and their annealing behaviors were examined to compare the crystals. It was found that crystal defects such as dislocations and grain boundaries did not affect the formation of thermal or shallow thermal donors. The formation of these complexes was dominantly affected by the concentration of light-element impurities, O and C, independent of the existence of crystal defects.

  16. Effect of Active Case Finding on Prevalence and Transmission of Pulmonary Tuberculosis in Dhaka Central Jail, Bangladesh

    PubMed Central

    Banu, Sayera; Rahman, Md. Toufiq; Uddin, Mohammad Khaja Mafij; Khatun, Razia; Khan, Md. Siddiqur Rahman; Rahman, Md. Mojibur; Uddin, Syed Iftekhar; Ahmed, Tahmeed; Heffelfinger, James D.

    2015-01-01

    Background Understanding tuberculosis (TB) transmission dynamics is essential for establishing effective TB control strategies in settings where the burden and risk of transmission are high. The objectives of this study were to evaluate the effect of active screening on controlling TB transmission and also to characterize Mycobacterium tuberculosis strains for investigating transmission dynamics in a correctional setting. Methods The study was carried out in Dhaka Central Jail (DCJ), from October 2005 to February 2010. An active case finding strategy for pulmonary TB was established both at the entry point to the prison and inside the prison. Three sputum specimens were collected from all pulmonary TB suspects and subjected to smear microscopy, culture, and drug susceptibility testing as well as genotyping which included deletion analysis, spoligotyping and analysis of mycobacterial interspersed repetitive units (MIRU). Results A total of 60,585 inmates were screened during the study period. We found 466 inmates with pulmonary TB of whom 357 (77%) had positive smear microscopy results and 109 (23%) had negative smear microscopy results but had positive results on culture. The number of pulmonary TB cases declined significantly, from 49 cases during the first quarter to 8 cases in the final quarter of the study period (p=0.001). Deletion analysis identified all isolates as M. tuberculosis and further identified 229 (70%) strains as ‘modern’ and 100 (30%) strains as ‘ancestral’. Analysis of MIRU showed that 347 strains (85%) exhibited unique patterns, whereas 61 strains (15%) clustered into 22 groups. The largest cluster comprised eight strains of the Beijing M. tuberculosis type. The rate of recent transmission was estimated to be 9.6%. Conclusions Implementation of active screening for TB was associated with a decline in TB cases in DCJ. Implementation of active screening in prison settings might substantially reduce the national burden of TB in Bangladesh

  17. Elemental characterization of Hazm El-Jalamid phosphorite by instrumental neutron activation analysis.

    PubMed

    El-Taher, A; Khater, Ashraf E M

    2016-08-01

    Instrumental neutron activation analyses (INAA) have been used to achieve accurate knowledge about the elemental analysis of phosphate ore deposits collected from Hazm El-Jalamid Northeast of Saudi Arabia. The samples were prepared for irradiation by thermal neutrons using a thermal neutron flux of 7×10(12)ncm(-2)s(-1) at ACT Lab Canada. The concentrations of 19 elements were determined. These included 12 major, minor and trace elements (Au, As, Ba, Br, Cr, Mo, Sb, Sc, Sr, Th, U and Zn) and 7 rare earth elements (REEs) (La, Ce, Nd, Sm, Eu, Yb and Lu). Major elements (Si, Al, Fe, Ca, Mg, Na, K, Cr, Ti, Mn, P, Sr and Ba) were determined using an inductively coupled plasma-mass spectrometer (ICP-MS). The comparison of the concentration of U and the REEs in the Hazm El-Jalamid phosphate samples with those of the Umm Wu'al phosphate from Saudi Arabia and El-Sibayia and El Hamrawein phosphate from Egypt shows that the contents of U and REEs are clearly higher in the Umm Wu'al, El-Sibayia and El Hamrawein phosphates than in the Hazm El-Jalamid phosphate samples. The results of major, trace elements, uranium and rare earth elements (REE) from El Jalamid phosphate have been compared with the global values of these elements. The concentrations for most of the elements studied are lower than the concentrations reported in the literature. The acquired data will serve as a reference for the follow-up studies to assess the agronomic effectiveness of the Hazm El-Jalamid phosphate rocks. PMID:27235886

  18. Overabundance of s-process elements in the atmosphere of the active red giant PZ Mon

    NASA Astrophysics Data System (ADS)

    Pakhomov, Yu. V.

    2015-11-01

    Based on high-resolution ( R = 60 000) spectra taken with the NES spectrograph (the 6-m BTA telescope, the Special Astrophysical Observatory of the Russian Academy of Sciences), we have determined the abundances of 26 elements, from lithium to europium, in the atmosphere of the active red giant PZ Mon, which belongs to the class of RS CVn variable stars, by the method of model stellar atmospheres. We have taken into account the hyperfine splitting, the isotopic shift, and the departure from local thermodynamic equilibrium. Analysis of our data has revealed an overabundance of lithium and neutron-capture elements compared to normal red giants. For lithium, this is explained by the activity of the star, while the overabundance of s-elements is presumably similar in nature to that inmild bariumstars.

  19. Spontaneous activity in the developing gerbil auditory cortex in vivo involves GABAergic transmission

    PubMed Central

    Kotak, Vibhakar C.; Péndola, L. Martín; Rodríguez-Contreras, Adrián

    2012-01-01

    A salient feature of the developing brain is that spontaneous oscillations (SOs) and waves may influence the emergence of synaptic connections. Whilst gamma-amino butyric acid (GABA) produces depolarization and may support SOs in the neurons of developing rodents, it elicits hyperpolarization and diminishes SOs in developing gerbil auditory cortex (ACx). Therefore, we asked whether SOs exist in developing gerbil ACx in vivo and if GABAergic involvement can be manipulated. In vivo extracellular recordings in P3-5 ACx revealed SOs with longer burst durations and shorter inter-event intervals compared to ACx SOs in slices. ACx was then validated by gross anatomical features and lesions created at the in vivo recording site that corresponded with the electrophysiological coordinates of thalamorecipient ACx in slices. Further, NeuroVue Red, a lipophilic dye loaded at the in vivo recording sites, stained anatomically identifiable fiber tracks between the ACx and the auditory thalamus, medial geniculate body (MG). Separately, to chronically perturb GABAergic role in SOs, P2-5 pups were administered daily with GABAA receptor blocker, bicuculline (BIC). We then recorded from P14-17 ACx neurons in slices generated after hearing onset. ACx neurons from BIC-administered pups exhibited spontaneous action potentials in contrast to subthreshold synaptic potentials in neurons from sham-injected animals. Finally, to elucidate whether the gap junction blocker mefloquine (MFQ) previously shown to dampen ACx SOs in slices affected GABAergic transmission, MFQ was acutely applied in P3-5 slices while spontaneous inhibitory postsynaptic currents (sIPSCs) were recorded. Whereas MFQ increased the amplitude and frequency of sIPSCs in ACx neurons, the broad-spectrum gap junction blocker carbenoxolone decreased sIPSC amplitudes only. Together, we show that P2-5 gerbil ACx can endogenously generate SOs in vivo. Persistence of activity in ACx in P14-17 slices from pups administered with BIC at

  20. The Element Effect Revisited: Factors Determining Leaving Group Ability in Activated Nucleophilic Aromatic Substitution Reactions

    PubMed Central

    Senger, Nicholas A.; Bo, Bo; Cheng, Qian; Keeffe, James R.; Gronert, Scott; Wu, Weiming

    2012-01-01

    The “element effect” in nucleophilic aromatic substitution reactions (SNAr) is characterized by the leaving group order, F > NO2 > Cl ≈ Br > I, in activated aryl halides. Multiple causes for this result have been proposed. Experimental evidence shows that the element effect order in the reaction of piperidine with 2,4-dinitrophenyl halides in methanol is governed by the differences in enthalpies of activation. Computational studies of the reaction of piperidine and dimethylamine with the same aryl halides using the polarizable continuum model (PCM) for solvation indicate that polar, polarizability, solvation, and negative hyperconjugative effects are all of some importance in producing the element effect in methanol. In addition, a reversal of polarity of the C–X bond from reactant to transition state in the case of ArCl and ArBr compared to ArF also contributes to their difference in reactivity. The polarity reversal, and hyperconjugative influences have received little or no attention in the past. Nor has differential solvation of the different transition states been strongly emphasized. An anionic nucleophile, thiolate, gives very early transition states and negative activation enthalpies with activated aryl halides. The element effect is not established for these reactions. We suggest that the leaving group order in the gas phase will be dependent on the exact combination of nucleophile, leaving group, and substrate framework. The geometry of the SNAr transition state permits useful, qualitative conceptual distinctions to be made between this reaction and other modes of nucleophilic attack. PMID:23057717

  1. Measurement of the gain in a disk amplification stage with neodymium phosphate glass active elements

    SciTech Connect

    Voronich, Ivan N; Galakhov, I V; Garanin, Sergey G; Eroshenko, V A; Zaretskii, Aleksei I; Zimalin, B G; Ignat'ev, Ivan V; Kirdyashkin, M Yu; Kirillov, G A; Osin, Vladimir A; Rukavishnikov, N N; Sukharev, Stanislav A; Sharov, Oleg A; Charukhchev, Aleksandr V

    2003-06-30

    The measuring technique is described and time-resolved measurements of the small-signal gain as a function of the pump energy in a disk amplification stage with neodymium phosphate glass active elements in the 'Luch' facility are presented. The distribution of the gain over the amplifier aperture in the horizontal plane is measured. (lasers)

  2. Development of an active truss element for control of precision structures

    NASA Technical Reports Server (NTRS)

    Anderson, Eric H.; Moore, Donald M.; Fanson, James L.; Ealey, Mark A.

    1990-01-01

    An active structural element for use in precision control of large space structures is described. The active member is intended to replace a passive strut in a truss-like structure. It incorporates an eddy current displacement sensor and an actuator that is either piezoelectric (PZT) or electrostrictive (PMN). The design of the device is summarized. Performance of separate PZT and PMN actuators is compared for several properties relevant to submicrometer control of precision structures.

  3. Numerical investigation of sound transmission through double wall cylinders with respect to active noise control

    NASA Astrophysics Data System (ADS)

    Coats, T. J.; Silcox, R. J.; Lester, H. C.

    Market pressure for more fuel efficient air travel has led to increased use of turboprop and higher bypass turbofan engines. The low frequency components of propeller, jet and boundary layer noise are difficult to attenuate with conventional passive techniques. Weight and geometric restrictions for sound absorbing meterials limit the amount and type of treatment that may be applied. An active noise control (ANC) method is providing to be an attractive alternative. The approach taken in this paper uses a numerical finite/boundary element method (FEM/BEM) that may be easilty adapted to arbitrary geometries. A double walled cylinder is modeled using commercially available software. The outer shell is modeled as an aluminum cylinder, similar to that of aircraft skins. The inner shell is modeled as a composite material representative of a lightweight, stiff trim panel. Two different inner shell materials are used. The first is representative of current trim structure, the second a much stiffer composite. The primary source is generated by an exterior acoustic monopole. Control fields are generated using normal force inputs to the inner cylindrical shell. A linear least mean square (LMS) algorithm is used to determine amplitudes of control forces that minimize the interior acoustic field. Coupling of acoustic and structural modes and noise reductions are discussed for each of the inner shell materials.

  4. Numerical investigation of sound transmission through double wall cylinders with respect to active noise control

    NASA Technical Reports Server (NTRS)

    Coats, T. J.; Silcox, R. J.; Lester, H. C.

    1993-01-01

    Market pressure for more fuel efficient air travel has led to increased use of turboprop and higher bypass turbofan engines. The low frequency components of propeller, jet and boundary layer noise are difficult to attenuate with conventional passive techniques. Weight and geometric restrictions for sound absorbing meterials limit the amount and type of treatment that may be applied. An active noise control (ANC) method is providing to be an attractive alternative. The approach taken in this paper uses a numerical finite/boundary element method (FEM/BEM) that may be easilty adapted to arbitrary geometries. A double walled cylinder is modeled using commercially available software. The outer shell is modeled as an aluminum cylinder, similar to that of aircraft skins. The inner shell is modeled as a composite material representative of a lightweight, stiff trim panel. Two different inner shell materials are used. The first is representative of current trim structure, the second a much stiffer composite. The primary source is generated by an exterior acoustic monopole. Control fields are generated using normal force inputs to the inner cylindrical shell. A linear least mean square (LMS) algorithm is used to determine amplitudes of control forces that minimize the interior acoustic field. Coupling of acoustic and structural modes and noise reductions are discussed for each of the inner shell materials.

  5. Transmission-blocking activity is determined by transmission-reducing activity and number of control oocysts in Plasmodium falciparum standard membrane-feeding assay.

    PubMed

    Miura, Kazutoyo; Swihart, Bruce J; Deng, Bingbing; Zhou, Luwen; Pham, Thao P; Diouf, Ababacar; Burton, Timothy; Fay, Michael P; Long, Carole A

    2016-07-29

    Malaria transmission-blocking vaccines (TBVs) are potentially helpful tools for malaria eradication. The standard membrane-feeding assay (SMFA) is considered one of the "gold standard" assays for TBV development. However, lack of consensus in reporting results from SMFA has made it very challenging to compare results from different studies. Two main readouts, % inhibition in mean oocyst count per mosquito (TRA) and % inhibition in prevalence of infected mosquitoes (TBA), have been used widely. In this study, we statistically modeled the oocyst data in SMFA using data from 105 independent feeding experiments including 9804 mosquitoes. The model was validated using an independent data set that included 10,790 mosquitoes from 110 feeding studies. The model delineates a relationship between TRA, the mean oocyst count in the control mosquitoes (mo-contl), and TBA. While TRA was independent from mo-contl, TBA values changed depending on mo-contl. Regardless of monoclonal or polyclonal antibodies tested, there were strong concordances between observed TBA and predicted TBA based on the model using mo-contl and observed TRA. Simulations showed that SMFA with lower true control means had increased uncertainty in TRA estimates. The strong linkage between TBA, TRA and mo-contl inspired creation of a standardized TBA, a model-based TBA standardized to a target control mean, which allows comparison across multiple feeds regardless of mo-contl. This is the first study showing that the observed TBA can be reasonably predicted by mo-contl and the TRA of the test antibody using independent experimental data. This study indicates that TRA should be used to compare results from multiple feeds with different levels of mo-contl. If a measure of TBA is desired, it is better to report standardized TBA rather than observed TBA. These recommendations support rational comparisons of results from different studies, thus benefiting future TBV development. PMID:27372156

  6. Virus factories of cauliflower mosaic virus are virion reservoirs that engage actively in vector transmission.

    PubMed

    Bak, Aurélie; Gargani, Daniel; Macia, Jean-Luc; Malouvet, Enrick; Vernerey, Marie-Stéphanie; Blanc, Stéphane; Drucker, Martin

    2013-11-01

    Cauliflower mosaic virus (CaMV) forms two types of inclusion bodies within infected plant cells: numerous virus factories, which are the sites for viral replication and virion assembly, and a single transmission body (TB), which is specialized for virus transmission by aphid vectors. The TB reacts within seconds to aphid feeding on the host plant by total disruption and redistribution of its principal component, the viral transmission helper protein P2, onto microtubules throughout the cell. At the same time, virions also associate with microtubules. This redistribution of P2 and virions facilitates transmission and is reversible; the TB reforms within minutes after vector departure. Although some virions are present in the TB before disruption, their subsequent massive accumulation on the microtubule network suggests that they also are released from virus factories. Using drug treatments, mutant viruses, and exogenous supply of viral components to infected protoplasts, we show that virions can rapidly exit virus factories and, once in the cytoplasm, accumulate together with the helper protein P2 on the microtubule network. Moreover, we show that during reversion of this phenomenon, virions from the microtubule network can either be incorporated into the reverted TB or return to the virus factories. Our results suggest that CaMV factories are dynamic structures that participate in vector transmission by controlled release and uptake of virions during TB reaction. PMID:24006440

  7. Insight into GATA1 transcriptional activity through interrogation of cis elements disrupted in human erythroid disorders.

    PubMed

    Wakabayashi, Aoi; Ulirsch, Jacob C; Ludwig, Leif S; Fiorini, Claudia; Yasuda, Makiko; Choudhuri, Avik; McDonel, Patrick; Zon, Leonard I; Sankaran, Vijay G

    2016-04-19

    Whole-exome sequencing has been incredibly successful in identifying causal genetic variants and has revealed a number of novel genes associated with blood and other diseases. One limitation of this approach is that it overlooks mutations in noncoding regulatory elements. Furthermore, the mechanisms by which mutations in transcriptionalcis-regulatory elements result in disease remain poorly understood. Here we used CRISPR/Cas9 genome editing to interrogate three such elements harboring mutations in human erythroid disorders, which in all cases are predicted to disrupt a canonical binding motif for the hematopoietic transcription factor GATA1. Deletions of as few as two to four nucleotides resulted in a substantial decrease (>80%) in target gene expression. Isolated deletions of the canonical GATA1 binding motif completely abrogated binding of the cofactor TAL1, which binds to a separate motif. Having verified the functionality of these three GATA1 motifs, we demonstrate strong evolutionary conservation of GATA1 motifs in regulatory elements proximal to other genes implicated in erythroid disorders, and show that targeted disruption of such elements results in altered gene expression. By modeling transcription factor binding patterns, we show that multiple transcription factors are associated with erythroid gene expression, and have created predictive maps modeling putative disruptions of their binding sites at key regulatory elements. Our study provides insight into GATA1 transcriptional activity and may prove a useful resource for investigating the pathogenicity of noncoding variants in human erythroid disorders. PMID:27044088

  8. Insight into GATA1 transcriptional activity through interrogation of cis elements disrupted in human erythroid disorders

    PubMed Central

    Wakabayashi, Aoi; Ulirsch, Jacob C.; Ludwig, Leif S.; Fiorini, Claudia; Yasuda, Makiko; Choudhuri, Avik; McDonel, Patrick; Zon, Leonard I.; Sankaran, Vijay G.

    2016-01-01

    Whole-exome sequencing has been incredibly successful in identifying causal genetic variants and has revealed a number of novel genes associated with blood and other diseases. One limitation of this approach is that it overlooks mutations in noncoding regulatory elements. Furthermore, the mechanisms by which mutations in transcriptional cis-regulatory elements result in disease remain poorly understood. Here we used CRISPR/Cas9 genome editing to interrogate three such elements harboring mutations in human erythroid disorders, which in all cases are predicted to disrupt a canonical binding motif for the hematopoietic transcription factor GATA1. Deletions of as few as two to four nucleotides resulted in a substantial decrease (>80%) in target gene expression. Isolated deletions of the canonical GATA1 binding motif completely abrogated binding of the cofactor TAL1, which binds to a separate motif. Having verified the functionality of these three GATA1 motifs, we demonstrate strong evolutionary conservation of GATA1 motifs in regulatory elements proximal to other genes implicated in erythroid disorders, and show that targeted disruption of such elements results in altered gene expression. By modeling transcription factor binding patterns, we show that multiple transcription factors are associated with erythroid gene expression, and have created predictive maps modeling putative disruptions of their binding sites at key regulatory elements. Our study provides insight into GATA1 transcriptional activity and may prove a useful resource for investigating the pathogenicity of noncoding variants in human erythroid disorders. PMID:27044088

  9. Rare-earth elements in Egyptian granite by instrumental neutron activation analysis.

    PubMed

    El-Taher, A

    2007-04-01

    The mobilization of rare-earth elements (REEs) in the environment requires monitoring of these elements in environmental matrices, in which they are mainly present at trace levels. The similarity in REEs chemical behavior makes the separate determination of each element by chemical methods difficult; instrumental neutron activation analysis (INAA), based on nuclear properties of the elements to be determined, is a method of choice in trace analysis of REEs and related elements. Therefore, INAA was applied as a sensitive nondestructive analytical tool for the determination of REEs to find out what information could be obtained about the REEs of some Egyptian granite collected from four locations in Aswan area in south Egypt as follows wadi El-Allaqi, El-Shelal, Gabel Ibrahim Pasha and from Sehyel Island and to estimate the accuracy, reproducibility and detection limit of NAA method in case of the given samples. The samples were properly prepared together with standards and simultaneously irradiated in a neutron flux of 7 x 10(11)n/cm(2)s in the TRIGA Mainz research reactor facilities. The following elements have been determined: La, Ce, Nd, Sm, Eu, Yb and Lu. The gamma spectra was collected by HPGe detector and the analysis was done by means of computerized multichannel analyzer. The X-ray fluorescence (XRF) was also used. PMID:17208446

  10. ICE Afe 1, an actively excising genetic element from the biomining bacterium Acidithiobacillus ferrooxidans.

    PubMed

    Bustamante, Paula; Covarrubias, Paulo C; Levicán, Gloria; Katz, Assaf; Tapia, Pablo; Holmes, David; Quatrini, Raquel; Orellana, Omar

    2012-01-01

    Integrative conjugative elements (ICEs) are self-transferred mobile genetic elements that contribute to horizontal gene transfer. An ICE (ICEAfe1) was identified in the genome of Acidithiobacillus ferrooxidans ATCC 23270. Excision of the element and expression of relevant genes under normal and DNA-damaging growth conditions was analyzed. Bioinformatic tools and DNA amplification methods were used to identify and to assess the excision and expression of genes related to the mobility of the element. Both basal and mitomycin C-inducible excision as well as expression and induction of the genes for integration/excision are demonstrated, suggesting that ICEAfe1 is an actively excising SOS-regulated mobile genetic element. The presence of a complete set of genes encoding self-transfer functions that are induced in response to DNA damage caused by mitomycin C additionally suggests that this element is capable of conjugative transfer to suitable recipient strains. Transfer of ICEAfe1 may provide selective advantages to other acidophiles in this ecological niche through dissemination of gene clusters expressing transfer RNAs, CRISPRs, and exopolysaccharide biosynthesis enzymes, probably by modification of translation efficiency, resistance to bacteriophage infection and biofilm formation, respectively. These data open novel avenues of research on conjugative transformation of biotechnologically relevant microorganisms recalcitrant to genetic manipulation. PMID:23486178

  11. Atmospheric Deposition of Trace Elements in Ombrotrophic Peat as a Result of Anthropic Activities

    NASA Astrophysics Data System (ADS)

    Fabio Lourençato, Lucio; Cabral Teixeira, Daniel; Vieira Silva-Filho, Emmanoel

    2014-05-01

    Ombrotrophic peat can be defined as a soil rich in organic matter, formed from the partial decomposition of vegetable organic material in a humid and anoxic environment, where the accumulation of material is necessarily faster than the decomposition. From the physical-chemical point of view, it is a porous and highly polar material with high adsorption capacity and cation exchange. The high ability of trace elements to undergo complexation by humic substances happens due to the presence of large amounts of oxygenated functional groups in these substances. Since the beginning of industrialization human activities have scattered a large amount of trace elements in the environment. Soil contamination by atmospheric deposition can be expressed as a sum of site contamination by past/present human activities and atmospheric long-range transport of trace elements. Ombrotrophic peat records can provide valuable information about the entries of trace metals into the atmosphere and that are subsequently deposited on the soil. These trace elements are toxic, non-biodegradable and accumulate in the food chain, even in relatively low quantities. Thus studies on the increase of trace elements in the environment due to human activities are necessary, particularly in the southern hemisphere, where these data are scarce. The aims of this study is to evaluate the concentrations of mercury in ombrotrophic peat altomontanas coming from atmospheric deposition. The study is conducted in the Itatiaia National Park, Brazilian conservation unit, situated between the southeastern state of Rio de Janeiro, São Paulo and Minas Gerais. An ombrotrophic peat core is being sampled in altitude (1980m), to measure the trace elements concentrations of this material. As it is conservation area, the trace elements found in the samples is mainly from atmospheric deposition, since in Brazil don't exist significant lithology of trace elements. The samples are characterized by organic matter content which

  12. Infected Donor Biomass and Active Feeding Increase Waterborne Transmission of Ichthyophonus sp. to Rainbow Trout Sentinels.

    PubMed

    LaPatra, S E; Kocan, R M

    2016-06-01

    The precise nature of Ichthyophonus sp. transmission among wild fishes has eluded description for over a century. Transmission among piscivores is direct, via ingestion of infected prey, but there is also evidence for waterborne transmission between infected and uninfected individuals. Transmission among planktivores is believed to be via a waterborne infectious cell, but definitive proof of this mechanism has not been forthcoming. To explore possible mechanisms of transmission we used Rainbow Trout Oncorhynchus mykiss as a model system and examined the consequence of housing infected donor fish with uninfected (sentinel) fish, without physical contact. We examined two variables linked to transmission: (1) feeding and nonfeeding sentinel fish, and (2) biomass of infected donor fish. Specific-pathogen free sentinel trout were placed in fine-mesh baskets suspended in tanks containing varying numbers of larger Ichthyophonus-infected donor fish and held for 10 weeks, during which time they were examined by in vitro explant culture for the presence of Ichthyophonus. Treatment groups consisted of fed and unfed sentinels housed with infected donors of increasing biomass. After 10 weeks infection prevalence in fed sentinels was significantly higher than in unfed sentinels, and Ichthyophonus was detected earlier in fed fish than in unfed fish. There was no correlation between infection prevalence and donor biomass in fed sentinels, but there was a strong correlation between infection prevalence and increasing donor biomass in unfed sentinels. These data suggest that Ichthyophonus is maintained in wild fish populations by two distinct mechanisms: (1) waterborne infectious cells ingested directly from the water by planktivores, and (2) both infected prey and waterborne infectious cells ingested by piscivores. Received November 13, 2015; accepted February 13, 2016. PMID:27195430

  13. A finite element method for active vibration control of uncertain structures

    NASA Astrophysics Data System (ADS)

    Morales, A. L.; Rongong, J. A.; Sims, N. D.

    2012-10-01

    This work introduces a fuzzy design method using the finite element procedure to simulate and analyze active vibration control of structures subjected to uncertain parameters. The purpose of this work is to provide a tool for studying the influence of uncertainty propagation on both stability and performance of a vibration control system, whilst avoiding the need for computationally expensive probabilistic methods or complex robust control techniques. The proposed procedure applies a general and efficient strategy for computing fuzzy results to a sequence of finite element calculations. Finally, the applicability of the methodology is illustrated through some realistic case studies related to structural control where spillover instability may arise.

  14. Nuclear activation method and apparatus for detecting and quantifying earth elements

    SciTech Connect

    Carroll, J.F.

    1993-08-17

    A method is described for characterizing at least one activated element in an earth formation surrounding a borehole, comprising the steps of: (a) displacing in said borehole a sonde comprising a neutron source and at least two gamma ray detectors longitudinally spaced from said source, while irradiating said formation with neutrons of sufficient energy to interact with said element according to the activation reaction; (b) detecting and counting at each detector the gamma rays resulting from the activation of atoms of said element; (c) determining, at each depth, the number of gamma ray counts detected during the time period defined by the time instants when respectively said source and said detectors pass that depth, said determination of gamma ray counts being made for each detector at each depth; (d) establishing a relationship, for each depth, between the counts from the respective detectors for that depth and the corresponding time instants when the corresponding detector passes that depth; and (e) deriving from said relationship at least one characteristic of said element.

  15. Hop, an active Mutator-like element in the genome of the fungus Fusarium oxysporum.

    PubMed

    Chalvet, Fabienne; Grimaldi, Christine; Kaper, Fiona; Langin, Thierry; Daboussi, Marie-Josée

    2003-08-01

    A new type of active DNA transposon has been identified in the genome of Fusarium oxysporum by its transposition into the niaD target gene. Two insertions within the final exon, in opposite orientations at the same nucleotide site, have been characterized. These elements, called Hop, are 3,299 bp long, with perfect terminal inverted repeats (TIRs) of 99 bp. The sequencing of genomic copies reveals a 9-bp target site duplication and no apparent sequence specificity at the insertion sites. The sequencing of a cDNA indicates that Hop does not contain an intron and encodes a putative transposase of 836 amino acids. The structural features (length, TIRs size, and 9-bp duplication), together with the presence of conserved domains in the transposase, strongly suggest that Hop is a Mutator-like element (MULE). Hop is thus the first active member of this family found beyond plants. The high rate of excision observed indicates that Hop is very active and thus represents a promising efficient tagging system for the isolation of fungal genes. The distribution of Hop elements within the Fusarium genus revealed that they are present in different species, suggesting that related elements could be present in other fungal genomes. In fact, Hop-related sequences have been identified in the survey of the entire genome sequence of three other ascomycetes, Magnaporthe grisea, Neurospora crassa, and Aspergillus fumigatus. PMID:12777515

  16. Transposable elements become active and mobile in the genomes of aging mammalian somatic tissues.

    PubMed

    De Cecco, Marco; Criscione, Steven W; Peterson, Abigail L; Neretti, Nicola; Sedivy, John M; Kreiling, Jill A

    2013-12-01

    Transposable elements (TEs) were discovered by Barbara McClintock in maize and have since been found to be ubiquitous in all living organisms. Transposition is mutagenic and organisms have evolved mechanisms to repress the activity of their endogenous TEs. Transposition in somatic cells is very low, but recent evidence suggests that it may be derepressed in some cases, such as cancer development. We have found that during normal aging several families of retrotransposable elements (RTEs) start being transcribed in mouse tissues. In advanced age the expression culminates in active transposition. These processes are counteracted by calorie restriction (CR), an intervention that slows down aging. Retrotransposition is also activated in age-associated, naturally occurring cancers in the mouse. We suggest that somatic retrotransposition is a hitherto unappreciated aging process. Mobilization of RTEs is likely to be an important contributor to the progressive dysfunction of aging cells. PMID:24323947

  17. Active muscle response using feedback control of a finite element human arm model.

    PubMed

    Östh, Jonas; Brolin, Karin; Happee, Riender

    2012-01-01

    Mathematical human body models (HBMs) are important research tools that are used to study the human response in car crash situations. Development of automotive safety systems requires the implementation of active muscle response in HBM, as novel safety systems also interact with vehicle occupants in the pre-crash phase. In this study, active muscle response was implemented using feedback control of a nonlinear muscle model in the right upper extremity of a finite element (FE) HBM. Hill-type line muscle elements were added, and the active and passive properties were assessed. Volunteer tests with low impact loading resulting in elbow flexion motions were performed. Simulations of posture maintenance in a gravity field and the volunteer tests were successfully conducted. It was concluded that feedback control of a nonlinear musculoskeletal model can be used to obtain posture maintenance and human-like reflexive responses in an FE HBM. PMID:21294008

  18. Controlled trial of polymeric versus elemental diet in treatment of active Crohn's disease.

    PubMed

    Giaffer, M H; North, G; Holdsworth, C D

    1990-04-01

    30 patients with active Crohn's disease, mean Crohn's Disease Activity Index 301 (SE 32), who would otherwise have been treated with steroids, were randomised to receive for 4 weeks either an elemental diet ('Vivonex') (n = 16) or a polymeric diet ('Fortison') (n = 14). Assessment on days 10 and 28 showed that clinical remission occurred in 5 (36%) of the 14 patients on fortison compared with 12 (75%) of the 16 patients assigned to vivonex. The difference in remission rate was significant (p less than 0.03). Dietary treatment resulted in little change in the nutritional state and various laboratory indices of activity over a 4 week period despite clinical improvement. Polymeric diets do not seem to offer an effective therapeutic alternative to elemental diets in patients with acute exacerbations of Crohn's disease. PMID:1969560

  19. Rotorcraft transmissions

    NASA Technical Reports Server (NTRS)

    Coy, John J.

    1990-01-01

    Highlighted here is that portion of the Lewis Research Center's helicopter propulsion systems program that deals with drive train technology and the related mechanical components. The major goals of the program are to increase life, reliability, and maintainability, to reduce weight, noise, and vibration, and to maintain the relatively high mechanical efficiency of the gear train. The current activity emphasizes noise reduction technology and analytical code development, followed by experimental verification. Selected significant advances in technology for transmissions are reviewed, including advanced configurations and new analytical tools. Finally, the plan for transmission research in the future is presented.

  20. Point mutations in the S protein connect the sialic acid binding activity with the enteropathogenicity of transmissible gastroenteritis coronavirus.

    PubMed Central

    Krempl, C; Schultze, B; Laude, H; Herrler, G

    1997-01-01

    Enteropathogenic transmissible gastroenteritis virus (TGEV), a porcine coronavirus, is able to agglutinate erythrocytes because of sialic acid binding activity. Competitive inhibitors that may mask the sialic acid binding activity can be inactivated by sialidase treatment of virions. Here, we show that TGEV virions with efficient hemagglutinating activity were also obtained when cells were treated with sialidase prior to infection. This method was used to analyze TGEV mutants for hemagglutinating activity. Recently, mutants with strongly reduced enteropathogenicity that have point mutations or a deletion of four amino acids within residues 145 to 155 of the S protein have been described. Here, we show that in addition to their reduced pathogenicity, these mutants also have lost hemagglutinating activity. These results connect sialic acid binding activity with the enteropathogenicity of TGEV. PMID:9060696

  1. A Tale of Transmission: Aeromonas veronii Activity within Leech-Exuded Mucus.

    PubMed

    Ott, Brittany M; Dacks, Andrew M; Ryan, Kenneth J; Rio, Rita V M

    2016-05-01

    Transmission, critical to the establishment and persistence of host-associated microbiotas, also exposes symbionts to new environmental conditions. With horizontal transmission, these different conditions represent major lifestyle shifts. Yet genome-wide analyses of how microbes adjust their transcriptomes toward these dramatic shifts remain understudied. Here, we provide a comprehensive and comparative analysis of the global transcriptional profiles of a symbiont as it shifts between lifestyles during transmission. The gammaproteobacteriumAeromonas veroniiis transmitted from the gut of the medicinal leech to other hosts via host mucosal castings, yetA. veroniican also transition from mucosal habitancy to a free-living lifestyle. These three lifestyles are characterized by distinct physiological constraints and consequently lifestyle-specific changes in the expression of stress-response genes. Mucus-boundA. veroniihad the greatest expression in terms of both the number of loci and levels of transcription of stress-response mechanisms. However, these bacteria are still capable of proliferating within the mucus, suggesting the availability of nutrients within this environment. We found thatA. veroniialters transcription of loci in a synthetic pathway that obtains and incorporatesN-acetylglucosamine (NAG; a major component of mucus) into the bacterial cell wall, enabling proliferation. Our results demonstrate that symbionts undergo dramatic local adaptation, demonstrated by widespread transcriptional changes, throughout the process of transmission that allows them to thrive while they encounter new environments which further shape their ecology and evolution. PMID:26896136

  2. Neutron activation analysis of major, minor, and trace elements in marine sediments

    SciTech Connect

    Stone, S.F.; Zeisler, R.; Koster, B.J.

    1988-01-01

    Neutron activation analysis (NAA) techniques are well established in the multielement assay of geological materials. Similarly, applications of NAA to the analysis of marine sediments have been described. The different emphasis on elemental composition in studying and monitoring the health of the environment, however, presents a new challenge to the analyst. To investigate as many elements as possible, previous multielement procedures need to be reevaluated and modified. In this work, the authors have utilized the NAA steps of a recently developed sequential analysis procedure that obtained concentrations for 45 biological and pollutant elements in marine bivalves. This procedure, with modification, was applied to samples of marine sediments collected for the National Oceanic and Atmospheric Administration (NOAA) National Status and Trends (NS T) specimen banking program.

  3. Elemental characterization of the Avogadro silicon crystal WASO 04 by neutron activation analysis

    NASA Astrophysics Data System (ADS)

    D'Agostino, G.; Bergamaschi, L.; Giordani, L.; Mana, G.; Massa, E.; Oddone, M.

    2012-12-01

    Impurity measurements of the 28Si crystal used for the determination of the Avogadro constant are essential to prevent biased results or underestimated uncertainties. A review of the existing data confirmed the high purity of silicon with respect to a large number of elements. In order to obtain direct evidence of purity, we developed a relative analytical method based on neutron activation. As a preliminary test, this method was applied to a sample of the Avogadro natural silicon crystal WASO 04. The investigation concerned 29 elements. The mass fraction of Au was quantified to be (1.03 ± 0.18) × 10-12. For the remaining 28 elements, the mass fractions were below the detection limits, which ranged between 1 × 10-12 and 1 × 10-5.

  4. Antiretroviral Medication Adherence and Amplified HIV Transmission Risk Among Sexually Active HIV-Infected Individuals in Three Diverse International Settings.

    PubMed

    Magidson, Jessica F; Li, Xin; Mimiaga, Matthew J; Moore, Ayana T; Srithanaviboonchai, Kriengkrai; Friedman, Ruth Khalili; Limbada, Mohammad; Hughes, James P; Cummings, Vanessa; Gaydos, Charlotte A; Elharrar, Vanessa; Celentano, David; Mayer, Kenneth H; Safren, Steven A

    2016-04-01

    Successful biomedical prevention/treatment-as-prevention (TasP) requires identifying individuals at greatest risk for transmitting HIV, including those with antiretroviral therapy (ART) nonadherence and/or 'amplified HIV transmission risk,' defined as condomless sex with HIV-uninfected/unknown-status partners when infectious (i.e., with detectable viremia or STI diagnosis according to Swiss criteria for infectiousness). This study recruited sexually-active, HIV-infected patients in Brazil, Thailand, and Zambia to examine correlates of ART nonadherence and 'amplified HIV transmission risk'. Lower alcohol use (OR = .71, p < .01) and higher health-related quality of life (OR = 1.10, p < .01) were associated with greater odds of ART adherence over and above region. Of those with viral load data available (in Brazil and Thailand only), 40 % met Swiss criteria for infectiousness, and 29 % had 'amplified HIV transmission risk.' MSM had almost three-fold (OR = 2.89, p < .001) increased odds of 'amplified HIV transmission risk' (vs. heterosexual men) over and above region. TasP efforts should consider psychosocial and contextual needs, particularly among MSM with detectable viremia. PMID:26246068

  5. 1550 nm VCSEL-based 0.48 Tb/s transmission scheme employing PAM-4 and WDM for active optical cables

    NASA Astrophysics Data System (ADS)

    Markou, S.; Dris, S.; Kalavrouziotis, D.; Avramopoulos, H.; Pleros, N.; Tsiokos, Dimitris M.

    2014-05-01

    With this paper we investigate the system-level performance of VCSELs, parameterized with true experimental LI-VI data and dynamic characteristics of state-of-the-art VCSELs with 3 dB modulation bandwidth at 15 GHz, and propose their deployment as high-speed multi-level optical sources in a mid-range active optical cable (AOC) model for performance prediction of a rack-to-rack interconnection. The AOC architecture combines a 6-element 1550 nm VCSEL array, each directly modulated with 40 Gbaud PAM-4 data, with a wavelength division multiplexer (WDM), in order to implement a parallel link with aggregate traffic of 0.48 Tb/s. Transmission reach exceeded 300 m by deploying a two-tap feed forward equalizer filter at the electrical VCSEL driver. Bit Error Rate (BER) measurements and analysis were carried out in MATLAB. In practice, the thermal behavior and basic operational characteristics of the VCSELs fabricated by the Technische Universität München (TUM) were used to study the thermal performance and operational range of the complete AOC model. The VCSELs were initially operated at 20°C and BER measurements showed power penalties of 1.7 dB and 3.5 dB at 300 m and 500 m of transmission distance respectively for all 6 data channels. System performance was also investigated for elevated operating temperatures of the VCSEL module and the additional system degradation and BER penalties introduced by operation at 50°C and 65°C were also investigated for transmission distances of 300 m and 500 m.

  6. Peak-valley-peak pattern of histone modifications delineates active regulatory elements and their directionality.

    PubMed

    Pundhir, Sachin; Bagger, Frederik O; Lauridsen, Felicia B; Rapin, Nicolas; Porse, Bo T

    2016-05-19

    Formation of nucleosome free region (NFR) accompanied by specific histone modifications at flanking nucleosomes is an important prerequisite for enhancer and promoter activity. Due to this process, active regulatory elements often exhibit a distinct shape of histone signal in the form of a peak-valley-peak (PVP) pattern. However, different features of PVP patterns and their robustness in predicting active regulatory elements have never been systematically analyzed. Here, we present PARE, a novel computational method that systematically analyzes the H3K4me1 or H3K4me3 PVP patterns to predict NFRs. We show that NFRs predicted by H3K4me1 and me3 patterns are associated with active enhancers and promoters, respectively. Furthermore, asymmetry in the height of peaks flanking the central valley can predict the directionality of stable transcription at promoters. Using PARE on ChIP-seq histone modifications from four ENCODE cell lines and four hematopoietic differentiation stages, we identified several enhancers whose regulatory activity is stage specific and correlates positively with the expression of proximal genes in a particular stage. In conclusion, our results demonstrate that PVP patterns delineate both the histone modification landscape and the transcriptional activities governed by active enhancers and promoters, and therefore can be used for their prediction. PARE is freely available at http://servers.binf.ku.dk/pare. PMID:27095194

  7. Peak-valley-peak pattern of histone modifications delineates active regulatory elements and their directionality

    PubMed Central

    Pundhir, Sachin; Bagger, Frederik O.; Lauridsen, Felicia B.; Rapin, Nicolas; Porse, Bo T.

    2016-01-01

    Formation of nucleosome free region (NFR) accompanied by specific histone modifications at flanking nucleosomes is an important prerequisite for enhancer and promoter activity. Due to this process, active regulatory elements often exhibit a distinct shape of histone signal in the form of a peak-valley-peak (PVP) pattern. However, different features of PVP patterns and their robustness in predicting active regulatory elements have never been systematically analyzed. Here, we present PARE, a novel computational method that systematically analyzes the H3K4me1 or H3K4me3 PVP patterns to predict NFRs. We show that NFRs predicted by H3K4me1 and me3 patterns are associated with active enhancers and promoters, respectively. Furthermore, asymmetry in the height of peaks flanking the central valley can predict the directionality of stable transcription at promoters. Using PARE on ChIP-seq histone modifications from four ENCODE cell lines and four hematopoietic differentiation stages, we identified several enhancers whose regulatory activity is stage specific and correlates positively with the expression of proximal genes in a particular stage. In conclusion, our results demonstrate that PVP patterns delineate both the histone modification landscape and the transcriptional activities governed by active enhancers and promoters, and therefore can be used for their prediction. PARE is freely available at http://servers.binf.ku.dk/pare. PMID:27095194

  8. The Holozoan Capsaspora owczarzaki Possesses a Diverse Complement of Active Transposable Element Families

    PubMed Central

    Carr, Martin; Suga, Hiroshi

    2014-01-01

    Capsaspora owczarzaki, a protistan symbiont of the pulmonate snail Biomphalaria glabrata, is the centre of much interest in evolutionary biology due to its close relationship to Metazoa. The whole genome sequence of this protist has revealed new insights into the ancestral genome composition of Metazoa, in particular with regard to gene families involved in the evolution of multicellularity. The draft genome revealed the presence of 23 families of transposable element, made up from DNA transposon as well as long terminal repeat (LTR) and non-LTR retrotransposon families. The phylogenetic analyses presented here show that all of the transposable elements identified in the C. owczarzaki genome have orthologous families in Metazoa, indicating that the ancestral metazoan also had a rich diversity of elements. Molecular evolutionary analyses also show that the majority of families has recently been active within the Capsaspora genome. One family now appears to be inactive and a further five families show no evidence of current transposition. Most individual element copies are evolutionarily young; however, a small proportion of inserts appear to have persisted for longer in the genome. The families present in the genome show contrasting population histories and appear to be in different stages of their life cycles. Transcriptome data have been analyzed from multiple stages in the C. owczarzaki life cycle. Expression levels vary greatly both between families and between different stages of the life cycle, suggesting an unexpectedly complex level of transposable element regulation in a single celled organism. PMID:24696401

  9. Optimization of high temperature sulfur impregnation on activated carbon for permanent sequestration of elemental mercury vapors

    SciTech Connect

    Liu, W.; Vidic, R.D.; Brown, T.D.

    2000-02-01

    Following previous success with the use of activated carbon impregnated with sulfur at elevated temperatures for elemental mercury control, possible improvements in the impregnation procedure were evaluated in this study. Adsorbents prepared by thoroughly mixing sulfur and activated carbon in the furnace at the initial sulfur-to-carbon ratio (SCR) ranging from 4:1 to 1:2 showed similar adsorptive behavior in a fixed-bed system. Maintaining a stagnant inert atmosphere during the impregnation process improves sulfur deposition resulting in the enhanced dynamic capacity of the adsorbent when compared to other sulfur impregnated carbons. The fate of spent adsorbents was assessed using a toxicity characteristics leaching procedure (TCLP). Although mercury concentration in all leachates was below the TCLP limit, virgin activated carbon lost a significant fraction of the adsorbed elemental mercury during storage, while no loss was observed for sulfur-impregnated carbons. This finding suggests that virgin activated carbon may not be appropriate adsorbent for permanent sequestration of anthropogenic elemental mercury emissions.

  10. Amidase activity in soils. IV. Effects of trace elements and pesticides

    SciTech Connect

    Frankenberger, W.T., Jr.; Tabatabai, M.A.

    1981-11-01

    Amidase was recently detected in soils, and this study was carried out to assess the effects of 21 trace elements, 12 herbicides, 2 fungicides, and 2 insecticides on the activity of this enzyme. Results showed that most of the trace elements and pesticides studied inhibited amidase activity in soils. The degree of inhibition varied among the soils used. When the trace elements were compared by using 5 ..mu..mol/g of soil, the average inhibition of amidase in three soils showed that Ag(I), Hg(I), As(III), and Se(IV) were the most effective inhibitors, but only Ag(I) and As(III) showed average inhibition > 50%. The least effective inhibitors (average inhibition < 3%) included Cu(I), Ba(II), Cu(II), Fe(II), Ni(II), Al(III), Fe(III), Ti(IV), V(IV), As(V), Mo(VI), and W(VI). Other elements that inhibited amidase activity in soils were Cd(II), Co(II), Mn(II), Pb(II), Sn(II), Zn(II), B(III), and Cr(III). Enzyme kinetic studies showed that As(III) was a competitive inhibitor of amidase, whereas Ag(I), Hg(II), and Se(IV) were noncompetitive inhibitors. When the pesticides studied were compared by using 10 ..mu..g of active ingredient per gram of soil, the average inhibition of amidase in three soils ranged from 2% with dinitroamine, EPTC plus R-25788, and captan to 10% with butylate. Other pesticides that inhibited amidase activity in soils were atrazine, naptalam, chloramben, dicamba, cyanazine, 2,4-D, alachlor, paraquat, trifluralin, maneb, diazinon, and malathion. The inhibition of amidase by diazinon, alachlor, and butylate followed noncompetitive kinetics.

  11. Increased prevalence of carbapenem resistant Enterobacteriaceae in hospital setting due to cross-species transmission of the blaNDM-1 element and clonal spread of progenitor resistant strains

    PubMed Central

    Wang, Xuan; Chen, Gongxiang; Wu, Xiaoyan; Wang, Liangping; Cai, Jiachang; Chan, Edward W.; Chen, Sheng; Zhang, Rong

    2015-01-01

    This study investigated the transmission characteristics of carbapenem-resistant Enterobacteriaceae (CRE) strains collected from a hospital setting in China, in which consistent emergence of CRE strains were observable during the period of May 2013 to February 2014. Among the 45 CRE isolates tested, 21 (47%) strains were found to harbor the blaNDM-1 element, and the rest of 24 CRE strains were all positive for blaKPC-2. The 21 blaNDM-1—borne strains were found to comprise multiple Enterobacteriaceae species including nine Enterobacter cloacae, three Escherichia coli, three Citrobacter freundii, two Klebsiella pneumoniae, two Klebsiella oxytoca, and two Morganella morganii strains, indicating that cross-species transmission of blaNDM-1 is a common event. Genetic analyses by PFGE and MLST showed that, with the exception of E. coli and E. cloacae, strains belonging to the same species were often genetically unrelated. In addition to blaNDM-1, several CRE strains were also found to harbor the blaKPC-2, blaVIM-1, and blaIMP-4 elements. Conjugations experiments confirmed that the majority of carbapenem resistance determinants were transferable. Taken together, our findings suggest that transmission of mobile resistance elements among members of Enterobacteriaceae and clonal spread of CRE strains may contribute synergistically to a rapid increase in the population of CRE in clinical settings, prompting a need to implement more rigorous infection control measures to arrest such vicious transmission cycle in CRE-prevalent areas. PMID:26136735

  12. Transmit B1 Field Correction at 7T using Actively Tuned Coupled Inner Elements

    PubMed Central

    Merkle, Hellmut; Murphy-Boesch, Joseph; van Gelderen, Peter; Wang, Shumin; Li, Tie-Qiang; Koretsky, Alan P.; Duyn, Josef H.

    2011-01-01

    When volume coils are used for 1H imaging of the human head at 7T, wavelength effects in tissue cause intensity variations that are typically brighter at the center of the head and darker in the periphery. Much of this image non-uniformity can be attributed to variation in the effective transmit B1 field, which falls by about 50% to the left and right of center at mid-elevation in the brain. Because most of this B1 loss occurs in the periphery of the brain, we have explored use of actively controlled, off-resonant loop elements to locally enhance the transmit B1 field in these regions. When tuned to frequencies above the NMR frequency, these elements provide strong local enhancement of the B1 field of the transmit coil. Because they are tuned off-resonance, some volume coil detuning results, but resistive loading of the coil mode remains dominated by the sample. By digitally controlling their frequency offsets, the field enhancement of each inner element can be placed under active control. Using an array of eight, digitally-controlled elements placed around a custom-built head phantom, we demonstrate the feasibility of improving the B1 homogeneity of a transmit/receive volume coil without the need for multiple RF transmit channels. PMID:21437974

  13. Micromechanical analysis and finite element modeling of electromechanical properties of active piezoelectric structural fiber (PSF) composites

    NASA Astrophysics Data System (ADS)

    Dai, Qingli; Ng, Kenny

    2013-04-01

    This paper presents the combined micromechanics analysis and finite element modeling of the electromechanical properties of piezoelectric structural fiber (PSF) composites. The active piezoelectric materials are widely used due to their high stiffness, voltage-dependent actuation capability, and broadband electro-mechanical interactions. However, the fragile nature of piezoceramics limits their sensing and actuating applications. In this study, the active PSF composites were made by deploying the longitudinally poled PSFs into a polymer matrix. The PSF itself consists a silicon carbide (SiC) or carbon core fiber as reinforcement to the fragile piezoceramic shell. To predict the electromechanical properties of PSF composites, the micromechanics analysis was firstly conducted with the dilute approximation model and the Mori-Tanaka approach. The extended Rule of Mixtures was also applied to accurately predict the transverse properties by considering the effects of microstructure including inclusion sizes and geometries. The piezoelectric finite element (FE) modeling was developed with the ABAQUS software to predict the detailed mechanical and electrical field distribution within a representative volume element (RVE) of PSF composites. The simulated energy or deformation under imposed specific boundary conditions was used to calculate each individual property with constitutive laws. The comparison between micromechanical analysis and finite element modeling indicates the combination of the dilute approximation model, the Mori-Tanaka approach and the extended Rule of Mixtures can favorably predict the electromechanical properties of three-phase PSF composites.

  14. Elemental abundances in atmospheres of cool dwarfs with solar-like activity

    NASA Astrophysics Data System (ADS)

    Antipova, L. I.; Boyarchuk, A. A.

    2016-01-01

    The elemental abundances in the atmosphere of the red dwarf HD 32147, which belongs to the HR 1614 moving groups, are analyzed. The atmospheric parameters determined from spectroscopic data (the condition of equal abundances for neutral and ionized atoms of a given element) differ considerably from those derived from photometry and parallax data. The abundances of several elements are also anomalous, with the anomaly increasing with decreasing ionization potential. It is concluded that this star is a red dwarf displaying solar-like activity; i.e., having dark (cool) spots on its surface, which may sometimes be considerable in size. Modeling synthetic spectra of stars with cool spots on their surfaces, with the spectral lines consisting of two components formed in media with different temperatures, indicate that the spectroscopic atmospheric parameters derived in such cases are incorrect; this can also explain the observed dependence of the elemental abundances on the corresponding ionization potentials. This leads to the conclusion thatHD32147 is indeed a star with solar-like activity. Several other such stars considered as examples display the same anomalies as those of HD 32147. These modeling results are also valid for Ap and Am stars, and are able to explain short-wavelength observations of the Sun and some stars (the FIP effect).

  15. ERV-L Elements: a Family of Endogenous Retrovirus-Like Elements Active throughout the Evolution of Mammals

    PubMed Central

    Bénit, Laurence; Lallemand, Jean-Baptiste; Casella, Jean-François; Philippe, Hervé; Heidmann, Thierry

    1999-01-01

    We have previously identified in the human genome a family of 200 endogenous retrovirus-like elements, the HERV-L elements, disclosing similarities with the foamy retroviruses and which might be the evolutionary intermediate between classical intracellular retrotransposons and infectious retroviruses. Southern blot analysis of a large series of mammalian genomic DNAs shows that HERV-L-related elements—so-called ERV-L—are present among all placental mammals, suggesting that ERV-L elements were already present at least 70 million years ago. Most species exhibit a low copy number of ERV-L elements (from 10 to 30), while simians (not prosimians) and mice (not rats) have been subjected to bursts resulting in increases in the number of copies up to 200. The burst of copy number in primates can be dated to shortly after the prosimian and simian branchpoint, 45 to 65 million years ago, whereas murine species have been subjected to two much more recent bursts (less than 10 million years ago), occurring after the Mus/Rattus split. We have amplified and sequenced 360-bp ERV-L internal fragments of the highly conserved pol gene from a series of 22 mammalian species. These sequences exhibit high percentages of identity (57 to 99%) with the murine fully coding MuERV-L element. Phylogenetic analyses allowed the establishment of a plausible evolutionary scheme for ERV-L elements, which accounts for the high level of sequence conservation and the widespread dispersion among mammals. PMID:10074184

  16. Active magnetic bearing control loop modeling for a finite element rotordynamics code

    NASA Technical Reports Server (NTRS)

    Genta, Giancarlo; Delprete, Cristiana; Carabelli, Stefano

    1994-01-01

    A mathematical model of an active electromagnetic bearing which includes the actuator, the sensor and the control system is developed and implemented in a specialized finite element code for rotordynamic analysis. The element formulation and its incorporation in the model of the machine are described in detail. A solution procedure, based on a modal approach in which the number of retained modes is controlled by the user, is then shown together with other procedures for computing the steady-state response to both static and unbalance forces. An example of application shows the numerical results obtained on a model of an electric motor suspended on a five active-axis magnetic suspension. The comparison of some of these results with the experimental characteristics of the actual system shows the ability of the present model to predict its performance.

  17. Direct tests of a pixelated microchannel plate as the active element of a shower maximum detector

    DOE PAGESBeta

    Apresyan, A.; Los, S.; Pena, C.; Presutti, F.; Ronzhin, A.; Spiropulu, M.; Xie, S.

    2016-05-07

    One possibility to make a fast and radiation resistant shower maximum detector is to use a secondary emitter as an active element. We report our studies of microchannel plate photomultipliers (MCPs) as the active element of a shower-maximum detector. We present test beam results obtained using Photonis XP85011 to detect secondary particles of an electromagnetic shower. We focus on the use of the multiple pixels on the Photonis MCP in order to find a transverse two-dimensional shower distribution. A spatial resolution of 0.8 mm was obtained with an 8 GeV electron beam. As a result, a method for measuring themore » arrival time resolution for electromagnetic showers is presented, and we show that time resolution better than 40 ps can be achieved.« less

  18. Development of multi-element active aerodynamics for the formula sae car

    NASA Astrophysics Data System (ADS)

    Merkel, James Patrick

    This thesis focuses on the design, development, and implementation of an active aerodynamics system on 2013 Formula SAE car. The aerodynamics package itself consists of five element front and rear wings as well as an under body diffuser. Five element wings produce significant amounts of drag which is a compromise between the cornering ability of the car and the acceleration capability on straights. The active aerodynamics system allows for the wing angle of attack to dynamically change their configuration on track based on sensory data to optimize the wings for any given scenario. The wings are studied using computational fluid dynamics both in their maximum lift configuration as well as a minimum drag configuration. A control system is then developed using an electro mechanical actuation system to articulate the wings between these two states.

  19. Active magnetic bearing control loop modeling for a finite element rotordynamics code

    NASA Astrophysics Data System (ADS)

    Genta, Giancarlo; Delprete, Cristiana; Carabelli, Stefano

    1994-05-01

    A mathematical model of an active electromagnetic bearing which includes the actuator, the sensor and the control system is developed and implemented in a specialized finite element code for rotordynamic analysis. The element formulation and its incorporation in the model of the machine are described in detail. A solution procedure, based on a modal approach in which the number of retained modes is controlled by the user, is then shown together with other procedures for computing the steady-state response to both static and unbalance forces. An example of application shows the numerical results obtained on a model of an electric motor suspended on a five active-axis magnetic suspension. The comparison of some of these results with the experimental characteristics of the actual system shows the ability of the present model to predict its performance.

  20. Direct tests of a pixelated microchannel plate as the active element of a shower maximum detector

    NASA Astrophysics Data System (ADS)

    Apresyan, A.; Los, S.; Pena, C.; Presutti, F.; Ronzhin, A.; Spiropulu, M.; Xie, S.

    2016-08-01

    One possibility to make a fast and radiation resistant shower maximum detector is to use a secondary emitter as an active element. We report our studies of microchannel plate photomultipliers (MCPs) as the active element of a shower-maximum detector. We present test beam results obtained using Photonis XP85011 to detect secondary particles of an electromagnetic shower. We focus on the use of the multiple pixels on the Photonis MCP in order to find a transverse two-dimensional shower distribution. A spatial resolution of 0.8 mm was obtained with an 8 GeV electron beam. A method for measuring the arrival time resolution for electromagnetic showers is presented, and we show that time resolution better than 40 ps can be achieved.

  1. Native Thrombocidin-1 and Unfolded Thrombocidin-1 Exert Antimicrobial Activity via Distinct Structural Elements

    PubMed Central

    Kwakman, Paulus H. S.; Krijgsveld, Jeroen; de Boer, Leonie; Nguyen, Leonard T.; Boszhard, Laura; Vreede, Jocelyne; Dekker, Henk L.; Speijer, Dave; Drijfhout, Jan W.; te Velde, Anje A.; Crielaard, Wim; Vogel, Hans J.; Vandenbroucke-Grauls, Christina M. J. E.; Zaat, Sebastian A. J.

    2011-01-01

    Chemokines (chemotactic cytokines) can have direct antimicrobial activity, which is apparently related to the presence of a distinct positively charged patch on the surface. However, chemokines can retain antimicrobial activity upon linearization despite the loss of their positive patch, thus questioning the importance of this patch for activity. Thrombocidin-1 (TC-1) is a microbicidal protein isolated from human blood platelets. TC-1 only differs from the chemokine NAP-2/CXCL7 by a two-amino acid C-terminal deletion, but this truncation is crucial for antimicrobial activity. We assessed the structure-activity relationship for antimicrobial activity of TC-1. Reduction of the charge of the TC-1-positive patch by replacing lysine 17 with alanine reduced the activity against bacteria and almost abolished activity against the yeast Candida albicans. Conversely, augmentation of the positive patch by increasing charge density or size resulted in a 2–3-fold increased activity against Staphylococcus aureus, Escherichia coli, and Bacillus subtilis but did not substantially affect activity against C. albicans. Reduction of TC-1 resulted in loss of the folded conformation, but this disruption of the positive patch did not affect antimicrobial activity. Using overlapping 15-mer synthetic peptides, we demonstrate peptides corresponding to the N-terminal part of TC-1 to have similar antimicrobial activity as intact TC-1. Although we demonstrate that the positive patch is essential for activity of folded TC-1, unfolded TC-1 retained antimicrobial activity despite the absence of a positive patch. This activity is probably exerted by a linear peptide stretch in the N-terminal part of the molecule. We conclude that intact TC-1 and unfolded TC-1 exert antimicrobial activity via distinct structural elements. PMID:22025617

  2. Thin-disk laser based on an Yb:YAG / YAG composite active element

    NASA Astrophysics Data System (ADS)

    Kuznetsov, I. I.; Mukhin, I. B.; Vadimova, O. L.; Palashov, O. V.

    2015-03-01

    A thin-disk laser module based on an Yb:YAG / YAG composite active element is developed with a small-signal gain of 1.25 and a stored energy of 400 mJ under cw pumping. The gain and thermally induced phase distortions in the module are studied experimentally. Based on this module, a thin-disk laser with an average power of 300 W and a slope efficiency of 42% is designed.

  3. Direct tests of micro channel plates as the active element of a new shower maximum detector

    SciTech Connect

    Ronzhin, A.; Los, S.; Ramberg, E.; Apresyan, A.; Xie, S.; Spiropulu, M.; Kim, H.

    2015-05-22

    We continue the study of micro channel plates (MCP) as the active element of a shower maximum (SM) detector. We present below test beam results obtained with MCPs detecting directly secondary particles of an electromagnetic shower. The MCP efficiency to shower particles is close to 100%. Furthermore, the time resolution obtained for this new type of the SM detector is at the level of 40 ps.

  4. Direct tests of micro channel plates as the active element of a new shower maximum detector

    NASA Astrophysics Data System (ADS)

    Ronzhin, A.; Los, S.; Ramberg, E.; Apresyan, A.; Xie, S.; Spiropulu, M.; Kim, H.

    2015-09-01

    We continue the study of micro channel plates (MCP) as the active element of a shower maximum (SM) detector. We present below test beam results obtained with MCPs detecting directly secondary particles of an electromagnetic shower. The MCP efficiency to shower particles is close to 100%. The time resolution obtained for this new type of the SM detector is at the level of 40 ps.

  5. New Fast Shower Max Detector Based on MCP as an Active Element

    NASA Astrophysics Data System (ADS)

    Ronzhin, A.; Los, S.; Ramberg, E.; Spiropulu, M.; Apresyan, A.; Xie, S.; Kim, H.; Zatserklyaniy, A.

    2015-02-01

    One possibility to make a fast and radiation resistant shower maximum (SM) detector is to use a secondary emitter as an active element. We present below test beam results, obtained with different types of photo detectors based on micro channel plates (MCP) as secondary emitter. The SM time resolution - we obtained for this new type of detector is at the level of 20-30 ps. We estimate that a significant contribution to the detector response originates from secondary emission of the MCP.

  6. Qualitative Elemental Analyses of a Meteorite Sample Found in Turkey by Photo-activation Analysis Method

    NASA Astrophysics Data System (ADS)

    Ertugay, C.; Boztosun, I.; Ozmen, S. F.; Dapo, H.

    2015-04-01

    In this paper, a meteorite sample provided from TÜBITAK National Observatory found in Turkey has been investigated by using a clinical linear accelerator that has endpoint energy of 18 MeV, and a high purity Germanium detector for qualitative elemental analysis within photo-activation analysis method. 21 nuclei ranging from 24Na to 149Nd have been identified in the meteorite sample.

  7. Enhancing immunogenicity and transmission-blocking activity of malaria vaccines by fusing Pfs25 to IMX313 multimerization technology

    PubMed Central

    Li, Yuanyuan; Leneghan, Darren B.; Miura, Kazutoyo; Nikolaeva, Daria; Brian, Iona J.; Dicks, Matthew D. J.; Fyfe, Alex J.; Zakutansky, Sarah E.; de Cassan, Simone; Long, Carole A.; Draper, Simon J.; Hill, Adrian V. S.; Hill, Fergal; Biswas, Sumi

    2016-01-01

    Transmission-blocking vaccines (TBV) target the sexual-stages of the malaria parasite in the mosquito midgut and are widely considered to be an essential tool for malaria elimination. High-titer functional antibodies are required against target antigens to achieve effective transmission-blocking activity. We have fused Pfs25, the leading malaria TBV candidate antigen to IMX313, a molecular adjuvant and expressed it both in ChAd63 and MVA viral vectors and as a secreted protein-nanoparticle. Pfs25-IMX313 expressed from viral vectors or as a protein-nanoparticle is significantly more immunogenic and gives significantly better transmission-reducing activity than monomeric Pfs25. In addition, we demonstrate that the Pfs25-IMX313 protein-nanoparticle leads to a qualitatively improved antibody response in comparison to soluble Pfs25, as well as to significantly higher germinal centre (GC) responses. These results demonstrate that antigen multimerization using IMX313 is a very promising strategy to enhance antibody responses against Pfs25, and that Pfs25-IMX313 is a highly promising TBV candidate vaccine. PMID:26743316

  8. Enhancing immunogenicity and transmission-blocking activity of malaria vaccines by fusing Pfs25 to IMX313 multimerization technology.

    PubMed

    Li, Yuanyuan; Leneghan, Darren B; Miura, Kazutoyo; Nikolaeva, Daria; Brian, Iona J; Dicks, Matthew D J; Fyfe, Alex J; Zakutansky, Sarah E; de Cassan, Simone; Long, Carole A; Draper, Simon J; Hill, Adrian V S; Hill, Fergal; Biswas, Sumi

    2016-01-01

    Transmission-blocking vaccines (TBV) target the sexual-stages of the malaria parasite in the mosquito midgut and are widely considered to be an essential tool for malaria elimination. High-titer functional antibodies are required against target antigens to achieve effective transmission-blocking activity. We have fused Pfs25, the leading malaria TBV candidate antigen to IMX313, a molecular adjuvant and expressed it both in ChAd63 and MVA viral vectors and as a secreted protein-nanoparticle. Pfs25-IMX313 expressed from viral vectors or as a protein-nanoparticle is significantly more immunogenic and gives significantly better transmission-reducing activity than monomeric Pfs25. In addition, we demonstrate that the Pfs25-IMX313 protein-nanoparticle leads to a qualitatively improved antibody response in comparison to soluble Pfs25, as well as to significantly higher germinal centre (GC) responses. These results demonstrate that antigen multimerization using IMX313 is a very promising strategy to enhance antibody responses against Pfs25, and that Pfs25-IMX313 is a highly promising TBV candidate vaccine. PMID:26743316

  9. Electrically small, near-field resonant parasitic (NFRP) antennas augmented with passive and active circuit elements to enhance their functionality

    NASA Astrophysics Data System (ADS)

    Zhu, Ning

    Metamaterials have drawn considerable attention because they can exhibit epsilon-negative (ENG) and/or mu-negative (MNG) properties, which in turn can lead to exotic physical effects that can enable interesting, practical applications. For instance, ENG and MNG properties can be engineered to yield double negative (DNG) properties, such as a negative index of refraction, which leads to flat lenses. Similarly, their extreme versions enable cloaking effects. Inspired by such metamaterial properties, a promising methodology has been developed to design electrically small antennas (ESAs). These ESAs use unit cells of metamaterials as their near-field resonant parasitic (NFRP) elements. This new metamaterial-inspired antenna miniaturization method is extended in this dissertation by augmenting the antenna designs with circuits. A rectifying circuit augmentation is used to achieve electrically small, high efficiency rectenna systems. Rectennas are the enabling components of power harvesting and wireless power transmission systems. Electrically small, integrated rectennas have become popular and in demand for several wireless applications including sensor networks and bio-implanted devices. Four global positioning system (GPS) L1 frequency (1.5754 GHz) rectenna systems were designed, fabricated and measured: three resistor-loaded and one supercapacitor-loaded. The simulated and measured results will be described; good agreement between them was obtained. The NFRP ESAs are also augmented with active, non-Foster elements in order to overcome the physical limits of the impedance bandwidth of passive ESA systems. Unlike conventional active external matching network approaches, the non-Foster components are incorporated directly into the NFRP element of the ESA. Three 300 MHz non-Foster circuit-augmented broadband, ESA systems were demonstrated: an Egyptian axe monopole (EAM) antenna, an Egyptian axe dipole (EAD) antenna, and a protractor antenna. The simulated and measured

  10. Downhole transmission system

    DOEpatents

    Hall, David R.; Fox, Joe

    2008-01-15

    A transmission system in a downhole component comprises a data transmission element in both ends of the downhole component. Each data transmission element houses an electrically conducting coil in a MCEI circular trough. An electrical conductor connects both the transmission elements. The electrical conductor comprises at least three electrically conductive elements insulated from each other. In the preferred embodiment the electrical conductor comprises an electrically conducting outer shield, an electrically conducting inner shield and an electrical conducting core. In some embodiments of the present invention, the electrical conductor comprises an electrically insulating jacket. In other embodiments, the electrical conductor comprises a pair of twisted wires. In some embodiments, the electrical conductor comprises semi-conductive material.

  11. The protist Trichomonas vaginalis harbors multiple lineages of transcriptionally active Mutator-like elements

    PubMed Central

    Lopes, Fabrício R; Silva, Joana C; Benchimol, Marlene; Costa, Gustavo GL; Pereira, Gonçalo AG; Carareto, Claudia MA

    2009-01-01

    Background For three decades the Mutator system was thought to be exclusive of plants, until the first homolog representatives were characterized in fungi and in early-diverging amoebas earlier in this decade. Results Here, we describe and characterize four families of Mutator-like elements in a new eukaryotic group, the Parabasalids. These Trichomonas vaginalis Mutator- like elements, or TvMULEs, are active in T. vaginalis and patchily distributed among 12 trichomonad species and isolates. Despite their relatively distinctive amino acid composition, the inclusion of the repeats TvMULE1, TvMULE2, TvMULE3 and TvMULE4 into the Mutator superfamily is justified by sequence, structural and phylogenetic analyses. In addition, we identified three new TvMULE-related sequences in the genome sequence of Candida albicans. While TvMULE1 is a member of the MuDR clade, predominantly from plants, the other three TvMULEs, together with the C. albicans elements, represent a new and quite distinct Mutator lineage, which we named TvCaMULEs. The finding of TvMULE1 sequence inserted into other putative repeat suggests the occurrence a novel TE family not yet described. Conclusion These findings expand the taxonomic distribution and the range of functional motif of MULEs among eukaryotes. The characterization of the dynamics of TvMULEs and other transposons in this organism is of particular interest because it is atypical for an asexual species to have such an extreme level of TE activity; this genetic landscape makes an interesting case study for causes and consequences of such activity. Finally, the extreme repetitiveness of the T. vaginalis genome and the remarkable degree of sequence identity within its repeat families highlights this species as an ideal system to characterize new transposable elements. PMID:19622157

  12. The coelacanth: Can a “living fossil” have active transposable elements in its genome?

    PubMed Central

    Naville, Magali; Chalopin, Domitille; Casane, Didier; Laurenti, Patrick; Volff, Jean-Nicolas

    2015-01-01

    The coelacanth has long been regarded as a “living fossil,” with extant specimens looking very similar to fossils dating back to the Cretaceous period. The hypothesis of a slowly or even not evolving genome has been proposed to account for this apparent morphological stasis. While this assumption seems to be sustained by different evolutionary analyses on protein-coding genes, recent studies on transposable elements have provided more conflicting results. Indeed, the coelacanth genome contains many transposable elements and has been shaped by several major bursts of transposition during evolution. In addition, comparison of orthologous genomic regions from the genomes of the 2 extant coelacanth species L. chalumnae and L. menadoensis revealed multiple species-specific insertions, indicating transposable element recent activity and contribution to post-speciation genome divergence. These observations, which do not support the genome stasis hypothesis, challenge either the impact of transposable elements on organismal evolution or the status of the coelacanth as a “living fossil.” Closer inspection of fossil and molecular data indicate that, even if coelacanths might evolve more slowly than some other lineages due to demographic and/or ecological factors, this variation is still in the range of a “non-fossil” vertebrate species. PMID:26442185

  13. A developmentally regulated Caulobacter flagellar promoter is activated by 3' enhancer and IHF binding elements.

    PubMed Central

    Gober, J W; Shapiro, L

    1992-01-01

    The transcription of a group of flagellar genes is temporally and spatially regulated during the Caulobacter crescentus cell cycle. These genes all share the same 5' cis-regulatory elements: a sigma 54 promoter, a binding site for integration host factor (IHF), and an enhancer sequence, known as the ftr element. We have partially purified the ftr-binding proteins, and we show that they require the same enhancer sequences for binding as are required for transcriptional activation. We have also partially purified the Caulobacter homolog of IHF and demonstrate that it can facilitate in vitro integrase-mediated lambda recombination. Using site-directed mutagenesis, we provide the first demonstration that natural enhancer sequences and IHF binding elements that reside 3' to the sigma 54 promoter of a bacterial gene, flaNQ, are required for transcription of the operon, in vivo. The IHF protein and the ftr-binding protein is primarily restricted to the predivisional cell, the cell type in which these promoters are transcribed. flaNQ promoter expression is localized to the swarmer pole of the predivisional cell, as are other flagellar promoters that possess these regulatory sequences 5' to the start site. The requirement for an IHF binding site and an ftr-enhancer element in spatially transcribed flagellar promoters indicates that a common mechanism may be responsible for both temporal and polar transcription. Images PMID:1392079

  14. Experimental analysis of biasing elements for dielectric electro-active polymers

    NASA Astrophysics Data System (ADS)

    Hodgins, Micah; Seelecke, Stefan

    2011-04-01

    This paper presents an experimental investigation of three different, small profile and scalable DEAP actuators. These actuators are designed for use in small scale pumping and valve applications. The actuators used in this paper consist of a biasing element (either a mass, linear spring, or a non-linear spring) coupled with a circular dielectric electro-active polymer (DEAP). These mechanisms bias the DEAP allowing out-of-plane actuation when the voltage is cycled. A constant force input, a linear spring, and a non-linear spring are separately tested as the biasing element of a circular/diaphragm DEAP. Tests are systematically performed at various DEAP pre-deflections, biasing stiffness and electrical loading rates. The displacement stroke performance of each test is examined and analyzed. It was found that the non-linear spring provided the largest displacement stroke over two other biasing elements. It also showed better performance at higher electrical loading rates. Thus, of the three types of biasing tested the non-linear spring shows most promise for use in fluid pump/valve applications. Future work will include optimizing this biasing element for the current DEAP design.

  15. The Importance of Landscape Elements for Bat Activity and Species Richness in Agricultural Areas.

    PubMed

    Heim, Olga; Treitler, Julia T; Tschapka, Marco; Knörnschild, Mirjam; Jung, Kirsten

    2015-01-01

    Landscape heterogeneity is regarded as a key factor for maintaining biodiversity and ecosystem function in production landscapes. We investigated whether grassland sites at close vicinity to forested areas are more frequently used by bats. Considering that bats are important consumers of herbivorous insects, including agricultural pest, this is important for sustainable land management. Bat activity and species richness were assessed using repeated monitoring from May to September in 2010 with acoustic monitoring surveys on 50 grassland sites in the Biosphere Reserve Schorfheide-Chorin (North-East Germany). Using spatial analysis (GIS), we measured the closest distance of each grassland site to potentially connecting landscape elements (e.g., trees, linear vegetation, groves, running and standing water). In addition, we assessed the distance to and the percent land cover of forest remnants and urban areas in a 200 m buffer around the recording sites to address differences in the local landscape setting. Species richness and bat activity increased significantly with higher forest land cover in the 200 m buffer and at smaller distance to forested areas. Moreover, species richness increased in proximity to tree groves. Larger amount of forest land cover and smaller distance to forest also resulted in a higher activity of bats on grassland sites in the beginning of the year during May, June and July. Landscape elements near grassland sites also influenced species composition of bats and species richness of functional groups (open, edge and narrow space foragers). Our results highlight the importance of forested areas, and suggest that agricultural grasslands that are closer to forest remnants might be better buffered against outbreaks of agricultural pest insects due to higher species richness and higher bat activity. Furthermore, our data reveals that even for highly mobile species such as bats, a very dense network of connecting elements within the landscape is

  16. The Importance of Landscape Elements for Bat Activity and Species Richness in Agricultural Areas

    PubMed Central

    Heim, Olga; Treitler, Julia T.; Tschapka, Marco; Knörnschild, Mirjam; Jung, Kirsten

    2015-01-01

    Landscape heterogeneity is regarded as a key factor for maintaining biodiversity and ecosystem function in production landscapes. We investigated whether grassland sites at close vicinity to forested areas are more frequently used by bats. Considering that bats are important consumers of herbivorous insects, including agricultural pest, this is important for sustainable land management. Bat activity and species richness were assessed using repeated monitoring from May to September in 2010 with acoustic monitoring surveys on 50 grassland sites in the Biosphere Reserve Schorfheide-Chorin (North-East Germany). Using spatial analysis (GIS), we measured the closest distance of each grassland site to potentially connecting landscape elements (e.g., trees, linear vegetation, groves, running and standing water). In addition, we assessed the distance to and the percent land cover of forest remnants and urban areas in a 200 m buffer around the recording sites to address differences in the local landscape setting. Species richness and bat activity increased significantly with higher forest land cover in the 200 m buffer and at smaller distance to forested areas. Moreover, species richness increased in proximity to tree groves. Larger amount of forest land cover and smaller distance to forest also resulted in a higher activity of bats on grassland sites in the beginning of the year during May, June and July. Landscape elements near grassland sites also influenced species composition of bats and species richness of functional groups (open, edge and narrow space foragers). Our results highlight the importance of forested areas, and suggest that agricultural grasslands that are closer to forest remnants might be better buffered against outbreaks of agricultural pest insects due to higher species richness and higher bat activity. Furthermore, our data reveals that even for highly mobile species such as bats, a very dense network of connecting elements within the landscape is

  17. Observation of new spontaneous fission activities from elements 100 to 105

    SciTech Connect

    Somerville, L.P.

    1982-03-01

    Several new Spontaneous Fission (SF) activities have been found. No definite identification could be made for any of the new SF activities; however, half-lives and possible assignments to element-104 isotopes consistent with several cross bombardments include /sup 257/Rf(3.8 s, 14% SF), /sup 258/Rf(13 ms), /sup 259/Rf(approx. 3 s, 8% SF), /sup 260/Rf(approx. 20 ms), and /sup 262/Rf(approx. 50 ms). The 80-ms SF activity claimed by the Dubna group for the discovery of element 104 (/sup 260/104) was not observed. A difficulty exists in the interpretation that /sup 260/Rf is a approx. 20-ms SF activity: in order to be correct, for example, the SF activities with half-lives between 14 and 24 ms produced in the reactions 109- to 119-MeV /sup 18/O + /sup 248/Cm, 88- to 100-MeV /sup 15/N + /sup 249/Bk, and 96-MeV /sup 18/O + /sup 249/Cf must be other nuclides due to their large production cross sections, or the cross sections for production of /sup 260/Rf must be enhanced by unknown mechanisms. Based on calculated total production cross sections a possible approx. 1% electron-capture branch in /sup 258/Lr(4.5 s) to the SF emitter /sup 258/No(1.2 ms) and an upper limit of 0.05% for SF branching in /sup 254/No(55 s) were determined. Other measured half-lives from unknown nuclides produced in respective reactions include approx. 1.6 s (/sup 18/O + /sup 248/CM), indications of a approx. 47-s SF activity (75-MeV /sup 12/C + /sup 249/Cf), and two or more SF activities with 3 s less than or equal to T/sub 1/2/ less than or equal to 60 s (/sup 18/O + /sup 249/Bk). The most exciting conclusion of this work is that if the tentative assignments to even-even element 104 isotopes are correct, there would be a sudden change in the SF half-life systematics at element 104 which has been predicted theoretically and attributed to the disappearance of the second hump of the double-humped fission barrier.

  18. Diurnal biting activity and transmission of Onchocerca volvulus (Filariata: Onchocercidae) by Simulium yahense (Diptera: Simuliidae) in Liberia.

    PubMed

    Davis, J R; Wasserman, S S; Trpis, M

    1994-03-01

    To determine the influence of meterological factors on the diurnal biting cycle of Simulium yahense Vajime & Dunbar (a member of the Simulium damnosum Theoblad complex), we captured host-seeking females as they landed on the exposed lower legs of humans in the Harbel area of Liberia. Biting activity was greatest during the morning hours and was characterized by a unimodal harmonic curve. Although meteorological conditions had no decisive influence on the unimodal pattern of diurnal biting activity, hourly variation in the number of S. yahense captured at human bait was affected by meterological factors (i.e., the diurnal pattern of S. yahense biting activity is regulated by an internal clock, but the number of bits during any given hour is in response to meterological conditions). The transmission of Onchocerca volvulus (Leuckart) was highest during the morning hours when high transmission potentials were in phase with peak human activity and served to maintain the hyperendemicity of onchocerciasis in the Harbel area. PMID:8189413

  19. Penn State Activities in the NASA GSFC Transmissive Microshutter Array Technology Development Program

    NASA Technical Reports Server (NTRS)

    Ge, Jian

    2002-01-01

    This is a one year contract starting on April 1, 2001 to design the Rapid Infrared and Visible Multiple Object Spectrometer (RIVMOS) and its auxiliary dispersing elements, design and fabricate silicon grisms, and reduce testing data with silicon grisms. Here I report our progress made during the funding period.

  20. Attributing Climate Conditions for Stable Malaria Transmission to Human Activity in sub-Saharan Africa

    NASA Astrophysics Data System (ADS)

    Sheldrake, L.; Mitchell, D.; Allen, M. R.

    2015-12-01

    Temperature and precipitation limit areas of stable malaria transmission, but the effects of climate change on the disease remain controversial. Previously, studies have not separated the influence of anthropogenic climate change and natural variability, despite being an essential step in the attribution of climate change impacts. Ensembles of 2900 simulations of regional climate in sub-Saharan Africa for the year 2013, one representing realistic conditions and the other how climate might have been in the absence of human influence, were used to force a P.falciparium climate suitability model developed by the Mapping Malaria Risk in Africa project. Strongest signals were detected in areas of unstable transmission, indicating their heightened sensitivity to climatic factors. Evidently, impacts of human-induced climate change were unevenly distributed: the probability of conditions being suitable for stable malaria transmission were substantially reduced (increased) in the Sahel (Greater Horn of Africa (GHOA), particularly in the Ethiopian and Kenyan highlands). The length of the transmission season was correspondingly shortened in the Sahel and extended in the GHOA, by 1 to 2 months, including in Kericho (Kenya), where the role of climate change in driving recent malaria occurrence is hotly contested. Human-induced warming was primarily responsible for positive anomalies in the GHOA, while reduced rainfall caused negative anomalies in the Sahel. The latter was associated with anthropogenic impacts on the West African Monsoon, but uncertainty in the RCM's ability to reproduce precipitation trends in the region weakens confidence in the result. That said, outputs correspond well with broad-scale changes in observed endemicity, implying a potentially important contribution of anthropogenic climate change to the malaria burden during the past century. Results support the health-framing of climate risk and help indicate hotspots of climate vulnerability, providing

  1. Statins Increase Plasminogen Activator Inhibitor Type 1 Gene Transcription through a Pregnane X Receptor Regulated Element

    PubMed Central

    Stanley, Frederick M.; Linder, Kathryn M.; Cardozo, Timothy J.

    2015-01-01

    Plasminogen activator inhibitor type 1 (PAI-1) is a multifunctional protein that has important roles in inflammation and wound healing. Its aberrant regulation may contribute to many disease processes such as heart disease. The PAI-1 promoter is responsive to multiple inputs including cytokines, growth factors, steroids and oxidative stress. The statin drugs, atorvastatin, mevastatin and rosuvastatin, increased basal and stimulated expression of the PAI-1 promoter 3-fold. A statin-responsive, nuclear hormone response element was previously identified in the PAI-1 promoter, but it was incompletely characterized. We characterized this direct repeat (DR) of AGGTCA with a 3-nucleotide spacer at -269/-255 using deletion and directed mutagenesis. Deletion or mutation of this element increased basal transcription from the promoter suggesting that it repressed PAI-1 transcription in the unliganded state. The half-site spacing and the ligand specificity suggested that this might be a pregnane X receptor (PXR) responsive element. Computational molecular docking showed that atorvastatin, mevastatin and rosuvastatin were structurally compatible with the PXR ligand-binding pocket in its agonist conformation. Experiments with Gal4 DNA binding domain fusion proteins showed that Gal4-PXR was activated by statins while other DR + 3 binding nuclear receptor fusions were not. Overexpression of PXR further enhanced PAI-1 transcription in response to statins. Finally, ChIP experiments using Halo-tagged PXR and RXR demonstrated that both components of the PXR-RXR heterodimer bound to this region of the PAI-1 promoter. PMID:26379245

  2. Prompt gamma neutron activation analysis of toxic elements in radioactive waste packages.

    PubMed

    Ma, J-L; Carasco, C; Perot, B; Mauerhofer, E; Kettler, J; Havenith, A

    2012-07-01

    The French Alternative Energies and Atomic Energy Commission (CEA) and National Radioactive Waste Management Agency (ANDRA) are conducting an R&D program to improve the characterization of long-lived and medium activity (LL-MA) radioactive waste packages. In particular, the amount of toxic elements present in radioactive waste packages must be assessed before they can be accepted in repository facilities in order to avoid pollution of underground water reserves. To this aim, the Nuclear Measurement Laboratory of CEA-Cadarache has started to study the performances of Prompt Gamma Neutron Activation Analysis (PGNAA) for elements showing large capture cross sections such as mercury, cadmium, boron, and chromium. This paper reports a comparison between Monte Carlo calculations performed with the MCNPX computer code using the ENDF/B-VII.0 library and experimental gamma rays measured in the REGAIN PGNAA cell with small samples of nickel, lead, cadmium, arsenic, antimony, chromium, magnesium, zinc, boron, and lithium to verify the validity of a numerical model and gamma-ray production data. The measurement of a ∼20kg test sample of concrete containing toxic elements has also been performed, in collaboration with Forschungszentrum Jülich, to validate the model in view of future performance studies for dense and large LL-MA waste packages. PMID:22406218

  3. Lack of Active Onchocerca volvulus Transmission in the Northern Chiapas Focus of Mexico

    PubMed Central

    Rodríguez-Pérez, Mario A.; Unnasch, Thomas R.; Domínguez-Vázquez, Alfredo; Morales-Castro, Alba L.; Richards, Frank; Peña-Flores, Graciela P.; Orozco-Algarra, María Eugenia; Prado-Velasco, Gibert

    2010-01-01

    The northern Chiapas onchocerciasis focus has undergone 11 years of ivermectin mass treatment. No evidence of microfilariae in the cornea and/or anterior chamber of the eye or in skin snips was seen in residents examined in 2006 in two sentinel communities (upper limit of the 95% confidence interval [UL 95% CI] = 0.5% and 0.3%, respectively). In children 10 and under, 0 of 305 were found to harbor antibodies to Ov16, a marker of parasite exposure; 0 of 4,400 Simulium ochraceum s.l. collected in 2005 contained parasite DNA, giving an UL 95% CI for the infective rate of 0.9/2,000, and an UL 95% CI of the seasonal transmission potential of 1.2 L3/person. These data, assumed to be representative of the focus as a whole, suggest that there is no ongoing transmission of Onchocerca volvulus in the northern Chiapas focus. Community-wide treatments with ivermectin were halted in 2008, and a post-treatment surveillance phase was initiated. PMID:20595471

  4. Hoxa5 gene regulation: A gradient of binding activity to a brachial spinal cord element.

    PubMed

    Nowling, T; Zhou, W; Krieger, K E; Larochelle, C; Nguyen-Huu, M C; Jeannotte, L; Tuggle, C K

    1999-04-01

    The Hox genes cooperate in providing positional information needed for spatial and temporal patterning of the vertebrate body axis. However, the biological mechanisms behind spatial Hox expression are largely unknown. In transgenic mice, gene fusions between Hoxa5 (previously called Hox-1.3) 5' flanking regions and the lacZ reporter gene show tissue- and time-specific expression in the brachial spinal cord in day 11-13 embryos. A 604-bp regulatory region with enhancer properties directs this spatially specific expression. Fine-detail mapping of the enhancer has identified several elements involved in region-specific expression, including an element required for expression in the brachial spinal cord. Factors in embryonic day 12.5 nuclear extracts bind this element in electrophoretic mobility shift assays (EMSA) and protect three regions from DNase digestion. All three sites contain an AAATAA sequence and mutations at these sites reduce or abolish binding. Furthermore, this element binds specific individual embryonic proteins on a protein blot. The binding activity appears as a gradient along the anterior-posterior axis with two- to threefold higher levels observed in extracts from anterior regions than from posterior regions. In parallel with the EMSA, the proteins on the protein blot also show reduced binding to probes with mutations at the AAATAA sites. Most importantly, transgenic mice carrying Hoxa5/lacZ fusions with the three AAATAA sites mutated either do not express the transgene or have altered transgene expression. The brachial spinal cord element and its binding proteins are likely to be involved in spatial expression of Hoxa5 during development. PMID:10075847

  5. Speed of sound estimation with active PZT element for thermal monitoring during ablation therapy: feasibility study

    NASA Astrophysics Data System (ADS)

    Kim, Younsu; Guo, Xiaoyu; Cheng, Alexis; Boctor, Emad M.

    2016-04-01

    Controlling the thermal dose during ablation therapy is instrumental to successfully removing the tumor while preserving the surrounding healthy tissue. In the practical scenario, surgeons must be able to determine the ablation completeness in the tumor region. Various methods have been proposed to monitor it, one of which uses ultrasound since it is a common intraoperative imaging modality due to its non-invasive, cost-effective, and convenient natures. In our approach, we propose to use time of flight (ToF) information to estimate speed of sound changes. Accurate speed of sound estimation is crucial because it is directly correlated with temperature change and subsequent determination of ablation completeness. We divide the region of interest in a circular fashion with a variable radius from the ablator tip. We introduce the concept of effective speed of sound in each of the sub-regions. Our active PZT element control system facilitates this unique approach by allowing us to acquire one-way ToF information between the PZT element and each of the ultrasound elements. We performed a simulation and an experiment to verify feasibility of this method. The simulation result showed that we could compute the effective speed of sound within 0.02m/s error in our discrete model. We also perform a sensitivity analysis for this model. Most of the experimental results had less than 1% error. Simulation using a Gaussian continuous model with multiple PZT elements is also demonstrated. We simulate the effect of the element location one the optimization result.

  6. Evaluation of the JPL X-band 32 element active array. [for deep space communication

    NASA Technical Reports Server (NTRS)

    Boreham, J. F.; Postal, R. B.; Conroy, B. L.

    1979-01-01

    Tests performed on an X-band 32-element active array are described. Antenna pattern characteristics of the array were tested in its standard operating mode as well as several degraded performance modes, including failures of 1, 2, 3, 4, 8, 16, and 31 elements. Additionally, the array was characterized with the addition of a metallic shroud, and also characterized versus rf drive level and at a single off-axis electronic beamsteered position. Characterization was performed on several of the 3/4-watt, three-stage, X-band solid-state power amplifier modules. The characterization included swept amplitude response, amplitude and phase versus temperature from -20 to +60 C, and intermodulation distortion of selected modules. The array is described and conclusions and recommendations based upon the experience and results achieved are included.

  7. Distribution of trace elements in the human body determined by neutron activation analysis

    SciTech Connect

    Yukawa, M.; Suzuki-Yasumoto, M.; Amano, K.; Terai, M.

    1980-01-01

    Neutron activation analysis and instrumental semiconductor gamma-ray spectrometry were used for analysis of 20 trace elements in 10 autopsied human organs and tissues (liver, kidney, cerebrum, cerebellum, heart, muscle, pancreas, spleen, lung, and aorta) from 63 Japanese persons, whose ages ranged from 15 days to 85 yr. Distributions of aluminum, bromine, magnesium, manganese, rubidium, selenium, and vanadium in human body were almost uniform. High concentrations of cadmium were found in kidney and liver samples. There was a high mercury concentration in the liver, kidney, and brain samples. Concentrations of other elements (arsenic, gold, cobalt, chromium, copper, iron, indium, antimony, selenium, titanium, and zinc) in each organ or tissue are also presented in this paper.

  8. Interaction of electrically evoked activity with intrinsic dynamics of cultured cortical networks with and without functional fast GABAergic synaptic transmission

    PubMed Central

    Baltz, Thomas; Voigt, Thomas

    2015-01-01

    The modulation of neuronal activity by means of electrical stimulation is a successful therapeutic approach for patients suffering from a variety of central nervous system disorders. Prototypic networks formed by cultured cortical neurons represent an important model system to gain general insights in the input–output relationships of neuronal tissue. These networks undergo a multitude of developmental changes during their maturation, such as the excitatory–inhibitory shift of the neurotransmitter GABA. Very few studies have addressed how the output properties to a given stimulus change with ongoing development. Here, we investigate input–output relationships of cultured cortical networks by probing cultures with and without functional GABAAergic synaptic transmission with a set of stimulation paradigms at various stages of maturation. On the cellular level, low stimulation rates (<15 Hz) led to reliable neuronal responses; higher rates were increasingly ineffective. Similarly, on the network level, lowest stimulation rates (<0.1 Hz) lead to maximal output rates at all ages, indicating a network wide refractory period after each stimulus. In cultures aged 3 weeks and older, a gradual recovery of the network excitability within tens of milliseconds was in contrast to an abrupt recovery after about 5 s in cultures with absent GABAAergic synaptic transmission. In these GABA deficient cultures evoked responses were prolonged and had multiple discharges. Furthermore, the network excitability changed periodically, with a very slow spontaneous change of the overall network activity in the minute range, which was not observed in cultures with absent GABAAergic synaptic transmission. The electrically evoked activity of cultured cortical networks, therefore, is governed by at least two potentially interacting mechanisms: A refractory period in the order of a few seconds and a very slow GABA dependent oscillation of the network excitability. PMID:26236196

  9. Interaction of electrically evoked activity with intrinsic dynamics of cultured cortical networks with and without functional fast GABAergic synaptic transmission.

    PubMed

    Baltz, Thomas; Voigt, Thomas

    2015-01-01

    The modulation of neuronal activity by means of electrical stimulation is a successful therapeutic approach for patients suffering from a variety of central nervous system disorders. Prototypic networks formed by cultured cortical neurons represent an important model system to gain general insights in the input-output relationships of neuronal tissue. These networks undergo a multitude of developmental changes during their maturation, such as the excitatory-inhibitory shift of the neurotransmitter GABA. Very few studies have addressed how the output properties to a given stimulus change with ongoing development. Here, we investigate input-output relationships of cultured cortical networks by probing cultures with and without functional GABAAergic synaptic transmission with a set of stimulation paradigms at various stages of maturation. On the cellular level, low stimulation rates (<15 Hz) led to reliable neuronal responses; higher rates were increasingly ineffective. Similarly, on the network level, lowest stimulation rates (<0.1 Hz) lead to maximal output rates at all ages, indicating a network wide refractory period after each stimulus. In cultures aged 3 weeks and older, a gradual recovery of the network excitability within tens of milliseconds was in contrast to an abrupt recovery after about 5 s in cultures with absent GABAAergic synaptic transmission. In these GABA deficient cultures evoked responses were prolonged and had multiple discharges. Furthermore, the network excitability changed periodically, with a very slow spontaneous change of the overall network activity in the minute range, which was not observed in cultures with absent GABAAergic synaptic transmission. The electrically evoked activity of cultured cortical networks, therefore, is governed by at least two potentially interacting mechanisms: A refractory period in the order of a few seconds and a very slow GABA dependent oscillation of the network excitability. PMID:26236196

  10. Trace element landscape of resting and activated human neutrophils on the sub-micrometer level.

    PubMed

    Niemiec, M J; De Samber, B; Garrevoet, J; Vergucht, E; Vekemans, B; De Rycke, R; Björn, E; Sandblad, L; Wellenreuther, G; Falkenberg, G; Cloetens, P; Vincze, L; Urban, C F

    2015-06-01

    Every infection is a battle for trace elements. Neutrophils migrate first to the infection site and accumulate quickly to high numbers. They fight pathogens by phagocytosis and intracellular toxication. Additionally, neutrophils form neutrophil extracellular traps (NETs) to inhibit extracellular microbes. Yet, neutrophil trace element characteristics are largely unexplored. We investigated unstimulated and phorbol myristate acetate-stimulated neutrophils using synchrotron radiation X-ray fluorescence (SR-XRF) on the sub-micron spatial resolution level. PMA activates pinocytosis, cytoskeletal rearrangements and the release of NETs, all mechanisms deployed by neutrophils to combat infection. By analyzing Zn, Fe, Cu, Mn, P, S, and Ca, not only the nucleus but also vesicular granules were identifiable in the elemental maps. Inductively Coupled Plasma Mass Spectrometry (ICP-MS) revealed a neutrophil-specific composition of Zn, Fe, Cu, and Mn in comparison with J774 and HeLa cells, indicating a neutrophil-specific metallome complying with their designated functions. When investigating PMA-activated neutrophils, the SR-XRF analysis depicted typical subcellular morphological changes: the transformation of nucleus and granules and the emergence of void vacuoles. Mature NETs were evenly composed of Fe, P, S, and Ca with occasional hot spots containing Zn, Fe, and Ca. An ICP-MS-based quantification of NET supernatants revealed a NETosis-induced decrease of soluble Zn, whereas Fe, Cu, and Mn concentrations were only slightly affected. In summary, we present a combination of SR-XRF and ICP-MS as a powerful tool to analyze trace elements in human neutrophils. The approach will be applicable and valuable to numerous aspects of nutritional immunity. PMID:25832493

  11. Extracellular Ca2+ depletion contributes to fast activity-dependent modulation of synaptic transmission in the brain.

    PubMed

    Rusakov, D A; Fine, A

    2003-01-23

    Synaptic activation is associated with rapid changes in intracellular Ca(2+), while the extracellular Ca(2+) level is generally assumed to be constant. Here, using a novel optical method to measure changes in extracellular Ca(2+) at high spatial and temporal resolution, we find that brief trains of synaptic transmission in hippocampal area CA1 induce transient depletion of extracellular Ca(2+). We show that this depletion, which depends on postsynaptic NMDA receptor activation, decreases the Ca(2+) available to enter individual presynaptic boutons of CA3 pyramidal cells. This in turn reduces the probability of consecutive synaptic releases at CA3-CA1 synapses and therefore contributes to short-term paired-pulse depression of minimal responses. This activity-dependent depletion of extracellular Ca(2+) represents a novel form of fast retrograde synaptic signaling that can modulate glutamatergic information transfer in the brain. PMID:12546823

  12. Extracellular Ca2+ Depletion Contributes to Fast Activity-Dependent Modulation of Synaptic Transmission in the Brain

    PubMed Central

    Rusakov, D.A.; Fine, A.

    2012-01-01

    Summary Synaptic activation is associated with rapid changes in intracellular Ca2+, while the extracellular Ca2+ level is generally assumed to be constant. Here, using a novel optical method to measure changes in extracellular Ca2+ at high spatial and temporal resolution, we find that brief trains of synaptic transmission in hippocampal area CA1 induce transient depletion of extracellular Ca2+. We show that this depletion, which depends on postsynaptic NMDA receptor activation, decreases the Ca2+ available to enter individual presynaptic boutons of CA3 pyramidal cells. This in turn reduces the probability of consecutive synaptic releases at CA3–CA1 synapses and therefore contributes to short-term paired-pulse depression of minimal responses. This activity-dependent depletion of extracellular Ca2+ represents a novel form of fast retrograde synaptic signaling that can modulate glutamatergic information transfer in the brain. PMID:12546823

  13. A protein kinase C isozyme is translocated to cytoskeletal elements on activation.

    PubMed Central

    Mochly-Rosen, D; Henrich, C J; Cheever, L; Khaner, H; Simpson, P C

    1990-01-01

    Protein kinase C (PKC)1 isozymes comprise a family of related cytosolic kinases that translocate to the cell particulate fraction on stimulation. The activated enzyme is thought to be on the plasma membrane. However, phosphorylation of protein substrates occurs throughout the cell and is inconsistent with plasma membrane localization. Using an isozyme-specific monoclonal antibody we found that, on activation, this PKC isozyme translocates to myofibrils in cardiac myocytes and to microfilaments in fibroblasts. Translocation of this activated PKC isozyme to cytoskeletal elements may explain some of the effects of PKC on cell contractility and morphology. In addition, differences in the translocation site of individual isozymes--and, therefore, phosphorylation of different substrates localized at these sites--may explain the diverse biological effects of PKC. Images PMID:2078573

  14. Innovative Application of Mechanical Activation for Rare Earth Elements Recovering: Process Optimization and Mechanism Exploration

    NASA Astrophysics Data System (ADS)

    Tan, Quanyin; Deng, Chao; Li, Jinhui

    2016-01-01

    With the rapidly expanding use of fluorescent lamps (FLs) and increasing interest in conservation and sustainable utilization of critical metals such as rare earth elements (REEs), the recovering of REEs from phosphors in waste FLs is becoming a critical environmental and economic issue. To effectively recycle REEs with metallurgical methods, mechanical activation by ball milling was introduced to pretreat the waste phosphors. This current study put the emphasis on the mechanical activation and leaching processes for REEs, and explored the feasibility of the method from both theoretical and practical standpoints. Results showed physicochemical changes of structural destruction and particle size reduction after mechanical activation, leading to the easy dissolution of REEs in the activated samples. Under optimal conditions, dissolution yields of 89.4%, 93.1% and 94.6% for Tb, Eu and Y, respectively, were achieved from activated waste phosphors using hydrochloric acid as the dissolution agent. The shrinking core model proved to be the most applicable for the leaching procedure, with an apparent activation energy of 10.96 ± 2.79 kJ/mol. This novel process indicates that mechanical activation is an efficient method for recovering REEs from waste phosphors, and it has promising potential for REE recovery with low cost and high efficiency.

  15. Innovative Application of Mechanical Activation for Rare Earth Elements Recovering: Process Optimization and Mechanism Exploration.

    PubMed

    Tan, Quanyin; Deng, Chao; Li, Jinhui

    2016-01-01

    With the rapidly expanding use of fluorescent lamps (FLs) and increasing interest in conservation and sustainable utilization of critical metals such as rare earth elements (REEs), the recovering of REEs from phosphors in waste FLs is becoming a critical environmental and economic issue. To effectively recycle REEs with metallurgical methods, mechanical activation by ball milling was introduced to pretreat the waste phosphors. This current study put the emphasis on the mechanical activation and leaching processes for REEs, and explored the feasibility of the method from both theoretical and practical standpoints. Results showed physicochemical changes of structural destruction and particle size reduction after mechanical activation, leading to the easy dissolution of REEs in the activated samples. Under optimal conditions, dissolution yields of 89.4%, 93.1% and 94.6% for Tb, Eu and Y, respectively, were achieved from activated waste phosphors using hydrochloric acid as the dissolution agent. The shrinking core model proved to be the most applicable for the leaching procedure, with an apparent activation energy of 10.96 ± 2.79 kJ/mol. This novel process indicates that mechanical activation is an efficient method for recovering REEs from waste phosphors, and it has promising potential for REE recovery with low cost and high efficiency. PMID:26819083

  16. Innovative Application of Mechanical Activation for Rare Earth Elements Recovering: Process Optimization and Mechanism Exploration

    PubMed Central

    Tan, Quanyin; Deng, Chao; Li, Jinhui

    2016-01-01

    With the rapidly expanding use of fluorescent lamps (FLs) and increasing interest in conservation and sustainable utilization of critical metals such as rare earth elements (REEs), the recovering of REEs from phosphors in waste FLs is becoming a critical environmental and economic issue. To effectively recycle REEs with metallurgical methods, mechanical activation by ball milling was introduced to pretreat the waste phosphors. This current study put the emphasis on the mechanical activation and leaching processes for REEs, and explored the feasibility of the method from both theoretical and practical standpoints. Results showed physicochemical changes of structural destruction and particle size reduction after mechanical activation, leading to the easy dissolution of REEs in the activated samples. Under optimal conditions, dissolution yields of 89.4%, 93.1% and 94.6% for Tb, Eu and Y, respectively, were achieved from activated waste phosphors using hydrochloric acid as the dissolution agent. The shrinking core model proved to be the most applicable for the leaching procedure, with an apparent activation energy of 10.96 ± 2.79 kJ/mol. This novel process indicates that mechanical activation is an efficient method for recovering REEs from waste phosphors, and it has promising potential for REE recovery with low cost and high efficiency. PMID:26819083

  17. Retrotransposon long interspersed nucleotide element-1 (LINE-1) is activated during salamander limb regeneration

    PubMed Central

    Zhu, Wei; Kuo, Dwight; Nathanson, Jason; Satoh, Akira; Pao, Gerald M.; Yeo, Gene W.; Bryant, Susan V.; Voss, S. Randal; Gardiner, David M.; Hunter, Tony

    2012-01-01

    Salamanders possess an extraordinary capacity for tissue and organ regeneration when compared to mammals. In our effort to characterize the unique transcriptional fingerprint emerging during the early phase of salamander limb regeneration, we identified transcriptional activation of some germline-specific genes within the Mexican axolotl (Ambystoma mexicanum) that is indicative of cellular reprogramming of differentiated cells into a germline-like state. In this work, we focus on one of these genes, the long interspersed nucleotide element-1 (LINE-1) retrotransposon, which is usually active in germ cells and silent in most of the somatic tissues in other organisms. LINE-1 was found to be dramatically upregulated during regeneration. In addition, higher genomic LINE-1 content was also detected in the limb regenerate when compared to that before amputation indicating that LINE-1 retrotransposition is indeed active during regeneration. Active LINE-1 retrotransposition has been suggested to have a potentially deleterious impact on genomic integrity. Silencing of activated LINE-1 by small RNAs has been reported to be part of the machinery aiming to maintain genomic integrity. Indeed, we were able to identify putative LINE-1-related piRNAs in the limb blastema. Transposable element-related piRNAs have been identified frequently in the germline in other organisms. Thus, we present here a scenario in which a unique germline-like state is established during axolotl limb regeneration, and the re-activation of LINE-1 may serve as a marker for cellular dedifferentiation in the early-stage of limb regeneration. PMID:22913491

  18. Structural elements in the Girk1 subunit that potentiate G protein-gated potassium channel activity.

    PubMed

    Wydeven, Nicole; Young, Daniele; Mirkovic, Kelsey; Wickman, Kevin

    2012-12-26

    G protein-gated inwardly rectifying K(+) (Girk/K(IR)3) channels mediate the inhibitory effect of many neurotransmitters on excitable cells. Girk channels are tetramers consisting of various combinations of four mammalian Girk subunits (Girk1 to -4). Although Girk1 is unable to form functional homomeric channels, its presence in cardiac and neuronal channel complexes correlates with robust channel activity. This study sought to better understand the potentiating influence of Girk1, using the GABA(B) receptor and Girk1/Girk2 heteromer as a model system. Girk1 did not increase the protein levels or alter the trafficking of Girk2-containing channels to the cell surface in transfected cells or hippocampal neurons, indicating that its potentiating influence involves enhancement of channel activity. Structural elements in both the distal carboxyl-terminal domain and channel core were identified as key determinants of robust channel activity. In the distal carboxyl-terminal domain, residue Q404 was identified as a key determinant of receptor-induced channel activity. In the Girk1 core, three unique residues in the pore (P) loop (F137, A142, Y150) were identified as a collective potentiating influence on both receptor-dependent and receptor-independent channel activity, exerting their influence, at least in part, by enhancing mean open time and single-channel conductance. Interestingly, the potentiating influence of the Girk1 P-loop is tempered by residue F162 in the second membrane-spanning domain. Thus, discontinuous and sometime opposing elements in Girk1 underlie the Girk1-dependent potentiation of receptor-dependent and receptor-independent heteromeric channel activity. PMID:23236146

  19. Aortic ascorbic acid, trace elements, and superoxide dismutase activity in human aneurysmal and occlusive disease

    SciTech Connect

    Dubick, M.A.; Hunter, G.C.; Casey, S.M.; Keen, C.L.

    1987-02-01

    Altered trace elements and ascorbic acid metabolism have been implicated in the pathogenesis of atherosclerotic cardiovascular disease. However, their role in the disease process, or the effect of atherosclerosis on their tissue levels within plaque, is poorly understood. The presence study analyzes the concentrations of Fe, Cu, Zn, and Mn, and ascorbic acid and superoxide dismutase (SOD) activity in tissue samples from 29 patients with abdominal aortic aneurysms (AAA) and 14 patients with atherosclerotic occlusive disease (AOD). It was observed that the Fe and Mn concentrations in AAA and AOD tissue were higher than the levels in nondiseased control aorta, whereas Cu and Zn levels in AAA and AOD tissue were similar to the levels in controls. The Zn:Cu ratio was significantly lower in the AAA tissue in comparison to both AOD and control tissue. In addition, AAA and AOD tissue had low ascorbic acid levels and low Cu, Zn-SOD activity with Cu,Zn-SOD:Mn-SOD ratios of 0.27 and 0.19, respectively, compared to a ratio of 3.20 in control aorta. These data indicate that aorta affected by aneurysms and occlusive disease have altered trace element and ascorbic acid concentrations, as well as low Cu,Zn-SOD activity. Although these observations do not directly support the hypothesis that AAA is associated with aortic Cu deficiency they do suggest a role for oxygen radicals or increased lipid peroxidation in occlusive and aneurysmal disease of the aorta.

  20. Transcription of Mammalian cis-Regulatory Elements Is Restrained by Actively Enforced Early Termination.

    PubMed

    Austenaa, Liv M I; Barozzi, Iros; Simonatto, Marta; Masella, Silvia; Della Chiara, Giulia; Ghisletti, Serena; Curina, Alessia; de Wit, Elzo; Bouwman, Britta A M; de Pretis, Stefano; Piccolo, Viviana; Termanini, Alberto; Prosperini, Elena; Pelizzola, Mattia; de Laat, Wouter; Natoli, Gioacchino

    2015-11-01

    Upon recruitment to active enhancers and promoters, RNA polymerase II (Pol II) generates short non-coding transcripts of unclear function. The mechanisms that control the length and the amount of ncRNAs generated by cis-regulatory elements are largely unknown. Here, we show that the adaptor protein WDR82 and its associated complexes actively limit such non-coding transcription. WDR82 targets the SET1 H3K4 methyltransferases and the nuclear protein phosphatase 1 (PP1) complexes to the initiating Pol II. WDR82 and PP1 also interact with components of the transcriptional termination and RNA processing machineries. Depletion of WDR82, SET1, or the PP1 subunit required for its nuclear import caused distinct but overlapping transcription termination defects at highly expressed genes and active enhancers and promoters, thus enabling the increased synthesis of unusually long ncRNAs. These data indicate that transcription initiated from cis-regulatory elements is tightly coordinated with termination mechanisms that impose the synthesis of short RNAs. PMID:26593720

  1. Glucose Enhances Basal or Melanocortin-Induced cAMP-Response Element Activity in Hypothalamic Cells.

    PubMed

    Breit, Andreas; Wicht, Kristina; Boekhoff, Ingrid; Glas, Evi; Lauffer, Lisa; Mückter, Harald; Gudermann, Thomas

    2016-07-01

    Melanocyte-stimulating hormone (MSH)-induced activation of the cAMP-response element (CRE) via the CRE-binding protein in hypothalamic cells promotes expression of TRH and thereby restricts food intake and increases energy expenditure. Glucose also induces central anorexigenic effects by acting on hypothalamic neurons, but the underlying mechanisms are not completely understood. It has been proposed that glucose activates the CRE-binding protein-regulated transcriptional coactivator 2 (CRTC-2) in hypothalamic neurons by inhibition of AMP-activated protein kinases (AMPKs), but whether glucose directly affects hypothalamic CRE activity has not yet been shown. Hence, we dissected effects of glucose on basal and MSH-induced CRE activation in terms of kinetics, affinity, and desensitization in murine, hypothalamic mHypoA-2/10-CRE cells that stably express a CRE-dependent reporter gene construct. Physiologically relevant increases in extracellular glucose enhanced basal or MSH-induced CRE-dependent gene transcription, whereas prolonged elevated glucose concentrations reduced the sensitivity of mHypoA-2/10-CRE cells towards glucose. Glucose also induced CRCT-2 translocation into the nucleus and the AMPK activator metformin decreased basal and glucose-induced CRE activity, suggesting a role for AMPK/CRTC-2 in glucose-induced CRE activation. Accordingly, small interfering RNA-induced down-regulation of CRTC-2 expression decreased glucose-induced CRE-dependent reporter activation. Of note, glucose also induced expression of TRH, suggesting that glucose might affect the hypothalamic-pituitary-thyroid axis via the regulation of hypothalamic CRE activity. These findings significantly advance our knowledge about the impact of glucose on hypothalamic signaling and suggest that TRH release might account for the central anorexigenic effects of glucose and could represent a new molecular link between hyperglycaemia and thyroid dysfunction. PMID:27144291

  2. Activation of carbohydrate response element binding protein (ChREBP) by ethanol

    PubMed Central

    Liangpunsakul, Suthat; Ross, Ruth A.; Crabb, David W.

    2012-01-01

    Carbohydrate response element binding protein (ChREBP) is a transcription factor involved in hepatic lipogenesis. Its function is in part under the control of AMP-activated protein kinase (AMPK) and protein phosphatase 2A (PP2A). Given known effects of ethanol on AMPK and PP2A, it is plausible that ethanol might enhance fatty acid synthesis by increasing the activity of ChREBP. We hypothesized that another potential pathway of ethanol-induced hepatic steatosis is mediated by activation of ChREBP. Methods The effects of ethanol on ChREBP were assessed in hepatoma cells and in C57BL/6J mice fed with the Lieber-DeCarli diet. Results When the cells were exposed to ethanol (50 mM) for 24 hrs, the activity of a liver pyruvate kinase (LPK) promoter-luciferase reporter was increased by ~4-fold. Ethanol feeding of mice resulted in the translocation of ChREBP from cytosol to the nucleus. PP2A activity was increased in the liver of ethanol-fed mice by 22%. We found no difference in the levels of hepatic Xu-5-P between ethanol-fed mice and controls. Transfection of a constitutively active AMPK expression plasmid suppressed the basal activity of the LPK luciferase reporter and abolished the effect of ethanol on the reporter activity. However, transfection of rat hepatoma cells with a dominant negative AMPK expression plasmid induced basal LPK luciferase activity by only ~20%. The effect of ethanol on ChREBP was attenuated in the presence of okadaic acid, an inhibitor of PP2A. Conclusions The effects of ethanol on AMPK and PP2A may result in activation of ChREBP, providing another potential mechanism for ethanol-induced hepatic steatosis. However, additional okadaic acid-insensitive effects appear to be important as well. PMID:23266705

  3. The nature of catalytically active complexes of Ziegler-type systems based on iron subgroup elements

    SciTech Connect

    Brodskii, A.R.; Noskova, N.F.

    1995-02-01

    Complexation processes that occur in Ziegler-type systems on the basis of the carboxylate compounds of elements belonging mainly to the Iron Subgroup are investigated. The influence of genesis on the composition and structure of the complexes forming in the catalytic systems is demonstrated. A general scheme to describe the interaction of the catalyst components depending on their formation conditions is proposed. It is established that, along with other complexes, polynuclear associated species are present in the catalysts and play a decisive role in the catalytic activity of the investigated systems.

  4. Sensing Nature's Electric Fields: Ion Channels as Active Elements of Linear Amplification

    NASA Astrophysics Data System (ADS)

    Bezrukov, Sergey M.

    2003-05-01

    Given the parameters of familiar cellular elements — voltage-sensitive ion channels, carriers, pumps, phospholipid insulators, and electrolytic conductors — is it possible to construct an amplifier whose sensitivity matches the 5 nV/cm threshold found in behavioral experiments on elasmobranch fish? Or, in addition to clever circuitry that uses commonly known elements and principles, do we need something else to understand this sensitivity? The resolution of this question is important not only for studies in sensory biophysics seeking to reveal underlying mechanisms and molecular structures. More generally, it deepens our appreciation of the stochastic nature of inter- and intra-cellular control circuits. Here I analyze a simplified circuit involving negative differential resistance of voltage-sensitive ion channels. The analysis establishes an off-equilibrium criterion for amplification, shows that ion channels are the dominant noise sources, and, by minimizing channel noise within the given constraints, demonstrates that generic voltage-sensitive ion channels are likely candidates for the active elements of the linear cellular amplifiers. Finally, I highlight a number of unsolved issues.

  5. Reward Contingency Modulates Neuronal Activity in Rat Septal Nuclei during Elemental and Configural Association Tasks

    PubMed Central

    Matsuyama, Nozomu; Uwano, Teruko; Hori, Etsuro; Ono, Taketoshi; Nishijo, Hisao

    2011-01-01

    It has been suggested that septal nuclei are important in the control of behavior during various reward and non-reward situations. In the present study, neuronal activity was recorded from rat septal nuclei during discrimination of conditioned sensory stimuli (CSs) of the medial forebrain bundle associated with or without a reward (sucrose solution or intracranial self-stimulation, ICSS). Rats were trained to lick a spout protruding close to the mouth just after a CS to obtain a reward stimulus. The CSs included both elemental and configural stimuli. In the configural condition, the reward contingency of the stimuli presented together was opposite to that of each elemental stimulus presented alone, although the same sensory stimuli were involved. Of the 72 responsive septal neurons, 18 responded selectively to the CSs predicting reward (CS+-related), four to the CSs predicting non-reward (CS0-related), nine to some CSs predicting reward or non-reward, and 15 non-differentially to all CSs. The remaining 26 neurons responded mainly during the ingestion/ICSS phase. A multivariate analysis of the septal neuronal responses to elemental and configural stimuli indicated that septal neurons encoded the CSs based on reward contingency, regardless of the stimulus physical properties and were categorized into three groups; CSs predicting the sucrose solution, CSs predicting a non-reward, and CSs predicting ICSS. The results suggest that septal nuclei are deeply involved in discriminating the reward contingency of environmental stimuli to manifest appropriate behaviors in response to changing stimuli. PMID:21633493

  6. Rotorcraft transmission

    NASA Technical Reports Server (NTRS)

    Coy, John J.

    1987-01-01

    The NASA Lewis Research Center and the U.S. Army Aviation Systems Command share an interest in advancing the technology for helicopter propulsion systems. In particular, this presentation outlines that portion of the program that applies to the drive train and its various mechanical components. The major goals of the program are to increase the life, reliability, and maintainability; reduce the weight, noise, and vibration; and maintain the relatively high mechanical efficiency of the gear train. The current activity emphasizes noise reduction technology and analytical code development followed by experimental verification. Selected significant advances in technology for transmissions are reviewed, including advanced configurations and new analytical tools. Finally, the plan for transmission research in the future is presented.

  7. Down hole transmission system

    DOEpatents

    Hall, David R.; Hall, Jr., H. Tracy

    2007-07-24

    A transmission system in a downhole component comprises a data transmission element in both ends of the downhole component. Each data transmission element houses an electrically conducting coil in a MCEI circular trough. The electrically conducting coil comprises at least two generally fractional loops. In the preferred embodiment, the transmission elements are connected by an electrical conductor. Preferably, the electrical conductor is a coaxial cable. Preferably, the MCEI trough comprises ferrite. In the preferred embodiment, the fractional loops are connected by a connecting cable. In one aspect of the present invention, the connecting cable is a pair of twisted wires. In one embodiment the connecting cable is a shielded pair of twisted wires. In another aspect of the present invention, the connecting cable is a coaxial cable. The connecting cable may be disposed outside of the MCEI circular trough.

  8. Evaluation of a combination of continuum and truss finite elements in a model of passive and active muscle tissue.

    PubMed

    Hedenstierna, S; Halldin, P; Brolin, K

    2008-12-01

    The numerical method of finite elements (FE) is a powerful tool for analysing stresses and strains in the human body. One area of increasing interest is the skeletal musculature. This study evaluated modelling of skeletal muscle tissue using a combination of passive non-linear, viscoelastic solid elements and active Hill-type truss elements, the super-positioned muscle finite element (SMFE). The performance of the combined materials and elements was evaluated for eccentric motions by simulating a tensile experiment from a published study on a stimulated rabbit muscle including three different strain rates. It was also evaluated for isometric and concentric contractions. The resulting stress-strain curves had the same overall pattern as the experiments, with the main limitation being sensitivity to the active force-length relation. It was concluded that the SMFE could model active and passive muscle tissue at constant rate elongations for strains below failure, as well as isometric and concentric contractions. PMID:18642161

  9. Selective optical control of synaptic transmission in the subcortical visual pathway by activation of viral vector-expressed halorhodopsin.

    PubMed

    Kaneda, Katsuyuki; Kasahara, Hironori; Matsui, Ryosuke; Katoh, Tomoko; Mizukami, Hiroaki; Ozawa, Keiya; Watanabe, Dai; Isa, Tadashi

    2011-01-01

    The superficial layer of the superior colliculus (sSC) receives visual inputs via two different pathways: from the retina and the primary visual cortex. However, the functional significance of each input for the operation of the sSC circuit remains to be identified. As a first step toward understanding the functional role of each of these inputs, we developed an optogenetic method to specifically suppress the synaptic transmission in the retino-tectal pathway. We introduced enhanced halorhodopsin (eNpHR), a yellow light-sensitive, membrane-targeting chloride pump, into mouse retinal ganglion cells (RGCs) by intravitreously injecting an adeno-associated virus serotype-2 vector carrying the CMV-eNpHR-EYFP construct. Several weeks after the injection, whole-cell recordings made from sSC neurons in slice preparations revealed that yellow laser illumination of the eNpHR-expressing retino-tectal axons, putatively synapsing onto the recorded cells, effectively inhibited EPSCs evoked by electrical stimulation of the optic nerve layer. We also showed that sSC spike activities elicited by visual stimulation were significantly reduced by laser illumination of the sSC in anesthetized mice. These results indicate that photo-activation of eNpHR expressed in RGC axons enables selective blockade of retino-tectal synaptic transmission. The method established here can most likely be applied to a variety of brain regions for studying the function of individual inputs to these regions. PMID:21483674

  10. Conditional Spike Transmission Mediated by Electrical Coupling Ensures Millisecond Precision-Correlated Activity among Interneurons In Vivo.

    PubMed

    van Welie, Ingrid; Roth, Arnd; Ho, Sara S N; Komai, Shoji; Häusser, Michael

    2016-05-18

    Many GABAergic interneurons are electrically coupled and in vitro can display correlated activity with millisecond precision. However, the mechanisms underlying correlated activity between interneurons in vivo are unknown. Using dual patch-clamp recordings in vivo, we reveal that in the presence of spontaneous background synaptic activity, electrically coupled cerebellar Golgi cells exhibit robust millisecond precision-correlated activity which is enhanced by sensory stimulation. This precisely correlated activity results from the cooperative action of two mechanisms. First, electrical coupling ensures slow subthreshold membrane potential correlations by equalizing membrane potential fluctuations, such that coupled neurons tend to approach action potential threshold together. Second, fast spike-triggered spikelets transmitted through gap junctions conditionally trigger postjunctional spikes, depending on both neurons being close to threshold. Electrical coupling therefore controls the temporal precision and degree of both spontaneous and sensory-evoked correlated activity between interneurons, by the cooperative effects of shared synaptic depolarization and spikelet transmission. PMID:27161527

  11. Automatic transmission

    SciTech Connect

    Miura, M.; Inuzuka, T.

    1986-08-26

    1. An automatic transmission with four forward speeds and one reverse position, is described which consists of: an input shaft; an output member; first and second planetary gear sets each having a sun gear, a ring gear and a carrier supporting a pinion in mesh with the sun gear and ring gear; the carrier of the first gear set, the ring gear of the second gear set and the output member all being connected; the ring gear of the first gear set connected to the carrier of the second gear set; a first clutch means for selectively connecting the input shaft to the sun gear of the first gear set, including friction elements, a piston selectively engaging the friction elements and a fluid servo in which hydraulic fluid is selectively supplied to the piston; a second clutch means for selectively connecting the input shaft to the sun gear of the second gear set a third clutch means for selectively connecting the input shaft to the carrier of the second gear set including friction elements, a piston selectively engaging the friction elements and a fluid servo in which hydraulic fluid is selectively supplied to the piston; a first drive-establishing means for selectively preventing rotation of the ring gear of the first gear set and the carrier of the second gear set in only one direction and, alternatively, in any direction; a second drive-establishing means for selectively preventing rotation of the sun gear of the second gear set; and a drum being open to the first planetary gear set, with a cylindrical intermediate wall, an inner peripheral wall and outer peripheral wall and forming the hydraulic servos of the first and third clutch means between the intermediate wall and the inner peripheral wall and between the intermediate wall and the outer peripheral wall respectively.

  12. Total coliphages removal by activated sludge process and their morphological diversity by transmission electron microscopy.

    PubMed

    Jebri, Sihem; Hmaied, Fatma; Yahya, Mariem; Ben Ammar, Aouatef; Hamdi, Moktar

    2016-01-01

    This study was conducted to isolate phages in treated sewage collected from wastewater treatment plant, and explore their morphological diversity by transmission electron microscopy (TEM). Fates of total bacteriophages and their reduction by biological treatment were also assayed. Phages were isolated using the plaque assay then negatively stained and observed by electron microscope. Electron micrographs showed different types of phages with different shapes and sizes. The majority of viruses found in treated sewage ranged from 30 to 100 nm in capsid diameter. Many of them were tailed, belonging to Siphoviridae, Myoviridae and Podoviridae families. Non-tailed phage particles were also found at a low rate, presumably belonging to Leviviridae or Microviridae families. This study shows the diversity and the abundance of bacteriophages in wastewater after biological treatment. Their persistence in wastewater reused in agriculture should raise concerns about their potential role in controlling bacterial populations in the environment. They should be also included in water treatment quality controlling guidelines as fecal and viral indicators. PMID:27438235

  13. Predominance of modern Mycobacterium tuberculosis strains and active transmission of Beijing sublineage in Jayapura, Indonesia Papua.

    PubMed

    Chaidir, Lidya; Sengstake, Sarah; de Beer, Jessica; Oktavian, Antonius; Krismawati, Hana; Muhapril, Erfin; Kusumadewi, Inri; Annisa, Jessi; Anthony, Richard; van Soolingen, Dick; Achmad, Tri Hanggono; Marzuki, Sangkot; Alisjahbana, Bachti; van Crevel, Reinout

    2016-04-01

    Mycobacterium tuberculosis genotype distribution is different between West and Central Indonesia, but there are no data on the most Eastern part, Papua. We aimed to identify the predominant genotypes of M. tuberculosis responsible for tuberculosis in coastal Papua, their transmission, and the association with patient characteristics. A total of 199 M. tuberculosis isolates were collected. Spoligotyping was applied to describe the population structure of M. tuberculosis, lineage identification was performed using a combination of lineage-specific markers, and genotypic clusters were identified using a combination of 24-locus-MIRU-VNTR and spoligotyping. A high degree of genetic diversity was observed among isolates based on their spoligopatterns. Strains from modern lineage 4 made up almost half of strains (46.9%), being more abundant than the ancient lineage 1 (33.7%), and modern lineage 2 (19.4%). Thirty-five percent of strains belonged to genotypic clusters, especially strains in the Beijing genotype. Previous TB treatment and mutations associated with drug resistance were more common in patients infected with strains of the Beijing genotype. Papua shows a different distribution of M. tuberculosis genotypes compared to other parts of Indonesia. Clustering and drug resistance of modern strains recently introduced to Papua may contribute to the high tuberculosis burden in this region. PMID:26825253

  14. Active magnetic bearings used as exciters for rolling element bearing outer race defect diagnosis.

    PubMed

    Xu, Yuanping; Di, Long; Zhou, Jin; Jin, Chaowu; Guo, Qintao

    2016-03-01

    The active health monitoring of rotordynamic systems in the presence of bearing outer race defect is considered in this paper. The shaft is assumed to be supported by conventional mechanical bearings and an active magnetic bearing (AMB) is used in the mid of the shaft location as an exciter to apply electromagnetic force to the system. We investigate a nonlinear bearing-pedestal system model with the outer race defect under the electromagnetic force. The nonlinear differential equations are integrated using the fourth-order Runge-Kutta algorithm. The simulation and experimental results show that the characteristic signal of outer race incipient defect is significantly amplified under the electromagnetic force through the AMBs, which is helpful to improve the diagnosis accuracy of rolling element bearing׳s incipient outer race defect. PMID:26803551

  15. [Antilipoxygenase activity and the trace elements content of Aloe vera in relation to the therapeutical effect].

    PubMed

    Bezáková, L; Oblozinský, M; Sýkorová, M; Paulíková, I; Kostálová, D

    2005-01-01

    Aloe vera is a rich source of many natural-health-promoting substances. The results of contemporary research on animal models indicate that the extracts have an antiinflammatory property. In this work the results of some in vitro experiments are shown: determination of the inhibitory effect of the Aloe vera extracts on the activity of partially purified lipoxygenase from the rat lung cytosol fraction, and quantitative determination of the trace elements presented in the extract (Mn, Fe, Cu, Zn) carried out by using the x-ray fluorescence analysis. The findings could explain the inhibitory effect (antilipoxygenase activity) of the Aloe vera extract in the acute inflammation process, expecially in the topical application for healing of minor burns and skin ulcers. PMID:15751795

  16. Human Research Program Human Health Countermeasures Element Extravehicular Activity (EVA) Risk Standing Review Panel (SRP)

    NASA Technical Reports Server (NTRS)

    Norfleet, William; Harris, Bernard

    2009-01-01

    The Extravehicular Activity (EVA) Risk Standing Review Panel (SRP) was favorably impressed by the operational risk management approach taken by the Human Research Program (HRP) Integrated Research Plan (IRP) to address the stated life sciences issues. The life sciences community at the Johnson Space Center (JSC) seems to be focused on operational risk management. This approach is more likely to provide risk managers with the information they need at the time they need it. Concerning the information provided to the SRP by the EVA Physiology, Systems, and Performance Project (EPSP), it is obvious that a great deal of productive activity is under way. Evaluation of this information was hampered by the fact that it often was not organized in a fashion that reflects the "Gaps and Tasks" approach of the overall Human Health Countermeasures (HHC) effort, and that a substantial proportion of the briefing concerned subjects that, while interesting, are not part of the HHC Element (e.g., the pressurized rover presentation). Additionally, no information was provided on several of the tasks or how they related to work underway or already accomplished. This situation left the SRP having to guess at the efforts and relationship to other elements, and made it hard to easily map the EVA Project efforts currently underway, and the data collected thus far, to the gaps and tasks in the IRP. It seems that integration of the EPSP project into the HHC Element could be improved. Along these lines, we were concerned that our SRP was split off from the other participating SRPs at an early stage in the overall agenda for the meeting. In reality, the concerns of EPSP and other projects share much common ground. For example, the commonality of the concerns of the EVA and exercise physiology groups is obvious, both in terms of what reduced exercise capacity can do to EVA capability, and how the exercise performed during an EVA could contribute to an overall exercise countermeasure prescription.

  17. Synergistic effect of 5-HT1A and σ1 receptor activation on prefrontal dopaminergic transmission under circulating steroid deficiency.

    PubMed

    Hiramatsu, Naoki; Ago, Yukio; Hasebe, Shigeru; Nishimura, Akira; Mori, Kazuya; Takuma, Kazuhiro; Matsuda, Toshio

    2013-12-01

    Serotonin (5-HT)1A and σ1 receptors have been implicated in psychiatric disorders. We previously found that combined 5-HT reuptake inhibition and σ1 receptor activation has a synergistic effect on prefrontal dopaminergic transmission in adrenalectomized/castrated mice lacking circulating steroid hormones. In the present study, we examined the mechanisms underlying this neurochemical synergism. Systemic administration of fluvoxamine, a selective 5-HT reuptake inhibitor with agonistic activity towards the σ1 receptor, increased prefrontal dopamine (DA) levels, and adrenalectomy/castration potentiated this fluvoxamine-induced increase in DA. This enhancement of DA release was blocked by WAY100635 (a 5-HT1A receptor antagonist), but not by ritanserin (a 5-HT2 receptor antagonist), azasetron (a 5-HT3 receptor antagonist) or SB269970 (a 5-HT7 receptor antagonist). Individually, osemozotan (a 5-HT1A receptor agonist) and (+)-SKF-10,047 (a σ1 receptor agonist) did not alter prefrontal monoamine levels in adrenalectomized/castrated and sham-operated mice differentially. In contrast, co-administration of these drugs increased prefrontal DA levels to a greater extent in adrenalectomized/castrated mice than in sham-operated animals. Furthermore, co-administration of osemozotan and (+)-SKF-10,047 increased expression of the neuronal activity marker c-Fos in the ventral tegmental area of adrenalectomized/castrated mice, but not in sham-operated animals. These findings suggest that combined activation of 5-HT1A and σ1 receptors has a synergistic effect on prefrontal dopaminergic transmission under circulating steroid deficiency, and that this interaction may play an important role in the regulation of the prefrontal DA system. PMID:23851260

  18. Active transposable elements recover species boundaries and geographic structure in Madagascan coffee species.

    PubMed

    Roncal, Julissa; Guyot, Romain; Hamon, Perla; Crouzillat, Dominique; Rigoreau, Michel; Konan, Olivier N'Guessan; Rakotomalala, Jean-Jacques; Nowak, Michael D; Davis, Aaron P; de Kochko, Alexandre

    2016-02-01

    The completion of the genome assembly for the economically important coffee plant Coffea canephora (Rubiaceae) has allowed the use of bioinformatic tools to identify and characterize a diverse array of transposable elements (TEs), which can be used in evolutionary studies of the genus. An overview of the copy number and location within the C. canephora genome of four TEs is presented. These are tested for their use as molecular markers to unravel the evolutionary history of the Millotii Complex, a group of six wild coffee (Coffea) species native to Madagascar. Two TEs from the Gypsy superfamily successfully recovered some species boundaries and geographic structure among samples, whereas a TE from the Copia superfamily did not. Notably, species occurring in evergreen moist forests of eastern and southeastern Madagascar were divergent with respect to species in other habitats and regions. Our results suggest that the peak of transpositional activity of the Gypsy and Copia TEs occurred, respectively, before and after the speciation events of the tested Madagascan species. We conclude that the utilization of active TEs has considerable potential to unravel the evolutionary history and delimitation of closely related Coffea species. However, the selection of TE needs to be experimentally tested, since each element has its own evolutionary history. Different TEs with similar copy number in a given species can render different dendrograms; thus copy number is not a good selection criterion to attain phylogenetic resolution. PMID:26231981

  19. Elemental abundances and temperatures of quiescent solar active region cores from X-ray observations

    NASA Astrophysics Data System (ADS)

    Del Zanna, G.; Mason, H. E.

    2014-05-01

    A brief review of studies of elemental abundances and emission measures in quiescent solar active region cores is presented. Hinode EUV Imaging Spectrometer (EIS) observations of strong iron spectral lines have shown sharply peaked distributions around 3 MK. EIS observations of lines emitted by a range of elements have allowed good estimates of abundances relative to iron. However, X-ray observations are required to measure the plasma emission above 3 MK and the abundances of oxygen and neon. We revisit, using up-to-date atomic data, older X-ray observations obtained by a sounding rocket and by the Solar Maximum Mission (SMM) Flat Crystal Spectrometer (FCS). We find that the Fe/O and Fe/Ne ratios are normally increased by a factor of 3.2, compared to the photospheric values. Similar results are obtained from FCS observations of six quiescent active region cores. The FCS observations also indicate that the emission measure above 3 MK has a very steep negative slope, with very little plasma observed at 5 MK or above. Appendix A is available in electronic form at http://www.aanda.org

  20. Role of surface-active elements during keyhole-mode laser welding

    NASA Astrophysics Data System (ADS)

    Ribic, B.; Tsukamoto, S.; Rai, R.; DebRoy, T.

    2011-12-01

    During high power density laser welding of mild steel, the keyhole depth, liquid metal flow, weld geometry and weld integrity are affected by base-metal sulfur content and oxygen (O2) present in the atmosphere or shielding gas. The role of these surface-active elements during keyhole-mode laser welding of steels is not well understood. In order to better understand their effects, welding of mild steel specimens containing various concentrations of oxygen and sulfur are examined. In addition, a numerical model is used to evaluate the influence of the surface-active elements on heat transfer and fluid flow in keyhole-mode laser welding. Increase in base-metal sulfur concentration or O2 content of shielding gas results in decreased weld widths. Sulfur results in a negligible increase in penetration depth whereas the presence of O2 in shielding gas significantly affects the weld penetration. It has earlier been proposed that oxygen, if present in the shielding gas, can get introduced into the weld pool resulting in formation of carbon monoxide (CO) at the keyhole surface and additional pressure from CO can result in increased penetration. Numerical modelling has been used in this work to understand the effects of formation of CO on the keyhole and weld geometries.

  1. Three-element trap filter radiometer based on large active area silicon photodiodes.

    PubMed

    Salim, S G R; Anhalt, K; Taubert, D R; Hollandt, J

    2016-05-20

    This paper shows the opto-mechanical design of a new filter radiometer built at the Physikalisch-Technische Bundesanstalt, Germany, for the accurate determination of the thermodynamic temperature of high-temperature blackbodies. The filter radiometer is based on a three-element reflection-type trap detector that uses three large active area silicon photodiodes. Its spectral coverage and field of view are defined by a detachable narrow-band filter and a diamond-turned precision aperture, respectively. The temperature of the filter radiometer is stabilized using a water-streamed housing and is measured using a thin-film platinum thermometer placed onto the first photodiode element. The trap "mount" has been made as compact as possible, which, together with the large active area of the chosen photodiodes, allows a wide field of view. This work presents the design of the filter radiometer and discusses the criteria that have been considered in order for the filter radiometer to suit the application. PMID:27411121

  2. Identification of active transcriptional regulatory elements from GRO-seq data.

    PubMed

    Danko, Charles G; Hyland, Stephanie L; Core, Leighton J; Martins, Andre L; Waters, Colin T; Lee, Hyung Won; Cheung, Vivian G; Kraus, W Lee; Lis, John T; Siepel, Adam

    2015-05-01

    Modifications to the global run-on and sequencing (GRO-seq) protocol that enrich for 5'-capped RNAs can be used to reveal active transcriptional regulatory elements (TREs) with high accuracy. Here, we introduce discriminative regulatory-element detection from GRO-seq (dREG), a sensitive machine learning method that uses support vector regression to identify active TREs from GRO-seq data without requiring cap-based enrichment (https://github.com/Danko-Lab/dREG/). This approach allows TREs to be assayed together with gene expression levels and other transcriptional features in a single experiment. Predicted TREs are more enriched for several marks of transcriptional activation—including expression quantitative trait loci, disease-associated polymorphisms, acetylated histone 3 lysine 27 (H3K27ac) and transcription factor binding—than those identified by alternative functional assays. Using dREG, we surveyed TREs in eight human cell types and provide new insights into global patterns of TRE function. PMID:25799441

  3. The level of elements and antioxidant activity of commercial dietary supplement formulations based on edible mushrooms.

    PubMed

    Stilinović, Nebojša; Škrbić, Biljana; Živančev, Jelena; Mrmoš, Nataša; Pavlović, Nebojša; Vukmirović, Saša

    2014-12-01

    Commercial preparations of Cordyceps sinensis, Ganoderma lucidum and Coprinus comatus mushroom marketed as healthy food supplements in Serbia were analyzed by atomic absorption spectrometry with a graphite furnace (GFAAS) for their element content. Antioxidant activity potential and total phenolics of the same mushrooms were determined. The element content of mushroom samples was in the range of 0.130-0.360 mg kg(-1) for lead (Pb), <0.03-0.46 mg kg(-1) for arsenic (As), 0.09-0.39 mg kg(-1) for cadmium (Cd), 98.14-989.18 mg kg(-1) for iron (Fe), 0.10-101.32 mg kg(-1) for nickel (Ni), 5.06-26.50 mg kg(-1) for copper (Cu), 0.20-0.70 mg kg(-1) for cobalt (Co), 1.74-136.33 mg kg(-1) for chromium (Cr) and 2.19-21.54 mg kg(-1) for manganese (Mn). In the tests for measuring the antioxidant activity, the methanolic extract of C. sinensis showed the best properties. The same was seen for the analysis of selected phenolic compounds; C. sinensis was found to have the highest content. Commercial preparations of C. sinensis and C. comatus can be considered to be safe and suitable food supplements included in well-balanced diets. PMID:25294630

  4. Bisphenol A activates the Nrf1/2-antioxidant response element pathway in HEK 293 cells.

    PubMed

    Chepelev, Nikolai L; Enikanolaiye, Mutiat I; Chepelev, Leonid L; Almohaisen, Abdulrahman; Chen, Qixuan; Scoggan, Kylie A; Coughlan, Melanie C; Cao, Xu-Liang; Jin, Xiaolei; Willmore, William G

    2013-03-18

    Bisphenol A (BPA) is used in the production of polycarbonate plastics and epoxy resins for baby bottles, liners of canned food, and many other consumer products. Previously, BPA has been shown to reduce the activity of several antioxidant enzymes, which may contribute to oxidative stress. However, the underlying mechanism of the BPA-mediated effect upon antioxidant enzyme activity is unknown. Antioxidant and phase II metabolizing enzymes protect cells from oxidative stress and are transcriptionally activated by Nrf1 and Nrf2 factors through their cis-regulatory antioxidant response elements (AREs). In this work, we have assessed the effect of BPA on the Nrf1/2-ARE pathway in cultured human embryonic kidney (HEK) 293 cells. Surprisingly, glutathione and reactive oxygen species (ROS) assays revealed that BPA application created a more reduced intracellular environment in cultured HEK 293 cells. Furthermore, BPA increased the transactivation activity of ectopic Nrf1 and Nrf2 and increased the expression of ARE-target genes ho-1 and nqo1 at high (100-200 μM) BPA concentrations only. Our study suggests that BPA activates the Nrf1/2-ARE pathway at high (>10 μM) micromolar concentrations. PMID:23360430

  5. Analysis of solid-rocket effluents for aluminum, silicon, and other trace elements by neutron activation analysis

    NASA Technical Reports Server (NTRS)

    Furr, A. K.

    1974-01-01

    The sensitivity and reliability of neutron activation analysis in detecting trace elements in solid rocket effluents are discussed. Special attention was given to Al and Si contaminants. The construction and performance of a thermal column irradiation unit was reported.

  6. Melamine Alters Glutamatergic Synaptic Transmission of CA3-CA1 Synapses Presynaptically Through Autophagy Activation in the Rat Hippocampus.

    PubMed

    Zhang, Hui; Wang, Hui; Xiao, Xi; Zhang, Tao

    2016-01-01

    Melamine is an industrial chemical that can cause central nervous system disorders including excitotoxicity and cognitive impairment. Its illegal use in powdered baby formula was the focus of a milk scandal in China in 2008. One of our previous studies showed that melamine impaired glutamatergic transmission in rat hippocampal CA1 pyramidal cells. However, the underlying mechanism of action of melamine is unclear, and it is unknown if the CA3-CA1 pathway is directly involved. In the present study, a whole-cell patch-clamp technique was employed to investigate the effect of melamine on the hippocampal CA3-CA1 pathway in vitro. Both the evoked excitatory postsynaptic current (eEPSC) and the paired-pulse ratio (PPR) were recorded. Furthermore, we examined whether autophagy was involved in glutamatergic transmission alterations induced by melamine. Our data showed that melamine significantly increased the amplitude of eEPSCs in a dose-dependent manner. Inhibition of the N-methyl-D-aspartic acid receptor did not prevent the increase in eEPSC amplitude. In addition, the PPR was remarkably decreased by a melamine concentration of 5 × 10(-5) g/mL. It was found that autophagy could be activated by melamine and an autophagy inhibitor, 3-MA, prevented the melamine-induced increase in eEPSC amplitude. Overall, our results show that melamine presynaptically alters glutamatergic synaptic transmission of hippocampal CA3-CA1 synapses in vitro and this is likely associated with autophagy alteration. PMID:26530910

  7. A high frequency active voltage doubler in standard CMOS using offset-controlled comparators for inductive power transmission.

    PubMed

    Lee, Hyung-Min; Ghovanloo, Maysam

    2013-06-01

    In this paper, we present a fully integrated active voltage doubler in CMOS technology using offset-controlled high speed comparators for extending the range of inductive power transmission to implantable microelectronic devices (IMD) and radio-frequency identification (RFID) tags. This active voltage doubler provides considerably higher power conversion efficiency (PCE) and lower dropout voltage compared to its passive counterpart and requires lower input voltage than active rectifiers, leading to reliable and efficient operation with weakly coupled inductive links. The offset-controlled functions in the comparators compensate for turn-on and turn-off delays to not only maximize the forward charging current to the load but also minimize the back current, optimizing PCE in the high frequency (HF) band. We fabricated the active voltage doubler in a 0.5-μm 3M2P std . CMOS process, occupying 0.144 mm(2) of chip area. With 1.46 V peak AC input at 13.56 MHz, the active voltage doubler provides 2.4 V DC output across a 1 kΩ load, achieving the highest PCE = 79% ever reported at this frequency. In addition, the built-in start-up circuit ensures a reliable operation at lower voltages. PMID:23853321

  8. A High Frequency Active Voltage Doubler in Standard CMOS Using Offset-Controlled Comparators for Inductive Power Transmission

    PubMed Central

    Lee, Hyung-Min; Ghovanloo, Maysam

    2014-01-01

    In this paper, we present a fully integrated active voltage doubler in CMOS technology using offset-controlled high speed comparators for extending the range of inductive power transmission to implantable microelectronic devices (IMD) and radio-frequency identification (RFID) tags. This active voltage doubler provides considerably higher power conversion efficiency (PCE) and lower dropout voltage compared to its passive counterpart and requires lower input voltage than active rectifiers, leading to reliable and efficient operation with weakly coupled inductive links. The offset-controlled functions in the comparators compensate for turn-on and turn-off delays to not only maximize the forward charging current to the load but also minimize the back current, optimizing PCE in the high frequency (HF) band. We fabricated the active voltage doubler in a 0.5-μm 3M2P std. CMOS process, occupying 0.144 mm2 of chip area. With 1.46 V peak AC input at 13.56 MHz, the active voltage doubler provides 2.4 V DC output across a 1 kΩ load, achieving the highest PCE = 79% ever reported at this frequency. In addition, the built-in start-up circuit ensures a reliable operation at lower voltages. PMID:23853321

  9. Effects of Deltamethrin on crayfish motor axon activity and neuromuscular transmission.

    PubMed

    Meng, Linlin; Meyer, Pierre-Francois N R; Leary, Meghan L; Mohammed, Yussef F; Ferber, Shelbi D; Lin, Jen-Wei

    2016-03-23

    Deltamethrin (DM) is a widely used pesticide known to target sodium channels. Although this compound has been studied extensively at molecular and behavioral levels, the detailed action of DM on cellular and synaptic function is less well documented. In this report, we show that DM at nanomolar concentrations can silence tonic motor output of the crayfish ventral superficial flexor (VSF) within ∼10 min. Action potential (AP) amplitude was consistently reduced before silencing occurred, whereas AP duration and AP firing frequency did not change. In some synapses EPSP amplitude and synaptic delay were modified by DM, but the direction of change was not consistent. In order to better understand these diverse effects, intracellular recordings from motor axons of the crayfish opener were used for a detailed analysis. DM caused an initial, slow depolarization of resting membrane potential (Vm), which was accompanied by reduced AP amplitude but not AP duration. Resting Vm then underwent a step depolarization of ∼20 mV, which we propose corresponds to the onset of the depolarization block. In addition, DM shifted the AP initiation site in some opener axons during prolonged firing. This shift occurred concomitantly with a reduction in synaptic delay. A similar reduction in synaptic delay was also detected at some VSF axons, and can be attributed to the same mechanism. Results reported here suggest that DM at low concentrations result in: (i) depolarization block of motor axons before changes in network output can be detected, (ii) variable effects on synaptic transmission, with this variability presumably due to the diverse morphology and excitability of motor axons. PMID:26861201

  10. Quantitative comparison of cis-regulatory element (CRE) activities in transgenic Drosophila melanogaster.

    PubMed

    Rogers, William A; Williams, Thomas M

    2011-01-01

    Gene expression patterns are specified by cis-regulatory element (CRE) sequences, which are also called enhancers or cis-regulatory modules. A typical CRE possesses an arrangement of binding sites for several transcription factor proteins that confer a regulatory logic specifying when, where, and at what level the regulated gene(s) is expressed. The full set of CREs within an animal genome encodes the organism's program for development, and empirical as well as theoretical studies indicate that mutations in CREs played a prominent role in morphological evolution. Moreover, human genome wide association studies indicate that genetic variation in CREs contribute substantially to phenotypic variation. Thus, understanding regulatory logic and how mutations affect such logic is a central goal of genetics. Reporter transgenes provide a powerful method to study the in vivo function of CREs. Here a known or suspected CRE sequence is coupled to heterologous promoter and coding sequences for a reporter gene encoding an easily observable protein product. When a reporter transgene is inserted into a host organism, the CRE's activity becomes visible in the form of the encoded reporter protein. P-element mediated transgenesis in the fruit fly species Drosophila (D.) melanogaster has been used for decades to introduce reporter transgenes into this model organism, though the genomic placement of transgenes is random. Hence, reporter gene activity is strongly influenced by the local chromatin and gene environment, limiting CRE comparisons to being qualitative. In recent years, the phiC31 based integration system was adapted for use in D. melanogaster to insert transgenes into specific genome landing sites. This capability has made the quantitative measurement of gene and, relevant here, CRE activity feasible. The production of transgenic fruit flies can be outsourced, including phiC31-based integration, eliminating the need to purchase expensive equipment and/or have proficiency at

  11. Activity of a Py-Im Polyamide Targeted to the Estrogen Response Element

    PubMed Central

    Nickols, Nicholas G.; Szablowski, Jerzy O.; Hargrove, Amanda E.; Li, Benjamin C.; Raskatov, Jevgenij A.; Dervan, Peter B.

    2013-01-01

    Pyrrole-imidazole (Py-Im) polyamides are a class of programmable DNA minor groove binders capable of modulating the activity of DNA-binding proteins and affecting changes in gene expression. Estrogen Receptor Alpha (ERα) is a ligand-activated hormone receptor that binds as a homodimer to estrogen response elements (EREs) and is a driving oncogene in a majority of breast cancers. We tested a selection of structurally similar Py-Im polyamides with differing DNA sequence specificity for activity against 17β-estadiol (E2) induced transcription and cytotoxicity in ERα positive, E2 stimulated T47D-KBLUC cells, which express luciferase under ERα control. The most active polyamide targeted the sequence: 5’-WGGWCW-3’ (W = A or T), which is the canonical ERE-half site. Whole transcriptome analysis using RNA-Seq revealed that treatment of E2-stimulated breast cancer cells with this polyamide reduced the effects of E2 on the majority of those most strongly affected by E2, but had much less effect on the majority of E2 induced transcripts. In vivo, this polyamide circulated at detectable levels following subcutaneous injection and reduced levels of ER-driven luciferase expression in xenografted tumors in mice after subcutaneous compound administration without significant host toxicity. PMID:23443804

  12. Effects of heavy metal and other elemental additives to activated sludge on growth of Eisenia foetida

    SciTech Connect

    Hartenstein, R.; Neuhauser, E.F.; Narahara, A.

    1981-09-01

    The approximate level at which added concentrations of certain elements would cause an activated sludge to induce a toxic effect upon the growth of Eisenia foetida was determined. During 43 trials on sludge samples obtained throughout 1 year of study, earthworms grew from 3 to 10 mg live wt at hatching to 792 mg +- 18% (mean +- C.V.) in 8 weeks, when sludge was 24/sup 0/C and contained no additives. None of several elements commonly used in microbial growth media enhanced the growth rate of the earthworm. At salt concentrations up to about 6.6% on a dry wt basis, none of six anions tested was in and of itself toxic, while five of 15 cations - Co, Hg, Cu, Ni, and Cd - appeared specifically to inhibit growth rate or cause death. Manganese, Cr, and Pb were innocuous even at the highest levels of application - 22,000, 46,000, and 52,000 mg/kg, respectively. Neither the anionic nor cationic component of certain salts, such as NaCl or NH/sub 4/Cl, could be said to inhibit growth, which occurred only at high concentrations of these salts (about 3.3 and/or 6.6%). Below 7 mmho/cm, toxicity could not be correlated with electrolytic conductance, though higher values may help to explain the nonspecific growth inhibitory effects of salts like NaCl and KCl. Nor could toxicity ever be ascribed to hydrogen ion activity, since sludge pH was not altered even at the highest salt dose. It is concluded that except under very extreme conditions, the levels of heavy metals and salts generally found in activated sludges will not have an adverse affect on the growth of E. foetida.

  13. Immune-Based Approaches to the Prevention of Mother-to-child-Transmission of HIV-1: Active and Passive Immunization

    PubMed Central

    Lohman-Payne, Barb; Slyker, Jennifer; Rowland-Jones, Sarah L.

    2010-01-01

    Synopsis Despite more than two decades of research, an effective vaccine that can prevent HIV-1 infection in populations exposed to the virus remains elusive. In the pursuit of an HIV-1 vaccine, does prevention of exposure to maternal HIV-1 in utero, at birth or in early life through breast-milk require special consideration? In this article we will review what is known about the immune mechanisms of susceptibility and resistance to mother-to-child transmission (MTCT) of HIV-1 and will summarise studies that have used passive or active immunisation strategies to interrupt -MTCT of HIV-1. We will also describe potentially modifiable infectious co-factors that may enhance transmission and/or disease progression (especially in the developing world). Ultimately an effective prophylactic vaccine against HIV-1 infection will need to be deployed as part of the Extended Programme of Immunisation (EPI) recommended by the World Health Organisation (WHO) for use in developing countries, so it is important to understand how the infant immune system responds to HIV-1 antigens, both in natural infection and presented by candidate vaccines. PMID:21078451

  14. Nicotinic Transmission onto Layer 6 Cortical Neurons Relies on Synaptic Activation of Non-α7 Receptors.

    PubMed

    Hay, Y Audrey; Lambolez, Bertrand; Tricoire, Ludovic

    2016-06-01

    Nicotinic excitation in neocortex is mediated by low-affinity α7 receptors and by high-affinity α4β2 receptors. There is evidence that α7 receptors are synaptic, but it is unclear whether high-affinity receptors are activated by volume transmission or synaptic transmission. To address this issue, we characterized responses of excitatory layer 6 (L6) neurons to optogenetic release of acetylcholine (ACh) in cortical slices. L6 responses consisted in a slowly decaying α4β2 current and were devoid of α7 component. Evidence that these responses were mediated by synapses was 4-fold. 1) Channelrhodopsin-positive cholinergic varicosities made close appositions onto responsive neurons. 2) Inhibition of ACh degradation failed to alter onset kinetics and amplitude of currents. 3) Quasi-saturation of α4β2 receptors occurred upon ACh release. 4) Response kinetics were unchanged in low release probability conditions. Train stimulations increased amplitude and decay time of responses and these effects appeared to involve recruitment of extrasynaptic receptors. Finally, we found that the α5 subunit, known to be associated with α4β2 in L6, regulates short-term plasticity at L6 synapses. Our results are consistent with previous anatomical observations of widespread cholinergic synapses and suggest that a significant proportion of these small synapses operate via high-affinity nicotinic receptors. PMID:25934969

  15. Fish Swimming: Patternsin the Mechanical Energy Generation, Transmission and Dissipation from Muscle Activation to Body Movement

    NASA Astrophysics Data System (ADS)

    Zhang, W.; Yu, Y. L.; Tong, B. G.

    2011-09-01

    The power consumption of the undulatory fish swimming is produced by active muscles. The mechanical energy generated by stimulated muscles is dissipated partly by the passive tissues of fish while it is being transmitted to the fluid medium. Furthermore, the effective energy, propelling fish movement, is a part of that delivered by the fish body. The process depends on the interactions of the active muscles, the passive tissues, and the water surrounding the fish body. In the previous works, the body-fluid interactions have been investigated widely, but it is rarely considered how the mechanical energy generates, transmits and dissipates in fish swimming. This paper addresses the regular patterns of energy transfer process from muscle activation to body movement for a cruising lamprey (LAMPREY), a kind of anguilliform swimmer. It is necessary to propose a global modelling of the kinematic chain, which is composed of active muscle force-moment model, fish-body dynamic model and hydrodynamic model in order. The present results show that there are traveling energy waves along the fish body from anterior to posterior, accompanied with energy storing and dissipating due to the viscoelastic property of internal tissues. This study is a preliminary research on the framework of kinematic chain coordination performance in fish swimming.

  16. Risk Transmission Indicator of Schistosomiasis Japonicum Considering Human Activities in Lake and Marshland Regions- A Case Study of Poyang Lake, Jiangxi Province, P.R. China

    NASA Astrophysics Data System (ADS)

    Marie, Tiphanie; Yesou, Herve; Huber, Claire; De Fraipont, Paul; Uribe, Carlos; Lacaux, Jean-Pierre; Lafaye, Murielle; Lai, Xijun; Desnos, Yves-Louis

    2013-01-01

    This paper present the method used to determine the areas where schistosomiasis transmission is the higher. A primary work was necessary to this study: identification of potential presence of schistosomiasis japonicum’s vector in Poyang lakeshore area (Jiangxi Province, P.R. China). Results obtained from its first work were crossing with the most risky human activities and with villages to elaborate a level of transmission risk. The first parameter determined concern fishing, which was identified like the most risky activity for schistosomiasis transmission, and fish traps were digitalized using a very high resolution ALOS data. The second parameter is about the risky areas for buffalo grazing, and vector potential presence areas were crossed with village proximity to determine the most risky areas for human transmission. The third parameter built is a level of risk for each village digitalized around Poyang Lake, taking into account the proximity and level of potential presence of vector’s areas.

  17. Putative cis-Regulatory Elements Associated with Heat Shock Genes Activated During Excystation of Cryptosporidium parvum

    PubMed Central

    Lara, Ana M.; Serrano, Myrna; Sheth, Nihar; Buck, Gregory

    2010-01-01

    Background Cryptosporidiosis is a ubiquitous infectious disease, caused by the protozoan parasites Cryptosporidium hominis and C. parvum, leading to acute, persistent and chronic diarrhea worldwide. Although the complications of this disease can be serious, even fatal, in immunocompromised patients of any age, they have also been found to lead to long term effects, including growth inhibition and impaired cognitive development, in infected immunocompetent children. The Cryptosporidium life cycle alternates between a dormant stage, the oocyst, and a highly replicative phase that includes both asexual vegetative stages as well as sexual stages, implying fine genetic regulatory mechanisms. The parasite is extremely difficult to study because it cannot be cultured in vitro and animal models are equally challenging. The recent publication of the genome sequence of C. hominis and C. parvum has, however, significantly advanced our understanding of the biology and pathogenesis of this parasite. Methodology/Principal Findings Herein, our goal was to identify cis-regulatory elements associated with heat shock response in Cryptosporidium using a combination of in silico and real time RT-PCR strategies. Analysis with Gibbs-Sampling algorithms of upstream non-translated regions of twelve genes annotated as heat shock proteins in the Cryptosporidium genome identified a highly conserved over-represented sequence motif in eleven of them. RT-PCR analyses, described herein and also by others, show that these eleven genes bearing the putative element are induced concurrent with excystation of parasite oocysts via heat shock. Conclusions/Significance Our analyses suggest that occurrences of a motif identified in the upstream regions of the Cryptosporidium heat shock genes represent parts of the transcriptional apparatus and function as stress response elements that activate expression of these genes during excystation, and possibly at other stages in the life cycle of the parasite

  18. Molluscan mobile elements similar to the vertebrate recombination-activating genes

    PubMed Central

    Panchin, Yuri; Moroz, Leonid L.

    2009-01-01

    Animal genomes contain ~20,000 genes. Additionally millions of genes for antigen receptors are generated in cells of the immune system from the sets of separate gene segments by a mechanism known as the V(D)J somatic recombination. The components of the V(D)J recombination system, Recombination-Activating Gene proteins (RAG1 and RAG2) and recombination signal sequence (RSS), are thought to have “entered” the vertebrate genome as a hypothetical “RAG transposon”. Recently discovered mobile elements have terminal inverted repeats (TIRs) similar to RSS and may encode proteins with a different degree of similarity to RAG1. We describe a novel N-RAG-TP transposon identified from the sea slug Aplysia californica that encodes a protein similar to the N-terminal part of RAG1 in vertebrates. This refines the “RAG transposon” hypothesis and allows us to propose a scenario for V(D)J recombination machinery evolution from a relic transposon related to the existing mobile elements N-RAG-TP, Chapaev and Transib. PMID:18313399

  19. Determination of trace elements by instrumental neutron activation analysis in Anatolian bentonitic clays

    NASA Astrophysics Data System (ADS)

    Güngör, N.; Tulun, T.; Alemdar, A.

    1998-08-01

    Instrumental Neutron Activation Analysis (INAA) was carried out for the determination of trace elements in non-swelling type bentonitic clays. Samples were irradiated in Triga Mark II type of reactor at the Nuclear Institute of Technical University of Istanbul. Irradiation was performed in two steps for "short and long lived" isotopes. The γ spectra of short lived isotopes were interpreted with respect to Al, Ca, Mg, Na, K, Ti, Mn, V qualitatively and that of long lived isotopes with respect to Sc, Cr, Br, Sb, Cs, La, Ce, Sm, Yb, Hf quantitatively. The relative richness of the trace elements (Al, Ti, Ca, Mg, Na, K) observed in the Sampo 90 program was obtained using Atomic Absorption technique by normalizing its value to that of sodium. The silicon content of samples was determined by gravimetry. The results indicated that Sample I contained relatively higher amount of REE, Sb, Ca and Na than Sample II. The amount of Sc, Cr and Br were about similar in both samples. Concentrations of La, Ce, Sm and Yb are higher than REE abundances found in all natural waters. These results suggest that Ca-bentonite samples are representative of primary deposition environment. In addition, the Sc content of both the samples indicates that Ca-bentonite deposits originated from continental crust. The relatively high amount of REE might bring about porosity problems in the use of Ca-bentonite in cement and concrete production.

  20. Finite element modeling of the cyclic wetting mechanism in the active part of wheat awns.

    PubMed

    Zickler, Gerald A; Ruffoni, Davide; Dunlop, John W C; Elbaum, Rivka; Weinkamer, Richard; Fratzl, Peter; Antretter, Thomas

    2012-12-01

    Many plant tissues and organs are capable of moving due to changes in the humidity of the environment, such as the opening of the seed capsule of the ice plant and the opening of the pine cone. These are fascinating examples for the materials engineer, as these tissues are non-living and move solely through the differential swelling of anisotropic tissues and in principle may serve as examples for the bio-inspired design of artificial actuators. In this paper, we model the microstructure of the wild wheat awn (Triticum turgidum ssp. dicoccoides) by finite elements, especially focusing on the specific microscopic features of the active part of the awn. Based on earlier experimental findings, cell walls are modeled as multilayered cylindrical tubes with alternating cellulose fiber orientation in successive layers. It is shown that swelling upon hydration of this system leads to the formation of gaps between the layers, which could act as valves, thus enabling the entry of water into the cell wall. This supports the hypothesis that this plywood-like arrangement of cellulose fibrils enhances the effect of ambient humidity by accelerated water or vapor diffusion along the gaps. The finite element model shows that a certain distribution of axially and tangentially oriented fibers is necessary to generate sufficient tensile stresses within the cell wall to open nanometer-sized gaps between cell wall layers. PMID:22791359

  1. Ambient temperature fatigue tests of elements of an actively cooled honeycomb sandwich structural panel

    NASA Technical Reports Server (NTRS)

    Sharpe, E. L.; Elber, W.

    1977-01-01

    Elements of an actively cooled structural panel for a hypersonic aircraft have been investigated for fatigue characteristics. The study involved a bonded honeycomb sandwich panel with d-shaped coolant tubes. The curved portion of these tubes was embedded in the honeycomb, and the flat portion was bonded or soldered to the inner surface of the outer skin. The elements examined were two plain skin specimens (aluminum alloy); two specimens with skins attached to manifolds and tubes (one specimen was bonded, the other soldered); and a specimen representative of a corner section of the complete cooled sandwich. Sinusoidal loads were applied to all specimens. The honeycomb sandwich specimen was loaded in both tension and compression; the other specimens were loaded in tension only. The cooling tubes were pressurized with oil throughout the fatigue tests. The most significant results of these tests follow: All specimens exceeded their design life of 20,000 cycles without damage. Crack growth rates obtained in the plain skin specimens were used to determine the crack growth characteristics of aluminum alloy. Cracks in skins either bonded or soldered to cooling tubes propagated past the tubes without penetration. The coolant tubes served as crack arresters and temporarily stopped crack growth when a crack reached a tube-skin interface. The honeycomb core demonstrated that it could contain leakage from a tube.

  2. Experimental study of active control of wave transmission through hollow cylindrical struts

    NASA Astrophysics Data System (ADS)

    Pelinescu, Ion; Balachandran, Balakumar

    2001-08-01

    Experimental investigations conducted into active control of longitudinal waves transmitted through a hollow cylindrical strut are presented in this article. Following along the lines of our previous work, an active strut of finite extent length, instrumented with sensors, piezoelectric, and magnetostrictive actuators, is studied in the frequency range of 10 Hz to 2 kHz. Single and multiple actuator arrangements are employed in open loop control investigations, and the effectiveness of the control effort in minimizing longitudinal harmonic disturbances transmitted through the strut is experimentally investigated. Initial efforts towards development of feedforward and feedback boundary control algorithms for reducing longitudinal vibratory loads in finite length cylinders is also presented. For the feedback controller development, the strut-actuator ensemble is modeled by using the one dimensional wave equation and the direct method of Liapunov is used. The feedforward control algorithm is based on the previous model of the active strut and relies on measurements of axial strains and accelerations at the strut ends. The influence of the boundary conditions and static forces applied to the strut are also investigated. The relevance of the current work to control of structure-borne helicopter cabin interior noise is also discussed.

  3. Transmission electron microscope observation of organic-inorganic hybrid thin active layers of light-emitting diodes

    NASA Astrophysics Data System (ADS)

    Jitsui, Yusuke; Ohtani, Naoki

    2012-10-01

    We performed transmission electron microscope (TEM) observation of organic-inorganic hybrid thin films fabricated by the sol-gel reaction and used as the active layers of organic light-emitting diodes. The cross-sectional TEM images show that the films consist of a triple-layer structure. To evaluate the composition of these layers, the distribution of atoms in them was measured by energy-dispersive X-ray fluorescence spectroscopy. As a result, most of the organic emissive material, poly(9,9-dioctyl-fluorene-co- N-4-butylphenyl-diphenylamine (TFB), was found to be distributed in the middle layer sandwiched by SiO and SiO2 layers. The surface SiO layer was fabricated due to the lack of oxygen. This means that the best sol-gel condition was changed due to the TFB doping; thus, the novel best condition should be found.

  4. Transmission electron microscope observation of organic-inorganic hybrid thin active layers of light-emitting diodes.

    PubMed

    Jitsui, Yusuke; Ohtani, Naoki

    2012-01-01

    We performed transmission electron microscope (TEM) observation of organic-inorganic hybrid thin films fabricated by the sol-gel reaction and used as the active layers of organic light-emitting diodes. The cross-sectional TEM images show that the films consist of a triple-layer structure. To evaluate the composition of these layers, the distribution of atoms in them was measured by energy-dispersive X-ray fluorescence spectroscopy. As a result, most of the organic emissive material, poly(9,9-dioctyl-fluorene-co-N-4-butylphenyl-diphenylamine (TFB), was found to be distributed in the middle layer sandwiched by SiO and SiO2 layers. The surface SiO layer was fabricated due to the lack of oxygen. This means that the best sol-gel condition was changed due to the TFB doping; thus, the novel best condition should be found. PMID:23095451

  5. Identical Location Transmission Electron Microscopy Imaging of Site-Selective Pt Nanocatalysts: Electrochemical Activation and Surface Disordering.

    PubMed

    Arán-Ais, Rosa M; Yu, Yingchao; Hovden, Robert; Solla-Gullón, Jose; Herrero, Enrique; Feliu, Juan M; Abruña, Héctor D

    2015-12-01

    We have employed identical location transmission electron microscopy (IL-TEM) to study changes in the shape and morphology of faceted Pt nanoparticles as a result of electrochemical cycling; a procedure typically employed for activating platinum surfaces. We find that the shape and morphology of the as-prepared hexagonal nanoparticles are rapidly degraded as a result of potential cycling up to +1.3 V. As few as 25 potential cycles are sufficient to cause significant degradation, and after about 500-1000 cycles the particles are dramatically degraded. We also see clear evidence of particle migration during potential cycling. These finding suggest that great care must be exercised in the use and study of shaped Pt nanoparticles (and related systems) as electrocatlysts, especially for the oxygen reduction reaction where high positive potentials are typically employed. PMID:26524187

  6. Linear Closed-form Solution and Finite-element Analysis of an Active Tensegrity Unit

    NASA Astrophysics Data System (ADS)

    Kmeť, Stanislav; Platko, Peter

    2012-11-01

    Results of the linear closed form solution of an active or adaptive tensegrity unit, as well as its numerical analysis using finite element method are presented in the paper. The shape of the unit is an octahedral cell with a square base and it is formed by thirteen members (four bottom and four top cables, four edge struts and one central strut). The central strut is designed as an actuator that allows for an adjustment of the shape of the unit which leads to changes of tensile forces in the cables. Due to the diagonal symmetry of the 3D tensegrity unit the closed-form analysis is based on the 2D solution of the equivalent planar biconvex cable system with one central strut under a vertical point load.

  7. Recent perspectives in solar physics - Elemental composition, coronal structure and magnetic fields, solar activity

    NASA Technical Reports Server (NTRS)

    Newkirk, G., Jr.

    1975-01-01

    Elemental abundances in the solar corona are studied. Abundances in the corona, solar wind and solar cosmic rays are compared to those in the photosphere. The variation in silicon and iron abundance in the solar wind as compared to helium is studied. The coronal small and large scale structure is investigated, emphasizing magnetic field activity and examining cosmic ray generation mechanisms. The corona is observed in the X-ray and EUV regions. The nature of coronal transients is discussed with emphasis on solar-wind modulation of galactic cosmic rays. A schematic plan view of the interplanetary magnetic field during sunspot minimum is given showing the presence of magnetic bubbles and their concentration in the region around 4-5 AU by a fast solar wind stream.

  8. Three-dimensional display utilizing a diffractive optical element and an active matrix liquid crystal display

    NASA Astrophysics Data System (ADS)

    Nordin, Gregory P.; Jones, Michael W.; Kulick, Jeffrey H.; Lindquist, Robert G.; Kowel, Stephen T.

    1996-12-01

    We describe the design, construction, and performance of the first real-time autostereoscopic 3D display based on the partial pixel 3D display architecture. The primary optical components of the 3D display are an active-matrix liquid crystal display and a diffractive optical element (DOE). The display operates at video frame rates and is driven with a conventional VGA signal. 3D animations with horizontal motion parallax are readily viewable as sets of stereo images. Formation of the virtual viewing slits by diffraction from the partial pixel apertures is experimentally verified. The measured contrast and perceived brightness of the display are excellent, but there are minor flaws in image quality due to secondary images. The source of these images and how they may be eliminated is discussed. The effects of manufacturing-related systematic errors in the DOE are also analyzed.

  9. Remote Activation of Host Cell DNA Synthesis in Uninfected Cells Signaled by Infected Cells in Advance of Virus Transmission

    PubMed Central

    Schmidt, Nora; Hennig, Thomas; Serwa, Remigiusz A.; Marchetti, Magda

    2015-01-01

    ABSTRACT Viruses modulate cellular processes and metabolism in diverse ways, but these are almost universally studied in the infected cell itself. Here, we study spatial organization of DNA synthesis during multiround transmission of herpes simplex virus (HSV) using pulse-labeling with ethynyl nucleotides and cycloaddition of azide fluorophores. We report a hitherto unknown and unexpected outcome of virus-host interaction. Consistent with the current understanding of the single-step growth cycle, HSV suppresses host DNA synthesis and promotes viral DNA synthesis in spatially segregated compartments within the cell. In striking contrast, during progressive rounds of infection initiated at a single cell, we observe that infection induces a clear and pronounced stimulation of cellular DNA replication in remote uninfected cells. This induced DNA synthesis was observed in hundreds of uninfected cells at the extended border, outside the perimeter of the progressing infection. Moreover, using pulse-chase analysis, we show that this activation is maintained, resulting in a propagating wave of host DNA synthesis continually in advance of infection. As the virus reaches and infects these activated cells, host DNA synthesis is then shut off and replaced with virus DNA synthesis. Using nonpropagating viruses or conditioned medium, we demonstrate a paracrine effector of uninfected cell DNA synthesis in remote cells continually in advance of infection. These findings have significant implications, likely with broad applicability, for our understanding of the ways in which virus infection manipulates cell processes not only in the infected cell itself but also now in remote uninfected cells, as well as of mechanisms governing host DNA synthesis. IMPORTANCE We show that during infection initiated by a single particle with progressive cell-cell virus transmission (i.e., the normal situation), HSV induces host DNA synthesis in uninfected cells, mediated by a virus-induced paracrine

  10. Activation of antioxidant response element (ARE)-dependent genes by roasted coffee extracts.

    PubMed

    Yazheng, Liu; Kitts, David D

    2012-09-01

    Coffee beans contain numerous bioactive components that exhibit antioxidant capacity when assessed using both chemical, cell free, and biological, cell-based model systems. However, the mechanisms underlying the antioxidant effects of coffee in biological systems are not totally understood and in some cases vary considerably from results obtained with simpler in vitro chemical assays. In the present study, the physicochemical characteristics and antioxidant activity of roasted and non-roasted coffee extracts were investigated in both cell free (ORAC(FL)) and cell-based systems. A profile of antioxidant gene expression in cultured human colon adenocarcinoma Caco-2 cells treated with both roasted and non-roasted coffee extracts, respectively, was investigated using Real-Time polymerase chain reaction (PCR) array technology. Results demonstrated that the mechanisms of the antioxidant activity associated with coffee constituents assessed by the ORAC(FL) assay were different to those observed using an intracellular oxidation assay with Caco-2 cells. Moreover, roasted coffee (both light and dark roasted) extracts produced both increased- and decreased-expressions of numerous genes that are involved in the management of oxidative stress via the antioxidant defence system. The selective and specific positive induction of antioxidant response element (ARE)-dependent genes, including gastrointestinal glutathione peroxidase (GPX2), sulfiredoxin (SRXN1), thioredoxin reductase 1 (TXNRD1), peroxiredoxin 1 (PRDX1), peroxiredoxin 4 (PDRX4) and peroxiredoxin 6 (PDRX6) were identified with the activation of the endogenous antioxidant defence system in Caco-2 cells. PMID:22699814

  11. Prediction and Validation of Gene Regulatory Elements Activated During Retinoic Acid Induced Embryonic Stem Cell Differentiation.

    PubMed

    Simandi, Zoltan; Horvath, Attila; Nagy, Peter; Nagy, Laszlo

    2016-01-01

    Embryonic development is a multistep process involving activation and repression of many genes. Enhancer elements in the genome are known to contribute to tissue and cell-type specific regulation of gene expression during the cellular differentiation. Thus, their identification and further investigation is important in order to understand how cell fate is determined. Integration of gene expression data (e.g., microarray or RNA-seq) and results of chromatin immunoprecipitation (ChIP)-based genome-wide studies (ChIP-seq) allows large-scale identification of these regulatory regions. However, functional validation of cell-type specific enhancers requires further in vitro and in vivo experimental procedures. Here we describe how active enhancers can be identified and validated experimentally. This protocol provides a step-by-step workflow that includes: 1) identification of regulatory regions by ChIP-seq data analysis, 2) cloning and experimental validation of putative regulatory potential of the identified genomic sequences in a reporter assay, and 3) determination of enhancer activity in vivo by measuring enhancer RNA transcript level. The presented protocol is detailed enough to help anyone to set up this workflow in the lab. Importantly, the protocol can be easily adapted to and used in any cellular model system. PMID:27403939

  12. Coping with dehydration: sympathetic activation and regulation of glutamatergic transmission in the hypothalamic PVN.

    PubMed

    Bardgett, Megan E; Chen, Qing-Hui; Guo, Qing; Calderon, Alfredo S; Andrade, Mary Ann; Toney, Glenn M

    2014-06-01

    Autonomic and endocrine profiles of chronic hypertension and heart failure resemble those of acute dehydration. Importantly, all of these conditions are associated with exaggerated sympathetic nerve activity (SNA) driven by glutamatergic activation of the hypothalamic paraventricular nucleus (PVN). Here, studies sought to gain insight into mechanisms of disease by determining the role of PVN ionotropic glutamate receptors in supporting SNA and mean arterial pressure (MAP) during dehydration and by elucidating mechanisms regulating receptor activity. Blockade of PVN N-methyl-D-aspartate (NMDA) receptors reduced (P < 0.01) renal SNA and MAP in urethane-chloralose-anesthetized dehydrated (DH) (48 h water deprivation) rats, but had no effect in euhydrated (EH) controls. Blockade of PVN α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors had no effect in either group. NMDA in PVN caused dose-dependent increases of renal SNA and MAP in both groups, but the maximum agonist evoked response (Emax) of the renal SNA response was greater (P < 0.05) in DH rats. The latter was not explained by increased PVN expression of NMDA receptor NR1 subunit protein, increased PVN neuronal excitability, or decreased brain water content. Interestingly, PVN injection of the pan-specific excitatory amino acid transporter (EAAT) inhibitor DL-threo-β-benzyloxyaspartic acid produced smaller sympathoexcitatory and pressor responses in DH rats, which was associated with reduced glial expression of EAAT2 in PVN. Like chronic hypertension and heart failure, dehydration increases excitatory NMDA receptor tone in PVN. Reduced glial-mediated glutamate uptake was identified as a key contributing factor. Defective glutamate uptake in PVN could therefore be an important, but as yet unexplored, mechanism driving sympathetic hyperactivity in chronic cardiovascular diseases. PMID:24671240

  13. Activity-dependent transmission and integration control the timescales of auditory processing at an inhibitory synapse.

    PubMed

    Ammer, Julian J; Siveke, Ida; Felmy, Felix

    2015-06-15

    To capture the context of sensory information, neural networks must process input signals across multiple timescales. In the auditory system, a prominent change in temporal processing takes place at an inhibitory GABAergic synapse in the dorsal nucleus of the lateral lemniscus (DNLL). At this synapse, inhibition outlasts the stimulus by tens of milliseconds, such that it suppresses responses to lagging sounds, and is therefore implicated in echo suppression. Here, we untangle the cellular basis of this inhibition. We demonstrate with in vivo whole-cell patch-clamp recordings in Mongolian gerbils that the duration of inhibition increases with sound intensity. Activity-dependent spillover and asynchronous release translate the high presynaptic firing rates found in vivo into a prolonged synaptic output in acute slice recordings. A key mechanism controlling the inhibitory time course is the passive integration of the hyperpolarizing inhibitory conductance. This prolongation depends on the synaptic conductance amplitude. Computational modeling shows that this prolongation is a general mechanism and relies on a non-linear effect caused by synaptic conductance saturation when approaching the GABA reversal potential. The resulting hyperpolarization generates an efficient activity-dependent suppression of action potentials without affecting the threshold or gain of the input-output function. Taken together, the GABAergic inhibition in the DNLL is adjusted to the physiologically relevant duration by passive integration of inhibition with activity-dependent synaptic kinetics. This change in processing timescale combined with the reciprocal connectivity between the DNLLs implements a mechanism to suppress the distracting localization cues of echoes and helps to localize the initial sound source reliably. PMID:26004766

  14. Effects of Physical Activity on Trace Elements and Depression Related Biomarkers in Children and Adolescents.

    PubMed

    Alghadir, Ahmad H; Gabr, Sami A; Al-Eisa, Einas

    2016-08-01

    Not much is known about the role of physical activity (PA), obesity related variables, and trace elements as potential risk factors affecting neurotransmitters in schoolchildren with depression. Our objective was to investigate the effect of physical activity (PA) on depressive symptoms in children and adolescents. Also, we aimed to study the association of demographic variables, serum levels of Copper (Cu), Zinc (Zn), serotonin, and salivary cortisol with depression in this population. One hundred and fifty school children (90 boys and 60 girls) aged 7-18 years were recruited for this study. All participants were evaluated for depression using CDI-score analysis. Their physical activity levels were checked using pre-validated questionnaires. The serum levels of Copper (Cu), Zinc (Zn), cortisol, and serotonin were estimated using atomic absorption, and immunoassay techniques. About 48.7 % of the study population had depressive symptoms (CDI-score; ≥13), and were classified into mild, moderate, and severe categories. Older children, especially girls, had higher levels of depression. Participants with moderate and severe depression had significantly lower physical activity, serotonin, and zinc levels, Zn/Cu ratios, and significantly higher copper and cortisol levels. Physically active boys showed significantly lower depressive CDI-scores and improvement in cortisol, serotonin, Cu, and Zn concentrations compared to girls of sedentary life style. CDI- scores correlated positively with BMI, cortisol and Cu, and negatively with PA, serotonin and Zn concentrations. BMI, cortisol, serotonin, Cu and Zn, could explain about 59.3-79 % of the depressive symptoms among schoolchildren, according to stepwise regression analysis. This was especially true in especially older girls. PA and an adequate balance in Zn and Cu levels, plays a positive role in improving CDI-depressive score, BMI, serotonin and cortisol levels among schoolchildren. PMID:26701336

  15. Trans3D: a free tool for dynamical visualization of EEG activity transmission in the brain.

    PubMed

    Blinowski, Grzegorz; Kamiński, Maciej; Wawer, Dariusz

    2014-08-01

    The problem of functional connectivity in the brain is in the focus of attention nowadays, since it is crucial for understanding information processing in the brain. A large repertoire of measures of connectivity have been devised, some of them being capable of estimating time-varying directed connectivity. Hence, there is a need for a dedicated software tool for visualizing the propagation of electrical activity in the brain. To this aim, the Trans3D application was developed. It is an open access tool based on widely available libraries and supporting both Windows XP/Vista/7(™), Linux and Mac environments. Trans3D can create animations of activity propagation between electrodes/sensors, which can be placed by the user on the scalp/cortex of a 3D model of the head. Various interactive graphic functions for manipulating and visualizing components of the 3D model and input data are available. An application of the Trans3D tool has helped to elucidate the dynamics of the phenomena of information processing in motor and cognitive tasks, which otherwise would have been very difficult to observe. Trans3D is available at: http://www.eeg.pl/. PMID:24967953

  16. Sustained impact of community-based physical activity interventions: key elements for success

    PubMed Central

    2013-01-01

    Background Compelling evidence supports the cost effectiveness and potential impact of physical activity on chronic disease prevention and health promotion. Quality of evidence is one piece, but certainly not the sole determinant of whether public health interventions, physical activity focused or otherwise, achieve their full potential for impact. Health promotion at both population and community levels must progress beyond health intervention models that isolate individuals from social, environmental, and political systems of influence. We offer a critical evaluation of lessons learned from two successful research initiatives to provide insights as to how health promotion research contributes to sustained impact. We highlight factors key to success including the theoretical and methodological integration of: i) a social ecological approach; ii) participatory action research (PAR) methods; and iii) an interdisciplinary team. Methods To identify and illustrate the key elements of our success we layered an evaluation of steps taken atop a review of relevant literature. Results In the school-based case study (Action Schools! BC), the success of our approach included early and sustained engagement with a broad cross-section of stakeholders, establishing partnerships across sectors and at different levels of government, and team members across multiple disciplines. In the neighbourhood built environment case study, the three domains guided our approach through study design and team development, and the integration of older adults’ perspectives into greenway design plans. In each case study we describe how elements of the domains serve as a guide for our work. Conclusion To sustain and maximize the impact of community-based public health interventions we propose the integration of elements from three domains of research that acknowledge the interplay between social, environmental and poilitical systems of influence. We emphasize that a number of key factors determine

  17. Active thermal lensing elements for mode matching optimization in optical systems

    NASA Astrophysics Data System (ADS)

    Fulda, Paul

    2014-03-01

    In interferometric gravitational wave detectors of the advanced era and beyond, the high laser powers used lead to the generation of thermal lenses in the optics. This can lead to a reduction in the coupling between the various optical cavities comprising the detector, thus reducing its overall sensitivity. We present here an active device which can be used to compensate for such thermal effects, as well as static mismatches between cavities. The device uses a 4 segmented heater to heat a transmissive optic, generating a spherical or astigmatic lens which can be used to compensate other thermal lenses within an optical system. We report on in-vacuum tests of the device, including an interferometric measurement of the wavefront distortions induced by the device, and measurements of the dynamic range and response time. The device was shown to have no observable detrimental effect on wavefront distortion, a focal power dynamic range of 0 to -40 mD, and a response time of the order 1000 s. Supported by NSF grant PHY-1205512.

  18. The epidermal growth factor receptor regulates cofilin activity and promotes transmissible gastroenteritis virus entry into intestinal epithelial cells

    PubMed Central

    Hu, Weiwei; Zhu, Liqi; Yang, Xing; Lin, Jian; Yang, Qian

    2016-01-01

    Transmissible gastroenteritis virus (TGEV), a coronavirus, causes severe diarrhea and high mortality in newborn piglets. The porcine intestinal epithelium is the target of TGEV infection, but the mechanisms that TGEV disrupts the actin cytoskeleton and invades the host epithelium remain largely unknown. We not only found that TGEV infection stimulates F-actin to gather at the cell membrane but the disruption of F-actin inhibits TGEV entry as well. Cofilin is involved in F-actin reorganization and TGEV entry. The TGEV spike protein is capable of binding with EGFR, activating the downstream phosphoinositide-3 kinase (PI3K), then causing the phosphorylation of cofilin and F-actin polymerization via Rac1/Cdc42 GTPases. Inhibition of EGFR and PI3K decreases the entry of TGEV. EGFR is also the upstream activator of mitogen-activated protein kinase (MAPK) signaling pathways that is involved in F-actin reorganization. Additionally, lipid rafts act as signal platforms for the EGFR-associated signaling cascade and correlate with the adhesion of TGEV. In conlusion, these results provide valuable data of the mechanisms which are responsible for the TGEV pathogenesis and may lead to the development of new methods about controlling TGEV. PMID:26933809

  19. Transmission blocking activity of Azadirachta indica and Guiera senegalensis extracts on the sporogonic development of Plasmodium falciparum field isolates in Anopheles coluzzii mosquitoes

    PubMed Central

    2014-01-01

    Background Targeting the stages of the malaria parasites responsible for transmission from the human host to the mosquito vector is a key pharmacological strategy for malaria control. Research efforts to identify compounds that are active against these stages have significantly increased in recent years. However, at present, only two drugs are available, namely primaquine and artesunate, which reportedly act on late stage gametocytes. Methods In this study, we assessed the antiplasmodial effects of 5 extracts obtained from the neem tree Azadirachta indica and Guiera senegalensis against the early vector stages of Plasmodium falciparum, using field isolates. In an ex vivo assay gametocytaemic blood was supplemented with the plant extracts and offered to Anopheles coluzzii females by membrane feeding. Transmission blocking activity was evaluated by assessing oocyst prevalence and density on the mosquito midguts. Results Initial screening of the 5 plant extracts at 250 ppm revealed transmission blocking activity in two neem preparations. Up to a concentration of 70 ppm the commercial extract NeemAzal® completely blocked transmission and at 60 ppm mosquitoes of 4 out of 5 replicate groups remained uninfected. Mosquitoes fed on the ethyl acetate phase of neem leaves at 250 ppm showed a reduction in oocyst prevalence of 59.0% (CI95 12.0 - 79.0; p < 10-4) and in oocyst density of 90.5% (CI95 86.0 - 93.5; p < 10-4 ), while the ethanol extract from the same plant part did not exhibit any activity. No evidence of transmission blocking activity was found using G. senegalensis ethyl acetate extract from stem galls. Conclusions The results of this study highlight the potential of antimalarial plants for the discovery of novel transmission blocking molecules, and open up the potential of developing standardized transmission blocking herbal formulations as malaria control tools to complement currently used antimalarial drugs and combination treatments. PMID:24735564

  20. Active control of sound transmission/radiation from elastic plates by vibration inputs. II - Experiments

    NASA Technical Reports Server (NTRS)

    Metcalf, V. L.; Fuller, C. R.; Silcox, R. J.; Brown, D. E.

    1992-01-01

    Actively controlled harmonic force inputs were applied experimentally to reduce the sound transmitted through an elastic circular plate. The control implementation used a time domain least mean square adaptive algorithm with two error sensors. The control forces were applied directly to the plate by point force vibration inputs, while the error information and performance were measured in the radiated acoustic field by microphones. Test cases were also performed in which the error sensors were accelerometers mounted on the plate. When accelerometers were used as error sensors, the controller performance was degraded; leading to the conclusion that minimizing plate motion does not necessarily lead to an associated decrease in radiated sound levels. In contrast, the results show excellent attenuation of the transmitted sound field when microphone error sensors were used. This result was consistent over a range of frequencies. In addition, the experimental results are compared to previously derived analytical results and the effect of using a point or global minimization scheme is discussed.

  1. Active control of sound transmission/radiation from elastic plates by vibration inputs. I - Analysis

    NASA Technical Reports Server (NTRS)

    Fuller, C. R.

    1990-01-01

    Active control of sound radiation from vibrating plates by oscillating forces applied directly to the structure is analytically studied. The model consists of a plane acoustic wave incident on a clamped elastic circular thin plate. Control is achieved by point forces, and quadratic optimization is used to calculate the optimal control gains necessary to minimize a cost function proportional to the radiated acoustic power (the transmitted field). The results show that global attenuation of broadband radiated sound levels for low to mid-range frequencies can be achieved with one or two control forces, irrespective of whether the system is on or off resonance. The efficiency of the control strategy is demonstrated to be related to the nature of the coupling between the plate modes of response and the radiated field.

  2. Enhancer and promoter elements directing activation and glucocorticoid repression of the. cap alpha. /sub 1/-fetoprotein gene in hepatocytes

    SciTech Connect

    Guertin, M.; La Rue, H.; Bernier, D.; Wrange, O.; Chevrette, M.; Gingras, M.C.; Belanger, L.

    1988-04-01

    Mutations were introduced in 7 kilobases of 5'-flanking rat ..cap alpha../sub 1/-fetoprotein (AFP) genomic DNA, linked to the chloramphenicol acetyltransferase gene. AFP promoter activity and its repression by a glucocorticoid hormone were assessed by stable and transient expression assays. Stable transfection assays were more sensitive and accurate than transient expression assays in a Morris 7777 rat hepatoma recipient (Hepa7.6), selected for its strong AFP repression by dexamethasone. The segment of DNA encompassing a hepatocyte-constitutive chromatin DNase I-hypersensitive site at -3.7 kilobases and a liver developmental stage-specific site at -2.5 kilobases contains interacting enhancer elements sufficient for high AFP promoter activity in Hepa7.6 or HepG2 cells. Deletions and point mutations define an upstream promoter domain of AFP gene activation, operating with at least three distinct promoter-activating elements, PEI at -65 base pairs, PEII at -120 base pairs, and DE at -160 base pairs. PEI and PEII share homologies with albumin promoter sequences, PEII is a near-consensus nuclear factor I recognition sequence, and DE overlaps a glucocorticoid receptor recognition sequence. An element conferring glucocorticoid repression of AFP gene activity is located in the upstream AFP promoter domain. Receptor-binding assays indicate that this element is the glucocorticoid receptor recognition sequence which overlaps with promoter-activating element DE.

  3. Association of Composite IS26-sul3 Elements with Highly Transmissible IncI1 Plasmids in Extended-Spectrum-β-Lactamase-Producing Escherichia coli Clones from Humans▿

    PubMed Central

    Curiao, Tânia; Cantón, Rafael; Garcillán-Barcia, M. Pilar; de la Cruz, Fernando; Baquero, Fernando; Coque, Teresa M.

    2011-01-01

    The association of an IS440-sul3 platform with Tn21 class 1 integrons carried by IncI1 plasmids encoding extended-spectrum β-lactamases (ESBLs; mainly SHV-12 and CTX-M-14) among worldwide Escherichia coli clones of phylogroups A (ST10, ST23, and ST46), B1 (ST155, ST351, and ST359), and D/B2 (ST131) is reported. An in silico comparative analysis of sul3 elements available in the GenBank database shows the evolution of sul3 platforms by hosting different transposable elements facilitating the potential genesis of IS26 composite transposons and further insertion element-mediated promoted arrangements. PMID:21343460

  4. Dendritic morphology, synaptic transmission, and activity of mature granule cells born following pilocarpine-induced status epilepticus in the rat

    PubMed Central

    Gao, Fei; Song, Xueying; Zhu, Dexiao; Wang, Xiaochen; Hao, Aijun; Nadler, J. Victor; Zhan, Ren-Zhi

    2015-01-01

    To understand the potential role of enhanced hippocampal neurogenesis after pilocarpine-induced status epilepticus (SE) in the development of epilepsy, we quantitatively analyzed the geometry of apical dendrites, synaptic transmission, and activation levels of normotopically distributed mature newborn granule cells in the rat. SE in male Sprague-Dawley rats (between 6 and 7 weeks old) lasting for more than 2 h was induced by an intraperitoneal injection of pilocarpine. The complexity, spine density, miniature post-synaptic currents, and activity-regulated cytoskeleton-associated protein (Arc) expression of granule cells born 5 days after SE were studied between 10 and 17 weeks after CAG-GFP retroviral vector-mediated labeling. Mature granule cells born after SE had dendritic complexity similar to that of granule cells born naturally, but with denser mushroom-like spines in dendritic segments located in the outer molecular layer. Miniature inhibitory post-synaptic currents (mIPSCs) were similar between the controls and rats subjected to SE; however, smaller miniature excitatory post-synaptic current (mEPSC) amplitude with a trend toward less frequent was found in mature granule cells born after SE. After maturation, granule cells born after SE did not show denser Arc expression in the resting condition or 2 h after being activated by pentylenetetrazol-induced transient seizure activity than vicinal GFP-unlabeled granule cells. Thus our results suggest that normotopic granule cells born after pilocarpine-induced SE are no more active when mature than age-matched, naturally born granule cells. PMID:26500490

  5. De novo DNA demethylation and noncoding transcription define active intergenic regulatory elements.

    PubMed

    Schlesinger, Felix; Smith, Andrew D; Gingeras, Thomas R; Hannon, Gregory J; Hodges, Emily

    2013-10-01

    Deep sequencing of mammalian DNA methylomes has uncovered a previously unpredicted number of discrete hypomethylated regions in intergenic space (iHMRs). Here, we combined whole-genome bisulfite sequencing data with extensive gene expression and chromatin-state data to define functional classes of iHMRs, and to reconstruct the dynamics of their establishment in a developmental setting. Comparing HMR profiles in embryonic stem and primary blood cells, we show that iHMRs mark an exclusive subset of active DNase hypersensitive sites (DHS), and that both developmentally constitutive and cell-type-specific iHMRs display chromatin states typical of distinct regulatory elements. We also observe that iHMR changes are more predictive of nearby gene activity than the promoter HMR itself, and that expression of noncoding RNAs within the iHMR accompanies full activation and complete demethylation of mature B cell enhancers. Conserved sequence features corresponding to iHMR transcript start sites, including a discernible TATA motif, suggest a conserved, functional role for transcription in these regions. Similarly, we explored both primate-specific and human population variation at iHMRs, finding that while enhancer iHMRs are more variable in sequence and methylation status than any other functional class, conservation of the TATA box is highly predictive of iHMR maintenance, reflecting the impact of sequence plasticity and transcriptional signals on iHMR establishment. Overall, our analysis allowed us to construct a three-step timeline in which (1) intergenic DHS are pre-established in the stem cell, (2) partial demethylation of blood-specific intergenic DHSs occurs in blood progenitors, and (3) complete iHMR formation and transcription coincide with enhancer activation in lymphoid-specified cells. PMID:23811145

  6. Isoniazid suppresses antioxidant response element activities and impairs adipogenesis in mouse and human preadipocytes

    SciTech Connect

    Chen, Yanyan; Xue, Peng; Hou, Yongyong; Zhang, Hao; Zheng, Hongzhi; Zhou, Tong; Qu, Weidong; Teng, Weiping; Zhang, Qiang; Andersen, Melvin E.; Pi, Jingbo

    2013-12-15

    Transcriptional signaling through the antioxidant response element (ARE), orchestrated by the Nuclear factor E2-related factor 2 (Nrf2), is a major cellular defense mechanism against oxidative or electrophilic stress. Here, we reported that isoniazid (INH), a widely used antitubercular drug, displays a substantial inhibitory property against ARE activities in diverse mouse and human cells. In 3T3-L1 preadipocytes, INH concentration-dependently suppressed the ARE-luciferase reporter activity and mRNA expression of various ARE-dependent antioxidant genes under basal and oxidative stressed conditions. In keeping with our previous findings that Nrf2-ARE plays a critical role in adipogenesis by regulating expression of CCAAT/enhancer-binding protein β (C/EBPβ) and peroxisome proliferator-activated receptor γ (PPARγ), suppression of ARE signaling by INH hampered adipogenic differentiation of 3T3-L1 cells and human adipose-derived stem cells (ADSCs). Following adipogenesis induced by hormonal cocktails, INH-treated 3T3-L1 cells and ADSCs displayed significantly reduced levels of lipid accumulation and attenuated expression of C/EBPα and PPARγ. Time-course studies in 3T3-L1 cells revealed that inhibition of adipogenesis by INH occurred in the early stage of terminal adipogenic differentiation, where reduced expression of C/EBPβ and C/EBPδ was observed. To our knowledge, the present study is the first to demonstrate that INH suppresses ARE signaling and interrupts with the transcriptional network of adipogenesis, leading to impaired adipogenic differentiation. The inhibition of ARE signaling may be a potential underlying mechanism by which INH attenuates cellular antioxidant response contributing to various complications. - Highlights: • Isoniazid suppresses ARE-mediated transcriptional activity. • Isoniazid inhibits adipogenesis in preadipocytes. • Isoniazid suppresses adipogenic gene expression during adipogenesis.

  7. De novo DNA demethylation and noncoding transcription define active intergenic regulatory elements

    PubMed Central

    Schlesinger, Felix; Smith, Andrew D.; Gingeras, Thomas R.; Hannon, Gregory J.; Hodges, Emily

    2013-01-01

    Deep sequencing of mammalian DNA methylomes has uncovered a previously unpredicted number of discrete hypomethylated regions in intergenic space (iHMRs). Here, we combined whole-genome bisulfite sequencing data with extensive gene expression and chromatin-state data to define functional classes of iHMRs, and to reconstruct the dynamics of their establishment in a developmental setting. Comparing HMR profiles in embryonic stem and primary blood cells, we show that iHMRs mark an exclusive subset of active DNase hypersensitive sites (DHS), and that both developmentally constitutive and cell-type-specific iHMRs display chromatin states typical of distinct regulatory elements. We also observe that iHMR changes are more predictive of nearby gene activity than the promoter HMR itself, and that expression of noncoding RNAs within the iHMR accompanies full activation and complete demethylation of mature B cell enhancers. Conserved sequence features corresponding to iHMR transcript start sites, including a discernible TATA motif, suggest a conserved, functional role for transcription in these regions. Similarly, we explored both primate-specific and human population variation at iHMRs, finding that while enhancer iHMRs are more variable in sequence and methylation status than any other functional class, conservation of the TATA box is highly predictive of iHMR maintenance, reflecting the impact of sequence plasticity and transcriptional signals on iHMR establishment. Overall, our analysis allowed us to construct a three-step timeline in which (1) intergenic DHS are pre-established in the stem cell, (2) partial demethylation of blood-specific intergenic DHSs occurs in blood progenitors, and (3) complete iHMR formation and transcription coincide with enhancer activation in lymphoid-specified cells. PMID:23811145

  8. Ascaris and hookworm transmission in preschool children in rural Panama: role of subsistence agricultural activities.

    PubMed

    Krause, Rachel J; Koski, Kristine G; Pons, Emérita; Sinisterra, Odalis; Scott, Marilyn E

    2016-07-01

    This longitudinal study explored whether aspects of subsistence agriculture were associated with presence and intensity of Ascaris and hookworm in preschool children in rural Panama. Questionnaires were used to collect data on household socio-demographics, child exposure to agriculture and household agricultural practices. Stool samples were collected from children (6 months-5 years) at 3 time points, with albendazole administered after each to clear infections, resulting in 1 baseline and 2 reinfection measures. A novel Agricultural Activity Index (AAI) was developed using principal components analysis to measure the intensity of household agricultural practices. Zero-inflated negative binomial regression models revealed baseline hookworm egg counts were higher if children went to the agricultural plot and if the plot was smaller. Baseline and reinfection Ascaris egg counts were higher if children went to the plot and households had higher AAI, and higher at baseline if the plot was smaller. Caregiver time in the plot was negatively associated with baseline Ascaris egg counts, but positively associated with baseline hookworm and Ascaris reinfection egg counts. Children who spent more time playing around the home were less likely to be infected with Ascaris at baseline. We conclude that preschool child exposure to subsistence agriculture increased Ascaris and hookworm intensity. PMID:27000494

  9. Neutron activation analysis for the determination of trace elements in biological materials.

    PubMed

    Versieck, J

    1994-01-01

    Neutron activation analysis, in both its radiochemical and instrumental forms, is a precious technique for the determination of trace elements in biological materials. Probably its most important advantage is its relative freedom from errors resulting from contamination of the samples. Invaluable characteristics are also its excellent sensitivity, outstanding selectivity, and remarkable multielement capability. It is, however, necessary to warn against uncritical expectations. This is best illustrated by the seriously inconsistent results obtained in several laboratories. Because of the necessity to have access to a nuclear research reactor, the stringent safety rules to be observed, the rather high costs of the analyses, the relatively low sample throughput, and the sometimes long delay between the taking of a sample and the obtaining the final result, the use of neutron activation analysis remained restricted to a few--essentially research--laboratories. It found its main application in solving arduous problems and in paving the way for other analytical techniques better suited to routine applications. PMID:7710855

  10. Experimental analysis of tablet properties for discrete element modeling of an active coating process.

    PubMed

    Just, Sarah; Toschkoff, Gregor; Funke, Adrian; Djuric, Dejan; Scharrer, Georg; Khinast, Johannes; Knop, Klaus; Kleinebudde, Peter

    2013-03-01

    Coating of solid dosage forms is an important unit operation in the pharmaceutical industry. In recent years, numerical simulations of drug manufacturing processes have been gaining interest as process analytical technology tools. The discrete element method (DEM) in particular is suitable to model tablet-coating processes. For the development of accurate simulations, information on the material properties of the tablets is required. In this study, the mechanical parameters Young's modulus, coefficient of restitution (CoR), and coefficients of friction (CoF) of gastrointestinal therapeutic systems (GITS) and of active-coated GITS were measured experimentally. The dynamic angle of repose of these tablets in a drum coater was investigated to revise the CoF. The resulting values were used as input data in DEM simulations to compare simulation and experiment. A mean value of Young's modulus of 31.9 MPa was determined by the uniaxial compression test. The CoR was found to be 0.78. For both tablet-steel and tablet-tablet friction, active-coated GITS showed a higher CoF compared with GITS. According to the values of the dynamic angle of repose, the CoF was adjusted to obtain consistent tablet motion in the simulation and in the experiment. On the basis of this experimental characterization, mechanical parameters are integrated into DEM simulation programs to perform numerical analysis of coating processes. PMID:23354469

  11. Active photonic sensor communication cable for field application of optical data and power transmission

    NASA Astrophysics Data System (ADS)

    Suthau, Eike; Rieske, Ralf; Zerna, Thomas

    2014-10-01

    Omitting electrically conducting wires for sensor communication and power supply promises protection for sensor systems and monitored structures against lightning or high voltages, prevention of explosion hazards, and reduction of susceptibility to tampering. The ability to photonically power remote systems opens up the full range of electrical sensors. Power-over-fiber is an attractive option in electromagnetically sensitive environments, particularly for longterm, maintenance-free applications. It can deliver uninterrupted power sufficient for elaborate sensors, data processing or even actuators alongside continuous high speed data communication for remote sensor application. This paper proposes an active photonic sensor communication system, which combines the advantages of optical data links in terms of immunity to electromagnetic interference (EMI), high bandwidth, hardiness against tampering or eavesdropping, and low cable weight with the robustness one has come to expect from industrial or military electrical connectors. An application specific integrated circuit (ASIC) is presented that implements a closed-loop regulation of the sensor power supply to guarantee continuous, reliable data communications while maintaining a highly efficient, adaptive sensor supply scheme. It is demonstrated that the resulting novel photonic sensor communication cable can handle sensors and actuators differing orders of magnitude with respect to power consumption. The miniaturization of the electro-optical converters and driving electronics is as important to the presented development as the energy efficiency of the detached, optically powered sensor node. For this reason, a novel photonic packaging technology based on wafer-level assembly of the laser power converters by means of passive alignment will be disclosed in this paper.

  12. Sampling and major element chemistry of the recent (A.D. 1631-1944) Vesuvius activity

    USGS Publications Warehouse

    Belkin, H.E.; Kilburn, C.R.J.; de Vivo, B.

    1993-01-01

    Detailed sampling of the Vesuvius lavas erupted in the period A.D. 1631-1944 provides a suite of samples for comprehensive chemical analyses and related studies. Major elements (Si, Ti, Al, Fetotal, Mn, Mg, Ca, Na, K and P), volatile species (Cl, F, S, H2O+, H2O- and CO2), and ferrous iron (Fe2+) were determined for one hundred and forty-nine lavas and five tephra from the A.D. 1631-1944 Vesuvius activity. The lavas represent a relatively homogeneous suite with respect to SiO2, TiO2, FeOtotal, MnO and P2O5, but show systematic variations among MgO, K2O, Na2O, Al2O3 and CaO. The average SiO2 content is 48.0 wt.% and the rocks are classified as tephriphonolites according to their content of alkalis. All of the lavas are silica-undersaturated and are nepheline, leucite, and olivine normative. There is no systematic variation in major-element composition with time, over the period A.D. 1631-1944. The inter-eruption and intra-eruption compositional differences are the same magnitude. The lavas are highly porphyritic with clinopyroxene and leucite as the major phases. Fractionation effects are not reflected in the silica content of the lavas. The variability of MgO, K2O, Na2O, and CaO can be modelled as a relative depletion or accumulation of clinopyroxene. ?? 1993.

  13. Study of the generation characteristics of laser converters with dye-based wide-aperture solid--liquid active elements

    SciTech Connect

    Eremenko, A.S.; Zemskii, V.I.; Kolesnikov, Y.L.; Malinin, B.G.; Meshkovsky, I.K.; Savkin, N.P.; Stepanov, V.E.; Shildyaev, V.S.

    1986-11-01

    The lasing characteristics of an active element, consisting of a fine porous silicate matrix, has been studied. Molecules of a dye (rhodamine 6G) and an ethanol solution of the same dye were introduced into the cells. It has been shown that under conditions of large heat release (when thermooptical distortions begin to appear in the dye solutions), the solid--liquid element preserves the stability of its own lasing characteristics.

  14. [Hygienic study of an activated fibrous charcoal material as a sorbing filtering element for drinking water afterpurification].

    PubMed

    Prokopov, V A; Mironets, N V; Gakal, R K; Maktaz, E D; Dugan, A M; Teteneva, I A; Tarabarova, S B; Martyshchenko, N V; Nadvornaia, Zh D

    1993-01-01

    The results of complex toxicological and hygienic study showed that the quality of pipe water filtered through the activated carbonic fibrous material (ACFM) "Dnepr-F" forming a part of absorptive filtering element improved markedly. The content of organic substances decreased drastically as well as that of nitrates and iron. Microbiological indices did not suffer appreciable changes and were within permissible limits. The water filtered through the absorptive element with ACFM had no adverse influence on the organisms of warm-blooded animals. Proceeding from foregoing one can conclude that the "Dnepr-F" may be recommended as a part of absorptive filtering element for the final refinement of drinking water. PMID:8209499

  15. Atmospheric deposition of rare earth elements in Albania studied by the moss biomonitoring technique, neutron activation analysis and GIS technology.

    PubMed

    Allajbeu, Sh; Yushin, N S; Qarri, F; Duliu, O G; Lazo, P; Frontasyeva, M V

    2016-07-01

    Rare earth elements (REEs) are typically conservative elements that are scarcely derived from anthropogenic sources. The mobilization of REEs in the environment requires the monitoring of these elements in environmental matrices, in which they are present at trace level. The determination of 11 REEs in carpet-forming moss species (Hypnum cupressiforme) collected from 44 sampling sites over the whole territory of the country were done by using epithermal neutron activation analysis (ENAA) at IBR-2 fast pulsed reactor in Dubna. This paper is focused on REEs (lanthanides) and Sc. Fe as typical consistent element and Th that appeared good correlations between the elements of lanthanides are included in this paper. Th, Sc, and REEs were never previously determined in the air deposition of Albania. Descriptive statistics were used for data treatment using MINITAB 17 software package. The median values of the elements under investigation were compared with those of the neighboring countries such as Bulgaria, Macedonia, Romania, and Serbia, as well as Norway which is selected as a clean area. Geographical distribution maps of the elements over the sampled territory were constructed using geographic information system (GIS) technology. Geochemical behavior of REEs in moss samples has been studied by using the ternary diagram of Sc-La-Th, Spider diagrams and multivariate analysis. It was revealed that the accumulation of REEs in current mosses is associated with the wind-blowing metal-enriched soils that is pointed out as the main emitting factor of the elements under investigation. PMID:27044293

  16. Exosomes derived from HIV-1-infected cells contain trans-activation response element RNA.

    PubMed

    Narayanan, Aarthi; Iordanskiy, Sergey; Das, Ravi; Van Duyne, Rachel; Santos, Steven; Jaworski, Elizabeth; Guendel, Irene; Sampey, Gavin; Dalby, Elizabeth; Iglesias-Ussel, Maria; Popratiloff, Anastas; Hakami, Ramin; Kehn-Hall, Kylene; Young, Mary; Subra, Caroline; Gilbert, Caroline; Bailey, Charles; Romerio, Fabio; Kashanchi, Fatah

    2013-07-01

    Exosomes are nano-sized vesicles produced by healthy and virus-infected cells. Exosomes derived from infected cells have been shown to contain viral microRNAs (miRNAs). HIV-1 encodes its own miRNAs that regulate viral and host gene expression. The most abundant HIV-1-derived miRNA, first reported by us and later by others using deep sequencing, is the trans-activation response element (TAR) miRNA. In this study, we demonstrate the presence of TAR RNA in exosomes from cell culture supernatants of HIV-1-infected cells and patient sera. TAR miRNA was not in Ago2 complexes outside the exosomes but enclosed within the exosomes. We detected the host miRNA machinery proteins Dicer and Drosha in exosomes from infected cells. We report that transport of TAR RNA from the nucleus into exosomes is a CRM1 (chromosome region maintenance 1)-dependent active process. Prior exposure of naive cells to exosomes from infected cells increased susceptibility of the recipient cells to HIV-1 infection. Exosomal TAR RNA down-regulated apoptosis by lowering Bim and Cdk9 proteins in recipient cells. We found 10(4)-10(6) copies/ml TAR RNA in exosomes derived from infected culture supernatants and 10(3) copies/ml TAR RNA in the serum exosomes of highly active antiretroviral therapy-treated patients or long term nonprogressors. Taken together, our experiments demonstrated that HIV-1-infected cells produced exosomes that are uniquely characterized by their proteomic and RNA profiles that may contribute to disease pathology in AIDS. PMID:23661700

  17. Activation of Sterol Regulatory Element Binding Factors by Fenofibrate and Gemfibrozil Stimulates Myelination in Zebrafish

    PubMed Central

    Ashikawa, Yoshifumi; Nishimura, Yuhei; Okabe, Shiko; Sasagawa, Shota; Murakami, Soichiro; Yuge, Mizuki; Kawaguchi, Koki; Kawase, Reiko; Tanaka, Toshio

    2016-01-01

    Oligodendrocytes are major myelin-producing cells and play essential roles in the function of a healthy nervous system. However, they are also one of the most vulnerable neural cell types in the central nervous system (CNS), and myelin abnormalities in the CNS are found in a wide variety of neurological disorders, including multiple sclerosis, adrenoleukodystrophy, and schizophrenia. There is an urgent need to identify small molecular weight compounds that can stimulate myelination. In this study, we performed comparative transcriptome analysis to identify pharmacodynamic effects common to miconazole and clobetasol, which have been shown to stimulate myelination by mouse oligodendrocyte progenitor cells (OPCs). Of the genes differentially expressed in both miconazole- and clobetasol-treated mouse OPCs compared with untreated cells, we identified differentially expressed genes (DEGs) common to both drug treatments. Gene ontology analysis revealed that these DEGs are significantly associated with the sterol biosynthetic pathway, and further bioinformatics analysis suggested that sterol regulatory element binding factors (SREBFs) might be key upstream regulators of the DEGs. In silico screening of a public database for chemicals associated with SREBF activation identified fenofibrate, a peroxisome proliferator-activated receptor α (PPARα) agonist, as a drug that increases the expression of known SREBF targets, raising the possibility that fenofibrate may also stimulate myelination. To test this, we performed in vivo imaging of zebrafish expressing a fluorescent reporter protein under the control of the myelin basic protein (mbp) promoter. Treatment of zebrafish with fenofibrate significantly increased expression of the fluorescent reporter compared with untreated zebrafish. This increase was attenuated by co-treatment with fatostatin, a specific inhibitor of SREBFs, confirming that the fenofibrate effect was mediated via SREBFs. Furthermore, incubation of zebrafish

  18. Shingles Transmission

    MedlinePlus

    ... on Shingles Immunization Action Coalition Chickenpox Q&As Transmission Language: English Español (Spanish) Recommend on Facebook Tweet ... Prevention & Treatment Related Pages Preventing Varicella Zoster Virus Transmission in Healthcare Settings Related Links Medline Plus NIH ...

  19. Controlled trial comparing two types of enteral nutrition in treatment of active Crohn's disease: elemental versus polymeric diet.

    PubMed Central

    Rigaud, D; Cosnes, J; Le Quintrec, Y; René, E; Gendre, J P; Mignon, M

    1991-01-01

    To determine whether an elemental diet or a polymeric defined formula diet would be more effective for treating active Crohn's disease, we conducted a prospective randomised clinical trial in 30 patients with active Crohn's disease unresponsive to steroids and/or complicated by malnutrition. They received a four to six week enteral nutrition course with either an elemental diet or a polymeric diet. Clinical remission occurred in 10 of the 15 patients on elemental diet compared with 11 of the 15 patients assigned to polymeric diet. Both groups showed similar improvements in nutritional status, biological inflammation, alpha 1 antitrypsin clearance, and colonoscopic lesions (diminished in 17 out of 24 patients). Most patients relapsed during the year after discharge. We conclude that enteral nutrition, whatever the diet, is an efficient primary therapy for active Crohn's disease but does not influence the long term outcome. PMID:1773955

  20. An active DNA transposon nDart causing leaf variegation and mutable dwarfism and its related elements in rice.

    PubMed

    Tsugane, Kazuo; Maekawa, Masahiko; Takagi, Kyoko; Takahara, Hiroyuki; Qian, Qian; Eun, Chang-Ho; Iida, Shigeru

    2006-01-01

    While characterized mutable alleles caused by DNA transposons have been abundant in maize since the discovery of Dissociation conferring variegation by Barbara McClintock, only a few mutable alleles have been described in rice even though the rice genome contains various transposons. Here, we show that a spontaneous mutable virescent allele, pyl-v, is caused by the disruption of the nuclear-coded essential chloroplast protease gene, OsClpP5, due to insertion of a 607-bp non-autonomous DNA transposon, non-autonomous DNA-based active rice transposon one (nDart1), belonging to the hAT superfamily. The transposition of nDart1 can be induced by crossing with a line containing an autonomous element, aDart, and stabilized by segregating out of aDart. We also identified a novel mutable dwarf allele thl-m caused by an insertion of nDart1. The japonica cultivar Nipponbare carries no aDart, although it contains epigenetically silenced Dart element(s), which can be activated by 5-azacytidine. Nipponbare bears four subgroups of about 3.6-kb Dart-like sequences, three of which contain potential transposase genes, and around 3.6-kb elements without an apparent transposase gene, as well as three subgroups of about 0.6-kb nDart1-related elements that are all internal deletions of the Dart-like sequences. Both nDart1 and 3.6-kb Dart-like elements were also present in indica varieties 93-11 and Kasalath. nDart1 appears to be the most active mutagen among nDart1-related elements contributing to generating natural variations. A candidate for an autonomous element, aDart, and a possible application of nDart1 for transposon tagging are discussed. PMID:16367953

  1. Influence of panel fastening on the acoustic performance of light-weight building elements: Study by sound transmission and laser scanning vibrometry

    NASA Astrophysics Data System (ADS)

    Roozen, N. B.; Muellner, H.; Labelle, L.; Rychtáriková, M.; Glorieux, C.

    2015-06-01

    Structural details and workmanship can cause considerable differences in sound insulation properties of timber frame partitions. In this study, the influence of panel fastening is investigated experimentally by means of standardized sound reduction index measurements, supported by detailed scanning laser Doppler vibrometry. In particular the effect of the number of screws used to fasten the panels to the studs, and the tightness of the screws, is studied using seven different configurations of lightweight timber frame building elements. In the frequency range from 300 to 4000 Hz, differences in the weighted sound reduction index RW as large as 10 dB were measured, suggesting that the method of fastening can have a large impact on the acoustic performance of building elements. Using the measured vibrational responses of the element, its acoustic radiation efficiency was computed numerically by means of a Rayleigh integral. The increased radiation efficiency partly explains the reduced sound reduction index. Loosening the screws, or reducing the number of screws, lowers the radiation efficiency, and significantly increases the sound reduction index of the partition.

  2. Assessment of disease activity in patients with rheumatoid arthritis using optical spectral transmission measurements, a non-invasive imaging technique

    PubMed Central

    van Onna, M; Ten Cate, D F; Tsoi, K L; Meier, A J L; Jacobs, J W G; Westgeest, A A A; Meijer, P B L; van Beek, M C; Rensen, W H J; Bijlsma, J W J

    2016-01-01

    Objectives In rheumatoid arthritis (RA), treat-to-target strategies require instruments for valid detection of joint inflammation. Therefore, imaging modalities are increasingly used in clinical practice. Optical spectral transmission (OST) measurements are non-invasive and fast and may therefore have benefits over existing imaging modalities. We tested whether OST could measure disease activity validly in patients with RA. Methods In 59 patients with RA and 10 patients with arthralgia, OST, joint counts, Disease Activity Score (DAS) 28 and ultrasonography (US) were performed. Additionally, MRI was performed in patients with DAS28<2.6. We developed and validated within the same cohort an algorithm for detection of joint inflammation by OST with US as reference. Results At the joint level, OST and US performed similarly inproximal interphalangeal-joints (area under the receiver-operating curve (AUC) of 0.79, p<0.0001) andmetacarpophalangeal joints (AUC 0.78, p<0.0001). Performance was less similar in wrists (AUC 0.62, p=0.006). On the patient level, OST correlated moderately with clinical examination (DAS28 r=0.42, p=0.001), and US scores (r=0.64, p<0.0001). Furthermore, in patients with subclinical and low disease activity, there was a correlation between OST and MRI synovitis score (RAMRIS (Rheumatoid Arthritis MRI Scoring) synovitis), r=0.52, p=0.005. Conclusions In this pilot study, OST performed moderately in the detection of joint inflammation in patients with RA. Further studies are needed to determine the diagnostic performance in a new cohort of patients with RA. PMID:26452538

  3. Elemental mapping of Neuromelanin organelles of human Substantia Nigra: correlative ultrastructural and chemical analysis by analytical transmission electron microscopy and nano-secondary ion mass spectrometry.

    PubMed

    Biesemeier, Antje; Eibl, Oliver; Eswara, Santhana; Audinot, Jean-Nicolas; Wirtz, Tom; Pezzoli, Gianni; Zucca, Fabio A; Zecca, Luigi; Schraermeyer, Ulrich

    2016-07-01

    Neuromelanin (NM) is a compound which highly accumulates mainly in catecholamine neurons of the substantia nigra (SN), and is contained in organelles (NM-containing organelles) with lipid bodies and proteins. These neurons selectively degenerate in Parkinson's disease and NM can play either a protective or toxic role. NM-containing organelles of SN were investigated by Analytical Electron Microscopy (AEM) and Nano-Secondary Ion Mass Spectrometry (NanoSIMS) within human tissue sections with respect to ultrastructure and elemental composition. Within the NM-containing organelle, the single NM granules and lipid bodies had sizes of about 200-600 nm. Energy-Dispersive X-ray microanalysis spectra of the NM granules and lipid bodies were acquired with 100 nm beam diameter in AEM, NanoSIMS yielded elemental maps with a lateral resolution of about 150 nm. AEM yielded the quantitative elemental composition of NM granules and bound metals, e.g., iron with a mole fraction of about 0.15 atomic percent. Chemical analyses by AEM and NanoSIMS were consistent at the subcellular level so that nanoSIMS measurements have been quantitated. In NM granules of SN from healthy subjects, a significant amount of S, Fe, and Cu was found. In lipid bodies an amount of P consistent with the presence of phospholipids was measured. The improved detection limits of nanoSIMS offer new possibilities for chemical mapping, high-sensitivity trace element detection, and reduced acquisition times. Variations between individual NM granules can now be investigated effectively and quantitatively by NanoSIMS mapping Cu and Fe. This should yield new insight into the changes in chemical composition of NM pigments during healthy aging and disease. Neuromelanin-containing organelles of dopamine neurons in normal human substantia nigra were investigated by analytical electron mircoscopy and secondary ion mass spectroscopy (NanoSIMS) yielding the ultrastructure and elemental composition. In neuromelanin

  4. Assessment of Transition Element Speciation in Glasses Using a Portable Transmission Ultraviolet-Visible-Near-Infrared (UV-Vis-NIR) Spectrometer.

    PubMed

    Hunault, Myrtille; Lelong, Gérald; Gauthier, Michel; Gélébart, Frédéric; Ismael, Saindou; Galoisy, Laurence; Bauchau, Fanny; Loisel, Claudine; Calas, Georges

    2016-05-01

    A new low-cost experimental setup based on two compact dispersive optical spectrometers has been developed to measure optical absorption transmission spectra over the 350-2500 nm energy range. We demonstrate how near-infrared (NIR) data are essential to identify the coloring species in addition to ultraviolet visible data. After calibration with reference glasses, the use of an original sample stage that maintains the window panel in the vertical position enables the comparison of ancient and modern glasses embedded in a panel from the Sainte-Chapelle of Paris, without any sampling. The spectral resolution enables to observe fine resonances arising in the absorption bands of Cr(3+), and the complementary information obtained in the NIR enables to determine the contribution of Fe(2+), a key indicator of glassmaking conditions. PMID:26988660

  5. Gas transmission through microporous membranes

    NASA Astrophysics Data System (ADS)

    Turel, Tacibaht

    2008-10-01

    An ideal protective clothing material should be a good barrier against harmful gases or vapor while allowing moisture vapor and air passage through the material. In the study and design of barrier materials, one of the critical issues is to balance these requirements, which may sometimes be mutually exclusive. Therefore it is critical to understand the macroscopic and microscopic structure of the attack mechanisms as well as the barrier materials and the transport phenomena in such systems. In this study, air and gas transmission through barrier systems consisting of porous membranes was investigated experimentally and a molecular-level probabilistic model was constructed to evaluate the effect of various parameters on the gas flow. The effect of membrane parameters such as porosity, pore size distribution, thickness as well as gas parameters such as molecule diameters were examined at single layer as well as multiple layers. To understand the gas behavior for harmful chemicals and to ensure safety during experimental studies, mimics of such gases were obtained which were comparable to the actual gases in shape, molecular weight and other chemical properties. Air, ammonia and several mimic gases of harmful chemical agents were studied. Beta-pinene was used as a mimic of sarin and prenol was used as a mimic of nitrogen mustard. Gas transmission experiments were conducted on polyester, nylon and polypropylene membranes each of which had different porosity and pore size distributions. Experiments were done at different pressure values and a comparison was made between permeability testing machines based on volumetric and manometric principles as to their ability to accommodate high permeability membranes. Physical and chemical adsorption of such gases on porous membranes was also investigated after the addition of active elements on the membrane surfaces which can interact with the gas molecules. An experimental setup was developed to measure concentration changes

  6. Elements of M-I Coupling in Repetitive Substorm Activity Driven by Interplanetary CMEs

    NASA Astrophysics Data System (ADS)

    Farrugia, C. J.; Sandholt, P. E.

    2014-12-01

    By means of case studies we explore key elements of the magnetosphere-ionosphere current system associated with repetitive substorm activity during persistent strong forcing by ICMEs. Our approach consists of a combination of the magnetospheric and ionospheric perspectives on the substorm activity. The first aspect is the near-Earth plasma sheet with its repetitive excitations of the substorm current wedge, as monitored by spacecraft GOES-10 when it traversed the 2100-0300 MLT sector, and its coupling to the westward auroral electrojet (WEJ) centered near midnight during the stable interplanetary (IP) conditions. The second aspect is the excitation of Bostrom type II currents maximizing at dusk and dawn and their associated ionospheric Pedersen current closure giving rise to EEJ (WEJ) events at dusk (dawn). As documented in our study, this aspect is related to the braking phase of Earthward-moving dipolarization fronts-bursty bulk flows. We follow the magnetospheric flow/field events from spacecraft Geotail in the midtail (X = - 11 Re) lobe to geostationary altitude at pre-dawn MLTs (GOES 10). The associated M-I coupling is obtained from ground-satellite conjunctions across the double auroral oval configuration along the meridian at dusk. By this technique we distinguish between ionospheric manifestations in three latitude regimes: (i) auroral oval south, (ii) auroral oval north, and (iii) polar cap. Regime (iii) is characterized by events of enhanced antisunward convection near the polar cap boundary (flow channel events) and in the central polar cap (PCN-index events). The repetitive substorm activity is discussed in the context of the level of IP driving as given by the geoeffective IP electric field (E_KL), magnetotail reconnection (inferred from the PCN-index and spacecraft Wind at X = - 77 Re) and the storm SYM-H index. We distinguish between different variants of the repetitive substorm activity, giving rise to electrojet (AL)-plasma convection (PCN) events

  7. Electron-phonon interaction in three-barrier nanosystems as active elements of quantum cascade detectors

    SciTech Connect

    Tkach, N. V. Seti, Ju. A.; Grynyshyn, Yu. B.

    2015-04-15

    The theory of electron tunneling through an open nanostructure as an active element of a quantum cascade detector is developed, which takes into account the interaction of electrons with confined and interface phonons. Using the method of finite-temperature Green’s functions and the electron-phonon Hamiltonian in the representation of second quantization over all system variables, the temperature shifts and electron-level widths are calculated and the contributions of different electron-phonon-interaction mechanisms to renormalization of the spectral parameters are analyzed depending on the geometrical configuration of the nanosystem. Due to weak electron-phonon coupling in a GaAs/Al{sub 0.34}Ga{sub 0.66}As-based resonant tunneling nanostructure, the temperature shift and rf field absorption peak width are not very sensitive to the electron-phonon interaction and result from a decrease in potential barrier heights caused by a difference in the temperature dependences of the well and barrier band gaps.

  8. Active control of blade vortex interaction noise on a helicopter blade element

    NASA Astrophysics Data System (ADS)

    Ariyur, Kartik B.; Krstic, Miroslav

    1998-07-01

    Blade vortex interaction (BVI) noise has been recognized as the primary determinant of the helicopter's far field acoustic signature. Given the limitations of design in eliminating this dynamic phenomenon, there exists a need for control. In this paper, we present the application, first of feedback control strategies, and then of adaptive cancellation of Leishman and Hariharan's linear aerodynamic model of a trailing edge flap. Lift fluctuations caused by vortices are taken as output disturbance. The contribution of the vortices to lift is obtained from Leishman's indicial model for gusts. The use of an active structure for actuation is assumed, and the actuator is approximated as a lag element. To design an adaptive cancellation scheme that is applicable not only to BVI but also to general problems with periodic disturbances, we start with the sensitivity method but arrive at the same scheme derived by Sacks, Bodson, and Khosla who introduced a phase advance into a pseudo-gradient scheme. We discuss stability of the scheme via averaging.

  9. Transcriptional activity of the transposable element Tn10 in the Salmonella typhimurium ilvGEDA operon.

    PubMed

    Blazey, D L; Burns, R O

    1982-08-01

    Polarity of Tn10 insertion mutations in the Salmonella typhimurium ilvGEDA operon depends on both the location and the orientation of the Tn10 element. One orientation of Tn10 insertions in ilvG and ilvE permits low-level expression of the downstream ilvEDA and ilvDA genes, respectively. Our analysis of Salmonella ilv recombinant plasmids shows that this residual ilv expression must result from Tn10-directed transcription and does not reflect the presence of internal promoters in the ilvGEDA operon, as was previously suggested. The opposite orientation of Tn10 insertion in ilvE prevents ilvDA expression, indicating that only one end of Tn10 is normally active in transcribing adjacent genes. Both orientations of Tn10 insertion in ilvD exert absolute polarity on ilvA expression. Expression of ilvA is known to be dependent on effective translation of ilvD, perhaps reflecting the lack of a ribosome binding site proximal to the ilvA sequence. Therefore, recognition of the ability of Tn10 to promote transcription of contiguous genes in the ilvGEDA operon apparently requires the presence of associated ribosome binding sites. PMID:6289328

  10. Activation of Elemental Sulfur at a Two-Coordinate Platinum(0) Center.

    PubMed

    Roy, Sudipta; Schürmann, Christian J; Mondal, Totan; Koley, Debasis; Herbst-Irmer, Regine; Stalke, Dietmar; Roesky, Herbert W

    2016-08-26

    Platinum dichalcogenides have been known to exhibit two-dimensional layered structures. Herein, we describe the syntheses, isolation, and characterization of air-stable crystalline cyclic alkyl(amino) carbene (cAAC)-supported monomeric platinum disulfide three-membered ring complex [(cAAC)2 Pt(S2 )] (2). The highly reactive platinum(0) [(cAAC)2 Pt] complex (1) with two-coordinate platinum activates elemental sulfur to give 2. The brown crystals of bis-carbene platinum(II)monosulfate [(cAAC)2 Pt(SO4 )x (S2 )1-x ] (4) have been isolated when the reaction was performed in air. The dioxygen analogue of 2 was formed upon exposing the THF solution of 1 to aerial oxygen (O2 ). The binding of oxygen at the Pt(0) center was found to be reversible. Additionally, DFT study has been performed to elucidate the electronic structure and bonding scenario of 2, 3, and 4. Quantum chemical calculations showed donor-acceptor-type interaction for the Pt-S bonds in 2 and Pt-O bonds in 3 and 4. PMID:27414489

  11. Transposable Elements Contribute to Activation of Maize Genes in Response to Abiotic Stress

    PubMed Central

    Makarevitch, Irina; Waters, Amanda J.; West, Patrick T.; Stitzer, Michelle; Hirsch, Candice N.; Ross-Ibarra, Jeffrey; Springer, Nathan M.

    2015-01-01

    Transposable elements (TEs) account for a large portion of the genome in many eukaryotic species. Despite their reputation as “junk” DNA or genomic parasites deleterious for the host, TEs have complex interactions with host genes and the potential to contribute to regulatory variation in gene expression. It has been hypothesized that TEs and genes they insert near may be transcriptionally activated in response to stress conditions. The maize genome, with many different types of TEs interspersed with genes, provides an ideal system to study the genome-wide influence of TEs on gene regulation. To analyze the magnitude of the TE effect on gene expression response to environmental changes, we profiled gene and TE transcript levels in maize seedlings exposed to a number of abiotic stresses. Many genes exhibit up- or down-regulation in response to these stress conditions. The analysis of TE families inserted within upstream regions of up-regulated genes revealed that between four and nine different TE families are associated with up-regulated gene expression in each of these stress conditions, affecting up to 20% of the genes up-regulated in response to abiotic stress, and as many as 33% of genes that are only expressed in response to stress. Expression of many of these same TE families also responds to the same stress conditions. The analysis of the stress-induced transcripts and proximity of the transposon to the gene suggests that these TEs may provide local enhancer activities that stimulate stress-responsive gene expression. Our data on allelic variation for insertions of several of these TEs show strong correlation between the presence of TE insertions and stress-responsive up-regulation of gene expression. Our findings suggest that TEs provide an important source of allelic regulatory variation in gene response to abiotic stress in maize. PMID:25569788

  12. Characterization of active miniature inverted-repeat transposable elements in the peanut genome.

    PubMed

    Shirasawa, Kenta; Hirakawa, Hideki; Tabata, Satoshi; Hasegawa, Makoto; Kiyoshima, Hiroyuki; Suzuki, Sigeru; Sasamoto, Sigemi; Watanabe, Akiko; Fujishiro, Tsunakazu; Isobe, Sachiko

    2012-05-01

    Miniature inverted-repeat transposable elements (MITEs), some of which are known as active nonautonomous DNA transposons, are found in the genomes of plants and animals. In peanut (Arachis hypogaea), Ah-MITE1 has been identified in a gene for fatty-acid desaturase, and possessed excision activity. However, the AhMITE1 distribution and frequency of excision have not been determined for the peanut genome. In order to characterize AhMITE1s, their genomic diversity and transposition ability was investigated. Southern blot analysis indicated high AhMITE1 copy number in the genomes of A. hypogaea, A. magna and A. monticola, but not in A. duranensis. A total of 504 AhMITE1s were identified from the MITE-enriched genomic libraries of A. hypogaea. The representative AhMITE1s exhibited a mean length of 205.5 bp and a GC content of 30.1%, with AT-rich, 9 bp target site duplications and 25 bp terminal inverted repeats. PCR analyses were performed using primer pairs designed against both flanking sequences of each AhMITE1. These analyses detected polymorphisms at 169 out of 411 insertional loci in the four peanut lines. In subsequent analyses of 60 gamma-irradiated mutant lines, four Ah-MITE1 excisions showed footprint mutations at the 109 loci tested. This study characterizes AhMITE1s in peanut and discusses their use as DNA markers and mutagens for the genetics, genomics and breeding of peanut and its relatives. PMID:22294450

  13. Transcriptional Activity, Chromosomal Distribution and Expression Effects of Transposable Elements in Coffea Genomes

    PubMed Central

    da Silva, Carlos R. M.; Andrade, Alan C.; Marraccini, Pierre; Teixeira, João B.; Carazzolle, Marcelo F.; Pereira, Gonçalo A. G.; Pereira, Luiz Filipe P.; Vanzela, André L. L.; Wang, Lu; Jordan, I. King; Carareto, Claudia M. A.

    2013-01-01

    Plant genomes are massively invaded by transposable elements (TEs), many of which are located near host genes and can thus impact gene expression. In flowering plants, TE expression can be activated (de-repressed) under certain stressful conditions, both biotic and abiotic, as well as by genome stress caused by hybridization. In this study, we examined the effects of these stress agents on TE expression in two diploid species of coffee, Coffea canephora and C. eugenioides, and their allotetraploid hybrid C. arabica. We also explored the relationship of TE repression mechanisms to host gene regulation via the effects of exonized TE sequences. Similar to what has been seen for other plants, overall TE expression levels are low in Coffea plant cultivars, consistent with the existence of effective TE repression mechanisms. TE expression patterns are highly dynamic across the species and conditions assayed here are unrelated to their classification at the level of TE class or family. In contrast to previous results, cell culture conditions per se do not lead to the de-repression of TE expression in C. arabica. Results obtained here indicate that differing plant drought stress levels relate strongly to TE repression mechanisms. TEs tend to be expressed at significantly higher levels in non-irrigated samples for the drought tolerant cultivars but in drought sensitive cultivars the opposite pattern was shown with irrigated samples showing significantly higher TE expression. Thus, TE genome repression mechanisms may be finely tuned to the ideal growth and/or regulatory conditions of the specific plant cultivars in which they are active. Analysis of TE expression levels in cell culture conditions underscored the importance of nonsense-mediated mRNA decay (NMD) pathways in the repression of Coffea TEs. These same NMD mechanisms can also regulate plant host gene expression via the repression of genes that bear exonized TE sequences. PMID:24244387

  14. The cAMP response element binding protein, CREB, is a potent inhibitor of diverse transcriptional activators.

    PubMed Central

    Lemaigre, F P; Ace, C I; Green, M R

    1993-01-01

    Cyclic AMP response element binding protein (CREB) activates transcription of cAMP response element (CRE)-containing promoters following an elevation of intracellular cAMP. Here we show that CREB and the highly related protein ATF-1 are also potent transcription inhibitors. Strikingly, CREB inhibits transcription of multiple activators, whose DNA-binding domains and activation regions are unrelated to one another. Inhibition requires that the CREB dimerization and DNA-binding domains are intact. However, inhibition is not dependent upon the presence of a CRE in the promoter, and does not involve heterodimer formation between CREB and the activator. The ability of an activator protein to inhibit transcription in such a promiscuous fashion has not been previously reported. Images PMID:8332500

  15. Transmission Line Security Monitor

    SciTech Connect

    2011-01-01

    The Transmission Line Security Monitor is a multi-sensor monitor that mounts directly on high-voltage transmission lines to detect, characterize and communicate terrorist activity, human tampering and threatening conditions around support towers. For more information about INL's critical infrastructure protection research, visit http://www.facebook.com/idahonationallaboratory.

  16. Transmission Line Security Monitor

    ScienceCinema

    None

    2013-05-28

    The Transmission Line Security Monitor is a multi-sensor monitor that mounts directly on high-voltage transmission lines to detect, characterize and communicate terrorist activity, human tampering and threatening conditions around support towers. For more information about INL's critical infrastructure protection research, visit http://www.facebook.com/idahonationallaboratory.

  17. Non destructive multi elemental analysis using prompt gamma neutron activation analysis techniques: Preliminary results for concrete sample

    SciTech Connect

    Dahing, Lahasen Normanshah; Yahya, Redzuan; Yahya, Roslan; Hassan, Hearie

    2014-09-03

    In this study, principle of prompt gamma neutron activation analysis has been used as a technique to determine the elements in the sample. The system consists of collimated isotopic neutron source, Cf-252 with HPGe detector and Multichannel Analysis (MCA). Concrete with size of 10×10×10 cm{sup 3} and 15×15×15 cm{sup 3} were analysed as sample. When neutrons enter and interact with elements in the concrete, the neutron capture reaction will occur and produce characteristic prompt gamma ray of the elements. The preliminary result of this study demonstrate the major element in the concrete was determined such as Si, Mg, Ca, Al, Fe and H as well as others element, such as Cl by analysis the gamma ray lines respectively. The results obtained were compared with NAA and XRF techniques as a part of reference and validation. The potential and the capability of neutron induced prompt gamma as tool for multi elemental analysis qualitatively to identify the elements present in the concrete sample discussed.

  18. A Priori Method of Using Photon Activation Analysis to Determine Unknown Trace Element Concentrations in NIST Standards

    SciTech Connect

    Green, Jaromy; Sun Zaijing; Wells, Doug; Benson, Buck; Maschner, Herb

    2009-03-10

    Photon activation analysis detected elements in two NIST standards that did not have reported concentration values. A method is currently being developed to infer these concentrations by using scaling parameters and the appropriate known quantities within the NIST standard itself. Scaling parameters include: threshold, peak and endpoint energies; photo-nuclear cross sections for specific isotopes; Bremstrahlung spectrum; target thickness; and photon flux. Photo-nuclear cross sections and energies from the unknown elements must also be known. With these quantities, the same integral was performed for both the known and unknown elements resulting in an inference of the concentration of the un-reported element based on the reported value. Since Rb and Mn were elements that were reported in the standards, and because they had well-identified peaks, they were used as the standards of inference to determine concentrations of the unreported elements of As, I, Nb, Y, and Zr. This method was tested by choosing other known elements within the standards and inferring a value based on the stated procedure. The reported value of Mn in the first NIST standard was 403{+-}15 ppm and the reported value of Ca in the second NIST standard was 87000 ppm (no reported uncertainty). The inferred concentrations were 370{+-}23 ppm and 80200{+-}8700 ppm respectively.

  19. Studies on the introduction and mobility of the maize Activator element in Arabidopsis thaliana and Daucus carota.

    PubMed Central

    Van Sluys, M A; Tempé, J; Fedoroff, N

    1987-01-01

    We have co-transformed carrot (Daucus carota) and Arabidopsis thaliana with an Agrobacterium tumefaciens non-tumorigenic T-DNA carrying the maize transposable element Activator (Ac) and an Agrobacterium rhizogenes Ri T-DNA. We present evidence that the Ac element transposes in transformed root or root-derived callus cultures of both species. We show that fertile plants can be regenerated from transformed, root-derived callus cultures of Arabidopsis, demonstrating the utility of the Ri plasmid for introducing the maize Ac element into plants. We also present evidence that Ac elements that excise from the transforming T-DNA early after transformation continue to be mobile in carrot root cultures. Images Fig. 2. Fig. 3. Fig. 4. Fig. 5. Fig. 6. Fig. 7. PMID:2832144

  20. Multiple single-stranded cis elements are associated with activated chromatin of the human c-myc gene in vivo.

    PubMed Central

    Michelotti, G A; Michelotti, E F; Pullner, A; Duncan, R C; Eick, D; Levens, D

    1996-01-01

    Transcription activation and repression of eukaryotic genes are associated with conformational and topological changes of the DNA and chromatin, altering the spectrum of proteins associated with an active gene. Segments of the human c-myc gene possessing non-B structure in vivo located with enzymatic and chemical probes. Sites hypertensive to cleavage with single-strand-specific S1 nuclease or the single-strand-selective agent potassium permanganate included the major promoters P1 and P2 as well as the far upstream sequence element (FUSE) and CT elements, which bind, respectively, the single-strand-specific factors FUSE-binding protein and heterogeneous nuclear ribonucleoprotein K in vitro. Active and inactive c-myc genes yielded different patterns of S1 nuclease and permanganate sensitivity, indicating alternative chromatin configurations of active and silent genes. The melting of specific cis elements of active c-myc genes in vivo suggested that transcriptionally associated torsional strain might assist strand separation and facilitate factor binding. Therefore, the interaction of FUSE-binding protein and heterogeneous nuclear ribonucleoprotein K with supercoiled DNA was studied. Remarkably, both proteins recognize their respective elements torsionally strained but not as liner duplexes. Single-strand- or supercoil-dependent gene regulatory proteins may directly link alterations in DNA conformation and topology with changes in gene expression. PMID:8649373

  1. Onchocerciasis transmission levels and Simulium damnosum complex biting activity at riverside and rice field sites in Sierra Leone.

    PubMed

    Davies, J B; Beech-Garwood, P A; Thomson, M C; McMahon, J E

    1988-10-01

    Biting densities of the Simulium damnosum Theobald complex of blackflies and their levels of parasitism by Onchocerca volvulus (Leuckart) were compared at two ecologically contrasted sites in the Southern Province of Sierre Leone, West Africa: by the Tabe riverside close to Gbaiima village where onchocerciasis is hyperendemic (63.1% positive skin-snips) and in open rice fields 2 km from the mesoendemic (54.9%) village of Senehun. Using a combination of morphometric and enzyme electrophoresis techniques, the primary vector was found to belong to the S.sanctipauli subcomplex and was most probably S.soubrense 'B' (sensu Post, 1986). In the wet season biting activity took place throughout the day at the village, but had morning and evening peaks in the rice fields. Transmission of O.volvulus was detected at the village in all months except February-April, while in the rice fields it was detected only during September-November and May at one tenth the level of the village. There was a significant difference between the two sites in the proportion of parous flies carrying third stage larvae in the head, but not of other larval stages. PMID:2980195

  2. Measurement of active content in escitalopram tablets by a near-infrared transmission spectroscopy model that encompasses batch variability.

    PubMed

    Warnecke, Solveig; Rinnan, Åsmund; Allesø, Morten; Engelsen, Søren Balling

    2013-04-01

    Near-infrared transmission (NIT) spectroscopy, with high-performance liquid chromatography as reference method, was used to study the variation of the active pharmaceutical ingredient (API), escitalopram, in five tablet batches (4%-12%, w/w) manufactured by direct compression. This study investigates the influence of sample orientation, powder segregation, and compression force on the NIT spectra. For this purpose, tablet samples were taken at six different production time points, at three different compression forces, and presented to the spectrometer in four different orientations and in three spectroscopic replicates. A total set of 2160 NIT spectra was recorded. The variances between the spectra at each level of API content were thoroughly investigated by partial least squares regression using theory of sampling. The results show that a minimum of 18 tablets from each level of API content is required to establish a robust NIT calibration. The identified number of spectra is required for covering small differences in the spatial heterogeneity of the API as well as minor variations in optical properties, due to variations in the tablet compression force. NIT spectroscopy is demonstrated to be a powerful technique not only for measuring the API content in escitalopram tablets but also for routine content uniformity analysis. PMID:23381884

  3. Determination of fission neutron transmission through waste matrix material using neutron signal correlation from active assay of {sup 239}Pu

    SciTech Connect

    Hollas, C.L.; Arnone, G.; Brunson, G.; Coop, K.

    1996-09-01

    The accuracy of TRU (transuranic) waste assay using the differential die-away technique depends upon significant corrections to compensate for the effects of the matrix material in which the TRU waste is located. The authors have used a new instrument, the Combined Thermal/Epithermal Neutron (CTEN) instrument for the assay of TRU waste, to develop methods to improve the accuracy of these corrections. Neutrons from a pulsed 14-MeV neutron generator are moderated in the walls of the CTEN cavity and induce fission in the TRU material. The prompt neutrons from these fission events are detected in cadmium-wrapped {sup 3}He neutron detectors. They report new methods of data acquisition and analysis to extract correlation in the neutron signals resulting form fission during active interrogation. They use the correlation information in conjunction with the total number of neutrons to determine the fraction of fission neutrons transmitted through the matrix material into the {sup 3}He detectors. This determination allows them to cleanly separate the matrix effects into two processes: matrix modification upon the neutron interrogating flux and matrix modification upon the fraction of fission neutrons transmitted to the neutron detectors. This transmission information is also directly applied in a neutron multiplicity analysis in the passive assay of {sup 240}Pu.

  4. Alteration of rare earth element distribution as a result of microbial activity and empirical methane injection

    NASA Astrophysics Data System (ADS)

    Castillo, D. J.; Davies, N. W.; Thurber, A. R.; Haley, B. A.; Colwell, F. S.

    2014-12-01

    As a result of warming, methane is being released into the marine environment in areas that have not historically experienced methane input. While methane is a potent greenhouse gas, microbial oxidation of methane within the sediment greatly limits the role of marine methane sources on atmospheric forcing. However, in these areas of new methane release, consumption of methane prior to its release into the atmosphere is a result of the response of the microbial community to this new input of methane. Further, rare earth elements (REEs) are not currently thought to be involved with microbial activity, but this assumption has not been rigorously tested. Here we test that: (1) microbial communities will rapidly respond to the onset of methane emission, and (2) the microbial response to this methane input will impact the distribution of REEs within the sediment. Undisturbed cores sampled from a tidal flat at Yaquina Bay, OR, were brought back to a lab and injected with anoxic seawater (as a control) or anoxic sea water saturated with methane gas for a total of 2 weeks. Aerobic methanotrophs proliferated over this short time period, becoming an abundant member of the microbial community as identified using fatty acid biomarkers. Excitingly, the experimental injection of methane also shifted the distribution of REEs within the sediment, a trend that appeared to follow the microbial response and that was different from the control cores. Further, the lightest REEs appeared to be used more than the heavier ones, supporting that the REEs are being actively used by the microbes. While we focused on identifying the response of those microbes responsible in methane-cycling, we also identified how the entire microbial community shifts as a result of methane input, and correlating with shifts in REE distribution. Here we have empirically demonstrated the rapid response of methanotrophs to the onset of methane emission and that REE distribution within the sediment is likely

  5. Quantitative Analysis of Cis-Regulatory Element Activity Using Synthetic Promoters in Transgenic Plants.

    PubMed

    Benn, Geoffrey; Dehesh, Katayoon

    2016-01-01

    Synthetic promoters, introduced stably or transiently into plants, are an invaluable tool for the identification of functional regulatory elements and the corresponding transcription factor(s) that regulate the amplitude, spatial distribution, and temporal patterns of gene expression. Here, we present a protocol describing the steps required to identify and characterize putative cis-regulatory elements. These steps include application of computational tools to identify putative elements, construction of a synthetic promoter upstream of luciferase, identification of transcription factors that regulate the element, testing the functionality of the element introduced transiently and/or stably into the species of interest followed by high-throughput luciferase screening assays, and subsequent data processing and statistical analysis. PMID:27557758

  6. Active Sphagnum girgensohnii Russow Moss Biomonitoring of an Industrial Site in Romania: Temporal Variation in the Elemental Content.

    PubMed

    Culicov, Otilia A; Zinicovscaia, Inga; Duliu, O G

    2016-05-01

    The moss-bag transplant technique was used to investigate the kinetics of the accumulation of 38 elements in Sphagnum girgensohni moss samples in the highly polluted municipality of Baia Mare, Romania. The moss samples collected from the unpolluted Vitosha Mountain Natural Reserve, Bulgaria, were analyzed after 1, 2, 3, and 4 months of exposure, respectively. The ANOVA method was used to assay the statistical significance of the observed changes in elemental content, as determined by neutron activation analysis. The content of Zn, Se, As, Ag, Cd, and Sb increased steadily, while that of physiologically active K and Cl, as well as Rb and Cs, decreased exponentially. The study showed that an adequate application of the moss transplant technique in an urban environment should consider the exposure time as a critical parameter, since particular elements are depleted in the moss at sites with high atmospheric loading of metals. PMID:27003805

  7. Radionuclide Compositions and Total Activity of Spent MTR-HEU Fuel Elements of the IAN-R1 Research Reactor

    NASA Astrophysics Data System (ADS)

    Sarta, Josè A.; Castiblanco, Luis A.

    2005-05-01

    With cooperation of the International Atomic Energy Agency (IAEA) and the Department of Energy (DOE) of the United States, several calculations and tasks related to the waste disposal of spent MTR fuel enriched nominally to 93% were carried out for the conversion of the IAN-R1 Research Reactor from MTR-HEU fuel to TRIGA-LEU fuel. In order to remove the spent MTR-HEU fuel of the core and store it safely a program was established at the Instituto de Ciencias Nucleares y Energìas Alternativas (INEA). This program included training, acquisition of hardware and software, design and construction of a decay pool, transfer of the spent HEU fuel elements into the decay pool and his final transport to Savannah River in United States. In this paper are presented data of activities calculated for each relevant radionuclide present in spent MTR-HEU fuel elements of the IAN-R1 Research Reactor and the total activity. The total activity calculated takes in consideration contributions of fission, activation and actinides products. The data obtained were the base for shielding calculations for the decay pool concerning the storage of spent MTR-HEU fuel elements and the respective dosimetric evaluations in the transferring operations of fuel elements into the decay pool.

  8. Radionuclide Compositions and Total Activity of Spent MTR-HEU Fuel Elements of the IAN-R1 Research Reactor

    SciTech Connect

    Sarta, Jose A.; Castiblanco, Luis A

    2005-05-24

    With cooperation of the International Atomic Energy Agency (IAEA) and the Department of Energy (DOE) of the United States, several calculations and tasks related to the waste disposal of spent MTR fuel enriched nominally to 93% were carried out for the conversion of the IAN-R1 Research Reactor from MTR-HEU fuel to TRIGA-LEU fuel. In order to remove the spent MTR-HEU fuel of the core and store it safely a program was established at the Instituto de Ciencias Nucleares y Energias Alternativas (INEA). This program included training, acquisition of hardware and software, design and construction of a decay pool, transfer of the spent HEU fuel elements into the decay pool and his final transport to Savannah River in United States. In this paper are presented data of activities calculated for each relevant radionuclide present in spent MTR-HEU fuel elements of the IAN-R1 Research Reactor and the total activity. The total activity calculated takes in consideration contributions of fission, activation and actinides products. The data obtained were the base for shielding calculations for the decay pool concerning the storage of spent MTR-HEU fuel elements and the respective dosimetric evaluations in the transferring operations of fuel elements into the decay pool.

  9. NEUTRON ACTIVATION ANALYSIS FOR SIMULTANEOUS DETERMINATION OF TRACE ELEMENTS IN AMBIENT AIR COLLECTED ON GLASS-FIBER FILTERS

    EPA Science Inventory

    Arsenic with 25 other elements are simultaneously determined in ambient air samples collected on glass-fiber filter composites at 250 United States sites. The instrumental neutron activation analysis (NAA) technique combined with the power of a dedicated mini-computer resulted in...

  10. High-field actively detuneable transverse electromagnetic (TEM) coil with low-bias voltage for high-power RF transmission.

    PubMed

    Avdievich, Nikolai I; Bradshaw, Ken; Kuznetsov, Andrey M; Hetherington, Hoby P

    2007-06-01

    The design and construction of a 4T (170 MHz) transverse electromagnetic (TEM) actively detuneable quadrature head coil is described. Conventional schemes for active detuning require high negative bias voltages (>300 V) to prevent leakage of RF pulses with amplitudes of 1-2 kW. To extend the power handling capacity and avoid the use of high DC bias voltages, we developed an alternate method of detuning the volume coil. In this method the PIN diodes in the detuning circuits are shorted when the RF volume coil is tuned, and negatively biased with -12 V when the coil is detuned. To preserve the high Q(U)/Q(L) ratio of the TEM coil, we modified the method of Nabetani and Watkins (Proceedings of the 13th Annual Meeting of ISMRM, Kyoto, Japan, 2004, abstract 1574) by utilizing a high-impedance (approximately 200 Omega), lumped-element, quarter-wavelength transformer. A Q(U) of 500 was achieved for the detuneable TEM, such that incorporation of the detuning network had minimal effect (<1 dB) on the performance of the coil in vivo. PMID:17534919

  11. Atranorin and lecanoric acid antagonize TCDD-induced xenobiotic response element-driven activity, but not xenobiotic response element-independent activity.

    PubMed

    Nakashima, Ken-Ichi; Tanabe, Hiroki; Fujii-Kuriyama, Yoshiaki; Hayashi, Hidetoshi; Inoue, Makoto

    2016-07-01

    Lichens are symbiotic organisms that consist of fungi and photosynthetic symbionts (algae and/or cyanobacteria). Previous studies of their constituents suggested lichens produce many kinds of aromatic secondary metabolites, such as depsides, quinones, and dibenzofurans. In this study, we evaluated the aryl hydrocarbon receptor (AhR) antagonistic activity of 17 lichen substances and demonstrated that atranorin (1) and lecanoric acid (2), isolated from Parmotrema tinctorum Hale, showed an inhibitory effect on luciferase activity increased by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), using an XRE-driven pX4TK-Luc reporter gene assay. In addition, CYP1A1 mRNA and protein levels increased by TCDD were also suppressed by 1 and 2. Conversely, neither 1 nor 2 antagonized the suppressive effect of TCDD on interleukin (IL)-1β-induced acute-phase response (APR) gene expression. Thus, we concluded that 1 and 2 were selective AhR modulators that antagonize XRE-dependent activity, but not XRE-independent activity. However, 1 has different characteristics to 2 in that 1 alone showed a suppressive effect on IL-1β-induced APR gene expression in a similar fashion to TCDD. PMID:26979434

  12. Connecting Mechanics and Bone Cell Activities in the Bone Remodeling Process: An Integrated Finite Element Modeling

    PubMed Central

    Hambli, Ridha

    2014-01-01

    Bone adaptation occurs as a response to external loadings and involves bone resorption by osteoclasts followed by the formation of new bone by osteoblasts. It is directly triggered by the transduction phase by osteocytes embedded within the bone matrix. The bone remodeling process is governed by the interactions between osteoblasts and osteoclasts through the expression of several autocrine and paracrine factors that control bone cell populations and their relative rate of differentiation and proliferation. A review of the literature shows that despite the progress in bone remodeling simulation using the finite element (FE) method, there is still a lack of predictive models that explicitly consider the interaction between osteoblasts and osteoclasts combined with the mechanical response of bone. The current study attempts to develop an FE model to describe the bone remodeling process, taking into consideration the activities of osteoclasts and osteoblasts. The mechanical behavior of bone is described by taking into account the bone material fatigue damage accumulation and mineralization. A coupled strain–damage stimulus function is proposed, which controls the level of autocrine and paracrine factors. The cellular behavior is based on Komarova et al.’s (2003) dynamic law, which describes the autocrine and paracrine interactions between osteoblasts and osteoclasts and computes cell population dynamics and changes in bone mass at a discrete site of bone remodeling. Therefore, when an external mechanical stress is applied, bone formation and resorption is governed by cells dynamic rather than adaptive elasticity approaches. The proposed FE model has been implemented in the FE code Abaqus (UMAT routine). An example of human proximal femur is investigated using the model developed. The model was able to predict final human proximal femur adaptation similar to the patterns observed in a human proximal femur. The results obtained reveal complex spatio-temporal bone

  13. EEG source analysis of epileptiform activity using a 1mm anisotropic hexahedra finite element head model

    PubMed Central

    Rullmann, M.; Anwander, A.; Dannhauer, M.; Warfield, S.K.; Duffy, F.H.; Wolters, C.H.

    2009-01-01

    The major goal of the evaluation in presurgical epilepsy diagnosis for medically intractable patients is the precise reconstruction of the epileptogenic foci, preferably with non-invasive methods. This paper evaluates whether surface electroencephalography (EEG) source analysis based on a 1mm anisotropic finite element (FE) head model can provide additional guidance for presurgical epilepsy diagnosis and whether it is practically feasible in daily routine. A 1mm hexahedra FE volume conductor model of the patient’s head with special focus on accurately modeling the compartments skull, cerebrospinal fluid (CSF) and the anisotropic conducting brain tissues was constructed using non-linearly co-registered T1-, T2- and diffusion-tensor- magnetic resonance imaging data. The electrodes of intra-cranial EEG (iEEG) measurements were extracted from a co-registered computed tomography image. Goal function scan (GFS), minimum norm least squares (MNLS), standardized low resolution electromagnetic tomography (sLORETA) and spatio-temporal current dipole modeling inverse methods were then applied to the peak of the averaged ictal discharges EEG data. MNLS and sLORETA pointed to a single center of activity. Moving and rotating single dipole fits resulted in an explained variance of more than 97%. The non-invasive EEG source analysis methods localized at the border of the lesion and at the border of the iEEG electrodes which mainly received ictal discharges. Source orientation was towards the epileptogenic tissue. For the reconstructed superficial source, brain conductivity anisotropy and the lesion conductivity had only a minor influence, whereas a correct modeling of the highly conducting CSF compartment and the anisotropic skull was found to be important. The proposed FE forward modeling approach strongly simplifies meshing and reduces run-time (37 Milliseconds for one forward computation in the model with 3.1 Million unknowns), corroborating the practical feasibility of the

  14. Recent advances in the application of computer-controlled optical finishing to produce very high-quality transmissive optical elements and windows

    NASA Astrophysics Data System (ADS)

    Askinazi, Joel; Estrin, Aleksandr; Green, Alan; Turner, Aaron N.

    2003-09-01

    Large aperture (20-inch diameter) sapphire optical windows have been identified as a key element of new and/or upgraded airborne electro-optical systems. These windows typically require a transmitted wave front error of much less than 0.1 waves rms @ 0.63 microns over 7 inch diameter sub-apertures. Large aperture (14-inch diameter by 4-inch thick) sapphire substrates have also been identified as a key optical element of the Laser Interferometer Gravitational Wave Observatory (LIGO). This project is under joint development by the California Institute of Technology (Caltech) and the Massachusetts Institute of Technology under cooperative agreement with the National Science foundation (NSF). These substrates are required to have a transmitted wave front error of 20 nm (0.032 waves) rms @ 0.63 microns over 6-inch sub-apertures with a desired error of 10 nm (0.016 waves) rms. Owing to the spatial variations in the optical index of refraction potentially anticipated within 20-inch diameter sapphire, thin (0.25 - 0.5-inch) window substrates, as well as within the 14-inch diameter by 4-inch thick substrates for the LIGO application, our experience tells us that the required transmitted wave front errors can not be achieved with standard optical finishing techniques as they can not readily compensate for errors introduced by inherent material characteristics. Computer controlled optical finishing has been identified as a key technology likely required to enable achievement of the required transmitted wave front errors. Goodrich has developed this technology and has previously applied it to finish high quality sapphire optical windows with a range of aperture sizes from 4-inch to 13-inch to achieve transmitted wavefront errors comparable to these new requirements. This paper addresses successful recent developments and accomplishments in the application of this optical finishing technology to sequentially larger aperture and thicker sapphire windows to achieve the

  15. Spatial and temporal characterization of mosquito distribution and arbovirus transmission activity in St. Johns County, Florida. St. Augustine, FL.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Global information technology (GIT) (including Global Positioning System [GPS], Geographic Information Systems [GIS], and image analysis) can be used to develop adult mosquito sampling methods and to characterize adult mosquito distributions and disease transmission patterns. At this meeting of v...

  16. Activation of antioxidant response element in mouse primary cortical cultures with sesquiterpene lactones isolated from Tanacetum parthenium

    PubMed Central

    Fischedick, Justin T; Standiford, Miranda; Johnson, Delinda A.; De Vos, Ric C.H.; Todorović, Slađana; Banjanac, Tijana; Verpoorte, Rob; Johnson, Jeffrey A.

    2012-01-01

    Tanacetum parthenium (Asteraceae) produces biologically active sesquiterpene lactones (SL). Nuclear factor E2-related factor 2 (Nrf2) is a transcription factor known to activate a series of genes termed the antioxidant response element (ARE). Activation of the Nrf2/ARE may be useful for the treatment of neurodegenerative disease. In this study we isolated 11 sesquiterpene lactones from T. parthenium with centrifugal partition chromatography and semi-preparative HPLC. Compounds were screened in-vitro for their ability to activate the ARE on primary mouse cortical cultures as well as for their toxicity towards the cultures. All sesquiterpene lactones containing the α-methylene-γ-lactone moiety were able to activate the ARE although a number of compounds displayed significant cellular toxicity towards the cultures. The structure activity relationship of the sesquiterpene lactones indicate that the guaianolides isolated were more active and less toxic then the germacranolides. PMID:22923197

  17. Irradiation resistance of intravolume shading elements embedded in photomasks used for CD uniformity control by local intra-field transmission attenuation

    NASA Astrophysics Data System (ADS)

    Zait, Eitan; Ben-Zvi, Guy; Dmitriev, Vladimir; Oshemkov, Sergey; Pforr, Rainer; Hennig, Mario

    2006-05-01

    Intra-field CD variation is, besides OPC errors, a main contributor to the total CD variation budget in IC manufacturing. It is caused mainly by mask CD errors. In advanced memory device manufacturing the minimum features are close to the resolution limit resulting in large mask error enhancement factors hence large intra-field CD variations. Consequently tight CD Control (CDC) of the mask features is required, which results in increasing significantly the cost of mask and hence the litho process costs. Alternatively there is a search for such techniques (1) which will allow improving the intrafield CD control for a given moderate mask and scanner imaging performance. Currently a new technique (2) has been proposed which is based on correcting the printed CD by applying shading elements generated in the substrate bulk of the mask by ultrashort pulsed laser exposure. The blank transmittance across a feature is controlled by changing the density of light scattering pixels. The technique has been demonstrated to be very successful in correcting intra-field CD variations caused by the mask and the projection system (2). A key application criterion of this technique in device manufacturing is the stability of the absorbing pixels against DUV light irradiation being applied during mask projection in scanners. This paper describes the procedures and results of such an investigation. To do it with acceptable effort a special experimental setup has been chosen allowing an evaluation within reasonable time. A 193nm excimer laser with pulse duration of 25 ns has been used for blank irradiation. Accumulated dose equivalent to 100,000 300 mm wafer exposures has been applied to Half Tone PSM mask areas with and without CDC shadowing elements. This allows the discrimination of effects appearing in treated and untreated glass regions. Several intensities have been investigated to define an acceptable threshold intensity to avoid glass compaction or generation of color centers in

  18. Photon Activation Analysis Of Light Elements Using 'Non-Gamma' Radiation Spectroscopy - The Instrumental Determination Of Phosphorus

    SciTech Connect

    Segebade, Christian; Goerner, Wolf

    2011-06-01

    Unlike metal determinations the analysis of light elements (e.g., carbon, oxygen, phosphorus) is frequently problematic, in particular if analysed instrumentally. In photon activation analysis (PAA) the respective activation products do not emit gamma radiation in the most cases. Usually, annihilation quanta counting and subsequent decay curve analysis have been used for determinations of C, N, O, and F. However, radiochemical separation of the respective radioisotopes mostly is indispensable. For several reasons, some of the light elements cannot be analysed following this procedure, e.g. phosphorus. In this contribution the instrumental PAA of phosphorus in organic matrix by activation with bremsstrahlung of an electron linear accelerator and subsequent beta spectroscopy is described. The accuracy of the results was excellent as obtained by analysis of a BCR Reference Material.

  19. Evaluation of antioxidant activity, polyphenolic compounds, amino acids and mineral elements of representative genotypes of Lonicera edulis.

    PubMed

    Sochor, Jiri; Jurikova, Tunde; Pohanka, Miroslav; Skutkova, Helena; Baron, Mojmir; Tomaskova, Lenka; Balla, Stefan; Klejdus, Borivoj; Pokluda, Robert; Mlcek, Jiri; Trojakova, Zuzana; Saloun, Jan

    2014-01-01

    The aim of this study was to evaluate the bioactive substances in 19 berry cultivars of edible honeysuckle (Lonicera edulis). A statistical evaluation was used to determine the relationship between the content of selected bioactive substances and individual cultivars. Regarding mineral elements, the content of sodium was measured using potentiometry and spectrophotometry. The content of selected polyphenolic compounds with high antioxidant activity was determined by a HPLC-UV/ED method. The total amount of polyphenols was determined by the Folin-Ciocalteu method. The antioxidant activity was determined using five methods (DPPH, FRAP, ABTS, FR and DMPD) that differ in their principles. The content of 13 amino acids was determined by ion-exchange chromatography. The experimental results obtained for the different cultivars were evaluated and compared by statistical and bioinformatic methods. A unique feature of this study lies in the exhaustive analysis of the chosen parameters (amino acids, mineral elements, polyphenolic compounds and antioxidant activity) during one growing season. PMID:24853714

  20. Elemental Education.

    ERIC Educational Resources Information Center

    Daniel, Esther Gnanamalar Sarojini; Saat, Rohaida Mohd.

    2001-01-01

    Introduces a learning module integrating three disciplines--physics, chemistry, and biology--and based on four elements: carbon, oxygen, hydrogen, and silicon. Includes atomic model and silicon-based life activities. (YDS)

  1. Transmission eigenvalues

    NASA Astrophysics Data System (ADS)

    Cakoni, Fioralba; Haddar, Houssem

    2013-10-01

    In inverse scattering theory, transmission eigenvalues can be seen as the extension of the notion of resonant frequencies for impenetrable objects to the case of penetrable dielectrics. The transmission eigenvalue problem is a relatively late arrival to the spectral theory of partial differential equations. Its first appearance was in 1986 in a paper by Kirsch who was investigating the denseness of far-field patterns for scattering solutions of the Helmholtz equation or, in more modern terminology, the injectivity of the far-field operator [1]. The paper of Kirsch was soon followed by a more systematic study by Colton and Monk in the context of developing the dual space method for solving the inverse scattering problem for acoustic waves in an inhomogeneous medium [2]. In this paper they showed that for a spherically stratified media transmission eigenvalues existed and formed a discrete set. Numerical examples were also given showing that in principle transmission eigenvalues could be determined from the far-field data. This first period of interest in transmission eigenvalues was concluded with papers by Colton et al in 1989 [3] and Rynne and Sleeman in 1991 [4] showing that for an inhomogeneous medium (not necessarily spherically stratified) transmission eigenvalues, if they existed, formed a discrete set. For the next seventeen years transmission eigenvalues were ignored. This was mainly due to the fact that, with the introduction of various sampling methods to determine the shape of an inhomogeneous medium from far-field data, transmission eigenvalues were something to be avoided and hence the fact that transmission eigenvalues formed at most a discrete set was deemed to be sufficient. In addition, questions related to the existence of transmission eigenvalues or the structure of associated eigenvectors were recognized as being particularly difficult due to the nonlinearity of the eigenvalue problem and the special structure of the associated transmission

  2. Activation of IFN-beta element by IRF-1 requires a posttranslational event in addition to IRF-1 synthesis.

    PubMed Central

    Watanabe, N; Sakakibara, J; Hovanessian, A G; Taniguchi, T; Fujita, T

    1991-01-01

    Expression of the Type I IFN (i.e., IFN-alpha s and IFN-beta) genes is efficiently induced by viruses at the transcriptional level. This induction is mediated by at least two types of positive regulatory elements located in the human IFN-beta gene promoter: (1) the repeated elements which bind both the transcriptional activator IRF-1 and the repressor IRF-2 (IRF-elements; IRF-Es), and (2) the kappa B element (kappa B-E), which binds NF kappa B and is located between the IRF-Es and the TATA box. In this study we demonstrate that a promoter containing synthetic IRF-E, which displays high affinity for the IRFs can be efficiently activated by Newcastle disease virus (NDV). In contrast, such activation was either very weak or nil when cells were treated by IFN-beta or tumor necrosis factor-alpha (TNF-alpha), despite the fact they both efficiently induce de novo synthesis of the short-lived IRF-1 in L929 cells. In fact, efficient activation of the IRF-E apparently requires an event in addition to de novo IRF-1 induction, which can be elicited by NDV even in the presence of protein synthesis inhibitor, cycloheximide. Moreover, efficient activation of the IRF-E by NDV is specifically inhibited by the protein kinase inhibitor, Staurosporin. Hence our results suggest the importance of IRF-1 synthesis and post-translational modification event(s), possibly phosphorylation for the efficient activation of IRF-Es, which are otherwise under negative regulation by IRF-2. Images PMID:1886766

  3. Transmission eigenvalues

    NASA Astrophysics Data System (ADS)

    Cakoni, Fioralba; Haddar, Houssem

    2013-10-01

    In inverse scattering theory, transmission eigenvalues can be seen as the extension of the notion of resonant frequencies for impenetrable objects to the case of penetrable dielectrics. The transmission eigenvalue problem is a relatively late arrival to the spectral theory of partial differential equations. Its first appearance was in 1986 in a paper by Kirsch who was investigating the denseness of far-field patterns for scattering solutions of the Helmholtz equation or, in more modern terminology, the injectivity of the far-field operator [1]. The paper of Kirsch was soon followed by a more systematic study by Colton and Monk in the context of developing the dual space method for solving the inverse scattering problem for acoustic waves in an inhomogeneous medium [2]. In this paper they showed that for a spherically stratified media transmission eigenvalues existed and formed a discrete set. Numerical examples were also given showing that in principle transmission eigenvalues could be determined from the far-field data. This first period of interest in transmission eigenvalues was concluded with papers by Colton et al in 1989 [3] and Rynne and Sleeman in 1991 [4] showing that for an inhomogeneous medium (not necessarily spherically stratified) transmission eigenvalues, if they existed, formed a discrete set. For the next seventeen years transmission eigenvalues were ignored. This was mainly due to the fact that, with the introduction of various sampling methods to determine the shape of an inhomogeneous medium from far-field data, transmission eigenvalues were something to be avoided and hence the fact that transmission eigenvalues formed at most a discrete set was deemed to be sufficient. In addition, questions related to the existence of transmission eigenvalues or the structure of associated eigenvectors were recognized as being particularly difficult due to the nonlinearity of the eigenvalue problem and the special structure of the associated transmission

  4. AQUIFER TRANSMISSIVITY

    EPA Science Inventory

    Evaluation of groundwater resources requires the knowledge of the capacity of aquifers to store and transmit ground water. This requires estimates of key hydraulic parameters, such as the transmissivity, among others. The transmissivity T (m2/sec) is a hydrauli...

  5. The level of selenium and some other trace elements in different Libyan arable soils using instrumental neutron activation analysis.

    PubMed

    El-Ghawi, U M; Al-Fakhri, S M; Al-Sadeq, A A; Bejey, M M; Doubali, K K

    2007-10-01

    Elemental analysis of soils from two different arable regions in Libya was carried out to measure the level of many trace elements. Instrumental neutron activation analysis was used for the determination of 10 elements, viz., (Ba, Ce, Co, Cr, Cs, Fe, Sc, Se, Th, and Zn), using their long-lived radionuclides. The accuracy of the measurements has been evaluated by analyzing two IAEA soil reference materials: IAEA Soil-7 and IAEA leak sediment SL-1; precision has been estimated by triplicate analysis of the sample and that of the reference material. Irradiations were carried out at the Tajura Research Center reactor, at 5-MW power level. It is clear that in the Libyan soil selenium concentration is somewhat lower than in other countries. The results show that trace metal concentrations in Libyan clay surface soil are higher than the sandy soil. PMID:17914223

  6. Determination of thorium and other select trace elements in human tissues by neutron activation analysis

    SciTech Connect

    Glover, S.E.; Grimm, C.A.; Filby, R.H.

    1997-12-01

    Iyengar pointed out the significance of multidisciplinary approaches to biological trace element research and the problems that may be associated with much of the early trace element data (until the early 1970s). Problems identified included the analysis of spurious samples (e.g., hair) based on their availability with no consideration of the biological basis for the investigations and the uncontrolled collection of biological samples by investigators unable to assess the biological integrity of the sample and inadequate quality assurance/quality control. A significant inadequacy is that many trace element analysis studies have been performed on biopsies or samples that may not be representative of the whole organ, or that distribution data have been derived from pooled analyses of organs from many individuals.

  7. A piezolaminated composite degenerated shell finite element for active control of structures with distributed piezosensors and actuators

    NASA Astrophysics Data System (ADS)

    Balamurugan, V.; Narayanan, S.

    2008-06-01

    potential difference between the top and bottom surfaces of the piezoelectric layer. Few case studies of composite general shells with piezoelectric sensors and actuators have been considered by modeling them with the above elements and the active vibration control performance has been studied using linear quadratic Gaussian (LQG) control.

  8. Elemental analysis of granite by instrumental neutron activation analysis (INAA) and X-ray fluorescence analysis (XRF).

    PubMed

    El-Taher, A

    2012-01-01

    The instrumental neutron activation analysis technique (INAA) was used for qualitative and quantitative analysis of granite samples collected from four locations in the Aswan area in South Egypt. The samples were prepared together with their standards and simultaneously irradiated in a neutron flux of 7×10(11)n/cm(2)s in the TRIGA Mainz research reactor. Gamma-ray spectra from an hyper-pure germanium detector were analyzed. The present study provides the basic data of elemental concentrations of granite rocks. The following elements have been determined Na, Mg, K, Fe, Mn, Sc, Cr, Ti, Co, Zn, Ga, Rb, Zr, Nb, Sn, Ba, Cs, La, Ce, Nd, Sm, Eu, Yb, Lu, Hf, Ta, Th and U. The X-ray fluorescence (XRF) was used for comparison and to detect elements, which can be detected only by XRF such as F, S, Cl, Co, Cu, Mo, Ni, Pb, Se and V. The data presented here are our contribution to understanding the elemental composition of the granite rocks. Because there are no existing databases for the elemental analysis of granite, our results are a start to establishing a database for the Egyptian granite. It is hoped that the data presented here will be useful to those dealing with geochemistry, granite chemistry and related fields. PMID:21992845

  9. Compartmentalization of trace elements in guinea pig tissues by INAA (instrumental neutron activation analysis) and AAS (atomic absorption spectroscopy)

    SciTech Connect

    Chatt, A.; Holzbecher, J.; Katz, S.A.

    1988-01-01

    Human scalp hair analysis has received considerable attention from a variety of disciplines over the last 20 yr or so. Trace element levels of hair have been used in environmental, epidemiological, forensic, nutritional, predictive, and preventive medicine studies. There still exist confusion, skepticism, and controversy, however, among the experts as well as lay persons in the interpretation of hair trace element data. Much of the criticism stems from the lack of quantitative and reliable data on the ability of hair to accurately reflect dose-response relationships. To better define the significance or hair trace element levels (under the auspices of the International Atomic Energy Agency), the authors have undertaken a controlled set of animal experiments in which trace element levels in hair and other tissues have been measured after a mild state of systemic intoxication by chronic, low-does exposure to cadmium and selenium. Instrumental neutron activation analysis (INAA) and atomic absorption spectroscopy (AAS) methods have been developed for the determination of several elements with a high degree of precision and accuracy.

  10. Characterization of a putative cis-regulatory element that controls transcriptional activity of the pig uroplakin II gene promoter

    SciTech Connect

    Kwon, Deug-Nam; Park, Mi-Ryung; Park, Jong-Yi; Cho, Ssang-Goo; Park, Chankyu; Oh, Jae-Wook; Song, Hyuk; Kim, Jae-Hwan; Kim, Jin-Hoi

    2011-07-01

    Highlights: {yields} The sequences of -604 to -84 bp of the pUPII promoter contained the region of a putative negative cis-regulatory element. {yields} The core promoter was located in the 5F-1. {yields} Transcription factor HNF4 can directly bind in the pUPII core promoter region, which plays a critical role in controlling promoter activity. {yields} These features of the pUPII promoter are fundamental to development of a target-specific vector. -- Abstract: Uroplakin II (UPII) is a one of the integral membrane proteins synthesized as a major differentiation product of mammalian urothelium. UPII gene expression is bladder specific and differentiation dependent, but little is known about its transcription response elements and molecular mechanism. To identify the cis-regulatory elements in the pig UPII (pUPII) gene promoter region, we constructed pUPII 5' upstream region deletion mutants and demonstrated that each of the deletion mutants participates in controlling the expression of the pUPII gene in human bladder carcinoma RT4 cells. We also identified a new core promoter region and putative negative cis-regulatory element within a minimal promoter region. In addition, we showed that hepatocyte nuclear factor 4 (HNF4) can directly bind in the pUPII core promoter (5F-1) region, which plays a critical role in controlling promoter activity. Transient cotransfection experiments showed that HNF4 positively regulates pUPII gene promoter activity. Thus, the binding element and its binding protein, HNF4 transcription factor, may be involved in the mechanism that specifically regulates pUPII gene transcription.

  11. [Neutron activation analysis of human hair--multivariate analysis of factors influencing on trace element contents in hair-- (author's transl)].

    PubMed

    Imahori, A; Fukushima, I

    1980-06-01

    As a part of IAEA research project, "Activation analysis of hair as an indicator of contamination of man by environmental trace element pollutants", a survey was carried out to elucidate the levels of various trace element concentrations in hair of local population in the Tokyo Metropolitan areas, by applying instrumental neutron activation analysis. A total of 202 scalp hair samples were collected from the inhabitants classified by sex and five age classes. Irradiation was made in the Rikkyo University 100 kW TRIGA MARK-II reactor. Using several combinations of irradiation time, cooling time and counting time, forty elements were determined. The relationship between several trace element contents in hair and such factors as sex, age class, hair treatment, smoking habit and dental treatment, was analyzed by using the method of multiple regression. It was shown that (1) Hair treatment had a predominant effect on the contents of bromine, magnesium and calcium in hair, (2) Aging and smoking contributed increasing mercury content in hair, and hair treatment acted reversely. PMID:7208973

  12. Identification and characterization of the first active endogenous transposable element in soybean

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In soybean [Glycine max (L.) Merr.], W4 is one of the loci that control anthocyanin biosynthesis in flowers and hypocotyls. A putative transposable element was suggested to reside within or adjacent to this locus in the mutable T322 line resulting in the w4-m allele. We have shown that the W4 locu...

  13. Controls on Fe(II)-Activated Trace Element Release from Goethite and Hematite

    SciTech Connect

    Frierdich, Andrew J.; Catalano, Jeffrey G.

    2012-03-26

    Electron transfer and atom exchange (ETAE) between aqueous Fe(II) and Fe(III) oxides induces surface growth and dissolution that affects trace element fate and transport. We have recently demonstrated Ni(II) cycling through goethite and hematite (adsorbed Ni incorporates into the mineral structure and preincorporated Ni releases to solution) during Fe(II)-Fe(III) ETAE. However, the chemical parameters affecting net trace element release remain unknown. Here, we examine the chemical controls on Ni(II) and Zn(II) release from Ni- and Zn-substituted goethite and hematite during reaction with Fe(II). Release follows a rate law consistent with surface reaction limited mineral dissolution and suggests that release occurs near sites of Fe(III) reductive dissolution during Fe(II)-Fe(III) ETAE. Metal substituent type affects reactivity; Zn release is more pronounced from hematite than goethite, whereas the opposite trend occurs for Ni. Buildup of Ni or Zn in solution inhibits further release but this resumes upon fluid exchange, suggesting that sustained release is possible under flow conditions. Mineral and aqueous Fe(II) concentrations as well as pH strongly affect sorbed Fe(II) concentrations, which directly control the reaction rates and final metal concentrations. Our results demonstrate that structurally incorporated trace elements are mobilized from iron oxides into fluids without abiotic or microbial net iron reduction. Such release may affect micronutrient availability, contaminant transport, and the distribution of redox-inactive trace elements in natural and engineered systems.

  14. Interplanetary dust - Trace element analysis of individual particles by neutron activation

    NASA Technical Reports Server (NTRS)

    Ganapathy, R.; Brownlee, D. E.

    1979-01-01

    Although micrometeorites of cometary origin are thought to be the dominant component of interplanetary dust, it has never been possible to positively identify such micrometer-sized particles. Two such particles have been identified as definitely micrometeorites since their abundances of volatile and nonvolatile trace elements closely match those of primitive solar system material.

  15. The hobo transposable element has transposase-dependent and -independent excision activity in drosophilid species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mobility of the hobo transposable element was determined for several strains of Drosophila melanogaster and several Drosophila species. Mobility was assessed by use of an in vivo transient assay in the soma of developing embryos, which monitored hobo excision from injected indicator plasmids. Excisi...

  16. Jordan, an active Volvox transposable element similar to higher plant transposons.

    PubMed Central

    Miller, S M; Schmitt, R; Kirk, D L

    1993-01-01

    We have isolated a 1595-bp transposable element from the multicellular green alga Volvox carteri following its insertion into the nitrate reductase (nitA) locus. This element, which we have named Jordan, has short (12-bp) terminal inverted repeats and creates a 3-bp target site duplication, like some higher plant transposons of the classic type. Contained within the first 200 bp of one end of the element are 55-bp inverted repeats, one of which begins with the terminal inverted repeat. Revertants of the transposon insertion into the nitA locus were obtained at a rate of approximately 10(-4) per Volvox embryo per generation. In each revertant examined, all transposon sequences were completely excised, but footprints containing both sets of duplicated bases, in addition to three to nine extra bases, were left behind. Jordan contains no significant open reading frames and so appears to be nonautonomous. DNA gel blot analysis indicates that Jordan is a member of a large family of homologous elements in the Volvox genome. We have isolated and characterized several of these homologs and found that they contain terminal very similar to those of Jordan. Efforts to utilize Jordan and its homologs as tools to tag and clone developmentally interesting genes of Volvox are discussed. PMID:8400878

  17. Testosterone activates mitogen-activated protein kinase and the cAMP response element binding protein transcription factor in Sertoli cells

    PubMed Central

    Fix, Charity; Jordan, Cynthia; Cano, Patricia; Walker, William H.

    2004-01-01

    The androgen testosterone is essential for the Sertoli cell to support the maturation of male germ cells and the production of spermatozoa (spermatogenesis). In the classical view of androgen action, binding of androgen to the intracellular androgen receptor (AR) produces a conformational change in AR such that the receptor–steroid complex has high affinity for specific DNA regulatory elements and is able to stimulate gene transcription. Here, we demonstrate that testosterone can act by means of an alternative, rapid, and sustainable mechanism in Sertoli cells that is independent of AR–DNA interactions. Specifically, the addition of physiological levels of testosterone to Sertoli cells stimulates the mitogen-activated protein kinase signaling pathway and causes phosphorylation of the cAMP response element binding protein transcription factor on serine 133, a modification known to be required for Sertoli cells to support spermatogenesis. Androgen-mediated activation of mitogen-activated protein kinase and cAMP response element binding protein occurs within 1 min, extends for at least 12 h and requires AR. Furthermore, androgen induces endogenous cAMP response element binding protein-mediated transcription in Sertoli cells. These newly identified mechanisms of androgen action in Sertoli cells suggest new targets for developing male contraceptive agents. PMID:15263086

  18. An electrically tunable depth-of-field endoscope using a liquid crystal lens as an active focusing element

    NASA Astrophysics Data System (ADS)

    Chen, Hung-Shan; Chen, Ming-Syuan; Lin, Yi-Hsin

    2013-09-01

    An electrically tunable depth-of-field (DOF) endoscope using a liquid crystal lens (LC lens) as an active focusing element is demonstrated. The optical mechanism of the electrically-tunable DOF endoscope adopting a two-mode switching LC lens is introduced. The two-mode switching LC lens provides not only a positive lens power but also a negative lens power. Therefore, we could extend the range of DOF originally from 27 mm ~ 55 mm to 12.4 mm ~ 76.4 mm by using the two-mode switching LC lens as an active focusing element. The detail derivations of the optical mechanism of the endoscopic system adopting a LC lens are invistgated. The more detail experimental results are demonstrated. We believe this study can provide a more detail understanding of an endoscopic system adopting a tunable focusing lens.

  19. Final Report: Main Group Element Chemistry in Service of Hydrogen Storage and Activation

    SciTech Connect

    David A. Dixon; Anthony J. Arduengo, III

    2010-09-30

    goal was met in terms of reducing the number of costly experiments and helping to focus the experimental effort on the potentially optimal targets. We have used computational chemistry approaches to predict the thermodynamic properties of a wide range of compounds containing boron, nitrogen, hydrogen, and other elements as appropriate including carbon. These calculations were done in most cases with high level molecular orbital theory methods that have small error bars on the order of ± 1 to 2 kcal/mol. The results were used to benchmark more approximate methods such as density functional theory for larger systems and for database development. We predicted reliable thermodynamics for thousands of compounds for release and regeneration schemes to aid/guide materials design and process design and simulation. These are the first reliable computed values for these compounds and for many represent the only available values. Overall, the computational results have provided us with new insights into the chemistry of main group and organic-base chemical hydrogen systems from the release of hydrogen to the regeneration of spent fuel. A number of experimental accomplishments were also made in this project. The experimental work on hydrogen storage materials centered on activated polarized σ- or π-bonded frameworks that hold the potential for ready dihydrogen activation, uptake, and eventually release. To this end, a large number of non-traditional valence systems including carbenes, cyanocarbons, and C-B and and B-N systems were synthesized and examined. During the course of these studies an important lead arose from the novel valency of a class of stable organic singlet bi-radical systems. A synthetic strategy to an “endless” hydrogen storage polymer has been developed based on our cyanocarbon chemistry. A key issue with the synthetic efforts was being able to link the kinetics of release with the size of the substituents as it was difficult to develop a low molecular

  20. Controlled trial comparing prednisolone with an elemental diet plus non-absorbable antibiotics in active Crohn's disease.

    PubMed

    Saverymuttu, S; Hodgson, H J; Chadwick, V S

    1985-10-01

    In a randomised clinical trial, patients with moderately active Crohn's disease received either prednisolone 0.5 mg/kg/day plus a normal diet, or an elemental diet plus oral framycetin, colistin and nystatin. Patients were assessed using the Crohn's disease activity index (CDAI), ESR, and faecal granulocyte excretion quantified by 111In-autologous leucocytes. Five patients were intolerant of the elemental diet plus antibiotics and were withdrawn from the trial within 72 hours. Sixteen patients completed 10 days treatment on each regime. Fifteen of 16 patients on elemental diet plus antibiotics and all 16 patients on prednisolone improved with marked, but statistically indistinguishable falls in CDAI, ESR, and faecal granulocyte excretion between the two groups. Thus a regime decreasing the intraluminal concentration of bacteria and complex food molecules, was associated with rapid improvement in activity of Crohn's disease. This suggests that these intraluminal factors play a role in maintaining inflammation and that their removal or alteration offers an approach to management. PMID:3902590

  1. Application of artificial neural network in precise prediction of cement elements percentages based on the neutron activation analysis

    NASA Astrophysics Data System (ADS)

    Eftekhari Zadeh, E.; Feghhi, S. A. H.; Roshani, G. H.; Rezaei, A.

    2016-05-01

    Due to variation of neutron energy spectrum in the target sample during the activation process and to peak overlapping caused by the Compton effect with gamma radiations emitted from activated elements, which results in background changes and consequently complex gamma spectrum during the measurement process, quantitative analysis will ultimately be problematic. Since there is no simple analytical correlation between peaks' counts with elements' concentrations, an artificial neural network for analyzing spectra can be a helpful tool. This work describes a study on the application of a neural network to determine the percentages of cement elements (mainly Ca, Si, Al, and Fe) using the neutron capture delayed gamma-ray spectra of the substance emitted by the activated nuclei as patterns which were simulated via the Monte Carlo N-particle transport code, version 2.7. The Radial Basis Function (RBF) network is developed with four specific peaks related to Ca, Si, Al and Fe, which were extracted as inputs. The proposed RBF model is developed and trained with MATLAB 7.8 software. To obtain the optimal RBF model, several structures have been constructed and tested. The comparison between simulated and predicted values using the proposed RBF model shows that there is a good agreement between them.

  2. Hypoxia-induced endothelial NO synthase gene transcriptional activation is mediated through the tax-responsive element in endothelial cells.

    PubMed

    Min, Jiho; Jin, Yoon-Mi; Moon, Je-Sung; Sung, Min-Sun; Jo, Sangmee Ahn; Jo, Inho

    2006-06-01

    Although hypoxia is known to induce upregulation of endothelial NO synthase (eNOS) gene expression, the underlying mechanism is largely unclear. In this study, we show that hypoxia increases eNOS gene expression through the binding of phosphorylated cAMP-responsive element binding (CREB) protein (pCREB) to the eNOS gene promoter. Hypoxia (1% O2) increased both eNOS expression and NO production, peaking at 24 hours, in bovine aortic endothelial cells, and these increases were accompanied by increases in pCREB. Treatment with the protein kinase A inhibitor H-89 or transfection with dominant-negative inhibitor of CREB reversed the hypoxia-induced increases in eNOS expression and NO production, with concomitant inhibition of the phosphorylation of CREB induced by hypoxia, suggesting an involvement of protein kinase A/pCREB-mediated pathway. To map the regulatory elements of the eNOS gene responsible for pCREB binding under hypoxia, we constructed an eNOS gene promoter (-1600 to +22 nucleotides) fused with a luciferase reporter gene [pGL2-eNOS(-1600)]. Hypoxia (for 24-hour incubation) increased the promoter activity by 2.36+/-0.18-fold in the bovine aortic endothelial cells transfected with pGL2-eNOS(-1600). However, progressive 5'-deletion from -1600 to -873 completely attenuated the hypoxia-induced increase in promoter activity. Electrophoretic mobility shift, anti-pCREB antibody supershift, and site-specific mutation analyses showed that pCREB is bound to the Tax-responsive element (TRE) site, a cAMP-responsive element-like site, located at -924 to -921 of the eNOS promoter. Our data demonstrate that the interaction between pCREB and the Tax-responsive element site within the eNOS promoter may represent a novel mechanism for the mediation of hypoxia-stimulated eNOS gene expression. PMID:16651461

  3. Overview of past and current activities on fuels for fast reactors at the Institute for Transuranium Elements

    NASA Astrophysics Data System (ADS)

    Fernandez, A.; McGinley, J.; Somers, J.; Walter, M.

    2009-07-01

    Nuclear energy has the potential to provide a secure and sustainable electricity supply at a competitive price and to make a significant contribution to the reduction of greenhouse gas emissions. The renewal of interest in fast neutron spectra reactors to meet more ambitious sustainable development criteria (i.e., resource maximisation and waste minimisation), opens a favourable framework for R&D activities in this area. The Institute for Transuranium Elements has extensive experience in the fabrication, characterization and irradiation testing (Phénix, Dounreay, Rapsodie) of fast reactor fuels, in oxide, nitride and carbide forms. An overview of these past and current activities on fast reactor fuels is presented.

  4. Surface-active element effects on the shape of GTA, laser, and electron-beam welds

    SciTech Connect

    Heiple, C.R.; Roper, J.R.; Stagner, R.T.; Aden, R.J.

    1983-03-01

    Laser and electron-beam welds were passed across selenium-doped zones in 21-6-9 stainless steel. The depth/width (d/w) ratio of a defocused laser weld with a weld pool shape similar to a GTA weld increased by over 200% in a zone where 66 ppm selenium had been added. Smaller increases were observed in selenium-doped zones for a moderately defocused electron beam weld with a higher d/w ratio in undoped base metal. When laser or electron beam weld penetration was by a keyhole mechanism, no change in d/w ratio occurred in selenium-doped zones. The results confirm the surface-tension-driven fluid-flow model for the effect of minor elements on GTA weld pool shape. Other experimental evidence bearing on the effect of minor elements on GTA weld penetration is summarized.

  5. Nezha, a novel active miniature inverted-repeat transposable element in cyanobacteria

    SciTech Connect

    Zhou Fengfeng; Tran Thao; Xu Ying

    2008-01-25

    Miniature inverted-repeat transposable elements (MITEs) were first identified in plants and exerted extensive proliferations throughout eukaryotic and archaeal genomes. But very few MITEs have been characterized in bacteria. We identified a novel MITE, called Nezha, in cyanobacteria Anabaena variabilis ATCC 29413 and Nostoc sp. PCC 7120. Nezha, like most previously known MITEs in other organisms, is small in size, non-coding, carrying TIR and DR signals, and of potential to form a stable RNA secondary structure, and it tends to insert into A+T-rich regions. Recent transpositions of Nezha were observed in A. variabilis ATCC 29413 and Nostoc sp. PCC 7120, respectively. Nezha might have proliferated recently with aid from the transposase encoded by ISNpu3-like elements. A possible horizontal transfer event of Nezha from cyanobacteria to Polaromonas JS666 is also observed.

  6. Trace-element analysis of 1000 environmental samples per year using instrumental neutron activation analysis

    NASA Technical Reports Server (NTRS)

    Sheibley, D. W.

    1974-01-01

    The technology and methods developed at the Plum Brook Reactor to analyze 1000 samples per year and report data on as many as 56 elements are described. The manpower for the complete analysis of 20 to 24 samples per week required only 3 to 3.5 hours per sample. The solutions to problems encountered in sample preparation, irradiation, and counting are discussed. The automation of data reduction is described. Typical data on various sample matrices are presented.

  7. A consensus insulin response element is activated by an Ets-related transcription factor.

    PubMed

    Jacob, K K; Ouyang, L; Stanley, F M

    1995-11-17

    Insulin increases expression of somatostatin-chloramphenicol acetyltransferase (CAT) constructs 10-fold and thymidine kinase-CAT constructs 5-fold in GH4 cells. These responses are similar to our previously reported data on insulin-increased prolactin-CAT expression. They are also observed in HeLa cells and are thus not cell type specific. The evidence suggests that the insulin responsiveness of these genes is mediated by an Ets-related transcription factor. First, linker-scanning mutations and/or deletions of the prolactin, somatostatin, and thymidine kinase promoters suggest that their insulin responsiveness is mediated by the sequence CGGA. This sequence is identical with the response element of the Ets-related transcription factors. Second, CGGA-containing sequences placed at -88 in the delta MTV-CAT reporter plasmid conferred insulin responsiveness to the mammary tumor virus promoter. Third, expression of the DNA-binding domain of c-Ets-2, which acts by blocking effects mediated by Ets-related transcription factors, inhibits the response of these promoters to insulin. Finally, the Ets-related proteins Sap and Elk-1 bind to the prolactin, somatostatin, and thymidine kinase insulin-response elements. An Ets-like element was found in all insulin-sensitive promoters examined and may serve a similar function in those promoters. PMID:7499246

  8. Size-spectra of trace elements in urban aerosol particles by instrumental neutron activation analysis

    SciTech Connect

    Ondov, J.M.; Divita, F. Jr.; Suarez, A.

    1994-12-31

    Knowledge of composition and size of atmospheric aerosol particles is needed to elucidate their sources, atmospheric transformation processes, contributions to visibility reduction, and respiratory and environmental deposition. In a previous communication, we described size spectra and hygroscopic growth of arsenic, selenium, antimony, and zinc in College Park, Maryland, an urban, nonindustrial area located near Washington, D.C., wherein, concentrations of these elements are influenced largely by sulfate-containing aerosol transported from the Ohio River valley region, more than 200 km west of the area, and local coal utility plants and incinerators located 20 to 50 km from the sampling site. At College Park, mass median aerodynamic diameters (mmad) versus relative humidity (RH) data for these elements fell along different curves for samples influenced by local and distant aerosols; i.e., the curve for distant sources lay below the curve for local sources, at larger mmads for the same RH. In this paper we discuss size spectra, distribution parameters, and hygroscopic growth of aerosol particles bearing trace elements in aerosol collected in Camden, New Jersey, a heavily industrial area in which major sources, including an antimony roaster and municipal incinerator, lie in close proximity (i.e., 5 to 15 km) to the site.

  9. Nuclear Thermal Rocket Element Environmental Simulator (NTREES) Phase II Upgrade Activities

    NASA Technical Reports Server (NTRS)

    Emrich, William J.; Moran, Robert P.; Pearson, J. Bose

    2013-01-01

    To support the on-going nuclear thermal propulsion effort, a state-of-the-art non nuclear experimental test setup has been constructed to evaluate the performance characteristics of candidate fuel element materials and geometries in representative environments. The facility to perform this testing is referred to as the Nuclear Thermal Rocket Element Environment Simulator (NTREES). This device can simulate the environmental conditions (minus the radiation) to which nuclear rocket fuel components will be subjected during reactor operation. Test articles mounted in the simulator are inductively heated in such a manner so as to accurately reproduce the temperatures and heat fluxes which would normally occur as a result of nuclear fission and would be exposed to flowing hydrogen. Initial testing of a somewhat prototypical fuel element has been successfully performed in NTREES and the facility has now been shutdown to allow for an extensive reconfiguration of the facility which will result in a significant upgrade in its capabilities. Keywords: Nuclear Thermal Propulsion, Simulator

  10. Discovery and analysis of an active long terminal repeat-retrotransposable element in Aspergillus oryzae.

    PubMed

    Jie Jin, Feng; Hara, Seiichi; Sato, Atsushi; Koyama, Yasuji

    2014-01-01

    Wild-type Aspergillus oryzae RIB40 contains two copies of the AO090005001597 gene. We previously constructed A. oryzae RIB40 strain, RKuAF8B, with multiple chromosomal deletions, in which the AO090005001597 copy number was found to be increased significantly. Sequence analysis indicated that AO090005001597 is part of a putative 6,000-bp retrotransposable element, flanked by two long terminal repeats (LTRs) of 669 bp, with characteristics of retroviruses and retrotransposons, and thus designated AoLTR (A. oryzae LTR-retrotransposable element). AoLTR comprised putative reverse transcriptase, RNase H, and integrase domains. The deduced amino acid sequence alignment of AoLTR showed 94% overall identity with AFLAV, an A. flavus Tf1/sushi retrotransposon. Quantitative real-time RT-PCR showed that AoLTR gene expression was significantly increased in the RKuAF8B, in accordance with the increased copy number. Inverse PCR indicated that the full-length retrotransposable element was randomly integrated into multiple genomic locations. However, no obvious phenotypic changes were associated with the increased AoLTR gene copy number. PMID:24646755

  11. Binding of TFIIIC to SINE Elements Controls the Relocation of Activity-Dependent Neuronal Genes to Transcription Factories

    PubMed Central

    Crepaldi, Luca; Policarpi, Cristina; Coatti, Alessandro; Sherlock, William T.; Jongbloets, Bart C.; Down, Thomas A.; Riccio, Antonella

    2013-01-01

    In neurons, the timely and accurate expression of genes in response to synaptic activity relies on the interplay between epigenetic modifications of histones, recruitment of regulatory proteins to chromatin and changes to nuclear structure. To identify genes and regulatory elements responsive to synaptic activation in vivo, we performed a genome-wide ChIPseq analysis of acetylated histone H3 using somatosensory cortex of mice exposed to novel enriched environmental (NEE) conditions. We discovered that Short Interspersed Elements (SINEs) located distal to promoters of activity-dependent genes became acetylated following exposure to NEE and were bound by the general transcription factor TFIIIC. Importantly, under depolarizing conditions, inducible genes relocated to transcription factories (TFs), and this event was controlled by TFIIIC. Silencing of the TFIIIC subunit Gtf3c5 in non-stimulated neurons induced uncontrolled relocation to TFs and transcription of activity-dependent genes. Remarkably, in cortical neurons, silencing of Gtf3c5 mimicked the effects of chronic depolarization, inducing a dramatic increase of both dendritic length and branching. These findings reveal a novel and essential regulatory function of both SINEs and TFIIIC in mediating gene relocation and transcription. They also suggest that TFIIIC may regulate the rearrangement of nuclear architecture, allowing the coordinated expression of activity-dependent neuronal genes. PMID:23966877

  12. Dynamics and distributed control of geometrically nonlinear active piezothermoelastic structronic systems using the finite element technique

    NASA Astrophysics Data System (ADS)

    Wang, Dongwei

    Recent research and development of adaptive materials, smart structures and structronic systems have opened a new era to aerospace and structural engineering. Effective control of these intelligent structures and systems using piezoelectric materials can enhance operation precision, accuracy and reliability. This research is to investigate the dynamics, vibration sensing and control of the geometrically nonlinear distributed piezothermoelastic structures subjected to the combined mechanical, electrical, and thermal excitations by the finite element method. Based on the layerwise constant shear angle theory, the curved hexahedral and triangular piezothermoelastic shell elements are proposed. The generic finite element formulations for vibration sensing and control analysis of nonlinear piezothermoelastic shell structures are derived based on the total Lagrangian virtual work principle. Dynamic system equations, equations of electric potential outputs, and feedback control forces are derived and discussed. The modified Newton-Raphson method is used for efficient dynamic analysis of the nonlinear piezothermoelastic structural systems. Different control algorithms are implemented. The feedback control forces generated from the distributed actuator can effectively enhance system damping and suppress system vibration via proper feedback control techniques. Comprehensive case studies are performed to evaluate the accuracy of the newly developed piezothermoelastic shell elements and to validate the finite element code. Dynamics and vibration sensing/control of nonlinear piezothermoelastic beam and plate systems are analyzed. Distributed piezoelectric films placed on the beam and plate structures respectively serving as sensor and actuators are discussed. The effect of geometric nonlinearity is to stiffen the beam and plate structures and the control effect becomes worse when geometric nonlinearity becomes significant. It shows that negative velocity control scheme is

  13. A Novel Peroxisome Proliferator Response Element Modulates Hepatic Low Density Lipoprotein Receptor Gene Transcription in Response to PPARδ Activation

    PubMed Central

    Shende, Vikram R.; Singh, Amar Bahadur; Liu, Jingwen

    2016-01-01

    The hepatic expression of LDLR gene is regulated primarily at the transcriptional level by a sterol-regulatory element (SRE) in its proximal promoter region which is the site of action of SRE-binding protein 2 (SREBP2). However whether additional cis-regulatory elements contribute to LDLR transcription has not been fully explored. We investigated the function of a putative PPAR-response element (PPRE) sequence motif located at −768 to −752 bases upstream of the transcription start site of human LDLR gene in response to PPARδ activation. Promoter luciferase reporter analyses showed that treating HepG2 cells with PPARδ agonist L165041 markedly increased the activity of a full-length LDLR promoter construct (pLDLR-1192) without any effects on the shorter promoter reporter pLDLR-234 that contains only the core regulatory elements SRE-1 and SP1 sites. Importantly, mutation of the PPRE sequence greatly attenuated the induction of the full-length LDLR promoter activity by L165041 without affecting rosuvastatin mediated transactivation. Electrophoretic mobility shift and chromatin immunoprecipitation assays further confirmed the binding of PPARδ to the LDLR-PPRE site. Treating HepG2 cells with L165041 elevated the mRNA and protein expressions of LDLR without affecting the LDLR mRNA decay rate. The induction of LDLR expression by PPARδ agonist was further observed in liver tissue of mice and hamsters treated with L165041. Altogether, our studies identify a novel PPRE-mediated regulatory mechanism for LDLR transcription and suggest that combined treatment of statin with PPARδ agonists may have advantageous effects on LDLR expression. PMID:26443862

  14. Assessment and Accommodation of Thermal Expansion of the Internal Active Thermal Control System Coolant During Launch to On-Orbit Activation of International Space Station Elements

    NASA Technical Reports Server (NTRS)

    Edwards, J. Darryl; Ungar, Eugene K.; Holt, James M.; Turner, Larry D. (Technical Monitor)

    2001-01-01

    The International Space Station (ISS) employs an Internal Active Thermal Control System (IATCS) comprised of several single-phase water coolant loops. These coolant loops are distributed throughout the ISS pressurized elements. The primary element coolant loops (i.e., US Laboratory module) contain a fluid accumulator to accommodate thermal expansion of the system. Other element coolant loops are parasitic (i.e., Airlock), have no accumulator, and require an alternative approach to insure that the system Maximum Design Pressure (MDP) is not exceeded during the Launch to Activation phase. During this time the element loop is a stand alone closed individual system. The solution approach for accommodating thermal expansion was affected by interactions of system components and their particular limitations. The mathematical solution approach was challenged by the presence of certain unknown or not readily obtainable physical and thermodynamic characteristics of some system components and processes. The purpose of this paper is to provide a brief description of a few of the solutions that evolved over time, a novel mathematical solution to eliminate some of the unknowns or derive the unknowns experimentally, and the testing and methods undertaken.

  15. Assessment and Accommodation of Thermal Expansion of the Internal Active Thermal Control System Coolant During Launch to On-Orbit Activation of International Space Station Elements

    NASA Technical Reports Server (NTRS)

    Edwards, Darryl; Ungar, Eugene K.; Holt, James M.

    2002-01-01

    The International Space Station (ISS) employs an Internal Active Thermal Control System (IATCS) comprised of several single-phase water coolant loops. These coolant loops are distributed throughout the ISS pressurized elements. The primary element coolant loops (i.e. U.S. Laboratory module) contain a fluid accumulator to accomodate thermal expansion of the system. Other element coolant loops are parasitic (i.e. Airlock), have no accumulator, and require an alternative approach to insure that the system maximum design pressure (MDP) is not exceeded during the Launch to Activation (LTA) phase. During this time the element loops is a stand alone closed system. The solution approach for accomodating thermal expansion was affected by interactions of system components and their particular limitations. The mathematical solution approach was challenged by the presence of certain unknown or not readily obtainable physical and thermodynamic characteristics of some system components and processes. The purpose of this paper is to provide a brief description of a few of the solutions that evolved over time, a novel mathematical solution to eliminate some of the unknowns or derive the unknowns experimentally, and the testing and methods undertaken.

  16. Activation of Tag1 transposable elements in Arabidopsis dedifferentiating cells and their regulation by CHROMOMETHYLASE 3-mediated CHG methylation.

    PubMed

    Khan, Asif; Yadav, Narendra Singh; Morgenstern, Yaakov; Zemach, Assaf; Grafi, Gideon

    2016-10-01

    Dedifferentiation, that is, the acquisition of stem cell-like state, commonly induced by stress (e.g., protoplasting), is characterized by open chromatin conformation, a chromatin state that could lead to activation of transposable elements (TEs). Here, we studied the activation of the Arabidopsis class II TE Tag1, in which two copies, situated close to each other (near genes) on chromosome 1 are found in Landsberg erecta (Ler) but not in Columbia (Col). We first transformed protoplasts with a construct in which a truncated Tag1 (ΔTag1 non-autonomous) blocks the expression of a reporter gene AtMBD5-GFP and found a relatively high ectopic excision of ΔTag1 accompanied by expression of AtMBD5-GFP in protoplasts derived from Ler compared to Col; further increase was observed in ddm1 (decrease in DNA methylation1) protoplasts (Ler background). Ectopic excision was associated with transcription of the endogenous Tag1 and changes in histone H3 methylation at the promoter region. Focusing on the endogenous Tag1 elements we found low level of excision in Ler protoplasts, which was slightly and strongly enhanced in ddm1 and cmt3 (chromomethylase3) protoplasts, respectively, concomitantly with reduction in Tag1 gene body (GB) CHG methylation and increased Tag1 transcription; strong activation of Tag1 was also observed in cmt3 leaves. Notably, in cmt3, but not in ddm1, Tag1 elements were excised out from their original sites and transposed elsewhere in the genome. Our results suggest that dedifferentiation is associated with Tag1 activation and that CMT3 rather than DDM1 plays a central role in restraining Tag1 activation via inducing GB CHG methylation. PMID:27475038

  17. Changes in grammage, tearing resistance, and water vapor transmission rate of active paper incorporated with Cinnamaldehyde during storage at various temperatures

    NASA Astrophysics Data System (ADS)

    Manuhara, G. J.; Khasanah, L. U.; Utami, R.

    2016-02-01

    Antimicrobial properties of active paper packaging incorporated with cinnamaldehyde and its application in the storage of agricultural products had been studied. However, changes in grammage, tear resistance and water vapor transmission rate (WVTR) of the active paper during storage is not yet known, whereas it is important to provide consideration in application of the active paper. This study aims to determine the changes in those physical properties during storage (20 days) at various temperatures (10, 20, 25, 30, and 40 °C). The grammage and WVTR of the active paper decreased as increase in storage time and temperature, while the tearing resistance increased as storage time. Higher temperature caused slower increase in tearing resistance, but the results showed fluctuation. The results of Arrhenius plot indicated the activation energy (in kJ/mol) of those physical properties, sorted from the highest to the lowest as follows: 53.6 (grammage), 14.8 (WVTR) and 13.8 (tearing resistance).

  18. Preliminary results of trace elements mobility in soils and plants from the active hydrothermal area of Nisyros island (Greece)

    NASA Astrophysics Data System (ADS)

    Daskalopoulou, Kyriaki; Calabrese, Sergio; Milazzo, Silvia; Brusca, Lorenzo; D'Alessandro, Walter; Kyriakopoulos, Konstantinos; Tassi, Franco; Parello, Francesco

    2014-05-01

    Trace elements, i.e. chemical constituents of rocks with concentration <1000 ppm, play a structural role in the organisms and use proteins as a carrier to their target site. Their toxicity depends on their concentration, speciation and reactions with other elements. In volcanic environments, significant amounts of trace elements discharged from gas emissions, contribute to produce air particulate. Nisyros Island is a stratovolcano located at the South Aegean active Volcanic Arc. Intense hydrothermal activity characterise the Lakki caldera. In particular, the fumaroles located in the craters of Stefanos, Kaminakia, Lofos Dome and the area comprising Phlegeton, Polyvotes Micros and Polyvotes Megalos discharge hydrothermal fluids rich in H2O (91- 99%), SO2 and H2S. Their temperatures are almost 100o C and H2S is highly abundant accounting for 8-26 % of the released dry gas phase. On June 2013, during a multidisciplinary field trip on Nisyros island, 39 samples of top soils and 31 of endemic plants (Cistus Creticus and Salvifolius and Erica Arborea and Manipuliflora) were collected in the caldera area, with the aim to investigate the distribution of concentrations of trace elements related to the contribution of deep originated fluids. Moreover, one sample of plant and soil was collected outside the caldera as local background, for comparison. All the soil samples were powdered avoiding metal contamination and they were extracted twice, using HNO3 + HCl for one extraction (closed microwave digestion) and ultrapure de- ionized water for the other one (leaching extraction). The leaves of plants were gently isolated, dried and powdered for acid microwave extraction (HNO3 + H2O2). All the solutions were analysed for major and trace elements contents by using ionic chromatography (IC) and inductively plasma spectrometry (ICP-MS and ICP-OES). The preliminary results showed high enrichment of many trace elements both in plant and soils respect to the local background, in

  19. Mechanism of optical terahertz-transmission modulation in an organic/inorganic semiconductor interface and its application to active metamaterials.

    PubMed

    Matsui, Tatsunosuke; Takagi, Ryosuke; Takano, Keisuke; Hangyo, Masanori

    2013-11-15

    Terahertz (THz) transmission modulation through copper phthalocyanine (CuPc)-coated Si under various laser light irradiation conditions was investigated using THz time-domain spectroscopy. The charge carrier transfer from Si to CuPc is crucial for photo-induced metallization, and the thickness of the CuPc layer is a critical parameter for achieving high charge carrier density for metallization. Transmission through a split-ring resonator array metamaterial, fabricated on CuPc-coated Si, can be efficiently modulated by laser light irradiation. Our findings may open the way for various types of metamaterials using organic conjugated materials that are suitable for easy device fabrication using printing technologies. PMID:24322092

  20. A discrete element 3' of human immunodeficiency virus 1 (HIV-1) and HIV-2 mRNA initiation sites mediates transcriptional activation by an HIV trans activator

    SciTech Connect

    Jakobovits, A.; Smith, D.H.; Jakobovits, E.B.; Capon, D.J.

    1988-06-01

    An important point of regulation in the reproductive growth and latency of the human and simian immunodeficiency viruses (HIV and SIV, respectively) is provided by virally encoded trans-activators (tat), proteins capable of dramatically increasing viral gene expression. The mechanism of this autostimulatory pathway has remained unclear, however, with substantial effects having been reported at the level of either mRNA accumulation, translational efficiency, or both. The authors' previous findings indicated that trans-activation results primarily from induction of RNA levels but could not distinguish between the roles of transcriptional rate, RNA stabilization, and RNA transport in this event. In addition, the boundaries of tat-responding elements, which would be valuable in elucidating the mode of tat action, are not precisely known. In this study, HIV-1 and HIV-2 long terminal repeat-directed expression was characterized by using in an vitro nuclear transcription assay to clarify this mechanism, and a detailed mutational analysis was undertaken to localize precisely the sequences participating in this process. Two key findings were revealed: an increased transcription rate was the primary event in tat-mediated activation of HIV-1 and HIV-2, and trans-activation was impaired by mutations in two regions, the TATA box and sequences between +19 to +42, a region lacking enhancer activity. These results implicate a discrete 3' regulatory element in the transcriptional activation of the HIVs.

  1. Transcriptional read-through is not sufficient to induce an epigenetic switch in the silencing activity of Polycomb response elements

    PubMed Central

    Erokhin, Maksim; Elizar’ev, Pavel; Parshikov, Aleksander; Schedl, Paul; Georgiev, Pavel; Chetverina, Darya

    2015-01-01

    In Drosophila, Polycomb (PcG) and Trithorax (TrxG) group proteins are assembled on Polycomb response elements (PREs) to maintain tissue and stage-specific patterns of gene expression. Critical to coordinating gene expression with the process of differentiation, the activity of PREs can be switched “on” and “off.” When on, the PRE imposes a silenced state on the genes in the same domain that is stably inherited through multiple rounds of cell division. When the PRE is switched off, the domain is in a state permissive for gene expression that can be stably inherited. Previous studies have suggested that a burst of transcription through a PRE sequence displaces PcG proteins and provides a universal mechanism for inducing a heritable switch in PRE activity from on to off; however, the evidence favoring this model is indirect. Here, we have directly tested the transcriptional read-through mechanism. Contrary to previous suggestions, we show that transcription through the PRE is not sufficient for inducing an epigenetic switch in PRE activity. In fact, even high levels of continuous transcription through a PRE fails to dislodge the PcG proteins, nor does it remove repressive histone marks. Our results indicate that other mechanisms involving adjacent DNA regulatory elements must be implicated in heritable switch of PRE activity. PMID:26504232

  2. Improving the Thermostability and Activity of a Thermophilic Subtilase by Incorporating Structural Elements of Its Psychrophilic Counterpart

    PubMed Central

    Xu, Bi-Lin; Dai, Meihong; Chen, Yuanhao; Meng, Dongheng; Wang, Yasi; Fang, Nan; Tang, Xiao-Feng

    2015-01-01

    The incorporation of the structural elements of thermostable enzymes into their less stable counterparts is generally used to improve enzyme thermostability. However, the process of engineering enzymes with both high thermostability and high activity remains an important challenge. Here, we report that the thermostability and activity of a thermophilic subtilase were simultaneously improved by incorporating structural elements of a psychrophilic subtilase. There were 64 variable regions/residues (VRs) in the alignment of the thermophilic WF146 protease, mesophilic sphericase, and psychrophilic S41. The WF146 protease was subjected to systematic mutagenesis, in which each of its VRs was replaced with those from S41 and sphericase. After successive rounds of combination and screening, we constructed the variant PBL5X with eight amino acid residues from S41. The half-life of PBL5X at 85°C (57.1 min) was approximately 9-fold longer than that of the wild-type (WT) WF146 protease (6.3 min). The substitutions also led to an increase in the apparent thermal denaturation midpoint temperature (Tm) of the enzyme by 5.5°C, as determined by differential scanning calorimetry. Compared to the WT, PBL5X exhibited high caseinolytic activity (25 to 95°C) and high values of Km and kcat (25 to 80°C). Our study may provide a rational basis for developing highly stable and active enzymes, which are highly desired in industrial applications. PMID:26150464

  3. Piperine Induces Hepatic Low-Density Lipoprotein Receptor Expression through Proteolytic Activation of Sterol Regulatory Element-Binding Proteins

    PubMed Central

    Ochiai, Ayasa; Miyata, Shingo; Shimizu, Makoto; Inoue, Jun; Sato, Ryuichiro

    2015-01-01

    Elevated plasma low-density lipoprotein (LDL) cholesterol is considered as a risk factor for atherosclerosis. Because the hepatic LDL receptor (LDLR) uptakes plasma lipoproteins and lowers plasma LDL cholesterol, the activation of LDLR is a promising drug target for atherosclerosis. In the present study, we identified the naturally occurring alkaloid piperine, as an inducer of LDLR gene expression by screening the effectors of human LDLR promoter. The treatment of HepG2 cells with piperine increased LDLR expression at mRNA and protein levels and stimulated LDL uptake. Subsequent luciferase reporter gene assays revealed that the mutation of sterol regulatory element-binding protein (SREBP)-binding element abolished the piperine-mediated induction of LDLR promoter activity. Further, piperine treatments increased mRNA levels of several SREBP targets and mature forms of SREBPs. However, the piperine-mediated induction of the mature forms of SREBPs was not observed in SRD–15 cells, which lack insulin-induced gene–1 (Insig–1) and Insig–2. Finally, the knockdown of SREBPs completely abolished the piperine-meditated induction of LDLR gene expression in HepG2 cells, indicating that piperine stimulates the proteolytic activation of SREBP and subsequent induction of LDLR expression and activity. PMID:26431033

  4. Active moss biomonitoring of small-scale spatial distribution of airborne major and trace elements in the Belgrade urban area.

    PubMed

    Vuković, Gordana; Aničić Urošević, Mira; Razumenić, Ivana; Goryainova, Zoya; Frontasyeva, Marina; Tomašević, Milica; Popović, Aleksandar

    2013-08-01

    In urban environments, human exposure to air pollutants is expected to be significantly increased, especially near busy traffic streets, street canyons, tunnels, etc. where urban topography and microclimate may additionally cause poor air conditions giving rise to pollution hotspots. As a practical and cost-effective approach, active moss biomonitoring survey of some major and trace element air pollution was performed in the Belgrade street canyons and city tunnel in 2011 with the aim to evaluate possibility of using Sphagnum girgensohnii moss bags for investigation of the small-scale vertical and horizontal distribution patterns of the elements. In five street canyons, the moss bags were hung at heights of about 4, 8 and 16 m, during 10 weeks, and also, for the same time, the moss bags were exposed in the tunnel, in front of and out of it. After the exposure period, the concentrations of Al, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Sr, V and Zn in the moss were determined by inductively coupled plasma optical emission spectrometry. According to the results, in all street canyons, the vertical distribution patterns of the moss elements concentration (Al, Ba, Co, Cr, Cu, Ni, Pb, Sr, V and Zn) showed statistically significant decrease from the first to the third heights of bags exposure. In the tunnel experiment, from inner to out of the tunnel, for Al, Ba, Cd, Co, Cr, Cu, Fe, K and Zn, decreasing trend of concentrations was obtained. Significantly higher concentration of the elements was pronounced for the tunnel in comparison with the street canyons. The results indicate that the use of S. girgensohnii moss bags is a simple, sensitive and inexpensive way to monitor the small-scale inner city spatial distribution of airborne major and trace element content. PMID:23430735

  5. Experimental parameters optimization of instrumental neutron activation analysis in order to determine selected elements in some industrial soils in Turkey

    NASA Astrophysics Data System (ADS)

    Haciyakupoglu, Sevilay; Nur Esen, Ayse; Erenturk, Sema

    2014-08-01

    The purpose of this study is optimization of the experimental parameters for analysis of soil matrix by instrumental neutron activation analysis and quantitative determination of barium, cerium, lanthanum, rubidium, scandium and thorium in soil samples collected from industrialized urban areas near Istanbul. Samples were irradiated in TRIGA MARK II Research Reactor of Istanbul Technical University. Two types of reference materials were used to check the accuracy of the applied method. The achieved results were found to be in compliance with certified values of the reference materials. The calculated En numbers for mentioned elements were found to be less than 1. The presented data of element concentrations in soil samples will help to trace the pollution as an impact of urbanization and industrialization, as well as providing database for future studies.

  6. Sequence elements in the human osteocalcin gene confer basal activation and inducible response to hormonal vitamin D sub 3

    SciTech Connect

    Kerner, S.A.; Scott, R.A.; Pike, J.W. )

    1989-06-01

    Osteoblast-specific expression of the bone protein osteocalcin is controlled at the transcriptional level by the steroid hormone 1{alpha},25-dihydroxyvitamin D{sub 3}. As this protein may represent a marker for bone activity in human disease, the authors examined the regulation of its expression at the molecular level by evaluating human osteocalcin gene promoter function. They describe regions within the promoter that contribute to basal expression of the gene in osteoblast-like cells in culture. Further, they define a 21-base-pair DNA element with the sequence 5{prime}-GTGACTCACCGGGTGAACGGG-3{prime}, which acts in cis to mediate 1{alpha},25-dihydroxyvitamin D{sub 3} inducibility of the osteocalcin gene. This response element bears sequence similarity with other short DNA segments, particularly those for estrogen and thyroid hormone, which act together with their respective trans-acting receptors to modulate gene transcription.

  7. Functional characterization of neural-restrictive silencer element in mouse pituitary adenylate cyclase-activating polypeptide (PACAP) gene expression.

    PubMed

    Sugawara, Hideki; Tominaga, Aiko; Inoue, Kazuhiko; Takeda, Yasuo; Yamada, Katsushi; Miyata, Atsuro

    2014-11-01

    Pituitary adenylate cyclase-activating polypeptide (PACAP) is predominantly localized in the nervous system, but the underlying mechanism in its neuron-specific expression remains unclear. In addition to two neural-restrictive silencer-like element (NRSLE1 and 2), as reported previously, we have identified the third element in -1,601 to -1,581 bp from the translational initiation site of mouse PACAP gene and termed it as NRSLE3, of which, the sequence and location were highly conserved among mouse, rat, and human PACAP genes. In luciferase reporter assay, the deletion or site-directed mutagenesis of NRSLE3 in the reporter gene construct, driven by heterologous SV40 promoter, cancelled the repression of luciferase activity in non-neuronal Swiss-3T3 cells. Furthermore, its promoter activity was significantly repressed in Swiss-3T3 cells, but not in neuronal-differentiated PC12 cells. The electrophoretic mobility shift assay (EMSA) with nuclear extracts of Swiss-3T3 cells demonstrated a specific complex with NRSLE3 probe that exhibited the same migration with the neural-restrictive silencer element (NRSE) probe of rat type II sodium channel gene. During neuronal differentiation of PC12 cells, the increment of PACAP mRNA exhibited the correlation with that of REST4 mRNA, which is a neuron-specific variant form of neural-restrictive silencer factor (NRSF). In undifferentiated PC12 cells, trichostatin A (TSA), a histone deacetylase (HDAC) inhibitor, which indirectly inhibits NRSF-mediated gene silencing, increased PACAP mRNA level and attenuated the repression of promoter activity of 5' flanking region of mouse PACAP gene containing NRSLEs. These suggest that the NRSE-NRSF system implicates in the regulatory mechanism of neuron-specific expression of PACAP gene. PMID:24939248

  8. Finite element analyses of thin film active grazing incidence x-ray optics

    NASA Astrophysics Data System (ADS)

    Davis, William N.; Reid, Paul B.; Schwartz, Daniel A.

    2010-09-01

    The Chandra X-ray Observatory, with its sub-arc second resolution, has revolutionized X-ray astronomy by revealing an extremely complex X-ray sky and demonstrating the power of the X-ray window in exploring fundamental astrophysical problems. Larger area telescopes of still higher angular resolution promise further advances. We are engaged in the development of a mission concept, Generation-X, a 0.1 arc second resolution x-ray telescope with tens of square meters of collecting area, 500 times that of Chandra. To achieve these two requirements of imaging and area, we are developing a grazing incidence telescope comprised of many mirror segments. Each segment is an adjustable mirror that is a section of a paraboloid or hyperboloid, aligned and figure corrected in situ on-orbit. To that end, finite element analyses of thin glass mirrors are performed to determine influence functions for each actuator on the mirrors, in order to develop algorithms for correction of mirror deformations. The effects of several mirror mounting schemes are also studied. The finite element analysis results, combined with measurements made on prototype mirrors, will be used to further refine the correction algorithms.

  9. Production and evolution of light elements in active star-forming regions.

    PubMed

    Cassé, M; Lehoucq, R; Vangioni-Flam, E

    1995-01-26

    Collisions between cosmic rays (energetic protons and alpha-particles) and carbon, nitrogen and oxygen in the interstellar medium have been considered to be the main source of lithium, beryllium and boron, through fragmentation of the larger nuclei. But this mechanism is unable to account for the observed Solar System abundances of the isotopes 7Li and 11B. The recent detection of an excess of gamma-rays in the direction of the star-forming region in the Orion cloud has been interpreted as arising from the excitation of carbon and oxygen nuclei ejected from supernovae when they collide with the surrounding gas, which is primarily molecular and atomic hydrogen. Here we investigate the consequences of the two-body interactions of the ejected carbon and oxygen nuclei (and the alpha-particles ejected with them) with the hydrogen and helium in the surrounding gas, using a model developed previously. We show that these interactions offer a way to make lithium, beryllium and boron that is independent of the abundance of heavy elements in the surrounding medium. Such supernova-driven interactions, combined with the effect of galactic cosmic rays, can explain the observed Solar System abundances of these light elements. PMID:7830765

  10. Transmission-blocking activity induced by malaria vaccine candidates Pfs25/Pvs25 is a direct and predictable function of antibody titer

    PubMed Central

    Miura, Kazutoyo; Keister, David B; Muratova, Olga V; Sattabongkot, Jetsumon; Long, Carole A; Saul, Allan

    2007-01-01

    Background Mosquito stage malaria vaccines are designed to induce an immune response in the human host that will block the parasite's growth in the mosquito and consequently block transmission of the parasite. A mosquito membrane-feeding assay (MFA) is used to test transmission-blocking activity (TBA), but in this technique cannot accommodate many samples. A clear understanding of the relationship between antibody levels and TBA may allow ELISA determinations to be used to predict TBA and assist in planning vaccine development. Methods Rabbit anti-Pfs25 sera and monkey anti-Pvs25 sera were generated and the antibody titers were determined by a standardized ELISA. The biological activity of the same sera was tested by MFA using Plasmodium gametocytes (cultured Plasmodium falciparum or Plasmodium vivax from malaria patients) and Anopheles mosquitoes. Results Anti-Pfs25 and anti-Pvs25 sera showed that ELISA antibody units correlate with the percent reduction in the oocyst density per mosquito (Spearman Rank correlations: 0.934 and 0.616, respectively), and fit a hyperbolic curve when percent reduction in oocyst density is plotted against antibody units of the tested sample. Antibody levels also correlated with the number of mosquitoes that failed to become infected, and this proportion can be calculated from the reduction in oocyst numbers and the distribution of oocysts per infected mosquito in control group. Conclusion ELISA data may be used as a surrogate for the MFA to evaluate transmission-blocking vaccine efficacy. This will facilitate the evaluation of transmission-blocking vaccines and implementation of this malaria control strategy. PMID:17686163

  11. Transmissible amyloid.

    PubMed

    Tjernberg, L O; Rising, A; Johansson, J; Jaudzems, K; Westermark, P

    2016-08-01

    There are around 30 human diseases associated with protein misfolding and amyloid formation, each one caused by a certain protein or peptide. Many of these diseases are lethal and together they pose an enormous burden to society. The prion protein has attracted particular interest as being shown to be the pathogenic agent in transmissible diseases such as kuru, Creutzfeldt-Jakob disease and bovine spongiform encephalopathy. Whether similar transmission could occur also in other amyloidoses such as Alzheimer's disease, Parkinson's disease and serum amyloid A amyloidosis is a matter of intense research and debate. Furthermore, it has been suggested that novel biomaterials such as artificial spider silk are potentially amyloidogenic. Here, we provide a brief introduction to amyloid, prions and other proteins involved in amyloid disease and review recent evidence for their potential transmission. We discuss the similarities and differences between amyloid and silk, as well as the potential hazards associated with protein-based biomaterials. PMID:27002185

  12. The upstream activator CTF/NF1 and RNA polymerase II share a common element involved in transcriptional activation.

    PubMed Central

    Xiao, H; Lis, J T; Xiao, H; Greenblatt, J; Friesen, J D

    1994-01-01

    The carboxy-terminal domain (CTD) of the largest subunit of RNA polymerase II consists of tandem repeats of a heptapeptide with the consensus YSPTSPS. It has been shown that the heptapeptide repeat interacts directly with the general transcription factor TFIID. We report here that the CTD activates transcription when fused to the DNA-binding domain of GAL4. More importantly, we find that the proline-rich transcriptional activation domain of the CCAAT-box-binding factor CTF/NF1 contains a sequence with striking similarity to the heptapeptide repeats of the CTD. We show that this CTD-like motif is essential for the transcriptional activator function of the proline-rich domain of CTF/NF1. Deletion of and point mutations in this CTD-like motif abolish the transcriptional activator function of the proline-rich domain, while natural CTD repeats from RNA polymerase II are fully functional in place of the CTD-like motif. We further show that the proline-rich activation domain of CTF/NF1 interacts directly with the TATA-box-binding protein (TBP), and that a mutation in the CTD-like motif that abolishes transcriptional activation reduces the affinity of the proline-rich domain for TBP. These results demonstrate that a class of proline-rich activator proteins and RNA polymerase II possess a common structural and functional component which can interact with the same target in the general transcription machinery. We discuss the implications of these results for the mechanisms of transcriptional activation in eucaryotes. Images PMID:8029001

  13. The role of an inverted CCAAT element in transcriptional activation of the human DNA topoisomerase IIalpha gene by heat shock.

    PubMed

    Furukawa, M; Uchiumi, T; Nomoto, M; Takano, H; Morimoto, R I; Naito, S; Kuwano, M; Kohno, K

    1998-04-24

    Expression of the DNA topoisomerase IIalpha (topoIIalpha) gene is highly sensitive to various environmental stimuli including heat shock. The amount of topoIIalpha mRNA was increased 1.5-3-fold 6-24 h after exposure of T24 human urinary bladder cancer cells to heat shock stress at 43 degreesC for 1 h. The effect of heat shock on the transcriptional activity of the human topoIIalpha gene promoter was investigated by transient transfection of T24 cells with luciferase reporter plasmids containing various lengths of the promoter sequence. The transcriptional activity of the full-length promoter (nucleotides (nt) -295 to +85) and of three deletion constructs (nt -197 to +85, -154 to +85, and -74 to +85) was increased approximately 3-fold 24 h after heat shock stress. In contrast, the transcriptional activity of the minimal promoter (nt -20 to +85), which lacks the first inverted CCAAT element (ICE1), the GC box, and the heat shock element located between nt -74 and -21, was not increased by heat shock. Furthermore, the transcriptional activity of promoter constructs containing mutations in the GC box or heat shock element, but not that of a construct containing mutations in ICE1, was significantly increased by heat shock. Electrophoretic mobility shift assays revealed reduced binding of a nuclear factor to an oligonucleotide containing ICE1 when nuclear extracts were derived from cells cultured for 3-24 h after heat shock. No such change in factor binding was apparent with an oligonucleotide containing the heat shock element of the topoIIalpha gene promoter. Finally, in vivo footprint analysis of the topoIIalpha gene promoter revealed that two G residues of ICE1 that were protected in control cells became sensitive to dimethyl sulfate modification after heat shock. These results suggest that transcriptional activation of the topoIIalpha gene by heat shock requires the release of a negative regulatory factor from ICE1. PMID:9553115

  14. RF tuning element

    NASA Technical Reports Server (NTRS)

    McGrath, William R. (Inventor); Lubecke, Victor M. (Inventor)

    1992-01-01

    A device for tuning a circuit includes a substrate, a transmission line on the substrate that includes first and second conductors coupled to a circuit to be tuned, and a movable short-circuit for varying the impedance the transmission line presents to the circuit to be tuned. The movable short-circuit includes a dielectric layer disposed atop the transmission line and a distributed shorting element in the form of a conductive member that is configured to be slid along at least a portion of the transmission line atop the dielectric layer. The conductive member is configured to span the first and second conductors of the transmission line and to define at least a first opening that spans the two conductors so that the conductive member includes first and second sections separated by the first opening. The first and second sections of the conductive member combine with the first and second conductors of the transmission line to form first and second low impedance sections of transmission line, and the opening combines with the first and second conductors of the transmission line and the dielectric layer to form a first high impedance section of transmission line intermediate the first and second low impedance sections. Each of the first low impedance section and the first high impedance section have a length along the transmission line of approximately one-quarter wavelength, thus providing a periodic variation of transmission line impedance. That enhances reflection of rf power.

  15. West Nile Virus Activity in a Winter Roost of American Crows (Corvus brachyrhynchos): Is Bird-To-Bird Transmission Important in Persistence and Amplification?

    PubMed Central

    Hinton, M. G.; Reisen, W. K.; Wheeler, S. S.; Townsend, A. K.

    2015-01-01

    Since its emergence in North America, West Nile virus (WNV) has had a large impact on equines, humans, and wild bird communities, yet gaps remain in our understanding of how the virus persists at temperate latitudes when winter temperatures preclude virus replication and host-seeking activity by mosquito vectors. Bird-to-bird transmission at large communal American Crow roosts could provide one mechanism for WNV persistence. Herein, we describe seasonal patterns of crow and Culex mosquito abundance, WNV infection rates, and the prevalence of WNV-positive fecal samples at a winter crow roost to test the hypothesis that bird-to-bird transmission allows WNV to persist at winter crow roosts. Samples were collected from large winter crow roosts in the Sacramento Valley of California from January 2013 until August 2014, encompassing two overwintering roost periods. West Nile virus RNA was detected in local crow carcasses in both summer [13/18 (72% WNV positive)] and winter [18/44 (41% WNV positive)] 2013–2014. Winter infections were unlikely to have arisen by recent bites from infected mosquitoes because Culex host-seeking activity was very low in winter and all Culex mosquitoes collected during winter months tested negative for WNV. Opportunities existed for fecal-oral transfer at the overwintering roost: most carcasses that tested positive for WNV had detectable viral RNA in both kidney and cloacal swabs, suggesting that infected crows were shedding virus in their feces, and >50% of crows at the roost were stained with feces by mid-winter. Moreover, 2.3% of fecal samples collected in late summer, when mosquitoes were active, tested positive for WNV RNA. Nevertheless, none of the 1,119 feces collected from three roosts over two winters contained detectable WNV RNA. This study provided evidence of WNV infection in overwintering American crows without mosquito vector activity, but did not elucidate a mechanism of WNV transmission during winter. PMID:26335475

  16. Mice lacking brain/kidney phosphate-activated glutaminase (GLS1) have impaired glutamatergic synaptic transmission, altered breathing, disorganized goal-directed behavior and die shortly after birth

    PubMed Central

    Masson, Justine; Darmon, Michèle; Conjard, Agnès; Chuhma, Nao; Ropert, Nicole; Thoby-Brisson, Muriel; Foutz, Arthur S.; Parrot, Sandrine; Miller, Gretchen M.; Jorisch, Renée; Polan, Jonathan; Hamon, Michel; Hen, René; Rayport, Stephen

    2009-01-01

    Neurotransmitter glutamate has been thought to derive mainly from glutamine via the action of glutaminase type 1 (GLS1). To address the importance of this pathway in glutamatergic transmission, we knocked out GLS1 in mice. The insertion of a STOP cassette by homologous recombination produced a null allele that blocked transcription, encoded no immunoreactive protein and abolished GLS1 enzymatic activity. Null mutants were slightly smaller, were deficient in goal-directed behavior, hypoventilated and died in the first post-natal day. No gross or microscopic defects were detected in peripheral organs or in the central nervous system. In cultured neurons from the null mutants, miniature EPSC amplitude and duration were normal; however, the amplitude of evoked EPSCs decayed more rapidly with sustained 10 Hz stimulation, consistent with an observed reduction in depolarization-evoked glutamate release. Because of this activity-dependent impairment in glutamatergic transmission, we surmised that respiratory networks, which require temporal summation of synaptic input, would be particularly affected. We found that the amplitude of inspirations was decreased in vivo, chemosensitivity to CO2 was severely altered, and the frequency of pacemaker activity recorded in the respiratory generator in the Pre-Bötzinger complex, a glutamatergic brainstem network that can be isolated in vitro, was increased. Our results show that while alternate pathways to GLS1 glutamate synthesis support baseline glutamatergic transmission, the GLS1 pathway is essential for maintaining the function of active synapses, and so the mutation is associated with impaired respiratory function, abnormal goal-directed behavior and neonatal demise. PMID:16641247

  17. Multiple cis Regulatory Elements Control RANTES Promoter Activity in Alveolar Epithelial Cells Infected with Respiratory Syncytial Virus

    PubMed Central

    Casola, Antonella; Garofalo, Roberto P.; Haeberle, Helene; Elliott, Todd F.; Lin, Rongtuan; Jamaluddin, Mohammad; Brasier, Allan R.

    2001-01-01

    Respiratory syncytial virus (RSV) produces intense pulmonary inflammation, in part through its ability to induce chemokine synthesis in infected airway epithelial cells. RANTES (regulated upon activation, normally T-cell expressed and presumably secreted) is a CC chemokine which recruits and activates monocytes, lymphocytes, and eosinophils, all cell types present in the lung inflammatory infiltrate induced by RSV infection. In this study, we analyzed the mechanism of RSV-induced RANTES promoter activation in human type II alveolar epithelial cells (A549 cells). Promoter deletion and mutagenesis experiments indicate that RSV requires the presence of five different cis regulatory elements, located in the promoter fragment spanning from −220 to +55 nucleotides, corresponding to NF-κB, C/EBP, Jun/CREB/ATF, and interferon regulatory factor (IRF) binding sites. Although site mutations of the NF-κB, C/EBP, and CREB/AP-1 like sites reduce RSV-induced RANTES gene transcription to 50% or less, only mutations affecting IRF binding completely abolish RANTES inducibility. Supershift and microaffinity isolation assays were used to identify the different transcription factor family members whose DNA binding activity was RSV inducible. Expression of dominant negative mutants of these transcription factors further established their central role in virus-induced RANTES promoter activation. Our finding that the presence of multiple cis regulatory elements is required for full activation of the RANTES promoter in RSV-infected alveolar epithelial cells supports the enhanceosome model for RANTES gene transcription, which is absolutely dependent on binding of IRF transcription factors. The identification of regulatory mechanisms of RANTES gene expression is fundamental for rational design of inhibitors of RSV-induced lung inflammation. PMID:11413310

  18. Prompt Gamma-Ray Neutron Activation Analysis (PGNAA) for Elemental Analysis

    SciTech Connect

    Robin P. Gardner

    2006-04-11

    This research project was to improve the prompt gamma-ray neutron activation analysis (PGNAA) measurement approach for bulk analysis, oil well logging, and small sample thermal enutron bean applications.

  19. Active tectonics in Taiwan: insights from a 3-D viscous finite element model

    NASA Astrophysics Data System (ADS)

    Sun, Yujun; Liu, Mian; Dong, Shuwen; Zhang, Huai; Shi, Yaolin

    2015-12-01

    Taiwan is a young orogenic belt with complex spatial distributions of deformation and earthquakes. We have constructed a three-dimensional finite element model to explore how the interplays between lithospheric structure and plate boundary processes control the distribution of stress and strain rates in the Taiwan region. The model assumes a liberalized power-law rheology and incorporates main lithospheric structures; the model domain is loaded by the present-day crustal velocity applied at its boundaries. The model successfully reproduces the main features of the GPS-measured strain rate patterns and the earthquake-indicated stress states in the Taiwan region. The best fitting model requires the viscosity of the lower crust to be two orders of magnitude lower than that of the upper crust and lithospheric mantle. The calculated deviatoric stress is high in regions of thrust faulting and low in regions of extensional and strike-slip faulting, consistent with the spatial pattern of seismic intensity in Taiwan.

  20. Transposable Element Proliferation and Genome Expansion Are Rare in Contemporary Sunflower Hybrid Populations Despite Widespread Transcriptional Activity of LTR Retrotransposons

    PubMed Central

    Kawakami, Takeshi; Dhakal, Preeti; Katterhenry, Angela N.; Heatherington, Chelsea A.; Ungerer, Mark C.

    2011-01-01

    Hybridization is a natural phenomenon that has been linked in several organismal groups to transposable element derepression and copy number amplification. A noteworthy example involves three diploid annual sunflower species from North America that have arisen via ancient hybridization between the same two parental taxa, Helianthus annuus and H. petiolaris. The genomes of the hybrid species have undergone large-scale increases in genome size attributable to long terminal repeat (LTR) retrotransposon proliferation. The parental species that gave rise to the hybrid taxa are widely distributed, often sympatric, and contemporary hybridization between them is common. Natural H. annuus × H. petiolaris hybrid populations likely served as source populations from which the hybrid species arose and, as such, represent excellent natural experiments for examining the potential role of hybridization in transposable element derepression and proliferation in this group. In the current report, we examine multiple H. annuus × H. petiolaris hybrid populations for evidence of genome expansion, LTR retrotransposon copy number increases, and LTR retrotransposon transcriptional activity. We demonstrate that genome expansion and LTR retrotransposon proliferation are rare in contemporary hybrid populations, despite independent proliferation events that took place in the genomes of the ancient hybrid species. Interestingly, LTR retrotransposon lineages that proliferated in the hybrid species genomes remain transcriptionally active in hybrid and nonhybrid genotypes across the entire sampling area. The finding of transcriptional activity but not copy number increases in hybrid genotypes suggests that proliferation and genome expansion in contemporary hybrid populations may be mitigated by posttranscriptional mechanisms of repression. PMID:21282712

  1. Survey sequencing reveals elevated DNA transposon activity, novel elements, and variation in repetitive landscapes among vesper bats.

    PubMed

    Pagán, Heidi J T; Macas, Jiří; Novák, Petr; McCulloch, Eve S; Stevens, Richard D; Ray, David A

    2012-01-01

    The repetitive landscapes of mammalian genomes typically display high Class I (retrotransposon) transposable element (TE) content, which usually comprises around half of the genome. In contrast, the Class II (DNA transposon) contribution is typically small (<3% in model mammals). Most mammalian genomes exhibit a precipitous decline in Class II activity beginning roughly 40 Ma. The first signs of more recently active mammalian Class II TEs were obtained from the little brown bat, Myotis lucifugus, and are reflected by higher genome content (~5%). To aid in determining taxonomic limits and potential impacts of this elevated Class II activity, we performed 454 survey sequencing of a second Myotis species as well as four additional taxa within the family Vespertilionidae and an outgroup species from Phyllostomidae. Graph-based clustering methods were used to reconstruct the major repeat families present in each species and novel elements were identified in several taxa. Retrotransposons remained the dominant group with regard to overall genome mass. Elevated Class II TE composition (3-4%) was observed in all five vesper bats, while less than 0.5% of the phyllostomid reads were identified as Class II derived. Differences in satellite DNA and Class I TE content are also described among vespertilionid taxa. These analyses present the first cohesive description of TE evolution across closely related mammalian species, revealing genome-scale differences in TE content within a single family. PMID:22491057

  2. Evidence of active role played by the nonmagnetic element Sr in magnetostructural coupling in SrRuO[subscript 3

    SciTech Connect

    Lahiri, Debdutta; Shibata, T.; Chattopadhyay, S.; Kanungo, Sudipta; Saha-Dasgupta, T.; Singh, R.S.; Sharma, Surinder M.; Maiti, Kalobaran

    2010-11-12

    We study the magnetic transition in SrRuO{sub 3}, the only itinerant 4d ferromagnet, employing x-ray absorption fine structure study and state-of-the-art band-structure calculations. Both experimental and theoretical results reveal an unusual evolution of the local structural parameters around the spectator element, Sr, across the magnetic transition. Interestingly, such evolution of the Sr-related bonds nucleate at a temperature, T*, higher than the magnetic transition temperature, indicating the presence of a precursor effect. Contrary to common belief, these results point to the active role played by the Sr ion in the magnetostructural coupling present in this compound.

  3. Determination of 30 elements in coal and fly ash by thermal and epithermal neutron-activation analysis

    USGS Publications Warehouse

    Rowe, J.J.; Steinnes, E.

    1977-01-01

    Thirty elements are determined in coal and fly ash by instrumental neutron-activation analysis using both thermal and epithermal irradiation. Gamma-ray spectra were recorded 7 and 20 days after the irradiations. The procedure is applicable to the routine analysis of coals and fly ash. Epithermal irradiation was found preferable for the determination of Ni, Zn, As, Se, Br, Rb, Sr, Mo, Sb, Cs, Ba, Sm, Tb, Hf, Ta, W, Th and U, whereas thermal irradiation was best for Sc, Cr, Fe, Co, La, Ce, Nd, Eu, Yb and Lu. Results for SRM 1632 (coal) and SRM 1633 (fly ash) agree with those of other investigators. ?? 1977.

  4. Structural investigation of heteroyohimbine alkaloid synthesis reveals active site elements that control stereoselectivity.

    PubMed

    Stavrinides, Anna; Tatsis, Evangelos C; Caputi, Lorenzo; Foureau, Emilien; Stevenson, Clare E M; Lawson, David M; Courdavault, Vincent; O'Connor, Sarah E

    2016-01-01

    Plants produce an enormous array of biologically active metabolites, often with stereochemical variations on the same molecular scaffold. These changes in stereochemistry dramatically impact biological activity. Notably, the stereoisomers of the heteroyohimbine alkaloids show diverse pharmacological activities. We reported a medium chain dehydrogenase/reductase (MDR) from Catharanthus roseus that catalyses formation of a heteroyohimbine isomer. Here we report the discovery of additional heteroyohimbine synthases (HYSs), one of which produces a mixture of diastereomers. The crystal structures for three HYSs have been solved, providing insight into the mechanism of reactivity and stereoselectivity, with mutation of one loop transforming product specificity. Localization and gene silencing experiments provide a basis for understanding the function of these enzymes in vivo. This work sets the stage to explore how MDRs evolved to generate structural and biological diversity in specialized plant metabolism and opens the possibility for metabolic engineering of new compounds based on this scaffold. PMID:27418042

  5. Structural investigation of heteroyohimbine alkaloid synthesis reveals active site elements that control stereoselectivity

    PubMed Central

    Stavrinides, Anna; Tatsis, Evangelos C.; Caputi, Lorenzo; Foureau, Emilien; Stevenson, Clare E. M.; Lawson, David M.; Courdavault, Vincent; O'Connor, Sarah E.

    2016-01-01

    Plants produce an enormous array of biologically active metabolites, often with stereochemical variations on the same molecular scaffold. These changes in stereochemistry dramatically impact biological activity. Notably, the stereoisomers of the heteroyohimbine alkaloids show diverse pharmacological activities. We reported a medium chain dehydrogenase/reductase (MDR) from Catharanthus roseus that catalyses formation of a heteroyohimbine isomer. Here we report the discovery of additional heteroyohimbine synthases (HYSs), one of which produces a mixture of diastereomers. The crystal structures for three HYSs have been solved, providing insight into the mechanism of reactivity and stereoselectivity, with mutation of one loop transforming product specificity. Localization and gene silencing experiments provide a basis for understanding the function of these enzymes in vivo. This work sets the stage to explore how MDRs evolved to generate structural and biological diversity in specialized plant metabolism and opens the possibility for metabolic engineering of new compounds based on this scaffold. PMID:27418042

  6. The developmental activation of the chicken lysozyme locus in transgenic mice requires the interaction of a subset of enhancer elements with the promoter.

    PubMed Central

    Huber, M C; Jägle, U; Krüger, G; Bonifer, C

    1997-01-01

    The complete chicken lysozyme locus is expressed in a position independent fashion in macrophages of transgenic mice and forms the identical chromatin structure as observed with the endogenous gene in chicken cells. Individual lysozyme cis -regulatory elements reorganize their chromatin structure at different developmental stages. Accordingly, their activities are developmentally regulated, indicating a differential role of these elements in locus activation. We have shown previously that a subset of enhancer elements and the promoter are sufficient to activate transcription of the chicken lysozyme gene at the correct developmental stage. Here, we analyzed to which grade the developmentally controlled chromatin reorganizing capacity of cis -regulatory elements in the 5'-region of the chicken lysozyme locus is dependent on promoter elements, and we examined whether the lysozyme locus carries a dominant chromatin reorganizing element. To this end we generated transgenic mouse lines carrying constructs with a deletion of the lysozyme promoter. Expression of the transgene in macrophages is abolished, however, the chromatin reorganizing ability of the cis -regulatory elements is differentially impaired. Some cis -elements require the interaction with the promoter to stabilize transcription factor complexes detectable as DNase I hypersensitive sites in chromatin, whereas other elements reorganize their chromatin structure autonomously. PMID:9224598

  7. Classifying organic materials by oxygen-to-carbon elemental ratio to predict the activation regime of Cloud Condensation Nuclei (CCN)

    NASA Astrophysics Data System (ADS)

    Kuwata, M.; Shao, W.; Lebouteiller, R.; Martin, S. T.

    2013-05-01

    The governing highly soluble, slightly soluble, or insoluble activation regime of organic compounds as cloud condensation nuclei (CCN) was examined as a function of oxygen-to-carbon elemental ratio (O : C). New data were collected for adipic, pimelic, suberic, azelaic, and pinonic acids. Secondary organic materials (SOMs) produced by α-pinene ozonolysis and isoprene photo-oxidation were also included in the analysis. The saturation concentrations C of the organic compounds in aqueous solutions served as the key parameter for delineating regimes of CCN activation, and the values of C were tightly correlated to the O : C ratios. The highly soluble, slightly soluble, and insoluble regimes of CCN activation were found to correspond to ranges of [O : C] > 0.6, 0.2 < [O : C] < 0.6, and [O : C] < 0.2, respectively. These classifications were evaluated against CCN activation data of isoprene-derived SOM (O : C = 0.69-0.72) and α-pinene-derived SOM (O : C = 0.38-0.48). Isoprene-derived SOM had highly soluble activation behavior, consistent with its high O : C ratio. For α-pinene-derived SOM, although CCN activation can be modeled as a highly soluble mechanism, this behavior was not predicted by the O : C ratio, for which a slightly soluble mechanism was anticipated. Complexity in chemical composition, resulting in continuous water uptake and the absence of a deliquescence transition that can thermodynamically limit CCN activation, might explain the difference in the behavior of α-pinene-derived SOM compared to that of pure organic compounds. The present results suggest that atmospheric particles dominated by hydrocarbon-like organic components do not activate (i.e., insoluble regime) whereas those dominated by oxygenated organic components activate (i.e., highly soluble regime) for typical atmospheric cloud life cycles.

  8. Classifying organic materials by oxygen-to-carbon elemental ratio to predict the activation regime of cloud condensation nuclei (CCN)

    NASA Astrophysics Data System (ADS)

    Kuwata, M.; Shao, W.; Lebouteiller, R.; Martin, S. T.

    2012-12-01

    The governing highly soluble, slightly soluble, or insoluble activation regime of organic compounds as cloud condensation nuclei (CCN) was examined as a function of oxygen-to-carbon elemental ratio (O : C). New data were collected for adipic, pimelic, suberic, azelaic and pinonic acids. Secondary organic materials (SOMs) produced by α-pinene ozonolysis and isoprene photo-oxidation were also included in the analysis. The saturation concentrations C of the organic compounds in aqueous solutions served as the key parameter for delineating regimes of CCN activation, and the values of C were tightly correlated to the O : C ratios. The highly soluble, slightly soluble, and insoluble regimes of CCN activation were found to correspond to ranges of [O : C] > 0.6, 0.2 < [O : C] < 0.6, and [O : C] < 0.2, respectively. These classifications were evaluated against CCN activation data of isoprene-derived SOM (O : C = 0.69-0.72) and α-pinene-derived SOM (O : C = 0.38-0.48). Isoprene-derived SOM had highly soluble activation behavior, consistent with its high O : C ratio. For α-pinene-derived SOM, although CCN activation can be modeled as a highly soluble mechanism, this behavior was not predicted by the O : C ratio, for which a slightly soluble mechanism was anticipated. Complexity in chemical composition, resulting in continuous water uptake and the absence of a deliquescence transition that can thermodynamically limit CCN activation, might explain the differences of α-pinene-derived SOM compared to the behavior of pure organic compounds. The present results suggest that atmospheric particles dominated by hydrocarbon-like organic components do not activate (i.e. insoluble regime) whereas those dominated by oxygenated organic components activate (i.e. highly soluble regime).

  9. Elements of Design-Based Science Activities That Affect Students' Motivation

    ERIC Educational Resources Information Center

    Jones, Brett D.; Chittum, Jessica R.; Akalin, Sehmuz; Schram, Asta B.; Fink, Jonathan; Schnittka, Christine; Evans, Michael A.; Brandt, Carol

    2015-01-01

    The primary purpose of this study was to examine the ways in which a 12-week after-school science and engineering program affected middle school students' motivation to engage in science and engineering activities. We used current motivation research and theory as a conceptual framework to assess 14 students' motivation through questionnaires,…

  10. Blending Elements of Economics and Political Science: Intergenerational Dialogue, Civic Engagement, and Related Student Scholarly Activity

    ERIC Educational Resources Information Center

    Catlett, Rob

    2010-01-01

    "I don't think I am good enough" was more than one student's response when invited to participate in civic engagement activities or to articulate their own original scholarly ideas. The insecurities underlying comments like this one are probably much more complex when put into the context of a student's academic life and its normal expectations.…

  11. Mechanistic insights into an engineered riboswitch: a switching element which confers riboswitch activity.

    PubMed

    Weigand, Julia E; Schmidtke, Sina R; Will, Tristan J; Duchardt-Ferner, Elke; Hammann, Christian; Wöhnert, Jens; Suess, Beatrix

    2011-04-01

    While many different RNA aptamers have been identified that bind to a plethora of small molecules only very few are capable of acting as engineered riboswitches. Even for aptamers binding the same ligand large differences in their regulatory potential were observed. We address here the molecular basis for these differences by using a set of unrelated neomycin-binding aptamers. UV melting analyses showed that regulating aptamers are thermally stabilized to a significantly higher degree upon ligand binding than inactive ones. Regulating aptamers show high ligand-binding affinity in the low nanomolar range which is necessary but not sufficient for regulation. NMR data showed that a destabilized, open ground state accompanied by extensive structural changes upon ligand binding is important for regulation. In contrast, inactive aptamers are already pre-formed in the absence of the ligand. By a combination of genetic, biochemical and structural analyses, we identified a switching element responsible for destabilizing the ligand free state without compromising the bound form. Our results explain for the first time the molecular mechanism of an engineered riboswitch. PMID:21149263

  12. Introduction of the mec Element (Methicillin Resistance) into Staphylococcus aureus Alters In Vitro Functional Activities of Fibrinogen and Fibronectin Adhesins

    PubMed Central

    Vaudaux, Pierre E.; Monzillo, Vincenza; Francois, Patrice; Lew, Daniel P.; Foster, Tim J.; Berger-Bächi, Brigitte

    1998-01-01

    Some methicillin-resistant strains of Staphylococcus aureus are defective in the production of major surface components such as protein A, clumping factor, or other important adhesins to extracellular matrix components which may play a role in bacterial colonization and infection. To evaluate the impact of methicillin resistance (mec) determinants on bacterial adhesion mediated by fibrinogen or fibronectin adhesins, we compared the in vitro attachment of two genetically distinct susceptible strains (NCTC8325 and Newman) to protein-coated surfaces with that of isogenic methicillin-resistant derivatives. All strains containing an intact mec element in their chromosomes were found to be defective in adhesion to fibrinogen and fibronectin immobilized on polymethylmethacrylate coverslips, regardless of the presence or absence of additional mutations in the femA, femB, or femC gene, known to decrease expression of methicillin resistance in S. aureus. Western ligand affinity blotting or immunoblotting of cell wall-associated adhesins revealed similar contents of fibrinogen- or fibronectin-binding proteins in methicillin-resistant strains compared to those of their methicillin-susceptible counterparts. In contrast to methicillin-resistant strains carrying a mec element in their genomes, methicillin-resistant strains constructed in vitro, by introducing the mecA gene on a plasmid, retained their adhesion phenotypes. In conclusion, the chromosomal insertion of the mec element into genetically defined strains of S. aureus impairs the in vitro functional activities of fibrinogen or fibronectin adhesins without altering their production. This effect is unrelated to the activity of the mecA gene. PMID:9517933

  13. The Chinese Hamster Dihydrofolate Reductase Replication Origin Beta Is Active at Multiple Ectopic Chromosomal Locations and Requires Specific DNA Sequence Elements for Activity

    PubMed Central

    Altman, Amy L.; Fanning, Ellen

    2001-01-01

    To identify cis-acting genetic elements essential for mammalian chromosomal DNA replication, a 5.8-kb fragment from the Chinese hamster dihydrofolate reductase (DHFR) locus containing the origin beta (ori-β) initiation region was stably transfected into random ectopic chromosomal locations in a hamster cell line lacking the endogenous DHFR locus. Initiation at ectopic ori-β in uncloned pools of transfected cells was measured using a competitive PCR-based nascent strand abundance assay and shown to mimic that at the endogenous ori-β region in Chinese hamster ovary K1 cells. Initiation activity of three ectopic ori-β deletion mutants was reduced, while the activity of another deletion mutant was enhanced. The results suggest that a 5.8-kb fragment of the DHFR ori-β region is sufficient to direct initiation and that specific DNA sequences in the ori-β region are required for efficient initiation activity. PMID:11158297

  14. A new large-DNA-fragment delivery system based on integrase activity from an integrative and conjugative element.

    PubMed

    Miyazaki, Ryo; van der Meer, Jan Roelof

    2013-07-01

    During the past few decades, numerous plasmid vectors have been developed for cloning, gene expression analysis, and genetic engineering. Cloning procedures typically rely on PCR amplification, DNA fragment restriction digestion, recovery, and ligation, but increasingly, procedures are being developed to assemble large synthetic DNAs. In this study, we developed a new gene delivery system using the integrase activity of an integrative and conjugative element (ICE). The advantage of the integrase-based delivery is that it can stably introduce a large DNA fragment (at least 75 kb) into one or more specific sites (the gene for glycine-accepting tRNA) on a target chromosome. Integrase recombination activity in Escherichia coli is kept low by using a synthetic hybrid promoter, which, however, is unleashed in the final target host, forcing the integration of the construct. Upon integration, the system is again silenced. Two variants with different genetic features were produced, one in the form of a cloning vector in E. coli and the other as a mini-transposable element by which large DNA constructs assembled in E. coli can be tagged with the integrase gene. We confirmed that the system could successfully introduce cosmid and bacterial artificial chromosome (BAC) DNAs from E. coli into the chromosome of Pseudomonas putida in a site-specific manner. The integrase delivery system works in concert with existing vector systems and could thus be a powerful tool for synthetic constructions of new metabolic pathways in a variety of host bacteria. PMID:23686268

  15. Finite Element Analysis of Active and Sensory Thermopiezoelectric Composite Materials. Degree awarded by Northwestern Univ., Dec. 2000

    NASA Technical Reports Server (NTRS)

    Lee, Ho-Jun

    2001-01-01

    Analytical formulations are developed to account for the coupled mechanical, electrical, and thermal response of piezoelectric composite materials. The coupled response is captured at the material level through the thermopiezoelectric constitutive equations and leads to the inherent capability to model both the sensory and active responses of piezoelectric materials. A layerwise laminate theory is incorporated to provide more accurate analysis of the displacements, strains, stresses, electric fields, and thermal fields through-the-thickness. Thermal effects which arise from coefficient of thermal expansion mismatch, pyroelectric effects, and temperature dependent material properties are explicitly accounted for in the formulation. Corresponding finite element formulations are developed for piezoelectric beam, plate, and shell elements to provide a more generalized capability for the analysis of arbitrary piezoelectric composite structures. The accuracy of the current formulation is verified with comparisons from published experimental data and other analytical models. Additional numerical studies are also conducted to demonstrate additional capabilities of the formulation to represent the sensory and active behaviors. A future plan of experimental studies is provided to characterize the high temperature dynamic response of piezoelectric composite materials.

  16. Activation of Sterol-response Element-binding Proteins (SREBP) in Alveolar Type II Cells Enhances Lipogenesis Causing Pulmonary Lipotoxicity*

    PubMed Central

    Plantier, Laurent; Besnard, Valérie; Xu, Yan; Ikegami, Machiko; Wert, Susan E.; Hunt, Alan N.; Postle, Anthony D.; Whitsett, Jeffrey A.

    2012-01-01

    Pulmonary inflammation is associated with altered lipid synthesis and clearance related to diabetes, obesity, and various inherited metabolic disorders. In many tissues, lipogenesis is regulated at the transcriptional level by the activity of sterol-response element-binding proteins (SREBP). The role of SREBP activation in the regulation of lipid metabolism in the lung was assessed in mice in which both Insig1 and Insig2 genes, encoding proteins that bind and inhibit SREBPs in the endoplasmic reticulum, were deleted in alveolar type 2 cells. Although deletion of either Insig1 or Insig2 did not alter SREBP activity or lipid homeostasis, deletion of both genes (Insig1/2Δ/Δ mice) activated SREBP1, causing marked accumulation of lipids that consisted primarily of cholesterol esters and triglycerides in type 2 epithelial cells and alveolar macrophages. Neutral lipids accumulated in type 2 cells in association with the increase in mRNAs regulating fatty acid, cholesterol synthesis, and inflammation. Although bronchoalveolar lavage fluid phosphatidylcholine was modestly decreased, lung phospholipid content and lung function were maintained. Insig1/2Δ/Δ mice developed lung inflammation and airspace abnormalities associated with the accumulation of lipids in alveolar type 2 cells, alveolar macrophages, and within alveolar spaces. Deletion of Insig1/2 activated SREBP-enhancing lipogenesis in respiratory epithelial cells resulting in lipotoxicity-related lung inflammation and tissue remodeling. PMID:22267724

  17. Optimal finite-element-based design of actively controlled smart composite structures under uncertainties

    NASA Astrophysics Data System (ADS)

    Orisamolu, Irewole R.; Koko, Tamunoiyala S.; Akpan, Unyime O.; Smith, Malcolm J.

    1998-07-01

    This paper presents a novel integrated formulation and robust computational tool that can be efficiently employed for the design and analysis of actively controlled smart composite structural systems. The modeling simulation capabilities account for the coupling between thermal, mechanical and electric fields within the framework of an integrated structure/control strategy. The paper also reports the formulation and implementation of an optimization capability for the design and tailoring of smart structural systems. Finally, probabilistic and fuzzy models for rationally and systematically accounting for the uncertainties in structural, control, material, and load parameters are presented. The capabilities are packaged in a comprehensive and user- friendly software system (SMARTCOM) that can be readily applied for cost-effective design or response characterization of actively controlled smart structures.

  18. Determination of trace elements in metallic materials by neutron activation analysis

    NASA Astrophysics Data System (ADS)

    Grassi, B.; La Vecchia, G. M.; Manera, S.; Salvini, A.; Zenoni, A.

    2006-05-01

    The aim of the present paper is to verify the applicability of neutron activation analysis to a metallurgic problem as a possible alternative technique to the standard investigation methodologies. A first series of measurements was performed in order to check the feasibility of irradiation and counting over metallic samples. Some of the feared problems concerned an excessive activation of the matrix and the consequent difficulties in the spectrum interpretation, as well as the removal of the radioactive waste created by the irradiation. Afterwards, a second series of measurements was performed to collect results aimed at the solution of a specific metallurgic case. The tests were performed at the TRIGA MARK II reactor facility of the LENA (Laboratorio Energia Nucleare Applicata) Institute of the Pavia University.

  19. Velamo do campo: its volatile constituents, secretory elements, and biological activity.

    PubMed

    El Babili, Fatiha; Roques, Christine; Haddioui, Laila; Bellvert, Floriant; Bertrand, Cédric; Chatelain, Christian

    2012-07-01

    The volatile components from Croton campestris root bark were localized by an anatomical study and analyzed by gas chromatography-mass spectrometry for the first time. The roots of this plant showed secretory cells. These volatile constituents, isolated from the dichloromethane extract by hydrodistillation, were analyzed by gas chromatography-mass spectrometry. We found 69 components. They were characterized, and the major constituents of crude oil root barks were spathulenol (23.3%) and borneol (18.7%). Growth inhibitory activity of the active compounds in solution was evaluated by measuring minimal inhibitory concentrations using a broth micromethod. The minimal inhibitory concentration of root bark volatile constituents was 1.56 μg/mL for Staphylococcus aureus, 3.125 μg/mL for Candida albicans, and 6.25 μg/mL for Aspergillusniger. PMID:22612296

  20. Quantifying crustal response to deep active intrusions with geodesy-based finite element modeling

    NASA Astrophysics Data System (ADS)

    Henderson, S. T.; Pritchard, M. E.; Elliott, J.

    2013-12-01

    The Altiplano-Puna Volcanic Complex (APVC, 21-24 S, 66-69 W) is a first order feature of the Central Andes Volcanic Arc. The APVC consists of over 10,000 km^3 of dacitic ignimbrites deposited in the late Miocene, making it one of the largest concentrations of silicic volcanism in the world. The persistent and intense magmatic flux in this region has likely contributed to the thickened crust (50-70 km), elevated geotherm (>50 C/km) and extensive partial melt (<20 %) inferred under the APVC in modern times. Furthermore, satellite geodetic measurements show surface deformation centered on Uturuncu Volcano (22.27 S, 67.22 W) that is consistent with an ongoing magmatic intrusion in the middle to lower crust. The unique geologic setting and availability of multiple geophysical datasets provide an exceptional opportunity to locate fluid accumulation depths and model the resulting crustal mechanical response. InSAR data between 05/1992 and 01/2011 show that the deformation anomaly is characterized by axis-symmetric constant vertical uplift of 1-10 mm/yr over a radius of 35 km, which is surrounded by 1-4 mm/yr subsidence out to 75 km. One possible explanation for such a signal is diapiric rise of melt from the middle crust. We seek to determine if observed deformation can be alternatively explained by vertical ascent of magma from the lower (~70 km) to middle crust (~20 km). Such a model would be consistent with the short duration of deformation from geomorphic studies (less than 2200 years) and the potential abrupt cessation of uplift seen in a single continuous GPS station starting in 04/2010 near the center of deformation. We therefore test multiple finite element models that match spatial and temporal surface deformation, achieve mass balance between source and sink reservoirs, and require physically realistic rheological parameters of the crust. Modeling is performed with Pylith finite element software on a cylindrical three dimensional domain with a radius of 300 km

  1. Ribosomal frameshifting and dual-target antiactivation restrict quorum-sensing–activated transfer of a mobile genetic element

    PubMed Central

    Ramsay, Joshua P.; Tester, Laura G. L.; Major, Anthony S.; Sullivan, John T.; Edgar, Christina D.; Kleffmann, Torsten; Patterson-House, Jackson R.; Hall, Drew A.; Tate, Warren P.; Hynes, Michael F.; Ronson, Clive W.

    2015-01-01

    Symbiosis islands are integrative and conjugative mobile genetic elements that convert nonsymbiotic rhizobia into nitrogen-fixing symbionts of leguminous plants. Excision of the Mesorhizobium loti symbiosis island ICEMlSymR7A is indirectly activated by quorum sensing through TraR-dependent activation of the excisionase gene rdfS. Here we show that a +1 programmed ribosomal frameshift (PRF) fuses the coding sequences of two TraR-activated genes, msi172 and msi171, producing an activator of rdfS expression named Frameshifted excision activator (FseA). Mass-spectrometry and mutational analyses indicated that the PRF occurred through +1 slippage of the tRNAphe from UUU to UUC within a conserved msi172-encoded motif. FseA activated rdfS expression in the absence of ICEMlSymR7A, suggesting that it directly activated rdfS transcription, despite being unrelated to any characterized DNA-binding proteins. Bacterial two-hybrid and gene-reporter assays demonstrated that FseA was also bound and inhibited by the ICEMlSymR7A-encoded quorum-sensing antiactivator QseM. Thus, activation of ICEMlSymR7A excision is counteracted by TraR antiactivation, ribosomal frameshifting, and FseA antiactivation. This robust suppression likely dampens the inherent biological noise present in the quorum-sensing autoinduction circuit and ensures that ICEMlSymR7A transfer only occurs in a subpopulation of cells in which both qseM expression is repressed and FseA is translated. The architecture of the ICEMlSymR7A transfer regulatory system provides an example of how a set of modular components have assembled through evolution to form a robust genetic toggle that regulates gene transcription and translation at both single-cell and cell-population levels. PMID:25787256

  2. Antagonistic Gene Activities Determine the Formation of Pattern Elements along the Mediolateral Axis of the Arabidopsis Fruit

    PubMed Central

    González-Reig, Santiago; Ripoll, Juan José; Vera, Antonio; Yanofsky, Martin F.; Martínez-Laborda, Antonio

    2012-01-01

    The Arabidopsis fruit mainly consists of a mature ovary that shows three well defined territories that are pattern elements along the mediolateral axis: the replum, located at the medial plane of the flower, and the valve and the valve margin, both of lateral nature. JAG/FIL activity, which includes the combined functions of JAGGED (JAG), FILAMENTOUS FLOWER (FIL), and YABBY3 (YAB3), contributes to the formation of the two lateral pattern elements, whereas the cooperating genes BREVIPEDICELLUS (BP) and REPLUMLESS (RPL) promote replum development. A recent model to explain pattern formation along the mediolateral axis hypothesizes that JAG/FIL activity and BP/RPL function as antagonistic lateral and medial factors, respectively, which tend to repress each other. In this work, we demonstrate the existence of mutual exclusion mechanisms between both kinds of factors, and how this determines the formation and size of the three territories. Medial factors autonomously constrain lateral factors so that they only express outside the replum, and lateral factors negatively regulate the medially expressed BP gene in a non-autonomous fashion to ensure correct replum development. We also have found that ASYMMETRIC LEAVES1 (AS1), previously shown to repress BP both in leaves and ovaries, collaborates with JAG/FIL activity, preventing its repression by BP and showing synergistic interactions with JAG/FIL activity genes. Therefore AS gene function (the function of the interacting genes AS1 and AS2) has been incorporated in the model as a new lateral factor. Our model of antagonistic factors provides explanation for mutant fruit phenotypes in Arabidopsis and also may help to understand natural variation of fruit shape in Brassicaceae and other species, since subtle changes in gene expression may cause conspicuous changes in the size of the different tissue types. PMID:23133401

  3. Soil Moisture and Snow Cover: Active or Passive Elements of Climate

    NASA Technical Reports Server (NTRS)

    Oglesby, Robert J.; Marshall, Susan; Erickson, David J., III; Robertson, Franklin R.; Roads, John O.; Arnold, James E. (Technical Monitor)

    2002-01-01

    A key question is the extent to which surface effects such as soil moisture and snow cover are simply passive elements or whether they can affect the evolution of climate on seasonal and longer time scales. We have constructed ensembles of predictability studies using the NCAR CCM3 in which we compared the relative roles of initial surface and atmospheric conditions over the central and western U.S. in determining the subsequent evolution of soil moisture and of snow cover. Results from simulations with realistic soil moisture anomalies indicate that internal climate variability may be the strongest factor, with some indication that the initial atmospheric state is also important. Model runs with exaggerated soil moisture reductions (near-desert conditions) showed a much larger effect, with warmer surface temperatures, reduced precipitation, and lower surface pressures; the latter indicating a response of the atmospheric circulation. These results suggest the possibility of a threshold effect in soil moisture, whereby an anomaly must be of a sufficient size before it can have a significant impact on the atmospheric circulation and climate. Results from simulations with realistic snow cover anomalies indicate that the time of year can be crucial. When introduced in late winter, these anomalies strongly affected the subsequent evolution of snow cover. When introduced in early winter, however, little or no effect is seen on the subsequent snow cover. Runs with greatly exaggerated initial snow cover indicate that the high reflectivity of snow is the most important process by which snow cover can impact climate, through lower surface temperatures and increased surface pressures. The results to date were obtained for model runs with present-day conditions. We are currently analyzing runs made with projected forcings for the 21st century to see if these results are modified in any way under likely scenarios of future climate change. An intriguing new statistical technique

  4. Identification and characterization of a HeLa nuclear protein that specifically binds to the trans-activation-response (TAR) element of human immunodeficiency virus.

    PubMed Central

    Marciniak, R A; Garcia-Blanco, M A; Sharp, P A

    1990-01-01

    Human immunodeficiency virus type 1 RNAs contain a sequence, trans-activation-response (TAR) element, which is required for tat protein-mediated trans-activation of viral gene expression. We have identified a nuclear protein from extracts of HeLa cells that binds to the TAR element RNA in a sequence-specific manner. The binding of this 68-kDa polypeptide was detected by UV cross-linking proteins to TAR element RNA transcribed in vitro. Competition experiments were performed by using a partially purified preparation of the protein to quantify the relative binding affinities of TAR element RNA mutants. The binding affinity of the TAR mutants paralleled the reported ability of those mutants to support tat trans-activation in vivo. We propose that this cellular protein moderates TAR activity in vivo. Images PMID:2333305

  5. Activation of Phosphatidylinositol-Linked Dopamine Receptors Induces a Facilitation of Glutamate-Mediated Synaptic Transmission in the Lateral Entorhinal Cortex

    PubMed Central

    Glovaci, Iulia; Chapman, C. Andrew

    2015-01-01

    The lateral entorhinal cortex receives strong inputs from midbrain dopamine neurons that can modulate its sensory and mnemonic function. We have previously demonstrated that 1 µM dopamine facilitates synaptic transmission in layer II entorhinal cortex cells via activation of D1-like receptors, increased cAMP-PKA activity, and a resulting enhancement of AMPA-receptor mediated currents. The present study assessed the contribution of phosphatidylinositol (PI)-linked D1 receptors to the dopaminergic facilitation of transmission in layer II of the rat entorhinal cortex, and the involvement of phospholipase C activity and release of calcium from internal stores. Whole-cell patch-clamp recordings of glutamate-mediated evoked excitatory postsynaptic currents were obtained from pyramidal and fan cells. Activation of D1-like receptors using SKF38393, SKF83959, or 1 µM dopamine induced a reversible facilitation of EPSCs which was abolished by loading cells with either the phospholipase C inhibitor U-73122 or the Ca2+ chelator BAPTA. Neither the L-type voltage-gated Ca2+ channel blocker nifedipine, nor the L/N-type channel blocker cilnidipine, blocked the facilitation of synaptic currents. However, the facilitation was blocked by blocking Ca2+ release from internal stores via inositol 1,4,5-trisphosphate (InsP3) receptors or ryanodine receptors. Follow-up studies demonstrated that inhibiting CaMKII activity with KN-93 failed to block the facilitation, but that application of the protein kinase C inhibitor PKC(19-36) completely blocked the dopamine-induced facilitation. Overall, in addition to our previous report indicating a role for the cAMP-PKA pathway in dopamine-induced facilitation of synaptic transmission, we demonstrate here that the dopaminergic facilitation of synaptic responses in layer II entorhinal neurons also relies on a signaling cascade dependent on PI-linked D1 receptors, PLC, release of Ca2+ from internal stores, and PKC activation which is likely dependent

  6. IS1397 is active for transposition into the chromosome of Escherichia coli K-12 and inserts specifically into palindromic units of bacterial interspersed mosaic elements.

    PubMed

    Clément, J M; Wilde, C; Bachellier, S; Lambert, P; Hofnung, M

    1999-11-01

    We demonstrate that IS1397, a putative mobile genetic element discovered in natural isolates of Escherichia coli, is active for transposition into the chromosome of E. coli K-12 and inserts specifically into palindromic units, also called repetitive extragenic palindromes, the basic element of bacterial interspersed mosaic elements (BIMEs), which are found in intergenic regions of enterobacteria closely related to E. coli and Salmonella. We could not detect transposition onto a plasmid carrying BIMEs. This unprecedented specificity of insertion into a well-characterized chromosomal intergenic repeated element and its evolutionary implications are discussed. PMID:10559158

  7. Reactive oxygen species enhance excitatory synaptic transmission in rat spinal dorsal horn neurons by activating TRPA1 and TRPV1 channels.

    PubMed

    Nishio, N; Taniguchi, W; Sugimura, Y K; Takiguchi, N; Yamanaka, M; Kiyoyuki, Yasukuni; Yamada, H; Miyazaki, N; Yoshida, M; Nakatsuka, T

    2013-09-01

    Central neuropathic pain (CNP) in the spinal cord, such as chronic pain after spinal cord injury (SCI), is an incurable ailment. However, little is known about the spinal cord mechanisms underlying CNP. Recently, reactive oxygen species (ROS) have been recognized to play an important role in CNP of the spinal cord. However, it is unclear how ROS affect synaptic transmission in the dorsal horn of the spinal cord. To clarify how ROS impact on synaptic transmission, we investigated the effects of ROS on synaptic transmission in rat spinal cord substantia gelatinosa (SG) neurons using whole-cell patch-clamp recordings. Administration of tert-butyl hydroperoxide (t-BOOH), an ROS donor, into the spinal cord markedly increased the frequency and amplitude of spontaneous excitatory postsynaptic currents (sEPSCs) in SG neurons. This t-BOOH-induced enhancement was not suppressed by the Na(+) channel blocker tetrodotoxin. However, in the presence of a non-N-methyl-D-aspartate glutamate receptor antagonist, 6-cyano-7-nitroquinoxaline-2,3-dione, t-BOOH did not generate any sEPSCs. Furthermore, in the presence of a transient receptor potential ankyrin 1 (TRPA1) channel antagonist (HC-030031) or a transient receptor potential vanilloid 1 (TRPV1) channel antagonist (capsazepine or AMG9810), the t-BOOH-induced increase in the frequency of sEPSCs was inhibited. These results indicate that ROS enhance the spontaneous release of glutamate from presynaptic terminals onto SG neurons through TRPA1 and TRPV1 channel activation. Excessive activation of these ion channels by ROS may induce central sensitization in the spinal cord and result in chronic pain such as that following SCI. PMID:23707800

  8. Amplification of neuromuscular transmission by methylprednisolone involves activation of presynaptic facilitatory adenosine A2A receptors and redistribution of synaptic vesicles.

    PubMed

    Oliveira, L; Costa, A C; Noronha-Matos, J B; Silva, I; Cavalcante, W L G; Timóteo, M A; Corrado, A P; Dal Belo, C A; Ambiel, C R; Alves-do-Prado, W; Correia-de-Sá, P

    2015-02-01

    The mechanisms underlying improvement of neuromuscular transmission deficits by glucocorticoids are still a matter of debate despite these compounds have been used for decades in the treatment of autoimmune myasthenic syndromes. Besides their immunosuppressive action, corticosteroids may directly facilitate transmitter release during high-frequency motor nerve activity. This effect coincides with the predominant adenosine A2A receptor tonus, which coordinates the interplay with other receptors (e.g. muscarinic) on motor nerve endings to sustain acetylcholine (ACh) release that is required to overcome tetanic neuromuscular depression in myasthenics. Using myographic recordings, measurements of evoked [(3)H]ACh release and real-time video microscopy with the FM4-64 fluorescent dye, results show that tonic activation of facilitatory A2A receptors by endogenous adenosine accumulated during 50 Hz bursts delivered to the rat phrenic nerve is essential for methylprednisolone (0.3 mM)-induced transmitter release facilitation, because its effect was prevented by the A2A receptor antagonist, ZM 241385 (10 nM). Concurrent activation of the positive feedback loop operated by pirenzepine-sensitive muscarinic M1 autoreceptors may also play a role, whereas the corticosteroid action is restrained by the activation of co-expressed inhibitory M2 and A1 receptors blocked by methoctramine (0.1 μM) and DPCPX (2.5 nM), respectively. Inhibition of FM4-64 loading (endocytosis) by methylprednisolone following a brief tetanic stimulus (50 Hz for 5 s) suggests that it may negatively modulate synaptic vesicle turnover, thus increasing the release probability of newly recycled vesicles. Interestingly, bulk endocytosis was rehabilitated when methylprednisolone was co-applied with ZM241385. Data suggest that amplification of neuromuscular transmission by methylprednisolone may involve activation of presynaptic facilitatory adenosine A2A receptors by endogenous adenosine leading to synaptic

  9. Soil Moisture and Snow Cover: Active or Passive Elements of Climate?

    NASA Technical Reports Server (NTRS)

    Oglesby, Robert J.; Marshall, Susan; Erickson, David J., III; Robertson, Franklin R.; Roads, John O.; Arnold, James E. (Technical Monitor)

    2002-01-01

    A key question in the study of the hydrologic cycle is the extent to which surface effects such as soil moisture and snow cover are simply passive elements or whether they can affect the evolution of climate on seasonal and longer time scales. We have constructed ensembles of predictability studies using the NCAR CCM3 in which we compared the relative roles of initial surface and atmospheric conditions over the central and western U.S. in determining the subsequent evolution of soil moisture and of snow cover. We have also made sensitivity studies with exaggerated soil moisture and snow cover anomalies in order to determine the physical processes that may be important. Results from simulations with realistic soil moisture anomalies indicate that internal climate variability may be the strongest factor, with some indication that the initial atmospheric state is also important. The initial state of soil moisture does not appear important, a result that held whether simulations were started in late winter or late spring. Model runs with exaggerated soil moisture reductions (near-desert conditions) showed a much larger effect, with warmer surface temperatures, reduced precipitation, and lower surface pressures; the latter indicating a response of the atmospheric circulation. These results suggest the possibility of a threshold effect in soil moisture, whereby an anomaly must be of a sufficient size before it can have a significant impact on the atmospheric circulation and hence climate. Results from simulations with realistic snow cover anomalies indicate that the time of year can be crucial. When introduced in late winter, these anomalies strongly affected the subsequent evolution of snow cover. When introduced in early winter, however, little or no effect is seen on the subsequent snow cover. Runs with greatly exaggerated initial snow cover indicate that the high reflectively of snow is the most important process by which snow cover cart impact climate, through lower

  10. Soil Moisture and Snow Cover: Active or Passive Elements of Climate?

    NASA Technical Reports Server (NTRS)

    Oglesby, Robert J.; Marshall, Susan; Robertson, Franklin R.; Roads, John O.; Arnold, James E. (Technical Monitor)

    2001-01-01

    A key question in the study of the hydrologic cycle is the extent to which surface effects such as soil moisture and snow cover are simply passive elements or whether they can affect the evolution of climate on seasonal and longer time scales. We have constructed ensembles of predictability studies using the NCAR CCM3 in which we compared the relative roles of initial surface and atmospheric conditions over the central and western U.S. GAPP region in determining the subsequent evolution of soil moisture and of snow cover. We have also made sensitivity studies with exaggerated soil moisture and snow cover anomalies in order to determine the physical processes that may be important. Results from simulations with realistic soil moisture anomalies indicate that internal climate variability may be the strongest factor, with some indication that the initial atmospheric state is also important. The initial state of soil moisture does not appear important, a result that held whether simulations were started in late winter or late spring. Model runs with exaggerated soil moisture reductions (near-desert conditions) showed a much larger effect, with warmer surface temperatures, reduced precipitation, and lower surface pressures; the latter indicating a response of the atmospheric circulation. These results suggest the possibility of a threshold effect in soil moisture, whereby an anomaly must be of a sufficient size before it can have a significant impact on the atmospheric circulation and hence climate. Results from simulations with realistic snow cover anomalies indicate that the time of year can be crucial. When introduced in late winter, these anomalies strongly affected the subsequent evolution of snow cover. When introduced in early winter, however, little or no effect is seen on the subsequent snow cover. Runs with greatly exaggerated initial snow cover indicate that the high reflectivity of snow is the most important process by which snow cover can impact climate

  11. Distinct sequence elements control the specificity of G protein activation by muscarinic acetylcholine receptor subtypes.

    PubMed Central

    Lechleiter, J; Hellmiss, R; Duerson, K; Ennulat, D; David, N; Clapham, D; Peralta, E

    1990-01-01

    Relatively little is understood concerning the mechanisms by which subtypes of receptors, G proteins and effector enzymes interact to transduce specific signals. Through expression of normal, hybrid and deletion mutant receptors in Xenopus oocytes, we determined the G protein coupling characteristics of the functionally distinct m2 and m3 muscarinic acetylcholine receptor (mAChR) subtypes and identified the critical receptor sequences responsible for G protein specificity. Activation of a pertussis toxin insensitive G protein pathway, leading to a rapid and transient release of intracellular Ca2+ characteristic of the m3 receptor, could be specified by the transfer of as few as nine amino acids from the m3 to the m2 receptor. In a reciprocal manner, transfer of no more than 21 residues from the m2 to the m3 receptor was sufficient to specify activation of a pertussis toxin sensitive G protein coupled to a slow and oscillatory Ca2+ release pathway typical of the m2 subtype. Notably, these critical residues occur within the same region of the third cytoplasmic domain of functionally distinct mAChR subtypes. Images Fig. 1. Fig. 2. Fig. 4. Fig. 5. PMID:2124972

  12. Finite element simulations of the active stress in the imaginal disc of the Drosophila Melanogaster.

    PubMed

    Pettinati, V; Ambrosi, D; Ciarletta, P; Pezzuto, S

    2016-09-01

    During the larval stages of development, the imaginal disc of Drosphila Melanogaster is composed by a monolayer of epithelial cells, which undergo a strain actively produced by the cells themselves. The well-organized collective contraction produces a stress field that seemingly has a double morphogenetic role: it orchestrates the cellular organization towards the macroscopic shape emergence while simultaneously providing a local information on the organ size. Here we perform numerical simulations of such a mechanical control on morphogenesis at a continuum level, using a three-dimensional finite model that accounts for the active cell contraction. The numerical model is able to reproduce the (few) known qualitative characteristics of the tensional patterns within the imaginal disc of the fruit fly. The computed stress components slightly deviate from planarity, thus confirming the previous theoretical assumptions of a nonlinear elastic analytical model, and enforcing the hypothesis that the spatial variation of the mechanical stress may act as a size regulating signal that locally scales with the global dimension of the domain. PMID:26765274

  13. Covalent Inhibition of Ubc13 Affects Ubiquitin Signaling and Reveals Active Site Elements Important for Targeting

    PubMed Central

    Hodge, Curtis D.; Edwards, Ross A.; Markin, Craig J.; McDonald, Darin; Pulvino, Mary; Huen, Michael S. Y.; Zhao, Jiyong; Spyracopoulos, Leo; Hendzel, Michael J.; Glover, J.N. Mark

    2015-01-01

    Ubc13 is an E2 ubiquitin conjugating enzyme that functions in nuclear DNA damage signaling and cytoplasmic NF-κB signaling. Here we present the structures of complexes of Ubc13 with two inhibitors, NSC697923 and BAY 11-7082, which inhibit DNA damage and NF-κB signaling in human cells. NSC697923 and BAY 11-7082 both inhibit Ubc13 by covalent adduct formation through a Michael addition at the Ubc13 active site cysteine. The resulting adducts of both compounds exploit a binding groove unique to Ubc13. We developed a Ubc13 mutant which resists NSC697923 inhibition and, using this mutant, we show that the inhibition of cellular DNA damage and NF-κB signaling by NSC697923 is largely due to specific Ubc13 inhibition. We propose that unique structural features near the Ubc13 active site could provide a basis for the rational development and design of specific Ubc13 inhibitors. PMID:25909880

  14. Covalent Inhibition of Ubc13 Affects Ubiquitin Signaling and Reveals Active Site Elements Important for Targeting.

    PubMed

    Hodge, Curtis D; Edwards, Ross A; Markin, Craig J; McDonald, Darin; Pulvino, Mary; Huen, Michael S Y; Zhao, Jiyong; Spyracopoulos, Leo; Hendzel, Michael J; Glover, J N Mark

    2015-07-17

    Ubc13 is an E2 ubiquitin conjugating enzyme that functions in nuclear DNA damage signaling and cytoplasmic NF-κB signaling. Here, we present the structures of complexes of Ubc13 with two inhibitors, NSC697923 and BAY 11-7082, which inhibit DNA damage and NF-κB signaling in human cells. NSC697923 and BAY 11-7082 both inhibit Ubc13 by covalent adduct formation through a Michael addition at the Ubc13 active site cysteine. The resulting adducts of both compounds exploit a binding groove unique to Ubc13. We developed a Ubc13 mutant which resists NSC697923 inhibition and, using this mutant, we show that the inhibition of cellular DNA damage and NF-κB signaling by NSC697923 is largely due to specific Ubc13 inhibition. We propose that unique structural features near the Ubc13 active site could provide a basis for the rational development and design of specific Ubc13 inhibitors. PMID:25909880

  15. Structural Elements and Cough Suppressing Activity of Polysaccharides from Zingiber officinale Rhizome.

    PubMed

    Bera, K; Nosalova, G; Sivova, V; Ray, B

    2016-01-01

    Zingiber officinale is used for the management of fever, bronchial asthma and cough for thousands of years. While the link to a particular indication has been established in human, the active principle of the formulation remains unknown. Herein, we have investigated a water extracted polysaccharides (WEP) containing fraction from its rhizome. Utilizing a traditional aqueous extraction protocol and using chemical, chromatographic and spectroscopic methods a fraction containing a branched glucan and polygalaturonan in a ratio of 59:1 was characterized. This glucan, which has a molecular mass of 36 kDa, is made up of terminal-, (1,4)- and (1,4,6)-linked α-Glcp residues. Oral administration of WEP in doses of 25 and 50 mg/kg body weight significantly inhibited the number of citric acid-induced cough efforts in guinea pigs. It does not alter the specific airway smooth muscle reactivity significantly. Thus, traditional aqueous extraction method provides molecular entities, which induces antitussive activity without addiction. PMID:26522239

  16. The Azorhizobium caulinodans nifA gene: identification of upstream-activating sequences including a new element, the 'anaerobox'.

    PubMed Central

    Nees, D W; Stein, P A; Ludwig, R A

    1988-01-01

    From nucleotide sequencing analyses, the A. caulinodans nifA gene seems to be under dual control by the Ntr (in response to available N) and Fnr (in response to available O2) transcriptional activation/repression systems. Because it fixes N2 in two contexts, the Ntr system might regulate A. caulinodans nif gene expression ex planta, while the Fnr system might similarly regulate in planta. As nifA upstream-activating elements, we have identified: (i) a gpNifA binding site allowing autogenous nifA regulation, (ii) an Ntr-dependent transcription start, presumably the target of gpNifA activation, and (iii) an "anaerobox" tetradecameric nucleotide sequence that is precisely conserved among O2 regulated enteric bacterial genes controlled by the gpFnr transcriptional activator. Because it is precisely positioned upstream of enteric bacterial transcriptional starts, the "anaerobox" sequence may constitute the gpFnr DNA binding site. If so, then a second, Ntr-independent nifA transcription start may exist. We have also deduced the A. caulinodans nifA open reading frame and have compared the gene product (gpNifA) with those of other N2-fixing organisms. These proteins exhibit strongly conserved motifs: (i) sites conserved among ATP-binding proteins, (ii) an interdomain linker region, and (iii) a C-terminal alpha-helix-turn-alpha-helix DNA binding site. PMID:3186446

  17. Enhancing active and passive remote sensing in the ocean using broadband acoustic transmissions and coherent hydrophone arrays

    NASA Astrophysics Data System (ADS)

    Tran, Duong Duy

    The statistics of broadband acoustic signal transmissions in a random continental shelf waveguide are characterized for the fully saturated regime. The probability distribution of broadband signal energies after saturated multi-path propagation is derived using coherence theory. The frequency components obtained from Fourier decomposition of a broadband signal are each assumed to be fully saturated, where the energy spectral density obeys the exponential distribution with 5.6 dB standard deviation and unity scintillation index. When the signal bandwidth and measurement time are respectively larger than the correlation bandwidth and correlation time of its energy spectral density components, the broadband signal energy obtained by integrating the energy spectral density across the signal bandwidth then follows the Gamma distribution with standard deviation smaller than 5.6 dB and scintillation index less than unity. The theory is verified with broadband transmissions in the Gulf of Maine shallow water waveguide in the 300-1200 Hz frequency range. The standard deviations of received broadband signal energies range from 2.7 to 4.6 dB for effective bandwidths up to 42 Hz, while the standard deviations of individual energy spectral density components are roughly 5.6 dB. The energy spectral density correlation bandwidths of the received broadband signals are found to be larger for signals with higher center frequency. Sperm whales in the New England continental shelf and slope were passively localized, in both range and bearing using a single low-frequency (< 2500 Hz), densely sampled, towed horizontal coherent hydrophone array system. Whale bearings were estimated using time-domain beamforming that provided high coherent array gain in sperm whale click signal-to-noise ratio. Whale ranges from the receiver array center were estimated using the moving array triangulation technique from a sequence of whale bearing measurements. The dive profile was estimated for a sperm

  18. p75 Neurotrophin Receptor Signaling Activates Sterol Regulatory Element-binding Protein-2 in Hepatocyte Cells via p38 Mitogen-activated Protein Kinase and Caspase-3.

    PubMed

    Pham, Dan Duc; Do, Hai Thi; Bruelle, Céline; Kukkonen, Jyrki P; Eriksson, Ove; Mogollón, Isabel; Korhonen, Laura T; Arumäe, Urmas; Lindholm, Dan

    2016-05-13

    Nerve growth factor (NGF) influences the survival and differentiation of a specific population of neurons during development, but its role in non-neuronal cells has been less studied. We observed here that NGF and its pro-form, pro-NGF, are elevated in fatty livers from leptin-deficient mice compared with controls, concomitant with an increase in low density lipoprotein receptors (LDLRs). Stimulation of mouse primary hepatocytes with NGF or pro-NGF increased LDLR expression through the p75 neurotrophin receptor (p75NTR). Studies using Huh7 human hepatocyte cells showed that the neurotrophins activate the sterol regulatory element-binding protein-2 (SREBP2) that regulates genes involved in lipid metabolism. The mechanisms for this were related to stimulation of p38 mitogen-activated protein kinase (p38 MAPK) and activation of caspase-3 and SREBP2 cleavage following NGF and pro-NGF stimulations. Cell fractionation experiments showed that caspase-3 activity was increased particularly in the membrane fraction that harbors SREBP2 and caspase-2. Experiments showed further that caspase-2 interacts with pro-caspase-3 and that p38 MAPK reduced this interaction and caused caspase-3 activation. Because of the increased caspase-3 activity, the cells did not undergo cell death following p75NTR stimulation, possibly due to concomitant activation of nuclear factor-κB (NF-κB) pathway by the neurotrophins. These results identify a novel signaling pathway triggered by ligand-activated p75NTR that via p38 MAPK and caspase-3 mediate the activation of SREBP2. This pathway may regulate LDLRs and lipid uptake particularly after injury or during tissue inflammation accompanied by an increased production of growth factors, including NGF and pro-NGF. PMID:26984409

  19. A 3'UTR pumilio-binding element directs translational activation in olfactory sensory neurons.

    PubMed

    Kaye, Julia A; Rose, Natalie C; Goldsworthy, Brett; Goga, Andrei; L'Etoile, Noelle D

    2009-01-15

    Prolonged stimulation leads to specific and stable changes in an animal's behavior. In interneurons, this plasticity requires spatial and temporal control of neuronal protein synthesis. Whether such translational control occurs in sensory neurons is not known. Adaptation of the AWC olfactory sensory neurons of C. elegans requires the cGMP-dependent protein kinase EGL-4. Here, we show that the RNA-binding PUF protein FBF-1 is required in the adult AWC for adaptation. In the odor-adapted animal, it increases translation via binding to the egl-4 3' UTR. Further, the PUF protein may localize translation near the sensory cilia and cell body. Although the RNA-binding PUF proteins have been shown to promote plasticity in development by temporally and spatially repressing translation, this work reveals that in the adult nervous system, they can work in a different way to promote experience-dependent plasticity by activating translation in response to environmental stimulation. PMID:19146813

  20. Comprehensive quantification of tablets with multiple active pharmaceutical ingredients using transmission Raman spectroscopy--a proof of concept study.

    PubMed

    Griffen, Julia; Owen, Andrew; Matousek, Pavel

    2015-11-10

    Transmission Raman spectroscopy is a potent new tool for content uniformity testing in pharmaceutical manufacturing enabling rapid bulk sampling of a material by non-destructive means. In this proof-of-concept study, we present, for the first time, comprehensive quantification of all the constituents in a set of tablets consisting of 5 components (3 APIs and 2 excipients) by this method. The nominal concentration of individual components ranged from 1 to 85% (w/w). Two multivariate partial least-squares approaches have been used to calibrate concentration models consisting of 40 handmade tablets covering 20 sample points. These models successfully predicted all the components in a set of 10 validation tablets covering 5 different sample points. A single model for all components (PLS2) and 5 individual models each optimised for one component (PLS1) performed similarity and have been used to demonstrate that specificity of prediction has been achieved through using a multifactor orthogonal DoE for sample preparation. The ability to determine multiple analyte concentrations in one single measurement further establishes this procedure and its benefits for assay and content uniformity testing. PMID:26263055