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Sample records for microchip ring trap

  1. Adjustable microchip ring trap for cold atoms and molecules

    SciTech Connect

    Baker, Paul M.; Stickney, James A.; Squires, Matthew B.; Scoville, James A.; Carlson, Evan J.; Buchwald, Walter R.; Miller, Steven M.

    2009-12-15

    We describe the design and function of a circular magnetic waveguide produced from wires on a microchip for atom interferometry using de Broglie waves. The guide is a two-dimensional magnetic minimum for trapping weak-field seeking states of atoms or molecules with a magnetic dipole moment. The design consists of seven circular wires sharing a common radius. We describe the design, the time-dependent currents of the wires and show that it is possible to form a circular waveguide with adjustable height and gradient while minimizing perturbation resulting from leads or wire crossings. This maximal area geometry is suited for rotation sensing with atom interferometry via the Sagnac effect using either cold atoms, molecules and Bose-condensed systems.

  2. A Microchip Ring Trap for Cold Atoms

    DTIC Science & Technology

    2005-09-05

    geometry is suited for rotation sensing with atom interferometry via the Sagnac effect using either cold thermal atoms and molecules or Bose-condensed...crossings. This maximal area geometry is suited for rotation sensing with atom interferomettry via the Sagnac effect using either cold thermal atoms and...interferometry is the gyroscope. Using the Sagnac effect , the theoretical sensitivity of an atom interferometer bests that of a light interferometer of the same

  3. Proposed magnetoelectrostatic ring trap for neutral atoms

    SciTech Connect

    Hopkins, Asa; Lev, Benjamin; Mabuchi, Hideo

    2004-11-01

    We propose a trap for confining cold neutral atoms in a microscopic ring using a magnetoelectrostatic potential. The trapping potential is derived from a combination of a repulsive magnetic field from a hard drive atom mirror and the attractive potential produced by a charged disk patterned on the hard drive surface. We calculate a trap frequency of [29.7,42.6,62.8] kHz and a depth of [16.1,21.8,21.8] MHz for [{sup 133}Cs, {sup 87}Rb, {sup 40}K], and discuss a simple loading scheme and a method for fabrication. This device provides a one-dimensional potential in a ring geometry that may be of interest to the study of trapped quantum degenerate one-dimensional gases.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Nano-ring arrays for sub-micron particle trapping

    NASA Astrophysics Data System (ADS)

    Han, Xue; Truong, Viet Giang; Nic Chormaic, Síle

    2017-04-01

    Plasmonic tweezers based on nano-ring arrays on gold thin film are demonstrated. A cylindrical surface plasmon resonance is generated in the aperture of a nano-ring and a transmission peak results. When nano-slits are included to connect the nano-rings, the transmission peak becomes narrower. When the size of the aperture of the nano-ring is reduced, this peak is red-shifted. Both 0.5 μm and 1 μm polystyrene particles are trapped successfully by nano-ring arrays. A self-induced back-action effect is observed when a red-shifted laser beam is used. With multiple trapping sites provided by the nano-ring array, this type of plasmonic tweezers has huge potential to be integrated in lab-on-a-chip systems for life sciences research.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Swelling of two-dimensional polymer rings by trapped particles.

    PubMed

    Haleva, E; Diamant, H

    2006-09-01

    The mean area of a two-dimensional Gaussian ring of N monomers is known to diverge when the ring is subject to a critical pressure differential, p c ~ N -1. In a recent publication (Eur. Phys. J. E 19, 461 (2006)) we have shown that for an inextensible freely jointed ring this divergence turns into a second-order transition from a crumpled state, where the mean area scales as [A]~N-1, to a smooth state with [A]~N(2). In the current work we extend these two models to the case where the swelling of the ring is caused by trapped ideal-gas particles. The Gaussian model is solved exactly, and the freely jointed one is treated using a Flory argument, mean-field theory, and Monte Carlo simulations. For a fixed number Q of trapped particles the criticality disappears in both models through an unusual mechanism, arising from the absence of an area constraint. In the Gaussian case the ring swells to such a mean area, [A]~ NQ, that the pressure exerted by the particles is at p c for any Q. In the freely jointed model the mean area is such that the particle pressure is always higher than p c, and [A] consequently follows a single scaling law, [A]~N(2) f (Q/N), for any Q. By contrast, when the particles are in contact with a reservoir of fixed chemical potential, the criticality is retained. Thus, the two ensembles are manifestly inequivalent in these systems.

  15. 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).

  16. Confinement of Nonneutral Plasmas in the Prototype Ring Trap Device

    SciTech Connect

    Haruhiko Himura; Zensho Yoshida; Chihiro Nakashima; Junji Morikawa Hidekazu Kakuno; Shigeru Tahara; Norihisa Shibayama

    1999-12-31

    Recently, an internal-ring device named Proto-RT (Prototype Ring Trap) was constructed at University of Tokyo, and experiments on the device have been intensively conducted. The main goal of Proto-RT is to explore an innovative method to attain a plasma equilibrium with extremely high-{beta} ({beta} > 1) in a toroidal geometry using non-neutral condition. At the first series of the experiments, pure electron plasmas (n{sub e} {similar_to} 10{sup 13} m{sup {minus}3}) have been successfully confined inside a separatrix. No disruption is so far observed. The confinement time of the electron plasmas is of order 0.1 ms for an X point configuration. The non-neutrality of {triangle}n{sub e} {similar_to} 10{sup 13} m{sup -3} is already beyond the critical value which is required to produce enough self-electric field E in non-neutral plasmas with n{sub 0} {similar_to} 10{sup 19} m{sup -3}, causing a strong E x B flow thoroughly over the plasmas where the hydrodynamic pressure of the flow is predicted to balance with the thermal pressure of the plasmas.

  17. Confinement of nonneutral plasmas in the Prototype Ring Trap device

    SciTech Connect

    Himura, Haruhiko; Yoshida, Zensho; Nakashima, Chihiro; Morikawa, Junji; Kakuno, Hidekazu; Tahara, Shigeru; Shibayama, Norihisa

    1999-12-10

    Recently, an internal-ring device named Proto-RT (Prototype Ring Trap) was constructed at University of Tokyo, and experiments on the device have been intensively conducted. The main goal of Proto-RT is to explore an innovative method to attain a plasma equilibrium with extremely high-{beta}({beta}>1) in a toroidal geometry using non-neutral condition. At the first series of the experiments, pure electron plasmas (n{sub e}{approx}10{sup 13} m{sup -3}) have been successfully confined inside a separatrix. No disruption is so far observed. The confinement time of the electron plasmas is of order 0.1 ms for an X point configuration. The non-neutrality of {delta}n{sub e}{approx}10{sup 13} m{sup -3} is already beyond the critical value which is required to produce an enough self-electric field E in non-neutral plasmas with n{sub 0}{approx}10{sup 19} m{sup -3}, causing a strong ExB flow thoroughly over the plasmas where the hydrodynamic pressure of the flow is predicted to balance with the thermal pressure of the plasmas.

  18. Ionspray microchip.

    PubMed

    Pól, Jaroslav; Kauppila, Tiina J; Franssila, Sami; Kotiaho, Tapio; Kostiainen, Risto

    2010-09-15

    An ionspray microchip is introduced. The chip is based on the earlier presented nebulizer microchip that consists of glass and silicon plates bonded together. A liquid inlet channel, nebulizer gas inlet, and nozzle are etched on the silicon plate and a platinum heater is integrated on the glass plate. The nebulizer microchip has been previously used in atmospheric pressure chemical ionization, atmospheric pressure photoionization, sonic spray ionization, and thermospray ionization modes. In this work we show that the microchip can be operated also in ionspray mode by introducing high voltage to the silicon plate of the microchip. The effects of operation parameters (voltage, nebulizer gas pressure, sample solution flow rate, solvent composition, and analyte concentration) on the performance of the ion spray microchip were studied. Under optimized conditions the microchip provides efficient ionization of small and large compounds and good quantitative performance. The feasibility of the ion spray microchip in liquid chromatography/mass spectrometry (LC/MS) was demonstrated by the analysis of tryptic peptides of bovine serum albumin. Copyright 2010 John Wiley & Sons, Ltd.

  19. 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.

  20. 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

  1. 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.

  2. 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.

  3. 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)

  4. 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.

  5. A new ring-shape high-temperature superconducting trapped-field magnet

    NASA Astrophysics Data System (ADS)

    Sheng, Jie; Zhang, Min; Wang, Yawei; Li, Xiaojian; Patel, Jay; Yuan, Weijia

    2017-09-01

    This paper presents a new trapped-field magnet made of second-generation high-temperature superconducting (2G HTS) rings. This so-called ring-shape 2G HTS magnet has the potential to provide much stronger magnetic fields relative to existing permanent magnets. Compared to existing 2G HTS trapped- field magnets, e.g. 2G HTS bulks and stacks, this new ring-shape 2G HTS magnet is more flexible in size and can be made into magnets with large dimensions for industrial applications. Effective magnetization is the key to being able to use trapped-field magnets. Therefore, this paper focuses on the magnetization mechanism of this new magnet using both experimental and numerical methods. Unique features have been identified and quantified for this new type of HTS magnet in the field cooling and zero field cooling process. The magnetization mechanism can be understood by the interaction between shielding currents and the penetration of external magnetic fields. An accumulation in the trapped field was observed by using multiple pulse field cooling. Three types of demagnetization were studied to measure the trapped-field decay for practical applications. Our results show that this new ring-shape HTS magnet is very promising in the trapping of a high magnetic field. As a super-permanent magnet, it will have a significant impact on large-scale industrial applications, e.g. the development of HTS machines with a very high power density and HTS magnetic resonance imaging devices.

  6. 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.

  7. 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.

  8. 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.

  9. Microchip Lasers

    DTIC Science & Technology

    2016-10-31

    physics that underlies their performance, typical operating parameters for the devices, and several of their applications . Keywords Composite-cavity...laser, Diode -pumped laser, Laser, Microchip laser, Miniature laser, Monolithic laser, Passively Q-switched laser, Q-switched laser, Saturable...cavity mirrors are deposited directly on the gain medium and the laser is pumped with a diode laser, either directly, as shown in Fig. 1, or via an

  10. 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.

  11. 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.

  12. 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.

  13. 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).

  14. Saturnian trapped radiation and its absorption by satellites and rings: the first results from pioneer 11.

    PubMed

    Simpson, J A; Bastian, T S; Chenette, D L; Lentz, G A; McKibben, R B; Pyle, K R; Tuzzolino, A J

    1980-01-25

    Electrons and protons accelerated and trapped in a Saturnian magnetic field have been found by the University of Chicago experiments on Pioneer 11 within 20 Saturn radii (Rs) of the planet. In the innermost regions, strong absorption effects due to satellites and ring material were observed, and from approximately 4 Rs inwards to the outer edge of the A ring at 2.30 Rs (where the radiation is absorbed), the intensity distributions of protons (>/= 0.5 million electron volts) and electrons (2 to 20 million electron volts) were axially symmetric, consistent with a centered dipole aligned with the planetary rotation axis. The maximum fluxes observed for protons (> 35 million electron volts and for electrons < 3.4 million electron volts) were 3 x 10(4) and 3 x 10(6) per square centimeter per second, respectively. Absorption of radiation by Mimas provides a means of estimating the radial diffusion coefficient for charged particle transport. However, the rapid flux increases observed between absorption features raise new questions concerning the physics of charged particle transport and acceleration. An absorption feature near 2.5 Rs has led to the discovery of a previously unknown satellite with a diameter of approximately 200 kilometers, semimajor axis of 2.51 Rs, and eccentricity of 0.013. Radiation absorption features that suggest a nonuniform distribution of matter around Saturn have also been found from 2.34 to 2.36 Rs, near the position of the F ring discovered by the Pioneer imaging experiment. Beneath the A, B, and C rings we continued to observe a low flux of high-energy electrons. We conclude that the inner Saturn magnetosphere, because of its near-axial symmetry and the many discrete radiation absorption regions, offers a unique opportunity to study the acceleration and transport of charged particles in a planetary magnetic field.

  15. 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.

  16. 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.

  17. 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)

  18. Central ring electrode for trapping and excitation/detection in Fourier transform ion cyclotron resonance mass spectrometry.

    PubMed

    Ostrander, C M; Arkin, C R; Laude, D

    2001-01-01

    The use of a central trapping ring electrode for Fourier transform ion cyclotron resonance (FTICR) mass spectrometry is demonstrated. Ions are trapped with an oppositely biased static potential superimposed on both the excite and detect electrodes and maintained throughout the experiment, including the application of a dipolar rf excite waveform and the image current ion detection event. The use of a central trapping electrode for FTICR coupled with an open cell design retains the advantages of high ion throughput and gas conductance, while simplifying the electrode geometry and reducing the overall dimensions of the cell. This allows the central trapping electrode to be of utility in volume-limited vacuum chambers including FTICR instrument miniaturization. Presented here are the preliminary experimental results using the central trapping electrode as an FTICR cell in which the excitation and detection electrodes also create a trapping depression to constrain the z-axis motion of the ions. The cell overcomes the principle limitation of an earlier single trapping electrode design by producing a 91% effective potential well depth compared to 19% for the single trapping electrode and 33% for standard open cells. This allows the central trapping electrode configuration to achieve an order of magnitude improvement in ion capacity compared to more conventional open cell designs.

  19. 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.

  20. 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.

  1. Generating electrospray from microchip devices using electroosmotic pumping

    SciTech Connect

    Ramsey, R.S.; Ramsey, J.M.

    1997-03-15

    A method of generating electrospray from solutions emerging from small channels etched on planer substrates in described. The fluids are delivered using electroosmotically induced pressures and are sprayed electrostatically from the terminus of a channel by applying an electrical potential of sufficient amplitude to generate the electrospray between the microchip and a conductor spaced from the channel terminus. No major modification of the microchip is required other than to expose a channel opening. The principles that regulate the fluid delivery are described and demonstrated. A spectrum for a test compound, tetrabutylammonium iodide, that was continuously electrophoresed was obtained by coupling the microchip to an ion trap mass spectrometer. 35 refs., 6 figs.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. Photonic crystal microchip laser

    NASA Astrophysics Data System (ADS)

    Gailevicius, D.; Koliadenko, V.; Purlys, V.; Peckus, M.; Taranenko, V.; Staliunas, K.

    2017-02-01

    The microchip lasers, being 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 we propose that specially designed photonic crystal in the cavity of a microchip laser, can significantly improve the beam quality. We experimentally show that a microchip laser, due to spatial filtering functionality of intracavity photonic crystal, improves the beam quality factor M2 reducing it by factor of 2, and thus increase the brightness of radiation by a factor of 4. This comprises a new kind of laser, the "photonic crystal microchip laser", a very compact and efficient light source emitting high spatial high brightness radiation.

  11. 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.

  12. 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

  13. Detection of telomerase activity using microchip electrophoresis.

    PubMed

    Karasawa, Koji; Arakawa, Hidetoshi

    2015-07-01

    Telomerase participates in malignant transformation or immortalization of cells and thus has attracted attention as an anticancer drug target and diagnostic tumor marker. The telomeric repeat amplification protocol (TRAP) and improved TRAP methods (TRAP-fluorescence, TRAP-hybridization, etc.) are widely used forms of this telomerase assay. However, these approaches generally employ acrylamide gel electrophoresis after amplification of telomeric repeats by polymerase chain reaction (PCR), making these TRAP methods time consuming and technically demanding. In this study we developed a novel telomerase assay using microchip electrophoresis for rapid and highly sensitive detection of telomerase activity in cancer cells. The mixed gel of 0.8% hydroxypropyl methylcellulose (HPMC) and 0.3% polyethylene oxide (PEO) with SYBR Gold (fluorescent reagent) was used for microchip electrophoresis. As a result, the product amplified by a telomerase-positive cell could be measured in one cell per assay and detected with high reproducibility (CV=0.67%) in the short time of 100s. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Trapping Ring Electrode Cell: A FTICR Mass Spectrometer Cell for Improved Signal-to-Noise and Resolving Power

    PubMed Central

    Weisbrod, Chad R.; Kaiser, Nathan K.; Skulason, Gunnar E.; Bruce, James E.

    2010-01-01

    A novel FTICR cell called the trapping ring electrode cell (TREC) has been conceived, simulated, developed, and tested. The performance of the TREC is compared to a closed cylindrical cell at different excited cyclotron radii. The TREC permits the ability to maintain coherent ion motion at larger initial excited cyclotron radii by decreasing the change in radial electric field with respect to z-axis position in the cell. This is accomplished through postexcitation modulation of the trapping potentials applied to segmented trap plates. Resolving power approaching the theoretical limit was achieved using the novel TREC technology; over 420 000 resolving power was observed on melittin [M + 4H]4+ species when employed under modest magnetic field strength (3T) and a data acquisition duration of 13 s. A 10-fold gain in signal-to-noise ratio is demonstrated over the closed cylindrical cell optimized with common potentials on all ring electrodes. The observed frequency drift during signal acquisition over long time periods was also significantly reduced, resulting in improved resolving power. PMID:18681460

  15. Microlensed microchip VECSEL.

    PubMed

    Laurand, Nicolas; Lee, C L; Gu, E; Hastie, J E; Calvez, Stephane; Dawson, Martin D

    2007-07-23

    We report a 1.055-mum microchip VECSEL array which uses a microlens-patterned diamond both as a heatspreader and as an array of concave output mirrors. This configuration, which is suitable for laser array operation, is here exploited to perform a systematic study of a set of microchip lasers with the same semiconductor structure but different cavity properties. The transverse mode selection of individual VECSELs is found to depend on the mode-matching conditions and on the microlens aperture size. Mode-matched single-device emission in the fundamental mode (M2~1.1) with pump-limited output power of 70 mW is demonstrated.

  16. 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.

  17. 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.

  18. Effects of radiation from a radiofrequency identification (RFID) microchip on human cancer cells.

    PubMed

    Lai, Henry C; Chan, Ho Wing; Singh, Narendra P

    2016-01-01

    Radiofrequency identification (RFID) microchips are used to remotely identify objects, e.g. an animal in which a chip is implanted. A passive RFID microchip absorbs energy from an external source and emits a radiofrequency identification signal which is then decoded by a detector. In the present study, we investigated the effect of the radiofrequency energy emitted by a RFID microchip on human cancer cells. Molt-4 leukemia, BT474 breast cancer, and HepG2 hepatic cancer cells were exposed in vitro to RFID microchip-emitted radiofrequency field for 1 h. Cells were counted before and after exposure. Effects of pretreatment with the spin-trap compound N-tert-butyl-alpha-phenylnitrone or the iron-chelator deferoxamine were also investigated. Results We found that the energy effectively killed/retarded the growth of the three different types of cancer cells, and the effect was blocked by the spin-trap compound or the iron-chelator, whereas an inactive microchip and energy from the external source had no significant effect on the cells. Conclusions Data of the present study suggest that radiofrequency field from the microchip affects cancer cells via the Fenton Reaction. Implantation of RFID microchips in tumors may provide a new method for cancer treatment.

  19. 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).].

  20. 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.

  1. 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.

  2. 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.

  3. Self-trapping of electrons in vortex rings in liquid helium

    NASA Astrophysics Data System (ADS)

    Khrapak, A. G.; Bronin, S. Ya.

    2017-06-01

    A model according to which "fast" and "exotic" negative ions in superfluid helium are the localized states of electrons in vortex rings has been presented. The quantization of radial and longitudinal motions of electrons inside the vortex core and the quantization of the vortex motion of liquid helium lead to the existence of a whole family of excited states of electron vortices, in qualitative agreement with the experiments on the mobility of exotic ions. The possibility of the verification of conclusions of the model in optical experiments has been considered.

  4. Finite temperature expansion dynamics of Bose-Einstein condensates in ring traps

    NASA Astrophysics Data System (ADS)

    Roy, Arko; Angom, D.

    2017-08-01

    We explore the effects of finite temperature on the dynamics of Bose-Einstein condensates (BECs) after it is released from the confining potential. In addition, we examine the variation in the expansion dynamics of the BECs as the confining potential is transformed from a multiply to a simply connected geometry. To include the effects of finite temperatures we use the frozen thermal cloud approximation, and observe unique features of the condensate density distribution when released from the confining potential. We find that at T ≠ 0, during the initial stages of expansion, the multiply connected condensate has more pronounced interference rings compared to the case of zero temperature. Such difference in the dynamical evolution is also evident for simply connected condensates.

  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. Red microchip VECSEL array.

    PubMed

    Hastie, Jennifer; Morton, Lynne; Calvez, Stephane; Dawson, Martin; Leinonen, Tomi; Pessa, Markus; Gibson, Graham; Padgett, Miles

    2005-09-05

    We report an InGaP/AlInGaP/GaAs microchip vertical-external-cavity surface emitting laser operating directly at red wavelengths and demonstrate its potential for array-format operation. Optical pumping with up to 3.3W at 532nm produced a maximum output power of 330mW at 675nm, in a single circularly-symmetric beam with M2<2. Simultaneous pumping with three separate input beams, generated using a diffractive optical element, achieved lasing from three discrete areas of the same chip. Output power of ~95mW per beam was obtained from this 3x1 array, each beam having a Gaussian intensity profile with M2<1.2. In a further development, a spatial light modulator allowed computer control over the orientation and separation of the pump beams, and hence dynamic control over the configuration of the VECSEL array.

  8. 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.

  9. 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.

  10. 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.

  11. Microchip electrophoresis for wine analysis.

    PubMed

    Gomez, Federico J V; Silva, M Fernanda

    2016-12-01

    The present critical review provides a summary of representative articles describing the analysis of wine by microchip electrophoresis. Special emphasis has been given to those compounds able to provide background information to achieve the differentiation of wines according to botanical origin, provenance, vintage and quality or assure wine authentication. This review focuses on capillary electrophoresis (CE) microchips dedicated to the analysis of wine covering all the contributions concerning this area. The most relevant compounds in wine analysis such as phenols, organic acids, inorganic species, aldehydes, sugars, alcohols, and neuroactive amines were considered. Moreover, a special section is dedicated to the potential of CE microchip for wine classification. Indeed, potential directions for the future are discussed.

  12. Microchip capillary electrophoresis/electrochemistry.

    PubMed

    Lacher, N A; Garrison, K E; Martin, R S; Lunte, S M

    2001-08-01

    Microfabricated fluidic devices have generated considerable interest over the past ten years due to the fact that sample preparation, injection, separation, derivatization, and detection can be integrated into one miniaturized device. This review reports progress in the development of microfabricated analytical systems based on microchip capillary electrophoresis (CE) with electrochemical (EC) detection. Electrochemical detection has several advantages for use with microchip electrophoresis systems, for example, ease of miniaturization, sensitivity, and selectivity. In this review, the basic components necessary for microchip CEEC are described, including several examples of different detector configurations. Lastly, details of the application of this technique to the determination of catechols and phenols, amino acids, peptides, carbohydrates, nitroaromatics, polymerase chain reaction (PCR) products, organophosphates, and hydrazines are described.

  13. Filmy channel microchip with amperometric detection.

    PubMed

    Wang, Wei; Fu, Feng F U; Xu, Xueqin; Lin, Jin-Ming; Chen, Guonan

    2009-11-01

    In this article, a new type of microchip with filmy channels and a sample-injection fracture is introduced. Unlike commercial microchip, new microchip possessed filmy channel with width 2-3 mm. The effective cooling ability made filmy channel microchip restrain the generation of Joule heat even under electric field of 588 V/cm. Moreover, wider channel could be more easily modified to prevent the absorption of samples, load more samples and result in a higher sensitivity. Sample-injection fracture was first applied to match the filmy channel in microchip. Equipped with an amperometric detector, the characteristics of the newly designed filmy channel microchip had been studied and the results showed that it had good reproducibility, higher sensitivity and excellent separation ability. The microchip was also applied to separate L-tryptophan's metabolites, namely 5-hydroxy-L-tryptophan, 5-hydroxytryptamine and 5-hydroxy-indole-3-acetic acid.

  14. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-10-01

    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 40Ca+ 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 40Ca+ 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.

  16. 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.

  17. 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);…

  18. 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);…

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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…

  5. 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

  6. 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.

  7. 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. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. 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.

  9. NcRNA-microchip analysis

    PubMed Central

    Mrázek, Jan; Vorwerk, Sonja

    2010-01-01

    Epstein-Barr virus (EBV) infection of human B cells requires the presence of non-coding RNAs (ncRNAs), which regulate expression of viral and host genes. To identify differentially expressed regulatory ncRNAs involved in EBV infection, a specialized cDNA library, enriched for ncRNAs derived from EBV-infected cells, was subjected to deep-sequencing. From the deep-sequencing analysis, we generated a custom-designed ncRNA-microchip to investigate differential expression of ncRNA candidates. By this approach, we identified 25 differentially expressed novel host-encoded ncRNA candidates in EBV-infected cells, comprised of six non-repeat-derived and 19 repeat-derived ncRNAs. Upon EBV infection of B cells, we also observed increased expression levels of oncogenic miRNAs mir-221 and mir-222, which might contribute to EBV-related tumorigenesis, as well as decreased expression levels of RNase P RNA, a ribozyme involved in tRNA maturation. Thus, in this study we demonstrate that our ncRNA-microchip approach serves as a powerful tool to identify novel differentially expressed ncRNAs acting as potential regulators of gene expression during EBV infection. PMID:21037422

  10. 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.

  11. 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.

  12. 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.

  13. Mutation detection using ligase chain reaction in passivated silicon-glass microchips and microchip capillary electrophoresis.

    PubMed

    Lou, Xing Jian; Panaro, Nicholas J; Wilding, Peter; Fortina, Paolo; Kricka, Larry J

    2004-09-01

    The ligase chain reaction (LCR) following PCR is one of the most sensitive and specific methods for detecting mutations, especially single nucleotide polymorphisms (SNPs). Performing LCR in microchips remains a challenge because of the inhibitory effect of the internal surfaces of silicon-glass microchips. We have tested a dynamic polymer-based surface passivation method for LCR conducted in oxide-coated silicon-glass microchips. The combination of polyvinylpyrrolidone 40 (PVP-40) at 0.75% (w/v) with an excess of the ligase produced successful LCR in the silicon-glass microchips, with yields of ligated primers comparable to reactions performed in conventional reaction tubes. Ligated primers were detected and quantified simply and conveniently using microchip capillary electrophoresis.

  14. 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.

  15. Dusty D Ring

    NASA Image and Video Library

    2014-02-24

    Saturn D ring is easy to overlook since it trapped between the brighter C ring and the planet itself. In this view from NASA Cassini spacecraft, all that can be seen of the D ring is the faint and narrow arc as it stretches from top right of the ima

  16. Floating resistivity detector for microchip electrophoresis.

    PubMed

    Tay, Elaine Teng Teng; Law, Wai Siang; Sim, Steven Poh Chuen; Feng, Huatao; Zhao, Jian Hong; Li, Sam Fong Yau

    2007-12-01

    A newly developed conductivity detector, the floating resistivity detector (FRD), for microchip electrophoresis was introduced in this work. The detector design permits decoupling of the detection circuit from the high separation voltage without compromising separation efficiency. This greatly simplifies the integration of microchip electrophoresis systems. Its method of detection relies on platinum electrodes being dipped in two buffer-filled branched detection probe reservoirs on the microchip device. In this way, analytes passing through the detection window will not pass through and subsequently adsorb onto the electrodes, alleviating problems of electrode fouling due to analyte contamination and surface reactions. A customized microchip design was proposed and optimized stepwise for the new FRD system. Each branched detection probe was determined to be 4.50 mm long with a 0.075 mm detection window gap between them. The distance between the detection window and buffer waste reservoir was determined to be 1.50 mm. The optimized microchip design was subsequently used in the analysis of four groups of analytes - inorganic cations, amino acids, aminoglycosides antibiotics, and biomarkers. Based on the preliminary results obtained, the detection limits were in the range of 0.4-0.7 mg/L for the inorganic cations and 1.5-15 mg/L for the amino compounds.

  17. Recent advances in microchip electrophoresis for amino acid analysis.

    PubMed

    Ou, Gaozhi; Feng, Xiaojun; Du, Wei; Liu, Xin; Liu, Bi-Feng

    2013-10-01

    With the maturation of microfluidic technologies, microchip electrophoresis has been widely employed for amino acid analysis owing to its advantages of low sample consumption, reduced analysis time, high throughput, and potential for integration and automation. In this article, we review the recent progress in amino acid analysis using microchip electrophoresis during the period from 2007 to 2012. Innovations in microchip materials, surface modification, sample introduction, microchip electrophoresis, and detection methods are documented, as well as nascent applications of amino acid analysis in single-cell analysis, microdialysis sampling, food analysis, and extraterrestrial exploration. Without doubt, more applications of microchip electrophoresis in amino acid analysis may be expected soon.

  18. 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. Copyright © 2011 Elsevier B.V. All rights reserved.

  19. Saturn Ring

    NASA Image and Video Library

    2007-12-12

    Like Earth, Saturn has an invisible ring of energetic ions trapped in its magnetic field. This feature is known as a "ring current." This ring current has been imaged with a special camera on Cassini sensitive to energetic neutral atoms. This is a false color map of the intensity of the energetic neutral atoms emitted from the ring current through a processed called charged exchange. In this process a trapped energetic ion steals and electron from cold gas atoms and becomes neutral and escapes the magnetic field. The Cassini Magnetospheric Imaging Instrument's ion and neutral camera records the intensity of the escaping particles, which provides a map of the ring current. In this image, the colors represent the intensity of the neutral emission, which is a reflection of the trapped ions. This "ring" is much farther from Saturn (roughly five times farther) than Saturn's famous icy rings. Red in the image represents the higher intensity of the particles, while blue is less intense. Saturn's ring current had not been mapped before on a global scale, only "snippets" or areas were mapped previously but not in this detail. This instrument allows scientists to produce movies (see PIA10083) that show how this ring changes over time. These movies reveal a dynamic system, which is usually not as uniform as depicted in this image. The ring current is doughnut shaped but in some instances it appears as if someone took a bite out of it. This image was obtained on March 19, 2007, at a latitude of about 54.5 degrees and radial distance 1.5 million kilometres (920,000 miles). Saturn is at the center, and the dotted circles represent the orbits of the moon's Rhea and Titan. The Z axis points parallel to Saturn's spin axis, the X axis points roughly sunward in the sun-spin axis plane, and the Y axis completes the system, pointing roughly toward dusk. The ion and neutral camera's field of view is marked by the white line and accounts for the cut-off of the image on the left. The

  20. 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.

  1. 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.

  2. 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,…

  3. 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,…

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Protein microchips : use for immunoassay and enzymatic reactions.

    SciTech Connect

    Arenkov, P.; Kukhtin, A.; Gemmell, A.; Voloschuk, S.; Chupeeva, V.; Mirzabekov, A.; Biochip Technology Center; Russian Academy of Sciences

    2000-02-15

    Different proteins such as antibodies, antigens, and enzymes were immobilized within the 100 x 100 x 20-{mu}m gel pads of protein microchips. A modified polyacrylamide gel has been developed to accommodate proteins of a size up to 400,000 daltons. Electrophoresis in the microchip reaction chamber speeded up antigen-antibody interactions within the gel. Protein microchips were used in immunoassays for detection of antigens or antibodies, as well as to carry out enzymatic reactions and to measure their kinetics in the absence or presence of an inhibitor. A protein microchip can be used several times in different immunoassays and enzymatic kinetic measurements.

  10. Open channel electrochromatography on a microchip

    SciTech Connect

    Jacobson, S.C.; Hergenroeder, R.; Koutny, L.B.; Ramsey, J.M. )

    1994-07-15

    A glass microchip having a channel with a cross section of 5.6 [mu]m high and 66 [mu]m wide was fabricated using standard photolithographic and etching techniques. The surface of the channel was chemically modified with octadecylsilane to function as the stationary phase for open channel chromatography. Electroosmotic flow was used to [open quotes]load[close quotes] the sample into the microchip and to [open quotes]pump[close quotes] the mobile phase during the experiments. For electric field strengths in the separation column from 27 to 163 V/cm, the linear velocity for the electroosmotic flow ranged from 0.13 to 0.78 mm/s. Detection was performed using direct fluorescence for separation monitoring and indirect fluorescence for void time measurements. Plate heights as low as 4.1 and 5.0 [mu]m were generated for unretained and retained components, respectively. 28 refs., 6 figs., 2 tabs.

  11. Nonlinear mode coupling in a microchip laser

    SciTech Connect

    Lacot, E.; Stoeckel, F.

    1996-09-01

    The dynamics of the total intensity and of each individual mode of a microchip laser have been studied. Because of the nonlinear mode coupling by spatial hole burning, the intensity fluctuation of each longitudinal mode can be described by {ital N} relaxation frequencies, where {ital N} is the number of lasing modes. Owing to the small cross-saturation coefficient between the longitudinal modes, the total intensity exhibits a behavior much more complex than the regular relaxation oscillations usually observed. As a result of the short photon lifetime of the microchip laser this unstable behavior of the total intensity can easily be observed even when the number of modes is small. For each longitudinal mode, we also observed beating and antiphase dynamics between two coupled states of orthogonal polarization. Numerical simulations permit a good description of the experimental results. {copyright} {ital 1996 Optical Society of America.}

  12. 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.

  13. 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).

  14. 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.

  15. Possibility of Microchip Electrophoresis for Biological Application

    NASA Astrophysics Data System (ADS)

    Kataoka, Masatoshi; Kido, Jun-Ichi; Shinohara, Yasuo

    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. Nucleic acid fragments are separated by capillary electrophoresis in a chip with microfabricated channels, with automated detection as well as on-line data evaluation. Microfabricated devices are forecast to be fundamental to the postgenome era, especially in the field of genetics and medicine. However, although there are many reports of the use of these instruments to evaluate standard DNA, DNA ladders, PCR products, and commercially available plasmid digests, little information is available their use with biological material. In this report, we showed the accuracy of sizing and quantification of endonuclease-digested plasmid DNA. We also showed the feasibility of on-microchip endonuclease treatment of plasmid DNA and sequential analysis as an additional application for DNA analysis. Furthermore, to evaluate the possibility of microchip electrophoresis for biological application, the results of the examination of blood sugar in human plasma and mitochondrial membrane potential were shown.

  16. 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

  17. Production, Cost and Chip Characteristics of In-Woods Microchipping

    Treesearch

    J. Thompson; W. Sprinkle

    2013-01-01

    Emerging markets for biomass have increased the interest in producing microchips in the field. As a component of a large United States Department of Energy (DOE) funded project, microchipping has been trialed on a limited scale. The goal of the research was to evaluate the production, cost and chip characteristics of a mobile disc chipper configured to produce...

  18. 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.

  19. 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.

  20. 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.

  1. [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.

  2. 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.

  3. Nematode-Trapping Fungi.

    PubMed

    Jiang, Xiangzhi; Xiang, Meichun; Liu, Xingzhong

    2017-01-01

    Nematode-trapping fungi are a unique and intriguing group of carnivorous microorganisms that can trap and digest nematodes by means of specialized trapping structures. They can develop diverse trapping devices, such as adhesive hyphae, adhesive knobs, adhesive networks, constricting rings, and nonconstricting rings. Nematode-trapping fungi have been found in all regions of the world, from the tropics to Antarctica, from terrestrial to aquatic ecosystems. They play an important ecological role in regulating nematode dynamics in soil. Molecular phylogenetic studies have shown that the majority of nematode-trapping fungi belong to a monophyletic group in the order Orbiliales (Ascomycota). Nematode-trapping fungi serve as an excellent model system for understanding fungal evolution and interaction between fungi and nematodes. With the development of molecular techniques and genome sequencing, their evolutionary origins and divergence, and the mechanisms underlying fungus-nematode interactions have been well studied. In recent decades, an increasing concern about the environmental hazards of using chemical nematicides has led to the application of these biological control agents as a rapidly developing component of crop protection.

  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. Planetary Rings

    NASA Astrophysics Data System (ADS)

    Esposito, Larry

    2014-03-01

    Preface: a personal view of planetary rings; 1. Introduction: the allure of the ringed planets; 2. Studies of planetary rings 1610-2013; 3. Diversity of planetary rings; 4. Individual ring particles and their collisions; 5. Large-scale ring evolution; 6. Moons confine and sculpt rings; 7. Explaining ring phenomena; 8. N-body simulations; 9. Stochastic models; 10. Age and evolution of rings; 11. Saturn's mysterious F ring; 12. Uranus' rings and moons; 13. Neptune's partial rings; 14. Jupiter's ring-moon system after Galileo and New Horizons; 15. Ring photometry; 16. Dusty rings; 17. Concluding remarks; Afterword; Glossary; References; Index.

  8. Readability and histological biocompatibility of microchip transponders in horses.

    PubMed

    Wulf, M; Wohlsein, P; Aurich, J E; Nees, M; Baumgärtner, W; Aurich, C

    2013-10-01

    Identification of horses by microchip transponder is mandatory within the European Union with only a few exceptions. In this study, the readability of such microchips in 428 horses with three different scanners (A, B and C) and the histological changes at the implantation site in 16 animals were assessed. Identification of microchips differed between scanners (P<0.001), and with 'side of neck' (P<0.001). Scanners A, B and C identified 93.5%, 89.7% and 100% of microchips, respectively, on the 'chip-bearing' side of the neck. From the contralateral side, scanners A, B and C identified 21.5%, 26.9% and 89.5% of transponders, respectively. Microchip readability was affected by age (P<0.001), but not by breed of horse. At necropsy, transponders were found in the subcutaneous fat (n=3), inter- or peri-muscular connective tissue (n=8), or musculature (n=5), where they were surrounded by a fibrous capsule ranging in thickness from 12.7 to 289.5 μm in 15 animals. In two animals, immature granulation tissue with attendant granulomatous inflammation, and a granulomatous myositis, surrounding the microchip were identified, respectively. Severe (n=1), moderate (n=1), and mild (n=3) lymphohistiocytic inflammation was noted within the fibrous capsule. Microchip transponders were found to be a highly reliable and biocompatible method of horse identification. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Parallel thermodynamic analysis of duplexes on oligodeoxyribonucleotide microchips.

    SciTech Connect

    Fotin, A. V.; Drobyshev, A. L.; Proudnikov, D. Y.; Perov, A. N.; Mirzabekov, A. D.; Center for Mechanistic Biology and Biotechnology; Engelhardt Inst. of Molecular Biology

    1998-03-15

    A microchip method has been developed for massive and parallel thermodynamic analyses of DNA duplexes. Fluorescently labeled oligonucleotides were hybridized with oligonucleotides immobilized in the 100 x 100 x 20 mum gel pads of the microchips. The equilibrium melting curves for all microchip duplexes were measured in real time in parallel for all microchip duplexes. Thermodynamic data for perfect and mismatched duplexes that were obtained using the microchip method directly correlated with data obtained in solution. Fluorescent labels or longer linkers between the gel and the oligonucleotides appeared to have no significant effect on duplex stability. Extending the immobilized oligonucleotides with a four-base mixture from the 3'-end or one or two universal bases (5-nitroindole) from the 3'- and/or 5'- end increased the stabilities of their duplexes. These extensions were applied to increase the stabilities of the duplexes formed with short oligonucleotides in microchips, to significantly lessen the differences in melting curves of the AT- and GC-rich duplexes, and to improve discrimination of perfect duplexes from those containing poorly recognized terminal mismatches. This study explored a way to increase the efficiency of sequencing by hybridization on oligonucleotide microchips.

  10. 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.

  11. 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.

  12. Microchip device for liquid phase analysis

    SciTech Connect

    Ramsey, j.m.

    2000-05-01

    The lab-on-a-chip concept has enabled miniature instruments to be developed that allow the rapid execution and automation of fluidic operations such as valving, separation, dilution, mixing, and flow splitting upon the proper application of a motive (driving) force. The integration of these simple operations to perform complete, multiple-step chemical assays is rapidly becoming a reality. Such compact, monolithic devices potentially enjoy advantages in speed, cost, automation, reagent consumption, and waste generation compared to existing laboratory-scale instruments. Initial reports of these microfluidic devices focused on combining various electrokinetically driven separation methods including microchip electrophoresis, gel electrophoresis, micellar electrokinetic chromatography (MEKC) and open channel electrochromatography (OCEC) with fluidic valving to introduce sample plugs into the separation channel. Other operations have quickly been integrated with the separations and fluidic valving on these microchips. For example, integrated devices with mixers/diluters for precolumn and postcolumn analyte derivatization, deoxyribonucleic acid (DNA) restriction digests, enzyme assays, and polymerase chain reaction (PCR) amplification have been added to the basic design. Integrated mixers that can perform solvent programming for both MEKC and OCEC have also been demonstrated. These examples are simple, yet powerful, demonstrations of the potential for lab-on-a-chip devices. In this report, three key areas for improved performance of these devices are described: on-chip calibration techniques, enhanced separative performance, and enhanced detection capabilities.

  13. 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.

  14. 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.

  15. 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.

  16. Variable-temperature rate coefficients of proton-transfer equilibrium reaction C2H4 + H3O+ ⇄ C2H5+ + H2O measured with a coaxial molecular beam radio frequency ring electrode ion trap.

    PubMed

    Smith, Mark A; Yuan, Bing; Sanov, Andrei

    2012-11-29

    The rate coefficients for the forward and reverse proton-transfer reactions C(2)H(4) + H(3)O(+) ⇄ C(2)H(5)(+) + H(2)O are studied with respect to independent varied neutral molecule and ion temperatures. The measurements are performed using a coaxial molecular beam radio frequency ring electrode ion trap at trap temperatures down to 23 K and beam temperatures up to 450 K. The temperature-dependent rate coefficients suggest that in this temperature window, the reaction proceeds through a statistically equilibrated complex. In order to explain the observed rate coefficients, a new type of reaction temperature was defined in these studies that considered collisional and internal (rotational and vibrational) degrees of freedom of both H(3)O(+) and C(2)H(4). The enthalpy and entropy of the equilibrium reaction deduced from a Van't Hoff plot are ΔH = (5.1 ± 0.5) kJ·mol(-1) and ΔS = (-15.0 ± 0.9) J·mol(-1)·K(-1), respectively.

  17. Extending dark optical trapping geometries.

    PubMed

    Arnold, Aidan S

    2012-07-01

    New counterpropagating geometries are presented for localizing ultracold atoms in the dark regions created by the interference of Laguerre-Gaussian laser beams. In particular dark helices, an "optical revolver," axial lattices of rings, and axial lattices of ring lattices of rings are considered and a realistic scheme for achieving phase stability is explored. The dark nature of these traps will enable their use as versatile tools for low-decoherence atom interferometry with zero differential light shifts.

  18. Planetary Rings

    NASA Astrophysics Data System (ADS)

    Esposito, Larry W.

    2011-07-01

    Preface; 1. Introduction: the allure of ringed planets; 2. Studies of planetary rings 1610-2004; 3. Diversity of planetary rings; 4. Individual ring particles and their collisions; 5. Large-scale ring evolution; 6. Moons confine and sculpt rings; 7. Explaining ring phenomena; 8. N-Body simulations; 9. Stochastic models; 10. Age and evolution of rings; 11. Saturn's mysterious F ring; 12. Neptune's partial rings; 13. Jupiter's ring-moon system after Galileo; 14. Ring photometry; 15. Dusty rings; 16. Cassini observations; 17. Summary: the big questions; Glossary; References; Index.

  19. 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.

  20. 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.

  1. Granulomatous Inflammatory Response to a Microchip Implanted in a Dog for Eight Years.

    PubMed

    Legallet, Claire; Mankin, Kelley Thieman; Spaulding, Kathy; Mansell, Joanne

    An 8 yr old neutered male springer spaniel dog was referred to Texas A&M University, College of Veterinary Medicine for a large, firm, fixed mass, located in the dorsal cervical tissue. The dog was otherwise healthy and had undergone microchip implantation approximately 8 yr prior. Radiographs, ultrasound, and microchip scanner confirmed the presence of a microchip within the mass. The microchip and associated mass were surgically excised, and histopathologic examination revealed granulomatous inflammation surrounding a cracked microchip. This case represents the first report of a granulomatous inflammatory response to a microchip 8 yr after implantation in a dog and highlights an important differential diagnosis.

  2. 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

  3. 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.

  4. 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

  5. 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.

  6. Microchip atmospheric pressure chemical ionization source for mass spectrometry.

    PubMed

    Ostman, Pekka; Marttila, Seppo J; Kotiaho, Tapio; Franssila, Sami; Kostiainen, Risto

    2004-11-15

    A novel microchip heated nebulizer for atmospheric pressure chemical ionization mass spectrometry is presented. Anisotropic wet etching is used to fabricate the flow channels, inlet, and nozzle on a silicon wafer. An integrated heater of aluminum is sputtered on a glass wafer. The two wafers are jointed by anodic bonding, creating a two-dimensional version of an APCI source with a sample channel in the middle and gas channels symmetrically on both sides. The ionization is initiated with an external corona-discharge needle positioned 2 mm in front of the microchip heated nebulizer. The microchip APCI source provides flow rates down to 50 nL/min, stable long-term analysis with chip lifetime of weeks, good quantitative repeatability (RSD < 10%) and linearity (r(2) > 0.995) with linear dynamic rage of at least 4 orders of magnitude, and cost-efficient manufacturing. The limit of detection (LOD) for acridine measured with microchip APCI at flow rate of 6.2 muL/min was 5 nM, corresponding to a mass flow of 0.52 fmol/s. The LOD with commercial macro-APCI at a flow rate of 1 mL/min for acridine was the same, 5 nM, corresponding to a significantly worse mass flow sensitivity (83 fmol/s) than measured with microchip APCI. The advantages of microchip APCI makes it a very attractive new microfluidic detector.

  7. 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.

  8. 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.

  9. Generation of modulated microchip laser pulses

    NASA Astrophysics Data System (ADS)

    Almabouada, F.; Aiadi, K. E.; Louhibi, D.

    2015-01-01

    Modulated 532 nm laser pulses were generated by a Nd:YVO4 microchip laser and a KTP crystal end-pumped by a 808 nm laser diode. The interest in such works arise from the efficiency of this type of laser in several applications. To obtain the desired type of the modulated laser pulses, the electrical circuit of the laser diode was designed so as to enable varying their driving signal and current values. Different modulated signals were used, such as square wave, sine wave, and burst mode pulses. Varying the peak drive current, the duty cycle, and the number of pulses allowed us to adjust the laser energy. For the burst mode experiment, the pulse energy obtained was about 1.2 μJ.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Problems Associated with the Microchip Data of Stray Dogs and Cats Entering RSPCA Queensland Shelters

    PubMed Central

    Lancaster, Emily; Rand, Jacquie; Collecott, Sheila; Paterson, Mandy

    2015-01-01

    Simple Summary Microchip identification has become an important tool to reunite stray dogs and cats with their owners, and is now compulsory in most states of Australia. Improvement of the microchipping system in Australia is limited by a lack of published Australian data documenting the problems experienced by shelter staff when using microchip data to contact the owner of a stray animal. In this study we determine the character and frequency of inaccurate microchip data to identify weaknesses in the current microchipping system. This information could be used to develop strategies that increase the accuracy of microchip data that will increase the reclaiming of stray animals. Abstract A lack of published information documenting problems with the microchip data for the reclaiming of stray animals entering Australian shelters limits improvement of the current microchipping system. A retrospective study analysing admission data for stray, adult dogs (n = 7258) and cats (n = 6950) entering the Royal Society for the Prevention of Cruelty to Animals (RSPCA) Queensland between January 2012 and December 2013 was undertaken to determine the character and frequency of microchip data problems and their impact on outcome for the animal. Only 28% of dogs and 9% of cats were microchipped, and a substantial proportion (37%) had problems with their data, including being registered to a previous owner or organisation (47%), all phone numbers incorrect/disconnected (29%), and the microchip not registered (14%). A higher proportion of owners could be contacted when the microchip had no problems, compared to those with problems (dogs, 93% vs. 70%; cats, 75% vs. 41%). The proportion of animals reclaimed declined significantly between microchipped animals with no data problems, microchipped animals with data problems and non-microchipped animals—87%, 69%, and 37%, respectively, for dogs and 61%, 33%, and 5%, respectively, for cats. Strategies are needed to increase the accuracy of

  16. 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.

  17. 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.

  18. Microchips for CE: breakthroughs in real-world food analysis.

    PubMed

    Escarpa, Alberto; González, María Cristina; López Gil, Miguel Angel; Crevillén, Agustín G; Hervás, Miriam; García, Miguel

    2008-12-01

    The well-known complexity of food matrices is approached using CE microchips with different strategies to improve the selectivity and sensitivity of the analysis by avoiding and/or making the sample preparation as simple as possible: (i) enhancing the peak capacity in order to perform direct injection, (ii) using the microchip platform to measure one target analyte/group of analytes with or without separating other related interferences, (iii) integrating sample preparation steps on the microchip platform, and (iv) integrating new analytical tools from nanotechnology in the detection stage. New analyte separations of food significance involving DNA probes, biogenic amines, vanilla flavors, and dyes have been reported as successfully breaking new barriers in areas of high impact in the market, such as transgenic food analysis, as well as the detection of frauds and toxins. Simple microchip layouts are still the most common designs used, though sophisticated new ones are emerging. In contrast to other application areas, electrochemical detection continues to be the most common detection route, followed by LIF, though non-conventional detection routes are also emerging, such as chemiluminescence or UV. In terms of analytical performance, the integration of calibration and quality control on a microchip platform, and remarkable accuracy and precision are being obtained using creative analytical methodologies that enhance the analytical potency of microfluidic chips for their future commercialization. This review critically states the most important advances derived from work done in the field over the past 2-3 years.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. Organically modified sols as pseudostationary phases for microchip electrophoresis.

    PubMed

    Pumera, Martin; Wang, Joseph; Grushka, Eli; Lev, Ovadia

    2007-04-30

    We demonstrate that the selectivity of microchip electrophoresis separations is greatly improved by the presence of organically modified silica (Ormosil) sols in the run buffer. A negatively-charged N-(trimethoxysilylpropyl)ethylenediamine triacetic-acid (TETT)-based sol is used for improving the selectivity between nitroaromatic explosives and a methyltrimethoxysilane (MTMOS)-based sol is employed for enhancing the microchip separation of environmental pollutants, aminophenols. These sols are added to the run buffer and act as pseudostationary phases. Their presence in the run buffer changes the apparent mobility of studied solutes, and leads to a higher resolution. The observed mobilities changes reflect the interactions between the Ormosil sols and the solutes. Relevant experimental variables have been characterized and optimized. The diverse chemistry of Ormosil sols should be extremely useful for tailoring the selectivity of a wide range of electrophoresis microchip separations.

  6. Analysis of Anions in Ambient Aerosols by Microchip Capillary Electrophoresis

    SciTech Connect

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

    2006-10-01

    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 µM) and low limits-of-detection for sulfate and nitrate with Au providing the lowest detection limits (1 µM) 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.

  7. 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.

  8. 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.

  9. MicroChip Imager Module for Recognition of Microorganisms

    SciTech Connect

    Alferov, Oleg

    2001-01-01

    The MicroChip Reader for Cereus Group takes the table of intensities of hybridization signals produced by the MicroChip Imager software and evokes a series of steps designed to recognize the pattern of intensities specific to a particular Cereus subgroup. Seven subgroups of the Cereus group can be identified by particular features of their RNA sequence. The Reader also provides statistics documenting how well its conclusion is confirmed by the hybridization signals. At the user’s request, the Reader can list every recognition step utilized so that the user can verify the recognition process manually if desired.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. 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

  16. 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.

  17. 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.

  18. Longevity of radiofrequency identification device microchips in citrus trees

    USDA-ARS?s Scientific Manuscript database

    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...

  19. 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.

  20. 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.

  1. 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.

  2. A microchip laser with intracavity second-harmonic generation

    SciTech Connect

    Derzhavin, S I; Mashkovskii, D A; Timoshkin, V N

    2008-12-31

    A short-pulse 'green' 532-nm Nd{sup 3+}:YVO{sub 4} and KTiOPO{sub 4} microchip laser with intracavity second-harmonic generation, which is pumped by a 809-nm semiconductor laser diode, is developed. (lasers. amplifiers)

  3. 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.

  4. 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.

  5. 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

  6. Problems Associated with the Microchip Data of Stray Dogs and Cats Entering RSPCA Queensland Shelters.

    PubMed

    Lancaster, Emily; Rand, Jacquie; Collecott, Sheila; Paterson, Mandy

    2015-05-13

    A lack of published information documenting problems with the microchip data for the reclaiming of stray animals entering Australian shelters limits improvement of the current microchipping system. A retrospective study analysing admission data for stray, adult dogs (n = 7258) and cats (n = 6950) entering the Royal Society for the Prevention of Cruelty to Animals (RSPCA) Queensland between January 2012 and December 2013 was undertaken to determine the character and frequency of microchip data problems and their impact on outcome for the animal. Only 28% of dogs and 9% of cats were microchipped, and a substantial proportion (37%) had problems with their data, including being registered to a previous owner or organisation (47%), all phone numbers incorrect/disconnected (29%), and the microchip not registered (14%). A higher proportion of owners could be contacted when the microchip had no problems, compared to those with problems (dogs, 93% vs. 70%; cats, 75% vs. 41%). The proportion of animals reclaimed declined significantly between microchipped animals with no data problems, microchipped animals with data problems and non-microchipped animals-87%, 69%, and 37%, respectively, for dogs and 61%, 33%, and 5%, respectively, for cats. Strategies are needed to increase the accuracy of microchip data to facilitate the reclaiming of stray dogs and cats.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. Ring World

    NASA Image and Video Library

    2007-03-01

    Our robotic emissary, flying high above Saturn, captured this view of an alien copper-colored ring world. The overexposed planet has deliberately been removed to show the unlit rings alone, seen from an elevation of 60 degrees

  15. Neptune Rings

    NASA Image and Video Library

    1999-10-29

    This 591-second exposure of the rings of Neptune were taken with the clear filter by NASA Voyager 2 wide-angle camera. The two main rings are clearly visible and appear complete over the region imaged.

  16. Ring Backdrop

    NASA Image and Video Library

    2011-01-03

    Saturn moon Enceladus brightly reflects sunlight before a backdrop of the planet rings and the rings shadows cast onto the planet. NASA Cassini spacecraft captured this snapshot during its flyby of the moon on Nov. 30, 2010.

  17. 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.

  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.

    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. 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.

  20. 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.

  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. Microchip-based electrochemical detection for monitoring cellular systems

    PubMed Central

    Johnson, Alicia S.; Selimovic, Asmira; Martin, R. Scott

    2013-01-01

    The use of microchip devices to study cellular systems is a rapidly growing research area. There are numerous advantages of using on-chip integrated electrodes to monitor various cellular processes. The purpose of this review article is to give examples of advancements in microchip-based cellular analysis, specifically where electrochemistry is used for the detection scheme. These examples include on-chip detection of single cell quantal exocytosis, electrochemical analysis of intracellular contents, the ability to integrate cell culture/immobilization with electrochemistry, and the use of integrated electrodes to ensure cell confluency in longer term cell culture experiments. A perspective on future trends in this area is also given. PMID:23340999

  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. Diode edge-pumped passively Q-switched microchip laser

    NASA Astrophysics Data System (ADS)

    Kong, Weipeng; Tsunekane, Masaki; Taira, Takunori

    2015-09-01

    There is an increasing demand for high-intensity subnanosecond lasers for emerging industrial applications. While femtosecond and picosecond laser sources are considered promising, they suffer from the significant drawbacks of increased complexity and cost. In this regard, we demonstrate a unique edge-pumped passively Q-switched Nd∶YAG/Cr4+∶YAG microchip laser. The microchip is made of a Nd∶YAG/Sm∶YAG composite ceramic, and a Sm∶YAG cladding is utilized as both the pump beam waveguide and amplified spontaneous emission absorber. With the use of a flat-concave laser cavity, we obtain single-pulse energy of 1.66 mJ for an absorbed pump energy of 24 mJ. Further, the resulting pulse width is 683 ps, and the repetition rate is 10 Hz.

  7. 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

  8. 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.

  9. 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.

  10. Maskless Electron-Beam Lithography for Trusted Microchip Production

    DTIC Science & Technology

    2016-03-31

    lithography has soared and continues to rise unabated. Multibeam has developed maskless electron-beam lithography ( EBL ) for producing advanced Rad-Hard...and other DoD microchips at lower cost. In addition to significant cost savings in mask and lithography equipment, Multibeam’s maskless EBL technology...maskless electron-beam lithography ( EBL ); e-beam direct write (EBDW); complementary e-beam lithography (CEBL); multiple patterning; cycle time

  11. 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.

  12. Large linewidth-enhancement factor in a microchip laser

    SciTech Connect

    Szwaj, Christophe; Lacot, Eric; Hugon, Olivier

    2004-09-01

    We evidence experimentally that the linewidth-enhancement factor {alpha} can take a rather large value ({alpha}{approx_equal}1) for a nonsemiconductor laser, here a Nd{sup 3+}: YAG microchip laser. This measure is performed using an original and simple method adapted to this kind of laser and based on the variations of the laser relaxation frequency when the laser is subjected to an optical feedback.

  13. Continuous two-wave lasing in microchip Nd : YAG lasers

    SciTech Connect

    Ievlev, Ivan V; Koryukin, Igor' V; Lebedeva, Yu S; Khandokhin, Pavel A

    2011-08-31

    Simultaneous two-wave lasing was obtained in microchip end-pumped Nd:YAG lasers at the wavelengths of 1061.5 and 1064.17 nm at room temperature. Laser wave intensities were studied as functions of crystal temperature and pump power. The ranges of parameters were determined in which the two-wave lasing occurs and the reasons for such lasing were established. A model is suggested, which adequately describes the experimental results obtained. (control of radiation parameters)

  14. Gene regulation by substoichiometric heterocomplex formation of undecameric TRAP and trimeric anti-TRAP.

    PubMed

    Ihms, Elihu C; Zhou, Mowei; Zhang, Yun; Kleckner, Ian R; McElroy, Craig A; Wysocki, Vicki H; Gollnick, Paul; Foster, Mark P

    2014-03-04

    The control of tryptophan production in Bacillus is a paradigmatic example of gene regulation involving the interplay of multiple protein and nucleic acid components. Central to this combinatorial mechanism are the homo-oligomeric proteins TRAP (trp RNA-binding attenuation protein) and anti-TRAP (AT). TRAP forms undecameric rings, and AT assembles into triskelion-shaped trimers. Upon activation by tryptophan, the outer circumference of the TRAP ring binds specifically to a series of tandem sequences present in the 5' UTR of RNA transcripts encoding several tryptophan metabolism genes, leading to their silencing. AT, whose expression is up-regulated upon tryptophan depletion to concentrations not exceeding a ratio of one AT trimer per TRAP 11-mer, restores tryptophan production by binding activated TRAP and preventing RNA binding. How the smaller AT inhibitor prevents RNA binding at such low stoichiometries has remained a puzzle, in part because of the large RNA-binding surface on the tryptophan-activated TRAP ring and its high affinity for RNA. Using X-ray scattering, hydrodynamic, and mass spectrometric data, we show that the polydentate action of AT trimers can condense multiple intact TRAP rings into large heterocomplexes, effectively reducing the available contiguous RNA-binding surfaces. This finding reveals an unprecedented mechanism for substoichiometric inhibition of a gene-regulatory protein, which may be a widespread but underappreciated regulatory mechanism in pathways that involve homo-oligomeric or polyvalent components.

  15. Gene regulation by substoichiometric heterocomplex formation of undecameric TRAP and trimeric anti-TRAP

    PubMed Central

    Ihms, Elihu C.; Zhou, Mowei; Zhang, Yun; Kleckner, Ian R.; McElroy, Craig A.; Wysocki, Vicki H.; Gollnick, Paul; Foster, Mark P.

    2014-01-01

    The control of tryptophan production in Bacillus is a paradigmatic example of gene regulation involving the interplay of multiple protein and nucleic acid components. Central to this combinatorial mechanism are the homo-oligomeric proteins TRAP (trp RNA-binding attenuation protein) and anti-TRAP (AT). TRAP forms undecameric rings, and AT assembles into triskelion-shaped trimers. Upon activation by tryptophan, the outer circumference of the TRAP ring binds specifically to a series of tandem sequences present in the 5′ UTR of RNA transcripts encoding several tryptophan metabolism genes, leading to their silencing. AT, whose expression is up-regulated upon tryptophan depletion to concentrations not exceeding a ratio of one AT trimer per TRAP 11-mer, restores tryptophan production by binding activated TRAP and preventing RNA binding. How the smaller AT inhibitor prevents RNA binding at such low stoichiometries has remained a puzzle, in part because of the large RNA-binding surface on the tryptophan-activated TRAP ring and its high affinity for RNA. Using X-ray scattering, hydrodynamic, and mass spectrometric data, we show that the polydentate action of AT trimers can condense multiple intact TRAP rings into large heterocomplexes, effectively reducing the available contiguous RNA-binding surfaces. This finding reveals an unprecedented mechanism for substoichiometric inhibition of a gene-regulatory protein, which may be a widespread but underappreciated regulatory mechanism in pathways that involve homo-oligomeric or polyvalent components. PMID:24550461

  16. Microchip-based human serum atherogenic lipoprotein profile analysis.

    PubMed

    Wang, Hua; Zhang, Wei; Wan, Jun; Liu, Weiwei; Yu, Bo; Jin, Qinghui; Guan, Ming

    2014-12-15

    Owing to the mounting evidence of serum lipid changes in atherosclerosis, there has been increasing interest in developing new methods for analyzing atherogenic lipoprotein profiles. The separation of lipoprotein and lipoprotein subclasses has been demonstrated using a microchip capillary electrophoresis (CE) system [Chromatographia 74 (2011) 799-805]. In contrast to this previous study, the current report demonstrates that sdLDL peak efficiencies can be improved dramatically by adding gold nanoparticles (AuNPs) to the sample. Moreover, NBD C6-ceramide was identified as a satisfactory dye for specific labeling and quantitation of individual serum lipoproteins. The accuracy of the method was evaluated by comparison with ultracentrifuge separated small, dense, low-density lipoprotein (sdLDL). A high correlation was observed between these two methods for sdLDL cholesterol. Lipid levels were investigated between atherosclerotic patients and healthy controls. The variation of serum atherogenic lipoprotein profiles for atherosclerotic patients pre- and post-treatment was assessed by microchip CE. This method has potential for the rapid and sensitive detection of different lipoprotein classes as well as their subclasses and, therefore, is suitable for routine clinical applications. Microchip-based atherogenic lipoprotein profile assays will greatly improve the analysis of risk factors in atherosclerosis and will provide useful information for monitoring the effect of therapies on atherosclerotic disease. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Precolumn reactions with electrophoretic analysis integrated on a microchip

    SciTech Connect

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

    1994-12-01

    A glass microchip was constructed to perform chemical reactions and capillary electrophoresis sequentially. The channel manifold on the glass substrate was fabricated using standard photolithographic, etching, and deposition techniques. The microchip has a reaction chamber with a 1 nL reaction volume and a separation column with a 15.4 mm separation length. Electrical control of the buffer, analyte, and reagent streams made possible the precise manipulation of the fluids within the channel manifold. The microchip was operated under a continuous reaction mode with gated injections to introduce the reaction product onto the separation column with high reproducibility (<1.8% rsd in peak area). The reaction and separation performances were evaluated by reacting amino acids with o-phthaldialdehyde to generate a fluorescent product which was detected by laser-induced fluorescence. Control of the reaction and separation conditions was sufficient to measure reaction kinetics and variation of detection limits with reaction time. Half-times of reaction of 5.1 and 6.2 s and detection limits of 0.55 and 0.83 fmol were measured for arginine and glycine, respectively. 18 refs., 10 figs.

  18. Food analysis on microchip electrophoresis: an updated review.

    PubMed

    Martín, Aida; Vilela, Diana; Escarpa, Alberto

    2012-08-01

    From 2008 to date, basically, single-cross microchip electrophoresis (ME) design has been used for food analysis with electrochemical and laser-induced fluorescence detection being the most common principles coupled. In the last 4 years, the main outlines were: (i) the exploration of new analytes such as heavy metals, nitrite, micotoxins, microorganisms, and allergens; (ii) the development of electrokinetic microfluidic (bio-) sensors into microchip format for the detection of toxins; and interestingly (iii) although sample preparation is still performed off-chip, an important increase in works dealing with complicated food samples has been clearly noticed. Although microchip technology based on electrokinetics is emerging from important fields such as authentication of foods, detection of frauds, toxics, and allergens; the marriage between micro- and nanotechnologies and total integration approaches has not reached the expected impact in the field but it is still a great promise for the development of ME of new generations for food analysis. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. [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.

  4. 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.

  5. 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

  6. Planetary Rings

    NASA Astrophysics Data System (ADS)

    Tiscareno, Matthew S.

    Planetary rings are the only nearby astrophysical disks and the only disks that have been investigated by spacecraft (especially the Cassini spacecraft orbiting Saturn). Although there are significant differences between rings and other disks, chiefly the large planet/ring mass ratio that greatly enhances the flatness of rings (aspect ratios as small as 10- 7), understanding of disks in general can be enhanced by understanding the dynamical processes observed at close range and in real time in planetary rings.We review the known ring systems of the four giant planets, as well as the prospects for ring systems yet to be discovered. We then review planetary rings by type. The A, B, and C rings of Saturn, plus the Cassini Division, comprise our solar system's only dense broad disk and host many phenomena of general application to disks including spiral waves, gap formation, self-gravity wakes, viscous overstability and normal modes, impact clouds, and orbital evolution of embedded moons. Dense narrow rings are found both at Uranus (where they comprise the main rings entirely) and at Saturn (where they are embedded in the broad disk) and are the primary natural laboratory for understanding shepherding and self-stability. Narrow dusty rings, likely generated by embedded source bodies, are surprisingly found to sport azimuthally confined arcs at Neptune, Saturn, and Jupiter. Finally, every known ring system includes a substantial component of diffuse dusty rings.Planetary rings have shown themselves to be useful as detectors of planetary processes around them, including the planetary magnetic field and interplanetary impactors as well as the gravity of nearby perturbing moons. Experimental rings science has made great progress in recent decades, especially numerical simulations of self-gravity wakes and other processes but also laboratory investigations of coefficient of restitution and spectroscopic ground truth. The age of self-sustained ring systems is a matter of

  7. 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.

  8. Yb:KYW microchip laser with self-frequency Raman conversion

    SciTech Connect

    Grabtchikov, A S; Kuzmin, A N; Lisinetskii, V A; Orlovich, V A; Voitovich, A P; Demidovich, A A; Eichler, H J; Titov, A N

    2003-02-28

    Passively Q-switched and cw operation regimes of a diode-pumped Yb:KYW microchip laser have been investigated. The maximum slope efficiency for cw operation of 23% relative to incident pump power has been achieved. Self-frequency Raman conversion for microchip cavity configuration has been realised. (lasers)

  9. Microchip Module for Blood Sample Preparation and Nucleic Acid Amplification Reactions

    PubMed Central

    Yuen, Po Ki; Kricka, Larry J.; Fortina, Paolo; Panaro, Nicholas J.; Sakazume, Taku; Wilding, Peter

    2001-01-01

    A computer numerical control-machined plexiglas-based microchip module was designed and constructed for the integration of blood sample preparation and nucleic acid amplification reactions. The microchip module is comprised of a custom-made heater-cooler for thermal cycling, a series of 254 μm × 254 μm microchannels for transporting human whole blood and reagents in and out of an 8–9 μL dual-purpose (cell isolation and PCR) glass-silicon microchip. White blood cells were first isolated from a small volume of human whole blood (<3 μL) in an integrated cell isolation–PCR microchip containing a series of 3.5-μm feature-sized “weir-type” filters, formed by an etched silicon dam spanning the flow chamber. A genomic target, a region in the human coagulation Factor V gene (226-bp), was subsequently directly amplified by microchip-based PCR on DNA released from white blood cells isolated on the filter section of the microchip mounted onto the microchip module. The microchip module provides a convenient means to simplify nucleic acid analyses by integrating two key steps in genetic testing procedures, cell isolation and PCR and promises to be adaptable for additional types of integrated assays. PMID:11230164

  10. Microchip module for blood sample preparation and nucleic acid amplification reactions.

    PubMed

    Yuen, P K; Kricka, L J; Fortina, P; Panaro, N J; Sakazume, T; Wilding, P

    2001-03-01

    A computer numerical control-machined plexiglas-based microchip module was designed and constructed for the integration of blood sample preparation and nucleic acid amplification reactions. The microchip module is comprised of a custom-made heater-cooler for thermal cycling, a series of 254 microm x 254 microm microchannels for transporting human whole blood and reagents in and out of an 8--9 microL dual-purpose (cell isolation and PCR) glass-silicon microchip. White blood cells were first isolated from a small volume of human whole blood (<3 microL) in an integrated cell isolation--PCR microchip containing a series of 3.5-microm feature-sized "weir-type" filters, formed by an etched silicon dam spanning the flow chamber. A genomic target, a region in the human coagulation Factor V gene (226-bp), was subsequently directly amplified by microchip-based PCR on DNA released from white blood cells isolated on the filter section of the microchip mounted onto the microchip module. The microchip module provides a convenient means to simplify nucleic acid analyses by integrating two key steps in genetic testing procedures, cell isolation and PCR and promises to be adaptable for additional types of integrated assays.

  11. 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.

  12. 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.

  13. 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

  14. Translucent Rings

    NASA Image and Video Library

    2014-12-08

    Although solid-looking in many images, Saturn's rings are actually translucent. In this picture, we can glimpse the shadow of the rings on the planet through (and below) the A and C rings themselves, towards the lower right hand corner. For centuries people have studied Saturn's rings, but questions about the structure and composition of the rings lingered. It was only in 1857 when the physicist James Clerk Maxwell demonstrated that the rings must be composed of many small particles and not solid rings around the planet, and not until the 1970s that spectroscopic evidence definitively showed that the rings are composed mostly of water ice. This view looks toward the sunlit side of the rings from about 17 degrees above the ringplane. The image was taken with the Cassini spacecraft wide-angle camera on Aug. 12, 2014 in near-infrared light centered at 752 nanometers. The view was obtained at a distance of approximately 1.4 million miles (2.3 million kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 24 degrees. Image scale is 85 miles (136 kilometers) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA18295

  15. 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.

  16. 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.

  17. 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.

  18. Ripple Trap

    NASA Technical Reports Server (NTRS)

    2006-01-01

    3 April 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the margin of a lava flow on a cratered plain in the Athabasca Vallis region of Mars. Remarkably, the cratered plain in this scene is essentially free of bright, windblown ripples. Conversely, the lava flow apparently acted as a trap for windblown materials, illustrated by the presence of the light-toned, wave-like texture over much of the flow. That the lava flow surface trapped windblown sand and granules better than the cratered plain indicates that the flow surface has a rougher texture at a scale too small to resolve in this image.

    Location near: 10.7oN, 204.5oW Image width: 3 km (1.9 mi) Illumination from: lower left Season: Northern Winter

  19. Widening Rings

    NASA Image and Video Library

    2010-03-18

    Saturn rings and its moon Rhea are imaged before a crescent of the planet in this image captured by NASA Cassini spacecraft. The shadows of the rings continue to grow wider after their disappearing act during the planet August 2009 equinox.

  20. 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

  1. Ring Slicer

    NASA Image and Video Library

    2015-07-06

    Saturn's moon Prometheus, seen here looking suspiciously blade-like, is captured near some of its sculpting in the F ring. Prometheus' (53 miles or 86 kilometers across) orbit sometimes takes it into the F ring. When it enters the ring, it leaves a gore where its gravitational influence clears out some of the smaller ring particles. Below Prometheus, the dark lanes interior to the F ring's bright core provide examples of previous ring-moon interactions. This view looks toward the unilluminated side of the rings from about 7 degrees below the ring plane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on March 15, 2015. The view was obtained at a distance of approximately 286,000 miles (461,000 kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 115 degrees. Image scale is 1.7 miles (2.8 kilometers) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA18324

  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. 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.

  4. Novel electrostatic trap for cold polar molecules

    NASA Astrophysics Data System (ADS)

    Xu, Xue-Yan; Ma, Hui; Yin, Jian-Ping

    2007-12-01

    We propose a novel scheme in which cold polar molecules are trapped by an electrostatic field generated by the combination of a pair of parallel transparent electrodes (i.e., two infinite transparent plates) and a ring electrode (i.e., a ring wire). The spatial distributions of the electrostatic fields from the above charged wire and the charged plates and the corresponding Stark potentials for cold CO molecules are calculated; the dependences of the trap centre position on the geometric parameters of the electrode are analysed. We also discuss the loading process of cold molecules from a cold molecular beam into our trap. This study shows that the proposed scheme is not only simple and convenient to trap, manipulate and control cold polar molecules in weak-field-seeking states, but also provides an opportunity to study cold collisions and collective quantum effects in a variety of cold molecular systems, etc.

  5. A visual multiplex PCR microchip with easy sample loading.

    PubMed

    Chen, Jian-Wei; Shao, Ning; Zhang, Yuchen; Zhu, Yuanshou; Yang, Litao; Tao, Sheng-Ce

    2017-06-20

    There is an urgent demand for affordable, rapid and easy-to-use technology to simultaneously detect many different DNA targets within one reaction. Conventional multiplex PCR is an effective methodology to simultaneously amplify different DNA targets. However, its multiplicity is limited due to the intrinsic interference and competition among primer pairs within one tube. Here, we present an easy multiplex PCR microchip system, which can simultaneously detect 54 targets. The design of the microchip is quite simple. There is a microchannel connected with multiple underlying parallel microwells. And every microchannel has an inlet/outlet for loading PCRmix. The surface of the microchannel is hydrophobic and the inner surface of the microwell is hydrophilic, which enables us to load and separate the PCRmix into different microwells simultaneously. Different primer pairs and low melting agarose are pre-fixed in different microwells, and the microchip is assembled with top glass. The PCRmix is loaded into inlets and then mineral oil is sequentially pipetted into channels to push the PCRmix into all microwells and subsequently mineral oil fills the channels to avoid cross contaminations. After the PCRmix is loaded, it would be placed on a plat thermal cycler for PCR. During PCR, the low melting gel in the well is liquid and after PCR it would be solidified due to temperature changes. When PCR is completed, a nucleic acid dye is introduced into channels and then results are visualized by a home-made, potable UV detector. In our platform we successfully detected seven frequently used targets of genetically modified (GM) organisms. The results demonstrate that our platform has high flexibility and specificity. Due to the excellent performance of this technology, we believe that it can be applied to multiple nucleic acid detection fields including GM organisms.

  6. Observation of transverse patterns in an isotropic microchip laser

    SciTech Connect

    Chen, Y.F.; Lan, Y.P.

    2003-04-01

    An isotropic microchip laser is used to study the characteristics of high-order wave functions in a two-dimensional (2D) quantum harmonic oscillator based on the identical functional forms. With a doughnut pump profile, the spontaneous transverse modes are found to, generally, be elliptic and hyperbolic transverse modes. Theoretical analyses reveal that the elliptic transverse modes are analogous to the coherent states of a 2D harmonic oscillator; the formation of hyperbolic transverse modes is a spontaneous mode locking between two identical Hermite-Gaussian modes.

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. 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. Copyright © 2011 Elsevier Ltd. All rights reserved.

  12. DNA analysis using an integrated microchip for multiplex PCR amplification and electrophoresis for reference samples.

    PubMed

    Le Roux, Delphine; Root, Brian E; Reedy, Carmen R; Hickey, Jeffrey A; Scott, Orion N; Bienvenue, Joan M; Landers, James P; Chassagne, Luc; de Mazancourt, Philippe

    2014-08-19

    A system that automatically performs the PCR amplification and microchip electrophoretic (ME) separation for rapid forensic short tandem repeat (STR) forensic profiling in a single disposable plastic chip is demonstrated. The microchip subassays were optimized to deliver results comparable to conventional benchtop methods. The microchip process was accomplished in sub-90 min compared with >2.5 h for the conventional approach. An infrared laser with a noncontact temperature sensing system was optimized for a 45 min PCR compared with the conventional 90 min amplification time. The separation conditions were optimized using LPA-co-dihexylacrylamide block copolymers specifically designed for microchip separations to achieve accurate DNA size calling in an effective length of 7 cm in a plastic microchip. This effective separation length is less than half of other reports for integrated STR analysis and allows a compact, inexpensive microchip design. This separation quality was maintained when integrated with microchip PCR. Thirty samples were analyzed conventionally and then compared with data generated by the microfluidic chip system. The microfluidic system allele calling was 100% concordant with the conventional process. This study also investigated allelic ladder consistency over time. The PCR-ME genetic profiles were analyzed using binning palettes generated from two sets of allelic ladders run three and six months apart. Using these binning palettes, no allele calling errors were detected in the 30 samples demonstrating that a microfluidic platform can be highly consistent over long periods of time.

  13. A clinical trial for therapeutic drug monitoring using microchip-based fluorescence polarization immunoassay.

    PubMed

    Tachi, Tomoya; Hase, Tetsunari; Okamoto, Yukihiro; Kaji, Noritada; Arima, Takeshi; Matsumoto, Hiroyuki; Kondo, Masashi; Tokeshi, Manabu; Hasegawa, Yoshinori; Baba, Yoshinobu

    2011-10-01

    Microchip analysis is a promising method for therapeutic drug monitoring. This led us to evaluate a microchip-based fluorescence polarization immunoassay (FPIA) system for point-of-care testing on patients being treated with theophylline. The sera were collected from 20 patients being treated with theophylline. Fluorescence polarization was measured on the microchip and theophylline concentrations in serum were obtained. Regression analysis of the correlations was done between the results given by the microchip-based FPIA and the conventional cloned enzyme donor immunoassay (CEDIA), and between the results given by the microchip-based FPIA and the conventional particle-enhanced turbidimetric inhibition immunoassay (PETINIA). We successfully carried out a quantitative analysis of theophylline in serum at values near its therapeutic range in 65 s. The results obtained by the microchip-based FPIA correlated well with CEDIA and PETINIA results; the correlation coefficients (R(2)) were 0.986 and 0.989, respectively. The FPIA system is a simple and rapid method for point-of-care testing of drugs in serum, and its accuracy is the same as the conventional CEDIA and PETINIA. It is essential to use real samples from patients and to confirm good correlations with conventional methods for a study on the realization of microchip. © Springer-Verlag 2011

  14. 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.

  15. 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.

  16. Segmented trapped vortex cavity

    NASA Technical Reports Server (NTRS)

    Grammel, Jr., Leonard Paul (Inventor); Pennekamp, David Lance (Inventor); Winslow, Jr., Ralph Henry (Inventor)

    2010-01-01

    An annular trapped vortex cavity assembly segment comprising includes a cavity forward wall, a cavity aft wall, and a cavity radially outer wall there between defining a cavity segment therein. A cavity opening extends between the forward and aft walls at a radially inner end of the assembly segment. Radially spaced apart pluralities of air injection first and second holes extend through the forward and aft walls respectively. The segment may include first and second expansion joint features at distal first and second ends respectively of the segment. The segment may include a forward subcomponent including the cavity forward wall attached to an aft subcomponent including the cavity aft wall. The forward and aft subcomponents include forward and aft portions of the cavity radially outer wall respectively. A ring of the segments may be circumferentially disposed about an axis to form an annular segmented vortex cavity assembly.

  17. Trapped antihydrogen.

    PubMed

    Andresen, G B; Ashkezari, M D; Baquero-Ruiz, M; Bertsche, W; Bowe, P D; Butler, E; 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; Kurchaninov, L; Madsen, N; Menary, S; Nolan, P; Olchanski, K; Olin, A; Povilus, A; Pusa, P; Robicheaux, F; Sarid, E; el Nasr, S Seif; Silveira, D M; So, C; Storey, J W; Thompson, R I; van der Werf, D P; Wurtele, J S; Yamazaki, Y

    2010-12-02

    Antimatter was first predicted in 1931, by Dirac. Work with high-energy antiparticles is now commonplace, and anti-electrons are used regularly in the medical technique of positron emission tomography scanning. Antihydrogen, the bound state of an antiproton and a positron, has been produced at low energies at CERN (the European Organization for Nuclear Research) since 2002. Antihydrogen is of interest for use in a precision test of nature's fundamental symmetries. The charge conjugation/parity/time reversal (CPT) theorem, a crucial part of the foundation of the standard model of elementary particles and interactions, demands that hydrogen and antihydrogen have the same spectrum. Given the current experimental precision of measurements on the hydrogen atom (about two parts in 10(14) for the frequency of the 1s-to-2s transition), subjecting antihydrogen to rigorous spectroscopic examination would constitute a compelling, model-independent test of CPT. Antihydrogen could also be used to study the gravitational behaviour of antimatter. However, so far experiments have produced antihydrogen that is not confined, precluding detailed study of its structure. Here we demonstrate trapping of antihydrogen atoms. From the interaction of about 10(7) antiprotons and 7 × 10(8) positrons, we observed 38 annihilation events consistent with the controlled release of trapped antihydrogen from our magnetic trap; the measured background is 1.4 ± 1.4 events. This result opens the door to precision measurements on anti-atoms, which can soon be subjected to the same techniques as developed for hydrogen.

  18. 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.

  19. 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.

  20. 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)

  1. Ring King

    NASA Image and Video Library

    2014-08-18

    Saturn reigns supreme, encircled by its retinue of rings. Although all four giant planets have ring systems, Saturn's is by far the most massive and impressive. Scientists are trying to understand why by studying how the rings have formed and how they have evolved over time. Also seen in this image is Saturn's famous north polar vortex and hexagon. This view looks toward the sunlit side of the rings from about 37 degrees above the ringplane. The image was taken with the Cassini spacecraft wide-angle camera on May 4, 2014 using a spectral filter which preferentially admits wavelengths of near-infrared light centered at 752 nanometers. The view was acquired at a distance of approximately 2 million miles (3 million kilometers) from Saturn. Image scale is 110 miles (180 kilometers) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA18278

  2. Hybridization thermodynamics of DNA oligonucleotides during microchip capillary electrophoresis.

    PubMed

    Wynne, Thomas M; McCallum, Christopher; Del Bonis-O'Donnell, Jackson Travis; Crisalli, Pete; Pennathur, Sumita

    2015-03-03

    Capillary electrophoresis (CE) is a powerful analytical tool for performing separations and characterizing properties of charged species. For reacting species during a CE separation, local concentrations change leading to nonequilibrium conditions. Interpreting experimental data with such nonequilibrium reactive species is nontrivial due to the large number of variables involved in the system. In this work we develop a COMSOL multiphysics-based numerical model to simulate the electrokinetic mass transport of short interacting ssDNAs in microchip capillary electrophoresis. We probe the importance of the dissociation constant, K(D), and the concentration of DNA on the resulting observed mobility of the dsDNA peak, μ(w), by using a full sweep of parametric simulations. We find that the observed mobility is strongly dependent on the DNA concentration and K(D), as well as ssDNA concentration, and develop a relation with which to understand this dependence. Furthermore, we present experimental microchip capillary electrophoresis measurements of interacting 10 base ssDNA and its complement with changes in buffer ionic strength, DNA concentration, and DNA sequence to vary the system equilibria. We then compare our results to thermodynamically calculated K(D) values.

  3. 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.

  4. 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.

  5. 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).

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Pencil graphite leads as simple amperometric sensors for microchip electrophoresis.

    PubMed

    Natiele Tiago da Silva, Eiva; Marques Petroni, Jacqueline; Gabriel Lucca, Bruno; Souza Ferreira, Valdir

    2017-08-22

    In this work, we demonstrate for the first time the use of inexpensive commercial pencil graphite leads as simple amperometric sensors for microchip electrophoresis. A PDMS support containing one channel was fabricated through soft lithography and sanded pencil graphite leads were inserted into this channel to be used as working electrodes. The electrochemical and morphological characterization of the sensor was carried out. The graphite electrode was coupled to PDMS microchips in end-channel configuration and electrophoretic experiments were performed using nitrite and ascorbate as probe analytes. The analytes were successfully separated and detected in well-defined peaks with satisfactory resolution using the microfluidic platform proposed. The repeatability of the pencil graphite electrode was satisfactory (RSD values of 1.6% for nitrite and 12.3 % for ascorbate regarding the peak currents) and its lifetime was estimated to be ca. 700 electrophoretic runs over a cost of ca. $ 0.05 per electrode. The limits of detection achieved with the proposed system were 2.8 μM for nitrite and 5.7 μM for ascorbate. For proof of principle, the pencil graphite electrode was employed for the real analysis of well water samples and nitrite was successfully quantified at levels below its maximum contaminant level established in Brazil and US. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  12. 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.

  13. 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.

  14. 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.

  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. Fabrication and functional demonstration of a smart electrode with a built-in CMOS microchip for neural stimulation of a retinal prosthesis.

    PubMed

    Noda, Toshihiko; Fujisawa, Takumi; Kawasaki, Ryohei; Tashiro, Hiroyuki; Takehara, Hiroaki; Sasagawa, Kiyotaka; Tokuda, Takashi; Ohta, Jun

    2015-01-01

    In this study, we propose an advanced architecture of a smart electrode for neural stimulation of a retinal prosthesis. A feature of the proposed architecture is embedding CMOS microchips into the core of the stimulus electrodes. Microchip integration without dead space on the array is possible. Additionally, higher durability can be expected because the microchips are protected by the stimulus electrodes like a metal casing. Dedicated circular-shaped CMOS microchips were designed and fabricated. The microchip measured 400 μm in diameter. Stimulus electrodes that had a microcavity for embedding the microchip were also fabricated. In the assembly process, the CMOS microchip was mounted on a flexible substrate, and then the stimulus electrode was mounted to cover the microchip. The microchip was completely built into the inside of the electrode. By performing an ex-vivo experiment using the extracted eyeball of a pig, stimulus function of the electrode was demonstrated successfully.

  17. Vascular rings.

    PubMed

    Backer, Carl L; Mongé, Michael C; Popescu, Andrada R; Eltayeb, Osama M; Rastatter, Jeffrey C; Rigsby, Cynthia K

    2016-06-01

    The term vascular ring refers to congenital vascular anomalies of the aortic arch system that compress the esophagus and trachea, causing symptoms related to those two structures. The most common vascular rings are double aortic arch and right aortic arch with left ligamentum. Pulmonary artery sling is rare and these patients need to be carefully evaluated for frequently associated tracheal stenosis. Another cause of tracheal compression occurring only in infants is the innominate artery compression syndrome. In the current era, the diagnosis of a vascular ring is best established by CT imaging that can accurately delineate the anatomy of the vascular ring and associated tracheal pathology. For patients with a right aortic arch there recently has been an increased recognition of a structure called a Kommerell diverticulum which may require resection and transfer of the left subclavian artery to the left carotid artery. A very rare vascular ring is the circumflex aorta that is now treated with the aortic uncrossing operation. Patients with vascular rings should all have an echocardiogram because of the incidence of associated congenital heart disease. We also recommend bronchoscopy to assess for additional tracheal pathology and provide an assessment of the degree of tracheomalacia and bronchomalacia. The outcomes of surgical intervention are excellent and most patients have complete resolution of symptoms over a period of time. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. Immobilized MutS-Mediated Error Removal of Microchip-Synthesized DNA.

    PubMed

    Wan, Wen; Wang, Dongmei; Gao, Xiaolian; Hong, Jiong

    2017-01-01

    Applications of microchip-synthesized oligonucleotides for de novo gene synthesis are limited primarily by their high error rates. The mismatch binding protein MutS, which can specifically recognize and bind to mismatches, is one of the cheapest tools for error correction of synthetic DNA. Here, we describe a protocol for removing errors in microchip-synthesized oligonucleotides and for the assembly of DNA segments using these oligonucleotides. This protocol can also be used in traditional de novo gene DNA synthesis.

  6. 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.

  7. Hog-ringer speeds seed trap construction

    Treesearch

    D.O. Hall

    1964-01-01

    An upholsterer's hog-ringer, with Hill's No. 1 pig rings, increased production of one-foot-square wire seed traps by 25 percent. A design modification allowed two bottom sections to be cut from a 36-inch roll of wire.

  8. Conical Fresnel zone lens for optical trapping

    NASA Astrophysics Data System (ADS)

    Vijayakumar, A.; Parthasarathi, Praveen; Iyengar, Shruthi S.; Selvan, Rekha; Ananthamurthy, Sharath; Bhattacharya, Shanti; Bhattacharya, Sarbari

    2015-06-01

    The phase of a negative axicon is combined with that of a Fresnel zone lens (FZL) to obtain an element labelled as conical FZL, which can generate a focused ring pattern at the focal plane of the FZL. The phase integration is achieved by modifying the location and width of zones of FZL in accordance with the phase variation of the negative axicon. The element was designed for a high power laser with a wavelength of 1064 nm, focal length and diameter of conical FZL of 30 mm and 8 mm respectively and for a ring diameter of 50 μm. The element was fabricated using photolithography. The pattern was transferred from the resist layer to the borosilicate glass plates by dry etching to achieve an etch depth of 1064 nm. The etch depth measured using confocal microscope was 1034 nm at the central part and 930 nm for the outermost part of the device with a maximum error of 12.5% at the outermost part and 3% at the central part. The element was used in an optical trapping experiment. The ring pattern generated by the conical FZL was reimaged into the trapping plane using a tightly focusing microscopic objective. Polystyrene beads with diameters of 3 μm were suspended in deionized distilled water at the trapping plane. The element was found to trap multiple particles in to the same trap.

  9. 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 .

  10. Determination of calprotectin in gingival crevicular fluid by immunoassay on a microchip.

    PubMed

    Kido, Jun-ichi; Abe, Kaori; Yatsushiro, Shouki; Bando, Mika; Hiroshima, Yuka; Nagata, Toshihiko; Ooie, Toshihiko; Tanaka, Masato; Kataoka, Masatoshi

    2012-10-01

    Gingival crevicular fluid (GCF) contains calprotectin, which appears to be a useful biomarker for periodontal diseases because of its high level in GCF from periodontally diseased pockets. To determine calprotectin in GCF that has a very small volume, sandwich enzyme-linked immunosorbent assay (ELISA) on a microchip was performed and its utility was estimated. Anti-calprotectin primary antibody was discharged on a microchip using a piezoelectric inkjet printing system. Calprotectin standard and calprotectin in GCF samples from eleven subjects were determined by the ELISA method with the prepared microchip and their values were compared with those obtained by conventional ELISA. Using the ELISA on a microchip, a reasonable standard curve of calprotectin protein (1.56-100 ng/mL) was obtained. Calprotectin in GCF samples was quantified and showed reasonable values in accordance with the condition of periodontal diseases. The values determined by the microchip method and conventional ELISA showed a significant linear relationship (R(2)=0.981). Calprotectin in GCF was determined using the ELISA on a microchip with high efficiency and this ELISA method for calprotectin determination may become a useful method for diagnosing periodontal diseases. Copyright © 2012 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  11. Analysis of T-Cell Receptor-γ Gene Rearrangements Using Oligonucleotide Microchip

    PubMed Central

    Gra, Olga A.; Sidorova, Julia V.; Nikitin, Eugene A.; Turygin, Alexander Y.; Surzhikov, Sergey A.; Melikyan, Anait L.; Sudarikov, Andrey B.; Zasedatelev, Alexander S.; Nasedkina, Tatyana V.

    2007-01-01

    T-cell clonality estimation is important for the differential diagnosis between malignant and nonmalignant T-cell proliferation. Routinely used methods include polymerase chain reaction (PCR) analysis of T-cell receptor-γ (TCR-γ) gene rearrangements followed by Genescan analysis, polyacrylamide gel electrophoresis, or heteroduplex analysis to visualize amplification products. Here, we present a new method for the analysis after PCR of TCR-γ rearrangements using hybridization on oligonucleotide microchip. A microchip was designed to contain specific probes for all functional variable (V) and joining (J) gene segments involved in rearrangements of the TCR-γ locus. Fluorescently labeled fragments of rearranged γ-chain from patients and donors were obtained in a multiplex nested PCR and hybridized with a microchip. The results were detected using a portable microchip analyzer. Samples from 49 patients with T-cell lymphomas or leukemias and 47 donors were analyzed for T-cell clonality by microchip and single-strand conformation polymorphism analysis, which served as a standard reference method. Comparison of two techniques showed full concordance of the results. The microchip-based approach also allowed the identification of V and J gene segments involved in the particular TCR-γ rearrangement. The sensitivity of the method is sufficient to determine 10% of clonal cells in the sample. PMID:17384218

  12. On-chip immunoassay of a cardiac biomarker in serum using a polyester-toner microchip.

    PubMed

    Kim, Ah Rahn; Kim, Joo Yeon; Choi, Kihwan; Chung, Doo Soo

    2013-05-15

    An on-chip immunoassay to detect C-reactive protein (CRP) was performed using a polyester-toner (PT) microchip. CRP is a highly conserved plasma protein responding to inflammation and is used for clinical purposes to diagnose an inflammatory state. For rapid analysis and specific interactions in immunoassays, extensive studies using microfluidic chips have been carried out. Recently, a simple technique to fabricate a disposable PT microchip by a direct printing process was developed and several applications were introduced. One major drawback of the PT microchip, however, is the poor separation performance due to the quality of the microfluidic structures. This problem for a PT microchip can be overcome using a cleavable tag immunoassay, which requires minimal separation performance. After analytes are conjugated onto antibodies which are immobilized on the surface of microbeads placed on the PT microchip, a second group of fluorescently tagged antibodies are added and complexed with the analytes. The tag is then cleaved and the solution containing the cleaved tag is analyzed by electrophoresis. The time needed for the complete analysis to be carried out on a PT microchip was less than 35 min. The dynamic range of the CRP in 10-fold diluted serum was 0.3-100 mg/L and the limit of detection was 0.3 mg/L, which demonstrated the possibility of a quantitative analysis of CRP in serum in clinical trials. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Vacuum membrane distillation by microchip with temperature gradient.

    PubMed

    Zhang, Yaopeng; Kato, Shinji; Anazawa, Takanori

    2010-04-07

    A multilayered microchip (25 x 95 mm) used for vacuum distillation is designed, fabricated and tested by rectification of a water-methanol mixture. The polymer chip employs a cooling channel to generate a temperature gradient along a distillation channel below, which is separated into a channel (72 microm deep) for liquid phase and a channel (72 microm deep) for vapor phase by an incorporated microporous poly(tetrafluoroethylene) (PTFE) membrane. The temperature gradient is controlled by adjusting hotplate temperature and flow rate of cooling water to make the temperatures in the stripping section higher than the increasing boiling points of the water-enriched liquids and the temperatures in the rectifying section lower than the decreasing dew points of the methanol-enriched vapors. The effects of temperature gradient, feed composition, feed flow rate and membrane pore size on the micro distillation are also investigated. A theoretical plate number up to 1.8 is achieved at the optimum conditions.

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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. © 2013 Veterinary Radiology & Ultrasound.

  7. Photoassociative ionization of Na inside a storage ring

    NASA Astrophysics Data System (ADS)

    Paiva, R.; Muhammad, R.; Shiozaki, R.; de Oliveira, A. L.; Morizot, O.; Bagnato, V. S.; Magalhães, K. M. F.

    2012-04-01

    Motivated by recent interest in low dimensional arrays of atoms, we experimentally investigated the way cold collisional processes are affected by the geometry of the considered atomic sample. More specifically, we studied the case of photoassociative ionization (PAI) both in a storage ring where collision is more unidirectional in character and in a trap with clear undefinition of collision axis. First, creating a ring shaped trap (atomotron) we investigated two-color PAI dependence with intensity and polarization of a probing laser. The intensity dependence of the PAI rate was also measured in a magneto-optical trap presenting equivalent temperature and density conditions. Indeed, the results show that in the ring trap, the value of the PAI rate constant is much lower and does not show evidences of saturation, unlike in the case of the 3D-MOT. Cold atomic collisions in storage ring may represent new possibilities for study.

  8. 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.

  9. 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.

  10. A new microcolumn-type microchip for examining the expression of chimeric fusion genes using a nucleic acid sandwich hybridization technique.

    PubMed

    Ohnishi, Michihiro; Sasaki, Naoyuki; Kishimoto, Takuya; Watanabe, Hidetoshi; Takagi, Masatoshi; Mizutani, Shuki; Kishii, Noriyuki; Yasuda, Akio

    2014-11-01

    We report a new type of microcolumn installed in a microchip. The architecture allows use of a nucleic acid sandwich hybridization technique to detect a messenger RNA (mRNA) chain as a target. Data are presented that demonstrate that the expression of a chimeric fusion gene can be detected. The microcolumn was filled with semi-transparent microbeads made of agarose gel that acted as carriers, allowing increased efficiency of the optical detection of fluorescence from the microcolumn. The hybrid between the target trapped on the microbeads and a probe DNA labeled with a fluorescent dye was detected by measuring the intensity of the fluorescence from the microcolumn directly. These results demonstrate an easy and simple method for determining the expression of chimeric fusion genes with no preamplification. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. 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

  12. 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.

  13. Capillary liquid chromatography-microchip atmospheric pressure chemical ionization-mass spectrometry.

    PubMed

    Ostman, Pekka; Jäntti, Sirkku; Grigoras, Kestas; Saarela, Ville; Ketola, Raimo A; Franssila, Sami; Kotiaho, Tapio; Kostiainen, Risto

    2006-07-01

    A miniaturized nebulizer chip for capillary liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry (capillary LC-microchip APCI-MS) is presented. The APCI chip consists of two wafers, a silicon wafer and a Pyrex glass wafer. The silicon wafer has a DRIE etched through-wafer nebulizer gas inlet, an edge capillary insertion channel, a stopper, a vaporizer channel and a nozzle. The platinum heater electrode and pads for electrical connection were patterned on to the Pyrex glass wafer. The two wafers were joined by anodic bonding, creating a microchip version of an APCI-source. The sample inlet capillary from an LC column is directly connected to the vaporizer channel of the APCI chip. The etched nozzle in the microchip forms a narrow sample plume, which is ionized by an external corona needle, and the formed ions are analyzed by a mass spectrometer. The nebulizer chip enables for the first time the use of low flow rate separation techniques with APCI-MS. The performance of capillary LC-microchip APCI-MS was tested with selected neurosteroids. The capillary LC-microchip APCI-MS provides quantitative repeatability and good linearity. The limits of detection (LOD) with a signal-to-noise ratio (S/N) of 3 in MS/MS mode for the selected neurosteroids were 20-1000 fmol (10-500 nmol l(-1)). LODs (S/N = 3) with commercial macro APCI with the same compounds using the same MS were about 10 times higher. Fast heat transfer allows the use of the optimized temperature for each compound during an LC run. The microchip APCI-source provides a convenient and easy method to combine capillary LC to any API-MS equipped with an APCI source. The advantages and potentials of the microchip APCI also make it a very attractive interface in microfluidic APCI-MS.

  14. 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.

  15. 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.

  16. Developments on the Toroid Ion Trap Analyzer

    SciTech Connect

    Lammert, S.A.; Thompson, C.V.; Wise, M.B.

    1999-06-13

    Investigations into several areas of research have been undertaken to address the performance limitations of the toroid analyzer. The Simion 3D6 (2) ion optics simulation program was used to determine whether the potential well minimum of the toroid trapping field is in the physical center of the trap electrode structure. The results (Figures 1) indicate that the minimum of the potential well is shifted towards the inner ring electrode by an amount approximately equal to 10% of the r0 dimension. A simulation of the standard 3D ion trap under similar conditions was performed as a control. In this case, the ions settle to the minimum of the potential well at a point that is coincident with the physical center (both radial and axial) of the trapping electrodes. It is proposed that by using simulation programs, a set of new analyzer electrodes can be fashioned that will correct for the non- linear fields introduced by curving the substantially quadrupolar field about the toroid axis in order to provide a trapping field similar to the 3D ion trap cross- section. A new toroid electrode geometry has been devised to allow the use of channel- tron style detectors in place of the more expensive multichannel plate detector. Two different versions have been designed and constructed - one using the current ion trap cross- section (Figure 2) and another using the linear quedrupole cross- section design first reported by Bier and Syka (3).

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Microchip-based Immunomagnetic Detection of Circulating Tumor Cell

    PubMed Central

    Huang, Yu-Yen; Lane, Nancy; Huebschman, Michael; Uhr, Jonathan W.; Frenkel, Eugene P.; Zhang, Xiaojing

    2012-01-01

    Screening for circulating tumor cells (CTCs) in blood has been an object of interest for evidence of progressive disease, status of disease activity, recognition of clonal evolution of molecular changes and for possible early diagnosis of cancer. We describe a new method of microchip-based immunomagnetic CTC detection, in which the benefits of both immunomagnetic assay and the microfluidic device are combined. As the blood sample flows through the microchannel closely above arrayed magnets, cancer cells labeled with magnetic nanoparticles are separated from blood flow and deposited at the bottom wall of the glass coverslip, which allows direct observation of captured cells with a fluorescence microscope. A polydimethylsiloxane (PDMS)-based microchannel fixed on a glass coverslip was used to screen blood samples. The thin, flat dimensions of the microchannel, combined with the sharp magnetic field gradient in the vicinity of arrayed magnets with alternate polarities, lead to an effective capture of labeled cells. Comparing to the commercially available CellSearch™ system, less (25%) magnetic particles are required to achieve a comparable capture rate, while the screening speed (at optimal blood flow rate of 10 mL/hour) is more than five times faster than those reported previously with a microchannel-based assay. For the screening experiment, blood drawn from healthy subjects into CellSave™ tubes was spiked with cultured cancer cell lines of COLO205 and SKBR3. The blood was then kept at room temperature for 48 hours before the screening, emulating the actual clinical cases of blood screening. Customized Fe3O4 magnetic nanoparticles (Veridex Ferrofluid™) conjugated to anti-Epithelial cell adhesion molecule (EpCAM) antibodies were introduced into the blood samples to label cancer cells, and the blood was then run through the microchip device to capture the labelled cells. After capture, the cells were stained with fluorescently labelled anti-cytokeratin, DAPI and

  2. Microchip-based immunomagnetic detection of circulating tumor cells.

    PubMed

    Hoshino, Kazunori; Huang, Yu-Yen; Lane, Nancy; Huebschman, Michael; Uhr, Jonathan W; Frenkel, Eugene P; Zhang, Xiaojing

    2011-10-21

    Screening for circulating tumor cells (CTCs) in blood has been an object of interest for evidence of progressive disease, status of disease activity, recognition of clonal evolution of molecular changes and for possible early diagnosis of cancer. We describe a new method of microchip-based immunomagnetic CTC detection, in which the benefits of both immunomagnetic assay and the microfluidic device are combined. As the blood sample flows through the microchannel closely above arrayed magnets, cancer cells labeled with magnetic nanoparticles are separated from blood flow and deposited at the bottom wall of the glass coverslip, which allows direct observation of captured cells with a fluorescence microscope. A polydimethylsiloxane (PDMS)-based microchannel fixed on a glass coverslip was used to screen blood samples. The thin, flat dimensions of the microchannel, combined with the sharp magnetic field gradient in the vicinity of arrayed magnets with alternate polarities, lead to an effective capture of labeled cells. Compared to the commercially available CellSearch™ system, fewer (25%) magnetic particles are required to achieve a comparable capture rate, while the screening speed (at an optimal blood flow rate of 10 mL h(-1)) is more than five times faster than those reported previously with a microchannel-based assay. For the screening experiment, blood drawn from healthy subjects into CellSave™ tubes was spiked with cultured cancer cell lines of COLO205 and SKBR3. The blood was then kept at room temperature for 48 hours before the screening, emulating the actual clinical cases of blood screening. Customized Fe(3)O(4) magnetic nanoparticles (Veridex Ferrofluid™) conjugated to anti-epithelial cell adhesion molecule (EpCAM) antibodies were introduced into the blood samples to label cancer cells, and the blood was then run through the microchip device to capture the labelled cells. After capture, the cells were stained with fluorescent labelled anti

  3. A high-speed, high-performance on-chip integrated reverse transcription (RT)-microchip.

    PubMed

    Lee, Hwanyong; Han, Nari; Choi, In-Hak; Han, Ki-Ho

    2013-02-01

    This report introduces an on-chip integrated reverse transcription (RT)-microchip, which includes two genetic functionalities of RNA extraction and cDNA synthesis. In the RNA extraction compartment, RNA is extracted from peripheral blood lysate within 1 min, by lateral magnetophoresis using magnetic oligo-dT beads. The extracted RNA is then collected and used directly to produce cDNA in the cDNA synthesis microchamber, which is monolithically integrated with the RNA extraction compartment. To verify the superiority of the proposed RT-microchip, RT-PCR amplification was performed using cDNA harvested from the RT-microchip, and the results were compared with those obtained using typical RNA extraction methods such as a silica matrix column and magnetic oligo-dT beads. The RT-PCR amplification results using 100 μl of blood showed that the intensity of the bands in gel electrophoresis of the RT-microchip was 2-fold stronger than that of the silica matrix column and 2.65-fold stronger than that of the magnetic oligo-dT beads. The results demonstrate that the RT-microchip technique is the most sensitive of the tested methods.

  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. Dyneon THV, a fluorinated thermoplastic as a novel material for microchip capillary electrophoresis.

    PubMed

    Aboud, Nacéra; Ferraro, Davide; Taverna, Myriam; Descroix, Stéphanie; Smadja, Claire; Thuy Tran, N

    2016-10-21

    In this work, we have investigated Dyneon THV, a fluorinated material, as a new material to afford electrokinetic separations in microfluidic devices. To overcome protein adsorption, two poly(ethylene oxide) (PEO)-based coatings have been investigated: Pluronic F127 and PEO stearate 40. The best results were obtained with the PEO stearate 40 coating which allowed decreasing the surface contact angle from 91 ± 3 to 76°± 3. With this surface treatment, a 66% reduction of the electroosmotic mobility at pH 8.0 and a marked suppression of protein adsorption were observed compared to a native Dyneon THV microchip. Finally, a separation of fluorescently labeled proteins (bovine serum albumin and trypsin inhibitor), well-known for their strong tendency to adsorb on hydrophobic surfaces, was successfully achieved in an HEPES buffer with a PEO stearate 40 treated microchip by capillary zone electrophoresis. Furthermore, we demonstrated the possibility to perform non-aqueous capillary electrophoresis analysis of hydrophobic dyes using various solvents in untreated microchips. The overall results demonstrated not only the suitability of the Dyneon THV microchip for electrokinetic separations, but also its versatility allowing different separation modes to be implemented with the same microchip material.

  6. Gas chromatography-microchip atmospheric pressure chemical ionization-mass spectrometry.

    PubMed

    Ostman, Pekka; Luosujärvi, Laura; Haapala, Markus; Grigoras, Kestas; Ketola, Raimo A; Kotiaho, Tapio; Franssila, Sami; Kostiainen, Risto

    2006-05-01

    An atmospheric pressure chemical ionization (APCI) microchip is presented for combining a gas chromatograph (GC) to a mass spectrometer (MS). The chip includes capillary insertion channel, stopper, vaporizer channel, nozzle and nebulizer gas inlet fabricated on the silicon wafer, and a platinum heater sputtered on a glass wafer. These two wafers are joined by anodic bonding creating a two-dimensional version of an APCI microchip. The sample from GC is directed via heated transfer line capillary to the vaporizer channel of the APCI chip. The etched nozzle forms narrow sample plume, which is ionized by an external corona discharge needle, and the ions are analyzed by a mass spectrometer. The GC-microchip APCI-MS combination provides an efficient method for qualitative and quantitative analysis. The spectra produced by microchip APCI show intensive protonated molecule and some fragmentation products as in classical chemical ionization for structure elucidation. In quantitative analysis the GC-microchip APCI-MS showed good linearity (r(2) = 0.9989) and repeatability (relative standard deviation 4.4%). The limits of detection with signal-to-noise ratio of three were between 0.5 and 2 micromol/L with MS mode using selected ion monitoring and 0.05 micromol/L with MS/MS using multiple reaction monitoring.

  7. 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.

  8. 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.

  9. 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}.

  10. 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.

  11. 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.

  12. 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.

  13. Recent applications of microchip electrophoresis to biomedical analysis.

    PubMed

    Nuchtavorn, Nantana; Suntornsuk, Worapot; Lunte, Susan M; Suntornsuk, Leena

    2015-09-10

    Many separation methods have been developed for biomedical analysis, including chromatographic (e.g. high performance liquid chromatography (HPLC) and gas chromatography (GC)) and electrophoretic methods (e.g. gel electrophoresis and capillary electrophoresis (CE)). Among these techniques, CE provides advantages in terms of high separation efficiency, simplicity, low sample and solvent volume consumption, short analysis time and applicability to a wide range of biomedically important substances. Microchip electrophoresis (ME) is a miniaturized platform of CE and is now considered as a simpler and more convenient alternative, which has demonstrated potential in analytical chemistry. High-throughput, cost-effective and portable analysis systems can be developed using ME. The current review describes different separation modes and detectors that have been employed in ME to analyze various classes of biomedical analytes (e.g. pharmaceuticals and related substances, nucleic acids, amino acids, peptides, proteins, antibodies and antigens, carbohydrates, cells, cell components and lysates). Recent applications (during 2010-2014) in these areas are presented in tables and some significant findings are highlighted. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. 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

  15. Competitive immunoassay of progesterone by microchip electrophoresis with chemiluminescence detection.

    PubMed

    Ye, Fanggui; Liu, Jinwen; Huang, Yong; Li, Shutin; Zhao, Shulin

    2013-10-01

    A sensitive and rapid homogeneous immunoassay method based on microchip electrophoresis-chemiluminescence detection (MCE-CL) using luminol-hydrogen peroxide as chemiluminescence system catalyzed by horseradish peroxidase (HRP) was developed for the determination of progesterone (P). The assay was based on the competitive immunoreactions between HRP-labeled P antigen (HRP-P) and P with a limited amount of anti-P mouse monoclonal antibody (Ab), and MCE separation of free HRP-P and HRP-P-Ab immunocomplex followed by CL detection. The effect of various factors such as conditions for the CL reaction, MCE and incubation time for the immunoreactions were examined and optimized. Under optimal assay conditions, the MCE separation was accomplished within 80s. The linear range of detection for P was 8-800nM with a detection limit of 3.8nM (signal/noise ratio=3). This present method has been applied to determine P in human serum samples from normal and pregnant women. The result indicates that the proposed MCE-CL based homogeneous immunoassay method can serve as an alternative tool for clinical assay of P. Copyright © 2013. Published by Elsevier B.V.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. Multiplexed detection of biological agents using optical microchip sensors

    NASA Astrophysics Data System (ADS)

    Bhatta, D.; McDonnell, M. B.; Perkins, E.

    2010-10-01

    A multi-channel optical microchip sensor system suitable for real-time, label-free detection of a wide range of biological agents is presented. SpectroSensTM chips containing multiple high-precision planar Bragg gratings are exploited as lowcost, robust refractive index sensors. Sensitivity to biological agents is conferred by functionalising individual sensing regions with different antibodies selected against numerous targets of interest. Antigen binding to the surfaceimmobilised antibodies results in localised changes in refractive index; upon laser-induced interrogation of the sensing region via optical fibres, these antibody-antigen interactions manifest as increases in wavelength of light reflected from the sensor chip. Real-time detection of multiple biological agents including bacterial cells/spores, viruses and toxins has been demonstrated. Further improvements to sensor performance including physical and chemical methods are also investigated. This multi-analyte capability highlights the potential use of this sensing technology in applications ranging from bio-hazard detection for defence purposes to point-of-care clinical diagnostics.

  4. 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.

  5. Rectangular pulsed LD pumped saturable output coupler (SOC) Q-switched microchip laser

    NASA Astrophysics Data System (ADS)

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

    2017-02-01

    We studied the cw LD and rectangular pulsed LD pumped saturable output coupler (SOC) passively Q-switched Nd:YVO4 transmission microchip laser experimentally. We demonstrated that the SOC passively Q-switched Nd:YVO4 transmission microchip laser pumped by a highly stabilized narrow bandwidth pulsed LD has a much lower timing jitter than pumped by a continuous wave (CW) LD, especially at low output frequency regime. By changing the pump beam size in the rectangular shape pulsed pump scheme, the output frequency can be achieved from 333.3 kHz to 71.4 kHz, while the relative timing jitter decreased from 0.09865% to 0.03115% accordingly. Additionally, the microchip laser has a good stability of output power, the power fluctuation below 2%.

  6. 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

  7. 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.

  8. 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.

  9. 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.

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

    PubMed

    Saylor, Rachel A; Lunte, Susan M

    2015-02-20

    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 with selective detection yields a "separation-based sensor" capable of monitoring multiple analytes in near real time. For monitoring biological events, analysis of microdialysis samples often 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. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. 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.

  12. Nonlinear photochemistry and 3D microfabrication with Q-switched Nd:YAG microchip lasers

    NASA Astrophysics Data System (ADS)

    Baldeck, Patrice L.; Scheul, Teodora; Bouriau, Michel; Stephan, Olivier; Malval, Jean-Pierre; Lin, Chih-Lang; Lin, Chin-Te; Tseng, Chang-Li; Huang, Cheng; Chung, Tien-Tung

    2011-10-01

    We review our recent advances in two-photon induced photochemistry to fabricate three-dimensional micro-objects made in polymers, proteins and noble metals using Q-switched Nd:YAG microchip lasers. We have synthesized a new photoinitiator that is about 4 times more sensitive for two-photon polymerisation with sub-nanosecond pulses at 532 nm. We describe the improvement of our fabrication process and strategies to obtain solid microstructures that correspond to their models. We report on our progress to make silver microstructures by the photoreduction of silver nitrate with microchip lasers at 1064nm.

  13. 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.

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

    SciTech Connect

    Stomakhin, A. A.; Vasiliskov, V. A.; Timofeev, E.; Schulga, D.; Cotter, R. J.; Mirzabekov, A. D.; Biochip Technology Center; Engelhardt Inst. of Molecular Biology; Moscow Inst. of Physics and Technology; Middle Atlantic Mass Spectrometry Lab.; Johns Hopkins Univ. School of Medicine

    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{sup o}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.

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. Trap centers in molybdates

    NASA Astrophysics Data System (ADS)

    Spassky, D. A.; Nagirnyi, V.; Mikhailin, V. V.; Savon, A. E.; Belsky, A. N.; Laguta, V. V.; Buryi, M.; Galashov, E. N.; Shlegel, V. N.; Voronina, I. S.; Zadneprovski, B. I.

    2013-10-01

    Charge carrier trapping centers have been studied in molybdates CaMoO4, SrMoO4 and PbMoO4 with the scheelite crystal structure as well as in ZnMoO4, which crystallize in a-ZnMoO4 structural type. The trap parameters such as activation energies and frequency factors have been determined. It is shown for the first time that both electrons and holes are trapped by the elements of regular crystal structure in ZnMoO4. The effect of the charge carrier trapping on luminescence properties is demonstrated. Potential influence of the traps on the scintillation process is discussed.

  4. 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.

  5. The Ring Sculptor

    NASA Image and Video Library

    2006-09-08

    Prometheus zooms across the Cassini spacecraft field of view, attended by faint streamers and deep gores in the F ring. This movie sequence of five images shows the F ring shepherd moon shaping the ring inner edge

  6. Beyond Bright Rings

    NASA Image and Video Library

    2009-12-30

    The tiny moon Pandora appears beyond the bright disk of Saturn rings in this image taken by NASA Cassini spacecraft. Pandora orbits outside the F ring and, in this image, is farther from Cassini than the rings are.

  7. [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.

  8. Highly-efficient multi-watt Yb:CaLnAlO4 microchip lasers

    NASA Astrophysics Data System (ADS)

    Loiko, Pavel; Serres, Josep Maria; Mateos, Xavier; Xu, Xiaodong; Xu, Jun; Yumashev, Konstantin; Griebner, Uwe; Petrov, Valentin; Aguiló, Magdalena; Díaz, Francesc; Major, Arkady

    2017-02-01

    Tetragonal rare-earth calcium aluminates, CaLnAlO4 where Ln = Gd or Y (CALGO and CALYO, respectively), are attractive laser crystal hosts due to their locally disordered structure and high thermal conductivity. In the present work, we report on highly-efficient power-scalable microchip lasers based on 8 at.% Yb:CALGO and 3 at.% Yb:CALYO crystals grown by the Czochralski method. Pumped by an InGaAs laser diode at 978 nm, the 6 mm-long Yb:CALGO microchip laser generated 7.79 W at 1057-1065 nm with a slope efficiency of η = 84% (with respect to the absorbed pump power) and an optical-to-optical efficiency of ηopt = 49%. The 3 mm-long Yb:CALYO microchip laser generated 5.06 W at 1048-1056 nm corresponding to η = 91% and ηopt = 32%. Both lasers produced linearly polarized output (σ- polarization) with an almost circular beam profile and beam quality factors M2 x,y <1.1. The output performance of the developed lasers was modeled yielding a loss coefficient as low as 0.004-0.007 cm-1. The results indicate that the Yb3+- doped calcium aluminates are very promising candidates for high-peak-power passively Q-switched microchip lasers.

  9. 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.

  10. Massive parallel analysis of DNA - Hoechst 33258 binding specificity with a generic oligonucleotide microchip.

    SciTech Connect

    Drobyshev, A. L.; Zasedatelev, A. S.; Yershov, G. M.; Mirzabekov, A. D.; Biochip Technology Center

    1999-10-15

    A generic oligodeoxyribonucleotide microchip was used to determine the sequence specificity of Hoechst 33258 binding to double-stranded DNA. The generic microchip contained 4096 oxctadeoxynucleo-tides in which all possible 4(6)= 4096 hexadeoxy-nucleotide sequences are flanked on both the 3'- and 5'-ends with equimolar mixtures of four bases. The microchip was manufactured by chemical immobilization of presynthesized 8mers within polyacrylamide gel pads. A selected set of immobilized 8mers was converted to double-stranded form by hybridization with a mixture of fluorescently labeled complementary 8mers. Massive parallel measurements of melting curves were carried out for the majority of 2080 6mer duplexes, in both the absence and presence of the Hoechst dye. The sequence-specific affinity for Hoechst 33258 was calculated as the increase in melting temperature caused by ligand binding. The dye exhibited specificity for A:T but not G:C base pairs. The affinity is low for two A:T base pairs, increases significantly for three, and reaches a plateau for four A:T base pairs. The relative ligand affinity for all trinucleotide and tetranucleotide sequences (A/T)(3)and (A/T)(4)was estimated. The free energy of dye binding to several duplexes was calculated from the equilibrium melting curves of the duplexes formed on the oligonucleotide microchips. This method can be used as a general approach for massive screening of the sequence specificity of DNA-binding compounds.

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. Observation of repetitively nanosecond pulse-width transverse patterns in microchip self-Q-switched laser

    SciTech Connect

    Dong, Jun; Ueda, Ken-ichi

    2006-05-15

    Repetitively nanosecond pulse-width transverse pattern formation in a plane-parallel microchip Cr,Nd: yttrium-aluminum-garnet (YAG) self-Q-switched laser was investigated. The complex point-symmetric transverse patterns were observed by varying the pump beam diameter incident on the Cr,Nd:YAG crystal. The gain guiding effect and the thermal effect induced by the pump power in microchip Cr,Nd:YAG laser control the oscillating transverse modes. These transverse pattern formations were due to the variation of the saturated inversion population and the thermal induced index profile along radial and longitudinal direction in the Cr,Nd:YAG crystal induced by the pump power incident on the Cr,Nd:YAG crystal. These were intrinsic properties of such a microchip self-Q-switched laser. The longitudinal distribution of the saturated inversion population inside the gain medium plays an important role on the transverse pattern formation. Different sets of the transverse patterns corresponds to the different saturated inversion population distribution inside microchip Cr,Nd:YAG crystal.

  16. 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).

  17. Enhanced Detection of Proteins in Microchip Separations by On-Chip Preconcentration

    SciTech Connect

    Foote, R.S.

    2001-05-24

    Microfluidic chips incorporating a semiporous glass filter were used to electrokinetically concentrate proteins on-chip prior to injection and electrophoretic analysis. Signal enhancements of >100-fold could be achieved for the microchip analysis of both native and SDS-denatured proteins using this technique.

  18. Microchips, microarrays, biochips and nanochips: personal laboratories for the 21st century.

    PubMed

    Kricka, L J

    2001-05-01

    Micro miniaturization of analytical procedures is having significant impact on diagnostic testing, and will enable highly complex clinical testing to be miniaturized and permit testing to move from the central laboratory into non-laboratory settings. The diverse range of micro analytical devices includes microchips, gene chips, bioelectronic chips. They have been applied to several clinically important assays (e.g., PCR, immunoassay). The main advantages of the new devices are integration of multiple steps in complex analytical procedures, diversity of application, sub-microliter consumption of reagents and sample, and portability. These devices form the basis of new and smaller analyzers (e.g., capillary electrophoresis) and may ultimately be used in even smaller devices useful in decentralized testing (lab-on-a-chip, personal laboratories). The impact of microchips on healthcare costs could be significant via timely intervention and monitoring, combined with improved treatments (e.g., microchip-based pharmacogenomic tests). Empowerment of health consumers to perform self-testing is limited, but microchips could accelerate this process and so produce a level of self-awareness of biochemical and genetic information hitherto unimaginable. The next level of miniaturization is the nanochip (nanometer-sized features) and the technological foundation for these futuristic devices is discernable in nanotubes and self-assembling molecular structures.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. 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.

  5. 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.

  6. 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

  7. Evaluation of pain and inflammation associated with hot iron branding and microchip transponder injection in horses.

    PubMed

    Lindegaard, Casper; Vaabengaard, Dorte; Christophersen, Mogens T; Ekstøm, Claus T; Fjeldborg, Julie

    2009-07-01

    To compare effects of hot iron branding and microchip transponder injection regarding aversive behavioral reactions indicative of pain and inflammation in horses. 7 adult horses. In a randomized controlled clinical crossover study, behavioral reactions to hot iron branding and microchip transponder injection were scored by 4 observers. Local and systemic inflammation including allodynia were assessed and compared by use of physiologic and biochemical responses obtained repeatedly for the 168-hour study period. Serum cortisol concentration was measured repeatedly throughout the first 24 hours of the study. Sham treatments were performed 1 day before and 7 days after treatments. Hot iron branding elicited a significantly stronger aversive reaction indicative of pain than did microchip transponder injection (odds ratio [OR], 12.83). Allodynia quantified by means of skin sensitivity to von Frey monofilaments was significantly greater after hot iron branding than after microchip transponder injection (OR, 2.59). Neither treatment induced signs of spontaneously occurring pain that were observed during the remaining study period, and neither treatment induced increased serum cortisol concentrations. Comparison with sham treatments indicated no memory of an unpleasant event. The hot iron branding areas had significantly increased skin temperature and swelling (OR, 14.6). Systemic inflammation as measured via serum amyloid A concentration was not detected after any of the treatments. Microchip transponder injection induced less signs of pain and inflammation and did not seem to pose a higher long-term risk than hot iron branding. Consequently, results indicated that hot iron branding does inflict more pain and should be abandoned where possible.

  8. 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

  9. Toward point-of-care testing for JAK2 V617F mutation on a microchip.

    PubMed

    Wang, Hua; Liu, Weiwei; Zhang, Xinju; Xu, Xiao; Kang, Zhihua; Li, Shibao; Wu, Zhiyuan; Yang, Zhiliu; Yao, Bo; Guan, Ming

    2015-09-04

    Molecular genetics now plays a crucial role in diagnosis, the identification of prognostic markers, and monitoring of hematological malignancies. Demonstration of acquired changes such as the JAK2 V617F mutation within myeloproliferative neoplasms (MPN) has quickly moved from a research setting to the diagnostic laboratory. Microfluidics-based assays can reduce the assay time and sample/reagent consumption and enhance the reaction efficiency; however, no current assay has integrated isothermal amplification for point-of-care MPN JAK2 V617F mutation testing with a microchip. In this report, an integrated microchip that performs the whole human blood genomic DNA extraction, loop-mediated isothermal nucleic acid amplification (LAMP) and visual detection for point-of-care genetic mutation testing is demonstrated. This method was validated on DNA from cell lines as well as on whole blood from patients with MPN. The results were compared with those obtained by unlabeled probe melting curve analysis. This chip enjoys a high accuracy, operability, and cost/time efficiency within 1h. All these benefits provide the chip with a potency toward a point-of-care genetic analysis. All samples identified as positive by unlabeled probe melting curve analysis (n=27) proved positive when tested by microchip assay. None of the 30 negative controls gave false positive results. In addition, a patient with polycythemia vera diagnosed as being JAK2 V617F-negative by unlabeled probe melting curve analysis was found to be positive by the microchip. This microchip would possibly be very attractive in developing a point-of-care platform for quick preliminary diagnosis of MPN or other severe illness in resource-limited settings. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Quantitative aspects of microchip isotachophoresis for high precision determination of main components in pharmaceuticals.

    PubMed

    Hradski, Jasna; Chorváthová, Mária Drusková; Bodor, Róbert; Sabo, Martin; Matejčík, Štefan; Masár, Marián

    2016-12-01

    Although microchip electrophoresis (MCE) is intended to provide reliable quantitative data, so far there is only limited attention paid to these important aspects. This study gives a general overview of key aspects to be followed to reach high-precise determination using isotachophoresis (ITP) on the microchip with conductivity detection. From the application point of view, the procedure for the determination of acetate, a main component in the pharmaceutical preparation buserelin acetate, was developed. Our results document that run-to-run fluctuations in the sample injection volume limit the reproducibility of quantitation based on the external calibration. The use of a suitable internal standard (succinate in this study) improved the repeatability of the precision of acetate determination from six to eight times. The robustness of the procedure was studied in terms of impact of fluctuations in various experimental parameters (driving current, concentration of the leading ions, pH of the leading electrolyte and buffer impurities) on the precision of the ITP determination. The use of computer simulation programs provided means to assess the ITP experiments using well-defined theoretical models. A long-term validity of the calibration curves on two microchips and two MCE equipments was verified. This favors ITP over other microchip electrophoresis techniques, when chip-to-chip or equipment-to-equipment transfer of the analytical method is required. The recovery values in the range of 98-101 % indicate very accurate determination of acetate in buserelin acetate, which is used in the treatment of hormone-dependent tumors. This study showed that microchip ITP is suitable for reliable determination of main components in pharmaceutical preparations.

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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).

  20. 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.

  1. Triblock copolymer-based microchip device for rapid analysis of stuffer-free multiplex ligation-dependent probe amplification products.

    PubMed

    Shin, Gi Won; Kim, Yong Tae; Heo, Hyun Young; Chung, Boram; Seo, Tae Seok; Jung, Gyoo Yeol

    2012-12-01

    Recent improvements in the multiplex ligation-dependent probe amplification (MLPA) method promise successful multiplex analysis of various genetic markers. In particular, it has been demonstrated that elimination of the stuffer sequence included in MLPA probes for length-dependent analysis substantially simplifies the probe design process and improves the accuracy of the analysis. As is the case for other CE-based methods, MLPA could be further developed on a microchip platform. However, high-resolution analysis of short MLPA probes requires careful microchip operation. In this study, we developed a microchip device for the multiplex analysis of five food-borne pathogens using a stuffer-free probe set. Microchip channel design and electrophoresis operating conditions were first optimized for reproducible analysis, after which two sieving matrices were tested. Finally, the method was validated using DNA samples isolated from intentionally infected milk. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. 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.

  3. 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).

  4. 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.

  5. 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.

  6. Towards trapped antihydrogen

    NASA Astrophysics Data System (ADS)

    Jørgensen, L. V.; Andresen, G.; Bertsche, W.; Boston, A.; Bowe, P. D.; Cesar, C. L.; Chapman, S.; Charlton, M.; Fajans, J.; Fujiwara, M. C.; Funakoshi, R.; Gill, D. R.; Hangst, J. S.; Hayano, R. S.; Hydomako, R.; Jenkins, M. J.; Kurchaninov, L.; Madsen, N.; Nolan, P.; Olchanski, K.; Olin, A.; Page, R. D.; Povilus, A.; Robicheaux, F.; Sarid, E.; Silveira, D. M.; Storey, J. W.; Thompson, R. I.; van der Werf, D. P.; Wurtele, J. S.; Yamazaki, Y.; Alpha Collaboration

    2008-02-01

    Substantial progress has been made in the last few years in the nascent field of antihydrogen physics. The next big step forward is expected to be the trapping of the formed antihydrogen atoms using a magnetic multipole trap. ALPHA is a new international project that started to take data in 2006 at CERN's Antiproton Decelerator facility. The primary goal of ALPHA is stable trapping of cold antihydrogen atoms to facilitate measurements of its properties. We discuss the status of the ALPHA project and the prospects for antihydrogen trapping.

  7. 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.

  8. 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.

  9. Uranus Tenth Ring

    NASA Image and Video Library

    1996-01-29

    On Jan. 23, 1986, NASA Voyager 2 discovered a tenth ring orbiting Uranus. The tenth ring is about midway between the bright, outermost epsilon ring and the next ring down, called delta. http://photojournal.jpl.nasa.gov/catalog/PIA00035

  10. 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.

  11. 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 ...

  12. 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.

  13. 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.

  14. 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. © 2014 Wiley Periodicals, Inc.

  15. 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.

  16. Search for trapped antihydrogen

    NASA Astrophysics Data System (ADS)

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

    2011-01-01

    We present the results of an experiment to search for trapped antihydrogen atoms with the ALPHA antihydrogen trap at the CERN Antiproton Decelerator. Sensitive diagnostics of the temperatures, sizes, and densities of the trapped antiproton and positron plasmas have been developed, which in turn permitted development of techniques to precisely and reproducibly control the initial experimental parameters. The use of a position-sensitive annihilation vertex detector, together with the capability of controllably quenching the superconducting magnetic minimum trap, enabled us to carry out a high-sensitivity and low-background search for trapped synthesised antihydrogen atoms. We aim to identify the annihilations of antihydrogen atoms held for at least 130 ms in the trap before being released over ∼30 ms. After a three-week experimental run in 2009 involving mixing of 10 7 antiprotons with 1.3×10 positrons to produce 6×10 antihydrogen atoms, we have identified six antiproton annihilation events that are consistent with the release of trapped antihydrogen. The cosmic ray background, estimated to contribute 0.14 counts, is incompatible with this observation at a significance of 5.6 sigma. Extensive simulations predict that an alternative source of annihilations, the escape of mirror-trapped antiprotons, is highly unlikely, though this possibility has not yet been ruled out experimentally.

  17. Liquid metal cold trap

    DOEpatents

    Hundal, Rolv

    1976-01-01

    A cold trap assembly for removing impurities from a liquid metal being provided with a hole between the incoming impure liquid metal and purified outgoing liquid metal which acts as a continuous bleed means and thus prevents the accumulation of cover gases within the cold trap assembly.

  18. 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

  19. 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.

  20. 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.}

  1. Synthesis of Cold Antihydrogen in a Cusp Trap

    SciTech Connect

    Enomoto, Y.; Nagata, Y.; Kanai, Y.; Mohri, A.; Kuroda, N.; Kim, C. H.; Torii, H. A.; Fujii, K.; Ohtsuka, M.; Tanaka, K.; Matsuda, Y.; Michishio, K.; Nagashima, Y.; Higaki, H.; Corradini, M.; Leali, M.; Lodi-Rizzini, E.; Mascagna, V.; Venturelli, L.; Zurlo, N.

    2010-12-10

    We report here the first successful synthesis of cold antihydrogen atoms employing a cusp trap, which consists of a superconducting anti-Helmholtz coil and a stack of multiple ring electrodes. This success opens a new path to make a stringent test of the CPT symmetry via high precision microwave spectroscopy of ground-state hyperfine transitions of antihydrogen atoms.

  2. 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.

  3. 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.

  4. 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.

  5. 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. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Applications of microfluidics and microchip electrophoresis for potential clinical biomarker analysis.

    PubMed

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

    2015-09-01

    This article reviews advances over the last five years in microfluidics and microchip-electrophoresis techniques for detection of clinical biomarkers. The variety of advantages of miniaturization compared with conventional benchtop methods for detecting biomarkers has resulted in increased interest in developing cheap, fast, and sensitive techniques. We discuss the development of applications of microfluidics and microchip electrophoresis for analysis of different clinical samples for pathogen identification, personalized medicine, and biomarker detection. We emphasize the advantages of microfluidic techniques over conventional methods, which make them attractive future diagnostic tools. We also discuss the versatility and adaptability of this technology for analysis of a variety of biomarkers, including lipids, small molecules, carbohydrates, nucleic acids, proteins, and cells. Finally, we conclude with a discussion of aspects that need to be improved to move this technology towards routine clinical and point-of-care applications.

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. Towards disposable lab-on-a-chip: poly(methylmethacrylate) microchip electrophoresis device with electrochemical detection.

    PubMed

    Wang, Joseph; Pumera, Martin; Chatrathi, Madhu Prakash; Escarpa, Alberto; Konrad, Renate; Griebel, Anja; Dörner, Wolfgang; Löwe, Holger

    2002-02-01

    A fully disposable microanalytical device based on combination of poly(methylmethacrylate) (PMMA) capillary electrophoresis microchips and thick-film electrochemical detector strips is described. Variables influencing the separation efficiency and amperometric response, including separation voltage or detection potential are assessed and optimized. The versatility, simplicity and low-cost advantages of the new design are coupled to an attractive analytical performance, with good precision (relative standard deviation RSD = 1.68% for n = 10). Applicability for assays of mixtures of hydrazine, phenolic compounds, and catecholamines is demonstrated. Such coupling of low-cost PMMA-based microchips with thick-film electrochemical detectors holds great promise for mass production of single-use micrototal analytical systems.

  15. Packing density, permeability, and separation efficiency of packed microchips at different particle-aspect ratios.

    PubMed

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

    2009-01-09

    HPLC microchips are investigated experimentally with respect to packing density, pressure drop-flow rate relation, hydraulic permeability, and separation efficiency. The prototype microchips provide minimal dead volume, on-chip UV detection, and a 75 mm long separation channel with a ca. 50 microm x 75 microm trapezoidal cross-section. A custom-built stainless-steel holder allowed to adopt optimized packing conditions. Separation channels were slurry-packed with 3, 5, and 10 microm-sized spherical, porous C8-silica particles. Differences in interparticle porosity, permeability, and plate height data are analyzed and consistently explained by different microchannel-to-particle size (particle-aspect) ratios and particle size distributions.

  16. 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

  17. 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

  18. 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

  19. 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.

  20. 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. Copyright © 2014 Elsevier B.V. All rights reserved.

  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. 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

  5. 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.

  6. Power-free sequential injection for microchip immunoassay toward point-of-care testing.

    PubMed

    Hosokawa, Kazuo; Omata, Masaki; Sato, Kae; Maeda, Mizuo

    2006-02-01

    This paper presents a simple fluid handling technique for microchip immunoassay. Necessary solutions were sequentially injected into a microchannel by air-evacuated poly(dimethylsiloxane), and were passively regulated by capillary force at the inlet opening. For heterogeneous immunoassay, microchips are potentially useful for reduction of sample consumption and assay time. However, most of the previously reported microchips have limitations in their use because of the needs for external power sources for fluid handling. In this paper, an on-chip heterogeneous immunofluorescence assay without such an external power source is demonstrated. The microchip consisting of poly(dimethylsiloxane) (PDMS) and glass has a simple structure, and therefore is suitable for single-use applications. Necessary solutions were sequentially injected into a microchannel in an autonomous fashion with the power-free pumping technique, which exploits the high solubility and the rapid diffusion of air in PDMS. For deionized water, this method yielded flow rates of 3-5 nL s-1 with reproducibility of 4-10%. The inlet opening of the microchannel functioned as a passive valve to hold the solution when the flow was finished. Rabbit immunoglobulin G (rIgG) and human C-reactive protein (CRP) were detected using the microchannel walls as reaction sites. With the sample consumption of 1 microL and the assay time of approximately 20 min including the antibody immobilization step, the sandwich immunoassay methods for rIgG and CRP exhibited the limits of detection of 0.21 nM (0.21 fmol) and 0.42 nM (0.42 fmol), respectively.

  7. 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.

  8. 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.

  9. Multi-watt passively Q-switched Yb:YAB/Cr:YAG microchip lasers

    NASA Astrophysics Data System (ADS)

    Serres, Josep Maria; Loiko, Pavel; Mateos, Xavier; Liu, Junhai; Zhang, Huaijing; Yumashev, Konstantin; Griebner, Uwe; Petrov, Valentin; Aguiló, Magdalena; Díaz, Francesc

    2017-02-01

    A trigonal 5.6 at.% Yb:YAl3(BO3)4 (Yb:YAB) crystal is employed in continuous-wave (CW) and passively Q-switched microchip lasers pumped by a diode at 978 nm. Using a 3 mm-thick, c-cut Yb:YAB crystal, which has a higher pump absorption efficiency, efficient CW microchip laser operation is demonstrated. This laser generated a maximum output power of 7.18 W at 1041-1044 nm with a slope efficiency η of 67% (with respect to the absorbed pump power) and an almost diffraction-limited beam, M2 x,y < 1.1. Inserting a Cr:YAG saturable absorber, stable passive Q-switching of the Yb:YAB microchip laser was obtained. The maximum average output power from the Yb:YAB/Cr:YAG laser reached 2.82 W at 1042 nm with η = 53% and a conversion efficiency with respect to the CW mode of 65% (when using a 0.7 mm-thick Cr:YAG). The latter corresponded to a pulse duration and energy of 7.1 ns / 47 μJ at a pulse repetition rate (PRR) of 60 kHz. Using a 1.3 mm-thick Cr:YAG, 2.02 W were achieved at 1041 nm corresponding to η = 38%. The pulse characteristics were 4.9 ns / 83 μJ at PRR = 24.3 kHz and the maximum peak power reached 17 kW. Yb:YAB crystals are very promising for compact sub-ns power-scalable microchip lasers.

  10. 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. Copyright 2009 Wiley Periodicals, Inc.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Precise determination of N-acetylcysteine in pharmaceuticals by microchip electrophoresis.

    PubMed

    Rudašová, Marína; Masár, Marián

    2016-01-01

    A novel microchip electrophoresis method for the rapid and high-precision determination of N-acetylcysteine, a pharmaceutically active ingredient, in mucolytics has been developed. Isotachophoresis separations were carried out at pH 6.0 on a microchip with conductivity detection. The methods of external calibration and internal standard were used to evaluate the results. The internal standard method effectively eliminated variations in various working parameters, mainly run-to-run fluctuations of an injected volume. The repeatability and accuracy of N-acetylcysteine determination in all mucolytic preparations tested (Solmucol 90 and 200, and ACC Long 600) were more than satisfactory with the relative standard deviation and relative error values <0.7 and <1.9%, respectively. A recovery range of 99-101% of N-acetylcysteine in the analyzed pharmaceuticals predetermines the proposed method for accurate analysis as well. This work, in general, indicates analytical possibilities of microchip isotachophoresis for the quantitative analysis of simplified samples such as pharmaceuticals that contain the analyte(s) at relatively high concentrations. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Integration of a reconstituted cell-free protein-synthesis system on a glass microchip.

    PubMed

    Tanaka, Yo; Shimizu, Yoshihiro

    2015-01-01

    Recently, a cell-free protein synthesis system reconstituted solely from essential elements of the Escherichia coli translation system, termed protein synthesis using recombinant elements (PURE), has been widely used in synthetic biology to analyze fundamental life systems. Here, the system was integrated on a glass microchip system to construct a simple protein synthesis system. GFP template DNAs were immobilized on Sepharose microbeads by streptavidin-biotin binding. The beads were introduced into a Y-shaped microchannel in a glass microchip with a 10-μm height dam structure, and a PURE system reaction mixture was flowed through the microchannel. The recovered solutions had a higher fluorescent intensity than that of the reaction mixture before its introduction into the microchannel, thus verifying that GFP synthesis had been achieved. The microchip with DNA immobilized microbeads is reusable. This is advantageous over a conventional in vitro protein synthesis protocol requiring the preparation and addition of template DNA or mRNA into the reaction mixtures in aspect of simpleness and rapidness.

  17. High-resolution pluronic-filled microchip CE-SSCP analysis system via channel width control.

    PubMed

    Shin, Giyoung; Kim, Dong-Kyun; Doh, Junsang; Lee, Daeyeon; Lee, Nam Ki; Jung, Gyoo Yeol

    2016-02-01

    Although the resolution of CE-SSCP has been significantly improved by using a poly(ethyleneoxide)-poly(propyleneoxide)-poly(ethyleneoxide) (PEO-PPO-PEO; Pluronic(®)) triblock copolymer as a separation medium, CE-SSCP on a microchip format is not widely applicable because their resolution is limited by short channel length. Therefore, a strategy to improve the resolution in channels of limited lengths is highly required for enabling microchip-based CE-SSCP. In this study, we developed a high-resolution CE-SSCP microchip system by controlling the width of the pluronic-filled channel. We tested four different channel widths of 180, 240, 300, and 400 μm, and found that 300 μm showed the highest resolution in the separation of two pathogen specific markers. Potential applications of our method in various genetic analyses were also shown by using SNP markers for spinal muscular atrophy. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. 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. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Investigation of absorption saturation in diode end-pumped microchip lasers

    SciTech Connect

    Cai, Z.; Chardon, A.; Sanchez, F.; Stephan, G.

    1996-12-31

    Two sorts of microchip laser materials, such as Nd:YVO{sub 4} and Er/Yb:Cr phosphate Kigre glass, are used to perform the experimental study of pump absorption saturation. A spatial-dependent rate equation model has been developed for the simulation, and hence the corresponding absorption saturation intensities are determined, the pump saturation intensity is 840 W/cm{sup 2} in the {pi}-polarization, and 2,200 W/cm{sup 2} in the {sigma}-polarization for the 3% a-cut Nd:YVO{sub 4} crystal for the 810nm pump wavelength, and 130 kW/cm{sup 2} for Er/Yb:Cr phosphate Kigre glass for the 975nm pump wavelength. Based on this nonlinear absorption effect, a high performance LD end-pumped Nd:YVO{sub 4} microchip laser was obtained with a low pump threshold of 3 mW and a high slope efficiency of 50%, while for Er/Yb:Cr phosphate Kigre glass laser, a low pump threshold of 5mW and 20% slope efficiency was obtained when pumped by a Ti:Sapphire laser. All the laser operated in a single transverse mode, and the 1.535{micro}m laser operated at a single longitudinal mode. This study gives a useful guideline to design and to optimize the pump beam radius of LD end-pumped microchip lasers.

  20. Microchip electrophoresis with electrochemical detection for the determination of analytes in the dopamine metabolic pathway

    PubMed Central

    Saylor, Rachel A.; Reid, Erin A.; Lunte, Susan M.

    2016-01-01

    A method for the separation and detection of analytes in the dopamine metabolic pathway was developed using microchip electrophoresis with electrochemical detection. The microchip consisted of a 5 cm PDMS separation channel in a simple-t configuration. Analytes in the dopamine metabolic pathway were separated using a background electrolyte composed of 15 mM phosphate at pH 7.4, 15 mM SDS, and 2.5 mM boric acid. Two different microchip substrates using different electrode materials were compared for the analysis: a PDMS/PDMS device with a carbon fiber electrode and a PDMS/glass hybrid device with a pyrolyzed photoresist film carbon electrode. While the PDMS/PDMS device generated high separation efficiencies and good resolution, more reproducible migration times were obtained with the PDMS/glass hybrid device, making it a better choice for biological applications. Lastly, the optimized method was used to monitor L-DOPA metabolism in a rat brain slice. PMID:25958983

  1. Sensitivity enhancing injection from a sample reservoir and channel interface in microchip electrophoresis.

    PubMed

    Wuethrich, Alain; Quirino, Joselito P

    2017-02-01

    The stacking of a cationic analyte (i.e., rhodamine B) at the interface between a sample reservoir and channel in a microchip electrophoresis device is described for the first time. Stacking at negative polarity was by micelle to solvent stacking where the dye was prepared in a micellar solution (5 mM sodium dodecyl sulfate in 25 mM phosphoric acid, pH 2.5) and the channel was filled with high methanol content background solution (70% methanol in 50 mM phosphoric acid, pH 2.5). The injection of the stacked dye into the channel was by simple reversal of the voltage polarity with the sample solution and background solution at the anodic and cathodic reservoirs of the straight channel, respectively. The enrichment of rhodamine B at the interface and injection of the stacked dye into the channel was clearly visualized using an inverted fluorescence microscope. A notable sensitivity enhancement factor of up to 150 was achieved after 2 min at 1 kV of micelle to solvent stacking. The proposed technique will be useful as a concentration step for analyte mixtures in simple and classical cross-channel microchip electrophoresis devices or for the controlled delivery of enriched reagents or analytes as narrow plugs in advanced microchip electrophoresis devices. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Integration of serpentine channels for microchip electrophoresis with a palladium decoupler and electrochemical detection

    PubMed Central

    Bowen, Amanda L; Martin, R. Scott

    2010-01-01

    While it has been shown that microchip electrophoresis with electrochemical detection can be used to separate and detect electroactive species, there is a need to increase the separation performance of these devices so that complex mixtures can be routinely analyzed. Previous work in microchip electrophoresis has demonstrated that increasing the separation channel length leads to an increase in resolution between closely eluting analytes. This paper details the use of lengthened serpentine microchannels for microchip electrophoresis and electrochemical detection where a palladium decoupler is used to ground the separation voltage so that the working electrodes remain in the fluidic network. In this work, palladium electrodepositions were used to increase the decoupler surface area and more efficiently dissipate hydrogen produced at the decoupler. Dopamine and norepinephrine, which only differ in structure by a hydroxyl group, were used as model analytes. It was found that increasing the separation channel length led to improvements in both resolution and the number of theoretical plates for these analytes. The use of a bi-layer valving device, where PDMS-based valves are utilized for the injection process, along with serpentine microchannels and amperometric detection resulted in a multi-analyte separation and an average of 28,700 theoretical plates. It was also shown that the increased channel length is beneficial when separating and detecting analytes from a high ionic strength matrix. This was demonstrated by monitoring the stimulated release of neuro-transmitters from a confluent layer of PC 12 cells. PMID:19739137

  3. Immobilization of trypsin on silica-coated fiberglass core in microchip for highly efficient proteolysis.

    PubMed

    Liu, Ting; Wang, Sheng; Chen, Gang

    2009-03-15

    In this report, trypsin was immobilized on silica-coated fiberglass core in microchip to form a core-changeable bioreactor for highly efficient proteolysis. To prepare the fiber core, a layer of organic-inorganic hybrid silica coating was prepared on the surface of a piece of glass fiber by a sol-gel method with tetraethoxysilane (TEOS) and 3-aminopropyltriethoxysilane (APTES) as precursors. Subsequently, trypsin was immobilized on the coating with the aid of glutaraldehyde. Prior to use, the enzyme-immobilized fiber was inserted into the channel of a microchip to form an in-channel fiber bioreactor. The novel bioreactor can be regenerated by changing its fiber core. The scanning electron microscopy images of the cross-section of a trypsin-immobilized fiber indicated that a layer of approximately 1mum thick film formed on the glass substrate. The feasibility and performance of the unique bioreactor were demonstrated by the tryptic digestion of bovine serum albumin (BSA) and cytochrome c (Cyt-c) and the digestion time was significantly reduced to less than 10s. The digests were identified by MALDI-TOF MS with sequence coverages of 45% (BSA) and 77% (Cyt-c) that were comparable to those obtained by 12-h conventional in-solution tryptic digestion. The fiber-based microchip bioreactor provides a promising platform for the high-throughput protein identification.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. Microchip electrophoresis with electrochemical detection for the determination of analytes in the dopamine metabolic pathway.

    PubMed

    Saylor, Rachel A; Reid, Erin A; Lunte, Susan M

    2015-08-01

    A method for the separation and detection of analytes in the dopamine metabolic pathway was developed using microchip electrophoresis with electrochemical detection. The microchip consisted of a 5 cm PDMS separation channel in a simple-t configuration. Analytes in the dopamine metabolic pathway were separated using a background electrolyte composed of 15 mM phosphate at pH 7.4, 15 mM SDS, and 2.5 mM boric acid. Two different microchip substrates using different electrode materials were compared for the analysis: a PDMS/PDMS device with a carbon fiber electrode and a PDMS/glass hybrid device with a pyrolyzed photoresist film carbon electrode. While the PDMS/PDMS device generated high separation efficiencies and good resolution, more reproducible migration times were obtained with the PDMS/glass hybrid device, making it a better choice for biological applications. Lastly, the optimized method was used to monitor l-DOPA metabolism in a rat brain slice. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. 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.

  12. Holographic optical trapping

    SciTech Connect

    Grier, David G.; Roichman, Yael

    2006-02-10

    Holographic optical tweezers use computer-generated holograms to create arbitrary three-dimensional configurations of single-beam optical traps that are useful for capturing, moving, and transforming mesoscopic objects. Through a combination of beam-splitting, mode-forming, and adaptive wavefront correction, holographic traps can exert precisely specified and characterized forces and torques on objects ranging in size from a few nanometers to hundreds of micrometers. Offering nanometer-scale spatial resolution and real-time reconfigurability, holographic optical traps provide unsurpassed access to the microscopic world and have found applications in fundamental research, manufacturing, and materials processing.

  13. Holographic optical trapping.

    PubMed

    Grier, David G; Roichman, Yael

    2006-02-10

    Holographic optical tweezers use computer-generated holograms to create arbitrary three-dimensional configurations of single-beam optical traps that are useful for capturing, moving, and transforming mesoscopic objects. Through a combination of beam-splitting, mode-forming, and adaptive wavefront correction, holographic traps can exert precisely specified and characterized forces and torques on objects ranging in size from a few nanometers to hundreds of micrometers. Offering nanometer-scale spatial resolution and real-time reconfigurability, holographic optical traps provide unsurpassed access to the microscopic world and have found applications in fundamental research, manufacturing, and materials processing.

  14. [Applications of microchip electrophoresis and capillary electrophoresis for screening FLT3-ITD gene mutation in acute myeloid leukemia].

    PubMed

    Leng, Xin; Li, Ling-Di; Li, Jin-Lan; Huang, Xiao-Jun; Ruan, Guo-Rui

    2014-02-01

    The purpose of the present study was to compare the reliability of microchip electrophoresis and capillary electrophoresis for screening FLT3-ITD gene mutation in acute myeloid leukemia. The FLT3-ITD mutation in the genomic DNA samples from 214 untreated AML patients were separately detected by PCR-microchip electrophoresis and PCR-capillary electrophoresis, then the DNA direct sequencing analysis was carried out. The results from PCR-microchip electrophoresis showed that there were 151 FLT3-ITD mutation negative, 58 FLT3-ITD mutation positive (58/214, 27.1%) and 5 FLT3-ITD mutation doubtful positive (5/214, 2.3%), while the outcomes from PCR-capillary electrophoresis displayed that there were 147 FLT3-ITD mutation negative and 67 FLT3-ITD mutation positive (67/214, 31.3%) without doubtful positive. In the 67 FLT3-ITD mutation positive samples detected by using PCR-capillary electrophoresis, 4 samples were detected as the negative while 5 samples were measured as the doubtful positive by using PCR-microchip electrophoresis. The followed sequencing analysis demonstrated that the above 9 samples were all FLT3-ITD mutation positive, indicating that PCR-capillary electrophoresis was more accurate and sensitive in screening the FLT3-ITD mutation, although statistic analysis showed that there were no significant differences in the detected results between PCR-microchip electrophoresis and PCR-capillary electrophoresis groups (Pearson Chi-squared Test, P > 0.05). It is concluded that both PCR-microchip electrophoresis and PCR-capillary electrophoresis were convenient and fast for screening FLT3-ITD mutation, but the accuracy of PCR-microchip electrophoresis awaits further improvement.

  15. 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.

  16. Rings Through Atmosphere

    NASA Image and Video Library

    2010-05-26

    NASA Cassini spacecraft looks toward the limb of Saturn and, on the right of this image, views part of the rings through the planet atmosphere. Saturn atmosphere can distort the view of the rings from some angles.

  17. Wavy, Wiggly Ring

    NASA Image and Video Library

    2012-04-23

    The constant change in Saturn wavy, wiggly F ring is on display in this image obtained by NASA Cassini spacecraft. The image shows a view looking directly down onto the ring with the planet removed from the center.

  18. Saturn Rings in Infrared

    NASA Image and Video Library

    2006-10-11

    This mosaic of Saturn rings was acquired by NASA Cassini visual and infrared mapping spectrometer instrument on Sept. 15, 2006, while the spacecraft was in the shadow of the planet looking back towards the rings

  19. The Inner Rings

    NASA Image and Video Library

    2007-02-01

    The Cassini spacecraft looks toward the innermost region of Saturn rings, capturing from right to left the C and B rings. The dark, inner edge of the Cassini Division is just visible in the lower left corner

  20. 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.

  1. 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.

  2. 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

  3. 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

  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. 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.

  6. 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.

  7. Modules over hereditary rings

    SciTech Connect

    Tuganbaev, A A

    1998-04-30

    Let A be a hereditary Noetherian prime ring that is not right primitive. A complete description of {pi}-injective A-modules is obtained. Conditions under which the classical ring of quotients of A is a {pi}-projective A-module are determined. A criterion for a right hereditary right Noetherian prime ring to be serial is obtained.

  8. 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)

  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. Eyeing the E Ring

    NASA Image and Video Library

    2009-12-24

    NASA Cassini spacecraft takes a look at Saturn diffuse E ring which is formed from icy material spewing out of the south pole of the moon Enceladus. The E ring is seen nearly edge-on from slightly above the northern side of Saturn ring plane.

  11. 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…

  12. 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…

  13. 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

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. Role of interfering optical fields in the trapping and melting of gold nanorods and related clusters.

    PubMed

    Deng, Hai-Dong; Li, Guang-Can; Dai, Qiao-Feng; Ouyang, Min; Lan, Sheng; Gopal, Achanta Venu; Trofimov, Vyacheslav A; Lysak, Tatiana M

    2012-05-07

    We investigate the simultaneous trapping and melting of a large number of gold (Au) nanorods by using a single focused laser beam at 800 nm which is in resonance with the longitudinal surface plasmon resonance of Au nanorods. The trapping and melting processes were monitored by the two-photon luminescence of Au nanorods. A multi-ring-shaped pattern was observed in the steady state of the trapping process. In addition, optical trapping of clusters of Au nanorods in the orbits circling the focus was observed. The morphology of the structure after trapping and melting of Au nanorods was characterized by scanning electron microscope. It was revealed that Au nanorods were selectively melted in the trapping region. While Au nanorods distributed in the dark rings were completely melted, those located in the bright rings remain unmelted. The multi-ring-shaped pattern formed by the interference between the incident light and the scattered light plays an important role in the trapping and melting of Au nanorods.

  20. Preparation of a Surface-functionalized Power-free PDMS Microchip for MicroRNA Detection Utilizing Electron Beam-induced Graft Polymerization.

    PubMed

    Ishihara, Ryo; Uchino, Yoshitaka; Hosokawa, Kazuo; Maeda, Mizuo; Kikuchi, Akihiko

    2017-01-01

    We propose an easy microchannel surface functionalization method for a poly(dimethylsiloxane) (PDMS) microchip that utilizes electron beam-induced graft polymerization (EIGP) as a platform for microchip-based biomarker analysis. Unlike other grafting techniques, EIGP enables rapid surface modification of PDMS without initiator immobilization. The grafted microchip is preservable, and can be easily functionalized for versatile applications. In this study, the surface-functionalized power-free microchip (SF-PF microchip) was used for the detection of microRNA (miRNA), which is a biomarker for many serious diseases. The EIGP enables high-density three-dimensional probe DNA immobilization, resulting in rapid and sensitive miRNA detection on the portable SF-PF microchip. The limit of detection was 0.8 pM, the required sample volume was 0.5 μL, and the analysis time was 15 min. The SF-PF microchip will be a versatile platform for microchip-based point-of-care diagnosis.