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Sample records for microchip ring trap

  1. Trapping ions in a segmented ring trap

    NASA Astrophysics Data System (ADS)

    Tabakov, B. P.; Sterk, J. D.; Benito, F.; Haltli, R.; Tigges, C. P.; Stick, D.; Blain, M. G.; Moehring, D. L.

    2012-06-01

    We demonstrate robust trapping in an ion trap which has a ring shaped RF node. Ions are back-side loaded through a small 10 μm diameter loading hole and we have demonstrated thousands of complete circuits around the trap. Each circuit passes through 44 trapping zones; the trap has 89 independent DC control electrodes. Measurements of the tangential secular frequency indicate a weak dependence on the RF and the loading hole. The ion trap is fabricated using four metal layers, allowing for the inner islanded electrodes to be electrically routed underneath the trap with negligible effects on the trapped ions. [4pt] This work was supported by the Intelligence Advanced Research Projects Activity (IARPA). Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the US Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  2. Gas insulated transmission line having tapered particle trapping ring

    DOEpatents

    Cookson, Alan H.

    1982-01-01

    A gas-insulated transmission line includes an outer sheath, an inner conductor, insulating supports and an insulating gas. A particle-trapping ring is secured to each insulating support, and it is comprised of a central portion and two tapered end portions. The ends of the particle trapping ring have a smaller diameter than the central portion of the ring, so as to enable the use of the particle trapping ring in a curved transmission line.

  3. On-line sample preconcentration and separation technique based on transient trapping in microchip micellar electrokinetic chromatography.

    PubMed

    Sueyoshi, Kenji; Kitagawa, Fumihiko; Otsuka, Koji

    2008-02-15

    This paper describes a novel on-line sample preconcentration and separation technique named transient trapping (tr-trapping), which improves the efficiencies of separation and concentration by using a partially injected short micellar plug in microchip electrophoresis. Although a longer separation length often provides a better resolution of complexed or closely migrating analytes, our proposed theoretical model indicated that a trap-and-release mechanism enables a short micellar zone, which was partially injected into the separation channel, to work as an effective concentration and separation field. Application of the tr-trapping technique to microchip micellar electrokinetic chromatography (MCMEKC) was performed on a newly fabricated 5-way-cross microchip by using sodium dodecyl sulfate and rhodamine dyes as test micelle and analytes, respectively. When the injection times of micelle (t(inj),M) and sample solution (t(inj),S) were 1.0 and 2.0 s, respectively, both the preconcentration and separation of the dyes were completely finished within only 3.0 s. At t(inj),S of 8.0 s, a 393-fold improvement of the detectability was achieved in comparison with conventional MCMEKC. The resolution obtained with tr-trapping-MCMEKC was also better than that with conventional MCMEKC in spite of the 160-fold shorter length of the injected micellar zone at t(inj),M of 1.0 s. These results clearly demonstrated that the tr-trapping technique in MCMEKC provides a rapid, high-resolution and detectability analysis even in the short separation channel on the microchips.

  4. Fabrication and operation of a two-dimensional ion-trap lattice on a high-voltage microchip.

    PubMed

    Sterling, R C; Rattanasonti, H; Weidt, S; Lake, K; Srinivasan, P; Webster, S C; Kraft, M; Hensinger, W K

    2014-04-04

    Microfabricated ion traps are a major advancement towards scalable quantum computing with trapped ions. The development of more versatile ion-trap designs, in which tailored arrays of ions are positioned in two dimensions above a microfabricated surface, will lead to applications in fields as varied as quantum simulation, metrology and atom-ion interactions. Current surface ion traps often have low trap depths and high heating rates, because of the size of the voltages that can be applied to them, limiting the fidelity of quantum gates. Here we report on a fabrication process that allows for the application of very high voltages to microfabricated devices in general and use this advance to fabricate a two-dimensional ion-trap lattice on a microchip. Our microfabricated architecture allows for reliable trapping of two-dimensional ion lattices, long ion lifetimes, rudimentary shuttling between lattice sites and the ability to deterministically introduce defects into the ion lattice.

  5. Multi-ring trap as a reservoir of cooled antiprotons

    SciTech Connect

    Ichioka, T.; Yamazaki, Y.; Higaki, H.; Komaki, K.; Hori, M.; Oshima, N.; Mohri, A.; Kuroki, K.

    1999-12-10

    For the ASACUSA project, a new charged particle trap was designed and constructed. Like a Penning-Malmberg trap, static electric and static magnetic fields are used. Multi-ring electrode is exploited to generate a harmonic potential on the trap axis. It enables the confinement of a number of antiprotons and electrons for the electron cooling. Upon its design, plasma behavior of trapped particle clouds was taken into consideration. As the first step, trap performances have been checked with electrons. Current status are presented.

  6. Trapped particle absorption by the Ring of Jupiter

    NASA Technical Reports Server (NTRS)

    Fillius, W.

    1983-01-01

    The interaction of trapped radiation with the ring of Jupiter is investigated. Because it is an identical problem, the rings of Saturn and Uranus are also examined. Data from the Pioneer II encounter, deductions for some of the properties of the rings of Jupiter and Saturn. Over a dozen Jupiter magnetic field models are available in a program that integrates the adiabatic invariants to compute B and L. This program is to label our UCSD Pioneer II encounter data with the most satisfactory of these models. The expected effects of absorbing material on the trapped radiation are studied to obtain the loss rate as a function of ring properties. Analysis of the particle diffusion problem rounds out the theoretical end of the ring absorption problem. Other projects include identification of decay products for energetic particle albedo off the rings and moons of Saturn and a search for flux transfer events at the Jovian magnetopause.

  7. Trapped particle absorption by the ring of Jupiter

    NASA Technical Reports Server (NTRS)

    Fillius, W.

    1985-01-01

    The ring systems of Jupiter and Saturn, and their interaction with the magnetosphere were studied. Opportunities to improve the understanding of the sweeping effect of orbiting material on trapped radiation, and the use of this process to gain insight on both the trapped radiation and the target material are outlined. Within the cosmogony of Hannes Alfven, this mechanism is also the key to understanding the formation of many of the features of the Saturnian rings. A better understanding of the sweeping effect would also help to clarify this process.

  8. Inducting technique and trapped field in ring-shaped superconductors

    NASA Astrophysics Data System (ADS)

    González-Jorge, H.; Peleteiro, J.; Carballo, E.; Domarco, G.

    2005-12-01

    A comparative study of trapped flux depending on the inducting technique was made in superconducting rings. The inducting procedures used where the traditional field cooling with electromagnet (in this work FC1 or FC2) and the field cooling with a closed magnetic circuit placed through the ring’s hole (FC3). The mentioned study was made by means of flux creep experiences in conventional samples and maps of trapped field in cut samples (current circulation disabled). The current induced in the samples was the critical value and the field trapped in the ring’s wall depended on the magnetic field of FC1, FC2 or FC3. Data obtained from flux creep measurements exhibited the lowest relaxation rate for FC3. On the other hand, maps of trapped field show that the flux trapped was also the lowest when the induction was made by using FC3. The data depicted that samples with similar trapped flux density exhibited similarities in their relaxation rates with very different critical current.

  9. Realization of Translational Symmetry in Trapped Cold Ion Rings

    NASA Astrophysics Data System (ADS)

    Li, Hao-Kun; Urban, Erik; Noel, Crystal; Chuang, Alexander; Xia, Yang; Ransford, Anthony; Hemmerling, Boerge; Wang, Yuan; Li, Tongcang; Häffner, Hartmut; Zhang, Xiang

    2017-02-01

    We crystallize up to 15 40Ca+ ions in a ring with a microfabricated silicon surface Paul trap. Delocalization of the Doppler laser-cooled ions shows that the translational symmetry of the ion ring is preserved at millikelvin temperatures. By characterizing the collective motion of the ion crystals, we identify homogeneous electric fields as the dominant symmetry-breaking mechanism at this energy scale. With increasing ion numbers, such detrimental effects are reduced. We predict that, with only a ten-ion ring, uncompensated homogeneous fields will not break the translational symmetry of the rotational ground state. This experiment opens a door towards studying quantum many-body physics with translational symmetry at the single-particle level.

  10. Initial Plasma Experiment in the Levitated Ring Trap RT-1

    NASA Astrophysics Data System (ADS)

    Saitoh, H.; Yoshida, Z.; Ogawa, Y.; Morikawa, J.; Watanabe, S.; Yano, Y.; Suzuki, J.

    2006-10-01

    Studies on toroidal flowing plasma have started in a superconductor levitated coil device, Ring Trap 1 (RT-1) [1]. RT-1 generates a magnetosphere-like dipole magnetic field configuration that enables various kinds of experiments related to flowing plasmas. The main purpose of the Ring Trap Experiment is to explore a new high-b relaxation state of plasmas predicted by two-fluid relaxation theory of flowing plasmas [2]. Magnetic surface configuration of RT-1 also enables stable pure-magnetic trap of non-neutral plasmas [3], which is potentially suitable for the confinement of charged particles including anti-matters. As an initial experiment, hydrogen plasma is produced by electron cyclotron heating using 8.2GHz microwave generated by a klystron with the maximum power of 100kW for 1s pulse operation. The high-Tc superconductor (Bi-2223) ring with a total coil current of 250kAT is magnetically levitated in a vacuum chamber using a PID feedback control system. The field strength in the trap region is 0.03T to 0.3T. Diagnostics for the RT-1 experiment includes spectroscopy, soft X-ray pulse-height analysis with Si (Li) detector, magnetic probes, and Langmuir probes for edge plasma measurement. The initial experimental results and basic plasma parameters of RT-1 will be presented in the meeting. 1. Z. Yoshida et al., Plasma Fusion Res. 1, 008 (2006). 2. Z. Yoshida and S. M. Mahajan, Phys. Rev. Lett. 88, 095001 (2002). 3. Z. Yoshida, et al., in Nonneutral Plasma Physics III, IV.

  11. Long-lived Dark Solitons in Ring-Trap Condensates

    NASA Astrophysics Data System (ADS)

    Proukakis, Nick; Gallucci, Donatello

    2016-05-01

    We demonstrate the feasibility of generation of quasi-stable counter-propagating solitonic structures in an atomic Bose-Einstein condensate confined in a realistic toroidal geometry, and identify optimal parameter regimes for their experimental observation. Using density engineering we numerically identify distinct regimes of motion of the emerging macroscopic excitations, including both solitonic motion along the azimuthal ring direction, such that structures remain visible after multiple collisions even in the presence of thermal fluctuations, and snaking instabilities leading to the decay of the excitations into vortical structures. Our analysis, which considers both mean field effects and fluctuations, is based on the JQC ring trap geometry. Funding: EPSRC (Grants No. EP/I019413/1 and EP/K03250X/1).

  12. Optically assisted trapping with high-permittivity dielectric rings: Towards optical aerosol filtration

    SciTech Connect

    Alaee, Rasoul; Kadic, Muamer; Rockstuhl, Carsten; Passian, Ali

    2016-10-04

    Controlling the transport, trapping, and filtering of nanoparticles is important for many applications. By virtue of their weak response to gravity and their thermal motion, various physical mechanisms can be exploited for such operations on nanoparticles. However, the manipulation based on optical forces is potentially most appealing since it constitutes a highly deterministic approach. Plasmonic nanostructures have been suggested for this purpose, but they possess the disadvantages of locally generating heat and trapping the nanoparticles directly on the surface. Here, we propose the use of dielectric rings made of high permittivity materials for trapping nanoparticles. Thanks to their ability to strongly localize the field in space, nanoparticles can be trapped without contact. We use a semianalytical method to study the ability of these rings to trap nanoparticles. Lastly, the results are supported by full-wave simulations and application of the trapping concept to nanoparticle filtration is suggested.

  13. Optically assisted trapping with high-permittivity dielectric rings: Towards optical aerosol filtration

    DOE PAGES

    Alaee, Rasoul; Kadic, Muamer; Rockstuhl, Carsten; ...

    2016-10-04

    Controlling the transport, trapping, and filtering of nanoparticles is important for many applications. By virtue of their weak response to gravity and their thermal motion, various physical mechanisms can be exploited for such operations on nanoparticles. However, the manipulation based on optical forces is potentially most appealing since it constitutes a highly deterministic approach. Plasmonic nanostructures have been suggested for this purpose, but they possess the disadvantages of locally generating heat and trapping the nanoparticles directly on the surface. Here, we propose the use of dielectric rings made of high permittivity materials for trapping nanoparticles. Thanks to their ability tomore » strongly localize the field in space, nanoparticles can be trapped without contact. We use a semianalytical method to study the ability of these rings to trap nanoparticles. Lastly, the results are supported by full-wave simulations and application of the trapping concept to nanoparticle filtration is suggested.« less

  14. Gaseous toroid around Saturn. [Saturnian ring system for atomic hydrogen trapping in Titan atmospheric model

    NASA Technical Reports Server (NTRS)

    Mcdonough, T. R.

    1974-01-01

    The trapping of Titan's escaping atmosphere in the Saturnian system by a toroidal ring is discussed. The radius of the toroid is comparable to Titan's orbit, or about ten times larger than the visible rings. Theoretical atmospheric models are formulated that consider Saturn's gravitational attraction and magnetospheric properties in forming this toroid and in protecting toroid particles from direct ionization by solar wind particles.

  15. Highly efficient, versatile, self-Q-switched, high-repetition-rate microchip laser generating Ince-Gaussian modes for optical trapping

    NASA Astrophysics Data System (ADS)

    Dong, Jun; He, Yu; Zhou, Xiao; Bai, Shengchuang

    2016-03-01

    Lasers operating in the Ince-Gaussian (IG) mode have potential applications for optical manipulation of microparticles and formation of optical vortices, as well as for optical trapping and optical tweezers. Versatile, self-Q-switched, high-peak-power, high-repetition-rate Cr, Nd:YAG microchip lasers operating in the IG mode are implemented under tilted, tightly focused laser-diode pumping. An average output power of over 2 W is obtained at an absorbed pump power of 6.4 W. The highest optical-to-optical efficiency of 33.2% is achieved at an absorbed pump power of 3.9 W. Laser pulses with a pulse energy of 7.5 μJ, pulse width of 3.5 ns and peak power of over 2 kW are obtained. A repetition rate up to 335 kHz is reached at an absorbed pump power of 5.8 W. Highly efficient, versatile, IG-mode lasers with a high repetition rate and a high peak power ensure a better flexibility in particle manipulation and optical trapping.

  16. Highly efficient, versatile, self-Q-switched, high-repetition-rate microchip laser generating Ince–Gaussian modes for optical trapping

    SciTech Connect

    Jun Dong; Yu He; Xiao Zhou; Shengchuang Bai

    2016-03-31

    Lasers operating in the Ince-Gaussian (IG) mode have potential applications for optical manipulation of microparticles and formation of optical vortices, as well as for optical trapping and optical tweezers. Versatile, self-Q-switched, high-peak-power, high-repetition-rate Cr, Nd:YAG microchip lasers operating in the IG mode are implemented under tilted, tightly focused laser-diode pumping. An average output power of over 2 W is obtained at an absorbed pump power of 6.4 W. The highest optical-to-optical efficiency of 33.2% is achieved at an absorbed pump power of 3.9 W. Laser pulses with a pulse energy of 7.5 μJ, pulse width of 3.5 ns and peak power of over 2 kW are obtained. A repetition rate up to 335 kHz is reached at an absorbed pump power of 5.8 W. Highly efficient, versatile, IG-mode lasers with a high repetition rate and a high peak power ensure a better flexibility in particle manipulation and optical trapping. (control of laser radiation parameters)

  17. Acceleration and localization of matter in a ring trap

    SciTech Connect

    Bludov, Yu. V.; Konotop, V. V.

    2007-05-15

    A toroidal trap combined with external time-dependent electric field can be used for implementing different dynamical regimes of matter waves. In particular, we show that dynamical and stochastic acceleration, localization, and implementation of the Kapitza pendulum can be originated by means of proper choice of the external force.

  18. Assembling a ring-shaped crystal in a microfabricated surface ion trap

    DOE PAGES

    Stick, Daniel Lynn; Tabakov, Boyan; Benito, Francisco; ...

    2015-09-01

    We report on experiments with a microfabricated surface trap designed for confining a chain of ions in a ring. Uniform ion separation over most of the ring is achieved with a rotationally symmetric design and by measuring and suppressing undesired electric fields. After reducing stray fields, the ions are confined primarily by a radio-frequency pseudopotential and their mutual Coulomb repulsion. As a result, approximately 400 40Ca+ ions with an average separation of 9 μm comprise the ion crystal.

  19. Ring-shaped Wigner crystals of trapped ions at the micronscale

    NASA Astrophysics Data System (ADS)

    Li, Haokun; Urban, Erik; Noel, Crystal; Chuang, Alexander; Xia, Yang; Hemmerling, Borge; Wang, Yuan; Zhang, Xiang; Haeffner, Hartmut

    Trapped ion crystals are ideal platforms to study many-body physics and quantum information processing, with both the internal electronic states and external motional degree-of-freedoms controllable at the single quantum level. In contrast to conventional, finite, linear chains of ions, a ring topology exhibiting periodic boundary conditions and rotational symmetry opens up a new directions to diverse topics. However, previous implementations of ion rings result in small aspect ratios (<0.07) of ion-electrode distance to ring diameter, making the rotational symmetry of the ion crystals prone to stray electric fields from imperfections of the trap electrodes, particularly evident at low temperatures. Here, using a new trap design with a 60-fold improvement of this aspect ratio, we demonstrate crystallization of 40Ca+ ions in a ring with rotational energy barriers comparable to the thermal energy of Doppler laser cooled ion crystals. When further reducing the rotational energy barriers, we observe delocalization of the ion rings. With this result, we enter a regime where quantum topological effects can be studied and novel quantum computation and simulation experiments can be implemented.

  20. Plasticizer contamination from vacuum system O-rings in a quadrupole ion trap mass spectrometer.

    PubMed

    Verge, Kent M; Agnes, George R

    2002-08-01

    The outgassing of plasticizers from Buna-N and Viton o-rings under vacuum lead to undesired ion-molecule chemistry in an Electrospray Quadrupole Ion Trap Mass Spectrometer. In experiments with the helium bath gas pressure >1.2 mTorr, or whenever analyte ions were stored for >100 ms, extensive loss of analyte ions by proton transfer or adduction with o-ring plasticizers bis(2-ethylhexyl) phthalate and bis(2-ethylhexyl) adipate occurred. A temporary solution to this contamination problem was found to be overnight refluxing in hexane of all the o-rings in the vacuum system. This procedure alleviated this plasticizer contamination for approximately 100 hours of operation. These results, and those that lead to identification of the contamination as plasticizers outgassing from o-rings are described.

  1. Assembling a ring-shaped crystal in a microfabricated surface ion trap

    SciTech Connect

    Stick, Daniel Lynn; Tabakov, Boyan; Benito, Francisco; Blain, Matthew; Clark, Craig R.; Clark, Susan; Haltli, Raymond A.; Maunz, Peter; Sterk, Jonathan D.; Tigges, Chris

    2015-09-01

    We report on experiments with a microfabricated surface trap designed for confining a chain of ions in a ring. Uniform ion separation over most of the ring is achieved with a rotationally symmetric design and by measuring and suppressing undesired electric fields. After reducing stray fields, the ions are confined primarily by a radio-frequency pseudopotential and their mutual Coulomb repulsion. As a result, approximately 400 40Ca+ ions with an average separation of 9 μm comprise the ion crystal.

  2. High-throughput sorting and analysis of human sperm with a ring-shaped laser trap.

    PubMed

    Shao, Bing; Shi, Linda Z; Nascimento, Jaclyn M; Botvinick, Elliot L; Ozkan, Mihrimah; Berns, Michael W; Esener, Sadik C

    2007-06-01

    Sperm motility is an important concept in fertility research. To this end, single spot laser tweezers have been used to quantitatively analyze the motility of individual sperm. However, this method is limited with throughput (single sperm per spot), lacks the ability of in-situ sorting based on motility and chemotaxis, requires high laser power (hundreds of milliWatts) and can not be used to dynamically monitor changes in sperm swimming behavior under the influence of a laser beam. Here, we report a continuous 3-D ring-shaped laser trap which could be used for multi-level and high-throughput (tens to hundred sperm per ring) sperm sorting based on their motility and chemotaxis. Under a laser power of only tens of milliWatts, human sperm with low to medium velocity are slowed down, stopped, or forced to change their trajectories to swim along the ring due to the optical gradient force in the radial direction. This is the first demonstration of parallel sperm sorting based on motility with optical trapping technology. In addition, by making the sperm swimming along the circumference of the ring, the effect of laser radiation, optical force and external obstacles on sperm energetics are investigated in a more gentle and quantitative way. The application of this method could be extended to motility and bio-tropism studies of other self-propelled cells, such as algae and bacteria.

  3. Engineering dark solitary waves in ring-trap Bose-Einstein condensates

    NASA Astrophysics Data System (ADS)

    Gallucci, D.; Proukakis, N. P.

    2016-02-01

    We demonstrate the feasibility of generation of quasi-stable counter-propagating solitonic structures in an atomic Bose-Einstein condensate confined in a realistic toroidal geometry, and identify optimal parameter regimes for their experimental observation. Using density engineering we numerically identify distinct regimes of motion of the emerging macroscopic excitations, including both solitonic motion along the azimuthal ring direction, such that structures remain visible after multiple collisions even in the presence of thermal fluctuations, and snaking instabilities leading to the decay of the excitations into vortical structures. Our analysis, which considers both mean field effects and fluctuations, is based on the ring trap geometry of Murray et al (2013 Phys. Rev. A 88 053615).

  4. Observation of magnetic fluctuations and rapid density decay of magnetospheric plasma in Ring Trap 1

    SciTech Connect

    Saitoh, H.; Yoshida, Z.; Morikawa, J.; Yano, Y.; Mikami, H.; Kasaoka, N.; Sakamoto, W.

    2012-06-15

    The Ring Trap 1 device, a magnetospheric configuration generated by a levitated dipole field magnet, has created high-{beta} (local {beta} {approx} 70%) plasma by using electron cyclotron resonance heating (ECH). When a large population of energetic electrons is generated at low neutral gas pressure operation, high frequency magnetic fluctuations are observed. When the fluctuations are strongly excited, rapid loss of plasma was simultaneously observed especially in a quiet decay phase after the ECH microwave power is turned off. Although the plasma is confined in a strongly inhomogeneous dipole field configuration, the frequency spectra of the fluctuations have sharp frequency peaks, implying spatially localized sources of the fluctuations. The fluctuations are stabilized by decreasing the hot electron component below approximately 40%, realizing stable high-{beta} confinement.

  5. The Many-Body Correlation of Bose-Fermi Mixture in the Ring Trap

    NASA Astrophysics Data System (ADS)

    Shibato, Ryosuke; Nishimura, Takushi

    2012-02-01

    Since the realization of Bose-Einstein Condensation in alkali atoms in 1995, studies on cold atomic gases have greatly advanced. The cold atoms are precisely controlled by electromagnetism and optics, and flexible to design quantum systems. In 2001, A. G"orlitz's group has realized the Bose-Einstein condensates in the quasi-one-dimensional system [1]. One have now obtained the ideal system to study the one-dimensional many-body physics experimentally. The purpose of our study is to clarify the effect of quantum many-body correlation beyond the mean-field approximation. To accomplish this purpose, we first prepare the bosons and fermions in the ring trap [2]. We prepare the initial state in the trap with the small distortion and obtained that both kinds of particles tend to be localized. After taking off this distortion, we solved the time-dependent Schr"odinger equation. We derived the energy spectrum, density profile, and studied pair-correlation effect. Our results predict that the many-body correlation emerges, which has never been observed experimentally up to now. [4pt] [1] A. G"orlitz et al., Phys. Rev. Lett. 87, 130402 (2001)[0pt] [2] O. Morizot et al., Phys. Rev. A. 74, 023617 (2006)

  6. Electron Cloud Generation and Trapping in a Quadrupole Magnet at the Los Alamos Proton Storage Ring

    SciTech Connect

    Macek, Robert J.; Browman, Andrew A.; Ledford, John E.; Borden, Michael J.; O'Hara, James F.; McCrady, Rodney C.; Rybarcyk, Lawrence J.; Spickermann, Thomas; Zaugg, Thomas J.; Pivi, Mauro T.F.; /SLAC

    2008-03-17

    Recent beam physics studies on the two-stream e-p instability at the LANL proton storage ring (PSR) have focused on the role of the electron cloud generated in quadrupole magnets where primary electrons, which seed beam-induced multipacting, are expected to be largest due to grazing angle losses from the beam halo. A new diagnostic to measure electron cloud formation and trapping in a quadrupole magnet has been developed, installed, and successfully tested at PSR. Beam studies using this diagnostic show that the 'prompt' electron flux striking the wall in a quadrupole is comparable to the prompt signal in the adjacent drift space. In addition, the 'swept' electron signal, obtained using the sweeping feature of the diagnostic after the beam was extracted from the ring, was larger than expected and decayed slowly with an exponential time constant of 50 to 100 {micro}s. Other measurements include the cumulative energy spectra of prompt electrons and the variation of both prompt and swept electron signals with beam intensity. Experimental results were also obtained which suggest that a good fraction of the electrons observed in the adjacent drift space for the typical beam conditions in the 2006 run cycle were seeded by electrons ejected from the quadrupole.

  7. Ground states of dipolar gases in quasi-one-dimensional ring traps

    SciTech Connect

    Zoellner, Sascha

    2011-12-15

    We compute the ground state of dipoles in a quasi-one-dimensional ring trap using few-body techniques combined with analytical arguments. The effective interaction between two dipoles depends on their center-of-mass coordinate and can be tuned by varying the angle between dipoles and the plane of the ring. For sufficiently weak interactions, the state resembles a weakly interacting Fermi gas or a (inhomogeneous) Lieb-Liniger gas. A mapping between the Lieb-Liniger-gas parameters and the dipolar-gas parameters in and beyond the Born approximation is established, and we discuss the effect of inhomogeneities based on a local-density approximation. For strongly repulsive interactions, the system exhibits a crystal-like localization of the particles. Their inhomogeneous distribution may be understood in terms of a simple few-body model as well as a local-density approximation. In the case of partially attractive interactions, clustered states form for sufficiently strong coupling, and the dependence of the state on particle number and orientation angle of the dipoles is discussed analytically.

  8. High-power actively Q-switched single-mode 1342 nm Nd:YVO4 ring laser, injection-locked by a cw single-frequency microchip laser.

    PubMed

    Koch, Peter; Bartschke, Juergen; L'huillier, Johannes A

    2015-11-30

    In this paper we report on the realization of a single-mode Q-switched Nd:YVO4 ring laser at 1342 nm. Unidirectional and single-mode operation of the ring laser is achieved by injection-locking with a continuous wave Nd:YVO4 microchip laser, emitting a single-frequency power of up to 40 mW. The ring laser provides a single-mode power of 13.9 W at 10 kHz pulse repetition frequency with a pulse duration of 18.2 ns and an excellent beam quality (M2 < 1.05). By frequency doubling of the fundamental 1342 nm laser, a power of 8.7 W at 671 nm with a pulse duration of 14.8 ns and a beam propagation factor of M2 < 1.1 is obtained. The 671 nm radiation features a long-term spectral width of 75 MHz.

  9. Loading an Equidistant Ion Chain in a Ring Shaped Surface Trap and Anomalous Heating Studies with a High Optical Access Trap

    SciTech Connect

    Tabakov, Boyan

    2015-07-01

    Microfabricated segmented surface ion traps are one viable avenue to scalable quantum information processing. At Sandia National Laboratories we design, fabricate, and characterize such traps. Our unique fabrication capabilities allow us to design traps that facilitate tasks beyond quantum information processing. The design and performance of a trap with a target capability of storing hundreds of equally spaced ions on a ring is described. Such a device could aid experimental studies of phenomena as diverse as Hawking radiation, quantum phase transitions, and the Aharonov - Bohm effect. The fabricated device is demonstrated to hold a ~ 400 ion circular crystal, with 9 μm average spacing between ions. The task is accomplished by first characterizing undesired electric fields in the trapping volume and then designing and applying an electric field that substantially reduces the undesired fields. In addition, experimental efforts are described to reduce the motional heating rates in a surface trap by low energy in situ argon plasma treatment that reduces the amount of surface contaminants. The experiment explores the premise that carbonaceous compounds present on the surface contribute to the anomalous heating of secular motion modes in surface traps. This is a research area of fundamental interest to the ion trapping community, as heating adversely affects coherence and thus gate fidelity. The device used provides high optical laser access, substantially reducing scatter from the surface, and thus charging that may lead to excess micromotion. Heating rates for different axial mode frequencies are compared before and after plasma treatment. The presence of a carbon source near the plasma prevents making a conclusion on the observed absence of change in heating rates.

  10. Nuclear cascades in Saturn's rings - Cosmic ray albedo neutron decay and origins of trapped protons in the inner magnetosphere

    NASA Technical Reports Server (NTRS)

    Cooper, J. F.

    1983-01-01

    The nearly equatorial trajectory of the Pioneer 11 spacecraft through Saturn's high energy proton radiation belts and under the main A-B-C rings provided a unique opportunity to study the radial dependence of the greater than 30 MeV proton intensities in the belts in terms of models for secondary nucleon production by cosmic ray interactions in the rings, in situ proton injection in the radiation belts by neutron beta decay, magnetospheric diffusion, and absorption by planetary rings and satellites. Maximum trapped proton intensities measured by Pioneer 11 in the radiation belts are compared with calculated intensities and found consistent with trapping times of roughly 40 years and a radial diffusion coefficient of about 10 to the -15th L to the 9th R sub s squared/s. Differential energy spectra proportional to E to the -2 estimated from integral measurements of trapped photons with E greater than 100 MeV are consistent with the beta decay model, but an inferred turndown of the spectra toward lower energies and reported integral proton anisotropies of a specified form both indicate the need for more realistic calculations of the neutron source from the rings and the radiation belt loss processes.

  11. Nuclear cascades in Saturn's rings - Cosmic ray albedo neutron decay and origins of trapped protons in the inner magnetosphere

    NASA Astrophysics Data System (ADS)

    Cooper, J. F.

    1983-05-01

    The nearly equatorial trajectory of the Pioneer 11 spacecraft through Saturn's high energy proton radiation belts and under the main A-B-C rings provided a unique opportunity to study the radial dependence of the greater than 30 MeV proton intensities in the belts in terms of models for secondary nucleon production by cosmic ray interactions in the rings, in situ proton injection in the radiation belts by neutron beta decay, magnetospheric diffusion, and absorption by planetary rings and satellites. Maximum trapped proton intensities measured by Pioneer 11 in the radiation belts are compared with calculated intensities and found consistent with trapping times of roughly 40 years and a radial diffusion coefficient of about 10 to the -15th L to the 9th Rs squared/s. Differential energy spectra proportional to E to the -2 estimated from integral measurements of trapped photons with E greater than 100 MeV are consistent with the beta decay model, but an inferred turndown of the spectra toward lower energies and reported integral proton anisotropies of a specified form both indicate the need for more realistic calculations of the neutron source from the rings and the radiation belt loss processes.

  12. Nonadiabatic creation of macroscopic superpositions with strongly correlated one-dimensional bosons in a ring trap

    SciTech Connect

    Schenke, C.; Minguzzi, A.; Hekking, F. W. J.

    2011-11-15

    We consider a strongly interacting quasi-one-dimensional Bose gas on a tight ring trap subjected to a localized barrier potential. We explore the possibility of forming a macroscopic superposition of a rotating and a nonrotating state under nonequilibrium conditions, achieved by a sudden quench of the barrier velocity. Using an exact solution for the dynamical evolution in the impenetrable-boson (Tonks-Girardeau) limit, we find an expression for the many-body wave function corresponding to a superposition state. The superposition is formed when the barrier velocity is tuned close to multiples of an integer or half-integer number of Coriolis flux quanta. As a consequence of the strong interactions, we find that (i) the state of the system can be mapped onto a macroscopic superposition of two Fermi spheres rather than two macroscopically occupied single-particle states as in a weakly interacting gas, and (ii) the barrier velocity should be larger than the sound velocity to better discriminate the two components of the superposition.

  13. Persistent currents in coherently coupled Bose-Einstein condensates in a ring trap

    NASA Astrophysics Data System (ADS)

    Abad, Marta

    2016-03-01

    We study the stability of persistent currents in a coherently coupled quasi-two-dimensional Bose-Einstein condensate confined in a ring trap at T =0 . By numerically solving Gross-Pitaevskii equations and by analyzing the excitation spectrum obtained from diagonalization of the Bogoliubov-de Gennes matrix, we describe the mechanisms responsible for the decay of the persistent currents depending on the values of the interaction coupling constants and the Rabi frequency. When the unpolarized system decays due to an energetic instability in the density channel, the spectrum may develop a rotonlike minimum, which gives rise to the finite wavelength excitation necessary for vortex nucleation at the inner surface. When decay in the unpolarized system is driven by spin-density excitations, the finite wavelength naturally arises from the existence of a gap in the excitation spectrum. In the polarized phase of the coherently coupled condensate, there is a hybridization of the excitation modes that leads to complex decay dynamics. In particular, close to the phase transition, a state of broken rotational symmetry is found to be stationary and stable.

  14. Photonic Crystal Microchip Laser

    NASA Astrophysics Data System (ADS)

    Gailevicius, Darius; Koliadenko, Volodymyr; Purlys, Vytautas; Peckus, Martynas; Taranenko, Victor; Staliunas, Kestutis

    2016-09-01

    The microchip lasers, being very compact and efficient sources of coherent light, suffer from one serious drawback: low spatial quality of the beam strongly reducing the brightness of emitted radiation. Attempts to improve the beam quality, such as pump-beam guiding, external feedback, either strongly reduce the emission power, or drastically increase the size and complexity of the lasers. Here it is proposed that specially designed photonic crystal in the cavity of a microchip laser, can significantly improve the beam quality. Experiments show that a microchip laser, due to spatial filtering functionality of intracavity photonic crystal, improves the beam quality factor M2 reducing it by a factor of 2, and increase the brightness of radiation by a factor of 3. This comprises a new kind of laser, the “photonic crystal microchip laser”, a very compact and efficient light source emitting high spatial quality high brightness radiation.

  15. Controlled-release microchips.

    PubMed

    Sharma, Sadhana; Nijdam, A Jasper; Sinha, Piyush M; Walczak, Robbie J; Liu, Xuewu; Cheng, Mark M-C; Ferrari, Mauro

    2006-05-01

    Efficient drug delivery remains an important challenge in medicine: continuous release of therapeutic agents over extended time periods in accordance with a predetermined temporal profile; local delivery at a constant rate to the tumour microenvironment to overcome much of the systemic toxicity and to improve antitumour efficacy; improved ease of administration, and increasing patient compliance required are some of the unmet needs of the present drug delivery technology. Microfabrication technology has enabled the development of novel controlled-release microchips with capabilities not present in the current treatment modalities. In this review, the current status and future prospects of different types of controlled-release microchips are summarised and analysed with reference to microneedle-based microchips, as well as providing an in-depth focus on microreservoir-based and nanoporous microchips.

  16. Photonic Crystal Microchip Laser.

    PubMed

    Gailevicius, Darius; Koliadenko, Volodymyr; Purlys, Vytautas; Peckus, Martynas; Taranenko, Victor; Staliunas, Kestutis

    2016-09-29

    The microchip lasers, being very compact and efficient sources of coherent light, suffer from one serious drawback: low spatial quality of the beam strongly reducing the brightness of emitted radiation. Attempts to improve the beam quality, such as pump-beam guiding, external feedback, either strongly reduce the emission power, or drastically increase the size and complexity of the lasers. Here it is proposed that specially designed photonic crystal in the cavity of a microchip laser, can significantly improve the beam quality. Experiments show that a microchip laser, due to spatial filtering functionality of intracavity photonic crystal, improves the beam quality factor M(2) reducing it by a factor of 2, and increase the brightness of radiation by a factor of 3. This comprises a new kind of laser, the "photonic crystal microchip laser", a very compact and efficient light source emitting high spatial quality high brightness radiation.

  17. Photonic Crystal Microchip Laser

    PubMed Central

    Gailevicius, Darius; Koliadenko, Volodymyr; Purlys, Vytautas; Peckus, Martynas; Taranenko, Victor; Staliunas, Kestutis

    2016-01-01

    The microchip lasers, being very compact and efficient sources of coherent light, suffer from one serious drawback: low spatial quality of the beam strongly reducing the brightness of emitted radiation. Attempts to improve the beam quality, such as pump-beam guiding, external feedback, either strongly reduce the emission power, or drastically increase the size and complexity of the lasers. Here it is proposed that specially designed photonic crystal in the cavity of a microchip laser, can significantly improve the beam quality. Experiments show that a microchip laser, due to spatial filtering functionality of intracavity photonic crystal, improves the beam quality factor M2 reducing it by a factor of 2, and increase the brightness of radiation by a factor of 3. This comprises a new kind of laser, the “photonic crystal microchip laser”, a very compact and efficient light source emitting high spatial quality high brightness radiation. PMID:27683066

  18. Injection, trapping, compression and acceleration of a field-reversed ion ring

    SciTech Connect

    Sudan, R.N. )

    1994-07-20

    A brief review of the Ion Ring concept and its potential applications is followed by a description of a means to axially acclerate Ion Rings to 0.1--1.0 GeV/ion, through a process in which the ring dimensions are on average conserved. [copyright]American Institute of Physics

  19. 10 K Ring Electrode Trap - Tandem Mass Spectrometer for Infrared Spectroscopy of Mass Selected Ions

    SciTech Connect

    Goebbert, Daniel J.; Meijer, Gerard; Asmis, Knut R.

    2009-03-17

    A novel instrumental setup for measuring infrared photodissociation spectra of buffer gas cooled, mass-selected ions is described and tested. It combines a cryogenically cooled, linear radio frequency ion trap with a tandem mass spectrometer, optimally coupling continuous ion sources to pulsed laser experiments. The use of six independently adjustable DC potentials superimposed over the trapping radio frequency field provides control over the ion distribution within, as well as the kinetic energy distribution of the ions extracted from the ion trap. The scheme allows focusing the ions in space and time, such that they can be optimally irradiated by a pulsed, widely tunable infrared photodissociation laser. Ion intensities are monitored with a time-of-flight mass spectrometer mounted orthogonally to the ion trap axis.

  20. Microchip sonic spray ionization.

    PubMed

    Pól, Jaroslav; Kauppila, Tiina J; Haapala, Markus; Saarela, Ville; Franssila, Sami; Ketola, Raimo A; Kotiaho, Tapio; Kostiainen, Risto

    2007-05-01

    The first microchip version of sonic spray ionization (SSI) as an atmospheric pressure ionization source for mass spectrometry (MS) is presented. The microchip used for SSI has recently been developed in our laboratory, and it has been used before as an atmospheric pressure chemical ionization (APCI) and atmospheric pressure photoionization (APPI) source. Now the ionization is achieved simply by applying high (sonic) speed nebulizer gas, without heat, corona discharge, or high voltage. The microchip SSI was applied to the analysis of tetra-N-butylammonium, verapamil, testosterone, angiotensin I, and ibuprofen. The limits of detection were in the range of 15 nM to 4 microM. The technique was found to be highly dependent on the position of the chip toward the mass spectrometer inlet, and on the gas and the sample solution flow rates. The microchip SSI provided dynamic linearity following a pattern similar to that used with electrospray, good quantitative repeatability (RSD=16%), and long-term signal stability.

  1. Formation of high-{beta} plasma and stable confinement of toroidal electron plasma in Ring Trap 1

    SciTech Connect

    Saitoh, H.; Yoshida, Z.; Morikawa, J.; Furukawa, M.; Yano, Y.; Kawai, Y.; Kobayashi, M.; Vogel, G.; Mikami, H.

    2011-05-15

    Formation of high-{beta} electron cyclotron resonance heating plasma and stable confinement of pure electron plasma have been realized in the Ring Trap 1 device, a magnetospheric configuration generated by a levitated dipole field magnet. The effects of coil levitation resulted in drastic improvements of the confinement properties, and the maximum local {beta} value has exceeded 70%. Hot electrons are major component of electron populations, and its particle confinement time is 0.5 s. Plasma has a peaked density profile in strong field region [H. Saitoh et al., 23rd IAEA Fusion Energy Conference EXC/9-4Rb (2010)]. In pure electron plasma experiment, inward particle diffusion is realized, and electrons are stably trapped for more than 300 s. When the plasma is in turbulent state during beam injection, plasma flow has a shear, which activates the diocotron (Kelvin-Helmholtz) instability. The canonical angular momentum of the particle is not conserved in this phase, realizing the radial diffusion of charged particles across closed magnetic surfaces. [Z. Yoshida et al., Phys Rev. Lett. 104, 235004 (2010); H. Saitoh et al., Phys. Plasmas 17, 112111 (2010).].

  2. Ring Enlargement of Three-Membered Boron Heterocycles upon Reaction with Organic π Systems: Implications for the Trapping of Borylenes.

    PubMed

    Krasowska, Małgorzata; Bettinger, Holger F

    2016-07-18

    New low-energy pathways for the reaction between substituted boriranes and borirenes with unsaturated hydrocarbons (ethyne or ethene) were discovered using density functional and coupled cluster theory. The interaction between the π bond of the hydrocarbon and the empty p orbital of the boron center leads to ring expansion of the three-membered to a five-membered boron heterocycle. The reactions are strongly exothermic and have low or even no barriers. They involve intermediates with a pentacoordinate boron center with two hydrocarbon molecules coordinating to boron akin to metal-olefin complexes. These borylene complexes are shallow minima on the potential energy surfaces. But significantly higher barriers for ring formation are computed for 1,5-cyclooctadiene and dibenzocyclooctatetraene complexes of borylenes, making these complexes likely detectable under appropriate experimental conditions. Our computational findings have implications for the interpretation of trapping experiments of thermally generated small borylenes with excess of small π systems. Because of very low barriers for reactions of three-membered boron heterocycles with π systems and the at least locally large excess of the latter under such conditions, formation of five-membered boron heterocycles should be considered.

  3. VCP/p97 Extracts Sterically Trapped Ku70/80 Rings from DNA in Double-Strand Break Repair.

    PubMed

    van den Boom, Johannes; Wolf, Markus; Weimann, Lena; Schulze, Nina; Li, Fanghua; Kaschani, Farnusch; Riemer, Anne; Zierhut, Christian; Kaiser, Markus; Iliakis, George; Funabiki, Hironori; Meyer, Hemmo

    2016-10-06

    During DNA double-strand break (DSB) repair, the ring-shaped Ku70/80 complex becomes trapped on DNA and needs to be actively extracted, but it has remained unclear what provides the required energy. By means of reconstitution of DSB repair on beads, we demonstrate here that DNA-locked Ku rings are released by the AAA-ATPase p97. To achieve this, p97 requires ATP hydrolysis, cooperates with the Ufd1-Npl4 ubiquitin-adaptor complex, and specifically targets Ku80 that is modified by K48-linked ubiquitin chains. In U2OS cells, chemical inhibition of p97 or siRNA-mediated depletion of p97 or its adapters impairs Ku80 removal after non-homologous end joining of DSBs. Moreover, this inhibition attenuates early steps in homologous recombination, consistent with p97-driven Ku release also affecting repair pathway choice. Thus, our data answer a central question regarding regulation of Ku in DSB repair and illustrate the ability of p97 to segregate even tightly bound protein complexes for release from DNA.

  4. Rotational fluxons of Bose-Einstein condensates in coplanar double-ring traps

    SciTech Connect

    Brand, J.; Haigh, T. J.; Zuelicke, U.

    2009-07-15

    Rotational analogs to magnetic fluxons in conventional Josephson junctions are predicted to emerge in the ground state of rotating tunnel-coupled annular Bose-Einstein condensates (BECs). Such topological condensate-phase structures can be manipulated by external potentials. We determine conditions for observing macroscopic quantum tunneling of a fluxon. Rotational fluxons in double-ring BECs can be created, manipulated, and controlled by external potentials in different ways than is possible in the solid-state system, thus rendering them a promising candidate system for studying and utilizing quantum properties of collective many-particle degrees of freedom.

  5. Detection of the superconducting transition and magnetic flux trapping in a niobium micro-ring by using micro-Hall sensors

    NASA Astrophysics Data System (ADS)

    Kahng, Yung Ho; Kim, Yun Won; Kim, Mun Seog; Song, Woon; Choi, Jae-Hyuk; Joo, Sungjung; Hong, Jinki; Rhie, Kungwon; Lee, Soon-Gul

    2016-11-01

    An InAs heterostructure-based micro-Hall sensor was used to study the magnetic properties of a superconducting Nb micro-ring, enabling observation of magnetic phenomena such as diamagnetism onset and magnetic flux trapping in the 20- μm-diameter sample. The superconducting diamagnetism of the micro-ring was observed to develop slowly from T = 7.5 K down to 5 K and showed a notably sharp and substantial drop at 7.0 K, the zero-resistivity temperature obtained from transport measurements on a strip-patterned sample. The observed superconducting transition is discussed in terms of a percolation scenario. In magnetic-field-cooling measurements, the Hall signal from the magnetic flux trapped in the Nb ring at 4.5 K was detected at a sufficiently high level for quantitative comparison with the estimate.

  6. Stationary States and Modulational Instability of Coupled Two-Component Bose-Einstein Condensates in a Ring Trap

    NASA Astrophysics Data System (ADS)

    Deng, Hai-Ming; Zhong, Hong-Hua; Huang, Jia-Hao; Dai, Hui; Yao, Min; Huang, Xiao-Yi

    2015-08-01

    We investigate modulational instability (MI) of a coupled two-component Bose-Einstein condensates in a rotating ring trap. The excitation spectrum and the MI condition of the system are presented analytically. We find that the coupling between the two components strongly modifies the MI condition, and the MI condition is phase-dependent. Furthermore, we discuss the effect of MI on both density excitation and spin excitation. If the inter- and intra-component interaction strengths are all equal, the MI causes density excitation but not spin excitation, and if the inter- and intra-component interaction strengths are different, the MI causes both density excitation and spin excitation. Our results provide a promising approach for controlling the stability and excitation of a rotating two-component Bose-Einstein condensates by modulating its coupling strength and interaction strength. Supported by the National Natural Science Foundation of China under Grant No. 11465008, the Hunan Provincial Natural Science Foundation under Grant No. 2015JJ2114, the Scientific Research Fund of Hunan Provincial Education Department under Grant Nos. 14A118, 13C881, Science and Technology Innovative Research Team in Higher Educational Instituions of Hunan Province, and Science Research Foundation of Xiangnan University under Grant No. 2012-126(41)

  7. Metastable spin textures and Nambu-Goldstone modes of a ferromagnetic spin-1 Bose-Einstein condensate confined in a ring trap

    NASA Astrophysics Data System (ADS)

    Kunimi, Masaya

    2014-12-01

    We investigate the metastability of a ferromagnetic spin-1 Bose-Einstein condensate confined in a quasi-one-dimensional rotating ring trap by solving the spin-1 Gross-Pitaevskii equation. We find analytical solutions that exhibit spin textures. By performing linear stability analysis, it is shown that the solutions can become metastable states. We also find that the number of Nambu-Goldstone modes changes at a certain rotation velocity without changing the continuous symmetry of the order parameter.

  8. Micellar electrokinetic chromatography on microchips.

    PubMed

    Kitagawa, Fumihiko; Otsuka, Koji

    2008-03-01

    This review highlights the methodological and instrumental developments in microchip micellar EKC (MCMEKC) from 1995. The combination of higher separation efficiencies in micellar EKC (MEKC) with high-speed separation in microchip electrophoresis (MCE) should provide high-throughput and high-performance analytical systems. The chip-based separation technique has received considerable attention due to its integration ability without any connector. This advantage allows the development of a multidimensional separation system. Several types of 2-D separation microchips are described in the review. Since complicated channel configurations can easily be fabricated on planar substrates, various sample manipulations can be carried out prior to MCMEKC separations. For example, mixing for on-chip reactions, on-line sample preconcentration, on-chip assay, etc., have been integrated on MEKC microchips. The application of on-line sample preconcentration to MCMEKC can provide not only sensitivity enhancement but also the elucidation of the preconcentration mechanism due to the visualization ability of MCE. The characteristics of these sample manipulations on MEKC microchips are presented in this review. The scope of applications in MCMEKC covers mainly biogenic compounds such as amino acids, peptides, proteins, biogenic amines, DNA, and oestrogens. This review provides a comprehensive table listing the applications in MCMEKC in relation to detection methods.

  9. Microchip problems plague DOD

    NASA Astrophysics Data System (ADS)

    Smith, R. J.

    1984-10-01

    The major issues in the controversy over the discovery of millions of defective microchips sold to the DOD by the Texas Instruments (TI) corporation are outlined. Defects in the microcircuits are blamed on inadequate testing procedures performed by TI during manufacture, and on inadequate testing procedures used by a subcontractor especially contracted to test the chips. Because the problem persisted over a period of years, defects might be possible in as many as 100 million chips used in a broad range of military applications including the Trident submarine, the B-52, B-1B, F-15, F-111, F-4, A-6, and A-7 aircraft, the Harpoon and HARM missile systems, and the Space Shuttles Discovery and Challenger. It is pointed out that although TI has accepted responsibility for the defective chips, little will be done by the DOD to compel the company to replace them, or to upgrade testing procedures. It is concluded that the serious nature of the problem could renew interest in recommendations for the standardization of military microcircuits.

  10. Pioneer 11 observations of trapped particle absorption by the Jovian ring and the satellites 1979, J1, J2, and J3

    SciTech Connect

    Pyle, K.R.; McKibben, R.B.; Simpson, J.A.

    1983-01-01

    Pioneer 10 and 11, during their encounters with Jupiter in 1973 and 1974, penetrated to L values of 2.8 and 1.7, respectively. During these encounters, at several L values, decreases in the intensity of energetic trapped particles were observed, some of which could be explained as due to absorption by the known moons Io and Amalthea; however, some decreases inside L = 4 could not be explained. The recent Voyager 1 and 2 optical discoveries of several new moons and a ring in this region has led us to reexamine our particle data, and we summarize results in this report. We report observations in three channels: protons 0.5--8.7 MeV; electrons >3.4 MeV; and medium-Z nuclei, probably oxygen and sulfur >70 MeV/nucleon. We find that with the additional moons and the ring, all observed intensity features in the stably trapped radiation are accounted for by satellite and ring absorption.

  11. Surface modification in microchip electrophoresis.

    PubMed

    Belder, Detlev; Ludwig, Martin

    2003-11-01

    Different approaches and techniques for surface modification of microfluidic devices applied for microchip electrophoresis are reviewed. The main focus is on the improved electrophoretic separation by reducing analyte-wall interactions and manipulation of electroosmosis. Approaches and methods for permanent and dynamic surface modification of microfluidic devices, manufactured from glass, quartz and also different polymeric substrates, are described.

  12. Analytical Chemistry and the Microchip.

    ERIC Educational Resources Information Center

    Lowry, Robert K.

    1986-01-01

    Analytical techniques used at various points in making microchips are described. They include: Fourier transform infrared spectrometry (silicon purity); optical emission spectroscopy (quantitative thin-film composition); X-ray photoelectron spectroscopy (chemical changes in thin films); wet chemistry, instrumental analysis (process chemicals);…

  13. Extending the applicability of an open-ring trap to perform experiments with a single laser-cooled ion

    SciTech Connect

    Cornejo, J. M.; Colombano, M.; Doménech, J.; Rodríguez, D.; Block, M.; Delahaye, P.

    2015-10-15

    A special ion trap was initially built up to perform β-ν correlation experiments with radioactive ions. The trap geometry is also well suited to perform experiments with laser-cooled ions, serving for the development of a new type of Penning trap, in the framework of the project TRAPSENSOR at the University of Granada. The goal of this project is to use a single {sup 40}Ca{sup +} ion as detector for single-ion mass spectrometry. Within this project and without any modification to the initial electrode configuration, it was possible to perform Doppler cooling on {sup 40}Ca{sup +} ions, starting from large clouds and reaching single ion sensitivity. This new feature of the trap might be important also for other experiments with ions produced at radioactive ion beam facilities. In this publication, the trap and the laser system will be described, together with their performance with respect to laser cooling applied to large ion clouds down to a single ion.

  14. Application of Microchip for Biomarker Analysis

    NASA Astrophysics Data System (ADS)

    Kataoka, Masatoshi; Yatsushiro, Shouki; Yamamura, Shouhei; Abe, Hiroko

    Microchip technologies have received considerable attention, due to their competitive advantages, especially in regards to reduced sample and reagent consumption, analysis time, and easy operation. This approach has been successfully used to analyze DNA, amino acids, proteins, and carbohydrates. In the present study, we showed the potential of microchip technologies for the biomarker analysis, blood carbohydrate analysis on microchip electrophoresis, quantitative analysis of protein with antigen-antibody reaction on microchip, and the detection of malaria-infected erythrocyte with a cell microarray chip.

  15. Barcoded microchips for biomolecular assays.

    PubMed

    Zhang, Yi; Sun, Jiashu; Zou, Yu; Chen, Wenwen; Zhang, Wei; Xi, Jianzhong Jeff; Jiang, Xingyu

    2015-01-20

    Multiplexed assay of analytes is of great importance for clinical diagnostics and other analytical applications. Barcode-based bioassays with the ability to encode and decode may realize this goal in a straightforward and consistent manner. We present here a microfluidic barcoded chip containing several sets of microchannels with different widths, imitating the commonly used barcode. A single barcoded microchip can carry out tens of individual protein/nucleic acid assays (encode) and immediately yield all assay results by a portable barcode reader or a smartphone (decode). The applicability of a barcoded microchip is demonstrated by human immunodeficiency virus (HIV) immunoassays for simultaneous detection of three targets (anti-gp41 antibody, anti-gp120 antibody, and anti-gp36 antibody) from six human serum samples. We can also determine seven pathogen-specific oligonucleotides by a single chip containing both positive and negative controls.

  16. Particle-free microchip processing

    DOEpatents

    Geller, A.S.; Rader, D.J.

    1996-06-04

    Method and apparatus for reducing particulate contamination in microchip processing are disclosed. The method and apparatus comprise means to reduce particle velocity toward the wafer before the particles can be deposited on the wafer surface. A reactor using electric fields to reduce particle velocity and prevent particulate contamination is disclosed. A reactor using a porous showerhead to reduce particle velocities and prevent particulate contamination is disclosed. 5 figs.

  17. Particle-free microchip processing

    DOEpatents

    Geller, Anthony S.; Rader, Daniel J.

    1996-01-01

    Method and apparatus for reducing particulate contamination in microchip processing are disclosed. The method and apparatus comprise means to reduce particle velocity toward the wafer before the particles can be deposited on the wafer surface. A reactor using electric fields to reduce particle velocity and prevent particulate contamination is disclosed. A reactor using a porous showerhead to reduce particle velocities and prevent particulate contamination is disclosed.

  18. Microchips in Medicine: Current and Future Applications.

    PubMed

    Eltorai, Adam E M; Fox, Henry; McGurrin, Emily; Guang, Stephanie

    2016-01-01

    With the objective of improving efficacy and morbidity, device manufacturers incorporate chemicals or drugs into medical implants. Using multiple reservoirs of discrete drug doses, microchips represent a new technology capable of on-demand release of various drugs over long periods of time. Herein, we review drug delivery systems, how microchips work, recent investigations, and future applications in various fields of medicine.

  19. Production of Microchips from Polystyrene Plates

    ERIC Educational Resources Information Center

    Pace, Sarah Lindsey

    2009-01-01

    Currently manufactured microchips are expensive to make, require specialized equipment, and leave a large environmental footprint. To counter this, an alternative procedure that is cheaper and leaves a smaller environmental footprint should be made. The goal of this research project is to develop a process that creates microchips from polystyrene…

  20. Microchips in Medicine: Current and Future Applications

    PubMed Central

    Eltorai, Adam E. M.; Fox, Henry; McGurrin, Emily; Guang, Stephanie

    2016-01-01

    With the objective of improving efficacy and morbidity, device manufacturers incorporate chemicals or drugs into medical implants. Using multiple reservoirs of discrete drug doses, microchips represent a new technology capable of on-demand release of various drugs over long periods of time. Herein, we review drug delivery systems, how microchips work, recent investigations, and future applications in various fields of medicine. PMID:27376079

  1. Efficient proteolysis strategies based on microchip bioreactors.

    PubMed

    Liu, Shuang; Bao, Huimin; Zhang, Luyan; Chen, Gang

    2013-04-26

    In proteome research, proteolysis is an important procedure prior to the mass spectrometric identification of proteins. The typical time of conventional in-solution proteolysis is as long as several hours to half a day. To enhance proteolysis efficiency, a variety of microchip bioreactors have been developed for the rapid digestion and identification of proteins in the past decade. This review mainly focuses on the recent advances and the key strategies of microchip bioreactors in protein digestion. The subjects covered include microchip proteolysis systems, the immobilization of proteases in microchannels, the applications of microchip bioreactors in highly efficient proteolysis, and future prospects. It is expected that microchip bioreactors will become powerful tools in protein analysis and will find a wide range of applications in high-throughput protein identification.

  2. Microchip electrophoresis for chiral separations.

    PubMed

    Belder, Detlev; Ludwig, Martin

    2003-08-01

    Microchip electrophoresis (MCE) is a promising new technique for the separation of enantiomers. This recently introduced technique enables chiral separations to be performed in seconds on tiny micromachined devices. This review is intended to give a brief introduction into the principles of chiral separations with MCE with regard to methodology and instrumentation. Different approaches to realize chiral separations in microfluidic devices are described and discussed. This review gives an overview of original work done in this field with emphasis on approaches to improve detection and resolution in chiral MCE.

  3. Global images of trapped ring current ions during main phase of 17 March 2015 geomagnetic storm as observed by TWINS

    NASA Astrophysics Data System (ADS)

    Perez, J. D.; Goldstein, J.; McComas, D. J.; Valek, P.; Fok, M.-C.; Hwang, Kyoung-Joo

    2016-07-01

    A unique view of the trapped particles in the inner magnetosphere provided by energetic neutral atom (ENA) imaging is used to observe the dynamics of the spatial structure and the pitch angle anisotropy on a global scale during the last 6 h of the main phase of a large geomagnetic storm (minimum SYM-H = -230 nT) that began on 17 March 2015. Ion flux and pressure anisotropy obtained from Two Wide-angle Imaging Neutral-atom Spectrometers (TWINS) ENA images are shown. The ion flux shows two peaks, an inner one at approximately radii = 3-4 RE in the dusk-to-midnight sector and an outer peak at radii = 8-9 RE prior to midnight. The inner peak is relatively stationary during the entire period with some intensification during the final steep decline in SYM-H to its minimum. The outer peak shows the significant temporal variation brightening and dimming and finally disappearing at the end of the main phase. The pressure anisotropy shows the expected perpendicular pitch angles inside of L = 6 but shows parallel pitch angles at greater L values. This is interpreted as consistent with pitch angle-dependent drift as modeled in the Tsy05 magnetic field and Comprehensive Inner Magnetosphere-Ionosphere simulations. The TWINS results are compared directly with Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE)-A measurements. Using 15 min snapshots of flux and pressure anisotropy from TWINS along the path of RBSPICE-A during the 6 h focused upon in this study, the essential features displayed in the TWINS global images are supported.

  4. Global Images of Trapped Ring Current Ions During Main Phase of 17 March 2015 Geomagnetic Storm as Observed by TWINS

    NASA Technical Reports Server (NTRS)

    Perez, J. D.; Goldstein, J.; McComas, D. J.; Valek, P.; Fok, Mei-Ching; Hwang, Kyoung-Joo

    2016-01-01

    A unique view of the trapped particles in the inner magnetosphere provided by energetic neutral atom (ENA) imaging is used to observe the dynamics of the spatial structure and the pitch angle anisotropy on a global scale during the last 6 h of the main phase of a large geomagnetic storm (minimum SYM-H 230 nT) that began on 17 March 2015. Ion flux and pressure anisotropy obtained from Two Wide-angle Imaging Neutral-atom Spectrometers (TWINS) ENA images are shown. The ion flux shows two peaks, an inner one at approximately radii 34 RE in the dusk-to-midnight sector and an outer peak at radii 89 RE prior to midnight. The inner peak is relatively stationary during the entire period with some intensification during the final steep decline in SYM-H to its minimum. The outer peak shows the significant temporal variation brightening and dimming and finally disappearing at the end of the main phase. The pressure anisotropy shows the expected perpendicular pitch angles inside of L 6 but shows parallel pitch angles at greater L values. This is interpreted as consistent with pitch angle-dependent drift as modeled in the Tsy05 magnetic field and Comprehensive Inner Magnetosphere-Ionosphere simulations. The TWINS results are compared directly with Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE)-A measurements. Using 15 min snapshots of flux and pressure anisotropy from TWINS along the path of RBSPICE-A during the 6 h focused upon in this study, the essential features displayed in the TWINS global images are supported.

  5. Liquid phase chromatography on microchips.

    PubMed

    Kutter, Jörg P

    2012-01-20

    Over the past twenty years, the field of microfluidics has emerged providing one of the main enabling technologies to realize miniaturized chemical analysis systems, often referred to as micro-Total Analysis Systems (uTAS), or, more generally, Lab-on-a-Chip Systems (LOC) [1,2]. While microfluidics was driven forward a lot from the engineering side, especially with respect to ink jet and dispensing technology, the initial push and interest from the analytical chemistry community was through the desire to develop miniaturized sensors, detectors, and, very early on, separation systems. The initial almost explosive development of, in particular, chromatographic separation systems on microchips, has, however, slowed down in recent years. This review takes a closer, critical look at how liquid phase chromatography has been implemented in miniaturized formats over the past several years, what is important to keep in mind when developing or working with separations in a miniaturized format, and what challenges and pitfalls remain.

  6. Signal enhancement using a switchable magnetic trap

    DOEpatents

    Beer, Neil Reginald [Pleasanton, CA

    2012-05-29

    A system for analyzing a sample including providing a microchannel flow channel; associating the sample with magnetic nanoparticles or magnetic polystyrene-coated beads; moving the sample with said magnetic nanoparticles or magnetic polystyrene-coated beads in the microchannel flow channel; holding the sample with the magnetic nanoparticles or magnetic polystyrene-coated beads in a magnetic trap in the microchannel flow channel; and analyzing the sample obtaining an enhanced analysis signal. An apparatus for analysis of a sample includes magnetic particles connected to the sample, a microchip, a flow channel in the microchip, a source of carrier fluid connected to the flow channel for moving the sample in the flow channel, an electromagnet trap connected to the flow line for selectively magnetically trapping the sample and the magnetic particles, and an analyzer for analyzing the sample.

  7. Application of Microchip Electrophoresis for Clinical Tests

    NASA Astrophysics Data System (ADS)

    Yatsushiro, Shouki; Kataoka, Masatoshi

    Microchip electrophoresis has recently attracted much attention in the field of nuclear acid analysis due to its high efficiency, ease of operation, low consumption of samples and reagents, and relatively low costs. In addition, the analysis has expanded to an analytical field like not only the analysis of DNA but also the analysis of RNA, the protein, the sugar chain, and the cellular function, etc. In this report, we showed that high-performance monitoring systems for human blood glucose levels and α-amylase activity in human plasma using microchip electrophoresis.

  8. Evaluation of microchip material and surface treatment options for IEF of allergenic milk proteins on microchips.

    PubMed

    Poitevin, Martine; Shakalisava, Yuliya; Miserere, Sandrine; Peltre, Gabriel; Viovy, Jean-Louis; Descroix, Stephanie

    2009-12-01

    The use of glass and PDMS microchips has been investigated to perform rapid and efficient separation of allergenic whey proteins by IEF. To decrease EOF and to limit protein adsorption, two coating procedures have been compared. The first one consists in immobilizing hydroxypropyl cellulose (HPC) and the second one poly(dimethylacrylamide-co-allyl glycidyl ether) (PDMA-AGE). EOF limitation has been evaluated using frontal electrophoresis of a fluorescent marker of known effective mobility. EOF velocity was decreased by a factor about 100 and 30, respectively. pH gradient formation has been evaluated for each microchip using fluorescent pI markers. It was demonstrated that as expected a coating was essential to avoid pH gradient drift. Both coatings were efficient on glass microchips, but only PDMA-AGE allowed satisfying focusing of pI markers on PDMS microchips. Fluorescent covalent and noncovalent labelings of milk proteins have been compared by IEF on slab-gels. IEF separation of three major allergenic whey proteins [beta-lactoglobulin A (pI 5.25) and B (pI 5.35) and alpha-lactalbumin (pI 4.2-4.5)] was performed in both microchips. Milk proteins were separated with better resolution and shorter analysis time than by classical CIEF. Finally, better resolutions for milk allergens separation were obtained on glass microchips.

  9. On-Campus Projects: Inventing a Microchip.

    ERIC Educational Resources Information Center

    Basta, Nicholas

    1985-01-01

    In response to growth of microelectronics and changes in microchip design/manufacturing technology, universities are supporting class projects for students. Approximately 50 schools now conduct such programs which have resulted from earlier National Science Foundation sponsorship. Major advantages for the students include designing experience,…

  10. Comparison of surface and hydrogel-based protein microchips.

    PubMed

    Zubtsov, D A; Savvateeva, E N; Rubina, A Yu; Pan'kov, S V; Konovalova, E V; Moiseeva, O V; Chechetkin, V R; Zasedatelev, A S

    2007-09-15

    Protein microchips are designed for high-throughput evaluation of the concentrations and activities of various proteins. The rapid advance in microchip technology and a wide variety of existing techniques pose the problem of unified approach to the assessment and comparison of different platforms. Here we compare the characteristics of protein microchips developed for quantitative immunoassay with those of antibodies immobilized on glass surfaces and in hemispherical gel pads. Spotting concentrations of antibodies used for manufacturing of microchips of both types and concentrations of antigen in analyte solution were identical. We compared the efficiency of antibody immobilization, the intensity of fluorescence signals for both direct and sandwich-type immunoassays, and the reaction-diffusion kinetics of the formation of antibody-antigen complexes for surface and gel-based microchips. Our results demonstrate higher capacity and sensitivity for the hydrogel-based protein microchips, while fluorescence saturation kinetics for the two types of microarrays was comparable.

  11. Integration of valving and sensing on a capillary-assembled microchip.

    PubMed

    Hisamoto, Hideaki; Funano, Shun-ichi; Terabe, Shigeru

    2005-04-01

    A simple integration of both flow control valves and a reaction-based sensing function on a single microchip was performed by using capillary-assembled microchip (CAs-CHIP: Hisamoto, H.; Nakashima, Y.; Kitamura, C.; Funano, S.-i.; Yasuoka, M.; Morishima, K.; Kikutani, Y.; Kitamori, T.; Terabe, S. Anal. Chem. 2004, 76, 3222-3228.). In contrast to the previously reported on-chip valving systems, where the simple valving functions were integrated, our system can integrate not only valving function but also many other chemical functions to perform a complex chemical operation on a single microchip. Here, an enzymatic reaction-based readout system is employed as an example. A square capillary immobilizing N-isopropylacrylamide polymer monolith (referred to as "valving capillary") is used as a thermoresponsive "valving part" and the immobilizing enzyme-modified glycidyl methacrylate polymer monolith (referred to as "sensing capillary") is used as a "sensing part" of the CAs-CHIP. These capillaries are embedded into a lattice microchannel network fabricated on poly(dimethylsiloxane), which has the same channel dimensions as the outer dimensions of the square capillaries. After bonding, a small Peltier device (2 mm x 2 mm) for temperature control is placed on the embedded valving capillaries to control fluid flow. Using this for heating or cooling, fast operation times of 1.4 and 3.2 s for opening and closing valves, respectively, are successfully achieved. Finally, two valving capillaries are independently controlled to trap sample solution within a bypass channel, where the enzyme-immobilized capillary is embedded, and then enzymatic reaction-based sensing of chemical species is performed as an example. The fundamental characteristics of the valve-integrated microchip are fully investigated, and an application to the analysis of an enzyme substrate by using two independent valving capillaries and a sensing capillary is demonstrated.

  12. Microchip Capillary Electrophoresis with Electrochemical Detection for Monitoring Environmental Pollutants

    SciTech Connect

    Chen, Gang; Lin, Yuehe; Wang, Joseph

    2006-01-15

    This invited paper reviews recent advances and the key strategies in microchip capillary electrophoresis (CE) with electrochemical detection (ECD) for separating and detecting a variety of environmental pollutants. The subjects covered include the fabrication of microfluidic chips, sample pretreatments, ECD, typical applications of microchip CE with ECD in environmental analysis, and future prospects. It is expected that microchip CE-ECD will become a powerful tool in the environmental field and will lead to the creation of truly portable devices.

  13. Microchip capillary electrophoresis-electrospray ionization-mass spectrometry of intact proteins using uncoated Ormocomp microchips.

    PubMed

    Sikanen, Tiina; Aura, Susanna; Franssila, Sami; Kotiaho, Tapio; Kostiainen, Risto

    2012-01-20

    We present rapid (<5 min) and efficient intact protein analysis by mass spectrometry (MS) using fully microfabricated and monolithically integrated capillary electrophoresis-electrospray ionization (CE-ESI) microchips. The microchips are fabricated fully of commercial inorganic-organic hybrid material, Ormocomp, by UV-embossing and adhesive Ormocomp-Ormocomp bonding (CE microchannels). A sheath-flow ESI interface is monolithically integrated with the UV-embossed separation channels by cutting a rectangular emitter tip in the end with a dicing saw. As a result, electrospray was produced from the corner of chip with good reproducibility between parallel tips (stability within 3.8-9.2% RSD). Thanks to its inherent biocompatibility and stable (negative) surface charge, Ormocomp microchips enable efficient intact protein analysis with up to ∼10(4) theoretical separation plates per meter without any chemical or physical surface modification before analysis. The same microchip setup is also feasible for rapid peptide sequencing and mass fingerprinting and shows excellent migration time repeatability from run to run for both peptides (5.6-5.9% RSD, n=4) and intact proteins (1.3-7.5% RSD, n=3). Thus, the Ormocomp microchips provide a versatile new tool for MS-based proteomics. Particularly, the feasibility of the Ormocomp chips for rapid analysis of intact proteins with such a simple setup is a valuable increment to the current technology.

  14. Monitoring environmental pollutants by microchip capillary electrophoresis with electrochemical detection

    SciTech Connect

    Chen, Gang; Lin, Yuehe; Wang, Joseph

    2006-01-15

    This is a review article. During the past decade, significant progress in the development of miniaturized microfluidic systems has Occurred due to the numerous advantages of microchip analysis. This review focuses on recent advances and the key strategies in microchip capillary electrophoresis (CE) with electrochemical detection (ECD) for separating and detecting a variety of environmental pollutants. The subjects covered include the fabrication of microfluidic chips, ECD, typical applications of microchip CE with ECD in environmental analysis, and future prospects. It is expected that microchip CE-ECD will become a powerful tool in the environmental field and will lead to the creation of truly portable devices.

  15. Adaptive nanowires for switchable microchip devices.

    PubMed

    Piccin, Evandro; Laocharoensuk, Rawiwan; Burdick, Jared; Carrilho, Emanuel; Wang, Joseph

    2007-06-15

    This paper demonstrates for the first time the use of adaptive functional nickel nanowires for switching on-demand operation of microfluidic devices. Controlled reversible magnetic positioning and orientation of these nanowires at the microchannel outlet offers modulation of the detection and separation processes, respectively. The former facilitates switching between active and passive detection states to allow the microchip to be periodically activated to perform a measurement and reset it to the passive ("off") state between measurements. Fine magnetic tuning of the separation process (postchannel broadening of the analyte zone) is achieved by reversibly modulating the nanowire orientation (i.e., detector alignment) at the channel outlet. The concept can be extended to other microchip functions and stimuli-responsive materials and holds great promise for regulating the operation of microfluidic devices in reaction to specific needs or unforeseen scenarios.

  16. Nanostructured optical microchips for cancer biomarker detection.

    PubMed

    Zhang, Tianhua; He, Yuan; Wei, Jianjun; Que, Long

    2012-01-01

    Herein we report the label-free detection of a cancer biomarker using newly developed arrayed nanostructured Fabry-Perot interferometer (FPI) microchips. Specifically, the prostate cancer biomarker free prostate-specific antigen (f-PSA) has been detected with a mouse anti-human PSA monoclonal antibody (mAb) as the receptor. Experiments found that the limit-of-detection of current nanostructured FPI microchip for f-PSA is about 10 pg/mL and the upper detection range for f-PSA can be dynamically changed by varying the amount of the PSA mAb immobilized on the sensing surface. The control experiments have also demonstrated that the immunoassay protocol used in the experiments shows excellent specificity and selectivity, suggesting the great potential to detect the cancer biomarkers at trace levels in complex biofluids. In addition, given its nature of low cost, simple-to-operation and batch fabrication capability, the arrayed nanostructured FPI microchip-based platform could provide an ideal technical tool for point-of-care diagnostics application and anticancer drug screen and discovery.

  17. Mini-electrochemical detector for microchip electrophoresis.

    PubMed

    Jiang, Lei; Lu, Yao; Dai, Zhongpeng; Xie, Minhao; Lin, Bingcheng

    2005-09-01

    This paper presents the development of a mini-electrochemical detector for microchip electrophoresis. The small size (3.6 x 5.0 cm2, W x L) of the detector is compatible with the dimension of the microchip. The use of universal serial bus (USB) ports facilitates installation and use of the detector, miniaturizes the detector, and makes it ideal for lab-on-a-chip applications. A fixed 10 M ohm feedback resistance was chosen to convert current of the working electrode to voltage with second gain of 1, 2, 4, 8, 16, 32, 64 and 128 for small signal detection instead of adopting selectable feedback resistance. Special attention has been paid to the power support circuitry and printed circuit board (PCB) design in order to obtain good performance in such a miniature size. The working electrode potential could be varied over a range of +/-2.5 V with a resolution of 0.01 mV. The detection current ranges from -0.3 x 10(-7) A to 2.5 x 10(-7) A and the noise is lower than 1 pA. The analytical performance of the new system was demonstrated by the detection of epinephrine using an integrated PDMS/glass microchip with detection limit of 2.1 microM (S/N = 3).

  18. Silicon-on-glass based microchip for protein sensing and analysis by using confocal microscopy and MALDI-TOF

    NASA Astrophysics Data System (ADS)

    Kim, M. S.; Cho, S. H.; Kim, B. G.; Kim, Y. K.

    2006-01-01

    We propose a prototype of silicon-on-glass microchip for protein detection by bead-based affinity chromatography. The microchip has five channels integrated by composing one beads reactor per one channel. Especially, an effective protein analysis mechanism is presented where the three protein-pretreatment processes are simultaneously performed on a single beads reactor: selective detection (purification / sensing), pre-concentration and protein digestion. Since the five channels are closely spaced in parallel on the microchip, it is possible to inspect the five different detection results on real-time in a single microscope image. The microchip is fabricated on silicon-on-glass (SiOG) to make a mechanically strong and vertically transparent structure for efficient fluid interconnection and fluorescence detection, respectively. Within the microchip, the grid-type filter is formed on channel output to physically trap 38 ~ 50 μm diameter microbeads. The dimension of one grid is 30 × 30 μm2. The volume flow rate was investigated experimentally on the case of bead-packed chamber, and the resulted value was compared to that of the case of hollow chamber. In this research, we used self-cleavage free aptazymes as detection ligands immobilized on polystyrene microbeads. The target proteins are firstly on-chip concentrated and fluorescence-detected (confocal microscopy), and secondly checked off-chip by using MALDI-TOF. If the two analyses are used cooperatively, it is expected that the accuracy in diagnostic analysis will be enhanced in biosensing system. Especially by using this free aptazymes system, we don't need to consider the requirement of fluorescence tagging and the difficulty of eluting antibody-bound proteins from microbeads without bad effects of harsh elution conditions in protease treatment. We analyzed the on-bead detection of HCV replicase and HCV helicase respectively by measuring fluorescence intensities at different concentrations, and also performed a

  19. Pioneer 11 observations of trapped particle absorption by the Jovian ring and the satellites 1979, J1, J2, and J3

    NASA Technical Reports Server (NTRS)

    Pyle, K. R.; Mckibben, R. B.; Simpson, J. A.

    1983-01-01

    Pioneer 11 low energy telescope observation of charged particles around the Jovian satellites Amalthea, 1979 J1, J2, and J3, and the Jupiter ring are examined in the light of Voyager optical data from the same region. Good agreement was found in the absorption features of 0.5-8.7 MeV protons, electrons with energies of 3.4 MeV or more, and medium-Z nuclei. The heavier nuclei are suggested to be oxygen and sulfur particles with energies exceeding 70 MeV/nucleon. The observed intensity features in the regularly spaced radiation bands are interpreted as ring and satellite absorption.

  20. Recent innovations in protein separation on microchips by electrophoretic methods.

    PubMed

    Peng, Youyuan; Pallandre, Antoine; Tran, N Thuy; Taverna, Myriam

    2008-01-01

    Microchips for analytical purposes have attracted great attention over the last 20 years. In the present review, we focus on the most recent development of microchips for electrophoretic separation of proteins. This review starts with a short recalling about the microchips covering the basic microchip layout for CE and the commercial chips and microchip platforms. A short paragraph is dedicated to the surface treatment of microchips, which is of paramount importance in protein analysis. One section is dedicated to on-line sample pretreatment in microchips and summarizes different strategies to pre-concentrate or to purify proteins from complex matrixes. Most of the common modes used for CE of proteins have already been adapted to the chip format, while multidimensional approaches are still in progress. The different routes to achieve detection in microchip are also presented with a special attention to derivatization or labeling of proteins. Finally, several recent applications are mentioned. They highlight the great potential of electrophoretic separations of proteins in numerous fields such as biological, pharmaceutical or agricultural and food analysis. A bibliography with 151 references is provided covering papers published from 2000 to the early 2007.

  1. Bulk modification of PDMS microchips by an amphiphilic copolymer.

    PubMed

    Xiao, Yan; Yu, Xiao-Dong; Xu, Jing-Juan; Chen, Hong-Yuan

    2007-09-01

    A simple and rapid bulk-modification method based on adding an amphiphilic copolymer during the fabrication process was employed to modify PDMS microchips. Poly(lactic acid)-poly(ethylene glycol) (PLA-PEG) was used as the additive substance. Compared to the native PDMS microchips, both the contact angle and the EOF of the bulk-modified PDMS microchips decreased. The effects of the additive loading and the pH on the EOF were investigated in detail. The bulk-modified PDMS microchips exhibited reproducible and stable EOF behavior. The application of the bulk-modified PDMS microchips was also studied and the results indicated that they could be successfully used to separate amino acids and to suppress protein adsorption.

  2. IATROGENIC MICROCHIP ARTERIAL EMBOLISM IN A CHILEAN FLAMINGO (PHOENICOPTERUS CHILENSIS).

    PubMed

    Olds, June E; Ewing, Jacob; Arruda, Paulo; Kuyper, Jennifer; Riedesel, Elizabeth; Miles, Kristina M

    2016-06-01

    Aberrant microchip migration has been reported in domestic animal species, but in most cases, this migration is atraumatic to the patient. Reports of microchip-associated trauma and sarcoma development also have been reported in a variety of mammal species. This report describes accidental arterial microchip insertion causing obstruction of the iliac artery in a Chilean flamingo (Phoenicopterus chilensis). Diagnostic imaging included digital radiography and pre- and post-contrast computed tomography to determine the location of the microchip. Surgical removal of the microchip was attempted; however, the flamingo died intraoperatively. Postmortem evaluation found trauma to the epicardium, without penetration of the ventricle. The descending aorta was found traumatized and identified as the most likely insertion point leading to the embolism.

  3. [Microchips based on three dimensional gel cells: history and perspective].

    PubMed

    Kolchinskiĭ, A M; Griadunov, D A; Lysov, Iu P; Mikhaĭlovich, V M; Nasedkina, T V; Turygin, A Iu; Rubina, A Iu; Barskiĭ, V E; Zasedatelev, A S

    2004-01-01

    The review describes the history of creation and development of the microchip technology and its role in the human genome project in Russia. The emphasis is placed on the three-dimensional gel-based microchips developed at the Center of Biological Microchips headed by A.D. Mirzabekov since 1988. The gel-based chips of the last generation, IMAGE chips (Immobilized Micro Array of Gel Elements), have a number of advantages over the previous versions. The microchips are manufactured by photo-initiated copolymerization of gel components and immobilized molecules (DNA, proteins, and ligands). This ensures an even distribution of the immobilized probe throughout the microchip gel element with a high yield (about 50% for oligonucleotides). The use of methacrylamide as a main component of the polymerization mixture resulted in a substantial increase of gel porosity without affecting its mechanical strength and stability, which allowed one to work with the DNA fragments of up to 500 nt in length, as well as with rather large protein molecules. At present, the gel-based microchips are widely applied to address different problems. The generic microchips containing a complete set of possible hexanucleotides are used to reveal the DNA motifs binding with different proteins and to study the DNA-protein interactions. The oligonucleotide microchips are a cheap and reliable tool of diagnostics designed for mass application. Biochips have been developed for identification of the tuberculosis pathogen and its antibiotic-resistant forms; for diagnostics of orthopoxviruses, including the smallpox virus; for diagnostics of the anthrax pathogen; and for identification of chromosomal rearrangements in leukemia patients. The protein microchips can be adapted for further use in proteomics. Bacterial and yeast cells were also immobilized in the gel, maintaining their viability, which open a wide potential for creation biosensors on the basis of microchips.

  4. XPS and NEXAFS studies of VUV/O₃-treated aromatic polyurea and its application to microchip electrophoresis.

    PubMed

    Shinohara, H; Nakahara, A; Kitagawa, F; Takahashi, Y; Otsuka, K; Shoji, S; Ohara, O; Mizuno, J

    2011-12-01

    In this study, the authors performed X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure (NEXAFS) studies of vacuum ultraviolet (VUV)/O₃-treated aromatic polyurea films to investigate their treatment effects. XPS and NEXAFS spectra indicate that the benzene ring was cleaved after treatment and that carboxyl, hydroxyl, ketone and aldehyde groups were formed at the cleaved sites. The VUV/O₃-treated polyurea film was applied to a polymethylmethacrylate (PMMA) microchip for microchip electrophoresis (MCE) of bovine serum albumin (BSA). Fast electro-osmotic mobility of 4.6×10(-4) cm²/V/s as well as reduction of the BSA adhesion was achieved. This functional surface is useful for high-speed MCE analysis.

  5. Photopatterning of Hydrogel Microarrays in Closed Microchips.

    PubMed

    Gumuscu, Burcu; Bomer, Johan G; van den Berg, Albert; Eijkel, Jan C T

    2015-12-14

    To date, optical lithography has been extensively used for in situ patterning of hydrogel structures in a scale range from hundreds of microns to a few millimeters. The two main limitations which prevent smaller feature sizes of hydrogel structures are (1) the upper glass layer of a microchip maintains a large spacing (typically 525 μm) between the photomask and hydrogel precursor, leading to diffraction of UV light at the edges of mask patterns, (2) diffusion of free radicals and monomers results in irregular polymerization near the illumination interface. In this work, we present a simple approach to enable the use of optical lithography to fabricate hydrogel arrays with a minimum feature size of 4 μm inside closed microchips. To achieve this, we combined two different techniques. First, the upper glass layer of the microchip was thinned by mechanical polishing to reduce the spacing between the photomask and hydrogel precursor, and thereby the diffraction of UV light at the edges of mask patterns. The polishing process reduces the upper layer thickness from ∼525 to ∼100 μm, and the mean surface roughness from 20 to 3 nm. Second, we developed an intermittent illumination technique consisting of short illumination periods followed by relatively longer dark periods, which decrease the diffusion of monomers. Combination of these two methods allows for fabrication of 0.4 × 10(6) sub-10 μm sized hydrogel patterns over large areas (cm(2)) with high reproducibility (∼98.5% patterning success). The patterning method is tested with two different types of photopolymerizing hydrogels: polyacrylamide and polyethylene glycol diacrylate. This method enables in situ fabrication of well-defined hydrogel patterns and presents a simple approach to fabricate 3-D hydrogel matrices for biomolecule separation, biosensing, tissue engineering, and immobilized protein microarray applications.

  6. Single-frequency microchip Nd lasers.

    PubMed

    Zayhowski, J J; Mooradian, A

    1989-01-01

    Optically pumped, single-frequency, Nd-doped, solid-state lasers have been constructed using flat-flat cavities, which were diced from large dielectrically coated wafers of various crystals. For example, a Nd:YAG laser with a cavity length of 730 microm has operated at room temperature in a single longitudinal mode from a threshold of less than 1 mW to greater than 40 times the threshold. Theslope efficiency was greater than 30%. Heterodyne measurements showed an instrument-limited linewidth of 5 kHz. The microchip lasers demonstrate ways to reduce greatly the cost and complexity offabricating small lasers and electro-optic devices.

  7. Non-destructive ion trap mass spectrometer and method

    DOEpatents

    Frankevich, Vladimir E.; Soni, Manish H.; Nappi, Mario; Santini, Robert E.; Amy, Jonathan W.; Cooks, Robert G.

    1997-01-01

    The invention relates to an ion trap mass spectrometer of the type having an ion trapping volume defined by spaced end caps and a ring electrode. The ion trap includes a small sensing electrode which senses characteristic motion of ions trapped in said trapping volume and provides an image current. Ions are excited into characteristic motion by application of an excitation pulse to the trapped ions. The invention also relates to a method of operating such an ion trap.

  8. A graphene-modified cellulose paper microchip for HIV detection

    NASA Astrophysics Data System (ADS)

    Safavieh, Mohammadali; Khetani, Sultan; Kaul, Vivasvat; Kuritzkes, Daniel R.; Shafiee, Hadi

    2015-05-01

    Rapid and inexpensive virus detection and quantification at the point-of-care is of paramount importance for HIV management in resource-limited settings. Here, we report on an easy-to-fabricate, cellulose paper-based microchip with printed graphene-modified electrodes for rapid detection of HIV-1 through electrical sensing. We evaluated the effect of electrode material and geometry on the performance of the microchip to detect serially diluted, electrically conductive samples. We evaluated the optimized microchip with HIVspiked samples.

  9. Contactless conductivity detector for microchip capillary electrophoresis.

    PubMed

    Pumera, Martin; Wang, Joseph; Opekar, Frantisek; Jelínek, Ivan; Feldman, Jason; Löwe, Holger; Hardt, Steffen

    2002-05-01

    A microfabricated electrophoresis chip with an integrated contactless conductivity detection system is described. The new contactless conductivity microchip detector is based on placing two planar sensing aluminum film electrodes on the outer side of a poly(methyl methacrylate) (PMMA) microchip (without contacting the solution) and measuring the impedance of the solution in the separation channel. The contactless route obviates problems (e.g., fouling, unwanted reactions) associated with the electrode-solution contact, offers isolation of the detection system from high separation fields, does not compromise the separation efficiency, and greatly simplifies the detector fabrication. Relevant experimental variables, such as the frequency and amplitude of the applied ac voltage or the separation voltage, were examined and optimized. The detector performance was illustrated by the separation of potassium, sodium, barium, and lithium cations and the chloride, sulfate, fluoride, acetate, and phosphate anions. The response was linear (over the 20 microM-7 mM range) and reproducible (RSD = 3.4-4.9%; n = 10), with detection limits of 2.8 and 6.4 microM (for potassium and chloride, respectively). The advantages associated with the contactless conductivity detection, along with the low cost of the integrated PMMA chip/detection system, should enhance the power and scope of microfluidic analytical devices.

  10. Contactless conductivity detector for microchip capillary electrophoresis

    NASA Technical Reports Server (NTRS)

    Pumera, Martin; Wang, Joseph; Opekar, Frantisek; Jelinek, Ivan; Feldman, Jason; Lowe, Holger; Hardt, Steffen; Svehla, D. (Principal Investigator)

    2002-01-01

    A microfabricated electrophoresis chip with an integrated contactless conductivity detection system is described. The new contactless conductivity microchip detector is based on placing two planar sensing aluminum film electrodes on the outer side of a poly(methyl methacrylate) (PMMA) microchip (without contacting the solution) and measuring the impedance of the solution in the separation channel. The contactless route obviates problems (e.g., fouling, unwanted reactions) associated with the electrode-solution contact, offers isolation of the detection system from high separation fields, does not compromise the separation efficiency, and greatly simplifies the detector fabrication. Relevant experimental variables, such as the frequency and amplitude of the applied ac voltage or the separation voltage, were examined and optimized. The detector performance was illustrated by the separation of potassium, sodium, barium, and lithium cations and the chloride, sulfate, fluoride, acetate, and phosphate anions. The response was linear (over the 20 microM-7 mM range) and reproducible (RSD = 3.4-4.9%; n = 10), with detection limits of 2.8 and 6.4 microM (for potassium and chloride, respectively). The advantages associated with the contactless conductivity detection, along with the low cost of the integrated PMMA chip/detection system, should enhance the power and scope of microfluidic analytical devices.

  11. Photochemistry of 1,4-Dihydropyridine Derivatives: Diradical Formation, Delocalization and Trapping as a Route to Novel Tricyclic and Tetracyclic Nitrogen Heterocyclic Ring Systems.

    PubMed

    Al-Jalal, Nader A; Ibrahim, Yehia A; Al-Awadi, Nouria A; Ibrahim, Maher R; Sayed, Osama M

    2016-06-30

    Irradiation of an acetonitrile solution of 4-aryl-3,5-dibenzoyl-1,4-dihydropyridine derivatives 1a-c and maleimides 2a-c using medium pressure Hg-arc lamp (λ > 290) nm afforded three different cycloadducts 4, 5, 6 in addition to the oxidation products 3. These results indicate that compounds 1a-c undergoes intermolecular cycloaddition reaction through three biradical intermediates and behave photochemically different than those reported previously for the analogous 3,5-diacetyl and 3,5-dicarboxylic acid derivatives. The present work also offers simple access to novel tricyclic and tetracyclic nitrogen heterocyclic ring systems of potential biological and synthetic applications. The structure of the photoproducts was established spectroscopically and by single crystal X-ray crystallography.

  12. A hydrodynamic microchip for formation of continuous cell chains

    NASA Astrophysics Data System (ADS)

    Khoshmanesh, Khashayar; Zhang, Wei; Tang, Shi-Yang; Nasabi, Mahyar; Soffe, Rebecca; Tovar-Lopez, Francisco J.; Rajadas, Jayakumar; Mitchell, Arnan

    2014-05-01

    Here, we demonstrate the unique features of a hydrodynamic based microchip for creating continuous chains of model yeast cells. The system consists of a disk shaped microfluidic structure, containing narrow orifices that connect the main channel to an array of spoke channels. Negative pressure provided by a syringe pump draws fluid from the main channel through the narrow orifices. After cleaning process, a thin layer of water is left between the glass substrate and the polydimethylsiloxane microchip, enabling leakage beneath the channel walls. A mechanical clamp is used to adjust the operation of the microchip. Relaxing the clamp allows leakage of liquid beneath the walls in a controllable fashion, leading to formation of a long cell chain evenly distributed along the channel wall. The unique features of the microchip are demonstrated by creating long chains of yeast cells and model 15 μm polystyrene particles along the side wall and analysing the hydrogen peroxide induced death of patterned cells.

  13. Improvement of heat dissipation for polydimethylsiloxane microchip electrophoresis.

    PubMed

    Zhang, Yuan; Bao, Ning; Yu, Xiao-Dong; Xu, Jing-Juan; Chen, Hong-Yuan

    2004-11-19

    Effective removing of Joule heat in polymer-based microchip system is an important factor for high efficient separation because of lower heat conductivity of polymers than silica or glass. In this paper, a new kind of polydimethylsiloxane (PDMS) microchip electrophoresis system integrated with a laser-induced fluorescence detector has been successfully constructed on the basis of a commercial heat sink for computer CPU (central processor unit). Experimental results on separation current using high concentration running buffers demonstrated that heat dissipation of PDMS/PDMS microchip system was significantly improved. Furthermore, with this integrated system, theoretical plate number of fluorescein using 100 mM phosphate-buffered saline + 1 mM sodium dodecyl sulfate as running buffer was determined to be 2750 (for 2.5-cm separation channel, corresponding to 110,000/m). This high separation efficiency demonstrated that such heat sink-based polymer microchip system could be effectively applied for high-concentration buffers.

  14. Apparatus for Precise Indium-Bump Bonding of Microchips

    NASA Technical Reports Server (NTRS)

    Wild, Larry; Mulder, Jerry; Alvarado, Nicholas

    2005-01-01

    An improved apparatus has been designed and built for use in precise positioning and pressing of a microchip onto a substrate (which could, optionally, be another microchip) for the purpose of indium-bump bonding. The apparatus (see figure) includes the following: A stereomicroscope, A stage for precise positioning of the microchip in rotation angle (theta) about the nominally vertical pressing axis and in translation along two nominally horizontal coordinate axes (x and y), and An actuator system that causes a bonding tip to press the microchip against the substrate with a precisely controlled force. In operation, the microscope and the stage are used to position the microchip under the bonding tip and to align the indium bumps on the chip and the substrate, then the actuator system is used to apply a prescribed bonding force for a prescribed time. The improved apparatus supplants a partly similar prior apparatus that operated with less precision and repeatability, producing inconsistent and unreliable bonds. Results of the use of the prior apparatus included broken microchips, uneven bonds, and bonds characterized, variously, by overcompression or undercompression. In that apparatus, the bonding force was generated and controlled by use of a micrometer head positioned over the center of a spring-loaded scale, and the force was applied to the microchip via the scale, which was equipped for digital readout of the force. The inconsistency of results was attributed to the following causes: It was not possible to control the bonding force with sufficient precision or repeatability. Particularly troublesome was the inability to control the force at levels less than the weight of 150 g. Excessive compliance in the spring-loaded scale, combined with deviations from parallelarity of the substrate and bonding-tip surfaces, gave rise to nonuniformity in the pressure applied to the microchip, thereby generating excessive stresses and deformations in the microchip. In the

  15. Effect of Compressive Stresses on Leakage Currents in Microchip Tantalum Capacitors

    NASA Technical Reports Server (NTRS)

    Teverovsky, Alexander

    2012-01-01

    Microchip tantalum capacitors are manufactured using new technologies that allow for production of small size capacitors (down to EIA case size 0402) with volumetric efficiency much greater than for regular chip capacitors. Due to a small size of the parts and leadless design they might be more sensitive to mechanical stresses that develop after soldering onto printed wiring boards (PWB) compared to standard chip capacitors. In this work, the effect of compressive stresses on leakage currents in capacitors has been investigated in the range of stresses up to 200 MPa. Significant, up to three orders of magnitude, variations of currents were observed after the stress exceeds a certain critical level that varied from 10 MPa to 180 MPa for capacitors used in this study. A stress-induced generation of electron traps in tantalum pentoxide dielectric is suggested to explain reversible variations of leakage currents in tantalum capacitors. Thermo-mechanical characteristics of microchip capacitors have been studied to estimate the level of stresses caused by assembly onto PWB and assess the risk of stress-related degradation and failures. Keywords: tantalum capacitors, leakage current, soldering, reliability, mechanical stress.

  16. A Microchip for Integrated Single-Cell Gene Expression Profiling and Genotoxicity Detection

    PubMed Central

    Dong, Hui; Sun, Hao

    2016-01-01

    Microfluidics-based single-cell study is an emerging approach in personalized treatment or precision medicine studies. Single-cell gene expression holds a potential to provide treatment selections with maximized efficacy to help cancer patients based on a genetic understanding of their disease. This work presents a multi-layer microchip for single-cell multiplexed gene expression profiling and genotoxicity detection. Treated by three drug reagents (i.e., methyl methanesulfonate, docetaxel and colchicine) with varied concentrations and time lengths, individual human cancer cells (MDA-MB-231) are lysed on-chip, and the released mRNA templates are captured and reversely transcribed into single strand DNA. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH), cyclin-dependent kinase inhibitor 1A (CDKN1A), and aurora kinase A (AURKA) genes from single cells are amplified and real-time quantified through multiplex polymerase chain reaction. The microchip is capable of integrating all steps of single-cell multiplexed gene expression profiling, and providing precision detection of drug induced genotoxic stress. Throughput has been set to be 18, and can be further increased following the same approach. Numerical simulation of on-chip single cell trapping and heat transfer has been employed to evaluate the chip design and operation. PMID:27649175

  17. Microchip-Embedded Capacitors for Implantable Neural Stimulators

    NASA Astrophysics Data System (ADS)

    Auciello, Orlando

    Miniaturization of microchips for implantation in the human body (e.g., microchip for the artificial retina to restore sight to people blinded by retina photoreceptors degeneration) requires the integration of high-capacitance (≥ 10 μF) energy-storage capacitors into the microchip. These capacitors would be based on high-dielectric constant layers, preferably made of materials that are bioinert (not affected by human body fluids) and are biocompatible (do not elicit adverse reactions in the human body). This chapter focuses on reviewing the work being done at Argonne National Laboratory (Materials Science Division and Center for Nanoscale Materials) to develop high-capacitance microchip-embedded capacitors based on novel high-K dielectric layers (TiAlOx or TiO2/Al2O3 superlattices). The microchip-embedded capacitor provides energy storage and electromagnetic signal coupling needed for neural stimulations. Advances in neural prostheses such as artificial retinas and cochlear implants require miniaturization of device size to minimize tissue damage and improve device/tissue interfaces in the human body. Therefore, development of microchip-embedded capacitors is critical to achieve full-implantable biomedical device miniaturization.

  18. Cathemerality in wild ring-tailed lemurs (Lemur catta) in the spiny forest of Tsimanampetsotsa National Park: camera trap data and preliminary behavioral observations.

    PubMed

    LaFleur, Marni; Sauther, Michelle; Cuozzo, Frank; Yamashita, Nayuta; Jacky Youssouf, Ibrahim Antho; Bender, Richard

    2014-04-01

    Cathemerality consists of discrete periods of activity during both the day and night. Though uncommon within Primates, cathemerality is prevalent in some lemur genera, such as Eulemur, Hapalemur, and Prolemur. Several researchers have also reported nighttime activity in Lemur catta, yet these lemurs are generally considered "strictly diurnal". We used behavioral observations and camera traps to examine cathemerality of L. catta at the Tsimanampetsotsa National Park, Madagascar. Nighttime activity occurred throughout the study period (September 2010-April 2011), and correlated with warm overnight temperatures but not daytime temperatures. Animals spent 25% of their daytime active behaviors on the ground, but appeared to avoid the ground at night, with only 5% of their time on the ground. Furthermore, at night, animals spent the majority of their active time feeding (53% nighttime, 43% daytime). These findings imply that both thermoregulation and diet play a role in the adaptive significance of cathemerality. Additionally, predator avoidance may have influenced cathemerality here, in that L. catta may limit nighttime activity as a result of predation threat by forest cats (Felis sp.) or fossa (Cryptoprocta ferox). Further data are needed on cathemeral lemurs generally, but particularly in L. catta if we are to fully understand the evolutionary mechanisms of cathemerality in the Lemuridae.

  19. Asymmetric ion trap

    DOEpatents

    Barlow, S.E.; Alexander, M.L.; Follansbee, J.C.

    1997-12-02

    An ion trap having two end cap electrodes disposed asymmetrically about a center of a ring electrode is disclosed. The inner surface of the end cap electrodes are conformed to an asymmetric pair of equipotential lines of the harmonic formed by the application of voltages to the electrodes. The asymmetry of the end cap electrodes allows ejection of charged species through the closer of the two electrodes which in turn allows for simultaneously detecting anions and cations expelled from the ion trap through the use of two detectors charged with opposite polarity. 4 figs.

  20. Asymmetric ion trap

    DOEpatents

    Barlow, Stephan E.; Alexander, Michael L.; Follansbee, James C.

    1997-01-01

    An ion trap having two end cap electrodes disposed asymmetrically about a center of a ring electrode. The inner surface of the end cap electrodes are conformed to an asymmetric pair of equipotential lines of the harmonic formed by the application of voltages to the electrodes. The asymmetry of the end cap electrodes allows ejection of charged species through the closer of the two electrodes which in turn allows for simultaneously detecting anions and cations expelled from the ion trap through the use of two detectors charged with opposite polarity.

  1. Subsecond chiral separations on a microchip.

    PubMed

    Piehl, Natalia; Ludwig, Martin; Belder, Detlev

    2004-11-01

    Fast chiral separation of DNS-amino acids could be realized using microchip electrophoresis with fluorescence detection. For this purpose, highly sulfated cyclodextrins (HS-gamma-CD) were used as chiral selectors enabling high selectivity. Even subsecond separation of DNS-tryptophan, DNS-norleucine, DNS-phenylalanine, DNS-methionine, and DNS-aspartic acid could be achieved. Baseline separation could be accomplished within 720 ms, which is the fastest separation of enantiomers reported to date. A more complex mixture consisting of three chiral DNS-amino acids could be separated within 3.3 s utilizing a separation length of only 7 mm and an electrical field strength of 2012 V/cm.

  2. Etching of glass microchips with supercritical water.

    PubMed

    Karásek, Pavel; Grym, Jakub; Roth, Michal; Planeta, Josef; Foret, František

    2015-01-07

    A novel method of etching channels in glass microchips with the most tunable solvent, water, was tested as an alternative to common hydrogen fluoride-containing etchants. The etching properties of water strongly depend on temperature and pressure, especially in the vicinity of the water critical point. The chips were etched at the subcritical, supercritical and critical temperature of water, and the resulting channel shape, width, depth and surface morphology were studied by scanning electron microscopy and 3D laser profilometry. Channels etched with the hot water were compared with the chips etched with standard hydrogen fluoride-containing solution. Depending on the water pressure and temperature, the silicate dissolved from the glass could be re-deposited on the channel surface. This interesting phenomenon is described together with the conditions necessary for its utilization. The results illustrate the versatility of pure water as a glass etching and surface morphing agent.

  3. A high repetition rate passively Q-switched microchip laser for controllable transverse laser modes

    NASA Astrophysics Data System (ADS)

    Dong, Jun; Bai, Sheng-Chuang; Liu, Sheng-Hui; Ueda, Ken-Ichi; Kaminskii, Alexander A.

    2016-05-01

    A Cr4+:YAG passively Q-switched Nd:YVO4 microchip laser for versatile controllable transverse laser modes has been demonstrated by adjusting the position of the Nd:YVO4 crystal along the tilted pump beam direction. The pump beam diameter-dependent asymmetric saturated inversion population inside the Nd:YVO4 crystal governs the oscillation of various Laguerre-Gaussian, Ince-Gaussian and Hermite-Gaussian modes. Controllable transverse laser modes with repetition rates over 25 kHz and up to 183 kHz, depending on the position of the Nd:YVO4 crystal, have been achieved. The controllable transverse laser beams with a nanosecond pulse width and peak power over hundreds of watts have been obtained for potential applications in optical trapping and quantum computation.

  4. A microchip integrating cell array positioning with in situ single-cell impedance measurement.

    PubMed

    Guo, Xiaoliang; Zhu, Rong; Zong, Xianli

    2015-10-07

    This paper presents a novel microarray chip integrating cell positioning with in situ, real-time and long-time impedance measurement on a single cell. The microchip integrates a plurality of quadrupole-electrode units (termed positioning electrodes) patterned into an array with pairs of planar electrodes (termed measuring electrodes) located at the centers of each quadrupole-electrode unit. The positioning electrodes are utilized to trap and position living cells onto the measuring electrodes based on negative dielectrophoresis (nDEP), while the measuring electrodes are used to measure impedances of the trapped single cells. Each measuring electrode has a small footprint area of 7 × 7 μm(2) to ensure inhabiting only one single cell on it. However, the electrode with a small surface area has a low double-layer capacitance when it is immersed in a liquid solution, thus generating a large double-layer impedance, which reduces the sensitivity for impedance measurement on the single cell. To enlarge the effective surface areas of the measuring electrodes, a novel surface-modification process is proposed to controllably construct gold nanostructures on the surfaces of the measuring electrodes while the positioning electrodes are unstained. The double layer capacitances of the modified electrodes are increased by about one order after surface-modification. The developed microchip is used to monitor the adhering behavior of a single HeLa cell by measuring its impedance spectra in real time. The measured impedance is analyzed and used to extract cellular electrical parameters, which demonstrated that the cell compresses the electrical double layer in the process of adherence and adheres onto the measuring electrodes after 4-5 hours.

  5. Measuring and manipulating the temperature of cold molecules trapped on a chip

    NASA Astrophysics Data System (ADS)

    Marx, S.; Adu Smith, D.; Insero, G.; Meek, S. A.; Sartakov, B. G.; Meijer, G.; Santambrogio, G.

    2015-12-01

    Following Marx et al. [Phys. Rev. Lett. 111, 243007 (2013), 10.1103/PhysRevLett.111.243007], we discuss the measurement and manipulation of the temperature of cold CO molecules in a microchip environment. In particular, we present a model to explain the observed and calculated velocity distributions. We also show that a translational temperature can be extracted directly from the measurements. Finally, we discuss the conditions needed for an effective adiabatic cooling of the molecular ensemble trapped on the microchip.

  6. CE microchips: an opened gate to food analysis.

    PubMed

    Escarpa, Alberto; González, María Cristina; Crevillén, Agustín González; Blasco, Antonio Javier

    2007-03-01

    CE microchips are the first generation of micrototal analysis systems (-TAS) emerging in the miniaturization scene of food analysis. CE microchips for food analysis are fabricated in both glass and polymer materials, such as PDMS and poly(methyl methacrylate) (PMMA), and use simple layouts of simple and double T crosses. Nowadays, the detection route preferred is electrochemical in both, amperometry and conductivity modes, using end-channel and contactless configurations, respectively. Food applications using CE microchips are now emerging since food samples present complex matrices, the selectivity being a very important challenge because the total integration of analytical steps into microchip format is very difficult. As a consequence, the first contributions that have recently appeared in the relevant literature are based primarily on fast separations of analytes of high food significance. These protocols are combined with different strategies to achieve selectivity using a suitable nonextensive sample preparation and/or strategically choosing detection routes. Polyphenolic compounds, amino acids, preservatives, and organic and inorganic ions have been studied using CE microchips. Thus, new and exciting future expectations arise in the domain of food analysis. However, several drawbacks could easily be found and assumed within the miniaturization map.

  7. Effect of aspect ratio on chemical reactions on microchip.

    PubMed

    Shimizu, Takahiro; Masaki, Hiroyuki; Korenaga, Takashi

    2006-01-01

    Parallel two-phase laminar flow, which is formed when two solutions flow in microchannels, has been developed and has advanced unique research in the area of microchip analysis. In two-phase laminar flow, channel size has a significant effect on the efficiency of chemical reactions. However, the sizes of microchannels vary greatly in many studies. In this paper, we report on the effect of microchannel size on chemical reactions on a microchip. Aspect ratio is defined as the ratio of depth to width of a microchannel. Five microchips with different aspect ratios (from 0.50 to 2.00) were fabricated by mechanical machining. The reaction of nitrous acid and Saltzman reagent was carried out on these microchips and the absorbance was measured on-line in a capillary tube, which was attached to the outlet on the microchip. The results showed that the color reaction occurred more efficiently as the aspect ratio increased. This result is expected to be useful when determining the size of microchannels.

  8. Trapping waves in Earth's plasmasphere

    NASA Astrophysics Data System (ADS)

    Betz, Eric O.

    2014-12-01

    Earth's magnetic field traps donut-shaped bands of radiation in a belt around the planet that react to solar eruptions by growing and shrinking. The Van Allen belts consist of two rings filled with particles from the solar wind and cosmic rays. Within the outer ring of the Van Allen belt sits the plasmasphere, which is the innermost part of the planet's magnetic field and home to low-energy charged particles.

  9. Cryogenic Tm:YAP microchip laser

    NASA Astrophysics Data System (ADS)

    Hubka, Zbyněk.; Å ulc, Jan; Jelínková, Helena; Nejezchleb, Karel; Å koda, Václav

    2016-04-01

    The spectral characteristics of laser active media, and thus those of the laser output, are temperature dependent. Specifically, in almost every crystal host, cooling to low temperatures leads to better heat removal, a higher efficiency and output power, and a reduced lasing threshold. Tm-ion doped lasers have an emission wavelength around 2 μm and are important in medicine for soft tissue cutting and hemostasis, as well as in LIDAR or atmosphere sensing technology. This paper presents the performance-temperature dependency of a 4 at. % doped Tm:YAP microchip. During the experiment the Tm:YAP crystal was placed inside an evacuated liquid nitrogen cryostat on a cooling finger. As its temperature was varied from 80 K to 340 K, changes were observed in the absorption spectrum, ranging from 750 nm to 2000 nm and in the fluorescence spectrum from 1600 nm to 2050 nm. Fluorescence lifetime was seen to rise and fall with decreasing temperature. The laser was pumped by a 792 nm laser diode and at 80 K the maximum output peak power of the laser was 4.6 W with 23 % slope efficiency and 0.6 W threshold, compared to 2.4 W output peak power, 13 % slope efficiency and 3.3 W threshold when at 340 K. The laser emission wavelength changed from 1883 nm to 1993 nm for 80 K and 300 K, respectively.

  10. Serial dilution microchip for cytotoxicity test

    NASA Astrophysics Data System (ADS)

    Bang, Hyunwoo; Lim, Sun Hee; Lee, Young Kyung; Chung, Seok; Chung, Chanil; Han, Dong-Chul; Chang, Jun Keun

    2004-08-01

    Today's pharmaceutical industry is facing challenges resulting from the vast increases in sample numbers produced by high-throughput screening (HTS). In addition, the bottlenecks created by increased demand for cytotoxicity testing (required to assess compound safety) are becoming a serious problem. We have developed a polymer PDMS (polydimethylsiloxane) based microfluidic device that can perform a cytotoxicity test in a rapid and reproducible manner. The concept that the device includes is well adjustable to automated robots in huge HTS systems, so we can think of it as a potential dilution and delivery module. Cytotoxicity testing is all about the dilution and dispensing of a drug sample. Previously, we made a PDMS based microfluidic device which automatically and precisely diluted drugs with a buffer solution with serially increasing concentrations. This time, the serially diluted drug solution was directly delivered to 96 well plates for cytotoxicity testing. Cytotoxic paclitaxel solution with 2% RPMI 1640 has been used while carrying out cancerous cell based cytotoxicity tests. We believe that this rapid and robust use of the PDMS microchip will overcome the growing problem in cytotoxicity testing for HTS.

  11. Rapid bonding of Pyrex glass microchips.

    PubMed

    Akiyama, Yoshitake; Morishima, Keisuke; Kogi, Atsuna; Kikutani, Yoshikuni; Tokeshi, Manabu; Kitamori, Takehiko

    2007-03-01

    A newly developed vacuum hot press system has been specially designed for the thermal bonding of glass substrates in the fabrication process of Pyrex glass microchemical chips. This system includes a vacuum chamber equipped with a high-pressure piston cylinder and carbon plate heaters. A temperature of up to 900 degrees C and a force of as much as 9800 N could be applied to the substrates in a vacuum atmosphere. The Pyrex substrates bonded with this system under different temperatures, pressures, and heating times were evaluated by tensile strength tests, by measurements of thickness, and by observations of the cross-sectional shapes of the microchannels. The optimal bonding conditions of the Pyrex glass substrates were 570 degrees C for 10 min under 4.7 N/mm(2) of applied pressure. Whereas more than 16 h is required for thermal bonding with a conventional furnace, the new system could complete the whole bonding processes within just 79 min, including heating and cooling periods. Such improvements should considerably enhance the production rate of Pyrex glass microchemical chips. Whereas flat and dust-free surfaces are required for conventional thermal bonding, especially without long and repeated heating periods, our hot press system could press a fine dust into glass substrates so that even the areas around the dust were bonded. Using this capability, we were able to successfully integrate Pt/Ti thin film electrodes into a Pyrex glass microchip.

  12. Further improvement of hydrostatic pressure sample injection for microchip electrophoresis.

    PubMed

    Luo, Yong; Zhang, Qingquan; Qin, Jianhua; Lin, Bingcheng

    2007-12-01

    Hydrostatic pressure sample injection method is able to minimize the number of electrodes needed for a microchip electrophoresis process; however, it neither can be applied for electrophoretic DNA sizing, nor can be implemented on the widely used single-cross microchip. This paper presents an injector design that makes the hydrostatic pressure sample injection method suitable for DNA sizing. By introducing an assistant channel into the normal double-cross injector, a rugged DNA sample plug suitable for sizing can be successfully formed within the cross area during the sample loading. This paper also demonstrates that the hydrostatic pressure sample injection can be performed in the single-cross microchip by controlling the radial position of the detection point in the separation channel. Rhodamine 123 and its derivative as model sample were successfully separated.

  13. Analysis of anions in ambient aerosols by microchip capillary electrophoresis.

    PubMed

    Liu, Yan; MacDonald, David A; Yu, Xiao-Ying; Hering, Susanne V; Collett, Jeffrey L; Henry, Charles S

    2006-11-01

    We describe a microchip capillary electrophoresis method for the analysis of nitrate and sulfate in ambient aerosols. Investigating the chemical composition of ambient aerosol particles is essential for understanding their sources and effects. Significant progress has been made towards developing mass spectrometry-based instrumentation for rapid qualitative analysis of aerosols. Alternative methods for rapid quantification of selected high abundance compounds are needed to augment the capacity for widespread routine analysis. Such methods could provide much higher temporal and spatial resolution than can be achieved currently. Inorganic anions comprise a large percentage of particulate mass, with nitrate and sulfate among the most abundant species. While ion chromatography has proven very useful for analyzing extracts of time-integrated ambient aerosol samples collected on filters and for semi-continuous, on-line particle composition measurements, there is a growing need for development of new compact, inexpensive approaches to routine on-line aerosol ion analysis for deployment in spatially dense, atmospheric measurement networks. Microchip capillary electrophoresis provides the necessary speed and portability to address this need. In this report, on-column contact conductivity detection is used with hydrodynamic injection to create a simple microchip instrument for analysis of nitrate and sulfate. On-column contact conductivity detection was achieved using a Pd decoupler placed upstream from the working electrodes. Microchips containing two Au or Pd working electrodes showed a good linear range (5-500 microM) and low limits-of-detection for sulfate and nitrate, with Au providing the lowest detection limits (1 microM) for both ions. The completed microchip system was used to analyze ambient aerosol filter samples. Nitrate and sulfate concentrations measured by the microchip matched the concentrations measured by ion chromatography.

  14. A circular ferrofluid driven microchip for rapid polymerase chain reaction.

    PubMed

    Sun, Y; Kwok, Y C; Nguyen, N T

    2007-08-01

    In the past few years, much attention has been paid to the development of miniaturized polymerase chain reaction (PCR) devices. After a continuous flow (CF) PCR chip was introduced, several CFPCR systems employing various pumping mechanisms were reported. However, the use of pumps increases cost and imposes a high requirement on microchip bonding integrity due to the application of high pressure. Other significant limitations of CFPCR devices include the large footprint of the microchip and the fixed cycle number which is dictated by the channel layout. In this paper, we present a novel circular close-loop ferrofluid driven microchip for rapid PCR. A small ferrofluid plug, containing sub-domain magnetic particles in a liquid carrier, is driven by an external magnet along the circular microchannel, which in turn propels the PCR mixture through three temperature zones. Amplification of a 500 bp lambda DNA fragment has been demonstrated on the polymethyl methacrylate (PMMA) PCR microchip fabricated by CO(2) laser ablation and bonded by a low pressure, high temperature technique. Successful PCR was achieved in less than 4 min. Effects of cycle number and cycle time on PCR products were investigated. Using a magnet as the actuator eliminates the need for expensive pumps and provides advantages of low cost, small power consumption, low requirement on bonding strength and flexible number of PCR cycles. Furthermore, the microchip has a much simpler design and smaller footprint compared to the rectangular serpentine CFPCR devices. To demonstrate its application in forensics, a 16-loci short tandem repeat (STR) sample was successfully amplified using the PCR microchip.

  15. COLD TRAPS

    DOEpatents

    Thompson, W.I.

    1958-09-30

    A cold trap is presented for removing a condensable component from a gas mixture by cooling. It consists of a shell, the exterior surface of which is chilled by a refrigerant, and conductive fins welded inside the shell to condense the gas, and distribute the condensate evenly throughout the length of the trap, so that the trap may function until it becomes completely filled with the condensed solid. The contents may then be removed as either a gas or as a liquid by heating the trap. This device has particuinr use as a means for removing uranium hexafluoride from the gaseous diffusion separation process during equipment breakdown and repair periods.

  16. Optical trapping

    PubMed Central

    Neuman, Keir C.; Block, Steven M.

    2006-01-01

    Since their invention just over 20 years ago, optical traps have emerged as a powerful tool with broad-reaching applications in biology and physics. Capabilities have evolved from simple manipulation to the application of calibrated forces on—and the measurement of nanometer-level displacements of—optically trapped objects. We review progress in the development of optical trapping apparatus, including instrument design considerations, position detection schemes and calibration techniques, with an emphasis on recent advances. We conclude with a brief summary of innovative optical trapping configurations and applications. PMID:16878180

  17. Analysis of proteins and peptides by electromigration methods in microchips.

    PubMed

    Štěpánová, Sille; Kašička, Václav

    2017-01-01

    This review presents the developments and applications of microchip electromigration methods in the separation and analysis of peptides and proteins in the period 2011-mid-2016. The developments in sample preparation and preconcentration, microchannel material, and surface treatment are described. Separations by various microchip electromigration methods (zone electrophoresis in free and sieving media, affinity electrophoresis, isotachophoresis, isoelectric focusing, electrokinetic chromatography, and electrochromatography) are demonstrated. Advances in detection methods are reported and novel applications in the areas of proteomics and peptidomics, quality control of peptide and protein pharmaceuticals, analysis of proteins and peptides in biomatrices, and determination of physicochemical parameters are shown.

  18. Protein self-interaction chromatography on a microchip.

    PubMed

    Deshpande, Kedar; Ahamed, Tangir; van der Wielen, Luuk A M; Horst, Joop H Ter; Jansens, Peter J; Ottens, Marcel

    2009-02-21

    This paper presents the development of a novel miniaturized experimental procedure for the measurement of protein-protein interactions through Self-Interaction Chromatography (SIC) on a microchip, without the use of chromatographic resins. SIC was recently demonstrated to be a relatively easy method to obtain quantitative thermodynamic information about protein-protein interactions, like the osmotic second virial coefficient B(22), which relates to protein phase behavior including protein crystallization. This successful miniaturization to microchip level of a measurement device for protein self-interaction data is a first key step to a complete microfluidic screening platform for the rational design of protein crystallizations, using substantially less expensive protein and experimentation time.

  19. Measurement of electroosmotic flow in capillary and microchip electrophoresis.

    PubMed

    Wang, Wei; Zhou, Fang; Zhao, Liang; Zhang, Jian-Rong; Zhu, Jun-Jie

    2007-11-02

    Microfluidics is the science and technology of systems that process or manipulate small amounts of fluids, using channels with dimensions of tens of micrometers. Electroosmotic flow (EOF) is an important characteristic of fluids in microchannels. In this paper, EOF generation, effects on separation and definition of EOF are introduced. And EOF measurement methods on capillary electrophoresis (CE) and microchip CE are systematically reviewed based on detection principle, hallmarks of EOF measurement methods are presented, the devices and signals are also schematically described. This paper offers researchers a guidance to obtain an estimate of EOF mobility in capillary and microchip electrophoresis.

  20. Kinetics of hybridization on surface oligonucleotide microchips: theory, experiment, and comparison with hybridization on gel-based microchips.

    PubMed

    Sorokin, N V; Chechetkin, V R; Pan'kov, S V; Somova, O G; Livshits, M A; Donnikov, M Y; Turygin, A Y; Barsky, V E; Zasedatelev, A S

    2006-08-01

    The optimal design of oligonucleotide microchips and efficient discrimination between perfect and mismatch duplexes strongly depend on the external transport of target DNA to the cells with immobilized probes as well as on respective association and dissociation rates at the duplex formation. In this paper we present the relevant theory for hybridization of DNA fragments with oligonucleotide probes immobilized in the cells on flat substrate. With minor modifications, our theory also is applicable to reaction-diffusion hybridization kinetics for the probes immobilized on the surface of microbeads immersed in hybridization solution. The main theoretical predictions are verified with control experiments. Besides that, we compared the characteristics of the surface and gel-based oligonucleotide microchips. The comparison was performed for the chips printed with the same pin robot, for the signals measured with the same devices and processed by the same technique, and for the same hybridization conditions. The sets of probe oligonucleotides and the concentrations of probes in respective solutions used for immobilization on each platform were identical as well. We found that, despite the slower hybridization kinetics, the fluorescence signals and mutation discrimination efficiency appeared to be higher for the gel-based microchips with respect to their surface counterparts even for the relatively short hybridization time about 0.5-1 hour. Both the divergence between signals for perfects and the difference in mutation discrimination efficiency for the counterpart platforms rapidly grow with incubation time. In particular, for hybridization during 3 h the signals for gel-based microchips surpassed their surface counterparts in 5-20 times, while the ratios of signals for perfect-mismatch pairs for gel microchips exceeded the corresponding ratios for surface microchips in 2-4 times. These effects may be attributed to the better immobilization efficiency and to the higher

  1. Trap induction and trapping in eight nematode-trapping fungi (Orbiliaceae) as affected by juvenile stage of Caenorhabditis elegans.

    PubMed

    Xie, Hongyan; Aminuzzaman, F M; Xu, Lingling; Lai, Yiling; Li, Feng; Liu, Xingzhong

    2010-06-01

    This study measured trap induction and trapping on agar disks as affected by juvenile stages (J1, J2, J3, and J4) of the nematode Caenorhabditis elegans and by species of nematode-trapping fungi. Eight species of nematode-trapping fungi belonging to the family Orbiliaceae and producing four kinds of traps were studied: adhesive network-forming Arthrobotrys oligospora, A. vermicola, and A. eudermata, constricting ring-forming Drechslerella brochopaga, and Dr. stenobrocha, adhesive column-forming Dactylellina cionopaga, and adhesive knob-forming Da. ellipsospora, and Da. drechsleri. The number of traps induced generally increased with increasing juvenile stages of C. elegans. The ability to capture the juveniles tended to be similar among isolates that produced the same kind of trap but differed among species that produced different kinds of traps. Trapping by Dr. stenobrocha and Da. cionopaga was correlated with trap number and with juvenile stage. A. oligospora and A. vermicola respectively captured more than 92 and 88% of the J1, J3, and J4 but captured a lower percentage of J2. The knob-producing isolates captured more younger than elder juveniles. Partial correlation analyses demonstrated that the trap induction of the most fungal species positively correlated with the juvenile size and motility, which was juvenile stage dependent. Overall, trap induction and trapping correlated with C. elegans juvenile stage (size and motility) in six species of trapping fungi.

  2. Fabrication of PMMA CE microchips by infrared-assisted polymerization.

    PubMed

    Chen, Yun; Duan, Haotian; Zhang, Luyan; Chen, Gang

    2008-12-01

    In this report, a method based on the infrared-assisted polymerization of methyl methacrylate has been developed for the rapid fabrication of PMMA CE microchips. Methyl methacrylate containing AIBN was allowed to prepolymerize in a water bath to form a fast-curing molding solution that was subsequently sandwiched between a silicon template and a piece of 1 mm-thick PMMA plate. The images of microchannels on the silicon template were precisely replicated into the synthesized PMMA substrates during the infrared-assisted polymerization of the molding solution. The polymerization could be completed within 50 min at 50 degrees C. The obtained channel plate was subsequently bonded to a piece of PMMA cover sheet to form a microchip with the aid of heat and pressure. The new fabrication approach obviates the need for special equipment and significantly simplifies the process of fabricating PMMA microchips. The attractive performance of the obtained PMMA microchips has been demonstrated in connection with contactless conductivity detection for the separation and detection of ionic species.

  3. Longevity of radiofrequency identification device microchips in citrus trees

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Long-term identification of individual plants in the field is an important part of many types of botanical and horticultural research. In a previous report, we described methods for using implanted radiofrequency (RFID) microchips to tag citrus trees for field research. This report provides an upd...

  4. Implantable microchip: the futuristic controlled drug delivery system.

    PubMed

    Sutradhar, Kumar Bishwajit; Sumi, Chandra Datta

    2016-01-01

    There is no doubt that controlled and pulsatile drug delivery system is an important challenge in medicine over the conventional drug delivery system in case of therapeutic efficacy. However, the conventional drug delivery systems often offer a limited by their inability to drug delivery which consists of systemic toxicity, narrow therapeutic window, complex dosing schedule for long term treatment etc. Therefore, there has been a search for the drug delivery system that exhibit broad enhancing activity for more drugs with less complication. More recently, some elegant study has noted that, a new type of micro-electrochemical system or MEMS-based drug delivery systems called microchip has been improved to overcome the problems related to conventional drug delivery. Moreover, micro-fabrication technology has enabled to develop the implantable controlled released microchip devices with improved drug administration and patient compliance. In this article, we have presented an overview of the investigations on the feasibility and application of microchip as an advanced drug delivery system. Commercial manufacturing materials and methods, related other research works and current advancement of the microchips for controlled drug delivery have also been summarized.

  5. Integrated Micro-Chip Amino Acid Chirality Detector for MOD

    NASA Technical Reports Server (NTRS)

    Glavin, D. P.; Bada, J. L.; Botta, O.; Kminek, G.; Grunthaner, F.; Mathies, R.

    2001-01-01

    Integration of a micro-chip capillary electrophoresis analyzer with a sublimation-based extraction technique, as used in the Mars Organic Detector (MOD), for the in-situ detection of amino acids and their enantiomers on solar system bodies. Additional information is contained in the original extended abstract.

  6. Apparatus and method for performing electrodynamic focusing on a microchip

    DOEpatents

    Ramsey, John Michael; Jacobson, Stephen C.

    1999-01-01

    A microchip device includes a focusing channel, in which an electric field strength established in the focusing channel is controlled relative to an electric field strength established in a material transport channel segment to spatially focus the material traversing the material transport channel segment.

  7. Apparatus and method for performing electrodynamic focusing on a microchip

    DOEpatents

    Ramsey, J.M.; Jacobson, S.C.

    1999-01-12

    A microchip device includes a focusing channel, in which an electric field strength established in the focusing channel is controlled relative to an electric field strength established in a material transport channel segment to spatially focus the material traversing the material transport channel segment. 22 figs.

  8. Comparing polyelectrolyte multilayer-coated PMMA microfluidic devices and glass microchips for electrophoretic separations.

    PubMed

    Currie, Christa A; Shim, Joon Sub; Lee, Se Hwan; Ahn, Chong; Limbach, Patrick A; Halsall, H Brian; Heineman, William R

    2009-12-01

    There is a continuing drive in microfluidics to transfer microchip systems from the more expensive glass microchips to cheaper polymer microchips. Here, we investigate using polyelectrolyte multilayers (PEM) as a coating system for PMMA microchips to improve their functionality. The multilayer system was prepared by layer-to-layer deposition of poly(diallyldimethylammonium) chloride and polystyrene sulfonate. Practical aspects of coating PMMA microchips were explored. The multilayer buildup process was monitored using EOF measurements, and the stability of the PEM was investigated. The performance of the PEM-PMMA microchip was compared with those of a standard glass microchip and a PEM-glass microchip in terms of EOF and separating two fluorescent dyes. Several key findings in the development of the multilayer coating procedure for PMMA chips are also presented. It was found that, with careful preparation, a PEM-PMMA microchip can be prepared that has properties comparable--and in some cases superior--to those of a standard glass microchip.

  9. Comparing polyelectrolyte multilayer - coated poly(methylmethacrylate) microfluidic devices and glass microchips for electrophoretic separations

    PubMed Central

    Currie, Christa A.; Shim, Joon Sub; Ahn, Chong; Limbach, Patrick A.; Halsall, H. Brian

    2010-01-01

    There is a continuing drive in microfluidics to transfer microchip systems from the more expensive glass microchips to cheaper polymer microchips. Here, we investigate using polyelectrolyte multilayers (PEM) as a coating system for poly (methylmethacrylate) (PMMA) microchips to improve their functionality. The multilayer system was prepared by layer-on-layer depositon of poly (diallydimethylammonium) chloride (PDAD) and polystyrene sulfonate (PSS). Practical aspects of coating PMMA microchips were explored. The multilayer buildup process was monitored using EOF measurements, and the stability of the PEM was investigated. The performance of the PEM-PMMA microchip was compared to those of a standard glass microchip and a PEM-glass microchip in terms of electroosmotic flow and separating two fluorescent dyes. Several key findings in the development of the multilayer coating procedure for PMMA chips are also presented. It was found that, with careful preparation, a PEM-PMMA microchip can be prepared that has properties comparable - and in some cases superior - to those of a standard glass microchip. PMID:20013912

  10. Density estimation using the trapping web design: A geometric analysis

    USGS Publications Warehouse

    Link, W.A.; Barker, R.J.

    1994-01-01

    Population densities for small mammal and arthropod populations can be estimated using capture frequencies for a web of traps. A conceptually simple geometric analysis that avoid the need to estimate a point on a density function is proposed. This analysis incorporates data from the outermost rings of traps, explaining large capture frequencies in these rings rather than truncating them from the analysis.

  11. Implantable micro-chip for controlled delivery of diclofenac sodium.

    PubMed

    Lee, Seung Ho; Park, Min; Park, Chun Gwon; Kim, Byung-Hwi; Lee, Jieun; Choi, SungYoon; Nam, So-rae; Park, Sung-Hye; Choy, Young Bin

    2014-12-28

    We prepared an implantable micro-chip enabled for controlled delivery of diclofenac sodium (DS). The micro-chip was made of poly(methyl methacrylate), where a pair of micro-channels and micro-wells was embedded to serve as a drug diffusion barrier and a reservoir, respectively. For this purpose, the micro-channel and micro-well were filled with a water-soluble polymer, polyethylene glycol and a fine powder of DS, respectively. To modulate the drug release profile, we varied both the cross-sectional area and length of the micro-channels. Thus, the average rate and onset time of drug release could be varied from 0.32%/day to 3.68%/day and from day 0.5 to day 8, respectively, as the cross-sectional area to length ratio (i.e., A/L) of the micro-channels increased from 0.0026 mm to 0.0280 mm. To achieve both almost immediate onset and zero-order release of DS, we also prepared a micro-chip embedded with multiple pairs of the micro-wells and the micro-channels of different dimensions. In this work, a single micro-chip equipped with the micro-channels with A/Ls of 0.0280 mm, 0.0217 mm and 0.0108 mm exhibited almost zero-order drug release for 31 days (R2>0.996) after the release onset on day 0.5. When the resulting micro-chip was implanted in living rats, the drug concentration in the blood could be maintained at 148 ng/ml-225 ng/ml for the first 23 days while showing good biocompatibility.

  12. Saturn's Rings

    NASA Astrophysics Data System (ADS)

    Cuzzi, J. N.

    2014-12-01

    The rings are changing before our eyes; structure varies on all timescales and unexpected things have been discovered. Many questions have been answered, but some answers remain elusive (see Cuzzi et al 2010 for a review). Here we highlight the major ring science progress over the mission to date, and describe new observations planned for Cassini's final three years. Ring Composition and particle sizes: The rings are nearly all water ice with no other ices - so why are they reddish? The C Ring and Cassini Division are "dirtier" than the more massive B and A Rings, as shown by near-IR and, recently, microwave observations. Particle sizes, from stellar and radio occultations, vary from place to place. Ring structure, micro and macro: numerous spiral density waves and ubiquitous "self-gravity wakes" reveal processes which fostered planet formation in the solar system and elsewhere. However, big puzzles remain regarding the main ring divisions, the C Ring plateau structures, and the B Ring irregular structure. Moonlets, inside and out, seen and unseen: Two gaps contain sizeable moonlets, but more gaps seem to contain none; even smaller embedded "propeller" objects wander, systematically or randomly, through the A ring. Rubble pile ringmoons just outside the rings may escaped from the rings, and the recently discovered "Peggy" may be trying this as we watch. Impact bombardment of the rings: Comet fragments set the rings to rippling on century-timescales, and boulders crash through hourly; meanwhile, the constant hail of infalling Kuiper belt material has a lower mass flux than previously thought. Origin and Age of the Rings: The ring mass and bombardment play key roles. The ring mass is well known everywhere but in the B Ring (where most of it is). New models suggest how tidal breakup of evolving moons may have formed massive ancient rings, of which the current ring is just a shadow. During its last three years, the Cassini tour profile will allow entirely new

  13. Ultra sensitive affinity chromatography on avidin-functionalized PMMA microchip for low abundant post-translational modified protein enrichment.

    PubMed

    Xia, Hui; Murray, Kermit; Soper, Steven; Feng, June

    2012-02-01

    Post-translational modifications (PTM) of proteins play essential roles in cellular physiology and disease. The identification of protein substrates and detection of modification site helps understand PTM-mediated regulation in essential biological pathways and functions in various diseases. However, PTM proteins are typically present only at trace levels, making them difficult to identify in mass spectrometry based proteomics. In this paper, we report a novel and sensitive affinity chromatography on the avidin-functionalized poly(methyl methacrylate) (PMMA) microchip for enrichment of nanogram (ng) amount of PTMs. The chemical modification of poly(methyl methacrylate) (PMMA) surfaces yield avidin-terminated PMMA surfaces after UV radiation and consecutive EDC mediated coupling (amide reaction). This functionalized PMMA micro-device was developed to identify and specifically trap biotinylated PTM proteins of low abundance from complex protein mixture. Here we selected carbonylated protein as a representative PTM to illustrate the wide application of this affinity microchip for any PTMs converted into a tractable tag after derivatization. The surface topography, surface functional group mapping and elemental composition changes after each modification step of the treatment process were systematically measured qualitatively and quantitatively by atomic force microscopy, X-ray photoelectron spectroscopy and fluorescence microscopy. Quantitative study of biotinlated carbonylated protein capture recovery and elution efficiency of the device was also studied. We also envision that this subproteome enrichment micro-device can be assembled with other lab-on-a-chip components for follow-up protein analysis.

  14. Vascular ring

    MedlinePlus

    ... with aberrant subclavian and left ligamentum ateriosus; Congenital heart defect - vascular ring; Birth defect heart - vascular ring ... accounts for less than 1% of all congenital heart problems. The condition occurs as often in males ...

  15. Neptune's rings

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This 591-second exposure of the rings of Neptune were taken with the clear filter by the Voyager 2 wide-angle camera. The two main rings are clearly visible and appear complete over the region imaged. Also visible in this image is the inner faint ring and the faint band which extends smoothly from the ring roughly halfway between the two bright rings. Both of these newly discovered rings are broad and much fainter than the two narrow rings. The bright glare is due to over-exposure of the crescent on Neptune. Numerous bright stars are evident in the background. Both bright rings have material throughout their entire orbit, and are therefore continuous. The Voyager Mission is conducted by JPL for NASA's Office of Space Science and Applications.

  16. Ultrasonic imaging using trapped energy mode Fresnel lens transducers

    NASA Technical Reports Server (NTRS)

    Das, P.; Talley, S.; Kraft, R.; Tiersten, H. F.; Mcdonald, J. F.

    1980-01-01

    Trapped-energy focusing transducers operating in the 2-5 MHz range have been fabricated by plating concentric rings of electrodes on a piezoelectric plate. The concentric ring structure acts as a Fresnel lens and can be used to obtain excellent lateral focusing of ultrasonic waves. The trapping is sufficiently strong to permit optimization of electrode spacings to suppress spurious virtual foci and ring sidelobes.

  17. Trapped antihydrogen

    NASA Astrophysics Data System (ADS)

    Butler, E.; Andresen, G. B.; Ashkezari, M. D.; Baquero-Ruiz, M.; Bertsche, W.; Bowe, P. D.; Cesar, C. L.; Chapman, S.; Charlton, M.; Deller, A.; Eriksson, S.; Fajans, J.; Friesen, T.; Fujiwara, M. C.; Gill, D. R.; Gutierrez, A.; Hangst, J. S.; Hardy, W. N.; Hayden, M. E.; Humphries, A. J.; Hydomako, R.; Jenkins, M. J.; Jonsell, S.; Jørgensen, L. V.; Kemp, S. L.; Kurchaninov, L.; Madsen, N.; Menary, S.; Nolan, P.; Olchanski, K.; Olin, A.; Povilus, A.; Pusa, P.; Rasmussen, C. Ø.; Robicheaux, F.; Sarid, E.; Seif el Nasr, S.; Silveira, D. M.; So, C.; Storey, J. W.; Thompson, R. I.; van der Werf, D. P.; Wurtele, J. S.; Yamazaki, Y.

    Precision spectroscopic comparison of hydrogen and antihydrogen holds the promise of a sensitive test of the Charge-Parity-Time theorem and matter-antimatter equivalence. The clearest path towards realising this goal is to hold a sample of antihydrogen in an atomic trap for interrogation by electromagnetic radiation. Achieving this poses a huge experimental challenge, as state-of-the-art magnetic-minimum atom traps have well depths of only ˜1 T (˜0.5 K for ground state antihydrogen atoms). The atoms annihilate on contact with matter and must be `born' inside the magnetic trap with low kinetic energies. At the ALPHA experiment, antihydrogen atoms are produced from antiprotons and positrons stored in the form of non-neutral plasmas, where the typical electrostatic potential energy per particle is on the order of electronvolts, more than 104 times the maximum trappable kinetic energy. In November 2010, ALPHA published the observation of 38 antiproton annihilations due to antihydrogen atoms that had been trapped for at least 172 ms and then released—the first instance of a purely antimatter atomic system confined for any length of time (Andresen et al., Nature 468:673, 2010). We present a description of the main components of the ALPHA traps and detectors that were key to realising this result. We discuss how the antihydrogen atoms were identified and how they were discriminated from the background processes. Since the results published in Andresen et al. (Nature 468:673, 2010), refinements in the antihydrogen production technique have allowed many more antihydrogen atoms to be trapped, and held for much longer times. We have identified antihydrogen atoms that have been trapped for at least 1,000 s in the apparatus (Andresen et al., Nature Physics 7:558, 2011). This is more than sufficient time to interrogate the atoms spectroscopically, as well as to ensure that they have relaxed to their ground state.

  18. Trapped antihydrogen

    NASA Astrophysics Data System (ADS)

    Butler, E.; Andresen, G. B.; Ashkezari, M. D.; Baquero-Ruiz, M.; Bertsche, W.; Bowe, P. D.; Cesar, C. L.; Chapman, S.; Charlton, M.; Deller, A.; Eriksson, S.; Fajans, J.; Friesen, T.; Fujiwara, M. C.; Gill, D. R.; Gutierrez, A.; Hangst, J. S.; Hardy, W. N.; Hayden, M. E.; Humphries, A. J.; Hydomako, R.; Jenkins, M. J.; Jonsell, S.; Jørgensen, L. V.; Kemp, S. L.; Kurchaninov, L.; Madsen, N.; Menary, S.; Nolan, P.; Olchanski, K.; Olin, A.; Povilus, A.; Pusa, P.; Rasmussen, C. Ø.; Robicheaux, F.; Sarid, E.; Seif el Nasr, S.; Silveira, D. M.; So, C.; Storey, J. W.; Thompson, R. I.; van der Werf, D. P.; Wurtele, J. S.; Yamazaki, Y.

    2012-12-01

    Precision spectroscopic comparison of hydrogen and antihydrogen holds the promise of a sensitive test of the Charge-Parity-Time theorem and matter-antimatter equivalence. The clearest path towards realising this goal is to hold a sample of antihydrogen in an atomic trap for interrogation by electromagnetic radiation. Achieving this poses a huge experimental challenge, as state-of-the-art magnetic-minimum atom traps have well depths of only ˜1 T (˜0.5 K for ground state antihydrogen atoms). The atoms annihilate on contact with matter and must be `born' inside the magnetic trap with low kinetic energies. At the ALPHA experiment, antihydrogen atoms are produced from antiprotons and positrons stored in the form of non-neutral plasmas, where the typical electrostatic potential energy per particle is on the order of electronvolts, more than 104 times the maximum trappable kinetic energy. In November 2010, ALPHA published the observation of 38 antiproton annihilations due to antihydrogen atoms that had been trapped for at least 172 ms and then released—the first instance of a purely antimatter atomic system confined for any length of time (Andresen et al., Nature 468:673, 2010). We present a description of the main components of the ALPHA traps and detectors that were key to realising this result. We discuss how the antihydrogen atoms were identified and how they were discriminated from the background processes. Since the results published in Andresen et al. (Nature 468:673, 2010), refinements in the antihydrogen production technique have allowed many more antihydrogen atoms to be trapped, and held for much longer times. We have identified antihydrogen atoms that have been trapped for at least 1,000 s in the apparatus (Andresen et al., Nature Physics 7:558, 2011). This is more than sufficient time to interrogate the atoms spectroscopically, as well as to ensure that they have relaxed to their ground state.

  19. Customized oligonucleotide microchips that convert multiple genetic information to simple patterns, are portable and reusable

    DOEpatents

    Mirzabekov, Andrei; Guschin, Dmitry Y.; Chik, Valentine; Drobyshev, Aleksei; Fotin, Alexander; Yershov, Gennadiy; Lysov, Yuri

    2002-01-01

    This invention relates to using customized oligonucleotide microchips as biosensors for the detection and identification of nucleic acids specific for different genes, organisms and/or individuals in the environment, in food and in biological samples. The microchips are designed to convert multiple bits of genetic information into simpler patterns of signals that are interpreted as a unit. Because of an improved method of hybridizing oligonucleotides from samples to microchips, microchips are reusable and transportable. For field study, portable laser or bar code scanners are suitable.

  20. Microchip-based detection of magnetically labeled cancer biomarkers☆

    PubMed Central

    Muluneh, Melaku; Issadore, David

    2015-01-01

    Micro-magnetic sensing and actuation have emerged as powerful tools for the diagnosis and monitoring of cancer. These technologies can be miniaturized and integrated onto compact, microfluidic platforms, enabling molecular diagnostics to be performed in practical clinical settings. Molecular targets tagged with magnetic nanoparticles can be detected with high sensitivity directly in unprocessed clinical samples (e.g. blood, sputum) due to the inherently negligible magnetic susceptibility of biological material. As a result, magnetic microchip-based diagnostics have been applied with great success to the isolation and detection of rare cells and the measurement of sparse soluble proteins. In this paper, we review recent advances in microchip-based detection of magnetically labeled biomarkers and their translation to clinical applications in cancer. PMID:24099664

  1. Design and Fabrication of a PDMS Microchip Based Immunoassay

    SciTech Connect

    Shao, Guocheng; Wang, Wanjun; Wang, Jun; Lin, Yuehe

    2010-07-01

    In this paper, we describe the design and fabrication process of a polydimethylsiloxane (PDMS) microchip for on-chip multiplex immunoassay application. The microchip consists of a PDMS microfluidic channel layer and a micro pneumatic valve control layer. By selectively pressurizing the pneumatic microvalves, immuno reagents were controlled to flow and react in certain fluidic channel sites. Cross contamination was prevented by tightly closed valves. Our design was proposed to utilize PDMS micro channel surface as the solid phase immunoassay substrate and simultaneously detect four targets antigens on chip. Experiment result shows that 20psi valve pressure is sufficient to tightly close a 200µm wide micro channel with flow rate up to 20µl/min.

  2. 1.6 μm microchip laser

    NASA Astrophysics Data System (ADS)

    Šulc, J.; Jelínková, H.; Ryba-Romanowski, W.; Lukasiewicz, T.

    2009-03-01

    Properties of new pulsed-diode-pumped Er:YVO4 and Er:YVO4+CaO microchip lasers working in an ``eye-safe'' spectral region were investigated. As a pumping source, a fiber coupled (core diameter-200 μm) laser diode emitting radiation at wavelength 976 nm was used. The laser diode was operating in pulsed regime with 3 ms pulse width, and 20 Hz repetition rate. The result obtained was 175 mW and 152 mW output peak power for the Er:YVO4 and Er:YVO4+CaO lasers, respectively. The maximal efficiency with respect to the absorbed power was ~ 5%. The laser emission for Er:YVO4 microchip was observed in detail in the range 1593 nm to 1604 nm with respect to pumping. However, for Er:YVO4+CaO crystal only 1604 nm was generated.

  3. Microchip-based detection of magnetically labeled cancer biomarkers.

    PubMed

    Muluneh, Melaku; Issadore, David

    2014-02-01

    Micro-magnetic sensing and actuation have emerged as powerful tools for the diagnosis and monitoring of cancer. These technologies can be miniaturized and integrated onto compact, microfluidic platforms, enabling molecular diagnostics to be performed in practical clinical settings. Molecular targets tagged with magnetic nanoparticles can be detected with high sensitivity directly in unprocessed clinical samples (e.g. blood, sputum) due to the inherently negligible magnetic susceptibility of biological material. As a result, magnetic microchip-based diagnostics have been applied with great success to the isolation and detection of rare cells and the measurement of sparse soluble proteins. In this paper, we review recent advances in microchip-based detection of magnetically labeled biomarkers and their translation to clinical applications in cancer.

  4. High-efficiency microchip laser with self-injection seeding.

    PubMed

    Wang, Sha; Wang, Yan-biao; Yang, Xian-heng; Feng, Guo-ying; Zhou, Shou-huan

    2015-12-10

    In this paper, we use a small bandwidth 808 nm cw Ti:sapphire laser as a pump source to pump a picosecond microchip laser. Different focal length pump focus lenses have been tested to improve laser efficiency. A maximum slope efficiency of around 20% is obtained by a 30 mm focal length lens. The pump threshold is only 13 mW. In order to reduce the timing jitter, we explored the self-injection seeding method by adding a seeding cavity to the microchip laser. A reduction factor in the timing jitter of up to a factor of 23 relative to the unseeded laser is obtained. From the experiments, we also found that higher seeding pulse energy will help to reduce the jitter more.

  5. Radially polarized cylindrical vector beams from a monolithic microchip laser

    NASA Astrophysics Data System (ADS)

    Naidoo, Darryl; Fromager, Michael; Ait-Ameur, Kamel; Forbes, Andrew

    2015-11-01

    Monolithic microchip lasers consist of a thin slice of laser crystal where the cavity mirrors are deposited directly onto the end faces. While this property makes such lasers very compact and robust, it prohibits the use of intracavity laser beam shaping techniques to produce complex light fields. We overcome this limitation and demonstrate the selection of complex light fields in the form of vector-vortex beams directly from a monolithic microchip laser. We employ pump reshaping and a thermal gradient across the crystal surface to control both the intensity and polarization profile of the output mode. In particular, we show laser oscillation on a superposition of Laguerre-Gaussian modes of zero radial and nonzero azimuthal index in both the scalar and vector regimes. Such complex light fields created directly from the source could find applications in fiber injection, materials processing and in simulating quantum processes.

  6. Variability of microchip capillary electrophoresis with conductivity detection.

    PubMed

    Tantra, Ratna; Robinson, Kenneth; Sikora, Aneta

    2014-02-01

    Microfluidic CE with conductivity detection platforms could have an impact on the future development of smaller, faster and portable devices. However, for the purpose of reliable identification and quantification, there is a need to understand the degree of irreproducibility associated with the analytical technique. In this study, a protocol was developed to remove baseline drift problems sometimes observed in such devices. The protocol, which consisted of pre-conditioning steps prior to analysis, was used to further assess measurement variability from 24 individual microchips fabricated from six separate batches of glass substrate. Results show acceptable RSD percentage for retention time measurements but large variability in their corresponding peak areas (with some microchips having variability of ∼50%). Sources of variability were not related to substrate batch but possibly to a number of factors such as applied voltage fluctuations or variations in microchannel quality, for example surface roughness that will subsequently affect microchannel dimensions.

  7. On-column electrochemical detection for microchip capillary electrophoresis.

    PubMed

    Osbourn, Damon M; Lunte, Craig E

    2003-06-01

    The development of a cellulose acetate decoupler for on-column electrochemical detection in microchip capillary electrophoresis is presented. The capillary based laser-etched decoupler is translated to the planar format to isolate the detector circuit from the separation circuit. The decoupler is constructed by aligning a series of 20 30-microm holes through the coverplate of the microchip with the separation channel and casting a thin film of cellulose acetate within the holes. The decoupler shows excellent isolation of the detection circuit for separation currents up to 60 microA, with noise levels at or below 1 pA at a carbon fiber electrode. Detection limits of 25 nM were achieved for dopamine. This decoupler design combines excellent mechanical stability, effective shunting of high separation currents, and ease of manufacture.

  8. Solid-state detector and optical system for microchip analyzers

    DOEpatents

    Mathies, Richard A.; Kamei, Toshihiro; Scherer, James R.; Street, Robert A.

    2005-03-15

    A miniaturized optical excitation and detector system is described for detecting fluorescently labeled analytes in electrophoretic microchips and microarrays. The system uses miniature integrated components, light collection, optical fluorescence filtering, and an amorphous a-Si:H detector for detection. The collection of light is accomplished with proximity gathering and/or a micro-lens system. Optical filtering is accomplished by integrated optical filters. Detection is accomplished utilizing a-Si:H detectors.

  9. Disposable polyester-toner electrophoresis microchips for DNA analysis.

    PubMed

    Duarte, Gabriela R M; Coltro, Wendell K T; Borba, Juliane C; Price, Carol W; Landers, James P; Carrilho, Emanuel

    2012-06-07

    Microchip electrophoresis has become a powerful tool for DNA separation, offering all of the advantages typically associated with miniaturized techniques: high speed, high resolution, ease of automation, and great versatility for both routine and research applications. Various substrate materials have been used to produce microchips for DNA separations, including conventional (glass, silicon, and quartz) and alternative (polymers) platforms. In this study, we perform DNA separation in a simple and low-cost polyester-toner (PeT)-based electrophoresis microchip. PeT devices were fabricated by a direct-printing process using a 600 dpi-resolution laser printer. DNA separations were performed on PeT chip with channels filled with polymer solutions (0.5% m/v hydroxyethylcellulose or hydroxypropylcellulose) at electric fields ranging from 100 to 300 V cm(-1). Separation of DNA fragments between 100 and 1000 bp, with good correlation of the size of DNA fragments and mobility, was achieved in this system. Although the mobility increased with increasing electric field, separations showed the same profile regardless of the electric field. The system provided good separation efficiency (215,000 plates per m for the 500 bp fragment) and the separation was completed in 4 min for 1000 bp fragment ladder. The cost of a given chip is approximately $0.15 and it takes less than 10 minutes to prepare a single device.

  10. [Development of microchips for the analysis of biomarkers in blood].

    PubMed

    Kataoka, Masatoshi; Abe, Kaori; Hashimoto, Yoshiko; Yamamura, Shohei; Yatsushiro, Shouki

    2012-11-01

    Several types of microchips have been developed for application in clinical diagnosis. A microchip made of cyclic olefin copolymer with straight microchannels (300 microm width and 100 microm depth) was employed for sandwich ELISA for the determination of serum type I C-peptide (PICP), a biomarker of osteoporosis. This assay enabled us to determine PICP with accuracy and high sensitivity, reducing the time for the immunoassay to 1/6, and the consumption of samples and reagents to 1/50 compared with the conventional method. Furthermore, cell microarray chips with 20,944 microchambers (105 microm width and 50 microm depth), made of polystyrene, were employed for malaria diagnosis and the detection of carcinoma cells among the leukocytes. Around 100 erythrocytes or leukocytes were accommodated in each microchamber with the formation of a monolayer. For malaria diagnosis, it offered 10-100 times higher sensitivity in the detection of malaria infected erythrocytes than conventional light microscopy, and easy operation within 15 min. By double staining for epithelial cells on the cell microarray chip, one carcinoma cell could be detected among 1,800,000 leukocytes. These results indicate the potential of microchips for clinic diagnosis.

  11. Microchip system for monitoring microbial physiological behaviour under drug influences.

    PubMed

    Arora, S; Lim, C S; Foo, J Y; Sakharkar, M K; Dixit, P; Liu, A Q; Miao, J M

    2009-08-01

    Single-step real-time high-throughput monitoring of drug influences on bacterial cell behaviour has become important with growing interests in personalized therapy and medication. Conventional microchip assemblies to perform similar work do exist. However, most of these devices have complex set-ups incorporating micromixers, separators, pumps, or valves. These microcomponents can sometimes damage the entities being monitored because of the creation of unfavourable biological environments. This paper presents a microchip-based system that enables single-step mixing of two solutions in various ratios, without the need for additional microcomponents such as mixers and pumps, in order to screen effectively their combinatory effects on cell outcomes. In this work, in-vitro experiments were carried out using ampicillin at various concentrations to investigate their effects on Escherichia coli (E. coli). Results showed that the microchip provided effective screening, which yielded useful results such as effective dosages, ineffective dosages, and other possible outcomes; for instance, in this case, the occurrence of adaptive mutation of the bacteria at certain drug concentrations. Comparative microbiological laboratory tests were carried out as standard for confirmation of the results.

  12. Nucleic Acid Isolation and Enrichment on a Microchip.

    PubMed

    Kim, Jinho; Hilton, John P; Yang, Kyung A; Pei, Renjun; Stojanovic, Milan; Lin, Qiao

    2013-06-01

    This paper presents a microchip that isolates and enriches target-binding single-stranded DNA (ssDNA) from a randomized DNA mixture using a combination of solid-phase extraction and electrophoresis. Strands of ssDNA in a randomized mixture are captured via specific binding onto target-functionalized microbeads in a microchamber. The strands are further separated from impurities and enriched on-chip via electrophoresis. The microchip consists of two microchambers that are connected by a channel filled with agarose gel. In the isolation chamber, beads functionalized with human immunoglobulin E (IgE) are retained by a weir structure. An integrated heater elevates the temperature in the chamber to elute desired ssDNA from the beads, and electrophoretic transport of the DNA through the gel to the second chamber is accomplished by applying an electric potential difference between the two chambers. Experimental results show that ssDNA expressing binding affinity to IgE was captured and enriched from a sample of ssDNA with random sequences, demonstrating the potential of the microchip to enhance the sensitivity of ssDNA detection methods in dilute and complex biological samples.

  13. Recent developments in optical detection methods for microchip separations.

    PubMed

    Götz, Sebastian; Karst, Uwe

    2007-01-01

    This paper summarizes the features and performances of optical detection systems currently applied in order to monitor separations on microchip devices. Fluorescence detection, which delivers very high sensitivity and selectivity, is still the most widely applied method of detection. Instruments utilizing laser-induced fluorescence (LIF) and lamp-based fluorescence along with recent applications of light-emitting diodes (LED) as excitation sources are also covered in this paper. Since chemiluminescence detection can be achieved using extremely simple devices which no longer require light sources and optical components for focusing and collimation, interesting approaches based on this technique are presented, too. Although UV/vis absorbance is a detection method that is commonly used in standard desktop electrophoresis and liquid chromatography instruments, it has not yet reached the same level of popularity for microchip applications. Current applications of UV/vis absorbance detection to microchip separations and innovative approaches that increase sensitivity are described. This article, which contains 85 references, focuses on developments and applications published within the last three years, points out exciting new approaches, and provides future perspectives on this field.

  14. Reduced-size microchips for identification of horses: response to implantation and readability during a six-month period.

    PubMed

    Wulf, M; Aurich, C; von Lewinski, M; Möstl, E; Aurich, J E

    2013-11-09

    In this study, readability of reduced-size microchips in horses and the response to implantation were analysed. It was hypothesised that small microchips can be implanted stress-free but are less readable than larger microchips. Adult mares (n=40) were implanted with a reduced-size microchip (10.9×1.6 mm) at the left side of the neck (size of conventional microchips 11.4×2.2 mm). Microchips were identified with three different scanners (A, B, C) immediately, and at 6, 12 and 28 weeks after implantation. Twelve out of the 40 mares were submitted to microchip implantation and control treatments and cortisol, heart rate and heart rate variability (HRV) were determined. From the chip-bearing side of the neck, microchips were identified with all scanners in all horses at all times. From the contralateral side, correct readings were always 100 per cent with scanner C and with scanners A and B ranged between 60 and 100 per cent. Heart rate and HRV variable sd of beat-to-beat interval increased slightly (P<0.01) at microchip implantation and control treatment, but cortisol concentration did not increase. In conclusion, reduced-size microchips are highly reliable for identification of horses. Compared with conventional microchips, the reduction in size did not impair readability. Microchip implantation is no pronounced stressor for horses.

  15. Vortex rings

    NASA Technical Reports Server (NTRS)

    Shariff, Karim; Leonard, Anthony

    1992-01-01

    The vortex-ring problem in fluid mechanics is examined generally in terms of formation, the steady state, the duration of the rings, and vortex interactions. The formation is studied by examining the generation of laminar and turbulent vortex rings and their resulting structures with attention given to the three stages of laminar ring development. Inviscid dynamics is addressed to show how core dynamics affects overall ring motion, and laminar vortex structures are described in two dimensions. Viscous and inviscid structures are related in terms of 'leapfrogging', head-on collisions, and collisions with a no-slip wall. Linear instability theory is shown to successfully describe observational data, although late stages in the breakdown are not completely understood. This study of vortex rings has important implications for key aerodynamic issues including sound generation, transport and mixing, and vortex interactions.

  16. Microchip separations-based sensors for cellular analysis

    NASA Astrophysics Data System (ADS)

    Manica, Drew Prentice

    The objective of this thesis has been to introduce and develop novel methods for microchip separations for bioanalytical applications. A novel detection scheme is introduced, involving simultaneous dual amperometric and fluorescence detection on a microchip. Dual detection is shown to increase selectivity and throughput, resolve co-migrating species that may be selectively detected, and provide a convenient means to normalize for the irreproducibility of migration times often encountered in CE applications. Such normalization is expected to facilitate the use of microchip CE to monitor biological samples, which are inclined to exacerbate the irreproducibility of migration times. The use of electrochemical detection presents a unique and fundamental challenge. An effective method for reproducibly regenerating a clean surface is demonstrated. The method is optimized and utilized to achieve high sensitivity even for highly adsorptive compounds, such as those released from mast cells. The development of an in-situ electrode-cleaning protocol is an essential step toward reliably monitoring cellular release on a microchip CEEC device. Two novel techniques are presented which are capable of producing disposable microanalytical systems on glass. Electrodes and channels produced with these methods exhibit performance characteristics that are comparable to examples in current literature. These techniques demonstrate the feasibility of manufacturing a disposable glass lab-on-a-chip, which may be used for cellular analysis or as a point-of-use sensor. Increased interest in analyzing biological samples has led to the development of a wide range of derivatizing agents for biological compounds such as amino acids and peptides. A common tag that is both fluorescent and electroactive is naphthalene-2,3-dicarboxaldehyde (NDA). While there has been much discussion regarding the stability of a similar compound, o-phthalaldehyde, there has been no discussion regarding the stability of

  17. Integrated Acoustic Separation, Enrichment, and Microchip Polymerase Chain Reaction Detection of Bacteria from Blood for Rapid Sepsis Diagnostics.

    PubMed

    Ohlsson, Pelle; Evander, Mikael; Petersson, Klara; Mellhammar, Lisa; Lehmusvuori, Ari; Karhunen, Ulla; Soikkeli, Minna; Seppä, Titta; Tuunainen, Emilia; Spangar, Anni; von Lode, Piia; Rantakokko-Jalava, Kaisu; Otto, Gisela; Scheding, Stefan; Soukka, Tero; Wittfooth, Saara; Laurell, Thomas

    2016-10-04

    This paper describes an integrated microsystem for rapid separation, enrichment, and detection of bacteria from blood, addressing the unmet clinical need for rapid sepsis diagnostics. The blood sample is first processed in an acoustophoresis chip, where red blood cells are focused to the center of the channel by an acoustic standing wave and sequentially removed. The bacteria-containing plasma proceeds to a glass capillary with a localized acoustic standing wave field where the bacteria are trapped onto suspended polystyrene particles. The trapped bacteria are subsequently washed while held in the acoustic trap and released into a polymer microchip containing dried polymerase chain reaction (PCR) reagents, followed by thermocycling for target sequence amplification. The entire process is completed in less than 2 h. Testing with Pseudomonas putida spiked into whole blood revealed a detection limit of 1000 bacteria/mL for this first-generation analysis system. In samples from septic patients, the system was able to detect Escherichia coli in half of the cases identified by blood culture. This indicates that the current system detects bacteria in patient samples in the upper part of the of clinically relevant bacteria concentration range and that a further developed acoustic sample preparation system may open the door for a new and faster automated method to diagnose sepsis.

  18. Digital playback and improved trap design enhance capture of migrant soras and Virginia rails

    USGS Publications Warehouse

    Kearns, G.D.; Kwartin, N.B.; Brinker, D.F.; Haramis, G.M.

    1998-01-01

    We used playback of rail vocalizations and improved trap design to enhance capture of fall migrant Soras (Porzana carolina) and Virginia Rails (Rallus limicola) in marshes bordering the tidal Patuxent River, Maryland. Custom-fabricated microchip message repeating sound systems provided digitally recorded sound for long-life, high-quality playback. A single sound system accompanied each 30-45 m long drift fence trap line fitted with 1-3 cloverleaf traps. Ramped funnel entrances improved retention of captured rails and deterred raccoon (Procyon lotor) predation. Use of playback and improved trap design increased trap success by over an order of magnitude and resulted in capture and banding of 2315 Soras and 276 Virginia Rails during September and October 1993-1997. The Sora captures more than doubled the banding records for the species in North America. This capture success demonstrates the efficacy of banding large numbers of Soras and Virginia Rails on migration and winter concentration areas.

  19. Chaotic dynamics and synchronization in microchip solid-state lasers with optoelectronic feedback.

    PubMed

    Uchida, Atsushi; Mizumura, Keisuke; Yoshimori, Shigeru

    2006-12-01

    We experimentally observe the dynamics of a two-mode Nd:YVO4 microchip solid-state laser with optoelectronic feedback. The total laser output is detected and fed back to the injection current of the laser diode for pumping. Chaotic oscillations are observed in the microchip laser with optoelectronic self-feedback. We also observe the dynamics of two microchip lasers coupled mutually with optoelectronic link. The output of one laser is detected by a photodiode and the electronic signal converted from the laser output is sent to the pumping of the other laser. Chaotic fluctuation of the laser output is observed when the relaxation oscillation frequency is close to each other between the two microchip lasers. Synchronization of periodic wave form is also obtained when the microchip lasers have a single-longitudinal mode.

  20. Comparison of Digital Rectal and Microchip Transponder Thermometry in Ferrets (Mustela putorius furo)

    PubMed Central

    Maxwell, Branden M; Brunell, Marla K; Olsen, Cara H; Bentzel, David E

    2016-01-01

    Body temperature is a common physiologic parameter measured in both clinical and research settings, with rectal thermometry being implied as the ‘gold standard.’ However, rectal thermometry usually requires physical or chemical restraint, potentially causing falsely elevated readings due to animal stress. A less stressful method may eliminate this confounding variable. The current study compared 2 types of digital rectal thermometers—a calibrated digital thermometer and a common digital thermometer—with an implantable subcutaneous transponder microchip. Microchips were implanted subcutaneously between the shoulder blades of 16 ferrets (8 male, 8 female), and temperatures were measured twice from the microchip reader and once from each of the rectal thermometers. Results demonstrated the microchip temperature readings had very good to good correlation and agreement to those from both of the rectal thermometers. This study indicates that implantable temperature-sensing microchips are a reliable alternative to rectal thermometry for monitoring body temperature in ferrets. PMID:27177569

  1. 5.7  W cw single-frequency laser at 671  nm by single-pass second harmonic generation of a 17.2  W injection-locked 1342  nm Nd : YVO4 ring laser using periodically poled MgO : LiNbO3.

    PubMed

    Koch, Peter; Ruebel, Felix; Bartschke, Juergen; L'huillier, Johannes A

    2015-11-20

    We demonstrate a continuous wave single-frequency laser at 671.1 nm based on a high-power 888 nm pumped Nd:YVO4 ring laser at 1342.2 nm. Unidirectional operation of the fundamental ring laser is achieved with the injection-locking technique. A Nd:YVO4 microchip laser serves as the injecting seed source, providing a tunable single-frequency power of up to 40 mW. The ring laser emits a single-frequency power of 17.2 W with a Gaussian beam profile and a beam propagation factor of M2<1.1. A 60-mm-long periodically poled MgO-doped LiNbO3 crystal is used to generate the second harmonic in a single-pass scheme. Up to 5.7 W at 671.1 nm with a Gaussian shaped beam profile and a beam propagation factor of M2<1.2 are obtained, which is approximately twice the power of previously reported lasers. This work opens possibilities in cold atoms experiments with lithium, allowing the use of larger ensembles in magneto-optical traps or higher diffraction orders in atomic beam interferometers.

  2. Planetary Rings

    NASA Technical Reports Server (NTRS)

    Cuzzi, Jeffrey N.

    1994-01-01

    Just over two decades ago, Jim Pollack made a critical contribution to our understanding of planetary ring particle properties, and resolved a major apparent paradox between radar reflection and radio emission observations. At the time, particle properties were about all there were to study about planetary rings, and the fundamental questions were, why is Saturn the only planet with rings, how big are the particles, and what are they made of? Since then, we have received an avalanche of observations of planetary ring systems, both from spacecraft and from Earth. Meanwhile, we have seen steady progress in our understanding of the myriad ways in which gravity, fluid and statistical mechanics, and electromagnetism can combine to shape the distribution of the submicron-to-several-meter size particles which comprise ring systems into the complex webs of structure that we now know them to display. Insights gained from studies of these giant dynamical analogs have carried over into improved understanding of the formation of the planets themselves from particle disks, a subject very close to Jim's heart. The now-complete reconnaissance of the gas giant planets by spacecraft has revealed that ring systems are invariably found in association with families of regular satellites, and there is ark emerging perspective that they are not only physically but causally linked. There is also mounting evidence that many features or aspects of all planetary ring systems, if not the ring systems themselves, are considerably younger than the solar system

  3. Microchip separations of protein biotoxins using an integrated hand-held device.

    PubMed

    Fruetel, Julia A; Renzi, Ronald F; Vandernoot, Victoria A; Stamps, James; Horn, Brent A; West, Jay A A; Ferko, Scott; Crocker, Robert; Bailey, Christopher G; Arnold, Don; Wiedenman, Boyd; Choi, Wen-Yee; Yee, Daniel; Shokair, Isaac; Hasselbrink, Ernest; Paul, Philip; Rakestraw, David; Padgen, Debbie

    2005-03-01

    We report the development of a hand-held instrument capable of performing two simultaneous microchip separations (gel and zone electrophoresis), and demonstrate this instrument for the detection of protein biotoxins. Two orthogonal analysis methods are chosen over a single method in order to improve the probability of positive identification of the biotoxin in an unknown mixture. Separations are performed on a single fused-silica wafer containing two separation channels. The chip is housed in a microfluidic manifold that utilizes o-ring sealed fittings to enable facile and reproducible fluidic connection to the chip. Sample is introduced by syringe injection into a septum-sealed port on the device exterior that connects to a sample loop etched onto the chip. Detection of low nanomolar concentrations of fluorescamine-labeled proteins is achieved using a miniaturized laser-induced fluorescence detection module employing two diode lasers, one per separation channel. Independently controlled miniature high-voltage power supplies enable fully programmable electrokinetic sample injection and analysis. As a demonstration of the portability of this instrument, we evaluated its performance in a laboratory field test at the Defence Science and Technology Laboratory with a series of biotoxin variants. The two separation methods cleanly distinguish between members of a biotoxin test set. Analysis of naturally occurring variants of ricin and two closely related staphylococcal enterotoxins indicates the two methods can be used to readily identify ricin in its different forms and can discriminate between two enterotoxin isoforms.

  4. Space-time crystals of trapped ions.

    PubMed

    Li, Tongcang; Gong, Zhe-Xuan; Yin, Zhang-Qi; Quan, H T; Yin, Xiaobo; Zhang, Peng; Duan, L-M; Zhang, Xiang

    2012-10-19

    Spontaneous symmetry breaking can lead to the formation of time crystals, as well as spatial crystals. Here we propose a space-time crystal of trapped ions and a method to realize it experimentally by confining ions in a ring-shaped trapping potential with a static magnetic field. The ions spontaneously form a spatial ring crystal due to Coulomb repulsion. This ion crystal can rotate persistently at the lowest quantum energy state in magnetic fields with fractional fluxes. The persistent rotation of trapped ions produces the temporal order, leading to the formation of a space-time crystal. We show that these space-time crystals are robust for direct experimental observation. We also study the effects of finite temperatures on the persistent rotation. The proposed space-time crystals of trapped ions provide a new dimension for exploring many-body physics and emerging properties of matter.

  5. Trapped radiation belts of saturn: first look.

    PubMed

    Fillius, W; Ip, W H; McIlwain, C E

    1980-01-25

    Pioneer 11 has made the first exploration of the magnetosphere and trapped radiation belts of Saturn. Saturn's magnetosphere is intermediate in size between Earth's and Jupiter's, with trapped particle intensities comparable to Earth's. The outer region of Saturn's magnetosphere contains lower energy radiation and is variable with time; the inner region contains higher energy particles. The pitch angle distributions show a remarkable variety of field-aligned and locally mirroring configurations. The moons and especially the rings of Saturn are effective absorbers of trapped particles; underneath the rings, the trapped radiation is completely absorbed. We confirm the discovery of a new ring, called the F ring, a new division, the Pioneer division, and a moon, called 1979 S 2. The latter has probably been seen from Earth. There may be evidence for more bodies like 1979 S 2, but at this stage the interpretation of the data is ambiguous. Using particle diffusion rates, we estimate that the cross-sectional area of the F ring is > 7 x 10(13) square centimeters and that the opacity is > 10(-5). Cosmic-ray albedo neutron decay should be looked into as a source of energetic particles in the inner magnetosphere of Saturn.

  6. Solar trap

    SciTech Connect

    Lew, H.S.

    1988-02-09

    A solar trap for collecting solar energy at a concentrated level is described comprising: (a) a compound light funnel including a pair of light reflecting substantially planar members arranged into a trough having a substantially V-shaped cross section; (b) a two dimensional Fresnel lens cover covering the opening of the compound light funnel, the opening being the open diverging end of the substantially V-shaped cross section of the compound light funnel; (c) at least one conduit for carrying a heat transfer fluid disposed substantially adjacent and substantially parallel to the apex line of the compound light funnel.

  7. COLD TRAP

    DOEpatents

    Milleron, N.

    1963-03-12

    An improved linear-flow cold trap is designed for highvacuum applications such as mitigating back migration of diffusion pump oil moiecules. A central pot of liquid nitrogen is nested within and supported by a surrounding, vertical, helical coil of metai sheet, all enveloped by a larger, upright, cylindrical, vacuum vessel. The vertical interstices between successive turns of the coil afford lineal, axial, high-vacuum passages between open mouths at top and bottom of said vessel, while the coil, being cold by virtue of thermal contact of its innermost turn with the nitrogen pot, affords expansive proximate condensation surfaces. (AEC)

  8. VACUUM TRAP

    DOEpatents

    Gordon, H.S.

    1959-09-15

    An improved adsorption vacuum trap for use in vacuum systems was designed. The distinguishing feature is the placement of a plurality of torsionally deformed metallic fins within a vacuum jacket extending from the walls to the central axis so that substantially all gas molecules pass through the jacket will impinge upon the fin surfaces. T fins are heated by direct metallic conduction, thereby ol taining a uniform temperature at the adeorbing surfaces so that essentially all of the condensible impurities from the evacuating gas are removed from the vacuum system.

  9. View northeast of a microchip based computer control system installed ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View northeast of a microchip based computer control system installed in the early 1980's to replace Lamokin Tower, at center of photograph; panels 1 and 2 at right of photograph are part of main supervisory board; panel 1 controlled Allen Lane sub-station #7; responsiblity for this portion of the system was transferred to southeast Pennsylvania transit authority (septa) in 1985; panel 2 at extreme right controls catenary switches in a coach storage yard adjacent to the station - Thirtieth Street Station, Power Director Center, Thirtieth & Market Streets in Amtrak Railroad Station, Philadelphia, Philadelphia County, PA

  10. Carbon nanotube-based separation columns for microchip electrochromatography.

    PubMed

    Mogensen, K B; Delacourt, B; Kutter, J P

    2015-01-01

    Fabrication of the stationary phase for microchip chromatography is most often done by packing of the individual separation channel after fabrication of the microfluidic chip, which is a very time-consuming and costly process (Kutter. J Chromatogr A 1221:72-82, 2012). Here, we describe in detail the fabrication and operation protocols for devices with microfabricated carbon nanotube stationary phases for reverse-phase chromatography. In this protocol, the lithographically defined stationary phase is fabricated in the channel before bonding of a lid, thereby circumventing the difficult packaging procedures used in more conventional protocols.

  11. Challenges of glycoprotein analysis by microchip capillary gel electrophoresis.

    PubMed

    Engel, Nicole; Weiss, Victor U; Wenz, Christian; Rüfer, Andreas; Kratzmeier, Martin; Glück, Susanne; Marchetti-Deschmann, Martina; Allmaier, Günter

    2015-08-01

    Glycosylations severely influence a protein's biological and physicochemical properties. Five exemplary proteins with varying glycan moieties were chosen to establish molecular weight (MW) determination (sizing), quantitation, and sensitivity of detection for microchip capillary gel electrophoresis (MCGE). Although sizing showed increasing deviations from literature values (SDS-PAGE or MALDI-MS) with a concomitant higher degree of analyte glycosylation, the reproducibility of MW determination and accuracy of quantitation with high sensitivity and reliability were demonstrated. Additionally, speed of analysis together with the low level of analyte consumption render MCGE attractive as an alternative to conventional SDS-PAGE.

  12. Self-transport and self-alignment of microchips using microscopic rain.

    PubMed

    Chang, Bo; Shah, Ali; Zhou, Quan; Ras, Robin H A; Hjort, Klas

    2015-10-09

    Alignment of microchips with receptors is an important process step in the construction of integrated micro- and nanosystems for emerging technologies, and facilitating alignment by spontaneous self-assembly processes is highly desired. Previously, capillary self-alignment of microchips driven by surface tension effects on patterned surfaces has been reported, where it was essential for microchips to have sufficient overlap with receptor sites. Here we demonstrate for the first time capillary self-transport and self-alignment of microchips, where microchips are initially placed outside the corresponding receptor sites and can be self-transported by capillary force to the receptor sites followed by self-alignment. The surface consists of hydrophilic silicon receptor sites surrounded by superhydrophobic black silicon. Rain-induced microscopic droplets are used to form the meniscus for the self-transport and self-alignment. The boundary conditions for the self-transport have been explored by modeling and confirmed experimentally. The maximum permitted gap between a microchip and a receptor site is determined by the volume of the liquid and by the wetting contrast between receptor site and substrate. Microscopic rain applied on hydrophilic-superhydrophobic patterned surfaces greatly improves the capability, reliability and error-tolerance of the process, avoiding the need for accurate initial placement of microchips, and thereby greatly simplifying the alignment process.

  13. Physiological and behavioural responses of young horses to hot iron branding and microchip implantation.

    PubMed

    Erber, R; Wulf, M; Becker-Birck, M; Kaps, S; Aurich, J E; Möstl, E; Aurich, C

    2012-02-01

    Branding is the traditional and well-established method used to mark horses, but recently microchip transponders for implantation have become available. In this study, behaviour, physiological stress variables and skin temperature in foals were determined in response to hot-iron branding (n=7) and microchip implantation (n=7). Salivary cortisol concentrations increased in response to branding (1.8 ± 0.2 ng/mL) and microchip implantation (1.4 ± 0.1ng/mL), but cortisol release over time did not differ. In response to both manipulations there was a transient increase in heart rate (P<0.001) and heart rate variability (P<0.01). Branding and microchip implantation induced a comparable aversive behaviour (branding, score 3.86 ± 0.85; microchip, score 4.00 ± 0.82). Both techniques thus caused similar physiological and behavioural changes indicative of stress. Acutely, implantation of a microchip was as stressful as branding in foals. Branding caused a necrotising skin burn lasting at least 7 days. Moreover branding, but not microchip implantation (P<0.001), was accompanied by a generalized increase in skin temperature which was comparable to low degree post-burn hypermetabolism in humans.

  14. UV and circular dichroism thermal lens microscope for integrated chemical systems and HPLC on microchip

    NASA Astrophysics Data System (ADS)

    Mawatari, Kazuma; Kitamori, Takehiko

    2005-09-01

    Thermal lens microscope (TLM) is our original sensitive detector for non-fluorescent molecules in microspace. The principle is based on absorption of light followed by photothermal process. TLM has been successfully applied tosensitive detection on microchip, and TLM enabled various applications combined with microchip technologies. We are now developing HPLC microchips as one of the important separation techniques for analysis and synthesis. For HPLC microchip systems, direct and sensitive UV detection on microchip becomes key technology. Therefore, we extended applicability of TLM from visible to UV light absorbing samples by pulse UV laser excitation (UV-TLM). Quasi- continuous wave (QCW) method was applied for lock-in amplifier detection. By applying UV-TLM for biomolecules separation and detection, about two orders of higher sensitivity was achieved compared with UV spectrophotometer. For synthesis on microchip, recognition and detection of chiral samples become important in pharmaceutical field. Therefore, function of TLM was extended for selective detection of chiral samples by utilizing polarization modulation of excitation beam and resultant circular dichroism of sample (CD-TLM). The chirality of samples was detected selectively on microchip with two orders higher sensitivity than CD spectrophotometer. Finally, we explained the instrumentation using fiber optics and micro lens technology for achieving a miniaturized practical device.

  15. The nature of the TRAP–Anti-TRAP complex

    PubMed Central

    Watanabe, Masahiro; Heddle, Jonathan G.; Kikuchi, Kenichi; Unzai, Satoru; Akashi, Satoko; Park, Sam-Yong; Tame, Jeremy R. H.

    2009-01-01

    Tryptophan biosynthesis is subject to exquisite control in species of Bacillus and has become one of the best-studied model systems in gene regulation. The protein TRAP (trp RNA-binding attenuation protein) predominantly forms a ring-shaped 11-mer, which binds cognate RNA in the presence of tryptophan to suppress expression of the trp operon. TRAP is itself regulated by the protein Anti-TRAP, which binds to TRAP and prevents RNA binding. To date, the nature of this interaction has proved elusive. Here, we describe mass spectrometry and analytical centrifugation studies of the complex, and 2 crystal structures of the TRAP–Anti-TRAP complex. These crystal structures, both refined to 3.2-Å resolution, show that Anti-TRAP binds to TRAP as a trimer, sterically blocking RNA binding. Mass spectrometry shows that 11-mer TRAP may bind up to 5 AT trimers, and an artificial 12-mer TRAP may bind 6. Both forms of TRAP make the same interactions with Anti-TRAP. Crystallization of wild-type TRAP with Anti-TRAP selectively pulls the 12-mer TRAP form out of solution, so the crystal structure of wild-type TRAP–Anti-TRAP complex reflects a minor species from a mixed population. PMID:19164760

  16. A microchip for integrated single-cell genotoxicity assay.

    PubMed

    Dong, Hui; Sun, Hao; Zheng, Jianping

    2016-12-01

    With the development of large-scale biologic databases, precision medicine is becoming a frontier in biomedical research. As a main focus of precision medicine study, cancer has been widely accepted as a disease born out of inherited genetic variations or accumulating genomic damage. At the single-cell level, microfluidics or lab-on-a-chip technology for cancer study is an emerging tool for improving risk assessment, diagnostic categories and therapeutic strategies. This work presents a multi-layer microchip for single-cell gene expression profiling. Treated by three drug reagents (i.e. methyl methanesulfonate, docetaxel and colchicine) with varied concentrations and time lengths, individual human breast cancer cells (MCF-7) are then lysed on-chip, and the released mRNA templates are captured and reversely transcribed into cDNA on microbead surface. Three genes (GAPDH, CDKN1A, AURKA) are amplified and quantified simultaneously through triplex real-time polymerase chain reactions (qPCR). Readout per run is set to be eighteen, and can be further improved following same approach. The microchip is able to integrate all steps of single-cell gene expression profiling, and provide precision study of drug induced genotoxicity with reduced reagents consumption per reaction and instrumental cost.

  17. Energy Conversion from Salinity Gradient Using Microchip with Nafion Membrane

    NASA Astrophysics Data System (ADS)

    Chang, Che-Rong; Yeh, Ching-Hua; Yeh, Hung-Chun; Yang, Ruey-Jen

    2016-06-01

    When a concentrated salt solution and a diluted salt solution are separated by an ion-selective membrane, cations and anions would diffuse at different rates depending on the ion selectivity of the membrane. The difference of positive and negative charges at both ends of the membrane would produce a potential, called the diffusion potential. Thus, electrical energy can be converted from the diffusion potential through reverse electrodialysis. This study demonstrated the fabrication of an energy conversion microchip using the standard micro-electromechanical technique, and utilizing Nafion junction as connecting membrane, which was fabricated by a surface patterned process. Through different salinity gradient of potassium chloride solutions, we experimentally investigated the diffusion potential and power generation from the microchip, and the highest value measured was 135 mV and 339 pW, respectively. Furthermore, when the electrolyte was in pH value of 3.8, 5.6, 10.3, the system exhibited best performance at pH value of 10.3; whereas, pH value of 3.8 yielded the worst.

  18. Microchip green laser sources: broad range of possibilities

    NASA Astrophysics Data System (ADS)

    Essaian, Stepan; Khaydarov, John; Slavov, Slav; Ter-Mikirtychev, Vartan; Gabrielyan, Gevorg; Keroopyan, Meruzhan; Soghomonyan, Suren

    2012-02-01

    Spectralus presents its progress in development of miniature, highly efficient, and versatile diode-pumped solid-state (DPSS) green laser source, based on a monolithic cavity microchip laser platform. The use of periodically poled MgO-doped Lithium Niobate (PPMgOLN) as the nonlinear frequency doubler together with gain material Nd3+:YVO4 allows obtaining a significant increase in the overall efficiency of the green microchip laser in comparison with other compact green laser source architectures with comparable output power. Originally, this laser source was designed to be part of the miniature and efficient RGB light source for microdisplay-based (LCOS, DLP or similar) mobile projector devices. Recently, we have extended range of operations for our original laser platform. In particular, we demonstrate the following: high peak power (>500mW), high average power (>200mW), broad temperature range of operation (-30°C - 60°C), and low noise CW operation (<0.5% RMS).

  19. Quantitative analysis of plasma interleiukin-6 by immunoassay on microchip

    NASA Astrophysics Data System (ADS)

    Abe, K.; Hashimoto, Y.; Yatsushiro, S.; Yamamura, S.; Tanaka, M.; Ooie, T.; Baba, Y.; Kataoka, M.

    2012-03-01

    Sandwich enzyme-linked immunoassay (ELISA) is one of the most frequently employed assays for clinical diagnosis, since this enables the investigator to identify specific protein biomarkers. However, the conventional assay using a 96-well microtitration plate is time- and sample-consuming, and therefore is not suitable for rapid diagnosis. To overcome these drawbacks, we performed a sandwich ELISA on a microchip. We employed the piezoelectric inkjet printing for deposition and fixation of 1st antibody on the microchannnel surface (300 μm width and 100 μm depth). Model analyte was interleukin-6 (IL-6) which was one of the inflammatory cytokine. After blocking the microchannel, antigen, biotin-labeled 2nd antibody, and avidin-labeled peroxidase were infused into the microchannel and incubated for 20 min, 10 min, and 5 min, respectively. This assay could detect 2 pg/ml and quantitatively measure the range of 0-32 pg/ml. Liner regression analysis of plasma IL-6 concentration obtained by microchip and conventional methods exhibited a significant relationship (R2 = 0.9964). This assay reduced the time for the antigen-antibody reaction to 1/6, and the consumption of samples and reagents to 1/50 compared with the conventional method. This assay enables us to determine plasma IL-6 with accuracy, high sensitivity, time saving ability, and low consumption of sample and reagents, and thus will be applicable to clinic diagnosis.

  20. A micro surface tension pump (MISPU) in a glass microchip.

    PubMed

    Peng, Xing Yue Larry

    2011-01-07

    A non-membrane micro surface tension pump (MISPU) was fabricated on a glass microchip by one-step glass etching. It needs no material other than glass and is driven by digital gas pressure. The MISPU can be seen working like a piston pump inside the glass microchip under a microscope. The design of the valves (MISVA) and pistons (MISTON) was based on the surface tension theory of the micro surface tension alveolus (MISTA). The digital gas pressure controls the moving gas-liquid interface to open or close the input and output MISVAs to refill or drive the MISTON for pumping a liquid. Without any moving parts, a MISPU is a kind of long-lasting micro pump for micro chips that does not lose its water pumping efficiency over a 20-day period. The volumetric pump output varied from 0 to 10 nl s(-1) when the pump cycle time decreased from 5 min to 15 s. The pump head pressure was 1 kPa.

  1. Integrated self-powered microchip biosensor for endogenous biological cyanide.

    PubMed

    Deng, Liu; Chen, Chaogui; Zhou, Ming; Guo, Shaojun; Wang, Erkang; Dong, Shaojun

    2010-05-15

    In this work we developed a fully integrated biofuel cell on a microchip, which consisted of glucose dehydrogenase supported (carbon nanotubes/thionine/gold nanoparticles)(8) multilayer as the anode, and the (carbon nanotubes/polylysine/laccase)(15) multilayer as the cathode. The as-obtained biofuel cell produced open circuit potential 620 mV and power density 302 microW cm(-2), showing great potential as a small power resource of portable electronics. Most importantly, for the first time we demonstrated the feasibility of developing a self-powered biosensor based on the inhibitive effect on microchip enzyme biofuel cell. With cyanide employed as the model analyte, this method showed a linear range of 3.0 x 10(-7) to 5.0 x 10(-4) M and a detection limit with 1.0 x 10(-7) M under the optimal conditions. The detection limit was lower than the acceptable cyanide concentration in drinking water (1.9 x 10(-6) M) according to the World Health Organization (WHO). This self-powered sensor was successfully used to detect the cyanide concentration in a real sample, cassava, which is the main carbohydrate resource in South America and Africa. This presented biosensor combined with a resistor and a multimeter demonstrated the general applicability as a fast and simple detection method in the determination of endogenous biological cyanide.

  2. Electro-microchip DNA-biosensor for bacteria detection.

    PubMed

    Yeh, Chia Hsien; Chang, Yu Huai; Chang, Tsung Chain; Lin, Hong Ping; Lin, Yu Cheng

    2010-10-01

    This paper presents a bacteria biosensor based on DNA hybridization detection with an electro-microchip transducer. Acinetobacter baumannii was chosen as DNA sample source, because the occurrence of bacteremia caused by Acinetobacter baumannii is high in hospitals worldwide. Our strategy is based on DNA hybridization of PCR amplified bacteria DNA with biotin labelled primers and detection enhancement using gold-streptavidin nanoparticles and Ag(+)-hydroquinone solution. Gold nanoparticles catalyze silver ions reduction by hydroquinone. The gradually precipitated silver metal between the two electrodes of the electro-microchip allows electrons to pass. The detection limit for Acinetobacter baumannii genomic DNA sample is 0.825 ng mL(-1) (1.2 fM). Probe specificity was investigated by screening various species of bacteria, various strains of a single species and various species of a single genus. The proposed DNA hybridization method is easy, convenient, and rapid. Moreover, it has potential applications in detection of bacteria causing infections and clinical diagnosis.

  3. Analytical detection of biological thiols in a microchip capillary channel.

    PubMed

    Chand, Rohit; Jha, Sandeep Kumar; Islam, Kamrul; Han, Dawoon; Shin, Ik-Soo; Kim, Yong-Sang

    2013-02-15

    Sulfur-containing amino acids, such as cysteine and homocysteine play crucial roles in biological systems for the diagnosis of medical states. In this regard, this paper deals with separation, aliquot and detection of amino thiols on a microchip capillary electrophoresis with electrochemical detection in an inverted double Y-shaped microchannel. Unlike the conventional capillary electrophoresis, the modified microchannel design helps in storing the separated thiols in different reservoirs for further analysis, if required; and also eliminates the need of electrodes regeneration. The device was fabricated using conventional photolithographic technique which consisted of gold microelectrodes on a soda lime glass wafer and microchannels in PDMS mold. Multiple detections were performed using in-house fabricated dual potentiostat. Based on amperometric detection, cysteine and homocysteine were analyzed in 105 s and 120 s, respectively after diverting in branched channels. Repeated experiments proved the good reproducibility of the device. The device produced a linear response for both cysteine and homocysteine in electrochemical analysis. To prove the practicality of device, we also analyzed cysteine and homocysteine in real blood samples without any pre-treatment. Upon calculation, the device showed a very low limit of detection of 0.05 μM. The modified microchip design shall find a broad range of analytical applications involving assays of thiols and other biological compounds.

  4. Faster and improved microchip electrophoresis using a capillary bundle.

    PubMed

    Sun, Yi; Kwok, Yien Chian; Nguyen, Nam Trung

    2007-12-01

    Joule heating generated in CE microchips is known to affect temperature gradient, electrophoretic mobility, diffusion of analytes, and ultimately the efficiency and reproducibility of the separation. One way of reducing the effect of Joule heating is to decrease the cross-section area of microchannels. Currently, due to the limit of fabrication technique and detection apparatus, the typical dimensions of CE microchannels are in the range of 50-200 microm. In this paper, we propose a novel approach of performing microchip CE in a bundle of extremely narrow channels by using photonic crystal fiber (PCF) as separation column. The PCF was simply encapsulated in a poly(methyl methacrylate) (PMMA) microchannel right after a T-shaped injector. CE was simultaneously but independently carried out in 54 narrow capillaries, each capillary with diameter of 3.7 microm. The capillary bundle could sustain high electric field strength up to 1000 V/cm due to efficient heat dissipation, thus faster and enhanced separation was attained.

  5. Online preconcentration using monoliths in electrochromatography capillary format and microchips.

    PubMed

    Augustin, Violaine; Proczek, Gaëlle; Dugay, José; Descroix, Stéphanie; Hennion, Marie-Claire

    2007-11-01

    Online preconcentration and separation of analytes using an in situ photopolymerized hexyl acrylate-based monolith stationary phase was evaluated using electrochromatography in capillary format and microchip. The band broadening occurring during the preconcentration process by frontal electrochromatography and during the desorption process by elution electrochromatography was studied. The hexyl acrylate-based monolith provides high retention for neutral analytes allowing the handling of large sample volumes and its structure allows rapid mass transfer, thus reducing the band broadening. For moderately polar analytes such as mono-chlorophenols that are slightly retained in water, it was shown that enrichment factors up to 3500 can be obtained by a hydrodynamic injection of several bed volumes for 120 min under 0.8 MPa with a decrease in efficiency of 50% and a decrease of 30% for the resolution between 2- and 3-chlorophenol. An 8 min preconcentration time allows enrichment factors above 100 for polyaromatic hydrocarbons. The interest of these monoliths when synthesized in microchip is also demonstrated. A 200-fold enrichment was easily obtained for PAHs with only 1 min as preconcentration time, without decrease in efficiency.

  6. Electrochemistry-based real-time PCR on a microchip.

    PubMed

    Yeung, Stephen S W; Lee, Thomas M H; Hsing, I-Ming

    2008-01-15

    The development of handheld instruments for point-of-care DNA analysis can potentially contribute to the medical diagnostics and environmental monitoring for decentralized applications. In this work, we demonstrate the implementation of a recently developed electrochemical real-time polymerase chain reaction (ERT-PCR) technique on a silicon-glass microchip for simultaneous DNA amplification and detection. This on-chip ERT-PCR process requires the extension of an oligonucleotide in both solution and at solid phases and intermittent electrochemical signal measurement in the presence of all the PCR reagents. Several important parameters, related to the surface passivation and electrochemical scanning of working electrodes, were investigated. It was found that the ERT-PCR's onset thermal cycle ( approximately 3-5), where the analytical signal begins to be distinguishable from the background, is much lower than that of the fluorescence-based counterparts for high template DNA situations (3 x 10(6) copies/microL). By carefully controlling the concentrations of the immobilized probe and the enzyme polymerase, improvements have been made in obtaining a meaningful electrochemical signal using a lower initial template concentration. This ERT-PCR technique on a microchip platform holds significant promise for rapid DNA detection for point-of-care testing applications.

  7. Ghostly Ring

    NASA Technical Reports Server (NTRS)

    2008-01-01

    [figure removed for brevity, see original site] Click on image for poster version

    This image shows a ghostly ring extending seven light-years across around the corpse of a massive star. The collapsed star, called a magnetar, is located at the exact center of this image. NASA's Spitzer Space Telescope imaged the mysterious ring around magnetar SGR 1900+14 in infrared light. The magnetar itself is not visible in this image, as it has not been detected at infrared wavelengths (it has been seen in X-ray light).

    Magnetars are formed when a massive giant star ends its life in a supernova explosion, leaving behind a super dense neutron star with an incredibly strong magnetic field. The ring seen by Spitzer could not have formed during the original explosion, as any material as close to the star as the ring would have been disrupted by the supernova shock wave. Scientists suspect that the ring my actually be the edges of a bubble that was hollowed out by an explosive burst from the magnetar in 1998. The very bright region near the center of the image is a cluster of young stars, which may be illuminating the inner edge of the bubble, making it look like a ring in projection.

    This composite image was taken using all three of Spitzer's science instruments. The blue color represents 8-micron infrared light taken by the infrared array camera, green is 16-micron light from the infrared spectograph, and red is 24-micron radiation from the multiband imaging photometer.

  8. Luminescent Rings

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This view shows the unlit face of Saturn's rings, visible via scattered and transmitted light. In these views, dark regions represent gaps and areas of higher particle densities, while brighter regions are filled with less dense concentrations of ring particles.

    The dim right side of the image contains nearly the entire C ring. The brighter region in the middle is the inner B ring, while the darkest part represents the dense outer B Ring. The Cassini Division and the innermost part of the A ring are at the upper-left.

    Saturn's shadow carves a dark triangle out of the lower right corner of this image.

    The image was taken in visible light with the Cassini spacecraft wide-angle camera on June 8, 2005, at a distance of approximately 433,000 kilometers (269,000 miles) from Saturn. The image scale is 22 kilometers (14 miles) per pixel.

    The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.

    For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org .

  9. Cave Rings

    DTIC Science & Technology

    2010-10-13

    hypothesis, that cave rings are formed in the same manner as coffee rings[3], that is, due to the enhanced deposition at the edges of sessile drops ...Literature The ‘splash ring’ conjecture is described in [5]. It is claimed that 45◦ is the most probable angle for secondary drops to be ejected at, and that...ring’ is the deposit formed when a sessile drop of a solution containing dissolved particles, such as coffee or salt, dries. This was investigated by

  10. Kinetic effects on signal normalization in oligonucleotide microchips with labeled immobilized probes.

    PubMed

    Pan'kov, S V; Chechetkin, V R; Somova, O G; Antonova, O V; Moiseeva, O V; Prokopenko, D V; Yurasov, R A; Gryadunov, D A; Chudinov, A V

    2009-10-01

    Among various factors affecting operation of oligonucleotide microchips, the variations in concentration and in homogeneous distribution of immobilized probes over the cells are one of the most important. The labeling of immobilized probes ensures the complete current monitoring on the probe distribution and is reliable and convenient. Using hydrogel-based oligonucleotide microchips, the applicability of Cy3-labeled immobilized probes for quality control and signal normalization after hybridization with Cy5-labeled target DNA was investigated. This study showed that proper signal normalization should be different in thermodynamic conditions and in transient regime with hybridization far from saturation. This kinetic effect holds for both hydrogel-based and surface oligonucleotide microchips. Besides proving basic features, the technique was assessed on a sampling batch of 50 microchips developed for identifying mutations responsible for rifampicin and isoniazid resistance of Mycobacterium tuberculosis.

  11. Effect of mixing on reaction-diffusion kinetics for protein hydrogel-based microchips.

    PubMed

    Zubtsov, D A; Ivanov, S M; Rubina, A Yu; Dementieva, E I; Chechetkin, V R; Zasedatelev, A S

    2006-03-09

    Protein hydrogel-based microchips are being developed for high-throughput evaluation of the concentrations and activities of various proteins. To shorten the time of analysis, the reaction-diffusion kinetics on gel microchips should be accelerated. Here we present the results of the experimental and theoretical analysis of the reaction-diffusion kinetics enforced by mixing with peristaltic pump. The experiments were carried out on gel-based protein microchips with immobilized antibodies under the conditions utilized for on-chip immunoassay. The dependence of fluorescence signals at saturation and corresponding saturation times on the concentrations of immobilized antibodies and antigen in solution proved to be in good agreement with theoretical predictions. It is shown that the enhancement of transport with peristaltic pump results in more than five-fold acceleration of binding kinetics. Our results suggest useful criteria for the optimal conditions for assays on gel microchips to balance high sensitivity and rapid fluorescence saturation kinetics.

  12. Rapid amplification of genetically modified organisms using a circular ferrofluid-driven PCR microchip.

    PubMed

    Sun, Yi; Kwok, Yien-Chian; Foo-Peng Lee, Peter; Nguyen, Nam-Trung

    2009-07-01

    The use of genetically modified organisms (GMOs) as food and in food products is becoming more and more widespread. Polymerase chain reaction (PCR) technology is extensively used for the detection of GMOs in food products in order to verify compliance with labeling requirements. In this paper, we present a novel close-loop ferrofluid-driven PCR microchip for rapid amplification of GMOs. The microchip was fabricated in polymethyl methacrylate by CO2 laser ablation and was integrated with three temperature zones. PCR solution was contained in a circular closed microchannel and was driven by magnetic force generated by an external magnet through a small oil-based ferrofluid plug. Successful amplification of genetically modified soya and maize were achieved in less than 13 min. This PCR microchip combines advantages of cycling flexibility and quick temperature transitions associated with two existing microchip PCR techniques, and it provides a cost saving and less time-consuming way to conduct preliminary screening of GMOs.

  13. R&D 100, 2016: T-Quake – Quantum-Mechanical Transmitter/Receiver Microchip

    SciTech Connect

    Tauke-Pedretti, Anna; Camacho, Ryan; Thayer, Gayle

    2016-11-07

    Applying advanced microfabrication techniques and innovative microdesign, the Sandia Enabled Communications and Authentication Network (SECANT) team has designed and produced photonic microchips capable of sending, receiving, and processing quantum signals for applications in cyber and physical security.

  14. Fibrosarcoma adjacent to the site of microchip implantation in a cat.

    PubMed

    Daly, Meighan K; Saba, Corey F; Crochik, Sonia S; Howerth, Elizabeth W; Kosarek, Carrie E; Cornell, Karen K; Roberts, Royce E; Northrup, Nicole C

    2008-04-01

    A 14-year-old spayed female domestic shorthair cat presented with an interscapular mass. A computed tomography scan, biopsy, and histological examination revealed a fibrosarcoma adjacent to a pet identification microchip. Because the cat was previously vaccinated at this site, it is not possible to establish definitive causation of the fibrosarcoma, but this is the first report of a tumor in the vicinity of a microchip in a cat. Microchip-associated tumors have been reported in rodents and dogs. Veterinarians should be aware that because inflammation may predispose felines to tumor formation, separation and observation of vaccination and implantation sites are indicated. Adherence to American Association of Feline Practitioners (AAFP) vaccination guidelines and monitoring of microchip implantation sites are recommended.

  15. Coupling Microdialysis Sampling to Microchip Electrophoresis in a Reversibly Sealed Device.

    PubMed

    Mecker, Laura C; Martin, R Scott

    2007-10-01

    In this paper, we describe the fabrication and characterization of a reversibly sealed microchip device that is used to couple microdialysis sampling to microchip electrophoresis. The ability to interface microdialysis sampling and microchip electrophoresis in a device that is amenable to reversible sealing is advantageous from a repeated use standpoint. Commercially available tubing coming from the microdialysis probe is directly inserted into the chip and flow from the probe is interfaced to the electrophoresis portion of the device through integrated pneumatic valves. Fluorescence detection was used to characterize the poly(dimethylsiloxane)-based device in terms of injection reproducibility. It was found that the entire system (microdialysis probe and microchip device) has a concentration response lag time of 170 sec. Microdialysis sampling followed by an electrophoretic separation of amino acids derivatized with naphthalene-2,3-dicarboxaldehyde/cyanide was also demonstrated.

  16. Acupuncture injection for field amplified sample stacking and glass microchip-based capillary gel electrophoresis.

    PubMed

    Ha, Ji Won; Hahn, Jong Hoon

    2017-02-01

    Acupuncture sample injection is a simple method to deliver well-defined nanoliter-scale sample plugs in PDMS microfluidic channels. This acupuncture injection method in microchip CE has several advantages, including minimization of sample consumption, the capability of serial injections of different sample solutions into the same microchannel, and the capability of injecting sample plugs into any desired position of a microchannel. Herein, we demonstrate that the simple and cost-effective acupuncture sample injection method can be used for PDMS microchip-based field amplified sample stacking in the most simplified straight channel by applying a single potential. We achieved the increase in electropherogram signals for the case of sample stacking. Furthermore, we present that microchip CGE of ΦX174 DNA-HaeⅢ digest can be performed with the acupuncture injection method on a glass microchip while minimizing sample loss and voltage control hardware.

  17. The zero-frequency ion ring instability

    NASA Technical Reports Server (NTRS)

    Gary, S. P.; Pongratz, M. B.; Madland, C. D.; Swift, D. W.

    1985-01-01

    The electrostatic zero-frequency ion ring instability with wave vector perpendicular to a uniform magnetic field B is examined through linear and second-order theory as well as by computer simulation. In the simulation ions are taken as magnetized particles; the electrons are described as a massless fluid subject to E x B motion. Saturation of the instability is primarily due to broadening of the ion ring distribution. A second-order theory provides an approximate criterion for the saturation amplitude, as does a simple trapping argument. Thus, for the simulation presented here, both quasi-linear and trapping effects contribute to saturation.

  18. Zero-frequency ion ring instability

    SciTech Connect

    Gary, S.P.; Pongratz, M.B.; Madland, C.D.; Swift, D.W.

    1985-06-01

    The electrostatic zero-frequency ion ring instability with wave vector perpendicular to a uniform magnetic field B is examined through linear and second-order theory as well as by computer simulation. In the simulation ions are taken as magnetized particles; the electrons are described as a massless fluid subject to E x B motion. Saturation of the instability is primarily due to broadening of the ion ring distribution. A second-order theory provides an approximate criterion for the saturation amplitude, as does a simple trapping argument. Thus, for the simulation presented here, both quasilinear and trapping effects contribute to saturation.

  19. Micromachined Dust Traps

    NASA Technical Reports Server (NTRS)

    Bearman, Gregory H.; Bradley, James G.

    1993-01-01

    Micromachined traps devised to capture dust particles for analysis without contaminating them. Based on micromachined structures retaining particles, rather than adhesives or greases interfering with scanning-electron-microscope analysis or x-ray imaging. Unlike maze traps and traps enmeshing particles in steel wool or similar materials, micromachined traps do not obscure trapped particles. Internal geometries of traps range from simple cones to U-shapes, all formed by etching silicon.

  20. Development of a micro-potentiometric sensor for the microchip analysis of alkali ions.

    PubMed

    Smirnova, Adelina; Mawatari, Kazuma; Takahashi, Hiroko; Tanaka, Yo; Nakanishi, Hiroaki; Kitamori, Takehiko

    2009-12-01

    This paper reports on the development of a micro-potentiometric sensor based on external microelectrodes introduced into a microchip. We miniaturized reference and ion-selective electrodes (ISEs) and embedded them into a plastic (PDMS) microchip; the miniaturization of ISE was attained by using a monolithic capillary-based membrane. This sensor was applied to the detection of alkali ions (Na+, K+ and NH4+) in a microflow on the microg/L level.

  1. Microchip micellar electrokinetic chromatography separation of alkaloids with UV-absorbance spectral detection.

    PubMed

    Newman, Carl I D; Giordano, Braden C; Copper, Christine L; Collins, Greg E

    2008-02-01

    A microchip device is demonstrated for the electrophoretic separation and UV-absorbance spectral detection of four toxic alkaloids: colchicine, aconitine, strychnine, and nicotine. A fused-silica (quartz) microchip containing a simple cross geometry is utilized to perform the separations, and a miniature, fiber-optic CCD spectrometer is coupled to the microchip for detection. Sensitive UV-absorbance detection is achieved via the application of online preconcentration techniques in combination with the quartz microchip substrate which contains an etched bubble-cell for increased pathlength. The miniature CCD spectrometer is configured to detect light between 190 and 645 nm and LabView programming written in-house enables absorbance spectra as well as separations to be monitored from 210 to 400 nm. Consequently, the configuration of this microchip device facilitates qualitative and quantitative separations via simultaneous spatial and spectral resolution of solutes. UV-absorbance limits of quantification for colchicine, 20 microM (8 mg/L); strychnine, 50 microM (17 mg/L); aconitine, 50 microM (32 mg/L); and nicotine, 100 microM (16 mg/L) are demonstrated on the microchip. With the exception of aconitine, these concentrations are > or =20-times more sensitive than lethal dose monitoring requirements. Finally, this device is demonstrated to successfully detect each toxin in water, skim milk, and apple juice samples spiked at sublethal dose concentrations after a simple, SPE procedure.

  2. Optimization of RF multipole ion trap geometries

    NASA Astrophysics Data System (ADS)

    Fanghänel, Sven; Asvany, Oskar; Schlemmer, Stephan

    2017-02-01

    Radio-frequency (rf) traps are ideal places to store cold ions for spectroscopic experiments. Specific multipole configurations are suited best for different applications but have to be modified to allow e.g. for a proper overlap of a laser beam waist with the ion cloud. Therefore the corresponding trapping fields should be shaped accordingly. To achieve this goal highly accurate electrical potentials of rf multipole traps and the resulting effective trapping potentials are calculated using the boundary element method (BEM). These calculations are used to evaluate imperfections and to optimize the field geometry. For that purpose the complex fields are reduced to a small set of multipole expansion coefficients. Desirable values for these coefficients are met by systematic changes of real trap dimensions from CAD designs. The effect of misalignment of a linear quadrupole, the optimization of an optically open Paul trap, the influence of steering electrodes (end electrode and ring electrode) on a 22-pole ion trap and the effect of the micro motion on the lowest reachable temperatures in such a trap are discussed.

  3. Hybrid particle traps and conditioning procedure for gas insulated transmission lines

    DOEpatents

    Dale, Steinar J.; Cookson, Alan H.

    1982-01-01

    A gas insulated transmission line includes an outer sheath, an inner condor within the outer sheath, insulating supports supporting the inner conductor within the outer sheath, and an insulating gas electrically insulating the inner conductor from the outer sheath. An apertured particle trapping ring is disposed within the outer sheath, and the trapping ring has a pair of dielectric members secured at each longitudinal end thereof, with the dielectric members extending outwardly from the trapping ring along an arc. A support sheet having an adhesive coating thereon is secured to the trapping ring and disposed on the outer sheath within the low field region formed between the trapping ring and the outer sheath. A conditioning method used to condition the transmission line prior to activation in service comprises applying an AC voltage to the inner conductor in a plurality of voltage-time steps, with the voltage-time steps increasing in voltage magnitude while decreasing in time duration.

  4. Affinity Monolith-Integrated Microchips for Protein Purification and Concentration.

    PubMed

    Gao, Changlu; Sun, Xiuhua; Wang, Huaixin; Qiao, Wei; Hu, Bo

    2016-01-01

    Affinity chromatography is a valuable method to purify and concentrate minute amount of proteins. Monoliths with epoxy groups for affinity immobilization were prepared by direct in-situ photopolymerization of glycidyl methacrylate and ethylene glycol dimethacrylate in porogenic solvents consisting of 1-dodecanol and cyclohexanol. By integrating affinity monoliths onto a microfluidic system, targeted biomolecules can be captured and retained on affinity column, while other biomolecules having no specific interactions toward the immobilized ligands flow through the microchannel. Therefore, proteins which remain on the affinity column are purified and concentrated, and then eluted by appropriate solutions and finally, separated by microchip capillary electrophoresis. This integrated microfluidic device has been applied to the purification and separation of specific proteins (FITC-labeled human serum albumin and IgG) in a mixture.

  5. Investigation of temperature effect on cell mechanics by optofluidic microchips.

    PubMed

    Yang, Tie; Nava, Giovanni; Minzioni, Paolo; Veglione, Manuela; Bragheri, Francesca; Lelii, Francesca Demetra; Vazquez, Rebeca Martinez; Osellame, Roberto; Cristiani, Ilaria

    2015-08-01

    Here we present the results of a study concerning the effect of temperature on cell mechanical properties. Two different optofluidic microchips with external temperature control are used to investigate the temperature-induced changes of highly metastatic human melanoma cells (A375MC2) in the range of ~0 - 35 °C. By means of an integrated optical stretcher, we observe that cells' optical deformability is strongly enhanced by increasing cell and buffer-fluid temperature. This finding is supported by the results obtained from a second device, which probes the cells' ability to be squeezed through a constriction. Measured data demonstrate a marked dependence of cell mechanical properties on temperature, thus highlighting the importance of including a proper temperature-control system in the experimental apparatus.

  6. Investigation of temperature effect on cell mechanics by optofluidic microchips

    PubMed Central

    Yang, Tie; Nava, Giovanni; Minzioni, Paolo; Veglione, Manuela; Bragheri, Francesca; Lelii, Francesca Demetra; Vazquez, Rebeca Martinez; Osellame, Roberto; Cristiani, Ilaria

    2015-01-01

    Here we present the results of a study concerning the effect of temperature on cell mechanical properties. Two different optofluidic microchips with external temperature control are used to investigate the temperature-induced changes of highly metastatic human melanoma cells (A375MC2) in the range of ~0 – 35 °C. By means of an integrated optical stretcher, we observe that cells’ optical deformability is strongly enhanced by increasing cell and buffer-fluid temperature. This finding is supported by the results obtained from a second device, which probes the cells’ ability to be squeezed through a constriction. Measured data demonstrate a marked dependence of cell mechanical properties on temperature, thus highlighting the importance of including a proper temperature-control system in the experimental apparatus. PMID:26309762

  7. PMMA-based capillary electrophoresis electrochemical detection microchip fabrication

    NASA Astrophysics Data System (ADS)

    Horng, Ray-Hua; Han, Pin; Chen, Hung-Yu; Lin, Kuan-Wen; Tsai, Tung-Mung; Zen, Jyh-Myng

    2005-01-01

    In this paper, a 50 µm (depth) × 50 µm (width) microfluidic channel is made on a poly(methyl methacrylate) (PMMA) substrate using thick photoresist. Openings were drilled for buffer reservoirs on an additional piece of PMMA. A final PMMA/patterned photoresist/PMMA sandwich configuration was completed using a bonding process. The thick photoresist was used as the adhesion layer and also as the microfluidic system. Using screen-printed technology for carbon and silver electrode fabrication, the microchip electrophoretic device functions were demonstrated. Successful detection of uric acid and L-ascorbic acid (the main components in human urine) validates the functionality of the proposed system. Successful ascorbic and uric acid separation in a sample from a urine donor who had consumed 500 mg of vitamins verified the proposed biochip.

  8. Microchip electrophoresis at elevated temperatures and high separation field strengths.

    PubMed

    Mitra, Indranil; Marczak, Steven P; Jacobson, Stephen C

    2014-02-01

    We report free-solution microchip electrophoresis performed at elevated temperatures and high separation field strengths. We used microfluidic devices with 11 cm long separation channels to conduct separations at temperatures between 22 (ambient) and 45°C and field strengths from 100 to 1000 V/cm. To evaluate separation performance, N-glycans were used as a model system and labeled with 8-aminopyrene-1,3,6-trisulfonic acid to impart charge for electrophoresis and render them fluorescent. Typically, increased diffusivity at higher temperatures leads to increased axial dispersion and poor separation performance; however, we demonstrate that sufficiently high separation field strengths offset the impact of increased diffusivity in order to maintain separation efficiency. Efficiencies for these free-solution separations are the same at temperatures of 25, 35, and 45°C with separation field strengths ≥ 500 V/cm.

  9. Electrode substrate innovation for electrochemical detection in microchip electrophoresis.

    PubMed

    Randviir, Edward P; Banks, Craig E

    2015-08-01

    Microchip electrophoresis (MCE) represents the next generation of miniaturised electrophoretic devices and carry benefits such as significant improvement in analysis times, lower consumption of reagents and samples, flexibility and procedural simplicity. The devices provide a separation method for complex sample matrices and an on-board detection method for the analytical determination of a target compound. The detection part of MCE is increasingly leaning towards electrochemical methods, thus the selectivity and sensitivity of detection in MCE is dependent upon the chosen working electrode composition in addition to operating conditions of the chip such as separation voltage. Given the current plethora of electrode materials that are available, there exists a possibility to creatively integrate electrodes into MCE. This review will overview the application of several electrode materials, from the old through to the new. A particular recent focus has been the selectivity element of MCEs overcome with the use of enzymes, carbon composites and screen-printed technologies.

  10. Monitoring Cellular Events in Living Mast Cells Stimulated with an Extremely Small Amount of Fluid on a Microchip

    NASA Astrophysics Data System (ADS)

    Munaka, Tatsuya; Abe, Hirohisa; Kanai, Masaki; Sakamoto, Takashi; Nakanishi, Hiroaki; Yamaoka, Tetsuji; Shoji, Shuichi; Murakami, Akira

    2006-07-01

    We successfully developed a measurement system for real-time analysis of cellular function using a newly designed microchip. This microchip was equipped with a micro cell incubation chamber (240 nl) and was stimulated by a very small amount of stimuli (as small as 24 nl). Using the microchip system, cultivation of mast cells was successfully carried out. Monitoring of the cellular events after stimulation with an extremely small amount of fluid on a microchip was performed. This system could be applicable for various types of cellular analysis including real-time monitoring of cellular response by stimulation.

  11. Functionality of veterinary identification microchips following low- (0.5 tesla) and high-field (3 tesla) magnetic resonance imaging.

    PubMed

    Piesnack, Susann; Frame, Mairi E; Oechtering, Gerhard; Ludewig, Eberhard

    2013-01-01

    The ability to read patient identification microchips relies on the use of radiofrequency pulses. Since radiofrequency pulses also form an integral part of the magnetic resonance imaging (MRI) process, the possibility of loss of microchip function during MRI scanning is of concern. Previous clinical trials have shown microchip function to be unaffected by MR imaging using a field strength of 1 Tesla and 1.5. As veterinary MRI scanners range widely in field strength, this study was devised to determine whether exposure to lower or higher field strengths than 1 Tesla would affect the function of different types of microchip. In a phantom study, a total of 300 International Standards Organisation (ISO)-approved microchips (100 each of three different types: ISO FDX-B 1.4 × 9 mm, ISO FDX-B 2.12 × 12 mm, ISO HDX 3.8 × 23 mm) were tested in a low field (0.5) and a high field scanner (3.0 Tesla). A total of 50 microchips of each type were tested in each scanner. The phantom was composed of a fluid-filled freezer pack onto which a plastic pillow and a cardboard strip with affixed microchips were positioned. Following an MRI scan protocol simulating a head study, all of the microchips were accurately readable. Neither 0.5 nor 3 Tesla imaging affected microchip function in this study.

  12. Kayser-Fleischer Rings

    MedlinePlus

    ... to know about Wilson Disease Kayser-Fleischer Rings Definition Kayser-Fleischer Ring: Clinical sign. Brownish-yellow ring ... Diet & Nutrition Kayser-Fleischer Rings Wilson Disease FAQs Definitions Transplantation For Patients & Families Resources Membership Events Centers ...

  13. Development of a Real-Time Microchip PCR System for Portable Plant Disease Diagnosis

    PubMed Central

    Kim, Hyun Soo; Cifci, Osman S.; Vaughn-Diaz, Vanessa L.; Ma, Bo; Kim, Sungman; Abdel-Raziq, Haron; Ong, Kevin; Jo, Young-Ki; Gross, Dennis C.; Shim, Won-Bo; Han, Arum

    2013-01-01

    Rapid and accurate detection of plant pathogens in the field is crucial to prevent the proliferation of infected crops. Polymerase chain reaction (PCR) process is the most reliable and accepted method for plant pathogen diagnosis, however current conventional PCR machines are not portable and require additional post-processing steps to detect the amplified DNA (amplicon) of pathogens. Real-time PCR can directly quantify the amplicon during the DNA amplification without the need for post processing, thus more suitable for field operations, however still takes time and require large instruments that are costly and not portable. Microchip PCR systems have emerged in the past decade to miniaturize conventional PCR systems and to reduce operation time and cost. Real-time microchip PCR systems have also emerged, but unfortunately all reported portable real-time microchip PCR systems require various auxiliary instruments. Here we present a stand-alone real-time microchip PCR system composed of a PCR reaction chamber microchip with integrated thin-film heater, a compact fluorescence detector to detect amplified DNA, a microcontroller to control the entire thermocycling operation with data acquisition capability, and a battery. The entire system is 25×16×8 cm3 in size and 843 g in weight. The disposable microchip requires only 8-µl sample volume and a single PCR run consumes 110 mAh of power. A DNA extraction protocol, notably without the use of liquid nitrogen, chemicals, and other large lab equipment, was developed for field operations. The developed real-time microchip PCR system and the DNA extraction protocol were used to successfully detect six different fungal and bacterial plant pathogens with 100% success rate to a detection limit of 5 ng/8 µl sample. PMID:24349341

  14. Development of a real-time microchip PCR system for portable plant disease diagnosis.

    PubMed

    Koo, Chiwan; Malapi-Wight, Martha; Kim, Hyun Soo; Cifci, Osman S; Vaughn-Diaz, Vanessa L; Ma, Bo; Kim, Sungman; Abdel-Raziq, Haron; Ong, Kevin; Jo, Young-Ki; Gross, Dennis C; Shim, Won-Bo; Han, Arum

    2013-01-01

    Rapid and accurate detection of plant pathogens in the field is crucial to prevent the proliferation of infected crops. Polymerase chain reaction (PCR) process is the most reliable and accepted method for plant pathogen diagnosis, however current conventional PCR machines are not portable and require additional post-processing steps to detect the amplified DNA (amplicon) of pathogens. Real-time PCR can directly quantify the amplicon during the DNA amplification without the need for post processing, thus more suitable for field operations, however still takes time and require large instruments that are costly and not portable. Microchip PCR systems have emerged in the past decade to miniaturize conventional PCR systems and to reduce operation time and cost. Real-time microchip PCR systems have also emerged, but unfortunately all reported portable real-time microchip PCR systems require various auxiliary instruments. Here we present a stand-alone real-time microchip PCR system composed of a PCR reaction chamber microchip with integrated thin-film heater, a compact fluorescence detector to detect amplified DNA, a microcontroller to control the entire thermocycling operation with data acquisition capability, and a battery. The entire system is 25 × 16 × 8 cm(3) in size and 843 g in weight. The disposable microchip requires only 8-µl sample volume and a single PCR run consumes 110 mAh of power. A DNA extraction protocol, notably without the use of liquid nitrogen, chemicals, and other large lab equipment, was developed for field operations. The developed real-time microchip PCR system and the DNA extraction protocol were used to successfully detect six different fungal and bacterial plant pathogens with 100% success rate to a detection limit of 5 ng/8 µl sample.

  15. Ion Rings for Magnetic Fusion

    SciTech Connect

    Greenly, John, B.

    2005-07-31

    reactor-scale FRC, and the FIREX program was intended to test the ideas behind this approach. We will describe in this report the technological development path and advances in physics understanding that allowed FIREX to reach a regime in which ion rings were reproducibly created with up to about half the current necessary to produce field reversal. Unfortunately, the experiments were limited to this level by a fundamental, unanticipated aspect of the physics of strong ion rings in plasma. The FIREX ring is a strongly anisotropic, current-carrying population of ions moving faster than the Alfven speed in the background plasma. The rapidly changing ring current excites very large-amplitude Alfven waves in the plasma, and these waves strongly affect the ring, causing rapid energy loss in a way that is not compatible with the success of the ring trapping scenario around which FIREX was designed. The result was that FIREX rings were always very short-lived. We will discuss the implication of these results for possible future use of large-orbit ions in FRCs. In short, it appears that a certain range of the parameters characterizing the ring Alfven mach number and distribution function must be avoided to allow the existence of a long-lived energetic ion component in an FRC. This report will explain why FIREX experimental results cannot be directly scaled to quantitatively predict this range for a particular FRC configuration. This will require accurate, three-dimensional simulations. FIREX results do constitute a very good dataset for validating such a code, and simulations already carried out during this program provide a guide to the important physics involved.

  16. Trapped radiation belts of Saturn - First look

    NASA Technical Reports Server (NTRS)

    Fillius, W.; Ip, W. H.; Mcilwain, C. E.

    1980-01-01

    Data on the magnetosphere of Saturn obtained with the trapped radiation detector package on board the Pioneer 11 spacecraft is reported. Radiation belt profiles determined by the trapped radiation detectors on Pioneer 10 and 11 indicate that Saturn's magnetosphere is intermediate in size between those of the earth and Jupiter, with particle intensities similar to those of the earth. The outer region of the Saturn magnetosphere is found to contain particles of lower energy than the outer region, being strongly influenced by the time-varying solar wind. The moons and rings of Saturn are observed to be effective absorbers of trapped particles, confirming the discoveries of the F ring, the Pioneer ring division and the moon 1979 S 2. Particle diffusion rates are used to estimate a cross-sectional area of greater than 7 x 10 to the 13th sq cm and an opacity greater than 0.00001 for the F ring. It is suggested that cosmic-ray albedo neutron decay be studied as a possible source of energetic particles in the inner magnetosphere of Saturn.

  17. Dynamically adjustable annular laser trapping based on axicons

    SciTech Connect

    Shao, Bing; Esener, Sadik C.; Nascimento, Jaclyn M.; Botvinick, Elliot L.; Berns, Michael W

    2006-09-01

    To study the chemotactic response of sperm to an egg and to characterize sperm motility, an annular laser trap based on axicons is designed, simulated with the ray-tracing tool, and implemented. The diameter of the trapping ring can be adjusted dynamically for a range of over 400 {mu}m by simply translating one axicon along the optical axis. Trapping experiments with microspheres and dog sperm demonstrate the feasibility of the system,and the power requirement agrees with theoretical expectation. This new type of laser trapping could provide a prototype of a parallel, objective, and quantitative tool for animal fertility and biotropism study.

  18. Dynamically adjustable annular laser trapping based on axicons

    NASA Astrophysics Data System (ADS)

    Shao, Bing; Esener, Sadik C.; Nascimento, Jaclyn M.; Botvinick, Elliot L.; Berns, Michael W.

    2006-09-01

    To study the chemotactic response of sperm to an egg and to characterize sperm motility, an annular laser trap based on axicons is designed, simulated with the ray-tracing tool, and implemented. The diameter of the trapping ring can be adjusted dynamically for a range of over 400 μm by simply translating one axicon along the optical axis. Trapping experiments with microspheres and dog sperm demonstrate the feasibility of the system, and the power requirement agrees with theoretical expectation. This new type of laser trapping could provide a prototype of a parallel, objective, and quantitative tool for animal fertility and biotropism study.

  19. Trapping polar molecules in an ac trap

    SciTech Connect

    Bethlem, Hendrick L.; Veldhoven, Jacqueline van; Schnell, Melanie; Meijer, Gerard

    2006-12-15

    Polar molecules in high-field seeking states cannot be trapped in static traps as Maxwell's equations do not allow a maximum of the electric field in free space. It is possible to generate an electric field that has a saddle point by superposing an inhomogeneous electric field to an homogeneous electric field. In such a field, molecules are focused along one direction, while being defocused along the other. By reversing the direction of the inhomogeneous electric field the focusing and defocusing directions are reversed. When the fields are being switched back and forth at the appropriate rate, this leads to a net focusing force in all directions. We describe possible electrode geometries for creating the desired fields and discuss their merits. Trapping of {sup 15}ND{sub 3} ammonia molecules in a cylindrically symmetric ac trap is demonstrated. We present measurements of the spatial distribution of the trapped cloud as a function of the settings of the trap and compare these to both a simple model assuming a linear force and to full three-dimensional simulations of the experiment. With the optimal settings, molecules within a phase-space volume of 270 mm{sup 3} (m/s){sup 3} remain trapped. This corresponds to a trap depth of about 5 mK and a trap volume of about 20 mm{sup 3}.

  20. Ringing wormholes

    SciTech Connect

    Konoplya, R.A.; Molina, C.

    2005-06-15

    We investigate the response of traversable wormholes to external perturbations through finding their characteristic frequencies and time-domain profiles. The considered solution describes traversable wormholes between the branes in the two brane Randall-Sundrum model and was previously found within Einstein gravity with a conformally coupled scalar field. The evolution of perturbations of a wormhole is similar to that of a black hole and represents damped oscillations (ringing) at intermediately late times, which are suppressed by power-law tails (proportional to t{sup -2} for monopole perturbations) at asymptotically late times.

  1. Monolithic thermally bonded Er3+, Yb3+:glass/Co2+:MgAl2O4 microchip lasers

    NASA Astrophysics Data System (ADS)

    Mlynczak, Jaroslaw; Belghachem, Nabil

    2015-12-01

    The highest ever reported 10 kW peak power in monolithic thermally bonded Er3+, Yb3+:glass/Co2+:MgAl2O4 microchip laser was achieved. To show the superiority of monolithic microchip lasers over those with external mirrors the laser generation characteristics of the same samples in both cases were compared.

  2. Development of an integrated direct-contacting optical-fiber microchip with light-emitting diode-induced fluorescence detection.

    PubMed

    Liu, Changchun; Cui, Dafu; Chen, Xing

    2007-11-02

    In this paper, one poly(dimethylsiloxane) (PDMS) sandwich microchip integrated with one direct-contacting optical fiber was fabricated by using a thin-casting method. This novel integrated PDMS sandwich microchip included top glass plate, PDMS membrane replica with microfluidic networks and optical fiber, flat PDMS membrane and bottom glass plate. As the tip of excitation optical fiber completely contacted with the separation microchannel in this integrated microchip, it not only increased the excitation light intensity to achieve the high sensitivity, but also reduced the diameter of excitation beam to obtain high resolution. In addition, we found that this rigid PDMS sandwich microchip structure effectively prevented PDMS microchannel distortion from rigid optical fiber, and provided a substantial convenience for microchips manipulating. A blue light-emitting diode (LED) was applied as excitation source by using optical fiber to couple excitation light into its direct-contacting microchannel for fluorescence detection. The performances of this integrated PDMS sandwich microchip was demonstrated by separating the mixture of sodium fluorescein (SF) and fluorescein isothiocyanate isomer I (FITC), and showed a higher sensitive and resolution than those obtained from the conventional integrated optical-fiber PDMS microchip with a 100-microm distance between fiber tip and separation microchannel. Additionally, the reproducibility of this integrated microchip with LED-induced fluorescence detection was also examined by separation of a mixture of FITC-labeled amino acids.

  3. Microchip-based multiplex electro-immunosensing system for the detection of cancer biomarkers.

    PubMed

    Ko, Yong-Jun; Maeng, Joon-Ho; Ahn, Yoomin; Hwang, Seung Yong; Cho, Nahm-Gyoo; Lee, Seoung-Hwan

    2008-08-01

    Microfluidic-based microchips have become the focus of research interest for immunoassays and biomarker diagnostics. This is due to their aptitude for high-throughput processing, small sample volume, and short analysis times. In this paper, we describe the development of a microchip-based multiplex electro-immunosensing system for simultaneous detection of cancer biomarkers using gold nanoparticles and silver enhancer. Our microchip is composed of biocompatible poly(PDMS) and glass substrates. To fix the antibody-immobilized microbeads, we used pillar-type microfilters within a reaction chamber. An immunogold silver staining (IGSS) method was used to amplify the electrical signal that corresponded to the immune complex. To demonstrate this approach, we simultaneously assayed three cancer biomarkers, alpha-fetoprotein (AFP), carcinoembryonic antigen (CEA), and prostate-specific antigen (PSA) on the microchip. The electrical signal generated from the result of the immunoreaction was measured and monitored by a PC-based system. The overall assay time was reduced from 3-8 h to about 55 min when compared to conventional immunoassays. The working range of the proposed microchip was from 10(-3) to 10(-1) microg/mL of the target antigen.

  4. Integration of nanoparticle cell lysis and microchip PCR for one-step rapid detection of bacteria.

    PubMed

    Wan, Weijie; Yeow, John T W

    2012-04-01

    This paper describes an integrated microchip system as an efficient and cost-effective solution involving Nanotechnology and Lab-on-a-Chip technology for the rapid detection of bacteria. The system is based on using surface-modified gold nanoparticles for efficient cell lysis followed by microchip PCR without having to remove the nanoparticles from the PCR solution. Poly(quaternary ammonium) modified gold nanoparticles are used to provide a novel and efficient cell lysis method without the need to go through time-consuming, expensive and complicated microfabrication processes as most of current cell lysis methods for Lab-on-a-Chip applications do. It also facilitates the integration of cell lysis and PCR by sharing the same reaction chamber as PCR uses. It is integrated with a prototype microchip PCR system consisting of a physical microchip PCR device and an automated temperature control mechanism. The research work explores solutions for the problem of PCR inhibition caused by gold nanoparticles as well as for the problem of non-specific PCR amplification in the integrated microchip system. It also explores the possibility of greatly reducing PCR cycling time to achieve the same result compared to the protocol for a regular PCR machine. The simplicity of the setup makes it easy to be integrated with other Lab-on-a-Chip functional modules to create customized solutions for target applications.

  5. A Sol-Gel-Modified Poly(methyl methacrylate) Electrophoresis Microchip with a Hydrophilic Channel Wall

    SciTech Connect

    Chen, Gang; Xu, Xuejiao; Lin, Yuehe; Wang, Joseph

    2007-07-27

    A sol-gel method was employed to fabricate a poly(methyl methacrylate) (PMMA) electrophoresis microchip that contains a hydrophilic channel wall. To fabricate such a device, tetraethoxysilane (TEOS) was injected into the PMMA channel and was allowed to diffuse into the surface layer for 24 h. After removing the excess TEOS, the channel was filled with an acidic solution for 3 h. Subsequently, the channel was flushed with water and was pretreated in an oven to obtain a sol-gel-modified PMMA microchip. The water contact angle for the sol-gel-modified PMMA was 27.4° compared with 66.3° for the pure PMMA. In addition, the electro-osmotic flow increased from 2.13×10-4 cm2 V-1 s-1 for the native-PMMA channel to 4.86×10-4 cm2 V-1 s-1 for the modified one. The analytical performance of the sol-gel-modified PMMA microchip was demonstrated for the electrophoretic separation of several purines, coupled with amperometric detection. The separation efficiency of uric acid increased to 74 882.3 m-1 compared with 14 730.5 m-1 for native-PMMA microchips. The result of this simple modification is a significant improvement in the performance of PMMA for microchip electrophoresis and microfluidic applications.

  6. Comparison of noncontact infrared thermometry and 3 commercial subcutaneous temperature transponding microchips with rectal thermometry in rhesus macaques (Macaca mulatta).

    PubMed

    Brunell, Marla K

    2012-07-01

    This study compared a noncontact infrared laser thermometer and 3 different brands of subcutaneous temperature transponding microchips with rectal thermometry in 50 rhesus macaques (Macaca mulatta). The data were analyzed by using intraclass correlation coefficients and limits of agreement. In addition, the technical capabilities and practicality of the thermometers in the clinical setting were reviewed. None of the alternative techniques investigated was equivalent to rectal thermometry in rhesus macaques. Temperatures obtained by using microchips had higher correlation and agreed more closely with rectal temperatures than did those obtained by the noncontact infrared method. However, transponding microchips did not yield consistent results. Due to difficulty in positioning nonsedated macaques in their homecage, subcutaneous microchips were not practical in the clinical setting. Furthermore, pair-housed macaques may be able to break or remove microchips from their cagemates.

  7. A Contactless Capacitance Detection System for Microchip Capillary Electrophoresis

    NASA Astrophysics Data System (ADS)

    Wu, Peter

    2008-05-01

    The design, construction and operation of a simple, inexpensive and compact high voltage power supply for use in conjunction with a simple cross, capillary electrophoresis microchip is presented. The detection system utilizes a single high voltage power supply (15 kV), a voltage divider network for obtaining the required voltages for enabling a gated injection valve, and two high voltage relays for switching between the open and closed gate sequences of the injection. The system is used to determine sodium monofluoroacetate (MFA) concentration in diluted fruit juices and tap water. A separation buffer consisting of 20 mM citric acid and histidine at pH 3.5 enabled the detection of the anion in diluted apple juice, cranberry juice, and orange juice without lengthy sample pretreatments. Limit of detection in diluted juices and tap water were determined to be 125, 167, 138, and 173 mg/L for tap water, apple juice, cranberry juice, and orange juice, respectively, based upon an S/N of 3:1. The total analysis time for detecting the MFA anion in fruit juices was less than 5 min, which represents a considerable reduction in analysis time compared to other analytical methods currently used in food analysis.

  8. Microchip separations of neutral species via micellar electrokinetic capillary chromatography

    SciTech Connect

    Moore, A.W. Jr.; Jacobson, S.C.; Ramsey, J.M.

    1995-11-15

    Micellar electrokinetic capillary chromatography (MECC) of three neutral coumarin dyes was performed on glass microchips. Manifolds of channels for analyte injection and separation were machined into one surface of the glass substrates using standard photolithographic, etching, and deposition techniques. Cover plates were then directly bonded over these channels to form capillary networks, with fluid flow in these networks controlled by varying the applied high-voltage potentials at the outlets. The separation capillary was 16.5 cm long for a serpentine channel chip and 1.3 cm long for a straight channel chip. Detection of analyte zones was accomplished by laser-induced fluorescence using the UV lines (nearly 350 nm) of an argon ion laser. At low applied electric field strengths, MECC analyses with on-chip injections gave high reproducibilities in peak areas and migration times (<1% for two of the three coumarins) and near constant separation efficiencies throughout the analysis. At high fields (>400 V/cm), analysis times were shorter, but separation efficiency decreased at later migration times. These peaks showed significant broadening, consistent with mass transfer effects. 14 refs., 6 figs., 2 tabs.

  9. Implementation of microchip electrophoresis instrumentation for future spaceflight missions.

    PubMed

    Willis, Peter A; Creamer, Jessica S; Mora, Maria F

    2015-09-01

    We present a comprehensive discussion of the role that microchip electrophoresis (ME) instrumentation could play in future NASA missions of exploration, as well as the current barriers that must be overcome to make this type of chemical investigation possible. We describe how ME would be able to fill fundamental gaps in our knowledge of the potential for past, present, or future life beyond Earth. Despite the great promise of ME for ultrasensitive portable chemical analysis, to date, it has never been used on a robotic mission of exploration to another world. We provide a current snapshot of the technology readiness level (TRL) of ME instrumentation, where the TRL is the NASA systems engineering metric used to evaluate the maturity of technology, and its fitness for implementation on missions. We explain how the NASA flight implementation process would apply specifically to ME instrumentation, and outline the scientific and technology development issues that must be addressed for ME analyses to be performed successfully on another world. We also outline research demonstrations that could be accomplished by independent researchers to help advance the TRL of ME instrumentation for future exploration missions. The overall approach described here for system development could be readily applied to a wide range of other instrumentation development efforts having broad societal and commercial impact.

  10. Microchip-Based Organophosphorus Detection Using Bienzyme Bioelectrocatalysis

    NASA Astrophysics Data System (ADS)

    Han, Yong Duk; Jeong, Chi Yong; Lee, Jun Hee; Lee, Dae-Sik; Yoon, Hyun C.

    2012-06-01

    We have developed a microsystem for the detection of organophosphorus (OP) compounds using acetylcholine esterase (AchE) and choline oxidase (ChOx) bienzyme bioelectrocatalysis. Because AchE is irreversibly inhibited by OP pesticides, the change in AchE activity with OP treatment can be traced to determine OP concentration. Polymer-associated ChOx immobilization on the working electrode surface and magnetic microparticle (MP)-assisted AchE deposition methods were employed to create an AchE-ChOx bienzyme-modified biosensing system. ChOx was immobilized on the micropatterned electrodes using poly(L-lysine), glutaraldehyde, and amine-rich interfacial surface. AchE was immobilized on the MP surface via Schiff's base formation, and the enzyme-modified MPs were deposited on the working electrode using a magnet under the microfluidic channel. The bioelectrocatalytic reaction between AchE-ChOx bienzyme cascade and the ferrocenyl electron shuttle was successfully used to detect OP with the developed microchip. This provides a self-contained and relatively easy method for OP detection. It requires minimal time and a small sample size, and has potential analytic applications in pesticides and chemical warfare agents.

  11. Microchip-based ultrafast serodiagnostic assay for tuberculosis

    PubMed Central

    Mani, Vigneshwaran; Paleja, Bhairav; Larbi, Karima; Kumar, Pavanish; Tay, Jo Ann; Siew, Jie Yee; Inci, Fatih; Wang, ShuQi; Chee, Cynthia; Wang, Yee Tang; Demirci, Utkan; De Libero, Gennaro; Singhal, Amit

    2016-01-01

    Access to point-of-care (POC), rapid, inexpensive, sensitive, and instrument-free tests for the diagnosis of tuberculosis (TB) remains a major challenge. Here, we report a simple and low-cost microchip-based TB ELISA (MTBE) platform for the detection of anti-mycobacterial IgG in plasma samples in less than 15 minutes. The MTBE employs a flow-less, magnet-actuated, bead-based ELISA for simultaneous detection of IgG responses against multiple mycobacterial antigens. Anti-trehalose 6,6′-dimycolate (TDM) IgG responses were the strongest predictor for differentiating active tuberculosis (ATB) from healthy controls (HC) and latent tuberculosis infections (LTBI). The TDM-based MTBE demonstrated superior sensitivity compared to sputum microscopy (72% vs. 56%) with 80% and 63% positivity among smear-positive and smear-negative confirmed ATB samples, respectively. Receiver operating characteristic analysis indicated good accuracy for differentiating ATB from HC (AUC = 0.77). Thus, TDM-based MTBE can be potentially used as a screening device for rapid diagnosis of active TB at the POC. PMID:27775039

  12. Microchip Immunoaffinity Electrophoresis of Antibody-Thymidine Kinase 1 Complex

    PubMed Central

    Pagaduan, Jayson V.; Ramsden, Madison; O’Neill, Kim; Woolley, Adam T.

    2015-01-01

    Thymidine kinase-1 (TK1) is an important cancer biomarker whose serum levels are elevated in early cancer development. We developed a microchip electrophoresis immunoaffinity assay to measure recombinant purified TK1 (pTK1) using an antibody that binds to human TK1. We fabricated poly(methyl methacrylate) microfluidic devices to test the feasibility of detecting antibody (Ab)-pTK1 immune complexes as a step towards TK1 analysis in clinical serum samples. We were able to separate immune complexes from unbound antibodies using 0.5X phosphate buffer saline (pH 7.4) containing 0.01% Tween-20, with 1% w/v methylcellulose that acts as a dynamic surface coating and sieving matrix. Separation of the antibody and Ab-pTK1 complex was observed within a 5 mm effective separation length. This method of detecting pTK1 is easy to perform, requires only a 10 μL sample volume, and takes just 1 minute for separation. PMID:25486911

  13. Microchip-based flow cytometry for effective detection and count

    NASA Astrophysics Data System (ADS)

    Mu, Canjun; Zhang, Zhiyi; Lin, Min; Cao, Xudong; Zhang, Feiling

    2009-06-01

    High-throughput detection and identification of foodborne pathogens are in increasing demand for rapid bacteria detections in food safety and quality monitoring. As an effective method, microchip-based flow cytometry (microcytometery) has a potential to be less expensive and high throughout, and requires less bulky instrumentation than conventional methods. In this work, a low-cost and robust microcytometer with a simple optical setup was developed for demonstrating the high-throughput identification of foodborne bacterial pathogens that integrate sample flow focusing and detection into one testing procedure. High performance identification capability was achieved through simultaneously detecting the fluorescence and scatter light emitted from micro-fabricated channel, after designing and optimizing the laser shaping optical system and the micro-channel structure to improve the excitation light intensity as well as the detection sensitivity. In our configuration, the simple testing configuration with the collection angle of 42° in the orthogonal plane to micro chip presents the best SNR for both signals through simulation and systematic measurements. As a result, the maximum throughput of 83particles/s for the fluorescence-labelled bead with diameter of 1.013μm was obtained as well as the high detection efficiency (above 99%) and the correlation percentage (above 99.5%). Apart from the high detection sensitivity and identification power, this microcytometer also has the advantages of simple optical structure, compactness and ease in building.

  14. Electrochemical methods in conjunction with capillary and microchip electrophoresis.

    PubMed

    Mark, Jonas J P; Scholz, Rebekka; Matysik, Frank-Michael

    2012-12-07

    Electromigrative techniques such as capillary and microchip electrophoresis (CE and MCE) are inherently associated with various electrochemical phenomena. The electrolytic processes occurring in the buffer reservoirs have to be considered for a proper design of miniaturized electrophoretic systems and a suitable selection of buffer composition. In addition, the control of the electroosmotic flow plays a crucial role for the optimization of CE/MCE separations. Electroanalytical methods have significant importance in the field of detection in conjunction with CE/MCE. At present, amperometric detection and contactless conductivity detection are the predominating electrochemical detection methods for CE/MCE. This paper reviews the most recent trends in the field of electrochemical detection coupled to CE/MCE. The emphasis is on methodical developments and new applications that have been published over the past five years. A rather new way for the implementation of electrochemical methods into CE systems is the concept of electrochemically assisted injection which involves the electrochemical conversions of analytes during the injection step. This approach is particularly attractive in hyphenation to mass spectrometry (MS) as it widens the range of CE-MS applications. An overview of recent developments of electrochemically assisted injection coupled to CE is presented.

  15. Electroosmotically induced hydraulic pumping on microchips: differential ion transport

    PubMed

    Culbertson; Ramsey; Ramsey

    2000-05-15

    The theory behind and operation of an electroosmotically induced hydraulic pump for microfluidic devices is reported. This microchip functional element consists of a tee intersection with one inlet channel and two outlet channels. The inlet channel is maintained at high voltage while one outlet channel is kept at ground and the other channel has no electric potential applied. A pressure-induced flow of buffer is created in both outlet channels of the tee by reducing electroosmosis in the ground channel relative to that of the inlet channel. Spatially selective reduction of electroosmosis is accomplished by coating the walls of the ground channel with a viscous polymer. The pump is shown to differentially transport ions down the two outlet channels. This ion discrimination ability of the pump is examined as a function of an analyte's electrophoretic velocity. In addition, we demonstrate that an anion can be rejected from the ground channel and made to flow only into the field-free channel if the electrophoretic velocity of the anion is greater than the pressure-generated flow in the ground channel. The velocity threshold at which anion rejection occurs can be selectively tuned by changing the flow resistance in the field-free channel relative to the ground channel.

  16. Assessment of the use of temperature-sensitive microchips to determine core body temperature in goats.

    PubMed

    Torrao, N A; Hetem, R S; Meyer, L C R; Fick, L G

    2011-03-26

    Body temperature was measured at five different body sites (retroperitoneum, groin, semimembranosus muscle, flank and shoulder) using temperature-sensitive microchips implanted in five female goats, and compared with the core body and rectal temperatures. Body temperature was measured while the goats were kept in different ambient temperatures, with and without radiant heat, as well as during a fever induced experimentally by injection of bacterial lipopolysaccharide. Bland-Altman limit of agreement analysis was used to compare the temperature measurements at the different body sites during the different interventions. Temperatures measured by the microchip implanted in the retroperitoneum showed the closest agreement (mean 0.2 °C lower) with core and rectal temperatures during all interventions, whereas temperatures measured by the microchips implanted in the groin, muscle, flank and shoulder differed from core body temperature by up to 3.5 °C during the various interventions.

  17. A review of microdialysis coupled to microchip electrophoresis for monitoring biological events

    PubMed Central

    Saylor, Rachel A.; Lunte, Susan M.

    2015-01-01

    Microdialysis is a powerful sampling technique that enables monitoring of dynamic processes in vitro and in vivo. The combination of microdialysis with chromatographic or electrophoretic methods yields along with selective detection methods yields a “separation-based sensor” capable of monitoring multiple analytes in near real time. Analysis of microdialysis samples requires techniques that are fast (<1 min), have low volume requirements (nL–pL), and, ideally, can be employed on-line. Microchip electrophoresis fulfills these requirements and also permits the possibility of integrating sample preparation and manipulation with detection strategies directly on-chip. Microdialysis coupled to microchip electrophoresis has been employed for monitoring biological events in vivo and in vitro. This review discusses technical considerations for coupling microdialysis sampling and microchip electrophoresis, including various interface designs, and current applications in the field. PMID:25637011

  18. In situ fabrication of a temperature- and ethanol-responsive smart membrane in a microchip.

    PubMed

    Sun, Yi-Meng; Wang, Wei; Wei, Yun-Yan; Deng, Nan-Nan; Liu, Zhuang; Ju, Xiao-Jie; Xie, Rui; Chu, Liang-Yin

    2014-07-21

    Here we report a simple and versatile strategy for the in situ fabrication of nanogel-containing smart membranes in microchannels of microchips. The fabrication approach is demonstrated by the in situ formation of a chitosan membrane containing poly(N-isopropylacrylamide) (PNIPAM) nanogels in a microchannel of a microchip. The PNIPAM nanogels, that allow temperature- and ethanol-responsive swelling-shrinking volume transitions, serve as smart nanovalves for controlling the diffusional permeability of solutes across the membrane. Such self-regulation of the membrane permeability is investigated by using fluorescein isothiocyanate (FITC) as a tracer molecule. This approach provides a promising strategy for the in situ fabrication of versatile nanogel-containing smart membranes within microchips via simply changing the functional nanogels for developing micro-scale detectors, sensors, separators and controlled release systems.

  19. Carbon paste-based electrochemical detectors for microchip capillary electrophoresis/electrochemistry.

    PubMed

    Martin, R S; Gawron, A J; Fogarty, B A; Regan, F B; Dempsey, E; Lunte, S M

    2001-03-01

    The first reported use of a carbon paste electrochemical detector for microchip capillary electrophoresis (CE) is described. Poly(dimethylsiloxane) (PDMS)-based microchip CE devices were constructed by reversibly sealing a PDMS layer containing separation and injection channels to a separate PDMS layer that contained carbon paste working electrodes. End-channel amperometric detection with a single electrode was used to detect amino acids derivatized with naphthalene dicarboxaldehyde. Two electrodes were placed in series for dual electrode detection. This approach was demonstrated for the detection of copper(II) peptide complexes. A major advantage of carbon paste is that catalysts can be easily incorporated into the electrode. Carbon paste that was chemically modified with cobalt phthalocyanine was used for the detection of thiols following a CE separation. These devices illustrate the potential for an easily constructed microchip CE system with a carbon-based detector that exhibits adjustable selectivity.

  20. Impact of conduit geometry on the performance of typical particulate microchip packings.

    PubMed

    Jung, Stephanie; Höltzel, Alexandra; Ehlert, Steffen; Mora, Jose-Angel; Kraiczek, Karsten; Dittmann, Monika; Rozing, Gerard P; Tallarek, Ulrich

    2009-12-15

    This work investigates the impact of conduit geometry on the chromatographic performance of typical particulate microchip packings. For this purpose, high-performance liquid chromatography (HPLC)/UV-microchips with separation channels of quadratic, trapezoidal, or Gaussian cross section were fabricated by direct laser ablation and lamination of multiple polyimide layers and then slurry-packed with either 3 or 5 microm spherical porous C8-silica particles under optimized packing conditions. Experimentally determined plate height curves for the empty microchannels are compared with dispersion coefficients from theoretical calculations. Packing densities and plate height curves for the various microchip packings are presented and conclusively explained. The 3 microm packings display a high packing density irrespective of their conduit geometries, and their performance reflects the dispersion behavior of the empty channels. Dispersion in 5 microm packings correlates with the achieved packing densities, which are limited by the number and accessibility of corners in a given conduit shape.

  1. Sorption vacuum trap

    NASA Technical Reports Server (NTRS)

    Barrington, A. E.; Caruso, A. J.

    1970-01-01

    Modified sorption trap for use in high vacuum systems contains provisions for online regeneration of sorbent material. Trap is so constructed that it has a number of encapsulated resistance heaters and a valving and pumping device for removing gases from heated sorbing material. Excessive downtime is eliminated with this trap.

  2. Ion trap simulation tools.

    SciTech Connect

    Hamlet, Benjamin Roger

    2009-02-01

    Ion traps present a potential architecture for future quantum computers. These computers are of interest due to their increased power over classical computers stemming from the superposition of states and the resulting capability to simultaneously perform many computations. This paper describes a software application used to prepare and visualize simulations of trapping and maneuvering ions in ion traps.

  3. Spectroscopy with trapped highly charged ions

    SciTech Connect

    Beiersdorfer, P

    2008-01-23

    We give an overview of atomic spectroscopy performed on electron beam ion traps at various locations throughout the world. Spectroscopy at these facilities contributes to various areas of science and engineering, including but not limited to basic atomic physics, astrophysics, extreme ultraviolet lithography, and the development of density and temperature diagnostics of fusion plasmas. These contributions are accomplished by generating, for example, spectral surveys, making precise radiative lifetime measurements, accounting for radiative power emitted in a given wavelength band, illucidating isotopic effects, and testing collisional-radiative models. While spectroscopy with electron beam ion traps had originally focused on the x-ray emission from highly charged ions interacting with the electron beam, the operating modes of such devices have expanded to study radiation in almost all wavelength bands from the visible to the hard x-ray region; and at several facilities the ions can be studied even in the absence of an electron beam. Photon emission after charge exchange or laser excitation has been observed, and the work is no longer restricted to highly charged ions. Much of the experimental capabilities are unique to electron beam ion traps, and the work performed with these devices cannot be undertaken elsewhere. However, in other areas the work on electron beam ion traps rivals the spectroscopy performed with conventional ion traps or heavy-ion storage rings. The examples we present highlight many of the capabilities of the existing electron beam ion traps and their contributions to physics.

  4. Kinetics of ring formation

    NASA Astrophysics Data System (ADS)

    Ben-Naim, E.; Krapivsky, P. L.

    2011-06-01

    We study reversible polymerization of rings. In this stochastic process, two monomers bond and, as a consequence, two disjoint rings may merge into a compound ring or a single ring may split into two fragment rings. This aggregation-fragmentation process exhibits a percolation transition with a finite-ring phase in which all rings have microscopic length and a giant-ring phase where macroscopic rings account for a finite fraction of the entire mass. Interestingly, while the total mass of the giant rings is a deterministic quantity, their total number and their sizes are stochastic quantities. The size distribution of the macroscopic rings is universal, although the span of this distribution increases with time. Moreover, the average number of giant rings scales logarithmically with system size. We introduce a card-shuffling algorithm for efficient simulation of the ring formation process and we present numerical verification of the theoretical predictions.

  5. Microchip-laser polarization control by destructive-interference resonant-grating mirror.

    PubMed

    Pigeon, F; Pommier, J C; Reynaud, S; Parriaux, O; Abdou Ahmed, M; Tonchev, S; Landru, N; Fève, J P

    2007-03-05

    An output coupler comprising a resonant grating submirror monolithically associated with a standard multilayer submirror polarizes the emission of a Nd:YAG microchip laser linearly over its full emission bandwidth by intra-mirror destructive interference for the undesired polarization. A polarization extinction ratio of more than 25 dB is obtained up to 6.1microJ pulse energy. This passively Q-switched laser performance is almost identical to that of a gratingless non-polarized microchip laser. The design and fabrication of the resonant grating mirror are described.

  6. Size-dependent conductivity dispersion of gold nanoparticle colloids in a microchip: contactless measurements

    NASA Astrophysics Data System (ADS)

    Khalafalla, M. A. H.; Mesli, A.; Widattallah, H. M.; Sellai, A.; Al-harthi, S.; Al-Lawati, Haider A. J.; Suliman, F. O.

    2014-08-01

    We performed admittance measurements to investigate the particle size dependence of the conductivity of gold nanoparticle (Diameters: 6-100 nm) colloids in electrophoresis microchip in the frequency range of 0.03-1.00 MHz. The admittance was measured with two electrodes capacitively coupled to the colloid contained in a microchip capillary channel. The imaginary and real components of the admittance showed low-frequency dispersion associated with the polarization of the nanoparticles induced by the AC electric field. This was evident from the linear dependence of the process relaxation time as a function of the square of the radius of the nanoparticle.

  7. Microchips fabricated by femtosecond laser micromachining in glass for observation of aquatic microorganisms

    NASA Astrophysics Data System (ADS)

    Hanada, Y.; Sugioka, K.; Kawano, H.; Ishikawa, I.; Miyawaki, A.; Midorikawa, K.

    2008-02-01

    We demonstrate the fabrication of three-dimensional (3D) hollow microstructures embedded in photostructurable glass by a nonlinear multiphoton absorption process using a femtosecond (fs) laser. Fs laser direct writing followed by annealing and successive wet etching in dilute hydrofluoric (HF) acid solution resulted in the rapid manufacturing of microchips with 3-D hollow microstructures for the dynamic observation of living microorganisms in fresh water. The embedded microchannel structure enables us to analyze the continuous motion of Euglena gracilis and Dinoflagellate. Such microchips, referred to as nano-aquariums realize the efficient and highly functional observation of microorganisms.

  8. Domain wall trapping and influence of the asymmetry in magnetic nanoring studied by micromagnetic simulations.

    PubMed

    Wang, X H; Wang, W Z; Kong, T F; Lew, W S

    2011-03-01

    We have studied the magnetic switching behavior of permalloy asymmetric rings using micromagnetic simulations. The simulation results have revealed that a domain wall trapping feature is present at the narrow arm of the asymmetric ring. This trapping feature is obtained via precise control of the lateral geometric features, the ring asymmetry and the film thickness. Our results show that the trapped domain walls do not annihilate until the magnetization in the wide arm is reversed under a relatively large magnetic field. Furthermore, the magnetic field strength needed to annihilate the domain wall is found to be decreasing with larger asymmetry ratio.

  9. DNA sequence analysis by hybridization with oligonucleotide microchips: MALDI mass spectrometry identification of 5mers contiguously stacked to microchip oligonucleotides

    PubMed Central

    Stomakhin, Andrey A.; Vasiliskov, Vadim A.; Timofeev, Edward; Schulga, Dennis; Cotter, Richard J.; Mirzabekov, Andrei D.

    2000-01-01

    Matrix-assisted laser desorption ionization mass spectrometry (MALDI MS) has been applied to increase the informational output from DNA sequence analysis. It has been used to analyze DNA by hybridization with microarrays of gel-immobilized oligonucleotides extended with stacked 5mers. In model experiments, a 28 nt long DNA fragment was hybridized with 10 immobilized, overlapping 8mers. Then, in a second round of hybridization DNA–8mer duplexes were hybridized with a mixture of 10 5mers. The stability of the 5mer complex with DNA was increased to raise the melting temperature of the duplex by 10–15°C as a result of stacking interaction with 8mers. Contiguous 13 bp duplexes containing an internal break were formed. MALDI MS identified one or, in some cases, two 5mers contiguously stacked to each DNA–8mer duplex formed on the microchip. Incorporating a mass label into 5mers optimized MALDI MS monitoring. This procedure enabled us to reconstitute the sequence of a model DNA fragment and identify polymorphic nucleotides. The application of MALDI MS identification of contiguously stacked 5mers to increase the length of DNA for sequence analysis is discussed. PMID:10666462

  10. Phylogenic analysis of adhesion related genes Mad1 revealed a positive selection for the evolution of trapping devices of nematode-trapping fungi.

    PubMed

    Li, Juan; Liu, Yue; Zhu, Hongyan; Zhang, Ke-Qin

    2016-03-04

    Adhesions, the major components of the extracellular fibrillar polymers which accumulate on the outer surface of adhesive traps of nematode-trapping fungi, are thought to have played important roles during the evolution of trapping devices. Phylogenetic analyses based on the genes related to adhesive materials can be of great importance for understanding the evolution of trapping devices. Recently, AoMad1, one homologous gene of the entomopathogenic fungus Metarhizium anisopliae cell wall protein MAD1, has been functionally characterized as involved in the production of adhesions in the nematode-trapping fungus Arthrobotrys oligospora. In this study, we cloned Mad1 homologous genes from nematode-trapping fungi with various trapping devices. Phylogenetic analyses suggested that species which formed nonadhesive constricting ring (CR) traps more basally placed and species with adhesive traps evolved along two lineages. Likelihood ratio tests (LRT) revealed that significant positive selective pressure likely acted on the ancestral trapping devices including both adhesive and mechanical traps, indicating that the Mad1 genes likely played important roles during the evolution of nematode-trapping fungi. Our study provides new insights into the evolution of trapping devices of nematode-trapping fungi and also contributes to understanding the importance of adhesions during the evolution of nematode-trapping fungi.

  11. Phylogenic analysis of adhesion related genes Mad1 revealed a positive selection for the evolution of trapping devices of nematode-trapping fungi

    PubMed Central

    Li, Juan; Liu, Yue; Zhu, Hongyan; Zhang, Ke-Qin

    2016-01-01

    Adhesions, the major components of the extracellular fibrillar polymers which accumulate on the outer surface of adhesive traps of nematode-trapping fungi, are thought to have played important roles during the evolution of trapping devices. Phylogenetic analyses based on the genes related to adhesive materials can be of great importance for understanding the evolution of trapping devices. Recently, AoMad1, one homologous gene of the entomopathogenic fungus Metarhizium anisopliae cell wall protein MAD1, has been functionally characterized as involved in the production of adhesions in the nematode-trapping fungus Arthrobotrys oligospora. In this study, we cloned Mad1 homologous genes from nematode-trapping fungi with various trapping devices. Phylogenetic analyses suggested that species which formed nonadhesive constricting ring (CR) traps more basally placed and species with adhesive traps evolved along two lineages. Likelihood ratio tests (LRT) revealed that significant positive selective pressure likely acted on the ancestral trapping devices including both adhesive and mechanical traps, indicating that the Mad1 genes likely played important roles during the evolution of nematode-trapping fungi. Our study provides new insights into the evolution of trapping devices of nematode-trapping fungi and also contributes to understanding the importance of adhesions during the evolution of nematode-trapping fungi. PMID:26941065

  12. Ringing phenomenon of the fiber ring resonator.

    PubMed

    Ying, Diqing; Ma, Huilian; Jin, Zhonghe

    2007-08-01

    A resonator fiber-optic gyro (R-FOG) is a high-accuracy inertial rotation sensor based on the Sagnac effect. A fiber ring resonator is the core sensing element in the R-FOG. When the frequency of the fiber ring resonator input laser is swept linearly with time, ringing of the output resonance curve is observed. The output field of the fiber ring resonator is derived from the superposition of the light transmitted through the directional coupler directly and the multiple light components circulated in the fiber ring resonator when the frequency of the laser is swept. The amplitude and phase of the output field are analyzed, and it is found that the difference in time for different light components in the fiber ring resonator to reach a point of destructive interference causes the ringing phenomenon. Finally the ringing phenomenon is observed in experiments, and the experimental results agree with the theoretical analysis well.

  13. Trapping in TITANs Cooler Penning Trap

    NASA Astrophysics Data System (ADS)

    Kootte, Brian; Lascar, Daniel; Paul, Stefan; Gwinner, Gerald; Dilling, Jens; Titan Collaboration

    2016-09-01

    Penning trap mass spectrometry provides an excellent means of determining the masses of nuclei to high precision. Highly Charged Ions (HCIs) have been successfully used at TRIUMFs Ion Trap for Atomic and Nuclear science (TITAN) to enhance the precision of mass measurements for short-lived species. The gain in precision can theoretically scale with the charge state of the ion, but recent measurements of beam properties have shown that the process of charge breeding ions to higher charge states increases the energy spread of the ion bunch sent to the Penning trap. This reduces the gain from using HCIs. In order to maximize the precision of mass measurements, we are currently performing offline commissioning of a Cooler PEnning Trap (CPET) with the purpose of sympathetically cooling HCI bunches to an energy of 1 eV/q using a plasma of electrons. This will require implementing a nested potential configuration to trap the ions and electrons in the same region so they can interact via coulomb scattering. Recent progress in testing the trapping of electrons and singly charged ions in CPET, leading towards the cooling of HCIs prior to mass measurements in TITANs will be discussed.

  14. Asymmetric dipolar ring

    DOEpatents

    Prosandeev, Sergey A.; Ponomareva, Inna V.; Kornev, Igor A.; Bellaiche, Laurent M.

    2010-11-16

    A device having a dipolar ring surrounding an interior region that is disposed asymmetrically on the ring. The dipolar ring generates a toroidal moment switchable between at least two stable states by a homogeneous field applied to the dipolar ring in the plane of the ring. The ring may be made of ferroelectric or magnetic material. In the former case, the homogeneous field is an electric field and in the latter case, the homogeneous field is a magnetic field.

  15. [THE POSSIBILITIES OF APPLICATION OF TECHNOLOGY PROTEIN MICROARRAY (MICROCHIPS) FOR ANALYSIS OF PROTEIN COMPOSITION OF BLOOD SERUM].

    PubMed

    Gumanova, N G; Klimushina, M V; Metelskaya, V A; Boitsov, S A

    2015-10-01

    The microchip technology represents convenient and relatively economic tool of analyzing specific biomarkers with the purpose to diagnose diseases, to evaluate effectiveness of therapy and to investigate signaling pathways. To analyze protein composition of blood serum certain types of finished microchips which were not applied previously on the territory of Russia. The detection from 2% to 5% out of matrix of chips depending on their variety was managed without preliminary depletion of serum (removal of proteins of major fractions). Hence, partial protein composition of blood serum can be analyzed with microchips even without preliminary removal of proteins of major fractions.

  16. Size-dependent magnetophoresis of native single super-paramagnetic nanoparticles in a microchip.

    PubMed

    Zhang, Peng; Park, Sangyoon; Kang, Seong Ho

    2013-08-25

    Real-time dynamics of native super-paramagnetic nanoparticles (SPMNPs) with different sizes were observed in a microchip at the single-particle level. Based on the optimized magnetic field conditions obtained in the single-nanoparticle study, the SPMNPs were successfully separated and detected within ~15 s from the model polydisperse mixture.

  17. Elastomeric Microchip Electrospray Emitter for Stable Cone-Jet Mode Operation in the Nanoflow Regime.

    SciTech Connect

    Kelly, Ryan T.; Tang, Keqi; Irimia, Daniel; Toner, Mehmet; Smith, Richard D.

    2008-05-15

    Despite widespread interest in applying lab-on-a-chip technologies to mass spectrometry (MS)-based analyses, the coupling of microfluidics to electrospray ionization (ESI)-MS remains challenging. We report a robust, integrated poly(dimethylsiloxane) microchip interface for ESI-MS using simple and widely accessible microfabrication procedures. The interface uses an auxiliary channel to provide electrical contact in the Taylor cone of the electrospray without sample loss or dilution. The electric field at the channel terminus is enhanced by two vertical cuts that cause the interface to taper to a line rather than to a point, and the formation of small Taylor cones at the channel exit ensures sub-nL post-column dead volumes. While comparable ESI-MS sensitivities were achieved using both microchip and conventional fused silica capillary emitters, stable cone-jet mode electrospray could be established over a far broader range of flow rates (from 50–1000 nL/min) and applied potentials using the microchip emitters. This special feature of the microchip emitter should minimize the fine tuning required for electrospray optimization and make the stable electrospray more resistant to external perturbations.

  18. Highly sensitive contactless conductivity microchips based on concentric electrodes for flow analysis.

    PubMed

    Lima, Renato S; Piazzetta, Maria H O; Gobbi, Angelo L; Segato, Thiago P; Cabral, Murilo F; Machado, Sergio A S; Carrilho, Emanuel

    2013-12-18

    In this communication, we describe for the first time the integration of concentric electrodes (wrapping around the microchannel) in microchips. The use of such electrodes has been shown to be effective towards improvement of the sensitivity and detectability in pressure-driven flow platforms incorporating C(4)D.

  19. Poly(ethylene glycol)-functionalized polymeric microchips for capillary electrophoresis.

    PubMed

    Sun, Xuefei; Li, Dan; Lee, Milton L

    2009-08-01

    Recently, we reported the synthesis, fabrication, and preliminary evaluation of poly(ethylene glycol) (PEG)-functionalized polymeric microchips that are inherently resistant to protein adsorption without surface modification in capillary electrophoresis (CE). In this study, we investigated the impact of cross-linker purity and addition of methyl methacrylate (MMA) as a comonomer on CE performance. Impure poly(ethylene glycol) diacrylate (PEGDA) induced electroosmotic flow (EOF) and increased the separation time, while the addition of MMA decreased the separation efficiency to approximately 25% of that obtained using microchips fabricated without MMA. Resultant improved microchips were evaluated for the separation of fluorescent dyes, amino acids, peptides, and proteins. A CE efficiency of 4.2 x 10(4) plates for aspartic acid in a 3.5 cm long microchannel was obtained. Chiral separation of 10 different D,L-amino acid pairs was obtained with addition of a chiral selector (i.e., beta-cyclodextrin) in the running buffer. Selectivity (alpha) and resolution (R(s)) for D,L-leucine were 1.16 and 1.64, respectively. Good reproducibility was an added advantage of these PEG-functionalized microchips.

  20. A low timing jitter picosecond microchip laser pumped by pulsed LD

    NASA Astrophysics Data System (ADS)

    Wang, Sha; Wang, Yan-biao; Feng, Guoying; Zhou, Shou-huan

    2016-07-01

    SESAM passively Q-switched microchip laser is a very promising instrument to replace mode locked lasers to obtain picosecond pulses. The biggest drawback of a passively Q-switched microchip laser is its un-avoided large timing jitter, especially when the pump intensity is low, i.e. at low laser repetition rate range. In order to obtain a low timing jitter passively Q-switched picosecond microchip laser in the whole laser repetition rate range, a 1000 kHz pulsed narrow bandwidth Fiber Bragg Grating (FBG) stablized laser diode was used as the pump source. By tuning the pump intensity, we could control the output laser frequency. In this way, we achieved a very low timing jitter passively Q-switched picosecond laser at 2.13 mW, 111.1 kHz. The relative timing jitter was only 0.0315%, which was around 100 times smaller compared with a cw LD pumped microchip working at hundred kilohertz repetition rate frequency range.

  1. A Microchip for Quantitative Analysis of CNS Axon Growth under Localized Biomolecular Treatments

    PubMed Central

    Park, Jaewon; Kim, Sunja; Park, Su Inn; Choe, Yoonsuck; Li, Jianrong; Han, Arum

    2013-01-01

    Growth capability of neurons is an essential factor in axon regeneration. To better understand how microenvironments influence axon growth, methods that allow spatial control of cellular microenvironments and easy quantification of axon growth are critically needed. Here, we present a microchip capable of physically guiding the growth directions of axons while providing physical and fluidic isolation from neuronal somata/dendrites that enables localized biomolecular treatments and linear axon growth. The microchip allows axons to grow in straight lines inside the axon compartments even after the isolation; therefore, significantly facilitating the axon length quantification process. We further developed an image processing algorithm that automatically quantifies axon growth. The effect of localized extracellular matrix components and brain-derived neurotropic factor treatments on axon growth was investigated. Results show that biomolecules may have substantially different effects on axon growth depending on where they act. For example, while chondroitin sulfate proteoglycan causes axon retraction when added to the axons, it promotes axon growth when applied to the somata. The newly developed microchip overcomes limitations of conventional axon growth research methods that lack localized control of biomolecular environments and are often performed at a significantly lower cell density for only a short period of time due to difficulty in monitoring of axonal growth. This microchip may serve as a powerful tool for investigating factors that promote axon growth and regeneration. PMID:24161788

  2. Microchip transponder thermometry for monitoring core body temperature of antelope during capture.

    PubMed

    Rey, Benjamin; Fuller, Andrea; Hetem, Robyn S; Lease, Hilary M; Mitchell, Duncan; Meyer, Leith C R

    2016-01-01

    Hyperthermia is described as the major cause of morbidity and mortality associated with capture, immobilization and restraint of wild animals. Therefore, accurately determining the core body temperature of wild animals during capture is crucial for monitoring hyperthermia and the efficacy of cooling procedures. We investigated if microchip thermometry can accurately reflect core body temperature changes during capture and cooling interventions in the springbok (Antidorcas marsupialis), a medium-sized antelope. Subcutaneous temperature measured with a temperature-sensitive microchip was a weak predictor of core body temperature measured by temperature-sensitive data loggers in the abdominal cavity (R(2)=0.32, bias >2 °C). Temperature-sensitive microchips in the gluteus muscle, however, provided an accurate estimate of core body temperature (R(2)=0.76, bias=0.012 °C). Microchips inserted into muscle therefore provide a convenient and accurate method to measure body temperature continuously in captured antelope, allowing detection of hyperthermia and the efficacy of cooling procedures.

  3. Microchip ELISA coupled with cell phone to detect ovarian cancer HE4 biomarker in urine.

    PubMed

    Wang, ShuQi; Akbas, Ragip; Demirci, Utkan

    2015-01-01

    Ovarian cancer is a leading cause of death from gynecologic cancers in the USA, and early diagnosis can potentially increase 5-year survival rate. Detection of biomarkers derived from hyperplasia of epithelial tissue by enzyme-linked immunosorbent assay (ELISA) proves to be a practical way of early diagnosis of ovarian cancer. However, ELISA is commonly performed in a laboratory setting, and it cannot be used in a clinical setting for on-site consultation. We have shown a microchip ELISA that detects HE4, an ovarian cancer biomarker, from urine using a cell phone integrated with a mobile application for imaging and data analysis. In microchip ELISA, HE4 from urine was first absorbed on the surface; the primary and secondary antibodies were subsequently anchored on the surface via immuno-reaction; and addition of substrate led to color development because of enzymatic labeling. The microchip after color development was imaged using a cell phone, and the color intensity was analyzed by an integrated mobile application. By comparing with an ELISA standard curve, the concentration of HE4 was reported on the cell phone screen. The presented microchip ELISA coupled with a cell phone is portable as opposed to traditional ELISA, and this method can facilitate the detection of ovarian cancer at the point-of-care (POC).

  4. Determination of metabolic organic acids in cerebrospinal fluid by microchip electrophoresis.

    PubMed

    Danč, Ladislav; Bodor, Róbert; Troška, Peter; Horčičiak, Michal; Masár, Marián

    2014-08-01

    A new MCE method for the determination of oxalic, citric, glycolic, lactic, and 2- and 3-hydroxybutyric acids, indicators of some metabolic and neurological diseases, in cerebrospinal fluid (CSF) was developed. MCE separations were performed on a PMMA microchip with coupled channels at lower pH (5.5) to prevent proteins interference. A double charged counter-ion, BIS-TRIS propane, was very effective in resolving the studied organic acids. The limits of detection (S/N = 3) ranging from 0.1 to 1.6 μM were obtained with the aid of contact conductivity detector implemented directly on the microchip. RSDs for migration time and peak area of organic acids in artificial and CSF samples were <0.8 and <9.7%, respectively. Recoveries of organic acids in untreated CSF samples on the microchip varied from 91 to 104%. Elimination of chloride interference, a major anionic constituent of CSF, has been reached by two approaches: (i) the use of coupled channels microchip in a column switching mode when approximately 97-99% of chloride was removed electrophoretically in the first separation channel and (ii) the implementation of micro-SPE with silver-form resin prior to the MCE analysis, which selectively removed chloride from undeproteinized CSF samples.

  5. Convenient diagnosis of spinal and bulbar muscular atrophy using a microchip electrophoresis system.

    PubMed

    Maruyama, Hirofumi; Morino, Hiroyuki; Izumi, Yuishin; Noda, Kouichi; Kawakami, Hideshi

    2013-01-01

    Spinal and bulbar muscular atrophy (SBMA) is a slowly progressive motor neuron disease. Lower and primary sensory neuronopathy is one of the major neuropathological changes that occurs in SBMA. However, many sings are common to SBMA and amyotrophic lateral sclerosis (ALS), and SBMA patients are sometimes diagnosed with ALS. Leuprorelin may be used to treat SBMA, but an accurate diagnosis is necessary for treatment and care. Genetic diagnosis can be performed to detect the expansion of a CAG repeat in the androgen receptor gene in SBMA patients. To screen for this expansion, we used a microchip electrophoresis system. The discrepancy between the actual repeat length and that found by the microchip electrophoresis system was roughly dependent on the repeat length. The mean difference was -6.8 base pairs (bp) in SBMA patients, -0.30 bp in controls. The microchip electrophoresis results were approximately 2 CAG repeats shorter than the actual repeat length in SBMA patients. Using this method, we screened our ALS samples (31 were familial, 271 were sporadic): 4 subjects were diagnosed with SBMA; 2 had familial ALS, and 2 had sporadic ALS (0.7%). The microchip electrophoresis system is semi-quantitative, convenient and useful for screening a large number of samples.

  6. Viability study of HL60 cells in contact with commonly used microchip materials.

    PubMed

    Wolbers, Floor; ter Braak, Paul; Le Gac, Severine; Luttge, Regina; Andersson, Helene; Vermes, Istvan; van den Berg, Albert

    2006-12-01

    This paper presents a study in which different commonly used microchip materials (silicon oxide, borosilicate glass, and PDMS) were analyzed for their effect on human promyelocytic leukemic (HL60) cells. Copper-coated silicon was analyzed for its toxicity and therefore served as a positive control. With quantitative PCR, the expression of the proliferation marker Cyclin D1 and the apoptosis marker tissue transglutaminase were measured. Flow cytometry was used to analyze the distribution through the different phases of the cell cycle (propidium iodide, PI) and the apoptotic cascade (Annexin V in combination with PI). All microchip materials, with the exception of Cu, appeared to be suitable for HL60 cells, showing a ratio apoptosis/proliferation (R(ap)) comparable to materials used in conventional cell culture (polystyrene). These results were confirmed with cell cycle analysis and apoptosis studies. Precoating the microchip material surfaces with serum favor the proliferation, as demonstrated by a lower R(ap) as compared to uncoated surfaces. The Cu-coated surface appeared to be toxic for HL60 cells, showing over 90% decreased viability within 24 h. From these results, it can be concluded that the chosen protocol is suitable for selection of the cell culture material, and that the most commonly used microchip materials are compatible with HL60 culturing.

  7. Development of a microchip Europium nanoparticle immunoassay for sensitive point-of-care HIV detection.

    PubMed

    Liu, Jikun; Du, Bingchen; Zhang, Panhe; Haleyurgirisetty, Mohan; Zhao, Jiangqin; Ragupathy, Viswanath; Lee, Sherwin; DeVoe, Don L; Hewlett, Indira K

    2014-11-15

    Rapid, sensitive and specific diagnostic assays play an indispensable role in determination of HIV infection stages and evaluation of efficacy of antiretroviral therapy. Recently, our laboratory developed a sensitive Europium nanoparticle-based microtiter-plate immunoassay capable of detecting target analytes at subpicogram per milliliter levels without the use of catalytic enzymes and signal amplification processes. Encouraged by its sensitivity and simplicity, we continued to miniaturize this assay to a microchip platform for the purpose of converting the benchtop assay technique to a point-of-care test. It was found that detection capability of the microchip platform could be readily improved using Europium nanoparticle probes. We were able to routinely detect 5 pg/mL (4.6 attomoles) of HIV-1 p24 antigen at a signal-to-blank ratio of 1.5, a sensitivity level reasonably close to that of microtiter-plate Europium nanoparticle assay. Meanwhile, use of the microchip platform effectively reduced sample/reagent consumption 4.5 fold and shortened total assay time 2 fold in comparison with microtiter plate assays. Complex matrix substance in plasma negatively affected the microchip assays and the effects could be minimized by diluting the samples before loading. With further improvements in sensitivity, reproducibility, usability, assay process simplification, and incorporation of portable time-resolved fluorescence reader, Europium nanoparticle immunoassay technology could be adapted to meet the challenges of point-of-care diagnosis of HIV or other health-threatening pathogens at bedside or in resource-limited settings.

  8. Saturn's Spectacular Ring System

    NASA Technical Reports Server (NTRS)

    Lissauer, Jack J.; DeVincenzi, Donald (Technical Monitor)

    2001-01-01

    Saturn's beautiful rings have fascinated astronomers since they were first observed by Galileo in 1610. The main rings consist of solid particles mostly in the 1 cm - 10 m range, composed primarily of water ice. The ring disk is exceptionally thin - the typical local thickness of the bright rings is tens of meters, whereas the diameter of the main rings is 250,000 km! The main rings exhibit substantial radial variations "ringlets", many of which are actively maintained via gravitational perturbations from Saturn's moons. Exterior to the main rings lie tenuous dust rings, which have little mass but occupy a very large volume of space. This seminar will emphasize the physics of ring-moon interactions, recent advances in our understanding of various aspects of the rings obtained from observations taken during 1995 when the rings appeared edge-on to the Earth and then to the Sun, and observations in subsequent years from HST.

  9. Trap style influences wild pig behavior and trapping success

    USGS Publications Warehouse

    Williams, B.L.; Holtfreter, R.W.; Ditchkoff, S.S.; Grand, J.B.

    2011-01-01

    Despite the efforts of many natural resource professionals, wild pig (Sus scrofa) populations are expanding in many areas of the world. Although many creative techniques for controlling pig populations are being explored, trapping has been and still is themost commonly usedmethod of population control formany public and private land managers. We conducted an observational study to examine the efficiency of 2 frequently used trap styles: a small, portable box-style trap and a larger, semi-permanent, corral-style trap.We used game cameras to examine patterns of trap entry by wild pigs around each style of trap, and we conducted a trapping session to compare trapping success between trap styles. Adult female and juvenile wild pigs entered both styles of trap more readily than did adult males, and adult males seemed particularly averse to entering box traps. Less than 10% of adult male visits to box traps resulted in entries, easily the least percentage of any class at any style of trap. Adult females entered corral traps approximately 2.2 times more often per visit than box traps and re-entered corral traps >2 times more frequently. Juveniles entered and reentered both box and corral traps at similar rates. Overall (all-class) entry-per-visit rates at corral traps (0.71) were nearly double that of box traps (0.37). Subsequent trapping data supported these preliminary entry data; the capture rate for corral traps was >4 times that of box traps. Our data suggest that corral traps are temporally and economically superior to box traps with respect to efficiency; that is, corral traps effectively trap more pigs per trap night at a lower cost per pig than do box traps. ?? 2011 The Wildlife Society.

  10. Fabrication of an octadecylated silica monolith inside a glass microchip for protein enrichment.

    PubMed

    Alzahrani, Eman; Welham, Kevin

    2012-10-21

    Silica-based monolithic materials have shown great promise for use as sorbent materials due to their large surface area and bimodal pore size distribution. In this paper, a new process for the fabrication of a silica-based monolith inside a glass microchip and its modification with octadecylsilyl ligands was successfully developed for use in the microchip-based solid phase extraction of proteins. Monolithic porous silica without cracks was prepared by a sol-gel process, followed by placement of the monolithic silica disk inside the extraction chamber in the base plate of the microchip. The two plates of the glass microchip were then thermally bonded at 575 °C for 3 hours. The silica-based monolith was not affected by the thermal bonding of the two plates of the microchip. This process completely avoids the problem of shrinkage in the silica skeleton during preparation. The monolithic silica disk inside the glass microchip was subsequently modified with octadecylsilyl (C(18)) moieties for increased protein binding capacity. The performance of the microchip was evaluated using the extraction of six proteins varying in molecular weight and isoelectric point, namely insulin, cytochrome C, lysozyme, myoglobin, β-lactoglobulin, and hemoglobin at a concentration of 60 μM. The standard protein was mixed with a double concentration of the detergent 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS). The results show that the octadecylated silica monolith was permeable, has the ability to remove impurities, and achieved a high extraction recovery of the proteins (94.8-99.7%) compared with conventional octadecylated silica particles (48.3-91.3%). The chip-to-chip reproducibility was assessed by calculating the relative standard deviations (RSDs) for the six proteins during extraction. The intra-batch and inter-batch RSDs were in the range of 2.0-4.5% and 2.9-6.4%, respectively. This new microfluidic device for protein extraction may find an application in

  11. Ecological and evolutionary traps

    USGS Publications Warehouse

    Schlaepfer, Martin A.; Runge, M.C.; Sherman, P.W.

    2002-01-01

    Organisms often rely on environmental cues to make behavioral and life-history decisions. However, in environments that have been altered suddenly by humans, formerly reliable cues might no longer be associated with adaptive outcomes. In such cases, organisms can become 'trapped' by their evolutionary responses to the cues and experience reduced survival or reproduction. Ecological traps occur when organisms make poor habitat choices based on cues that correlated formerly with habitat quality. Ecological traps are part of a broader phenomenon, evolutionary traps, involving a dissociation between cues that organisms use to make any behavioral or life-history decision and outcomes normally associated with that decision. A trap can lead to extinction if a population falls below a critical size threshold before adaptation to the novel environment occurs. Conservation and management protocols must be designed in light of, rather than in spite of, the behavioral mechanisms and evolutionary history of populations and species to avoid 'trapping' them.

  12. Microfabricated ion trap array

    DOEpatents

    Blain, Matthew G.; Fleming, James G.

    2006-12-26

    A microfabricated ion trap array, comprising a plurality of ion traps having an inner radius of order one micron, can be fabricated using surface micromachining techniques and materials known to the integrated circuits manufacturing and microelectromechanical systems industries. Micromachining methods enable batch fabrication, reduced manufacturing costs, dimensional and positional precision, and monolithic integration of massive arrays of ion traps with microscale ion generation and detection devices. Massive arraying enables the microscale ion traps to retain the resolution, sensitivity, and mass range advantages necessary for high chemical selectivity. The reduced electrode voltage enables integration of the microfabricated ion trap array with on-chip circuit-based rf operation and detection electronics (i.e., cell phone electronics). Therefore, the full performance advantages of the microfabricated ion trap array can be realized in truly field portable, handheld microanalysis systems.

  13. Migration of Small Moons in Saturn's Rings

    NASA Astrophysics Data System (ADS)

    Bromley, Benjamin C.; Kenyon, Scott J.

    2013-02-01

    The motions of small moons through Saturn's rings provide excellent tests of radial migration models. In theory, torque exchange between these moons and ring particles leads to radial drift. We predict that moons with Hill radii r H ~ 2-24 km should migrate through the A ring in 1000 yr. In this size range, moons orbiting in an empty gap or in a full ring eventually migrate at the same rate. Smaller moons or moonlets—such as the propellers—are trapped by diffusion of disk material into corotating orbits, creating inertial drag. Larger moons—such as Pan or Atlas—do not migrate because of their own inertia. Fast migration of 2-24 km moons should eliminate intermediate-size bodies from the A ring and may be responsible for the observed large-radius cutoff of r H ~ 1-2 km in the size distribution of the A ring's propeller moonlets. Although the presence of Daphnis (r H ≈ 5 km) inside the Keeler gap challenges this scenario, numerical simulations demonstrate that orbital resonances and stirring by distant, larger moons (e.g., Mimas) may be important factors. For Daphnis, stirring by distant moons seems the most promising mechanism to halt fast migration. Alternatively, Daphnis may be a recent addition to the ring that is settling into a low inclination orbit in ~103 yr prior to a phase of rapid migration. We provide predictions of observational constraints required to discriminate among possible scenarios for Daphnis.

  14. Neutral atom traps.

    SciTech Connect

    Pack, Michael Vern

    2008-12-01

    This report describes progress in designing a neutral atom trap capable of trapping sub millikelvin atom in a magnetic trap and shuttling the atoms across the atom chip from a collection area to an optical cavity. The numerical simulation and atom chip design are discussed. Also, discussed are preliminary calculations of quantum noise sources in Kerr nonlinear optics measurements based on electromagnetically induced transparency. These types of measurements may be important for quantum nondemolition measurements at the few photon limit.

  15. Evaluating steam trap performance

    SciTech Connect

    Fuller, N.Y.

    1985-08-08

    This paper presents a method for evaluating the performance level of steam traps by preparing an economic analysis of several types to determine the equivalent uniform annual cost. A series of tests on steam traps supplied by six manufacturers provided data for determining the relative efficiencies of each unit. The comparison was made using a program developed for the Texas Instruments T1-59 programmable calculator to evaluate overall steam trap economics.

  16. Air-stable supported membranes for single-cell cytometry on PDMS microchips.

    PubMed

    Phillips, K Scott; Kang, Kyung Mo; Licata, Louise; Allbritton, Nancy L

    2010-04-07

    Protein-reinforced supported bilayer membranes (rSBMs) composed of phosphatidylcholine (PC), biotin-PE and Neutravidin were used to coat hybrid microchips composed of polydimethylsiloxane (PDMS) and glass. Since the coatings required a freshly oxidized, hydrophilic substrate, a novel method to rapidly connect reservoirs using plasma oxidation was first developed and found to support up to 5.2 N cm(-2) (1.5 N) pull-off force. rSBMs were then assembled in the oxidized hydrophilic channels. The electroosmotic mobility (mu(eo)) of rSBM-coated channels was measured over a 3 h time to evaluate the stability of the coatings for microchip electrophoresis. rSBM-coated microchips with a simple cross-design had excellent properties for microchip separations, yielding efficiencies of up to 700,000 plates m(-1) for fluorescent dyes and peptides. The separation performance of rSBM and PC-coated channels was evaluated after repeatedly drying and rehydrating the channels. The separation efficiency of fluorescein on PC-coated devices decreased by 40% after one dehydration cycle and nearly 75% after 3 cycles. In contrast for rSBM-coated devices there was no significant change in the fluorescein efficiency until the third cycle (10% decreased efficiency). rSBM-coated channels were also markedly more stable when placed in a dehydrated state during long-term storage compared to PC-coated channels, and showed reduced chip failure and no reduction in performance for up to one month of dehydrated storage. Finally, rSBM-coated devices were used to perform single-cell cytometry. Microchips that had been dehydrated, stored two weeks, and rehydrated prior to use demonstrated similar performance to newly coated devices for the separation of fluorescein and carboxyfluorescein from single cells. Thus rSBM-coated devices were rugged withstanding electric fields, prolonged storage under dehydrated conditions, and biofouling by cellular constituents while maintaining excellent separation

  17. Air-Stable Supported Membranes for Single Cell Cytometry on PDMS Microchips

    PubMed Central

    Phillips, K. Scott; Kang, Kyung Mo; Licata, Louise

    2010-01-01

    Protein reinforced supported bilayer membranes (rSBMs) composed of phosphatidyl choline (PC), biotin-PE and Neutravidin were used to coat hybrid microchips composed of polydimethylsiloxane (PDMS) and glass. Since the coatings required a freshly oxidized, hydrophilic substrate, a novel method to rapidly connect reservoirs using plasma oxidation was first developed and found to support up to 5.2 N/cm2 (1.5 N) pull-off force. rSBMs were then assembled in the oxidized hydrophilic channels. The electroosmotic mobility (μeo) of rSBM-coated channels was measured over a 3 h time to evaluate the stability of the coatings for microchip electrophoresis. rSBM-coated microchips with a simple cross design had excellent properties for microchip separations, yielding efficiencies of up to 700,000 plates/m for fluorescent dyes and peptides. The separation performance of rSBM and PC-coated channels was evaluated after repeatedly drying and rehydrating the channels. The separation efficiency of fluorescein on PC-coated devices decreased by 40% after one dehydration cycle and nearly 75% after 3 cycles. In contrast for rSBM-coated devices there was no significant change in the fluorescein efficiency until the third cycle (10% decreased efficiency). rSBM-coated channels were also markedly more stable when placed in a dehydrated state during long-term storage compared to PC-coated channels, and showed reduced chip failure and no reduction in performance for up to one month of dehydrated storage. Finally, rSBM-coated devices were used to perform single-cell cytometry. Microchips that had been dehydrated, stored two weeks, and rehydrated prior to use demonstrated similar performance to newly coated devices for the separation of fluorescein and carboxyfluorescein from single cells. Thus rSBM-coated devices were rugged- withstanding electric fields, prolonged storage under dehydrated conditions, and biofouling by cellular constituents while maintaining excellent separation performance. PMID

  18. Dynamic solid phase DNA extraction and PCR amplification in polyester-toner based microchip.

    PubMed

    Duarte, Gabriela R M; Price, Carol W; Augustine, Brian H; Carrilho, Emanuel; Landers, James P

    2011-07-01

    A variety of substrates have been used for fabrication of microchips for DNA extraction, PCR amplification, and DNA fragment separation, including the more conventional glass and silicon as well as alternative polymer-based materials. Polyester represents one such polymer, and the laser-printing of toner onto polyester films has been shown to be effective for generating polyester-toner (PeT) microfluidic devices with channel depths on the order of tens of micrometers. Here, we describe a novel and simple process that allows for the production of multilayer, high aspect-ratio PeT microdevices with substantially larger channel depths. This innovative process utilizes a CO(2) laser to create the microchannel in polyester sheets containing a uniform layer of printed toner, and multilayer devices can easily be constructed by sandwiching the channel layer between uncoated cover sheets of polyester containing precut access holes. The process allows the fabrication of deep channels, with ~270 μm, and we demonstrate the effectiveness of multilayer PeT microchips for dynamic solid phase extraction (dSPE) and PCR amplification. With the former, we found that (i) more than 65% of DNA from 0.6 μL of blood was recovered, (ii) the resultant DNA was concentrated to greater than 3 ng/μL (which was better than other chip-based extraction methods), and (iii) the DNA recovered was compatible with downstream microchip-based PCR amplification. Illustrative of the compatibility of PeT microchips with the PCR process, the successful amplification of a 520 bp fragment of λ-phage DNA in a conventional thermocycler is shown. The ability to handle the diverse chemistries associated with DNA purification and extraction is a testimony to the potential utility of PeT microchips beyond separations and presents a promising new disposable platform for genetic analysis that is low cost and easy to fabricate.

  19. Stirling engine piston ring

    DOEpatents

    Howarth, Roy B.

    1983-01-01

    A piston ring design for a Stirling engine wherein the contact pressure between the piston and the cylinder is maintained at a uniform level, independent of engine conditions through a balancing of the pressure exerted upon the ring's surface and thereby allowing the contact pressure on the ring to be predetermined through the use of a preloaded expander ring.

  20. Birth Control Ring

    MedlinePlus

    ... Loss Surgery? A Week of Healthy Breakfasts Shyness Birth Control Ring KidsHealth > For Teens > Birth Control Ring Print A A A What's in this ... español Anillo vaginal anticonceptivo What Is It? The birth control ring is a soft, flexible, doughnut-shaped ring ...

  1. Steam Trap Users’ Guide,

    DTIC Science & Technology

    1985-04-01

    traps do not work well in a system where the condensate can back against the operating mechanism of the trap and open it when there is no condensate flow ...a flow through the trap. h. Float and thermostatic traps are widely used in low pressure heating 0 systems . If they are properly installed below the... system or trap problem. * Blowdown strainer. SOUND CHECK HOT TRAPS: • Listen to trap operate. * Check for continuous flow : - low pitch condensate flow

  2. Beam properties of UVSOR storage ring

    SciTech Connect

    Kasuga, T.; Hasumoto, M.; Kinoshita, T.; Yonehara, H.

    1985-10-01

    UVSOR constructed at the IMS (Institute for Molecular Science) is an electron storage ring dedicated to synchrotron radiation research in molecular science and its related fields. The first beam was stored on 10th Nov. in 1983. From that time on, efforts have been devoted to improvement of the performance of the ring. During the accelerator studies, some inconvenient phenomena were found. One of the big problems is ion trapping effect. Trapped ions change the operating point and enhance the coupling between horizontal and vertical oscillations. As a result, the beam height is enlarged considerably at high beam current. The beam is shaken slightly in the vertical plane and the electrostatic clearing field is applied to solve this problem. The bunch length is somewhat longer than the expected value. This effect is also a problem to be solved.

  3. Drift due to viscous vortex rings

    NASA Astrophysics Data System (ADS)

    Morrell, Thomas; Spagnolie, Saverio; Thiffeault, Jean-Luc

    2016-11-01

    Biomixing is the study of fluid mixing due to swimming organisms. While large organisms typically produce turbulent flows in their wake, small organisms produce less turbulent wakes; the main mechanism of mixing is the induced net particle displacement (drift). Several experiments have examined this drift for small jellyfish, which produce vortex rings that trap and transport a fair amount of fluid. Inviscid theory implies infinite particle displacements for the trapped fluid, so the effect of viscosity must be included to understand the damping of real vortex motion. We use a model viscous vortex ring to compute particle displacements and other relevant quantities, such as the integrated moments of the displacement. Fluid entrainment at the tail end of a growing vortex 'envelope' is found to play an important role in the total fluid transport and drift. Partially supported by NSF Grant DMS-1109315.

  4. New Dust Belts of Uranus: One Ring, Two Ring, Red Ring, Blue Ring

    SciTech Connect

    de Pater, I; Hammel, H B; Gibbard, S G; Showalter, M R

    2006-02-02

    We compare near-infrared observations of the recently discovered outer rings of Uranus with HST results. We find that the inner ring, R/2003 U 2, is red, whereas the outer ring, R/2003 U 1, is very blue. Blue is an unusual color for rings; Saturn's enigmatic E ring is the only other known example. By analogy to the E ring, R/2003 U 1 is probably produced via impacts into the embedded moon Mab, which apparently orbits at a location where non-gravitational perturbations favor the survival and spreading of sub-micron sized dust. R/2003 U 2 more closely resembles Saturn's G ring.

  5. Hydrodynamic injection on electrophoresis microchips using an electronic micropipette.

    PubMed

    Gabriel, Ellen F M; Dos Santos, Rodrigo A; Lobo-Júnior, Eulício O; Rezende, Kariolanda C A; Coltro, Wendell K T

    2017-01-01

    Here we report for the first time the use of an electronic micropipette as hydrodynamic (HD) injector for microchip electrophoresis (ME) devices. The micropipette was directly coupled to a PDMS device, which had been fabricated in a simple cross format with two auxiliary channels for sample volume splitting. Sample flow during the injection procedure was controlled in automatic dispenser mode using a volume of 0.6µL. Channel width and device configuration were optimized and the best results were achieved using a simple cross layout containing two auxiliary channels with 300µm width for sample splitting. The performance of the HD injector was evaluated using a model mixture of high-mobility cationic species. The results obtained were compared to the data obtained via electrokinetic (EK) injection. Overall, the HD provided better analytical performance in terms of resolution and injection-to-injection repeatability. The relative standard deviation (RSD) values for peak intensities were lower than 5% (n=10) when the micropipette was employed. In comparison with EK injection, the use of the proposed HD injector revealed an unbiased profile for a mixture containing K(+) and Li(+)(300 µmol L(-1) each) over various buffer concentrations. For EK injection, the peak areas decreased from 2.92 ± 0.20-0.72 ± 0.14Vs for K(+) and from 1.30 ± 0.10-0.38 ± 0.10Vs for Li(+) when the running buffer increased from 20 to 50mmolL(-1). For HD injection, the peak areas for K(+) and Li(+) exhibited average values of 2.48±0.07 and 2.10±0.06Vs, respectively. The limits of detection (LDs) for K(+), Na(+) and Li(+) ranged from 18 to 23µmolL(-1). HD injection through an electronic micropipette allows to automatically dispense a bias-free amount of sample inside microchannels with acceptable repeatability. The proposed approach also exhibited instrumental simplicity, portability and minimal microfabrication requirements.

  6. R&D 100, 2016: T-Quake – Quantum-Mechanical Transmitter/Receiver Microchip

    ScienceCinema

    Tauke-Pedretti, Anna; Camacho, Ryan; Thayer, Gayle

    2016-12-14

    Applying advanced microfabrication techniques and innovative microdesign, the Sandia Enabled Communications and Authentication Network (SECANT) team has designed and produced photonic microchips capable of sending, receiving, and processing quantum signals for applications in cyber and physical security.

  7. Characterization of low viscosity polymer solutions for microchip electrophoresis of non-denatured proteins on plastic chips.

    PubMed

    Yasui, Takao; Reza Mohamadi, Mohamad; Kaji, Noritada; Okamoto, Yukihiro; Tokeshi, Manabu; Baba, Yoshinobu

    2011-12-01

    In this paper, we study characteristics of polymers (methylcellulose, hypromellose ((hydroxypropyl)methyl cellulose), poly(vinylpyrrolidone), and poly(vinyl alcohol)) with different chemical structures for microchip electrophoresis of non-denatured protein samples in a plastic microchip made of poly(methyl methacrylate) (PMMA). Coating efficiency of these polymers for controlling protein adsorption onto the channel surface of the plastic microchip, wettability of the PMMA surface, and electroosmotic flow in the PMMA microchannels in the presence of these polymers were compared. Also relative electrophoretic mobility of protein samples in solutions of these polymers was studied. We showed that when using low polymer concentrations (lower than the polymer entanglement point) where the sieving effect is substantially negligible, the interaction of the samples with the polymer affected the electrophoretic mobility of the samples. This effect can be used for achieving better resolution in microchip electrophoresis of protein samples.

  8. A Novel Protocol to Analyze Short- and Long-Chain Fatty Acids Using Nonaqueous Microchip Capillary Electrophoresis

    NASA Technical Reports Server (NTRS)

    Cable, M. L.; Stockton, A. M.; Mora, Maria F; Willis, P. A.

    2013-01-01

    We propose a new protocol to identify and quantify both short- and long-chain saturated fatty acids in samples of astrobiological interest using non-aqueous microchip capillary electrophoresis (micronNACE) with laser induced fluorescence (LIF).

  9. Optical trapping of nanoparticles.

    PubMed

    Bergeron, Jarrah; Zehtabi-Oskuie, Ana; Ghaffari, Saeedeh; Pang, Yuanjie; Gordon, Reuven

    2013-01-15

    Optical trapping is a technique for immobilizing and manipulating small objects in a gentle way using light, and it has been widely applied in trapping and manipulating small biological particles. Ashkin and co-workers first demonstrated optical tweezers using a single focused beam. The single beam trap can be described accurately using the perturbative gradient force formulation in the case of small Rayleigh regime particles. In the perturbative regime, the optical power required for trapping a particle scales as the inverse fourth power of the particle size. High optical powers can damage dielectric particles and cause heating. For instance, trapped latex spheres of 109 nm in diameter were destroyed by a 15 mW beam in 25 sec, which has serious implications for biological matter. A self-induced back-action (SIBA) optical trapping was proposed to trap 50 nm polystyrene spheres in the non-perturbative regime. In a non-perturbative regime, even a small particle with little permittivity contrast to the background can influence significantly the ambient electromagnetic field and induce a large optical force. As a particle enters an illuminated aperture, light transmission increases dramatically because of dielectric loading. If the particle attempts to leave the aperture, decreased transmission causes a change in momentum outwards from the hole and, by Newton's Third Law, results in a force on the particle inwards into the hole, trapping the particle. The light transmission can be monitored; hence, the trap can become a sensor. The SIBA trapping technique can be further improved by using a double-nanohole structure. The double-nanohole structure has been shown to give a strong local field enhancement. Between the two sharp tips of the double-nanohole, a small particle can cause a large change in optical transmission, thereby inducing a large optical force. As a result, smaller nanoparticles can be trapped, such as 12 nm silicate spheres and 3.4 nm hydrodynamic radius

  10. Nonlinear integrable ion traps

    SciTech Connect

    Nagaitsev, S.; Danilov, V.; /SNS Project, Oak Ridge

    2011-10-01

    Quadrupole ion traps can be transformed into nonlinear traps with integrable motion by adding special electrostatic potentials. This can be done with both stationary potentials (electrostatic plus a uniform magnetic field) and with time-dependent electric potentials. These potentials are chosen such that the single particle Hamilton-Jacobi equations of motion are separable in some coordinate systems. The electrostatic potentials have several free adjustable parameters allowing for a quadrupole trap to be transformed into, for example, a double-well or a toroidal-well system. The particle motion remains regular, non-chaotic, integrable in quadratures, and stable for a wide range of parameters. We present two examples of how to realize such a system in case of a time-independent (the Penning trap) as well as a time-dependent (the Paul trap) configuration.

  11. Hydrogel-based protein and oligonucleotide microchips on metal-coated surfaces: enhancement of fluorescence and optimization of immunoassay.

    PubMed

    Zubtsova, Zh I; Zubtsov, D A; Savvateeva, E N; Stomakhin, A A; Chechetkin, V R; Zasedatelev, A S; Rubina, A Yu

    2009-10-26

    Manufacturing of hydrogel-based microchips on metal-coated substrates significantly enhances fluorescent signals upon binding of labeled target molecules. This observation holds true for both oligonucleotide and protein microchips. When Cy5 is used as fluorophore, this enhancement is 8-10-fold in hemispherical gel elements and 4-5-fold in flattened gel pads, as compared with similar microchips manufactured on uncoated glass slides. The effect also depends on the hydrophobicity of metal-coated substrate and on the presence of a layer of liquid over the gel pads. The extent of enhancement is insensitive to the nature of formed complexes and immobilized probes and remains linear within a wide range of fluorescence intensities. Manufacturing of gel-based protein microarrays on metal-coated substrates improves their sensitivity using the same incubation time for immunoassay. Sandwich immunoassay using these microchips allows shortening the incubation time without loss of sensitivity. Unlike microchips with probes immobilized directly on a surface, for which the plasmon mechanism is considered responsible for metal-enhanced fluorescence, the enhancement effect observed using hydrogel-based microchips on metal-coated substrates might be explained within the framework of geometric optics.

  12. Comparison of body temperature readings between an implantable microchip and a cloacal probe in lorikeets (Trichoglossus haematodus sp.).

    PubMed

    Hoskinson, Christine; McCain, Stephanie; Allender, Matthew C

    2014-01-01

    Body temperature readings can be a useful diagnostic tool for identifying the presence of subclinical disease. Traditionally, rectal or cloacal thermometry has been used to obtain body temperatures. The use of implantable microchips to obtain these temperatures has been studied in a variety of animals, but not yet in avian species. Initially, timepoint one (T₁), nine lorikeets were anesthetized via facemask induction with 5% isoflurane and maintained at 2-3% for microchip placement and body temperature data collection. Body temperature was measured at 0 and 2 min post-anesthetic induction both cloacally, using a Cardell veterinary monitor and also via implantable microchip, utilizing a universal scanner. On two more occasions, timepoints two and three (T₂, T₃), the same nine lorikeets were manually restrained to obtain body temperature readings both cloacally and via microchip, again at minutes 0 and 2. There was no statistical difference between body temperatures, for both methods, at T₁. Microchip temperatures were statistically different than cloacal temperatures at T₂ and T₃. Body temperatures at T₁, were statistically different from those obtained at T₂ and T₃ for both methods. Additional studies are warranted to verify the accuracy of microchip core body temperature readings in avian species.

  13. Side-by-side comparison of disposable microchips with commercial capillary cartridges for application in capillary isoelectric focusing with whole column imaging detection.

    PubMed

    Liu, Zhen; Ou, Junjie; Samy, Razim; Glawdel, Tomasz; Huang, Tiemin; Ren, Carolyn L; Pawliszyn, Janusz

    2008-10-01

    Simple-structured, well-functioned disposable poly(dimethylsiloxane) (PDMS) microchips were developed for capillary isoelectric focusing with whole column imaging detection (CIEF-WCID). Side-by-side comparison of the developed microchips with well-established commercial capillary cartridges demonstrated that the disposable microchips have comparable performance as well as advantages such as absence of lens effect and possibility of high-aspect-ratio accompanied with a dramatic reduction in cost.

  14. Quantized levitation states of superconducting multiple-ring systems

    SciTech Connect

    Haley, S.B.; Fink, H.J.

    1996-02-01

    The quantized levitation, trapped, and suspension states of a magnetic microsphere held in equilibrium by two fixed superconducting (SC) microrings are calculated by minimizing the free energy of the system. Each state is a discrete function of two independent fluxoid quantum numbers of the rings. When the radii of the SC rings are of the same order as the Ginzburg-Landau coherence length {xi}({ital T}), the system exhibits a small set of gravity and temperature-dependent levels. The levels of a weakly magnetized particle are sensitive functions of the gravitational field, indicating potential application as an accelerometer, and for trapping small magnetic particles in outer space or on Earth. The equilibrium states of a SC ring levitated by another SC ring are also calculated. {copyright} {ital 1996 The American Physical Society.}

  15. Effects of abscisic acid and nitric oxide on trap formation and trapping of nematodes by the fungus Drechslerella stenobrocha AS6.1.

    PubMed

    Xu, Ling-Ling; Lai, Yi-Ling; Wang, Lin; Liu, Xing-Zhong

    2011-02-01

    The in vitro effects of abscisic acid (ABA) and nitric oxide (NO) on the nematode-trapping fungus Drechslerella stenobrocha AS6.1 were examined. The average number of traps (constricting rings) per colony and the percentage of nematodes (Caenorhabditis elegans) trapped were greatly increased by addition of ABA but greatly suppressed by addition of sodium nitroprusside (SNP, an NO donor) to corn meal agar. The suppressive effect of SNP was not negated by addition of an NO synthase competitive inhibitor (l-naphthylacetic acid, L-NNA) or an NO-specific scavenger [2-(4-carboxyphenyl)-4,4, 5,5-tetramethylimidazoline-1-oxyl-3-oxide, cPTIO]. When added without SNP, however, L-NNA and cPTIO caused moderate increases in trap number and trapping. The results indicate that the trap formation and nematode-trapping ability of D. stenobrocha were enhanced by ABA but decreased by exogenous NO.

  16. Jupiter's Main Ring/Ring Halo

    NASA Technical Reports Server (NTRS)

    1997-01-01

    A mosaic of four images taken through the clear filter (610 nanometers) of the solid state imaging (CCD) system aboard NASA's Galileo spacecraft on November 8, 1996, at a resolution of approximately 46 kilometers (28.5 miles) per picture element (pixel) along Jupiter's rings. Because the spacecraft was only about 0.5 degrees above the ring plane, the image is highly foreshortened in the vertical direction. The images were obtained when Galileo was in Jupiter's shadow, peering back toward the Sun; the ring was approximately 2.3 million kilometers (1.4 million miles) away. The arc on the far right of the image is produced when sunlight is scattered by small particles comprising Jupiter's upper atmospheric haze. The ring also efficiently scatters light, indicating that much of its brightness is due to particles that are microns or less in diameter. Such small particles are believed to have human-scale lifetimes, i.e., very brief compared to the solar system's age.

    Jupiter's ring system is composed of three parts - - a flat main ring, a lenticular halo interior to the main ring, and the gossamer ring, outside the main ring. The near and far arms of Jupiter's main ring extend horizontally across the mosaic, joining together at the ring's ansa, on the figure's far left side. The near arm of the ring appears to be abruptly truncated close to the planet, at the point where it passes into Jupiter's shadow. Some radial structure is barely visible across the ring's ansa (top image). A faint mist of particles can be seen above and below the main rings. This vertically extended 'halo' is unusual in planetary rings, and is probably caused by electromagnetic forces pushing the smallest grains out of the ring plane. Because of shadowing, the halo is not visible close to Jupiter in the lower right part of the mosaic. To accentuate faint features in the bottom image of the ring halo, different brightnesses are shown through color. Brightest features are white or yellow and the

  17. Bose-Einstein condensation in large time-averaged optical ring potentials

    NASA Astrophysics Data System (ADS)

    Bell, Thomas A.; Glidden, Jake A. P.; Humbert, Leif; Bromley, Michael W. J.; Haine, Simon A.; Davis, Matthew J.; Neely, Tyler W.; Baker, Mark A.; Rubinsztein-Dunlop, Halina

    2016-03-01

    Interferometric measurements with matter waves are established techniques for sensitive gravimetry, rotation sensing, and measurement of surface interactions, but compact interferometers will require techniques based on trapped geometries. In a step towards the realisation of matter wave interferometers in toroidal geometries, we produce a large, smooth ring trap for Bose-Einstein condensates using rapidly scanned time-averaged dipole potentials. The trap potential is smoothed by using the atom distribution as input to an optical intensity correction algorithm. Smooth rings with a diameter up to 300 μm are demonstrated. We experimentally observe and simulate the dispersion of condensed atoms in the resulting potential, with good agreement serving as an indication of trap smoothness. Under time of flight expansion we observe low energy excitations in the ring, which serves to constrain the lower frequency limit of the scanned potential technique. The resulting ring potential will have applications as a waveguide for atom interferometry and studies of superfluidity.

  18. The source of Saturn's G ring.

    PubMed

    Hedman, Matthew M; Burns, Joseph A; Tiscareno, Matthew S; Porco, Carolyn C; Jones, Geraint H; Roussos, Elias; Krupp, Norbert; Paranicas, Chris; Kempf, Sascha

    2007-08-03

    The origin of Saturn's narrow G ring has been unclear. We show that it contains a bright arc located 167,495.6 +/- 1.3 km from Saturn's center. This longitudinally localized material is trapped in a 7:6 corotation eccentricity resonance with the satellite Mimas. The cameras aboard the Cassini spacecraft mainly observe small (1 to 10 micrometers) dust grains in this region, but a sharp decrease in the flux of energetic electrons measured near this arc requires that it also contain larger (centimeter- to meter-sized) bodies whose total mass is equivalent to that of a approximately 100-meter-wide ice-rich moonlet. Collisions into these bodies may generate dust, which subsequently drifts outward to populate the rest of the G ring. Thus, the entire G ring could be derived from an arc of debris held in a resonance with Mimas.

  19. Quadrupole ion traps.

    PubMed

    March, Raymond E

    2009-01-01

    The extraordinary story of the three-dimensional radiofrequency quadrupole ion trap, accompanied by a seemingly unintelligible theoretical treatment, is told in some detail because of the quite considerable degree of commercial success that quadrupole technology has achieved. The quadrupole ion trap, often used in conjunction with a quadrupole mass filter, remained a laboratory curiosity until 1979 when, at the American Society for Mass Spectrometry Conference in Seattle, George Stafford, Jr., of Finnigan Corp., learned of the Masters' study of Allison Armitage of a combined quadrupole ion trap/quadrupole mass filter instrument for the observation of electron impact and chemical ionization mass spectra of simple compounds eluting from a gas chromatograph. Stafford developed subsequently the mass-selective axial instability method for obtaining mass spectra from the quadrupole ion trap alone and, in 1983, Finnigan Corp. announced the first commercial quadrupole ion trap instrument as a detector for a gas chromatograph. In 1987, confinement of ions generated externally to the ion trap was demonstrated and, soon after, the new technique of electrospray ionization was shown to be compatible with the ion trap.

  20. Mode trap for absorbing transverse modes of an accelerated electron beam

    DOEpatents

    Chojnacki, E.P.

    1994-05-31

    A mode trap to trap and absorb transverse modes formed by a beam in a linear accelerator includes a waveguide having a multiplicity of electrically conductive (preferably copper) irises and rings, each iris and ring including an aperture, and the irises and rings being stacked in a side-by-side, alternating fashion such that the apertures of the irises and rings are concentrically aligned. An absorbing material layer such as a dielectric is embedded in each iris and ring, and this absorbing material layer encircles, but is circumferentially spaced from its respective aperture. Each iris and ring includes a plurality of circumferentially spaced slots around its aperture and extending radially out toward its absorbing material layer. 9 figs.

  1. Mode trap for absorbing transverse modes of an accelerated electron beam

    DOEpatents

    Chojnacki, Eric P.

    1994-01-01

    A mode trap to trap and absorb transverse modes formed by a beam in a linear accelerator includes a waveguide having a multiplicity of electrically conductive (preferably copper) irises and rings, each iris and ring including an aperture, and the irises and rings being stacked in a side-by-side, alternating fashion such that the apertures of the irises and rings are concentrically aligned. An absorbing material layer such as a dielectric is embedded in each iris and ring, and this absorbing material layer encircles, but is circumferentially spaced from its respective aperture. Each iris and ring includes a plurality of circumferentially spaced slots around its aperture and extending radially out toward its absorbing material layer.

  2. Stratigraphic traps 2

    SciTech Connect

    Not Available

    1991-01-01

    This volume contains studies of fields with traps that are mainly stratigraphic in nature. Structure plays a role in the traps of several fields, but overall, it is clear that the main trapping features with the group of fields in this volume are stratigraphic. The first six fields in this volume, Alabama Ferry, Rospo Mare, Walker Creek, Bindley, Lexington, and Newburg/South Westhope, have carbonate reservoirs. The latter two of these, Lexington and Newburg/South Westhope, also have sandstone reservoirs. The remaining fields, East Texas, East Clinton, Stockholm Southwest, Sorrento, Port Acres, and Lagoa Parda, have only sandstone reservoirs.

  3. ELECTRON TRAPPING IN WIGGLER AND QUADRUPOLE MAGNETS OF CESRTA

    SciTech Connect

    Wang, Lanfa; Huang, Xiaobiao; Pivi, Mauro; /SLAC

    2010-08-25

    The Cornell Electron Storage Ring (CESR) has been reconfigured as an ultra low emittance damping ring for use as a test accelerator (CesrTA) for International Linear Collider (ILC) damping ring R&D [1]. One of the primary goals of the CesrTA program is to investigate the interaction of the electron cloud with low emittance positron beam to explore methods to suppress the electron cloud, develop suitable advanced instrumentation required for these experimental studies and benchmark predictions by simulation codes. This paper reports the simulation of the electron-cloud formation in the wiggler and quadrupole magnets using the 3D code CLOUDLAND. We found that electrons can be trapped with long lifetime in a quadrupole magnet due to the mirror field trapping mechanism and photoelectrons produced in the wiggler zero field zone have long lifetime due to their complicated trajectory.

  4. The 1.7 kilogram microchip: energy and material use in the production of semiconductor devices.

    PubMed

    Williams, Eric D; Ayres, Robert U; Heller, Miriam

    2002-12-15

    The scale of environmental impacts associated with the manufacture of microchips is characterized through analysis of material and energy inputs into processes in the production chain. The total weight of secondary fossil fuel and chemical inputs to produce and use a single 2-gram 32MB DRAM chip are estimated at 1600 g and 72 g, respectively. Use of water and elemental gases (mainly N2) in the fabrication stage are 32,000 and 700 g per chip, respectively. The production chain yielding silicon wafers from quartz uses 160 times the energy required for typical silicon, indicating that purification to semiconductor grade materials is energy intensive. Due to its extremely low-entropy, organized structure, the materials intensity of a microchip is orders of magnitude higher than that of "traditional" goods. Future analysis of semiconductor and other low entropy high-tech goods needs to include the use of secondary materials, especially for purification.

  5. A real time affinity biosensor on an insulated polymer using electric impedance spectroscopy in dielectric microchips.

    PubMed

    Kechadi, Mohammed; Sotta, Bruno; Chaal, Lila; Tribollet, Bernard; Gamby, Jean

    2014-06-21

    This paper presents development of real time monitoring of binding events on flexible plastic in microchips. Two planar carbon microelectrodes are integrated into an insulated polyethylene terephthalate microchip without direct electrical contact with the solution in the microchannel. It has been possible to probe the electric impedance changes through the interface constituted by the microelectrode/PET microchannel/solution when a biomolecular interaction takes place on the polymer surface. This new transduction for biosensing was demonstrated for the molecular recognition of BSA immobilized on the polymer microchannel surface using the corresponding rabbit anti-BSA antibodies as an analyte in the flow microchannel at the nanomolar range concentration. The equilibrium association constant was determined for the affinity reaction between both ligands and was obtained equal to 5 × 10(7) M(-1). The promising results obtained with this new device make it a competitive biosensor.

  6. Scalable gene synthesis by selective amplification of DNA pools from high-fidelity microchips.

    PubMed

    Kosuri, Sriram; Eroshenko, Nikolai; Leproust, Emily M; Super, Michael; Way, Jeffrey; Li, Jin Billy; Church, George M

    2010-12-01

    Development of cheap, high-throughput and reliable gene synthesis methods will broadly stimulate progress in biology and biotechnology. Currently, the reliance on column-synthesized oligonucleotides as a source of DNA limits further cost reductions in gene synthesis. Oligonucleotides from DNA microchips can reduce costs by at least an order of magnitude, yet efforts to scale their use have been largely unsuccessful owing to the high error rates and complexity of the oligonucleotide mixtures. Here we use high-fidelity DNA microchips, selective oligonucleotide pool amplification, optimized gene assembly protocols and enzymatic error correction to develop a method for highly parallel gene synthesis. We tested our approach by assembling 47 genes, including 42 challenging therapeutic antibody sequences, encoding a total of ∼35 kilobase pairs of DNA. These assemblies were performed from a complex background containing 13,000 oligonucleotides encoding ∼2.5 megabases of DNA, which is at least 50 times larger than in previously published attempts.

  7. Gold nanodome-patterned microchips for intracellular surface-enhanced Raman spectroscopy.

    PubMed

    Wuytens, Pieter C; Subramanian, Ananth Z; De Vos, Winnok H; Skirtach, Andre G; Baets, Roel

    2015-12-21

    While top-down substrates for surface-enhanced Raman spectroscopy (SERS) offer outstanding control and reproducibility of the gold nanopatterns and their related localized surface plasmon resonance, intracellular SERS experiments heavily rely on gold nanoparticles. These nanoparticles often result in varying and uncontrollable enhancement factors. Here we demonstrate the use of top-down gold-nanostructured microchips for intracellular sensing. We develop a tunable and reproducible fabrication scheme for these microchips. Furthermore we observe the intracellular uptake of these structures, and find no immediate influence on cell viability. Finally, we perform a proof-of-concept intracellular SERS experiment by the label-free detection of extraneous molecules. By bringing top-down SERS substrates to the intracellular world, we set an important step towards time-dependent and quantitative intracellular SERS.

  8. Quality assurance of monoclonal antibody pharmaceuticals based on their charge variants using microchip isoelectric focusing method.

    PubMed

    Kinoshita, Mitsuhiro; Nakatsuji, Yuki; Suzuki, Shigeo; Hayakawa, Takao; Kakehi, Kazuaki

    2013-09-27

    Monoclonal antibody (mAb) pharmaceuticals are much more complex than small-molecule drugs. Such complex characteristics raise challenging questions for regulatory evaluation. Although heterogeneity in mAbs based on their charge variants has been mainly evaluated using gel-based isoelectric focusing (IEF) method, recent development in capillary electrophoresis and microchip electrophoresis has made it possible to assure their heterogeneities in more easy and rapid manner. In the present paper, we customized the imaged microchip isoelectric focusing (mIEF) for the analysis of mAbs, and compared the customized version with the conventional capillary isoelectric focusing (cIEF) method, and found that mIEF has much higher performance in operations, and its resolving powers are comparable with those obtained by cIEF.

  9. Sub-nanosecond Yb:KLu(WO4)2 microchip laser.

    PubMed

    Loiko, P; Serres, J M; Mateos, X; Yumashev, K; Yasukevich, A; Petrov, V; Griebner, U; Aguiló, M; Díaz, F

    2016-06-01

    A diode-pumped Yb:KLu(WO4)2 microchip laser passively Q-switched by a Cr4+:YAG saturable absorber generated a maximum average output power of 590 mW at 1031 nm with a slope efficiency of 55%. The pulse characteristics were 690 ps/47.6 μJ at a pulse repetition frequency of 12.4 kHz. The output beam had an excellent circular profile with M2<1.05. Yb:KLu(WO4)2 is very promising for ultrathin sub-ns microchip lasers.

  10. Integrated microchip-device for the digestion, separation and postcolumn labeling of proteins and peptides.

    PubMed

    Gottschlich, N; Culbertson, C T; McKnight, T E; Jacobson, S C; Ramsey, J M

    2000-08-04

    A microchip device was demonstrated that integrated enzymatic reactions, electrophoretic separation of the reactants from the products and post-separation labeling of proteins and peptides prior to detection. A tryptic digestion of oxidized insulin B-chain was performed in 15 min under stopped flow conditions in a heated channel, and the separation was completed in 1 min. Localized thermal control of the reaction channel was achieved using a resistive heating element. The separated reaction products were then labeled with naphthalene-2,3-dicarboxaldehyde (NDA) and detected by laser-induced fluorescence. A second reaction at elevated temperatures was also demonstrated for the on-chip reduction of disulfide bridges using insulin as a model protein. This device represents one of the highest levels, to date, of monolithic integration of chemical processes on a microchip.

  11. Microdialysis Sampling Coupled to Microchip Electrophoresis with Integrated Amperometric Detection on an All Glass Substrate

    PubMed Central

    Scott, David E.; Grigsby, Ryan; Lunte, Susan M.

    2013-01-01

    The development of an all-glass separation-based sensor using microdialysis coupled to microchip electrophoresis with amperometric detection is described. The system includes a flow-gated interface to inject discrete sample plugs from the microdialysis perfusate into the microchip electrophoresis system. Electrochemical detection was accomplished with a platinum electrode in an in-channel configuration using a wireless electrically isolated potentiostat. To facilitate bonding around the in-channel electrode, a fabrication process was employed that produced a working and a reference electrode flush with the glass surface. Both normal and reversed polarity separations were performed with this sensor. The system was evaluated in vitro for the continuous monitoring of the production of hydrogen peroxide from the reaction of glucose oxidase with glucose. Microdialysis experiments were performed using a BASi loop probe with an overall lag time of approximately five minutes and a rise time of less than 60 seconds. PMID:23794474

  12. Inner structure detection by optical tomography technology based on feedback of microchip Nd:YAG lasers.

    PubMed

    Xu, Chunxin; Zhang, Shulian; Tan, Yidong; Zhao, Shijie

    2013-05-20

    We describe a new optical tomography technology based on feedback of microchip Nd:YAG lasers. In the case of feedback light frequency-shifted, light can be magnified by a fact of 10(6) in the Nd:YAG microchip lasers, which makes it possible to realize optical tomography with a greater depth than current optical tomography. The results of the measuring and imaging of kinds of samples are presented, which demonstrate the feasibility and potential of this approach in the inner structure detection. The system has a lateral resolution of ~1 μm, a vertical resolution of 15 μm and a longitudinal scanning range of over 10mm.

  13. APPLICATIONS OF MICROFLUIDICS AND MICROCHIP ELECTROPHORESIS FOR POTENTIAL CLINICAL BIOMARKER ANALYSIS

    PubMed Central

    Pagaduan, Jayson V.; Sahore, Vishal; Woolley, Adam T.

    2015-01-01

    This article reviews advances over the last 5 years in microfluidics and microchip electrophoresis techniques for detection of clinical biomarkers. The various advantages of miniaturization compared with conventional benchtop methods for detecting biomarkers have resulted in increased interest in developing cheap, fast, and sensitive platforms. We discuss the development of applications of microfluidics and microchip electrophoresis for analysis of various clinical samples for pathogen identification, personalized medicine, and biomarker detection. We highlight the advantages of microfluidics platforms over conventional methods that make them an attractive future diagnostic tool. We also discuss the versatility and adaptability of this technology for analysis of various biomarkers, including lipids, small molecules, carbohydrates, nucleic acids, proteins and cells. Finally, we conclude with a discussion of areas that need to be improved upon to move this technology towards routine clinical and point-of-care applications. PMID:25855148

  14. New dust belts of Uranus: one ring, two ring, red ring, blue ring.

    PubMed

    de Pater, Imke; Hammel, Heidi B; Gibbard, Seran G; Showalter, Mark R

    2006-04-07

    We compared near-infrared observations of the recently discovered outer rings of Uranus with Hubble Space Telescope results. We find that the inner ring, R/2003 U 2, is red, whereas the outer ring, R/2003 U 1, is very blue. Blue is an unusual color for rings; Saturn's enigmatic E ring is the only other known example. By analogy to the E ring, R/2003 U 1 is probably produced by impacts into the embedded moon Mab, which apparently orbits at a location where nongravitational perturbations favor the survival and spreading of submicron-sized dust. R/2003 U 2 more closely resembles Saturn's G ring, which is red, a typical color for dusty rings.

  15. Device-structure dependence of shift in SQUID characteristics by flux trapping

    NASA Astrophysics Data System (ADS)

    Nishino, Toshikazu; Takeda, Eriko; Takagi, Kazumasa

    1994-02-01

    Shifts in voltage-flux characteristics of a SQUID by flux trapping have been measured to study effectiveness of guard ring structure on shielding of magnetic field. The measurements are made under controlled magnetic field. Magnitude of the shift depends on the device structure. It is found that there exists a threshold field for the flux trapping, and the field is reduced by introducing the guard-ring in the SQUID. Comparing to the SQUID without the structure, the SQUID with it needs higher-grade shielding to prevent the flux trapping during cooling down.

  16. Saturn's F-Ring

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This narrow-angle camera image of Saturn's F Ring was taken through the Clear filter while at a distance of 6.9 million km from Saturn on 8 November 1980. The brightness variations of this tightly-constrained ring shown here indicate that the ring is less uniform in makeup than the larger rings. JPL managed the Voyager Project for NASA's Office of Space Science

  17. Encapsulated Electrodes for Microchip Devices: Microarrays and Platinized Electrodes for Signal Enhancement

    PubMed Central

    Selimovic, Asmira; Martin, R. Scott

    2013-01-01

    In this paper, we present two new methodologies of improving the performance of microchip-based electrochemical detection in microfluidic devices. The first part describes the fabrication and characterization of epoxy-embedded gold microelectrode arrays that are evenly spaced and easily modified. Electrodepositions using a gold plating solution can be performed on the electrodes to result in a 3-dimenional pillar array that, when used with microchip-based flow injection analysis, leads to an 8-fold increase in signal (when compared to a single electrode), with the limit of detection (LOD) for catechol being 4 nM. For detecting analytically challenging molecules such as nitric oxide (NO), platinization of electrodes is commonly used to increase the sensitivity. It is shown here that microchip devices containing either the pillar arrays or more traditional glassy carbon electrodes can be modified with platinum black for NO detection. In the case of using glassy carbon electrodes for NO detection, integration of the resulting platinized electrode with microchip-based flow analysis resulted in a 10 times signal increase relative to use of a bare glassy carbon electrode. In addition, it is demonstrated that these electrodes can be coated with Nafion to impart selectivity towards NO over interfering species such as nitrite. The LOD for NO when using the platinum black/Nafion-coated glassy carbon electrode was 9 nM. These electrodes can also be embedded in a polystyrene substrate, with the applicability of these sensitive and selective electrodes being demonstrated by monitoring the ATP-mediated release of NO from endothelial cells immobilized in a microfluidic network without any adhesion factor. PMID:23670668

  18. Effect of gain and loss anisotropy on polarization dynamics in Nd:YAG microchip lasers

    NASA Astrophysics Data System (ADS)

    Zhang, Shaohui; Tan, Yidong; Zhang, Shulian

    2015-04-01

    Relaxation oscillation spectrums of orthogonally polarized modes versus the direction of pump polarization is observed. Unlike previous reports that the anti-phase relaxation peaks are compensated totally, in most cases, they can still be observed in total intensity fluctuation spectrum. An anisotropic rate equation model for orthogonally polarized states Nd:YAG microchip laser is developed to account for the experimental observations. Anisotropic gain and loss are included to explain the polarization dynamics.

  19. Fast analysis of glycosaminoglycans by microchip electrophoresis with in situ fluorescent detection using ethidium bromide.

    PubMed

    Matsuno, Yu-ki; Kinoshita, Mitsuhiro; Kakehi, Kazuaki

    2005-03-09

    We analyzed some glycosaminoglycans and natural and artificial acidic polysaccharides using microchip electrophoresis in the buffer containing ethidium bromide, and found that they were successfully separated and detected within 150 s with comparable sensitivity with that of conventional electrophoresis using cellulose acetate membrane. We applied the technique to the analysis of glycosaminoglycans in pharmaceutical preparations and also in cultured cancer cells. Rapidness and easy operation of the proposed technique are quite useful for routine analysis of glycosaminoglycans.

  20. Encapsulated electrodes for microchip devices: microarrays and platinized electrodes for signal enhancement.

    PubMed

    Selimovic, Asmira; Martin, R Scott

    2013-07-01

    In this paper, we present two new methodologies of improving the performance of microchip-based electrochemical detection in microfluidic devices. The first part describes the fabrication and characterization of epoxy-embedded gold microelectrode arrays that are evenly spaced and easily modified. Electrodepositions using a gold plating solution can be performed on the electrodes to result in a 3D pillar array that, when used with microchip-based flow injection analysis, leads to an eightfold increase in signal (when compared to a single electrode), with the LOD for catechol being 4 nM. For detecting analytically challenging molecules such as nitric oxide (NO), platinization of electrodes is commonly used to increase the sensitivity. It is shown here that microchip devices containing either the pillar arrays or more traditional glassy carbon electrodes can be modified with platinum black (Pt-black) for NO detection. In the case of using glassy carbon electrodes for NO detection, integration of the resulting platinized electrode with microchip-based flow analysis resulted in a ten times signal increase relative to use of a bare glassy carbon electrode. In addition, it is demonstrated that these electrodes can be coated with Nafion to impart selectivity toward NO over interfering species such as nitrite. The LOD for NO when using the Pt-black /Nafion-coated glassy carbon electrode was 9 nM. These electrodes can also be embedded in a polystyrene substrate, with the applicability of these sensitive and selective electrodes being demonstrated by monitoring the adenosine triphosphate-mediated release of NO from endothelial cells immobilized in a microfluidic network without any adhesion factor.

  1. Electrochemical detectors based on carbon and metallic nanostructures in capillary and microchip electrophoresis.

    PubMed

    García-Carmona, Laura; Martín, Aida; Sierra, Tania; González, María Cristina; Escarpa, Alberto

    2017-01-01

    Carbon and metallic-based nanostructures have been progressively implemented as innovative electrochemical detectors in CE and microchip electrophoresis (ME). For both type of nanomaterials and toward selected examples, this review details the impact of these nanomaterials for enhanced detection performance in CE, ME, and paper-based microfluidic devices. The analytical performance and the analytical potential in real world applications is also presented and discussed.

  2. Using an electro-microchip, a nanogold probe, and silver enhancement in an immunoassay.

    PubMed

    Yeh, Chia-Hsien; Huang, Hao-Hsuan; Chang, Tsung-Chain; Lin, Hong-Ping; Lin, Yu-Cheng

    2009-02-15

    This paper presents a novel immunoassay that uses an electro-microchip to detect the immuno-reaction signal, gold nanoparticles (ANPs) as a label of antigen or antibody and as a catalyst for silver precipitation, and the silver enhancement reaction to magnify the detection signal. This study is based on the direct immunoassay (two-layer format) and the sandwich immunoassay (three-layer format). The ANPs were introduced into the electro-microchip by the specific binding of the antibodies-ANPs conjugates and then were coupled with silver enhancement to produce black spots of silver metal. The silver precipitation constructs a "bridge" between two electrodes of the electro-microchip allowing electrons to pass. The variation of impedance can be easily measured with a commercial LCR meter. Various gap sizes (20, 50, 100, and 200 microm) of the electrodes of electro-microchips were designed for the sensitivity study. The experimental data show that a chip with a 20microm gap has the highest sensitivity. There was a significant difference in impedance between the experiment sample and the negative control after 10 min of reaction time. The proposed method requires less time and fewer steps than the conventional enzyme-linked immunosorbent assay (ELISA). In addition, it shows a high detection sensitivity (10 microg/mL of 1st antibody (IgG) immobilized on slides and 1 ng/mL of antigen (protein A)). There is a clear distinction between the signal intensity and the logarithm of the sample concentration. The proposed new immunoassay method has potential applications in proteomics research and clinical diagnosis.

  3. Low viscous separation media for genomics and proteomics analysis on microchip electrophoresis system.

    PubMed

    Jabasini, Mohammad; Murakami, Yuji; Kaji, Noritada; Tokeshi, Manabu; Baba, Yoshinobu

    2006-04-01

    Microchip electrophoresis has widely grown during the past few years, and it has showed a significant result as a strong separation tool for genomic as well as proteomic researches. To enhance and expand the role of microchip electrophoresis, several studies have been proposed especially for the low viscous separation media, which is an important factor for the success of microchip with its narrow separation channels. In this paper we show an overview for the done researches in the field of low viscous media developed for the use in microchip electrophoresis. For genomic separation studies polyhydroxy additives have been used enhance the separation of DNA at low polymer concentration of HPMC (Hydroxypropylmethyl cellulose) which could keep the viscosity low. Mixtures of poly(ethylene oxide) as well as Hydroxyporpyl cellulose have been successfully introduced for chip separation. Furthermore high molecular mass polyacrylamides at low concentrations have been studied for DNA separation. A mixture of polymer nanoparticle with conventional polymers could show a better resolution for DNA at low concentration of the polymer. For the proteomic field isoelectric focusing on chip has been well overviewed since it is the most viscous separation media which is well used for the protein separation. The different types of isoelectric focusing such as the ampholyte-free type, the thermal type as well as the ampholyte-depended type have been introduced in this paper. Isoelectric focusing on chip with its combination with sodium dodecyl sulfate (SDS) page or free solution could give a better separation. Several application for this low viscous separation medias for either genomic or proteomic could clearly show the importance of this field.

  4. Trapping and Probing Antihydrogen

    SciTech Connect

    Wurtele, Jonathan

    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. Versatile electrostatic trap

    SciTech Connect

    Veldhoven, Jacqueline van; Bethlem, Hendrick L.; Schnell, Melanie; Meijer, Gerard

    2006-06-15

    A four electrode electrostatic trap geometry is demonstrated that can be used to combine a dipole, quadrupole, and hexapole field. A cold packet of {sup 15}ND{sub 3} molecules is confined in both a purely quadrupolar and hexapolar trapping field and additionally, a dipole field is added to a hexapole field to create either a double-well or a donut-shaped trapping field. The profile of the {sup 15}ND{sub 3} packet in each of these four trapping potentials is measured, and the dependence of the well-separation and barrier height of the double-well and donut potential on the hexapole and dipole term are discussed.

  6. Steam trap monitor

    DOEpatents

    Ryan, M.J.

    1987-05-04

    A steam trap monitor positioned downstream of a steam trap in a closed steam system includes a first sensor (a hot finger) for measuring the energy of condensate and a second sensor (a cold finger) for measuring the total energy of condensate and steam in the line. The hot finger includes one or more thermocouples for detecting condensate level and energy, while the cold finger contains a liquid with a lower boiling temperature than that of water. Vapor pressure from the liquid is used to do work such as displacing a piston or bellow in providing an indication of total energy (steam + condensate) of the system. Processing means coupled to and responsive to outputs from the hot and cold fingers subtracts the former from the latter to provide an indication of the presence of steam downstream from the trap indicating that the steam trap is malfunctioning. 2 figs.

  7. On certain Hecke rings

    PubMed Central

    Evens, Sam; Bressler, Paul

    1987-01-01

    We examine rings that embed into the smash product of the group algebra of the Weyl group with the field of meromorphic functions on the Cartan subalgebra and are generated by elements that satisfy braid relations. We prove that every such ring is isomorphic to either the Hecke algebra, the nil Hecke ring, or the group algebra of the Weyl group. PMID:16593804

  8. The Jumping Ring Experiment

    ERIC Educational Resources Information Center

    Baylie, M.; Ford, P. J.; Mathlin, G. P.; Palmer, C.

    2009-01-01

    The jumping ring experiment has become central to liquid nitrogen shows given as part of the outreach and open day activities carried out within the University of Bath. The basic principles of the experiment are described as well as the effect of changing the geometry of the rings and their metallurgical state. In general, aluminium rings are…

  9. Rings Around Uranus

    ERIC Educational Resources Information Center

    Maran, Stephen P.

    1977-01-01

    Events leading up to the discovery of the rings of Uranus are described. The methods used and the logic behind the methods are explained. Data collected to prove the existence of the rings are outlined and theories concerning the presence of planetary rings are presented. (AJ)

  10. Soft normed rings.

    PubMed

    Uluçay, Vakkas; Şahin, Mehmet; Olgun, Necati

    2016-01-01

    Molodtsov introduced the concept of soft sets, which can be seen as a new mathematical tool for dealing with uncertainty. In this paper, we initiate the study of soft normed rings by soft set theory. The notions of soft normed rings, soft normed ideals, soft complete normed rings are introduced and also several related properties and examples are given.

  11. Ultracold Gas of Excitons in Traps

    DTIC Science & Technology

    2012-06-08

    Excitons in a GaAs Quantum-Well Structurewith a Diamond-Shaped Electrostatic Trap, Physical Review Letters, (08 2009): 87403. doi: 2012/06/08 14:38:06 19...Kinetics of the inner ring in the exciton emission pattern in coupled GaAs quantum wells, Physical Review B, (10 2009): 155331. doi: 2012/06/08 14:28:30...17 Sen Yang, , L. V. Butov, , L. S. Levitov, , B. D. Simons,, A. C. Gossard. Exciton front propagation in photoexcited GaAs quantum wells, Physical

  12. Electrophoretic Separation-Mass Spectrometric Detection on Polymer Microchip Directly Integrated with a Nanospray Tip

    NASA Astrophysics Data System (ADS)

    Kitagawa, Fumihiko; Shinohara, Hidetoshi; Mizuno, Jun; Otsuka, Koji; Shoji, Shuichi

    We fabricated a polymer chip for microchip electrophoresis-mass spectrometry (MCE—MS). As a substrate material, cycloolefin polymer (COP) was selected due to its high chemical durability and easy metallization for the electrode. A COP microchip with a conventional cross-type channel configuration for the MCE separation was fabricated by hot embossing. After bonding with a rid substrate, a nano electrospray ionization (nano-ESI) tip structure for MS detection was machined directly at the opening of the separation channel end. A gold electrode to keep the electric contact for ESI was deposited around the nanospray tip by electron beam evaporation. When the voltage of 3.0 and 2.0 kV was applied to the inlet and the ESI electrode, respectively, the formation of Taylor cone and stable electrospray were observed at the channel opening. In infusion analysis of caffeine, the MS spectrum with parent mass number of 195, which accords with that of the protonated caffeine, was successfully obtained in the positive mode. Furthermore, the MCE separation and ESI-MS detection of caffeine and arginine was also successfully achieved with resolution of 1.0. Therefore, these results demonstrated that the fabricated microchip integrated with the nano-ESI tip can be employed as the MCE—ESI-MS device.

  13. DNA sequencing by hybridization to microchip octa-and decanucleotides extended by stacked pentanucleotides.

    PubMed Central

    Parinov, S; Barsky, V; Yershov, G; Kirillov, E; Timofeev, E; Belgovskiy, A; Mirzabekov, A

    1996-01-01

    The efficiency of sequencing by hybridization to an oligonucleotide microchip grows with an increase in the number and in the length of the oligonucleotides; however, such increases raise enormously the complexity of the microchip and decrease the accuracy of hybridization. We have been developing the technique of contiguous stacking hybridization (CSH) to circumvent these shortcomings. Stacking interactions between adjacent bases of two oligonucleotides stabilize their contiguous duplex with DNA. The use of such stacking increases the effective length of microchip oligonucleotides, enhances sequencing accuracy and allows the sequencing of longer DNA. The effects of mismatches, base composition, length and other factors on the stacking are evaluated. Contiguous stacking hybridization of DNA with immobilized 8mers and one or two 5mers labeled with two different fluorescent dyes increases the effective length of sequencing oligonucleotides from 8 to 13 and 18 bases, respectively. The incorporation of all four bases or 5-nitroindole as a universal base into different positions of the 5mers permitted a decrease in the number of additional rounds of hybridization. Contiguous stacking hybridization appears to be a promising approach to significantly increasing the efficiency of sequencing by hybridization. PMID:8760885

  14. A new soft lithographic route for the facile fabrication of hydrophilic sandwich microchips.

    PubMed

    Li, Li; Bi, Xiaodong; Yu, Jianzhao; Ren, Carolyn L; Liu, Zhen

    2012-08-01

    Manufacturing materials are an essential element for the fabrication of microfluidic chips. PDMS, the most widely used polymeric material, is associated with apparent disadvantages such as hydrophobic nature, while other materials also suffer from some limitations. In this paper, a new soft lithographic route was proposed for the facile manufacturing of hydrophilic sandwich microchips, using bisphenol A based epoxy acrylate (BABEA) as a new patterning material. The BABEA copolymers are hydrophilic, highly transparent in visible range while highly untransparent when the wavelength is less than 290 nm, and of high replication fidelity. By combining with appropriate monomers, including glycidyl methacrylate, methylmethacrylate, and acrylic acid, the copolymers contain active functional groups, which allows for easy postmodification for desirable functional units. A fabrication procedure was proposed for manufacturing hybrid quartz/BABEA copolymer/quartz microchips. In the procedure, no micromachining equipments, wet etching, or imprinting techniques were involved, making the fabrication approach applicable in ordinary chemistry laboratories. The performance of the prepared microchips was demonstrated in terms of CIEF with UV-whole channel imaging detection. The hydrophilic microchannel ensures stable focusing while the polymeric middle layer acts as a perfectly aligned optical slit for whole channel UV absorbance detection.

  15. Low-cost fabrication of poly(methyl methacrylate) microchips using disposable gelatin gel templates.

    PubMed

    Chen, Zhi; Yu, Zhengyin; Chen, Gang

    2010-06-15

    A simple method based on disposable gelatin gel templates has been developed for the low-cost fabrication of poly(methyl methacrylate) (PMMA) microfluidic chips. Gelatin was dissolved in glycerol aqueous solution under heat to prepare a thermally reversible impression material. The molten gel was then sandwiched between a glass plate and a SU-8 template bearing negative relief of microstructure. After cooling, the negative SU-8 template could be easily separated from the solidified gelatin gel and a layer of gelatin template bearing positive relief of the microstructure was left on the glass plate. Subsequently, prepolymerized methyl methacrylate molding solution containing a UV-initiator was sandwiched between the gel template and a PMMA plate and was allowed to polymerize under UV light to fabricate PMMA channel plate at room temperature. Complete microchips could be obtained by bonding the channel plates with covers using plasticizer-assisted thermal bonding at 90 degrees C. Gelatin gel template can be mass-produced and will find application in the mass production of PMMA microchips at low cost. The prepared microfluidic microchips have been successfully employed in the capillary electrophoresis analysis of several ions in connection with contactless conductivity detection.

  16. Improving chip-to-chip precision in disposable microchip capillary electrophoresis devices with internal standards.

    PubMed

    Bidulock, Allison C E; van den Berg, Albert; Eijkel, Jan C T

    2015-03-01

    To realize portable systems for routine measurements in point-of-care settings, MCE methods are required to be robust across many single-use chips. While it is well-known internal standards (ISTDs) improve run-to-run precision, a systematic investigation is necessary to determine the significance of chip-to-chip imprecision in MCE and how ISTDs account for it. This paper addresses this question by exploring the reproducibility of Na quantification across six basic, in-house fabricated microchips. A dataset of 900 electrophoerograms was collected from analyzing five concentrations of NaCl with two ISTDs (CsCl and LiCl). While both improved the peak area reproducibility, the Na/Cs ratio was superior to the Na/Li ratio (improving the RSD by a factor of 2-4, depending on the Na concentration). We attribute this to the significant variation in microchannel surface properties, which was accounted for by cesium but not lithium. Microchip dimension and detector variations were only a few percent, and could be improved through commercial fabrication over in-house made microchips. These results demonstrate that ISTDs not only correct for intrachip imprecision, but are also a viable means to correct for chip-to-chip imprecision inherent in disposable, point-of-care MCE devices. However, as expected, the internal standard must be carefully chosen.

  17. Microchip-based cellular biochemical systems for practical applications and fundamental research: from microfluidics to nanofluidics.

    PubMed

    Xu, Yan; Jang, Kihoon; Yamashita, Tadahiro; Tanaka, Yo; Mawatari, Kazuma; Kitamori, Takehiko

    2012-01-01

    By combining cell technology and microchip technology, innovative cellular biochemical tools can be created from the microscale to the nanoscale for both practical applications and fundamental research. On the microscale level, novel practical applications taking advantage of the unique capabilities of microfluidics have been accelerated in clinical diagnosis, food safety, environmental monitoring, and drug discovery. On the other hand, one important trend of this field is further downscaling of feature size to the 10(1)-10(3) nm scale, which we call extended-nano space. Extended-nano space technology is leading to the creation of innovative nanofluidic cellular and biochemical tools for analysis of single cells at the single-molecule level. As a pioneering group in this field, we focus not only on the development of practical applications of cellular microchip devices but also on fundamental research to initiate new possibilities in the field. In this paper, we review our recent progress on tissue reconstruction, routine cell-based assays on microchip systems, and preliminary fundamental method for single-cell analysis at the single-molecule level with integration of the burgeoning technologies of extended-nano space.

  18. Characterization and performance of injection molded poly(methylmethacrylate) microchips for capillary electrophoresis.

    PubMed

    Nikcevic, Irena; Lee, Se Hwan; Piruska, Aigars; Ahn, Chong H; Ridgway, Thomas H; Limbach, Patrick A; Wehmeyer, K R; Heineman, William R; Seliskar, Carl J

    2007-06-22

    Injection molded poly(methylmethacrylate) (IM-PMMA), chips were evaluated as potential candidates for capillary electrophoresis disposable chip applications. Mass production and usage of plastic microchips depends on chip-to-chip reproducibility and on analysis accuracy. Several important properties of IM-PMMA chips were considered: fabrication quality evaluated by environmental scanning electron microscope imaging, surface quality measurements, selected thermal/electrical properties as indicated by measurement of the current versus applied voltage (I-V) characteristic and the influence of channel surface treatments. Electroosmotic flow was also evaluated for untreated and O2 reactive ion etching (RIE) treated surface microchips. The performance characteristics of single lane plastic microchip capillary electrophoresis (MCE) separations were evaluated using a mixture of two dyes-fluorescein (FL) and fluorescein isothiocyanate (FITC). To overcome non-wettability of the native IM-PMMA surface, a modifier, polyethylene oxide was added to the buffer as a dynamic coating. Chip performance reproducibility was studied for chips with and without surface modification via the process of RIE with O2 and by varying the hole position for the reservoir in the cover plate or on the pattern side of the chip. Additionally, the importance of reconditioning steps to achieve optimal performance reproducibility was also examined. It was found that more reproducible quantitative results were obtained when normalized values of migration time, peak area and peak height of FL and FITC were used instead of actual measured parameters.

  19. Prototyping disposable electrophoresis microchips with electrochemical detection using rapid marker masking and laminar flow etching.

    PubMed

    Manica, Drew P; Ewing, Andrew G

    2002-11-01

    Two novel methods are described for the fabrication of components for microchip capillary electrophoresis with electrochemical detection (microchip CEEC) on glass substrates. First, rapid marker masking is introduced as a completely nonphotolithographic method of patterning and fabricating integrated thin-film metal electrodes onto a glass substrate. The process involves applying the pattern directly onto the metal layer with a permanent marker that masks the ensuing chemical etch. The method is characterized, and the performance of the resulting electrode is evaluated using catecholamines. The response compares well with photolithographically defined electrodes and exhibits detection limits of 648 nM and 1.02 microM for dopamine and catechol, respectively. Second, laminar flow etching is introduced as a partially nonphotolithographic method of replicating channel networks onto glass substrates. The replication process involves applying a poly(dimethylsiloxane) (PDMS) mold of the channel network onto a slide coated with a sacrificial metal layer and then pulling solutions of metal etchants through the channels to transfer the pattern onto the sacrificial layer. The method is tested, and prototype channel networks are shown. These methods serve to overcome the time and cost involved in fabricating glass-based microchips, thereby making the goal of a disposable high performance lab-on-a-chip more attainable.

  20. Induction of trap formation in nematode-trapping fungi by bacteria-released ammonia.

    PubMed

    Su, H N; Xu, Y Y; Wang, X; Zhang, K Q; Li, G H

    2016-04-01

    A total of 11 bacterial strains were assayed for bacteria-induced trap formation in the nematode-trapping fungus Arthrobotrys oligospora YMF1·01883 with two-compartmented Petri dish. These strains were identified on the basis of their 16S rRNA gene sequences. Volatile organic compounds (VOCs) of eight isolates were extracted using solid-phase micro-extraction (SPME) and their structures were identified based on gas chromatography-mass spectrometry (GC-MS). At the same time, all isolates were used for quantitative measurement of ammonia by the indophenol blue method. The effects of pure commercial compounds on inducement of trap formation in A. oligospora were tested. Taken together, results demonstrated that the predominant bacterial volatile compound inducing trap formation was ammonia. Meanwhile, ammonia also played a role in other nematode-trapping fungi, including Arthrobotrys guizhouensis YMF1·00014, producing adhesive nets; Dactylellina phymatopaga YMF1·01474, producing adhesive knobs; Dactylellina cionopaga YMF1·01472, producing adhesive columns and Drechslerella brochopaga YMF1·01829, producing constricting rings.

  1. Optical trapping of nanoshells

    NASA Astrophysics Data System (ADS)

    Hester, Brooke C.; Crawford, Alice; Kishore, Rani B.; Helmerson, Kristian; Halas, Naomi J.; Levin, Carly

    2007-09-01

    We investigate near-resonant trapping of Rayleigh particles in optical tweezers. Although optical forces due to a near-resonant laser beam have been extensively studied for atoms, the situation for larger particles is that the laser wavelength is far from any absorption resonance. Theory predicts, however, that the trapping force exerted on a Rayleigh particle is enhanced, and may be three to fifty times larger for frequencies near resonance than for frequencies far off resonance. The ability to selectively trap only particles with a given absorption peak may have many practical applications. In order to investigate near-resonant trapping we are using nanoshells, particles with a dielectric core and metallic coating that can exhibit plasmon resonances. The resonances of the nanoshells can be tuned by adjusting the ratio of the radius of the dielectric core, r I, to the overall radius, r II, which includes the thickness of the metallic coating. Our nanoshells, fabricated at Rice University, consist of a silica core with a gold coating. Using back focal plane detection, we measure the trap stiffness of a single focus optical trap (optical tweezers), from a diode laser at 853 nm for nanoshells with several different r I/r II ratios.

  2. Microfabricated cylindrical ion trap

    DOEpatents

    Blain, Matthew G.

    2005-03-22

    A microscale cylindrical ion trap, having an inner radius of order one micron, can be fabricated using surface micromachining techniques and materials known to the integrated circuits manufacturing and microelectromechanical systems industries. Micromachining methods enable batch fabrication, reduced manufacturing costs, dimensional and positional precision, and monolithic integration of massive arrays of ion traps with microscale ion generation and detection devices. Massive arraying enables the microscale cylindrical ion trap to retain the resolution, sensitivity, and mass range advantages necessary for high chemical selectivity. The microscale CIT has a reduced ion mean free path, allowing operation at higher pressures with less expensive and less bulky vacuum pumping system, and with lower battery power than conventional- and miniature-sized ion traps. The reduced electrode voltage enables integration of the microscale cylindrical ion trap with on-chip integrated circuit-based rf operation and detection electronics (i.e., cell phone electronics). Therefore, the full performance advantages of microscale cylindrical ion traps can be realized in truly field portable, handheld microanalysis systems.

  3. Causes of ring-related leg injuries in birds - evidence and recommendations from four field studies.

    PubMed

    Griesser, Michael; Schneider, Nicole A; Collis, Mary-Anne; Overs, Anthony; Guppy, Michael; Guppy, Sarah; Takeuchi, Naoko; Collins, Pete; Peters, Anne; Hall, Michelle L

    2012-01-01

    One of the main techniques for recognizing individuals in avian field research is marking birds with plastic and metal leg rings. However, in some species individuals may react negatively to rings, causing leg injuries and, in extreme cases, the loss of a foot or limb. Here, we report problems that arise from ringing and illustrate solutions based on field data from Brown Thornbills (Acanthiza pusilla) (2 populations), Siberian Jays (Perisoreus infaustus) and Purple-crowned Fairy-wrens (Malurus coronatus). We encountered three problems caused by plastic rings: inflammations triggered by material accumulating under the ring (Purple-crowned Fairy-wrens), contact inflammations as a consequence of plastic rings touching the foot or tibio-tarsal joint (Brown Thornbills), and toes or the foot getting trapped in partly unwrapped flat-band colour rings (Siberian Jays). Metal rings caused two problems: the edges of aluminium rings bent inwards if mounted on top of each other (Brown Thornbills), and too small a ring size led to inflammation (Purple-crowned Fairy-wrens). We overcame these problems by changing the ringing technique (using different ring types or larger rings), or using different adhesive. Additionally, we developed and tested a novel, simple technique of gluing plastic rings onto metal rings in Brown Thornbills. A review of studies reporting ring injuries (N = 23) showed that small birds (<55 g body weight) are more prone to leg infections while larger birds (>35 g) tend to get rings stuck over their feet. We give methodological advice on how these problems can be avoided, and suggest a ringing hazard index to compare the impact of ringing in terms of injury on different bird species. Finally, to facilitate improvements in ringing techniques, we encourage online deposition of information regarding ringing injuries of birds at a website hosted by the European Union for Bird Ringing (EURING).

  4. The use of ethylene glycol solution as the running buffer for highly efficient microchip-based electrophoresis in unmodified cyclic olefin copolymer microchips.

    PubMed

    Wang, Qin; Zhang, Yuan; Ding, Hui; Wu, Jing; Wang, Lili; Zhou, Lei; Pu, Qiaosheng

    2011-12-30

    An ethylene glycol solution was used as the electrophoretic running buffer in unmodified cyclic olefin copolymer (COC) microchips to minimize the interactions between the analytes and the hydrophobic walls of the plastic microchannels, enhance the resolution of the analytes and eliminate the uncontrollable dispersion caused by uneven liquid levels and non-uniform surfaces of the separation channels. Five amino acids that were labeled with fluorescein isothiocyanate (FITC) were used as model analytes to examine the separation efficiency. The effects of ethylene glycol concentration, pH and sodium tetraborate concentration were systematically investigated. The five FITC-labeled amino acids were effectively resolved using a COC microchip with an effective length of 2.5 cm under optimum conditions, which included using a running buffer of 20 mmol/L sodium tetraborate in ethylene glycol:water (80:20, v/v), pH 6.7. A theoretical plate number of 4.8 × 10(5)/m was obtained for aspartic acid. The system exhibited good repeatability, and the relative standard deviations (n=5) of the peak areas and migration times were no more than 3.4% and 0.7%, respectively. Furthermore, the system was successfully applied to elucidate these five amino acids in human saliva.

  5. Microchip electrophoresis with background electrolyte containing polyacrylic acid and high content organic solvent in cyclic olefin copolymer microchips for easily adsorbed dyes.

    PubMed

    Wei, Xuan; Sun, Ping; Yang, Shenghong; Zhao, Lei; Wu, Jing; Li, Fengyun; Pu, Qiaosheng

    2016-07-29

    Plastic microchips can significantly reduce the fabrication cost but the adsorption of some analytes limits their application. In this work, background electrolyte containing ionic polymer and high content of organic solvent was adopted to eliminate the analyte adsorption and achieve highly efficient separation in microchip electrophoresis. Two dyes, rhodamine 6G (Rh6G) and rhodamine B (RhB) were used as the model analytes. By using methanol as the organic solvent and polyacrylic acid (PAA) as a multifunctional additive, successful separation of the two dyes within 75μm id. microchannels was realized. The role of PAA is multiple, including viscosity regulator, selectivity modifier and active additive for counteracting analyte adsorption on the microchannel surface. The number of theoretical plate of 7.0×10(5)/m was attained within an effective separation distance of 2cm using background electrolyte consisting 80% methanol, 0.36% PAA and 30mmol/L phosphate at pH 5.0. Under optimized conditions, relative standard deviations of Rh6G and RhB detection (n=5) were no more than 1.5% for migration time and 2.0% for peak area, respectively. The limit of detection (S/N=3) was 0.1nmol/L for Rh6G. The proposed technique was applied in the determination of both Rh6G and RhB in chilli powder and lipstick samples with satisfactory recoveries of 81.3-103.7%.

  6. Static Trapping of Polar Molecules in a Traveling Wave Decelerator

    NASA Astrophysics Data System (ADS)

    Quintero-Pérez, Marina; Jansen, Paul; Wall, Thomas E.; van den Berg, Joost E.; Hoekstra, Steven; Bethlem, Hendrick L.

    2013-03-01

    We present experiments on decelerating and trapping ammonia molecules using a combination of a Stark decelerator and a traveling wave decelerator. In the traveling wave decelerator, a moving potential is created by a series of ring-shaped electrodes to which oscillating high voltages (HV) are applied. By lowering the frequency of the applied voltages, the molecules confined in the moving trap are decelerated and brought to a standstill. As the molecules are confined in a true 3D well, this kind of deceleration has practically no losses, resulting in a great improvement on the usual Stark deceleration techniques. The necessary voltages are generated by amplifying the output of an arbitrary wave generator using fast HV amplifiers, giving us great control over the trapped molecules. We illustrate this by experiments in which we adiabatically cool trapped NH3 and ND3 molecules and resonantly excite their motion.

  7. Electron Cloud Trapping in Recycler Combined Function Dipole Magnets

    SciTech Connect

    Antipov, Sergey A.; Nagaitsev, S.

    2016-10-04

    Electron cloud can lead to a fast instability in intense proton and positron beams in circular accelerators. In the Fermilab Recycler the electron cloud is confined within its combined function magnets. We show that the field of combined function magnets traps the electron cloud, present the results of analytical estimates of trapping, and compare them to numerical simulations of electron cloud formation. The electron cloud is located at the beam center and up to 1% of the particles can be trapped by the magnetic field. Since the process of electron cloud build-up is exponential, once trapped this amount of electrons significantly increases the density of the cloud on the next revolution. In a Recycler combined function dipole this multiturn accumulation allows the electron cloud reaching final intensities orders of magnitude greater than in a pure dipole. The multi-turn build-up can be stopped by injection of a clearing bunch of 1010 p at any position in the ring.

  8. Fundamental studies of ion injection and trapping of electrosprayed ions on a quadrupole ion trap mass spectrometer

    NASA Astrophysics Data System (ADS)

    Quarmby, Scott Thomas

    The quadrupole ion trap is a highly versatile and sensitive analytical mass spectrometer. Because of the advantages offered by the ion trap, there has been intense interest in coupling it to ionization techniques such as electrospray which form ions externally to the ion trap. In this work, experiments and computer simulations were employed to study the injection of electrosprayed ions into the ion trap of a Finnigan MAT LCQ LC/MS n mass spectrometer. The kinetic energy distribution of the ion beam was characterized and found to be relatively wide, a result of the high pressures from the atmospheric pressure source. One of the most important experimental parameters which affects ion injection efficiency is the RF voltage applied to the ring electrode. A theoretical model was fit to experimental data allowing the optimum RF voltage for trapping a given m/z ion to be predicted. Computer simulations of ion motion were performed to study the effect of various instrumental parameters on trapping efficiency. A commercially available ion optics program, SIMION v6.0, was chosen because it allowed the actual ion trap electrode geometry including endcap holes to be simulated. In contrast to previous computer simulations, SIMION provided the ability to start ions outside the ion trap and to simulate more accurately the injection of externally formed ions. The endcap holes were found to allow the RF field to penetrate out of the ion trap and affect ions as they approached the ion trap. From these simulations, a model for the process by which injected ions are trapped was developed. Using these computer simulations, techniques of improving trapping efficiency were investigated. Most previous techniques perturb ions which are already in the ion trap and therefore cannot be used to accumulate ions; the ability to accumulate ions is a necessity with ionization sources such as electrospray which form ions continuously. One such novel technique for improving trapping efficiency

  9. Saturn's largest ring.

    PubMed

    Verbiscer, Anne J; Skrutskie, Michael F; Hamilton, Douglas P

    2009-10-22

    Most planetary rings in the Solar System lie within a few radii of their host body, because at these distances gravitational accelerations inhibit satellite formation. The best known exceptions are Jupiter's gossamer rings and Saturn's E ring, broad sheets of dust that extend outward until they fade from view at five to ten planetary radii. Source satellites continuously supply the dust, which is subsequently lost in collisions or by radial transport. Here we report that Saturn has an enormous ring associated with its outer moon Phoebe, extending from at least 128R(S) to 207R(S) (Saturn's radius R(S) is 60,330 km). The ring's vertical thickness of 40R(S) matches the range of vertical motion of Phoebe along its orbit. Dynamical considerations argue that these ring particles span the Saturnian system from the main rings to the edges of interplanetary space. The ring's normal optical depth of approximately 2 x 10(-8) is comparable to that of Jupiter's faintest gossamer ring, although its particle number density is several hundred times smaller. Repeated impacts on Phoebe, from both interplanetary and circumplanetary particle populations, probably keep the ring populated with material. Ring particles smaller than centimetres in size slowly migrate inward and many of them ultimately strike the dark leading face of Iapetus.

  10. On the solar dust ring(s)

    NASA Astrophysics Data System (ADS)

    Mukai, T.

    Based on a mechanism to form the solar dust ring, it is proved that the observed peak in infrared F-corona cannot be explained by silicate type grains alone. Preliminary analysis on the recent infrared data of the F-corona by Maihara et al. (1984) has suggested that the ring particles have different physical properties compared with the dust grains, which produce the background F-corona.

  11. Transport currents measured in ring samples: test of superconducting weld

    NASA Astrophysics Data System (ADS)

    Zheng, H.; Claus, H.; Chen, L.; Paulikas, A. P.; Veal, B. W.; Olsson, B.; Koshelev, A.; Hull, J.; Crabtree, G. W.

    2001-02-01

    The critical current densities in bulk melt-textured YBa 2Cu 3O x and across superconducting “weld” joints are measured using scanning Hall probe measurements of the trapped magnetic field in ring samples. With this method, critical current densities are obtained without the use of electrical contacts. Large persistent currents are induced in ring samples at 77 K, after cooling in a 3 kG field. These currents can be determined from the magnetic field they produce. At 77 K a supercurrent exceeding 2000 A (about 10 4 A/cm 2) was induced in a 2 cm diameter ring; this current produces a magnetic field exceeding 1.5 kG in the bore of the ring. We demonstrate that when a ring is cut, and the cut is repaired by a superconducting weld, the weld joint can transmit the same high supercurrent as the bulk.

  12. Online determination of copper in aluminum alloy by microchip solvent extraction using isotope dilution ICP-MS method.

    PubMed

    Kagawa, Tsuyoshi; Ohno, Masashi; Seki, Tatsuya; Chikama, Katsumi

    2009-09-15

    Isotope dilution mass spectroscopy (IDMS)/ICP-MS combined with microchip solvent extraction was successfully applied for the online determination of copper in an aluminum alloy. The microchip solvent extraction was developed for the separation of Cu from major element, and optimal pH range was wider than that of the batchwise extraction method. The dimensions of the microchip were 30 mm x 70 mm and that of micro-channel on the microchip was 180 microm wide and 40 microm deep. The copper complex with 8-hydroxyquinoline was extracted into o-xylene at pH 5.5 and back extracted with 0.1 mol l(-1) nitric acid at flow rate of 20 microl min(-1). The total extraction efficiency (water/organic solvent/nitric acid) was around 40%. IDMS/ICP-MS was coupled with solvent extraction for precise determination of Cu. The extraction and back-extraction on the microchip took about 1s and the total measurement time for the IDMS/ICP-MS was about 40s/sample. The blank value of this method was 0.1 ng g(-1). The proposed method was used for the determination of Cu in Al standard materials (JSAC 0121-C, The Japan Society for Analytical Chemistry and 7074 Al alloy, Nippon Light Metal Co. Ltd.). The obtained analytical results are in good agreement with the certified values.

  13. Poly(dimethylsiloxane) microchip-based immunoassay with multiple reaction zones: Toward on-chip multiplex detection platform

    SciTech Connect

    Shao, Guocheng; Wang, Jun; Li, Zhaohui; Saraf, Laxmikant V.; Wang, Wanjun; Lin, Yuehe

    2011-09-20

    In this work, a poly(dimethylsiloxane) (PDMS) microchip-based immuno-sensing platform with integrated pneumatic micro valves is described. The microchip was fabricated with multiple layer soft lithography technology. By controlling the activation status of corresponding valves, reagent flows in the microchannel network can be well manipulated so that immuno-reactions only take place at designated reaction zones (DRZs). Four DRZs are included in the prototype microchip. Since these DRZs are all isolated from each other by micro valves, cross contamination is prevented. Using the inner surface of the all-PDMS microchannel as immunoassay substrate, on-chip sandwich format solid phase immunoassay was performed to demonstrate the feasibility of this immuno-sensing platform. Mouse IgG and fluorescein isothiocyanate (FITC) were used as the model analyte and the signal reporter respectively. Only 10 ul sample is needed for the assay and low detection limit of 5 ng/ml (≈33 pM) was achieved though low-cost polyclonal antibodies were used in our experiment for feasibility study only. The encouraging results from mouse IgG immunoassay proved the feasibility of our microchip design. With slight modification of the assay protocol, the same chip design can be used for multi-target detection and can provide a simple, cost-effective and integrated microchip solution for multiplex immunoassay applications.

  14. Carbon fiber nanoelectrodes applied to microchip electrophoresis amperometric detection of neurotransmitter dopamine in rat pheochromocytoma (PC12) cells.

    PubMed

    Cheng, Han; Huang, Wei-Hua; Chen, Rong-Sheng; Wang, Zong-Li; Cheng, Jie-Ke

    2007-05-01

    Microelectrodes have been adopted in electrochemical detection for CE or microchip CE in recent years. In this paper, the use of nanoelectrodes (with tip diameter of 100-300 nm) as the electrochemical detector in microchip CE is firstly reported. The experimental results indicated that both the sensitivity and resolution of microchip CE with the carbon fiber nanoelectrode (CFNE) amperometric detection have been improved markedly comparing with the traditional microelectrodes. The detection limit of dopamine (S/N = 3) is 5.9x10(-8) M, which is one or two orders of magnitude lower than that reported so far, and the resolution of dopamine (DA) and isoprenaline (IP) has also improved from 0.6 (using 7 mum carbon fiber microelectrodes, CFME) to 1.0. We assembled a novel and easily operated microchip CE system with end-column amperometric detection, which allows the convenient and fast replacement of the passivated electrodes. Under the optimized condition, the RSDs of peak height and migration time are 1.47 and 0.31%, respectively (n = 40), indicating that the system displays excellent reproducibility. The nanoelectrode-based microchip CE system has been successfully applied to the determination of DA in cultured rat pheochromocytoma (PC12) cells, and the average content of DA in an individual PC12 cell is 0.54 +/- 0.07 fmol, which is in good agreement with that reported in the literature.

  15. Switching Oxide Traps

    NASA Technical Reports Server (NTRS)

    Oldham, Timothy R.

    2003-01-01

    We consider radiation-induced charge trapping in SiO2 dielectric layers, primarily from the point of view of CMOS devices. However, SiO2 insulators are used in many other ways, and the same defects occur in other contexts. The key studies, which determined the nature of the oxide charge traps, were done primarily on gate oxides in CMOS devices, because that was the main radiation problem in CMOS at one time. There are two major reviews of radiation-induced oxide charge trapping already in the literature, which discuss the subject in far greater detail than is possible here. The first of these was by McLean et al. in 1989, and the second, ten years later, was intended as an update, because of additional, new work that had been reported. Basically, the picture that has emerged is that ionizing radiation creates electron-hole pairs in the oxide, and the electrons have much higher mobility than the holes. Therefore, the electrons are swept out of the oxide very rapidly by any field that is present, leaving behind any holes that escape the initial recombination process. These holes then undergo a polaron hopping transport toward the Si/SiO2 interface (under positive bias). Near the interface, some fraction of them fall into deep, relatively stable, long-lived hole traps. The nature and annealing behavior of these hole traps is the main focus of this paper.

  16. Dust and Planetary Rings

    NASA Astrophysics Data System (ADS)

    Siddiqui, Muddassir

    ABSTRACT Space is not empty it has comic radiations (CMBR), dust etc. Cosmic dust is that type of dust which is composed of particles in space which vary from few molecules to 0.1micro metres in size. This type of dust is made up of heavier atoms born in the heart of stars and supernova. Mainly it contains dust grains and when these dust grains starts compacting then it turns to dense clouds, planetary ring dust and circumstellar dust. Dust grains are mainly silicate particles. Dust plays a major role in our solar system, for example in zodiacal light, Saturn's B ring spokes, planetary rings at Jovian planets and comets. Observations and measurements of cosmic dust in different regions of universe provide an important insight into the Universe's recycling processes. Astronomers consider dust in its most recycled state. Cosmic dust have radiative properties by which they can be detected. Cosmic dusts are classified as intergalactic dusts, interstellar dusts and planetary rings. A planetary ring is a ring of cosmic dust and other small particles orbiting around a planet in flat disc shape. All of the Jovian planets in our solar system have rings. But the most notable one is the Saturn's ring which is the brightest one. In March 2008 a report suggested that the Saturn's moon Rhea may have its own tenuous ring system. The ring swirling around Saturn consists of chunks of ice and dust. Most rings were thought to be unstable and to dissipate over course of tens or hundreds of millions of years but it now appears that Saturn's rings might be older than that. The dust particles in the ring collide with each other and are subjected to forces other than gravity of its own planet. Such collisions and extra forces tend to spread out the rings. Pluto is not known to have any ring system but some Astronomers believe that New Horizons probe might find a ring system when it visits in 2015.It is also predicted that Phobos, a moon of Mars will break up and form into a planetary ring

  17. Radio-Frequency Plasma Cleaning of a Penning Malmberg Trap

    NASA Technical Reports Server (NTRS)

    Sims, William Herbert, III; Martin, James; Pearson, J. Boise; Lewis, Raymond

    2005-01-01

    Radio-frequency-generated plasma has been demonstrated to be a promising means of cleaning the interior surfaces of a Penning-Malmberg trap that is used in experiments on the confinement of antimatter. {Such a trap was reported in Modified Penning-Malmberg Trap for Storing Antiprotons (MFS-31780), NASA Tech Briefs, Vol. 29, No. 3 (March 2005), page 66.} Cleaning of the interior surfaces is necessary to minimize numbers of contaminant atoms and molecules, which reduce confinement times by engaging in matter/antimatter-annihilation reactions with confined antimatter particles. A modified Penning-Malmberg trap like the one described in the cited prior article includes several collinear ring electrodes (some of which are segmented) inside a tubular vacuum chamber, as illustrated in Figure 1. During operation of the trap, a small cloud of charged antiparticles (e.g., antiprotons or positrons) is confined to a spheroidal central region by means of a magnetic field in combination with DC and radiofrequency (RF) electric fields applied via the electrodes. In the present developmental method of cleaning by use of RF-generated plasma, one evacuates the vacuum chamber, backfills the chamber with hydrogen at a suitable low pressure, and uses an RF-signal generator and baluns to apply RF voltages to the ring electrodes. Each ring is excited in the polarity opposite that of the adjacent ring. The electric field generated by the RF signal creates a discharge in the low-pressure gas. The RF power and gas pressure are adjusted so that the plasma generated in the discharge (see Figure 2) physically and chemically attacks any solid, liquid, and gaseous contaminant layers on the electrode surfaces. The products of the physical and chemical cleaning reactions are gaseous and are removed by the vacuum pumps.

  18. High-speed separation of proteins by microchip electrophoresis using a polyethylene glycol-coated plastic chip with a sodium dodecyl sulfate-linear polyacrylamide solution.

    PubMed

    Nagata, Hideya; Tabuchi, Mari; Hirano, Ken; Baba, Yoshinobu

    2005-07-01

    In this paper, we describe a method for size-based electrophoretic separation of sodium dodecyl sulfate (SDS)-protein complexes on a polymethyl methacrylate (PMMA) microchip, using a separation buffer solution containing SDS and linear polyacrylamide as a sieving matrix. We developed optimum conditions under which protein separations can be performed, using polyethylene glycol (PEG)-coated polymer microchips and electrokinetic sample injection. We studied the performance of protein separations on the PEG-coated PMMA microchip. The electrophoretic separation of proteins (21.5-116.0 kDa) was completed with separation lengths of 3 mm, achieved within 8 s on the PEG-coated microchip. This high-speed method may be applied to protein separations over a large range of molecular weight, making the PEG-coated microchip approach applicable to high-speed proteome analysis systems.

  19. MIGRATION OF SMALL MOONS IN SATURN's RINGS

    SciTech Connect

    Bromley, Benjamin C.; Kenyon, Scott J. E-mail: skenyon@cfa.harvard.edu

    2013-02-20

    The motions of small moons through Saturn's rings provide excellent tests of radial migration models. In theory, torque exchange between these moons and ring particles leads to radial drift. We predict that moons with Hill radii r {sub H} {approx} 2-24 km should migrate through the A ring in 1000 yr. In this size range, moons orbiting in an empty gap or in a full ring eventually migrate at the same rate. Smaller moons or moonlets-such as the propellers-are trapped by diffusion of disk material into corotating orbits, creating inertial drag. Larger moons-such as Pan or Atlas-do not migrate because of their own inertia. Fast migration of 2-24 km moons should eliminate intermediate-size bodies from the A ring and may be responsible for the observed large-radius cutoff of r {sub H} {approx} 1-2 km in the size distribution of the A ring's propeller moonlets. Although the presence of Daphnis (r {sub H} Almost-Equal-To 5 km) inside the Keeler gap challenges this scenario, numerical simulations demonstrate that orbital resonances and stirring by distant, larger moons (e.g., Mimas) may be important factors. For Daphnis, stirring by distant moons seems the most promising mechanism to halt fast migration. Alternatively, Daphnis may be a recent addition to the ring that is settling into a low inclination orbit in {approx}10{sup 3} yr prior to a phase of rapid migration. We provide predictions of observational constraints required to discriminate among possible scenarios for Daphnis.

  20. Acoustic bubble traps

    NASA Astrophysics Data System (ADS)

    Geisler, Reinhard; Kurz, Thomas; Lauterborn, Werner

    2000-07-01

    A small, oscillating bubble in a liquid can be trapped in the antinode of an acoustic standing wave field. Bubble stability is required for the study of single bubble sonoluminescence (SBSL). The properties of the acoustic resonator are essential for the stable trapping of sonoluminescing bubbles. Resonators can be chosen according to the intended application: size and geometry can be varied in a wide range. In this work, the acoustic responses of different resonators were measured by means of holographic interferometry, hydrophones and a laser vibrometer. Also, high-speed photography was used to observe the bubble dynamics. Several single, stable sonoluminescent bubbles were trapped simultaneously within an acoustic resonator in the pressure antinodes of a higher harmonic mode (few bubble sonoluminescence, FBSL).

  1. Thermoelectrically cooled water trap

    DOEpatents

    Micheels, Ronald H.

    2006-02-21

    A water trap system based on a thermoelectric cooling device is employed to remove a major fraction of the water from air samples, prior to analysis of these samples for chemical composition, by a variety of analytical techniques where water vapor interferes with the measurement process. These analytical techniques include infrared spectroscopy, mass spectrometry, ion mobility spectrometry and gas chromatography. The thermoelectric system for trapping water present in air samples can substantially improve detection sensitivity in these analytical techniques when it is necessary to measure trace analytes with concentrations in the ppm (parts per million) or ppb (parts per billion) partial pressure range. The thermoelectric trap design is compact and amenable to use in a portable gas monitoring instrumentation.

  2. Three-dimensional parallel vortex rings in Bose-Einstein condensates

    SciTech Connect

    Crasovan, Lucian-Cornel; Perez-Garcia, Victor M.; Danaila, Ionut; Mihalache, Dumitru; Torner, Lluis

    2004-09-01

    We construct three-dimensional structures of topological defects hosted in trapped wave fields, in the form of vortex stars, vortex cages, parallel vortex lines, perpendicular vortex rings, and parallel vortex rings, and we show that the latter exist as robust stationary, collective states of nonrotating Bose-Einstein condensates. We discuss the stability properties of excited states containing several parallel vortex rings hosted by the condensate, including their dynamical and structural stability.

  3. Sensitive detection of influenza viruses with Europium nanoparticles on an epoxy silica sol-gel functionalized polycarbonate-polydimethylsiloxane hybrid microchip.

    PubMed

    Liu, Jikun; Zhao, Jiangqin; Petrochenko, Peter; Zheng, Jiwen; Hewlett, Indira

    2016-12-15

    In an effort to develop new tools for diagnosing influenza in resource-limited settings, we fabricated a polycarbonate (PC)-polydimethylsiloxane (PDMS) hybrid microchip using a simple epoxy silica sol-gel coating/bonding method and employed it in sensitive detection of influenza virus with Europium nanoparticles (EuNPs). The incorporation of sol-gel material in device fabrication provided functionalized channel surfaces ready for covalent immobilization of primary antibodies and a strong bonding between PDMS substrates and PC supports without increasing background fluorescence. In microchip EuNP immunoassay (µENIA) of inactivated influenza viruses, replacing native PDMS microchips with hybrid microchips allowed the achievement of a 6-fold increase in signal-to-background ratio, a 12-fold and a 6-fold decreases in limit-of-detection (LOD) in influenza A and B tests respectively. Using influenza A samples with known titers, the LOD of influenza µENIA on hybrid microchips was determined to be ~10(4) TCID50 titer/mL and 10(3)-10(4) EID50 titer/mL. A comparison test indicated that the sensitivity of influenza µENIA enhanced using the hybrid microchips even surpassed that of a commercial laboratory influenza ELISA test. In addition to the sensitivity improvement, assay variation was clearly reduced when hybrid microchips instead of native PDMS microchips were used in the µENIA tests. Finally, infectious reference viruses and nasopharyngeal swab patient specimens were successfully tested using μENIA on hybrid microchip platforms, demonstrating the potential of this unique microchip nanoparticle assay in clinical diagnosis of influenza. Meanwhile, the tests showed the necessity of using nucleic acid confirmatory tests to clarify ambiguous test results obtained from prototype or developed point-of-care testing devices for influenza diagnosis.

  4. Slowing of Vortex Rings

    NASA Astrophysics Data System (ADS)

    Donnelly, Russell; Bolster, Diogo; Hershberger, Robert

    2008-11-01

    We have investigated the slowing of vortex rings in water which are created with very thin cores. We find that these rings propagate with no measurable change in diameter or core size. The drag appears to be the result of viscous forces on the core. A simple model for this drag describes experimental data in terms of a drag coefficient, which depends only on Reynolds number. Barenghi's group at Newcastle found that the translational velocity of a ring in an inviscid fluid perturbed by Kelvin waves decreases with increasing amplitude of Kelvin waves. This suggests that the velocity of vortex rings in a viscous fluid may well depend on the amplitude of Kelvin waves at the time of formation. Rings with substantial amplitude of Kelvin waves will be expected to move more slowly than rings with little or no Kelvin wave amplitude. We present experimental data confirming this suggestion.

  5. The Reusable Astronomy Portal (TRAP)

    NASA Astrophysics Data System (ADS)

    Donaldson, T.; Rogers, A.; Wallace, G.

    2012-09-01

    The Reusable Astronomy Portal (TRAP) aims to provide a common platform for rapidly deploying Astronomy Archives to the web. TRAP is currently under development for both the VAO Data Discovery Portal and the MAST Multi-Mission Portal (Figure 1). TRAP consists of 2 major software packages: the TRAP Client and the TRAP Server. The TRAP framework allows developers to deploy the Server, connect to data resources, then focus on building custom tools for the Client. TRAP is built upon proven industry technologies including the Ext/JS JavaScript Component Library, Mono.NET Web Services, and JSON message based APIs. The multi-layered architecture of TRAP decouples each layer: Client, Service and Data Access, enabling each to evolve independently over time. Although currently deployed to provide astronomy science data access, the TRAP architecture is flexible enough to thrive in any distributed data environment.

  6. Feasibility of capillary liquid chromatography/microchip atmospheric pressure photoionization mass spectrometry in analyzing anabolic steroids in urine samples.

    PubMed

    Ahonen, Linda L; Haapala, Markus; Saarela, Ville; Franssila, Sami; Kotiaho, Tapio; Kostiainen, Risto

    2010-04-15

    We examined the feasibility of capillary liquid chromatography/microchip atmospheric pressure photoionization tandem mass spectrometry (capLC/microAPPI-MS/MS) for the analysis of anabolic steroids in human urine. The urine samples were pretreated by enzymatic hydrolysis (with beta-glucuronidase from Helix pomatia), and the compounds were liquid-liquid extracted with diethyl ether. After separation the compounds were vaporized by microchip APPI, photoionized by a 10 eV krypton discharge lamp, and detected by selected reaction monitoring. The capLC/microAPPI-MS/MS method showed good sensitivity with detection limits at the level of 1.0 ng mL(-1), good linearity with correlation coefficients between 0.9954 and 0.9990, and good repeatability with relative standard deviations below 10%. These results demonstrate that microchip APPI combined with capLC/MS/MS provides a new potential method for analyzing non-polar and neutral compounds in biological samples.

  7. A general microchip surface modification approach using a spin-coated polymer resist film doped with hydroxypropyl cellulose.

    PubMed

    Sun, Xiuhua; Yang, Weichun; Geng, Yanli; Woolley, Adam T

    2009-04-07

    We have developed a simple and effective method for surface modification of polymer microchips by entrapping hydroxypropyl cellulose (HPC) in a spin-coated thin film on the surface. Poly(methyl methacrylate-8.5-methacrylic acid), a widely available commercial resist formulation, was utilized as a matrix for dissolving HPC and providing adherence to native polymer surfaces. Various amounts of HPC (0.1-2.0%) dissolved in the copolymer and spun on polymer surfaces were evaluated. The modified surfaces were characterized by contact angle measurement, X-ray photoelectron spectroscopy and atomic force microscopy. The developed method was applied on both poly(methyl methacrylate) and cyclic olefin copolymer microchips. A fluorescently labeled myoglobin digest, binary protein mixture, and human serum sample were all separated in these surface-modified polymer microdevices. Our work exhibits an easy and reliable way to achieve favorable biomolecular separation performance in polymer microchips.

  8. A general microchip surface modification approach using a spin-coated polymer resist film doped with hydroxypropyl cellulose

    PubMed Central

    Sun, Xiuhua; Yang, Weichun; Geng, Yanli; Woolley, Adam T.

    2009-01-01

    We have developed a simple and effective method for surface modification of polymer microchips by entrapping hydroxypropyl cellulose (HPC) in a spin-coated thin film on the surface. Poly(methyl methacrylate-8.5-methacrylic acid), a widely available commercial resist formulation, was utilized as a matrix for dissolving HPC and providing adherence to native polymer surfaces. Various amounts of HPC (0.1–2.0%) dissolved in the copolymer and spun on polymer surfaces were evaluated. The modified surfaces were characterized by contact angle measurement, X-ray photoelectron spectroscopy and atomic force microscopy. The developed method was applied on both poly(methyl methacrylate) and cyclic olefin copolymer microchips. A fluorescently labeled myoglobin digest, binary protein mixture, and human serum sample were all separated in these surface-modified polymer microdevices. Our work exhibits an easy and reliable way to achieve favorable biomolecular separation performance in polymer microchips. PMID:19294306

  9. Radioactive gold ring dermatitis

    SciTech Connect

    Miller, R.A.; Aldrich, J.E. )

    1990-08-01

    A superficial squamous cell carcinoma developed in a woman who wore a radioactive gold ring for more than 30 years. Only part of the ring was radioactive. Radiation dose measurements indicated that the dose to basal skin layer was 2.4 Gy (240 rad) per week. If it is assumed that the woman continually wore her wedding ring for 37 years since purchase, she would have received a maximum dose of approximately 4600 Gy.

  10. Measurement of Trap Length for an Optical Trap

    NASA Technical Reports Server (NTRS)

    Wrbanek, Susan Y.

    2009-01-01

    The trap length along the beam axis for an optical trap formed with an upright, oil-immersion microscope was measured. The goals for this effort were twofold. It was deemed useful to understand the depth to which an optical trap can reach for purposes of developing a tool to assist in the fabrication of miniature devices. Additionally, it was desired to know whether the measured trap length favored one or the other of two competing theories to model an optical trap. The approach was to trap a microsphere of known size and mass and raise it from its initial trap position. The microsphere was then dropped by blocking the laser beam for a pre-determined amount of time. Dropping the microsphere in a free-fall mode from various heights relative to the coverslip provides an estimate of how the trapping length changes with depth in water in a sample chamber on a microscope slide. While it was not possible to measure the trap length with sufficient precision to support any particular theory of optical trap formation, it was possible to find regions where the presence of physical boundaries influenced optical traps, and determine that the trap length, for the apparatus studied, is between 6 and 7 m. These results allow more precise control using optical micromanipulation to assemble miniature devices by providing information about the distance over which an optical trap is effective.

  11. Saturn's E ring revisited

    NASA Astrophysics Data System (ADS)

    Feibelman, W. A.; Klinglesmith, D. A.

    1980-07-01

    Images of the E ring of Saturn obtained by the image processing of photographs of the 1966 edge-on presentation of the planet's ring plane are presented. Two methods of image enhancement were used: scanning with an image quantizer operated in the derivative mode to enhance contrast and computerized subtraction of a circularly symmetric image of the overexposed Saturn disk. Further photographic and CCD observation confirming the existence of the ring extending to twice the diameter of the A ring, which was not detected by the Pioneer 11 imaging photopolarimeter, is indicated.

  12. Jupiter's Ring Halo

    NASA Technical Reports Server (NTRS)

    1997-01-01

    A mosaic of four images taken through the clear filter (610 nanometers) of the solid state imaging (CCD) system aboard NASA's Galileo spacecraft on November 8, 1996, at a resolution of approximately 46 kilometers (km) per picture element (pixel) along the rings; however, because the spacecraft was only about 0.5 degrees above the ring plane, the image is highly foreshortened in the vertical direction. The images were obtained when Galileo was in Jupiter's shadow peering back toward the Sun; the ring was approximately 2,300,000 kilometers (km) away. The arc on the far right of the image is produced by sunlight scattered by small particles comprising Jupiter's upper atmospheric haze. The ring also efficiently scatters light, indicating that much of its brightness is due to particles that are microns or less in diameter. Such small particles are believed to have human-scale lifetimes, i.e., very brief compared to the solar system's age.

    Jupiter's ring system is composed of three parts -- a flat main ring, a lenticular halo interior to the main ring, and the gossamer ring, which lies exterior to the main ring. The near and far arms of Jupiter's main ring extend horizontally across the mosaic, joining together at the ring's ansa, on the far left side of the figure. The near arm of the ring appears to be abruptly truncated close to the planet, at the point where it passes into Jupiter's shadow.

    A faint mist of particles can be seen above and below the main rings; this vertically extended, toroidal 'halo' is unusual in planetary rings, and is probably caused by electromagnetic forces which can push small grains out of the ring plane. Halo material is present across this entire image, implying that it reaches more than 27,000 km above the ring plane. Because of shadowing, the halo is not visible close to Jupiter in the lower right part of the mosaic. In order to accentuate faint features in the image, different brightnesses are shown through color, with the brightest

  13. Extrinsic Fabry-Perot interferometry for noncontact temperature control of nanoliter-volume enzymatic reactions in glass microchips.

    PubMed

    Easley, Christopher J; Legendre, Lindsay A; Roper, Michael G; Wavering, Thomas A; Ferrance, Jerome P; Landers, James P

    2005-02-15

    Optical fiber extrinsic Fabry-Perot interferometry (EFPI) was investigated as a noncontact temperature sensor and utilized for regulating the temperature of small-volume solutions in microchips. Interference pattern analysis determined the optical path lengths (OPL) associated with reflections from various surfaces on or in the microchip, in particular, from gold sputtered on the bottom of a microchannel. Since OPL is directly proportional to refractive index, which is dependent on solution temperature, the EFPI sensor was capable of noncontact monitoring of solution temperature simply from alterations in the measured path length. Calibration of the sensor against a thermocouple was performed while heating the microchip in a noncontact manner with an IR lamp. The combination of EFPI temperature sensor, IR-mediated heating, and air cooling allowed a fully noncontact system for small-volume temperature control in microchip structures, and its utility was illustrated by optimal digestion of DNA by a temperature-dependent restriction endonuclease in 320 nL. The functionality and simplicity of the microchip EFPI temperature sensor was enhanced by replacing the prebonding sputtered gold with a tunable, chemically plated semireflective silver coating created in situ after chip fabrication. This provided an 8-fold improvement in the lowest detectable temperature change (deltaT = 0.1 degrees C), facilitated primarily by enhanced reflection from both the bottom and top surfaces of the microchannel. This approach for controlling micro- and nanoscale reactions--with heating, cooling, and temperature control being carried out in a completely noncontact fashion--provides an accurate and sensitive method for executing chemical and biochemical reactions in microchips.

  14. Wave Modes Trapped in Rotating Nonlinear Potentials

    NASA Astrophysics Data System (ADS)

    Li, Yongyao; Pang, Wei; Malomed, Boris A.

    We study modes trapped in a rotating ring with the local strength of the nonlinearity modulated as \\cos (2θ ) , where θ is the azimuthal angle. This modulation pattern may be of three different types: self-focusing (SF), self-defocusing (SDF), and alternating SF-SDF. The model, based on the nonlinear Schrödinger (NLS) equation with periodic boundary conditions, applies to the light propagation in a twisted pipe waveguide, and to a Bose-Einstein condensate (BEC) loaded into a toroidal trap, under the action of the rotating nonlinear pseudopotential induced by means of the Feshbach resonance in an inhomogeneous external field. This is the difference from the recently considered similar setting with the rotating linear potential. In the SF, SDF, and alternating regimes, four, three, and five different types of stable trapped modes are identified, respectively: even, odd, second-harmonic (2H), symmetry-breaking, and 2H-breaking ones. The shapes and stability of these modes, together with transitions between them, are investigated in the first rotational Brillouin zone. Ground-state modes are identified in each regime. Boundaries between symmetric and asymmetric modes are also found in an analytical form, by means of a two-mode approximation.

  15. Saturn Ring Radiation Environment for the Cassini Grand Finale Orbits

    NASA Astrophysics Data System (ADS)

    Cooper, John F.; Kollmann, Peter; Johnson, Robert E.; Roussos, Elias; Sittler, Edward C.; Sturner, Steven J.

    2016-10-01

    Grand Finale (proximal) orbits of Cassini from April to September 2017 will provide an unprecedented opportunity for further in-situ exploration of the energetic radiation environment primarily arising from galactic cosmic ray interactions with the main rings. Improved modeling of these interactions contributes to ring mass properties, radiation chemistry, and source modeling for trapped radiation within and beyond the rings. Our new GEANT simulations show that these interactions produce very substantial fluxes of secondary gamma rays, neutrons, electrons, protons, and more short-lived particles. Cosmic ray albedo neutron decay from ring neutron emissions provides the primary source of trapped protons near and above 10 MeV in the radiation belts extending from beyond the F ring to the orbit of Tethys. Fluxes of these high-energy trapped protons increased as expected with declining solar activity from 2004 through 2009, consistent with decreasing modulation of the galactic cosmic ray protons and heavier ions by the solar wind. In 2017 solar activity and modulation will again be declining from earlier maximum levels in 2012 - 2014, while solar illumination of the rings will be near solstice levels. There may then be similarities in the ring radiation and plasma environment to conditions in 2004. In comparison, the 1979 traversal of the main rings by Pioneer 11 occurred during peak solar activity but declining cosmic ray flux. The questions are then what radiation environment we might expect to find during the Grand Finale orbits, how would the Cassini MIMI LEMMS sensor respond to this environment, and how might these new measurements change our understanding of the rings? During SOI flyover of the rings, LEMMS nominal data showed intensities higher than those from Pioneer 11 to an extent that cannot be explained by the updated interaction model. LEMMS more likely responded to penetrating high-energy radiation at energies outside its nominal ranges for electrons and

  16. Modified spiral wound retaining ring

    NASA Technical Reports Server (NTRS)

    Lawson, A. G. (Inventor)

    1980-01-01

    A spiral wound retaining ring with angled ends is described. The ring is crimped at the same angle as the ring ends to maintain a constant thickness dimension. The angling of the ends of the ring and crimp allow the ends to be positioned closer together while maintaining enough clearance to enable insertion and removal of the ring. By reducing the separation distance between the ends a stronger ring results since the double layer area of the ring is maximized.

  17. WATER-TRAPPED WORLDS

    SciTech Connect

    Menou, Kristen

    2013-09-01

    Although tidally locked habitable planets orbiting nearby M-dwarf stars are among the best astronomical targets to search for extrasolar life, they may also be deficient in volatiles and water. Climate models for this class of planets show atmospheric transport of water from the dayside to the nightside, where it is precipitated as snow and trapped as ice. Since ice only slowly flows back to the dayside upon accumulation, the resulting hydrological cycle can trap a large amount of water in the form of nightside ice. Using ice sheet dynamical and thermodynamical constraints, I illustrate how planets with less than about a quarter the Earth's oceans could trap most of their surface water on the nightside. This would leave their dayside, where habitable conditions are met, potentially dry. The amount and distribution of residual liquid water on the dayside depend on a variety of geophysical factors, including the efficiency of rock weathering at regulating atmospheric CO{sub 2} as dayside ocean basins dry up. Water-trapped worlds with dry daysides may offer similar advantages as land planets for habitability, by contrast with worlds where more abundant water freely flows around the globe.

  18. Water-trapped Worlds

    NASA Astrophysics Data System (ADS)

    Menou, Kristen

    2013-09-01

    Although tidally locked habitable planets orbiting nearby M-dwarf stars are among the best astronomical targets to search for extrasolar life, they may also be deficient in volatiles and water. Climate models for this class of planets show atmospheric transport of water from the dayside to the nightside, where it is precipitated as snow and trapped as ice. Since ice only slowly flows back to the dayside upon accumulation, the resulting hydrological cycle can trap a large amount of water in the form of nightside ice. Using ice sheet dynamical and thermodynamical constraints, I illustrate how planets with less than about a quarter the Earth's oceans could trap most of their surface water on the nightside. This would leave their dayside, where habitable conditions are met, potentially dry. The amount and distribution of residual liquid water on the dayside depend on a variety of geophysical factors, including the efficiency of rock weathering at regulating atmospheric CO2 as dayside ocean basins dry up. Water-trapped worlds with dry daysides may offer similar advantages as land planets for habitability, by contrast with worlds where more abundant water freely flows around the globe.

  19. Steam trap monitor

    DOEpatents

    Ryan, Michael J.

    1988-01-01

    A steam trap monitor positioned downstream of a steam trap in a closed steam system includes a first sensor (the combination of a hot finger and thermocouple well) for measuring the energy of condensate and a second sensor (a cold finger) for measuring the total energy of condensate and steam in the line. The hot finger includes one or more thermocouples for detecting condensate level and energy, while the cold finger contains a liquid with a lower boiling temperature than that of water. Vapor pressure from the liquid is used to do work such as displacing a piston or bellows in providing an indication of total energy (steam+condensate) of the system. Processing means coupled to and responsive to outputs from the thermocouple well hot and cold fingers subtracts the condensate energy as measured by the hot finger and thermocouple well from the total energy as measured by the cold finger to provide an indication of the presence of steam downstream from the trap indicating that the steam trap is malfunctioning.

  20. Practical axial optical trapping

    PubMed Central

    Mack, A. H.; Schlingman, D. J.; Regan, L.; Mochrie, S. G. J.

    2012-01-01

    We describe a new method for calibrating optical trapping measurements in which tension is applied in the direction of the laser beam to a molecule tethered between a surface and an optically trapped bead. Specifically, we present a generally-applicable procedure for converting from the measured scattering intensity and the measured stage displacement to applied tension and bead-coverslip separation, using measurements of the light intensity scattered from an untethered, trapped bead. Our calibration accounts for a number of effects, including aberrations and the interference of forward-reflected bead-scattered light with the trapping beam. To demonstrate the accuracy of our method, we show measurements of the DNA force-versus-extension relation using a range of laser intensities, and show that these measurements match the expected extensible wormlike-chain (WLC) behavior. Finally, we also demonstrate a force-clamp, in which the tension in a tether is held fixed while the extension varies as a result of molecular events. PMID:23126750

  1. Rotating Saddle Paul Trap.

    ERIC Educational Resources Information Center

    Rueckner, Wolfgang; And Others

    1995-01-01

    Describes a demonstration in which a ball is placed in an unstable position on a saddle shape. The ball becomes stable when it is rotated above some threshold angular velocity. The demonstration is a mechanical analog of confining a particle in a "Paul Trap". (DDR)

  2. Recent advances in enhancing the sensitivity of electrophoresis and electrochromatography in capillaries and microchips (2014-2016).

    PubMed

    Breadmore, Michael C; Wuethrich, Alain; Li, Feng; Phung, Sui Ching; Kalsoom, Umme; Cabot, Joan M; Tehranirokh, Masoomeh; Shallan, Aliaa I; Abdul Keyon, Aemi S; See, Hong Heng; Dawod, Mohamed; Quirino, Joselito P

    2017-01-01

    One of the most cited limitations of capillary (and microchip) electrophoresis is the poor sensitivity. This review continues to update this series of biennial reviews, first published in Electrophoresis in 2007, on developments in the field of on-line/in-line concentration methods in capillaries and microchips, covering the period July 2014-June 2016. It includes developments in the field of stacking, covering all methods from field amplified sample stacking and large volume sample stacking, through to isotachophoresis, dynamic pH junction, and sweeping. Attention is also given to on-line or in-line extraction methods that have been used for electrophoresis.

  3. Separation of motile sperm for in vitro fertilization from frozen-thawed bull semen using progesterone induction on a microchip.

    PubMed

    Li, Jingchun; Ning, Bolin; Cao, Xinyan; Luo, Yinghua; Guo, Li; Wei, Guosheng; Liu, Shengjun; Zhang, Ying; Zhang, Aizhong; Wu, Rui; Li, Yanbing

    2016-09-01

    This study presents a novel method for the separation of motile sperm from non-progressive motile and immotile sperm and in vitro Fertilization (IVF). This separation of bull sperm was accomplished by inducing chemotaxis along a progesterone release agent in a 7.5-mm microchannel microchip composed of a biocompatible polydimethysiloxane layer and a glass gradient. The selected sperm was applied directly for IVF. In the first experiment, we tested the effect of different lengths of microchannnel (5mm, 7.5mm and 10mm) on quality parameter of separated sperm. The results showed that separated sperm using 7.5-mm microchannel chip were improved in sperm motility, swimming velocity, and beat frequency compared with other groups. In the second experiment, a medium containing sperm from swim-up method and outlet reservoir of our 7.5-mm microchannel chip was collected and mitochondrial activity of the sperm was determined by fluorescence microscopy. The sperm from the microchip had higher mitochondria activity (47.6%±6.0%) than the sperm from the swim-up method (23.6%±4.7%) (P<0.05). There were significant differences in rate of acrosome intactness between the swim-up method and the microchip (36.0%±4.1% vs. 66.8±2.1%, respectively, P<0.05). In the third experiment, we compared sperm penetration in the microchip-IVF system with a standard IVF method (droplet-IVF). The microchip-IVF group had the highest percentages of oocytes penetrated (82.2%±1.6% vs. 63.5%±2.4%) and monospermic oocytes (67.8%±3.4% vs. 42.4%±1.5%). In addition, early developmental competence of oocytes to the blastocyst stage was higher when the oocytes were inseminated in the microchip-IVF system compared with those inseminated in a standard droplet-IVF system. These results demonstrate that our microchip based on a sperm chemotaxis system is useful for motile sperm separation from frozen-thawed bull semen for IVF. Therefore, the optimized microchip system provides a good opportunity to sort

  4. A novel CE microchip with micro pillars column & double-L injection design for Capacitance Coupled Contactless Conductivity detection technology

    NASA Astrophysics Data System (ADS)

    Wang, Yineng; Messina, Walter; Cao, Xi; Hogan, Anna; van Zalen, Ed; Moore, Eric

    2016-10-01

    This novel capillary electrophoresis microchip, or also known as μTAS (micro total analysis system) was designed to separate complex aqueous based compounds, similar to commercial CE & microchip (capillary electrophoresis) systems, but more compact. This system can be potentially used for mobile/portable chemical analysis equipment. Un-doped silicon wafer & ultra-thin borofloat glass (Pyrex) wafers have been used to fabricate the device. Double-L injection feature, micro pillars column, bypass separation channel & hybrid- referenced C4D electrodes were designed to achieve a high SNR (signal to noise ratio), easy- separation, for a durable and reusable μTAS for CE use.

  5. Use of epoxy-embedded electrodes to integrate electrochemical detection with microchip-based analysis systems.

    PubMed

    Selimovic, Asmira; Johnson, Alicia S; Kiss, István Z; Martin, R Scott

    2011-04-01

    A new method of fabricating electrodes for microchip devices that involves the use of Teflon molds and a commercially available epoxy to embed electrodes of various sizes and compositions is described. The resulting epoxy base can be polished to generate a fresh electrode and sealed against poly(dimethylsiloxane) (PDMS)-based fluidic structures. Microchip-based flow injection analysis was used to characterize the epoxy-embedded electrodes. It was shown that gold electrodes can be amalgamated with liquid mercury and the resulting mercury/gold electrode is used to selectively detect glutathione from lysed red blood cells. The ability to encapsulate multiple electrode materials of differing compositions enabled the integration of microchip electrophoresis with electrochemical detection. Finally, a unique feature of this approach is that the electrode connection is made from the bottom of the epoxy base. This enables the creation of three-dimensional gold pillar electrodes (65 μm in diameter and 27 μm in height) that can be integrated within a fluidic network. As compared with the use of a flat electrode of a similar diameter, the use of the pillar electrode led to improvements in both the sensitivity (72.1 pA/μM for the pillar versus 4.2 pA/μM for the flat electrode) and limit of detection (20 nM for the pillar versus 600 nM for the flat electrode), with catechol being the test analyte. These epoxy-embedded electrodes hold promise for the creation of inexpensive microfluidic devices that can be used to electrochemically detect biologically important analytes in a manner where the electrodes can be polished and a fresh electrode surface is generated as desired.

  6. In vitro and in vivo evaluation of ultrananocrystalline diamond as an encapsulation layer for implantable microchips.

    PubMed

    Chen, Ying-Chieh; Tsai, Che-Yao; Lee, Chi-Young; Lin, I-Nan

    2014-05-01

    Thin ultrananocrystalline diamond (UNCD) films were evaluated for use as hermetic and bioinert encapsulating coatings for implantable microchips, where the reaction to UNCD in vitro and in vivo tissue was investigated. Leakage current tests showed that depositing UNCD coatings, which were conformally grown in (1% H2) Ar/CH4 plasma, on microchips rendered the surface electrochemically inactive, i.e. with a very low leakage current density (2.8×10(-5)Acm(-2) at -1V and 1.9×10(-3)Acm(-2) at ±5V) ex vivo. The impact of UNCD with different surface modifications on the growth and activation of macrophages was compared to that of standard-grade polystyrene. Macrophages attached to oxygen-terminated UNCD films down-regulated their production of cytokines and chemokines. Moreover, with UNCD-coated microchips, which were implanted subcutaneously into BALB/c mice for up to 3months, the tissue reaction and capsule formation was significantly decreased compared to the medical-grade titanium alloy Ti-6Al-4V and bare silicon. Additionally, the leakage current density, elicited by electrochemical activity, on silicon chips encapsulated in oxygen-terminated UNCD coatings remained at the low level of 2.5×10(-3)Acm(-2) at 5V for up to 3months in vivo, which is half the level of those encapsulated in hydrogen-terminated UNCD coatings. Thus, controlling the surface properties of UNCDs makes it possible to manipulate the in vivo functionality and stability of implantable devices so as to reduce the host inflammatory response following implantation. These observations suggest that oxygen-terminated UNCDs are promising candidates for use as encapsulating coatings for implantable microelectronic devices.

  7. Microchip laser based on Yb:YAG/V:YAG monolith crystal

    NASA Astrophysics Data System (ADS)

    Nejezchleb, Karel; Šulc, Jan; Jelínková, Helena; Škoda, Václav

    2016-03-01

    V:YAG crystal was investigated as a passive Q-switch of longitudinally diode-pumped microchip laser, emitting radiation at wavelength 1030.5 nm. This laser was based on diffusion bonded monolith crystal (diameter 3 mm) which combines in one piece an active laser part (Yb:YAG crystal, 10 at.% Yb/Y, 3 mm long) and saturable absorber (V:YAG crystal, 2 mm long, initial transmission 86 % @ 1031 nm). The microchip resonator consisted of dielectric mirrors directly deposited on the monolith surfaces (pump mirror HT @ 968 nm and HR @ 1031 nm on Yb:YAG part, output coupler with reflection 55 % @ 1031 nm on the V:YAG part). For longitudinal CW pumping of Yb:YAG part, a fibre coupled (core diameter 100 μm, NA = 0.22, emission @ 968 nm) laser diode was used. The laser threshold was 3.8W. The laser slope efficiency for output mean in respect to incident pumping was 16 %. The linearly polarized generated transversal intensity beam profile was close to the fundamental Gaussian mode. The generated pulse length, stable and mostly independent on pumping power, was equal to 1.3 ns (FWHM). The single pulse energy was increasing with the pumping power and for the maximum pumping 9.7W it was 78 μJ which corresponds to the pulse peak-power 56 kW. The maximum Yb:YAG/V:YAG microchip laser mean output power of 1W was reached without observable thermal roll-over. The corresponding Q-switched pulses repetition rate was 13.1 kHz.

  8. Use of epoxy-embedded electrodes to integrate electrochemical detection with microchip-based analysis systems

    PubMed Central

    Selimovic, Asmira; Johnson, Alicia S.; Kiss, István Z.; Martin, R. Scott

    2011-01-01

    A new method of fabricating electrodes for microchip devices that involves the use of Teflon molds and a commercially available epoxy to embed electrodes of various size and composition is described. The resulting epoxy base can be polished to generate a fresh electrode and sealed against PDMS-based fluidic structures. Microchip-based flow injection analysis was used to characterize the epoxy-embedded electrodes. It was shown that gold electrodes can be amalgamated with liquid mercury and the resulting mercury/gold electrode used to selectively detect glutathione from lysed red blood cells. The ability to encapsulate multiple electrode materials of differing composition enabled the integration of microchip electrophoresis with electrochemical detection. Finally, a unique feature of this approach is that the electrode connection is made from the bottom of the epoxy base. This enables the creation of three-dimensional gold pillar electrodes (65 µm in diameter and 27 µm in height) that can be integrated within a fluidic network. As compared to the use of a flat electrode of a similar diameter, the use of the pillar electrode led to improvements in both the sensitivity (72.1 pA/µM for the pillar vs. 4.2 pA/µM for the flat electrode) and limit of detection (20 nM for the pillar vs. 600 nM for the flat electrode), with catechol being the test analyte. These epoxy-embedded electrodes hold promise for the creation of inexpensive microfluidic devices that can be used to electrochemically detect biologically important analytes in a manner where the electrodes can be polished and a fresh electrode surface generated as desired. PMID:21413031

  9. Detecting thiols in a microchip device using micromolded carbon ink electrodes modified with cobalt phthalocyanine.

    PubMed

    Kuhnline, Courtney D; Gangel, Michael G; Hulvey, Matthew K; Martin, R Scott

    2006-02-01

    This paper describes the fabrication and evaluation of a chemically modified carbon ink microelectrode to detect thiols of biological interest. The detection of thiols, such as homocysteine and cysteine, is necessary to monitor various disease states. The biological implications of these thiols generate the need for miniaturized detection systems that enable portable monitoring as well as quantitative results. In this work, we utilize a microchip device that incorporates a micromolded carbon ink electrode modified with cobalt phthalocyanine to detect thiols. Cobalt phthalocyanine (CoPC) is an electrocatalyst that lowers the potential needed for the oxidation of thiols. The CoPC/carbon ink composition was optimized for the micromolding method and the resulting microelectrode was characterized with microchip-based flow injection analysis. It was found that CoPC lowers the overpotential for thiols but, as compared to direct amperometric detection, a pulsed detection scheme was needed to constantly regenerate the electrocatalyst surface, leading to improved peak reproducibility and limits of detection. Using the pulsed method, cysteine exhibited a linear response between 10-250 microM (r(2) = 0.9991) with a limit of detection (S/N = 3) of 7.5 microM, while homocysteine exhibited a linear response between 10-500 microM (r(2) = 0.9967) with a limit of detection of 6.9 microM. Finally, to demonstrate the ability to measure thiols in a biological sample using a microchip device, the CoPC-modified microelectrode was utilized for the detection of cysteine in the presence of rabbit erythrocytes.

  10. Highly efficient dynamic modification of plastic microfluidic devices using proteins in microchip capillary electrophoresis.

    PubMed

    Naruishi, Nahoko; Tanaka, Yoshihide; Higashi, Tetsuji; Wakida, Shin-ichi

    2006-10-20

    New dynamic coating agents were investigated for the manipulation of electroosmotic flow (EOF) in poly(methylmethacrylate) (PMMA) microchips. Blocking proteins designed for enzyme-linked immunosorbent assay (ELISA) applications (e.g. Block Ace and UltraBlock), and egg-white lysozyme were proposed in this study. The EOF could be enhanced, suppressed or its direction could be reversed, depending on the buffer pH and the charge on the proteins. The coating procedure is simple, requiring only filling of the microchannels with a coating solution, followed by a rinse with a running buffer solution prior to analysis. One major advantage of this method is that it is not necessary to add the coating agent to the running buffer solution. Block Ace and UltraBlock coatings were stable for at least five runs in a given microchannel without the need to condition the coating between runs other than replenishing the buffer solution after each run, i.e. the RSD values of EOF (n=5) were less than 4.3%, and there was no significant change in the EOF after 5 runs. The reproducibility of the coating procedures was found from the channel-to-channel RSD values of the EOF, and were less than 5.0% when using HEPES-Na buffer (pH 7.4) as the running buffer. Several examples of electrophoretic separations of amino acids and biogenic amines derivatized with 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F) are demonstrated in this paper. The dynamic coating method has the potential for a broad range of applications in microchip capillary electrophoresis (microchip CE) separations.

  11. PDMS microchip coated with polydopamine/gold nanoparticles hybrid for efficient electrophoresis separation of amino acids.

    PubMed

    Liang, Ru-Ping; Meng, Xiang-Ying; Liu, Chun-Ming; Qiu, Jian-Ding

    2011-11-01

    In this paper, a novel, simple, economical and environmentally friendly method based on in situ chemically induced synthesis strategy was designed and developed for the modification of a poly(dimethylsiloxane) (PDMS) microchip channel with polydopamine/gold nanoparticles (PDA/Au NPs) to create a hydrophilic and biofouling resistant surface. Dopamine as a reductant and a monomer, and HAuCl(4) as an oxidant to trigger dopamine polymerization and the source of metallic nanoparticles, were filled into the PDMS microchannel to yield in situ a well-distributed and robust PDA/Au NP coating. Au NPs were highly and uniformly dispersed in/on the PDA matrix with a narrow size distribution, as verified by scanning electron microscopy and UV-vis spectra. Compared with the native PDMS microchannel, the modified surfaces exhibited much better wettability, high stability and suppressed electroosmotic mobility, and less nonspecific adsorption towards biomolecules. The water contact angle and EOF of PDA/Au NP-coated PDMS microchip were measured to be 13° and 4.17×10(-4) cm(2)/V s, compared to those of 111° and 5.33×10(-4) cm(2)/V s from the native one, respectively. Fast and efficient separations of five amino acids such as arginine, proline, histidine, valine and threonine suggested greatly improved electrophoretic performance of the PDA/Au NP-functionalized PDMS microchips. This one-step procedure offers an effective approach for a biomimetic surface design on microfluidic chips, which is promising in high-throughput and complex biological analysis.

  12. Acousto-optical deflection-based laser beam scanning for fluorescence detection on multichannel electrophoretic microchips.

    PubMed

    Huang, Z; Munro, N; Hühmer, A F; Landers, J P

    1999-12-01

    Laser beam scanning driven by an acousto-optical deflector (AOD) is presented for multimicrochannel laser-induced fluorescence (LIF) detection during microchip-based electrophoresis. While fast laser beam scanning for LIF detection on capillary or microchannel arrays can been achieved with galvanometric scanning or a translating stage, it can also be accomplished by using acoustic waves to deflect the laser beam in a manner that is dependent on the acoustic frequency. AOD scanning differs from other approaches in that no moving parts are required, and the scan frequency is faster than conventional approaches. Using a digital/analog (D/A) converter to provide addressing voltages to a voltage/frequency converter, rapidly changing the frequency input to the AOD allows the laser beam to be addressed accurately on a microchip. With the ability to change the frequency on the nanosecond time scale, scanning rates as high as 30 Hz for Windows-based LabView programming are possible, with much faster scan rates achievable if a microprocessor-embedded system is utilized. In addition to spatial control, temporal control is easily attainable via raster scanning or random addressing, allowing for the scanning process to be self-aligning. Since the D/A output voltages drive the scanning of the laser beam over all channels, the software can define addressing voltages corresponding to the microchannel centers and, subsequently, fluorescence data can be collected from only those locations. This method allows for flexible, high-speed, self-align scanning for fluorescence detection in capillary or microchip electrophoresis and has the potential to be applied to a number of applications.

  13. An overview of the neuron ring model

    NASA Technical Reports Server (NTRS)

    Taber, Rod

    1991-01-01

    The Neuron Ring model employs an avalanche structure with two important distinctions at the neuron level. Each neuron has two memory latches; one traps maximum neuronal activation during pattern presentation, and the other records the time of latch content change. The latches filter short term memory. In the process, they preserve length 1 snapshots of activation theory history. The model finds utility in pattern classification. Its synaptic weights are first conditioned with sample spectra. The model then receives a test or unknown signal. The objective is to identify the sample closest to the test signal. Class decision follows complete presentation of the test data. The decision maker relies exclusively on the latch contents. Presented here is an overview of the Neuron Ring at the seminar level.

  14. Oligonucleotide microchips as genosensors for determinative and environmental studies in microbiology.

    PubMed Central

    Guschin, D Y; Mobarry, B K; Proudnikov, D; Stahl, D A; Rittmann, B E; Mirzabekov, A D

    1997-01-01

    The utility of parallel hybridization of environmental nucleic acids to many oligonucleotides immobilized in a matrix of polyacrylamide gel pads on a glass slide (oligonucleotide microchip) was evaluated. Oligonucleotides complementary to small-subunit rRNA sequences of selected microbial groups, encompassing key genera of nitrifying bacteria, were shown to selectively retain labeled target nucleic acid derived from either DNA or RNA forms of the target sequences. The utility of varying the probe concentration to normalize hybridization signals and the use of multicolor detection for simultaneous quantitation of multiple probe-target populations were demonstrated. PMID:9172361

  15. Microchip solid-state cylindrical vector lasers with orthogonally polarized dual laser-diode end pumping.

    PubMed

    Otsuka, Kenju; Chu, Shu-Chun

    2013-05-01

    We report a simple method for generating cylindrical vector beams directly from laser-diode (LD)-pumped microchip solid-state lasers by using dual end-pumping beams. Radially as well as azimuthally polarized vector field emissions have been generated from the common c-cut Nd:GdVO4 laser cavity merely by controlling the focus positions of orthogonally polarized LD off-axis pump beams. Hyperbolically polarized vector fields have also been observed, in which the cylindrical symmetry of vector fields is broken. Experimental results have been well reproduced by numerical simulations.

  16. Integration of ground aerogel particles as chromatographic stationary phase into microchip.

    PubMed

    Gaspar, Attila; Nagy, Andrea; Lazar, Istvan

    2011-02-18

    C16 modified and ground monolithic silica aerogel particles in submicrometer size, as a new type of stationary phase was prepared and integrated in polydimethylsiloxane (PDMS) microchip. The aerogel particles were packed into the microfluidic channel using a simple procedure, which does not require any special frit or fabrication step to retain the particles. The subnanoliter volume of samples can be transported through the porous, short length of packing with low pressure (< 3 bar). Food dyes as test components could be separated using low pressure within 6s. A 50-fold preconcentration could be achieved by retaining 100 nL volume of sample on the packing and elution with methanol.

  17. Contactless Magnetic Slip Ring

    NASA Technical Reports Server (NTRS)

    Kumagai, Hiroyuki (Inventor); Deardon, Joe D. (Inventor)

    1997-01-01

    A contactless magnetic slip ring is disclosed having a primary coil and a secondary coil. The primary and secondary coils are preferably magnetically coupled together, in a highly reliable efficient manner, by a magnetic layered core. One of the secondary and primary coils is rotatable and the contactless magnetic slip ring provides a substantially constant output.

  18. Illustration of Saturn's Rings

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This illustration shows a close-up of Saturn's rings. These rings are thought to have formed from material that was unable to form into a Moon because of tidal forces from Saturn, or from a Moon that was broken up by Saturn's tidal forces.

  19. Birth Control Ring

    MedlinePlus

    ... It? The birth control ring is a soft, flexible, doughnut-shaped ring about 2 inches (5 centimeters) in diameter. It is inserted into the vagina, where it slowly releases hormones — the chemicals the body makes to control organ function — through the vaginal wall into the ...

  20. Steroidal contraceptive vaginal rings.

    PubMed

    Sarkar, N N

    2003-06-01

    The development of steroid-releasing vaginal rings over the past three decades is reviewed to illustrate the role of this device as an effective hormonal contraceptive for women. Vaginal rings are made of polysiloxane rubber or ethylene-vinyl-acetate copolymer with an outer diameter of 54-60 mm and a cross-sectional diameter of 4-9.5 mm and contain progestogen only or a combination of progestogen and oestrogen. The soft flexible combined ring is inserted in the vagina for three weeks and removed for seven days to allow withdrawal bleeding. Progesterone/progestogen-only rings are kept in for varying periods and replaced without a ring-free period. Rings are in various stages of research and development but a few, such as NuvaRing, have reached the market in some countries. Women find this method easy to use, effective, well tolerated and acceptable with no serious side-effects. Though the contraceptive efficacy of these vaginal rings is high, acceptability is yet to be established.

  1. Smoke Ring Physics

    NASA Astrophysics Data System (ADS)

    Huggins, Elisha

    2011-11-01

    The behavior of smoke rings, tornados, and quantized vortex rings in superfluid helium has many features in common. These features can be described by the same mathematics we use when introducing Ampère's law in an introductory physics course. We discuss these common features.

  2. The Fermilab recycler ring

    SciTech Connect

    Martin Hu

    2001-07-24

    The Fermilab Recycler is a permanent magnet storage ring for the accumulation of antiprotons from the Antiproton Source, and the recovery and cooling of the antiprotons remaining at the end of a Tevatron store. It is an integral part of the Fermilab III luminosity upgrade. The following paper describes the design features, operational and commissioning status of the Recycler Ring.

  3. Smoke Ring Physics

    ERIC Educational Resources Information Center

    Huggins, Elisha

    2011-01-01

    The behavior of smoke rings, tornados, and quantized vortex rings in superfluid helium has many features in common. These features can be described by the same mathematics we use when introducing Ampere's law in an introductory physics course. We discuss these common features. (Contains 7 figures.)

  4. EBT ring physics

    SciTech Connect

    Uckan, N.A.

    1980-04-01

    This workshop attempted to evaluate the status of the current experimental and theoretical understanding of hot electron ring properties. The dominant physical processes that influence ring formation, scaling, and their optimal behavior are also studied. Separate abstracts were prepared for each of the 27 included papers. (MOW)

  5. Telemetry carrier ring and support

    NASA Technical Reports Server (NTRS)

    Wakeman, Thomas G. (Inventor)

    1992-01-01

    A telemetry carrier ring for use in a gas turbine engine includes an annular support ring connected to the engine and an annular carrier ring coupled to the support ring, each ring exhibiting different growth characteristics in response to thermal and mechanical loading. The carrier ring is coupled to the support ring by a plurality of circumferentially spaced web members which are relatively thin in an engine radial direction to provide a predetermined degree of radial flexibility. the web members have a circumferential width and straight axial line of action selected to transfer torque and thrust between the support ring and the carrier ring without substantial deflection. The use of the web members with radial flexibility provides compensation between the support ring and the carrier ring since the carrier ring grows at a different rate than the supporting ring.

  6. Jupiter's Gossamer Rings Explained.

    NASA Astrophysics Data System (ADS)

    Hamilton, D. P.

    2003-05-01

    Over the past several years, Galileo measurements and groundbased imaging have drastically improved our knowledge of Jupiter's faint ring system. We now recognize that the ring consists of four components: a main ring 7000km wide, whose inner edge blossoms into a vertically-extended halo, and a pair of more tenuous Gossamer rings, one associated with each of the small moons Thebe and Amalthea. When viewed edge on, the Gossamer rings appear as diaphanous disks whose thicknesses agree with the vertical excursions of the inclined satellites from the equatorial plane. In addition, the brightness of each Gossamer ring drops off sharply outside the satellite orbits. These correlations allowed Burns etal (1999, Science, 284, 1146) to argue convincingly that the satellites act as sources of the dusty ring material. In addition, since most material is seen inside the orbits of the source satellites, an inwardly-acting dissipative force such as Poynting-Robertson drag is implicated. The most serious problem with this simple and elegant picture is that it is unable to explain the existence of a faint swath of material that extends half a jovian radius outward from Thebe. A key constraint is that this material has the same thickness as the rest of the Thebe ring. In this work, we identify the mechanism responsible for the outward extension: it is a shadow resonance, first investigated by Horanyi and Burns (1991, JGR, 96, 19283). When a dust grain enters Jupiter's shadow, photoelectric processes shut down and the grain's electric charge becomes more negative. The electromagnetic forces associated with the varying charge cause periodic oscillations in the orbital eccentricity and semimajor axis as the orbital pericenter precesses. This results in a ring which spreads both inward and outward of its source satellite while preserving its vertical thickness - just as is observed for the Thebe ring. Predictions of the model are: i) gaps of micron-sized material interior to Thebe and

  7. Ring chromosome 4.

    PubMed Central

    McDermott, A; Voyce, M A; Romain, D

    1977-01-01

    A mentally and physically retarded boy with a 46,XY,ring (4) (p16q35) chromosome complement is described. Chromosome banding showed that the amount of chromosome material deleted from the ring chromosome 4 was minimal, apparently no more than the telomeres. Chromosomal aberrations appear to be restricted to the production of double-sized dicentric rings, and aneuploidy. The mosiacism resulting from the behavioural peculiarities of ring chromosomes is described as dynamic mosaicism. It is suggested that the clinical features associated with this ring chromosome are more likely to be the result of the effects of a diploid/monosomy 4/polysomy 4 mosaicism than to the deficiency of the telomeric regions of the chromosome. Images PMID:881718

  8. Jupiter's Rings: Sharpest View

    NASA Technical Reports Server (NTRS)

    2007-01-01

    The New Horizons spacecraft took the best images of Jupiter's charcoal-black rings as it approached and then looked back at Jupiter. The top image was taken on approach, showing three well-defined lanes of gravel- to boulder-sized material composing the bulk of the rings, as well as lesser amounts of material between the rings. New Horizons snapped the lower image after it had passed Jupiter on February 28, 2007, and looked back in a direction toward the sun. The image is sharply focused, though it appears fuzzy due to the cloud of dust-sized particles enveloping the rings. The dust is brightly illuminated in the same way the dust on a dirty windshield lights up when you drive toward a 'low' sun. The narrow rings are confined in their orbits by small 'shepherding' moons.

  9. Drop trapping in axisymmetric constrictions with arbitrary contact angle

    NASA Astrophysics Data System (ADS)

    Ratcliffe, Thomas; Davis, Robert H.

    2012-06-01

    The differential Young-Laplace equations are solved numerically with an iterative solution using the method of steepest descent to determine the shape of a drop trapped under gravity in an axisymmetric ring constriction. Prior work for non-wetting drops with a contact angle of π is extended to arbitrary values of the contact angle at the three-phase contact lines. The critical Bond number, representing a dimensionless ratio of gravitational and interfacial forces, and separating static trapping at lower Bond numbers from dynamic squeezing at higher Bond numbers, decreases with decreasing contact angle, indicating that drop squeezing occurs more easily at smaller contact angle. Indeed, a critical contact angle, which depends only on the drop-to-hole and ring-cross-section-to-hole size ratios, is found, below which all drops squeeze through the hole.

  10. Costs and benefits of trap-neuter-release and euthanasia for removal of urban cats in Oahu, Hawaii.

    PubMed

    Lohr, Cheryl A; Cox, Linda J; Lepczyk, Christopher A

    2013-02-01

    Our goal was to determine whether it is more cost-effective to control feral cat abundance with trap-neuter-release programs or trap and euthanize programs. Using STELLA 7, systems modeling software, we modeled changes over 30 years in abundance of cats in a feral colony in response to each management method and the costs and benefits associated with each method . We included costs associated with providing food, veterinary care, and microchips to the colony cats and the cost of euthanasia, wages, and trapping equipment in the model. Due to a lack of data on predation rates and disease transmission by feral cats the only benefits incorporated into the analyses were reduced predation on Wedge-tailed Shearwaters (Puffinus pacificus). When no additional domestic cats were abandoned by owners and the trap and euthanize program removed 30,000 cats in the first year, the colony was extirpated in at least 75% of model simulations within the second year. It took 30 years for trap-neuter-release to extirpate the colony. When the cat population was supplemented with 10% of the initial population size per year, the colony returned to carrying capacity within 6 years and the trap and euthanize program had to be repeated, whereas trap-neuter-release never reduced the number of cats to near zero within the 30-year time frame of the model. The abandonment of domestic cats reduced the cost effectiveness of both trap-neuter-release and trap and euthanize. Trap-neuter-release was approximately twice as expensive to implement as a trap and euthanize program. Results of sensitivity analyses suggested trap-neuter-release programs that employ volunteers are still less cost-effective than trap and euthanize programs that employ paid professionals and that trap-neuter-release was only effective when the total number of colony cats in an area was below 1000. Reducing the rate of abandonment of domestic cats appears to be a more effective solution for reducing the abundance of feral cats.

  11. Evaluation of the susceptibility artifacts and tissue injury caused by implanted microchips in dogs on 1.5 T magnetic resonance imaging.

    PubMed

    Saito, Miyoko; Ono, Shin; Kayanuma, Hideki; Honnami, Muneki; Muto, Makoto; Une, Yumi

    2010-05-01

    Performing magnetic resonance imaging (MRI) in patients with a metallic implant raises concern over the potential complications, including susceptibility artifacts, implant migration, and heat injury. The purpose of this study was to investigate these complications in dogs with implanted microchips by evaluating MR images and the histopathological changes after 1.5 Tesla (T) MRI. Five dogs underwent microchip implantation in the cervicothoracic area. One month later, the area was imaged using 1.5T MRI in three dogs. The microchips were removed surgically together with the surrounding tissue in all dogs. There was significant signal loss and image distortion over a wide range around the area where the microchip was implanted. This change was consistent with susceptibility artifacts, which rendered the affected area including the spinal cord undiagnostic. The artifact was more extensive in T2*-weighted images (gradient-echo) and less extensive in proton density-weighted images (fast spin-echo with short echo time). Histopathologically, all microchips were well-encapsulated with granulation tissue, and there were no evidence of migration of microchips. Cell debris and a moderate number of degenerated cells with fibrin were seen in the inner layer of the granulation tissue in each dog that underwent MRI. These changes were very subtle and did not seem to be clinically significant. The results of this study suggest that, in 1.5T MRI, susceptibility artifacts produced by implanted microchips can be marked, although the dogs with implants appeared to be scanned safely.

  12. Superfluid qubit systems with ring shaped optical lattices.

    PubMed

    Amico, Luigi; Aghamalyan, Davit; Auksztol, Filip; Crepaz, Herbert; Dumke, Rainer; Kwek, Leong Chuan

    2014-03-06

    We study an experimentally feasible qubit system employing neutral atomic currents. Our system is based on bosonic cold atoms trapped in ring-shaped optical lattice potentials. The lattice makes the system strictly one dimensional and it provides the infrastructure to realize a tunable ring-ring interaction. Our implementation combines the low decoherence rates of neutral cold atoms systems, overcoming single site addressing, with the robustness of topologically protected solid state Josephson flux qubits. Characteristic fluctuations in the magnetic fields affecting Josephson junction based flux qubits are expected to be minimized employing neutral atoms as flux carriers. By breaking the Galilean invariance we demonstrate how atomic currents through the lattice provide an implementation of a qubit. This is realized either by artificially creating a phase slip in a single ring, or by tunnel coupling of two homogeneous ring lattices. The single qubit infrastructure is experimentally investigated with tailored optical potentials. Indeed, we have experimentally realized scaled ring-lattice potentials that could host, in principle, n ~ 10 of such ring-qubits, arranged in a stack configuration, along the laser beam propagation axis. An experimentally viable scheme of the two-ring-qubit is discussed, as well. Based on our analysis, we provide protocols to initialize, address, and read-out the qubit.

  13. Experimental observation of the collision of three vortex rings

    NASA Astrophysics Data System (ADS)

    Hernández, R. H.; Monsalve, E.

    2015-06-01

    We investigate for the first time the motion, interaction and simultaneous collision between three initially stable vortex rings arranged symmetrically, making an angle of 120 degrees between their straight path lines. We report results with laminar vortex rings in air and water obtained through measurements of the ring velocity field with a hot-wire anemometer, both in free flight and during the entire collision. In the air experiment, our flow visualizations allowed us to identify two main collision stages. A first ring-dominated stage where the rings slowdown progressively, increasing their diameter rapidly, followed by secondary vortex structures resulting after the rings make contact. Local portions of the vortex tubes of opposite circulation are coupled together thus creating local arm-like vortex structures moving radially in outward directions, rapidly dissipating kinetic energy. From a similar water experiment, we provide detailed shadowgraph visualizations of both the ring bubble and the full size collision, showing clearly the final expanding vortex structure. It is accurately resolved that the physical contact between vortex ring tubes gives rise to three symmetric expanding vortex arms but also the vortex reconnection of the top and lower vortex tubes. The central collision zone was found to have the lowest kinetic energy during the entire collision and therefore it can be identified as a safe zone. The preserved collision symmetries leading to the weak kinematic activity in the safe zone is the first step into the development of an intermittent hydrodynamic trap for small and lightweight particles.

  14. Superfluid qubit systems with ring shaped optical lattices

    PubMed Central

    Amico, Luigi; Aghamalyan, Davit; Auksztol, Filip; Crepaz, Herbert; Dumke, Rainer; Kwek, Leong Chuan

    2014-01-01

    We study an experimentally feasible qubit system employing neutral atomic currents. Our system is based on bosonic cold atoms trapped in ring-shaped optical lattice potentials. The lattice makes the system strictly one dimensional and it provides the infrastructure to realize a tunable ring-ring interaction. Our implementation combines the low decoherence rates of neutral cold atoms systems, overcoming single site addressing, with the robustness of topologically protected solid state Josephson flux qubits. Characteristic fluctuations in the magnetic fields affecting Josephson junction based flux qubits are expected to be minimized employing neutral atoms as flux carriers. By breaking the Galilean invariance we demonstrate how atomic currents through the lattice provide an implementation of a qubit. This is realized either by artificially creating a phase slip in a single ring, or by tunnel coupling of two homogeneous ring lattices. The single qubit infrastructure is experimentally investigated with tailored optical potentials. Indeed, we have experimentally realized scaled ring-lattice potentials that could host, in principle, n ~ 10 of such ring-qubits, arranged in a stack configuration, along the laser beam propagation axis. An experimentally viable scheme of the two-ring-qubit is discussed, as well. Based on our analysis, we provide protocols to initialize, address, and read-out the qubit. PMID:24599096

  15. Calibration of optical traps by dual trapping of one bead.

    PubMed

    Dutov, Pavel; Schieber, Jay

    2013-11-15

    We introduce a method for optical trap calibration that is suitable for viscoelastic material. The method is designed for use on experimental setups with two optical tweezers and is based on pulling a trapped particle with one trap while holding it with the other. No piezo stage is needed, and only one optical trap must be movable with galvo mirrors, piezo mirrors, or acousto-optical deflectors. The method combines advantages of commonly known PSD-fitting and fast-sweeping methods, allowing calibration of a completely fixed trap in a fluid of unknown viscosity/viscoelasticity. A detailed method description, a theoretical derivation, and an experimental comparison to other methods are reported.

  16. Liquid trap seals thermocouple leads

    NASA Technical Reports Server (NTRS)

    Ruppe, E. P.

    1966-01-01

    Liquid trap seals thermocouple leads coming out of a brazing retort that operates with a controlled atmosphere so that air cannot enter the retort and hydrogen cannot escape. The trap is fastened to a duct welded to the retort. Thermocouple leads are led out through the duct and trap, with the fluid forming a gastight seal between the atmosphere and the retort.

  17. Synthesis of cold antihyrogen in a cusp trap

    NASA Astrophysics Data System (ADS)

    Yamazaki, Yasunori

    2011-05-01

    We report here the first successful synthesis of cold antihydrogen atoms employing a cusp trap, which is not to trap but to extract an intensified antihydrogen beam in a field-free region for high precision microwave spectroscopy. This success opens a new path to make a stringent test of the CPT symmetry via observation of ground-state hyperfine transitions of antihydrogen atoms. The cusp trap consists of superconducting anti-Helmholtz coils and a stack of multiple ring electrodes, which provides non-uniform but axially symmetric magnetic and electric fields. Because of this axial symmetry, a large number of antiprotons and positrons are stably stored in the trap. At the same time, antihydrogen atoms in low-field-seeking states synthesized in the cusp trap can be selectively and effectively extracted along the trap axis. Grant-in-Aid for Specially Promoted Research (19002004) of MEXT, Japan, Special Research Projects for Basic Science of RIKEN, Universita di Breascia and Instituto di Fisica Nucleare, Italy.

  18. Search for Optical Binding with Shape Phase Holographic Optical Trapping

    NASA Astrophysics Data System (ADS)

    Roichman, Yohai; Polin, Marco; Cholis, Ilias; Grier, David

    2007-03-01

    Light scattered by an illuminated particle should repel that particle's neighbors through radiation pressure. Nearly two decades ago, Burns, Fournier and Golovchenko (BFG) proposed that the coherent superposition of scattered fields can lead to an attractive interparticle interaction, which they called optical binding. Their pioneering experimental observation has generated considerable interest, most of which has focused on developing the theory for the effect. Accurate measurements of the optical binding force in the BFG geometry have been lacking, however. The need to quantify optical binding forces is particularly acute for colloidal interaction measurements on linear optical traps. We present a new method to directly measure optical binding forces between colloidal spheres that exploits the ability of shape-phase holography to create linear optical traps with accurately specified intensity and phase profiles. Our ability to control the trap's phase profile makes possible precise discrimination between intensity- and field-dependent interactions, i.e. between radiation pressure and optical binding. The same novel technique that allows us to project holographic line traps also can be used to project two- and three-dimensionally structured ring traps, novel Bessel-beam traps, which we also will describe.

  19. The Enceladus Ring

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] The Enceladus Ring (labeled)

    This excellent view of the faint E ring -- a ring feature now known to be created by Enceladus -- also shows two of Saturn's small moons that orbit within the ring, among a field of stars in the background.

    The E ring extends from three to eight Saturn radii -- about 180,000 kilometers (118,000 miles) to 482,000 kilometers (300,000 miles). Its full extent is not visible in this view.

    Calypso (22 kilometers, or 14 miles across) and Helene (32 kilometers, or 20 miles across) orbit within the E ring's expanse. Helene skirts the outer parts of the E ring, but here it is projected in front of a region deeper within the ring.

    Calypso and Helene are trojan satellites, or moons that orbit 60 degrees in front or behind a larger moon. Calypso is a Tethys trojan and Helene is a trojan of Dione.

    An interesting feature of note in this image is the double-banded appearance of the E-ring, which is created because the ring is somewhat fainter in the ringplane than it is 500-1,000 kilometers (300-600 miles) above and below the ringplane. This appearance implies that the particles in this part of the ring have nonzero inclinations (a similar affect is seen in Jupiter's gossamer ring). An object with a nonzero inclination does not orbit exactly at Saturn's ringplane. Instead, its orbit takes it above and below the ringplane. Scientists are not entirely sure why the particles should have such inclinations, but they are fairly certain that the reason involves Enceladus.

    One possible explanation is that all the E ring particles come from the plume of icy material that is shooting due south out of the moon's pole. This means all of the particles are created with a certain velocity out of the ringplane, and then they orbit above and below that plane.

    Another possible explanation is that Enceladus produces particles with a range of speeds, but the moon gravitationally

  20. Radial cold trap

    DOEpatents

    Grundy, Brian R.

    1981-01-01

    The radial cold trap comprises a housing having a plurality of mesh bands disposed therein. The mesh bands comprise concentrically arranged bands of mesh with the mesh specific surface area of each band increasing from the outermost mesh band to the innermost mesh band. An inlet nozzle is attached to the outside section of the housing while an outlet nozzle is attached to the inner portion of the housing so as to be concentrically connected to the innermost mesh band. An inlet baffle having orifices therein may be disposed around the outermost mesh band and within the housing for directing the flow of the fluid from the inlet nozzle to the outermost mesh band in a uniform manner. The flow of fluid passes through each consecutive mesh band and into the outlet nozzle. The circular pattern of the symmetrically arranged mesh packing allows for better utilization of the entire cold trap volume.

  1. Radial cold trap

    DOEpatents

    Grundy, B.R.

    1981-09-29

    The radial cold trap comprises a housing having a plurality of mesh bands disposed therein. The mesh bands comprise concentrically arranged bands of mesh with the mesh specific surface area of each band increasing from the outermost mesh band to the innermost mesh band. An inlet nozzle is attached to the outside section of the housing while an outlet nozzle is attached to the inner portion of the housing so as to be concentrically connected to the innermost mesh band. An inlet baffle having orifices therein may be disposed around the outermost mesh band and within the housing for directing the flow of the fluid from the inlet nozzle to the outermost mesh band in a uniform manner. The flow of fluid passes through each consecutive mesh band and into the outlet nozzle. The circular pattern of the symmetrically arranged mesh packing allows for better utilization of the entire cold trap volume. 2 figs.

  2. Ion Trap Quantum Computing

    DTIC Science & Technology

    2011-12-01

    an inspiring speech at the MIT Physics of Computation 1st Conference in 1981, Feynman proposed the development of a computer that would obey the...on ion trap based 36 quantum computing for physics and computer science students would include lecture notes, slides, lesson plans, a syllabus...reading lists, videos, demonstrations, and laboratories. 37 LIST OF REFERENCES [1] R. P. Feynman , “Simulating physics with computers,” Int. J

  3. Filter vapor trap

    DOEpatents

    Guon, Jerold

    1976-04-13

    A sintered filter trap is adapted for insertion in a gas stream of sodium vapor to condense and deposit sodium thereon. The filter is heated and operated above the melting temperature of sodium, resulting in a more efficient means to remove sodium particulates from the effluent inert gas emanating from the surface of a liquid sodium pool. Preferably the filter leaves are precoated with a natrophobic coating such as tetracosane.

  4. Acoustic trapping for bacteria identification in positive blood cultures with MALDI-TOF MS.

    PubMed

    Hammarström, Björn; Nilson, Bo; Laurell, Thomas; Nilsson, Johan; Ekström, Simon

    2014-11-04

    Matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is currently changing the clinical routine for identification of microbial pathogens. One important application is the rapid identification of bacteria for the diagnosis of bloodstream infections (BSI). A novel approach based on acoustic trapping and an integrated selective enrichment target (ISET) microchip that improves the sample preparation step for this type of analysis is presented. The method is evaluated on clinically relevant samples in the form of Escherichia coli infected blood cultures. It is shown that noncontact acoustic trapping enables capture, enrichment, and washing of bacteria directly from the complex background of crude blood cultures. The technology replaces centrifugation-based separation with a faster and highly automated sample preparation method that minimizes manual handling of hazardous pathogens. The presented method includes a solid phase extraction step that was optimized for enrichment of the bacterial proteins and peptides that are used for bacterial identification. The acoustic trapping-based assay provided correct identification in 12 out 12 cases of E. coli positive blood cultures with an average score of 2.19 ± 0.09 compared to 1.98 ± 0.08 when using the standard assay. This new technology opens up the possibility to automate and speed up an important and widely used diagnostic assay for bloodstream infections.

  5. Earth: A Ringed Planet?

    NASA Astrophysics Data System (ADS)

    Hancock, L. O.; Povenmire, H.

    2010-12-01

    Among the most beautiful findings of the Space Age have been the discoveries of planetary rings. Not only Saturn but also Jupiter, Uranus and Neptune have rings; Saturn’s ring system has structures newly discovered; even Saturn's moon Rhea itself has a ring. All these are apparently supplied by material from the planetary moons (Rhea's ring by Rhea itself). The question naturally arises, why should the Earth not have a ring, and on the other hand, if it does, why has it not been observed? No rings have yet been observed in the inner solar system, but after all, rings in the inner solar system might simply tend to be fainter and more transient than those of the outer solar system: the inner solar system is more affected by the solar wind, and the Sun’s perturbing gravitational influence is greater. J.A. O’Keefe first suggested (1980) that Earth might have a ring system of its own. An Earth ring could account for some climate events. O’Keefe remarked that formation or thickening of a ring system in Earth’s equatorial plane could drive glaciation by deepening the chill of the winter hemisphere. (It is very well established that volcanic dust is an effective agent for the extinction of sunlight; this factor can be overwhelmingly apparent in eclipse observations.) O’Keefe died in 2000 and the speculation was not pursued, but the idea of an Earth ring has a prima facie reasonableness that calls for its renewed consideration. The program of this note is to hypothesize that, as O’Keefe proposed: (a) an Earth ring system exists; (b) it affects Earth's weather and climate; (c) the tektite strewn fields comprise filaments of the ring fallen to Earth's surface on various occasions of disturbance by comets or asteroids. On this basis, and drawing on the world's weather records, together with the Twentieth Century Reanalysis by NCEP/CIRES covering the period 1870-2010 and the geology of the tektite strewn fields, we herein propose the hypothesized Earth ring

  6. Seal ring installation tool

    NASA Technical Reports Server (NTRS)

    Haselmaier, L. Haynes (Inventor)

    2004-01-01

    A seal ring tool that allows an installer to position a primary seal ring between hub ends of pipe flanges that are being assembled together. The tool includes a pivoting handle member and extension arms attached to the pivoting handle member. The ends of the arms have side indentation type longitudinal grooves angled toward one another for holding the primary seal ring in place between the hubs of respective pipes that are to be attached together. The arms of the tool can also have flat sides that can be used to abut against an optional second larger seal that is supported within a groove in one of the hub ends so that the second hub end can then be moved against the other side of the primary seal ring. Once the seal ring is positioned between the pipe hubs, the pipe hubs can be moved about the seal ring due to the flat sides of the arms of the tool. The tool eliminates the chances of damaging and contaminating seal rings being installed within pipe hubs that are being attached to one another.

  7. Design and operation of a portable scanner for high performance microchip capillary array electrophoresis.

    PubMed

    Scherer, James R; Liu, Peng; Mathies, Richard A

    2010-11-01

    We have developed a compact, laser-induced fluorescence detection scanner, the multichannel capillary array electrophoresis portable scanner (McCAEPs) as a platform for electrophoretic detection and control of high-throughput, integrated microfluidic devices for genetic and other analyses. The instrument contains a confocal optical system with a rotary objective for detecting four different fluorescence signals, a pneumatic system consisting of two pressure/vacuum pumps and 28 individual addressable solenoid valves for control of on-chip microvalves and micropumps, four Polymerase Chain Reaction (PCR) temperature control systems, and four high voltage power supplies for electrophoresis. The detection limit of the instrument is ~20 pM for on-chip capillary electrophoresis of fluorescein dyes. To demonstrate the system performance for forensic short tandem repeat (STR) analysis, two experiments were conducted: (i) electrophoretic separation and detection of STR samples on a 96-lane microfabricated capillary array electrophoresis microchip. Fully resolved PowerPlex(®) 16 STR profiles amplified from 1 ng of 9947A female standard DNA were successfully obtained; (ii) nine-plex STR amplification, sample injection, separation, and fluorescence detection of 100-copy 9948 male standard DNA in a single integrated PCR- capillary electrophoresis microchip. These results demonstrate that the McCAEPs can be used as a versatile control and detection instrument that operates integrated microfluidic devices for high-performance forensic human identification.

  8. In-channel amperometric detection for microchip electrophoresis using a wireless isolated potentiostat

    PubMed Central

    Gunasekara, Dulan B.; Hulvey, Matthew K.; Lunte, Susan M.

    2012-01-01

    The combination of microchip electrophoresis (ME) with amperometric detection leads to a number of analytical challenges that are associated with isolating the detector from the high voltages used for the separation. While methods such as end-channel alignment and the use of decouplers have been employed, they have limitations. A less common method has been to utilize an electrically isolated potentiostat. This approach allows placement of the working electrode directly in the separation channel without using a decoupler. This paper explores the use of microchip electrophoresis and electrochemical detection (ME-EC) with an electrically isolated potentiostat for the separation and in-channel detection of several biologically important anions. The separation employed negative polarity voltages and tetradecyltrimethylammonium bromide (TTAB, as a buffer modifier) for the separation of nitrite (NO2-), glutathione (GSH), ascorbic acid (AA), and tyrosine (Tyr). A half-wave potential (E½) shift of approximately negative 500 mV was observed for NO2- and H2O2 standards in the in-channel configuration compared to end channel. Higher separation efficiencies were observed for both NO2- and H2O2 with the in-channel detection configuration. The limits of detection were approximately two-fold lower and the sensitivity was approximately two-fold higher for in-channel detection of nitrite when compared to end-channel. The application of this microfluidic device for the separation and detection of biomarkers related to oxidative stress is described. PMID:21437918

  9. Application of Microchip Fabricated of Photosensitive Glass for Thermal Lens Microscopy

    NASA Astrophysics Data System (ADS)

    Ito, Takeshi; Uchiyama, Kenji; Ohya, Seishiro; Kitamori, Takehiko

    2001-09-01

    Conventional wet chemical processes have not been successful in achieving a high aspect ratio channel on glass wafers because of isotropic etching of glass by hydrogen fluoride (HF). We fabricated a microchip of photosensitive glass in order to obtain a high aspect ratio channel (width:depth:aspect ratio = 150 μm:250 μm:1.67). The water glass bonding technique was applied to bond glass wafers at low temperature (40-80°C). The results of studying the characteristics of the water glass bonding technique for the micro total analysis system (μ-TAS) use show that dissolution of the material (sodium) from water glass layer was avoided by placing it in deionized water at 60°C for 4 h, and the bond strength was weakened by keeping it at high pH for a day. The microchip was available to analyze the amount of nitrite acid present by thermal lens microscopy as one method of optical chemical analysis. Although the etched glass surface had a roughness of about 1 μm, the calibration curve of thermal lens microscopy was similar to that of spectrophotometry.

  10. Low-power microwave-mediated heating for microchip-based PCR.

    PubMed

    Marchiarullo, Daniel J; Sklavounos, Angelique H; Oh, Kyudam; Poe, Brian L; Barker, N Scott; Landers, James P

    2013-09-07

    Microwave energy has been used to rapidly heat food and drinks for decades, in addition to assisting other chemical reactions. However, only recently has microwave energy been applied in microfluidic systems to heat solution in reaction chambers, in particular, the polymerase chain reaction (PCR). One of the difficulties in developing microwave-mediated heating on a microchip is the construction of the appropriate architecture for delivery of the energy to specific micro-areas on the microchip. This work employs commercially-available microwave components commonly used in the wireless communications industry to generate a microwave signal, and a microstrip transmission line to deliver the energy to a 1 μL reaction chamber fabricated in plastic microdevices. A model was developed to create transmission lines that would optimally transmit energy to the reaction chamber at a given frequency, minimizing energy usage while focusing microwave delivery to the target chamber. Two different temperature control methods were demonstrated, varying microwave power or frequency. This system was used to amplify a fragment of the lambda-phage genome, thereby demonstrating its potential for integration into a portable PCR system.

  11. Design and performance of a microchip electrophoresis instrument with sensitive variable-wavelength fluorescence detection.

    PubMed

    Belder, Detlev; Deege, Alfred; Maass, Martin; Ludwig, Martin

    2002-07-01

    A modular instrument for high-speed microchip electrophoresis (MCE) equipped with a sensitive variable-wavelength fluorescence detection system was developed and evaluated. The experimental setup consists mainly of a lamp-based epifluorescence microscope for variable-wavelength fluorescence detection and imaging and a programmable four-channel bipolar high-voltage source capable of delivering up to +/- 10 kV per channel. The optical unit was equipped with a high-sensitivity photomultiplier tube and an adjustable aperture. The system was applied to MCE separations of flurescein isothiocyanate (FITC)-labelled amines utilizing blue light (450-480 nm) for excitation as well as for the separation of rhodamines utilizing excitation light in the green spectral region (531-560 nm). At optimized conditions baseline separation of four FITC-labelled amines could be obtained in less than 50 s at a detection limit of 460 ppt (1 nM) with a signal-to-noise ratio of 3:1. Three rhodamines could be baseline-separated in less than 6 s at a detection limit of 240 ppt (500 pM). The relative standard deviations of absolute migration times determined in repetitive MCE separations of FITC-labelled amines were below 2.5% (n= 25). By the application of cyclodextrin-modified electrolytes, chiral separation of FITC-labelled amines could be performed in seconds demonstrating the potential of microchip electrophoresis for chiral high-throughput screening.

  12. Poly(vinyl alcohol)-coated microfluidic devices for high-performance microchip electrophoresis.

    PubMed

    Belder, Detlev; Deege, Alfred; Kohler, Frank; Ludwig, Martin

    2002-10-01

    The channels of microfluidic glass chips have been coated with poly(vinyl alcohol) (PVA). Applied for microchip electrophoresis, the coated devices exhibited a suppressed electroosmotic flow and improved separation performance. The superior performance of PVA-coated channels could be demonstrated by electrophoretic separations of labeled amines and by video microscopy. While a distorted sample zone is injected using uncoated channels the application of PVA-coated channels results in an improved shape of the sample zone with less band broadening. Applying PVA-coated microchips for the separation of amines labeled with Alexa Fluor 350 even sub-second separations, utilizing a separation length of only 650 microm, could be obtained, while this was not possible using uncoated devices. By using PVA-coated devices rather than an uncoated chip a threefold increase in separation efficiencies could be observed. As the electroosmotic flow (EOF) was suppressed, the anionic compounds were detected at the anode whereas the dominant EOF in uncoated devices resulted in an effective mobility to the cathode. Besides improved separation performance another important feature of the PVA-coated channels was the suppressed adsorption of fluorescent compounds in repetitive runs which results in an improved robustness and detection sensitivity. Applying PVA-coated channels, rinsing or etching steps could be omitted while this was necessary for a reliable operation of uncoated devices.

  13. High-speed chiral separations on a microchip with UV detection.

    PubMed

    Ludwig, Martin; Kohler, Frank; Belder, Detlev

    2003-09-01

    Fast chiral separations of a variety of basic and acidic compounds could be realized on microfluidic quartz chips. A microchip electrophoresis instrument equipped with a linear imaging UV-detector was used. The usually applied but troublesome fluorescence tagging in order to enable fluorescence detection could be omitted. Using sulfated cyclodextrins as chiral selectors baseline separation of 19 compounds could be achieved in less than 1 min with high reproducibility. The relative standard deviation of migration time was below 7%. The fastest separation could be performed in 2.5 s which is to date the fastest separation of enantiomers reported. It was possible to apply microchip electrophoresis (MCE) for the determination of high enantiomeric excess (ee) values, as exemplarily shown for pseudoephedrin where 2% of the minor enantiomer could reliably be determined beside high amount of the other isomer. Successful separation of a mixture of 3 chiral drugs could be performed in a single run in less than 11 s utilizing a separation length of only 12 mm. These results show that MCE has great potential for fast chiral analysis and high-throughput screening.

  14. Determination of heavy metal ions by microchip capillary electrophoresis coupled with contactless conductivity detection.

    PubMed

    Liu, Benyan; Zhang, Yi; Mayer, Dirk; Krause, Hans-Joachim; Jin, Qinghui; Zhao, Jianlong; Offenhäusser, Andreas; Xu, Yuansen

    2012-04-01

    An integrated detection circuitry based on a lock-in amplifier was designed for contactless conductivity determination of heavy metals. Combined with a simple-structure electrophoresis microchip, the detection system is successfully utilized for the separation and determination of various heavy metals. The influences of the running buffer and detection conditions on the response of the detector have been investigated. Six millimole 2-morpholinoethanesulfonic acid + histidine were selected as buffer for its stable baseline and high sensitivity. The best signals were recorded with a frequency of 38 kHz and 20 V(pp). The results showed that Mn(2+), Cd(2+), Co(2+), and Cu(2+) can be successfully separated and detected within 100 s by our system. The detection limits for five heavy metals (Mn(2+), Pb(2+), Cd(2+), Co(2+), and Cu(2+)) were determined to range from about 0.7 to 5.4 μM. This microchip system performs a crucial step toward the realization of a simple, inexpensive, and portable analytical device for metal analysis.

  15. Temperature-dependent spectroscopy and microchip laser operation of Nd:KGd(WO4)2

    NASA Astrophysics Data System (ADS)

    Loiko, P.; Yoon, S. J.; Serres, J. M.; Mateos, X.; Beecher, S. J.; Birch, R. B.; Savitski, V. G.; Kemp, A. J.; Yumashev, K.; Griebner, U.; Petrov, V.; Aguiló, M.; Díaz, F.; Mackenzie, J. I.

    2016-08-01

    High-resolution absorption and stimulated-emission cross-section spectra are presented for monoclinic Nd:KGd(WO4)2 (Nd:KGW) laser crystals in the temperature range 77-450 K. At room-temperature, the maximum stimulated emission cross-section is σSE = 21.4 × 10-20 cm2 at 1067.3 nm, for light polarization E || Nm. The lifetime of the 4F3/2 state of Nd3+ in KGW is practically temperature independent at 115 ± 5 μs. Measurement of the energy transfer upconversion parameter for a 3 at.% Nd:KGW crystal proved that this was significantly smaller than for alternative hosts, ∼2.5 × 10-17 cm3/s. When cut along the Ng optical indicatrix axis, the Nd:KGW crystal was configured as a microchip laser, generating ∼4 W of continuous-wave output at 1067 nm with a slope efficiency of 61% under diode-pumping. Using a highly-doped (10 at.%) Nd:KGW crystal, the slope efficiency reached 71% and 74% when pumped with a laser diode and a Ti:Sapphire laser, respectively. The concept of an ultrathin (250 μm) Nd:KGW microchip laser sandwiched between two synthetic diamond heat-spreaders is demonstrated.

  16. Neutral polymers as coatings for high resolution electrophoretic separation of Aβ peptides on glass microchips.

    PubMed

    Mesbah, Kiarach; Verpillot, Romain; Chiari, Marcella; Pallandre, Antoine; Taverna, Myriam

    2014-12-21

    This study reports a comparison of the performances of two neutral polymers, poly ethylene-oxide (PEO) and poly(dimethylacrylamide-co-allyl glycidyl ether) (EpDMA), in glass microchips to achieve zone electrophoresis separation of several truncated forms of beta amyloid (Aβ) peptides, sharing very similar structures. The peptides were derivatized by FluoProbes 488 NHS to allow their fluorescence detection. Two protocols based either on PEO or EpDMA led to good pH stabilities in addition to a significant reduction of the electroosmotic flow. These two polymer coatings allowed repeatable analyses and high resolution for the simultaneous analysis of three Aβ peptides, Aβ 1-38, Aβ 1-40 and Aβ 1-42, considered as potential biomarkers of Alzheimer's disease. A recovery study showed that EpDMA was superior in reducing the adsorption of the Aβ peptides on the coated inner wall. Finally, the separation method relying on the EpDMA coated microchips was validated as linear using a calibration curve and the LOD was estimated to be close to 200 nM. Despite very short migration distances, different N-terminal or C-terminal truncated Aβ peptides, corresponding to promising biomarker combinations for the future diagnostic, were fully resolved. The method was successfully applied to detect these peptides in spiked cerebrospinal fluid and has provided a first achievement towards the development of a microsystem that would integrate preconcentration and separation steps.

  17. Microchips and their Significance in Isolation of Circulating Tumor Cells and Monitoring of Cancers.

    PubMed

    Sahmani, Mehdi; Vatanmakanian, Mousa; Goudarzi, Mehdi; Mobarra, Naser; Azad, Mehdi

    2016-01-01

    In micro-fluid systems, fluids are injected into extremely narrow polymer channels in small amounts such as micro-, nano-, or pico-liter scales. These channels themselves are embedded on tiny chips. Various specialized structures in the chips including pumps, valves, and channels allow the chips to accept different types of fluids to be entered the channel and along with flowing through the channels, exert their effects in the framework of different reactions. The chips are generally crystal, silicon, or elastomer in texture. These highly organized structures are equipped with discharging channels through which products as well as wastes of the reactions are secreted out. A particular advantage regarding the use of fluids in micro-scales over macro-scales lies in the fact that these fluids are much better processed in the chips when they applied as micro-scales. When the laboratory is miniaturized as a microchip and solutions are injected on a micro-scale, this combination makes a specialized construction referred to as "lab-on-chip". Taken together, micro-fluids are among the novel technologies which further than declining the costs; enhancing the test repeatability, sensitivity, accuracy, and speed; are emerged as widespread technology in laboratory diagnosis. They can be utilized for monitoring a wide spectrum of biological disorders including different types of cancers. When these microchips are used for cancer monitoring, circulatory tumor cells play a fundamental role.

  18. Rapid Real-Time Antimicrobial Susceptibility Testing with Electrical Sensing on Plastic Microchips with Printed Electrodes.

    PubMed

    Safavieh, Mohammadali; Pandya, Hardik J; Venkataraman, Maanasa; Thirumalaraju, Prudhvi; Kanakasabapathy, Manoj Kumar; Singh, Anupriya; Prabhakar, Devbalaji; Chug, Manjyot Kaur; Shafiee, Hadi

    2017-03-30

    Rapid antimicrobial susceptibility testing is important for efficient and timely therapeutic decision making. Due to globally spread bacterial resistance, the efficacy of antibiotics is increasingly being impeded. Conventional antibiotic tests rely on bacterial culture, which is time-consuming and can lead to potentially inappropriate antibiotic prescription and up-front broad range of antibiotic use. There is an urgent need to develop point-of-care platform technologies to rapidly detect pathogens, identify the right antibiotics, and monitor mutations to help adjust therapy. Here, we report a biosensor for rapid (<90 min), real time, and label-free bacteria isolation from whole blood and antibiotic susceptibility testing. Target bacteria are captured on flexible plastic-based microchips with printed electrodes using antibodies (30 min), and its electrical response is monitored in the presence and absence of antibiotics over an hour of incubation time. We evaluated the microchip with Escherichia coli and methicillin-resistant Staphylococcus aureus (MRSA) as clinical models with ampicillin, ciprofloxacin, erythromycin, daptomycin, gentamicin, and methicillin antibiotics. The results are compared with the current standard methods, i.e. bacteria viability and conventional antibiogram assays. The technology presented here has the potential to provide precise and rapid bacteria screening and guidance in clinical therapies by identifying the correct antibiotics for pathogens.

  19. Hybrid soft-lithography/laser machined microchips for the parallel generation of droplets.

    PubMed

    Muluneh, M; Issadore, D

    2013-12-21

    Microfluidic chips have been developed to generate droplets and microparticles with control over size, shape, and composition not possible using conventional methods. However, it has remained a challenge to scale-up production for practical applications due to the inherently limited throughput of micro-scale devices. To address this problem, we have developed a self-contained microchip that integrates many (N = 512) micro-scale droplet makers. This 3 × 3 cm(2) PDMS microchip consists of a two-dimensional array of 32 × 16 flow-focusing droplet makers, a network of flow channels that connect them, and only two inputs and one output. The key innovation of this technology is the hybrid use of both soft-lithography and direct laser-micromachining. The microscale resolution of soft lithography is used to fabricate flow-focusing droplet makers that can produce small and precisely defined droplets. Deeply engraved (h ≈ 500 μm) laser-machined channels are utilized to supply each of the droplet makers with its oil phase, aqueous phase, and access to an output channel. The engraved channels' low hydrodynamic resistance ensures that each droplet maker is driven with the same flow rates for highly uniform droplet formation. To demonstrate the utility of this approach, water droplets (d ≈ 80 μm) were generated in hexadecane on both 8 × 1 and 32 × 16 geometries.

  20. A strategy to modulate the electrophoretic behavior in plastic microchips using sodium polystyrene sulfonate.

    PubMed

    Guo, Jinxiu; Chen, Yu; Zhao, Lizhi; Sun, Ping; Li, Hongli; Zhou, Lei; Wang, Xiayan; Pu, Qiaosheng

    2016-12-16

    Plastic microchips have been broadly used as disposable microfluidic devices, but the poorly defined surface properties limit their application. Herein, we proved that an anionic polymer could be used as the background electrolyte (BGE) to provide a strong and stable cathodic electroosmotic flow (EOF) and modulate the electrophoretic behavior for efficient separation in relative thicker microchannels (∼75μm id). A cathodic EOF of ∼3.3×10(-4)cm(2)V(-1)s(-1) was maintained using sodium polystyrene sulfonate (PSSNa) with a molecular weight of 5×10(5) as the BGE, which ensured fluorescein isothiocyanate labeled biogenic amines (BAs) appeared ahead of other components in the electropherograms obtained with microchips of cyclic olefin copolymer. Four selected BAs appeared within 50s and theoretical plate numbers of 8.0×10(5)/m were achieved. The role of PSSNa was evaluated with streaming potential, dynamic light scattering, contact angle and atomic force microscopy. Its functionalities as surface modifier, viscosity regulator and pseudostationary phase were also confirmed. The proposed electrophoretic method was applied in the fast determination of BAs in fish meat samples.

  1. Graft linker immobilization for spatial control of protein immobilization inside fused microchips.

    PubMed

    Shirai, Kentaro; Renberg, Björn; Sato, Kae; Mawatari, Kazuma; Konno, Tomohiro; Ishihara, Kazuhiko; Kitamori, Takehiko

    2009-12-01

    Fused silica glass microchips have several attractive features for lab-on-a-chip applications; they can be machined with excellent precision down to nanospace; are stable; transparent and can be modified with a range of silanization agents to change channel surface properties. For immobilization, however, ligands must be added after bonding, since the harsh bonding conditions using heat or hydrofluoric acid would remove all prior immobilized ligands. For spatial control over immobilization, UV-mediated immobilization offers several advantages; spots can be created in parallel, the feature size can be made small, and spatial control over patterns and positions is excellent. However, UV sensitive groups are often based on hydrophobic chemical moieties, which unfortunately result in greater non-specific binding of biomolecules, especially proteins. Here, we present techniques in which any -CH(x) (x=1,2,3) containing surface coating can be used as foundation for grafting a hydrophilic linker with a chemical anchor, a carboxyl group, to which proteins and amine containing molecules can be covalently coupled. Hence, the attractive features of many well-known protein and biomolecule repelling polymer coatings can be utilized while achieving site-specific immobilization only to pre-determined areas within the bonded microchips.

  2. Error removal in microchip-synthesized DNA using immobilized MutS.

    PubMed

    Wan, Wen; Li, Lulu; Xu, Qianqian; Wang, Zhefan; Yao, Yuan; Wang, Rongliang; Zhang, Jia; Liu, Haiyan; Gao, Xiaolian; Hong, Jiong

    2014-07-01

    The development of economical de novo gene synthesis methods using microchip-synthesized oligonucleotides has been limited by their high error rates. In this study, a low-cost, effective and improved-throughput (up to 32 oligos per run) error-removal method using an immobilized cellulose column containing the mismatch binding protein MutS was produced to generate high-quality DNA from oligos, particularly microchip-synthesized oligonucleotides. Error-containing DNA in the initial material was specifically retained on the MutS-immobilized cellulose column (MICC), and error-depleted DNA in the eluate was collected for downstream gene assembly. Significantly, this method improved a population of synthetic enhanced green fluorescent protein (720 bp) clones from 0.93% to 83.22%, corresponding to a decrease in the error frequency of synthetic gene from 11.44/kb to 0.46/kb. In addition, a parallel multiplex MICC error-removal strategy was also evaluated in assembling 11 genes encoding ∼21 kb of DNA from 893 oligos. The error frequency was reduced by 21.59-fold (from 14.25/kb to 0.66/kb), resulting in a 24.48-fold increase in the percentage of error-free assembled fragments (from 3.23% to 79.07%). Furthermore, the standard MICC error-removal process could be completed within 1.5 h at a cost as low as $0.374 per MICC.

  3. Identification of chemical warfare agents using a portable microchip-based detection device

    NASA Astrophysics Data System (ADS)

    Petkovic-Duran, K.; Swallow, A.; Sexton, B. A.; Glenn, F.; Zhu, Y.

    2011-12-01

    Analysis of chemical warfare agents (CWAs) and their degradation products is an important verification component in support of the Chemical Weapons Convention and urgently demanding rapid and reliable analytical methods. A portable microchip electrophoresis (ME) device with contactless conductivity (CCD) detection was developed for the in situ identification of CWA and their degradation products. A 10mM MES/His, 0.4mM CTAB - based separation electrolyte accomplished the analysis of Sarin (GB), Tabun( GA) and Soman (GD) in less than 1 min, which is the fastest screening of nerve agents achieved with portable ME and CCD based detection methods to date. Reproducibility of detection was successfully demonstrated on simultaneous detection of GB (200ppm) and GA (278ppm). Reasonable agreement for the four consecutive runs was achieved with the mean peak time for Sarin of 29.15s, and the standard error of 0.58s or 2%. GD and GA were simultaneously detected with their degradation products methylphosphonic acid (MPA), pinacolyl methylphosphonic acid (PMPA) and O-Ethyl Phosphorocyanidate (GAHP and GAHP1) respectively. The detection limit for Sarin was around 35ppb. To the best of our knowledge this is the best result achieved in microchip electrophoresis and contactless conductivity based detection to date.

  4. A Continuous-Flow Polymerase Chain Reaction Microchip With Regional Velocity Control

    PubMed Central

    Li, Shifeng; Fozdar, David Y.; Ali, Mehnaaz F.; Li, Hao; Shao, Dongbing; Vykoukal, Daynene M.; Vykoukal, Jody; Floriano, Pierre N.; Olsen, Michael; McDevitt, John T.; Gascoyne, Peter R.C.; Chen, Shaochen

    2009-01-01

    This paper presents a continuous-flow polymerase chain reaction (PCR) microchip with a serpentine microchannel of varying width for “regional velocity control.” Varying the channel width by incorporating expanding and contracting conduits made it possible to control DNA sample velocities for the optimization of the exposure times of the sample to each temperature phase while minimizing the transitional periods during temperature transitions. A finite element analysis (FEA) and semi-analytical heat transfer model was used to determine the distances between the three heating assemblies that are responsible for creating the denaturation (96 °C), hybridization (60 °C), and extension (72 °C) temperature zones within the microchip. Predictions from the thermal FEA and semi-analytical model were compared with temperature measurements obtained from an infrared (IR) camera. Flow-field FEAs were also performed to predict the velocity distributions in the regions of the expanding and contracting conduits to study the effects of the microchannel geometry on flow recirculation and bubble nucleation. The flow fields were empirically studied using micro particle image velocimetry (μ-PIV) to validate the flow-field FEA’s and to determine experimental velocities in each of the regions of different width. Successful amplification of a 90 base pair (bp) bacillus anthracis DNA fragment was achieved. PMID:19829760

  5. Microchip-based immunoassays with application of silicon dioxide nanoparticle film.

    PubMed

    Li, Yun; Kang, Qin-Shu; Sun, Guo-Ping; Su, Li-Jin; Zheng, Zhen-Hua; Zhang, Zhen-Feng; Wang, Han-Zhong; He, Zhi-Ke; Huang, Wei-Hua

    2012-06-01

    Highly sensitive detection of proteins offers the possibility of early and rapid diagnosis of various diseases. Microchip-based immunoassay integrates the benefits from both immunoassays (high specificity of target sample) and microfluidics (fast analysis and low sample consumption). However, direct capture of proteins on bare microchannel surface suffers from low sensitivity due to the low capacity of microsystem. In this study, we demonstrated a microchip-based heterogeneous immunoassay using functionalized SiO(2) nanoparticles which were covalently assembled on the surface of microchannels via a liquid-phase deposition technique. The formation of covalent bonds between SiO(2) nanoparticles and polydimethylsiloxane substrate offered sufficient stability of the microfluidic surface, and furthermore, substantially enhanced the protein capturing capability, mainly due to the increased surface-area-to-volume ratio. IgG antigen and FITC-labeled anti-IgG antibody conjugates were adopted to compare protein-enrichment effect, and the fluorescence signals were increased by ~75-fold after introduction of functionalized SiO(2) nanoparticles film. Finally, a proof-of-concept experiment was performed by highly efficient capture and detection of inactivated H1N1 influenza virus using a microfluidic chip comprising highly ordered SiO(2) nanoparticles coated micropillars array. The detection limit of H1N1 virus antigen was 0.5 ng mL(-1), with a linear range from 20 to 1,000 ng mL(-1) and mean coefficient of variance of 4.71%.

  6. On-line Sample Preconcentration Using Field-amplified Stacking Injection in Microchip Capillary Electrophoresis

    PubMed Central

    Gong, Maojun; Wehmeyer, Kenneth R.; Limbach, Patrick A.; Arias, Francisco; Heineman, William R.

    2008-01-01

    Previous reports describing sample stacking on microchip capillary electrophoresis (μCE) have regarded the microchip channels as a closed system and treated the bulk flow as in traditional capillary electrophoresis. This work demonstrates that the flows arising from the cross region should be investigated as an open system. It is shown that the pressure-driven flows into or from the branch channels due to bulk velocity mismatch in the main channel should not be neglected but can be used for liquid transportation in the channels. Based on these concepts, a sample preconcentration scheme was developed in a commercially available glass, single-cross chip for μCE. Similar to field-amplified stacking injection in traditional CE, a low conductivity sample buffer plug was introduced into the separation channel immediately before the negatively charged analyte molecules were injected. The detection sensitivity was improved by 94-, 108- and 160-fold for fluorescein-5-isothiocyanate, fluorescein disodium and 5-carboxyfluorescein, respectively, relative to a traditional pinched injection. The calibration curves for fluorescein and 5-carboxyfluorescein demonstrated good linearity in the concentration range (1 to 60 nM) investigated with acceptable reproducibility of migration time and peak height and area ratios (4 to 5% RSD). This preconcentration scheme will be of particular significance to the practical use of μCE in the emerging miniaturized analytical instrumentation. PMID:16737230

  7. Multi-pulse drug delivery from a resorbable polymeric microchip device

    NASA Astrophysics Data System (ADS)

    Grayson, Amy C. Richards; Choi, Insung S.; Tyler, Betty M.; Wang, Paul P.; Brem, Henry; Cima, Michael J.; Langer, Robert

    2003-11-01

    Controlled-release drug delivery systems have many applications, including treatments for hormone deficiencies and chronic pain. A biodegradable device that could provide multi-dose drug delivery would be advantageous for long-term treatment of conditions requiring pulsatile drug release. In this work, biodegradable polymeric microchips were fabricated that released four pulses of radiolabelled dextran, human growth hormone or heparin in vitro. Heparin that was released over 142 days retained on average 96 +/- 12% of its bioactivity. The microchips were 1.2 cm in diameter, 480-560 μm thick and had 36 reservoirs that could each be filled with a different chemical. The devices were fabricated from poly(L-lactic acid) and had poly(D,L-lactic-co-glycolic acid) membranes of different molecular masses covering the reservoirs. A drug delivery system can be designed with the potential to release pulses of different drugs at intervals after implantation in a patient by using different molecular masses or materials for the membrane.

  8. A Scalable Gene Synthesis Platform Using High-Fidelity DNA Microchips

    PubMed Central

    Kosuri, Sriram; Eroshenko, Nikolai; LeProust, Emily; Super, Michael; Way, Jeffrey; Li, Jin Billy; Church, George M.

    2010-01-01

    Development of cheap, high-throughput, and reliable gene synthesis methods will broadly stimulate progress in biology and biotechnology1. Currently, the reliance on column-synthesized oligonucleotides as a source of DNA limits further cost reductions in gene synthesis2. Oligonucleotides from DNA microchips can reduce costs by at least an order of magnitude3,4,5, yet efforts to scale their use have been largely unsuccessful due to the high error rates and complexity of the oligonucleotide mixtures. Here we use high-fidelity DNA microchips, selective oligonucleotide pool amplification, optimized gene assembly protocols, and enzymatic error correction to develop a highly parallel gene synthesis platform. We tested our platform by assembling 47 genes, including 42 challenging therapeutic antibody sequences, encoding a total of ~35 kilo-basepairs of DNA. These assemblies were performed from a complex background containing 13,000 oligonucleotides encoding ~2.5 megabases of DNA, which is at least 50 times larger than previously published attempts. PMID:21113165

  9. Towards dynamic coating of glass microchip chambers for amplifying DNA via the polymerase chain reaction.

    PubMed

    Giordano, B C; Copeland, E R; Landers, J P

    2001-01-01

    As microchip technology evolves to allow for the integration of more complex processes, particularly the polymerase chain reaction (PCR), it will become necessary to define simple approaches for minimizing the effects of surfaces on the chemistry/processes to be performed. We have explored alternatives to silanization of the glass surface with the use of additives that either dynamically coat or adsorb to the glass surface. Polyethylene glycol, polyvinylpyrrolidone (PVP), and hydroxyethylcellulose (HEC) have been explored as potential dynamic coatings and epoxy (poly)dimethylacrylamide (EPDMA) evaluated as an adsorbed coating. By carrying out analysis of the PCR products generated under different conditions via microchip electrophoresis, we demonstrate that these coating agents adequately passivate the glass surface in a manner that prevents interference with the subsequent PCR process. While several of the agents tested allowed for PCR amplification of DNA in glass, the EPDMA was clearly superior with respect to ease of preparation. However, more efficient PCR (larger mass of amplified product) could be obtained by silanizing the glass surface.

  10. Error removal in microchip-synthesized DNA using immobilized MutS

    PubMed Central

    Wan, Wen; LI, Lulu; Xu, Qianqian; Wang, Zhefan; Yao, Yuan; Wang, Rongliang; Zhang, Jia; Liu, Haiyan; Gao, Xiaolian; Hong, Jiong

    2014-01-01

    The development of economical de novo gene synthesis methods using microchip-synthesized oligonucleotides has been limited by their high error rates. In this study, a low-cost, effective and improved-throughput (up to 32 oligos per run) error-removal method using an immobilized cellulose column containing the mismatch binding protein MutS was produced to generate high-quality DNA from oligos, particularly microchip-synthesized oligonucleotides. Error-containing DNA in the initial material was specifically retained on the MutS-immobilized cellulose column (MICC), and error-depleted DNA in the eluate was collected for downstream gene assembly. Significantly, this method improved a population of synthetic enhanced green fluorescent protein (720 bp) clones from 0.93% to 83.22%, corresponding to a decrease in the error frequency of synthetic gene from 11.44/kb to 0.46/kb. In addition, a parallel multiplex MICC error-removal strategy was also evaluated in assembling 11 genes encoding ∼21 kb of DNA from 893 oligos. The error frequency was reduced by 21.59-fold (from 14.25/kb to 0.66/kb), resulting in a 24.48-fold increase in the percentage of error-free assembled fragments (from 3.23% to 79.07%). Furthermore, the standard MICC error-removal process could be completed within 1.5 h at a cost as low as $0.374 per MICC. PMID:24829454

  11. Characterisation of protein composition and detection of IgA in cervicovaginal fluid by microchip technology.

    PubMed

    Werling, József; Kocsis, Béla; Dean, Diane; Kustos, Ildikó

    2008-06-15

    In this paper the application of microchip electrophoresis to examine the protein profile of cervicovaginal fluid and the detection of IgA heavy and light chains is presented. This method is a fast growing field of technology and ensures high-speed analysis requiring only microliters of sample. Proteins with wide range of molecular masses could be separated within 1 min. Cervicovaginal specimens of healthy women showed a complex protein pattern-containing several peaks in the 15-70 kDa region. sIgA is considered to be an important protein constituent of all mucosal surfaces. Detection of sIgA in cervicovaginal samples was achievable by microchip technology. Under reduced circumstances (induced by mercaptoethanol, a component of the denaturating solution) the disulfide bonds connecting IgA heavy and light chains are broken up and chains can be detected as separate peaks during electrophoresis. In 82.5% of the cases only the light chain of IgA could be detected in the clinical samples. The intact IgA heavy chain could be demonstrated in only 12.5% of the cases. Based on our data some conclusions were provided about the correlation of these patterns with the age of patients, pH of the cervicovaginal fluid, operations performed before sample collection and usage of oral contraceptives.

  12. Microchip electrophoresis with wall-jet electrochemical detector: influence of detection potential upon resolution of solutes.

    PubMed

    Pumera, Martin; Merkoçi, Arben; Alegret, Salvador

    2006-12-01

    This report studies the electrochemical response of wall-jet detector for microchip electrophoresis (microCE). It shows that in wall-jet configuration, the electrochemical detector operates in coulometric mode and that there is an influence of detection potential upon peak width and therefore upon the resolution of solutes. Upon raising the detection potential from +0.3 to +0.9 V, the resolution between model analytes, dopamine and catechol, increases from 0.63 to 2.90. The reasons for this behavior originate in wall-jet detector design and in its typically significant higher detector volume than the volume of injected sample. The conversion efficiency of the wall-jet electrochemical detection cell was found to be 97.4% for dopamine and 98.0% for catechol. The paper brings deeper understanding of operations of wall-jet electrochemical detectors for microchip devices, and it explains previously reported significantly sharper peaks when electrocatalytic electrodes (i.e., palladium and carbon nanotube) were used in microCE-electrochemistry wall-jet detector.

  13. DNA detection on a power-free microchip with laminar flow-assisted dendritic amplification.

    PubMed

    Hosokawa, Kazuo; Sato, Takahiro; Sato, Yasunobu; Maeda, Mizuo

    2010-01-01

    In this paper, we describe DNA detection experiments using our two original technologies, power-free microchip and laminar flow-assisted dendritic amplification (LFDA), which were previously applied to immunoassays. A microchip was fabricated by combining a poly(dimethylsiloxane) (PDMS) part having microchannel patterns and a glass plate modified with probe DNA. We carried out two kinds of experiments: the detection of 21-base biotinylated target DNA and the detection of single-nucleotide polymorphism (SNP) in 56-base unlabeled target DNA by sandwich hybridization with biotinylated probe DNA. For both of the experiments, the necessary solutions were injected into microchannels not by an external power source, but by air dissolution into the PDMS part. After a hybridization reaction, the LFDA was started by injecting FITC-labeled streptavidin and biotinylated anti-streptavidin antibody onto the reaction site. With a detection time of 20 min, the limit of detection (LOD) for the biotinylated target was 2.2 pM, and the LOD for the SNP was 10-30 pM, depending on the SNP type.

  14. Application of microchip-CE electrophoresis to follow the degradation of phenolic acids by aquatic plants.

    PubMed

    Ding, Yongsheng; Garcia, Carlos D

    2006-12-01

    In this paper, we describe the separation and detection of six phenolic acids using an electrophoretic microchip with pulsed amperometric detection (PAD). The selected phenolic acids are particularly important because of their biological activity. The analysis of these compounds is typically performed by chromatography or standard CE coupled with a wide variety of detection modes. However, these methods are slow, labor intensive, involve a multistep solvent extraction, require skilled personnel, or use bulky and expensive instrumentation. In contrast, microchip CE offers the possibility of performing simpler, less expensive, and faster analysis. In addition, integrated devices can be custom-fabricated and incorporated with portable computers to perform on-site analysis. In the present report, the effect of the separation potential, buffer pH and composition, injection time and PAD parameters were studied in an effort to optimize both the separation and detection of these phenolic acids. Using the optimized conditions, the analysis can be performed in less than 3 min, with detection limits ranging from 0.73 microM (0.10 microg/mL) for 4-hydroxyphenylacetic acid to 2.12 microM (0.29 microg/mL) for salicylic acid. In order to demonstrate the capabilities of the device, the degradation of a mixture of these acids by two aquatic plants was followed using the optimized conditions.

  15. Microchip electrophoresis with amperometric detection for a novel determination of phenolic compounds in olive oil.

    PubMed

    Godoy-Caballero, María del Pilar; Acedo-Valenzuela, María Isabel; Galeano-Díaz, Teresa; Costa-García, Agustín; Fernández-Abedul, María Teresa

    2012-11-07

    The relevance of the development of microchip electrophoresis applications in the field of food analysis is considered in this work. A novel method to determine important phenolic compounds in extra virgin olive oil samples using a miniaturized chemical analysis system is presented in this paper. Three interesting phenolic compounds in olive oil and fruit (tyrosol, hydroxytyrosol and oleuropein glucoside) were studied by end-channel amperometric detection using a 100 μm gold wire as working electrode in glass microchip electrophoresis. The electrochemical behavior of these compounds was studied and the medium to carry out their detection was selected (0.1 M aqueous sulfuric acid). The best conditions for the separation were achieved in sodium tetraborate (10% methanol, pH 9.50) with different concentrations for the sample and the running buffer in order to allow the sample stacking phenomenon. The injection was carried out using 600 V for 3 s and the separation voltage was set at 1000 V. The quality of the method was evaluated through its analytical figures of merit and by its performance on real extra virgin olive oil samples. Determination of these compounds was carried out using the standard addition calibration method with good recoveries.

  16. Microchip-based single-cell functional proteomics for biomedical applications.

    PubMed

    Lu, Yao; Yang, Liu; Wei, Wei; Shi, Qihui

    2017-03-29

    Cellular heterogeneity has been widely recognized but only recently have single cell tools become available that allow characterizing heterogeneity at the genomic and proteomic levels. We review the technological advances in microchip-based toolkits for single-cell functional proteomics. Each of these tools has distinct advantages and limitations, and a few have advanced toward being applied to address biological or clinical problems that traditional population-based methods fail to address. High-throughput single-cell proteomic assays generate high-dimensional data sets that contain new information and thus require developing new analytical frameworks to extract new biology. In this review article, we highlight a few biological and clinical applications in which microchip-based single-cell proteomic tools provide unique advantages. The examples include resolving functional heterogeneity and dynamics of immune cells, dissecting cell-cell interaction by creating a well-controlled on-chip microenvironment, capturing high-resolution snapshots of immune system functions in patients for better immunotherapy and elucidating phosphoprotein signaling networks in cancer cells for guiding effective molecularly targeted therapies.

  17. Rapid and sensitive measurements of nitrate ester explosives using microchip electrophoresis with electrochemical detection.

    PubMed

    Piccin, Evandro; Dossi, Nicolò; Cagan, Avi; Carrilho, Emanuel; Wang, Joseph

    2009-03-01

    This article describes an effective microchip protocol based on electrophoretic-separation and electrochemical detection for highly sensitive and rapid measurements of nitrate ester explosives, including ethylene glycol dinitrate (EGDN), pentaerythritol tetranitrate (PETN), propylene glycol dinitrate (PGDN) and glyceryl trinitrate (nitroglycerin, NG). Factors influencing the separation and detection processes were examined and optimized. Under the optimal separation conditions obtained using a 15 mM borate buffer (pH 9.2) containing 20 mM SDS, and applying a separation voltage of 1500 V, the four nitrate ester explosives were separated within less than 3 min. The glassy-carbon amperometric detector (operated at -0.9 V vs. Ag/AgCl) offers convenient cathodic detection down to the picogram level, with detection limits of 0.5 ppm and 0.3 ppm for PGDN and for NG, respectively, along with good repeatability (RSD of 1.8-2.3%; n = 6) and linearity (over the 10-60 ppm range). Such effective microchip operation offers great promise for field screening of nitrate ester explosives and for supporting various counter-terrorism surveillance activities.

  18. [Analysis of genetic determinants of multidrug and extensively drug-resistant Mycobacterium tuberculosis using oligonucleotide microchip].

    PubMed

    Zimenkov, D V; Kulagina, E V; Antonova, O V; Surzhikov, S A; Bespiatykh, Iu A; Shitikov, E A; Il'ina, E N; Mikhaĭlovich, V M; Zasedatelev, A S; Griadunov, D A

    2014-01-01

    Steadily growing resistance of the tuberculosis causative agent towards a broad spectrum of anti-tuberculosis drugs calls for rapid and reliable methods for identifying the genetic determinants responsible for this resistance. In this study, we present a biochip-based method for simultaneous identification of mutations within rpoB gene associated with rifampin resistance, mutations in katG, inhA, ahpC genes responsible for isoniazid resistance, mutations within the regions of gyrA and gyrB genes leading to fluoroquinolones resistance, and mutations in the rrs gene and the eis promoter region associated with the resistance to kanamycin, capreomycin and amikacin. The oligonucleotide microchip, as the core element of this assay, provides simultaneous identification of 99 mutations in the format "one sample--one PCR--one microchip", and it makes it possible to complete analysis of multi-drug-resistant and extensively drug-resistant tuberculosis within a single day. The tests on 63 Mycobacterium tuberculosis clinical isolates with different resistance profiles using the developed approach allows us to reveal the spectrum of drug-resistance associated mutations, and to estimate the significance of the inclusion of extra genetic loci in the determination of M. tuberculosis drug resistance.

  19. Determination of glyphosate and AMPA on polyester-toner electrophoresis microchip with contactless conductivity detection.

    PubMed

    da Silva, Eduardo R; Segato, Thiago P; Coltro, Wendell K T; Lima, Renato S; Carrilho, Emanuel; Mazo, Luiz H

    2013-07-01

    This paper reports a method for rapid, simple, direct, and reproducible determination of glyphosate and its major metabolite aminomethylphosphonic acid (AMPA). The platform described herein uses polyester-toner microchips incorporating capacitively coupled contactless conductivity detection and electrophoresis separation of the analytes. The polyester-toner microchip presented 150 μm-wide and 12 μm-deep microchannels, with injection and separation lengths of 10 and 40 mm long, respectively. The best results were obtained with 320 kHz frequency, 4.5 Vpp excitation voltage, 80 mmol/L CHES/Tris buffer at pH 8.8, injection in -1.0 kV for 7 s, and separation in -1.5 kV. RSD values related to the peak areas for glyphosate and AMPA were 1.5 and 3.3% and 10.1 and 8.6% for intra- and interchip assays, respectively. The detection limits were 45.1 and 70.5 μmol/L, respectively, without any attempt of preconcentration of the analytes. Finally, the method was applied to river water samples in which glyphosate and AMPA (1.0 mmol/L each) were added. The recovery results were 87.4 and 83.7% for glyphosate and AMPA, respectively. The recovery percentages and LOD values obtained here were similar to others reported in the literature.

  20. Silicon-based bridge wire micro-chip initiators for bismuth oxide-aluminum nanothermite

    NASA Astrophysics Data System (ADS)

    Staley, C. S.; Morris, C. J.; Thiruvengadathan, R.; Apperson, S. J.; Gangopadhyay, K.; Gangopadhyay, S.

    2011-11-01

    We present a micro-manufacturing process for fabricating silicon-based bridge wire micro-chip initiators with the capacity to liberate joules of chemical energy at the expense of micro joules of input electrical energy. The micro-chip initiators are assembled with an open material reservoir utilizing a novel 47 °C melting point solder alloy bonding procedure and integrated with a bismuth oxide-aluminum nanothermite energetic composite. The electro-thermal conversion efficiency of the initiators is enhanced by the use of a nanoporous silicon bed which impedes thermal coupling between the bridge wire and bulk silicon substrate while maintaining the structural integrity of the device. Electrical behaviors of the ignition elements are investigated to extract minimum input power and energy requirements of 382.4 mW and 26.51 µJ, respectively, both in the absence and presence of an injected bismuth oxide-aluminum nanothermite composition. Programmed combustion of bismuth oxide-aluminum nanothermite housed within these initiators is demonstrated with a success rate of 100% over a 30 to 80 µJ range of firing energies and ignition response times of less than 2 µs are achieved in the high input power operation regime. The micro-initiators reported here are intended for use in miniaturized actuation technologies.

  1. Design and operation of a portable scanner for high performance microchip capillary array electrophoresis

    NASA Astrophysics Data System (ADS)

    Scherer, James R.; Liu, Peng; Mathies, Richard A.

    2010-11-01

    We have developed a compact, laser-induced fluorescence detection scanner, the multichannel capillary array electrophoresis portable scanner (McCAEPs) as a platform for electrophoretic detection and control of high-throughput, integrated microfluidic devices for genetic and other analyses. The instrument contains a confocal optical system with a rotary objective for detecting four different fluorescence signals, a pneumatic system consisting of two pressure/vacuum pumps and 28 individual addressable solenoid valves for control of on-chip microvalves and micropumps, four Polymerase Chain Reaction (PCR) temperature control systems, and four high voltage power supplies for electrophoresis. The detection limit of the instrument is ˜20 pM for on-chip capillary electrophoresis of fluorescein dyes. To demonstrate the system performance for forensic short tandem repeat (STR) analysis, two experiments were conducted: (i) electrophoretic separation and detection of STR samples on a 96-lane microfabricated capillary array electrophoresis microchip. Fully resolved PowerPlex® 16 STR profiles amplified from 1 ng of 9947A female standard DNA were successfully obtained; (ii) nine-plex STR amplification, sample injection, separation, and fluorescence detection of 100-copy 9948 male standard DNA in a single integrated PCR- capillary electrophoresis microchip. These results demonstrate that the McCAEPs can be used as a versatile control and detection instrument that operates integrated microfluidic devices for high-performance forensic human identification.

  2. Light emitting diode, photodiode-based fluorescence detection system for DNA analysis with microchip electrophoresis.

    PubMed

    Hall, Gordon H; Glerum, D Moira; Backhouse, Christopher J

    2016-02-01

    Electrophoretic separation of fluorescently end-labeled DNA after a PCR serves as a gold standard in genetic diagnostics. Because of their size and cost, instruments for this type of analysis have had limited market uptake, particularly for point-of-care applications. This might be changed through a higher level of system integration and lower instrument costs that can be realized through the use of LEDs for excitation and photodiodes for detection--if they provide sufficient sensitivity. Here, we demonstrate an optimized microchip electrophoresis instrument using polymeric fluidic chips with fluorescence detection of end-labeled DNA with a LOD of 0.15 nM of Alexa Fluor 532. This represents orders of magnitude improvement over previously reported instruments of this type. We demonstrate the system with an electrophoretic separation of two PCR products and their respective primers. We believe that this is the first LED-induced fluorescence microchip electrophoresis system with photodiode-based detection that could be used for standard applications of PCR and electrophoresis.

  3. Integrated hybrid polystyrene-polydimethylsiloxane device for monitoring cellular release with microchip electrophoresis and electrochemical detection

    PubMed Central

    Johnson, Alicia S.; Mehl, Benjamin T.; Martin, R. Scott

    2015-01-01

    In this work, a polystyrene (PS)-polydimethylsiloxane (PDMS) hybrid device was developed to enable the integration of cell culture with analysis by microchip electrophoresis and electrochemical detection. It is shown that this approach combines the fundamental advantages of PDMS devices (the ability to integrate pumps and valves) and PS devices (the ability to permanently embed fluidic tubing and electrodes). The embedded fused-silica capillary enables high temporal resolution measurements from off-chip cell culture dishes and the embedded electrodes provide close to real-time analysis of small molecule neurotransmitters. A novel surface treatment for improved (reversible) adhesion between PS and PDMS is described using a chlorotrimethylsilane stamping method. It is demonstrated that a Pd decoupler is efficient at handling the high current (and cathodic hydrogen production) resulting from use of high ionic strength buffers needed for cellular analysis; thus allowing an electrophoretic separation and in-channel detection. The separation of norepinephrine (NE) and dopamine (DA) in highly conductive biological buffers was optimized using a mixed surfactant system. This PS-PDMS hybrid device integrates multiple processes including continuous sampling from a cell culture dish, on-chip pump and valving technologies, microchip electrophoresis, and electrochemical detection to monitor neurotransmitter release from PC 12 cells. PMID:25663849

  4. In-channel amperometric detection for microchip electrophoresis using a wireless isolated potentiostat.

    PubMed

    Gunasekara, Dulan B; Hulvey, Matthew K; Lunte, Susan M

    2011-04-01

    The combination of microchip electrophoresis with amperometric detection leads to a number of analytical challenges that are associated with isolating the detector from the high voltages used for the separation. While methods such as end-channel alignment and the use of decouplers have been employed, they have limitations. A less common method has been to utilize an electrically isolated potentiostat. This approach allows placement of the working electrode directly in the separation channel without using a decoupler. This paper explores the use of microchip electrophoresis and electrochemical detection with an electrically isolated potentiostat for the separation and in-channel detection of several biologically important anions. The separation employed negative polarity voltages and tetradecyltrimethylammonium bromide (as a buffer modifier) for the separation of nitrite (NO₂⁻), glutathione, ascorbic acid, and tyrosine. A half-wave potential shift of approximately negative 500 mV was observed for NO₂⁻ and H₂O₂ standards in the in-channel configuration compared to end-channel. Higher separation efficiencies were observed for both NO₂⁻ and H₂O₂ with the in-channel detection configuration. The limits of detection were approximately two-fold lower and the sensitivity was approximately two-fold higher for in-channel detection of nitrite when compared to end-channel. The application of this microfluidic device for the separation and detection of biomarkers related to oxidative stress is described.

  5. Utilizing Microchip Capillary Electrophoresis Electrospray Ionization for Hydrogen Exchange Mass Spectrometry

    PubMed Central

    Black, William A.; Stocks, Bradley B.; Mellors, J. Scott; Engen, John R.; Ramsey, J. Michael

    2015-01-01

    Hydrogen exchange (HX) mass spectrometry (MS) of complex mixtures requires a fast, reproducible, and high peak capacity separation prior to MS detection. The current paradigm relies on liquid chromatography (LC) with fast gradients performed at low temperatures to minimize back exchange. Unfortunately, under these conditions, the efficiency of LC is limited due to resistance to mass transfer, reducing the capability to analyze complex samples. Capillary electrophoresis (CE), on the other hand, is not limited by resistance to mass transfer, enabling very rapid separations that are not adversely affected by low temperature. Previously, we have demonstrated an integrated microfluidic device coupling CE with electrospray ionization (ESI) capable of very rapid and high efficiency separations. In this work, we demonstrate the utility of this microchip CE-ESI device for HX MS. High speed CE-ESI of a bovine hemoglobin pepsin digestion was performed in 1 minute with a peak capacity of 62 versus a similar LC separation performed in 7 minutes with peak capacity of 31. A room temperature CE method performed in 1.25 minutes provided similar deuterium retention as an 8.5 minute LC method conducted at 0 °C. Separation of a complex mixture with CE was done with considerably better speed and nearly triple the peak capacity than the equivalent separation by LC. Overall the results indicate the potential utility of microchip CE-ESI for HX MS. PMID:25992468

  6. Peculiarities of RBC aggregation studied by double trap optical tweezers

    NASA Astrophysics Data System (ADS)

    Khokhlova, Maria D.; Lyubin, Evgeny V.; Zhdanov, Alexander G.; Rykova, Sofia Yu.; Krasnova, Tatyana N.; Sokolova, Irina A.; Fedyanin, Andrey A.

    2010-04-01

    Aggregation peculiarities of red blood cells (RBCs) in autologous plasma are studied using double trap optical tweezers technique. The positions of RBCs are controlled with submicrometer accuracy by two optical traps formed by strongly focused laser beams (λ=1064 nm). Quantitative measurements of interaction forces between RBCs in pair aggregates are performed. Depending on the RBCs aggregation force, four different end-points of disaggregation induced by optical trap movement are revealed. Analysis of experimental force dependence on the distance between two RBCs during disaggregation is in a good agreement with the model of ring-shaped interaction surfaces of RBCs in pair aggregate. Aggregation velocities measured are shown to be strongly different for healthy and pathologic (System Lupus Erythematosis - SLE) blood samples.

  7. Specific distribution behavior of a ternary mixture of solvents fed into bent and wound microchannels in microchips.

    PubMed

    Nishiyama, Kei; Murata, Masaharu; Hashimoto, Masahiko; Tsukagoshi, Kazuhiko

    2013-01-01

    The tube radial distribution of ternary solvents (water-hydrophilic/hydrophobic organic mixture) fed into bent and wound microchannels in a microchip was examined by fluorescence observations of dyes dissolved in the solvents under laminar flow conditions. Four kinds of microchips incorporating bent microchannels were used, together with a microchip with a straight channel. The microchannels had different bending times (2, 4, or 12 times), bending radii (0.8, 2.3, or 3 mm), and total channel lengths (80, 120, 200, or 500 mm). A water-acetonitrile (hydrophilic)-ethyl acetate (hydrophobic) mixture containing relatively hydrophilic Eosin Y (green) and hydrophobic perylene (blue) was delivered into the bent microchannels in the microchips. The fluorescence of the green and blue dyes enabled us to observe the specific radial distribution behavior of the ternary solvents in the bent micro channels at 0°C, including liquid-liquid interfaces. Further, the radial distribution pattern of the solvents was clearly observed in the wound microchannel (bending radius, ca. 0.1 mm; real total channel length, 500 mm; and apparent straight channel length, 40 mm) at 20°C (room temperature) as well as 0°C. It was found that the radial distribution behaviors of the solvents were successfully generated in even specific microchannels including various types of curves under the present conditions.

  8. Doping of a dielectric layer as a new alternative for increasing sensitivity of the contactless conductivity detection in microchips.

    PubMed

    Lima, Renato Sousa; Segato, Thiago Pinotti; Gobbi, Angelo Luiz; Coltro, Wendell Karlos Tomazelli; Carrilho, Emanuel

    2011-12-21

    This communication describes a new procedure to increase the sensitivity of C(4)D in PDMS/glass microchips. The method consists in doping the insulating layer (PDMS) over the electrodes with nanoparticles of TiO(2), increasing thus its dielectric constant. The experimental protocol is simple, inexpensive, and fast.

  9. Silver-cemented frit formation for the stabilization of the packing structure in the microchannel of electrochromatographic microchips.

    PubMed

    Park, Jongman; Oh, Hyejin; Jeon, In-Sun

    2011-10-28

    A simple but effective frit formation technique was developed to stabilize the packing structure inside the microchannel of capillary electrochromatographic microchips, utilizing the electroless plating technique. A Ag(NH(3))(2)(+) solution was allowed to diffuse through the colloidal silica packing in the microchannel from the reservoir of the microchip for a limited amount of time, and then it was reduced by an excess amount of formaldehyde solution. A frit structure of ~70 μm in length was formed at the entrance of the microchannel without clogging when treated with 1mM Ag(NH(3))(2)(+) ion and formaldehyde for 30s and 150 s, respectively. The formation of the frit structure was confirmed by a scanning electron microscopy. The stability of the packing structure was tested rigorously and then confirmed by applying alternating electroosmotic flows back and forth with pulsed potential steps on both sides of the frit structure. The effect of the treatment on the electrochromatograms was evaluated after the microchips were repeatedly used and stored for a long period of time. The results indicated that the silver-cemented frit structure extended the lifetime of the fully packed CEC microchips distinctly.

  10. From Bonding Wires to Banding Women. Proceedings of the International Consultation on Micro-Chips Technology (Manila, Philippines, October 1986).

    ERIC Educational Resources Information Center

    Center for Women's Resources, Quezon City (Philippines).

    In October 1986, 40 women from 12 countries gathered in the Philippines for a 10-day meeting of organizers, educators, and workers affected by and confronting the international electronics industry in microchip plants and in automated offices. Participants were from Malaysia, Indonesia, Thailand, the Philippines, Hong Kong, Japan, the Netherlands,…

  11. Coupled-cavity electro-optically {ital Q}-switched Nd:YVO{sub 4} microchip lasers

    SciTech Connect

    Zayhowski, J.J.; Dill, C. III

    1995-04-01

    Nd:YVO{sub 4} microchip lasers have been electro-optically {ital Q} switched to produce 12-{mu}J pulses of 115-ps duration at repetition rates of up to 1 kHz. At a repetition rate of 2.25 MHz, 0.16-{mu}J pulses with an 8.8-ns duration were obtained.

  12. Dynamics of the Uranian Rings

    NASA Technical Reports Server (NTRS)

    Dermott, S. F.

    1984-01-01

    Some of the problems of the shepherding satellite model of Goldreich ant tremaine are discussed. The following topics are studied: (1) optical depths of the all the observed narrow rings; (2) satellite and ring separation timescales; (3) ring edge sharpness; (4) shock formation in narrow rings; (5) the existence of small satellites near the Uranian rings; and (6) the apse and node alignments of the eccentric and inclined rings.

  13. Heavy ion storage rings

    SciTech Connect

    Schuch, R.

    1987-01-01

    A brief overview of synchrotron storage rings for heavy ions, which are presently under construction in different accelerator laboratories is given. Ions ranging from protons up to uranium ions at MeV/nucleon energies will be injected into these rings using multiturn injection from the accelerators available or being built in these laboratories. After injection, it is planned to cool the phase space distribution of the ions by merging them with cold electron beams or laser beams, or by using stochastic cooling. Some atomic physics experiments planned for these rings are presented.

  14. Alternative parallel ring protocols

    NASA Technical Reports Server (NTRS)

    Mukkamala, R.; Foudriat, E. C.; Maly, Kurt J.; Kale, V.

    1990-01-01

    Communication protocols are know to influence the utilization and performance of communication network. The effect of two token ring protocols on a gigabit network with multiple ring structure is investigated. In the first protocol, a mode sends at most one message on receiving a token. In the second protocol, a mode sends all the waiting messages when a token is received. The behavior of these protocols is shown to be highly dependent on the number of rings as well as the load in the network.

  15. Supernumerary small ring chromosome.

    PubMed Central

    Kaffe, S; Kim, H J; Hsu, L Y; Brill, C B; Hirschhorn, K

    1977-01-01

    A supernumerary small ring chromosome was found in 30% of cultured peripheral leucocytes and 50% of skin fibroblasts in a 6-year-old boy with mild mental retardation and midline cleft palate. The extra chromosome appeared to carry a densely staining region on Giemsa banding. The banding patterns of the remaining 46 chromosomes were normal. C banding indicated that the ring chromosome contained mainly centromeric constitutive heterochromatin. Chromosome analysis of both parents showed normal karyotypes by both conventional and banding techniques; thus the origin of the ring chromosome could not be determined. Images PMID:604496

  16. Theodolite Ring Lights

    NASA Technical Reports Server (NTRS)

    Clark, David

    2006-01-01

    Theodolite ring lights have been invented to ease a difficulty encountered in the well-established optical-metrology practice of using highly reflective spherical tooling balls as position references. A theodolite ring light produces a more easily visible reflection and eliminates the need for an autocollimating device. A theodolite ring light is a very bright light source that is well centered on the optical axis of the instrument. It can be fabricated, easily and inexpensively, for use on a theodolite or telescope of any diameter.

  17. Recent developments in trapping and manipulation of atoms with adiabatic potentials

    NASA Astrophysics Data System (ADS)

    Garraway, Barry M.; Perrin, Hélène

    2016-09-01

    A combination of static and oscillating magnetic fields can be used to ‘dress’ atoms with radio-frequency (RF), or microwave, radiation. The spatial variation of these fields can be used to create an enormous variety of traps for ultra-cold atoms and quantum gases. This article reviews the type and character of these adiabatic traps and the applications which include atom interferometry and the study of low-dimensional quantum systems. We introduce the main concepts of magnetic traps leading to adiabatic dressed traps. The concept of adiabaticity is discussed in the context of the Landau-Zener model. The first bubble trap experiment is reviewed together with the method used for loading it. Experiments based on atom chips show the production of double wells and ring traps. Dressed atom traps can be evaporatively cooled with an additional RF field, and a weak RF field can be used to probe the spectroscopy of the adiabatic potentials. Several approaches to ring traps formed from adiabatic potentials are discussed, including those based on atom chips, time-averaged adiabatic potentials and induction methods. Several proposals for adiabatic lattices with dressed atoms are also reviewed.

  18. Magnetic trap for thulium atoms

    SciTech Connect

    Sukachev, D D; Sokolov, A V; Chebakov, K A; Akimov, A V; Kolachevskii, N N; Sorokin, Vadim N

    2011-08-31

    For the first time ultra-cold thulium atoms were trapped in a magnetic quadrupole trap with a small field gradient (20 Gs cm{sup -1}). The atoms were loaded from a cloud containing 4x10{sup 5} atoms that were preliminarily cooled in a magneto-optical trap to the sub-Doppler temperature of 80 {mu}K. As many as 4x10{sup 4} atoms were trapped in the magnetic trap at the temperature of 40 {mu}K. By the character of trap population decay the lifetime of atoms was determined (0.5 s) and an upper estimate was obtained for the rate constant of inelastic binary collisions for spin-polarised thulium atoms in the ground state (g{sub in} < 10{sup -11}cm{sup 3} s{sup -1}). (magnetic traps)

  19. Causes of Ring-Related Leg Injuries in Birds – Evidence and Recommendations from Four Field Studies

    PubMed Central

    Griesser, Michael; Schneider, Nicole A.; Collis, Mary-Anne; Overs, Anthony; Guppy, Michael; Guppy, Sarah; Takeuchi, Naoko; Collins, Pete; Peters, Anne; Hall, Michelle L.

    2012-01-01

    One of the main techniques for recognizing individuals in avian field research is marking birds with plastic and metal leg rings. However, in some species individuals may react negatively to rings, causing leg injuries and, in extreme cases, the loss of a foot or limb. Here, we report problems that arise from ringing and illustrate solutions based on field data from Brown Thornbills (Acanthiza pusilla) (2 populations), Siberian Jays (Perisoreus infaustus) and Purple-crowned Fairy-wrens (Malurus coronatus). We encountered three problems caused by plastic rings: inflammations triggered by material accumulating under the ring (Purple-crowned Fairy-wrens), contact inflammations as a consequence of plastic rings touching the foot or tibio-tarsal joint (Brown Thornbills), and toes or the foot getting trapped in partly unwrapped flat-band colour rings (Siberian Jays). Metal rings caused two problems: the edges of aluminium rings bent inwards if mounted on top of each other (Brown Thornbills), and too small a ring size led to inflammation (Purple-crowned Fairy-wrens). We overcame these problems by changing the ringing technique (using different ring types or larger rings), or using different adhesive. Additionally, we developed and tested a novel, simple technique of gluing plastic rings onto metal rings in Brown Thornbills. A review of studies reporting ring injuries (N = 23) showed that small birds (<55 g body weight) are more prone to leg infections while larger birds (>35 g) tend to get rings stuck over their feet. We give methodological advice on how these problems can be avoided, and suggest a ringing hazard index to compare the impact of ringing in terms of injury on different bird species. Finally, to facilitate improvements in ringing techniques, we encourage online deposition of information regarding ringing injuries of birds at a website hosted by the European Union for Bird Ringing (EURING). PMID:23300574

  20. Saturn's dynamic D ring

    USGS Publications Warehouse

    Hedman, M.M.; Burns, J.A.; Showalter, M.R.; Porco, C.C.; Nicholson, P.D.; Bosh, A.S.; Tiscareno, M.S.; Brown, R.H.; Buratti, B.J.; Baines, K.H.; Clark, R.

    2007-01-01

    The Cassini spacecraft has provided the first clear images of the D ring since the Voyager missions. These observations show that the structure of the D ring has undergone significant changes over the last 25 years. The brightest of the three ringlets seen in the Voyager images (named D72), has transformed from a narrow, <40-km wide ringlet to a much broader and more diffuse 250-km wide feature. In addition, its center of light has shifted inwards by over 200 km relative to other features in the D ring. Cassini also finds that the locations of other narrow features in the D ring and the structure of the diffuse material in the D ring differ from those measured by Voyager. Furthermore, Cassini has detected additional ringlets and structures in the D ring that were not observed by Voyager. These include a sheet of material just interior to the inner edge of the C ring that is only observable at phase angles below about 60??. New photometric and spectroscopic data from the ISS (Imaging Science Subsystem) and VIMS (Visual and Infrared Mapping Spectrometer) instruments onboard Cassini show the D ring contains a variety of different particle populations with typical particle sizes ranging from 1 to 100 microns. High-resolution images reveal fine-scale structures in the D ring that appear to be variable in time and/or longitude. Particularly interesting is a remarkably regular, periodic structure with a wavelength of ??? 30 ?? km extending between orbital radii of 73,200 and 74,000 km. A similar structure was previously observed in 1995 during the occultation of the star GSC5249-01240, at which time it had a wavelength of ??? 60 ?? km. We interpret this structure as a periodic vertical corrugation in the D ring produced by differential nodal regression of an initially inclined ring. We speculate that this structure may have formed in response to an impact with a comet or meteoroid in early 1984. ?? 2006 Elsevier Inc. All rights reserved.

  1. Ultrasonic Newton's rings

    SciTech Connect

    Hsu, D.K. ); Dayal, V. )

    1992-03-09

    Interference fringes due to bondline thickness variation were observed in ultrasonic scans of the reflected echo amplitude from the bondline of adhesively joined aluminum skins. To demonstrate that full-field interference patterns are observable in point-by-point ultrasonic scans, an optical setup for Newton's rings was scanned ultrasonically in a water immersion tank. The ultrasonic scan showed distinct Newton's rings whose radii were in excellent agreement with the prediction.

  2. Transport of ultracold atoms between concentric traps via spatial adiabatic passage

    NASA Astrophysics Data System (ADS)

    Polo, J.; Benseny, A.; Busch, Th; Ahufinger, V.; Mompart, J.

    2016-01-01

    Spatial adiabatic passage processes for ultracold atoms trapped in tunnel-coupled cylindrically symmetric concentric potentials are investigated. Specifically, we discuss the matter-wave analog of the rapid adiabatic passage (RAP) technique for a high fidelity and robust loading of a single atom into a harmonic ring potential from a harmonic trap, and for its transport between two concentric rings. We also consider a system of three concentric rings and investigate the transport of a single atom between the innermost and the outermost rings making use of the matter-wave analog of the stimulated Raman adiabatic passage (STIRAP) technique. We describe the RAP-like and STIRAP-like dynamics by means of a two- and a three-state model, respectively, obtaining good agreement with the numerical simulations of the corresponding two-dimensional Schrödinger equation.

  3. Bending the Rings

    NASA Technical Reports Server (NTRS)

    2005-01-01

    Saturn's rings appear strangely warped in this view of the rings seen through the upper Saturn atmosphere.

    The atmosphere acts like a lens in refracting (bending) the light reflected from the rings. As the rings pass behind the overexposed limb (edge) of Saturn as seen from Cassini, the ring structure appears to curve downward due to the bending of the light as it passes through the upper atmosphere.

    This image was obtained using a near-infrared filter. The filter samples a wavelength where methane gas does not absorb light, thus making the far-off rings visible through the upper atmosphere.

    By comparing this image to similar ones taken using filters where methane gas does absorb, scientists can estimate the vertical profile of haze and the abundance of methane in Saturn's high atmosphere.

    The image was taken in visible light with the Cassini spacecraft narrow-angle camera on April 14, 2005, through a filter sensitive to wavelengths of infrared light centered at 938 nanometers and at a distance of approximately 197,000 kilometers (123,000 miles) from Saturn. The image scale is 820 meters (2,680 feet) per pixel.

  4. Phylogenetics and evolution of nematode-trapping fungi (Orbiliales) estimated from nuclear and protein coding genes.

    PubMed

    Li, Yan; Hyde, Kevin D; Jeewon, Rajesh; Cai, Lei; Vijaykrishna, Dhanasekaran; Zhang, Keqin

    2005-01-01

    The systematic classification of nematode-trapping fungi is redefined based on phylogenies inferred from sequence analyses of 28S rDNA, 5.8S rDNA and beta-tubulin genes. Molecular data were analyzed with maximum parsimony, maximum likelihood and Bayesian analysis. An emended generic concept of nematode-trapping fungi is provided. Arthrobotrys is characterized by adhesive networks, Dactylellina by adhesive knobs, and Drechslerella by constricting-rings. Phylogenetic placement of taxa characterized by stalked adhesive knobs and non-constricting rings also is confirmed in Dactylellina. Species that produce unstalked adhesive knobs that grow out to form loops are transferred from Gamsylella to Dactylellina, and those that produce unstalked adhesive knobs that grow out to form networks are transferred from Gamsylella to Arthrobotrys. Gamsylella as currently circumscribed cannot be treated as a valid genus. A hypothesis for the evolution of trapping-devices is presented based on multiple gene data and morphological studies. Predatory and nonpredatory fungi appear to have been derived from nonpredatory members of Orbilia. The adhesive knob is considered to be the ancestral type of trapping device from which constricting rings and networks were derived via two pathways. In the first pathway adhesive knobs retained their adhesive material forming simple two-dimension networks, eventually forming complex three-dimension networks. In the second pathway adhesive knobs lost their adhesive materials, with their ends meeting to form nonconstricting rings and they in turn formed constricting rings with three inflated-cells.

  5. Atom trap trace analysis

    SciTech Connect

    Lu, Z.-T.; Bailey, K.; Chen, C.-Y.; Du, X.; Li, Y.-M.; O'Connor, T. P.; Young, L.

    2000-05-25

    A new method of ultrasensitive trace-isotope analysis has been developed based upon the technique of laser manipulation of neutral atoms. It has been used to count individual {sup 85}Kr and {sup 81}Kr atoms present in a natural krypton sample with isotopic abundances in the range of 10{sup {minus}11} and 10{sup {minus}13}, respectively. The atom counts are free of contamination from other isotopes, elements,or molecules. The method is applicable to other trace-isotopes that can be efficiently captured with a magneto-optical trap, and has a broad range of potential applications.

  6. Propellers in Saturn's rings

    NASA Astrophysics Data System (ADS)

    Sremcevic, M.; Stewart, G. R.; Albers, N.; Esposito, L. W.

    2014-04-01

    Theoretical studies and simulations have demonstrated the effects caused by objects embedded in planetary rings [5, 8]. Even if the objects are too small to be directly observed, each creates a much larger gravitational imprint on the surrounding ring material. These strongly depend on the mass of the object and range from "S" like propeller-shaped structures for about 100m-sized icy bodies to the opening of circumferential gaps as in the case of the embedded moons Pan and Daphnis and their corresponding Encke and Keeler Gaps. Since the beginning of the Cassini mission many of these smaller objects (~ 100m in size) have been identified in Saturn's A ring through their propeller signature in the images [10, 7, 9, 11]. Furthermore, recent Cassini observations indicate the possible existence of objects embedded even in Saturn's B and C ring [6, 2]. In this paper we present our new results about by now classical A ring propellers and more enigmatic B ring population. Due to the presence of self-gravity wakes the analysis of propeller brightness in ISS images always bears some ambiguity [7, 9] and consequently the exact morphology of propellers is not a settled issue. In 2008 we obtained a fortunate Cassini Ultraviolet Imaging Spectrograph (UVIS) occultation of the largest A ring propeller Bleriot. Utilizing Cassini ISS images we obtain Bleriot orbit and demonstrate that UVIS Persei Rev42 occultation did cut across Bleriot about 100km downstream from the center. The occultation itself shows a prominent partial gap and higher density outer flanking wakes, while their orientation is consistent with a downstream cut. While in the UVIS occultation the partial gap is more prominent than the flanking wakes, the features mostly seen in Bleriot images are actually flanking wakes. One of the most interesting aspects of the A ring propellers are their wanderings, or longitudinal deviations from a pure circular orbit [11]. We numerically investigated the possibility of simple moon

  7. The effects of the solar radiation pressure on the F-ring particles

    NASA Astrophysics Data System (ADS)

    Sfair, R.; Giuliatti Winter, S.

    The Saturn s F-ring is a narrow ring orbiting outside the main ring system of Saturn It is located between two close satellites Prometheus the interior one and Pandora The gravitational interactions between the ring particles and the satellites can be responsible for several structures found in this ring Showalter et al 1992 showed that the F-ring material could be divided into two regions a core composed by centimeter or large particles and a dust envelope composed by mu m particles Recent observations by Cassini instruments brought more complications to this region with the discovery of two new faint rings between the A ring and Prometheus one of these rings has the satellite Atlas embedded on it These new rings are tenuous like the dust envelope which surround the F-ring and the solar radiation force can play a significant role in this dynamical environment In this work we analysed the effects due to the solar radiation forces on the particles of the F ring and the two new discovered rings In this analysis we also included the perturbation of the satellite Prometheus on the F ring particles and the satellite Atlas on the new rings particles We have numerically simulated particles with size ranging from 1-500 mu m in radius The density of these particles was assumed to be 1g cm 3 Our results show that a sample of scattered F ring particles can be trapped due to Prometheus effects However the particles from the new discovered rings have a short lifetime due to the solar radiation pressure Only those particles coorbital to Atlas

  8. Observation of Cold Collisions between Trapped Ions and Trapped Atoms

    NASA Astrophysics Data System (ADS)

    Grier, Andrew T.; Cetina, Marko; Oručević, Fedja; Vuletić, Vladan

    2009-06-01

    We study cold collisions between trapped ions and trapped atoms in the semiclassical (Langevin) regime. Using Yb+ ions confined in a Paul trap and Yb atoms in a magneto-optical trap, we investigate charge-exchange collisions of several isotopes over three decades of collision energies down to 3μeV (kB×35mK). The minimum measured rate coefficient of 6×10-10cm3s-1 is in good agreement with that derived from a Langevin model for an atomic polarizability of 143 a.u.

  9. Thermal Replication Trap

    NASA Astrophysics Data System (ADS)

    Braun, Dieter

    2011-03-01

    The hallmark of living matter is the replication of genetic molecules and their active storage against diffusion. We have argued in the past that thermal convection can host the million-fold accumulation even of single nucleotides and at the same time trigger exponential replication. Accumulation is driven by thermophoresis and convection in elongated chambers, replication by the inherent temperature cycling in convection. Optothermal pumping [2,3] allows to implement the thermal trap efficiently in a toroidal or linear geometry. Based on this method, we were in a position to combine accumulation and replication of DNA in the same chamber. As we are missing a solid chemistry of prebiotic replication, we used as a proxy reaction for to replication the polymerase chain reaction. Convective flow both drives the DNA replicating polymerase chain reaction (PCR) while concurrent thermophoresis accumulates the replicated 143 base pair DNA in bulk solution. The time constant for accumulation is 92 s while DNA is doubled every 50 s. The length of the amplified DNA is checked with thermophoresis. Finite element simulations confirm the findings. The experiments explore conditions in pores of hydrothermal rock which can serve as a model environment for the origin of life and has prospects towards the first autonomous evolution, hosting the Darwin process by molecular selection using the thermophoretic trap. On the other side, the implemented continuous evolution will be able to breed well specified DNA or RNA molecules in the future.

  10. Nano trap for polar molecules

    NASA Astrophysics Data System (ADS)

    Blümel, R.

    2012-07-01

    A new ac/dc monopole trap for neutral polar particles, introduced and explored by Blümel (2011 Phys. Rev. A 83 045402 and 2011 Eur. Phys. J. D 64 85-101), is significantly advanced in several directions. (1) Previously shown to work only for polar classical particles and polar macro-molecules, the trap is shown to work for polar diatomic molecules. (2) A homogeneous electric field, optionally switched on for improved stability in the angular direction, leads to stable trapping in higher order stability regions of the Mathieu equation. (3) Based on the Floquet formalism, analytical and numerical calculations are presented that show that the trap is quantum mechanically stable. (4) Definition and derivation of a quantum pseudo-potential allow a qualitative understanding of the quantum trapping mechanism. (5) It is shown that the proposed ac/dc trap may be realized experimentally using currently available scanning tunnelling microscopy technology.

  11. Nanofriction in cold ion traps.

    PubMed

    Benassi, A; Vanossi, A; Tosatti, E

    2011-01-01

    Sliding friction between crystal lattices and the physics of cold ion traps are so far non-overlapping fields. Two sliding lattices may either stick and show static friction or slip with dynamic friction; cold ions are known to form static chains, helices or clusters, depending on the trapping conditions. Here we show, based on simulations, that much could be learnt about friction by sliding, through, for example, an electric field, the trapped ion chains over a corrugated potential. Unlike infinite chains, in which the theoretically predicted Aubry transition to free sliding may take place, trapped chains are always pinned. Yet, a properly defined static friction still vanishes Aubry-like at a symmetric-asymmetric structural transition, found for decreasing corrugation in both straight and zig-zag trapped chains. Dynamic friction is also accessible in ringdown oscillations of the ion trap. Long theorized static and dynamic one-dimensional friction phenomena could thus become accessible in future cold ion tribology.

  12. Ring correlations in random networks

    NASA Astrophysics Data System (ADS)

    Sadjadi, Mahdi; Thorpe, M. F.

    2016-12-01

    We examine the correlations between rings in random network glasses in two dimensions as a function of their separation. Initially, we use the topological separation (measured by the number of intervening rings), but this leads to pseudo-long-range correlations due to a lack of topological charge neutrality in the shells surrounding a central ring. This effect is associated with the noncircular nature of the shells. It is, therefore, necessary to use the geometrical distance between ring centers. Hence we find a generalization of the Aboav-Weaire law out to larger distances, with the correlations between rings decaying away when two rings are more than about three rings apart.

  13. Effects of fluctuating magnetic fields on a superconducting bulk rotor shielded with superconducting rings

    NASA Astrophysics Data System (ADS)

    Yamagishi, K.; Ogawa, J.; Tsukamoto, O.

    2014-05-01

    We study the effect of a fluctuating magnetic field, which is one of the technical problems for trapped magnetic fields in a bulk superconductor, to realize a practical bulk superconductor rotating machine. Previous research and other's research has shown that fluctuating magnetic fields reduce the strength of trapped magnetic fields in superconducting bulk modules [1, 2]. This deters development of applications of AC rotating machines because superconducting bulk modules are always exposed to a fluctuating magnetic field. Therefore, it is necessary to develop a method to control decrease of the trapped magnetic field. We propose a method to use the shielding ring of a superconducting wire to achieve this goal and the effects are confirmed experimentally [3]. We are now building test equipment for examining the performance of a shielding ring in a bulk rotating machine. This paper reports the test result for the shielding ring applied to the bulk superconducting rotor that is a part of the test equipment.

  14. DC-Powered Jumping Ring

    NASA Astrophysics Data System (ADS)

    Jeffery, Rondo N.; Amiri, Farhang

    2016-02-01

    The classroom jumping ring demonstration is nearly always performed using alternating current (AC), in which the ring jumps or flies off the extended iron core when the switch is closed. The ring jumps higher when cooled with liquid nitrogen (LN2). We have performed experiments using DC to power the solenoid and find similarities and significant differences from the AC case. In particular, the ring does not fly off the core but rises a short distance and then falls back. If the ring jumps high enough, the rising and the falling motion of the ring does not follow simple vertical motion of a projectile. This indicates that there are additional forces on the ring in each part of its motion. Four possible stages of the motion of the ring with DC are identified, which result from the ring current changing directions during the jump in response to a changing magnetic flux through the moving ring.

  15. Near-field waveguide trapping and tracking of particles using fluorescence imaging

    NASA Astrophysics Data System (ADS)

    Ahluwalia, Balpreet S.; Brox, Petter; Helle, Øystein; Tinguely, Jean-Claude; Hellesø, Olav G.

    2014-02-01

    The evanescent field from an optical waveguide is used for near-field trapping and transporting of fluorescent microspheres. Out-of-focus fluorescence imaging is used to track the trapped particle in 3-D with nanometer precision (<100 nm). A prior calibration is done to determine the relationship between the z-coordinate and the radius of the outermost diffraction ring in the image of the sphere. This gives precise information about how much the particle moves up and down during propulsion along the waveguide. Results are presented for trapping and tracking a 1 μm fluorescent particle on a strip waveguide.

  16. Propellers in Saturn's rings

    NASA Astrophysics Data System (ADS)

    Sremcevic, M.; Stewart, G. R.; Albers, N.; Esposito, L. W.

    2013-12-01

    Theoretical studies and simulations have demonstrated the effects caused by objects embedded in planetary rings. Even if the objects are too small to be directly observed, each creates a much larger gravitational imprint on the surrounding ring material. These strongly depend on the mass of the object and range from "S" like propeller-shaped structures for about 100m-sized icy bodies to the opening of circumferential gaps as in the case of the embedded moons Pan and Daphnis and their corresponding Encke and Keeler Gaps. Since the beginning of the Cassini mission many of these smaller objects (~<500m in size) have been indirectly identified in Saturn's A ring through their propeller signature in the images. Furthermore, recent Cassini observations indicate the possible existence of objects embedded even in Saturn's B and C ring. In this paper we present evidence for the existence of propellers in Saturn's B ring by combining data from Cassini Ultraviolet Imaging Spectrograph (UVIS) and Imaging Science Subsystem (ISS) experiments. We show evidence that B ring seems to harbor two distinct populations of propellers: "big" propellers covering tens of degrees in azimuth situated in the densest part of B ring, and "small" propellers in less dense inner B ring that are similar in size and shape to known A ring propellers. The population of "big" propellers is exemplified with a single object which is observed for 5 years of Cassini data. The object is seen as a very elongated bright stripe (40 degrees wide) in unlit Cassini images, and dark stripe in lit geometries. In total we report observing the feature in images at 18 different epochs between 2005 and 2010. In UVIS occultations we observe this feature as an optical depth depletion in 14 out of 93 occultation cuts at corrotating longitudes compatible with imaging data. Combining the available Cassini data we infer that the object is a partial gap located at r=112,921km embedded in the high optical depth region of the B

  17. In vitro evaluation of a passive radio frequency identification microchip implanted in human molars subjected to compression forces, for forensic purposes of human identification

    PubMed Central

    Moreno, Freddy; Vallejo, Diego; Garzón, Herney; Moreno, Sandra

    2013-01-01

    Objective: To evaluate the in vitro behavior of a passive Radio Frequency Identification (RFID) microchip implanted in human molars subjected to compression forces to determine its technical and clinical viability. Materials and Methods: In vitro experimental study to evaluate the physical behavior of a passive RFID microchip (VeriChip™) implanted in human molars through resin restoration (Filtek P90™ Silorane 3M-ESPE®) to determine the clinical and technical possibilities of the implant and the viability to withstand compression forces exerted by the stomatognathic system during mastication. Results: Through the ANOVA test, it was found that the teeth on which a microchip was implanted show great resistance to compressive forces. It was also evident that teeth with microchips implanted in Class V cavities are more resistant than those implanted in Class I cavities. Conclusions: Although microchip dimensions are big, requiring a sufficiently large cavity, from the biomechanical point of view it is plausible to implant a microchip in a Class V cavity employing restoration material based on resin for forensic purposes of human identification. PMID:24255554

  18. Gated charged-particle trap

    DOEpatents

    Benner, W. Henry

    1999-01-01

    The design and operation of a new type of charged-particle trap provides simultaneous measurements of mass, charge, and velocity of large electrospray ions. The trap consists of a detector tube mounted between two sets of center-bored trapping plates. Voltages applied to the trapping plates define symmetrically-opposing potential valleys which guide axially-injected ions to cycle back and forth through the charge-detection tube. A low noise charge-sensitive amplifier, connected to the tube, reproduces the image charge of individual ions as they pass through the detector tube. Ion mass is calculated from measurement of ion charge and velocity following each passage through the detector.

  19. DNA Separation Using Photoelectrophoretic Traps

    SciTech Connect

    Braiman, Avital; Thundat, Thomas George; Rudakov, Fedor M

    2011-01-01

    In our recent publications we presented a design that allows formation of highly localized and optically controlled electrophoretic traps. 1,2 We demonstrated that electrophoretic traps can be utilized for biomolecule photoconcentration, optically directed transport, and separation by size. 1,2 In the current publication we suggest a hybrid design for biomolecule separation which implements electrophoretic traps in tandem with well-established electrophoretic techniques. We perform Monte Carlo simulations that demonstrate that the resolution of well-established electrophoretic techniques can be greatly enhanced by introducing photoelectrophoretic traps.

  20. Geomagnetically trapped anomalous cosmic rays

    SciTech Connect

    Selesnick, R.S.; Cummings, A.C.; Cummings, J.R.

    1995-06-01

    Since its launch in July 1992, the polar-orbiting satellite SAMPEX has been collecting data on geomagnetically trapped heavy ions, predominantly O, N, and Ne, at energies {ge}15 MeV/nucleon and in a narrow L shell range L = 2. Their location, elemental composition, energy spectra, pitch angle distribution, and time variations all support the theory that these particles originated as singly ionized interplanetary anomalous cosmic rays that were stripped of electrons in the Earth`s upper atmosphere and subsequently trapped. The O are observed primarily at pitch angles outside the atmospheric loss cones, consistent with a trapped population, and their distribution there is nearly isotropic. The abundances relative to O of the N, possible Ne, and especially C are lower than the corresponding interplanetary values, which may be indicative of the trapping efficiencies. The distributions of trapped N, O, and Ne in energy and L shell suggest that most of the ions observed at the SAMPEX altitude of {approximately}600 km are not fully stripped when initially trapped. A comparison of the trapped intensity with the much lower interplanetary intensity of anomalous cosmic rays provides model-dependent estimates of the product of the trapping probability and the average trapped particle lifetime against ionization losses in the residual atmosphere for particles that mirror near the SAMPEX altitude. 36 refs., 13 figs., 1 tab.