WorldWideScience

Sample records for probing residue-specific interactions

  1. Probing kink interactions with fermions

    International Nuclear Information System (INIS)

    Carlitz, R.; Chakrabarti, R.

    1985-01-01

    A dilute gas of kinks exhibits strong but short-ranged intrinsic interactions. When these intrinsic interactions are supplemented by other ''extrinsic'' interactions, a phase transition can occur in which kinks and antikinks bind to form a gas of bounces. The extrinsic interactions arise from the coupling of kinks to an additional degree of freedom, which we take to be a fermion field. The class of quantum-mechanical models which we study includes examples of supersymmetry. The way in which kinks and antikinks bind depends in detail on aspects of the intrinsic interactions. This structure is probably shared by field-theoretic models

  2. Sedentary behavior and residual-specific mortality

    OpenAIRE

    Paul D. Loprinzi; Meghan K. Edwards; Eveleen Sng; Ovuokerie Addoh

    2016-01-01

    Background: The purpose of this study was to examine the association of accelerometer-assessed sedentary behavior and residual-specific mortality. Methods: Data from the 2003-2006 National Health and Nutrition Examination Survey (NHANES) were used (N = 5536), with follow-up through 2011. Sedentary behavior was objectively measured over 7 days via accelerometry. Results: When expressing sedentary behavior as a 60 min/day increase, the hazard ratio across the models ranged from 1.07-1.40 (P < 0...

  3. Depletion interaction measured by colloidal probe atomic force microscopy

    NARCIS (Netherlands)

    Wijting, W.K.; Knoben, W.; Besseling, N.A.M.; Leermakers, F.A.M.; Cohen Stuart, M.A.

    2004-01-01

    We investigated the depletion interaction between stearylated silica surfaces in cyclohexane in the presence of dissolved polydimethylsiloxane by means of colloidal probe atomic force microscopy. We found that the range of the depletion interaction decreases with increasing concentration.

  4. Muons as hyperfine interaction probes in chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Ghandi, Khashayar, E-mail: kghandi@triumf.ca; MacLean, Amy [Mount Allison University, Department of Chemistry & Biochemistry (Canada)

    2015-04-15

    Spin polarized positive muons injected in matter serve as magnetic probes for the investigation of physical and chemical properties of free radicals, mechanisms of free radical reactions and their formations, and radiation effects. All muon techniques rely on the evolution of spin polarization (of the muon) and in that respect are similar to conventional magnetic resonance techniques. The applications of the muon as a hyperfine probe in several fields in chemistry are described.

  5. Muons as hyperfine interaction probes in chemistry

    International Nuclear Information System (INIS)

    Ghandi, Khashayar; MacLean, Amy

    2015-01-01

    Spin polarized positive muons injected in matter serve as magnetic probes for the investigation of physical and chemical properties of free radicals, mechanisms of free radical reactions and their formations, and radiation effects. All muon techniques rely on the evolution of spin polarization (of the muon) and in that respect are similar to conventional magnetic resonance techniques. The applications of the muon as a hyperfine probe in several fields in chemistry are described

  6. Probing gas-surface interactions with a molecular beam

    International Nuclear Information System (INIS)

    Spruit, M.E.M.

    1988-01-01

    The dynamics of direct scattering, trapping and sticking in molecular beam scattering is probed. The O 2 /Ag interaction was chosen, using the close-packed (111) plane of Ag as target surface. 170 refs.; 22 figs.; 3 tabs

  7. Probing Pseudomonas syringae host interactions using metatranscriptomics

    Science.gov (United States)

    Transcriptome analyses during the interaction of plants and pathogens can be used to provide insights into molecular mechanisms of plant resistance as well as the mechanisms used by bacteria to adapt to hosts and cause disease. We performed a dual in planta RNA-Seq experiment to profile RNA expressi...

  8. Electromagnetic probes of strongly interacting matter

    Indian Academy of Sciences (India)

    2015-05-07

    May 7, 2015 ... Collisions between two nuclei at relativistic energies will create charged particles – either in .... The thermal cutting rules give a systematic procedure to express ...... mesons due to its interaction with the thermal partons [80] and employment of running .... [16] J Deng, Q Wang, N Xu and P Zhuang, Phys. Lett.

  9. Optically Levitated Microspheres as a Probe for New Interactions

    Science.gov (United States)

    Rider, Alexander; Moore, David; Blakemore, Charles; Lu, Marie; Gratta, Giorgio

    2016-03-01

    We are developing novel techniques to probe new interactions at micron distances using optically levitated dielectric microspheres. Levitated microspheres are an ideal probe for short-range interactions because they are suspended using the radiation pressure at the focus of a laser beam, which means that the microspheres can be precisely manipulated and isolated from the surrounding environment at high vacuum. We have performed a search for unknown charged particles bound within the bulk of the microspheres. Currently, we are searching for the presence of a Chameleon field postulated to explain the presence of dark energy in the universe. In the future we plan to use optically levitated microspheres to search for micron length-scale gravity like interactions that could couple between a microsphere and another mass. We will present resent results from these experiments and plans for future searches for new interactions.

  10. Probing Nanoscale Electronic and Magnetic Interaction with Scanning Tunneling Spectroscopy

    DEFF Research Database (Denmark)

    Bork, Jakob

    tunneling microscope (STM). Especially at low temperatures the Kondo resonance is used to probe magnetic interaction with ferromagnetic islands and between two atoms. The latter showing a crossover between Kondo screened atoms and antiferromagnetically coupled atoms close to the quantum critical point....... This is related to research in correlated electron materials such as studies of phase transitions in heavy fermion compounds and magnetic interaction in spintronic research. The capping of cobalt islands on Cu(111) with silver is investigated with STM and photoemission spectroscopy. It is shown that at low...

  11. Probing Quark-Gluon Interactions with Transverse Polarized Scattering

    International Nuclear Information System (INIS)

    Rondon, Oscar A.

    2011-01-01

    Transverse polarized inelastic scattering extends the power of the electromagnetic interaction as a probe of nucleon dynamics beyond the leading order regime explored with longitudinally polarized DIS. In transverse polarized scattering, the twist-3 g 2 spin structure function contributes at the same order as the longitudinal, twist-2, g 1 , so interactions between quarks and gluons can be studied, opening a window on the mechanisms of confinement. This talk reports the results of Jefferson Lab's Resonances Spin Structure experiment measurement of g 2 and the d 2 twist-3 quark matrix element at a four-momentum transfer of 1.3 GeV 2 .

  12. Simulated galaxy interactions as probes of merger spectral energy distributions

    Energy Technology Data Exchange (ETDEWEB)

    Lanz, Lauranne; Zezas, Andreas; Smith, Howard A.; Ashby, Matthew L. N.; Fazio, Giovanni G.; Hernquist, Lars [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Hayward, Christopher C. [Heidelberger Institut für Theoretische Studien, Schloss-Wolfsbrunnenweg 35, D-69118 Heidelberg (Germany); Brassington, Nicola, E-mail: llanz@ipac.caltech.edu [School of Physics, Astronomy and Mathematics, University of Hertfordshire, College Lane, Hatfield, AL10 9AB (United Kingdom)

    2014-04-10

    We present the first systematic comparison of ultraviolet-millimeter spectral energy distributions (SEDs) of observed and simulated interacting galaxies. Our sample is drawn from the Spitzer Interacting Galaxy Survey and probes a range of galaxy interaction parameters. We use 31 galaxies in 14 systems which have been observed with Herschel, Spitzer, GALEX, and 2MASS. We create a suite of GADGET-3 hydrodynamic simulations of isolated and interacting galaxies with stellar masses comparable to those in our sample of interacting galaxies. Photometry for the simulated systems is then calculated with the SUNRISE radiative transfer code for comparison with the observed systems. For most of the observed systems, one or more of the simulated SEDs match reasonably well. The best matches recover the infrared luminosity and the star formation rate of the observed systems, and the more massive systems preferentially match SEDs from simulations of more massive galaxies. The most morphologically distorted systems in our sample are best matched to the simulated SEDs that are close to coalescence, while less evolved systems match well with the SEDs over a wide range of interaction stages, suggesting that an SED alone is insufficient for identifying the interaction stage except during the most active phases in strongly interacting systems. This result is supported by our finding that the SEDs calculated for simulated systems vary little over the interaction sequence.

  13. Retarded Local Dynamics of Single Fluorescent Probes in Polymeric Glass due to Interaction Strengthening

    Science.gov (United States)

    Zhang, Hao; Yang, Jingfa; Zhao, Jiang

    The effect of strengthening of interaction between single fluorescent probes and polymer matrix to the probes dynamics is investigated using single molecule fluorescence defocus microscopy. By introducing multiple hydroxyl groups to the fluorescent probes, which builds up hydrogen bonds between the probe and polymer matrix, the dynamics is discovered to be retarded. This is evidenced by the lowering of the frequency of the vibrational modes in the power spectra of the rotation trajectories of individual fluorescent probes, and also by the lowering of population of rotating probes. The results show that by strengthening the probe-matrix interaction, the local dynamics detected by the probes is equivalent to that detected by a bigger probe, due to the enhanced friction between the probe and the polymer matrix. the National Basic Research Program of China (2012CB821500).

  14. Probing hydrogen bonding interactions and proton transfer in proteins

    Science.gov (United States)

    Nie, Beining

    Scope and method of study. Hydrogen bonding is a fundamental element in protein structure and function. Breaking a single hydrogen bond may impair the stability of a protein. It is therefore important to probe dynamic changes in hydrogen bonding interactions during protein folding and function. Time-resolved Fourier transform infrared spectroscopy is highly sensitive to hydrogen bonding interactions. However, it lacks quantitative correlation between the vibrational frequencies and the number, type, and strength of hydrogen bonding interactions of ionizable and polar residues. We employ quantum physics theory based ab initio calculations to study the effects of hydrogen bonding interactions on vibrational frequencies of Asp, Glu, and Tyr residues and to develop vibrational spectral markers for probing hydrogen bonding interactions using infrared spectroscopy. In addition, proton transfer process plays a crucial role in a wide range of energy transduction, signal transduction, and enzymatic reactions. We study the structural basis for proton transfer using photoactive yellow protein as an excellent model system. Molecular dynamics simulation is employed to investigate the structures of early intermediate states. Quantum theory based ab initio calculations are used to study the impact of hydrogen bond interactions on proton affinity and proton transfer. Findings and conclusions. Our extensive density function theory based calculations provide rich structural, spectral, and energetic information on hydrogen bonding properties of protonated side chain groups of Asp/Glu and Tyr. We developed vibrational spectral markers and 2D FTIR spectroscopy for structural characterization on the number and the type of hydrogen bonding interactions of the COOH group of Asp/Glu and neutral phenolic group of Tyr. These developments greatly enhance the power of time-resolved FTIR spectroscopy as a major experimental tool for structural characterization of functionally important

  15. Molecular electrostatics for probing lone pair-π interactions.

    Science.gov (United States)

    Mohan, Neetha; Suresh, Cherumuttathu H; Kumar, Anmol; Gadre, Shridhar R

    2013-11-14

    An electrostatics-based approach has been proposed for probing the weak interactions between lone pair containing molecules and π deficient molecular systems. For electron-rich molecules, the negative minima in molecular electrostatic potential (MESP) topography give the location of electron localization and the MESP value at the minimum (Vmin) quantifies the electron-rich character of that region. Interactive behavior of a lone pair bearing molecule with electron deficient π-systems, such as hexafluorobenzene, 1,3,5-trinitrobenzene, 2,4,6-trifluoro-1,3,5-triazine and 1,2,4,5-tetracyanobenzene explored within DFT brings out good correlation of the lone pair-π interaction energy (E(int)) with the Vmin value of the electron-rich system. Such interaction is found to be portrayed well with the Electrostatic Potential for Intermolecular Complexation (EPIC) model. On the basis of the precise location of MESP minimum, a prediction for the orientation of a lone pair bearing molecule with an electron deficient π-system is possible in the majority of the cases studied.

  16. Probe DNA-Cisplatin Interaction with Solid-State Nanopores

    Science.gov (United States)

    Zhou, Zhi; Hu, Ying; Li, Wei; Xu, Zhi; Wang, Pengye; Bai, Xuedong; Shan, Xinyan; Lu, Xinghua; Nanopore Collaboration

    2014-03-01

    Understanding the mechanism of DNA-cisplatin interaction is essential for clinical application and novel drug design. As an emerging single-molecule technology, solid-state nanopore has been employed in biomolecule detection and probing DNA-molecule interactions. Herein, we reported a real-time monitoring of DNA-cisplatin interaction by employing solid-state SiN nanopores. The DNA-cisplatin interacting process is clearly classified into three stages by measuring the capture rate of DNA-cisplatin adducts. In the first stage, the negative charged DNA molecules were partially discharged due to the bonding of positive charged cisplatin and forming of mono-adducts. In the second stage, forming of DNA-cisplatin di-adducts with the adjacent bases results in DNA bending and softening. The capture rate increases since the softened bi-adducts experience a lower barrier to thread into the nanopores. In the third stage, complex structures, such as micro-loop, are formed and the DNA-cisplatin adducts are aggregated. The capture rate decreases to zero as the aggregated adduct grows to the size of the pore. The characteristic time of this stage was found to be linear with the diameter of the nanopore and this dynamic process can be described with a second-order reaction model. We are grateful to Laboratory of Microfabrication, Dr. Y. Yao, and Prof. R.C. Yu (Institute of Physics, Chinese Academy of Sciences) for technical assistance.

  17. Wide-Range Probing of Dzyaloshinskii-Moriya Interaction

    Science.gov (United States)

    Kim, Duck-Ho; Yoo, Sang-Cheol; Kim, Dae-Yun; Min, Byoung-Chul; Choe, Sug-Bong

    2017-03-01

    The Dzyaloshinskii-Moriya interaction (DMI) in magnetic objects is of enormous interest, because it generates built-in chirality of magnetic domain walls (DWs) and topologically protected skyrmions, leading to efficient motion driven by spin-orbit torques. Because of its importance for both potential applications and fundamental research, many experimental efforts have been devoted to DMI investigation. However, current experimental probing techniques cover only limited ranges of the DMI strength and have specific sample requirements. Thus, there are no versatile methods to quantify DMI over a wide range of values. Here, we present such an experimental scheme, which is based on the angular dependence of asymmetric DW motion. This method can be used to determine values of DMI much larger than the maximum strength of the external magnetic field strength, which demonstrates that various DMI strengths can be quantified with a single measurement setup. This scheme may thus prove essential to DMI-related emerging fields in nanotechnology.

  18. Capillary Interactions between a Probe Tip and a Nanoparticle

    International Nuclear Information System (INIS)

    Li-Ning, Sun; Le-Feng, Wang; Wei-Bin, Rong

    2008-01-01

    To understand capillary interactions between probe tips and nanoparticles under ambient conditions, a theoretical model of capillary forces between them is developed based on the geometric relations. It is found that the contribution of surface tension force to the total capillary force attains to similar order of magnitude as the capillary pressure force in many cases. It is also shown that the tip shape and the radial distance of the meniscus have great influence on the capillary force. The capillary force decreases with the increasing separation distances, and the variance of the contact angles may change the magnitudes of capillary forces several times at large radial distances. The applicability of the symmetric meniscus approximation is discussed. (condensed matter: structure, mechanical and thermal properties)

  19. Diffusing colloidal probes of protein-carbohydrate interactions.

    Science.gov (United States)

    Eichmann, Shannon L; Meric, Gulsum; Swavola, Julia C; Bevan, Michael A

    2013-02-19

    We present diffusing colloidal probe measurements of weak, multivalent, specific protein-polysaccharide interactions mediated by a competing monosaccharide. Specifically, we used integrated evanescent wave and video microscopy methods to monitor the three-dimensional Brownian excursions of conconavilin A (ConA) decorated colloids interacting with dextran-functionalized surfaces in the presence of glucose. Particle trajectories were interpreted as binding lifetime histograms, binding isotherms, and potentials of mean force. Binding lifetimes and isotherms showed clear trends of decreasing ConA-dextran-specific binding with increasing glucose concentration, consistent with expectations. Net potentials were accurately captured by superposition of a short-range, glucose-independent ConA-dextran repulsion and a longer-range, glucose-dependent dextran bridging attraction modeled as a harmonic potential. For glucose concentrations greater than 100 mM, the net ConA-dextran potential was found to have only a nonspecific repulsion, similar to that of bovine serum albumin (BSA) decorated colloids over dextran determined in control experiments. Our results demonstrate the first use of optical microscopy methods to quantify the connections between potentials of mean force and the binding behavior of ConA-decorated colloids on dextran-functionalized surfaces.

  20. Interaction of a ballistic probe with gaseous media

    International Nuclear Information System (INIS)

    Kucerovsky, Zden; Greason, William D

    2008-01-01

    Free-flying metal probes are used to determine charge densities in gaseous media containing free charge or low density plasma. The trajectory of the probe is ensured either by gravity or by propelling the probe to a certain velocity at the launch site. While travelling, the probe charge changes from its launch-site magnitude to that related to the space charge density existing along the trajectory. The degree to which the probe's arrival-site charge magnitude matches the space charge density in the area of interest depends on the probe shape and on the charge exchange processes between the probe body and the medium. The paper studies a probe acting as a free-flying charge carrier in air, and discusses the problems that may lead to an imbalance between the charge collected by the probe in the area of interest and the charge measured at the arrival site. The analysis and the described experiments are of the ballistic type: a small, triboelectrically pre-charged metal probe was propelled on a horizontal path, and the charge carried by the probe was measured at several points along the trajectory by means of contact-free induction rings; the initial and final charges were determined by static Faraday cups. A charge disparity was found under certain conditions, and its degree explained by the effects of the charge carrier potential. The studied probe charges ranged from 10 to 50 nF, and the fly-times needed to cross a one-meter path ranged from 20 to 40 ms. The probe to gas charge exchange experiments and their analysis yielded conditions under which the probe lost approximately 10 % of its charge. The results of our study may be of interest to those who intend to use the free-flying probe technique for the determination of space charge density.

  1. Organizational Probes:Exploring Playful Interactions in Work Environment

    NARCIS (Netherlands)

    Vyas, Dhaval; Eliens, A.P.W.; Eliëns, A.; van de Watering, M.R.; van der Veer, Gerrit C.; Jorge, J

    2008-01-01

    Playfulness, with non-intrusive elements, can be considered a useful resource for enhancing social awareness and community building within work organizations. Taking inspirations from the cultural probes approach, we developed organizational probes as a set of investigation tools that could provide

  2. Probing the pairing interaction through two-neutron transfer reactions

    Directory of Open Access Journals (Sweden)

    Margueron J.

    2012-12-01

    Full Text Available The treatment of the pairing interaction in mean-field-based models is addressed. In particular, the possibility to use pair transfers as A tool to better constrain this interaction is discussed. First, pairing inter-actions with various density dependencies (surface/volume mixing are used in the microscopic Hartree-Fock-Bogoliubov + quasiparticle random-phase approximation model to generate the form factors to be used in reaction calculations. Cross sections for (p,t two-neutron transfer reactions are calculated in the one-step zero-range distorted-wave Born approximation for some Tin isotopes and for incident proton energies from 15 to 35 MeV. Three different surface/volume mixings of A zero-range density-dependent pairing interaction are employed in the microscopic calculations and the sensitivity of the cross sections to the different mixings is analyzed. Differences among the three different theoretical predictions are found espacially for the nucleus 136Sn and they are more important at the incident proton energy of 15 MeV. We thus indicate (p,t two-neutron transfer reactions with very neutron-rich Sn isotopes and at proton energies around 15 MeV as good experimental cases where the surface/volume mixing of the pairing interaction may be probed. In the second part of the manuscript, ground-state to ground-state transitions are investigated. Approximations made to estimate two-nucleon transfer probabilities in ground-state to ground-state transitions and the physical interpretation of these probabilities are discussed. Probabilities are often calculated by approximating both ground states of the initial nucleus A and of the final nucleus A±2 by the same quasiparticle vacuum. We analyze two improvements of this approach. First, the effect of using two different ground states with average numbers of particles A and A±2 is quantified. Second, by using projection techniques, the role of particle number restoration is analyzed. Our analysis

  3. Fluorescence spectral studies on interaction of fluorescent probes with Bovine Serum Albumin (BSA)

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Kaushik, E-mail: ghoshfcy@iitr.ac.in; Rathi, Sweety; Arora, Deepshikha

    2016-07-15

    Interaction of 2-(1-(naphthale-1-ylimino)ethyl)phenol (1), 2-methoxy-4-(((4-methoxyphenyl)imino)methyl)phenol (2) and 2-methoxy-4-((naphthalene-1-ylimino)methyl)phenol (3) with Bovine Serum Albumin (BSA) was examined. Fluorescence spectral data were obtained from the probes by varying the concentration of BSA as well as from BSA by varying the concentration of probes. Synchronous fluorescence measurements were performed and binding constants of the probes were calculated. To understand mode of quenching, Stern–Volmer plot, absorption spectral studies and life time measurements were performed. Förster resonance energy transfer (FRET) was also scrutinized. - Highlights: • Schiff bases with pendant phenolato function and interaction with BSA. • Synchronous fluorescence studies and a preferred interaction with tryptophan. • Probable interaction of probes with Trp-213 residue in the hydrophobic cavity. • 1:1 binding stoichiometry of probes and BSA in Benesi–Hildebrand graph.

  4. Computational procedures for probing interactions in OLS and logistic regression: SPSS and SAS implementations.

    Science.gov (United States)

    Hayes, Andrew F; Matthes, Jörg

    2009-08-01

    Researchers often hypothesize moderated effects, in which the effect of an independent variable on an outcome variable depends on the value of a moderator variable. Such an effect reveals itself statistically as an interaction between the independent and moderator variables in a model of the outcome variable. When an interaction is found, it is important to probe the interaction, for theories and hypotheses often predict not just interaction but a specific pattern of effects of the focal independent variable as a function of the moderator. This article describes the familiar pick-a-point approach and the much less familiar Johnson-Neyman technique for probing interactions in linear models and introduces macros for SPSS and SAS to simplify the computations and facilitate the probing of interactions in ordinary least squares and logistic regression. A script version of the SPSS macro is also available for users who prefer a point-and-click user interface rather than command syntax.

  5. Study of protein-probe complexation equilibria and protein-surfactant interaction using charge transfer fluorescence probe methyl ester of N,N-dimethylamino naphthyl acrylic acid

    Energy Technology Data Exchange (ETDEWEB)

    Mahanta, Subrata; Balia Singh, Rupashree; Bagchi, Arnab [Department of Chemistry University of Calcutta 92, A.P.C. Road, Kolkata 700009 (India); Nath, Debnarayan [Department of Physical Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032 (India); Guchhait, Nikhil, E-mail: nguchhait@yahoo.co [Department of Chemistry University of Calcutta 92, A.P.C. Road, Kolkata 700009 (India)

    2010-06-15

    In this paper, we demonstrate the interaction between intramolecular charge transfer (ICT) probe-Methyl ester of N,N-dimethylamino naphthyl acrylic acid (MDMANA) with bovine serum albumin (BSA) using absorption and fluorescence emission spectroscopy. The nature of probe protein binding interaction, fluorescence resonance energy transfer from protein to probe and time resolved fluorescence decay measurement predict that the probe molecule binds strongly to the hydrophobic cavity of the protein. Furthermore, the interaction of the anionic surfactant sodium dodecyl sulphate (SDS) with water soluble protein BSA has been investigated using MDMANA as fluorescenece probe. The changes in the spectral characteristics of charge transfer fluorescence probe MDMANA in BSA-SDS environment reflects well the nature of the protein-surfactant binding interaction such as specific binding, non-cooperative binding, cooperative binding and saturation binding.

  6. Solute-solvent interactions and dynamics probed by THz light

    Science.gov (United States)

    Schwaab, Gerhard; Böhm, Fabian; Ma, Chun-Yu; Havenith, Martina

    The THz range (1-12 THz, 30-400 cm-1) is especially suited to probe changes in the solvent dynamics induced by solutes of different character (hydrophobic, hydrophilic, charged, neutral). In recent years we have investigated a large variety of such solutes and found characteristic spectral fingerprints for ions, but also for uncharged solutes, such as alcohols. We will present a status report on our current understanding of the observed spectral changes and how they relate to physico-chemical parameters like hydration shell size or the lifetime of an excited intermolecular oscillation. In addition, we will show, that in some cases the spectral changes are closely related to the partition function yielding access to a microscopic understanding of macroscopic thermodynamic functions. The authors gratefully acknowledge financial support from the Cluster of Excellence RESOLV (Ruhr-Universität, EXC1069) funded by the Deutsche Forschungsgemeinschaft.

  7. Probing non nucleonic degrees of freedom with strong and electromagnetic interactions

    International Nuclear Information System (INIS)

    Frois, B.

    1985-10-01

    In this talk, I would like to examine our present view on non-nucleonic degrees of freedom with a few typical experimental results obtained recently both with hadronic and electromagnetic probes at intermediate energies. It is the first generation of experimental data which has probed mesonic degrees of freedom with a spatial resolution of the order of 0.5 fm. This has made possible for example the measurement of the size of the pion-nucleon interaction region. This is very stimulating progress and we begin to have a coherent overview on the various reaction mechanisms which are induced by hadronic and electromagnetic probes

  8. Scanning probe and optical tweezer investigations of biomolecular interactions

    International Nuclear Information System (INIS)

    Rigby-Singleton, Shellie

    2002-01-01

    A complex array of intermolecular forces controls the interactions between and within biological molecules. The desire to empirically explore the fundamental forces has led to the development of several biophysical techniques. Of these, the atomic force microscope (AFM) and the optical tweezers have been employed throughout this thesis to monitor the intermolecular forces involved in biomolecular interactions. The AFM is a well-established force sensing technique capable of measuring biomolecular interactions at a single molecule level. However, its versatility has not been extrapolated to the investigation of a drug-enzyme complex. The energy landscape for the force induced dissociation of the DHFR-methotrexate complex was studied. Revealing an energy barrier to dissociation located ∼0.3 nm from the bound state. Unfortunately, the AFM has a limited range of accessible loading rates and in order to profile the complete energy landscape alternative force sensing instrumentation should be considered, for example the BFP and optical tweezers. Thus, this thesis outlines the development and construction an optical trap capable of measuring intermolecular forces between biomolecules at the single molecule level. To demonstrate the force sensing abilities of the optical set up, proof of principle measurements were performed which investigate the interactions between proteins and polymer surfaces subjected to varying degrees of argon plasma treatment. Complementary data was gained from measurements performed independently by the AFM. Changes in polymer resistance to proteins as a response to changes in polymer surface chemistry were detected utilising both AFM and optical tweezers measurements. Finally, the AFM and optical tweezers were employed as ultrasensitive biosensors. Single molecule investigations of the antibody-antigen interaction between the cardiac troponin I marker and its complementary antibody, reveals the impact therapeutic concentrations of heparin have

  9. Long-range interactions between probes, particles and surfaces

    International Nuclear Information System (INIS)

    Ritchie, R.H.; Manson, J.R.

    1987-01-01

    A brief review is given of some applications of a novel form of self-energy theory. These include the image force experienced by an electron near a metal, the van der Waals interaction between two molecules and the polarization potential of atomic scattering theory

  10. Phthalic Acid Chemical Probes Synthesized for Protein-Protein Interaction Analysis

    Directory of Open Access Journals (Sweden)

    Chin-Jen Wu

    2013-06-01

    Full Text Available Plasticizers are additives that are used to increase the flexibility of plastic during manufacturing. However, in injection molding processes, plasticizers cannot be generated with monomers because they can peel off from the plastics into the surrounding environment, water, or food, or become attached to skin. Among the various plasticizers that are used, 1,2-benzenedicarboxylic acid (phthalic acid is a typical precursor to generate phthalates. In addition, phthalic acid is a metabolite of diethylhexyl phthalate (DEHP. According to Gene_Ontology gene/protein database, phthalates can cause genital diseases, cardiotoxicity, hepatotoxicity, nephrotoxicity, etc. In this study, a silanized linker (3-aminopropyl triethoxyslane, APTES was deposited on silicon dioxides (SiO2 particles and phthalate chemical probes were manufactured from phthalic acid and APTES–SiO2. These probes could be used for detecting proteins that targeted phthalic acid and for protein-protein interactions. The phthalic acid chemical probes we produced were incubated with epithelioid cell lysates of normal rat kidney (NRK-52E cells to detect the interactions between phthalic acid and NRK-52E extracted proteins. These chemical probes interacted with a number of chaperones such as protein disulfide-isomerase A6, heat shock proteins, and Serpin H1. Ingenuity Pathways Analysis (IPA software showed that these chemical probes were a practical technique for protein-protein interaction analysis.

  11. Ion-atom interactions probed by photofragment spectroscopy

    International Nuclear Information System (INIS)

    Helm, H.

    1984-01-01

    Photofragment spectroscopy studies energetic and dynamical properties of molecular states interacting with dissociation continuum. So far, data for eighteen diatomic molecular ions have been gathered by this technique. This paper is a review of these investigations, introduced by a discussion of the experimental methods used. The wealth of information accessible by ion photofragment spectroscopy challenges the experimentalist in the application of innovative techniques and the theoretician for less approximate accounts of the Hamiltonian. (Auth.)

  12. Probing Molecular Insights into Zika Virus–Host Interactions

    Directory of Open Access Journals (Sweden)

    Ina Lee

    2018-05-01

    Full Text Available The recent Zika virus (ZIKV outbreak in the Americas surprised all of us because of its rapid spread and association with neurologic disorders including fetal microcephaly, brain and ocular anomalies, and Guillain–Barré syndrome. In response to this global health crisis, unprecedented and world-wide efforts are taking place to study the ZIKV-related human diseases. Much has been learned about this virus in the areas of epidemiology, genetic diversity, protein structures, and clinical manifestations, such as consequences of ZIKV infection on fetal brain development. However, progress on understanding the molecular mechanism underlying ZIKV-associated neurologic disorders remains elusive. To date, we still lack a good understanding of; (1 what virologic factors are involved in the ZIKV-associated human diseases; (2 which ZIKV protein(s contributes to the enhanced viral pathogenicity; and (3 how do the newly adapted and pandemic ZIKV strains alter their interactions with the host cells leading to neurologic defects? The goal of this review is to explore the molecular insights into the ZIKV–host interactions with an emphasis on host cell receptor usage for viral entry, cell innate immunity to ZIKV, and the ability of ZIKV to subvert antiviral responses and to cause cytopathic effects. We hope this literature review will inspire additional molecular studies focusing on ZIKV–host Interactions.

  13. Probing Molecular Insights into Zika Virus–Host Interactions

    Science.gov (United States)

    Lee, Ina; Li, Ge; Wang, Shusheng; Desprès, Philippe; Zhao, Richard Y.

    2018-01-01

    The recent Zika virus (ZIKV) outbreak in the Americas surprised all of us because of its rapid spread and association with neurologic disorders including fetal microcephaly, brain and ocular anomalies, and Guillain–Barré syndrome. In response to this global health crisis, unprecedented and world-wide efforts are taking place to study the ZIKV-related human diseases. Much has been learned about this virus in the areas of epidemiology, genetic diversity, protein structures, and clinical manifestations, such as consequences of ZIKV infection on fetal brain development. However, progress on understanding the molecular mechanism underlying ZIKV-associated neurologic disorders remains elusive. To date, we still lack a good understanding of; (1) what virologic factors are involved in the ZIKV-associated human diseases; (2) which ZIKV protein(s) contributes to the enhanced viral pathogenicity; and (3) how do the newly adapted and pandemic ZIKV strains alter their interactions with the host cells leading to neurologic defects? The goal of this review is to explore the molecular insights into the ZIKV–host interactions with an emphasis on host cell receptor usage for viral entry, cell innate immunity to ZIKV, and the ability of ZIKV to subvert antiviral responses and to cause cytopathic effects. We hope this literature review will inspire additional molecular studies focusing on ZIKV–host Interactions. PMID:29724036

  14. The interaction of fluorescent nanodiamond probes with cellular media.

    Science.gov (United States)

    Hemelaar, Simon R; Nagl, Andreas; Bigot, François; Rodríguez-García, Melissa M; de Vries, Marcel P; Chipaux, Mayeul; Schirhagl, Romana

    2017-01-01

    Fluorescent nanodiamonds (FNDs) are promising tools to image cells, bioanalytes and physical quantities such as temperature, pressure, and electric or magnetic fields with nanometer resolution. To exploit their potential for intracellular applications, the FNDs have to be brought into contact with cell culture media. The interactions between the medium and the diamonds crucially influence sensitivity as well as the ability to enter cells. The authors demonstrate that certain proteins and salts spontaneously adhere to the FNDs and may cause aggregation. This is a first investigation on the fundamental questions on how (a) FNDs interact with the medium, and (b) which proteins and salts are being attracted. A differentiation between strongly binding and weakly binding proteins is made. Not all proteins participate in the formation of FND aggregates. Surprisingly, some main components in the medium seem to play no role in aggregation. Simple strategies to prevent aggregation are discussed. These include adding the proteins, which are naturally present in the cell culture to the diamonds first and then inserting them in the full medium. Graphical abstractSchematic of the interaction of nanodiamonds with cell culture medium. Certain proteins and salts adhere to the diamond surface and lead to aggregation or to formation of a protein corona.

  15. The interactions of the HELIOS probe with the solar wind plasma

    International Nuclear Information System (INIS)

    Voigt, G.H.; Isensee, U.; Maassberg, H.

    1981-08-01

    HELIOS solar probe disturbs the solar wind plasma in the near vicinity. Around the probe, a space charge cloud is formed due to strong photoelectron emission and fade out of solar wind particles. The conducting and isolating parts of the surface are differently charged. These effects result in a very complex potential structure in the vicinity of the probe and on the surface. The interactions of the HELIOS probe with the solar wind plasma are described by models based on kinetic theory of plasma. The combination of these models yields an entire and consistent representation of the spacecraft charging and the potential structure. Electron spectra measured by plasma experiment E1 are analysed and compared with results of the theoretical models. (orig.) [de

  16. Probing cocaine-antibody interactions in buffer and human serum.

    Directory of Open Access Journals (Sweden)

    Muthu Ramakrishnan

    Full Text Available Despite progress in cocaine immunotherapy, the kinetic and thermodynamic properties of antibodies which bind to cocaine and its metabolites are not well understood. It is also not clear how the interactions between them differ in a complex matrix such as the serum present in the human body. In the present study, we have used microscale thermophoresis (MST, isothermal titration calorimetry (ITC, and surface plasmon resonance (SPR we have evaluated the affinity properties of a representative mouse monoclonal (mAb08 as well as those of polyclonal antibodies purified from vaccinated mouse and human patient serum.MST analysis of fluorescently tagged mAb08 binding to cocaine reveals an approximately 15 fold decrease in its equilibrium dissociation constant in 20-50% human serum compared with that in saline buffer. A similar trend was also found using enriched polyclonal antibodies purified from vaccinated mice and patient serum, for which we have used fluorescently tagged bovine serum albumin conjugated to succinyl norcocaine (BSA-SNC. This conjugate closely mimics both cocaine and the hapten used to raise these antibodies. The ITC data also revealed that cocaine has a moderate affinity of about 2 µM to 20% human serum and very little interaction with human serum albumin or nonspecific human IgG at that concentration range. In a SPR inhibition experiment, the binding of mAb08 to immobilized BSA-SNC was inhibited by cocaine and benzoylecgonine in a highly competitive manner, whereas the purified polyclonal antibodies from vaccinated humans and mice, revealed preferential selectivity to pharmacologically active cocaine but not to the inactive metabolite benzoylecgonine. We have also developed a simple binding model to simulate the challenges associated with cocaine immunotherapy using the variable quantitative and kinetic properties of the antibodies.High sensitivity calorimetric determination of antibody binding to cocaine and its metabolites provide

  17. Language, interactivity and solution probing: repetition without repetition

    DEFF Research Database (Denmark)

    Cowley, Stephen; Nash, Luarina

    2013-01-01

    Recognition of the importance of autopoiesis to biological systems was crucial in building an alternative to the classic view of cognitive science. However, concepts like structural coupling and autonomy are not strong enough to throw light on language and human problem solving. The argument...... is presented though a case study where a person solves a problem and, in so doing relies on non-local aspects of the ecology as well as his observer's mental domain. Like Anthony Chemero we make links with ecological psychology to emphasize how embodiment draws on cultural resources as people concert thinking......, action and perception. We trace this to human interactivity or sense-saturated coordination that renders possible language and human forms of cognition: it links human sense-making to historical experience. People play roles with natural and cultural artifacts as they act, animate groups and live through...

  18. Probing protein-lipid interactions by FRET between membrane fluorophores

    Science.gov (United States)

    Trusova, Valeriya M.; Gorbenko, Galyna P.; Deligeorgiev, Todor; Gadjev, Nikolai

    2016-09-01

    Förster resonance energy transfer (FRET) is a powerful fluorescence technique that has found numerous applications in medicine and biology. One area where FRET proved to be especially informative involves the intermolecular interactions in biological membranes. The present study was focused on developing and verifying a Monte-Carlo approach to analyzing the results of FRET between the membrane-bound fluorophores. This approach was employed to quantify FRET from benzanthrone dye ABM to squaraine dye SQ-1 in the model protein-lipid system containing a polycationic globular protein lysozyme and negatively charged lipid vesicles composed of phosphatidylcholine and phosphatidylglycerol. It was found that acceptor redistribution between the lipid bilayer and protein binding sites resulted in the decrease of FRET efficiency. Quantification of this effect in terms of the proposed methodology yielded both structural and binding parameters of lysozyme-lipid complexes.

  19. Probing skin interaction with hydrogen peroxide using diffuse reflectance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Zonios, George [Department of Materials Science and Engineering, University of Ioannina, 45110 Ioannina (Greece); Dimou, Aikaterini [Department of Materials Science and Engineering, University of Ioannina, 45110 Ioannina (Greece); Galaris, Dimitrios [Laboratory of Biological Chemistry, School of Medicine, University of Ioannina, 45110 Ioannina (Greece)

    2008-01-07

    Hydrogen peroxide is an important oxidizing agent in biological systems. In dermatology, it is frequently used as topical antiseptic, it has a haemostatic function, it can cause skin blanching, and it can facilitate skin tanning. In this work, we investigated skin interaction with hydrogen peroxide, non-invasively, using diffuse reflectance spectroscopy. We observed transient changes in the oxyhaemoglobin and deoxyhaemoglobin concentrations as a result of topical application of dilute H{sub 2}O{sub 2} solutions to the skin, with changes in deoxyhaemoglobin concentration being more pronounced. Furthermore, we did not observe any appreciable changes in melanin absorption properties as well as in the skin scattering properties. We also found no evidence for production of oxidized haemoglobin forms. Our observations are consistent with an at least partial decomposition of hydrogen peroxide within the stratum corneum and epidermis, with the resulting oxygen and/or remaining hydrogen peroxide inducing vasoconstriction to dermal blood vessels and increasing haemoglobin oxygen saturation. An assessment of the effects of topical application of hydrogen peroxide to the skin may serve as the basis for the development of non-invasive techniques to measure skin antioxidant capacity and also may shed light onto skin related disorders such as vitiligo.

  20. Probing skin interaction with hydrogen peroxide using diffuse reflectance spectroscopy

    International Nuclear Information System (INIS)

    Zonios, George; Dimou, Aikaterini; Galaris, Dimitrios

    2008-01-01

    Hydrogen peroxide is an important oxidizing agent in biological systems. In dermatology, it is frequently used as topical antiseptic, it has a haemostatic function, it can cause skin blanching, and it can facilitate skin tanning. In this work, we investigated skin interaction with hydrogen peroxide, non-invasively, using diffuse reflectance spectroscopy. We observed transient changes in the oxyhaemoglobin and deoxyhaemoglobin concentrations as a result of topical application of dilute H 2 O 2 solutions to the skin, with changes in deoxyhaemoglobin concentration being more pronounced. Furthermore, we did not observe any appreciable changes in melanin absorption properties as well as in the skin scattering properties. We also found no evidence for production of oxidized haemoglobin forms. Our observations are consistent with an at least partial decomposition of hydrogen peroxide within the stratum corneum and epidermis, with the resulting oxygen and/or remaining hydrogen peroxide inducing vasoconstriction to dermal blood vessels and increasing haemoglobin oxygen saturation. An assessment of the effects of topical application of hydrogen peroxide to the skin may serve as the basis for the development of non-invasive techniques to measure skin antioxidant capacity and also may shed light onto skin related disorders such as vitiligo

  1. Probing many-body interactions in an optical lattice clock

    Energy Technology Data Exchange (ETDEWEB)

    Rey, A.M., E-mail: arey@jilau1.colorado.edu [JILA, NIST and University of Colorado, Department of Physics, Boulder, CO 80309 (United States); Gorshkov, A.V. [Joint Quantum Institute, NIST and University of Maryland, Department of Physics, College Park, MD 20742 (United States); Kraus, C.V. [Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, A-6020 Innsbruck (Austria); Institute for Theoretical Physics, University of Innsbruck, A-6020 Innsbruck (Austria); Martin, M.J. [JILA, NIST and University of Colorado, Department of Physics, Boulder, CO 80309 (United States); Institute for Quantum Information and Matter, California Institute of Technology, Pasadena, CA 91125 (United States); Bishof, M.; Swallows, M.D.; Zhang, X.; Benko, C.; Ye, J. [JILA, NIST and University of Colorado, Department of Physics, Boulder, CO 80309 (United States); Lemke, N.D.; Ludlow, A.D. [National Institute of Standards and Technology, Boulder, CO 80305 (United States)

    2014-01-15

    We present a unifying theoretical framework that describes recently observed many-body effects during the interrogation of an optical lattice clock operated with thousands of fermionic alkaline earth atoms. The framework is based on a many-body master equation that accounts for the interplay between elastic and inelastic p-wave and s-wave interactions, finite temperature effects and excitation inhomogeneity during the quantum dynamics of the interrogated atoms. Solutions of the master equation in different parameter regimes are presented and compared. It is shown that a general solution can be obtained by using the so called Truncated Wigner Approximation which is applied in our case in the context of an open quantum system. We use the developed framework to model the density shift and decay of the fringes observed during Ramsey spectroscopy in the JILA {sup 87}Sr and NIST {sup 171}Yb optical lattice clocks. The developed framework opens a suitable path for dealing with a variety of strongly-correlated and driven open-quantum spin systems. -- Highlights: •Derived a theoretical framework that describes many-body effects in a lattice clock. •Validated the analysis with recent experimental measurements. •Demonstrated the importance of beyond mean field corrections in the dynamics.

  2. Probing non-standard interactions at Daya Bay

    Energy Technology Data Exchange (ETDEWEB)

    Agarwalla, Sanjib Kumar; Bagchi, Partha [Institute of Physics, Sachivalaya Marg,Sainik School Post, Bhubaneswar 751005 (India); Forero, David V. [AHEP Group, Institut de Física Corpuscular - C.S.I.C./Universitat de València,Parc Cientific de Paterna, C/ Catedratico José Beltrán, 2 E-46980 Paterna (València) (Spain); Center for Neutrino Physics, Virginia Tech,Blacksburg, VA 24061 (United States); Tórtola, Mariam [AHEP Group, Institut de Física Corpuscular - C.S.I.C./Universitat de València,Parc Cientific de Paterna, C/ Catedratico José Beltrán, 2 E-46980 Paterna (València) (Spain)

    2015-07-13

    In this article we consider the presence of neutrino non-standard interactions (NSI) in the production and detection processes of reactor antineutrinos at the Daya Bay experiment. We report for the first time, the new constraints on the flavor non-universal and flavor universal charged-current NSI parameters, estimated using the currently released 621 days of Daya Bay data. New limits are placed assuming that the new physics effects are just inverse of each other in the production and detection processes. With this special choice of the NSI parameters, we observe a shift in the oscillation amplitude without distorting the L/E pattern of the oscillation probability. This shift in the depth of the oscillation dip can be caused by the NSI parameters as well as by θ{sub 13}, making it quite difficult to disentangle the NSI effects from the standard oscillations. We explore the correlations between the NSI parameters and θ{sub 13} that may lead to significant deviations in the reported value of the reactor mixing angle with the help of iso-probability surface plots. Finally, we present the limits on electron, muon/tau, and flavor universal (FU) NSI couplings with and without considering the uncertainty in the normalization of the total event rates. Assuming a perfect knowledge of the event rates normalization, we find strong upper bounds ∼ 0.1% for the electron and FU cases improving the present limits by one order of magnitude. However, for a conservative error of 5% in the total normalization, these constraints are relaxed by almost one order of magnitude.

  3. Probing non-standard interactions at Daya Bay

    International Nuclear Information System (INIS)

    Agarwalla, Sanjib Kumar; Bagchi, Partha; Forero, David V.; Tórtola, Mariam

    2015-01-01

    In this article we consider the presence of neutrino non-standard interactions (NSI) in the production and detection processes of reactor antineutrinos at the Daya Bay experiment. We report for the first time, the new constraints on the flavor non-universal and flavor universal charged-current NSI parameters, estimated using the currently released 621 days of Daya Bay data. New limits are placed assuming that the new physics effects are just inverse of each other in the production and detection processes. With this special choice of the NSI parameters, we observe a shift in the oscillation amplitude without distorting the L/E pattern of the oscillation probability. This shift in the depth of the oscillation dip can be caused by the NSI parameters as well as by θ 13 , making it quite difficult to disentangle the NSI effects from the standard oscillations. We explore the correlations between the NSI parameters and θ 13 that may lead to significant deviations in the reported value of the reactor mixing angle with the help of iso-probability surface plots. Finally, we present the limits on electron, muon/tau, and flavor universal (FU) NSI couplings with and without considering the uncertainty in the normalization of the total event rates. Assuming a perfect knowledge of the event rates normalization, we find strong upper bounds ∼ 0.1% for the electron and FU cases improving the present limits by one order of magnitude. However, for a conservative error of 5% in the total normalization, these constraints are relaxed by almost one order of magnitude.

  4. Unnatural amino acids as probes of ligand-receptor interactions and their conformational consequences

    DEFF Research Database (Denmark)

    Pless, Stephan Alexander; Ahern, Christopher A

    2013-01-01

    -edge synthetic and chemical biological approaches. Here we summarize recent advances in the use of site-directed incorporation of unnatural amino acids and chemical probes to study ligand-receptor interactions, determine the location of binding sites, and examine the downstream conformational consequences...

  5. Environmentally sensitive probes for monitoring protein-membrane interactions at nanomolar concentrations

    Czech Academy of Sciences Publication Activity Database

    Shvadchak, Volodymyr V.; Kucherak, Oleksandr; Afitska, Kseniia; Dziuba, D.; Yushchenko, Dmytro A.

    2017-01-01

    Roč. 1859, č. 5 (2017), s. 852-859 ISSN 0005-2736 Institutional support: RVO:61388963 Keywords : solvatochromic probes * fluorescence * protein-membrane interaction * affinity * binding stoichiometry * alpha-synuclein Subject RIV: CE - Biochemistry OBOR OECD: Biochemistry and molecular biology Impact factor: 3.498, year: 2016

  6. Residue-specific annotation of disorder-to-order transition and cathepsin inhibition of a propeptide-like crammer from D. melanogaster.

    Directory of Open Access Journals (Sweden)

    Tien-Sheng Tseng

    Full Text Available Drosophila melanogaster crammer is a novel cathepsin inhibitor involved in long-term memory formation. A molten globule-to-ordered structure transition is required for cathepsin inhibition. This study reports the use of alanine scanning to probe the critical residues in the two hydrophobic cores and the salt bridges of crammer in the context of disorder-to-order transition and cathepsin inhibition. Alanine substitution of the aromatic residues W9, Y12, F16, Y20, Y32, and W53 within the hydrophobic cores, and charged residues E8, R28, R29, and E67 in the salt bridges considerably decrease the ability of crammer to inhibit Drosophila cathepsin B (CTSB. Far-UV circular dichroism (CD, intrinsic fluorescence, and nuclear magnetic resonance (NMR spectroscopies show that removing most of the aromatic and charged side-chains substantially reduces thermostability, alters pH-dependent helix formation, and disrupts the molten globule-to-ordered structure transition. Molecular modeling indicates that W53 in the hydrophobic Core 2 is essential for the interaction between crammer and the prosegment binding loop (PBL of CTSB; the salt bridge between R28 and E67 is critical for the appropriate alignment of the α-helix 4 toward the CTSB active cleft. The results of this study show detailed residue-specific dissection of folding transition and functional contributions of the hydrophobic cores and salt bridges in crammer, which have hitherto not been characterized for cathepsin inhibition by propeptide-like cysteine protease inhibitors. Because of the involvements of cathepsin inhibitors in neurodegenerative diseases, these structural insights can serve as a template for further development of therapeutic inhibitors against human cathepsins.

  7. Probing of the interfacial Heisenberg and Dzyaloshinskii-Moriya exchange interaction by magnon spectroscopy.

    Science.gov (United States)

    Zakeri, Khalil

    2017-01-11

    This Topical Review presents an overview of the recent experimental results on the quantitative determination of the magnetic exchange parameters in ultrathin magnetic films and multilayers grown on different substrates. The experimental approaches for probing both the symmetric Heisenberg and the antisymmetric Dzyaloshinskii-Moriya exchange interaction in ultrathin magnetic films and at interfaces are discussed in detail. It is explained how the experimental spectrum of magnetic excitations can be used to quantify the strength of these interactions.

  8. Probing in-medium spin–orbit interaction with intermediate-energy heavy-ion collisions

    International Nuclear Information System (INIS)

    Xu, Jun; Li, Bao-An

    2013-01-01

    Incorporating for the first time both the spin and isospin degrees of freedom explicitly in transport model simulations of intermediate-energy heavy-ion collisions, we observe that a local spin polarization appears during collision process. Most interestingly, it is found that the nucleon spin up–down differential transverse flow is a sensitive probe of the spin–orbit interaction, providing a novel approach to probe both the density and isospin dependence of the in-medium spin–orbit coupling that is important for understanding the structure of rare isotopes and synthesis of superheavy elements

  9. Final report: Mapping Interactions in Hybrid Systems with Active Scanning Probes

    Energy Technology Data Exchange (ETDEWEB)

    Berezovsky, Jesse [Case Western Reserve Univ., Cleveland, OH (United States)

    2017-09-29

    This project aimed to study and map interactions between components of hybrid nanodevices using a novel scanning probe approach. To enable this work, we initially constructed a flexible experimental apparatus allowing for simultaneous scanning probe and confocal optical microscopy measurements. This setup was first used for all-optical measurements of nanostructures, with the focus then shifting to hybrid devices in which single coherent electron spins are coupled to micron-scale ferromagnetic elements, which may prove useful for addressing single spins, enhanced sensing, or spin-wave-mediated coupling of spins for quantum information applications. A significant breakthrough was the realization that it is not necessary to fabricate a magnetic structure on a scanning probe – instead a ferromagnetic vortex core can act as an integrated, solid state, scanning probe. The core of the vortex produces a very strong, localized fringe field which can be used analogously to an MFM tip. Unlike a traditional MFM tip, however, the vortex core is scanned within an integrated device (eliminating drift), and can be moved on vastly faster timescales. This approach allows the detailed investigation of interactions between single spins and complex driven ferromagnetic dynamics.

  10. Probing interaction and spatial curvature in the holographic dark energy model

    International Nuclear Information System (INIS)

    Li, Miao; Li, Xiao-Dong; Wang, Shuang; Wang, Yi; Zhang, Xin

    2009-01-01

    In this paper we place observational constraints on the interaction and spatial curvature in the holographic dark energy model. We consider three kinds of phenomenological interactions between holographic dark energy and matter, i.e., the interaction term Q is proportional to the energy densities of dark energy (ρ Λ ), matter (ρ m ), and matter plus dark energy (ρ m +ρ Λ ). For probing the interaction and spatial curvature in the holographic dark energy model, we use the latest observational data including the type Ia supernovae (SNIa) Constitution data, the shift parameter of the cosmic microwave background (CMB) given by the five-year Wilkinson Microwave Anisotropy Probe (WMAP5) observations, and the baryon acoustic oscillation (BAO) measurement from the Sloan Digital Sky Survey (SDSS). Our results show that the interaction and spatial curvature in the holographic dark energy model are both rather small. Besides, it is interesting to find that there exists significant degeneracy between the phenomenological interaction and the spatial curvature in the holographic dark energy model

  11. Probing Enzyme-Surface Interactions via Protein Engineering and Single-Molecule Techniques

    Science.gov (United States)

    2017-06-26

    SECURITY CLASSIFICATION OF: The overall objective of this research was to exploit protein engineering and fluorescence single-molecule methods to...enhance our understanding of the interaction of proteins and surfaces. Given this objective, the specific aims of this research were to: 1) exploit the...incorporation of unnatural amino acids in proteins to introduce single-molecule probes (i.e., fluorophores for fluorescence resonance energy transfer

  12. Probing the interactions of mitoxantrone with biomimetic membranes with electrochemical and spectroscopic techniques

    International Nuclear Information System (INIS)

    Nieciecka, Dorota; Królikowska, Agata; Krysinski, Paweł

    2015-01-01

    Graphical abstract: Display Omitted - Abstract: Mitoxantrone – an anticancer drug – was used to probe the interactions of this class of cytostatic molecules with biomimetic monolayers. The drug effect was monitored with electrochemical (cyclic voltammetry and electrochemical impedance spectroscopy), as well as spectroscopic techniques (surface enhanced Raman scattering), during its passive partitioning/penetration through the mixed Langmuir and Langmuir–Blodgett monolayers after their transfer on gold electrodes. This approach allowed us to discriminate between the drug interactions with hydrophilic head-group region and hydrophobic alkyl chains moiety of such monolayers

  13. Investigation of ferromagnetic spinel semiconductors by hyperfine interactions of implanted nuclear probes

    CERN Document Server

    Samokhvalov, V; Dietrich, M; Schneider, F; Tiginyanu, I M; Tsurkan, V; Unterricker, S

    2003-01-01

    The semiconducting ferromagnetic spinel compounds CdCr//2Se //4, CdCr //2S//4, HgCr//2Se//4 and CuCr//2Se//4 (metallic) were investigated by the perturbed angular correlations (PAC) method with the radioactive probes **1**1**1In, **1**1**1**mCd, **1**1**1Ag, **1**1**7Cd, **1**9**9**mHg and **7**7Br. The probes were implanted at the ISOLDE on-line separator (CERN-Geneva) into single crystals. From the time dependence of the PAC spectra and the measured hyperfine interaction parameters: electric field gradient and magnetic hyperfine field, the probe positions and the thermal behavior of the probes could be determined. Cd, Ag and Hg are substituted at the A-site, In at the A- and B-site in the semiconducting compounds and Br at the anion position. Electric and magnetic hyperfine fields were used as test quantities for theoretical charge and spin density distributions of LAPW calculations (WIEN97).

  14. AFM Colloidal Probe Measurements Implicate Capillary Condensation in Punch-Particle Surface Interactions during Tableting.

    Science.gov (United States)

    Badal Tejedor, Maria; Nordgren, Niklas; Schuleit, Michael; Millqvist-Fureby, Anna; Rutland, Mark W

    2017-11-21

    Adhesion of the powders to the punches is a common issue during tableting. This phenomenon is known as sticking and affects the quality of the manufactured tablets. Defective tablets increase the cost of the manufacturing process. Thus, the ability to predict the tableting performance of the formulation blend before the process is scaled-up is important. The adhesive propensity of the powder to the tableting tools is mostly governed by the surface-surface adhesive interactions. Atomic force microscopy (AFM) colloidal probe is a surface characterization technique that allows the measurement of the adhesive interactions between two materials of interest. In this study, AFM steel colloidal probe measurements were performed on ibuprofen, MCC (microcrystalline cellulose), α-lactose monohydrate, and spray-dried lactose particles as an approach to modeling the punch-particle surface interactions during tableting. The excipients (lactose and MCC) showed constant, small, attractive, and adhesive forces toward the steel surface after a repeated number of contacts. In comparison, ibuprofen displayed a much larger attractive and adhesive interaction increasing over time both in magnitude and in jump-in/jump-out separation distance. The type of interaction acting on the excipient-steel interface can be related to a van der Waals force, which is relatively weak and short-ranged. By contrast, the ibuprofen-steel interaction is described by a capillary force profile. Even though ibuprofen is not highly hydrophilic, the relatively smooth surfaces of the crystals allow "contact flooding" upon contact with the steel probe. Capillary forces increase because of the "harvesting" of moisture-due to the fast condensation kinetics-leaving a residual condensate that contributes to increase the interaction force after each consecutive contact. Local asperity contacts on the more hydrophilic surface of the excipients prevent the flooding of the contact zone, and there is no such adhesive

  15. Atomic wavefunctions probed through strong-field light-matter interaction

    Energy Technology Data Exchange (ETDEWEB)

    Mairesse, Y; Villeneuve, D M; Corkum, P B; Dudovich, N [Natl Res Council Canada, Ottawa, ON K1A 0R6 (Canada); Shafir, D; Dudovich, N [Weizmann Inst Sci, Dept Phys Complex Syst, IL-76100 Rehovot, (Israel); Mairesse, Y [Univ Bordeaux 1, CELIA, CNRS, UMR 5107, CEA, F-33405 Talence (France)

    2009-07-01

    Strong-field light-matter interactions can encode the spatial properties of the electronic wavefunctions that contribute to the process. In particular, the broadband harmonic spectra, measured for a series of molecular alignments, can be used to create a tomographic reconstruction of molecular orbitals. Here, we present an extension of the tomography approach to systems that cannot be naturally aligned. We demonstrate this ability by probing the two-dimensional properties of atomic wavefunctions. By manipulating an electron-ion re-collision process, we are able to resolve the symmetry of the atomic wavefunction with high contrast. (authors)

  16. Characterisation of target plasma required for REB-plasma interaction studies using cylindrical Langmuir probes

    International Nuclear Information System (INIS)

    Roychowdhury, P.; Paithankar, A.S.; Iyyengar, S.K.; Rohatgi, V.K.

    1987-01-01

    The target plasma required for relativistic electron beam (REB)-plasma interaction studies has been generated by coaxial plasma gun. The measurement of electron density and temperature has been carried out using cylindrical Langmuir probes. Probes both oriented parallel and transverse to the flow have been used. The spatial as well as temporal variation of electron density and temperature have been studied. The typical electron density and temperature measured by probe were in the range of 9.0-3.5 x 10 13 cm -3 and 5-7 eV respectively. The typical e-folding decay time of density was 6.2 μs, while no appreciable change in electron temperature was observed until 10 μs after the peak density. The density decays by about 50% at distance of 30 cm from the gun. The plasma flow velocity has been measured by the time of flight technique and was found to be 2.5 x 10 6 cm s -1 . The plasma radius measured by dosimeter film, at distance of 30 cm from the gun was 3 cm. (author)

  17. Probe manipulators for Wendelstein 7-X and their interaction with the magnetic topology

    Science.gov (United States)

    M, RACK; D, HÖSCHEN; D, REITER; B, UNTERBERG; J, W. COENEN; S, BREZINSEK; O, NEUBAUER; S, BOZHENKOV; G, CZYMEK; Y, LIANG; M, HUBENY; Ch, LINSMEIER; the Wendelstein 7-X Team

    2018-05-01

    Probe manipulators are a versatile addition to typical plasma edge diagnostics. Equipped with material samples they allow for detailed investigation of plasma–wall interaction processes, such as material erosion, deposition or impurity transport pathways. When combined with electrical probes, a study of scrape-off layer and plasma edge density, temperature and flow profiles as well as magnetic topologies is possible. A mid-plane manipulator is already in operation on Wendelstein 7-X. A system in the divertor region is currently under development. In the present paper we discuss the critical issue of heat and power loads, power redistribution and experimental access to the complex magnetic topology of Wendelstein 7-X. All the aforementioned aspects are of relevance for the design and operation of a probe manipulator in a device like Wendelstein 7-X. A focus is put on the topological region that is accessible for the different coil current configurations at Wendelstein 7-X and the power load on the manipulator with respect to the resulting different magnetic configurations. Qualitative analysis of power loads on plasma-facing components is performed using a numerical tracer particle diffusion tool provided via the Wendelstein 7-X Webservices.

  18. Study of plasma-material surface interaction using Langmuir probe technique during plasma treatment

    International Nuclear Information System (INIS)

    Saloum, S.; Akel, M.

    2009-06-01

    In this study, we tried to understand the plasma-surface interactions by using Langmuir probes. Two different types of plasmas were studied, the first is the electropositive plasma in Argon and the second is the electronegative plasma in Sulfur Hexafluoride. In the first type, the effects of Argon gas pressure, the injection of Helium in the remote zone and the substrate bias on the measurements of the Electron Energy Probability Function (EEPF) and on the plasma parameters (electron density (n e ), effective electron temperature (T e ff), plasma potential (V p ) and floating potential (V f )) have been investigated. The obtained EEPFs and plasma parameters have been used to control two remote plasma processes. The first is the remote Plasma Enhanced Chemical Vapor Deposition (PE-CVD) of thin films, on silicon wafers, from Hexamethyldisoloxane (HMDSO) precursor diluted in the remote Ar-He plasma. The second is the pure Argon remote plasma treatment of polymethylmethacrylate (PMMA) polymer surface. In the second type, the plasma diagnostics were performed in the remote zone as a function of SF 6 flow rate, where relative concentrations of fluorine atoms were measured using actinometry optical emission spectroscopy; electron density, electron temperature and plasma potential were determined using single cylindrical Langmuir probe, positive ion flux and negative ion fraction were determined using an planar probe. The silicon etching process in SF 6 plasma was studied. (author)

  19. Pyrethroid Activity-Based Probes for Profiling Cytochrome P450 Activities Associated with Insecticide Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Ismail, Hanafy M.; O' Neill, Paul M.; Hong, David; Finn, Robert; Henderson, Colin; Wright, Aaron T.; Cravatt, Benjamin; Hemingway, Janet; Paine, Mark J.

    2014-01-18

    Pyrethroid insecticides are used to control a diverse spectrum of diseases spread by arthropods. We have developed a suite of pyrethroid mimetic activity based probes (PyABPs) to selectively label and identify P450s associated with pyrethroid metabolism. The probes were screened against pyrethroid metabolizing and non-metabolizing mosquito P450s, as well as rodent microsomes to measure labeling specificity, plus CPR and b5 knockout mouse livers to validate P450 activation and establish the role for b5 in probe activation. Using a deltamethrin mimetic PyABP we were able to profile active enzymes in rat liver microsomes and identify pyrethroid metabolizing enzymes in the target tissue. The most reactive enzyme was a P450, CYP2C11, which is known to metabolize deltamethrin. Furthermore, several other pyrethroid metabolizers were identified (CYPs 2C6, 3A4, 2C13 and 2D1) along with related detoxification enzymes, notably UDP-g’s 2B1 - 5, suggesting a network of associated pyrethroid metabolizing enzymes, or ‘pyrethrome’. Considering the central role that P450s play in metabolizing insecticides, we anticipate that PyABPs will aid the identification and profiling of P450s associated with insecticide pharmacology in a wide range of species, improving understanding of P450-insecticide interactions and aiding the development of new tools for disease control.

  20. Study of plasma-material surface interaction using langmuir probe technique during plasma treatment

    International Nuclear Information System (INIS)

    Saloum, S.; Akel, M.

    2012-01-01

    In this study, we tried to understand the plasma-surface interactions by using Langmuir probes. Two different types of plasmas were studied, the first is the electropositive plasma in Argon and the second is the electronegative plasma in Sulfur Hexafluoride. In the first type, the effects of Argon gas pressure, the injection of Helium in the remote zone and the substrate bias on the measurements of the Electron Energy Probability Function (EEPF) and on the plasma parameters (electron density (n e ), effective electron temperature (T e ff), plasma potential (V p ) and floating potential (V f )) have been investigated. The obtained EEPFs and plasma parameters have been used to control two remote plasma processes. The first is the remote Plasma Enhanced Chemical Vapor Deposition (PE-CVD) of thin films, on silicon wafers, from Hexamethyldisiloxane (HMDSO) precursor diluted in the remote Ar-He plasma. The second is the pure Argon remote plasma treatment of polymethylmethacrylate (PMMA) polymer surface. In the second type, the plasma diagnostics were performed in the remote zone as a function of SF 6 flow rate, where relative concentrations of fluorine atoms were measured using actinometry optical emission spectroscopy; electron density, electron temperature and plasma potential were determined using single cylindrical Langmuir probe, positive ion flux and negative ion fraction were determined using an planar probe. The silicon etching process in SF 6 plasma was studied. (author)

  1. Pyrethroid activity-based probes for profiling cytochrome P450 activities associated with insecticide interactions.

    Science.gov (United States)

    Ismail, Hanafy M; O'Neill, Paul M; Hong, David W; Finn, Robert D; Henderson, Colin J; Wright, Aaron T; Cravatt, Benjamin F; Hemingway, Janet; Paine, Mark J I

    2013-12-03

    Pyrethroid insecticides are used to control diseases spread by arthropods. We have developed a suite of pyrethroid mimetic activity-based probes (PyABPs) to selectively label and identify P450s associated with pyrethroid metabolism. The probes were screened against pyrethroid-metabolizing and nonmetabolizing mosquito P450s, as well as rodent microsomes, to measure labeling specificity, plus cytochrome P450 oxidoreductase and b5 knockout mouse livers to validate P450 activation and establish the role for b5 in probe activation. Using PyABPs, we were able to profile active enzymes in rat liver microsomes and identify pyrethroid-metabolizing enzymes in the target tissue. These included P450s as well as related detoxification enzymes, notably UDP-glucuronosyltransferases, suggesting a network of associated pyrethroid-metabolizing enzymes, or "pyrethrome." Considering the central role P450s play in metabolizing insecticides, we anticipate that PyABPs will aid in the identification and profiling of P450s associated with insecticide pharmacology in a wide range of species, improving understanding of P450-insecticide interactions and aiding the development of unique tools for disease control.

  2. Probing the Odderon in coherent hadron–hadron interactions at CERN LHC

    Energy Technology Data Exchange (ETDEWEB)

    Gonçalves, V.P., E-mail: barros@ufpel.edu.br [High and Medium Energy Group, Instituto de Física e Matemática, Universidade Federal de Pelotas, Caixa Postal 354, CEP 96010-900, Pelotas, RS (Brazil)

    2013-03-15

    One of the open questions of the strong interaction theory is the existence of the Odderon, which is an unambiguous prediction of Quantum Chromodynamics, but still not confirmed in the experiment. In this paper we propose the study of the diffractive η{sub c} photoproduction in coherent interactions as a new alternative to probe the Odderon in pp and PbPb collisions at CERN LHC. As the Pomeron exchange cannot contribute to this process, its observation would indicate the existence of the Odderon. We predict total cross sections of order of pb(μb) for pp (PbPb) collisions and large values for the event rates/year, which makes, in principle, the experimental analysis of this process feasible at LHC.

  3. Assignment of methyl NMR resonances of a 52 kDa protein with residue-specific 4D correlation maps

    International Nuclear Information System (INIS)

    Mishra, Subrata H.; Frueh, Dominique P.

    2015-01-01

    Methyl groups have become key probes for structural and functional studies by nuclear magnetic resonance. However, their NMR signals cluster in a small spectral region and assigning their resonances can be a tedious process. Here, we present a method that facilitates assignment of methyl resonances from assigned amide groups. Calculating the covariance between sensitive methyl and amide 3D spectra, each providing correlations to C α and C β separately, produces 4D correlation maps directly correlating methyl groups to amide groups. Optimal correlation maps are obtained by extracting residue-specific regions, applying derivative to the dimensions subject to covariance, and multiplying 4D maps stemming from different 3D spectra. The latter procedure rescues weak signals that may be missed in traditional assignment procedures. Using these covariance correlation maps, nearly all assigned isoleucine, leucine, and valine amide resonances of a 52 kDa nonribosomal peptide synthetase cyclization domain were paired with their corresponding methyl groups

  4. Role of polarization in probing anomalous gauge interactions of the Higgs boson

    International Nuclear Information System (INIS)

    Biswal, Sudhansu S.; Godbole, Rohini M.; Choudhury, Debajyoti; Mamta

    2009-01-01

    We explore the use of polarized e + /e - beams and/or the information on final state decay lepton polarizations in probing the interaction of the Higgs boson with a pair of vector bosons. A model independent analysis of the process e + e - →ffH, where f is any light fermion, is carried out through the construction of observables having identical properties under the discrete symmetry transformations as different individual anomalous interactions. This allows us to probe an individual anomalous term independent of the others. We find that initial state beam polarization can significantly improve the sensitivity to CP-odd couplings of the Z boson with the Higgs boson (ZZH). Moreover, an ability to isolate events with a particular τ helicity, with even 40% efficiency, can improve sensitivities to certain ZZH couplings by as much as a factor of 3. In addition, the contamination from the ZZH vertex contributions present in the measurement of the trilinear Higgs-W (WWH) couplings can be reduced to a great extent by employing polarized beams. The effects of initial state radiation and beamstrahlung, which can be relevant for higher values of the beam energy are also included in the analysis.

  5. Indirect Probe of Electroweak-Interacting Particles at Future Lepton Colliders

    International Nuclear Information System (INIS)

    Harigaya, Keisuke

    2015-04-01

    Various types of electroweak-interacting particles, which have non-trivial charges under the SU(2) L x U(1) Y gauge symmetry, appear in various extensions of the Standard Model. These particles are good targets of future lepton colliders, such as the International Linear Collider (ILC), the Compact LInear Collider (CLIC) and the Future Circular Collider of electrons and positrons (FCC-ee). An advantage of the experiments is that, even if their beam energies are below the threshold of the production of the new particles, quantum effects of the particles can be detected through high precision measurements. We estimate the capability of future lepton colliders to probe electroweak-interacting particles through the quantum effects, with particular focus on the wino, the Higgsino and the so-called minimal dark matters, and found that a particle whose mass is greater than the beam energy by 100-1000 GeV is detectable by measuring di-fermion production cross sections with O(0.1)% accuracy. In addition, with the use of the same analysis, we also discuss the sensitivity of the future colliders to model independent higher dimensional operators, and found that the cutoff scales corresponding to the operators can be probed up to a few ten TeV.

  6. Indirect probe of electroweak-interacting particles at future lepton colliders

    International Nuclear Information System (INIS)

    Harigaya, Keisuke; Ichikawa, Koji; Kundu, Anirban; Matsumoto, Shigeki; Shirai, Satoshi

    2015-01-01

    Various types of electroweak-interacting particles, which have non-trivial charges under the SU(2)_L×U(1)_Y gauge symmetry, appear in various extensions of the Standard Model. These particles are good targets of future lepton colliders, such as the International Linear Collider (ILC), the Compact LInear Collider (CLIC) and the Future Circular Collider of electrons and positrons (FCC-ee). An advantage of the experiments is that, even if their beam energies are below the threshold of the production of the new particles, quantum effects of the particles can be detected through high precision measurements. We estimate the capability of future lepton colliders to probe electroweak-interacting particles through the quantum effects, with particular focus on the wino, the Higgsino and the so-called minimal dark matters, and found that a particle whose mass is greater than the beam energy by 100–1000 GeV is detectable by measuring di-fermion production cross sections with O(0.1)% accuracy. In addition, with the use of the same analysis, we also discuss the sensitivity of the future colliders to model independent higher dimensional operators, and found that the cutoff scales corresponding to the operators can be probed up to a few ten TeV.

  7. Solar neutrinos as a probe of dark matter-neutrino interactions

    Energy Technology Data Exchange (ETDEWEB)

    Capozzi, Francesco; Vecchi, Luca [Dipartimento di Fisica e Astronomia, Università di Padova, via Marzolo 8, I-35131 Padova (Italy); Shoemaker, Ian M., E-mail: capozzi.12@osu.edu, E-mail: ian.shoemaker@usd.edu, E-mail: vecchi@infn.pd.it [Department of Physics, University of South Dakota, Vermillion, SD 57069 (United States)

    2017-07-01

    Sterile neutrinos at the eV scale have long been studied in the context of anomalies in short baseline neutrino experiments. Their cosmology can be made compatible with our understanding of the early Universe provided the sterile neutrino sector enjoys a nontrivial dynamics with exotic interactions, possibly providing a link to the Dark Matter (DM) puzzle. Interactions between DM and neutrinos have also been proposed to address the long-standing 'missing satellites' problem in the field of large scale structure formation. Motivated by these considerations, in this paper we discuss realistic scenarios with light steriles coupled to DM . We point out that within this framework active neutrinos acquire an effective coupling to DM that manifests itself as a new matter potential in the propagation within a medium of asymmetric DM . Assuming that at least a small fraction of asymmetric DM has been captured by the Sun, we show that a sizable region of the parameter space of these scenarios can be probed by solar neutrino experiments, especially in the regime of small couplings and light mediators where all other probes become inefficient. In the latter regime these scenarios behave as familiar 3+1 models in all channels except for solar data, where a Solar Dark MSW effect takes place. Solar Dark MSW is characterized by modifications of the most energetic {sup 8}B and CNO neutrinos, whereas the other fluxes remain largely unaffected.

  8. Exact dimension estimation of interacting qubit systems assisted by a single quantum probe

    Science.gov (United States)

    Sone, Akira; Cappellaro, Paola

    2017-12-01

    Estimating the dimension of an Hilbert space is an important component of quantum system identification. In quantum technologies, the dimension of a quantum system (or its corresponding accessible Hilbert space) is an important resource, as larger dimensions determine, e.g., the performance of quantum computation protocols or the sensitivity of quantum sensors. Despite being a critical task in quantum system identification, estimating the Hilbert space dimension is experimentally challenging. While there have been proposals for various dimension witnesses capable of putting a lower bound on the dimension from measuring collective observables that encode correlations, in many practical scenarios, especially for multiqubit systems, the experimental control might not be able to engineer the required initialization, dynamics, and observables. Here we propose a more practical strategy that relies not on directly measuring an unknown multiqubit target system, but on the indirect interaction with a local quantum probe under the experimenter's control. Assuming only that the interaction model is given and the evolution correlates all the qubits with the probe, we combine a graph-theoretical approach and realization theory to demonstrate that the system dimension can be exactly estimated from the model order of the system. We further analyze the robustness in the presence of background noise of the proposed estimation method based on realization theory, finding that despite stringent constrains on the allowed noise level, exact dimension estimation can still be achieved.

  9. Probing the interactions between lignin and inorganic oxides using atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jingyu; Qian, Yong, E-mail: qianyong86@163.com; Deng, Yonghong; Liu, Di; Li, Hao; Qiu, Xueqing, E-mail: xueqingqiu66@163.com

    2016-12-30

    Graphical abstract: The interactions between lignin and inorganic oxides are quantitatively probed by atomic force microscopy, which is fundamental but beneficial for understanding and optimizing the absorption-dispersion and catalytic degradation processes of lignin. - Highlights: • The interactions between lignin and inorganic oxides are measured using AFM. • The adhesion forces between lignin and metal oxides are larger than that in nonmetal systems. • Hydrogen bond plays an important role in lignin-inorganic oxides system. - Abstract: Understanding the interactions between lignin and inorganic oxides has both fundamental and practical importance in industrial and energy fields. In this work, the specific interactions between alkali lignin (AL) and three inorganic oxide substrates in aqueous environment are quantitatively measured using atomic force microscopy (AFM). The results show that the average adhesion force between AL and metal oxide such as Al{sub 2}O{sub 3} or MgO is nearly two times bigger than that between AL and nonmetal oxide such as SiO{sub 2} due to the electrostatic difference and cation-π interaction. When 83% hydroxyl groups of AL is blocked by acetylation, the adhesion forces between AL and Al{sub 2}O{sub 3}, MgO and SiO{sub 2} decrease 43, 35 and 75% respectively, which indicate hydrogen bonds play an important role between AL and inorganic oxides, especially in AL-silica system.

  10. Probing the interaction of brain fatty acid binding protein (B-FABP with model membranes.

    Directory of Open Access Journals (Sweden)

    Fábio Dyszy

    Full Text Available Brain fatty acid-binding protein (B-FABP interacts with biological membranes and delivers polyunsaturated fatty acids (FAs via a collisional mechanism. The binding of FAs in the protein and the interaction with membranes involve a motif called "portal region", formed by two small α-helices, A1 and A2, connected by a loop. We used a combination of site-directed mutagenesis and electron spin resonance to probe the changes in the protein and in the membrane model induced by their interaction. Spin labeled B-FABP mutants and lipidic spin probes incorporated into a membrane model confirmed that B-FABP interacts with micelles through the portal region and led to structural changes in the protein as well in the micelles. These changes were greater in the presence of LPG when compared to the LPC models. ESR spectra of B-FABP labeled mutants showed the presence of two groups of residues that responded to the presence of micelles in opposite ways. In the presence of lysophospholipids, group I of residues, whose side chains point outwards from the contact region between the helices, had their mobility decreased in an environment of lower polarity when compared to the same residues in solution. The second group, composed by residues with side chains situated at the interface between the α-helices, experienced an increase in mobility in the presence of the model membranes. These modifications in the ESR spectra of B-FABP mutants are compatible with a less ordered structure of the portal region inner residues (group II that is likely to facilitate the delivery of FAs to target membranes. On the other hand, residues in group I and micelle components have their mobilities decreased probably as a result of the formation of a collisional complex. Our results bring new insights for the understanding of the gating and delivery mechanisms of FABPs.

  11. Residue-Specific Side-Chain Polymorphisms via Particle Belief Propagation.

    Science.gov (United States)

    Ghoraie, Laleh Soltan; Burkowski, Forbes; Li, Shuai Cheng; Zhu, Mu

    2014-01-01

    Protein side chains populate diverse conformational ensembles in crystals. Despite much evidence that there is widespread conformational polymorphism in protein side chains, most of the X-ray crystallography data are modeled by single conformations in the Protein Data Bank. The ability to extract or to predict these conformational polymorphisms is of crucial importance, as it facilitates deeper understanding of protein dynamics and functionality. In this paper, we describe a computational strategy capable of predicting side-chain polymorphisms. Our approach extends a particular class of algorithms for side-chain prediction by modeling the side-chain dihedral angles more appropriately as continuous rather than discrete variables. Employing a new inferential technique known as particle belief propagation, we predict residue-specific distributions that encode information about side-chain polymorphisms. Our predicted polymorphisms are in relatively close agreement with results from a state-of-the-art approach based on X-ray crystallography data, which characterizes the conformational polymorphisms of side chains using electron density information, and has successfully discovered previously unmodeled conformations.

  12. Distinguishing magnetic and electrostatic interactions by a Kelvin probe force microscopy–magnetic force microscopy combination

    Directory of Open Access Journals (Sweden)

    Miriam Jaafar

    2011-09-01

    Full Text Available The most outstanding feature of scanning force microscopy (SFM is its capability to detect various different short and long range interactions. In particular, magnetic force microscopy (MFM is used to characterize the domain configuration in ferromagnetic materials such as thin films grown by physical techniques or ferromagnetic nanostructures. It is a usual procedure to separate the topography and the magnetic signal by scanning at a lift distance of 25–50 nm such that the long range tip–sample interactions dominate. Nowadays, MFM is becoming a valuable technique to detect weak magnetic fields arising from low dimensional complex systems such as organic nanomagnets, superparamagnetic nanoparticles, carbon-based materials, etc. In all these cases, the magnetic nanocomponents and the substrate supporting them present quite different electronic behavior, i.e., they exhibit large surface potential differences causing heterogeneous electrostatic interaction between the tip and the sample that could be interpreted as a magnetic interaction. To distinguish clearly the origin of the tip–sample forces we propose to use a combination of Kelvin probe force microscopy (KPFM and MFM. The KPFM technique allows us to compensate in real time the electrostatic forces between the tip and the sample by minimizing the electrostatic contribution to the frequency shift signal. This is a great challenge in samples with low magnetic moment. In this work we studied an array of Co nanostructures that exhibit high electrostatic interaction with the MFM tip. Thanks to the use of the KPFM/MFM system we were able to separate the electric and magnetic interactions between the tip and the sample.

  13. The interaction of a nanoscale coherent helium-ion probe with a crystal

    International Nuclear Information System (INIS)

    D'Alfonso, A.J.; Forbes, B.D.; Allen, L.J.

    2013-01-01

    Thickness fringing was recently observed in helium ion microscopy (HIM) when imaging magnesium oxide cubes using a 40 keV convergent probe in scanning transmission mode. Thickness fringing is also observed in electron microscopy and is due to quantum mechanical, coherent, multiple elastic scattering attenuated by inelastic phonon excitation (thermal scattering). A quantum mechanical model for elastic scattering and phonon excitation correctly models the thickness fringes formed by the helium ions. However, unlike the electron case, the signal in the diffraction plane is due mainly to the channeling of ions which have first undergone inelastic thermal scattering in the first few atomic layers so that the origin of the thickness fringes is not due to coherent interference effects. This quantum mechanical model affords insight into the interaction of a nanoscale, focused coherent ion probe with the specimen and allows us to elucidate precisely what is needed to achieve atomic resolution HIM. - Highlights: • Thickness fringing has recently been observed imaging MgO cubes using helium ion microscopy. • A quantum mechanical model for elastic scattering and phonon excitation models the fringes. • The signal is due mainly to the coherent scattering of ions after inelastic thermal scattering. • We elucidate precisely what is needed to achieve atomic resolution HIM

  14. Electron-muon correlation as a new probe of strongly interacting quark-gluon plasma

    International Nuclear Information System (INIS)

    Akamatsu, Yukinao; Hatsuda, Tetsuo; Hirano, Tetsufumi

    2009-01-01

    As a new and clean probe to the strongly interacting quark-gluon plasma (sQGP), we propose an azimuthal correlation of an electron and a muon that originate from the semileptonic decay of charm and bottom quarks. By solving the Langevin equation for the heavy quarks under the hydrodynamic evolution of the hot plasma, we show that substantial quenching of the away-side peak in the electron-muon correlation can be seen if the sQGP drag force acting on heavy quarks is large enough as suggested from the gauge/gravity correspondence. The effect could be detected in high-energy heavy ion collisions at the Relativistic Heavy Ion Collider and the Large Hadron Collider.

  15. Measurement of the target current by inductive probe during laser interaction on terawatt laser system PALS

    Czech Academy of Sciences Publication Activity Database

    Cikhardt, Jakub; Krása, Josef; De Marco, Massimo; Pfeifer, Miroslav; Velyhan, Andriy; Krouský, Eduard; Cikhardtová, B.; Klír, Daniel; Řezáč, Karel; Ullschmied, Jiří; Skála, Jiří; Kubeš, P.; Kravárik, J.

    2014-01-01

    Roč. 85, č. 10 (2014), s. 103507-103507 ISSN 0034-6748 R&D Projects: GA MŠk LM2010014; GA MŠk(CZ) LG13029; GA ČR GAP205/12/0454; GA MŠk EE2.3.20.0279 Grant - others:LaserZdroj (OP VK 3)(XE) CZ.1.07/2.3.00/20.0279 Institutional support: RVO:61389021 ; RVO:68378271 Keywords : laser PALS * laser-target interaction * target current * inductive probe Subject RIV: BL - Plasma and Gas Discharge Physics; BL - Plasma and Gas Discharge Physics (FZU-D) Impact factor: 1.614, year: 2014 http://dx.doi.org/10.1063/1.4898016

  16. Probing SU(N)-symmetric orbital interactions with ytterbium Fermi gases in optical lattices

    International Nuclear Information System (INIS)

    Scazza, Francesco

    2015-01-01

    This thesis reports on the creation and investigation of interacting two-orbital quantum gases of ytterbium in optical lattices. Degenerate fermionic gases of ytterbium or other alkaline-earth-like atoms have been recently proposed as model systems for orbital phenomena in condensed matter, such as Kondo screening, heavy-Fermi behaviour and colossal magnetoresistance. Such gases are moreover expected to obey a high SU(N) symmetry, owing to their highly decoupled nuclear spin, for which the emergence of novel, exotic phases of matter has been predicted. With the two lowest (meta-) stable electronic states mimicking electrons in distinct orbitals of solid materials, the two-orbital SU(N) Hubbard model and its spin-exchange inter-orbital interactions are realised. The interactions in two-orbital degenerate mixtures of different nuclear spin states of 173 Yb are probed by addressing the transition to the metastable state in a state-independent optical lattice. The complete characterisation of the two-orbital scattering channels and the demonstration of the SU(N=6) symmetry within the experimental uncertainty are presented. Most importantly, a strong spin- exchange coupling between the two orbitals is identified and the associated exchange process is observed through the dynamic equilibration of spin imbalances between ensembles in different orbitals. These findings are enabled by the implementation of high precision spectroscopic techniques and of full coherent control of the metastable state population. The realisation of SU(N)-symmetric gases with spin-exchange interactions, the elementary building block of orbital quantum magnetism, represents an important step towards the simulation of paradigmatic many-body models, such as the Kondo lattice model.

  17. Probing Induced Structural Changes in Biomimetic Bacterial Cell Membrane Interactions with Divalent Cations

    Energy Technology Data Exchange (ETDEWEB)

    Holt, Allison M [ORNL; Standaert, Robert F [ORNL; Jubb, Aaron M [ORNL; Katsaras, John [ORNL; Johs, Alexander [ORNL

    2017-01-01

    Biological membranes, formed primarily by the self-assembly of complex mixtures of phospholipids, provide a structured scaffold for compartmentalization and structural processes in living cells. The specific physical properties of phospholipid species present in a given membrane play a key role in mediating these processes. Phosphatidylethanolamine (PE), a zwitterionic lipid present in bacterial, yeast, and mammalian cell membranes, is exceptional. In addition to undergoing the standard lipid polymorphic transition between the gel and liquid-crystalline phase, it can also assume an unusual polymorphic state, the inverse hexagonal phase (HII). Divalent cations are among the factors that drive the formation of the HII phase, wherein the lipid molecules form stacked tubular structures by burying the hydrophilic head groups and exposing the hydrophobic tails to the bulk solvent. Most biological membranes contain a lipid species capable of forming the HII state suggesting that such lipid polymorphic structural states play an important role in structural biological processes such as membrane fusion. In this study, the interactions between Mg2+ and biomimetic bacterial cell membranes composed of PE and phosphatidylglycerol (PG) were probed using differential scanning calorimetry (DSC), small-angle x-ray scattering (SAXS), and fluorescence spectroscopy. The lipid phase transitions were examined at varying ratios of PE to PG and upon exposure to physiologically relevant concentrations of Mg2+. An understanding of these basic interactions enhances our understanding of membrane dynamics and how membrane-mediated structural changes may occur in vivo.

  18. Optical response of a quantum dot-metal nanoparticle hybrid interacting with a weak probe field.

    Science.gov (United States)

    Kosionis, Spyridon G; Terzis, Andreas F; Sadeghi, Seyed M; Paspalakis, Emmanuel

    2013-01-30

    We study optical effects in a hybrid system composed of a semiconductor quantum dot and a spherical metal nanoparticle that interacts with a weak probe electromagnetic field. We use modified nonlinear density matrix equations for the description of the optical properties of the system and obtain a closed-form expression for the linear susceptibilities of the quantum dot, the metal nanoparticle, and the total system. We then investigate the dependence of the susceptibility on the interparticle distance as well as on the material parameters of the hybrid system. We find that the susceptibility of the quantum dot exhibits optical transparency for specific frequencies. In addition, we show that there is a range of frequencies of the applied field for which the susceptibility of the semiconductor quantum dot leads to gain. This suggests that in such a hybrid system quantum coherence can reverse the course of energy transfer, allowing flow of energy from the metallic nanoparticle to the quantum dot. We also explore the susceptibility of the metal nanoparticle and show that it is strongly influenced by the presence of the quantum dot.

  19. Probing the interaction of microscopic material defects with quasiparticles using a superconducting qubit

    Energy Technology Data Exchange (ETDEWEB)

    Bilmes, Alexander; Lisenfeld, Juergen; Weiss, Georg; Ustinov, Alexey V. [PI, Fakultaet fuer Physik, KIT, Wolfgang-Gaede-Strasse 1, 76131 Karlsruhe (Germany); Heimes, Andreas; Zanker, Sebastian; Schoen, Gerd [TFP, Fakultaet fuer Physik, KIT, Wolfgang-Gaede-Strasse 1, 76131 Karlsruhe (Germany)

    2015-07-01

    Two-Level-Systems (TLS) are one of the main sources of decoherence in superconducting nano-scale devices such as SQUIDs, photon detectors, resonators and quantum bits (qubits), although the TLS' microscopic nature remains unclear. We use a superconducting phase qubit to detect TLS contained within the tunnel barrier of the qubit's Josephson junction. We coherently operate individual TLS by resonant microwave pulses and access their quantum state by utilizing their strong coupling to the qubit. Our previous measurements of TLS coherence in dependence of the temperature indicate that quasiparticles may give rise to TLS energy loss and dephasing. Here, we probe the TLS-quasiparticle interaction using a reliable method of in-situ quasiparticle injection via an on-chip dc-SQUID that is pulse-biased beyond its critical current. The quasiparticle density is calibrated by measuring associated characteristic changes to the qubit's resonance frequency and energy relaxation rate. We will present experimental data that clearly show the influence of quasiparticles on TLS coherence.

  20. Assorted interactions of amino acids prevailing in aqueous vitamin C solutions probed by physicochemical and ab-initio contrivances

    Science.gov (United States)

    Das, Koyeli; Roy, Milan Chandra; Rajbanshi, Biplab; Roy, Mahendra Nath

    2017-11-01

    Qualitative and quantitative analysis of molecular interaction prevailing in tyrosine and tryptophan in aqueous solution of vitamin C have been probed by thermophysical properties. The apparent molar volume (ϕV), viscosity B-coefficient, molal refraction (RM) of tyrosine and tryptophan have been studied in aqueous vitamin C solutions at diverse temperatures via Masson equation which deduced solute-solvent and solute-solute interactions, respectively. Spectroscopic study along with physicochemical and computational techniques provides lots of interesting and highly significant insights of the model biological systems. The overall results established strong solute-solvent interactions between studied amino acids and vitamin C mixture in the ternary solutions.

  1. An inverse method for determining the interaction force between the probe and sample using scanning near-field optical microscopy

    International Nuclear Information System (INIS)

    Chang, Win-Jin; Fang, Te-Hua

    2006-01-01

    This study proposes a means for calculating the interaction force during the scanning process using a scanning near-field optical microscope (SNOM) probe. The determination of the interaction force in the scanning system is regarded as an inverse vibration problem. The conjugate gradient method is applied to treat the inverse problem using available displacement measurements. The results show that the conjugate gradient method is less sensitive to measurement errors and prior information on the functional form of quality was not required. Furthermore, the initial guesses for the interaction force can be arbitrarily chosen for the iteration process

  2. Vertical wind velocity measurements using a five-hole probe with remotely piloted aircraft to study aerosol–cloud interactions

    Directory of Open Access Journals (Sweden)

    R. Calmer

    2018-05-01

    Full Text Available The importance of vertical wind velocities (in particular positive vertical wind velocities or updrafts in atmospheric science has motivated the need to deploy multi-hole probes developed for manned aircraft in small remotely piloted aircraft (RPA. In atmospheric research, lightweight RPAs ( <  2.5 kg are now able to accurately measure atmospheric wind vectors, even in a cloud, which provides essential observing tools for understanding aerosol–cloud interactions. The European project BACCHUS (impact of Biogenic versus Anthropogenic emissions on Clouds and Climate: towards a Holistic UnderStanding focuses on these specific interactions. In particular, vertical wind velocity at cloud base is a key parameter for studying aerosol–cloud interactions. To measure the three components of wind, a RPA is equipped with a five-hole probe, pressure sensors, and an inertial navigation system (INS. The five-hole probe is calibrated on a multi-axis platform, and the probe–INS system is validated in a wind tunnel. Once mounted on a RPA, power spectral density (PSD functions and turbulent kinetic energy (TKE derived from the five-hole probe are compared with sonic anemometers on a meteorological mast. During a BACCHUS field campaign at Mace Head Atmospheric Research Station (Ireland, a fleet of RPAs was deployed to profile the atmosphere and complement ground-based and satellite observations of physical and chemical properties of aerosols, clouds, and meteorological state parameters. The five-hole probe was flown on straight-and-level legs to measure vertical wind velocities within clouds. The vertical velocity measurements from the RPA are validated with vertical velocities derived from a ground-based cloud radar by showing that both measurements yield model-simulated cloud droplet number concentrations within 10 %. The updraft velocity distributions illustrate distinct relationships between vertical cloud fields in different meteorological

  3. Scanning Probe Optical Tweezers: a new tool to study DNA-protein interactions

    NARCIS (Netherlands)

    Huisstede, J.H.G.

    2006-01-01

    The main goal of the work described in this thesis is to construct a microscope in which OT and scanning probe microscopy (SPM) are combined, to be able to localize proteins while simultaneously controlling the tension within the DNA molecule. This apparatus enables the study of the effect of

  4. An interactive tool for processing sap flux data from thermal dissipation probes

    Science.gov (United States)

    Andrew C. Oishi; Chelcy F. Miniat

    2016-01-01

    Sap flux sensors are an important tool for estimating tree-level transpiration in forested and urban ecosystems around the world. Thermal dissipation (TD) or Granier-type sap flux probes are among the most commonly used due to their reliability, simplicity, and low cost.

  5. Real-Time Probing of Structural Dynamics by Interaction between Chromophores

    DEFF Research Database (Denmark)

    Brogaard, Rasmus Y.; Møller, Klaus Braagaard; Sølling, Theis Ivan

    2011-01-01

    We present an investigation of structural dynamics in excited-state cations probed in real-time by femtosecond timeresolved ion photofragmentation spectroscopy. From photoelectron spectroscopy data on 1,3-dibromopropane we conclude that the pump pulse ionizes the molecule, populating an excited...

  6. Selective interaction between Xanthophylls and Chlorophylls in LHCII probed by femtosecond transient absoprtion spectroscopy

    NARCIS (Netherlands)

    Gradinaru, C.C.; Grondelle, van R.; Amerongen, van H.

    2003-01-01

    We have performed femtosecond transient absorption measurements on trimeric light-harvesting complex II from spinach. Either chlorophyll (Chl) a (675 nm) or Chl b (650 nm) was excited, and the spectral response was probed for wavelengths longer than 470 nm. Excitation of Chl b led to instantaneous

  7. A subnanomolar fluorescent probe for protein kinase CK2 interaction studies

    DEFF Research Database (Denmark)

    Enkvist, Erki; Viht, Kaido; Bischoff, Nils

    2012-01-01

    of the functions of CK2 could be facilitated by the application of small-molecule fluorescent probes that bind to the active site of the enzyme with high affinity and selectivity. We have used a bisubstrate approach for the development of a highly potent inhibitor of CK2. 4,5,6,7-Tetrabromo-1H-benzimidazole...

  8. Probes & Drugs portal: an interactive, open data resource for chemical biology

    Czech Academy of Sciences Publication Activity Database

    Škuta, Ctibor; Popr, M.; Muller, Tomáš; Jindřich, Jindřich; Kahle, Michal; Sedlák, David; Svozil, Daniel; Bartůněk, Petr

    2017-01-01

    Roč. 14, č. 8 (2017), s. 758-759 ISSN 1548-7091 R&D Projects: GA MŠk LO1220 Institutional support: RVO:68378050 Keywords : bioactive compound, ,, * chemical probe * chemical biology * portal Subject RIV: EB - Genetics ; Molecular Biology OBOR OECD: Computer sciences, information science, bioinformathics (hardware development to be 2.2, social aspect to be 5.8) Impact factor: 25.062, year: 2016

  9. Peptide microarrays to probe for competition for binding sites in a protein interaction network

    NARCIS (Netherlands)

    Sinzinger, M.D.S.; Ruttekolk, I.R.R.; Gloerich, J.; Wessels, H.; Chung, Y.D.; Adjobo-Hermans, M.J.W.; Brock, R.E.

    2013-01-01

    Cellular protein interaction networks are a result of the binding preferences of a particular protein and the entirety of interactors that mutually compete for binding sites. Therefore, the reconstruction of interaction networks by the accumulation of interaction networks for individual proteins

  10. Deposition of lithium on a plasma edge probe in TFTR -- Behavior of lithium-painted walls interacting with edge plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Hirooka, Y. [Univ. of California, San Diego, La Jolla, CA (United States); Ashida, K. [Toyama Univ. (Japan); Kugel, H. [Princeton Univ., NJ (United States)] [and others

    1998-05-01

    Recent observations have indicated that lithium pellet injection wall conditioning plays an important role in achieving the enhanced supershot regime in TFTR. However, little is understood about the behavior of lithium-coated limiter walls, interacting with edge plasmas. In the final campaign of TFTR, a cylindrical carbon fiber composite probe was inserted into the boundary plasma region and exposed to ohmically-heated deuterium discharges with lithium pellet injection. The ion-drift side probe surface exhibits a sign of codeposition of lithium, carbon, oxygen, and deuterium, whereas the electron side essentially indicates high-temperature erosion. It is found that lithium is incorporated in these codeposits in the form of oxide at the concentration of a few percent. In the electron side, lithium has been found to penetrate deeply into the probe material, presumably via rapid diffusion through interplane spaces in the graphite crystalline. Though it is not conclusive, materials mixing in the carbon and lithium system appears to be a key process in successful lithium wall conditioning.

  11. Coulomb drag: a probe of electron interactions in coupled quantum wells

    DEFF Research Database (Denmark)

    Jauho, Antti-Pekka

    1996-01-01

    As semiconductor devices shrink in size and in dimensionality, interactions between charge carriers become more and more important. There is a simple physical reason behind this behavior: fewer carriers lead to less effective screening, and hence stronger effective interactions. A point in case...... are one-dimensional systems (quantum wires): there electron-electron interactions may lead to a behavior, which is qualitatively different from the standard Fermi liquid picture (Luttinger liquids). Electron-electron interactions also play a central role in the fractional quantum Hall effect, which...... be the study of quantum wires: there the interactions may lead to even more dramatic effects...

  12. Validation of a microdose probe drug cocktail for clinical drug interaction assessments for drug transporters and CYP3A.

    Science.gov (United States)

    Prueksaritanont, T; Tatosian, D A; Chu, X; Railkar, R; Evers, R; Chavez-Eng, C; Lutz, R; Zeng, W; Yabut, J; Chan, G H; Cai, X; Latham, A H; Hehman, J; Stypinski, D; Brejda, J; Zhou, C; Thornton, B; Bateman, K P; Fraser, I; Stoch, S A

    2017-04-01

    A microdose cocktail containing midazolam, dabigatran etexilate, pitavastatin, rosuvastatin, and atorvastatin has been established to allow simultaneous assessment of a perpetrator impact on the most common drug metabolizing enzyme, cytochrome P450 (CYP)3A, and the major transporters organic anion-transporting polypeptides (OATP)1B, breast cancer resistance protein (BCRP), and MDR1 P-glycoprotein (P-gp). The clinical utility of these microdose cocktail probe substrates was qualified by conducting clinical drug interaction studies with three inhibitors with different in vitro inhibitory profiles (rifampin, itraconazole, and clarithromycin). Generally, the pharmacokinetic profiles of the probe substrates, in the absence and presence of the inhibitors, were comparable to their reported corresponding pharmacological doses, and/or in agreement with theoretical expectations. The exception was dabigatran, which resulted in an approximately twofold higher magnitude for microdose compared to conventional dosing, and, thus, can be used to flag a worst-case scenario for P-gp. Broader application of the microdose cocktail will facilitate a more comprehensive understanding of the roles of drug transporters in drug disposition and drug interactions. © 2016 American Society for Clinical Pharmacology and Therapeutics.

  13. AC susceptibility as a tool to probe the dipolar interaction in magnetic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Landi, Gabriel T., E-mail: gtlandi@gmail.com [Universidade Federal do ABC, 09210-580 Santo André (Brazil); Arantes, Fabiana R. [Universidade Federal do ABC, 09210-580 Santo André (Brazil); Cornejo, Daniel R. [Instituto de Física da Universidade de São Paulo, São Paulo 05508-090 (Brazil); Bakuzis, Andris F. [Instituto de Física, Universidade Federal de Goiás, 74690-900 Goiânia-GO (Brazil); Andreu, Irene; Natividad, Eva [Instituto de Ciencia de Materiales de Aragón (ICMA), CSIC-Universidad de Zaragoza, Zaragoza 50018 (Spain)

    2017-01-01

    The dipolar interaction is known to substantially affect the properties of magnetic nanoparticles. This is particularly important when the particles are kept in a fluid suspension or packed within nano-carriers. In addition to its usual long-range nature, in these cases the dipolar interaction may also induce the formation of clusters of particles, thereby strongly modifying their magnetic anisotropies. In this paper we show how AC susceptibility may be used to obtain information regarding the influence of the dipolar interaction in a sample. We develop a model which includes both aspects of the dipolar interaction and may be fitted directly to the susceptibility data. The usual long-range nature of the interaction is implemented using a mean-field approximation, whereas the particle-particle aggregation is modeled using a distribution of anisotropy constants. The model is then applied to two samples studied at different concentrations. One consists of spherical magnetite nanoparticles dispersed in oil and the other of cubic magnetite nanoparticles embedded on polymeric nanospheres. We also introduce a simple technique to address the presence of the dipolar interaction in a given sample, based on the height of the AC susceptibility peaks for different driving frequencies. - Highlights: We discuss the importance of the dipolar interaction in magnetic nanoparticle samples. It is shown that AC susceptibility may be used to estimate the extent of this interaction. We develop a model that accounts for particle aggregation. The theoretical model is then fitted to distinct magnetite samples.

  14. N(1)-methylnicotinamide as an endogenous probe for drug interactions by renal cation transporters: studies on the metformin-trimethoprim interaction.

    Science.gov (United States)

    Müller, Fabian; Pontones, Constanza A; Renner, Bertold; Mieth, Maren; Hoier, Eva; Auge, Daniel; Maas, Renke; Zolk, Oliver; Fromm, Martin F

    2015-01-01

    N(1)-methylnicotinamide (NMN) was proposed as an in vivo probe for drug interactions involving renal cation transporters, which, for example, transport the oral antidiabetic drug metformin, based on a study with the inhibitor pyrimethamine. The role of NMN for predicting other interactions with involvement of renal cation transporters (organic cation transporter 2, OCT2; multidrug and toxin extrusion proteins 1 and 2-K, MATE1 and MATE2-K) is unclear. We determined inhibition of metformin or NMN transport by trimethoprim using cell lines expressing OCT2, MATE1, or MATE2-K. Moreover, a randomized, open-label, two-phase crossover study was performed in 12 healthy volunteers. In each phase, 850 mg metformin hydrochloride was administered p.o. in the evening of day 4 and in the morning of day 5. In phase B, 200 mg trimethoprim was administered additionally p.o. twice daily for 5 days. Metformin pharmacokinetics and effects (measured by OGTT) and NMN pharmacokinetics were determined. Trimethoprim inhibited metformin transport with K i values of 27.2, 6.3, and 28.9 μM and NMN transport with IC50 values of 133.9, 29.1, and 0.61 μM for OCT2, MATE1, and MATE2-K, respectively. In the clinical study, trimethoprim increased metformin area under the plasma concentration-time curve (AUC) by 29.5 % and decreased metformin and NMN renal clearances by 26.4 and 19.9 %, respectively (p ≤ 0.01). Moreover, decreases of NMN and metformin renal clearances due to trimethoprim correlated significantly (r S=0.727, p=0.010). These data on the metformin-trimethoprim interaction support the potential utility of N(1)-methylnicotinamide as an endogenous probe for renal drug-drug interactions with involvement of renal cation transporters.

  15. Equilibration of a strongly interacting plasma: holographic analysis of local and nonlocal probes

    Directory of Open Access Journals (Sweden)

    Bellantuono Loredana

    2016-01-01

    Full Text Available The relaxation of a strongly coupled plasma towards the hydrodynamic regime is studied by analyzing the evolution of local and nonlocal observables in the holographic approach. The system is driven in an initial anisotropic and far-from equilibrium state through an impulsive time-dependent deformation (quench of the boundary spacetime geometry. Effective temperature and entropy density are related to the position and area of a black hole horizon, which has formed as a consequence of the distortion. The behavior of stress-energy tensor, equal-time correlation functions and Wilson loops of different shapes is examined, and a hierarchy among their thermalization times emerges: probes involving shorter length scales thermalize faster.

  16. Probing the Interaction of Ionic Liquids with CO2: A Raman Spectroscopy and Ab Initio Study

    National Research Council Canada - National Science Library

    Eucker, IV, William

    2008-01-01

    ...) with selected ionic liquids (ILs). Raman spectroscopy and first principle quantum mechanical calculations were performed on selected IL solvents in contact with CO2 in the effort to discover how the solvents interact with the gas. ILs are salts...

  17. A direct probe of dark energy interactions with a solar System laboratory

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose a mission concept for direct detection of dark energy interactions with normal matter in a Solar System laboratory. Dark energy is the leading proposal to...

  18. Probing nanoparticle-macromolecule interaction and resultant structure by small-angle neutron scattering

    International Nuclear Information System (INIS)

    Aswal, V.K.

    2013-01-01

    Nanoparticles display unique and distinct characteristics from those of their constituent atoms and bulk materials which are being employed in numerous applications in the fields of medicine, electronics, optics, communications, energy, environment etc. Many of these applications require adjoining of nanoparticles with macromolecules such as proteins, polymers and surfactants to obtain functional objects. For example, nanoparticle-protein complexes are of great importance in controlling enzymatic behavior, targeted drug delivery and developing biocompatible materials. The nanoparticles interfaced with polymers are shown to be useful in developing protein sensor arrays. Interaction of surfactants with nanoparticles is utilized extensively for technical and industrial applications associated with colloidal stability, detergency and design of nanostructured functional interfaces. The interaction of two components, nanoparticles and macromolecule, strongly depends on the characteristics of both the nanoparticles (size, shape, surface roughness, charge density etc.) and macromolecules (type, charge, shape and solution conditions etc.) used. The interaction of macromolecule on nanoparticle surface is a cumulative effect of a number of forces such as electrostatic force, covalent bonding, hydrogen bonding, non-polar interaction, hydrophobic interactions etc. These interactions depending on the system conditions can lead to various structures. Small-angle neutron scattering (SANS) with the possibility to vary contrast is an ideal technique to study such multi-component systems. In this talk, some of our results of SANS from the complexes of nanoparticle-protein and nanoparticle surfactant systems will be discussed. (author)

  19. Probing dark matter self-interaction in the Sun with IceCube-PINGU

    International Nuclear Information System (INIS)

    Chen, Chian-Shu; Lee, Fei-Fan; Lin, Guey-Lin; Lin, Yen-Hsun

    2014-01-01

    We study the capture, annihilation and evaporation of dark matter (DM) inside the Sun. It has been shown that the DM self-interaction can increase the DM number inside the Sun. We demonstrate that this enhancement becomes more significant in the regime of small DM mass, given a fixed DM self-interaction cross section. This leads to the enhancement of neutrino flux from DM annihilation. On the other hand, for DM mass as low as as a few GeVs, not only the DM-nuclei scatterings can cause the DM evaporation, DM self-interaction also provides non-negligible contributions to this effect. Consequently, the critical mass for DM evaporation (typically 3 ∼ 4 GeV without the DM self-interaction) can be slightly increased. We discuss the prospect of detecting DM self-interaction in IceCube-PINGU using the annihilation channels χχ → τ + τ - , νν-bar as examples. The PINGU sensitivities to DM self-interaction cross section σ χχ are estimated for track and cascade events

  20. Probing the stereoselective interaction of ofloxacin enantiomers with corresponding monoclonal antibodies by multiple spectrometry

    Science.gov (United States)

    Mu, Hongtao; Xu, Zhenlin; Liu, Yingju; Sun, Yuanming; Wang, Baoling; Sun, Xiulan; Wang, Zhanhui; Eremin, Sergei; Zherdev, Anatoly V.; Dzantiev, Boris B.; Lei, Hongtao

    2018-04-01

    Although stereoselective antibody has immense potential in chiral compounds detection and separation, the interaction traits between stereoselective antibody and the corresponding antigenic enantiomers are not yet fully exploited. In this study, the stereospecific interactions between ofloxacin isomers and corresponding monoclonal antibodies (McAb-WR1 and McAb-MS1) were investigated using time-resolved fluorescence, steady-state fluorescence, and circular dichroism (CD) spectroscopic methods. The chiral recognition discrepancies of antibodies with ofloxacin isomers were reflected through binding constant, number of binding sites, driving forces and conformational changes. The major interacting forces of McAb-WR1 and McAb-MS1 chiral interaction systems were hydrophobic force and van der Waals forces joined up with hydrogen bonds, respectively. Synchronous fluorescence spectra and CD spectra results showed that the disturbing of tyrosine and tryptophan micro-environments were so slightly that no obvious secondary structure changes were found during the chiral hapten binding. Clarification of stereospecific interaction of antibody will facilitate the application of immunoassay to analyze chiral contaminants in food and other areas.

  1. Using ATTO dyes to probe bacterial interactions with the marine diatom Pseudo-nitzschia.

    Science.gov (United States)

    Mehic, S.; Sison-Mangus, M.

    2016-02-01

    Pseudo-nitzschia blooms are known to be highly toxic and detrimental to wildlife. The neurotoxin produced by the algae can ripple through the entire food web creating a direct impact on oceanic life and human-related industries. With coastal blooms increasing in both size and duration in recent years, it is crucial that we uncover more microbial interactions that may affect the toxicity of these blooms. Current harmful algal bloom studies have shown that different bacterial consortia can have a great impact Pseudo-nitzschia physiology. More specifically, research suggests that bacteria affect both growth rates and domoic acid concentrations of laboratory grown cultures. However, these studies do not explore the attachment patterns of these bacteria with the diatom. Bacterial attachment may dictate the different types of interactions between bacteria and the diatoms, a trait that is largely unexplored in the symbiotic interactions between the two organisms. In this study, we seek to identify direct and indirect interactions between four bacteria taxa from different phyla and three different species of Pseudo-nitzschia. Our preliminary scanning electron microscopy and DAPI staining experiments hint at distinct differences in attachment among bacterial taxa. To explore this work further, we aim to employ ATTO dyes and epifluorescent microscopy on both binary and multiple cultures to visualize patterns in attachment. By utilizing ATTO dyes with distinct wavelength emissions, we can perform a series experiment that highlights the interaction between bacteria and diatoms, without inserting a fluorescent reporter gene in the bacteria. Multiple cultures will be used to identify possible cooperative or negative interactive traits between bacteria that can affect diatom host physiology. Implications on both phytoplankton physiology and nutrient cycling will be subsequently discussed.

  2. Dynamical instability of a spin spiral in an interacting Fermi gas as a probe of the Stoner transition

    Science.gov (United States)

    Conduit, G. J.; Altman, E.

    2010-10-01

    We propose an experiment to probe ferromagnetic phenomena in an ultracold Fermi gas, while alleviating the sensitivity to three-body loss and competing many-body instabilities. The system is initialized in a small pitch spin spiral, which becomes unstable in the presence of repulsive interactions. To linear order the exponentially growing collective modes exhibit critical slowing down close to the Stoner transition point. Also, to this order, the dynamics are identical on the paramagnetic and ferromagnetic sides of the transition. However, we show that scattering off the exponentially growing modes qualitatively alters the collective mode structure. The critical slowing down is eliminated and in its place a new unstable branch develops at large wave vectors. Furthermore, long-wavelength instabilities are quenched on the paramagnetic side of the transition. We study the experimental observation of the instabilities, specifically addressing the trapping geometry and how phase-contrast imaging will reveal the emerging domain structure. These probes of the dynamical phenomena could allow experiments to detect the transition point and distinguish between the paramagnetic and ferromagnetic regimes.

  3. Dynamical instability of a spin spiral in an interacting Fermi gas as a probe of the Stoner transition

    International Nuclear Information System (INIS)

    Conduit, G. J.; Altman, E.

    2010-01-01

    We propose an experiment to probe ferromagnetic phenomena in an ultracold Fermi gas, while alleviating the sensitivity to three-body loss and competing many-body instabilities. The system is initialized in a small pitch spin spiral, which becomes unstable in the presence of repulsive interactions. To linear order the exponentially growing collective modes exhibit critical slowing down close to the Stoner transition point. Also, to this order, the dynamics are identical on the paramagnetic and ferromagnetic sides of the transition. However, we show that scattering off the exponentially growing modes qualitatively alters the collective mode structure. The critical slowing down is eliminated and in its place a new unstable branch develops at large wave vectors. Furthermore, long-wavelength instabilities are quenched on the paramagnetic side of the transition. We study the experimental observation of the instabilities, specifically addressing the trapping geometry and how phase-contrast imaging will reveal the emerging domain structure. These probes of the dynamical phenomena could allow experiments to detect the transition point and distinguish between the paramagnetic and ferromagnetic regimes.

  4. Electrostatic interactions in protein adsorption probed by comparing lysozyme and succinylated lysozyme

    NARCIS (Netherlands)

    Veen, van der M.; Norde, W.; Cohen Stuart, M.A.

    2004-01-01

    The influence of electrostatic interactions on protein adsorption was studied by comparing the adsorption of lysozyme and succinylated lysozyme at silica surfaces. The succinylation affects the charge of the protein, but also the stability. Although changes in stability can have an influence on

  5. Computational Tools for Probing Interactions in Multiple Linear Regression, Multilevel Modeling, and Latent Curve Analysis

    Science.gov (United States)

    Preacher, Kristopher J.; Curran, Patrick J.; Bauer, Daniel J.

    2006-01-01

    Simple slopes, regions of significance, and confidence bands are commonly used to evaluate interactions in multiple linear regression (MLR) models, and the use of these techniques has recently been extended to multilevel or hierarchical linear modeling (HLM) and latent curve analysis (LCA). However, conducting these tests and plotting the…

  6. Probing nanomechanical interaction at the interface between biological membrane and potentially toxic chemical.

    Science.gov (United States)

    Lim, Chanoong; Park, Sohee; Park, Jinwoo; Ko, Jina; Lee, Dong Woog; Hwang, Dong Soo

    2018-04-12

    Various xenobiotics interact with biological membranes, and precise evaluations of the molecular interactions between them are essential to foresee the toxicity and bioavailability of existing or newly synthesized molecules. In this study, surface forces apparatus (SFA) measurement and Langmuir trough based tensiometry are performed to reveal nanomechanical interaction mechanisms between potential toxicants and biological membranes for ex vivo toxicity evaluation. As a toxicant, polyhexamethylene guanidine (PHMG) was selected because PHMG containing humidifier disinfectant and Vodka caused lots of victims in both S. Korea and Russia, respectively, due to the lack of holistic toxicity evaluation of PHMG. Here, we measured strong attraction (Wad ∼4.2 mJ/m 2 ) between PHMG and head group of biological membranes while no detectable adhesion force between the head group and control molecules was measured. Moreover, significant changes in π-A isotherm of 1,2-Dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) monolayers were measured upon PHMG adsorption. These results indicate PHMG strongly binds to hydrophilic group of lipid membranes and alters the structural and phase behavior of them. More importantly, complementary utilization of SFA and Langmuir trough techniques are found to be useful to predict the potential toxicity of a chemical by evaluating the molecular interaction with biological membranes, the primary protective barrier for living organisms. Copyright © 2018 Elsevier B.V. All rights reserved.

  7. Probing molecular interactions in bone biomaterials: Through molecular dynamics and Fourier transform infrared spectroscopy

    International Nuclear Information System (INIS)

    Bhowmik, Rahul; Katti, Kalpana S.; Verma, Devendra; Katti, Dinesh R.

    2007-01-01

    Polymer-hydroxyapatite (HAP) composites are widely investigated for their potential use as bone replacement materials. The molecular interactions at mineral polymer interface are known to have significant role of mechanical response of the composite system. Modeling interactions between such dissimilar molecules using molecular dynamics (MD) is an area of current interest. Molecular dynamics studies require potential function or force field parameters. Some force fields are described in literature that represents the structure of hydroxyapatite reasonably well. Yet, the applicability of these force fields for studying the interaction between dissimilar materials (such as mineral and polymer) is limited, as there is no accurate representation of polymer in these force fields. We have obtained the parameters of consistent valence force field (CVFF) for monoclinic hydroxyapatite. Validation of parameters was done by comparing the computationally obtained unit cell parameters, vibrational spectra and atomic distances with XRD and FTIR experiments. Using the obtained parameters of HAP, and available parameters of polymer (polyacrylic acid), interaction study was performed with MD simulations. The MD simulations showed that several hydrogen bonds may form between HAP and polyacrylic acid depending upon the exposed surface of HAP. Also there are some favourable planes of HAP where polyacrylic acid is most likely to attach. We have also simulated the mineralization of HAP using a 'synthetic biomineralization'. These modeling studies are supported by photoacoustic spectroscopy experiments on both porous and non porous composite samples for potential joint replacement and bone tissue engineering applications

  8. Probing Bio-Nano Interactions between Blood Proteins and Monolayer-Stabilized Graphene Sheets

    DEFF Research Database (Denmark)

    Gan, Shiyu; Zhong, Lijie; Han, Dongxue

    2015-01-01

    Meeting proteins is regarded as the starting event for nanostructures to enter biological systems. Understanding their interactions is thus essential for a newly emerging field, nanomedicine. Chemically converted graphene (CCG) is a wonderful two-dimesional (2D) material for nanomedecine, but its...

  9. Probing the role of backbone hydrogen bonds in protein-peptide interactions by amide-to-ester mutations

    DEFF Research Database (Denmark)

    Eildal, Jonas N N; Hultqvist, Greta; Balle, Thomas

    2013-01-01

    -protein interactions, those of the PDZ domain family involve formation of intermolecular hydrogen bonds: C-termini or internal linear motifs of proteins bind as β-strands to form an extended antiparallel β-sheet with the PDZ domain. Whereas extensive work has focused on the importance of the amino acid side chains...... of the protein ligand, the role of the backbone hydrogen bonds in the binding reaction is not known. Using amide-to-ester substitutions to perturb the backbone hydrogen-bonding pattern, we have systematically probed putative backbone hydrogen bonds between four different PDZ domains and peptides corresponding...... to natural protein ligands. Amide-to-ester mutations of the three C-terminal amides of the peptide ligand severely affected the affinity with the PDZ domain, demonstrating that hydrogen bonds contribute significantly to ligand binding (apparent changes in binding energy, ΔΔG = 1.3 to >3.8 kcal mol(-1...

  10. Multi probes measurements at the PALS Facility Research Centre during high intense laser pulse interactions with various target materials

    Directory of Open Access Journals (Sweden)

    De Marco Massimo

    2018-01-01

    Full Text Available During the interaction of high intense laser pulse with solid target, a large amount of hot electrons is produced and a giant Electromagnetic Pulse (EMP is generated due to the current flowing into the system target–target holder, as well as due to the escaping charged particles in vacuum. EMP production for different target materials is investigated inside and outside the target chamber, using monopole antenna, super wide-band microstrip antenna and Moebius antenna. The EMP consists in a fast transient magnetic field lasting hundreds of nanosecond with frequencies ranging from MHz to tens of GHz. Measurements of magnetic field and return target current in the range of kA were carried out by an inductive target probe (Cikhardt J. et al. Rev. Sci. Instrum. 85 (2014 103507.

  11. Atomic Force Microscopy Probing of Receptor–Nanoparticle Interactions for Riboflavin Receptor Targeted Gold–Dendrimer Nanocomposites

    Science.gov (United States)

    2015-01-01

    Riboflavin receptors are overexpressed in malignant cells from certain human breast and prostate cancers, and they constitute a group of potential surface markers important for cancer targeted delivery of therapeutic agents and imaging molecules. Here we report on the fabrication and atomic force microscopy (AFM) characterization of a core–shell nanocomposite consisting of a gold nanoparticle (AuNP) coated with riboflavin receptor-targeting poly(amido amine) dendrimer. We designed this nanocomposite for potential applications such as a cancer targeted imaging material based on its surface plasmon resonance properties conferred by AuNP. We employed AFM as a technique for probing the binding interaction between the nanocomposite and riboflavin binding protein (RfBP) in solution. AFM enabled precise measurement of the AuNP height distribution before (13.5 nm) and after chemisorption of riboflavin-conjugated dendrimer (AuNP–dendrimer; 20.5 nm). Binding of RfBP to the AuNP–dendrimer caused a height increase to 26.7 nm, which decreased to 22.8 nm when coincubated with riboflavin as a competitive ligand, supporting interaction of AuNP–dendrimer and its target protein. In summary, physical determination of size distribution by AFM imaging can serve as a quantitative approach to monitor and characterize the nanoscale interaction between a dendrimer-covered AuNP and target protein molecules in vitro. PMID:24571134

  12. Neocarzinostatin as a probe for DNA protection activity--molecular interaction with caffeine.

    Science.gov (United States)

    Chin, Der-Hang; Li, Huang-Hsien; Kuo, Hsiu-Maan; Chao, Pei-Dawn Lee; Liu, Chia-Wen

    2012-04-01

    Neocarzinostatin (NCS), a potent mutagen and carcinogen, consists of an enediyne prodrug and a protein carrier. It has a unique double role in that it intercalates into DNA and imposes radical-mediated damage after thiol activation. Here we employed NCS as a probe to examine the DNA-protection capability of caffeine, one of common dietary phytochemicals with potential cancer-chemopreventive activity. NCS at the nanomolar concentration range could induce significant single- and double-strand lesions in DNA, but up to 75 ± 5% of such lesions were found to be efficiently inhibited by caffeine. The percentage of inhibition was caffeine-concentration dependent, but was not sensitive to the DNA-lesion types. The well-characterized activation reactions of NCS allowed us to explore the effect of caffeine on the enediyne-generated radicals. Postactivation analyses by chromatographic and mass spectroscopic methods identified a caffeine-quenched enediyne-radical adduct, but the yield was too small to fully account for the large inhibition effect on DNA lesions. The affinity between NCS chromophore and DNA was characterized by a fluorescence-based kinetic method. The drug-DNA intercalation was hampered by caffeine, and the caffeine-induced increases in DNA-drug dissociation constant was caffeine-concentration dependent, suggesting importance of binding affinity in the protection mechanism. Caffeine has been shown to be both an effective free radical scavenger and an intercalation inhibitor. Our results demonstrated that caffeine ingeniously protected DNA against the enediyne-induced damages mainly by inhibiting DNA intercalation beforehand. The direct scavenging of the DNA-bound NCS free radicals by caffeine played only a minor role. Copyright © 2011 Wiley Periodicals, Inc.

  13. Probing the WL'WH and WR'WH interactions at LHC

    International Nuclear Information System (INIS)

    Bao Shoushan; Li Honglei; Si Zongguo; Zhou Yufeng

    2011-01-01

    Many new physics models predict the existence of TeV-scale charged gauge boson W ' together with Higgs-boson(s). We study the W ' WH interaction and explore the angular distribution of charged leptons to distinguish W R ' WH from W L ' WH in the pp→HW→bblν process at the LHC. It is found that a new type forward-backward asymmetry (A FB ) relating to the angle between the direction of the charged lepton in the W rest frame and that of the reconstructed W ' in the laboratory frame is useful to investigate the properties of W ' WH interaction. We analyze the standard model backgrounds and develop a set of cuts to highlight the signal and suppress the backgrounds at LHC. We find that A FB can reach 0.03(-0.07) for W R ' (W L ' ) production at √(S)=14 TeV.

  14. Probing into the Interaction of Nicotine and Bovine Submaxillary Mucin: NMR, Fluorescence, and FTIR Approaches

    Directory of Open Access Journals (Sweden)

    Xiaoxiang Liao

    2016-01-01

    Full Text Available Nicotine, the important component of cigarette products, may have an impact on the oral environment after inhalation. The research of interaction between nicotine and bovine submaxillary mucin (BSM contributes to understand the binding mechanism of nicotine and BSM, and the effects of nicotine on the structure and function of the mucin. NMR data demonstrated that the interaction between nicotine and BSM did exist, and it was pyrrolidyl ring of nicotine playing the major role in the binding. The quenching mechanisms of nicotine and BSM in different pH were different: for acidic environment, the quenching was dynamic; while it became static in the alkaline circumstance. Synchronous fluorescence spectra indicated that nicotine had effect on the microenvironment of the Trp rather than Tyr residue. Meanwhile, the impact of nicotine on the conformation of BSM was also confirmed by 3D fluorescence and FTIR spectra.

  15. X ray emission: a tool and a probe for laser - clusters interaction

    International Nuclear Information System (INIS)

    Prigent, Ch.

    2004-12-01

    In intense laser-cluster interaction, the experimental results show a strong energetic coupling between radiation and matter. We have measured absolute X-ray yields and charge state distributions under well control conditions as a function of physical parameters governing the interaction; namely laser intensity, pulse duration, wavelength or polarization state of the laser light, the size and the species of the clusters (Ar, Kr, Xe). We have highlighted, for the first time, an intensity threshold in the X-ray production very low (∼ 2.10 14 W/cm 2 for a pulse duration of 300 fs) which can results from an effect of the dynamical polarisation of clusters in an intense electric field. A weak dependence with the wavelength (400 nm / 800 nm) on the absolute X-ray yields has been found. Moreover, we have observed a saturation of the X-ray emission probability below a critical cluster size. (author)

  16. Where in the Cell Are You? Probing HIV-1 Host Interactions through Advanced Imaging Techniques

    Directory of Open Access Journals (Sweden)

    Brennan S. Dirk

    2016-10-01

    Full Text Available Viruses must continuously evolve to hijack the host cell machinery in order to successfully replicate and orchestrate key interactions that support their persistence. The type-1 human immunodeficiency virus (HIV-1 is a prime example of viral persistence within the host, having plagued the human population for decades. In recent years, advances in cellular imaging and molecular biology have aided the elucidation of key steps mediating the HIV-1 lifecycle and viral pathogenesis. Super-resolution imaging techniques such as stimulated emission depletion (STED and photoactivation and localization microscopy (PALM have been instrumental in studying viral assembly and release through both cell–cell transmission and cell–free viral transmission. Moreover, powerful methods such as Forster resonance energy transfer (FRET and bimolecular fluorescence complementation (BiFC have shed light on the protein-protein interactions HIV-1 engages within the host to hijack the cellular machinery. Specific advancements in live cell imaging in combination with the use of multicolor viral particles have become indispensable to unravelling the dynamic nature of these virus-host interactions. In the current review, we outline novel imaging methods that have been used to study the HIV-1 lifecycle and highlight advancements in the cell culture models developed to enhance our understanding of the HIV-1 lifecycle.

  17. Adhesive interaction measured between AFM probe and lung epithelial type II cells

    International Nuclear Information System (INIS)

    Leonenko, Zoya; Finot, Eric; Amrein, Matthias

    2007-01-01

    The toxicity of inhaled nanoparticles entering the body through the lung is thought to be initially defined by the electrostatic and adhesive interaction of the particles with lung's wall. Here, we investigated the first step of the interaction of nanoparticles with lung epithelial cells using atomic force microscope (AFM) as a force apparatus. Nanoparticles were modeled by the apex of the AFM tip and the forces of interaction between the tip and the cell analyzed over time. The adhesive force and work of adhesion strongly increased for the first 100 s of contact and then leveled out. During this time, the tip was penetrating deeply into the cell. It first crossed a stiff region of the cell and then entered a much more compliant cell region. The work of adhesion and its progression over time were not dependent on the load with which the tip was brought into contact with the cell. We conclude that the initial thermodynamic aspects and the time course of the uptake of nanoparticles by lung epithelial cells can be studied using our experimental approach. It is discussed how the potential health threat posed by nanoparticles of different size and surface characteristics can be evaluated using the method presented

  18. Probing protein interactions with hydrogen/deuterium exchange and mass spectrometry—A review

    International Nuclear Information System (INIS)

    Percy, Andrew J.; Rey, Martial; Burns, Kyle M.; Schriemer, David C.

    2012-01-01

    Highlights: ► Protein chemistry generates mass shifts useful for structure–function studies. ► H/DX supports a powerful mass shift method for protein interaction analysis. ► H/DX mass shifts are useful for determining binding data (K d , off-rates). ► Improved H/DX–MS workflows can accommodate complex protein systems. - Abstract: Assessing the functional outcome of protein interactions in structural terms is a goal of structural biology, however most techniques have a limited capacity for making structure–function determinations with both high resolution and high throughput. Mass spectrometry can be applied as a reader of protein chemistries in order to fill this void, and enable methodologies whereby protein structure–function determinations may be made on a proteome-wide level. Protein hydrogen/deuterium exchange (H/DX) offers a chemical labeling strategy suitable for tracking changes in “dynamic topography” and thus represents a powerful means of monitoring protein structure–function relationships. This review presents the exchange method in the context of interaction analysis. Applications involving interface detection, quantitation of binding, and conformational responses to ligation are discussed, and commentary on recent analytical developments is provided.

  19. Tailor-made ezrin actin binding domain to probe its interaction with actin in-vitro.

    Directory of Open Access Journals (Sweden)

    Rohini Shrivastava

    Full Text Available Ezrin, a member of the ERM (Ezrin/Radixin/Moesin protein family, is an Actin-plasma membrane linker protein mediating cellular integrity and function. In-vivo study of such interactions is a complex task due to the presence of a large number of endogenous binding partners for both Ezrin and Actin. Further, C-terminal actin binding capacity of the full length Ezrin is naturally shielded by its N-terminal, and only rendered active in the presence of Phosphatidylinositol bisphosphate (PIP2 or phosphorylation at the C-terminal threonine. Here, we demonstrate a strategy for the design, expression and purification of constructs, combining the Ezrin C-terminal actin binding domain, with functional elements such as fusion tags and fluorescence tags to facilitate purification and fluorescence microscopy based studies. For the first time, internal His tag was employed for purification of Ezrin actin binding domain based on in-silico modeling. The functionality (Ezrin-actin interaction of these constructs was successfully demonstrated by using Total Internal Reflection Fluorescence Microscopy. This design can be extended to other members of the ERM family as well.

  20. Few-Nucleon Research at TUNL: Probing Two- and Three-Nucleon Interactions with Neutrons

    Science.gov (United States)

    Howell, C. R.; Tornow, W.; Witała, H.

    2016-03-01

    The central goal of few-nucleon research at the Triangle Universities Nuclear Laboratory (TUNL) is to perform measurements that contribute to advancing ab-initio calculations of nuclear structure and reactions. The program aims include evaluating theoretical treatments of few-nucleon reaction dynamics through strategically comparing theory predictions to data, determining properties of the neutron-neutron interaction that are not accessible in two-nucleon reactions, and searching for evidence of longrange features of three-nucleon interactions, e.g., spin and isospin dependence. This paper will review studies of three- and four-nucleon systems at TUNL conducted using unpolarized and polarized neutron beams. Measurements of neutron-induced reactions performed by groups at TUNL over the last six years are described in comparison with theory predictions. The results are discussed in the context of the program goals stated above. Measurements of vector analyzing powers for elastic scattering in A=3 and A=4 systems, differential cross sections for neutron-deuteron elastic scattering and neutrondeuteron breakup in several final-state configurations are described. The findings from these studies and plans for the coming three years are presented in the context of worldwide activities in this front, in particular, research presented in this session.

  1. Probing the mechanical properties, conformational changes, and interactions of nucleic acids with magnetic tweezers.

    Science.gov (United States)

    Kriegel, Franziska; Ermann, Niklas; Lipfert, Jan

    2017-01-01

    Nucleic acids are central to the storage and transmission of genetic information. Mechanical properties, along with their sequence, both enable and fundamentally constrain the biological functions of DNA and RNA. For small deformations from the equilibrium conformations, nucleic acids are well described by an isotropic elastic rod model. However, external forces and torsional strains can induce conformational changes, giving rise to a complex force-torque phase diagram. This review focuses on magnetic tweezers as a powerful tool to precisely determine both the elastic parameters and conformational transitions of nucleic acids under external forces and torques at the single-molecule level. We review several variations of magnetic tweezers, in particular conventional magnetic tweezers, freely orbiting magnetic tweezers and magnetic torque tweezers, and discuss their characteristic capabilities. We then describe the elastic rod model for DNA and RNA and discuss conformational changes induced by mechanical stress. The focus lies on the responses to torque and twist, which are crucial in the mechanics and interactions of nucleic acids and can directly be measured using magnetic tweezers. We conclude by highlighting several recent studies of nucleic acid-protein and nucleic acid-small-molecule interactions as further applications of magnetic tweezers and give an outlook of some exciting developments to come. Copyright © 2016. Published by Elsevier Inc.

  2. Few-Nucleon Research at TUNL: Probing Two- and Three-Nucleon Interactions with Neutrons

    Directory of Open Access Journals (Sweden)

    Howell C.R.

    2016-01-01

    Full Text Available The central goal of few-nucleon research at the Triangle Universities Nuclear Laboratory (TUNL is to perform measurements that contribute to advancing ab-initio calculations of nuclear structure and reactions. The program aims include evaluating theoretical treatments of few-nucleon reaction dynamics through strategically comparing theory predictions to data, determining properties of the neutron-neutron interaction that are not accessible in two-nucleon reactions, and searching for evidence of longrange features of three-nucleon interactions, e.g., spin and isospin dependence. This paper will review studies of three- and four-nucleon systems at TUNL conducted using unpolarized and polarized neutron beams. Measurements of neutron-induced reactions performed by groups at TUNL over the last six years are described in comparison with theory predictions. The results are discussed in the context of the program goals stated above. Measurements of vector analyzing powers for elastic scattering in A=3 and A=4 systems, differential cross sections for neutron-deuteron elastic scattering and neutrondeuteron breakup in several final-state configurations are described. The findings from these studies and plans for the coming three years are presented in the context of worldwide activities in this front, in particular, research presented in this session.

  3. A probe to study the toxic interaction of tartrazine with bovine hemoglobin at the molecular level.

    Science.gov (United States)

    Li, Yating; Wei, Haoran; Liu, Rutao

    2014-03-01

    Tartrazine is an artificial azo dye commonly used in food products, but tartrazine in the environment is potentially harmful. The toxic interaction between tartrazine and bovine hemoglobin (BHb) was investigated using fluorescence, synchronous fluorescence, UV-vis absorption, circular dichroism (CD) and molecular modeling techniques under simulated physiological conditions. The fluorescence data showed that tartrazine can bind with BHb to form a complex. The binding process was a spontaneous molecular interaction, in which van der Waals' forces and hydrogen bonds played major roles. Molecular docking results showed that the hydrogen bonds exist between the oxygen atoms at position 31 of tartrazine and the nitrogen atom NZ7 on Lys99, and also between the oxygen atoms at position 15 of tartrazine and the nitrogen atom NZ7 on Lys104, Lys105. The results of UV-vis and CD spectra revealed that tartrazine led to conformational changes in BHb, including loosening of the skeleton structure and decreasing α helix in the secondary structure. The synchronous fluorescence experiment revealed that tartrazine binds into the hemoglobin central cavity, and this was verified using a molecular modeling study. Copyright © 2013 John Wiley & Sons, Ltd.

  4. Probing quantum and thermal noise in an interacting many-body system

    DEFF Research Database (Denmark)

    Hofferberth, S.; Lesanovsky, Igor; Schumm, Thorsten

    2008-01-01

    of the shot-to-shot variations of interference-fringe contrast for pairs of independently created one-dimensional Bose condensates. Analysing different system sizes, we observe the crossover from thermal to quantum noise, reflected in a characteristic change in the distribution functions from poissonian......The probabilistic character of the measurement process is one of the most puzzling and fascinating aspects of quantum mechanics. In many-body systems quantum-mechanical noise reveals non-local correlations of the underlying many-body states. Here, we provide a complete experimental analysis....... Furthermore, our experiments constitute the first analysis of the full distribution of quantum noise in an interacting many-body system....

  5. On the interactions between energetic electrons and lightning whistler waves observed at high L-shells on Van Allen Probes

    Science.gov (United States)

    Zheng, H.; Holzworth, R. H., II; Brundell, J. B.; Hospodarsky, G. B.; Jacobson, A. R.; Fennell, J. F.; Li, J.

    2017-12-01

    Lightning produces strong broadband radio waves, called "sferics", which propagate in the Earth-ionosphere waveguide and are detected thousands of kilometers away from their source. Global real-time detection of lightning strokes including their time, location and energy, is conducted with the World Wide Lightning Location Network (WWLLN). In the ionosphere, these sferics couple into very low frequency (VLF) whistler waves which propagate obliquely to the Earth's magnetic field. A good match has previously been shown between WWLLN sferics and Van Allen Probes lightning whistler waves. It is well known that lightning whistler waves can modify the distribution of energetic electrons in the Van Allen belts by pitch angle scattering into the loss cone, especially at low L-Shells (referred to as LEP - Lightning-induced Electron Precipitation). It is an open question whether lightning whistler waves play an important role at high L-shells. The possible interactions between energetic electrons and lightning whistler waves at high L-shells are considered to be weak in the past. However, lightning is copious, and weak pitch angle scattering into the drift or bounce loss cone would have a significant influence on the radiation belt populations. In this work, we will analyze the continuous burst mode EMFISIS data from September 2012 to 2016, to find out lightning whistler waves above L = 3. Based on that, MAGEIS data are used to study the related possible wave-particle interactions. In this talk, both case study and statistical analysis results will be presented.

  6. Spectral-fluorescent study of the interaction of the polymethine dye probe Cyan 2 with chondroitin-4-sulfate

    Science.gov (United States)

    Tatikolov, Alexander S.; Akimkin, Timofey M.; Panova, Ina G.; Yarmoluk, Sergiy M.

    2017-04-01

    The noncovalent interaction of the polymethine dye probe 3,3‧,9-trimethylthiacarbocyanine iodide (Cyan 2) with chondroitin-4-sulfate (C4S) in buffer solutions with different pH and in water in the absence of buffers has been studied by spectral-fluorescent methods. It has been shown that in all media studied, at relatively high concentrations, the dye is bound to C4S mainly as a monomer, which is accompanied by a steep rise of fluorescence (the intermediate formation of dye aggregates on the biopolymer is also observed). From the dependence of the fluorescence quantum yield on the concentration of C4S, the parameters of binding of the dye monomer to C4S were obtained: the effective binding constant K, the number of the monomeric C4S units n per one dye monomer bound to C4S, and the fluorescence quantum yield of the bound dye monomer Φfb. The dependence of Φfb (and K) on pH of the medium is not monotonic: it has a minimum in the region of neutral pH and a growth in the regions of acid and basic pH. This can be explained by changing the charge of a C4S macromolecule as a function of pH and related conformational alterations in the biopolymer, which can affect the rigidity of a dye molecule and the energy of its interaction with the biopolymer.

  7. Probing velocity dependent self-interacting dark matter with neutrino telescopes

    Science.gov (United States)

    Robertson, Denis S.; Albuquerque, Ivone F. M.

    2018-02-01

    Self-interacting dark matter models constitute an attractive solution to problems in structure formation on small scales. A simple realization of these models considers the dark force mediated by a light particle which can couple to the Standard Model through mixings with the photon or the Z boson. Within this scenario we investigate the sensitivity of the IceCube-DeepCore and PINGU neutrino telescopes to the associated muon neutrino flux produced by dark matter annihilations in the Sun. Despite the model's simplicity, several effects naturally appear: momentum suppressed capture by nuclei, velocity dependent dark matter self-capture, Sommerfeld enhanced annihilation, as well as the enhancement on the neutrino flux due to mediator late decays. Taking all these effects into account, we find that most of the model relevant parameter space can be tested by the three years of data already collected by the IceCube-DeepCore. We show that indirect detection through neutrinos can compete with the strong existing limits from direct detection experiments, specially in the case of isospin violation.

  8. Probing the interaction of noble gases with pristine and nitrogen-doped graphene through Raman spectroscopy

    Science.gov (United States)

    Cunha, Renato; Perea-López, Néstor; Elías, Ana Laura; Fujisawa, Kazunori; Carozo, Victor; Feng, Simin; Lv, Ruitao; dos Santos, Maria Cristina; Terrones, Mauricio; Araujo, Paulo T.

    2018-05-01

    The interactions of adsorbates with graphene have received increasing attention due to its importance in the development of applications involving graphene-based coatings. Here, we present a study of the adsorption of noble gases on pristine and nitrogen-doped graphene. Single-layer graphene samples were synthesized by chemical vapor deposition (CVD) and transferred to transmission electron microscopy (TEM) grids. Several noble gases were allowed to adsorb on the suspended graphene substrate at very low temperatures. Raman spectra show distinct frequency blue shifts in both the 2D and G bands, which are induced by gas adsorption onto high quality single layer graphene (1LG). These shifts, which we associate with compressive biaxial strain in the graphene layers induced by the noble gases, are negligible for nitrogen-doped graphene. Additionally, a thermal depinning transition, which is related to the desorption of a noble gas layer from the graphene surface at low temperatures (ranging from 20 to 35 K), was also observed at different transition temperatures for different noble gases. These transition temperatures were found to be 25 K for argon and 35 K for xenon. Moreover, we were able to obtain values for the compressive biaxial strain in graphene induced by the adsorbed layer of noble gases, using Raman spectroscopy. Ab initio calculations confirmed the correlation between the noble gas-induced strain and the changes in the Raman features observed.

  9. Probing the sign-changeable interaction between dark energy and dark matter with current observations

    Science.gov (United States)

    Guo, Juan-Juan; Zhang, Jing-Fei; Li, Yun-He; He, Dong-Ze; Zhang, Xin

    2018-03-01

    We consider the models of vacuum energy interacting with cold dark matter in this study, in which the coupling can change sigh during the cosmological evolution. We parameterize the running coupling b by the form b( a) = b 0 a+ b e(1- a), where at the early-time the coupling is given by a constant b e and today the coupling is described by another constant b 0. We explore six specific models with (i) Q = b( a) H 0 ρ 0, (ii) Q = b( a) H 0 ρ de, (iii) Q = b( a) H 0 ρ c, (iv) Q = b( a) Hρ 0, (v) Q = b( a) H ρ de, and (vi) Q = b( a) Hρ c. The current observational data sets we use to constrain the models include the JLA compilation of type Ia supernova data, the Planck 2015 distance priors data of cosmic microwave background observation, the baryon acoustic oscillations measurements, and the Hubble constant direct measurement. We find that, for all the models, we have b 0 0 at around the 1 σ level, and b 0 and b e are in extremely strong anti-correlation. Our results show that the coupling changes sign during the evolution at about the 1 σ level, i.e., the energy transfer is from dark matter to dark energy when dark matter dominates the universe and the energy transfer is from dark energy to dark matter when dark energy dominates the universe.

  10. Probing the interactions of charmed mesons with nuclei in anti p-induced reactions

    International Nuclear Information System (INIS)

    Golubeva, Ye.S.; Cassing, W.; Kondratyuk, L.A.

    2002-01-01

    We study the perspectives of resonant and nonresonant charmed-meson production in anti p+A reactions within the Multiple Scattering Monte Carlo (MSMC) approach. We calculate the production of the resonances Ψ(3770), Ψ(4040) and Ψ(4160) on various nuclei, their propagation and decay to D, anti D, D * , anti DD * , D s , anti D s in the medium and vacuum, respectively. The modifications of the open charm vector mesons in the nuclear medium are found to be rather moderate or even small such that dilepton spectroscopy will require an invariant mass resolution of a few MeV. Furthermore, the elastic and inelastic interactions of the open charm mesons in the medium are taken into account, which can be related to (u, d)-, s- or c-quark exchange with nucleons. It is found that by studying the D/ anti D ratio for low momenta in the laboratory (≤2-2.2 GeV/c) as a function of the target mass A stringent constraints on the c-quark exchange cross-section can be obtained. On the other hand, the ratios D - s /D + s as well as D/D - s and D/D + s at low momenta as a function of A will permit to fix independently the strength of the s-quark exchange reaction in D - s N scattering. (orig.)

  11. Design, synthesis and evaluation of a new fluorescent probe for measuring polymyxin-lipopolysaccharide binding interactions

    Science.gov (United States)

    Soon, Rachel L.; Velkov, Tony; Chiu, Francis; Thompson, Philip E.; Kancharla, Rashmi; Roberts, Kade; Larson, Ian; Nation, Roger L.; Li, Jian

    2011-01-01

    Fluorescence assays employing semi-synthetic or commercial dansyl-polymyxin B, have been widely employed to assess the affinity of polycations, including polymyxins, for bacterial cells and lipopolysaccharide (LPS). The five primary γ-amines on diaminobutyric-acid residues of polymyxin B are potentially derivatized with dansyl-cholride. Mass spectrometric analysis of the commercial product revealed a complex mixture of di- or tetra- dansyl-substituted polymyxin B. We synthesized a mono-substituted fluorescent derivative, dansyl[Lys]1polymyxinB3. The affinity of polymyxin for purified Gram-negative LPS, and whole bacterial cells was investigated. The affinity of dansyl[Lys]1polymyxinB3 for LPS was comparable to polymyxin B and colistin, and considerably greater (kd dansyl[Lys]1polymyxinB3 to LPS, attributed to electrostatic interactions. The hydrophobic dansyl moiety imparted a greater entropic contribution to the dansyl[Lys]1polymyxinB3-LPS reaction. Molecular modeling revealed a loss of electrostatic contact within the dansyl[Lys]1polymyxinB3-LPS complex due to steric hindrance from the dansyl[Lys]1 fluorophore; this corresponded with diminished antibacterial activity (MIC ≥ 16 μg/mL). Dansyl[Lys]1polymyxinB3 may prove useful as a screening tool for drug development. PMID:21050838

  12. Micro-rheology and interparticle interactions in aerosols probed with optical tweezers

    Science.gov (United States)

    Reid, Jonathan P.; Power, Rory M.; Cai, Chen; Simpson, Stephen H.

    2014-09-01

    Using optical tweezers for micro-rheological investigations of a surrounding fluid has been routinely demonstrated. In this work, we will demonstrate that rheological measurements of the bulk and surface properties of aerosol particles can be made directly using optical tweezers, providing important insights into the phase behavior of materials in confined environments and the rate of molecular diffusion in viscous phases. The use of holographic optical tweezers to manipulate aerosol particles has become standard practice in recent years, providing an invaluable tool to investigate particle dynamics, including evaporation/ condensation kinetics, chemical aging and phase transformation. When combined with non-linear Raman spectroscopy, the size and refractive index of a particle can be determined with unprecedented accuracy viscosity and surface tension of particles can be measured directly in the under-damped regime at low viscosity. In the over-damped regime, we will show that viscosity measurements can extend close to the glass transition, allowing measurements over an impressive dynamic range of 12 orders of magnitude in relaxation timescale and viscosity. Indeed, prior to the coalescence event, we will show how the Brownian trajectories of trapped particles can yield important and unique insights into the interactions of aerosol particles.

  13. Electroweak oblique parameters as a probe of the trilinear Higgs boson self-interaction

    DEFF Research Database (Denmark)

    Kribs, Graham D.; Maier, Andreas; Rzehak, Heidi

    2017-01-01

    We calculate the two-loop contributions from a modified trilinear Higgs self-interaction, κλλSMvh3, to the electroweak oblique parameters S and T. Using the current bounds on S and T from electroweak measurements, we find the 95% C.L. constraint on the modified trilinear coupling to be -14.0≤κλ≤17.......4. The largest effects on S and T arise from two insertions of the modified trilinear coupling that result in T/S≃-3/2; remarkably, this is nearly parallel to the axis of the tightest experimental constraint in the S-T plane. No contributions to S and T arise from a modified Higgs quartic coupling at two......-loop order. These calculations utilized a gauge-invariant parametrization of the trilinear Higgs coupling in terms of higher-dimensional operators (H†H)n with n≥3. Interestingly, the bounds on κλ that we obtain are comparable to constraints from di-Higgs production at the LHC as well as recent bounds from...

  14. Lattice QCD results on soft and hard probes of strongly interacting matter

    Science.gov (United States)

    Kaczmarek, Olaf

    2017-11-01

    We present recent results from lattice QCD relevant for the study of strongly interacting matter as it is produced in heavy ion collision experiments. The equation of state at non-vanishing density from a Taylor expansion up to 6th order will be discussed for a strangeness neutral system and using the expansion coefficients of the series limits on the critical point are estimated. Chemical freeze-out temperatures from the STAR and ALICE Collaborations will be compared to lines of constant physics calculated from the Taylor expansion of QCD bulk thermodynamic quantities. We show that qualitative features of the √{sNN} dependence of skewness and kurtosis ratios of net proton-number fluctuations measured by the STAR Collaboration can be understood from QCD results for cumulants of conserved baryon-number fluctuations. As an example for recent progress towards the determination of spectral and transport properties of the QGP from lattice QCD, we will present constraints on the thermal photon rate determined from a spectral reconstruction of continuum extrapolated lattice correlation functions in combination with input from most recent perturbative calculations.

  15. An Introduction to Drug Discovery by Probing Protein-Substrate Interactions Using Saturation Transfer Difference-Nuclear Magnetic Resonance (STD-NMR)

    Science.gov (United States)

    Guegan, Jean-Paul; Daniellou, Richard

    2012-01-01

    NMR spectroscopy is a powerful tool for characterizing and identifying molecules and nowadays is even used to characterize complex systems in biology. In the experiment presented here, students learned how to apply this modern technique to probe interactions between small molecules and proteins. With the use of simple organic synthesis, students…

  16. Probing exotic phases of interacting two-dimensional carriers using one-dimensional density modulation

    Science.gov (United States)

    Mueed, M. A.

    nature of the interacting bilayer system at nu=1 and 1/2. Finally, we focus on the half filling of a higher Landau level, namely nu=7/2, where B|| induces an anisotropic stripe phase. We show that a minute external density modulation is sufficient to cause a reorientation of the stripe phase if its wavelength is comparable to the external modulation period.

  17. Probing Interaction Between Platinum Group Metal (PGM) and Non-PGM Support Through Surface Characterization and Device Performance

    Science.gov (United States)

    Saha, Shibely

    High cost and limited abundance of Platinum (Pt) have hindered effective commercialization of Proton Exchange Membrane Fuel Cell and Electrolyzer. Efforts have been undertaken to reduce precious group metal (PGM) requirement for these devices without compromising the activity of the catalyst by using transition metal carbides (TMC) as non-PGM support thanks to their similar electronic and geometric structures as Pt. In this work Mo2C was selected as non-PGM support and Pt was used as the PGM of interest. We hypothesize that the hollow nanotube morphology of Mo2C support combined with Pt nano particles deposited on it via atomic layer deposition (ALD) technique would allow increased interaction between them which may increase the activity of Pt and Mo2C as well as maximize the Pt active surface area. Specifically, a rotary ALD equipment was used to grow Pt particles from atomic level to 2--3 nanometers by simply adjusting number of ALD cycles in order to probe the interaction between the deposited Pt nanoparticles and Mo2C nanotube support. Interaction between the Pt and Mo2 C was analyzed via surface characterization and electrochemical characterization. Interaction between Pt and Mo2C arises due to the lattice mismatch between Pt and Mo2C as well as electron migration between them. Lattice spacing analysis using high resolution transmission electron microscopy (HRTEM) images, combined with Pt binding energy shift in XPS results, clearly showed strong bonding between Pt nanoparticles and the Mo2C nanotube support in all the resultant Pt/Mo2C samples. We postulate that this strong interaction is responsible for the significantly enhanced durability observed in our constant potential electrolysis (CPE) and accelerated degradation testing (ADT). Of the three samples from different ALD cycles (15, 50 and 100), Mo2C nanotubes modified by 50 (1.07 wt% Pt loading) and 100 cycles (4.4 wt% Pt) of Pt deposition, showed higher HER and HOR activity per Pt mass than commercial

  18. Sugar-influenced water diffusion, interaction, and retention in clay interlayer nanopores probed by theoretical simulations and experimental spectroscopies

    Science.gov (United States)

    Aristilde, Ludmilla; Galdi, Stephen M.; Kelch, Sabrina E.; Aoki, Thalia G.

    2017-08-01

    Understanding the hydrodynamics in clay nanopores is important for gaining insights into the trapping of water, nutrients, and contaminants in natural and engineered soils. Previous investigations have focused on the interlayer organization and molecular diffusion coefficients (D) of cations and water molecules in cation-saturated interlayer nanopores of smectite clays. Little is known, however, about how these interlayer dynamic properties are influenced by the ubiquitous presence of small organic compounds such as sugars in the soil environment. Here we probed the effects of glucose molecules on montmorillonite interlayer properties. Molecular dynamics simulations revealed re-structuring of the interlayer organization of the adsorptive species. Water-water interactions were disrupted by glucose-water H-bonding interactions. ;Dehydration; of the glucose-populated nanopore led to depletion in the Na solvation shell, which resulted in the accumulation of both Na ions (as inner-sphere complexes) and remaining hydrated water molecules at the mineral surface. This accumulation led to a decrease in both DNa and Dwater. In addition, the reduction in Dglucose as a function of increasing glucose content can be explained by the aggregation of glucose molecules into organic clusters H-bonded to the mineral surface on both walls of the nanopore. Experimental nuclear magnetic resonance and X-ray diffraction data were consistent with the theoretical predictions. Compared to clay interlayers devoid of glucose, increased intensities and new peaks in the 23Na nuclear magnetic resonance spectra confirmed increasing immobilization of Na as a function of increasing glucose content. And, the X-ray diffraction data indicated a reduced collapse of glucose-populated interlayers exposed to decreasing moisture conditions, which led to the maintenance of hydrated clay nanopores. The coupling of theoretical and experimental findings sheds light on the molecular to nanoscale mechanisms that

  19. Probing the Selectivity and Protein•Protein Interactions of a Non-Reducing Fungal Polyketide Synthase Using Mechanism-Based Crosslinkers

    Science.gov (United States)

    Bruegger, Joel; Haushalter, Bob; Vagstad, Anna; Shakya, Gaurav; Mih, Nathan; Townsend, Craig A.; Burkart, Michael D.; Tsai, Shiou-Chuan

    2013-01-01

    SUMMARY Protein•protein interactions, which often involve interactions between an acyl carrier protein (ACP) and its partner enzymes, are important for coordinating polyketide biosynthesis. However, the nature of such interactions is not well understood, especially in the fungal non-reducing polyketide synthases (NR-PKSs) that biosynthesize toxic and pharmaceutically important polyketides. Here, we employ a mechanism-based crosslinker to successfully probe ACP and ketosynthase (KS) domain interactions in NR-PKSs. We found that crosslinking efficiency is closely correlated with the strength of ACP•KS interactions, and that KS demonstrates strong starter unit selectivity. We further identified positively charged surface residues by KS mutagenesis, which mediate key interactions with the negatively-charged ACP surface. Such complementary/matching contact pairs can serve as “adapter surfaces” for future efforts to generate new polyketides using NR-PKSs. PMID:23993461

  20. Mobile Probing and Probes

    DEFF Research Database (Denmark)

    Duvaa, Uffe; Ørngreen, Rikke; Weinkouff Mathiasen, Anne-Gitte

    2013-01-01

    Mobile probing is a method, developed for learning about digital work situations, as an approach to discover new grounds. The method can be used when there is a need to know more about users and their work with certain tasks, but where users at the same time are distributed (in time and space......). Mobile probing was inspired by the cultural probe method, and was influenced by qualitative interview and inquiry approaches. The method has been used in two subsequent projects, involving school children (young adults at 15-17 years old) and employees (adults) in a consultancy company. Findings point...... to mobile probing being a flexible method for uncovering the unknowns, as a way of getting rich data to the analysis and design phases. On the other hand it is difficult to engage users to give in depth explanations, which seem easier in synchronous dialogs (whether online or face2face). The development...

  1. Mobile Probing and Probes

    DEFF Research Database (Denmark)

    Duvaa, Uffe; Ørngreen, Rikke; Weinkouff, Anne-Gitte

    2012-01-01

    Mobile probing is a method, which has been developed for learning about digital work situations, as an approach to discover new grounds. The method can be used when there is a need to know more about users and their work with certain tasks, but where users at the same time are distributed (in time...... and space). Mobile probing was inspired by the cultural probe method, and was influenced by qualitative interview and inquiry approaches. The method has been used in two subsequent projects, involving school children (young adults at 15-17 years old) and employees (adults) in a consultancy company. Findings...... point to mobile probing being a flexible method for uncovering the unknowns, as a way of getting rich data to the analysis and design phases. On the other hand it is difficult to engage users to give in depth explanations, which seem easier in synchronous dialogs (whether online or face2face...

  2. Ultra-compact structure in radio quasars as a cosmological probe: a revised study of the interaction between cosmic dark sectors

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Xiaogang; Biesiada, Marek; Cao, Shuo; Qi, Jingzhao; Zhu, Zong-Hong, E-mail: zhengxg2012@mail.bnu.edu.cn, E-mail: marek.biesiada@us.edu.pl, E-mail: caoshuo@bnu.edu.cn, E-mail: 11132016039@bnu.edu.cn, E-mail: zhuzh@bnu.edu.cn [Department of Astronomy, Beijing Normal University, Beijing 100875 (China)

    2017-10-01

    A new compilation of 012 angular-size/redshift data for compact radio quasars from very-long-baseline interferometry (VLBI) surveys motivates us to revisit the interaction between dark energy and dark matter with these probes reaching high redshifts z ∼ 3.0. In this paper, we investigate observational constraints on different phenomenological interacting dark energy (IDE) models with the intermediate-luminosity radio quasars acting as individual standard rulers, combined with the newest BAO and CMB observation from Planck results acting as statistical rulers. The results obtained from the MCMC method and other statistical methods including figure of Merit and Information Criteria show that: (1) Compared with the current standard candle data and standard clock data, the intermediate-luminosity radio quasar standard rulers , probing much higher redshifts, could provide comparable constraints on different IDE scenarios. (2) The strong degeneracies between the interaction term and Hubble constant may contribute to alleviate the tension of H {sub 0} between the recent Planck and HST measurements. (3) Concerning the ranking of competing dark energy models, IDE with more free parameters are substantially penalized by the BIC criterion, which agrees very well with the previous results derived from other cosmological probes.

  3. Probing neutrino mass hierarchy by comparing the charged-current and neutral-current interaction rates of supernova neutrinos

    OpenAIRE

    Lai, Kwang-Chang; Lee, Fei-Fan; Lee, Feng-Shiuh; Lin, Guey-Lin; Liu, Tsung-Che; Yang, Yi

    2016-01-01

    The neutrino mass hierarchy is one of the neutrino fundamental properties yet to be determined. We introduce a method to determine neutrino mass hierarchy by comparing the interaction rate of neutral current (NC) interactions, $\

  4. Method for accurate determination of dissociation constants of optical ratiometric systems: chemical probes, genetically encoded sensors, and interacting molecules.

    Science.gov (United States)

    Pomorski, Adam; Kochańczyk, Tomasz; Miłoch, Anna; Krężel, Artur

    2013-12-03

    Ratiometric chemical probes and genetically encoded sensors are of high interest for both analytical chemists and molecular biologists. Their high sensitivity toward the target ligand and ability to obtain quantitative results without a known sensor concentration have made them a very useful tool in both in vitro and in vivo assays. Although ratiometric sensors are widely used in many applications, their successful and accurate usage depends on how they are characterized in terms of sensing target molecules. The most important feature of probes and sensors besides their optical parameters is an affinity constant toward analyzed molecules. The literature shows that different analytical approaches are used to determine the stability constants, with the ratio approach being most popular. However, oversimplification and lack of attention to detail results in inaccurate determination of stability constants, which in turn affects the results obtained using these sensors. Here, we present a new method where ratio signal is calibrated for borderline values of intensities of both wavelengths, instead of borderline ratio values that generate errors in many studies. At the same time, the equation takes into account the cooperativity factor or fluorescence artifacts and therefore can be used to characterize systems with various stoichiometries and experimental conditions. Accurate determination of stability constants is demonstrated utilizing four known optical ratiometric probes and sensors, together with a discussion regarding other, currently used methods.

  5. Vertical wind velocity measurements using a five-hole probe with remotely piloted aircraft to study aerosol-cloud interactions

    Science.gov (United States)

    Calmer, Radiance; Roberts, Gregory C.; Preissler, Jana; Sanchez, Kevin J.; Derrien, Solène; O'Dowd, Colin

    2018-05-01

    The importance of vertical wind velocities (in particular positive vertical wind velocities or updrafts) in atmospheric science has motivated the need to deploy multi-hole probes developed for manned aircraft in small remotely piloted aircraft (RPA). In atmospheric research, lightweight RPAs ( power spectral density (PSD) functions and turbulent kinetic energy (TKE) derived from the five-hole probe are compared with sonic anemometers on a meteorological mast. During a BACCHUS field campaign at Mace Head Atmospheric Research Station (Ireland), a fleet of RPAs was deployed to profile the atmosphere and complement ground-based and satellite observations of physical and chemical properties of aerosols, clouds, and meteorological state parameters. The five-hole probe was flown on straight-and-level legs to measure vertical wind velocities within clouds. The vertical velocity measurements from the RPA are validated with vertical velocities derived from a ground-based cloud radar by showing that both measurements yield model-simulated cloud droplet number concentrations within 10 %. The updraft velocity distributions illustrate distinct relationships between vertical cloud fields in different meteorological conditions.

  6. Amide I SFG Spectral Line Width Probes the Lipid-Peptide and Peptide-Peptide Interactions at Cell Membrane In Situ and in Real Time.

    Science.gov (United States)

    Zhang, Baixiong; Tan, Junjun; Li, Chuanzhao; Zhang, Jiahui; Ye, Shuji

    2018-06-13

    The balance of lipid-peptide and peptide-peptide interactions at cell membrane is essential to a large variety of cellular processes. In this study, we have experimentally demonstrated for the first time that sum frequency generation vibrational spectroscopy can be used to probe the peptide-peptide and lipid-peptide interactions in cell membrane in situ and in real time by determination of the line width of amide I band of protein backbone. Using a "benchmark" model of α-helical WALP23, it is found that the dominated lipid-peptide interaction causes a narrow line width of the amide I band, whereas the peptide-peptide interaction can markedly broaden the line width. When WALP23 molecules insert into the lipid bilayer, a quite narrow line width of the amide I band is observed because of the lipid-peptide interaction. In contrast, when the peptide lies down on the bilayer surface, the line width of amide I band becomes very broad owing to the peptide-peptide interaction. In terms of the real-time change in the line width, the transition from peptide-peptide interaction to lipid-peptide interaction is monitored during the insertion of WALP23 into 1,2-dipalmitoyl- sn-glycero-3-phospho-(1'- rac-glycerol) (DPPG) lipid bilayer. The dephasing time of a pure α-helical WALP23 in 1-palmitoyl-2-oleoyl- sn-glycero-3-phospho-(1'- rac-glycerol) and DPPG bilayer is determined to be 2.2 and 0.64 ps, respectively. The peptide-peptide interaction can largely accelerate the dephasing time.

  7. Probing neutrino mass hierarchy by comparing the charged-current and neutral-current interaction rates of supernova neutrinos

    Science.gov (United States)

    Lai, Kwang-Chang; Lee, Fei-Fan; Lee, Feng-Shiuh; Lin, Guey-Lin; Liu, Tsung-Che; Yang, Yi

    2016-07-01

    The neutrino mass hierarchy is one of the neutrino fundamental properties yet to be determined. We introduce a method to determine neutrino mass hierarchy by comparing the interaction rate of neutral current (NC) interactions, ν(bar nu) + p → ν(bar nu) + p, and inverse beta decays (IBD), bar nue + p → n + e+, of supernova neutrinos in scintillation detectors. Neutrino flavor conversions inside the supernova are sensitive to neutrino mass hierarchy. Due to Mikheyev-Smirnov-Wolfenstein effects, the full swapping of bar nue flux with the bar nux (x = μ, τ) one occurs in the inverted hierarchy, while such a swapping does not occur in the normal hierarchy. As a result, more high energy IBD events occur in the detector for the inverted hierarchy than the high energy IBD events in the normal hierarchy. By comparing IBD interaction rate with the mass hierarchy independent NC interaction rate, one can determine the neutrino mass hierarchy.

  8. Probing neutrino mass hierarchy by comparing the charged-current and neutral-current interaction rates of supernova neutrinos

    International Nuclear Information System (INIS)

    Lai, Kwang-Chang; Lee, Fei-Fan; Lee, Feng-Shiuh; Lin, Guey-Lin; Liu, Tsung-Che; Yang, Yi

    2016-01-01

    The neutrino mass hierarchy is one of the neutrino fundamental properties yet to be determined. We introduce a method to determine neutrino mass hierarchy by comparing the interaction rate of neutral current (NC) interactions, ν(ν-bar)+p→ν(ν-bar)+p, and inverse beta decays (IBD), ν-bar_e+p→n+e"+, of supernova neutrinos in scintillation detectors. Neutrino flavor conversions inside the supernova are sensitive to neutrino mass hierarchy. Due to Mikheyev-Smirnov-Wolfenstein effects, the full swapping of ν-bar_e flux with the ν-bar_x (x=μ, τ) one occurs in the inverted hierarchy, while such a swapping does not occur in the normal hierarchy. As a result, more high energy IBD events occur in the detector for the inverted hierarchy than the high energy IBD events in the normal hierarchy. By comparing IBD interaction rate with the mass hierarchy independent NC interaction rate, one can determine the neutrino mass hierarchy.

  9. Probing Interactions of N-Donor Molecules with Open Metal Sites within Paramagnetic Cr-MIL-101: A Solid-State NMR Spectroscopic and Density Functional Theory Study.

    Science.gov (United States)

    Wittmann, Thomas; Mondal, Arobendo; Tschense, Carsten B L; Wittmann, Johannes J; Klimm, Ottokar; Siegel, Renée; Corzilius, Björn; Weber, Birgit; Kaupp, Martin; Senker, Juergen

    2018-02-14

    Understanding host-guest interactions is one of the key requirements for adjusting properties in metal-organic frameworks (MOFs). In particular, systems with coordinatively unsaturated Lewis acidic metal sites feature highly selective adsorption processes. This is attributed to strong interactions with Lewis basic guest molecules. Here we show that a combination of 13 C MAS NMR spectroscopy with state-of-the-art density functional theory (DFT) calculations allows one to unravel the interactions of water, 2-aminopyridine, 3-aminopyridine, and diethylamine with the open metal sites in Cr-MIL-101. The 13 C MAS NMR spectra, obtained with ultrafast magic-angle spinning, are well resolved, with resonances distributed over 1000 ppm. They present a clear signature for each guest at the open metal sites. Based on competition experiments this leads to the following binding preference: water open metal sites, the NMR data offer additional information about the guest and framework dynamics. We expect that our strategy has the potential for probing the binding situation of adsorbate mixtures at the open metal sites of MOFs in general and thus accesses the microscopic interaction mechanisms for this important material class, which is essential for deriving structure-property relationships.

  10. Interaction between water-soluble rhodium complex RhCl(CO)(TPPTS)₂ and surfactants probed by spectroscopic methods.

    Science.gov (United States)

    Zhou, Li-Mei; Guo, Cai-Hong; Fu, Hai-Yan; Jiang, Xiao-Hui; Chen, Hua; Li, Rui-Xiang; Li, Xian-Jun

    2012-07-01

    The interactions of rhodium complex RhCl(CO)(TPPTS)(2) [TPPTS=P(m-C(6)H(4)SO(3)Na)(3)] with cationic, nonionic, and anionic surfactants have been investigated by UV-vis, fluorescence and (1)H NMR measurements. The presence of four different species of RhCl(CO)(TPPTS)(2) in cationic cetyltrimethylammonium (CTAB) solution has been demonstrated: free rhodium complex, rhodium complex bound to CTAB monomer, rhodium complex bound to CTAB premicelles, rhodium complex bound to CTAB micelles. The spectroscopy data show that RhCl(CO)(TPPTS)(2) can adsorb on the interface of cationic CTAB micelles by strong electrostatic attraction, weakly bind to the nonionic polyoxyethylene (20) sorbitan monolaurate (Tween 20) micelles by hydrophobic interaction, and does not interact with anion sodium dodecyl sulfate (SDS) micelles due to the strong electrostatic repulsion. Copyright © 2012 Elsevier B.V. All rights reserved.

  11. The $\\Xi^- +d\\to n+\\Lambda+\\Lambda$ reaction as a probe of the $\\Lambda\\Lambda$ interaction

    OpenAIRE

    Afnan, I. R.

    1997-01-01

    Within the framework of the Faddeev equations we demonstrate that a $\\Lambda\\Lambda-\\Xi N$ interaction that gives a $\\Lambda\\Lambda$ scattering length comparable to the $nn$ scattering length, and the binding energy of $^{\\ 6}_{\\Lambda\\Lambda}$He as an $\\alpha\\Lambda\\Lambda-\\alpha\\Xi N$ system, produces a final state interaction peak in the neutron spectrum for the reaction $\\Xi^- d \\to n\\Lambda\\Lambda$. This suggests that this reaction could be used to constrain the $\\Lambda\\Lambda$ scatteri...

  12. The Interaction of the Solar Wind with Solar Probe Plus - 3D Hybrid Simulation. Report 1; The Study for the Distance 4.5Rs

    Science.gov (United States)

    Lipatov, Alexander S.; Sittler, Edward C.; Hartle, Richard E.; Cooper, John F.

    2010-01-01

    Our report devotes a 3D numerical hybrid model of the interaction of the solar wind with the Solar Probe spacecraft. The Solar Probe Plus (SPP) model includes 3 main parts, namely, a non-conducting heat shield, a support system, and cylindrical section or spacecraft bus that contains the particle analysis devices and antenna. One observes an excitation of the low frequency Alfven and whistler type wave directed by the magnetic field with an amplitude of about (0.06-0.6) V/m. The compression waves and the jumps in an electric field with an amplitude of about (0.15-0.7) V/m were also observed. The wave amplitudes are comparable to or greater than previously estimated max wave amplitudes that SPP is expected to measure. The results of our hybrid simulation will be useful for understanding the plasma environment near the SPP spacecraft at the distance 4.5 Rs. Future simulation will take into account the charging of the spacecraft, the charge separation effects, an outgassing from heat shield, a photoionization and an electron impact ionization effects near the spacecraft.

  13. Probing strongly interacting electroweak dynamics through W+W-/ZZ ratios at future e+e- colliders

    International Nuclear Information System (INIS)

    Barger, V.; Cheung, K.; Han, T.; Phillips, R.J.N.

    1995-01-01

    We point out that the ratio of W + W - →W + W - and W + W - →ZZ cross sections is a sensitive probe of the dynamics of electroweak symmetry breaking, in the c.m. energy region √s WW approx-gt 1 TeV where vector boson scattering may well become strong. We suggest ways in which this ratio can be extracted at a 1.5 TeV e + e - linear collider, using W ± ,Z→jj hadronic decays and relying on dijet mass resolution to provid statistical discrimination between W ± and Z. WW fusion processes studied here are unique for exploring scalar resonances of mass of about 1 TeV and are complementary to studies via the direct channel e + e - →W + W - for the vector and nonresonant cases. With an integrated luminosity of 200 fb -1 , the signals obtained are statistically significant. A comparision with a study of the e - e - →ννW - W - process is made. Enhancements of the signal rate from using a polarized electron beam, or at a 2 TeV e + e - linear colider and possible higher energy μ + μ - colliders, are also presented

  14. Peptide nucleic acid probe for protein affinity purification based on biotin-streptavidin interaction and peptide nucleic acid strand hybridization.

    Science.gov (United States)

    Tse, Jenny; Wang, Yuanyuan; Zengeya, Thomas; Rozners, Eriks; Tan-Wilson, Anna

    2015-02-01

    We describe a new method for protein affinity purification that capitalizes on the high affinity of streptavidin for biotin but does not require dissociation of the biotin-streptavidin complex for protein retrieval. Conventional reagents place both the selectively reacting group (the "warhead") and the biotin on the same molecule. We place the warhead and the biotin on separate molecules, each linked to a short strand of peptide nucleic acid (PNA), synthetic polymers that use the same bases as DNA but attached to a backbone that is resistant to attack by proteases and nucleases. As in DNA, PNA strands with complementary base sequences hybridize. In conditions that favor PNA duplex formation, the warhead strand (carrying the tagged protein) and the biotin strand form a complex that is held onto immobilized streptavidin. As in DNA, the PNA duplex dissociates at moderately elevated temperature; therefore, retrieval of the tagged protein is accomplished by a brief exposure to heat. Using iodoacetate as the warhead, 8-base PNA strands, biotin, and streptavidin-coated magnetic beads, we demonstrate retrieval of the cysteine protease papain. We were also able to use our iodoacetyl-PNA:PNA-biotin probe for retrieval and identification of a thiol reductase and a glutathione transferase from soybean seedling cotyledons. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. Probing strongly-interacting electroweak dynamics through W+W-/ZZ ratios at future e+e- colliders

    International Nuclear Information System (INIS)

    Barger, V.

    1995-01-01

    The authors point out that the ratio of W + W - → W + W - and W + W - → ZZ cross sections is a sensitive probe of the dynamics of electroweak symmetry breaking, in the CM energy region √s ww approx-gt 1 TeV where vector boson scattering may well become strong. They suggest ways in which this ratio can be extracted at a 1.5 TeV e + e - linear collider, using W ± , Z → jj hadronic decays and relying on dijet mass resolution to provide statistical discrimination between W ± and Z. WW fusion processes studied here are unique for exploring scalar resonances of mass about 1 TeV and are complementary to studies via the direct channel e + e - → W + W - for the vector and non-resonant cases. With an integrated luminosity of 200 fb -1 , the signals obtained are statistically significant. Comparison with a study of e - e - → ννW - W - process is made. Enhancements of the signal rate from using a polarized electron beam, or at a 2 TeV e + e - linear collider and possible higher energy μ + μ - colliders, are also presented

  16. Probing nucleic acid interactions and pre-mRNA splicing by Förster resonance energy transfer (FRET) microscopy

    Czech Academy of Sciences Publication Activity Database

    Šimková, Eva; Staněk, David

    2012-01-01

    Roč. 13, č. 11 (2012), s. 14929-14945 E-ISSN 1422-0067 R&D Projects: GA AV ČR KAN200520801 Institutional support: RVO:68378050 Keywords : FRET * FLIM * acceptor photobleaching * RNA interactions * spliceosome Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.464, year: 2012

  17. Probing neutrino mass hierarchy by comparing the charged-current and neutral-current interaction rates of supernova neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Lai, Kwang-Chang [Center for General Education, Chang Gung University,Kwei-Shan, Taoyuan, 333, Taiwan (China); Leung Center for Cosmology and Particle Astrophysics (LeCosPA), National Taiwan University, Taipei, 106, Taiwan (China); Lee, Fei-Fan [Institute of Physics, National Chiao Tung University,Hsinchu, 300, Taiwan (China); Lee, Feng-Shiuh [Department of Electrophysics, National Chiao Tung University,Hsinchu, 300, Taiwan (China); Lin, Guey-Lin [Leung Center for Cosmology and Particle Astrophysics (LeCosPA), National Taiwan University, Taipei, 106, Taiwan (China); Institute of Physics, National Chiao Tung University,Hsinchu, 300, Taiwan (China); Liu, Tsung-Che [Leung Center for Cosmology and Particle Astrophysics (LeCosPA), National Taiwan University, Taipei, 106, Taiwan (China); Yang, Yi [Department of Electrophysics, National Chiao Tung University,Hsinchu, 300, Taiwan (China)

    2016-07-22

    The neutrino mass hierarchy is one of the neutrino fundamental properties yet to be determined. We introduce a method to determine neutrino mass hierarchy by comparing the interaction rate of neutral current (NC) interactions, ν(ν-bar)+p→ν(ν-bar)+p, and inverse beta decays (IBD), ν-bar{sub e}+p→n+e{sup +}, of supernova neutrinos in scintillation detectors. Neutrino flavor conversions inside the supernova are sensitive to neutrino mass hierarchy. Due to Mikheyev-Smirnov-Wolfenstein effects, the full swapping of ν-bar{sub e} flux with the ν-bar{sub x} (x=μ, τ) one occurs in the inverted hierarchy, while such a swapping does not occur in the normal hierarchy. As a result, more high energy IBD events occur in the detector for the inverted hierarchy than the high energy IBD events in the normal hierarchy. By comparing IBD interaction rate with the mass hierarchy independent NC interaction rate, one can determine the neutrino mass hierarchy.

  18. Toehold-mediated internal control to probe the near-field interaction between the metallic nanoparticle and the fluorophore

    Science.gov (United States)

    Ang, Y. S.; Yung, L. Y. L.

    2014-10-01

    Metallic nanoparticles (MNPs) are known to alter the emission of vicinal fluorophores through the near-field interaction, leading to either fluorescence quenching or enhancement. Much ambiguity remains in the experimental outcome of such a near-field interaction, particularly for bulk colloidal solution. It is hypothesized that the strong far-field interference from the inner filter effect of the MNPs could mask the true near-field MNP-fluorophore interaction significantly. Thus, in this work, a reliable internal control capable of decoupling the near-field interaction from far-field interference is established by the use of the DNA toehold concept to mediate the in situ assembly and disassembly of the MNP-fluorophore conjugate. A model gold nanoparticle (AuNP)-Cy3 system is used to investigate our proposed toehold-mediated internal control system. The maximum fluorescence enhancement is obtained for large-sized AuNP (58 nm) separated from Cy3 at an intermediate distance of 6.8 nm, while fluorescence quenching is observed for smaller-sized AuNP (11 nm and 23 nm), which is in agreement with the theoretical values reported in the literature. This work shows that the toehold-mediated internal control design can serve as a central system for evaluating the near-field interaction of other MNP-fluorophore combinations and facilitate the rational design of specific MNP-fluorophore systems for various applications.Metallic nanoparticles (MNPs) are known to alter the emission of vicinal fluorophores through the near-field interaction, leading to either fluorescence quenching or enhancement. Much ambiguity remains in the experimental outcome of such a near-field interaction, particularly for bulk colloidal solution. It is hypothesized that the strong far-field interference from the inner filter effect of the MNPs could mask the true near-field MNP-fluorophore interaction significantly. Thus, in this work, a reliable internal control capable of decoupling the near

  19. The Independent Gradient Model: A New Approach for Probing Strong and Weak Interactions in Molecules from Wave Function Calculations.

    Science.gov (United States)

    Lefebvre, Corentin; Khartabil, Hassan; Boisson, Jean-Charles; Contreras-García, Julia; Piquemal, Jean-Philip; Hénon, Eric

    2018-03-19

    Extraction of the chemical interaction signature from local descriptors based on electron density (ED) is still a fruitful field of development in chemical interpretation. In a previous work that used promolecular ED (frozen ED), the new descriptor, δg , was defined. It represents the difference between a virtual upper limit of the ED gradient (∇ρIGM , IGM=independent gradient model) that represents a noninteracting system and the true ED gradient (∇ρ ). It can be seen as a measure of electron sharing brought by ED contragradience. A compelling feature of this model is to provide an automatic workflow that extracts the signature of interactions between selected groups of atoms. As with the noncovalent interaction (NCI) approach, it provides chemists with a visual understanding of the interactions present in chemical systems. ∇ρIGM is achieved simply by using absolute values upon summing the individual gradient contributions that make up the total ED gradient. Hereby, we extend this model to relaxed ED calculated from a wave function. To this end, we formulated gradient-based partitioning (GBP) to assess the contribution of each orbital to the total ED gradient. We highlight these new possibilities across two prototypical examples of organic chemistry: the unconventional hexamethylbenzene dication, with a hexa-coordinated carbon atom, and β-thioaminoacrolein. It will be shown how a bond-by-bond picture can be obtained from a wave function, which opens the way to monitor specific interactions along reaction paths. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Study on the inclusion interaction of p-sulfonated calix[n]arenes with Vitamin K3 using methylene blue as a spectral probe.

    Science.gov (United States)

    Lu, Qin; Gu, Jiashan; Yu, Huapeng; Liu, Chun; Wang, Lun; Zhou, Yunyou

    2007-09-01

    The characteristics of host-guest complexation between p-sulfonated calix[n]arene (SCnA, n = 4, 6) and Vitamin K(3) (VK(3)) were investigated by fluorescence spectrometry and absorption spectrometry using methylene blue (MB) as a probe. Interaction with MB and SCnA led to an obvious decrease in fluorescence intensity of MB, accompanying with shifts of emission peaks. Absorption peaks also showed interesting changes; however, when VK(3) was added, fluorescence intensity and absorbance recovered and a slight and slow red shift was observed. The obtained results showed that the inclusion ability of p-sulphonated calix[n]arenes towards VK(3) was the order: p-sulphonated calix[6]arene (SC6A) >p-sulphonated calix[4]arene (SC4A). Relative mechanism was proposed to explain the inclusion process.

  1. Spectroscopic investigation on interaction and sonodynamic damage of Riboflavin to DNA under ultrasonic irradiation by using Methylene Blue as fluorescent probe

    Science.gov (United States)

    Wang, Qi; Wu, Qiong; Wang, Jun; Chen, Dandan; Fan, Ping; Wang, Baoxin

    2014-01-01

    In this paper, the Riboflavin (RF) as a sonosensitizer and Methylene Blue (MB) as a fluorescent probe were used to study the interaction and sonodynamic damage to Deoxyribonucleic Acid (DNA) by fluorescence and UV-vis spectroscopy. The results showed that the RF could efficiently bind to DNA in aqueous solution and exchange with the MB through competing reaction. And then, under ultrasonic irradiation, the RF could obviously damage the DNA. In addition, the influencing factors such as ultrasonic irradiation time and RF concentration on the sonodynamic damage to DNA were also considered. The experimental results showed that the sonodynamic damage degree increase with the increase of ultrasonic irradiation time and RF concentration. Perhaps, this paper may offer some important subjects for broadening the application of RF in sonodynamic therapy (SDT) technologies for tumor treatment.

  2. Probing the interaction of ferrocene containing hyperbranched poly-ester with model plasma protein: Effect on the interaction mechanism and conformational change

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Fengjuan, E-mail: xfj66@126.com; Gu, Muqing; Liang, Ye; Li, Lanlan; Yu, Xiaolei; Wu, Xiangfeng

    2014-05-01

    Interaction mechanism and conformational change of model plasma protein-bovine serum albumin (BSA) induced by ferrocenyl-functionalized hyperbranched polyester (HBPE-Fc) were investigated using cyclicvoltammetry (CV), differential pulsed voltammetry (DPV), fluorescence, UV–vis absorption spectrometry and circular dichroism (CD). Some complicated interactions occurred between BSA and HBPE-Fc and the new redox centers appeared in the BSA/HBPE-Fc complex that changed and hindered the electron transfer of Fe/Fe{sup 2+}. Fluorescence quenching data showed that the fluorescence of BSA was statically quenched by HBPE-Fc, which implied that ground state complex formed between BSA and HBPE-Fc. van der Waals force and hydrogen bond played major roles in the interaction of HBPE-Fc with BSA. The binding constant Ka for HBPE-Fc–protein interaction is in the order of 10{sup 6} at room temperature indicates that there is a strong interaction between HBPE-Fc and BSA. Synchronous, three-dimensional fluorescence and CD studies indicated that the interaction of BSA with HBPE-Fc induced conformational changes in BSA with overall decrease in the α-helical structure and increase in β-pleated sheet structure. The molecular model of the interaction between HBPE-Fc and BSA was also presented according to the results in this study. - Highlights: • A novel ferrocenyl-functionalized hyperbranched polymer (HBPE-Fc) with potential anticancer effects. • New redox centers appear in the BSA/HBPE-Fc complex that changed and hindered the electron transfer of Fe/Fe{sup 2+}. • BSA fluorescence was statically quenched by HBPE-Fc. • BSA/HBPE-Fc ground state complex was mainly formed by the hydrogen bonds and van der Waals force. • HBPE-Fc induced conformational changes in BSA with overall decrease in the α-helical structure and increase in β-pleated sheet structure. • The molecular model of the interaction was presented according to the results in this study.

  3. EPR of Cu(II) in sarcosine cadmium chloride: probe into dopant site - symmetry and copper-sarcosine interaction

    CERN Document Server

    Pathinettam-Padiyan, D; Murugesan, R

    2000-01-01

    The electron paramagnetic resonance spectra of Cu(II) doped sarcosine cadmium chloride single crystals have been investigated at room temperature. Experimental results reveal that the Cu(II) ion enters the lattice interstitially. The observed superhyperfine lines indicate the superposition of two sets of quintet structure with interaction of nitrogen atoms and the two isotopes of copper. The spin Hamiltonian parameters are evaluated by Schonland method and the electric field symmetry around the copper ion is rhombic. An admixture of d sub z sup 2 orbital with the d sub x sub sup 2 sub - sub y sub sup 2 ground state is observed. Evaluation of MO coefficients reveals that the in-plane interaction between copper and nitrogen is strong in this lattice.

  4. Interaction between the magnetic moments of the 3d and the 4f electrons in manganite, probed by Ga substitution

    International Nuclear Information System (INIS)

    Ling Langsheng; Zhang Lei; Tong Wei; Qu Zhe; Pi Li; Zhang Yuheng

    2012-01-01

    The substitution of Ga for Mn in manganite Nd 0.6 Dy 0.1 Sr 0.3 MnO 3 with a ferromagnetic (FM) ground state has been performed to study the influence of the Mn-sublattice magnetic ordering on the magnetic rare-earth sublattice. It is found that the substitution of Mn 3+ with Ga 3+ ions results in a sharp decrease of T C , reflecting the reduction of the double-exchange interactions strength J Mn–Mn . At the same time, a depinning effect of the rare-earth magnetic moment has been observed. This behavior unambiguously proves that the exchange interaction between Mn and rare-earth ions J Mn–R strongly influences the rare-earth magnetic ordering at temperatures below T C and stabilizes the rare-earth magnetic ground state.

  5. Probing Interactions between AuNPs/AgNPs and Giant Unilamellar Vesicles (GUVs Using Hyperspectral Dark-field Microscopy

    Directory of Open Access Journals (Sweden)

    Anupama Bhat

    2018-03-01

    Full Text Available Noble metallic nanoparticles (NPs such as gold and silver nanoparticles (AuNPs and AgNPs have been shown to exhibit anti-tumor effect in anti-angiogenesis, photothermal and radio therapeutics. On the other hand, cell membranes are critical locales for specific targeting of cancerous cells. Therefore, NP-membrane interactions need be studied at molecular level to help better understand the underlying physicochemical mechanisms for future applications in cancer nanotechnology. Herein, we report our study on the interactions between citrate stabilized colloidal AuNPs/AgNPs (10 nm in size and giant unilamellar vesicles (GUVs using hyperspectral dark-field microscopy. GUVs are large model vesicle systems well established for the study of membrane dynamics. GUVs used in this study were prepared with dimyristoyl phosphatidylcholine (DMPC and doped with cholesterol at various molar concentrations. Both imaging and spectral results support that AuNPs and AgNPs interact very differently with GUVs, i.e., AuNPs tend to integrate in between the lipid bilayer and form a uniform golden-brown crust on vesicles, whereas AgNPs are bejeweled on the vesicle surface as isolated particles or clusters with much varied configurations. The more disruptive capability of AuNPs is hypothesized to be responsible for the formation of golden brown crusts in AuNP-GUV interaction. GUVs of 20 mol% CHOL:DMPC were found to be a most economical concentration for GUVs to achieve the best integrity and the least permeability, consistent with the finding from other phase studies of lipid mixture that the liquid-ordered domains have the largest area fraction of the entire membrane at around 20 mol% of cholesterol.

  6. Probing the communication of deoxythymidine triphosphate in HIV-1 reverse transcriptase by communication maps and interaction energy studies.

    Science.gov (United States)

    Gnanasekaran, Ramachandran

    2017-11-08

    We calculate communication maps for HIV-1 Reverse Transcriptase (RT) to elucidate energy transfer pathways between deoxythymidine triphosphate (dTTP) and other parts of the protein. This approach locates energy transport channels from the dTTP to remote regions of the protein via residues and water molecules. We examine the water dynamics near the catalytic site of HIV-1 RT by molecular dynamics (MD) simulations. We find that, within the catalytic site, the relaxation of water molecules is similar to that of the hydration water molecules present in other proteins and the relaxation time scale is fast enough to transport energy and helps in communication between dTTP and other residues in the system. To quantify energy transfer, we also calculate the interaction energies of dTTP, 2Mg 2+ , doxy-guanosine nucleotide (DG22) with their surrounding residues by using the B3LYP-D3 method. The results, from classical vibrational energy diffusivity and QM interaction energy, are complementary to identify the important residues involved in the process of polymerization. The positive and negative interactions by dTTP with different types of residues in the catalytic region make the residues transfer energy through vibrational communication.

  7. Probing into the binding interaction between medroxyprogesterone acetate and bovine serum albumin (BSA): spectroscopic and molecular docking methods.

    Science.gov (United States)

    Fang, Fang; Pan, Dong-Qi; Qiu, Min-Jie; Liu, Ting-Ting; Jiang, Min; Wang, Qi; Shi, Jie-Hua

    2016-09-01

    To further understand the mechanism of action and pharmacokinetics of medroxyprogesterone acetate (MPA), the binding interaction of MPA with bovine serum albumin (BSA) under simulated physiological conditions (pH 7.4) was studied using fluorescence emission spectroscopy, synchronous fluorescence spectroscopy, circular dichroism and molecular docking methods. The experimental results reveal that the fluorescence of BSA quenches due to the formation of MPA-BSA complex. The number of binding sites (n) and the binding constant for MPA-BSA complex are ~1 and 4.6 × 10(3)  M(-1) at 310 K, respectively. However, it can be concluded that the binding process of MPA with BSA is spontaneous and the main interaction forces between MPA and BSA are van der Waals force and hydrogen bonding interaction due to the negative values of ΔG(0) , ΔH(0) and ΔS(0) in the binding process of MPA with BSA. MPA prefers binding on the hydrophobic cavity in subdomain IIIA (site II'') of BSA resulting in a slight change in the conformation of BSA, but BSA retaining the α-helix structure. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  8. Probing different regimes of strong field light-matter interaction with semiconductor quantum dots and few cavity photons

    Science.gov (United States)

    Hargart, F.; Roy-Choudhury, K.; John, T.; Portalupi, S. L.; Schneider, C.; Höfling, S.; Kamp, M.; Hughes, S.; Michler, P.

    2016-12-01

    In this work we present an extensive experimental and theoretical investigation of different regimes of strong field light-matter interaction for cavity-driven quantum dot (QD) cavity systems. The electric field enhancement inside a high-Q micropillar cavity facilitates exceptionally strong interaction with few cavity photons, enabling the simultaneous investigation for a wide range of QD-laser detuning. In case of a resonant drive, the formation of dressed states and a Mollow triplet sideband splitting of up to 45 μeV is measured for a mean cavity photon number ≤slant 1. In the asymptotic limit of the linear AC Stark effect we systematically investigate the power and detuning dependence of more than 400 QDs. Some QD-cavity systems exhibit an unexpected anomalous Stark shift, which can be explained by an extended dressed 4-level QD model. We provide a detailed analysis of the QD-cavity systems properties enabling this novel effect. The experimental results are successfully reproduced using a polaron master equation approach for the QD-cavity system, which includes the driving laser field, exciton-cavity and exciton-phonon interactions.

  9. Is Large-Scale-Structure formation a new probe of the Dark Matter interactions with Standard Model particles?

    CERN Multimedia

    CERN. Geneva

    2014-01-01

    In the last few decades, there have been extensive efforts made to discover dark matter particles through a significant experimental program based on direct and indirect detection techniques. However so far these searches remain unsuccessful, thus questioning our ability to elucidate one of the biggest challenges of modern Cosmology. In this talk I will review some of the key aspects of these techniques and present a new strategy to characterise the dark matter interactions with the visible sector without having to rely on critical assumptions.

  10. X ray emission: a tool and a probe for laser - clusters interaction; L'emission X: un outil et une sonde pour l'interaction laser - agregats

    Energy Technology Data Exchange (ETDEWEB)

    Prigent, Ch

    2004-12-01

    In intense laser-cluster interaction, the experimental results show a strong energetic coupling between radiation and matter. We have measured absolute X-ray yields and charge state distributions under well control conditions as a function of physical parameters governing the interaction; namely laser intensity, pulse duration, wavelength or polarization state of the laser light, the size and the species of the clusters (Ar, Kr, Xe). We have highlighted, for the first time, an intensity threshold in the X-ray production very low ({approx} 2.10{sup 14} W/cm{sup 2} for a pulse duration of 300 fs) which can results from an effect of the dynamical polarisation of clusters in an intense electric field. A weak dependence with the wavelength (400 nm / 800 nm) on the absolute X-ray yields has been found. Moreover, we have observed a saturation of the X-ray emission probability below a critical cluster size. (author)

  11. Angular distributions as a probe of anomalous ZZH and γZH interactions at a linear collider with polarized beams

    International Nuclear Information System (INIS)

    Rindani, Saurabh D.; Sharma, Pankaj

    2009-01-01

    We examine the contribution of general Z*ZH and γ*ZH three-point interactions arising from new physics to the Higgs production process e + e - →HZ. From Lorentz covariance, each of these vertices may be written in terms of three (complex) form factors, whose real and imaginary parts together make six independent couplings. We take into account possible longitudinal or transverse beam polarization likely to be available at a linear collider. We show how partial cross sections and angular asymmetries in suitable combinations with appropriate beam polarizations can be used to disentangle various couplings from one another. A striking result is that using transverse polarization, one of the γZH couplings, not otherwise accessible, can be determined independently of all other couplings. Transverse polarization also helps in the independent determination of a combination of two other couplings, in contrast to a combination of four accessible with unpolarized or longitudinally polarized beams. We also obtain the sensitivity of the various observables in constraining the new-physics interactions at a linear collider operating at a center-of-mass energy of 500 GeV with longitudinal or transverse polarization.

  12. Peptide-membrane interactions of arginine-tryptophan peptides probed using quartz crystal microbalance with dissipation monitoring.

    KAUST Repository

    Rydberg, Hanna A

    2014-04-18

    Membrane-active peptides include peptides that can cross cellular membranes and deliver macromolecular cargo as well as peptides that inhibit bacterial growth. Some of these peptides can act as both transporters and antibacterial agents. It is desirable to combine the knowledge from these two different fields of membrane-active peptides into design of new peptides with tailored actions, as transporters of cargo or as antibacterial substances, targeting specific membranes. We have previously shown that the position of the amino acid tryptophan in the peptide sequence of three arginine-tryptophan peptides affects their uptake and intracellular localization in live mammalian cells, as well as their ability to inhibit bacterial growth. Here, we use quartz crystal microbalance with dissipation monitoring to assess the induced changes caused by binding of the three peptides to supported model membranes composed of POPC, POPC/POPG, POPC/POPG/cholesterol or POPC/lactosyl PE. Our results indicate that the tryptophan position in the peptide sequence affects the way these peptides interact with the different model membranes and that the presence of cholesterol in particular seems to affect the membrane interaction of the peptide with an even distribution of tryptophans in the peptide sequence. These results give mechanistic insight into the function of these peptides and may aid in the design of membrane-active peptides with specified cellular targets and actions.

  13. Peptide-membrane interactions of arginine-tryptophan peptides probed using quartz crystal microbalance with dissipation monitoring.

    KAUST Repository

    Rydberg, Hanna A; Kunze, Angelika; Carlsson, Nils; Altgä rde, Noomi; Svedhem, Sofia; Nordé n, Bengt

    2014-01-01

    Membrane-active peptides include peptides that can cross cellular membranes and deliver macromolecular cargo as well as peptides that inhibit bacterial growth. Some of these peptides can act as both transporters and antibacterial agents. It is desirable to combine the knowledge from these two different fields of membrane-active peptides into design of new peptides with tailored actions, as transporters of cargo or as antibacterial substances, targeting specific membranes. We have previously shown that the position of the amino acid tryptophan in the peptide sequence of three arginine-tryptophan peptides affects their uptake and intracellular localization in live mammalian cells, as well as their ability to inhibit bacterial growth. Here, we use quartz crystal microbalance with dissipation monitoring to assess the induced changes caused by binding of the three peptides to supported model membranes composed of POPC, POPC/POPG, POPC/POPG/cholesterol or POPC/lactosyl PE. Our results indicate that the tryptophan position in the peptide sequence affects the way these peptides interact with the different model membranes and that the presence of cholesterol in particular seems to affect the membrane interaction of the peptide with an even distribution of tryptophans in the peptide sequence. These results give mechanistic insight into the function of these peptides and may aid in the design of membrane-active peptides with specified cellular targets and actions.

  14. Facet-specific interaction between methanol and TiO2 probed by sum-frequency vibrational spectroscopy.

    Science.gov (United States)

    Yang, Deheng; Li, Yadong; Liu, Xinyi; Cao, Yue; Gao, Yi; Shen, Y Ron; Liu, Wei-Tao

    2018-04-24

    The facet-specific interaction between molecules and crystalline catalysts, such as titanium dioxides (TiO 2 ), has attracted much attention due to possible facet-dependent reactivity. Using surface-sensitive sum-frequency vibrational spectroscopy, we have studied how methanol interacts with different common facets of crystalline TiO 2 , including rutile(110), (001), (100), and anatase(101), under ambient temperature and pressure. We found that methanol adsorbs predominantly in the molecular form on all of the four surfaces, while spontaneous dissociation into methoxy occurs preferentially when these surfaces become defective. Extraction of Fermi resonance coupling between stretch and bending modes of the methyl group in analyzing adsorbed methanol spectra allows determination of the methanol adsorption isotherm. The isotherms obtained for the four surfaces are nearly the same, yielding two adsorbed Gibbs free energies associated with two different adsorption configurations singled out by ab initio calculations. They are ( i ) ∼-20 kJ/mol for methanol with its oxygen attached to a low-coordinated surface titanium, and ( ii ) ∼-5 kJ/mol for methanol hydrogen-bonded to a surface oxygen and a neighboring methanol molecule. Despite similar adsorption energetics, the Fermi resonance coupling strength for adsorbed methanol appears to depend sensitively on the surface facet and coverage.

  15. Probing the interaction of human serum albumin with DPPH in the absence and presence of the eight antioxidants.

    Science.gov (United States)

    Li, Xiangrong; Chen, Dejun; Wang, Gongke; Lu, Yan

    2015-02-25

    Albumin represents a very abundant and important circulating antioxidant in plasma. DPPH radical is also called 2,2-diphenyl-1-picrylhydrazyl. It has been widely used for measuring the efficiency of antioxidants. In this paper, the ability of human serum albumin (HSA) to scavenge DPPH radical was investigated using UV-vis absorption spectra. The interaction between HSA and DPPH was investigated in the absence and presence of eight popular antioxidants using fluorescence spectroscopy. These results indicate the antioxidant activity of HSA against DPPH radical is similar to glutathione and the value of IC50 is 5.200×10(-5) mol L(-1). In addition, the fluorescence experiments indicate the quenching mechanism of HSA, by DPPH, is a static process. The quenching process of DPPH with HSA is easily affected by the eight antioxidants, however, they cannot change the quenching mechanism of DPPH with HSA. The binding of DPPH to HSA primarily takes place in subdomain IIA and exists two classes of binding sites with two different interaction behaviors. The decreased binding constants and the number of binding sites of DPPH with HSA by the introduction of the eight antioxidants may result from the competition of the eight antioxidants and DPPH binding to HSA. The binding of DPPH to HSA may induce the micro-environment of the lone Trp-214 from polar to slightly nonpolar. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Simultaneous Assessment of Transporter-Mediated Drug-Drug Interactions Using a Probe Drug Cocktail in Cynomolgus Monkey.

    Science.gov (United States)

    Kosa, Rachel E; Lazzaro, Sarah; Bi, Yi-An; Tierney, Brendan; Gates, Dana; Modi, Sweta; Costales, Chester; Rodrigues, A David; Tremaine, Larry M; Varma, Manthena V

    2018-06-07

    We aim to establish an in vivo preclinical model to enable simultaneous assessment of inhibition potential of an investigational drug on clinically relevant drug transporters, organic anion transporting polypeptide (OATP)1B, breast cancer resistance protein (BCRP), P-glycoprotein (P-gp) and organic anion transporter (OAT)3. Pharmacokinetics of substrate cocktail consisting of pitavastatin (OATP1B substrate), rosuvastatin (OATP1B/BCRP/OAT3), sulfasalazine (BCRP) and talinolol (P-gp) were obtained in cynomolgus monkey - alone or in combination with transporter inhibitors. Single dose rifampicin (30 mg/kg) significantly (pdrugs, with a marked effect on pitavastatin and rosuvastatin (AUC ratio ~21-39). Elacridar, BCRP/P-gp inhibitor, increased the AUC of sulfasalazine, talinolol, as well as rosuvastatin and pitavastatin. An OAT1/3 inhibitor (probenecid) significantly (pdrug-drug interaction risk assessment, before advancing a new molecular entity into clinical development, as well as providing mechanistic insights on transporter-mediated interactions. The American Society for Pharmacology and Experimental Therapeutics.

  17. On the Revealing Firsthand Probing of Ocean-Ice-Atmosphere Interactions off Sabrina Coast During NBP1402

    Science.gov (United States)

    Huber, B. A.; Orsi, A. H.; Zielinski, N. J.; Durkin, W. J., IV; Clark, P.; Wiederwohl, C. L.; Rosenberg, M. A.; Gwyther, D.; Greenbaum, J. S.; Lavoie, C.; Shevenell, A.; Leventer, A.; Blankenship, D. D.; Gulick, S. P. S.; Domack, E. W.

    2014-12-01

    Diverse interactions of winds, currents and ice around Antarctica dictate how, where and when the world's densest waters form and massive floating ice shelves and glaciers melt, as well as control sea surface gas exchange and primary productivity. Compelled by recent rate estimates of East Antarctic Ice Sheet mass loss, we contrast the paths and mixing histories of oceanic waters reaching the continental ice edge off the Sabrina and Adelie coasts relying on the unique set of synoptic shipboard measurements from NBP1402 (swath bathymetry, ADCP, underway CTD). Analysis of historical hydrography and sea ice concentration fields within the Mertz Polynya indicates the apparent effect of evolving ocean-ice-atmosphere interactions on the characteristics of local Shelf Water (SW) sources to current outflow of newly formed Antarctic Bottom Water (AABW). A polynya dominated water mass structure similar to that observed off the Adelie Coast before the removal of the Mertz Ice Tongue was expected to the west of the Dalton Ice Tongue (DIT). However, we found no evidence of dense SW off Sabrina Coast, which may lessen the region's preconceived influence to global meridional overturning. Present sea ice production within the eastern Dalton Polynya is overshadowed by freshwater input to relatively stable interior upper waters. The Antarctic Coastal Current (ACoC) picks up distinct meltwater contributions along the DIT western flank and in front of the Moscow University Ice Shelf (MUIS) and Totten Glacier (TG). Unlike over other highly influential margins to global sea level rise, there is no evidence of local cross-shelf inflow and mixing of warm Circumpolar Deep Water. Relatively cold thermocline waters from the continental slope enter the eastern trough off Sabrina Coast, and they are swiftly steered poleward by complex underlying topography. Meltwater export from beneath the MUIS and TG is observed at newly discovered trenches that effectively constrain sub-cavity inflow to low

  18. Perturbations in DNA structure upon interaction with porphyrins revealed by chemical probes, DNA footprinting and molecular modelling.

    Science.gov (United States)

    Ford, K G; Neidle, S

    1995-06-01

    The interactions of several porphyrins with a 74 base-pair DNA sequence have been examined by footprinting and chemical protection methods. Tetra-(4-N-methyl-(pyridyl)) porphyrin (TMPy), two of its metal complexes and tetra-(4-trimethylanilinium) porphyrin (TMAP) bind to closely similar AT-rich sequences. The three TMPy ligands produce modest changes in DNA structure and base accessibility on binding, in contrast to the large-scale conformational changes observed with TMAP. Molecular modelling studies have been performed on TMPy and TMAP bound in the AT-rich minor groove of an oligonucleotide. These have shown that significant structural change is needed to accommodate the bulky trimethyl substituent groups of TMAP, in contrast to the facile minor groove fit of TMPy.

  19. Micron-scale mapping of megagauss magnetic fields using optical polarimetry to probe hot electron transport in petawatt-class laser-solid interactions.

    Science.gov (United States)

    Chatterjee, Gourab; Singh, Prashant Kumar; Robinson, A P L; Blackman, D; Booth, N; Culfa, O; Dance, R J; Gizzi, L A; Gray, R J; Green, J S; Koester, P; Kumar, G Ravindra; Labate, L; Lad, Amit D; Lancaster, K L; Pasley, J; Woolsey, N C; Rajeev, P P

    2017-08-21

    The transport of hot, relativistic electrons produced by the interaction of an intense petawatt laser pulse with a solid has garnered interest due to its potential application in the development of innovative x-ray sources and ion-acceleration schemes. We report on spatially and temporally resolved measurements of megagauss magnetic fields at the rear of a 50-μm thick plastic target, irradiated by a multi-picosecond petawatt laser pulse at an incident intensity of ~10 20 W/cm 2 . The pump-probe polarimetric measurements with micron-scale spatial resolution reveal the dynamics of the magnetic fields generated by the hot electron distribution at the target rear. An annular magnetic field profile was observed ~5 ps after the interaction, indicating a relatively smooth hot electron distribution at the rear-side of the plastic target. This is contrary to previous time-integrated measurements, which infer that such targets will produce highly structured hot electron transport. We measured large-scale filamentation of the hot electron distribution at the target rear only at later time-scales of ~10 ps, resulting in a commensurate large-scale filamentation of the magnetic field profile. Three-dimensional hybrid simulations corroborate our experimental observations and demonstrate a beam-like hot electron transport at initial time-scales that may be attributed to the local resistivity profile at the target rear.

  20. The interaction of taurine-salicylaldehyde Schiff base copper(II) complex with DNA and the determination of DNA using the complex as a fluorescence probe

    Science.gov (United States)

    Zhang, Xiaoyan; Wang, Yong; Zhang, Qianru; Yang, Zhousheng

    2010-09-01

    The interaction of taurine-salicylaldehyde Schiff base copper(II) (Cu(TSSB) 22+) complex with DNA was explored by using UV-vis, fluorescence spectrophotometry, and voltammetry. In pH 7.4 Tris-HCl buffer solution, the binding constant of the Cu(TSSB) 22+ complex interaction with DNA was 3.49 × 10 4 L mol -1. Moreover, due to the fluorescence enhancing of Cu(TSSB) 22+ complex in the presence of DNA, a method for determination of DNA with Cu(TSSB) 22+ complex as a fluorescence probe was developed. The fluorescence spectra indicated that the maximum excitation and emission wavelength were 389 nm and 512 nm, respectively. Under optimal conditions, the calibration graphs are linear over the range of 0.03-9.03 μg mL -1 for calf thymus DNA (CT-DNA), 0.10-36 μg mL -1 for yeast DNA and 0.01-10.01 μg mL -1 for salmon DNA (SM-DNA), respectively. The corresponding detection limits are 7 ng mL -1 for CT-DNA, 3 ng mL -1 for yeast DNA and 3 ng mL -1 for SM-DNA. Using this method, DNA in synthetic samples was determined with satisfactory results.

  1. Probe Storage

    NARCIS (Netherlands)

    Gemelli, Marcellino; Abelmann, Leon; Engelen, Johannes Bernardus Charles; Khatib, M.G.; Koelmans, W.W.; Zaboronski, Olog; Campardo, Giovanni; Tiziani, Federico; Laculo, Massimo

    2011-01-01

    This chapter gives an overview of probe-based data storage research over the last three decades, encompassing all aspects of a probe recording system. Following the division found in all mechanically addressed storage systems, the different subsystems (media, read/write heads, positioning, data

  2. Cultural probes

    DEFF Research Database (Denmark)

    Madsen, Jacob Østergaard

    The aim of this study was thus to explore cultural probes (Gaver, Boucher et al. 2004), as a possible methodical approach, supporting knowledge production on situated and contextual aspects of occupation.......The aim of this study was thus to explore cultural probes (Gaver, Boucher et al. 2004), as a possible methodical approach, supporting knowledge production on situated and contextual aspects of occupation....

  3. High spatial resolution Kelvin probe force microscopy with coaxial probes

    International Nuclear Information System (INIS)

    Brown, Keith A; Westervelt, Robert M; Satzinger, Kevin J

    2012-01-01

    Kelvin probe force microscopy (KPFM) is a widely used technique to measure the local contact potential difference (CPD) between an AFM probe and the sample surface via the electrostatic force. The spatial resolution of KPFM is intrinsically limited by the long range of the electrostatic interaction, which includes contributions from the macroscopic cantilever and the conical tip. Here, we present coaxial AFM probes in which the cantilever and cone are shielded by a conducting shell, confining the tip–sample electrostatic interaction to a small region near the end of the tip. We have developed a technique to measure the true CPD despite the presence of the shell electrode. We find that the behavior of these probes agrees with an electrostatic model of the force, and we observe a factor of five improvement in spatial resolution relative to unshielded probes. Our discussion centers on KPFM, but the field confinement offered by these probes may improve any variant of electrostatic force microscopy. (paper)

  4. Ellipsometry-based combination of isothermal sorption-desorption measurement and temperature programmed desorption technique: A probe for interaction of thin polymer films with solvent vapor

    Science.gov (United States)

    Efremov, Mikhail Yu.; Nealey, Paul F.

    2018-05-01

    An environmental chamber equipped with an in situ spectroscopic ellipsometer, programmatic vapor pressure control, and variable temperature substrate holder has been designed for studying polymer coating behavior during an exposure to a solvent vapor and also for probing the residual solvent in the film afterwards. Both sorption-desorption cycle at a constant temperature and temperature programmed desorption (TPD) of the residual solvent manifest themselves as a change of the film thickness. Monitoring of ellipsometric angles of the coating allows us to determine the thickness as a function of the vapor pressure or sample temperature. The solvent vapor pressure is precisely regulated by a computer-controlled pneumatics. TPD spectra are recorded during heating of the film in an oil-free vacuum. The vapor pressure control system is described in detail. The system has been tested on 6-170 nm thick polystyrene, poly(methyl methacrylate), and poly(2-vinyl pyridine) films deposited on silicon substrates. Liquid toluene, water, ethanol, isopropanol, cyclohexane, 1,2-dichloroethane, and chlorobenzene were used to create a vapor atmosphere. Typical sorption-desorption and TPD curves are shown. The instrument achieves sub-monolayer sensitivity for adsorption studies on flat surfaces. Polymer-solvent vapor systems with strong interaction demonstrate characteristic absorption-desorption hysteresis spanning from vacuum to the glass transition pressure. Features on the TPD curves can be classified as either glass transition related film contraction or low temperature broad contraction peak. Typical absorption-desorption and TPD dependencies recorded for the 6 nm thick polystyrene film demonstrate the possibility to apply the presented technique for probing size effects in extremely thin coatings.

  5. Neutrons as a probe

    International Nuclear Information System (INIS)

    Iizumi, Masashi

    1993-01-01

    As an introduction to the symposium a brief overview will be given about the features of neutrons as a probe. First it will be pointed out that the utilization of neutrons as a probe for investigating the structural and dynamical properties of condensed matters is a benign gift eventuated from the release of atomic energy initiated by Enrico Fermi exactly half century ago. Features of neutrons as a probe are discussed in accordance with the four basic physical properties of neutrons as an elementary particle; (1) no electric charge (the interaction with matter is nuclear), (2) the mass of neutron is 1 amu, (3) spin is 1/2 and (4) neutrons have magnetic dipole moment. Overview will be given on the uniqueness of neutrons as a probe and on the variety in the way they are used in the wide research area from the pure science to the industrial applications. (author)

  6. Interaction and dynamics of ambient water adlayers on graphite probed using AFM voltage nanolithography and electrostatic force microscopy

    International Nuclear Information System (INIS)

    Gowthami, T; Raina, Gargi; Kurra, Narendra

    2014-01-01

    In this work, we report the impact of the interaction and dynamics of increasing ambient water adlayers on etch patterns on a hydrophobic highly oriented pyrolytic graphite (HOPG) surface obtained using atomic force microscopy (AFM) voltage nanolithography in contact mode by applying a positive bias to the sample. The changes in the dimensions of the etch patterns were investigated as a function of the increasing number of water adlayers present on the HOPG, which is varied by changing the time interval since HOPG cleavage. Changes in the width of the etch patterns and the surrounding water droplets were monitored with time, using intermittent-contact-mode AFM. Electrostatic force microscopy (EFM) has been employed to study the charged nature of the etch patterns and the neighboring water film with time. The width of the etch patterns made on freshly cleaved HOPG shows an increase of ∼33% over 48 h, whereas nine-day-old cleaved HOPG shows a 79% increase over the same period. No changes in the dimensions are observed while imaging in a nitrogen atmosphere soon after lithography. In ambient conditions, the EFM phase shift of the patterns shows a large change of ∼84–88% over 30 h. This study demonstrates the effect of the stored electrostatic energy of a polarized ice-like water adlayer, resulting in changes in the dimensions of the etch patterns long after lithography, whereas liquid-like water droplets do not affect the etch patterns. (paper)

  7. Solvent Dependency of the UV-Vis Spectrum of Indenoisoquinolines: Role of Keto-Oxygens as Polarity Interaction Probes

    Science.gov (United States)

    Coletta, Andrea; Castelli, Silvia; Chillemi, Giovanni; Sanna, Nico; Cushman, Mark; Pommier, Yves; Desideri, Alessandro

    2013-01-01

    Indenoisoquinolines are the most promising non-campthotecins topoisomerase IB inhibitors. We present an integrated experimental/computational investigation of the UV-Vis spectra of the IQNs parental compound (NSC314622) and two of its derivatives (NSC724998 and NSC725776) currently undergoing Phase I clinical trials. In all the three compounds a similar dependence of the relative absorption intensities at 270 nm and 290 nm on solvent polarity is found. The keto-oxygens in positions 5 and 11 of the molecular scaffold of the molecule are the principal chromophores involved in this dependence. Protic interactions on these sites are also found to give rise to absorptions at wavelength <250 nm observed in water solution, due to the stabilization of highly polarized tautomers of the molecule. These results suggest that the keto-oxygens are important polarizable groups that can act as useful interactors with the molecular receptor, providing at the same time an useful fingerprint for the monitoring of the drug binding to topoisomerase IB. PMID:24086299

  8. Strong Metal Support Interaction of Pt and Ru Nanoparticles Deposited on HOPG Probed by the H-D Exchange Reaction

    DEFF Research Database (Denmark)

    Fiordaliso, Elisabetta M.; Dahl, Søren; Chorkendorff, Ib

    2012-01-01

    The interaction between metals and support is investigated in the case of 50 Å Pt and 50 Å Ru films deposited on a HOPG substrate. The films are prepared by electron beam physical vapor deposition and annealed in UHV to temperatures up to 700 °C. The equilibrium hydrogen exchange rate between...... adsorbed and gas phase at 1 bar is measured before and after annealing. The rate is measured in the temperature range of 40–200 °C at 1 bar, by utilization of the H-D exchange reaction. Experiments are performed on fresh cleaved and sputtered HOPG, which give similar results. We find that annealing...... the films from 150 up to 700 °C increases the amount of carbon present in the films up to 95%, as derived by surface analysis, indicating the formation of a carbon layer on top of the metal films. The exchange rate decreases dramatically with increasing carbon content on the films for both metals, pointing...

  9. Probing the role of long-range interactions in the dynamics of a long-range Kitaev chain

    Science.gov (United States)

    Dutta, Anirban; Dutta, Amit

    2017-09-01

    We study the role of long-range interactions (more precisely, the long-range superconducting gap term) on the nonequilibrium dynamics considering a long-range p -wave superconducting chain in which the superconducting term decays with distance between two sites in a power-law fashion characterized by an exponent α . We show that the Kibble-Zurek scaling exponent, dictating the power-law decay of the defect density in the final state reached following a slow (in comparison to the time scale associated with the minimum gap in the spectrum of the Hamiltonian) quenching of the chemical potential μ across a quantum critical point, depends nontrivially on the exponent α as long as α 2 , we find that the exponent saturates to the corresponding well-known value of 1 /2 expected for the short-range model. Furthermore, studying the dynamical quantum phase transitions manifested in the nonanalyticities in the rate function of the return possibility I (t ) in subsequent temporal evolution following a sudden change in μ , we show the existence of a new region; in this region, we find three instants of cusp singularities in I (t ) associated with a single sector of Fisher zeros. Notably, the width of this region shrinks as α increases and vanishes in the limit α →2 , indicating that this special region is an artifact of the long-range nature of the Hamiltonian.

  10. Probing the interaction of a therapeutic flavonoid, pinostrobin with human serum albumin: multiple spectroscopic and molecular modeling investigations.

    Directory of Open Access Journals (Sweden)

    Shevin R Feroz

    Full Text Available Interaction of a pharmacologically important flavonoid, pinostrobin (PS with the major transport protein of human blood circulation, human serum albumin (HSA has been examined using a multitude of spectroscopic techniques and molecular docking studies. Analysis of the fluorescence quenching data showed a moderate binding affinity (1.03 × 10(5 M(-1 at 25°C between PS and HSA with a 1∶1 stoichiometry. Thermodynamic analysis of the binding data (ΔS = +44.06 J mol(-1 K(-1 and ΔH = -15.48 kJ mol(-1 and molecular simulation results suggested the involvement of hydrophobic and van der Waals forces, as well as hydrogen bonding in the complex formation. Both secondary and tertiary structural perturbations in HSA were observed upon PS binding, as revealed by intrinsic, synchronous, and three-dimensional fluorescence results. Far-UV circular dichroism data revealed increased thermal stability of the protein upon complexation with PS. Competitive drug displacement results suggested the binding site of PS on HSA as Sudlow's site I, located at subdomain IIA, and was well supported by the molecular modelling data.

  11. Probing the role of Skyrme interactions on the fission dynamics of the {sup 6}Li + {sup 238}U reaction

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Ishita; Kumar, Raj; Sharma, Manoj K. [Thapar University, School of Physics and Materials Science, Patiala (India)

    2017-06-15

    The performance of selected five Skyrme forces (out of a set of 240), tested by Dutra et al., is analyzed in view of fusion-fission dynamics. These forces are assumed to perform better for neutron-rich systems, so the choice of the reaction is accordingly made by opting for a neutron-rich target in {sup 6}Li + {sup 238}U reaction. This reaction is diagnosed further in reference to fusion hindrance within the dynamical approach of the cluster-decay model (DCM). In order to reduce the computational time, three Skyrme forces are figured out with the criteria that these forces cover the barrier characteristics of the remaining two forces as well. The fission cross-sections are successfully addressed at low energies for the {sup 6}Li + {sup 238}U reaction. However, at relatively higher energies, the excitation functions show theoretical suppression with respect to experimental data, which may be associated with the possible existence of incomplete fusion (ICF). For ICF, we have considered that the {sup 6}Li broke into {sup 4}He + {sup 2}H, as mentioned in the experimental work. The calculations of ICF are carried out for the {sup 4}He + {sup 238}U reaction with the selected Skyrme forces at E{sub c.m.} = 26.20 and 27.51 MeV. These forces address the data nicely for the compound nucleus (CN) as well as ICF processes. Here, the NRAPR force seems to require lesser barrier modification as compared to the other forces, therefore it can be used as an alternate choice for calculating the interaction potential. Additionally, the prediction of cross-sections at lower energies has been done with DCM using the NRAPR force. The l-dependent % barrier modification of the Skyrme forces undertaken is also worked out in reference to fusion hindrance at below barrier energies. (orig.)

  12. Probing the interaction of flower-like CdSe nanostructure particles targeted to bovine serum albumin using spectroscopic techniques

    International Nuclear Information System (INIS)

    Ju Peng; Fan Hai; Liu Tao; Cui Lin; Ai Shiyun

    2011-01-01

    The interaction between flower-like CdSe nanostructure particles (CdSe NP) and bovine serum albumin (BSA) was investigated from a spectroscopic angle under simulative physiological conditions. Under pH 7.4, CdSe NP could effectively quench the intrinsic fluorescence of BSA via static quenching. The binding constant (K A ) was 6.38, 3.27, and 1.90x10 4 M -1 at 298, 304, and 310 K, respectively and the number of binding sites was 1.20. According to the Van't Hoff equation, the thermodynamic parameters (ΔH o =-77.48 kJ mol -1 , ΔS o =-168.17 J mol -1 K -1 ) indicated that hydrogen bonds and van der Waals forces played a major role in stabilizing the BSA-CdSe complex. Besides, UV-vis and circular dichroism (CD) results showed that the addition of CdSe NP changed the secondary structure of BSA and led to a decrease in α-helix. These results suggested that BSA underwent substantial conformational changes induced by flower-like CdSe nanostructure particles. - Highlights: → Estimate the binding of flower-like CdSe NP to BSA by spectroscopic methods. → Hydrogen bonds and van der Waals forces were the major forces. →Addition of CdSe changed the micro-environmentl of BSA. → Decrease in α-helix of BSA secondary structure induced by CdSe.

  13. Probing interaction of Gram-positive and Gram-negative bacterial cells with ZnO nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Jain, Aanchal; Bhargava, Richa; Poddar, Pankaj, E-mail: p.poddar@ncl.res.in

    2013-04-01

    In the present work, the physiological effects of the ZnO nanorods on the Gram positive (Staphylococcus aureus and Bacillus subtilis) and Gram-negative (Escherichia coli and Aerobacter aerogenes) bacterial cells have been studied. The analysis of bacterial growth curves for various concentrations of ZnO nanorods indicates that Gram positive and Gram negative bacterial cells show inhibition at concentrations of ∼ 64 and ∼ 256 μg/mL respectively. The marked difference in susceptibility towards nanorods was also validated by spread plate and disk diffusion methods. In addition, the scanning electron micrographs show a clear damage to the cells via changed morphology of the cells from rod to coccoid etc. The confocal optical microscopy images of these cells also demonstrate the reduction in live cell count in the presence of ZnO nanorods. These, results clearly indicate that the antibacterial activity of ZnO nanorods is higher towards Gram positive bacterium than Gram negative bacterium which indicates that the structure of the cell wall might play a major role in the interaction with nanostructured materials and shows high sensitivity to the particle concentration. Highlights: ► Effect of ZnO nanorods on the growth cycles of four bacterial strains. ► A relation has been established between growth rate of bacteria and concentration. ► Serious damage in the morphology of bacterial cells in the presence of ZnO nanorods. ► Microscopic studies to see the time dependent effect on bacterial cells.

  14. A high sensitive ion pairing probe (the interaction of pyrenetetrasulphonate and methyl viologen): Salt and temperature dependences and applications

    Energy Technology Data Exchange (ETDEWEB)

    Santana, Jeferson [Departamento de Bioquímica e Departamento de Química, Instituto de Química, Universidade de São Paulo, SP (Brazil); Perez, Katia R. [Departamento de Biofísica, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo-SP (Brazil); Pisco, Thiago B.; Pavanelli, David D.; Briotto Filho, Décio; Rezende, Daisy [Departamento de Bioquímica e Departamento de Química, Instituto de Química, Universidade de São Paulo, SP (Brazil); Rezende Triboni, Eduardo [Universidade Nove de Julho, São Paulo, São Paulo-SP (Brazil); Chagas Alves Lima, Francisco das [Coordenação de Química, Universidade Estadual do Piauí, Teresina-PI (Brazil); Lopes Magalhães, Janildo [Departamento de Química, Centro de Ciências da Natureza, Universidade Federal do Piauí, Centro de Ciências da Natureza, Teresina, PI (Brazil); Midea Cuccovia, Iolanda [Departamento de Bioquímica e Departamento de Química, Instituto de Química, Universidade de São Paulo, SP (Brazil); and others

    2014-07-01

    The interaction between pyrenetetrasulphonate (PTS) and methyl viologen (MV{sup 2+}) leads to a 1:1 charge transfer complex (CTC) in the concentration range below mmol L{sup −1} of the ligands. Quantum mechanical calculations show the 1:1 complex having the planar moiety of PTS and the charges of the sulfonate groups stabilized by the twisted rings of the positively charged MV{sup 2+} species. The peculiar nature of PTS includes high fluorescence quantum yield (∼1), clear specular UV–vis spectra and fluorescence emission images, as well similar S{sub 2}←S{sub 0} and S{sub 3}←S{sub 0} transitions as those of S{sub 1}←S{sub 0,} all of them exhibiting well resolved vibrational structure. MV{sup 2+} has well known electron-accepting properties that favor the complexation. These features were studied as a function of salt concentration and temperature dependences allowing a detailed comprehension of static and dynamic association processes. Quantum mechanical calculations show the 1:1 stabilization of PTS/MV{sup 2+}. In addition the effect of urea on the CTC equilibrium is presented, as expected the additive acts towards the non-complexed species (solvated free ions). The fluorescence quenching of MV{sup 2+}over PTS highlights is one of the applications of this effect for giant vesicles characterization. - Highlights: • We determined the details of PTS/MV{sup 2+} 1:1 complex formation. • Ground and excited states formation is operative. • Ion pairing effects due to urea effect are shown. • Vesicle formation is illustrated by the pair.

  15. Probing the interactions of bromchlorbuterol-HCl and phenylethanolamine A with HSA by multi-spectroscopic and molecular docking technique

    International Nuclear Information System (INIS)

    Bi, Shuyun; Zhao, Tingting; Zhou, Huifeng; Wang, Yu; Li, Zhihong

    2016-01-01

    Highlights: • Molecular docking showed that BCB/PEA was bound at sub-domain IIA of HSA. • Fluorescence lifetimes indicated that the quenching was a static quenching. • CD spectra showed that BCB/PEA changed the conformation of HSA. • The competitive binding between site markers and BCB/PEA was studied. • The mutual influence on the two drugs binding HSA was studied. - Abstract: Using fluorescence quenching, fluorescence lifetime, (UV + vis) absorption, circular dichroism (CD) and molecular docking technique, the interactions of human serum albumin (HSA) with bromchlorbuterol-HCl (BCB) and phenylethanolamine A (PEA) were investigated. The quenching rate constants and binding constants for BCB/PEA with HSA were determined at T = (292.15, 302.15 and 312.15) K respectively, which were all decreased with the increase of the temperature, showing not a dynamic quenching. The fluorescence lifetime of HSA with BCB/PEA had changed little compared to that of HSA alone (τ_0), further confirming that BCB/PEA quenching of intrinsic fluorescence of HSA is a static quenching. The effects of K"+, Ca"2"+, Cu"2"+, Zn"2"+ and Fe"3"+ on the binding were studied. The analysis of the thermodynamic parameters for BCB/(PEA + HSA) showed that BCB/PEA could bind to HSA via hydrophobic force. The binding distances were determined as 2.90 and 4.11 nm for (BCB + HSA) and (PEA + HSA) based on the Förster’s non-radiative energy transfer theory (FRET). Synchronous fluorescence and CD spectra indicated that the conformation of HSA was changed by BCB/PEA. The competitive studies for the drug with site marker suggested that both BCB and PEA were bound at Sudlow’s sites I (sub-domain IIA, also known as indometacin binding site) in HSA, and the results of the study of molecular docking also leads to the same conclusion. The competitive binding experiments for the two drugs were also performed, which further indicates that PEA and BCB could share the same binding site, and PEA has a much

  16. The Antartic Ice Borehole Probe

    Science.gov (United States)

    Behar, A.; Carsey, F.; Lane, A.; Engelhardt, H.

    2000-01-01

    The Antartic Ice Borehole Probe mission is a glaciological investigation, scheduled for November 2000-2001, that will place a probe in a hot-water drilled hole in the West Antartic ice sheet. The objectives of the probe are to observe ice-bed interactions with a downward looking camera, and ice inclusions and structure, including hypothesized ice accretion, with a side-looking camera.

  17. Mobile probes

    DEFF Research Database (Denmark)

    Ørngreen, Rikke; Jørgensen, Anna Neustrup; Noesgaard, Signe Schack

    2016-01-01

    A project investigating the effectiveness of a collection of online resources for teachers' professional development used mobile probes as a data collection method. Teachers received questions and tasks on their mobile in a dialogic manner while in their everyday context as opposed...... to in an interview. This method provided valuable insight into the contextual use, i.e. how did the online resource transfer to the work practice. However, the research team also found that mobile probes may provide the scaffolding necessary for individual and peer learning at a very local (intra-school) community...... level. This paper is an initial investigation of how the mobile probes process proved to engage teachers in their efforts to improve teaching. It also highlights some of the barriers emerging when applying mobile probes as a scaffold for learning....

  18. Optical probe

    International Nuclear Information System (INIS)

    Denis, J.; Decaudin, J.M.

    1984-01-01

    The probe includes optical means of refractive index n, refracting an incident light beam from a medium with a refractive index n1>n and reflecting an incident light beam from a medium with a refractive index n2 [fr

  19. Counting probe

    International Nuclear Information System (INIS)

    Matsumoto, Haruya; Kaya, Nobuyuki; Yuasa, Kazuhiro; Hayashi, Tomoaki

    1976-01-01

    Electron counting method has been devised and experimented for the purpose of measuring electron temperature and density, the most fundamental quantities to represent plasma conditions. Electron counting is a method to count the electrons in plasma directly by equipping a probe with the secondary electron multiplier. It has three advantages of adjustable sensitivity, high sensitivity of the secondary electron multiplier, and directional property. Sensitivity adjustment is performed by changing the size of collecting hole (pin hole) on the incident front of the multiplier. The probe is usable as a direct reading thermometer of electron temperature because it requires to collect very small amount of electrons, thus it doesn't disturb the surrounding plasma, and the narrow sweep width of the probe voltage is enough. Therefore it can measure anisotropy more sensitively than a Langmuir probe, and it can be used for very low density plasma. Though many problems remain on anisotropy, computer simulation has been carried out. Also it is planned to provide a Helmholtz coil in the vacuum chamber to eliminate the effect of earth magnetic field. In practical experiments, the measurement with a Langmuir probe and an emission probe mounted to the movable structure, the comparison with the results obtained in reverse magnetic field by using a Helmholtz coil, and the measurement of ionic sound wave are scheduled. (Wakatsuki, Y.)

  20. Probing the interaction of Rh, Co and bimetallic Rh-Co nanoparticles with the CeO2 support: catalytic materials for alternative energy generation.

    Science.gov (United States)

    Varga, E; Pusztai, P; Óvári, L; Oszkó, A; Erdőhelyi, A; Papp, C; Steinrück, H-P; Kónya, Z; Kiss, J

    2015-10-28

    The interaction of CeO2-supported Rh, Co and bimetallic Rh-Co nanoparticles, which are active catalysts in hydrogen production via steam reforming of ethanol, a process related to renewable energy generation, was studied by X-ray diffraction (XRD), high resolution electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and low energy ion scattering (LEIS). Furthermore, diffuse reflectance infrared spectroscopy (DRIFTS) of adsorbed CO as a probe molecule was used to characterize the morphology of metal particles. At small loadings (0.1%), Rh is in a much dispersed state on ceria, while at higher contents (1-5%), Rh forms 2-8 nm particles. Between 473-673 K pronounced oxygen transfer from ceria to Rh is observed and at 773 K significant agglomeration of Rh occurs. On reduced ceria, XPS indicates a possible electron transfer from Rh to ceria. The formation of smaller ceria crystallites upon loading with Co was concluded from XRD and HRTEM; for 10% Co, the CeO2 particle size decreased from 27.6 to 10.7 nm. A strong dissolution of Co into ceria and a certain extent of encapsulation by ceria were deduced by XRD, XPS and LEIS. In the bimetallic system, the presence of Rh enhances the reduction of cobalt and ceria. During thermal treatments, reoxidation of Co occurs, and Rh agglomeration as well as oxygen migration from ceria to Rh are hindered in the presence of cobalt.

  1. Ionic interaction of myosin loop 2 with residues located beyond the N-terminal part of actin probed by chemical cross-linking.

    Science.gov (United States)

    Pliszka, Barbara; Martin, Brian M; Karczewska, Emilia

    2008-02-01

    To probe ionic contacts of skeletal muscle myosin with negatively charged residues located beyond the N-terminal part of actin, myosin subfragment 1 (S1) and actin split by ECP32 protease (ECP-actin) were cross-linked with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC). We have found that unmodified S1 can be cross-linked not only to the N-terminal part, but also to the C-terminal 36 kDa fragment of ECP-actin. Subsequent experiments performed on S1 cleaved by elastase or trypsin indicate that the cross-linking site in S1 is located within loop 2. This site is composed of Lys-636 and Lys-637 and can interact with negatively charged residues of the 36 kDa actin fragment, most probably with Glu-99 and Glu-100. Cross-links are formed both in the absence and presence of MgATP.P(i) analog, although the addition of nucleotide decreases the efficiency of the cross-linking reaction.

  2. Strong influence of coadsorbate interaction on CO desorption dynamics on Ru(0001) probed by ultrafast x-ray spectroscopy and ab initio simulations

    Energy Technology Data Exchange (ETDEWEB)

    Xin, H. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Stanford Univ., Stanford, CA (United States); LaRue, J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Oberg, H. [Stockholm Univ., Stockholm (Sweden); Beye, M. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Helmholtz Zentrum Berlin fur Materialien und Energie GmbH, Berlin (Germany); Dell' Angela, M. [Univ. of Hamburg and Center for Free Electron Laser Science, Hamburg (Germany); Turner, J. J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Gladh, J. [Stockholm Univ., Stockholm (Sweden); Ng, M. L. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Sellberg, J. A. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Helmholtz Zentrum Berlin fur Materialien und Energie GmbH, Berlin (Germany); Kaya, S. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Mercurio, G. [Univ. of Hamburg and Center for Free Electron Laser Science, Hamburg (Germany); Hieke, F. [Univ. of Hamburg and Center for Free Electron Laser Science, Hamburg (Germany); Nordlund, D. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Schlotter, W. F. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Dakovski, G. L. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Minitti, M. P. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Fohlisch, A. [Helmholtz Zentrum Berlin fur Materialien und Energie GmbH, Berlin (Germany); Univ. Potsdam, Potsdam (Germany); Wolf, M. [Fritz-Haber Institute of the Max-Planck-Society, Berlin (Germany); Wurth, W. [Univ. of Hamburg and Center for Free Electron Laser Science, Hamburg (Germany); DESY Photon Science, Hamburg (Germany); Ogasawara, H. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Norskov, J. K. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Stanford Univ., Stanford, CA (United States); Ostrom, H. [Stockholm Univ., Stockholm (Sweden); Pettersson, L. G. M. [Stockholm Univ., Stockholm (Sweden); Nilsson, A. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Stockholm Univ., Stockholm (Sweden); Ablid-Pedersen, F. [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-04-16

    We show that coadsorbed oxygen atoms have a dramatic influence on the CO desorption dynamics from Ru(0001). In contrast to the precursor-mediated desorption mechanism on Ru(0001), the presence of surface oxygen modifies the electronic structure of Ru atoms such that CO desorption occurs predominantly via the direct pathway. This phenomenon is directly observed in an ultrafast pump-probe experiment using a soft x-ray free-electron laser to monitor the dynamic evolution of the valence electronic structure of the surface species. This is supported with the potential of mean force along the CO desorption path obtained from density-functional theory calculations. Charge density distribution and frozen-orbital analysis suggest that the oxygen-induced reduction of the Pauli repulsion, and consequent increase of the dative interaction between the CO 5σ and the charged Ru atom, is the electronic origin of the distinct desorption dynamics. Ab initio molecular dynamics simulations of CO desorption from Ru(0001) and oxygen-coadsorbed Ru(0001) provide further insights into the surface bond-breaking process.

  3. Thermodynamics of poly(7-methoxy-2-acetylbenzofurane methyl methacrylate-co-styrene) and poly(2-acetylbenzofurane methyl methacrylate-co-styrene)-probe interactions at different temperatures by inverse gas chromatography

    International Nuclear Information System (INIS)

    İlter, Zülfiye; Demir, Abdullah; Kaya, İsmet

    2016-01-01

    Highlights: • Thermodynamic of methacrylate-co-styrene polymers were studied by the inverse gas chromatography. • The sorption parameters of polymer-solute systems were determined under glass transition temperature of polymers. • The solubility parameter (δ 2 ) of the polymer was obtained from the slope and intercepts. • Flory-Huggins interaction parameter (χ 12 ∞ ) were determined for polymer-solute systems. - Abstract: In this study, some thermodynamic properties of poly(7-methoxy-2-acetylbenzofurane methyl methacrylate-co-styrene) Poly(MABMM-co-St) and poly(2-acetylbenzofurane methyl methacrylate-co-styrene) Poly(ABMM-co-St) were studied by the inverse gas chromatography (IGC) technique. The retention times (t r ) of selected organic probes were determined from the interactions with Poly(MABMM-co-St) and Poly(ABMM-co-St) of four groups of solvents with different chemical natures and polarities. Then, specific volume (V g 0 ) values of probes were calculated at different column temperatures. The glass transition temperatures (T g ) of Poly(MABMM-co-St) and Poly(ABMM-co-St) were found as 393, 413 K from inverse gas chromatography measurements, respectively. Under the glass transition temperatures adsorption heat (ΔH a ) and above the glass transition molar heat (ΔH 1 S ), free energies (ΔG 1 S ) and entropies (ΔS 1 S ) belonging to sorption for every probe were calculated from inverse gas chromatography measurements. The partial molar heat (ΔH 1 ∞ ), partial molar free energy (ΔG 1 ∞ ), Flory-Huggins interaction parameter (χ 12 ∞ ) and weight fraction activity coefficient (a 1 /w 1 ) ∞ , values for infinite dilute solutions were calculated for polymer-probe systems. The solubility parameter (δ 2 ) of the polymer was obtained from the slope and intercepts of Flory-Huggins interaction parameter (χ 12 ∞ ) graphs with solubility parameters (δ 1 ) of probes.

  4. DNA probes

    International Nuclear Information System (INIS)

    Castelino, J.

    1992-01-01

    The creation of DNA probes for detection of specific nucleotide segments differs from ligand detection in that it is a chemical rather than an immunological reaction. Complementary DNA or RNA is used in place of the antibody and is labelled with 32 P. So far, DNA probes have been successfully employed in the diagnosis of inherited disorders, infectious diseases, and for identification of human oncogenes. The latest approach to the diagnosis of communicable and parasitic infections is based on the use of deoxyribonucleic acid (DNA) probes. The genetic information of all cells is encoded by DNA and DNA probe approach to identification of pathogens is unique because the focus of the method is the nucleic acid content of the organism rather than the products that the nucleic acid encodes. Since every properly classified species has some unique nucleotide sequences that distinguish it from every other species, each organism's genetic composition is in essence a finger print that can be used for its identification. In addition to this specificity, DNA probes offer other advantages in that pathogens may be identified directly in clinical specimens

  5. DNA probes

    Energy Technology Data Exchange (ETDEWEB)

    Castelino, J

    1993-12-31

    The creation of DNA probes for detection of specific nucleotide segments differs from ligand detection in that it is a chemical rather than an immunological reaction. Complementary DNA or RNA is used in place of the antibody and is labelled with {sup 32}P. So far, DNA probes have been successfully employed in the diagnosis of inherited disorders, infectious diseases, and for identification of human oncogenes. The latest approach to the diagnosis of communicable and parasitic infections is based on the use of deoxyribonucleic acid (DNA) probes. The genetic information of all cells is encoded by DNA and DNA probe approach to identification of pathogens is unique because the focus of the method is the nucleic acid content of the organism rather than the products that the nucleic acid encodes. Since every properly classified species has some unique nucleotide sequences that distinguish it from every other species, each organism`s genetic composition is in essence a finger print that can be used for its identification. In addition to this specificity, DNA probes offer other advantages in that pathogens may be identified directly in clinical specimens 10 figs, 2 tabs

  6. Probing the nanoscale interaction forces and elastic properties of organic and inorganic materials using force-distance (F-D) spectroscopy

    Science.gov (United States)

    Vincent, Abhilash

    Due to their therapeutic applications such as radical scavenging, MRI contrast imaging, Photoluminescence imaging, drug delivery, etc., nanoparticles (NPs) have a significant importance in bio-nanotechnology. The reason that prevents the utilizing NPs for drug delivery in medical field is mostly due to their biocompatibility issues (incompatibility can lead to toxicity and cell death). Changes in the surface conditions of NPs often lead to NP cytotoxicity. Investigating the role of NP surface properties (surface charges and surface chemistry) on their interactions with biomolecules (Cells, protein and DNA) could enhance the current understanding of NP cytotoxicity. Hence, it is highly beneficial to the nanotechnology community to bring more attention towards the enhancement of surface properties of NPs to make them more biocompatible and less toxic to biological systems. Surface functionalization of NPs using specific ligand biomolecules have shown to enhance the protein adsorption and cellular uptake through more favorable interaction pathways. Cerium oxide NPs (CNPs also known as nanoceria) are potential antioxidants in cell culture models and understanding the nature of interaction between cerium oxide NPs and biological proteins and cells are important due to their therapeutic application (especially in site specific drug delivery systems). The surface charges and surface chemistry of CNPs play a major role in protein adsorption and cellular uptake. Hence, by tuning the surface charges and by selecting proper functional molecules on the surface, CNPs exhibiting strong adhesion to biological materials can be prepared. By probing the nanoscale interaction forces acting between CNPs and protein molecules using Atomic Force Microscopy (AFM) based force-distance (F-D) spectroscopy, the mechanism of CNP-protein adsorption and CNP cellular uptake can be understood more quantitatively. The work presented in this dissertation is based on the application of AFM in

  7. Conductivity Probe

    Science.gov (United States)

    2008-01-01

    The Thermal and Electrical Conductivity Probe (TECP) for NASA's Phoenix Mars Lander took measurements in Martian soil and in the air. The needles on the end of the instrument were inserted into the Martian soil, allowing TECP to measure the propagation of both thermal and electrical energy. TECP also measured the humidity in the surrounding air. The needles on the probe are 15 millimeters (0.6 inch) long. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  8. Probe specificity

    International Nuclear Information System (INIS)

    Laget, J.M.

    1986-11-01

    Specificity and complementarity of hadron and electron probes must be systematically developed to answer three questions currently asked in intermediate energy nuclear physics: what is nucleus structure at short distances, what is nature of short range correlations, what is three body force nature [fr

  9. The Interstellar Mapping and Acceleration Probe - A Mission to Discover the Origin of Particle Acceleration and its Fundamental Connection to the Global Interstellar Interaction

    Science.gov (United States)

    Schwadron, N.

    2017-12-01

    Our piece of cosmic real-estate, the heliosphere, is the domain of all human existence - an astrophysical case-history of the successful evolution of life in a habitable system. The Interstellar Boundary Explorer (IBEX) was the first mission to explore the global heliosphere and in concert with Voyager 1 and Voyager 2 is discovering a fundamentally new and uncharted physical domain of the outer heliosphere. In parallel, Cassini/INCA maps the global heliosphere at energies ( 5-55 keV) above those measured by IBEX. The enigmatic IBEX ribbon and the INCA belt were unanticipated discoveries demonstrating that much of what we know or think we understand about the outer heliosphere needs to be revised. The global structure of the heliosphere is highly complex and influenced by competing factors ranging from the local interstellar magnetic field, suprathermal populations both within and beyond the heliopause, and the detailed flow properties of the LISM. Global heliospheric structure and microphysics in turn influences the acceleration of energetic particles and creates feedbacks that modify the interstellar interaction as a whole. The next quantum leap enabled by IMAP will open new windows on the frontier of Heliophysics and probe the acceleration of suprathermal and higher energy particles at a time when the space environment is rapidly evolving. IMAP ultimately connects the acceleration processes observed directly at 1 AU with unprecedented sensitivity and temporal resolution with the global structure of our heliosphere. The remarkable synergy between IMAP, Voyager 1 and Voyager 2 will remain for at least the next decade as Voyager 1 pushes further into the interstellar domain and Voyager 2 moves through the heliosheath. IMAP, like ACE before it, will be a keystone of the Heliophysics System Observatory by providing comprehensive energetic particle, pickup ion, suprathermal ion, neutral atom, solar wind, solar wind heavy ion, and magnetic field observations to diagnose

  10. Far Western: probing membranes.

    Science.gov (United States)

    Einarson, Margret B; Pugacheva, Elena N; Orlinick, Jason R

    2007-08-01

    INTRODUCTIONThe far-Western technique described in this protocol is fundamentally similar to Western blotting. In Western blots, an antibody is used to detect a query protein on a membrane. In contrast, in a far-Western blot (also known as an overlay assay) the antibody is replaced by a recombinant GST fusion protein (produced and purified from bacteria), and the assay detects the interaction of this protein with target proteins on a membrane. The membranes are washed and blocked, incubated with probe protein, washed again, and subjected to autoradiography. The GST fusion (probe) proteins are often labeled with (32)P; alternatively, the membrane can be probed with unlabeled GST fusion protein, followed by detection using commercially available GST antibodies. The nonradioactive approach is substantially more expensive (due to the purchase of antibody and detection reagents) than using radioactively labeled proteins. In addition, care must be taken to control for nonspecific interactions with GST alone and a signal resulting from antibody cross-reactivity. In some instances, proteins on the membrane are not able to interact after transfer. This may be due to improper folding, particularly in the case of proteins expressed from a phage expression library. This protocol describes a way to overcome this by washing the membrane in denaturation buffer, which is then serially diluted to permit slow renaturation of the proteins.

  11. Full information acquisition in scanning probe microscopy and spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Jesse, Stephen; Belianinov, Alex; Kalinin, Sergei V.; Somnath, Suhas

    2017-04-04

    Apparatus and methods are described for scanning probe microscopy and spectroscopy based on acquisition of full probe response. The full probe response contains valuable information about the probe-sample interaction that is lost in traditional scanning probe microscopy and spectroscopy methods. The full probe response is analyzed post data acquisition using fast Fourier transform and adaptive filtering, as well as multivariate analysis. The full response data is further compressed to retain only statistically significant components before being permanently stored.

  12. Mobile Probes in Mobile Learning

    DEFF Research Database (Denmark)

    Ørngreen, Rikke; Blomhøj, Ulla; Duvaa, Uffe

    In this paper experiences from using mobile probes in educational design of a mobile learning application is presented. The probing process stems from the cultural probe method, and was influenced by qualitative interview and inquiry approaches. In the project, the mobile phone was not only acting...... as an agent for acquiring empirical data (as the situation in hitherto mobile probe settings) but was also the technological medium for which data should say something about (mobile learning). Consequently, not only the content of the data but also the ways in which data was delivered and handled, provided...... a valuable dimension for investigating mobile use. The data was collected at the same time as design activities took place and the collective data was analysed based on user experience goals and cognitive processes from interaction design and mobile learning. The mobile probe increased the knowledge base...

  13. Effect of the interaction conditions of the probe of an atomic-force microscope with the n-GaAs surface on the triboelectrization phenomenon

    Energy Technology Data Exchange (ETDEWEB)

    Baklanov, A. V., E-mail: baklanov@mail.ioffe.ru [St. Petersburg State Polytechnical University, Institute of Physics, Nanotechnology, and Telecommunications (Russian Federation); Gutkin, A. A.; Kalyuzhnyy, N. A. [Russian Academy of Sciences, Ioffe Institute (Russian Federation); Brunkov, P. N. [St. Petersburg State Polytechnical University, Institute of Physics, Nanotechnology, and Telecommunications (Russian Federation)

    2015-08-15

    Triboelectrization as a result of the scanning of an atomic-force-microscope probe over an n-GaAs surface in the contact mode is investigated. The dependences of the local potential variation on the scanning rate and the pressing force of the probe are obtained. The results are explained by point-defect formation in the surface layers of samples under the effect of deformation of these layers during probe scanning. The charge localized at these defects in the case of equilibrium changes the potential of surface, which is subject to triboelectrization. It is shown that, for qualitative explanation of the observed dependences, it is necessary to take into account both the generation and annihilation of defects in the region experiencing deformation.

  14. NASA's interstellar probe mission

    International Nuclear Information System (INIS)

    Liewer, P.C.; Ayon, J.A.; Wallace, R.A.; Mewaldt, R.A.

    2000-01-01

    NASA's Interstellar Probe will be the first spacecraft designed to explore the nearby interstellar medium and its interaction with our solar system. As envisioned by NASA's Interstellar Probe Science and Technology Definition Team, the spacecraft will be propelled by a solar sail to reach >200 AU in 15 years. Interstellar Probe will investigate how the Sun interacts with its environment and will directly measure the properties and composition of the dust, neutrals and plasma of the local interstellar material which surrounds the solar system. In the mission concept developed in the spring of 1999, a 400-m diameter solar sail accelerates the spacecraft to ∼15 AU/year, roughly 5 times the speed of Voyager 1 and 2. The sail is used to first bring the spacecraft to ∼0.25 AU to increase the radiation pressure before heading out in the interstellar upwind direction. After jettisoning the sail at ∼5 AU, the spacecraft coasts to 200-400 AU, exploring the Kuiper Belt, the boundaries of the heliosphere, and the nearby interstellar medium

  15. Probing Protein Structure and Folding in the Gas Phase by Electron Capture Dissociation

    Science.gov (United States)

    Schennach, Moritz; Breuker, Kathrin

    2015-07-01

    The established methods for the study of atom-detailed protein structure in the condensed phases, X-ray crystallography and nuclear magnetic resonance spectroscopy, have recently been complemented by new techniques by which nearly or fully desolvated protein structures are probed in gas-phase experiments. Electron capture dissociation (ECD) is unique among these as it provides residue-specific, although indirect, structural information. In this Critical Insight article, we discuss the development of ECD for the structural probing of gaseous protein ions, its potential, and limitations.

  16. Atomic quantum superposition state generation via optical probing

    DEFF Research Database (Denmark)

    Nielsen, Anne E. B.; Poulsen, Uffe Vestergaard; Negretti, Antonio

    2009-01-01

    investigate cavity enhanced probing with continuous beams of both coherent and squeezed light. The stochastic master equations used in the analysis are expressed in terms of the Hamiltonian of the probed system and the interaction between the probed system and the probe field and are thus quite generally...

  17. Residue-specific membrane location of peptides and proteins using specifically and extensively deuterated lipids and {sup 13}C-{sup 2}H rotational-echo double-resonance solid-state NMR

    Energy Technology Data Exchange (ETDEWEB)

    Xie Li; Ghosh, Ujjayini; Schmick, Scott D.; Weliky, David P., E-mail: weliky@chemistry.msu.edu [Michigan State University, Department of Chemistry (United States)

    2013-01-15

    Residue-specific location of peptides in the hydrophobic core of membranes was examined using {sup 13}C-{sup 2}H REDOR and samples in which the lipids were selectively deuterated. The transmembrane topology of the KALP peptide was validated with this approach with substantial dephasing observed for deuteration in the bilayer center and reduced or no dephasing for deuteration closer to the headgroups. Insertion of {beta} sheet HIV and helical and {beta} sheet influenza virus fusion peptides into the hydrophobic core of the membrane was validated in samples with extensively deuterated lipids.

  18. Probing lipid membrane electrostatics

    Science.gov (United States)

    Yang, Yi

    The electrostatic properties of lipid bilayer membranes play a significant role in many biological processes. Atomic force microscopy (AFM) is highly sensitive to membrane surface potential in electrolyte solutions. With fully characterized probe tips, AFM can perform quantitative electrostatic analysis of lipid membranes. Electrostatic interactions between Silicon nitride probes and supported zwitterionic dioleoylphosphatidylcholine (DOPC) bilayer with a variable fraction of anionic dioleoylphosphatidylserine (DOPS) were measured by AFM. Classical Gouy-Chapman theory was used to model the membrane electrostatics. The nonlinear Poisson-Boltzmann equation was numerically solved with finite element method to provide the potential distribution around the AFM tips. Theoretical tip-sample electrostatic interactions were calculated with the surface integral of both Maxwell and osmotic stress tensors on tip surface. The measured forces were interpreted with theoretical forces and the resulting surface charge densities of the membrane surfaces were in quantitative agreement with the Gouy-Chapman-Stern model of membrane charge regulation. It was demonstrated that the AFM can quantitatively detect membrane surface potential at a separation of several screening lengths, and that the AFM probe only perturbs the membrane surface potential by external field created by the internai membrane dipole moment. The analysis yields a dipole moment of 1.5 Debye per lipid with a dipole potential of +275 mV for supported DOPC membranes. This new ability to quantitatively measure the membrane dipole density in a noninvasive manner will be useful in identifying the biological effects of the dipole potential. Finally, heterogeneous model membranes were studied with fluid electric force microscopy (FEFM). Electrostatic mapping was demonstrated with 50 nm resolution. The capabilities of quantitative electrostatic measurement and lateral charge density mapping make AFM a unique and powerful

  19. A Rotational BODIPY Nucleotide: An Environment-Sensitive Fluorescence-Lifetime Probe for DNA Interactions and Applications in Live-Cell Microscopy

    Czech Academy of Sciences Publication Activity Database

    Dziuba, Dmytro; Jurkiewicz, Piotr; Cebecauer, Marek; Hof, Martin; Hocek, Michal

    2016-01-01

    Roč. 55, č. 1 (2016), s. 174-178 ISSN 1433-7851 R&D Projects: GA ČR GBP206/12/G151; GA ČR(CZ) GC14-03141J Institutional support: RVO:61388963 ; RVO:61388955 Keywords : DNA * fluorescence spectroscopy * fluorescent probes * nucleosides * time-resolved spectroscopy Subject RIV: CC - Organic Chemistry ; BO - Biophysics (UFCH-W) Impact factor: 11.994, year: 2016

  20. Intracellular Biosynthesis of Fluorescent CdSe Quantum Dots in Bacillus subtilis: A Strategy to Construct Signaling Bacterial Probes for Visually Detecting Interaction Between Bacillus subtilis and Staphylococcus aureus.

    Science.gov (United States)

    Yan, Zheng-Yu; Ai, Xiao-Xia; Su, Yi-Long; Liu, Xin-Ying; Shan, Xiao-Hui; Wu, Sheng-Mei

    2016-02-01

    In this work, fluorescent Bacillus subtilis (B. subtilis) cells were developed as probes for imaging applications and to explore behaviorial interaction between B. subtilis and Staphylococcus aureus (S. aureus). A novel biological strategy of coupling intracellular biochemical reactions for controllable biosynthesis of CdSe quantum dots by living B. subtilis cells was demonstrated, through which highly luminant and photostable fluorescent B. subtilis cells were achieved with good uniformity. With the help of the obtained fluorescent B. subtilis cells probes, S. aureus cells responded to co-cultured B. subtilis and to aggregate. The degree of aggregation was calculated and nonlinearly fitted to a polynomial model. Systematic investigations of their interactions implied that B. subtilis cells inhibit the growth of neighboring S. aureus cells, and this inhibition was affected by both the growth stage and the amount of surrounding B. subtilis cells. Compared to traditional methods of studying bacterial interaction between two species, such as solid culture medium colony observation and imaging mass spectrometry detection, the procedures were more simple, vivid, and photostable due to the efficient fluorescence intralabeling with less influence on the cells' surface, which might provide a new paradigm for future visualization of microbial behavior.

  1. Probing intra-cellular drug release event using activatable (OFF/ON) CdS:Mn/ZnS quantum dots (Qdots): spectroscopic studies to investigate interaction of Qdots with quencher

    Science.gov (United States)

    Tharkur, Jeremy; Teblum, Andrew; Basumallick, Srijita; Shah, Rikhav; Cantarero, Karishma; Maity, Niharika; Rifai, Sara; Doshi, Mona; Gesquiere, Andre J.; Santra, Swadeshmukul

    2013-02-01

    In recent years, activatable Quantum Dots (AQdots) are gaining popularity in a number of chemical and biological sensing applications. A basic design of AQdot probes involves a suitable quencher which is capable of altering optical properties of the Qdots. In our previous studies we have shown that CdS:Mn/ZnS fluorescence can be effectively quenched using small molecule quenchers (such as dopamine, chemotherapeutic drug) as well as iron oxide nanoparticle via electron/energy transfer process. We have also shown that the quenched Qdot fluorescence can be restored when the Qdots are separated from the quencher. Using Qdot based activatable probes, we detected intracellular drug release event. Qdot fluorescence was restored upon interaction with the intracellular glutathione (GSH). In this paper, we report a GSH induced quenching of water-soluble N-Acetyl Cysteine (NAC) surface-conjugated Cds:Mn/ZnS Qdots. Quenching of NAC-Qdots was due to aggregation of Qdots in solution. This aggregation induced fluorescence quenching phenomenon resembles with the self-quenching phenomenon of traditional organic fluorescence dyes at high concentrations. UV-VIS and fluorescence emission spectroscopy data support the interaction and binding of GSH with the NAC-Qdots. Increase in particle size due to GSH induced aggregation of NAC-Qdots was confirmed by the Dynamic Light Scattering (DLS) data.

  2. Atom-probe field-ion microscope for the study of the interaction of impurity atoms or alloying elements with defects

    International Nuclear Information System (INIS)

    Wagner, A.; Hall, T.M.; Seidman, D.N.

    1976-10-01

    A time-of-flight (TOF) atom-probe field-ion microscope (FIM) designed for the study of defects is described. This atom probe features: (1) a variable magnification internal-image-intensification system; (2) a liquid-helium goniometer stage; (3) a low-energy (less than or equal 3 keV) gas-ion gun for in-situ irradiations; (4) an ultra-high vacuum (approximately 3.10 -10 torr) chamber; (5) a high vacuum (approximately 10 -6 torr) specimen-exchange device; (6) a Chevron ion detector; and (7) an eight-channel digital timer with a +-10 nsec resolution for measuring the TOFs. The entire process of applying the evaporation pulse to the specimen, measuring the voltages, and analyzing the TOF data is controlled by a computer. With this system we can record and analyze 600 TOFmin. Results on unirradiated specimens of molybdenum, tungsten, W/25 at. % Re, Mo/1.0 at. % Ti, Mo/1.0 at. % Ti/0.08 at. % Zr and a special low swelling stainless steel alloy (LS1A) demonstrate the instrument's ability to quantitatively determine concentrations at the 5.10 -4 at fr level and to determine their spatial distribution with a resolution of a few angstroms

  3. Proximal Probes Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Proximal Probes Facility consists of laboratories for microscopy, spectroscopy, and probing of nanostructured materials and their functional properties. At the...

  4. Probe Techniques. Introductory Remarks

    Energy Technology Data Exchange (ETDEWEB)

    Emeleus, K. G. [School of Physics and Applied Mathematics, Queen' s University, Belfast (United Kingdom)

    1968-04-15

    In this brief introduction to the session on probes, the history of theii development is first touched on briefly. Reference is then made to the significance of the work to be described by Medicus, for conductivity and recombination calculations, and by Lam and Su, for a wide range of medium and higher pressure plasmas. Finally, a number of other probe topics are mentioned, including multiple probes; probes in electronegative plasmas; resonance probes; probes in noisy discharges; probes as oscillation detectors; use of probes where space-charge is not negligible. (author)

  5. Van Allen Probe observations of drift-bounce resonances with Pc 4 pulsations and wave–particle interactions in the pre-midnight inner magnetosphere

    Directory of Open Access Journals (Sweden)

    G. I. Korotova

    2015-08-01

    Full Text Available We present Van Allen Probe B observations of azimuthally limited, antisymmetric, poloidal Pc 4 electric and magnetic field pulsations in the pre-midnight sector of the magnetosphere from 05:40 to 06:00 UT on 1 May 2013. Oscillation periods were similar for the magnetic and electric fields and proton fluxes. The flux of energetic protons exhibited an energy-dependent response to the pulsations. Energetic proton variations were anticorrelated at medium and low energies. Although we attribute the pulsations to a drift-bounce resonance, we demonstrate that the energy-dependent response of the ion fluxes results from pulsation-associated velocities sweeping energy-dependent radial ion flux gradients back and forth past the spacecraft.

  6. INTERACT

    DEFF Research Database (Denmark)

    Jochum, Elizabeth; Borggreen, Gunhild; Murphey, TD

    This paper considers the impact of visual art and performance on robotics and human-computer interaction and outlines a research project that combines puppetry and live performance with robotics. Kinesics—communication through movement—is the foundation of many theatre and performance traditions ...

  7. Probing convex polygons with X-rays

    International Nuclear Information System (INIS)

    Edelsbrunner, H.; Skiena, S.S.

    1988-01-01

    An X-ray probe through a polygon measures the length of intersection between a line and the polygon. This paper considers the properties of various classes of X-ray probes, and shows how they interact to give finite strategies for completely describing convex n-gons. It is shown that (3n/2)+6 probes are sufficient to verify a specified n-gon, while for determining convex polygons (3n-1)/2 X-ray probes are necessary and 5n+O(1) sufficient, with 3n+O(1) sufficient given that a lower bound on the size of the smallest edge of P is known

  8. Radical probing of spliceosome assembly.

    Science.gov (United States)

    Grewal, Charnpal S; Kent, Oliver A; MacMillan, Andrew M

    2017-08-01

    Here we describe the synthesis and use of a directed hydroxyl radical probe, tethered to a pre-mRNA substrate, to map the structure of this substrate during the spliceosome assembly process. These studies indicate an early organization and proximation of conserved pre-mRNA sequences during spliceosome assembly. This methodology may be adapted to the synthesis of a wide variety of modified RNAs for use as probes of RNA structure and RNA-protein interaction. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. Radioactive Probes on Ferromagnetic Surfaces

    CERN Multimedia

    2002-01-01

    On the (broad) basis of our studies of nonmagnetic radioactive probe atoms on magnetic surfaces and at interfaces, we propose to investigate the magnetic interaction of magnetic probe atoms with their immediate environment, in particular of rare earth (RE) elements positioned on and in ferromagnetic surfaces. The preparation and analysis of the structural properties of such samples will be performed in the UHV chamber HYDRA at the HMI/Berlin. For the investigations of the magnetic properties of RE atoms on surfaces Perturbed Angular Correlation (PAC) measurements and Mössbauer Spectroscopy (MS) in the UHV chamber ASPIC (Apparatus for Surface Physics and Interfaces at CERN) are proposed.

  10. Development of a functional cell-based assay that probes the specific interaction between influenza A virus NP and its packaging signal sequence RNA.

    Science.gov (United States)

    Woo, Jiwon; Yu, Kyung Lee; Lee, Sun Hee; You, Ji Chang

    2015-02-06

    Although cis-acting packaging signal RNA sequences for the influenza virus NP encoding vRNA have been identified recently though genetic studies, little is known about the interaction between NP and the vRNA packaging signals either in vivo or in vitro. Here, we provide evidence that NP is able to interact specifically with the vRNA packaging sequence RNA within living cells and that the specific RNA binding activity of NP in vivo requires both the N-terminal and central region of the protein. This assay established would be a valuable tool for further detailed studies of the NP-packaging signal RNA interaction in living cells. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. Probing interactions between B-glucan and bile salts at atomic detail by 1H-13C NMR assays

    DEFF Research Database (Denmark)

    Mikkelsen, Mette Skau; Cornali, Sofia Bolvig; Jensen, Morten G

    2014-01-01

    Polysaccharides are prospective hosts for the delivery and sequestration of bioactive guest molecules. Polysaccharides of dietary fiber, specifically cereal (1 → 3)(1 → 4)-β-glucans, play a role in lowering the blood plasma cholesterol level in humans. Direct host-guest interactions between β...... salts and β-glucans. Experiments are consistent with stronger interactions at pH 5.3 than at pH 6.5 in this in vitro assay. The changes in bile salt and β-glucan signals suggest a stabilization of bile salt micelles and concomitant conformational changes in β-glucans....

  12. A fluorescent DNA based probe for Hg(II) based on thymine-Hg(II)-thymine interaction and enrichment via magnetized graphene oxide.

    Science.gov (United States)

    Li, Meng-Ke; Hu, Liu-Yin; Niu, Cheng-Gang; Huang, Da-Wei; Zeng, Guang-Ming

    2018-03-03

    The authors describe a fluorometric assay for the determination of Hg(II). A naphthalimide derivative is used as a label for a thymine (T) rich ssDNA, and graphene oxide magnetized with Fe 3 O 4 nanoparticles acts as a quencher and preconcentrators. In the absence of Hg(II), the labeled ssDNA does not separate from the magnetized graphene oxide. As a result, fluorescence is fully quenched. In the presence of Hg(II), a T-Hg(II)-T link is formed dues to the highly affinity between T and Hg(II). Hence, fluorescence is restored. The assay has a linear response in the 1.0 to 10.0 nM Hg(II) concentration range, and a 0.65 nM detection limit. The method is selective and sensitive. It was applied to the analysis of spiked environmental water samples, and data agreed well with those obtained by atomic fluorescence spectrometry. Graphical abstract Strategy of a fluorescent probe for detecting Hg(II). The method has a 0.65 nM detection limit and is selective. MGO: magnetized graphene oxide, AHN: a fluorescent derivative of naphthalimide.

  13. Acid-base interactions and secondary structures of poly-L-lysine probed by 15N and 13C solid state NMR and Ab initio model calculations.

    Science.gov (United States)

    Dos, Alexandra; Schimming, Volkmar; Tosoni, Sergio; Limbach, Hans-Heinrich

    2008-12-11

    The interactions of the 15N-labeled amino groups of dry solid poly-L-lysine (PLL) with various halogen and oxygen acids HX and the relation to the secondary structure have been studied using solid-state 15N and 13C CPMAS NMR spectroscopy (CP = cross polarization and MAS = magic angle spinning). For comparison, 15N NMR spectra of an aqueous solution of PLL were measured as a function of pH. In order to understand the effects of protonation and hydration on the 15N chemical shifts of the amino groups, DFT and chemical shielding calculations were performed on isolated methylamine-acid complexes and on periodic halide clusters of the type (CH3NH3(+)X(-))n. The combined experimental and computational results reveal low-field shifts of the amino nitrogens upon interaction with the oxygen acids HX = HF, H2SO4, CH3COOH, (CH3)2POOH, H3PO4, HNO3, and internal carbamic acid formed by reaction of the amino groups with gaseous CO2. Evidence is obtained that only hydrogen-bonded species of the type (Lys-NH2***H-X)n are formed in the absence of water. 15N chemical shifts are maximum when H is located in the hydrogen bond center and then decrease again upon full protonation, as found for aqueous solution at low pH. By contrast, halogen acids interact in a different way. They form internal salts of the type (Lys-NH3(+)X(-))n via the interaction of many acid-base pairs. This salt formation is possible only in the beta-sheet conformation. By contrast, the formation of hydrogen-bonded complexes can occur both in beta-sheet domains as well as in alpha-helical domains. The 15N chemical shifts of the protonated ammonium groups increase when the size of the interacting halogen anions is increased from chloride to iodide and when the number of the interacting anions is increased. Thus, the observed high-field 15N shift of ammonium groups upon hydration is the consequence of replacing interacting halogen atoms by oxygen atoms.

  14. Probing the interaction between the histone methyltransferase/deacetylase subunit RBBP4/7 and the transcription factor BCL11A in epigenetic complexes.

    Science.gov (United States)

    Moody, Rebecca Reed; Lo, Miao-Chia; Meagher, Jennifer L; Lin, Chang-Ching; Stevers, Nicholas O; Tinsley, Samantha L; Jung, Inkyung; Matvekas, Aleksas; Stuckey, Jeanne A; Sun, Duxin

    2018-02-09

    The transcription factor BCL11A has recently been reported to be a driving force in triple-negative breast cancer (TNBC), contributing to the maintenance of a chemoresistant breast cancer stem cell (BCSC) population. Although BCL11A was shown to suppress γ-globin and p21 and to induce MDM2 expression in the hematopoietic system, its downstream targets in TNBC are still unclear. For its role in transcriptional repression, BCL11A was found to interact with several corepressor complexes; however, the mechanisms underlying these interactions remain unknown. Here, we reveal that BCL11A interacts with histone methyltransferase (PRC2) and histone deacetylase (NuRD and SIN3A) complexes through their common subunit, RBBP4/7. In fluorescence polarization assays, we show that BCL11A competes with histone H3 for binding to the negatively charged top face of RBBP4. To define that interaction, we solved the crystal structure of RBBP4 in complex with an N-terminal peptide of BCL11A (residues 2-16, BCL11A(2-16)). The crystal structure identifies novel interactions between BCL11A and the side of the β-propeller of RBBP4 that are not seen with histone H3. We next show that BCL11A(2-16) pulls down RBBP4, RBBP7, and other components of PRC2, NuRD, and SIN3A from the cell lysate of the TNBC cell line SUM149. Furthermore, we demonstrate the therapeutic potential of targeting the RBBP4-BCL11A binding by showing that a BCL11A peptide can decrease aldehyde dehydrogenase-positive BCSCs and mammosphere formation capacity in SUM149. Together, our findings have uncovered a previously unidentified mechanism that BCL11A may use to recruit epigenetic complexes to regulate transcription and promote tumorigenesis. © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.

  15. Spin transport in intermediate-energy heavy-ion collisions as a probe of in-medium spin–orbit interactions

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Yin [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Xu, Jun, E-mail: xujun@sinap.ac.cn [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Li, Bao-An [Department of Physics and Astronomy, Texas A& M University-Commerce, Commerce, TX 75429-3011 (United States); Department of Applied Physics, Xi' an Jiao Tong University, Xi' an 710049 (China); Shen, Wen-Qing [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China)

    2016-11-15

    The spin up-down splitting of collective flows in intermediate-energy heavy-ion collisions as a result of the nuclear spin–orbit interaction is investigated within a spin- and isospin-dependent Boltzmann–Uehling–Uhlenbeck transport model SIBUU12. Using a Skyrme-type spin–orbit coupling quadratic in momentum, we found that the spin splittings of the directed flow and elliptic flow are largest in peripheral Au+Au collisions at beam energies of about 100–200 MeV/nucleon, and the effect is considerable even in smaller systems especially for nucleons with high transverse momenta. The collective flows of light clusters of different spin states are also investigated using an improved dynamical coalescence model with spin. Our study can be important in understanding the properties of in-medium nuclear spin–orbit interactions once the spin-dependent observables proposed in this work can be measured.

  16. Immobilised histidine tagged β2-adrenoceptor oriented by a diazonium salt reaction and its application in exploring drug-protein interaction using ephedrine and pseudoephedrine as probes.

    Science.gov (United States)

    Li, Qian; Bian, Liujiao; Zhao, Xinfeng; Gao, Xiaokang; Zheng, Jianbin; Li, Zijian; Zhang, Youyi; Jiang, Ru; Zheng, Xiaohui

    2014-01-01

    A new oriented method using a diazonium salt reaction was developed for linking β2-adrenoceptor (β2-AR) on the surface of macroporous silica gel. Stationary phase containing the immobilised receptor was used to investigate the interaction between β2-AR and ephedrine plus pseudoephedrine by zonal elution. The isotherms of the two drugs best fit the Langmuir model. Only one type of binding site was found for ephedrine and pseudoephedrine targeting β2-AR. At 37 °C, the association constants during the binding were (5.94±0.05)×103/M for ephedrine and (3.80±0.02) ×103/M for pseudoephedrine, with the binding sites of (8.92±0.06) ×10-4 M. Thermodynamic studies showed that the binding of the two compounds to β2-AR was a spontaneous reaction with exothermal processes. The ΔGθ, ΔHθ and ΔSθ for the interaction between ephedrine and β2-AR were -(22.33±0.04) kJ/mol, -(6.51±0.69) kJ/mol and 50.94±0.31 J/mol·K, respectively. For the binding of pseudoephedrine to the receptor, these values were -(21.17±0.02) kJ/mol, -(7.48±0.56) kJ/mol and 44.13±0.01 J/mol·K. Electrostatic interaction proved to be the driving force during the binding of the two drugs to β2-AR. The proposed immobilised method will have great potential for attaching protein to solid substrates and realizing the interactions between proteins and drugs.

  17. Single molecule force spectroscopy for in-situ probing oridonin inhibited ROS-mediated EGF-EGFR interactions in living KYSE-150 cells.

    Science.gov (United States)

    Pi, Jiang; Jin, Hua; Jiang, Jinhuan; Yang, Fen; Cai, Huaihong; Yang, Peihui; Cai, Jiye; Chen, Zheng W

    2017-05-01

    As the active anticancer component of Rabdosia Rubescens, oridonin has been proved to show strong anticancer activity in cancer cells, which is also found to be closely related to its specific inhibition effects on the EGFR tyrosine kinase activity. In this study, atomic force microscopy based single molecule force spectroscopy (AFM-SMFS) was used for real-time and in-situ detection of EGF-EGFR interactions in living esophageal cancer KYSE-150 cells to evaluate the anticancer activity of oridonin for the first time. Oridonin was found to induce apoptosis and also reduce EGFR expression in KYSE-150 cells. AFM-SMFS results demonstrated that oridonin could inhibit the binding between EGF and EGFR in KYSE-150 cells by decreasing the unbinding force and binding probability for EGF-EGFR complexes, which was further proved to be closely associated with the intracellular ROS level. More precise mechanism studies based on AFM-SMFS demonstrated that oridonin treatment could decrease the energy barrier width, increase the dissociation off rate constant and decrease the activation energy of EGF-EGFR complexes in ROS dependent way, suggesting oridonin as a strong anticancer agent targeting EGF-EGFR interactions in cancer cells through ROS dependent mechanism. Our results not only suggested oridonin as a strong anticancer agent targeting EGF-EGFR interactions in ROS dependent mechanism, but also highlighted AFM-SMFS as a powerful technique for pharmacodynamic studies by detecting ligand-receptor interactions, which was also expected to be developed into a promising tool for the screening and mechanism studies of drugs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Immobilised histidine tagged β2-adrenoceptor oriented by a diazonium salt reaction and its application in exploring drug-protein interaction using ephedrine and pseudoephedrine as probes.

    Directory of Open Access Journals (Sweden)

    Qian Li

    Full Text Available A new oriented method using a diazonium salt reaction was developed for linking β2-adrenoceptor (β2-AR on the surface of macroporous silica gel. Stationary phase containing the immobilised receptor was used to investigate the interaction between β2-AR and ephedrine plus pseudoephedrine by zonal elution. The isotherms of the two drugs best fit the Langmuir model. Only one type of binding site was found for ephedrine and pseudoephedrine targeting β2-AR. At 37 °C, the association constants during the binding were (5.94±0.05×103/M for ephedrine and (3.80±0.02 ×103/M for pseudoephedrine, with the binding sites of (8.92±0.06 ×10-4 M. Thermodynamic studies showed that the binding of the two compounds to β2-AR was a spontaneous reaction with exothermal processes. The ΔGθ, ΔHθ and ΔSθ for the interaction between ephedrine and β2-AR were -(22.33±0.04 kJ/mol, -(6.51±0.69 kJ/mol and 50.94±0.31 J/mol·K, respectively. For the binding of pseudoephedrine to the receptor, these values were -(21.17±0.02 kJ/mol, -(7.48±0.56 kJ/mol and 44.13±0.01 J/mol·K. Electrostatic interaction proved to be the driving force during the binding of the two drugs to β2-AR. The proposed immobilised method will have great potential for attaching protein to solid substrates and realizing the interactions between proteins and drugs.

  19. Interaction and energy transfer studies between bovine serum albumin and CdTe quantum dots conjugates: CdTe QDs as energy acceptor probes.

    Science.gov (United States)

    Kotresh, M G; Inamdar, L S; Shivkumar, M A; Adarsh, K S; Jagatap, B N; Mulimani, B G; Advirao, G M; Inamdar, S R

    2017-06-01

    In this paper, a systematic investigation of the interaction of bovine serum albumin (BSA) with water-soluble CdTe quantum dots (QDs) of two different sizes capped with carboxylic thiols is presented based on steady-state and time-resolved fluorescence measurements. Efficient Förster resonance energy transfer (FRET) was observed to occur from BSA donor to CdTe acceptor as noted from reduction in the fluorescence of BSA and enhanced fluorescence from CdTe QDs. FRET parameters such as Förster distance, spectral overlap integral, FRET rate constant and efficiency were determined. The quenching of BSA fluorescence in aqueous solution observed in the presence of CdTe QDs infers that fluorescence resonance energy transfer is primarily responsible for the quenching phenomenon. Bimolecular quenching constant (k q ) determined at different temperatures and the time-resolved fluorescence data provide additional evidence for this. The binding stoichiometry and various thermodynamic parameters are evaluated by using the van 't Hoff equation. The analysis of the results suggests that the interaction between BSA and CdTe QDs is entropy driven and hydrophobic forces play a key role in the interaction. Binding of QDs significantly shortened the fluorescence lifetime of BSA which is one of the hallmarks of FRET. The effect of size of the QDs on the FRET parameters are discussed in the light of FRET parameters obtained. Copyright © 2016 John Wiley & Sons, Ltd.

  20. Mobile Game Probes

    DEFF Research Database (Denmark)

    Borup Lynggaard, Aviaja

    2006-01-01

    This paper will examine how probes can be useful for game designers in the preliminary phases of a design process. The work is based upon a case study concerning pervasive mobile phone games where Mobile Game Probes have emerged from the project. The new probes are aimed towards a specific target...... group and the goal is to specify the probes so they will cover the most relevant areas for our project. The Mobile Game Probes generated many interesting results and new issues occurred, since the probes came to be dynamic and favorable for the process in new ways....

  1. Behavior of cesium and thallium cations inside a calixarene cavity as probed by nuclear spin relaxation. Evidence of cation-pi interactions in water.

    Science.gov (United States)

    Cuc, Diana; Bouguet-Bonnet, Sabine; Morel-Desrosiers, Nicole; Morel, Jean-Pierre; Mutzenhardt, Pierre; Canet, Daniel

    2009-08-06

    We have studied the complexes formed between the p-sulfonatocalix[4]arene and cesium or thallium metal cation, first by carbon-13 longitudinal relaxation of the calixarene molecule at two values of the magnetic field B(0). From the longitudinal relaxation times of an aromatic carbon directly bonded to a proton, thus subjected essentially to the dipolar interaction with that proton, we could obtain the correlation time describing the reorientation of the CH bond. The rest of this study has demonstrated that it is also the correlation time describing the tumbling of the whole calixarene assembly. From three non-proton-bearing carbons of the aromatic cycles (thus subjected to the chemical shift anisotropy and dipolar mechanisms), we have been able to determine the variation of the chemical shift anisotropy when going from the free to the complex form of the calixarene. These variations not only provide the location of the cation inside the calixarene cavity but also constitute a direct experimental proof of the cation-pi interactions. These results are complemented by cesium and thallium relaxation measurements performed again at two values of the magnetic field B(0). An estimation of the mean distance between the cation and the calixarene protons could be obtained. These measurements have also revealed an important chemical shift anisotropy of thallium upon complexation.

  2. Probing molecular interactions of poly(styrene-co-maleic acid) with lipid matrix models to interpret the therapeutic potential of the co-polymer.

    Science.gov (United States)

    Banerjee, Shubhadeep; Pal, Tapan K; Guha, Sujoy K

    2012-03-01

    To understand and maximize the therapeutic potential of poly(styrene-co-maleic acid) (SMA), a synthetic, pharmacologically-active co-polymer, its effect on conformation, phase behavior and stability of lipid matrix models of cell membranes were investigated. The modes of interaction between SMA and lipid molecules were also studied. While, attenuated total reflection-Fourier-transform infrared (ATR-FTIR) and static (31)P nuclear magnetic resonance (NMR) experiments detected SMA-induced conformational changes in the headgroup region, differential scanning calorimetry (DSC) studies revealed thermotropic phase behavior changes of the membranes. (1)H NMR results indicated weak immobilization of SMA within the bilayers. Molecular interpretation of the results indicated the role of hydrogen-bond formation and hydrophobic forces between SMA and zwitterionic phospholipid bilayers. The extent of membrane fluidization and generation of isotropic phases were affected by the surface charge of the liposomes, and hence suggested the role of electrostatic interactions between SMA and charged lipid headgroups. SMA was thus found to directly affect the structural integrity of model membranes. Copyright © 2011 Elsevier B.V. All rights reserved.

  3. Probing the interaction of a new synthesized CdTe quantum dots with human serum albumin and bovine serum albumin by spectroscopic methods

    Energy Technology Data Exchange (ETDEWEB)

    Bardajee, Ghasem Rezanejade, E-mail: rezanejad@pnu.ac.ir; Hooshyar, Zari

    2016-05-01

    A novel CdTe quantum dots (QDs) were prepared in aqueous phase via a facile method. At first, poly (acrylic amide) grafted onto sodium alginate (PAAm-g-SA) were successfully synthesized and then TGA capped CdTe QDs (CdTe-TGA QDs) were embed into it. The prepared CdTe-PAAm-g-SA QDs were optimized and characterized by transmission electron microscopy (TEM), thermo-gravimetric (TG) analysis, Fourier transform infrared (FT-IR), UV–vis and fluorescence spectroscopy. The characterization results indicated that CdTe-TGA QDs, with particles size of 2.90 nm, were uniformly dispersed on the chains of PAAm-g-SA biopolymer. CdTe-PAAm-g-SA QDs also exhibited excellent UV–vis absorption and high fluorescence intensity. To explore biological behavior of CdTe-PAAm-g-SA QDs, the interactions between CdTe-PAAm-g-SA QDs and human serum albumin (HSA) (or bovine serum albumin (BSA)) were investigated by cyclic voltammetry, FT-IR, UV–vis, and fluorescence spectroscopic. The results confirmed the formation of CdTe-PAAm-g-SA QDs-HSA (or BSA) complex with high binding affinities. The thermodynamic parameters (ΔG < 0, ΔH < 0 and ΔS < 0) were indicated that binding reaction was spontaneous and van der Waals interactions and hydrogen-bond interactions played a major role in stabilizing the CdTe-PAAm-g-SA QDs-HSA (or BSA) complexes. The binding distance between CdTe-PAAm-g-SA QDs and HSA (or BSA)) was calculated about 1.37 nm and 1.27 nm, respectively, according to Forster non-radiative energy transfer theory (FRET). Analyzing FT-IR spectra showed that the formation of QDs-HSA and QDs-BSA complexes led to conformational changes of the HSA and BSA proteins. All these experimental results clarified the effective transportation and elimination of CdTe-PAAm-g-SA QDs in the body by binding to HSA and BSA, which could be a useful guideline for the estimation of QDs as a drug carrier. - Highlights: • The CdTe quantum dots coated with polyacrylamide grafted onto sodium alginate. • The

  4. Probing the impact of magnetic interactions on the lattice dynamics of two-dimensional Ti2X (X = C, N) MXenes.

    Science.gov (United States)

    Sternik, Małgorzata; Wdowik, Urszula D

    2018-03-14

    Dynamical properties of the two-dimensional Ti 2 C and Ti 2 N MXenes were investigated using density functional theory and discussed in connection with their structures and electronic properties. To elucidate the influence of magnetic interactions on the fundamental properties of these systems, the nonmagnetic, ferromagnetic and three distinct antiferromagnetic spin arrangements on titanium sublattice were considered. Each magnetic configuration was also studied at two directions of the spin magnetic moment with respect to the MXene layer. The zero-point energy motion, following from the phonon calculations, was taken into account while analyzing the energetic stability of the magnetic phases against the nonmagnetic solution. This contribution was found not to change a sequence of the energetic stability of the considered magnetic structures of Ti 2 X (X = C, N) MXenes. Both Ti 2 X (X = C, N) systems are shown to prefer antiferromagnetic arrangement of spins between Ti layers and the ferromagnetic order within each layer. This energetically privileged phase is semiconducting for Ti 2 C and metallic for Ti 2 N. The type of magnetic order as well as the in-plane or out-of-plane spin polarizations have a relatively small impact on the structural parameters, Ti-X bonding length, force constants and phonon spectra of both Ti 2 X systems, leading to observable differences only between the nonmagnetic and any other magnetic configurations. Nonetheless, a noticeable effect of the spin orientation on degeneracy of the Ti-3d orbitals is encountered. The magnetic interactions affect to a great extent the positions and intensities of the Raman-active modes, and hence one could exploit this effect for experimental verification of the theoretically predicted magnetic state of Ti 2 X monolayers. Theoretical phonon spectra of Ti 2 X (X = C, N) MXenes exhibit a linear dependence on energy in the long-wavelength limit, which is typical for a 2D system.

  5. Probing DNA interactions with proteins using a single-molecule toolbox: inside the cell, in a test tube and in a computer.

    Science.gov (United States)

    Wollman, Adam J M; Miller, Helen; Zhou, Zhaokun; Leake, Mark C

    2015-04-01

    DNA-interacting proteins have roles in multiple processes, many operating as molecular machines which undergo dynamic meta-stable transitions to bring about their biological function. To fully understand this molecular heterogeneity, DNA and the proteins that bind to it must ideally be interrogated at a single molecule level in their native in vivo environments, in a time-resolved manner, fast enough to sample the molecular transitions across the free-energy landscape. Progress has been made over the past decade in utilizing cutting-edge tools of the physical sciences to address challenging biological questions concerning the function and modes of action of several different proteins which bind to DNA. These physiologically relevant assays are technically challenging but can be complemented by powerful and often more tractable in vitro experiments which confer advantages of the chemical environment with enhanced detection signal-to-noise of molecular signatures and transition events. In the present paper, we discuss a range of techniques we have developed to monitor DNA-protein interactions in vivo, in vitro and in silico. These include bespoke single-molecule fluorescence microscopy techniques to elucidate the architecture and dynamics of the bacterial replisome and the structural maintenance of bacterial chromosomes, as well as new computational tools to extract single-molecule molecular signatures from live cells to monitor stoichiometry, spatial localization and mobility in living cells. We also discuss recent developments from our laboratory made in vitro, complementing these in vivo studies, which combine optical and magnetic tweezers to manipulate and image single molecules of DNA, with and without bound protein, in a new super-resolution fluorescence microscope.

  6. A study on the interaction of horse heart cytochrome c with some conventional and ionic liquid surfactants probed by ultraviolet-visible and fluorescence spectroscopic techniques.

    Science.gov (United States)

    Mondal, Satyajit; Das, Bijan

    2018-06-05

    The interactions of a protein cytochrome c with some selected conventional and ionic liquid surfactants have been investigated at pH7.4 using ultraviolet-visible and fluorescence spectroscopic techniques. We used four conventional surfactants - cetyltrimethylammonium bromide (CTAB), dodecyltrimethylammonium bromide (DTAB), sodium N-dodecanoylsarcosinate (SDDS), and N-decanoyl-N-methylglucamine (Mega 10), and a surface active ionic liquid 1-hexadecyl-3-methylimidazolium chloride (C 16 MeImCl). All the investigated surfactants were found to induce an unfolding of the protein cytochrome c. In presence of CTAB, SDDS and C 16 MeImCl, the heme iron atom was found to loose methionine from its axial position. Differential binding of the surfactant monomers and their micelles to the protein molecules was inferred. The ionic surfactants were found to be more effective than the nonionic one in unfolding the investigated protein. However, the extent of binding of CTAB/C 16 MeImCl to cytochrome c reaches a plateau past the critical micellization concentration (cmc) of the surfactant. For each of the cytochrome c-DTAB, cytochrome c-SDDS and cytochrome c-Mega 10 system, although there exists an inflection in the surfactant-binding, saturation point could not be detected. It has been demonstrated from the ultraviolet-visible spectral studies that the oxidation state of iron in cytochrome c does not change when the protein binds with the investigated surfactants. Copyright © 2018 Elsevier B.V. All rights reserved.

  7. Probing the binding of an endocrine disrupting compound-Bisphenol F to human serum albumin: insights into the interactions of harmful chemicals with functional biomacromolecules.

    Science.gov (United States)

    Pan, Fang; Xu, Tianci; Yang, Lijun; Jiang, Xiaoqing; Zhang, Lei

    2014-11-11

    Bisphenol F (BPF) as an endocrine disrupting compounds (EDCs) pollutant in the environment poses a great threat to human health. To evaluate the toxicity of BPF at the protein level, the effects of BPF on human serum albumin (HSA) were investigated at three temperatures 283, 298, and 308 K by multiple spectroscopic techniques. The experimental results showed that BPF effectively quenched the intrinsic fluorescence of HSA via static quenching. The number of binding sites, the binding constant, the thermodynamic parameters and the binding subdomain were measured, and indicated that BPF could spontaneously bind with HSA on subdomain IIA through H-bond and van der Waals interactions. Furthermore, the conformation of HSA was demonstrably changed in the presence of BPF. The work provides accurate and full basic data for clarifying the binding mechanisms of BPF with HSA in vivo and is helpful for understanding its effect on protein function during its transportation and distribution in blood. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Synthetic assembly of novel avidin-biotin-GlcNAc (ABG) complex as an attractive bio-probe and its interaction with wheat germ agglutinin (WGA).

    Science.gov (United States)

    Kumari, Amrita; Koyama, Tetsuo; Hatano, Ken; Matsuoka, Koji

    2016-10-01

    A tetravalent GlcNAc pendant glycocluster was constructed with terminal biotin through C6 linker. To acquire the multivalent carbohydrate-protein interactions, we synthesized a glycopolymer of tetrameric structure using N-acetyl-d-glucosamine (GlcNAc) as the target carbohydrate by the use of 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMT-MM) as coupling reagent, followed by biotin-avidin complexation leading to the formation of glycocluster of avidin-biotin-GlcNAc conjugate (ABG complex). The dynamic light scattering (DLS) system was implied for size detection and to check the binding affinity of GlcNAc conjugate with a WGA lectin we use fluorometric assay by means of specific excitation of tryptophan at λex 295nm and it was found to be very high Ka∼1.39×10(7) M(-1) in case of ABG complex as compared to GlcNAc only Ka∼1.01×10(4) M(-1) with the phenomenon proven to be due to glycocluster effect. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Probing the Unique Contributions of Self-Concept, Task Values, and Their Interactions Using Multiple Value Facets and Multiple Academic Outcomes

    Directory of Open Access Journals (Sweden)

    Jiesi Guo

    2016-01-01

    Full Text Available Drawing on expectancy-value theory, the present study examined the unique contributions of the four major value beliefs and self-concept on achievement, self-reported effort, and teacher-rated behavioral engagement in mathematics. In particular, we examined the multiplicative effects of self-concept and task values on educational outcomes using the latent moderated structural equation approach. Participants were 1,868 German ninth-grade students. The data analyses relied on a higher-order structure of value beliefs, which is suited to parsing the differential patterns of predictive relations for different value beliefs. The findings revealed that (a self-concept was more predictive of achievement, whereas value beliefs were more predictive of self-rated effort; (b self-concept and value beliefs emerged as equally important predictors of teacher-reported engagement; (c among the four value beliefs, achievement was more associated with low cost, whereas effort was more associated with attainment value; and (d latent interactions between self-concept and value beliefs predicted the three outcomes synergistically.

  10. A study on the interaction of horse heart cytochrome c with some conventional and ionic liquid surfactants probed by ultraviolet-visible and fluorescence spectroscopic techniques

    Science.gov (United States)

    Mondal, Satyajit; Das, Bijan

    2018-06-01

    The interactions of a protein cytochrome c with some selected conventional and ionic liquid surfactants have been investigated at pH 7.4 using ultraviolet-visible and fluorescence spectroscopic techniques. We used four conventional surfactants - cetyltrimethylammonium bromide (CTAB), dodecyltrimethylammonium bromide (DTAB), sodium N-dodecanoylsarcosinate (SDDS), and N-decanoyl-N-methylglucamine (Mega 10), and a surface active ionic liquid 1-hexadecyl-3-methylimidazolium chloride (C16MeImCl). All the investigated surfactants were found to induce an unfolding of the protein cytochrome c. In presence of CTAB, SDDS and C16MeImCl, the heme iron atom was found to loose methionine from its axial position. Differential binding of the surfactant monomers and their micelles to the protein molecules was inferred. The ionic surfactants were found to be more effective than the nonionic one in unfolding the investigated protein. However, the extent of binding of CTAB/C16MeImCl to cytochrome c reaches a plateau past the critical micellization concentration (cmc) of the surfactant. For each of the cytochrome c-DTAB, cytochrome c-SDDS and cytochrome c-Mega 10 system, although there exists an inflection in the surfactant-binding, saturation point could not be detected. It has been demonstrated from the ultraviolet-visible spectral studies that the oxidation state of iron in cytochrome c does not change when the protein binds with the investigated surfactants.

  11. Probe-diverse ptychography

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, I., E-mail: isaac.russellpeterson@rmit.edu.au [ARC Centre of Excellence for Coherent X-ray Science, the University of Melbourne, School of Physics, Victoria 3010 (Australia); Harder, R. [Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439 (United States); Robinson, I.K. [Research Complex at Harwell, Didcot, Oxfordshire OX11 0DE (United Kingdom); London Centre for Nanotechnology, University College London, London WC1H 0AH (United Kingdom)

    2016-12-15

    We propose an extension of ptychography where the target sample is scanned separately through several probes with distinct amplitude and phase profiles and a diffraction image is recorded for each probe and each sample translation. The resulting probe-diverse dataset is used to iteratively retrieve high-resolution images of the sample and all probes simultaneously. The method is shown to yield significant improvement in the reconstructed sample image compared to the image obtained using the standard single-probe ptychographic phase-retrieval scheme.

  12. The Galaxy Evolution Probe

    Science.gov (United States)

    Glenn, Jason; Galaxy Evolution Probe Team

    2018-01-01

    The Galaxy Evolution Probe (GEP) is a concept for a far-infrared observatory to survey large regions of sky for star-forming galaxies from z = 0 to beyond z = 3. Our knowledge of galaxy formation is incomplete and requires uniform surveys over a large range of redshifts and environments to accurately describe mass assembly, star formation, supermassive black hole growth, interactions between these processes, and what led to their decline from z ~ 2 to the present day. Infrared observations are sensitive to dusty, star-forming galaxies, which have bright polycyclic aromatic hydrocarbon (PAH) emission features and warm dust continuum in the rest-frame mid infrared and cooler thermal dust emission in the far infrared. Unlike previous far-infrared continuum surveys, the GEP will measure photometric redshifts commensurate with galaxy detections from PAH emission and Si absorption features, without the need for obtaining spectroscopic redshifts of faint counterparts at other wavelengths.The GEP design includes a 2 m diameter telescope actively cooled to 4 K and two instruments: (1) An imager covering 10 to 300 um with 25 spectral resolution R ~ 8 bands (with lower R at the longest wavelengths) to detect star-forming galaxies and measure their redshifts photometrically. (2) A 23 – 190 um, R ~ 250 dispersive spectrometer for redshift confirmation and identification of obscured AGN using atomic fine-structure lines. Lines including [Ne V], [O IV], [O III], [O I], and [C II] will probe gas physical conditions, radiation field hardness, and metallicity. Notionally, the GEP will have a two-year mission: galaxy surveys with photometric redshifts in the first year and a second year devoted to follow-up spectroscopy. A comprehensive picture of star formation in galaxies over the last 10 billion years will be assembled from cosmologically relevant volumes, spanning environments from field galaxies and groups, to protoclusters, to dense galaxy clusters.Commissioned by NASA, the

  13. Interaction of Cu(II)-meso-tetrakis(n-N-methylpyridiniumyl)porphyrin (n = 2,3,4) with Native and Synthetic Polynucleotides Probed by Polarized Spectroscopy

    International Nuclear Information System (INIS)

    Lee, Mi Jin; Kim, Seog K.; Kim, Jong Moon; Lee, Dong Jin; Lee, Gil Jun

    2005-01-01

    The interactions of Cu(II)-meso-Tetrakis(n-N-methylpyridiniumyl)porphyrin (n = 2,3,4), respectively referred to as o-, m- and p-CuTMPyP, and DNA, poly[d(A-T) 2 ] and poly[d(G-C) 2 ] were investigated by circular and linear dichroism (CD and LD). In the o-CuTMPyP case, in which the rotation of the pyridinium ring is prevented, the shape of the CD spectrum when associated to DNA and poly[d(A-T) 2 ] resembles and is characterized by a positive band at a low drug to DNA concentration ratio (R ratio) and is bisignate at a high R ratio. The former CD spectrum shape has been attributed to porphyrin that is bound monomerically outside of DNA while the latter can be attributed to those that are stacked. When o-CuTMPyP is bound to poly[d(G-C) 2 ], the excitonic CD appeared at a relatively high R ratio. In contrast, a characteristic negative CD band in the Soret region was apparent for both m- and p-CuTMPyP when bound to DNA and poly[d(G-C) 2 ] at the low R ratios, indicating that the porphyrin molecule intercalates. However, the DNA is bent near the intercalation site and the plane of the porphyrin molecule tilts relative to the DNA helix axis, as judged by the magnitude of the reduced LD. Various stacking patterns were identified by the shape of the CD spectrum for m- and p-CuTMPyP when bound to poly[d(A-T) 2 ]. Three species for the former complex and two for the latter complex were found which may reflect the extent of the stacking

  14. Probing the interaction forces of prostate cancer cells with collagen I and bone marrow derived stem cells on the single cell level.

    Directory of Open Access Journals (Sweden)

    Ediz Sariisik

    Full Text Available Adhesion of metastasizing prostate carcinoma cells was quantified for two carcinoma model cell lines LNCaP (lymph node-specific and PC3 (bone marrow-specific. By time-lapse microscopy and force spectroscopy we found PC3 cells to preferentially adhere to bone marrow-derived mesenchymal stem cells (SCP1 cell line. Using atomic force microscopy (AFM based force spectroscopy, the mechanical pattern of the adhesion to SCP1 cells was characterized for both prostate cancer cell lines and compared to a substrate consisting of pure collagen type I. PC3 cells dissipated more energy (27.6 aJ during the forced de-adhesion AFM experiments and showed significantly more adhesive and stronger bonds compared to LNCaP cells (20.1 aJ. The characteristic signatures of the detachment force traces revealed that, in contrast to the LNCaP cells, PC3 cells seem to utilize their filopodia in addition to establish adhesive bonds. Taken together, our study clearly demonstrates that PC3 cells have a superior adhesive affinity to bone marrow mesenchymal stem cells, compared to LNCaP. Semi-quantitative PCR on both prostate carcinoma cell lines revealed the expression of two Col-I binding integrin receptors, α1β1 and α2β1 in PC3 cells, suggesting their possible involvement in the specific interaction to the substrates. Further understanding of the exact mechanisms behind this phenomenon might lead to optimized therapeutic applications targeting the metastatic behavior of certain prostate cancer cells towards bone tissue.

  15. Traversing probe system

    International Nuclear Information System (INIS)

    Mashburn, D.N.; Stevens, R.H.; Woodall, H.C.

    1977-01-01

    This invention comprises a rotatable annular probe-positioner which carries at least one radially disposed sensing probe, such as a Pitot tube having a right-angled tip. The positioner can be coaxially and rotatably mounted within a compressor casing or the like and then actuated to orient the sensing probe as required to make measurements at selected stations in the annulus between the positioner and compressor casing. The positioner can be actuated to (a) selectively move the probe along its own axis, (b) adjust the yaw angle of the right-angled probe tip, and (c) revolve the probe about the axis common to the positioner and casing. A cam plate engages a cam-follower portion of the probe and normally rotates with the positioner. The positioner includes a first-motor-driven ring gear which effects slidable movement of the probe by rotating the positioner at a time when an external pneumatic cylinder is actuated to engage the cam plate and hold it stationary. When the pneumatic cylinder is not actuated, this ring gear can be driven to revolve the positioner and thus the probe to a desired circumferential location about the above-mentioned common axis. A second motor-driven ring gear included in the positioner can be driven to rotate the probe about its axis, thus adjusting the yaw angle of the probe tip. The positioner can be used in highly corrosive atmosphere, such as gaseous uranium hexafluoride. 10 claims, 6 figures

  16. Traversing probe system

    Science.gov (United States)

    Mashburn, Douglas N.; Stevens, Richard H.; Woodall, Harold C.

    1977-01-01

    This invention comprises a rotatable annular probe-positioner which carries at least one radially disposed sensing probe, such as a Pitot tube having a right-angled tip. The positioner can be coaxially and rotatably mounted within a compressor casing or the like and then actuated to orient the sensing probe as required to make measurements at selected stations in the annulus between the positioner and compressor casing. The positioner can be actuated to (a) selectively move the probe along its own axis, (b) adjust the yaw angle of the right-angled probe tip, and (c) revolve the probe about the axis common to the positioner and casing. A cam plate engages a cam-follower portion of the probe and normally rotates with the positioner. The positioner includes a first-motor-driven ring gear which effects slidable movement of the probe by rotating the positioner at a time when an external pneumatic cylinder is actuated to engage the cam plate and hold it stationary. When the pneumatic cylinder is not actuated, this ring gear can be driven to revolve the positioner and thus the probe to a desired circumferential location about the above-mentioned common axis. A second motor-driven ring gear included in the positioner can be driven to rotate the probe about its axis, thus adjusting the yaw angle of the probe tip. The positioner can be used in highly corrosive atmosphere, such as gaseous uranium hexafluoride.

  17. Electrical resistivity probes

    Science.gov (United States)

    Lee, Ki Ha; Becker, Alex; Faybishenko, Boris A.; Solbau, Ray D.

    2003-10-21

    A miniaturized electrical resistivity (ER) probe based on a known current-voltage (I-V) electrode structure, the Wenner array, is designed for local (point) measurement. A pair of voltage measuring electrodes are positioned between a pair of current carrying electrodes. The electrodes are typically about 1 cm long, separated by 1 cm, so the probe is only about 1 inch long. The electrodes are mounted to a rigid tube with electrical wires in the tube and a sand bag may be placed around the electrodes to protect the electrodes. The probes can be positioned in a borehole or on the surface. The electrodes make contact with the surrounding medium. In a dual mode system, individual probes of a plurality of spaced probes can be used to measure local resistance, i.e. point measurements, but the system can select different probes to make interval measurements between probes and between boreholes.

  18. Modulated microwave microscopy and probes used therewith

    Science.gov (United States)

    Lai, Keji; Kelly, Michael; Shen, Zhi-Xun

    2012-09-11

    A microwave microscope including a probe tip electrode vertically positionable over a sample and projecting downwardly from the end of a cantilever. A transmission line connecting the tip electrode to the electronic control system extends along the cantilever and is separated from a ground plane at the bottom of the cantilever by a dielectric layer. The probe tip may be vertically tapped near or at the sample surface at a low frequency and the microwave signal reflected from the tip/sample interaction is demodulated at the low frequency. Alternatively, a low-frequency electrical signal is also a non-linear electrical element associated with the probe tip to non-linearly interact with the applied microwave signal and the reflected non-linear microwave signal is detected at the low frequency. The non-linear element may be semiconductor junction formed near the apex of the probe tip or be an FET formed at the base of a semiconducting tip.

  19. Disorder and intermolecular interactions in a family of tetranuclear Ni(II) complexes probed by high-frequency electron paramagnetic resonance.

    Science.gov (United States)

    Lawrence, Jon; Yang, En-Che; Edwards, Rachel; Olmstead, Marilyn M; Ramsey, Chris; Dalal, Naresh S; Gantzel, Peter K; Hill, Stephen; Hendrickson, David N

    2008-03-17

    structure splittings for complex 3. This behavior is thought to be due to the onset of short-range magnetic correlations/coherences between molecules caused by weak intermolecular magnetic exchange interactions.

  20. Measuring probe for a nuclear reactor

    International Nuclear Information System (INIS)

    Overhoff, T.

    1976-01-01

    A coaxial cable is helically wound into two concentric coils, forming the one end of the probe. At the other end of the probe, the inner conductor's ends are wired to the outer conducter's two extremities by a conductor made of a material with low neutron and gamma interaction cross-section. The direct current produced by this self-powered detector is frequency filtered in order to separate the contributions of the neutron induced secondary-electrons from the photo-electrons, and from the thermally excited conduction electrons. Neutron and gamma fluxes, as well as temperature are therefore determined by using a single probe. (RW) [de

  1. X ray emission: a tool and a probe for laser - clusters interaction; L'emission X: un outil et une sonde pour l'interaction laser - agregats

    Energy Technology Data Exchange (ETDEWEB)

    Prigent, Ch

    2004-12-01

    In intense laser-cluster interaction, the experimental results show a strong energetic coupling between radiation and matter. We have measured absolute X-ray yields and charge state distributions under well control conditions as a function of physical parameters governing the interaction; namely laser intensity, pulse duration, wavelength or polarization state of the laser light, the size and the species of the clusters (Ar, Kr, Xe). We have highlighted, for the first time, an intensity threshold in the X-ray production very low ({approx} 2.10{sup 14} W/cm{sup 2} for a pulse duration of 300 fs) which can results from an effect of the dynamical polarisation of clusters in an intense electric field. A weak dependence with the wavelength (400 nm / 800 nm) on the absolute X-ray yields has been found. Moreover, we have observed a saturation of the X-ray emission probability below a critical cluster size. (author)

  2. Strong interactions studies with medium energy probes

    International Nuclear Information System (INIS)

    Seth, K.K.

    1993-10-01

    This progress report refers to the period August 1992 to August 1993, which includes the first year of the three-year period December 1, 1992--November 30, 1995 of the existing research contract. As anticipated in the 1992--1995 proposal the major preoccupation during 1992--1993 was with Fermilab experiment E760. This experiment, whose primary objective is to make very high-resolution study of Charmonium Spectroscopy via proton-antiproton annihilations, has turned out to be a veritable gold-mine of exciting hadronic physics in other areas as well. These include the proton from factor in the time-life region, proton-antiproton forward scattering, QCD scaling laws, and light quark spectroscopy. A large fraction of the data from E760 have been analyzed during this year, and several papers have been published. In addition to the E760 experiment at Fermilab continued progress was made earlier nuclear physics-related experiments at LAMPF, MIT, and NIKHEF, and their results for publication. Topics include high- resolution electron scattering, quasi-free electron scattering and low-energy pion double charge exchange

  3. Electromagnetic probes of strongly interacting matter

    Indian Academy of Sciences (India)

    2015-05-07

    May 7, 2015 ... The nuclear matter under extreme conditions of temperatures () and baryonic densities () undergoes a phase transition to quark gluon plasma (QGP). It is expected that such extreme conditions can be achieved by colliding nuclei at ultrarelativistic energies. In the present review, the suitability of ...

  4. Probing electronic interactions using electron tunneling

    Indian Academy of Sciences (India)

    pratap

    Sample preparation. Chamber. Sample manipulators. Vibration Isolation. Table. Cryostat. Load lock. STM Head. Magnet. Sample holder. Tip. Tip holder. Piezo electric tube. Coarse positioner. Macor. Cu housing for sample holder. PCB. Cu shielding can. Steel studs. Our Toy: The TIFR milli-Kelvin STM. Lowest temperature:.

  5. Probe tests microweld strength

    Science.gov (United States)

    1965-01-01

    Probe is developed to test strength of soldered, brazed or microwelded joints. It consists of a spring which may be adjusted to the desired test pressure by means of a threaded probe head, and an indicator lamp. Device may be used for electronic equipment testing.

  6. Probing the environment of an inaccessible system by a qubit ancilla

    International Nuclear Information System (INIS)

    Campbell, S.; Paternostro, M.; Kim, M. S.; Bose, S.

    2010-01-01

    We study the conditions for probing the environment affecting an inaccessible system by means of continuous interaction and measurements performed only on a probe. The scheme exploits the statistical properties of the probe at its steady state and simple data postprocessing. Our results, highlighting the roles played by interaction and entanglement in this process, are both pragmatically relevant and fundamentally interesting.

  7. Calibration models for high enthalpy calorimetric probes.

    Science.gov (United States)

    Kannel, A

    1978-07-01

    The accuracy of gas-aspirated liquid-cooled calorimetric probes used for measuring the enthalpy of high-temperature gas streams is studied. The error in the differential temperature measurements caused by internal and external heat transfer interactions is considered and quantified by mathematical models. The analysis suggests calibration methods for the evaluation of dimensionless heat transfer parameters in the models, which then can give a more accurate value for the enthalpy of the sample. Calibration models for four types of calorimeters are applied to results from the literature and from our own experiments: a circular slit calorimeter developed by the author, single-cooling jacket probe, double-cooling jacket probe, and split-flow cooling jacket probe. The results show that the models are useful for describing and correcting the temperature measurements.

  8. Probing nuclear structure with nucleons

    International Nuclear Information System (INIS)

    Bauge, E.

    2007-01-01

    The goal of this lecture is to show how nucleon scattering can be used to probe the structure of target nuclei, and how nucleon scattering observables can be interpreted in terms of nuclear structure using microscopic optical potentials. After a brief overview of the specificities of nucleon-nucleus scattering, and a quick reminder on scattering theory, the main part of this lecture is devoted to the construction of optical potentials in which the target nuclei structure information is folded with an effective interaction. Several examples of such microscopic optical model potentials are given. (author)

  9. Probing a gravitational cat state

    International Nuclear Information System (INIS)

    Anastopoulos, C; Hu, B L

    2015-01-01

    We investigate the nature of a gravitational two-state system (G2S) in the simplest setup in Newtonian gravity. In a quantum description of matter a single motionless massive particle can in principle be in a superposition state of two spatially separated locations. This superposition state in gravity, or gravitational cat state, would lead to fluctuations in the Newtonian force exerted on a nearby test particle. The central quantity of importance for this inquiry is the energy density correlation. This corresponds to the noise kernel in stochastic gravity theory, evaluated in the weak field nonrelativistic limit. In this limit quantum fluctuations of the stress–energy tensor manifest as the fluctuations of the Newtonian force. We describe the properties of such a G2S system and present two ways of measuring the cat state for the Newtonian force, one by way of a classical probe, the other a quantum harmonic oscillator. Our findings include: (i) mass density fluctuations persist even in single particle systems, and they are of the same order of magnitude as the mean; (ii) a classical probe generically records a non-Markovian fluctuating force; (iii) a quantum probe interacting with the G2S system may undergo Rabi oscillations in a strong coupling regime. This simple prototypical gravitational quantum system could provide a robust testing ground to compare predictions from alternative quantum theories, since the results reported here are based on standard quantum mechanics and classical gravity. (paper)

  10. The Van Allen Probes mission

    CERN Document Server

    Burch, James

    2014-01-01

    This collection of articles provides broad and detailed information about NASA’s Van Allen Probes (formerly known as the Radiation Belt Storm Probes) twin-spacecraft Earth-orbiting mission. The mission has the objective of achieving predictive understanding of the dynamic, intense, energetic, dangerous, and presently unpredictable belts of energetic particles that are magnetically trapped in Earth’s space environment above the atmosphere. It documents the science of the radiation belts and the societal benefits of achieving predictive understanding. Detailed information is provided about the Van Allen Probes mission design, the spacecraft, the science investigations, and the onboard instrumentation that must all work together to make unprecedented measurements within a most unforgiving environment, the core of Earth’s most intense radiation regions.
 This volume is aimed at graduate students and researchers active in space science, solar-terrestrial interactions and studies of the up...

  11. Reducing Plasma Perturbations with Segmented Metal Shielding on Electrostatic Probes

    International Nuclear Information System (INIS)

    Staack, D.; Raitses, Y.; Fisch, N.J.

    2002-01-01

    Electrostatic probes are widely used to measure spatial plasma parameters in the quasi-neutral plasma created in Hall thrusters and similar E x B electric discharge devices. Significant perturbations of the plasma, induced by such probes, can mask the actual physics involved in operation of these devices. In an attempt to reduce these perturbations in Hall thrusters, the perturbations were examined by varying the component material, penetration distance, and residence time of various probe designs. This study leads us to a conclusion that secondary electron emission from insulator ceramic tubes of the probe can affect local changes of the plasma parameters causing plasma perturbations. A probe design, which consists of a segmented metal shielding of the probe insulator, is suggested to reduce these perturbations. This new probe design can be useful for plasma applications in which the electron temperature is sufficient to produce secondary electron emission by interaction of plasma electrons with dielectric materials

  12. Hard probes 2006 Asilomar

    CERN Multimedia

    2006-01-01

    "The second international conference on hard and electromagnetic probes of high-energy nuclear collisions was held June 9 to 16, 2006 at the Asilomar Conference grounds in Pacific Grove, California" (photo and 1/2 page)

  13. Adjustable Pitot Probe

    Science.gov (United States)

    Ashby, George C., Jr.; Robbins, W. Eugene; Horsley, Lewis A.

    1991-01-01

    Probe readily positionable in core of uniform flow in hypersonic wind tunnel. Formed of pair of mating cylindrical housings: transducer housing and pitot-tube housing. Pitot tube supported by adjustable wedge fairing attached to top of pitot-tube housing with semicircular foot. Probe adjusted both radially and circumferentially. In addition, pressure-sensing transducer cooled internally by water or other cooling fluid passing through annulus of cooling system.

  14. Project and construction of counting system for neutron probe

    International Nuclear Information System (INIS)

    Monteiro, W.P.

    1985-01-01

    A counting system was developed for coupling neutron probe aiming to register pulses produced by slow neutron interaction in the detector. The neutron probe consists of fast neutron source, thermal neutron detector, amplifier circuit and pulse counting circuit. The counting system is composed by counting circuit, timer and signal circuit. (M.C.K.)

  15. Building versatile bipartite probes for quantum metrology

    Science.gov (United States)

    Farace, Alessandro; De Pasquale, Antonella; Adesso, Gerardo; Giovannetti, Vittorio

    2016-01-01

    We consider bipartite systems as versatile probes for the estimation of transformations acting locally on one of the subsystems. We investigate what resources are required for the probes to offer a guaranteed level of metrological performance, when the latter is averaged over specific sets of local transformations. We quantify such a performance via the average skew information (AvSk), a convex quantity which we compute in closed form for bipartite states of arbitrary dimensions, and which is shown to be strongly dependent on the degree of local purity of the probes. Our analysis contrasts and complements the recent series of studies focused on the minimum, rather than the average, performance of bipartite probes in local estimation tasks, which was instead determined by quantum correlations other than entanglement. We provide explicit prescriptions to characterize the most reliable states maximizing the AvSk, and elucidate the role of state purity, separability and correlations in the classification of optimal probes. Our results can help in the identification of useful resources for sensing, estimation and discrimination applications when complete knowledge of the interaction mechanism realizing the local transformation is unavailable, and access to pure entangled probes is technologically limited.

  16. Building versatile bipartite probes for quantum metrology

    International Nuclear Information System (INIS)

    Farace, Alessandro; Pasquale, Antonella De; Giovannetti, Vittorio; Adesso, Gerardo

    2016-01-01

    We consider bipartite systems as versatile probes for the estimation of transformations acting locally on one of the subsystems. We investigate what resources are required for the probes to offer a guaranteed level of metrological performance, when the latter is averaged over specific sets of local transformations. We quantify such a performance via the average skew information (AvSk), a convex quantity which we compute in closed form for bipartite states of arbitrary dimensions, and which is shown to be strongly dependent on the degree of local purity of the probes. Our analysis contrasts and complements the recent series of studies focused on the minimum, rather than the average, performance of bipartite probes in local estimation tasks, which was instead determined by quantum correlations other than entanglement. We provide explicit prescriptions to characterize the most reliable states maximizing the AvSk, and elucidate the role of state purity, separability and correlations in the classification of optimal probes. Our results can help in the identification of useful resources for sensing, estimation and discrimination applications when complete knowledge of the interaction mechanism realizing the local transformation is unavailable, and access to pure entangled probes is technologically limited. (paper)

  17. The photostability of the commonly used biotin-4-fluorescein probe.

    Science.gov (United States)

    Haack, Richard A; Swift, Kerry M; Ruan, Qiaoqiao; Himmelsbach, Richard J; Tetin, Sergey Y

    2017-08-15

    Biotin-4-fluorescein (B4F) is a commonly used fluorescent probe for studying biotin-(strept)avidin interactions. During a characterization study of an anti-biotin antibody, using B4F as the probe, we noticed a discrepancy in the expected and experimentally determined number of biotin binding sites. Analytical testing showed that the biotin moiety in the probe undergoes a photosensitized oxidation to produce a mixture of biotin sulfoxides which has the potential to impact the quantitation of binding sites using this fluorescent probe. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Model for resonant plasma probe.

    Energy Technology Data Exchange (ETDEWEB)

    Warne, Larry Kevin; Johnson, William Arthur; Hebner, Gregory Albert; Jorgenson, Roy E.; Coats, Rebecca Sue

    2007-04-01

    This report constructs simple circuit models for a hairpin shaped resonant plasma probe. Effects of the plasma sheath region surrounding the wires making up the probe are determined. Electromagnetic simulations of the probe are compared to the circuit model results. The perturbing effects of the disc cavity in which the probe operates are also found.

  19. Magnetic nanostructures: radioactive probes and recent developments

    International Nuclear Information System (INIS)

    Prandolini, M J

    2006-01-01

    111 Cd probes using time-differential perturbed angular correlation (TDPAC), it was possible to distinguish the interaction of Cd probes located at various surface sites, i.e. atop terraces, within terraces, at steps and at corners. These experimental results are compared with the ground-state properties determined by ab initio density-functional theory. This article was invited by Professor S Washburn

  20. Innovative SPM Probes for Energy-Storage Science: MWCNT-Nanopipettes to Nanobattery Probes

    Science.gov (United States)

    Larson, Jonathan; Talin, Alec; Pearse, Alexander; Kozen, Alexander; Reutt-Robey, Janice

    As energy-storage materials and designs continue to advance, new tools are needed to direct and explore ion insertion/de-insertion at well-defined battery materials interfaces. Scanned probe tips, assembled from actual energy-storage materials, permit SPM measures of local cathode-anode (tip-sample) interactions, including ion transfer. We present examples of ``cathode'' MWCNT-terminated STM probe tips interacting with Li(s)/Si(111) anode substrates. The MWCNT tip functions as both SPM probe and Li-nanopipette,[1] for controlled transport and manipulation of Li. Local field conditions for lithium ionization and transfer are determined and compared to electrostatic models. Additional lithium metallic and oxide tips have been prepared by thin film deposition on conventional W tips, the latter of which effectively functions as a nanobattery. We demonstrate use of these novel probe materials in the local lithiation of low-index Si anode interfaces, probing local barriers for lithium insertion. Prospects and limitations of these novel SPM probes will be discussed. U.S. Department of Energy Award Number DESC0001160.

  1. Convective heat flow probe

    Science.gov (United States)

    Dunn, James C.; Hardee, Harry C.; Striker, Richard P.

    1985-01-01

    A convective heat flow probe device is provided which measures heat flow and fluid flow magnitude in the formation surrounding a borehole. The probe comprises an elongate housing adapted to be lowered down into the borehole; a plurality of heaters extending along the probe for heating the formation surrounding the borehole; a plurality of temperature sensors arranged around the periphery of the probe for measuring the temperature of the surrounding formation after heating thereof by the heater elements. The temperature sensors and heater elements are mounted in a plurality of separate heater pads which are supported by the housing and which are adapted to be radially expanded into firm engagement with the walls of the borehole. The heat supplied by the heater elements and the temperatures measured by the temperature sensors are monitored and used in providing the desired measurements. The outer peripheral surfaces of the heater pads are configured as segments of a cylinder and form a full cylinder when taken together. A plurality of temperature sensors are located on each pad so as to extend along the length and across the width thereof, with a heating element being located in each pad beneath the temperature sensors. An expansion mechanism driven by a clamping motor provides expansion and retraction of the heater pads and expandable packer-type seals are provided along the probe above and below the heater pads.

  2. Theory of NMR probe design

    International Nuclear Information System (INIS)

    Schnall, M.D.

    1988-01-01

    The NMR probe is the intrinsic part of the NMR system which allows transmission of a stimulus to a sample and the reception of a resulting signal from a sample. NMR probes are used in both imaging and spectroscopy. Optimal probe design is important to the production of adequate signal/moise. It is important for anyone using NMR techniques to understand how NMR probes work and how to optimize probe design

  3. Probes for edge plasma studies of TFTR (invited)

    International Nuclear Information System (INIS)

    Manos, D.M.; Budny, R.V.; Kilpatrick, S.; Stangeby, P.; Zweben, S.

    1986-01-01

    Tokamak fusion test reactor (TFTR) probes are designed to study the interaction of the plasma with material surfaces such as the wall and limiters, and to study the transport of particles and energy between the core and edge. Present probe heads have evolved from prototypes in Princeton large torus (PLT), poloidal divertor experiment (PDX) [Princeton BETA experiment (PBX)], and the initial phase of TFTR operation. The newest heads are capable of making several simultaneous measurements and include Langmuir probes, heat flux probes, magnetic coils, rotating calorimeter fast ion probes, and sample exposure specimens. This paper describes these probe heads and presents some of the data they and their prototypes have acquired. The paper emphasizes measurement of transient plasma effects such as fast ion loss during auxiliary heating, the evolution of the edge plasma during heating, compression, and free expansion, and fluctuations in the edge plasma

  4. Protein recognition by a pattern-generating fluorescent molecular probe

    Science.gov (United States)

    Pode, Zohar; Peri-Naor, Ronny; Georgeson, Joseph M.; Ilani, Tal; Kiss, Vladimir; Unger, Tamar; Markus, Barak; Barr, Haim M.; Motiei, Leila; Margulies, David

    2017-12-01

    Fluorescent molecular probes have become valuable tools in protein research; however, the current methods for using these probes are less suitable for analysing specific populations of proteins in their native environment. In this study, we address this gap by developing a unimolecular fluorescent probe that combines the properties of small-molecule-based probes and cross-reactive sensor arrays (the so-called chemical 'noses/tongues'). On the one hand, the probe can detect different proteins by generating unique identification (ID) patterns, akin to cross-reactive arrays. On the other hand, its unimolecular scaffold and selective binding enable this ID-generating probe to identify combinations of specific protein families within complex mixtures and to discriminate among isoforms in living cells, where macroscopic arrays cannot access. The ability to recycle the molecular device and use it to track several binding interactions simultaneously further demonstrates how this approach could expand the fluorescent toolbox currently used to detect and image proteins.

  5. Probes for dark matter physics

    Science.gov (United States)

    Khlopov, Maxim Yu.

    The existence of cosmological dark matter is in the bedrock of the modern cosmology. The dark matter is assumed to be nonbaryonic and consists of new stable particles. Weakly Interacting Massive Particle (WIMP) miracle appeals to search for neutral stable weakly interacting particles in underground experiments by their nuclear recoil and at colliders by missing energy and momentum, which they carry out. However, the lack of WIMP effects in their direct underground searches and at colliders can appeal to other forms of dark matter candidates. These candidates may be weakly interacting slim particles, superweakly interacting particles, or composite dark matter, in which new particles are bound. Their existence should lead to cosmological effects that can find probes in the astrophysical data. However, if composite dark matter contains stable electrically charged leptons and quarks bound by ordinary Coulomb interaction in elusive dark atoms, these charged constituents of dark atoms can be the subject of direct experimental test at the colliders. The models, predicting stable particles with charge ‑ 2 without stable particles with charges + 1 and ‑ 1 can avoid severe constraints on anomalous isotopes of light elements and provide solution for the puzzles of dark matter searches. In such models, the excessive ‑ 2 charged particles are bound with primordial helium in O-helium atoms, maintaining specific nuclear-interacting form of the dark matter. The successful development of composite dark matter scenarios appeals for experimental search for doubly charged constituents of dark atoms, making experimental search for exotic stable double charged particles experimentum crucis for dark atoms of composite dark matter.

  6. Optical Probes for Neurobiological Sensing and Imaging.

    Science.gov (United States)

    Kim, Eric H; Chin, Gregory; Rong, Guoxin; Poskanzer, Kira E; Clark, Heather A

    2018-04-13

    Fluorescent nanosensors and molecular probes are next-generation tools for imaging chemical signaling inside and between cells. Electrophysiology has long been considered the gold standard in elucidating neural dynamics with high temporal resolution and precision, particularly on the single-cell level. However, electrode-based techniques face challenges in illuminating the specific chemicals involved in neural cell activation with adequate spatial information. Measuring chemical dynamics is of fundamental importance to better understand synergistic interactions between neurons as well as interactions between neurons and non-neuronal cells. Over the past decade, significant technological advances in optical probes and imaging methods have enabled entirely new possibilities for studying neural cells and circuits at the chemical level. These optical imaging modalities have shown promise for combining chemical, temporal, and spatial information. This potential makes them ideal candidates to unravel the complex neural interactions at multiple scales in the brain, which could be complemented by traditional electrophysiological methods to obtain a full spatiotemporal picture of neurochemical dynamics. Despite the potential, only a handful of probe candidates have been utilized to provide detailed chemical information in the brain. To date, most live imaging and chemical mapping studies rely on fluorescent molecular indicators to report intracellular calcium (Ca 2+ ) dynamics, which correlates with neuronal activity. Methodological advances for monitoring a full array of chemicals in the brain with improved spatial, temporal, and chemical resolution will thus enable mapping of neurochemical circuits with finer precision. On the basis of numerous studies in this exciting field, we review the current efforts to develop and apply a palette of optical probes and nanosensors for chemical sensing in the brain. There is a strong impetus to further develop technologies capable of

  7. K+-nucleus interaction

    International Nuclear Information System (INIS)

    Gibbs, W.R.

    1984-01-01

    The K + -nucleus system is reviewed and comparison with data is made. The principal conclusions are that the theoretical uncertainties in relating the K + -nucleus interaction to the K + -nucleon interaction are very small and hence the positive kaon makes an excellent probe of the nucleus. It is suggested that this particle may be more sensitive to non-nucleonic degrees of freedom (especially quarks) than classical probes

  8. The Sheath-less Planar Langmuir Probe

    Science.gov (United States)

    Cooke, D. L.

    2017-12-01

    The Langmuir probe is one of the oldest plasma diagnostics, provided the plasma density and species temperature from analysis of a current-voltage curve as the voltage is swept over a practically chosen range. The analysis depends on a knowledge or theory of the many factors that influence the current-voltage curve including, probe shape, size, nearby perturbations, and the voltage reference. For applications in Low Earth Orbit, the Planar Langmuir Probe, PLP, is an attractive geometry because the ram ion current is very constant over many Volts of a sweep, allowing the ion density and electron temperature to be determined independently with the same instrument, at different points on the sweep. However, when the physical voltage reference is itself small and electrically floating as with a small spacecraft, the spacecraft and probe system become a double probe where the current collection theory depends on the interaction of the spacecraft with the plasma which is generally not as simple as the probe itself. The Sheath-less PLP, SPLP, interlaces on a single ram facing surface, two variably biased probe elements, broken into many small and intertwined segments on a scale smaller than the plasma Debye length. The SPLP is electrically isolated from the rest of the spacecraft. For relative bias potentials of a few volts, the ion current to all segments of each element will be constant, while the electron currents will vary as a function of the element potential and the electron temperature. Because the segments are small, intertwined, and floating, the assembly will always present the same floating potential to the plasma, with minimal growth as a function of voltage, thus sheath-less and still planar. This concept has been modelled with Nascap, and tested with a physical model inserted into a Low Earth Orbit-like chamber plasma. Results will be presented.

  9. Nuclear probes of fundamental symmetries

    International Nuclear Information System (INIS)

    Adelberger, E.G.

    1983-01-01

    Nuclear experiments which probe the parity (P) and time-reversal (T) symmetries and lepton-number conservation are reviewed. The P-violating NN interaction, studied in the NN system and in light nuclei, provides an unique window on ΔS=0 hadronic weak processes. Results are in accord with expectations. Sensitive searches for T-violation via detailed balance, T-odd correlations in γ and β-decay, and a possible neutron electric dipole moment (EDM) are discussed. No T-violation is observed. The EDM limit is almost good enough to eliminate one of the leading theoretical explanations for CP violation. Experimental studies of double β-decay are reviewed. Although ββ nu nu decay has been convincingly detected in geochemical experiments there is no evidence for the lepton number violating ββ decay mode

  10. New Fluorescence Probes for Biomolecules

    Directory of Open Access Journals (Sweden)

    Katarzyna Jurek

    2015-07-01

    Full Text Available Steady state fluorescence measurements have been used for the investigation of interaction between the bovine serum albumin (BSA and fluorescence probes: 3-hydroxy-2,4- bis[(3-methyl-1,3-benzoxazol-2(3H-ylidenemethyl]cyclobut-2-en-1-one (SQ6, 3-hydroxy- 2,4-bis[(3-methyl-1,3-benzothiazol-2(3H-ylidenemethyl]cyclobut-2-en-1-one (SQ7 and 3-hydroxy-2,4-bis[(1,3,3-trimethyl-1,3-dihydro-2H-indol-2-ylidenemethyl]cyclobut-2-en-1-one (SQ8. The binding constant between bovine serum albumin and squarine dyes has been determined by using both the Benesi-Hildebrand and Stern-Volmer equations. The negative value of free energy change indicates the existence of a spontaneous complexation process of BSA with squarine dyes.

  11. One-Probe Search

    DEFF Research Database (Denmark)

    Östlin, Anna; Pagh, Rasmus

    2002-01-01

    We consider dictionaries that perform lookups by probing a single word of memory, knowing only the size of the data structure. We describe a randomized dictionary where a lookup returns the correct answer with probability 1 - e, and otherwise returns don't know. The lookup procedure uses an expan...

  12. Probing the Solar System

    Science.gov (United States)

    Wilkinson, John

    2013-01-01

    Humans have always had the vision to one day live on other planets. This vision existed even before the first person was put into orbit. Since the early space missions of putting humans into orbit around Earth, many advances have been made in space technology. We have now sent many space probes deep into the Solar system to explore the planets and…

  13. Probing the Solar Interior

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 3; Issue 3. Probing the Solar Interior Hearing the Heartbeats of the Sun. Ashok Ambastha. General ... Author Affiliations. Ashok Ambastha1. Joint In-Charge Udaipur Solar Observatory Physical Research laboratory P.O. Box No. 198 Udaipur 313 001, India ...

  14. Flexible position probe assembly

    International Nuclear Information System (INIS)

    Schmitz, J.J.

    1977-01-01

    The combination of a plurality of tubular transducer sections and a flexible supporting member extending through the tubular transducer sections forms a flexible elongated probe of a design suitable for monitoring the level of an element, such as a nuclear magnetically permeable control rod or liquid. 3 claims, 23 figures

  15. EDITORIAL: Probing the nanoworld Probing the nanoworld

    Science.gov (United States)

    Miles, Mervyn

    2009-10-01

    In nanotechnology, it is the unique properties arising from nanometre-scale structures that lead not only to their technological importance but also to a better understanding of the underlying science. Over the last twenty years, material properties at the nanoscale have been dominated by the properties of carbon in the form of the C60 molecule, single- and multi-wall carbon nanotubes, nanodiamonds, and recently graphene. During this period, research published in the journal Nanotechnology has revealed the amazing mechanical properties of such materials as well as their remarkable electronic properties with the promise of new devices. Furthermore, nanoparticles, nanotubes, nanorods, and nanowires from metals and dielectrics have been characterized for their electronic, mechanical, optical, chemical and catalytic properties. Scanning probe microscopy (SPM) has become the main characterization technique and atomic force microscopy (AFM) the most frequently used SPM. Over the past twenty years, SPM techniques that were previously experimental in nature have become routine. At the same time, investigations using AFM continue to yield impressive results that demonstrate the great potential of this powerful imaging tool, particularly in close to physiological conditions. In this special issue a collaboration of researchers in Europe report the use of AFM to provide high-resolution topographical images of individual carbon nanotubes immobilized on various biological membranes, including a nuclear membrane for the first time (Lamprecht C et al 2009 Nanotechnology 20 434001). Other SPM developments such as high-speed AFM appear to be making a transition from specialist laboratories to the mainstream, and perhaps the same may be said for non-contact AFM. Looking to the future, characterisation techniques involving SPM and spectroscopy, such as tip-enhanced Raman spectroscopy, could emerge as everyday methods. In all these advanced techniques, routinely available probes will

  16. Numerical simulations for quantitative analysis of electrostatic interaction between atomic force microscopy probe and an embedded electrode within a thin dielectric: meshing optimization, sensitivity to potential distribution and impact of cantilever contribution

    Science.gov (United States)

    Azib, M.; Baudoin, F.; Binaud, N.; Villeneuve-Faure, C.; Bugarin, F.; Segonds, S.; Teyssedre, G.

    2018-04-01

    Recent experimental results demonstrated that an electrostatic force distance curve (EFDC) can be used for space charge probing in thin dielectric layers. A main advantage of the method is claimed to be its sensitivity to charge localization, which, however, needs to be substantiated by numerical simulations. In this paper, we have developed a model which permits us to compute an EFDC accurately by using the most sophisticated and accurate geometry for the atomic force microscopy probe. To avoid simplifications and in order to reproduce experimental conditions, the EFDC has been simulated for a system constituted of a polarized electrode embedded in a thin dielectric layer (SiN x ). The individual contributions of forces on the tip and on the cantilever have been analyzed separately to account for possible artefacts. The EFDC sensitivity to potential distribution is studied through the change in electrode shape, namely the width and the depth. Finally, the numerical results have been compared with experimental data.

  17. Bioresponsive probes for molecular imaging:Concepts and in vivo applications

    OpenAIRE

    Duijnhoven, van, SMJ Sander; Robillard, MS Marc; Langereis, S Sander; Grüll, H Holger

    2015-01-01

    Molecular imaging is a powerful tool to visualize and characterize biological processes at the cellular and molecular level in vivo. In most molecular imaging approaches, probes are used to bind to disease-specific biomarkers highlighting disease target sites. In recent years, a new subset of molecular imaging probes, known as bioresponsive molecular probes, has been developed. These probes generally benefit from signal enhancement at the site of interaction with its target. There are mainly ...

  18. Modular Rake of Pitot Probes

    Science.gov (United States)

    Dunlap, Timothy A.; Henry, Michael W.; Homyk, Raymond P.

    2004-01-01

    The figure presents selected views of a modular rake of 17 pitot probes for measuring both transient and steady-state pressures in a supersonic wind tunnel. In addition to pitot tubes visible in the figure, the probe modules contain (1) high-frequency dynamic-pressure transducers connected through wires to remote monitoring circuitry and (2) flow passages that lead to tubes that, in turn, lead to remote steady-state pressure transducers. Prior pitot-probe rakes were fabricated as unitary structures, into which the individual pitot probes were brazed. Repair or replacement of individual probes was difficult, costly, and time-consuming because (1) it was necessary to remove entire rakes in order to unbraze individual malfunctioning probes and (2) the heat of unbrazing a failed probe and of brazing a new probe in place could damage adjacent probes. In contrast, the modules in the present probe are designed to be relatively quickly and easily replaceable with no heating and, in many cases, without need for removal of the entire rake from the wind tunnel. To remove a malfunctioning probe, one first removes a screw-mounted V-cross-section cover that holds the probe and adjacent probes in place. Then one removes a screw-mounted cover plate to gain access to the steady-state pressure tubes and dynamicpressure wires. Next, one disconnects the tube and wires of the affected probe. Finally, one installs a new probe in the reverse of the aforementioned sequence. The wire connections can be made by soldering, but to facilitate removal and installation, they can be made via miniature plugs and sockets. The connections between the probe flow passages and the tubes leading to the remote pressure sensors can be made by use of any of a variety of readily available flexible tubes that can be easily pulled off and slid back on for removal and installation, respectively.

  19. Heavy ion beam probing

    International Nuclear Information System (INIS)

    Hickok, R.L.

    1980-07-01

    This report consists of the notes distributed to the participants at the IEEE Mini-Course on Modern Plasma Diagnostics that was held in Madison, Wisconsin in May 1980. It presents an overview of Heavy Ion Beam Probing that briefly describes the principles and discuss the types of measurements that can be made. The problems associated with implementing beam probes are noted, possible variations are described, estimated costs of present day systems, and the scaling requirements for large plasma devices are presented. The final chapter illustrates typical results that have been obtained on a variety of plasma devices. No detailed calculations are included in the report, but a list of references that will provide more detailed information is included

  20. Gravity Probe B Inspection

    Science.gov (United States)

    2000-01-01

    The space vehicle Gravity Probe B (GP-B) is the relativity experiment developed at Stanford University to test two extraordinary predictions of Albert Einstein's general theory of relativity. The experiment will measure, very precisely, the expected tiny changes in the direction of the spin axes of four gyroscopes contained in an Earth-orbiting satellite at a 400-mile altitude. So free are the gyroscopes from disturbance that they will provide an almost perfect space-time reference system. They will measure how space and time are very slightly warped by the presence of the Earth, and, more profoundly, how the Earth's rotation very slightly drags space-time around with it. These effects, though small for the Earth, have far-reaching implications for the nature of matter and the structure of the Universe. GP-B is among the most thoroughly researched programs ever undertaken by NASA. This is the story of a scientific quest in which physicists and engineers have collaborated closely over many years. Inspired by their quest, they have invented a whole range of technologies that are already enlivening other branches of science and engineering. In this photograph, engineer Gary Reynolds is inspecting the inside of the probe neck during probe thermal repairs. GP-B is scheduled for launch in April 2004 and managed for NASA by the Marshall Space Flight Center. Development of the GP-B is the responsibility of Stanford University along with major subcontractor Lockheed Martin Corporation. (Image credit to Russ Leese, Gravity Probe B, Stanford University)

  1. Induced current heating probe

    International Nuclear Information System (INIS)

    Thatcher, G.; Ferguson, B.G.; Winstanley, J.P.

    1984-01-01

    An induced current heating probe is of thimble form and has an outer conducting sheath and a water flooded flux-generating unit formed from a stack of ferrite rings coaxially disposed in the sheath. The energising coil is made of solid wire which connects at one end with a coaxial water current tube and at the other end with the sheath. The stack of ferrite rings may include non-magnetic insulating rings which help to shape the flux. (author)

  2. Evaluation of Apple Maturity with Two Types of Dielectric Probes

    Directory of Open Access Journals (Sweden)

    Marcin Kafarski

    2018-01-01

    Full Text Available The observed dielectric spectrum of ripe apples in the last period of shelf-life was analyzed using a multipole dielectric relaxation model, which assumes three active relaxation processes: primary α-process (water relaxation and two secondary processes caused by solid-water-ion interactions α’ (bound water relaxations, as well as β’ (Maxwell-Wagner effect. The performance of two designs of the dielectric probe was compared: a classical coaxial open-ended probe (OE probe and an open-ended probe with a prolonged central conductor in a form of an antenna (OE-A-probe. The OE-A probe increases the measurement volume and consequently extends the range of applications to other materials, like granulated agricultural products, soils, or liquid suspensions. However, its measurement frequency range is limited as compared to the OE probe because, above 1.5 GHz, the probe with the antenna generates higher propagation modes and the applied calibrations and calculations are not sufficient. It was shown that data from measurements using the OE-A probe gave slightly stronger correlations with apples’ quality parameters than using the typical OE probe. Additionally, we have compared twelve multipole fitting models with different combinations of poles (eight three-pole and four two-pole models. It was shown that the best fit is obtained using a two-pole model for data collected for the OE-A probe and a three-pole model for the OE probe, using only Cole-Cole poles in both cases.

  3. Einstein Inflationary Probe (EIP)

    Science.gov (United States)

    Hinshaw, Gary

    2004-01-01

    I will discuss plans to develop a concept for the Einstein Inflation Probe: a mission to detect gravity waves from inflation via the unique signature they impart to the cosmic microwave background (CMB) polarization. A sensitive CMB polarization satellite may be the only way to probe physics at the grand-unified theory (GUT) scale, exceeding by 12 orders of magnitude the energies studied at the Large Hadron Collider. A detection of gravity waves would represent a remarkable confirmation of the inflationary paradigm and set the energy scale at which inflation occurred when the universe was a fraction of a second old. Even a strong upper limit to the gravity wave amplitude would be significant, ruling out many common models of inflation, and pointing to inflation occurring at much lower energy, if at all. Measuring gravity waves via the CMB polarization will be challenging. We will undertake a comprehensive study to identify the critical scientific requirements for the mission and their derived instrumental performance requirements. At the core of the study will be an assessment of what is scientifically and experimentally optimal within the scope and purpose of the Einstein Inflation Probe.

  4. Nine New Fluorescent Probes

    Science.gov (United States)

    Lin, Tsung-I.; Jovanovic, Misa V.; Dowben, Robert M.

    1989-06-01

    Absorption and fluorescence spectroscopic studies are reported here for nine new fluorescent probes recently synthesized in our laboratories: four pyrene derivatives with substituents of (i) 1,3-diacetoxy-6,8-dichlorosulfonyl, (ii) 1,3-dihydroxy-6,8-disodiumsulfonate, (iii) 1,3-disodiumsulfonate, and (iv) l-ethoxy-3,6,8-trisodiumsulfonate groups, and five [7-julolidino] coumarin derivatives with substituents of (v) 3-carboxylate-4-methyl, (vi) 3- methylcarboxylate, (vii) 3-acetate-4-methyl, (viii) 3-propionate-4-methyl, and (ix) 3-sulfonate-4-methyl groups. Pyrene compounds i and ii and coumarin compounds v and vi exhibit interesting absorbance and fluorescence properties: their absorption maxima are red shifted compared to the parent compound to the blue-green region, and the band width broadens considerably. All four blue-absorbing dyes fluoresce intensely in the green region, and the two pyrene compounds emit at such long wavelengths without formation of excimers. The fluorescence properties of these compounds are quite environment-sensitive: considerable spectral shifts and fluorescence intensity changes have been observed in the pH range from 3 to 10 and in a wide variety of polar and hydrophobic solvents with vastly different dielectric constants. The high extinction and fluorescence quantum yield of these probes make them ideal fluorescent labeling reagents for proteins, antibodies, nucleic acids, and cellular organelles. The pH and hydrophobicity-dependent fluorescence changes can be utilized as optical pH and/or hydrophobicity indicators for mapping environmental difference in various cellular components in a single cell. Since all nine probes absorb in the UV, but emit at different wavelengths in the visible, these two groups of compounds offer an advantage of utilizing a single monochromatic light source (e.g., a nitrogen laser) to achieve multi-wavelength detection for flow cytometry application. As a first step to explore potential application in

  5. Hyper-Ramsey spectroscopy with probe-laser-intensity fluctuations

    Science.gov (United States)

    Beloy, K.

    2018-03-01

    We examine the influence of probe-laser-intensity fluctuations on hyper-Ramsey spectroscopy. We assume, as is appropriate for relevant cases of interest, that the probe-laser intensity I determines both the Rabi frequency (∝√{I } ) and the frequency shift to the atomic transition (∝I ) during probe-laser interactions with the atom. The spectroscopic signal depends on these two quantities that covary with fluctuations in the probe-laser intensity. Introducing a simple model for the fluctuations, we find that the signature robustness of the hyper-Ramsey method can be compromised. Taking the Yb+ electric octupole clock transition as an example, we quantify the clock error under different levels of probe-laser-intensity fluctuations.

  6. Wearable probes for service design

    DEFF Research Database (Denmark)

    Mullane, Aaron; Laaksolahti, Jarmo Matti; Svanæs, Dag

    2014-01-01

    Probes are used as a design method in user-centred design to allow end-users to inform design by collecting data from their lives. Probes are potentially useful in service innovation, but current probing methods require users to interrupt their activity and are consequently not ideal for use...... by service employees in reflecting on the delivery of a service. In this paper, we present the ‘wearable probe’, a probe concept that captures sensor data without distracting service employees. Data captured by the probe can be used by the service employees to reflect and co-reflect on the service journey......, helping to identify opportunities for service evolution and innovation....

  7. International Conference on Spin Observables of Nuclear Probes

    CERN Document Server

    Goodman, Charles; Walker, George; Spin Observables of Nuclear Probes

    1988-01-01

    The proceedings of the "International Conference on Spin Observables of Nuclear Probes" are presented in this volume. This conference was held in Telluride, Colorado, March 14 -17, 1988, and was the fourth in the Telluride series of nuclear physics conferences. A continuing theme in the Telluride conference series has been the complementarity of various intermediate-energy projectiles for elucidating the nucleon-nucleon interaction and nuclear structure. Earlier conferences have contributed significantly to an understanding of spin currents in nuclei, in particular the distribution of Gamow-Teller strength using charge-exchange reactions. The previous conference on "Antinucleon and Nucleon Nucleus Interactions" compared nuclear information from tra­ tional probes to recent results from antinucleon reactions. The 1988 conference on Spin Observables of Nuclear Probes, put special emphasis on spin observables and brought together experts using spin information to probe nuclear structure. Spin observabl...

  8. Recombinant phage probes for Listeria monocytogenes

    Energy Technology Data Exchange (ETDEWEB)

    Carnazza, S; Gioffre, G; Felici, F; Guglielmino, S [Department of Microbiological, Genetic and Molecular Sciences, University of Messina, Messina (Italy)

    2007-10-03

    Monitoring of food and environmental samples for biological threats, such as Listeria monocytogenes, requires probes that specifically bind biological agents and ensure their immediate and efficient detection. There is a need for robust and inexpensive affinity probes as an alternative to antibodies. These probes may be recruited from random peptide libraries displayed on filamentous phage. In this study, we selected from two phage peptide libraries phage clones displaying peptides capable of specific and strong binding to the L. monocytogenes cell surface. The ability of isolated phage clones to interact specifically with L. monocytogenes was demonstrated using enzyme-linked immunosorbent assay (ELISA) and confirmed by co-precipitation assay. We also assessed the sensitivity of phage-bacteria binding by PCR on phage-captured Listeria cells, which could be detected at a concentration of 10{sup 4} cells ml{sup -1}. In addition, as proof-of-concept, we tested the possibility of immobilizing the affinity-selected phages to a putative biosensor surface. The quality of phage deposition was monitored by ELISA and fluorescent microscopy. Phage-bacterial binding was confirmed by high power optical phase contrast microscopy. Overall, the results of this work validate the concept of affinity-selected recombinant filamentous phages as probes for detecting and monitoring bacterial agents under any conditions that warrant their recognition, including in food products.

  9. Recombinant phage probes for Listeria monocytogenes

    Science.gov (United States)

    Carnazza, S.; Gioffrè, G.; Felici, F.; Guglielmino, S.

    2007-10-01

    Monitoring of food and environmental samples for biological threats, such as Listeria monocytogenes, requires probes that specifically bind biological agents and ensure their immediate and efficient detection. There is a need for robust and inexpensive affinity probes as an alternative to antibodies. These probes may be recruited from random peptide libraries displayed on filamentous phage. In this study, we selected from two phage peptide libraries phage clones displaying peptides capable of specific and strong binding to the L. monocytogenes cell surface. The ability of isolated phage clones to interact specifically with L. monocytogenes was demonstrated using enzyme-linked immunosorbent assay (ELISA) and confirmed by co-precipitation assay. We also assessed the sensitivity of phage-bacteria binding by PCR on phage-captured Listeria cells, which could be detected at a concentration of 104 cells ml-1. In addition, as proof-of-concept, we tested the possibility of immobilizing the affinity-selected phages to a putative biosensor surface. The quality of phage deposition was monitored by ELISA and fluorescent microscopy. Phage-bacterial binding was confirmed by high power optical phase contrast microscopy. Overall, the results of this work validate the concept of affinity-selected recombinant filamentous phages as probes for detecting and monitoring bacterial agents under any conditions that warrant their recognition, including in food products.

  10. The solar probe mission

    International Nuclear Information System (INIS)

    Feldman, W.C.; Anderson, J.; Bohlin, J.D.; Burlaga, L.F.; Farquhar, R.; Gloeckler, G.; Goldstein, B.E.; Harvey, J.W.; Holzer, T.E.; Jones, W.V.; Kellogg, P.J.; Krimigis, S.M.; Kundu, M.R.; Lazarus, A.J.; Mellott, M.M.; Parker, E.N.; Rosner, R.; Rottman, G.J.; Slavin, J.A.; Suess, S.T.; Tsurutani, B.T.; Woo, R.T.; Zwickl, R.D.

    1990-01-01

    The Solar Probe will deliver a 133.5 kg science payload into a 4 R s perihelion solar polar orbit (with the first perihelion passage in 2004) to explore in situ one of the last frontiers in the solar system---the solar corona. This mission is both affordable and technologically feasible. Using a payload of 12 (predominantly particles and fields) scientific experiments, it will be possible to answer many long-standing, fundamental problems concerning the structure and dynamics of the outer solar atmosphere, including the acceleration, storage, and transport of energetic particles near the Sun and in the inner ( s ) heliosphere

  11. Mobile Probing Kit

    DEFF Research Database (Denmark)

    Larsen, Jakob Eg; Sørensen, Lene Tolstrup; Sørensen, J.K.

    2007-01-01

    Mobile Probing Kit is a low tech and low cost methodology for obtaining inspiration and insights into user needs, requirements and ideas in the early phases of a system's development process. The methodology is developed to identify user needs, requirements and ideas among knowledge workers...... characterized as being highly nomadic and thus potential users of mobile and ubiquitous technologies. The methodology has been applied in the 1ST MAGNET Beyond project in order to obtain user needs and requirements in the process of developing pilot services. We report on the initial findings from applying...

  12. A new theoretical probe for the magnetic force microscope

    Energy Technology Data Exchange (ETDEWEB)

    Windmill, J.F.C. E-mail: jwindmill@plymouth.ac.uk; Clegg, W.W.; Jenkins, D.F.L.; Davey, P.J

    2001-05-01

    The magnetic force microscope (MFM) is established as a valuable tool for the analysis of magnetic structures. The standard design of MFM incorporates a silicon tip coated with a magnetic material. However, these tips are subject to several inherent problems, e.g. changing characteristics over time due to damage or magnetic hysteresis. A new theoretical electromagnetic MFM probe is introduced here. Although electromagnetic MFM has been discussed before by Zhou et al. (J. Vac. Sci. Technol. A 17 (1999) 2233), the design presented here is a different approach. Two different probe iterations and their magnetic field intensity distribution are modelled. The probe imaging capability is compared using the reciprocity principle (Wright and Hill, Appl. Phys. Lett. 68 (1996) 1726) to image the simulated force interaction between a sample and the probe fields. Thus, images of a sample's magnetic distribution are produced by the convolution of the different probe gradient field distributions and the sample magnetisation. Both perpendicular and longitudinal magnetisation patterns were simulated with the different probe iterations. This clearly showed the improvement of the second probe iteration, particularly for longitudinal patterns. The practical use of the new probe is also discussed, and future work outlined.

  13. Electroweak interactions in nuclei

    International Nuclear Information System (INIS)

    Henley, E.M.

    1984-06-01

    Topics include: introduction to electroweak theory; the Weinberg-Salam theory for leptons; the Weinberg-Salam theory for hadrons-the GIM mechanism; electron scattering as a probe of the electroweak interaction (observation of PV, the weak interaction for nucleons, and parity violation in atoms); and time reversed invariance and electric dipole moments of nucleons, nuclei, and atoms. 52 references

  14. Neutral helium beam probe

    Science.gov (United States)

    Karim, Rezwanul

    1999-10-01

    This article discusses the development of a code where diagnostic neutral helium beam can be used as a probe. The code solves numerically the evolution of the population densities of helium atoms at their several different energy levels as the beam propagates through the plasma. The collisional radiative model has been utilized in this numerical calculation. The spatial dependence of the metastable states of neutral helium atom, as obtained in this numerical analysis, offers a possible diagnostic tool for tokamak plasma. The spatial evolution for several hypothetical plasma conditions was tested. Simulation routines were also run with the plasma parameters (density and temperature profiles) similar to a shot in the Princeton beta experiment modified (PBX-M) tokamak and a shot in Tokamak Fusion Test Reactor tokamak. A comparison between the simulation result and the experimentally obtained data (for each of these two shots) is presented. A good correlation in such comparisons for a number of such shots can establish the accurateness and usefulness of this probe. The result can possibly be extended for other plasma machines and for various plasma conditions in those machines.

  15. Micro- and nanodevices integrated with biomolecular probes.

    Science.gov (United States)

    Alapan, Yunus; Icoz, Kutay; Gurkan, Umut A

    2015-12-01

    Understanding how biomolecules, proteins and cells interact with their surroundings and other biological entities has become the fundamental design criterion for most biomedical micro- and nanodevices. Advances in biology, medicine, and nanofabrication technologies complement each other and allow us to engineer new tools based on biomolecules utilized as probes. Engineered micro/nanosystems and biomolecules in nature have remarkably robust compatibility in terms of function, size, and physical properties. This article presents the state of the art in micro- and nanoscale devices designed and fabricated with biomolecular probes as their vital constituents. General design and fabrication concepts are presented and three major platform technologies are highlighted: microcantilevers, micro/nanopillars, and microfluidics. Overview of each technology, typical fabrication details, and application areas are presented by emphasizing significant achievements, current challenges, and future opportunities. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Probing surface magnetism with ion beams

    International Nuclear Information System (INIS)

    Winter, H.

    2007-01-01

    Ion beams can be used to probe magnetic properties of surfaces by a variety of different methods. Important features of these methods are related to trajectories of atomic projectiles scattered from the surface of a solid target and to the electronic interaction mechanisms in the surface region. Both items provide under specific conditions a high sensitivity for the detection of magnetic properties in the region at the topmost layer of surface atoms. This holds in particular for scattering under planar surface channeling conditions, where under grazing impact atoms or ions are reflected specularly from the surface without penetration into the subsurface region. Two different types of methods are employed based on the detection of the spin polarization of emitted or captured electrons and on spin blocking effects for capture into atomic terms. These techniques allow one to probe the long range and short range magnetic order in the surface region

  17. Protease-activated quantum dot probes

    International Nuclear Information System (INIS)

    Chang, Emmanuel; Miller, Jordan S.; Sun, Jiantang; Yu, William W.; Colvin, Vicki L.; Drezek, Rebekah; West, Jennifer L.

    2005-01-01

    We have developed a novel nanoparticulate luminescent probe with inherent signal amplification upon interaction with a targeted proteolytic enzyme. This construct may be useful for imaging in cancer detection and diagnosis. In this system, quantum dots (QDs) are bound to gold nanoparticles (AuNPs) via a proteolytically degradable peptide sequence to non-radiatively suppress luminescence. A 71% reduction in luminescence was achieved with conjugation of AuNPs to QDs. Release of AuNPs by peptide cleavage restores radiative QD photoluminescence. Initial studies observed a 52% rise in luminescence over 47 h of exposure to 0.2 mg/mL collagenase. These probes can be customized for targeted degradation simply by changing the sequence of the peptide linker

  18. Label-free biosensing with functionalized nanopipette probes

    OpenAIRE

    Umehara, Senkei; Karhanek, Miloslav; Davis, Ronald W.; Pourmand, Nader

    2009-01-01

    Nanopipette technology can uniquely identify biomolecules such as proteins based on differences in size, shape, and electrical charge. These differences are determined by the detection of changes in ionic current as the proteins interact with the nanopipette tip coated with probe molecules. Here we show that electrostatic, biotin-streptavidin, and antibody-antigen interactions on the nanopipette tip surface affect ionic current flowing through a 50-nm pore. Highly charged polymers interacting...

  19. The Gravity Probe B gyroscope

    International Nuclear Information System (INIS)

    Buchman, S; Lipa, J A; Keiser, G M; Muhlfelder, B; Turneaure, J P

    2015-01-01

    The Gravity Probe B (GP-B) gyroscope, a unique cryogenically operated mechanical sensor, was used on-orbit to independently test two predictions of general relativity (GR). Here, we describe the development and performance of the GP-B gyroscope, its geometry and fabrication, spin-up and vacuum approach, magnetic considerations, and static charge management. The history of electrically suspended gyroscopes puts the current work in context. Fabrication and ground testing of the GP-B gyroscope are detailed, followed by a review of on-orbit initialization, calibration, operation, and performance. We find that the performance was degraded relative to the mission goals, but was still sufficient to provide excellent new tests of GR. The degradation is partially due to the existence of gyroscope torques due to an unanticipated interaction between patch potentials on the rotor and the housing. We discuss these patch potentials and describe the effect of related torques on gyro drift. It was essential to include models for the effects due to the patch potentials in the complete data analysis model to yield determinations of the two GR effects. (paper)

  20. Probing the Terrain

    DEFF Research Database (Denmark)

    Johannessen, Runa

    2016-01-01

    Whether manifest in built structures or invisible infrastructures, architectures of control in the occupied Palestinian West Bank is structurally defined by endemic uncertainty. Shifting lines and frontiers are recorded on the terrain, creating elastic zones of uncertainty necessitating navigatio...... to the territory through its lines and laws, and how the very structure of the occupation has changed over the years, I seek to make visible the ways in which architectures of uncertainty compensate for the fleeting terrain that HH is probing.......Whether manifest in built structures or invisible infrastructures, architectures of control in the occupied Palestinian West Bank is structurally defined by endemic uncertainty. Shifting lines and frontiers are recorded on the terrain, creating elastic zones of uncertainty necessitating...

  1. Heat transfer probe

    Science.gov (United States)

    Frank, Jeffrey I.; Rosengart, Axel J.; Kasza, Ken; Yu, Wenhua; Chien, Tai-Hsin; Franklin, Jeff

    2006-10-10

    Apparatuses, systems, methods, and computer code for, among other things, monitoring the health of samples such as the brain while providing local cooling or heating. A representative device is a heat transfer probe, which includes an inner channel, a tip, a concentric outer channel, a first temperature sensor, and a second temperature sensor. The inner channel is configured to transport working fluid from an inner inlet to an inner outlet. The tip is configured to receive at least a portion of the working fluid from the inner outlet. The concentric outer channel is configured to transport the working fluid from the inner outlet to an outer outlet. The first temperature sensor is coupled to the tip, and the second temperature sensor spaced apart from the first temperature sensor.

  2. Solar Probe Plus

    Science.gov (United States)

    Szabo, Adam

    2011-01-01

    The NASA Solar Probe Plus mission is planned to be launched in 2018 to study the upper solar corona with both.in-situ and remote sensing instrumentation. The mission will utilize 6 Venus gravity assist maneuver to gradually lower its perihelion to 9.5 Rs below the expected Alfven pOint to study the sub-alfvenic solar wind that is still at least partially co-rotates with the Sun. The detailed science objectives of this mission will be discussed. SPP will have a strong synergy with The ESA/NASA Solar orbiter mission to be launched a year ahead. Both missions will focus on the inner heliosphere and will have complimentary instrumentations. Strategies to exploit this synergy will be also presented.

  3. Cosmological Probes for Supersymmetry

    Directory of Open Access Journals (Sweden)

    Maxim Khlopov

    2015-05-01

    Full Text Available The multi-parameter character of supersymmetric dark-matter models implies the combination of their experimental studies with astrophysical and cosmological probes. The physics of the early Universe provides nontrivial effects of non-equilibrium particles and primordial cosmological structures. Primordial black holes (PBHs are a profound signature of such structures that may arise as a cosmological consequence of supersymmetric (SUSY models. SUSY-based mechanisms of baryosynthesis can lead to the possibility of antimatter domains in a baryon asymmetric Universe. In the context of cosmoparticle physics, which studies the fundamental relationship of the micro- and macro-worlds, the development of SUSY illustrates the main principles of this approach, as the physical basis of the modern cosmology provides cross-disciplinary tests in physical and astronomical studies.

  4. Trapping and Probing Antihydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Wurtele, Jonathan [UC Berkeley and LBNL

    2013-03-27

    Precision spectroscopy of antihydrogen is a promising path to sensitive tests of CPT symmetry. The most direct route to achieve this goal is to create and probe antihydrogen in a magnetic minimum trap. Antihydrogen has been synthesized and trapped for 1000s at CERN by the ALPHA Collaboration. Some of the challenges associated with achieving these milestones will be discussed, including mixing cryogenic positron and antiproton plasmas to synthesize antihydrogen with kinetic energy less than the trap potential of .5K. Recent experiments in which hyperfine transitions were resonantly induced with microwaves will be presented. The opportunity for gravitational measurements in traps based on detailed studies of antihydrogen dynamics will be described. The talk will conclude with a discussion future antihydrogen research that will use a new experimental apparatus, ALPHA-I.

  5. Traversing incore probe device

    International Nuclear Information System (INIS)

    Yoshioka, Michiko.

    1985-01-01

    Purpose: To measure the neutron flux distribution in the reactor core always at a high accuracy. Constitution: A nuclear fission ionizing chamber type detector is disposed at the end of a cable for sending a detection signal of a traversing incore probe device and, further, a gamma-ray ionizing chamber type detector is connected in adjacent therewith and a selection circuit for selecting both of the detection signals and inputting them to a display device is disposed. Then, compensation for the neutron monitors is conducted by the gamma-ray ionizing chamber type detector during normal operation in which control rods are not driven and the positioning is carried out by the nuclear fission ionizing chamber type detector. Furthermore, both of the compensation for the neutron detector and the positioning are carried out by the nuclear fission ionizing chamber type detector upon starting where the control rods are driven. (Sekiya, K.)

  6. Hyperfine interactions in MnAs studied by perturbed angular correlations of $\\gamma$-rays using the probe $^{77}$Br $\\rightarrow ^{77}$Se and first principles calculations for MnAs and other Mn pnictides

    CERN Document Server

    Gonçalves, J N; Correia, J G; Lopes, A M L

    2011-01-01

    The MnAs compound shows a first-order transition at T$_{c}$≈ 42$^{\\circ}$C, and a second-order transition at T$_{t}$ ≈120$^{\\circ}$C. The first-order transition, with structural (hexagonal-orthorhombic), magnetic (FM-PM) and electrical conductivity changes, is associated to magnetocaloric, magnetoelastic, and magnetoresistance effects. We report a study in a large temperature range from −196$^{\\circ}$C up to 140$^{\\circ}$C, using the $\\gamma\\!-\\!\\gamma$ perturbed angular correlations method with the radioactive probe $^{77}$Br→$^{77}$Se, produced at the ISOLDE-CERN facility. The electric field gradients and magnetic hyperfine fields are determined across the first- and second-order phase transitions encompassing the pure and mixed phase regimes in cooling and heating cycles. The temperature irreversibility of the 1st order phase transition is seen locally, at the nanoscopic scale sensitivity of the hyperfine field, by its hysteresis, detailing and complementing information obtained with macroscopic me...

  7. Nanobits: customizable scanning probe tips

    DEFF Research Database (Denmark)

    Kumar, Rajendra; Shaik, Hassan Uddin; Sardan Sukas, Özlem

    2009-01-01

    We present here a proof-of-principle study of scanning probe tips defined by planar nanolithography and integrated with AFM probes using nanomanipulation. The so-called 'nanobits' are 2-4 mu m long and 120-150 nm thin flakes of Si3N4 or SiO2, fabricated by electron beam lithography and standard s...

  8. Gene probes: principles and protocols

    National Research Council Canada - National Science Library

    Aquino de Muro, Marilena; Rapley, Ralph

    2002-01-01

    ... of labeled DNA has allowed genes to be mapped to single chromosomes and in many cases to a single chromosome band, promoting significant advance in human genome mapping. Gene Probes: Principles and Protocols presents the principles for gene probe design, labeling, detection, target format, and hybridization conditions together with detailed protocols, accom...

  9. Non-inductive current probe

    DEFF Research Database (Denmark)

    Bak, Christen Kjeldahl

    1977-01-01

    The current probe described is a low-cost, shunt resistor for monitoring current pulses in e.g., pulsed lasers. Rise time is......The current probe described is a low-cost, shunt resistor for monitoring current pulses in e.g., pulsed lasers. Rise time is...

  10. A conformation-selective IR-UV study of the dipeptides Ac-Phe-Ser-NH2 and Ac-Phe-Cys-NH2: probing the SH···O and OH···O hydrogen bond interactions.

    Science.gov (United States)

    Yan, Bin; Jaeqx, Sander; van der Zande, Wim J; Rijs, Anouk M

    2014-06-14

    The conformational preferences of peptides are mainly controlled by the stabilizing effect of intramolecular interactions. In peptides with polar side chains, not only the backbone but also the side chain interactions determine the resulting conformations. In this paper, the conformational preferences of the capped dipeptides Ac-Phe-Ser-NH2 (FS) and Ac-Phe-Cys-NH2 (FC) are resolved under laser-desorbed jet cooling conditions using IR-UV ion dip spectroscopy and density functional theory (DFT) quantum chemistry calculations. As serine (Ser) and cysteine (Cys) only differ in an OH (Ser) or SH (Cys) moiety; this subtle alteration allows us to study the effect of the difference in hydrogen bonding for an OH and SH group in detail, and its effect on the secondary structure. IR absorption spectra are recorded in the NH stretching region (3200-3600 cm(-1)). In combination with quantum chemical calculations the spectra provide a direct view of intramolecular interactions. Here, we show that both FS as FC share a singly γ-folded backbone conformation as the most stable conformer. The hydrogen bond strength of OH···O (FS) is stronger than that of SH···O (FC), resulting in a more compact gamma turn structure. A second conformer is found for FC, showing a β turn interaction.

  11. Water cooled static pressure probe

    Science.gov (United States)

    Lagen, Nicholas T. (Inventor); Eves, John W. (Inventor); Reece, Garland D. (Inventor); Geissinger, Steve L. (Inventor)

    1991-01-01

    An improved static pressure probe containing a water cooling mechanism is disclosed. This probe has a hollow interior containing a central coolant tube and multiple individual pressure measurement tubes connected to holes placed on the exterior. Coolant from the central tube symmetrically immerses the interior of the probe, allowing it to sustain high temperature (in the region of 2500 F) supersonic jet flow indefinitely, while still recording accurate pressure data. The coolant exits the probe body by way of a reservoir attached to the aft of the probe. The pressure measurement tubes are joined to a single, larger manifold in the reservoir. This manifold is attached to a pressure transducer that records the average static pressure.

  12. Probe beam deflection technique as acoustic emission directionality sensor with photoacoustic emission source.

    Science.gov (United States)

    Barnes, Ronald A; Maswadi, Saher; Glickman, Randolph; Shadaram, Mehdi

    2014-01-20

    The goal of this paper is to demonstrate the unique capability of measuring the vector or angular information of propagating acoustic waves using an optical sensor. Acoustic waves were generated using photoacoustic interaction and detected by the probe beam deflection technique. Experiments and simulations were performed to study the interaction of acoustic emissions with an optical sensor in a coupling medium. The simulated results predict the probe beam and wavefront interaction and produced simulated signals that are verified by experiment.

  13. Probing the Big Bang with LEP

    Energy Technology Data Exchange (ETDEWEB)

    Schramm, D.N. (Chicago Univ., IL (USA) Fermi National Accelerator Lab., Batavia, IL (USA))

    1990-06-01

    It is shown that LEP probes the Big Bang in two significant ways: (1) nucleosynthesis and (2) dark matter constraints. In the first case, LEP verifies the cosmological standard model prediction on the number of neutrino types, thus strengthening the conclusion that the cosmological baryon density is {approximately}6% of the critical value. In the second case, LEP shows that the remaining non-baryonic cosmological matter must be somewhat more massive and/or more weakly interacting that the favorite non-baryonic dark matter candidates of a few years ago. 59 refs., 4 figs., 2 tabs.

  14. Probing the Big Bang with LEP

    International Nuclear Information System (INIS)

    Schramm, D.N.

    1990-06-01

    It is shown that LEP probes the Big Bang in two significant ways: (1) nucleosynthesis and (2) dark matter constraints. In the first case, LEP verifies the cosmological standard model prediction on the number of neutrino types, thus strengthening the conclusion that the cosmological baryon density is ∼6% of the critical value. In the second case, LEP shows that the remaining non-baryonic cosmological matter must be somewhat more massive and/or more weakly interacting that the favorite non-baryonic dark matter candidates of a few years ago. 59 refs., 4 figs., 2 tabs

  15. Probing the Big Bang with LEP

    Science.gov (United States)

    Schramm, David N.

    1990-01-01

    It is shown that LEP probes the Big Bang in two significant ways: (1) nucleosynthesis, and (2) dark matter constraints. In the first case, LEP verifies the cosmological standard model prediction on the number of neutrino types, thus strengthening the conclusion that the cosmological baryon density is approximately 6 percent of the critical value. In the second case, LEP shows that the remaining non-baryonic cosmological matter must be somewhat more massive and/or more weakly interacting than the favorite non-baryonic dark matter candidates of a few years ago.

  16. Gravity Probe B Encapsulated

    Science.gov (United States)

    2004-01-01

    In this photo, the Gravity Probe B (GP-B) space vehicle is being encapsulated atop the Delta II launch vehicle. The GP-B is the relativity experiment developed at Stanford University to test two extraordinary predictions of Albert Einstein's general theory of relativity. The experiment will measure, very precisely, the expected tiny changes in the direction of the spin axes of four gyroscopes contained in an Earth-orbiting satellite at a 400-mile altitude. So free are the gyroscopes from disturbance that they will provide an almost perfect space-time reference system. They will measure how space and time are very slightly warped by the presence of the Earth, and, more profoundly, how the Earth's rotation very slightly drags space-time around with it. These effects, though small for the Earth, have far-reaching implications for the nature of matter and the structure of the Universe. GP-B is among the most thoroughly researched programs ever undertaken by NASA. This is the story of a scientific quest in which physicists and engineers have collaborated closely over many years. Inspired by their quest, they have invented a whole range of technologies that are already enlivening other branches of science and engineering. Launched April 20, 2004 , the GP-B program was managed for NASA by the Marshall Space Flight Center. Development of the GP-B is the responsibility of Stanford University along with major subcontractor Lockheed Martin Corporation. (Image credit to Russ Underwood, Lockheed Martin Corporation).

  17. Steerable Doppler transducer probes

    International Nuclear Information System (INIS)

    Fidel, H.F.; Greenwood, D.L.

    1986-01-01

    An ultrasonic diagnostic probe is described which is capable of performing ultrasonic imaging and Doppler measurement consisting of: a hollow case having an acoustic window which passes ultrasonic energy and including chamber means for containing fluid located within the hollow case and adjacent to a portion of the acoustic window; imaging transducer means, located in the hollow case and outside the fluid chamber means, and oriented to direct ultrasonic energy through the acoustic window toward an area which is to be imaged; Doppler transducer means, located in the hollow case within the fluid chamber means, and movably oriented to direct Doppler signals through the acoustic window toward the imaged area; means located within the fluid chamber means and externally controlled for controllably moving the Doppler transducer means to select one of a plurality of axes in the imaged area along which the Doppler signals are to be directed; and means, located external to the fluid chamber means and responsive to the means for moving, for providing an indication signal for identifying the selected axis

  18. Synthesis, spectroscopic characterization and in vitro cytotoxicities of new organometallic palladium complexes with biologically active β-diketones; Biological evaluation probing of the interaction mechanism with DNA/Protein and molecular docking

    Science.gov (United States)

    Karami, Kazem; Rafiee, Mina; Lighvan, Zohreh Mehri; Zakariazadeh, Mostafa; Faal, Ali Yeganeh; Esmaeili, Seyed-Alireza; Momtazi-Borojeni, Amir Abbas

    2018-02-01

    [Pd{(C,N)sbnd C6H4CH (CH3)NH}(CUR)] (3) and [Pd2{(C,N)sbnd C6H4CH(CH3)NH2}2(μ-N3CS2)] (4) [cur = 1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dion] novel organometallic complexes with biologically active ligands have been prepared and characterized via elemental analysis, multinuclear spectroscopic techniques (1H, and 13C NMR and IR) and their biological activities, including antitumoral activity and DNA-protein interactions have been investigated. Fluorescence spectroscopy used to study the interaction of the complexes with BSA have shown the affinity of the complexes for these proteins with relatively high binding constant values and the changed secondary structure of BSA in the presence of the complexes. In the meantime, spectroscopy and competitive titration have been applied to investigate the interaction of complexes with Warfarin and Ibuprofen site markers for sites I and II, respectively, with BSA. The results have suggested that the locations of complexes 3 and 4 are sites II and I, respectively. UV-Vis spectroscopy, emission titration and helix melting methods have been used to study the interaction of these complexes with CT-DNA, indicating that complexes are bound to CT-DNA by intercalation binding mode. In addition, good cytotoxic activity against MCF-7 (human breast cancer) and JURKAT (human leukemia) cell line has been shown by both complexes whereas low cytotoxicity was exerted on normal peripheral blood mononuclear cells.

  19. ProbeZT: Simulation of transport coefficients of molecular electronic junctions under environmental effects using Büttiker's probes

    Science.gov (United States)

    Korol, Roman; Kilgour, Michael; Segal, Dvira

    2018-03-01

    We present our in-house quantum transport package, ProbeZT. This program provides linear response coefficients: electrical and electronic thermal conductances, as well as the thermopower of molecular junctions in which electrons interact with the surrounding thermal environment. Calculations are performed based on the Büttiker probe method, which introduces decoherence, energy exchange and dissipation effects phenomenologically using virtual electrode terminals called probes. The program can realize different types of probes, each introducing various environmental effects, including elastic and inelastic scattering of electrons. The molecular system is described by an arbitrary tight-binding Hamiltonian, allowing the study of different geometries beyond simple one-dimensional wires. Applications of the program to study the thermoelectric performance of molecular junctions are illustrated. The program also has a built-in functionality to simulate electron transport in double-stranded DNA molecules based on a tight-binding (ladder) description of the junction.

  20. Weak interactions with nuclei

    International Nuclear Information System (INIS)

    Walecka, J.D.

    1983-01-01

    Nuclei provide systems where the strong, electomagnetic, and weak interactions are all present. The current picture of the strong interactions is based on quarks and quantum chromodynamics (QCD). The symmetry structure of this theory is SU(3)/sub C/ x SU(2)/sub W/ x U(1)/sub W/. The electroweak interactions in nuclei can be used to probe this structure. Semileptonic weak interactions are considered. The processes under consideration include beta decay, neutrino scattering and weak neutral-current interactions. The starting point in the analysis is the effective Lagrangian of the Standard Model

  1. Theoretical Probing of Weak Anion-Cation Interactions in Certain Pyridinium-Based Ionic Liquid Ion Pairs and the Application of Molecular Electrostatic Potential in Their Ionic Crystal Density Determination: A Comparative Study Using Density Functional Approach.

    Science.gov (United States)

    Joseph, Aswathy; Thomas, Vibin Ipe; Żyła, Gaweł; Padmanabhan, A S; Mathew, Suresh

    2018-01-11

    A comprehensive study on the structure, nature of interaction, and properties of six ionic pairs of 1-butylpyridinium and 1-butyl-4-methylpyridinium cations in combination with tetrafluoroborate (BF 4 - ), chloride (Cl - ), and bromide (Br - ) anions have been carried out using density functional theory (DFT). The anion-cation interaction energy (ΔE int ), thermochemistry values, theoretical band gap, molecular orbital energy order, DFT-based chemical activity descriptors [chemical potential (μ), chemical hardness (η), and electrophilicity index (ω)], and distribution of density of states (DOS) of these ion pairs were investigated. The ascendancy of the -CH 3 substituent at the fourth position of the 1-butylpyridinium cation ring on the values of ΔE int , theoretical band gap and chemical activity descriptors was evaluated. The ΔE int values were negative for all six ion pairs and were highest for Cl - containing ion pairs. The theoretical band gap value after -CH 3 substitution increased from 3.78 to 3.96 eV (for Cl - ) and from 2.74 to 2.88 eV (for Br - ) and decreased from 4.9 to 4.89 eV (for BF 4 - ). Ion pairs of BF 4 - were more susceptible to charge transfer processes as inferred from their significantly high η values and comparatively small difference in ω value after -CH 3 substitution. The change in η and μ values due to the -CH 3 substituent is negligibly small in all cases except for the ion pairs of Cl - . Critical-point (CP) analyses were carried out to investigate the AIM topological parameters at the interionic bond critical points (BCPs). The RDG isosurface analysis indicated that the anion-cation interaction was dominated by strong H cat ···X ani and C cat ···X ani interactions in ion pairs of Cl - and Br - whereas a weak van der Waal's effect dominated in ion pairs of BF 4 - . The molecular electrostatic potential (MESP)-based parameter ΔΔV min measuring the anion-cation interaction strength showed a good linear correlation with

  2. Nanofabrication of magnetic scanned-probe microscope sensors

    International Nuclear Information System (INIS)

    Chong, B.K.

    2001-10-01

    This thesis presents the development of novel magnetic sensor combined with Atomic Force Microscope probe (AFM) using conventional semiconductor processing techniques and Electron Beam Lithography (EBL). The fabrication of these magnetic sensors was performed on a common micromachined silicon substrate using a generic batch fabrication technique. Sub-micron Hall bar for Scanning Hall probe Microscopy (SHPM) and electromagnetic force coil magnet for Scanning Electromagnetic Force Microscopy (eMFM) were designed and constructed at the apex of Silicon attractive mode cantilever probes. The process demonstrates good control over sensor parameters. Results indicated controllability of Hall bar junction sizes (spatial resolution) to below 100nm and Coil diameter sizes to below 500nm with minimum sizes down to 50nm and 270nm respectively. The process has shown its flexibility to accommodate different material systems. The same technology was used to fabricate multiple devices such as double Hall bars on a tip as well as a small electro-magnet coil probe co-defined with the Hall probe to form a magnetic imaging / modification probe. A conventional Non-Contact mode AFM employing heterodyne interferometry and in-house built electronics was modified for SHPM and eMFM. These probes had been scanned over a commercial computer hard disk. These microscopes showed the capability of resolving magnetic bits and topographic information independently and simultaneously. All scanning experiments were carried out under ambient conditions. The experiments required no extra preparation to be done to the specimen before imaging and measurements were carried out under ambient conditions. These probes offer the prospect of direct magnetic field measurement, non- invasiveness, very close proximity, possible local manipulation, better control over the tip- specimen interaction distance and topographic imaging. It is hoped that these magnetic microscope probes will be of great interest and

  3. STM-SQUID probe microscope

    International Nuclear Information System (INIS)

    Hayashi, Tadayuki; Tachiki, Minoru; Itozaki, Hideo

    2007-01-01

    We have developed a STM-SQUID probe microscope. A high T C SQUID probe microscope was combined with a scanning tunneling microscope for investigation of samples at room temperature in air. A high permeability probe needle was used as a magnetic flux guide to improve the spatial resolution. The probe with tip radius of less than 100 nm was prepared by microelectropolishing. The probe was also used as a scanning tunneling microscope tip. Topography of the sample surface could be measured by the scanning tunneling microscope with high spatial resolution prior to observation by SQUID microscopy. The SQUID probe microscope image could be observed while keeping the distance from the sample surface to the probe tip constant. We observed a topographic image and a magnetic image of Ni fine pattern and also a magnetically recorded hard disk. Furthermore we have investigated a sample vibration method of the static magnetic field emanating from a sample with the aim of achieving a higher signal-to-noise (S/N) ratio

  4. The AMEMIYA probe. Theoretical background

    International Nuclear Information System (INIS)

    Belitz, Hans Joahim; Althausen, Bernhard; Uehara, Kazuya; Amemiya, Hiroshi

    2010-01-01

    The present probe was developed in order to measure the temperature T i of positive ions in the scrape-off layer (SOL) of tokamak where T i is usually larger than the electron temperature Ti so that the presheath in front of the probe need not be considered and the ions reach the probe with the thermal velocity. The axis of the cylindrical probe is placed parallel to the magnetic field. The important parameter are L/a, the ratio of the length to the radius of the cylindrical probe and κ, the ratio of the probe radius to (π/4) 1/2 , where is the mean ion Larmor radius. The ion current densities to the side and the end surfaces are expressed by the double integral, which can give an analytical formula with respect to the value of κ. If two electrodes with different lengths are placed parallel to the magnetic field, the difference of current densities can be reduced to κ and hence to Ti. Some examples of the application of the probe to tokamaks, JFT-2M and Textor, are demonstrated. (author)

  5. Aligned ion implementation using scanning probes

    Energy Technology Data Exchange (ETDEWEB)

    Persaud, A

    2006-12-12

    A new technique for precision ion implantation has been developed. A scanning probe has been equipped with a small aperture and incorporated into an ion beamline, so that ions can be implanted through the aperture into a sample. By using a scanning probe the target can be imaged in a non-destructive way prior to implantation and the probe together with the aperture can be placed at the desired location with nanometer precision. In this work first results of a scanning probe integrated into an ion beamline are presented. A placement resolution of about 120 nm is reported. The final placement accuracy is determined by the size of the aperture hole and by the straggle of the implanted ion inside the target material. The limits of this technology are expected to be set by the latter, which is of the order of 10 nm for low energy ions. This research has been carried out in the context of a larger program concerned with the development of quantum computer test structures. For that the placement accuracy needs to be increased and a detector for single ion detection has to be integrated into the setup. Both issues are discussed in this thesis. To achieve single ion detection highly charged ions are used for the implantation, as in addition to their kinetic energy they also deposit their potential energy in the target material, therefore making detection easier. A special ion source for producing these highly charged ions was used and their creation and interactions with solids of are discussed in detail. (orig.)

  6. Aligned ion implantation using scanning probes

    International Nuclear Information System (INIS)

    Persaud, A.

    2006-01-01

    A new technique for precision ion implantation has been developed. A scanning probe has been equipped with a small aperture and incorporated into an ion beamline, so that ions can be implanted through the aperture into a sample. By using a scanning probe the target can be imaged in a non-destructive way prior to implantation and the probe together with the aperture can be placed at the desired location with nanometer precision. In this work first results of a scanning probe integrated into an ion beamline are presented. A placement resolution of about 120 nm is reported. The final placement accuracy is determined by the size of the aperture hole and by the straggle of the implanted ion inside the target material. The limits of this technology are expected to be set by the latter, which is of the order of 10 nm for low energy ions. This research has been carried out in the context of a larger program concerned with the development of quantum computer test structures. For that the placement accuracy needs to be increased and a detector for single ion detection has to be integrated into the setup. Both issues are discussed in this thesis. To achieve single ion detection highly charged ions are used for the implantation, as in addition to their kinetic energy they also deposit their potential energy in the target material, therefore making detection easier. A special ion source for producing these highly charged ions was used and their creation and interactions with solids of are discussed in detail. (orig.)

  7. DeepProbe: Information Directed Sequence Understanding and Chatbot Design via Recurrent Neural Networks

    OpenAIRE

    Yin, Zi; Chang, Keng-hao; Zhang, Ruofei

    2017-01-01

    Information extraction and user intention identification are central topics in modern query understanding and recommendation systems. In this paper, we propose DeepProbe, a generic information-directed interaction framework which is built around an attention-based sequence to sequence (seq2seq) recurrent neural network. DeepProbe can rephrase, evaluate, and even actively ask questions, leveraging the generative ability and likelihood estimation made possible by seq2seq models. DeepProbe makes...

  8. Integrated microfluidic probe station.

    Science.gov (United States)

    Perrault, C M; Qasaimeh, M A; Brastaviceanu, T; Anderson, K; Kabakibo, Y; Juncker, D

    2010-11-01

    The microfluidic probe (MFP) consists of a flat, blunt tip with two apertures for the injection and reaspiration of a microjet into a solution--thus hydrodynamically confining the microjet--and is operated atop an inverted microscope that enables live imaging. By scanning across a surface, the microjet can be used for surface processing with the capability of both depositing and removing material; as it operates under immersed conditions, sensitive biological materials and living cells can be processed. During scanning, the MFP is kept immobile and centered over the objective of the inverted microscope, a few micrometers above a substrate that is displaced by moving the microscope stage and that is flushed continuously with the microjet. For consistent and reproducible surface processing, the gap between the MFP and the substrate, the MFP's alignment, the scanning speed, the injection and aspiration flow rates, and the image capture need all to be controlled and synchronized. Here, we present an automated MFP station that integrates all of these functionalities and automates the key operational parameters. A custom software program is used to control an independent motorized Z stage for adjusting the gap, a motorized microscope stage for scanning the substrate, up to 16 syringe pumps for injecting and aspirating fluids, and an inverted fluorescence microscope equipped with a charge-coupled device camera. The parallelism between the MFP and the substrate is adjusted using manual goniometer at the beginning of the experiment. The alignment of the injection and aspiration apertures along the scanning axis is performed using a newly designed MFP screw holder. We illustrate the integrated MFP station by the programmed, automated patterning of fluorescently labeled biotin on a streptavidin-coated surface.

  9. Gravity Probe B Assembled

    Science.gov (United States)

    2000-01-01

    In this photo, the Gravity Probe B (GP-B) space vehicle is being assembled at the Sunnyvale, California location of the Lockheed Martin Corporation. The GP-B is the relativity experiment developed at Stanford University to test two extraordinary predictions of Albert Einstein's general theory of relativity. The experiment will measure, very precisely, the expected tiny changes in the direction of the spin axes of four gyroscopes contained in an Earth-orbiting satellite at a 400-mile altitude. So free are the gyroscopes from disturbance that they will provide an almost perfect space-time reference system. They will measure how space and time are very slightly warped by the presence of the Earth, and, more profoundly, how the Earth's rotation very slightly drags space-time around with it. These effects, though small for the Earth, have far-reaching implications for the nature of matter and the structure of the Universe. GP-B is among the most thoroughly researched programs ever undertaken by NASA. This is the story of a scientific quest in which physicists and engineers have collaborated closely over many years. Inspired by their quest, they have invented a whole range of technologies that are already enlivening other branches of science and engineering. Launched April 20, 2004 , the GP-B program was managed for NASA by the Marshall Space Flight Center. Development of the GP-B is the responsibility of Stanford University along with major subcontractor Lockheed Martin Corporation. (Image credit to Russ Underwood, Lockheed Martin Corporation).

  10. Short recovery time NMR probe

    International Nuclear Information System (INIS)

    Ramia, M.E.; Martin, C.A.; Jeandrevin, S.

    2011-01-01

    A NMR probe for low frequency and short recovery time is presented in this work. The probe contains the tuning circuit, diode expanders and quarter wavelength networks to protect the receiver from both the amplifier noise and the coil ringing following the transmitter power pulse. It also possesses a coil damper which is activated by of non active components. The probe performance shows a recovery time of about of 15μs a sensitive Q factor reduction and an increase of the signal to noise ratio of about 68% during the reception at a work frequency of 2 MHz. (author)

  11. Probing the interaction of human serum albumin with vitamin B2 (riboflavin) and L-Arginine (L-Arg) using multi-spectroscopic, molecular modeling and zeta potential techniques

    Energy Technology Data Exchange (ETDEWEB)

    Memarpoor-Yazdi, Mina [Department of Biology, Faculty of Sciences, Mashhad Branch, Islamic Azad University, Mashhad (Iran, Islamic Republic of); Mahaki, Hanie, E-mail: hanieh.mahaki@gmail.com [Department of Biology, Faculty of Sciences, Mashhad Branch, Islamic Azad University, Mashhad (Iran, Islamic Republic of)

    2013-04-15

    This study was designed to examine the interaction of Riboflavin (RB) and L-Arginine (L-Arg) with human serum albumin (HSA) using different spectroscopic, zeta potential and molecular modeling techniques under imitated physiological conditions. The resonance light scattering (RLS) method determined the critical aggregation concentration of RB on HSA in the presence and absence of L-Arg which confirmed the zeta potential results. The binding constants (K{sub a}) of HSA–RB were 2.5×10{sup 4} and 9.7×10{sup 3} M{sup −1}, respectively in binary and ternary system at the excitation wavelength of 280 nm, also were 7.5×10{sup 3} and 7.3×10{sup 3}, respectively in binary and ternary system at the excitation wavelength of 295 nm. Fluorescence spectroscopy demonstrated that in the presence of L-Arg, the binding constant of HSA–RB was increased. Static quenching was confirmed to results in the fluorescence quenching and FRET. The binding distances between HSA and RB in two- and three-component systems were estimated by the Forster theory which revealed that nonradiative energy transfer from HSA to RB occurred with a high probability. The effect of RB on the conformation of HSA was analyzed using synchronous fluorescence spectroscopy and circular dichroism (CD) in both systems. Docking studies demonstrated a reduction in the binding affinity between RB and HSA in the presence of L-Arg. -- Highlights: ► We studied the interaction of riboflavin with HSA in presence and absence of L-Arg. ► Molecular modeling and zeta-potential used to describe competitive interaction. ► We compared the binding mechanism of riboflavin (RB) to HSA in both systems. ► We determined critical aggregation concentration of RB on HSA in both systems. ► The binding site of RB on HSA in both systems has been determined.

  12. Probing the interaction of human serum albumin with vitamin B2 (riboflavin) and L-Arginine (L-Arg) using multi-spectroscopic, molecular modeling and zeta potential techniques

    International Nuclear Information System (INIS)

    Memarpoor-Yazdi, Mina; Mahaki, Hanie

    2013-01-01

    This study was designed to examine the interaction of Riboflavin (RB) and L-Arginine (L-Arg) with human serum albumin (HSA) using different spectroscopic, zeta potential and molecular modeling techniques under imitated physiological conditions. The resonance light scattering (RLS) method determined the critical aggregation concentration of RB on HSA in the presence and absence of L-Arg which confirmed the zeta potential results. The binding constants (K a ) of HSA–RB were 2.5×10 4 and 9.7×10 3 M −1 , respectively in binary and ternary system at the excitation wavelength of 280 nm, also were 7.5×10 3 and 7.3×10 3 , respectively in binary and ternary system at the excitation wavelength of 295 nm. Fluorescence spectroscopy demonstrated that in the presence of L-Arg, the binding constant of HSA–RB was increased. Static quenching was confirmed to results in the fluorescence quenching and FRET. The binding distances between HSA and RB in two- and three-component systems were estimated by the Forster theory which revealed that nonradiative energy transfer from HSA to RB occurred with a high probability. The effect of RB on the conformation of HSA was analyzed using synchronous fluorescence spectroscopy and circular dichroism (CD) in both systems. Docking studies demonstrated a reduction in the binding affinity between RB and HSA in the presence of L-Arg. -- Highlights: ► We studied the interaction of riboflavin with HSA in presence and absence of L-Arg. ► Molecular modeling and zeta-potential used to describe competitive interaction. ► We compared the binding mechanism of riboflavin (RB) to HSA in both systems. ► We determined critical aggregation concentration of RB on HSA in both systems. ► The binding site of RB on HSA in both systems has been determined

  13. High Speed Pump-Probe Apparatus for Observation of Transitional Effects in Ultrafast Laser Micromachining Processes

    Directory of Open Access Journals (Sweden)

    Ilya Alexeev

    2015-12-01

    Full Text Available A pump-probe experimental approach has been shown to be a very efficient tool for the observation and analysis of various laser matter interaction effects. In those setups, synchronized laser pulses are used to create an event (pump and to simultaneously observe it (probe. In general, the physical effects that can be investigated with such an apparatus are restricted by the temporal resolution of the probe pulse and the observation window. The latter can be greatly extended by adjusting the pump-probe time delay under the assumption that the interaction process remains fairly reproducible. Unfortunately, this assumption becomes invalid in the case of high-repetition-rate ultrafast laser material processing, where the irradiation history strongly affects the ongoing interaction process. In this contribution, the authors present an extension of the pump-probe setup that allows to investigate transitional and dynamic effects present during ultrafast laser machining performed at high pulse repetition frequencies.

  14. Single-molecule pull-down (SiMPull) for new-age biochemistry: methodology and biochemical applications of single-molecule pull-down (SiMPull) for probing biomolecular interactions in crude cell extracts.

    Science.gov (United States)

    Aggarwal, Vasudha; Ha, Taekjip

    2014-11-01

    Macromolecular interactions play a central role in many biological processes. Protein-protein interactions have mostly been studied by co-immunoprecipitation, which cannot provide quantitative information on all possible molecular connections present in the complex. We will review a new approach that allows cellular proteins and biomolecular complexes to be studied in real-time at the single-molecule level. This technique is called single-molecule pull-down (SiMPull), because it integrates principles of conventional immunoprecipitation with the powerful single-molecule fluorescence microscopy. SiMPull is used to count how many of each protein is present in the physiological complexes found in cytosol and membranes. Concurrently, it serves as a single-molecule biochemical tool to perform functional studies on the pulled-down proteins. In this review, we will focus on the detailed methodology of SiMPull, its salient features and a wide range of biological applications in comparison with other biosensing tools. © 2014 WILEY Periodicals, Inc.

  15. Aspects of tactile probing on a micro scale

    NARCIS (Netherlands)

    Bos, E.J.C.; Schellekens, P.H.J.; Dietzel, A.H.

    2009-01-01

    Measurement instruments are sensitive to more than one physical quantity. When measuring work piece topography, the measurement result will always be influenced by the environment and (local) variations in the work piece itself. The aspects that influence the interaction between probe tip and work

  16. Lepton probes in nuclear physics

    Energy Technology Data Exchange (ETDEWEB)

    Arvieux, J. [Laboratoire National Saturne, Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France)

    1994-12-31

    Facilities are overviewed which use the lepton probe to learn about nuclear physics. The lepton accelerating methods out some existing facilities are considered. The ELFE project is discussed in detail. (K.A.). 43 refs., 15 figs., 4 tabs.

  17. Probing of flowing electron plasmas

    International Nuclear Information System (INIS)

    Himura, H.; Nakashima, C.; Saito, H.; Yoshida, Z.

    2001-01-01

    Probing of streaming electron plasmas with finite temperature is studied. For the first time, a current-voltage characteristic of an electric probe is measured in electron plasmas. Due to the fast flow of the electron plasmas, the characteristic curve spreads out significantly and exhibits a long tail. This feature can be explained calculating the currents collected to the probe. In flowing electron plasmas, the distribution function observed in the laboratory frame is non-Maxwellian even if the plasmas come to a state of thermal equilibrium. Another significant feature of the characteristic is that it determines a floating potential where the current equals zero, despite there being very few ions in the electron plasma. A high impedance probe, which is popularly used to determine the space potential of electron plasmas, outputs the potential. The method is available only for plasmas with density much smaller than the Brillouin limit

  18. Monitoring probe for groundwater flow

    Science.gov (United States)

    Looney, B.B.; Ballard, S.

    1994-08-23

    A monitoring probe for detecting groundwater migration is disclosed. The monitor features a cylinder made of a permeable membrane carrying an array of electrical conductivity sensors on its outer surface. The cylinder is filled with a fluid that has a conductivity different than the groundwater. The probe is placed in the ground at an area of interest to be monitored. The fluid, typically saltwater, diffuses through the permeable membrane into the groundwater. The flow of groundwater passing around the permeable membrane walls of the cylinder carries the conductive fluid in the same general direction and distorts the conductivity field measured by the sensors. The degree of distortion from top to bottom and around the probe is precisely related to the vertical and horizontal flow rates, respectively. The electrical conductivities measured by the sensors about the outer surface of the probe are analyzed to determine the rate and direction of the groundwater flow. 4 figs.

  19. Pneumatic probe with laser interferometer

    International Nuclear Information System (INIS)

    Wilkens, P.H.

    1978-01-01

    Improvements to upgrade the accuracy of Rotacon probes by a complete redesign of probe to include a Michelson interferometer to replace the existing long-range capacity transducer are described. This has resulted in a compact and interchangeable probe cartridge with a 3 μin. resolution and accuracy; the cartridge can be installed and replaced in the Rotacon gauge with the minimum of realignment, which should reduce our dependence on operator skill. In addition, the stylus contact force can be reduced to 750 mg for the contacting types, but an alternative feature, which we are still developing, will use a gas jet cushion in place of the stylus to provide a noncontacting version of the same basic probe cartridge. This device is very sensitive to external vibration effects because it is virtually frictionless

  20. Lepton probes in nuclear physics

    International Nuclear Information System (INIS)

    Arvieux, J.

    1994-01-01

    Facilities are overviewed which use the lepton probe to learn about nuclear physics. The lepton accelerating methods out some existing facilities are considered. The ELFE project is discussed in detail. (K.A.). 43 refs., 15 figs., 4 tabs

  1. DNA probe for lactobacillus delbrueckii

    Energy Technology Data Exchange (ETDEWEB)

    Delley, M.; Mollet, B.; Hottinger, H. (Nestle Research Centre, Lausanne (Switzerland))

    1990-06-01

    From a genomic DNA library of Lactobacillus delbrueckii subsp. bulgaricus, a clone was isolated which complements a leucine auxotrophy of an Escherichia coli strain (GE891). Subsequent analysis of the clone indicated that it could serve as a specific DNA probe. Dot-blot hybridizations with over 40 different Lactobacillus strains showed that this clone specifically recognized L. delbrueckii subsp. delbrueckii, bulgaricus, and lactis. The sensitivity of the method was tested by using an {alpha}-{sup 32}P-labeled probe.

  2. DNA probe for lactobacillus delbrueckii

    International Nuclear Information System (INIS)

    Delley, M.; Mollet, B.; Hottinger, H.

    1990-01-01

    From a genomic DNA library of Lactobacillus delbrueckii subsp. bulgaricus, a clone was isolated which complements a leucine auxotrophy of an Escherichia coli strain (GE891). Subsequent analysis of the clone indicated that it could serve as a specific DNA probe. Dot-blot hybridizations with over 40 different Lactobacillus strains showed that this clone specifically recognized L. delbrueckii subsp. delbrueckii, bulgaricus, and lactis. The sensitivity of the method was tested by using an α- 32 P-labeled probe

  3. QCD probes at LHC

    CERN Document Server

    Da Silveira, G. Gil

    2018-01-01

    The LHC experiments have reported new results with respect to the dynamics of the strong interactions in $pp$, $p$A, and AA collisions over the past years. In proton-proton collisions, the data analyses have focused in exploring the nature of underlying events and double parton scattering at high energies. For large systems, the heavy-ion collisions have provided new insights on physics aspects related to azimuthal correlations, jet quenching, and particle production, such as antiprotons. This Letter reports the recent results from the ATLAS, CMS, and LHCb Collaborations on these various topics and highlights its relevant findings for the high-energy community.

  4. Probe-controlled soliton frequency shift in the regime of optical event horizon

    DEFF Research Database (Denmark)

    Gu, Jie; Guo, Hairun; Wang, Shaofei

    2015-01-01

    In optical analogy of the event horizon, temporal pulse collision and mutual interactions are mainly between an intense solitary wave (soliton) and a dispersive probe wave. In such a regime, here we numerically investigate the probe-controlled soliton frequency shift as well as the soliton self...

  5. Double Layer of a Gold Electrode Probed by AFM Force Measurements

    NARCIS (Netherlands)

    Barten, D.; Kleijn, J.M.; Duval, J.F.L.; Leeuwen, van H.P.; Lyklema, J.; Cohen Stuart, M.A.

    2003-01-01

    Colloidal probe atomic force microscopy was used to determine the electric double layer interactions between a gold electrode and a spherical silica probe. The double layer properties of the gold/solution interface were varied through the pH and salt concentration of the electrolyte, as well as by

  6. Coating of AFM probes with aquatic humic and non-humic NOM to study their adhesion properties

    KAUST Repository

    Aubry, Cyril; Gutié rrez, Leonardo A.; Croue, Jean-Philippe

    2013-01-01

    -coated colloidal probes. AFM-generated force-distance curves were analyzed to elucidate the nature and mechanisms of these interacting forces. Electrostatics and steric interactions were important contributors to repulsive forces during approach, although

  7. Probe Selection for DNA Microarrays using OligoWiz

    DEFF Research Database (Denmark)

    Wernersson, Rasmus; Juncker, Agnieszka; Nielsen, Henrik Bjørn

    2007-01-01

    Nucleotide abundance measurements using DNA microarray technology are possible only if appropriate probes complementary to the target nucleotides can be identified. Here we present a protocol for selecting DNA probes for microarrays using the OligoWiz application. OligoWiz is a client-server appl......Nucleotide abundance measurements using DNA microarray technology are possible only if appropriate probes complementary to the target nucleotides can be identified. Here we present a protocol for selecting DNA probes for microarrays using the OligoWiz application. OligoWiz is a client......-server application that offers a detailed graphical interface and real-time user interaction on the client side, and massive computer power and a large collection of species databases (400, summer 2007) on the server side. Probes are selected according to five weighted scores: cross-hybridization, deltaT(m), folding...... computer skills and can be executed from any Internet-connected computer. The probe selection procedure for a standard microarray design targeting all yeast transcripts can be completed in 1 h....

  8. Electric probe data analysis for glow discharge diagnostics

    International Nuclear Information System (INIS)

    Cain, B.L.

    1987-01-01

    This report summarizes the development and application of digital computations for the analysis of data from an electric probe used for glow discharge diagnostics. The essential physics of the probe/discharge interaction is presented, along with formulations from modern electric probe theory. These results are then digitally implemented by a set of computer programs which both calculate discharge properties of electron temperature and density, and aid in the interpretation of these property estimates. The method of analysis, and the theories selected for implementation, are valid only for low pressure, collisionless sheath, and quiescent discharges where the single electric probe has a much smaller area than the discharge reference electrode. However, certain algorithms are included which, in some cases, can extend the analysis into intermediate pressure regimes. The digital programs' functional capabilities are demonstrated by the analysis of experimental probe data, collected using a laboratory glow discharge. Typical sources of error inherent in the electric probe method are discussed, along with an analysis of error induced by the computational methods of the programs. 27 refs., 49 figs., 20 tabs

  9. Seven novel probe systems for real-time PCR provide absolute single-base discrimination, higher signaling, and generic components.

    Science.gov (United States)

    Murray, James L; Hu, Peixu; Shafer, David A

    2014-11-01

    We have developed novel probe systems for real-time PCR that provide higher specificity, greater sensitivity, and lower cost relative to dual-labeled probes. The seven DNA Detection Switch (DDS)-probe systems reported here employ two interacting polynucleotide components: a fluorescently labeled probe and a quencher antiprobe. High-fidelity detection is achieved with three DDS designs: two internal probes (internal DDS and Flip probes) and a primer probe (ZIPR probe), wherein each probe is combined with a carefully engineered, slightly mismatched, error-checking antiprobe. The antiprobe blocks off-target detection over a wide range of temperatures and facilitates multiplexing. Other designs (Universal probe, Half-Universal probe, and MacMan probe) use generic components that enable low-cost detection. Finally, single-molecule G-Force probes employ guanine-mediated fluorescent quenching by forming a hairpin between adjacent C-rich and G-rich sequences. Examples provided show how these probe technologies discriminate drug-resistant Mycobacterium tuberculosis mutants, Escherichia coli O157:H7, oncogenic EGFR deletion mutations, hepatitis B virus, influenza A/B strains, and single-nucleotide polymorphisms in the human VKORC1 gene. Copyright © 2014 American Society for Investigative Pathology and the Association for Molecular Pathology. Published by Elsevier Inc. All rights reserved.

  10. IVVS probe mechanical concept design

    Energy Technology Data Exchange (ETDEWEB)

    Rossi, Paolo, E-mail: paolo.rossi@enea.it; Neri, Carlo; De Collibus, Mario Ferri; Mugnaini, Giampiero; Pollastrone, Fabio; Crescenzi, Fabio

    2015-10-15

    Highlights: • ENEA designed, developed and tested a laser based In Vessel Viewing System (IVVS). • IVVS mechanical design has been revised from 2011 to 2013 to meet ITER requirements. • Main improvements are piezoceramic actuators and a step focus system. • Successful qualification activities validated the concept design for ITER environment. - Abstract: ENEA has been deeply involved in the design, development and testing of a laser based In Vessel Viewing System (IVVS) required for the inspection of ITER plasma-facing components. The IVVS probe shall be deployed into the vacuum vessel, providing high resolution images and metrology measurements to detect damages and possible erosion. ENEA already designed and manufactured an IVVS probe prototype based on a rad-hard concept and driven by commercial micro-step motors, which demonstrated satisfying viewing and metrology performances at room conditions. The probe sends a laser beam through a reflective rotating prism. By rotating the axes of the prism, the probe can scan all the environment points except those present in a shadow cone and the backscattered light signal is then processed to measure the intensity level (viewing) and the distance from the probe (metrology). During the last years, in order to meet all the ITER environmental conditions, such as high vacuum, gamma radiation lifetime dose up to 5 MGy, cumulative neutron fluence of about 2.3 × 10{sup 17} n/cm{sup 2}, temperature of 120 °C and magnetic field of 8 T, the probe mechanical design was significantly revised introducing a new actuating system based on piezo-ceramic actuators and improved with a new step focus system. The optical and mechanical schemes have been then modified and refined to meet also the geometrical constraints. The paper describes the mechanical concept design solutions adopted in order to fulfill IVVS probe functional performance requirements considering ITER working environment and geometrical constraints.

  11. Efficient atom localization via probe absorption in an inverted-Y atomic system

    Science.gov (United States)

    Wu, Jianchun; Wu, Bo; Mao, Jiejian

    2018-06-01

    The behaviour of atom localization in an inverted-Y atomic system is theoretically investigated. For the atoms interacting with a weak probe field and several orthogonal standing-wave fields, their position information can be obtained by measuring the probe absorption. Compared with the traditional scheme, we couple the probe field to the transition between the middle and top levels. It is found that the probe absorption sensitively depends on the detuning and strength of the relevant light fields. Remarkably, the atom can be localized at a particular position in the standing-wave fields by coupling a microwave field to the transition between the two ground levels.

  12. Interstellar Probe: First Step to the Stars

    Science.gov (United States)

    McNutt, R. L., Jr.

    2017-12-01

    The idea of an "Interstellar Probe," a robotic spacecraft traveling into the nearby interstellar medium for the purpose of scientific investigation, dates to the mid-1960s. The Voyager Interstellar Mission (VIM), an "accidental" 40-year-old by-product of the Grand Tour of the solar system, has provided initial answers to the problem of the global heliospheric configuration and the details of its interface with interstellar space. But the twin Voyager spacecraft have, at most, only another decade of lifetime, and only Voyager 1 has emerged from the heliosheath interaction region. To understand the nature of the interaction, a near-term mission to the "near-by" interstellar medium with modern and focused instrumentation remains a compelling priority. Imaging of energetic neutral atoms (ENAs) by the Ion Neutral CAmera (INCA) on Cassini and from the Interstellar Boundary Explorer (IBEX) in Earth orbit have provided significant new insights into the global interaction region but point to discrepancies with our current understanding. Exploring "as far as possible" into "pristine" interstellar space can resolve these. Hence, reaching large heliocentric distances rapidly is a driver for an Interstellar Probe. Such a mission is timely; understanding the interstellar context of exoplanet systems - and perhaps the context for the emergence of life both here and there - hinges upon what we can discover within our own stellar neighborhood. With current spacecraft technology and high-capability launch vehicles, such as the Space Launch System (SLS), a small, but extremely capable spacecraft, could be dispatched to the near-by interstellar medium with at least twice the speed of the Voyagers. Challenges remain with payload mass and power constraints for optimized science measurements. Mission longevity, as experienced by, but not designed into, the Voyagers, communications capability, and radioisotope power system performance and lifetime are solvable engineering challenges. Such

  13. Eddy-current probe design

    International Nuclear Information System (INIS)

    Kincaid, T.G.; McCary, R.O.

    1983-01-01

    This paper describes theoretical and experimental work directed toward finding the optimum probe dimensions and operating frequency for eddy current detection of half-penny surface cracks in nonmagnetic conducting materials. The study applies to probes which excite an approximately uniform spatial field over the length of the crack at the surface of the material. In practical terms, this means that the probe is not smaller than the crack length in any of its critical dimensions. The optimization of a simple coil probe is first analyzed in detail. It is shown that signal-to-noise ratio and lift-off discrimination are maximized by a pancake coil with mean radius not greater than the crack length, operated at a frequency which gives a skin depth equal to the crack depth. The results obtained for the simple coil are then used as a basis for discussion of the design of coils with ferrite cores and shields, and for the design of recording head type probes

  14. Nanomaterials and MRI molecular probe

    International Nuclear Information System (INIS)

    Inubushi, Toshiro

    2008-01-01

    This paper presents the current state and future prospect of enhancing probes in MRI which enable to image specific cells and molecules mainly from the aspect of cell trafficking. Although MRI requires such probes for specific imaging, it has an advantage that anatomical images are simultaneously available even during surgical operation without radiation exposure, differing from X-CT, -transillumination and positron emission tomography (PET). In the development of novel MRI molecular probes, the recent topic concerns the cell trafficking biology where cells related with transplantation and immunological therapy can be traced. Although superparamagnetic iron oxide (SPIO) has been used as a commercially available enhancer, this nanoparticle has problems like a difficulty to penetrate cell, cytotoxicity and others. For these, authors have developed the nanoparticle SPIO covered with silica shell, which can be chemically modified, e.g., by binding fluorescent pigments to possibly allow MR bimodal molecular imaging. For penetration of particles in cells, envelop of Sendai virus is used. PET-CT has been more popular these days; however, MRI is superior to CT for imaging soft tissues, and development of PET-MRI is actively under progress aiming the multi-modal imaging. At present, molecular probes for MRI are certainly not so many as those for PET and cooperative efforts to develop the probes are required in medical, technological and pharmaceutical fields. (R.T.)

  15. Electroweak probes with ATLAS

    CERN Document Server

    Milov, Alexander; The ATLAS collaboration

    2018-01-01

    Measuring electroweak bosons in relativistic heavy ion collisions at high energy provide an opportunity to understand temporal evolution of the quark-gluon plasma created in such collisions by constraining the initial state of the interaction. Due to lack of colour charges the bosons and or particles produced in their leptonic decays are unaffected by the quark-gluon plasma and therefore preserve the information about the very early stage of the collision when they were born. This singles EW bosons as a unique and very interesting class of observables in HI collisions. The ATLAS experiment at LHC measures production of electroweak bosons in $pp$, $p$+Pb and Pb+Pb collisions systems. A review of the existing results is given in this proceeding that includes studies made with isolated photons to constraint kinematic properties and flavour composition of associated jets, measurements of $W$ and $Z$ bosons used to estimate nuclear modification of PDF and the production rates of the bosons used to verify geometric...

  16. Label-free biosensing with functionalized nanopipette probes.

    Science.gov (United States)

    Umehara, Senkei; Karhanek, Miloslav; Davis, Ronald W; Pourmand, Nader

    2009-03-24

    Nanopipette technology can uniquely identify biomolecules such as proteins based on differences in size, shape, and electrical charge. These differences are determined by the detection of changes in ionic current as the proteins interact with the nanopipette tip coated with probe molecules. Here we show that electrostatic, biotin-streptavidin, and antibody-antigen interactions on the nanopipette tip surface affect ionic current flowing through a 50-nm pore. Highly charged polymers interacting with the glass surface modulated the rectification property of the nanopipette electrode. Affinity-based binding between the probes tethered to the surface and their target proteins caused a change in the ionic current due to a partial blockade or an altered surface charge. These findings suggest that nanopipettes functionalized with appropriate molecular recognition elements can be used as nanosensors in biomedical and biological research.

  17. Exciton-controlled fluorescence: application to hybridization-sensitive fluorescent DNA probe.

    Science.gov (United States)

    Okamoto, Akimitsu; Ikeda, Shuji; Kubota, Takeshi; Yuki, Mizue; Yanagisawa, Hiroyuki

    2009-01-01

    A hybridization-sensitive fluorescent probe has been designed for nucleic acid detection, using the concept of fluorescence quenching caused by the intramolecular excitonic interaction of fluorescence dyes. We synthesized a doubly thiazole orange-labeled nucleotide showing high fluorescence intensity for a hybrid with the target nucleic acid and effective quenching for the single-stranded state. This exciton-controlled fluorescent probe was applied to living HeLa cells using microinjection to visualize intracellular mRNA localization. Immediately after injection of the probe into the cell, fluorescence was observed from the probe hybridizing with the target RNA. This fluorescence rapidly decreased upon addition of a competitor DNA. Multicoloring of this probe resulted in the simple simultaneous detection of plural target nucleic acid sequences. This probe realized a large, rapid, reversible change in fluorescence intensity in sensitive response to the amount of target nucleic acid, and facilitated spatiotemporal monitoring of the behavior of intracellular RNA.

  18. Gamma-ray imaging probes

    International Nuclear Information System (INIS)

    Wild, W.J.

    1988-01-01

    External nuclear medicine diagnostic imaging of early primary and metastatic lung cancer tumors is difficult due to the poor sensitivity and resolution of existing gamma cameras. Nonimaging counting detectors used for internal tumor detection give ambiguous results because distant background variations are difficult to discriminate from neighboring tumor sites. This suggests that an internal imaging nuclear medicine probe, particularly an esophageal probe, may be advantageously used to detect small tumors because of the ability to discriminate against background variations and the capability to get close to sites neighboring the esophagus. The design, theory of operation, preliminary bench tests, characterization of noise behavior and optimization of such an imaging probe is the central theme of this work

  19. Scanning vector Hall probe microscopy

    International Nuclear Information System (INIS)

    Cambel, V.; Gregusova, D.; Fedor, J.; Kudela, R.; Bending, S.J.

    2004-01-01

    We have developed a scanning vector Hall probe microscope for mapping magnetic field vector over magnetic samples. The microscope is based on a micromachined Hall sensor and the cryostat with scanning system. The vector Hall sensor active area is ∼5x5 μm 2 . It is realized by patterning three Hall probes on the tilted faces of GaAs pyramids. Data from these 'tilted' Hall probes are used to reconstruct the full magnetic field vector. The scanning area of the microscope is 5x5 mm 2 , space resolution 2.5 μm, field resolution ∼1 μT Hz -1/2 at temperatures 10-300 K

  20. Spaser as a biological probe

    Science.gov (United States)

    Galanzha, Ekaterina I.; Weingold, Robert; Nedosekin, Dmitry A.; Sarimollaoglu, Mustafa; Nolan, Jacqueline; Harrington, Walter; Kuchyanov, Alexander S.; Parkhomenko, Roman G.; Watanabe, Fumiya; Nima, Zeid; Biris, Alexandru S.; Plekhanov, Alexander I.; Stockman, Mark I.; Zharov, Vladimir P.

    2017-06-01

    Understanding cell biology greatly benefits from the development of advanced diagnostic probes. Here we introduce a 22-nm spaser (plasmonic nanolaser) with the ability to serve as a super-bright, water-soluble, biocompatible probe capable of generating stimulated emission directly inside living cells and animal tissues. We have demonstrated a lasing regime associated with the formation of a dynamic vapour nanobubble around the spaser that leads to giant spasing with emission intensity and spectral width >100 times brighter and 30-fold narrower, respectively, than for quantum dots. The absorption losses in the spaser enhance its multifunctionality, allowing for nanobubble-amplified photothermal and photoacoustic imaging and therapy. Furthermore, the silica spaser surface has been covalently functionalized with folic acid for molecular targeting of cancer cells. All these properties make a nanobubble spaser a promising multimodal, super-contrast, ultrafast cellular probe with a single-pulse nanosecond excitation for a variety of in vitro and in vivo biomedical applications.

  1. DNA Probe for Lactobacillus delbrueckii

    Science.gov (United States)

    Delley, Michèle; Mollet, Beat; Hottinger, Herbert

    1990-01-01

    From a genomic DNA library of Lactobacillus delbrueckii subsp. bulgaricus, a clone was isolated which complements a leucine auxotrophy of an Escherichia coli strain (GE891). Subsequent analysis of the clone indicated that it could serve as a specific DNA probe. Dot-blot hybridizations with over 40 different Lactobacillus strains showed that this clone specifically recognizes L. delbrueckii subsp. delbrueckii, bulgaricus, and lactis. The sensitivity of the method was tested by using an α-32P-labeled DNA probe. Images PMID:16348233

  2. Architectural Probes of the Infraordinary

    DEFF Research Database (Denmark)

    Lunde Nielsen, Espen

    2017-01-01

    of the city plays a vital role for the social coexistence of and the correlation between its inhabitants. In an era of explosive growth of our cities, it is crucial to critically examine the everyday social dimension, if our cities are to be liveable in the future. To enquire into the everyday topography...... approaches for probing into and interrogating the infraordinary: frameworks of perception and situated probes. Both are deployed in order to get at distance of the familiar and by-pass the usual hierarchies of perception to gain new knowledge. These critical spatial practices span an interdisciplinary...

  3. Detecting device of atomic probe

    International Nuclear Information System (INIS)

    Nikonenkov, N.V.

    1979-01-01

    Operation of an atomic-probe recording device is discussed in detail and its flowsheet is given. The basic elements of the atomic-probe recording device intented for microanalysis of metals and alloys in an atomic level are the storage oscillograph with a raster-sweep unit, a two-channel timer using frequency meters, a digital printer, and a control unit. The digital printer records information supplied by four digital devices (two frequency meters and two digital voltmeters) in a four-digit binary-decimal code. The described device provides simultaneous recording of two ions produced per one vaporation event

  4. Probing nuclear matter with dileptons

    International Nuclear Information System (INIS)

    Schroeder, L.S.

    1986-06-01

    Dileptons are shown to be of interest in helping probe extreme conditions of temperature and density in nuclear matter. The current state of experimental knowledge about dileptons is briefly described, and their use in upcoming experiments with light ions at CERN SPS are reviewed, including possible signatures of quark matter formation. Use of dileptons in an upcoming experiment with a new spectrometer at Berkeley is also discussed. This experiment will probe the nuclear matter equation of state at high temperature and density. 16 refs., 8 figs

  5. Diffusion probe for gas sampling in undisturbed soil

    DEFF Research Database (Denmark)

    Petersen, Søren O

    2014-01-01

    Soil-atmosphere fluxes of trace gases such as methane (CH4) and nitrous oxide (N2O) are determined by complex interactions between biological activity and soil conditions. Soil gas concentration profiles may, in combination with other information about soil conditions, help to understand emission...... controls. This note describes a simple and robust diffusion probe for soil gas sampling as part of flux monitoring programs. It can be deployed with minimum disturbance of in-situ conditions, also at sites with a high or fluctuating water table. Separate probes are used for each sampling depth...... on peat soils used for grazing showed soil gas concentrations of CH4 and N2O as influenced by topography, site conditions, and season. The applicability of the diffusion probe for trace gas monitoring is discussed....

  6. Novel Probes of Gravity and Dark Energy

    Energy Technology Data Exchange (ETDEWEB)

    Jain, Bhuvnesh; et al.

    2013-09-20

    The discovery of cosmic acceleration has stimulated theorists to consider dark energy or modifications to Einstein's General Relativity as possible explanations. The last decade has seen advances in theories that go beyond smooth dark energy -- modified gravity and interactions of dark energy. While the theoretical terrain is being actively explored, the generic presence of fifth forces and dark sector couplings suggests a set of distinct observational signatures. This report focuses on observations that differ from the conventional probes that map the expansion history or large-scale structure. Examples of such novel probes are: detection of scalar fields via lab experiments, tests of modified gravity using stars and galaxies in the nearby universe, comparison of lensing and dynamical masses of galaxies and clusters, and the measurements of fundamental constants at high redshift. The observational expertise involved is very broad as it spans laboratory experiments, high resolution astronomical imaging and spectroscopy and radio observations. In the coming decade, searches for these effects have the potential for discovering fundamental new physics. We discuss how the searches can be carried out using experiments that are already under way or with modest adaptations of existing telescopes or planned experiments. The accompanying paper on the Growth of Cosmic Structure describes complementary tests of gravity with observations of large-scale structure.

  7. Predicting transporter-mediated drug interactions: Commentary on: "Pharmacokinetic evaluation of a drug transporter cocktail consisting of digoxin, furosemide, metformin and rosuvastatin" and "Validation of a microdose probe drug cocktail for clinical drug interaction assessments for drug transporters and CYP3A".

    Science.gov (United States)

    Zhang, L; Sparreboom, A

    2017-04-01

    Transporters, expressed in various tissues, govern the absorption, distribution, metabolism, and excretion of drugs, and consequently their inherent safety and efficacy profiles. Drugs may interact with a transporter as a substrate and/or an inhibitor. Understanding transporter-mediated drug-drug interactions (DDIs), in addition to enzyme-mediated DDIs, is an integral part of risk assessment in drug development and regulatory review because the concomitant use of more than one medication in patients is common. © 2016 ASCPT.

  8. Characterization of near-field optical probes

    DEFF Research Database (Denmark)

    Vohnsen, Brian; Bozhevolnyi, Sergey I.

    1999-01-01

    Radiation and collection characteristics of four different near-field optical-fiber probes, namely, three uncoated probes and an aluminium-coated small-aperture probe, are investigated and compared. Their radiation properties are characterized by observation of light-induced topography changes...... in a photo-sensitive film illuminated with the probes, and it is confirmed that the radiated optical field is unambigiously confined only for the coated probe. Near-field optical imaging of a standing evanescent-wave pattern is used to compare the detection characteristics of the probes, and it is concluded...... that, for the imaging of optical-field intensity distributions containing predominantly evanescent-wave components, a sharp uncoated tip is the probe of choice. Complementary results obtained with optical phase-conjugation experiments with he uncoated probes are discussed in relation to the probe...

  9. PROBES, POPULATIONS, SAMPLES, MEASUREMENTS AND RELATIONS IN STEREOLOGY

    Directory of Open Access Journals (Sweden)

    Robert T Dehoff

    2011-05-01

    Full Text Available This summary paper provides an overview of the content of stereology. The typical problem at hand centers around some three dimensional object that has an internal structure that determines its function, performance, or response. To understand and quantify the geometry of that structure it is necessary to probe it with geometric entities: points, lines, planes volumes, etc. Meaningful results are obtained only if the set of probes chosen for use in the assessment is drawn uniformly from the population of such probes for the structure as a whole. This requires an understanding of the population of each kind of probe. Interaction of the probes with the structure produce geometric events which are the focus of stereological measurements. In almost all applications the measurement that is made is a simple count of the number of these events. Rigorous application of these requirements for sample design produce unbiased estimates of geometric properties of features in the structure no matter how complex are the features or what their arrangement in space. It is this assumption-free characteristic of the methodology that makes it a powerful tool for characterizing the internal structure of three dimensional objects.

  10. Mapping Rotational Wavepacket Dynamics with Chirped Probe Pulses

    Science.gov (United States)

    Romanov, Dmitri; Odhner, Johanan; Levis, Robert

    2014-05-01

    We develop an analytical model description of the strong-field pump-probe polarization spectroscopy of rotational transients in molecular gases in a situation when the probe pulse is considerably chirped: the frequency modulation over the pulse duration is comparable with the carrier frequency. In this scenario, a femtosecond pump laser pulse prepares a rotational wavepacket in a gas-phase sample at room temperature. The rotational revivals of the wavepacket are then mapped onto a chirped broadband probe pulse derived from a laser filament. The slow-varying envelope approximation being inapplicable, an alternative approach is proposed which is capable of incorporating the substantial chirp and the related temporal dispersion of refractive indices. Analytical expressions are obtained for the probe signal modulation over the interaction region and for the resulting heterodyned transient birefringence spectra. Dependencies of the outputs on the probe pulse parameters reveal the trade-offs and the ways to optimize the temporal-spectral imaging. The results are in good agreement with the experiments on snapshot imaging of rotational revival patterns in nitrogen gas. We gratefully acknowledge financial support through AFOSR MURI Grant No. FA9550-10-1-0561.

  11. Probing QCD and new physics with dijets

    CERN Multimedia

    CERN. Geneva

    2014-01-01

    Dijets are the most abundant final state in hadron collisions. During the last 30 years dijets have been used to probe QCD and also search for new phenomena beyond the Standard Model. Recent results from Tevatron and LHC are discussed that reveal the full physics potential of dijets. Precise measurements of cross sections and angular observables, made possible thanks to the excellent understanding of the jet objects, confront the perturbative QCD predictions at the multi-TeV regime and constrain the PDFs. At the same time, the dijet invariant mass spectrum is used as a means of searching for resonances and for contact interactions between the quarks. Following the success of the LHC Run I physics program, dijets will once again play a central role in the quest for exciting discoveries at Run II, and we are prepared to exploit this powerful final state.

  12. Granular Gases: Probing the Boundaries of Hydrodynamics

    International Nuclear Information System (INIS)

    Goldhirsch, I.

    1999-01-01

    The dissipative nature of the particle interactions in granular systems renders granular gases mesoscopic and bearing some similarities to regular gases in the ''continuum transition regime'' where shear rates and/or thermal gradients are very large). The following properties of granular gases support the above claim: (i). Mean free times are of the same order as macroscopic time scales (inverse shear rates); (ii). Mean free paths can be macroscopic and comparable to the system's dimensions; (iii). Typical flows are supersonic; (iv). Shear rates are typically ''large''; (v). Stress fields are scale (resolution) dependent; (vi). Burnett and super-Burnett corrections to both the constitutive relations and the boundary conditions are of importance; (vii). Single particle distribution functions can be far from Gaussian. It is concluded that while hydrodynamic descriptions of granular gases are relevant, they are probing the boundaries of applicability of hydrodynamics and perhaps slightly beyond

  13. Unparticles: Scales and high energy probes

    International Nuclear Information System (INIS)

    Bander, Myron; Feng, Jonathan L.; Rajaraman, Arvind; Shirman, Yuri

    2007-01-01

    Unparticles from hidden conformal sectors provide qualitatively new possibilities for physics beyond the standard model. In the theoretical framework of minimal models, we clarify the relation between energy scales entering various phenomenological analyses. We show that these relations always counteract the effective field theory intuition that higher dimension operators are more highly suppressed, and that the requirement of a significant conformal window places strong constraints on possible unparticle signals. With these considerations in mind, we examine some of the most robust and sensitive probes and explore novel effects of unparticles on gauge coupling evolution and fermion production at high energy colliders. These constraints are presented both as bounds on four-fermion interaction scales and as constraints on the fundamental parameter space of minimal models

  14. Nuclear physics with electroweak probes

    International Nuclear Information System (INIS)

    Benhar, Omar

    2009-01-01

    In recent years, the italian theoretical Nuclear Physics community has played a leading role in the development of a unified approach, allowing for a consistent and fully quantitative description of the nuclear response to electromagnetic and weak probes. In this paper I review the main achievements in both fields, point out some of the open problems, and outline the most promising prospects

  15. Resolution analysis by random probing

    NARCIS (Netherlands)

    Fichtner, Andreas; van Leeuwen, T.

    2015-01-01

    We develop and apply methods for resolution analysis in tomography, based on stochastic probing of the Hessian or resolution operators. Key properties of our methods are (i) low algorithmic complexity and easy implementation, (ii) applicability to any tomographic technique, including full‐waveform

  16. A fluorescent probe for ecstasy.

    Science.gov (United States)

    Masseroni, D; Biavardi, E; Genovese, D; Rampazzo, E; Prodi, L; Dalcanale, E

    2015-08-18

    A nanostructure formed by the insertion in silica nanoparticles of a pyrene-derivatized cavitand, which is able to specifically recognize ecstasy in water, is presented. The absence of effects from interferents and an efficient electron transfer process occurring after complexation of ecstasy, makes this system an efficient fluorescent probe for this popular drug.

  17. Probing Pharmaceutical Mixtures during Milling

    DEFF Research Database (Denmark)

    Walker, Greg; Römann, Philipp; Poller, Bettina

    2017-01-01

    interpret the spectral changes. Overall, this study demonstrates the potential of low-frequency Raman spectroscopy, which has several practical advantages over XRPD, for probing (dis-)order during pharmaceutical processing, showcasing its potential for future development, and implementation as an in...

  18. Probing phonons in plutonium

    International Nuclear Information System (INIS)

    Wong, Joe; Krisch, M.; Farber, D.; Occelli, F.; Schwartz, A.; Chiang, T.C.; Wall, M.; Boro, C.; Xu, Ruqing

    2010-01-01

    ) capability on ID28. The complete PDCs for an fcc Pu-0.6 wt% Ga alloy are plotted in Figure 2, and represent the first full set of phonon dispersions ever determined for any Pu-bearing materials. The solid curves (red) are calculated using a standard Born-von Karman (B-vK) force constant model. An adequate fit to the experimental data is obtained if interactions up to the fourth-nearest neighbours are included. The dashed curves (blue) are recent dynamical mean field theory (DMFT) results by Dai et al. The elastic moduli calculated from the slopes of the experimental phonon dispersion curves near the Λ point are: C 11 = 35.3 ± 1.4 GPa, C 12 = 25.5 ± 1.5 GPa and C 44 = 30.53 ± 1.1 GPa. These values are in excellent agreement with those of the only other measurement on a similar alloy (1 wt % Ga) using ultrasonic techniques as well as with those recently calculated from a combined DMFT and linear response theory for pure (delta)-Pu. Several unusual features, including a large elastic anisotropy, a small shear elastic modulus C(prime), a Kohn-like anomaly in the T 1 [011] branch, and a pronounced softening of the [111] transverse modes are found. These features can be related to the phase transitions of plutonium and to strong coupling between the lattice structure and the 5f valence instabilities. The HRIXS results also provide a critical test for theoretical treatments of highly correlated 5f electron systems as exemplified by recent dynamical mean field theory (DMFT) calculations for (delta)-plutonium. The experimental-theoretical agreements shown in Figure 2 in terms of a low shear elastic modulus C(prime), a Kohn-like anomaly in the T 1 [011] branch, and a large softening of the T[111] modes give credence to the DMFT approach for the theoretical treatment of 5f electron systems of which (delta)-Pu is a classic example. However, quantitative differences remain. These are the position of the Kohn anomaly along the T 1 [011] branch, the energy maximum of the T[111] mode s

  19. Contamination-free sounding rocket Langmuir probe

    Science.gov (United States)

    Amatucci, W. E.; Schuck, P. W.; Walker, D. N.; Kintner, P. M.; Powell, S.; Holback, B.; Leonhardt, D.

    2001-04-01

    A technique for removing surface contaminants from a sounding rocket spherical Langmuir probe is presented. Contamination layers present on probe surfaces can skew the collected data, resulting in the incorrect determination of plasma parameters. Despite following the usual probe cleaning techniques that are used prior to a launch, the probe surface can become coated with layers of adsorbed neutral gas in less than a second when exposed to atmosphere. The laboratory tests reported here show that by heating the probe from the interior using a small halogen lamp, adsorbed neutral particles can be removed from the probe surface, allowing accurate plasma parameter measurements to be made.

  20. Hydrogen interaction with oxidized Si(111) probed with positrons

    International Nuclear Information System (INIS)

    Lynn, K.G.; Nielsen, B.; Welch, D.O.

    1989-01-01

    A variable-energy positron beam was utilized to study the interface action of hydrogen with Si(111) covered by an ultrahigh-vacuum thermally grown oxide of 2-3 nm thickness. It was observed that positrons implanted at shallow depth (< 100 nm) after diffusion are trapped either at the interface between the oxide and the Si or in the oxide. The positron-annihilation characteristics of these trapped positrons are found to be very sensitive to hydrogen exposure. The momentum distribution of the annihilating positron-electron pair, as observed in the Doppler broadening of the annihilation line, broadens considerably after exposure to hydrogen. The effect recovers after annealing at ≅ 1100 K, suggesting a hydrogen binding at the interface of ∼ 3 ± 0.3 eV. (author). 18 refs., 3 figs

  1. Higgs production as a probe of dark energy interactions

    International Nuclear Information System (INIS)

    Brax, Philippe; Davis, Anne-Christine; Seery, David

    2009-11-01

    We study Higgs production under the influence of a light, scalar dark energy field with chameleon-like couplings to matter. Our analysis is relevant for hadron colliders, such as the Large Hadron Collider, which are expected to manufacture Higgs particles through weak boson fusion, or associated production with a Z or W ± . We show that the corrections arising in these models are too small to be observed. This result can be attributed to the gauge invariance of the low energy Lagrangian. As a by-product of our analysis, we provide the first microphysical realization of a dark energy model coupled to the electromagnetic field strength. In models where dark energy couples to all matter species in a uniform manner we are able to give a new, stringent bound on its coupling strength. (orig.)

  2. Higgs production as a probe of dark energy interactions

    CERN Document Server

    Brax, Philippe; Davis, Anne-Christine; Seery, David; Weltman, Amanda

    2010-01-01

    We study Higgs production under the influence of a light, scalar dark energy field with chameleon-like couplings to matter. Our analysis is relevant for hadron colliders, such as the Large Hadron Collider, which are expected to manufacture Higgs particles through weak boson fusion, or associated production with a Z or W. We show that the corrections arising in these models are too small to be observed. This result can be attributed to the gauge invariance of the low energy Lagrangian. As a by-product of our analysis, we provide the first microphysical realization of a dark energy model coupled to the electromagnetic field strength. In models where dark energy couples to all matter species in a uniform manner we are able to give a new, stringent bound on its coupling strength.

  3. The interaction of fluorescent nanodiamond probes with cellular media

    NARCIS (Netherlands)

    Hemelaar, Simon R; Nagl, Andreas; Bigot, François; Rodriquez Garcia, Melissa; de Vries, Marcel P; Chipaux, Mayeul; Schirhagl, Romana

    Fluorescent nanodiamonds (FNDs) are promising tools to image cells, bioanalytes and physical quantities such as temperature, pressure, and electric or magnetic fields with nanometer resolution. To exploit their potential for intracellular applications, the FNDs have to be brought into contact with

  4. Isospin Symmetry of Transitions Probed by Weak and Strong Interactions

    CERN Multimedia

    Roeckl, E

    2002-01-01

    Under the assumption that isospin is a good quantum number, isospin symmetry is expected for the transitions from the ground states of the pair of T = 1, T$_{z}$ = $\\pm$ 1 nuclei to excited states of the T = 0 nucleus situated in between the pair. In order to study the isospin symmetry of these transitions, we propose to perform an accurate comparison of Gamow-Teller (GT) transitions for the A = 58 system. This system is the heaviest for which such a comparison is possible. The $^{58}$Ni(T$_{z}$ = 1 ) $\\rightarrow^{58}$Cu(T$_{z}$ = 0 ) GT transitions are presently studied by using high-resolution charge exchange reaction at RNCP Osaka, while those of $^{58}$Zn(T$_{z}$ = -1) $\\rightarrow^{58}$Cu will be investigated in the $\\beta$-decay study at ISOLDE. Due to the large $Q\\scriptstyle_\\textrm{EC}$-value of $^{58}$Zn, GT transitions can be observed up to high excitation energies in $^{58}$Cu. In order to reach this goal, it is proposed to measure $\\beta$-delayed protons and $\\gamma$-rays by using a dedicated de...

  5. Higgs production as a probe of dark energy interactions

    Energy Technology Data Exchange (ETDEWEB)

    Brax, Philippe [CEA, IPhT, CNRS, URA2306, Gif-sur-Yvette (France). Inst. de Physique Theorique; Burrage, Clare [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Davis, Anne-Christine; Seery, David [Cambridge Univ. (United Kingdom). Dept. of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences; Weltmann, Amanda [Cambridge Univ. (United Kingdom). Dept. of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences; Cape Town Univ. (South Africa). Dept. of Mathematics and Applied Mathematics; Centre for Theoretical Cosmology Fellow, Cambridge (United Kingdom)

    2009-11-15

    We study Higgs production under the influence of a light, scalar dark energy field with chameleon-like couplings to matter. Our analysis is relevant for hadron colliders, such as the Large Hadron Collider, which are expected to manufacture Higgs particles through weak boson fusion, or associated production with a Z or W{sup {+-}}. We show that the corrections arising in these models are too small to be observed. This result can be attributed to the gauge invariance of the low energy Lagrangian. As a by-product of our analysis, we provide the first microphysical realization of a dark energy model coupled to the electromagnetic field strength. In models where dark energy couples to all matter species in a uniform manner we are able to give a new, stringent bound on its coupling strength. (orig.)

  6. Probing Interactions in Complex Molecular Systems through Ordered Assembly

    International Nuclear Information System (INIS)

    De Yoreo, J.J.; Bartelt, M.C.; Orme, C.A.; Villacampa, A.; Weeks, B.L.; Miller, A.E.

    2002-01-01

    Emerging from the machinery of epitaxial science and chemical synthesis, is a growing emphasis on development of self-organized systems of complex molecular species. The nature of self-organization in these systems spans the continuum from simple crystallization of large molecules such as dendrimers and proteins, to assembly into large organized networks of nanometer-scale structures such as quantum dots or nanoparticles. In truth, self-organization in complex molecular systems has always been a central feature of many scientific disciplines including fields as diverse as structural biology, polymer science and geochemistry. But over the past decade, changes in those fields have often been marked by the degree to which researchers are using molecular-scale approaches to understand the hierarchy of structures and processes driven by this ordered assembly. At the same time, physical scientists have begun to use their knowledge of simple atomic and molecular systems to fabricate synthetic self-organized systems. This increasing activity in the field of self-organization is testament to the success of the physical and chemical sciences in building a detailed understanding of crystallization and epitaxy in simple atomic and molecular systems, one that is soundly rooted in thermodynamics and chemical kinetics. One of the fundamental challenges of chemistry and materials science in the coming decades is to develop a similarly well-founded physical understanding of assembly processes in complex molecular systems. Over the past five years, we have successfully used in situ atomic force microscopy (AFM) to investigate the physical controls on single crystal epitaxy from solutions for a wide range of molecular species. More recently, we have combined this method with grazing incidence X-ray diffraction and kinetic Monte Carlo modeling in order to relate morphology to surface atomic structure and processes. The purpose of this proposal was to extend this approach to assemblies of three classes of ''super molecular'' nanostructured materials. These included (1) dendrimers, (2) DNA bonded nano-particles, and (3) colloids, all of which form solution-based self-organizing systems. To this end, our goals were, first, to learn how to modify models of epitaxy in small molecule systems so that they are useful, efficient, and applicable to assembly of super-molecular species; and, second, to learn how systematic variations in the structure and bonding of the building blocks affect the surface kinetics and energetics that control the assembly process and the subsequent dynamic behavior of the assembled structures. AFM imaging provided experimental data on morphology and kinetics, while kinetic Monte Carlo (KMC) simulations related these data to molecular-scale processes and features

  7. A Pan-GTPase Inhibitor as a Molecular Probe.

    Directory of Open Access Journals (Sweden)

    Lin Hong

    Full Text Available Overactive GTPases have often been linked to human diseases. The available inhibitors are limited and have not progressed far in clinical trials. We report here a first-in-class small molecule pan-GTPase inhibitor discovered from a high throughput screening campaign. The compound CID1067700 inhibits multiple GTPases in biochemical, cellular protein and protein interaction, as well as cellular functional assays. In the biochemical and protein interaction assays, representative GTPases from Rho, Ras, and Rab, the three most generic subfamilies of the GTPases, were probed, while in the functional assays, physiological processes regulated by each of the three subfamilies of the GTPases were examined. The chemical functionalities essential for the activity of the compound were identified through structural derivatization. The compound is validated as a useful molecular probe upon which GTPase-targeting inhibitors with drug potentials might be developed.

  8. Cantilevered probe detector with piezoelectric element

    Science.gov (United States)

    Adams, Jesse D; Sulchek, Todd A; Feigin, Stuart C

    2013-04-30

    A disclosed chemical detection system for detecting a target material, such as an explosive material, can include a cantilevered probe, a probe heater coupled to the cantilevered probe, and a piezoelectric element disposed on the cantilevered probe. The piezoelectric element can be configured as a detector and/or an actuator. Detection can include, for example, detecting a movement of the cantilevered probe or a property of the cantilevered probe. The movement or a change in the property of the cantilevered probe can occur, for example, by adsorption of the target material, desorption of the target material, reaction of the target material and/or phase change of the target material. Examples of detectable movements and properties include temperature shifts, impedance shifts, and resonant frequency shifts of the cantilevered probe. The overall chemical detection system can be incorporated, for example, into a handheld explosive material detection system.

  9. Computer modelling of eddy current probes

    International Nuclear Information System (INIS)

    Sullivan, S.P.

    1992-01-01

    Computer programs have been developed for modelling impedance and transmit-receive eddy current probes in two-dimensional axis-symmetric configurations. These programs, which are based on analytic equations, simulate bobbin probes in infinitely long tubes and surface probes on plates. They calculate probe signal due to uniform variations in conductor thickness, resistivity and permeability. These signals depend on probe design and frequency. A finite element numerical program has been procured to calculate magnetic permeability in non-linear ferromagnetic materials. Permeability values from these calculations can be incorporated into the above analytic programs to predict signals from eddy current probes with permanent magnets in ferromagnetic tubes. These programs were used to test various probe designs for new testing applications. Measurements of magnetic permeability in magnetically biased ferromagnetic materials have been performed by superimposing experimental signals, from special laboratory ET probes, on impedance plane diagrams calculated using these programs. (author). 3 refs., 2 figs

  10. The time domain triple probe method

    International Nuclear Information System (INIS)

    Meier, M.A.; Hallock, G.A.; Tsui, H.Y.W.; Bengtson, R.D.

    1994-01-01

    A new Langmuir probe technique based on the triple probe method is being developed to provide simultaneous measurement of plasma temperature, potential, and density with the temporal and spatial resolution required to accurately characterize plasma turbulence. When the conventional triple probe method is used in an inhomogeneous plasma, local differences in the plasma measured at each probe introduce significant error in the estimation of turbulence parameters. The Time Domain Triple Probe method (TDTP) uses high speed switching of Langmuir probe potential, rather than spatially separated probes, to gather the triple probe information thus avoiding these errors. Analysis indicates that plasma response times and recent electronics technology meet the requirements to implement the TDTP method. Data reduction techniques of TDTP data are to include linear and higher order correlation analysis to estimate fluctuation induced particle and thermal transport, as well as energy relationships between temperature, density, and potential fluctuations

  11. Characterizing nanoscale scanning probes using electron microscopy: A novel fixture and a practical guide

    Energy Technology Data Exchange (ETDEWEB)

    Jacobs, Tevis D. B., E-mail: tjacobs@pitt.edu [Department of Mechanical Engineering and Materials Science, University of Pittsburgh, 3700 O’Hara St., Pittsburgh, Pennsylvania 15208 (United States); Wabiszewski, Graham E.; Goodman, Alexander J.; Carpick, Robert W., E-mail: carpick@seas.upenn.edu [Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, 220 S. 33rd St., Philadelphia, Pennsylvania 19104 (United States)

    2016-01-15

    The nanoscale geometry of probe tips used for atomic force microscopy (AFM) measurements determines the lateral resolution, contributes to the strength of the tip-surface interaction, and can be a significant source of uncertainty in the quantitative analysis of results. While inverse imaging of the probe tip has been used successfully to determine probe tip geometry, direct observation of the tip profile using electron microscopy (EM) confers several advantages: it provides direct (rather than indirect) imaging, requires fewer algorithmic parameters, and does not require bringing the tip into contact with a sample. In the past, EM-based observation of the probe tip has been achieved using ad hoc mounting methods that are constrained by low throughput, the risk of contamination, and repeatability issues. We report on a probe fixture designed for use in a commercial transmission electron microscope that enables repeatable mounting of multiple AFM probes as well as a reference grid for beam alignment. This communication describes the design, fabrication, and advantages of this probe fixture, including full technical drawings for machining. Further, best practices are discussed for repeatable, non-destructive probe imaging. Finally, examples of the fixture’s use are described, including characterization of common commercial AFM probes in their out-of-the-box condition.

  12. Improving the viability and versatility of the E × B probe with an active cooling system

    Science.gov (United States)

    Liu, Lihui; Cai, Guobiao; You, Fengyi; Ren, Xiang; Zheng, Hongru; He, Bijiao

    2018-04-01

    A thermostatic E × B probe is designed to protect the probe body from the thermal effect of the plasma plume that has a significant influence on the resolution of the probe for high-power electric thrusters. An active cooling system, which consists of a cooling panel and carbon fiber felts combined with a recycling system of liquid coolants or an open-type system of gas coolants, is employed to realize the protection of the probe. The threshold for the design parameters for the active cooling system is estimated by deriving the energy transfer of the plasma plume-probe body interaction and the energy taken away by the coolants, and the design details are explained. The diagnostics of the LIPS-300 ion thruster with a power of 3 kW and a screen-grid voltage of 1450 V was implemented by the designed thermostatic E × B probe. The measured spectra illustrate that the thermostatic E × B probe can distinguish the fractions of Xe+ ions and Xe2+ ions without areas of overlap. In addition, the temperature of the probe body was less than 306 K in the beam region of the plasma plume during the 200-min-long continuous test. A thermostatic E × B probe is useful for enhancing the viability and versatility of equipment and for reducing uneconomical and complex test procedures.

  13. Where do pulse oximeter probes break?

    Science.gov (United States)

    Crede, S; Van der Merwe, G; Hutchinson, J; Woods, D; Karlen, W; Lawn, J

    2014-06-01

    Pulse oximetry, a non-invasive method for accurate assessment of blood oxygen saturation (SPO2), is an important monitoring tool in health care facilities. However, it is often not available in many low-resource settings, due to expense, overly sophisticated design, a lack of organised procurement systems and inadequate medical device management and maintenance structures. Furthermore medical devices are often fragile and not designed to withstand the conditions of low-resource settings. In order to design a probe, better suited to the needs of health care facilities in low-resource settings this study aimed to document the site and nature of pulse oximeter probe breakages in a range of different probe designs in a low to middle income country. A retrospective review of job cards relating to the assessment and repair of damaged or faulty pulse oximeter probes was conducted at a medical device repair company based in Cape Town, South Africa, specializing in pulse oximeter probe repairs. 1,840 job cards relating to the assessment and repair of pulse oximeter probes were reviewed. 60.2 % of probes sent for assessment were finger-clip probes. For all probes, excluding the neonatal wrap probes, the most common point of failure was the probe wiring (>50 %). The neonatal wrap most commonly failed at the strap (51.5 %). The total cost for quoting on the broken pulse oximeter probes and for the subsequent repair of devices, excluding replacement components, amounted to an estimated ZAR 738,810 (USD $98,508). Improving the probe wiring would increase the life span of pulse oximeter probes. Increasing the life span of probes will make pulse oximetry more affordable and accessible. This is of high priority in low-resource settings where frequent repair or replacement of probes is unaffordable or impossible.

  14. Probe-based recording technology

    International Nuclear Information System (INIS)

    Naberhuis, Steve

    2002-01-01

    The invention of the scanning tunneling microscope (STM) prompted researchers to contemplate whether such technology could be used as the basis for the storage and retrieval of information. With magnetic data storage technology facing limits in storage density due to the thermal instability of magnetic bits, the super-paramagnetic limit, the heir-apparent for information storage at higher densities appeared to be variants of the STM or similar probe-based storage techniques such as atomic force microscopy (AFM). Among these other techniques that could provide replacement technology for magnetic storage, near-field optical scanning optical microscopy (NSOM or SNOM) has also been investigated. Another alternative probe-based storage technology called atomic resolution storage (ARS) is also currently under development. An overview of these various technologies is herein presented, with an analysis of the advantages and disadvantages inherent in each particularly with respect to reduced device dimensions. The role of micro electro mechanical systems (MEMS) is emphasized

  15. Solar Probe Cup: Laboratory Performance

    Science.gov (United States)

    Case, A. W.; Kasper, J. C.; Korreck, K. E.; Stevens, M. L.; Larson, D. E.; Wright, K. H., Jr.; Gallagher, D. L.; Whittlesey, P. L.

    2017-12-01

    The Solar Probe Cup (SPC) is a Faraday Cup instrument that will fly on the Paker Solar Probe (PSP) spacecraft, orbiting the Sun at as close as 9.86 solar radii. The SPC instrument is designed to measure the thermal solar wind plasma (protons, alphas, and electrons) that will be encountered throughout its close encounter with the Sun. Due to the solar wind flow being primarily radial, the SPC instrument is pointed directly at the Sun, resulting in an extreme thermal environment that must be tolerated throughout the primary data collection phase. Laboratory testing has been performed over the past 6 months to demonstrate the instrument's performance relative to its requirements, and to characterize the measurements over the expected thermal range. This presentation will demonstrate the performance of the instrument as measured in the lab, describe the operational configurations planned for flight, and discuss the data products that will be created.

  16. Electrostatic probes in luminescent discharges

    International Nuclear Information System (INIS)

    Cunha Raposo, C. da.

    1980-01-01

    A system to produce luminescent type plasma by continuos discharge and ionization by high frequency was constructed. The ionization was done in the air and in the argon under pressures from 3 to 10 mmHg. The parameters of a non magnetized collisional plasma and the parameters of a magnetized plasma such as, density, eletron temperature and potential, using a Langmuir probe with plane geometry, were determined. (M.C.K.) [pt

  17. DNA Probe for Lactobacillus delbrueckii

    OpenAIRE

    Delley, Michèle; Mollet, Beat; Hottinger, Herbert

    1990-01-01

    From a genomic DNA library of Lactobacillus delbrueckii subsp. bulgaricus, a clone was isolated which complements a leucine auxotrophy of an Escherichia coli strain (GE891). Subsequent analysis of the clone indicated that it could serve as a specific DNA probe. Dot-blot hybridizations with over 40 different Lactobacillus strains showed that this clone specifically recognizes L. delbrueckii subsp. delbrueckii, bulgaricus, and lactis. The sensitivity of the method was tested by using an α-32P-l...

  18. Atomic beams probe surface vibrations

    International Nuclear Information System (INIS)

    Robinson, A.L.

    1982-01-01

    In the last two years, surface scientist have begun trying to obtain the vibrational frequencies of surface atoms in both insulating and metallic crystals from beams of helium atoms. It is the inelastic scattering that researchers use to probe surface vibrations. Inelastic atomic beam scattering has only been used to obtain vibrational frequency spectra from clean surfaces. Several experiments using helium beams are cited. (SC)

  19. Distance probes of dark energy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, A. G.; Padmanabhan, N.; Aldering, G.; Allen, S. W.; Baltay, C.; Cahn, R. N.; D’Andrea, C. B.; Dalal, N.; Dawson, K. S.; Denney, K. D.; Eisenstein, D. J.; Finley, D. A.; Freedman, W. L.; Ho, S.; Holz, D. E.; Kasen, D.; Kent, S. M.; Kessler, R.; Kuhlmann, S.; Linder, E. V.; Martini, P.; Nugent, P. E.; Perlmutter, S.; Peterson, B. M.; Riess, A. G.; Rubin, D.; Sako, M.; Suntzeff, N. V.; Suzuki, N.; Thomas, R. C.; Wood-Vasey, W. M.; Woosley, S. E.

    2015-03-01

    This document presents the results from the Distances subgroup of the Cosmic Frontier Community Planning Study (Snowmass 2013). We summarize the current state of the field as well as future prospects and challenges. In addition to the established probes using Type Ia supernovae and baryon acoustic oscillations, we also consider prospective methods based on clusters, active galactic nuclei, gravitational wave sirens and strong lensing time delays.

  20. Lasers probe the atomic nucleus

    International Nuclear Information System (INIS)

    Eastham, D.

    1986-01-01

    The article is contained in a booklet on the Revised Nuffield Advanced Physics Course, and concentrates on two techniques to illustrate how lasers probe the atomic nucleus. Both techniques employ resonance fluorescence spectroscopy for obtaining atomic transition energies. The first uses lasers to determine the change in the nuclear charge radius with isotope, the second concerns the use of lasers for ultrasensitive detection of isotopes and elements. The application of lasers in resonance ionization spectroscopy and proton decay is also described. (UK)

  1. Tools to probe the universe

    International Nuclear Information System (INIS)

    Lagage, P.O.; Augueres, J.L.; Amiaux, J.; Cara, Ch.; Fontignie, J.; Rio, Y.; Fermon, C.; Pannetier-Lecoeur, M.; De Vismes, A.; Cordier, B.; Fesquet, M.; Ferrando, Ph.; Authier, M.; Pantin, E.; Glicenstein, J.F.; Boulade, O.; Refregier, A.; Stolarczyk, Th.; Agnese, P.; Rodriguez, L.; Agnese, P.; Pigot, C.; Duband, L.; Limousin, O.; Delagnes, E.; Turck-Chieze, S.; Carton, P.H.; Starck, J.L.; Bournaud, F.; Teyssier, R.; Audit, E.; Brun, A.S.; Leca, P.; Menache, Ch.; Pomarede, D.; Thooris, B.; Meis, C.

    2009-01-01

    This special issue of Clefs CEA journal is entirely devoted to astrophysics and to the exploration and probing of the Universe. The second part of this dossier, described here, makes a status of the tools used to probe the universe: telescopes, imaging spectrometers, data processing and simulation. Content: A - Telescopes of the future: 1. Seeing further out: JWST: looking back on a past 13 billion years old, Space specifics: the learning curve to know-how, Fabricating a corona-graph mask, SVOM, a satellite to detect the explosions of the first stars to be formed in the Universe; 2. Seeing more precisely: SIMBOL-X, pioneering formation flying, ELT/METIS, a 42-meter giant, One hundred telescopes for the CTA arrays; 3. Seeing wider: Euclid, mapping the extragalactic sky, ANTARES: the neutrino, another cosmic messenger; B - The new generation of imaging spectrometers: Observing the Universe in the submillimeter spectral region, The X-ray Universe, Space cryo-coolers, Out in the extreme, tumultuous Universe, Probing the Sun with GOLF-NG, Focus: From light to imagery; C - Data analysis in astrophysics; D - Numerical simulation in astrophysics: Information technology and theoretical predictions in astrophysics, Supercomputers for a better understanding of the Universe, The visualization of astrophysical simulations, Godunov, a numerical platform for education and research

  2. A computerized Langmuir probe system

    International Nuclear Information System (INIS)

    Pilling, L.S.; Bydder, E.L.; Carnegie, D.A.

    2003-01-01

    For low pressure plasmas it is important to record entire single or double Langmuir probe characteristics accurately. For plasmas with a depleted high energy tail, the accuracy of the recorded ion current plays a critical role in determining the electron temperature. Even for high density Maxwellian distributions, it is necessary to accurately model the ion current to obtain the correct electron density. Since the electron and ion current saturation values are, at best, orders of magnitude apart, a single current sensing resistor cannot provide the required resolution to accurately record these values. We present an automated, personal computer based data acquisition system for the determination of fundamental plasma properties in low pressure plasmas. The system is designed for single and double Langmuir probes, whose characteristics can be recorded over a bias voltage range of ±70 V with 12 bit resolution. The current flowing through the probes can be recorded within the range of 5 nA-100 mA. The use of a transimpedance amplifier for current sensing eliminates the requirement for traditional current sensing resistors and hence the need to correct the raw data. The large current recording range is realized through the use of a real time gain switching system in the negative feedback loop of the transimpedance amplifier

  3. A computerized Langmuir probe system

    Science.gov (United States)

    Pilling, L. S.; Bydder, E. L.; Carnegie, D. A.

    2003-07-01

    For low pressure plasmas it is important to record entire single or double Langmuir probe characteristics accurately. For plasmas with a depleted high energy tail, the accuracy of the recorded ion current plays a critical role in determining the electron temperature. Even for high density Maxwellian distributions, it is necessary to accurately model the ion current to obtain the correct electron density. Since the electron and ion current saturation values are, at best, orders of magnitude apart, a single current sensing resistor cannot provide the required resolution to accurately record these values. We present an automated, personal computer based data acquisition system for the determination of fundamental plasma properties in low pressure plasmas. The system is designed for single and double Langmuir probes, whose characteristics can be recorded over a bias voltage range of ±70 V with 12 bit resolution. The current flowing through the probes can be recorded within the range of 5 nA-100 mA. The use of a transimpedance amplifier for current sensing eliminates the requirement for traditional current sensing resistors and hence the need to correct the raw data. The large current recording range is realized through the use of a real time gain switching system in the negative feedback loop of the transimpedance amplifier.

  4. Timing performance of the silicon PET insert probe.

    Science.gov (United States)

    Studen, A; Burdette, D; Chesi, E; Cindro, V; Clinthorne, N H; Cochran, E; Grosicar, B; Kagan, H; Lacasta, C; Linhart, V; Mikuz, M; Stankova, V; Weilhammer, P; Zontar, D

    2010-01-01

    Simulation indicates that PET image could be improved by upgrading a conventional ring with a probe placed close to the imaged object. In this paper, timing issues related to a PET probe using high-resistivity silicon as a detector material are addressed. The final probe will consist of several (four to eight) 1-mm thick layers of silicon detectors, segmented into 1 x 1 mm(2) pads, each pad equivalent to an independent p + nn+ diode. A proper matching of events in silicon with events of the external ring can be achieved with a good timing resolution. To estimate the timing performance, measurements were performed on a simplified model probe, consisting of a single 1-mm thick detector with 256 square pads (1.4 mm side), coupled with two VATAGP7s, application-specific integrated circuits. The detector material and electronics are the same that will be used for the final probe. The model was exposed to 511 keV annihilation photons from an (22)Na source, and a scintillator (LYSO)-PMT assembly was used as a timing reference. Results were compared with the simulation, consisting of four parts: (i) GEANT4 implemented realistic tracking of electrons excited by annihilation photon interactions in silicon, (ii) calculation of propagation of secondary ionisation (electron-hole pairs) in the sensor, (iii) estimation of the shape of the current pulse induced on surface electrodes and (iv) simulation of the first electronics stage. A very good agreement between the simulation and the measurements were found. Both indicate reliable performance of the final probe at timing windows down to 20 ns.

  5. Influence of probe geometry on the response of an electrostatic probe

    DEFF Research Database (Denmark)

    Johansson, Torben; Crichton, George C; McAllister, Iain Wilson

    1999-01-01

    The response of an electrostatic probe is examined with reference to the probe geometry. The study involves the evaluation of the probe lambda function, from which response-related characteristic parameters can be derived. These parameters enable the probe detection sensitivity Se and spatial...

  6. Sensor Interaction as a Source of the Electromagnetic Field Measurement Error

    Directory of Open Access Journals (Sweden)

    Hartansky R.

    2014-12-01

    Full Text Available The article deals with analytical calculation and numerical simulation of interactive influence of electromagnetic sensors. Sensors are components of field probe, whereby their interactive influence causes the measuring error. Electromagnetic field probe contains three mutually perpendicular spaced sensors in order to measure the vector of electrical field. Error of sensors is enumerated with dependence on interactive position of sensors. Based on that, proposed were recommendations for electromagnetic field probe construction to minimize the sensor interaction and measuring error.

  7. Zero voltage mass spectrometry probes and systems

    Science.gov (United States)

    Cooks, Robert Graham; Wleklinski, Michael Stanley; Bag, Soumabha; Li, Yafeng

    2017-10-10

    The invention generally relates to zero volt mass spectrometry probes and systems. In certain embodiments, the invention provides a system including a mass spectrometry probe including a porous material, and a mass spectrometer (bench-top or miniature mass spectrometer). The system operates without an application of voltage to the probe. In certain embodiments, the probe is oriented such that a distal end faces an inlet of the mass spectrometer. In other embodiments, the distal end of the probe is 5 mm or less from an inlet of the mass spectrometer.

  8. Probing cellular behaviors through nanopatterned chitosan membranes

    International Nuclear Information System (INIS)

    Yang, Chung-Yao; Sung, Chun-Yen; Shuai, Hung-Hsun; Cheng, Chao-Min; Yeh, J Andrew

    2013-01-01

    This paper describes a high-throughput method for developing physically modified chitosan membranes to probe the cellular behavior of MDCK epithelial cells and HIG-82 fibroblasts adhered onto these modified membranes. To prepare chitosan membranes with micro/nanoscaled features, we have demonstrated an easy-to-handle, facile approach that could be easily integrated with IC-based manufacturing processes with mass production potential. These physically modified chitosan membranes were observed by scanning electron microscopy to gain a better understanding of chitosan membrane surface morphology. After MDCK cells and HIG-82 fibroblasts were cultured on these modified chitosan membranes for various culture durations (i.e. 1, 2, 4, 12 and 24 h), they were investigated to decipher cellular behavior. We found that both cells preferred to adhere onto a flat surface rather than on a nanopatterned surface. However, most (> 80%) of the MDCK cells showed rounded morphology and would suspend in the cultured medium instead of adhering onto the planar surface of negatively nanopatterned chitosan membranes. This means different cell types (e.g. fibroblasts versus epithelia) showed distinct capabilities/preferences of adherence for materials of varying surface roughness. We also showed that chitosan membranes could be re-used at least nine times without significant contamination and would provide us consistency for probing cell–material interactions by permitting reuse of the same substrate. We believe these results would provide us better insight into cellular behavior, specifically, microscopic properties and characteristics of cells grown under unique, nanopatterned cell-interface conditions. (paper)

  9. TORE SUPRA fast reciprocating radio frequency probe

    International Nuclear Information System (INIS)

    Thomas, C.E. Jr.; Harris, J.H.; Haste, G.R.; Kwon, M.; Goulding, R.H.; Hoffman, D.J.; Saoutic, B.; Becoulet, A.; Fraboulet, D.; Beaumont, B.; Kuus, H.; Ladurelle, L.; Pascal, J.Y.

    1995-01-01

    A fast reciprocating ion cyclotron range of frequencies (ICRF) probe was installed and operated on TORE SUPRA during 1992/1993. The body of the probe was originally used on the ATF experiment at Oak Ridge National Laboratory. The probe was adapted for use on TORE SUPRA, and mounted on one of the two fast reciprocating probe mounts. The probe consists of two orthogonal single-turn wire loops, mounted so that one loop senses toroidal rf magnetic fields and the other senses poloidal rf magnetic fields. The probe began operation in June, 1993. The probe active area is approximately 5 cm long by 2 cm, and the reciprocating mount has a slow stroke (5 cm/s) of 30 cm and a fast stroke (1.5 m/s) of about 10 cm. The probe was operated at distances from the plasma edge ranging from 30 to -5 cm (i.e., inside the last closed flux surface). The probe design, electronics, calibration, data acquisition, and data processing are discussed. First data from the probe are presented as a function of ICRF power, distance from the plasma, loop orientation, and other plasma parameters. Initial data show parametric instabilities do not play an important role for ICRF in the TORE SUPRA edge and scrape-off-layer (SOL) plasmas. Additionally it is observed that the probe signal has little or no dependence on position in the SOL/plasma edge

  10. Primitive chain network simulations of probe rheology.

    Science.gov (United States)

    Masubuchi, Yuichi; Amamoto, Yoshifumi; Pandey, Ankita; Liu, Cheng-Yang

    2017-09-27

    Probe rheology experiments, in which the dynamics of a small amount of probe chains dissolved in immobile matrix chains is discussed, have been performed for the development of molecular theories for entangled polymer dynamics. Although probe chain dynamics in probe rheology is considered hypothetically as single chain dynamics in fixed tube-shaped confinement, it has not been fully elucidated. For instance, the end-to-end relaxation of probe chains is slower than that for monodisperse melts, unlike the conventional molecular theories. In this study, the viscoelastic and dielectric relaxations of probe chains were calculated by primitive chain network simulations. The simulations semi-quantitatively reproduced the dielectric relaxation, which reflects the effect of constraint release on the end-to-end relaxation. Fair agreement was also obtained for the viscoelastic relaxation time. However, the viscoelastic relaxation intensity was underestimated, possibly due to some flaws in the model for the inter-chain cross-correlations between probe and matrix chains.

  11. Aspheric surface measurement using capacitive probes

    Science.gov (United States)

    Tao, Xin; Yuan, Daocheng; Li, Shaobo

    2017-02-01

    With the application of aspheres in optical fields, high precision and high efficiency aspheric surface metrology becomes a hot research topic. We describe a novel method of non-contact measurement of aspheric surface with capacitive probe. Taking an eccentric spherical surface as the object of study, the averaging effect of capacitive probe measurement and the influence of tilting the capacitive probe on the measurement results are investigated. By comparing measurement results from simultaneous measurement of the capacitive probe and contact probe of roundness instrument, this paper indicates the feasibility of using capacitive probes to test aspheric surface and proposes the compensation method of measurement error caused by averaging effect and the tilting of the capacitive probe.

  12. Probing SH2-domains using Inhibitor Affinity Purification (IAP).

    Science.gov (United States)

    Höfener, Michael; Heinzlmeir, Stephanie; Kuster, Bernhard; Sewald, Norbert

    2014-01-01

    Many human diseases are correlated with the dysregulation of signal transduction processes. One of the most important protein interaction domains in the context of signal transduction is the Src homology 2 (SH2) domain that binds phosphotyrosine residues. Hence, appropriate methods for the investigation of SH2 proteins are indispensable in diagnostics and medicinal chemistry. Therefore, an affinity resin for the enrichment of all SH2 proteins in one experiment would be desirable. However, current methods are unable to address all SH2 proteins simultaneously with a single compound or a small array of compounds. In order to overcome these limitations for the investigation of this particular protein family in future experiments, a dipeptide-derived probe has been designed, synthesized and evaluated. This probe successfully enriched 22 SH2 proteins from mixed cell lysates which contained 50 SH2 proteins. Further characterization of the SH2 binding properties of the probe using depletion and competition experiments indicated its ability to enrich complexes consisting of SH2 domain bearing regulatory PI3K subunits and catalytic phosphoinositide 3-kinase (PI3K) subunits that have no SH2 domain. The results make this probe a promising starting point for the development of a mixed affinity resin with complete SH2 protein coverage. Moreover, the additional findings render it a valuable tool for the evaluation of PI3K complex interrupting inhibitors.

  13. Gamma-Ray Imaging Probes.

    Science.gov (United States)

    Wild, Walter James

    1988-12-01

    External nuclear medicine diagnostic imaging of early primary and metastatic lung cancer tumors is difficult due to the poor sensitivity and resolution of existing gamma cameras. Nonimaging counting detectors used for internal tumor detection give ambiguous results because distant background variations are difficult to discriminate from neighboring tumor sites. This suggests that an internal imaging nuclear medicine probe, particularly an esophageal probe, may be advantageously used to detect small tumors because of the ability to discriminate against background variations and the capability to get close to sites neighboring the esophagus. The design, theory of operation, preliminary bench tests, characterization of noise behavior and optimization of such an imaging probe is the central theme of this work. The central concept lies in the representation of the aperture shell by a sequence of binary digits. This, coupled with the mode of operation which is data encoding within an axial slice of space, leads to the fundamental imaging equation in which the coding operation is conveniently described by a circulant matrix operator. The coding/decoding process is a classic coded-aperture problem, and various estimators to achieve decoding are discussed. Some estimators require a priori information about the object (or object class) being imaged; the only unbiased estimator that does not impose this requirement is the simple inverse-matrix operator. The effects of noise on the estimate (or reconstruction) is discussed for general noise models and various codes/decoding operators. The choice of an optimal aperture for detector count times of clinical relevance is examined using a statistical class-separability formalism.

  14. Active Probing of Space Plasmas

    Science.gov (United States)

    1989-09-01

    ft. shuttle wake mlay also a kect the optration (if mi’:nc di.tg. Ibk Prwwattr of ,frttirw 844 I. %rvaom ’itbi h" $od iy radlet 6�va of IkeA dtm t...probe had a specially designed inner shaft caused by the existence of some ballistic electrons after made with .pring sleel tubing. By externally...potential to the electron thermal energy i(s distances downstream of the body (see Fig. 1). This (e OIT,) was on the order of 10 in steady state. design

  15. Astrophysical probes of fundamental physics

    International Nuclear Information System (INIS)

    Martins, C.J.A.P.

    2009-01-01

    I review the motivation for varying fundamental couplings and discuss how these measurements can be used to constrain fundamental physics scenarios that would otherwise be inaccessible to experiment. I highlight the current controversial evidence for varying couplings and present some new results. Finally I focus on the relation between varying couplings and dark energy, and explain how varying coupling measurements might be used to probe the nature of dark energy, with some advantages over standard methods. In particular I discuss what can be achieved with future spectrographs such as ESPRESSO and CODEX.

  16. Astrophysical probes of fundamental physics

    Energy Technology Data Exchange (ETDEWEB)

    Martins, C.J.A.P. [Centro de Astrofisica, Universidade do Porto, Rua das Estrelas, 4150-762 Porto (Portugal); DAMTP, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA (United Kingdom)

    2009-10-15

    I review the motivation for varying fundamental couplings and discuss how these measurements can be used to constrain fundamental physics scenarios that would otherwise be inaccessible to experiment. I highlight the current controversial evidence for varying couplings and present some new results. Finally I focus on the relation between varying couplings and dark energy, and explain how varying coupling measurements might be used to probe the nature of dark energy, with some advantages over standard methods. In particular I discuss what can be achieved with future spectrographs such as ESPRESSO and CODEX.

  17. A micromachined membrane-based active probe for biomolecular mechanics measurement

    Science.gov (United States)

    Torun, H.; Sutanto, J.; Sarangapani, K. K.; Joseph, P.; Degertekin, F. L.; Zhu, C.

    2007-04-01

    A novel micromachined, membrane-based probe has been developed and fabricated as assays to enable parallel measurements. Each probe in the array can be individually actuated, and the membrane displacement can be measured with high resolution using an integrated diffraction-based optical interferometer. To illustrate its application in single-molecule mechanics experiments, this membrane probe was used to measure unbinding forces between L-selectin reconstituted in a polymer-cushioned lipid bilayer on the probe membrane and an antibody adsorbed on an atomic force microscope cantilever. Piconewton range forces between single pairs of interacting molecules were measured from the cantilever bending while using the membrane probe as an actuator. The integrated diffraction-based optical interferometer of the probe was demonstrated to have floor for frequencies as low as 3 Hz with a differential readout scheme. With soft probe membranes, this low noise level would be suitable for direct force measurements without the need for a cantilever. Furthermore, the probe membranes were shown to have 0.5 µm actuation range with a flat response up to 100 kHz, enabling measurements at fast speeds.

  18. Data Mining Empowers the Generation of a Novel Class of Chromosome-specific DNA Probes

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Hui; Weier, Heinz-Ulrich G.; Kwan, Johnson; Wang, Mei; O' Brien, Benjamin

    2011-03-08

    Probes that allow accurate delineation of chromosome-specific DNA sequences in interphase or metaphase cell nuclei have become important clinical tools that deliver life-saving information about the gender or chromosomal make-up of a product of conception or the probability of an embryo to implant, as well as the definition of tumor-specific genetic signatures. Often such highly specific DNA probes are proprietary in nature and have been the result of extensive probe selection and optimization procedures. We describe a novel approach that eliminates costly and time consuming probe selection and testing by applying data mining and common bioinformatics tools. Similar to a rational drug design process in which drug-protein interactions are modeled in the computer, the rational probe design described here uses a set of criteria and publicly available bioinformatics software to select the desired probe molecules from libraries comprised of hundreds of thousands of probe molecules. Examples describe the selection of DNA probes for the human X and Y chromosomes, both with unprecedented performance, but in a similar fashion, this approach can be applied to other chromosomes or species.

  19. Laser-heated emissive plasma probe.

    Science.gov (United States)

    Schrittwieser, Roman; Ionita, Codrina; Balan, Petru; Gstrein, Ramona; Grulke, Olaf; Windisch, Thomas; Brandt, Christian; Klinger, Thomas; Madani, Ramin; Amarandei, George; Sarma, Arun K

    2008-08-01

    Emissive probes are standard tools in laboratory plasmas for the direct determination of the plasma potential. Usually they consist of a loop of refractory wire heated by an electric current until sufficient electron emission. Recently emissive probes were used also for measuring the radial fluctuation-induced particle flux and other essential parameters of edge turbulence in magnetized toroidal hot plasmas [R. Schrittwieser et al., Plasma Phys. Controlled Fusion 50, 055004 (2008)]. We have developed and investigated various types of emissive probes, which were heated by a focused infrared laser beam. Such a probe has several advantages: higher probe temperature without evaporation or melting and thus higher emissivity and longer lifetime, no deformation of the probe in a magnetic field, no potential drop along the probe wire, and faster time response. The probes are heated by an infrared diode laser with 808 nm wavelength and an output power up to 50 W. One probe was mounted together with the lens system on a radially movable probe shaft, and radial profiles of the plasma potential and of its oscillations were measured in a linear helicon discharge.

  20. Laser-heated emissive plasma probe

    International Nuclear Information System (INIS)

    Schrittwieser, Roman; Ionita, Codrina; Balan, Petru; Gstrein, Ramona; Grulke, Olaf; Windisch, Thomas; Brandt, Christian; Klinger, Thomas; Madani, Ramin; Amarandei, George; Sarma, Arun K.

    2008-01-01

    Emissive probes are standard tools in laboratory plasmas for the direct determination of the plasma potential. Usually they consist of a loop of refractory wire heated by an electric current until sufficient electron emission. Recently emissive probes were used also for measuring the radial fluctuation-induced particle flux and other essential parameters of edge turbulence in magnetized toroidal hot plasmas [R. Schrittwieser et al., Plasma Phys. Controlled Fusion 50, 055004 (2008)]. We have developed and investigated various types of emissive probes, which were heated by a focused infrared laser beam. Such a probe has several advantages: higher probe temperature without evaporation or melting and thus higher emissivity and longer lifetime, no deformation of the probe in a magnetic field, no potential drop along the probe wire, and faster time response. The probes are heated by an infrared diode laser with 808 nm wavelength and an output power up to 50 W. One probe was mounted together with the lens system on a radially movable probe shaft, and radial profiles of the plasma potential and of its oscillations were measured in a linear helicon discharge

  1. Laser-heated emissive plasma probe

    Science.gov (United States)

    Schrittwieser, Roman; Ionita, Codrina; Balan, Petru; Gstrein, Ramona; Grulke, Olaf; Windisch, Thomas; Brandt, Christian; Klinger, Thomas; Madani, Ramin; Amarandei, George; Sarma, Arun K.

    2008-08-01

    Emissive probes are standard tools in laboratory plasmas for the direct determination of the plasma potential. Usually they consist of a loop of refractory wire heated by an electric current until sufficient electron emission. Recently emissive probes were used also for measuring the radial fluctuation-induced particle flux and other essential parameters of edge turbulence in magnetized toroidal hot plasmas [R. Schrittwieser et al., Plasma Phys. Controlled Fusion 50, 055004 (2008)]. We have developed and investigated various types of emissive probes, which were heated by a focused infrared laser beam. Such a probe has several advantages: higher probe temperature without evaporation or melting and thus higher emissivity and longer lifetime, no deformation of the probe in a magnetic field, no potential drop along the probe wire, and faster time response. The probes are heated by an infrared diode laser with 808nm wavelength and an output power up to 50W. One probe was mounted together with the lens system on a radially movable probe shaft, and radial profiles of the plasma potential and of its oscillations were measured in a linear helicon discharge.

  2. PEGylated Red-Emitting Calcium Probe with Improved Sensing Properties for Neuroscience.

    Science.gov (United States)

    Ponsot, Flavien; Shen, Weida; Ashokkumar, Pichandi; Audinat, Etienne; Klymchenko, Andrey S; Collot, Mayeul

    2017-11-22

    Monitoring calcium concentration in the cytosol is of main importance as this ion drives many biological cascades within the cell. To this end, molecular calcium probes are widely used. Most of them, especially the red emitting probes, suffer from nonspecific interactions with inner membranes due to the hydrophobic nature of their fluorophore. To circumvent this issue, calcium probes conjugated to dextran can be used to enhance the hydrophilicity and reduce the nonspecific interaction and compartmentalization. However, dextran conjugates also feature important drawbacks including lower affinity, lower dynamic range, and slow diffusion. Herein, we combined the advantage of molecular probes and dextran conjugate without their drawbacks by designing a new red emitting turn-on calcium probe based on PET quenching, Rhod-PEG, in which the rhodamine fluorophore bears four PEG 4 units. This modification led to a high affinity calcium probe (K d = 748 nM) with reduced nonspecific interactions, enhanced photostability, two-photon absorbance, and brightness compared to the commercially available Rhod-2. After spectral characterizations, we showed that Rhod-PEG quickly and efficiently diffused through the dendrites of pyramidal neurons with an enhanced sensitivity (ΔF/F 0 ) at shorter time after patching compared to Rhod-2.

  3. Interfacing click chemistry with automated oligonucleotide synthesis for the preparation of fluorescent DNA probes containing internal xanthene and cyanine dyes

    DEFF Research Database (Denmark)

    Astakhova, I Kira; Wengel, Jesper

    2013-01-01

    Double-labeled oligonucleotide probes containing fluorophores interacting by energy-transfer mechanisms are essential for modern bioanalysis, molecular diagnostics, and in vivo imaging techniques. Although bright xanthene and cyanine dyes are gaining increased prominence within these fields, little...

  4. Portal monitor incorporating smart probes

    International Nuclear Information System (INIS)

    Bartos, D.; Constantin, F.; Guta, T.

    2003-01-01

    Portal monitors are intended for detection of radioactive and special nuclear materials in vehicles, pedestrians, luggage, as well as for prevention of illegal traffic of radioactive sources. Monitors provide audio and visual alarms when radioactive and/or special nuclear materials are detected. They can be recommended to officers of customs, border guard and emergency services, civil defense, fire brigades, police and military departments or nuclear research or energetic facilities. The portal monitor developed by us consists in a portal frame, which sustains five intelligent probes having long plastic scintillator (0.5 liters each). The probes communicate, by serial transmission, with a Central Unit constructed on the basis of the 80552 microcontroller. This one manages the handshake, calculates the background, establishes the measuring time, starts and stops each measurement and makes all the other decisions. Sound signals and an infrared sensor monitor the passing through the portal and the measuring procedure. For each measurement the result is displayed on a LCD device contaminated/uncontaminated; for the contaminated case a loud and long sound signal is also issued. An RS 232 serial interface is provided in order to further developments or custom made devices. As a result, the portal monitor detects 1 μ Ci 137 Cs, spread all over a human body, in a 20 μR/h gamma background for a measuring time of 1.5 or 10 seconds giving a 99% confidence factor. (authors)

  5. Twin probes for space geodesy

    International Nuclear Information System (INIS)

    Bertotti, B.

    1978-01-01

    The twin probe method, proposed by Bertotti and Colombo (1972) to get rid of nongravitational forces in interplanetary space, can be applied to a near-Earth orbit to eliminate the atmospheric drag. Two equal pairs of probes, each pair consisting of two passive, small and dense spheres of equal surface and different masses, are flown on a circular orbit at an altitude of about 300 km. Each pair determines the motion of an ideal point which feels only the gravitational forces. They are separated by a distance d of (100/200) km and are tracked from a spacecraft or the Space Shuttle, flying at the same altitude. The relative motion of the two ideal points is reconstructed and yields a measurement of the fine structure of the Earth gravitational field, corresponding to a harmonic order l approximately a/d (a is the radius of the Earth). The tracking can be done by laser ranging to the four spheres, covered by corner reflectors; Doppler ranging is more convenient for higher values of l and can also be used. The accuracy in the compensation of the non-gravitational forces and in the measurements one needs for a given l are discussed in detail. (author)

  6. The Gravity Probe B Experiment

    Science.gov (United States)

    Kolodziejczak, Jeffrey

    2008-01-01

    This presentation briefly describes the Gravity Probe B (GP-B) Experiment which is designed to measure parts of Einstein's general theory of relativity by monitoring gyroscope orientation relative to a distant guide star. To measure the miniscule angles predicted by Einstein's theory, it was necessary to build near-perfect gyroscopes that were approximately 50 million times more precise than the best navigational gyroscopes. A telescope mounted along the central axis of the dewar and spacecraft provided the experiment's pointing reference to a guide star. The telescope's image divide precisely split the star's beam into x-axis and y-axis components whose brightness could be compared. GP-B's 650-gallon dewar, kept the science instrument inside the probe at a cryogenic temperature for 17.3 months and also provided the thruster propellant for precision attitude and translation control. Built around the dewar, the GP-B spacecraft was a total-integrated system, comprising both the space vehicle and payload, dedicated as a single entity to experimentally testing predictions of Einstein's theory.

  7. Influence of probe motion on laser probe temperature in circulating blood.

    Science.gov (United States)

    Hehrlein, C; Splinter, R; Littmann, L; Tuntelder, J R; Tatsis, G P; Svenson, R H

    1991-01-01

    The purpose of this study was to evaluate the effect of probe motion on laser probe temperature in various blood flow conditions. Laser probe temperatures were measured in an in vitro blood circulation model consisting of 3.2 nm-diameter plastic tubes. A 2.0 mm-diameter metal probe attached to a 300 microns optical quartz fiber was coupled to an argon laser. Continuous wave 4 watts and 8 watts of laser power were delivered to the fiber tip corresponding to a 6.7 +/- 0.5 and 13.2 +/- 0.7 watts power setting at the laser generator. The laser probe was either moved with constant velocity or kept stationary. A thermocouple inserted in the lateral portion of the probe was used to record probe temperatures. Probe temperature changes were found with the variation of laser power, probe velocity, blood flow, and duration of laser exposure. Probe motion significantly reduced probe temperatures. After 10 seconds of 4 watts laser power the probe temperature in stagnant blood decreased from 303 +/- 18 degrees C to 113 +/- 17 degrees C (63%) by moving the probe with a velocity of 5 cm/sec. Blood flow rates of 170 ml/min further decreased the probe temperature from 113 +/- 17 degrees C to 50 +/- 8 degrees C (56%). At 8 watts of laser power a probe temperature reduction from 591 +/- 25 degrees C to 534 +/- 36 degrees C (10%) due to 5 cm/sec probe velocity was noted. Probe temperatures were reduced to 130 +/- 30 degrees C (78%) under the combined influence of 5 cm/sec probe velocity and 170 ml/min blood flow.(ABSTRACT TRUNCATED AT 250 WORDS)

  8. Development of conductivity probe and temperature probe for in-situ measurements in hydrological studies

    International Nuclear Information System (INIS)

    Chandra, U.; Galindo, B.J.; Castagnet, A.C.G.

    1981-05-01

    A conductivity probe and a temperature probe have been developed for in-situ measurements in various hydrological field studies. The conductivity probe has platinum electrodes and is powered with two 12 volt batteries. The sensing element of the temperature probe consists of a resistor of high coefficient of temperature. Response of the conductivity probe is measured in a milliampere mater while the resistance of the thermistor is read by a digital meter. The values of conductivity and temperature are derived from respective calibration. The probes are prototype and their range of measurement can be improved depending upon the requirement of the field problem. (Author) [pt

  9. Multifrequency scanning probe microscopy study of nanodiamond agglomerates

    Science.gov (United States)

    Aravind, Vasudeva; Lippold, Stephen; Li, Qian; Strelcov, Evgheny; Okatan, Baris; Legum, Benjamin; Kalinin, Sergei; Clarion University Team; Oak Ridge National Laboratory Team

    Due to their rich surface chemistry and excellent mechanical properties and non-toxic nature, nanodiamond particles have found applications such as biomedicine, tribology and lubrication, targeted drug delivery systems, tissue scaffolds and surgical implants. Although single nanodiamond particles have diameters about 4-5nm, they tend to form agglomerates. While these agglomerates can be useful for some purposes, many applications of nanodiamonds require single particle, disaggregated nanodiamonds. This work is oriented towards studying forces and interactions that contribute to agglomeration in nanodiamonds. In this work, using multifrequency scanning probe microscopy techniques, we show that agglomerate sizes can vary between 50-100nm in raw nanodiamonds. Extremeties of particles and Interfaces between agglomerates show dissipative forces with scanning probe microscope tip, indicating agglomerates could act as points of increased adhesion, thus reducing lubricating efficiency when nanodiamonds are used as lubricant additives. This research was conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility.

  10. CMS results on electroweak probes from LHC Run 1

    CERN Document Server

    AUTHOR|(CDS)2081933

    2016-01-01

    Electroweak boson production is an important benchmark process in high-energy heavy-ion collisions at the LHC. The Z and W~bosons do not participate in the strong interaction and their leptonic decays provide medium-blind probes of the initial state of the collisions. Final results on Z~boson production in PbPb~collisions compared to pp~collisions are presented. The centrality dependence confirms the binary scaling of hard probes in heavy-ion collisions and the differential cross sections show that initial state effects are small compared to the statistical precision of the available data. Measurements of the W and Z~boson production in pPb collisions, combining both the muon and electron decay channels are also presented. The data are compared to theory predictions for nuclear modifications of the parton distributions and show a clear sensitivity to these effects.

  11. Internal magnetic probe data from ZT-40

    International Nuclear Information System (INIS)

    Burkhardt, L.C.; Phillips, J.A.

    1981-05-01

    Measurements of magnetic field distribution as a function of time and radius were made in ZT-40 with its ceramic vacuum vessel. Data were obtained with a 10-station, 20-coil magnetic probe, measuring the B/sub p/ and B/sub epsilon/ orthogonal field components in deuterium plasma discharges. Sheath formation and diffusion, magnetic axis location and motion, the effect of the probe on the plasma, and the consistency of flux measurements with external probes are examined

  12. Platinum(II) complexes as spectroscopic probes for biomolecules

    Energy Technology Data Exchange (ETDEWEB)

    Ratilla, E.

    1990-09-21

    The use of platinum(II) complexes as tags and probes for biomolecules is indeed advantageous for their reactivities can be selective for certain purposes through an interplay of mild reaction conditions and of the ligands bound to the platinum. The use of {sup 195}Pt NMR as a method of detecting platinum and its interactions with biomolecules was carried out with the simplest model of platinum(II) tagging to proteins. Variable-temperature {sup 195}Pt NMR spectroscopy proved useful in studying the stereodynamics of complex thioethers like methionine. The complex, Pt(trpy)Cl{sup +}, with its chromophore has a greater potential for probing proteins. It is a noninvasive and selective tag for histidine and cysteine residues on the surface of cytochrome c at pH 5. The protein derivatives obtained are separable, and the tags are easily quantitated and differentiated through the metal-to-ligand charge transfer bands which are sensitive to the environment of the tag. Increasing the pH to 7.0 led to the modification by Pt(trpy)Cl{sup +}of Arg 91 in cytochrome c. Further studies with guanidine-containing ligands as models for arginine modification by Pt(trpy)Cl{sup +} showed that guanidine can act as a terminal ligand and as a bridging ligand. Owing to the potential utility of Pt(trpy)L{sup n+} as electron dense probes of nucleic acid structure, interactions of this bis-Pt(trpy){sup 2+} complex with nucleic acids was evaluated. Indeed, the complex interacts non-covalently with nucleic acids. Its interactions with DNA are not exactly the same as those of its precedents. Most striking is its ability to form highly immobile bands of DNA upon gel electrophoresis. 232 refs.

  13. HYDROGEN VACANCY INTERACTION IN TUNGSTEN

    NARCIS (Netherlands)

    FRANSENS, [No Value; ELKERIEM, MSA; PLEITER, F

    1991-01-01

    Hydrogen-vacancy interaction in tungsten was investigated by means of the perturbed angular correlation technique, using the isotope In-111 as a probe. Hydrogen trapping at an In-111-vacancy cluster manifests itself as a change of the local electric field gradient, which gives rise to an observable

  14. HYDROGEN VACANCY INTERACTION IN MOLYBDENUM

    NARCIS (Netherlands)

    Abd El Keriem, M.S.; van der Werf, D.P.; Pleiter, F

    1993-01-01

    Vacancy-hydrogen interaction in molybdenum was investigated by means of the perturbed angular correlation technique, using the isotope In-111 as a probe. The complex InV2 turned out to trap up to two hydrogen atoms: trapping of a single hydrogen atom gives rise to a decrease of the quadrupole

  15. NeuroMEMS: Neural Probe Microtechnologies

    Directory of Open Access Journals (Sweden)

    Sam Musallam

    2008-10-01

    Full Text Available Neural probe technologies have already had a significant positive effect on our understanding of the brain by revealing the functioning of networks of biological neurons. Probes are implanted in different areas of the brain to record and/or stimulate specific sites in the brain. Neural probes are currently used in many clinical settings for diagnosis of brain diseases such as seizers, epilepsy, migraine, Alzheimer’s, and dementia. We find these devices assisting paralyzed patients by allowing them to operate computers or robots using their neural activity. In recent years, probe technologies were assisted by rapid advancements in microfabrication and microelectronic technologies and thus are enabling highly functional and robust neural probes which are opening new and exciting avenues in neural sciences and brain machine interfaces. With a wide variety of probes that have been designed, fabricated, and tested to date, this review aims to provide an overview of the advances and recent progress in the microfabrication techniques of neural probes. In addition, we aim to highlight the challenges faced in developing and implementing ultralong multi-site recording probes that are needed to monitor neural activity from deeper regions in the brain. Finally, we review techniques that can improve the biocompatibility of the neural probes to minimize the immune response and encourage neural growth around the electrodes for long term implantation studies.

  16. Outer planet probe cost estimates: First impressions

    Science.gov (United States)

    Niehoff, J.

    1974-01-01

    An examination was made of early estimates of outer planetary atmospheric probe cost by comparing the estimates with past planetary projects. Of particular interest is identification of project elements which are likely cost drivers for future probe missions. Data are divided into two parts: first, the description of a cost model developed by SAI for the Planetary Programs Office of NASA, and second, use of this model and its data base to evaluate estimates of probe costs. Several observations are offered in conclusion regarding the credibility of current estimates and specific areas of the outer planet probe concept most vulnerable to cost escalation.

  17. Intrauterine photoacoustic and ultrasound imaging probe

    Science.gov (United States)

    Miranda, Christopher; Barkley, Joel; Smith, Barbara S.

    2018-04-01

    Intrauterine photoacoustic and ultrasound imaging are probe-based imaging modalities with translational potential for use in detecting endometrial diseases. This deep-tissue imaging probe design allows for the retrofitting of commercially available endometrial sampling curettes. The imaging probe presented here has a 2.92-mm diameter and approximate length of 26 cm, which allows for entry into the human endometrial cavity, making it possible to use photoacoustic imaging and high-resolution ultrasound to characterize the uterus. We demonstrate the imaging probes' ability to provide structural information of an excised pig uterus using ultrasound imaging and detect photoacoustic signals at a radial depth of 1 cm.

  18. Test design requirements: Thermal conductivity probe testing

    International Nuclear Information System (INIS)

    Heath, R.E.

    1985-01-01

    This document establishes the test design requirements for development of a thermal conductivity probe test. The thermal conductivity probe determines in situ thermal conductivity using a line source transient heat conduction analysis. This document presents the rationale for thermal conductivity measurement using a thermal conductivity probe. A general test description is included. Support requirements along with design constraints are detailed to allow simple design of the thermal conductivity probe and test. The schedule and delivery requirements of the responsible test designer are also included. 7 refs., 1 fig

  19. Scanning microscopic four-point conductivity probes

    DEFF Research Database (Denmark)

    Petersen, Christian Leth; Hansen, Torben Mikael; Bøggild, Peter

    2002-01-01

    A method for fabricating microscopic four-point probes is presented. The method uses silicon-based microfabrication technology involving only two patterning steps. The last step in the fabrication process is an unmasked deposition of the conducting probe material, and it is thus possible to select...... the conducting material either for a silicon wafer or a single probe unit. Using shadow masking photolithography an electrode spacing (pitch) down to 1.1 mum was obtained, with cantilever separation down to 200 run. Characterisation measurements have shown the microscopic probes to be mechanically very flexible...

  20. Magnetic Barkhausen Noise Measurements Using Tetrapole Probe Designs

    Science.gov (United States)

    McNairnay, Paul

    A magnetic Barkhausen noise (MBN) testing system was developed for Defence Research and Development Canada (DRDC) to perform MBN measurements on the Royal Canadian Navy's Victoria class submarine hulls that can be correlated with material properties, including residual stress. The DRDC system was based on the design of a MBN system developed by Steven White at Queen's University, which was capable of performing rapid angular dependent measurements through the implementation of a flux controlled tetrapole probe. In tetrapole probe designs, the magnetic excitation field is rotated in the surface plane of the sample under the assumption of linear superposition of two orthogonal magnetic fields. During the course of this work, however, the validity of flux superposition in ferromagnetic materials, for the purpose of measuring MBN, was brought into question. Consequently, a study of MBN anisotropy using tetrapole probes was performed. Results indicate that MBN anisotropy measured under flux superposition does not simulate MBN anisotropy data obtained through manual rotation of a single dipole excitation field. It is inferred that MBN anisotropy data obtained with tetrapole probes is the result of the magnetic domain structure's response to an orthogonal magnetization condition and not necessarily to any bulk superposition magnetization in the sample. A qualitative model for the domain configuration under two orthogonal magnetic fields is proposed to describe the results. An empirically derived fitting equation, that describes tetrapole MBN anisotropy data, is presented. The equation describes results in terms of two largely independent orthogonal fields, and includes interaction terms arising due to competing orthogonally magnetized domain structures and interactions with the sample's magnetic easy axis. The equation is used to fit results obtained from a number of samples and tetrapole orientations and in each case correctly identifies the samples' magnetic easy axis.

  1. Fundamental Physics with Electroweak Probes of Nuclei

    Science.gov (United States)

    Pastore, Saori

    2018-02-01

    The past decade has witnessed tremendous progress in the theoretical and computational tools that produce our understanding of nuclei. A number of microscopic calculations of nuclear electroweak structure and reactions have successfully explained the available experimental data, yielding a complex picture of the way nuclei interact with electroweak probes. This achievement is of great interest from the pure nuclear-physics point of view. But it is of much broader interest too, because the level of accuracy and confidence reached by these calculations opens up the concrete possibility of using nuclei to address open questions in other sub-fields of physics, such as, understanding the fundamental properties of neutrinos, or the particle nature of dark matter. In this talk, I will review recent progress in microscopic calculations of electroweak properties of light nuclei, including electromagnetic moments, form factors and transitions in between lowlying nuclear states along with preliminary studies for single- and double-beta decay rates. I will illustrate the key dynamical features required to explain the available experimental data, and, if time permits, present a novel framework to calculate neutrino-nucleus cross sections for A > 12 nuclei.

  2. Probing noncommutative theories with quantum optical experiments

    Directory of Open Access Journals (Sweden)

    Sanjib Dey

    2017-11-01

    Full Text Available One of the major difficulties of modern science underlies at the unification of general relativity and quantum mechanics. Different approaches towards such theory have been proposed. Noncommutative theories serve as the root of almost all such approaches. However, the identification of the appropriate passage to quantum gravity is suffering from the inadequacy of experimental techniques. It is beyond our ability to test the effects of quantum gravity thorough the available scattering experiments, as it is unattainable to probe such high energy scale at which the effects of quantum gravity appear. Here we propose an elegant alternative scheme to test such theories by detecting the deformations emerging from the noncommutative structures. Our protocol relies on the novelty of an opto-mechanical experimental setup where the information of the noncommutative oscillator is exchanged via the interaction with an optical pulse inside an optical cavity. We also demonstrate that our proposal is within the reach of current technology and, thus, it could uncover a feasible route towards the realization of quantum gravitational phenomena thorough a simple table-top experiment.

  3. Millimeter-wave active probe

    Science.gov (United States)

    Majidi-Ahy, Gholamreza; Bloom, David M.

    1991-01-01

    A millimeter-wave active probe for use in injecting signals with frequencies above 50GHz to millimeter-wave and ultrafast devices and integrated circuits including a substrate upon which a frequency multiplier consisting of filter sections and impedance matching sections are fabricated in uniplanar transmission line format. A coaxial input and uniplanar 50 ohm transmission line couple an approximately 20 GHz input signal to a low pass filter which rolls off at approximately 25 GHz. An input impedance matching section couples the energy from the low pass filter to a pair of matched, antiparallel beam lead diodes. These diodes generate odd-numberd harmonics which are coupled out of the diodes by an output impedance matching network and bandpass filter which suppresses the fundamental and third harmonics and selects the fifth harmonic for presentation at an output.

  4. Nuclear reactions as structure probes

    International Nuclear Information System (INIS)

    Fernandez, Bernard; Cugnon, Joseph; Roussel-Chomaz, Patricia; Sparenberg, Jean-Marc; Oliveira Santos, Francois de; Bauge, Eric; Poves, Alfredo; Keeley, Nicholas; Simenel, Cedric; Avez, Benoit; Lacroix, Denis; Baye, Daniel; Cortina-Gil, Dolores; Pons, Alexandre

    2007-09-01

    This publication gathers courses which aim at giving a view on new experiments which are performed by using radioactive beams, notably low intensity beams, in different accelerators, and allow the structure of very exotic nuclei to be characterized. Experimental as well as theoretical aspects are thus addressed. The contributions propose: a brief history of nuclear reactions and of instruments used to study them from the discovery of nucleus to the DWBA (Distorted Wave Born Approximation); an overview of nuclear reactions; experimental techniques; the theory of collisions at low energy; resonant elastic scattering, inelastic scattering and astrophysical reactions; to probe nuclear structure with nucleons; shell model and spectroscopic factors; analysis of transfer reactions and determination of spectroscopic factors; microscopic approaches of nuclear dynamics; theoretical aspects of dissociation reactions; experimental aspects of knockout reactions; research in oenology with the chemical characterisation of defective ageing of dry white wines

  5. Gravity Probe B orbit determination

    International Nuclear Information System (INIS)

    Shestople, P; Ndili, A; Parkinson, B W; Small, H; Hanuschak, G

    2015-01-01

    The Gravity Probe B (GP-B) satellite was equipped with a pair of redundant Global Positioning System (GPS) receivers used to provide navigation solutions for real-time and post-processed orbit determination (OD), as well as to establish the relation between vehicle time and coordinated universal time. The receivers performed better than the real-time position requirement of 100 m rms per axis. Post-processed solutions indicated an rms position error of 2.5 m and an rms velocity error of 2.2 mm s −1 . Satellite laser ranging measurements provided independent verification of the GPS-derived GP-B orbit. We discuss the modifications and performance of the Trimble Advance Navigation System Vector III GPS receivers. We describe the GP-B precision orbit and detail the OD methodology, including ephemeris errors and the laser ranging measurements. (paper)

  6. Supersymmetric probes on the conifold

    International Nuclear Information System (INIS)

    Arean, Daniel; Crooks, David E.; Ramallo, Alfonso V.

    2004-01-01

    We study the supersymmetric embeddings of different D-brane probes in the AdS 5 xT 1,1 geometry. The main tool employed is kappa symmetry and the cases studied include D3-, D5- and D7-branes. We find a family of three-cycles of the T 1,1 space over which a D3-brane can be wrapped supersymmetrically and we determine the field content of the corresponding gauge theory duals. Supersymmetric configurations of D5-branes wrapping a two-cycle and of spacetime filling D7-branes are also found. The configurations in which the entire T 1,1 space is wrapped by a D5-brane (baryon vertex) and a D7-brane are also studied. Some other embeddings which break supersymmetry but are nevertheless stable are also determined. (author)

  7. Plutonium helps probe protein, superconductor

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    Scientists are finding that plutonium can be a useful research tool that may help them answer important questions in fields as diverse as biochemistry and solid-state physics. This paper reports that U.S. research involving plutonium is confined to the Department of Energy's national laboratories and centers around nuclear weapons technology, waste cleanup and disposal, and health effects. But at Los Alamos National Laboratory, scientists also are using plutonium to probe the biochemical behavior of calmodulin, a key calcium-binding protein that mediates calcium-regulated processes in biological systems. At Argonne National Laboratory, another team is trying to learn how a superconductor's properties are affected by the 5f electrons of an actinide like plutonium

  8. Gravity Probe B spacecraft description

    International Nuclear Information System (INIS)

    Bennett, Norman R; Burns, Kevin; Katz, Russell; Kirschenbaum, Jon; Mason, Gary; Shehata, Shawky

    2015-01-01

    The Gravity Probe B spacecraft, developed, integrated, and tested by Lockheed Missiles and Space Company and later Lockheed Martin Corporation, consisted of structures, mechanisms, command and data handling, attitude and translation control, electrical power, thermal control, flight software, and communications. When integrated with the payload elements, the integrated system became the space vehicle. Key requirements shaping the design of the spacecraft were: (1) the tight mission timeline (17 months, 9 days of on-orbit operation), (2) precise attitude and translational control, (3) thermal protection of science hardware, (4) minimizing aerodynamic, magnetic, and eddy current effects, and (5) the need to provide a robust, low risk spacecraft. The spacecraft met all mission requirements, as demonstrated by dewar lifetime meeting specification, positive power and thermal margins, precision attitude control and drag-free performance, reliable communications, and the collection of more than 97% of the available science data. (paper)

  9. Scanning probe microscopy competency development

    Energy Technology Data Exchange (ETDEWEB)

    Hawley, M.E.; Reagor, D.W.; Jia, Quan Xi [and others

    1998-12-31

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The project collaborators developed an ultra-high vacuum scanning tunneling microscope (UHV-STM) capability, integrated it with existing scanning probe microscopes, and developed new, advanced air-based scanning force techniques (SPMs). Programmatic, basic, and industrially related laboratory research requires the existence of SPMs, as well as expertise capable of providing local nano-scale information. The UHV-STM capability, equipped with load-lock system and several surface science techniques, will allow introduction, examination, and reaction of surfaces prepared under well-controlled vacuum conditions, including the examination of morphology and local bonding associated with the initial stages of film growth under controlled growth conditions. The resulting capabilities will enable the authors to respond to a variety of problems requiring local characterization of conducting and nonconducting surfaces in liquids, air, and UHV.

  10. Angular distributions as lifetime probes

    Energy Technology Data Exchange (ETDEWEB)

    Dror, Jeff Asaf; Grossman, Yuval [Department of Physics, LEPP, Cornell University,Ithaca, NY 14853 (United States)

    2014-06-27

    If new TeV scale particles are discovered, it will be important to determine their width. There is, however, a problematic region, where the width is too small to be determined directly, and too large to generate a secondary vertex. For a collection of colored, spin polarized particles, hadronization depolarizes the particles prior to their decay. The amount of depolarization can be used to probe the lifetime in the problematic region. In this paper we apply this method to a realistic scenario of a top-like particle that can be produced at the LHC. We study how depolarization affects the angular distributions of the decay products and derive an equation for the distributions that is sensitive to the lifetime.

  11. The Oxford Probe: an open access five-hole probe for aerodynamic measurements

    Science.gov (United States)

    Hall, B. F.; Povey, T.

    2017-03-01

    The Oxford Probe is an open access five-hole probe designed for experimental aerodynamic measurements. The open access probe can be manufactured by the end user via additive manufacturing (metal or plastic). The probe geometry, drawings, calibration maps, and software are available under a creative commons license. The purpose is to widen access to aerodynamic measurement techniques in education and research environments. There are many situations in which the open access probe will allow results of comparable accuracy to a well-calibrated commercial probe. We discuss the applications and limitations of the probe, and compare the calibration maps for 16 probes manufactured in different materials and at different scales, but with the same geometrical design.

  12. The Oxford Probe: an open access five-hole probe for aerodynamic measurements

    International Nuclear Information System (INIS)

    Hall, B F; Povey, T

    2017-01-01

    The Oxford Probe is an open access five-hole probe designed for experimental aerodynamic measurements. The open access probe can be manufactured by the end user via additive manufacturing (metal or plastic). The probe geometry, drawings, calibration maps, and software are available under a creative commons license. The purpose is to widen access to aerodynamic measurement techniques in education and research environments. There are many situations in which the open access probe will allow results of comparable accuracy to a well-calibrated commercial probe. We discuss the applications and limitations of the probe, and compare the calibration maps for 16 probes manufactured in different materials and at different scales, but with the same geometrical design. (paper)

  13. Probing Positron Gravitation at HERA

    International Nuclear Information System (INIS)

    Gharibyan, Vahagn

    2015-07-01

    An equality of particle and antiparticle gravitational interactions holds in general relativity and is supported by indirect observations. Here I develop a method based on high energy Compton scattering to measure the gravitational interaction of accelerated charged particles. Within that formalism the Compton spectra measured at HERA rule out the positron's anti-gravity and hint for a positron's 1.3(0.2)% weaker coupling to the gravitational field relative to an electron.

  14. Probing Positron Gravitation at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Gharibyan, Vahagn

    2015-07-15

    An equality of particle and antiparticle gravitational interactions holds in general relativity and is supported by indirect observations. Here I develop a method based on high energy Compton scattering to measure the gravitational interaction of accelerated charged particles. Within that formalism the Compton spectra measured at HERA rule out the positron's anti-gravity and hint for a positron's 1.3(0.2)% weaker coupling to the gravitational field relative to an electron.

  15. A sensitive fluorescent probe for the polar solvation dynamics at protein-surfactant interfaces.

    Science.gov (United States)

    Singh, Priya; Choudhury, Susobhan; Singha, Subhankar; Jun, Yongwoong; Chakraborty, Sandipan; Sengupta, Jhimli; Das, Ranjan; Ahn, Kyo-Han; Pal, Samir Kumar

    2017-05-17

    Relaxation dynamics at the surface of biologically important macromolecules is important taking into account their functionality in molecular recognition. Over the years it has been shown that the solvation dynamics of a fluorescent probe at biomolecular surfaces and interfaces account for the relaxation dynamics of polar residues and associated water molecules. However, the sensitivity of the dynamics depends largely on the localization and exposure of the probe. For noncovalent fluorescent probes, localization at the region of interest in addition to surface exposure is an added challenge compared to the covalently attached probes at the biological interfaces. Here we have used a synthesized donor-acceptor type dipolar fluorophore, 6-acetyl-(2-((4-hydroxycyclohexyl)(methyl)amino)naphthalene) (ACYMAN), for the investigation of the solvation dynamics of a model protein-surfactant interface. A significant structural rearrangement of a model histone protein (H1) upon interaction with anionic surfactant sodium dodecyl sulphate (SDS) as revealed from the circular dichroism (CD) studies is nicely corroborated in the solvation dynamics of the probe at the interface. The polarization gated fluorescence anisotropy of the probe compared to that at the SDS micellar surface clearly reveals the localization of the probe at the protein-surfactant interface. We have also compared the sensitivity of ACYMAN with other solvation probes including coumarin 500 (C500) and 4-(dicyanomethylene)-2-methyl-6-(p-dimethylamino-styryl)-4H-pyran (DCM). In comparison to ACYMAN, both C500 and DCM fail to probe the interfacial solvation dynamics of a model protein-surfactant interface. While C500 is found to be delocalized from the protein-surfactant interface, DCM becomes destabilized upon the formation of the interface (protein-surfactant complex). The timescales obtained from this novel probe have also been compared with other femtosecond resolved studies and molecular dynamics simulations.

  16. The TORE SUPRA fast reciprocating RF probe

    International Nuclear Information System (INIS)

    Thomas, C.E. Jr.; Harris, J.H.; Haste, G.R.

    1994-01-01

    A fast reciprocating ICRF (Ion Cyclotron Range of Frequencies) probe was installed and operated on TORE SUPRA during 1992/1993. The body of the probe was originally used on the ATF experiment at ORNL. The probe was adapted for use on TORE SUPRA, and mounted on one of the two fast reciprocating probe mounts. The probe consists of two orthogonal single-turn wire loops, mounted so that one loop senses toroidal RF magnetic fields and the other senses poloidal RF magnetic fields. The probe began operation in June, 1993. The probe active area is approximately 5 cm long by 2 cm, and the reciprocating mount has a slow stroke (5 cm/sec) of 30 cm by 2 cm, and the reciprocating mount has a slow stroke (5 cm/sec) of 30 cm and a fast stroke (1.5 m/sec) of about 10 cm. The probe was operated at distances from the plasma edge ranging from 30 cm to -5 cm (i.e., inside the last closed flux surface). The probe design, electronics, calibration, data acquisition and data processing are discussed. First data from the probe are presented as a function of ICRF power, distance from the plasma, loop orientation, and other plasma parameters. Initial data shows parametric instabilities do not play an important role for ICRF in the TORE SUPRA edge and scrape-off-layer (SOL) plasmas. Additionally it is observed that the probe signal has little or no dependence on position in the SOL/plasma edge

  17. A probe for Eddy current inspection devices

    International Nuclear Information System (INIS)

    1974-01-01

    The invention relates to a surface probe for Eddy current inspection devices. According to the invention, said probe comprises two magnetic core windings, with their axes in parallel relationship and at right angles to the surface of the part to be inspected. This can be applied to the nondestructive inspection of reactor components [fr

  18. Quality of the neutron probe calibration curve

    International Nuclear Information System (INIS)

    Libardi, Paulo Leonel; Moraes, Sergio Oliveira

    1997-01-01

    An experiment of neutron probe calibration has been performed, involving various volume size samples and collected at various distances from the access tubes. The experiment aimed to give some answers to questions such as suitable sample physical volume, always use of the same volume and sample distance from the neutron probe access tube

  19. Automatic kelvin probe compatible with ultrahigh vacuum

    NARCIS (Netherlands)

    Baikie, I.D.; van der Werf, Kees; Oerbekke, H.; Broeze, J.; van Silfhout, Arend

    1989-01-01

    This article describes a new type of in situ ultrahigh‐vacuum compatible kelvin probe based on a voice‐coil driving mechanism. This design exhibits several advantages over conventional mechanical feed‐through and (in situ) piezoelectric devices in regard to the possibility of multiple probe

  20. Surface charge measurement using an electrostatic probe

    DEFF Research Database (Denmark)

    Crichton, George C; McAllister, Iain Wilson

    1998-01-01

    During the 1960s, the first measurements of charge on dielectric surfaces using simple electrostatic probes were reported. However it is only within the last 10 years that a proper understanding of the probe response has been developed. This situation arose as a consequence of the earlier studies...

  1. NASA SMART Probe: Breast Cancer Application

    Science.gov (United States)

    Mah, Robert W.; Norvig, Peter (Technical Monitor)

    2000-01-01

    There is evidence in breast cancer and other malignancies that the physiologic environment within a tumor correlates with clinical outcome. We are developing a unique percutaneous Smart Probe to be used at the time of needle biopsy of the breast. The Smart Probe will simultaneously measure multiple physiologic parameters within a breast tumor. Direct and indirect measurements of tissue oxygen levels, blood flow, pH, and tissue fluid pressure will be analyzed in real-time. These parameters will be interpreted individually and collectively by innovative neural network techniques using advanced intelligent software. The goals are 1) develop a pecutaneous Smart Probe with multiple sensor modalities and applying advanced Information Technologies to provide real time diagnostic information of the tissue at tip of the probe, 2) test the percutaneous Smart Probe in women with benign and malignant breast masses who will be undergoing surgical biopsy, 3) correlate probe sensor data with benign and malignant status of breast masses, 4) determine whether the probe can detect physiologic differences within a breast tumor, and its margins, and in adjacent normal breast tissue, 5) correlate probe sensor data with known prognostic factors for breast caner, including tumor size, tumor grade, axillary lymph node metastases, estrogen receptor and progesterone receptor status.

  2. Inspecting Friction Stir Welding using Electromagnetic Probes

    Science.gov (United States)

    Kinchen, David G.

    2004-01-01

    A report describes the use of advanced electromagnetic probes to measure the dimensions, the spatial distribution of electrical conductivity, and related other properties of friction stir welds (FSWs) between parts made of the same or different aluminum alloy(s). The probes are of the type described in in another Tech Brief. To recapitulate: A probe of this type is essentially an eddy-current probe that includes a primary (driver) winding that meanders and multiple secondary (sensing) windings that meander along the primary winding. Electrical conductivity is commonly used as a measure of heat treatment and tempering of aluminum alloys, but prior to the development of these probes, the inadequate sensitivity and limited accuracy of electrical-conductivity probes precluded such use on FSWs between different aluminum alloys, and the resolution of those probes was inadequate for measurement of FSW dimensions with positions and metallurgical properties. In contrast, the present probes afford adequate accuracy and spatial resolution for the purposes of measuring the dimensions of FSW welds and correlating spatially varying electrical conductivities with metallurgical properties, including surface defects.

  3. Simultaneous surface and depth neural activity recording with graphene transistor-based dual-modality probes.

    Science.gov (United States)

    Du, Mingde; Xu, Xianchen; Yang, Long; Guo, Yichuan; Guan, Shouliang; Shi, Jidong; Wang, Jinfen; Fang, Ying

    2018-05-15

    Subdural surface and penetrating depth probes are widely applied to record neural activities from the cortical surface and intracortical locations of the brain, respectively. Simultaneous surface and depth neural activity recording is essential to understand the linkage between the two modalities. Here, we develop flexible dual-modality neural probes based on graphene transistors. The neural probes exhibit stable electrical performance even under 90° bending because of the excellent mechanical properties of graphene, and thus allow multi-site recording from the subdural surface of rat cortex. In addition, finite element analysis was carried out to investigate the mechanical interactions between probe and cortex tissue during intracortical implantation. Based on the simulation results, a sharp tip angle of π/6 was chosen to facilitate tissue penetration of the neural probes. Accordingly, the graphene transistor-based dual-modality neural probes have been successfully applied for simultaneous surface and depth recording of epileptiform activity of rat brain in vivo. Our results show that graphene transistor-based dual-modality neural probes can serve as a facile and versatile tool to study tempo-spatial patterns of neural activities. Copyright © 2018 Elsevier B.V. All rights reserved.

  4. Self-probing spectroscopy of XUV photo-ionization dynamics in atoms subjected to a strong-field environment.

    Science.gov (United States)

    Azoury, Doron; Krüger, Michael; Orenstein, Gal; Larsson, Henrik R; Bauch, Sebastian; Bruner, Barry D; Dudovich, Nirit

    2017-11-13

    Single-photon ionization is one of the most fundamental light matter interactions in nature, serving as a universal probe of the quantum state of matter. By probing the emitted electron, one can decode the full dynamics of the interaction. When photo-ionization is evolving in the presence of a strong laser field, the fundamental properties of the mechanism can be signicantly altered. Here we demonstrate how the liberated electron can perform a self-probing measurement of such interaction with attosecond precision. Extreme ultraviolet attosecond pulses initiate an electron wavepacket by photo-ionization, a strong infrared field controls its motion, and finally electron-ion collision maps it into re-emission of attosecond radiation bursts. Our measurements resolve the internal clock provided by the self-probing mechanism, obtaining a direct insight into the build-up of photo-ionization in the presence of the strong laser field.

  5. Hall probe magnetometer for SSC magnet cables

    International Nuclear Information System (INIS)

    Cross, R.W.; Goldfarb, R.B.

    1991-01-01

    The authors of this paper constructed a Hall probe magnetometer to measure the magnetization hysteresis loops of Superconducting Super Collider magnet cables. The instrument uses two Hall-effect field sensors to measure the applied field H and the magnetic induction B. Magnetization M is calculated from the difference of the two quantities. The Hall probes are centered coaxially in the bore of a superconducting solenoid with the B probe against the sample's broad surface. An alternative probe arrangement, in which M is measured directly, aligns the sample probe parallel to the field. The authors measured M as a function of H and field cycle rate both with and without a dc transport current. Flux creep as a function of current was measured from the dependence of ac loss on the cycling rate and from the decay of magnetization with time. Transport currents up to 20% of the critical current have minimal effect on magnetization and flux creep

  6. Neutron-based portable drug probe

    International Nuclear Information System (INIS)

    Womble, P. C.; Vourvopoulos, G.; Ball Howard, J.; Paschal, J.

    1999-01-01

    Based on previous measurements, a probe prototype for contraband detection utilizing the neutron technique of Pulsed Fast-Thermal Neutron Analysis (PFTNA) is being constructed. The prototype weighs less than 45 kg and is composed of a probe (5 cm diameter), a power pack and a data acquisition and display system. The probe is designed to be inserted in confined spaces such as the boiler of a ship or a tanker truck filled with liquid. The probe provides information on a) the elemental content, and b) the density variations of the interrogated object. By measuring elemental content, the probe can differentiate between innocuous materials and drugs. Density variations can be found through fast neutron transmission. In all cases, hidden drugs are identified through the measurement of the elemental content of the object, and the comparison of expected and measured elemental ratios

  7. Molecular Imaging Probe Development using Microfluidics

    Science.gov (United States)

    Liu, Kan; Wang, Ming-Wei; Lin, Wei-Yu; Phung, Duy Linh; Girgis, Mark D.; Wu, Anna M.; Tomlinson, James S.; Shen, Clifton K.-F.

    2012-01-01

    In this manuscript, we review the latest advancement of microfluidics in molecular imaging probe development. Due to increasing needs for medical imaging, high demand for many types of molecular imaging probes will have to be met by exploiting novel chemistry/radiochemistry and engineering technologies to improve the production and development of suitable probes. The microfluidic-based probe synthesis is currently attracting a great deal of interest because of their potential to deliver many advantages over conventional systems. Numerous chemical reactions have been successfully performed in micro-reactors and the results convincingly demonstrate with great benefits to aid synthetic procedures, such as purer products, higher yields, shorter reaction times compared to the corresponding batch/macroscale reactions, and more benign reaction conditions. Several ‘proof-of-principle’ examples of molecular imaging probe syntheses using microfluidics, along with basics of device architecture and operation, and their potential limitations are discussed here. PMID:22977436

  8. CERN: Antiprotons probe the nuclear stratosphere

    International Nuclear Information System (INIS)

    Anon.

    1995-01-01

    The outer periphery of heavy stable nuclei is notoriously difficult to study experimentally. While the well understood electromagnetic interaction between electrons (or muons) and protons has given the nuclear charge (or proton) distribution with high precision for almost all stable nuclei, neutron distribution studies are much less precise. This is especially true for large nuclear distances, where the nuclear density is small. A few previous experiments probing the nuclear ''stratosphere'' suggested that far from the centre of the nucleus (of the order of 2 nuclear radii) this stratosphere may be composed predominantly of neutrons. At the end of the sixties the term ''neutron halo'' was introduced to describe this phenomenon, but experimental evidence was scarce or even controversial, and remained so for almost a quarter of a century. Recently, the Warsaw/Munich/Berlin collaboration working within the PS203 experiment at CERN's LEAR low energy antiproton ring, proposed a new method to study the nuclear periphery using stopped antiprotons. The halo now looks firmer. A 200 MeV/c beam of antiprotons was slowed down by interactions with atomic electrons. When antiproton kinetic energy drops well below 1 keV, the particles are captured in the outermost orbits of ''exotic atoms'', where the antiprotons take the place of the usual orbital electrons. With the lower orbits in this antiprotonic atom empty, the antiproton drops toward the nuclear surface, first emitting Auger electrons and later predominantly antiprotonic X-rays. Due to the strong interaction between antiprotons and nucleons, the antiproton succumbs to annihilation with a nucleon in the rarified nuclear stratosphere, far above the innermost Bohr orbit of the atom. The annihilation probability in heavy nuclei is maximal where the nuclear density is about 3% of its central value and extends to densities many orders of magnitude smaller

  9. CERN: Antiprotons probe the nuclear stratosphere

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1995-06-15

    The outer periphery of heavy stable nuclei is notoriously difficult to study experimentally. While the well understood electromagnetic interaction between electrons (or muons) and protons has given the nuclear charge (or proton) distribution with high precision for almost all stable nuclei, neutron distribution studies are much less precise. This is especially true for large nuclear distances, where the nuclear density is small. A few previous experiments probing the nuclear ''stratosphere'' suggested that far from the centre of the nucleus (of the order of 2 nuclear radii) this stratosphere may be composed predominantly of neutrons. At the end of the sixties the term ''neutron halo'' was introduced to describe this phenomenon, but experimental evidence was scarce or even controversial, and remained so for almost a quarter of a century. Recently, the Warsaw/Munich/Berlin collaboration working within the PS203 experiment at CERN's LEAR low energy antiproton ring, proposed a new method to study the nuclear periphery using stopped antiprotons. The halo now looks firmer. A 200 MeV/c beam of antiprotons was slowed down by interactions with atomic electrons. When antiproton kinetic energy drops well below 1 keV, the particles are captured in the outermost orbits of ''exotic atoms'', where the antiprotons take the place of the usual orbital electrons. With the lower orbits in this antiprotonic atom empty, the antiproton drops toward the nuclear surface, first emitting Auger electrons and later predominantly antiprotonic X-rays. Due to the strong interaction between antiprotons and nucleons, the antiproton succumbs to annihilation with a nucleon in the rarified nuclear stratosphere, far above the innermost Bohr orbit of the atom. The annihilation probability in heavy nuclei is maximal where the nuclear density is about 3% of its central value and extends to densities many orders of magnitude smaller. Antiproton annihilation on a proton or on a neutron at the nuclear

  10. The time resolved measurement of ultrashort terahertz-band electric fields without an ultrashort probe

    International Nuclear Information System (INIS)

    Walsh, D. A.; Snedden, E. W.; Jamison, S. P.

    2015-01-01

    The time-resolved detection of ultrashort pulsed THz-band electric field temporal profiles without an ultrashort laser probe is demonstrated. A non-linear interaction between a narrow-bandwidth optical probe and the THz pulse transposes the THz spectral intensity and phase information to the optical region, thereby generating an optical pulse whose temporal electric field envelope replicates the temporal profile of the real THz electric field. This optical envelope is characterised via an autocorrelation based FROG (frequency resolved optical gating) measurement, hence revealing the THz temporal profile. The combination of a narrow-bandwidth, long duration, optical probe, and self-referenced FROG makes the technique inherently immune to timing jitter between the optical probe and THz pulse and may find particular application where the THz field is not initially generated via ultrashort laser methods, such as the measurement of longitudinal electron bunch profiles in particle accelerators

  11. Weak interactions at high energies

    International Nuclear Information System (INIS)

    Ellis, J.

    1978-08-01

    Review lectures are presented on the phenomenological implications of the modern spontaneously broken gauge theories of the weak and electromagnetic interactions, and some observations are made about which high energy experiments probe what aspects of gauge theories. Basic quantum chromodynamics phenomenology is covered including momentum dependent effective quark distributions, the transverse momentum cutoff, search for gluons as sources of hadron jets, the status and prospects for the spectroscopy of fundamental fermions and how fermions may be used to probe aspects of the weak and electromagnetic gauge theory, studies of intermediate vector bosons, and miscellaneous possibilities suggested by gauge theories from the Higgs bosons to speculations about proton decay. 187 references

  12. Theory of Langmuir probes in anisotropic plasmas

    International Nuclear Information System (INIS)

    Sudit, I.D.; Woods, R.C.

    1994-01-01

    A theory has been developed for electron retardation by Langmuir probes of several geometries in a general anisotropic plasma with arbitrary probe orientation and valid for any sheath thickness. Electron densities and electron velocity distribution functions (EVDFs) are obtained from the second derivative of probe I-V curves, as in Druyvesteyn's original method, which was developed for isotropic plasmas. Fedorov had extended the latter method in the context of a thin sheath approximation, to axisymmetric plasmas, in which the EVDF is expanded in a series of Legendary polynomials. In the present work an expansion in a series of spherical harmonics is employed, and the coordinate transformations are handled using the irreducible representation of the three dimensional rotation group. It is shown that the Volterra integral equations that must be solved to obtain the expansion coefficients of the EVDF from the second derivative data are no more complicated in the general case that hose for the axisymmetric plasma. Furthermore in the latter case the results can be shown to be equivalent to Fedrov's thin sheath expression. For the case of planar probes a formulation based on first derivatives of the I-V curves has been obtained. If data is obtained at enough different probe orientation of a one sided planar disc probe, any number of spherical harmonic coefficient functions may be obtained by inverting a set of linear equations and the complete EVDF deduced. For a cylindrical probe or a two-sided planar disc probe the integration of the second derivative of the probe current gives the exact electron density with any arbitrary probe orientation and any degree of plasma anisotropy

  13. Probing CP Violation with the Deuteron Electric Dipole Moment

    CERN Document Server

    Lebedev, Oleg; Pospelov, Maxim; Ritz, Adam; Lebedev, Oleg; Olive, Keith A.; Pospelov, Maxim; Ritz, Adam

    2004-01-01

    We present an analysis of the electric dipole moment (EDM) of the deuteron as induced by CP-violating operators of dimension 4, 5 and 6 including theta QCD, the EDMs and color EDMs of quarks, four-quark interactions and the Weinberg operator. We demonstrate that the precision goal of the EDM Collaboration's proposal to search for the deuteron EDM, (1-3)\\times 10^{-27} e cm, will provide an improvement in sensitivity to these sources of one-two orders of magnitude relative to the existing bounds. We consider in detail the level to which CP-odd phases can be probed within the MSSM.

  14. Probing Interfacial Water on Nanodiamonds in Colloidal Dispersion.

    Science.gov (United States)

    Petit, Tristan; Yuzawa, Hayato; Nagasaka, Masanari; Yamanoi, Ryoko; Osawa, Eiji; Kosugi, Nobuhiro; Aziz, Emad F

    2015-08-06

    The structure of interfacial water layers around nanoparticles dispersed in an aqueous environment may have a significant impact on their reactivity and on their interaction with biological species. Using transmission soft X-ray absorption spectroscopy in liquid, we demonstrate that the unoccupied electronic states of oxygen atoms from water molecules in aqueous colloidal dispersions of nanodiamonds have a different signature than bulk water. X-ray absorption spectroscopy can thus probe interfacial water molecules in colloidal dispersions. The impacts of nanodiamond surface chemistry and concentration on interfacial water electronic signature are discussed.

  15. Probing the binding of coumarins and cyclothialidines to DNA gyrase

    DEFF Research Database (Denmark)

    Kampranis, S C; Gormley, N A; Tranter, R

    1999-01-01

    B and coumarin and cyclothialidine drugs and made mutations by site-directed mutagenesis. We used proteolysis as a probe of drug binding to wild-type and mutant proteins. Limited proteolysis of gyrase revealed that binding of these antibiotics is associated with a characteristic proteolytic fingerprint......, suggesting a drug-induced conformational change. The ability of the mutants to bind the drugs was studied by testing their ability to induce the coumarin-associated proteolytic signature and to bind to a novobiocin-affinity column. To analyze further the interaction of the drugs with gyrase, we studied...

  16. Investigations of ultrafast charge dynamics in laser-irradiated targets by a self probing technique employing laser driven protons

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, H. [School of Mathematics and Physics, Queen' s University Belfast, BT7 1NN (United Kingdom); Kar, S., E-mail: s.kar@qub.ac.uk [School of Mathematics and Physics, Queen' s University Belfast, BT7 1NN (United Kingdom); Cantono, G. [School of Mathematics and Physics, Queen' s University Belfast, BT7 1NN (United Kingdom); Department of Physics “E. Fermi”, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Consiglio Nazionale delle Ricerche, Istituto Nazionale di Ottica, Research Unit Adriano Gozzini, via G. Moruzzi 1, Pisa 56124 (Italy); Nersisyan, G. [School of Mathematics and Physics, Queen' s University Belfast, BT7 1NN (United Kingdom); Brauckmann, S. [Institut für Laser-und Plasmaphysik, Heinrich-Heine-Universität, Düsseldorf (Germany); Doria, D.; Gwynne, D. [School of Mathematics and Physics, Queen' s University Belfast, BT7 1NN (United Kingdom); Macchi, A. [Department of Physics “E. Fermi”, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Consiglio Nazionale delle Ricerche, Istituto Nazionale di Ottica, Research Unit Adriano Gozzini, via G. Moruzzi 1, Pisa 56124 (Italy); Naughton, K. [School of Mathematics and Physics, Queen' s University Belfast, BT7 1NN (United Kingdom); Willi, O. [Institut für Laser-und Plasmaphysik, Heinrich-Heine-Universität, Düsseldorf (Germany); Lewis, C.L.S.; Borghesi, M. [School of Mathematics and Physics, Queen' s University Belfast, BT7 1NN (United Kingdom)

    2016-09-01

    The divergent and broadband proton beams produced by the target normal sheath acceleration mechanism provide the unique opportunity to probe, in a point-projection imaging scheme, the dynamics of the transient electric and magnetic fields produced during laser-plasma interactions. Commonly such experimental setup entails two intense laser beams, where the interaction produced by one beam is probed with the protons produced by the second. We present here experimental studies of the ultra-fast charge dynamics along a wire connected to laser irradiated target carried out by employing a ‘self’ proton probing arrangement – i.e. by connecting the wire to the target generating the probe protons. The experimental data shows that an electromagnetic pulse carrying a significant amount of charge is launched along the wire, which travels as a unified pulse of 10s of ps duration with a velocity close to speed of light. The experimental capabilities and the analysis procedure of this specific type of proton probing technique are discussed. - Highlights: • Prompt charging of laser irradiated target generates ultra-short EM pulses. • Its ultrafast propagation along a wire was studied by self-proton probing technique. • Self-proton probing technique is the proton probing with one laser pulse. • Pulse temporal profile and speed along the wire were measured with high resolution.

  17. Gravity Probe B Gyroscope Rotor

    Science.gov (United States)

    2003-01-01

    The Gravity Probe B (GP-B) is the relativity experiment developed at Stanford University to test two extraordinary predictions of Albert Einstein's general theory of relativity. The experiment will measure, very precisely, the expected tiny changes in the direction of the spin axes of four gyroscopes contained in an Earth-orbiting satellite at a 400-mile altitude. So free are the gyroscopes from disturbance that they will provide an almost perfect space-time reference system. They will measure how space and time are very slightly warped by the presence of the Earth, and, more profoundly, how the Earth's rotation very slightly drags space-time around with it. These effects, though small for the Earth, have far-reaching implications for the nature of matter and the structure of the Universe. This photograph is a close up of a niobium-coated gyroscope motor and its housing halves. GP-B is among the most thoroughly researched programs ever undertaken by NASA. This is the story of a scientific quest in which physicists and engineers have collaborated closely over many years. Inspired by their quest, they have invented a whole range of technologies that are already enlivening other branches of science and engineering. Launched April 20, 2004 , the GP-B program was managed for NASA by the Marshall Space Flight Center. Development of the GP-B is the responsibility of Stanford University along with major subcontractor Lockheed Martin Corporation. (Image credit to Don Harley.)

  18. Gravity Probe B Space Vehicle

    Science.gov (United States)

    2003-01-01

    The space vehicle for Gravity Probe B (GP-B) arrives at the launch site at Vandenburg Air Force Base. GP-B is the relativity experiment being developed at Stanford University to test two extraordinary predictions of Albert Einstein's general theory of relativity. The experiment will measure, very precisely, the expected tiny changes in the direction of the spin axes of four gyroscopes contained in an Earth-orbiting satellite at a 400-mile altitude. So free are the gyroscopes from disturbance that they will provide an almost perfect space-time reference system. They will measure how space and time are very slightly warped by the presence of the Earth, and, more profoundly, how the Earth's rotation very slightly drags space-time around with it. These effects, though small for the Earth, have far-reaching implications for the nature of matter and the structure of the Universe. GP-B is among the most thoroughly researched programs ever undertaken by NASA. This is the story of a scientific quest in which physicists and engineers have collaborated closely over many years. Inspired by their quest, they have invented a whole range of technologies that are already enlivening other branches of science and engineering. Scheduled for launch in 2003 and managed for NASA by the Marshall Space Flight Center, development of the GP-B is the responsibility of Stanford University, with major subcontractor Lockheed Martin Corporation.

  19. Probing the string winding sector

    Energy Technology Data Exchange (ETDEWEB)

    Aldazabal, Gerardo; Mayo, Martín [G. Física CAB-CNEA and CONICET, Centro Atómico Bariloche,Av. Bustillo 9500, Bariloche (Argentina); Instituto Balseiro, Centro Atómico Bariloche,Av. Bustillo 9500, Bariloche (Argentina); Nuñez, Carmen [Instituto de Astronomía y Física del Espacio (CONICET-UBA),C.C. 67 - Suc. 28, 1428 Buenos Aires (Argentina); Departamento de Física, FCEN, Universidad de Buenos Aires,C.C. 67 - Suc. 28, 1428 Buenos Aires (Argentina)

    2017-03-17

    We probe a slice of the massive winding sector of bosonic string theory from toroidal compactifications of Double Field Theory (DFT). This string subsector corresponds to states containing one left and one right moving oscillators. We perform a generalized Kaluza Klein compactification of DFT on generic 2n-dimensional toroidal constant backgrounds and show that, up to third order in fluctuations, the theory coincides with the corresponding effective theory of the bosonic string compactified on n-dimensional toroidal constant backgrounds, obtained from three-point amplitudes. The comparison between both theories is facilitated by noticing that generalized diffeomorphisms in DFT allow to fix generalized harmonic gauge conditions that help in identifying the physical degrees of freedom. These conditions manifest as conformal anomaly cancellation requirements on the string theory side. The explicit expression for the gauge invariant effective action containing the physical massless sector (gravity+antisymmetric+gauge+ scalar fields) coupled to towers of generalized Kaluza Klein massive states (corresponding to compact momentum and winding modes) is found. The action acquires a very compact form when written in terms of fields carrying O(n,n) indices, and is explicitly T-duality invariant. The global algebra associated to the generalized Kaluza Klein compactification is discussed.

  20. Probing Light Stops with Stoponium

    CERN Document Server

    Batell, Brian

    2015-01-01

    We derive new limits on light stops from diboson resonance searches in the $\\gamma\\gamma$, $Z \\gamma$, $ZZ$, $WW$ and $hh$ channels from the first run of the LHC. If the two-body decays of the light stop are mildly suppressed or kinematically forbidden, stoponium bound states will form in $pp$ collisions and subsequently decay via the pair annihilation of the constituent stops to diboson final states, yielding striking resonance signatures. Remarkably, we find that stoponium searches are highly complementary to direct collider searches and indirect probes of light stops such as Higgs coupling measurements. Using an empirical quarkonia potential model and including the first two $S$-wave stoponium states, we find that in the decoupling limit $m_{\\widetilde t_1} \\lesssim 130$ GeV is excluded for any value of the stop mixing angle and heavy stop mass by the combination of the latest resonance searches and the indirect constraints. The $\\gamma \\gamma$ searches are the most complementary to the indirect constraint...