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Sample records for conjugate fracture pairs

  1. Conjugate fracture pairs in the Molina Member of the Wasatch Formation, Piceance basin, Colorado: Implications for fracture origins and hydrocarbon production/exploration

    SciTech Connect

    Lorenz, J.C.

    1997-05-01

    The sandstones of the Molina Member of the Wasatch Formation in the Piceance basin of northwestern Colorado contain a suite of fractures that have a conjugate-pair geometry. The fractures are vertical and intersect at an acute angle of between 20 and 40 degrees. Although direct evidence of shear is rare, the fracture surfaces commonly display small steps. The fracture geometries suggest that the maximum compressive stress during fracturing was in the plane of the acute angle of the conjugate fractures: the steps are interpreted as broken-face manifestations of very low angle en echelon fractures, formed within exceptionally narrow zones of incipient shear. In contrast to the highly anisotropic permeability enhancement created by subparallel vertical extension fractures in the underlying Mesaverde Formation, the conjugate pairs in the Molina sandstones should create a well connected and relatively isotropic mesh of fracture conductivity. Increases in stress magnitudes and anisotropy during production drawdown of reservoir pressures should cause shear offsets along the fractures, initially enhancing permeability.

  2. Conformal algebra on Fock space and conjugate pairs of operators

    SciTech Connect

    Sibold, Klaus; Burkhard, Eden

    2010-11-15

    Using the moment construction, we represent the generators of the conformal algebra as bilinear products of creation and annihiliation operators on the Fock space of the massless real scalar field in four dimensions. A complete set of one-particle eigenstates of the dilatation generator is given. Next, a complete set of one-particle eigenstates of the conformal generator is constructed in two distinct ways, once directly and once through an expansion in terms of dilatation eigenstates. The second approach uses an analytic continuation of the dilatation eigenvalue away from the real axis; the validity of the method is illustrated by the consistency with the first approach. Drawing upon this technique, we finally ponder the idea of building conjugates to the four components of the momentum operator by suitably modifying the action of the conformal generators on dilatation eigenstates. The construction of eigenstates of these new operators proceeds as for the conformal generator itself.

  3. Membrane protein crystallization in micelles conjugated by nucleoside base-pairing: A different concept.

    PubMed

    Hosamani, Basavaprabhu; Kale, Raju R; Sharma, Hemlata; Wachtel, Ellen; Kesselman, Ellina; Danino, Dganit; Friedman, Noga; Sheves, Mordechai; Namboothiri, Irishi N N; Patchornik, Guy

    2016-09-01

    The dearth of high quality, three dimensional crystals of membrane proteins, suitable for X-ray diffraction analysis, constitutes a serious barrier to progress in structural biology. To address this challenge, we have developed a new crystallization medium that relies on the conjugation of surfactant micelles via base-pairing of complementary hydrophobic nucleosides. Base-pairs formed at the interface between micelles bring them into proximity with each other; and when the conjugated micelles contain a membrane protein, crystal nucleation centers can be stabilized, thereby promoting crystal growth. Accordingly, two hydrophobic nucleoside derivatives - deoxyguanosine (G) and deoxycytidine (C), each covalently bonded to a 10 carbon chain were synthesized and added to an aqueous solution containing octyl β-d-thioglucopyranoside micelles. These hydrophobic nucleosides induced the formation of oil-rich globules after 2days incubation at 19°C or after a few hours in the presence of ammonium sulfate; however, phase separation was inhibited by 100mM GMP. The presence of the membrane protein bacteriorhodopsin in the conjugated - micellar dispersion resulted in the growth within the colorless globules of a variety of purple crystals, the color indicating a functional protein. On this basis, we suggest that conjugation of micelles via base-pair complementarity may provide significant assistance to the structural determination of integral membrane proteins. PMID:27368128

  4. Interplay between proton-neutron pairing and deformation in self-conjugated medium mass nuclei

    NASA Astrophysics Data System (ADS)

    Gambacurta, Danilo; Lacroix, Denis

    2016-05-01

    We employ a model combining self-consistent mean-field and shell model techniques to study the competition between particle-like and proton-neutron pairing correlations in fp-shell even-even self-conjugate nuclei. Deformation effects are realistically and microscopically described. The resulting approach can give a precise description of pairing correlations and eventually treat the coexistence of different condensate formed of pairs with different total spin/ isospin. The standard BCS calculations are systematically compared with approaches including correlation effects beyond the independent quasi-particle picture. The competition between proton-neutron correlations in the isoscalar and isovector channels is also analyzed, as well as their dependence on the deformation properties.

  5. Two canonical conjugate pairs at the horizon of a D 1 D 5 black hole

    NASA Astrophysics Data System (ADS)

    Hadad, Merav; Rosenblum, Levy

    2015-12-01

    The Euclidean opening angle at the r -tE surface, Θr -tE at the horizon of a black hole, is canonically conjugate to the black hole entropy. We prove that for a D 1 D 5 black hole there exists in addition to this pair, another canonical pair: the opening angle at the r -y surface, Θr -y, and a Wald-like term SW r -y. This leads to an uncertainty at Θr -y which suggests that the surface r -y is actually a superposition of surfaces with different conical singularities. This corresponds to the same type of singularities obtained by string theory excitations of a D 1 D 5 black hole.

  6. On the validity of the conjugate pairing rule for Lyapunov exponents

    SciTech Connect

    Bonetto, F.; Cohen, E.G.D.; Pugh, C.

    1998-08-01

    For Hamiltonian systems subject to an external potential which in the presence of a thermostat will reach a nonequilibrium stationary state Dettmann and Morriss proved a strong conjugate pairing rule (SCPR) for pairs of Lyapunov exponents in the case of isokinetic (IK) stationary states which have a given kinetic energy. This SCPR holds for all initial phases of the system, all times t, and all numbers of particles N. This proof was generalized by Wojtkowski and Liverani to include hard interparticle potentials. A geometrical reformulation of those results is presented. The present paper proves numerically, using periodic orbits for the Lorentz gas, that SCPR cannot hold for isoenergetic (IE) stationary states which have a given total internal energy. In that case strong evidence is obtained for CPR to hold for large N and t, where it can be conjectured that the larger N, the smaller t will be. This suffices for statistical mechanics.

  7. Deep seismic studies of conjugate profiles from the Nova Scotia - Moroccan and the Liguro-Provencal margin pairs

    NASA Astrophysics Data System (ADS)

    Klingelhoefer, F.; Biari, Y.; Sahabi, M.; Aslanian, D.; Philippe, S.; Schnabel, M.; Moulin, M.; Louden, K. E.; Funck, T.; Reichert, C. J.

    2014-12-01

    The structure of conjugate passive margins provides information about rifting styles, opening of an ocean and formation of it's associated sedimentary basins. In order to distinguish between tectonic inheritance and structures directly related to rifting of passive margins conjugate profiles have to be acquired on margins on diverse locations and different ages. In this study we use new and existing reflection and wide-angle seismic data from two margin pairs, the 200 Ma year old Nova-Scotia - Morocco margin pair and the only 20 Ma Gulf of Lions - Sardinia margin pair. On both margin pairs wide-angle seismic data combined with reflection seismic data were acquired on conjugate profiles on sea and extended on land. Forward modelling of the deep crustal structure along the four transects indicates that a high velocity zone (HVZ) (> 7.2 km/s) is present at the base of the lower crust on all four margins along the ocean-continental transition zone (OCT). This may represent either exhumed upper mantle material or injection of upper mantle material into proto-oceanic crust at the onset of sea-floor spreading. However the width of the HVZ might strongly differ between conjugates, which may be the result of tectonic inheritance, for example the presence of ancient subduction zones or orogens. Both margin pairs show a similar unthinned continental crustal thickness. Crustal thinning and upper-to-lower crustal thickness vary between margin pairs, but remain nearly symmetric on conjugate profiles and might therefore depend on the structure and mechanical properties of the original continental crust. For the Mediterranean margin pair, the oceanic crust is similar on both sides, with a thickness of only 4-5 km. For the Atlantic margin pair, oceanic crustal thickness is higher on the Moroccan Margin, a fact that can be explained by either asymmetric spreading or by the volcanic underplating, possibly originating from the Canary Hot Spot.

  8. Computer simulation of fracture using long range pair potentials

    NASA Technical Reports Server (NTRS)

    Mullins, M.

    1984-01-01

    The behavior of a crack in iron is studied using computer simulation. A Morse interatomic potential is used which is of a longer ranged nature than the potentials used in previous studies. With this potential, blunting of the crack tip by spontaneous dislocation nucleation occurs under most conditions. The presence of hydrogen appears to inhibit this blunting and thus to encourage brittle fracture. In the absence of hydrogen, a temperature dependent brittle-ductile transition is observed for some loads. This behavior is quite different from that observed when shorter ranged potentials are used, and it appears to be in somewhat better agreement with experimental results. This agreement with experiment is not conclusive, however, indicating the need for further work to determine more accurate potentials.

  9. Kinetics and fracture resistance of lithiated silicon nanostructure pairs controlled by their mechanical interaction

    SciTech Connect

    Lee, Seok Woo; Lee, Hyun -Wook; Ryu, Ill; Nix, William D.; Gao, Huajian; Cui, Yi

    2015-06-26

    Following an explosion of studies of silicon as a negative electrode for Li-ion batteries, the anomalous volumetric changes and fracture of lithiated single Si particles have attracted significant attention in various fields, including mechanics. However, in real batteries, lithiation occurs simultaneously in clusters of Si in a confined medium. Hence, understanding how the individual Si structures interact during lithiation in a closed space is necessary. Here, we demonstrate physical and mechanical interactions of swelling Si structures during lithiation using well-defined Si nanopillar pairs. Ex situ SEM and in situ TEM studies reveal that compressive stresses change the reaction kinetics so that preferential lithiation occurs at free surfaces when the pillars are mechanically clamped. Such mechanical interactions enhance the fracture resistance of lithiated Si by lessening the tensile stress concentrations in Si structures. Lastly, this study will contribute to improved design of Si structures at the electrode level for high-performance Li-ion batteries.

  10. Kinetics and fracture resistance of lithiated silicon nanostructure pairs controlled by their mechanical interaction

    PubMed Central

    Lee, Seok Woo; Lee, Hyun-Wook; Ryu, Ill; Nix, William D.; Gao, Huajian; Cui, Yi

    2015-01-01

    Following an explosion of studies of silicon as a negative electrode for Li-ion batteries, the anomalous volumetric changes and fracture of lithiated single Si particles have attracted significant attention in various fields, including mechanics. However, in real batteries, lithiation occurs simultaneously in clusters of Si in a confined medium. Hence, understanding how the individual Si structures interact during lithiation in a closed space is necessary. Here, we demonstrate physical and mechanical interactions of swelling Si structures during lithiation using well-defined Si nanopillar pairs. Ex situ SEM and in situ TEM studies reveal that compressive stresses change the reaction kinetics so that preferential lithiation occurs at free surfaces when the pillars are mechanically clamped. Such mechanical interactions enhance the fracture resistance of lithiated Si by lessening the tensile stress concentrations in Si structures. This study will contribute to improved design of Si structures at the electrode level for high-performance Li-ion batteries. PMID:26112834

  11. Ionospheric total electron content behavior at a pair of mid-latitude conjugate stations

    NASA Astrophysics Data System (ADS)

    Essex, E. A.; Klobuchar, J. A.

    1981-07-01

    A correlation study of the geomagnetic conjugate effects in the ionospheric total electron content carried out between Shemya, Alaska and Beveridge, Australia is discussed. In the study, the seasonal, diurnal, and magnetic activity dependence of the correlation is determined. It is found that for equinoxes during low magnetic activity the correlation is positive during local afternoon and negative during local night to local morning hours. For the early winter-summer conjugate study, the correlation is for the most part positive during the local daytime and negative during local nighttime. For later winter-summer, the correlation is for the most part low, oscillating about zero throughout the day. With higher magnetic activity, the correlation is generally positive throughout the day during equinoxes, dropping below zero for about 3 hours around local sunrise. A similar result is true for later winter-summer. However, early winter-summer shows significant positive correlation only during local afternoon hours. An investigation of equinoctial and winter-summer geomagnetically conjugate storm effects shows that while equinoctial storm effects can occur simultaneously in both hemispheres, the seasonal differences between winter and summer storms tend to dominate during solstice storms.

  12. Kinetics and fracture resistance of lithiated silicon nanostructure pairs controlled by their mechanical interaction

    SciTech Connect

    Lee, Seok Woo; Lee, Hyun-Wook; Ryu, Ill; Nix, William D.; Gao, Huajian; Cui, Yi; /Stanford U., Materials Sci. Dept. /SLAC

    2015-06-01

    Following an explosion of studies of silicon as a negative electrode for Li-ion batteries, the anomalous volumetric changes and fracture of lithiated single Si particles have attracted significant attention in various fields, including mechanics. However, in real batteries, lithiation occurs simultaneously in clusters of Si in a confined medium. Hence, understanding how the individual Si structures interact during lithiation in a closed space is necessary. Herein, we demonstrate physical/mechanical interactions of swelling Si structures during lithiation using well-defined Si nanopillar pairs. Ex situ SEM and in situ TEM studies reveal that compressive stresses change the reaction kinetics so that preferential lithiation occurs at free surfaces when the pillars are mechanically clamped. Such mechanical interactions enhance the fracture resistance of This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, under Contract No. DE-AC02-76SF00515. SLAC-PUB-16300 2 lithiated Si by lessening the tensile stress concentrations in Si structures. This study will contribute to improved design of Si structures at the electrode level for high performance Li-ion batteries.

  13. Kinetics and fracture resistance of lithiated silicon nanostructure pairs controlled by their mechanical interaction

    DOE PAGESBeta

    Lee, Seok Woo; Lee, Hyun -Wook; Ryu, Ill; Nix, William D.; Gao, Huajian; Cui, Yi

    2015-06-26

    Following an explosion of studies of silicon as a negative electrode for Li-ion batteries, the anomalous volumetric changes and fracture of lithiated single Si particles have attracted significant attention in various fields, including mechanics. However, in real batteries, lithiation occurs simultaneously in clusters of Si in a confined medium. Hence, understanding how the individual Si structures interact during lithiation in a closed space is necessary. Here, we demonstrate physical and mechanical interactions of swelling Si structures during lithiation using well-defined Si nanopillar pairs. Ex situ SEM and in situ TEM studies reveal that compressive stresses change the reaction kinetics somore » that preferential lithiation occurs at free surfaces when the pillars are mechanically clamped. Such mechanical interactions enhance the fracture resistance of lithiated Si by lessening the tensile stress concentrations in Si structures. Lastly, this study will contribute to improved design of Si structures at the electrode level for high-performance Li-ion batteries.« less

  14. Functionalization of Intramolecular Frustrated Lewis Pairs by 1,1-Carboboration with Conjugated Enynes.

    PubMed

    Feldmann, Andreas; Kehr, Gerald; Daniliuc, Constantin G; Mück-Lichtenfeld, Christian; Erker, Gerhard

    2015-08-24

    The vicinal P/B frustrated Lewis pair (FLP) Mes2PCH2CH2B(C6F5)2 undergoes 1,1-carboboration reactions with the Me3Si-substituted enynes to give ring-enlarged functionalized C3-bridged P/B FLPs. These serve as active FLPs in the activation of dihydrogen to give the respective zwitterionic [P]H(+)/[B]H(-) products. One such product shows activity as a metal-free catalyst for the hydrogenation of enamines or a bulky imine. The ring-enlarged FLPs contain dienylborane functionalities that undergo "bora-Nazarov"-type ring-closing rearrangements upon photolysis. A DFT study had shown that the dienylborane cyclization of such systems itself is endothermic, but a subsequent C6F5 migration is very favorable. Furthermore, substituted 2,5-dihydroborole products are derived from cyclization and C6F5 migration from the photolysis reaction. In the case of the six-membered annulation product, a subsequent stereoisomerization reaction takes place and the resultant compound undergoes a P/B FLP 1,2-addition reaction with a terminal alkyne with rearrangement. PMID:26284948

  15. First results from the SARDINIA deep seismic cruise on the Western Sardinia and Gulf of Lions conjugate margin pair

    NASA Astrophysics Data System (ADS)

    Gailler, A.; Klingelhoefer, F.; Beslier, M.; Olivet, J.; Aslanian, D.; Bache, F.; Moulin, M.; Matias, L.; Afilhado, A.; Nouze, H.

    2008-12-01

    The deep North-Western Mediterranean (or Provencal) basin was formed by thinning and rotation of the Corsica-Sardinia block which started 30-20 Ma ago. It is bounded by the Gulf of Lions to the north, the Catalan margin to the west, the Ligurian Sea to the east, and the Valencia Trough to the south-west, in which rifting started at roughly the same time as in the Provencal basin. The basin has a depth of up to 2.8 km and a sedimentary layer thickness of up to 8 km. The central part of the basin is presumed to be underlain by a crust of oceanic nature, while the neighboring Valencia Trough is situated on thinned continental crust. During the SARDINIA cruise of the R/V Atalante in December 2006, three wide-angle seismic profiles were acquired in the Gulf of Lions area and three profiles on the conjugate margin offshore Sardinia. The main goals of the SARDINIA project were to image the deep structure of the conjugate margin pair, to characterize the nature of the crust, detect any exhumed upper mantle materiel and to define the geometry of the basins to better constrain the opening history of the basin. During the cruise, a total of 57 ocean bottom seismometers/hydrophones (OBS/OBH) from Ifremer, the University of Brest and Geomar, Kiel were deployed in the Gulf of Lions region and 47 OBS and OBH offshore Sardinia. The lines perpendicular to the margins were recorded by landstations onshore, thus prolonging the profiles. Tomographic and forward wide-angle seismic models of the deep seismic data from the margin perpendicular profile located in the Gulf of Lions image a sedimentary layer up to 8 km thickness, which is locally strongly disturbed by salt tectonics. They indicate, that crustal thinning in the Gulf of Lions area occurs within a 100 km wide zone. East of this zone of crustal thinning is a zone characterized by high velocities in the lower crust (7.2-7.4 km/s) atypical for either thinned continental or normal oceanic crust. The boundary of this layer

  16. Fractures

    PubMed Central

    Hall, Michael C.

    1963-01-01

    Recent studies on the epidemiology and repair of fractures are reviewed. The type and severity of the fracture bears a relation to the age, sex and occupation of the patient. Bone tissue after fracture shows a process of inflammation and repair common to all members of the connective tissue family, but it repairs with specific tissue. Cartilage forms when the oxygen supply is outgrown. After a fracture, the vascular bed enlarges. The major blood supply to healing tissue is from medullary vessels and destruction of them will cause necrosis of the inner two-thirds of the cortex. Callus rapidly mineralizes, but full mineralization is achieved slowly; increased mineral metabolism lasts several years after fracture. PMID:13952119

  17. Comparison of Proteins Involved in Pilus Synthesis and Mating Pair Stabilization from the Related Plasmids F and R100-1: Insights into the Mechanism of Conjugation

    PubMed Central

    Anthony, Karen G.; Klimke, William A.; Manchak, Jan; Frost, Laura S.

    1999-01-01

    F and R100-1 are closely related, derepressed, conjugative plasmids from the IncFI and IncFII incompatibility groups, respectively. Heteroduplex mapping and genetic analyses have revealed that the transfer regions are extremely similar between the two plasmids. Plasmid specificity can occur at the level of relaxosome formation, regulation, and surface exclusion between the two transfer systems. There are also differences in pilus serology, pilus-specific phage sensitivity, and requirements for OmpA and lipopolysaccharide components in the recipient cell. These phenotypic differences were exploited in this study to yield new information about the mechanism of pilus synthesis, mating pair stabilization, and surface and/or entry exclusion, which are collectively involved in mating pair formation (Mpf). The sequence of the remainder of the transfer region of R100-1 (trbA to traS) has been completed, and the complete sequence is compared to that of F. The differences between the two transfer regions include insertions and deletions, gene duplications, and mosaicism within genes, although the genes essential for Mpf are conserved in both plasmids. F+ cells carrying defined mutations in each of the Mpf genes were complemented with the homologous genes from R100-1. Our results indicate that the specificity in recipient cell recognition and entry exclusion are mediated by TraN and TraG, respectively, and not by the pilus. PMID:10464182

  18. Fractures

    MedlinePlus

    ... commonly happen because of car accidents, falls, or sports injuries. Other causes are low bone density and osteoporosis, which cause weakening of the bones. Overuse can cause stress fractures, which are very small cracks in the ...

  19. Fractures

    MedlinePlus

    A fracture is a break, usually in a bone. If the broken bone punctures the skin, it is called an open ... falls, or sports injuries. Other causes are low bone density and osteoporosis, which cause weakening of the ...

  20. Probing long-range carrier-pair spin–spin interactions in a conjugated polymer by detuning of electrically detected spin beating

    PubMed Central

    van Schooten, Kipp J.; Baird, Douglas L.; Limes, Mark E.; Lupton, John M.; Boehme, Christoph

    2015-01-01

    Weakly coupled electron spin pairs that experience weak spin–orbit interaction can control electronic transitions in molecular and solid-state systems. Known to determine radical pair reactions, they have been invoked to explain phenomena ranging from avian magnetoreception to spin-dependent charge-carrier recombination and transport. Spin pairs exhibit persistent spin coherence, allowing minute magnetic fields to perturb spin precession and thus recombination rates and photoreaction yields, giving rise to a range of magneto-optoelectronic effects in devices. Little is known, however, about interparticle magnetic interactions within such pairs. Here we present pulsed electrically detected electron spin resonance experiments on poly(styrene-sulfonate)-doped poly(3,4-ethylenedioxythiophene) (PEDOT:PSS) devices, which show how interparticle spin–spin interactions (magnetic-dipolar and spin-exchange) between charge-carrier spin pairs can be probed through the detuning of spin-Rabi oscillations. The deviation from uncoupled precession frequencies quantifies both the exchange (<30 neV) and dipolar (23.5±1.5 neV) interaction energies responsible for the pair's zero-field splitting, implying quantum mechanical entanglement of charge-carrier spins over distances of 2.1±0.1 nm. PMID:25868686

  1. Probing long-range carrier-pair spin-spin interactions in a conjugated polymer by detuning of electrically detected spin beating

    NASA Astrophysics Data System (ADS)

    van Schooten, Kipp J.; Baird, Douglas L.; Limes, Mark E.; Lupton, John M.; Boehme, Christoph

    2015-04-01

    Weakly coupled electron spin pairs that experience weak spin-orbit interaction can control electronic transitions in molecular and solid-state systems. Known to determine radical pair reactions, they have been invoked to explain phenomena ranging from avian magnetoreception to spin-dependent charge-carrier recombination and transport. Spin pairs exhibit persistent spin coherence, allowing minute magnetic fields to perturb spin precession and thus recombination rates and photoreaction yields, giving rise to a range of magneto-optoelectronic effects in devices. Little is known, however, about interparticle magnetic interactions within such pairs. Here we present pulsed electrically detected electron spin resonance experiments on poly(styrene-sulfonate)-doped poly(3,4-ethylenedioxythiophene) (PEDOT:PSS) devices, which show how interparticle spin-spin interactions (magnetic-dipolar and spin-exchange) between charge-carrier spin pairs can be probed through the detuning of spin-Rabi oscillations. The deviation from uncoupled precession frequencies quantifies both the exchange (<30 neV) and dipolar (23.5+/-1.5 neV) interaction energies responsible for the pair's zero-field splitting, implying quantum mechanical entanglement of charge-carrier spins over distances of 2.1+/-0.1 nm.

  2. Nose fracture

    MedlinePlus

    Fracture of the nose; Broken nose; Nasal fracture; Nasal bone fracture; Nasal septal fracture ... A fractured nose is the most common fracture of the face. It ... with other fractures of the face. Sometimes a blunt injury can ...

  3. Nose fracture

    MedlinePlus

    Fracture of the nose; Broken nose; Nasal fracture; Nasal bone fracture; Nasal septal fracture ... A fractured nose is the most common fracture of the face. It usually occurs after an injury and often occurs with ...

  4. Ultrafast Photoinduced Charge Separation Leading to High-Energy Radical Ion-Pairs in Directly Linked Corrole-C60 and Triphenylamine-Corrole-C60 Donor-Acceptor Conjugates.

    PubMed

    Sudhakar, Kolanu; Gokulnath, Sabapathi; Giribabu, Lingamallu; Lim, Gary N; Trâm, Tạ; D'Souza, Francis

    2015-12-01

    Closely positioned donor-acceptor pairs facilitate electron- and energy-transfer events, relevant to light energy conversion. Here, a triad system TPACor-C60 , possessing a free-base corrole as central unit that linked the energy donor triphenylamine (TPA) at the meso position and an electron acceptor fullerene (C60) at the β-pyrrole position was newly synthesized, as were the component dyads TPA-Cor and Cor-C60. Spectroscopic, electrochemical, and DFT studies confirmed the molecular integrity and existence of a moderate level of intramolecular interactions between the components. Steady-state fluorescence studies showed efficient energy transfer from (1) TPA* to the corrole and subsequent electron transfer from (1) corrole* to fullerene. Further studies involving femtosecond and nanosecond laser flash photolysis confirmed electron transfer to be the quenching mechanism of corrole emission, in which the electron-transfer products, the corrole radical cation (Cor(⋅+) in Cor-C60 and TPA-Cor(⋅+) in TPACor-C60) and fullerene radical anion (C60(⋅-)), could be spectrally characterized. Owing to the close proximity of the donor and acceptor entities in the dyad and triad, the rate of charge separation, kCS , was found to be about 10(11)  s(-1), suggesting the occurrence of an ultrafast charge-separation process. Interestingly, although an order of magnitude slower than kCS , the rate of charge recombination, kCR , was also found to be rapid (kCR ≈10(10)  s(-1)), and both processes followed the solvent polarity trend DMF>benzonitrile>THF>toluene. The charge-separated species relaxed directly to the ground state in polar solvents while in toluene, formation of (3) corrole* was observed, thus implying that the energy of the charge-separated state in a nonpolar solvent is higher than the energy of (3) corrole* being about 1.52 eV. That is, ultrafast formation of a high-energy charge-separated state in toluene has been achieved in these closely spaced corrole

  5. Skull fracture

    MedlinePlus

    Basilar skull fracture; Depressed skull fracture; Linear skull fracture ... Skull fractures may occur with head injuries . The skull provides good protection for the brain. However, a severe impact ...

  6. Anti- (conjugate) linearity

    NASA Astrophysics Data System (ADS)

    Uhlmann, Armin

    2016-03-01

    This is an introduction to antilinear operators. In following Wigner the terminus antilinear is used as it is standard in Physics. Mathematicians prefer to say conjugate linear. By restricting to finite-dimensional complex-linear spaces, the exposition becomes elementary in the functional analytic sense. Nevertheless it shows the amazing differences to the linear case. Basics of antilinearity is explained in sects. 2, 3, 4, 7 and in sect. 1.2: Spectrum, canonical Hermitian form, antilinear rank one and two operators, the Hermitian adjoint, classification of antilinear normal operators, (skew) conjugations, involutions, and acq-lines, the antilinear counterparts of 1-parameter operator groups. Applications include the representation of the Lagrangian Grassmannian by conjugations, its covering by acq-lines. As well as results on equivalence relations. After remembering elementary Tomita-Takesaki theory, antilinear maps, associated to a vector of a two-partite quantum system, are defined. By allowing to write modular objects as twisted products of pairs of them, they open some new ways to express EPR and teleportation tasks. The appendix presents a look onto the rich structure of antilinear operator spaces.

  7. Pick a Pair. Pancake Pairs

    ERIC Educational Resources Information Center

    Miller, Pat

    2005-01-01

    Cold February weather and pancakes are a traditional pairing. Pancake Day began as a way to eat up the foods that were abstained from in Lent--traditionally meat, fat, eggs and dairy products. The best-known pancake event is The Pancake Day Race in Buckinghamshire, England, which has been run since 1445. This column describes pairs of books that…

  8. Fracture opening/propagation behavior and their significance on pressure-time records during hydraulic fracturing

    SciTech Connect

    Takashi Kojima; Yasuhiko Nakagawa; Koji Matsuki; Toshiyuki Hashida

    1992-01-01

    Hydraulic fracturing with constant fluid injection rate was numerically modeled for a pair of rectangular longitudinal fractures intersecting a wellbore in an impermeable rock mass, and numerical calculations have been performed to investigate the relations among the form of pressure-time curves, fracture opening/propagation behavior and permeability of the mechanically closed fractures. The results have shown that both permeability of the fractures and fluid injection rate significantly influence the form of the pressure-time relations on the early stage of fracture opening. Furthermore it has been shown that wellbore pressure during fracture propagation is affected by the pre-existing fracture length.

  9. Winning Pairs.

    ERIC Educational Resources Information Center

    Monsour, Florence

    2000-01-01

    Mentoring programs that pair experienced and first-time teachers are gaining prominence in supporting, developing, and retaining new teachers. The successful Beginning Teacher Assistance program at University of Wisconsin-River Falls was designed to give new K-12 teachers the opportunity for yearlong, structured support from mentor teachers. (MLH)

  10. Elbow Fractures

    MedlinePlus

    ... and held together with pins and wires or plates and screws. Fractures of the distal humerus (see ... doctor. These fractures usually require surgical repair with plates and/or screw, unless they are stable. SIGNS ...

  11. Olecranon Fractures.

    PubMed

    Brolin, Tyler J; Throckmorton, Thomas

    2015-11-01

    Olecranon fractures are common upper extremity injuries, with all but nondisplaced fractures treated surgically. There has been a recent shift in the surgical management of these fractures from tension band wiring to locking plate fixation and intramedullary nailing; however, this comes with increased implant cost. Although most patients can expect good outcomes after these various techniques, there is little information to guide a surgeon's treatment plan. This article reviews the epidemiology, classification, treatment, and outcomes of olecranon fractures. PMID:26498547

  12. Sports fractures.

    PubMed Central

    DeCoster, T. A.; Stevens, M. A.; Albright, J. P.

    1994-01-01

    Fractures occur in athletes and dramatically influence performance during competitive and recreational activities. Fractures occur in athletes as the result of repetitive stress, acute sports-related trauma and trauma outside of athletics. The literature provides general guidelines for treatment as well as a variety of statistics on the epidemiology of fractures by sport and level of participation. Athletes are healthy and motivated patients, and have high expectations regarding their level of function. These qualities make them good surgical candidates. Although closed treatment methods are appropriate for most sports fractures, an aggressive approach to more complicated fractures employing current techniques may optimize their subsequent performance. PMID:7719781

  13. Hip fracture - discharge

    MedlinePlus

    Inter-trochanteric fracture repair - discharge; Subtrochanteric fracture repair - discharge; Femoral neck fracture repair - discharge; Trochanteric fracture repair - discharge; Hip pinning surgery - discharge

  14. Extended depth-of-field imaging through radially symmetrical conjugate phase masks

    NASA Astrophysics Data System (ADS)

    Chen, Shouqian; Le, Van Nhu; Fan, Zhigang; Tran, Hong Cam

    2015-11-01

    We proposed a radially symmetrical conjugate phase mask (PM) pair to yield an invariant imaging property for extending depth-of-field imaging. This conjugate PM pair is a two-radially symmetrical phase function with opposite orientation of the phase modulation. Compared with a single-radially symmetrical PM, the proposed conjugate PM pair shows a symmetrically imaging property on both sides of the focal plane and high magnitude of modulation transfer function (MTF). The quartic phase mask (QPM) with optimized phase parameters is employed to demonstrate our concept. Several evaluation approaches, including point-spread function, MTF, and image simulation, are used to realize the performance comparison among a traditional imaging system, an original QPM system, and a conjugate QPM. The results are proof that the proposed conjugate PM has a superior performance in extending depth of field imaging.

  15. Fracture of articular cartilage.

    PubMed

    Chin-Purcell, M V; Lewis, J L

    1996-11-01

    Crack formation and propagation is a significant element of the degeneration process in articular cartilage. In order to understand this process, and separate the relative importance of structural overload and material failure, methods for measuring the fracture toughness of cartilage are needed. In this paper, two such methods are described and used to measure fracture properties of cartilage from the canine patella. A modified single edge notch (MSEN) specimen was used to measure J, and a trouser tear test was used to measure T, both measures of fracture toughness with units of kN/m. A pseudo-elastic modulus was also obtained from the MSEN test. Several potential error sources were examined, and results for the MSEN test compared with another method for measuring the fracture parameter for urethane rubber. Good agreement was found. The two test methods were used to measure properties of cartilage from the patellae of 12 canines: 4-9 specimens from each of 12 patellae, with 5 right-left pairs were tested. Values of J ranged from 0.14-1.2 kN/m. J values correlated with T and were an average of 1.7 times larger than T. A variety of failure responses was seen in the MSEN tests, consequently a grade of 0 to 3 was assigned to each test, where 0 represented a brittle-like crack with minimal opening and 3 represented plastic flow with no crack formation. The initial cracks in 12/82 specimens did not propagate and were assigned to grade 3. The method for reducing data in the MSEN test assumed pseudo-elastic response and could not be used for the grade 3 specimens. Stiffness did not correlate with J. Neither J nor T was statistically different between right-left pairs, but varied between animals. The test methods appear useful for providing a quantitative measure of fracture toughness for cartilage and other soft materials. PMID:8950659

  16. Conjugal amyotrophic lateral sclerosis

    PubMed Central

    Dewitt, John D.; Kwon, Julia; Burton, Rebecca

    2012-01-01

    Amyotrophic lateral sclerosis (ALS) is a disease characterized by progressive degeneration of motor neurons in the motor cortex, brainstem, and spinal cord. The incidence of sporadic ALS is 1.5 to 2.7 in 100,000, and the prevalence is 5.2 to 6.0 in 100,000. Conjugal ALS is even rarer than sporadic ALS. We report a case of conjugal ALS encountered in our outpatient neurology clinic. PMID:22275781

  17. Multiscale structures in relativistic pair plasmas

    SciTech Connect

    Iqbal, M.; Berezhiani, V. I.; Yoshida, Z.

    2008-03-15

    The steady-state solution of a pair plasma with relativistic thermal velocity of the constituent particles (electrons and positrons) is investigated. The relaxed state can be written as a superposition of three Beltrami fields. Generally, the associated scale parameters could be a complex conjugate pair and a real one. It is shown that at higher thermal energies, all the scale parameters become real. It is also observed that one component gets a large scale (system size) while the other two components appear with small scale of the order of the skin depth at relativistic temperature.

  18. Photoinduced electron transfer in binary blends of conjugated polymers

    SciTech Connect

    Jenekhe, A.A.; Paor, L.R. de; Chen, X.L.; Tarkka, R.M.

    1996-10-01

    The authors report observations concerning the intermolecular photoinduced electron transfer through blends of n-type/p-type {pi}-conjugated organic polymers. The results of transient absorption spectroscopy, fluorescence quenching analysis, and delocalized radical ion pair generation studies imply that these materials are supramolecular materials.

  19. Fracture Management

    MedlinePlus

    ... to hold the fracture in the correct position. • Fiberglass casting is lighter and stronger and the exterior ... with your physician if this occurs. • When a fiberglass cast is used in conjunction with a GORE- ...

  20. Stabilized polyacrylic saccharide protein conjugates

    DOEpatents

    Callstrom, M.R.; Bednarski, M.D.; Gruber, P.R.

    1996-02-20

    This invention is directed to water soluble protein polymer conjugates which are stable in hostile environments. The conjugate comprises a protein which is linked to an acrylic polymer at multiple points through saccharide linker groups. 16 figs.

  1. Stabilized polyacrylic saccharide protein conjugates

    DOEpatents

    Callstrom, Matthew R.; Bednarski, Mark D.; Gruber, Patrick R.

    1996-01-01

    This invention is directed to water soluble protein polymer conjugates which are stabile in hostile environments. The conjugate comprises a protein which is linked to an acrylic polymer at multiple points through saccharide linker groups.

  2. Conjugation in "Escherichia coli"

    ERIC Educational Resources Information Center

    Phornphisutthimas, Somkiat; Thamchaipenet, Arinthip; Panijpan, Bhinyo

    2007-01-01

    Bacterial conjugation is a genetic transfer that involves cell-to-cell between donor and recipient cells. With the current method used to teach students in genetic courses at the undergraduate level, the transconjugants are identified using bacterial physiology and/or antibiotic resistance. Using physiology, however, is difficult for both…

  3. Soviet phase conjugation research

    SciTech Connect

    Fisher, R.A.; Boyd, R.W.; Klein, M.B.; Kurnit, N.A.; Milonni, P.W.; Rockwell, D.A.; Yeh, P.

    1990-09-01

    Optical phase conjugation is a Soviet-discovered technique that applies nonlinear optical effects to automatically manipulate laser beams while automatically correcting for arbitrary distortions. Optical phase conjugation can aid in providing improved configurations for average-power and high-peak-power laser systems; it can provide nearly automatic pointing and tracking laser systems; and it can provide many other practical applications (both military and nonmilitary). Here it is important to note that 100- to 1000-watt systems are also of significant importance, not just ultra-high-energy or high-power lasers designed to do significant structural damage at significant distances. One class of phase conjugation techniques, namely, stimulated Brillouin scattering, along with its four-wave mixing counterpart, Brillioun-enhanced four-wave mixing, has been the hallmark of the Soviet effort -- with nearly all contributions (both theoretical and experimental) arising from the Soviet Union. Both stimulated Brillouin scattering and Brillouin-enhanced four-wave mixing arise from the same electrostrictive nonlinearity, where the presence of a gradient in the optical intensity produces a force on the fluid. Scientists in the United States started studying optical phase conjugation approximately five years after Soviet scientists, and initially concentrated on areas quite different from those of Soviet emphasis.

  4. DNA-cell conjugates

    DOEpatents

    Hsiao, Shih-Chia; Francis, Matthew B.; Bertozzi, Carolyn; Mathies, Richard; Chandra, Ravi; Douglas, Erik; Twite, Amy; Toriello, Nicholas; Onoe, Hiroaki

    2016-05-03

    The present invention provides conjugates of DNA and cells by linking the DNA to a native functional group on the cell surface. The cells can be without cell walls or can have cell walls. The modified cells can be linked to a substrate surface and used in assay or bioreactors.

  5. Fracture characterization of greater Ekofisk area chalks from core analysis

    SciTech Connect

    Farrell, H.E.

    1988-01-01

    Fracture characteristics are one of the input parameters for both waterflood design and subsidence analysis of the Ekofisk field. The fracture parameters of Maastrichtian age (Tor Formation) and Danian age (Ekofisk Formation) reservoir chalks have been determined from detailed description and analysis of 18 cores. Fracture pattern, mineralization, orientation, and intensity were all logged for the major groups of natural fractures. The fracture characteristics vary with chalf sedimentology. As a result, the fracturing in the Tor and Ekofisk Formation reservoirs shows some fundamental differences. The Tor Formation contains two fracture types. One set, stylolite-associated fractures, form an anastomosing network of nearly vertical extension fractures that extend between 5 and 20 cm from individual stylolites. These fractures occur predominantly in thin debris-flow facies chalks that are typical of the Tor Formation. Pilot waterflood results indicate that this fracture set imparts a permeability anisotropy to the Tor Formation reservoir in the pilot waterflood area. The second fracture set effects both Tor and Ekofisk Formation rocks. These tectonic fractures are conjugate, through-going, and planar, and they dip between 60/sup 0/ and 70/sup 0/. This group of fractures occurs predominantly in massive debris-flow facies chalks that are common in, but not restricted to, the Ekofisk Formation. Fracture orientation data indicate that a radial pattern of tectonic fractures may be present in this field. The field waterflood is being designed to accommodate this highly varied fracture pattern and analyses are under way to determine the possibility of fracture slip and closure during subsidence.

  6. Successive episodes of normal faulting and fracturing resulting from progressive extension during the uplift of the Holy Cross Mountains, Poland

    NASA Astrophysics Data System (ADS)

    Konon, Andrzej

    2004-03-01

    Conjugate normal faults, extension fractures and mesh-fracture structures were investigated in Devonian carbonate rocks from the southern part of the Holy Cross Mountains (HCM) (Central Poland). Strata folded during Variscan deformations were later subject to uplift, resulting in increasing extension in the upper part of the rock mass. At a relatively shallow depth, faults and fractures developed in an orderly vertical succession. First, mesh fracture structures and conjugate normal fault sets enclosing acute dihedral angles (2Θ) of over 45° were formed. Next, conjugate normal faults with 2Θ less than 45° and sub-vertical extension fractures developed. The occurrences of conjugate normal sets enclosing different dihedral acute angles and extension fractures with similar strikes, juxtaposed with each other at the same stratigraphic level, point to the fact that the uplifted rock mass underwent successive changes in a stress regime leading to the formation of these structures. The first sets of conjugate normal faults and fractures developed when the HCM were uplifted during a late stage of Variscan deformations. The next sets of extension fractures and conjugate normal faults developed during the following uplift events interrupted by periods of sedimentation of the Mesozoic and younger strata.

  7. Hydraulic fracturing-1

    SciTech Connect

    Not Available

    1990-01-01

    This book contains papers on hydraulic fracturing. Topics covered include: An overview of recent advances in hydraulic fracturing technology; Containment of massive hydraulic fracture; and Fracturing with a high-strength proppant.

  8. Pediatric Thighbone (Femur) Fracture

    MedlinePlus

    ... fractures in infants under 1 year old is child abuse. Child abuse is also a leading cause of thighbone fracture ... contact sports • Being in a motor vehicle accident • Child abuse Types of Femur Fractures (Classification) Femur fractures vary ...

  9. Conjugate flow action functionals

    SciTech Connect

    Venturi, Daniele

    2013-11-15

    We present a new general framework to construct an action functional for a non-potential field theory. The key idea relies on representing the governing equations relative to a diffeomorphic flow of curvilinear coordinates which is assumed to be functionally dependent on the solution field. Such flow, which will be called the conjugate flow, evolves in space and time similarly to a physical fluid flow of classical mechanics and it can be selected in order to symmetrize the Gâteaux derivative of the field equations with respect to suitable local bilinear forms. This is equivalent to requiring that the governing equations of the field theory can be derived from a principle of stationary action on a Lie group manifold. By using a general operator framework, we obtain the determining equations of such manifold and the corresponding conjugate flow action functional. In particular, we study scalar and vector field theories governed by second-order nonlinear partial differential equations. The identification of transformation groups leaving the conjugate flow action functional invariant could lead to the discovery of new conservation laws in fluid dynamics and other disciplines.

  10. Conjugate flow action functionals

    NASA Astrophysics Data System (ADS)

    Venturi, Daniele

    2013-11-01

    We present a new general framework to construct an action functional for a non-potential field theory. The key idea relies on representing the governing equations relative to a diffeomorphic flow of curvilinear coordinates which is assumed to be functionally dependent on the solution field. Such flow, which will be called the conjugate flow, evolves in space and time similarly to a physical fluid flow of classical mechanics and it can be selected in order to symmetrize the Gâteaux derivative of the field equations with respect to suitable local bilinear forms. This is equivalent to requiring that the governing equations of the field theory can be derived from a principle of stationary action on a Lie group manifold. By using a general operator framework, we obtain the determining equations of such manifold and the corresponding conjugate flow action functional. In particular, we study scalar and vector field theories governed by second-order nonlinear partial differential equations. The identification of transformation groups leaving the conjugate flow action functional invariant could lead to the discovery of new conservation laws in fluid dynamics and other disciplines.

  11. Mechanisms for shrinkage fracturing at Meridiani Planum

    NASA Astrophysics Data System (ADS)

    Watters, W. A.; Squyres, S. W.

    2009-12-01

    We investigate the role of water in fracturing at Meridiani Planum with the aim of shedding light on the history of densely-fractured outcroppings of light-toned rocks at low-latitudes on Mars. The fractures that occur throughout the inter-crater plains at Meridiani exhibit many characteristics of shrinkage cracks: they have significant width (i.e., not hairline), commonly connect in 90-degree and 120-degree junctions, and exhibit a "hierarchical" organization: i.e., the longest fractures are widest, and narrower fractures terminate against wider fractures at 90-degree junctions (T-shaped). Using the Pancam and Navcam stereo-pair images acquired by the Opportunity rover, we have measured the geometric scaling of fracture networks at Meridiani (e.g., fracture width vs. fracture separation) as well as the total volume change. We have also characterized the diversity of patterns in detail, as well as the modification of fractures and polygonal "tiles" by wind-blown sand abrasion. Identical observations were carried-out for an analogue site where similar fractures are ubiquitous in the playas of Death Valley, California, and where modification processes are also comparable. By also estimating the expected volume change and results from numerical models of shrinkage fracturing, we evaluate the likelihood of three candidate contraction mechanisms: loss of water bound in hydrated minerals (dehydration), loss of water from pore spaces (desiccation), and contraction from cooling (thermal fracturing). The evidence to date favors the second of these (desiccation); this result would have significant implications for the history of Meridiani since the time when sulfate-rich sediments were deposited.

  12. Physical matching of metals: grain orientation association at fracture edge.

    PubMed

    Lograsso, Barbara K

    2015-01-01

    The objective of this study was to examine whether surface crystal orientation can be used to associate or differentiate metal fracture fragments. The orientations of individual crystals and crystals across the fracture plane were measured on polished steel and iron alloy surfaces using Electron Backscattered Diffraction/ Orientation Imaging Microscopy (EBSD/OIM). This investigation examined crystallographic characteristics within a metal. This study showed that for transgranular fracture, it is feasible that pieces of grains could be associated across the fracture surface with the difference in orientation between grains (misorientation) along a length sequence of grain orientations on one side of the fracture surface to associate the other side of a fracture surface. Regarding pair comparisons of crystals on fracture surfaces, it was estimated that the probability for an ordered sequence of six distinct oriented grains along a fracture surface to occur again is about 1 in 4.82 (10)(30) or 2.07 (10)(-31). PMID:25619870

  13. Molecular and biochemical analysis of conjugation and adolescence in Tetrahymena thermophila

    SciTech Connect

    Rogers, M.B.

    1986-01-01

    A previously unrecognized stage in the development of sexual maturity in Tetrahymena thermophila, adolescence, has been described. When the progeny of successfully mated cells are grown logarithmically, they are unable to form mating pairs for about 65 generations. This period is known as immaturity. During the next stage, adolescence, the progeny pair with mature cells but not with other adolescent cells despite the presence of complementary mating types. Adolescence persists for 20-25 generations before the cells attain maturity (the ability to mate with any cell of different mating type). Once paired with mature cells, adolescents successfully complete conjugation was shown genetically. Mating pairs formed between adolescent and mature cells are indistinguishable from those formed between mature cells by the criteria of cytology and two-dimensional gel electrophoresis of proteins extracted from mating pairs pulse-labelled with (/sup 35/S)methionine. An analysis of proteins induced during the first ten hours of conjugation was carried out using two-dimensional gel electrophoresis. The protein patterns obtained from all controls were similar. The synthesis of numerous large and basic proteins were induced during conjugation. The majority of the proteins were detected during meiosis and none were mating type specific. A library of micronuclear DNA was constructed in the plasmic PUC18. The library was screened by differential colony hybridization using cDNA complementary to polyA/sup +/ RNA isolated from conjugating and control cells. Eight recombinant clones were isolated which contain sequences transcriptionally induced in conjugating cells.

  14. Conjugate and method for forming aminomethyl phosphorus conjugates

    DOEpatents

    Katti, Kattesh V.; Berning, Douglas E.; Volkert, Wynn A.; Ketring, Alan R.; Churchill, Robert

    1999-01-01

    A method of forming phosphine-amine conjugates includes reacting a hydroxymethyl phosphine group of an amine-free first molecule with at least one free amine group of a second molecule to covalently bond the first molecule with the second molecule through an aminomethyl phosphorus linkage and the conjugates formed thereby.

  15. Pairing forces in nuclei

    SciTech Connect

    Chasman, R.R.

    1996-12-31

    In this contribution, the author mentions some features of pairing forces that are unique to nuclei and cover some areas of major interest in nuclear structure research, that involve pairing. At the level of most nuclear structure studies, nuclei are treated as consisting of two kinds of fermions (protons and neutrons) in a valence space with rather few levels. These features give rise to unique aspects of pairing forces in nuclei: (1) n-p pairing in T = 0 as well as the usual T = 1 pairing that is characteristic of like fermions; (2) a need to correct pairing calculations for the (1/N) effects that can typically be neglected in superconducting solids. An issue of current concern is the nature of the pairing interaction: several recent studies suggest a need for a density dependent form of the pairing interaction. There is a good deal of feedback between the questions of accurate calculations of pairing interactions and the form and magnitude of the pairing interaction. Finally, the authors discuss some many-body wave functions that are a generalization of the BCS wave function form, and apply them to a calculation of energy level spacings in superdeformed rotational bands.

  16. Matched-pair classification

    SciTech Connect

    Theiler, James P

    2009-01-01

    Following an analogous distinction in statistical hypothesis testing, we investigate variants of machine learning where the training set comes in matched pairs. We demonstrate that even conventional classifiers can exhibit improved performance when the input data has a matched-pair structure. Online algorithms, in particular, converge quicker when the data is presented in pairs. In some scenarios (such as the weak signal detection problem), matched pairs can be generated from independent samples, with the effect not only doubling the nominal size of the training set, but of providing the structure that leads to better learning. A family of 'dipole' algorithms is introduced that explicitly takes advantage of matched-pair structure in the input data and leads to further performance gains. Finally, we illustrate the application of matched-pair learning to chemical plume detection in hyperspectral imagery.

  17. Another hybrid conjugate gradient algorithm for unconstrained optimization

    NASA Astrophysics Data System (ADS)

    Andrei, Neculai

    2008-02-01

    Another hybrid conjugate gradient algorithm is subject to analysis. The parameter ? k is computed as a convex combination of beta ^{{HS}}_{k} (Hestenes-Stiefel) and beta ^{{DY}}_{k} (Dai-Yuan) algorithms, i.eE beta ^{C}_{k} = {left( {1 - theta _{k} } right)}beta ^{{HS}}_{k} + theta _{k} beta ^{{DY}}_{k} . The parameter ? k in the convex combination is computed in such a way so that the direction corresponding to the conjugate gradient algorithm to be the Newton direction and the pair (s k , y k ) to satisfy the quasi-Newton equation nabla ^{2} f{left( {x_{{k + 1}} } right)}s_{k} = y_{k} , where s_{k} = x_{{k + 1}} - x_{k} and y_{k} = g_{{k + 1}} - g_{k} . The algorithm uses the standard Wolfe line search conditions. Numerical comparisons with conjugate gradient algorithms show that this hybrid computational scheme outperforms the Hestenes-Stiefel and the Dai-Yuan conjugate gradient algorithms as well as the hybrid conjugate gradient algorithms of Dai and Yuan. A set of 750 unconstrained optimization problems are used, some of them from the CUTE library.

  18. Antibody-gold cluster conjugates

    DOEpatents

    Hainfeld, J.F.

    1988-06-28

    Antibody- or antibody fragment-gold cluster conjugates are shown wherein the conjugate size can be about 5.0 nm. Methods and reagents are disclosed in which antibodies or Fab' fragments thereof are covalently bound to a stable cluster of gold atoms. 2 figs.

  19. Vortex pairs on surfaces

    SciTech Connect

    Koiller, Jair

    2009-05-06

    A pair of infinitesimally close opposite vortices moving on a curved surface moves along a geodesic, according to a conjecture by Kimura. We outline a proof. Numerical simulations are presented for a pair of opposite vortices at a close but nonzero distance on a surface of revolution, the catenoid. We conjecture that the vortex pair system on a triaxial ellipsoid is a KAM perturbation of Jacobi's geodesic problem. We outline some preliminary calculations required for this study. Finding the surfaces for which the vortex pair system is integrable is in order.

  20. An integrated approach for enhanced protein conjugation and capture with viral nanotemplates and hydrogel microparticle platforms via rapid bioorthogonal reactions.

    PubMed

    Jung, Sukwon; Yi, Hyunmin

    2014-07-01

    We demonstrate significantly enhanced protein conjugation and target protein capture capacity by exploiting tobacco mosaic virus (TMV) templates assembled with hydrogel microparticles. Protein conjugation results with a red fluorescent protein R-Phycoerythrin (R-PE) show significantly enhanced protein conjugation capacity of TMV-assembled particles (TMV-particles) compared to planar substrates or hydrogel microparticles. In-depth examination of protein conjugation kinetics via tetrazine (Tz)-trans-cyclooctene (TCO) cycloaddition and strain-promoted alkyne-azide cycloaddition (SPAAC) reaction demonstrates that TMV-particles provide a less hindered environment for protein conjugation. Target protein capture results using an anti-R-PE antibody (R-Ab)-R-PE pair also show substantially improved capture capacity of R-Ab conjugated TMV-particles over R-Ab conjugated hydrogel microparticles. We further demonstrate readily controlled protein and antibody conjugation capacity by simply varying TMV concentrations, which show negligible negative impact of densely assembled TMVs on protein conjugation and capture capacity. Combined, these results illustrate a facile postfabrication protein conjugation approach with TMV templates assembled onto hydrogel microparticles for improved and controlled protein conjugation and sensing platforms. We anticipate that our approach can be readily applied to various protein sensing applications. PMID:24937661

  1. Non Linear Conjugate Gradient

    Energy Science and Technology Software Center (ESTSC)

    2006-11-17

    Software that simulates and inverts electromagnetic field data for subsurface electrical properties (electrical conductivity) of geological media. The software treats data produced by a time harmonic source field excitation arising from the following antenna geometery: loops and grounded bipoles, as well as point electric and magnetic dioples. The inversion process is carried out using a non-linear conjugate gradient optimization scheme, which minimizes the misfit between field data and model data using a least squares criteria.more » The software is an upgrade from the code NLCGCS_MP ver 1.0. The upgrade includes the following components: Incorporation of new 1 D field sourcing routines to more accurately simulate the 3D electromagnetic field for arbitrary geologic& media, treatment for generalized finite length transmitting antenna geometry (antennas with vertical and horizontal component directions). In addition, the software has been upgraded to treat transverse anisotropy in electrical conductivity.« less

  2. Generalized conjugate gradient squared

    SciTech Connect

    Fokkema, D.R.; Sleijpen, G.L.G.

    1994-12-31

    In order to solve non-symmetric linear systems of equations, the Conjugate Gradient Squared (CGS) is a well-known and widely used iterative method. In practice the method converges fast, often twice as fast as the Bi-Conjugate Gradient method. This is what you may expect, since CGS uses the square of the BiCG polynomial. However, CGS may suffer from its erratic convergence behavior. The method may diverge or the approximate solution may be inaccurate. BiCGSTAB uses the BiCG polynomial and a product of linear factors in an attempt to smoothen the convergence. In many cases, this has proven to be very effective. Unfortunately, the convergence of BiCGSTAB may stall when a linear factor (nearly) degenerates. BiCGstab({ell}) is designed to overcome this degeneration of linear factors. It generalizes BiCGSTAB and uses both the BiCG polynomial and a product of higher order factors. Still, CGS may converge faster than BiCGSTAB or BiCGstab({ell}). So instead of using a product of linear or higher order factors, it may be worthwhile to look for other polynomials. Since the BiCG polynomial is based on a three term recursion, a natural choice would be a polynomial based on another three term recursion. Possibly, a suitable choice of recursion coefficients would result in method that converges faster or as fast as CGS, but less erratic. It turns out that an algorithm for such a method can easily be formulated. One particular choice for the recursion coefficients leads to CGS. Therefore one could call this algorithm generalized CGS. Another choice for the recursion coefficients leads to BiCGSTAB. It is therefore possible to mix linear factors and some polynomial based on a three term recursion. This way one may get the best of both worlds. The authors will report on their findings.

  3. Radial head fracture - aftercare

    MedlinePlus

    Elbow fracture - radial head - aftercare ... the radius bone, just below your elbow. A fracture is a break in your bone. The most common cause of a radial head fracture is falling with an outstretched arm.

  4. Hand fracture - aftercare

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000552.htm Hand fracture - aftercare To use the sharing features on ... need to be repaired with surgery. Types of hand fractures Your fracture may be in one of ...

  5. Critical Schwinger Pair Production

    NASA Astrophysics Data System (ADS)

    Gies, Holger; Torgrimsson, Greger

    2016-03-01

    We investigate Schwinger pair production in spatially inhomogeneous electric backgrounds. A critical point for the onset of pair production can be approached by fields that marginally provide sufficient electrostatic energy for an off-shell long-range electron-positron fluctuation to become a real pair. Close to this critical point, we observe features of universality which are analogous to continuous phase transitions in critical phenomena with the pair-production rate serving as an order parameter: electric backgrounds can be subdivided into universality classes and the onset of pair production exhibits characteristic scaling laws. An appropriate design of the electric background field can interpolate between power-law scaling, essential Berezinskii-Kosterlitz-Thouless-type scaling, and a power-law scaling with log corrections. The corresponding critical exponents only depend on the large-scale features of the electric background, whereas the microscopic details of the background play the role of irrelevant perturbations not affecting criticality.

  6. Critical Schwinger Pair Production.

    PubMed

    Gies, Holger; Torgrimsson, Greger

    2016-03-01

    We investigate Schwinger pair production in spatially inhomogeneous electric backgrounds. A critical point for the onset of pair production can be approached by fields that marginally provide sufficient electrostatic energy for an off-shell long-range electron-positron fluctuation to become a real pair. Close to this critical point, we observe features of universality which are analogous to continuous phase transitions in critical phenomena with the pair-production rate serving as an order parameter: electric backgrounds can be subdivided into universality classes and the onset of pair production exhibits characteristic scaling laws. An appropriate design of the electric background field can interpolate between power-law scaling, essential Berezinskii-Kosterlitz-Thouless-type scaling, and a power-law scaling with log corrections. The corresponding critical exponents only depend on the large-scale features of the electric background, whereas the microscopic details of the background play the role of irrelevant perturbations not affecting criticality. PMID:26991162

  7. Cooper Pairs in Insulators?!

    ScienceCinema

    James Valles

    2010-01-08

    Nearly 50 years elapsed between the discovery of superconductivity and the emergence of the microscopic theory describing this zero resistance state. The explanation required a novel phase of matter in which conduction electrons joined in weakly bound pairs and condensed with other pairs into a single quantum state. Surprisingly, this Cooper pair formation has also been invoked to account for recently uncovered high-resistance or insulating phases of matter. To address this possibility, we have used nanotechnology to create an insulating system that we can probe directly for Cooper pairs. I will present the evidence that Cooper pairs exist and dominate the electrical transport in these insulators and I will discuss how these findings provide new insight into superconductor to insulator quantum phase transitions. 

  8. Pair contact process with diffusion of pairs

    NASA Astrophysics Data System (ADS)

    Santos, F. L.; Dickman, Ronald; Fulco, U. L.

    2011-03-01

    The pair contact process (PCP) is a nonequilibrium stochastic model which, like the basic contact process (CP), exhibits a phase transition to an absorbing state. The two models belong to the directed percolation (DP) universality class, despite the fact that the PCP possesses infinitely many absorbing configurations whereas the CP has but one. The critical behavior of the PCP with hopping by particles (PCPD) is as yet unclear. Here we study a version of the PCP in which nearest-neighbor particle pairs can hop but individual particles cannot. Using quasistationary simulations for three values of the diffusion probability (D = 0.1, 0.5 and 0.9), we find convincing evidence of DP-like critical behavior.

  9. Conjugating binary systems for spacecraft thermal control

    NASA Technical Reports Server (NTRS)

    Grodzka, Philomena G.; Dean, William G.; Sisk, Lori A.; Karu, Zain S.

    1989-01-01

    The materials search was directed to liquid pairs which can form hydrogen bonds of just the right strength, i.e., strong enough to give a high heat of mixing, but weak enough to enable phase change to occur. The cursory studies performed in the area of additive effects indicate that Conjugating Binary (CB) performance can probably be fine-tuned by this means. The Fluid Loop Test Systems (FLTS) tests of candidate CBs indicate that the systems Triethylamine (TEA)/water and propionaldehyde/water show close to the ideal, reversible behavior, at least initially. The Quick Screening Tests QSTs and FLTS tests, however, both suffer from rather severe static due either to inadequate stirring or temperature control. Thus it is not possible to adequately evaluate less than ideal CB performers. Less than ideal performers, it should be noted, may have features that make them better practical CBs than ideal performers. Improvement of the evaluation instrumentation is thus indicated.

  10. Fractured Surface

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Context image for PIA03084 Fractured Surface

    These fractures and graben are part of Gordii Fossae, a large region that has undergone stresses which have cracked the surface.

    Image information: VIS instrument. Latitude 16.6S, Longitude 234.3E. 18 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  11. Adjacent Lone Pair (ALP) Effect: A Computational Approach for Its Origin.

    PubMed

    Zhang, Huaiyu; Wu, Wei; Ahmed, Basil M; Mezei, Gellert; Mo, Yirong

    2016-05-23

    The adjacent lone pair (ALP) effect is an experimental phenomenon in certain nitrogenous heterocyclic systems exhibiting the preference of the products with lone pairs separated over other isomers with lone pairs adjacent. A theoretical elucidation of the ALP effect requires the decomposition of intramolecular energy terms and the isolation of lone pair-lone pair interactions. Here we used the block-localized wavefunction (BLW) method within the ab initio valence bond (VB) theory to derive the strictly localized orbitals which are used to accommodate one-atom centered lone pairs and two-atom centered σ or π bonds. As such, interactions among electron pairs can be directly derived. Two-electron integrals between adjacent lone pairs do not support the view that the lone pair-lone pair repulsion is responsible for the ALP effect. Instead, the disabling of π conjugation greatly diminishes the ALP effect, indicating that the reduction of π conjugation in deprotonated forms with two σ lone pairs adjacent is one of the major causes for the ALP effect. Further electrostatic potential analysis and intramolecular energy decomposition confirm that the other key factor is the favorable electrostatic attraction within the isomers with lone pairs separated. PMID:27139318

  12. Targeting cancer using cholesterol conjugates

    PubMed Central

    Radwan, Awwad A.; Alanazi, Fares K.

    2013-01-01

    Conjugation of cholesterol moiety to active compounds for either cancer treatment or diagnosis is an attractive approach. Cholesterol derivatives are widely studied as cancer diagnostic agents and as anticancer derivatives either in vitro or in vivo using animal models. In largely growing studies, anticancer agents have been chemically conjugated to cholesterol molecules, to enhance their pharmacokinetic behavior, cellular uptake, target specificity, and safety. To efficiently deliver anticancer agents to the target cells and tissues, many different cholesterol–anticancer conjugates were synthesized and characterized, and their anticancer efficiencies were tested in vitro and in vivo. PMID:24493968

  13. The Differences in Onset Time of Conjugate Substorms

    NASA Astrophysics Data System (ADS)

    Weygand, J. M.; Zesta, E.; McPherron, R. L.; Hsu, T. S.

    2014-12-01

    The auroral electrojet (AE) index is traditionally calculated from 13 ground magnetometer stations located around the typical northern auroral oval location. Similar coverage in the Southern Hemisphere index (SAE) does not exist, so the AE calculation has only been performed using Northern Hemisphere data. In the present study, we use seven southern auroral region ground magnetometers as well as their conjugate Northern Hemisphere data to calculate conjugate AE indices for 274 days covering all four seasons. With this dataset over 1200 substorm onsets have been identified in the SAE index using the technique of Hsu et al. [2012]. A comparison of the SAE index with the world data center standard AE index shows that the substorm onsets do not always occur at the same time with differences on the order of several minutes. In this study we examine the differences in the onset time and the reason for those differences using our conjugate AE indices and using pairs of conjugate ground magnetometer stations. Specifically, we used the pair of stations at West Antarctica Ice Sheet Divide and Sanikiluaq, Canada and Syowa, Antarctica and Tjörnes, Iceland. The largest differences in onset time appear to be related to the IMF Bz and magnetic field line length. Differences on the order of minutes for the onset time of conjugate substorms have serious implications for substorm theories. The problem is that waves from a current disruption region to the mid tail, or flows from the mid tail to the current disruption region take the same amount of time (~2 minutes), which makes it difficult to decide where the onset disturbance is initiated, particularly when onset indicators have differences on the order of minutes.

  14. Electron pairing without superconductivity.

    PubMed

    Cheng, Guanglei; Tomczyk, Michelle; Lu, Shicheng; Veazey, Joshua P; Huang, Mengchen; Irvin, Patrick; Ryu, Sangwoo; Lee, Hyungwoo; Eom, Chang-Beom; Hellberg, C Stephen; Levy, Jeremy

    2015-05-14

    Strontium titanate (SrTiO3) is the first and best known superconducting semiconductor. It exhibits an extremely low carrier density threshold for superconductivity, and possesses a phase diagram similar to that of high-temperature superconductors--two factors that suggest an unconventional pairing mechanism. Despite sustained interest for 50 years, direct experimental insight into the nature of electron pairing in SrTiO3 has remained elusive. Here we perform transport experiments with nanowire-based single-electron transistors at the interface between SrTiO3 and a thin layer of lanthanum aluminate, LaAlO3. Electrostatic gating reveals a series of two-electron conductance resonances-paired electron states--that bifurcate above a critical pairing field Bp of about 1-4 tesla, an order of magnitude larger than the superconducting critical magnetic field. For magnetic fields below Bp, these resonances are insensitive to the applied magnetic field; for fields in excess of Bp, the resonances exhibit a linear Zeeman-like energy splitting. Electron pairing is stable at temperatures as high as 900 millikelvin, well above the superconducting transition temperature (about 300 millikelvin). These experiments demonstrate the existence of a robust electronic phase in which electrons pair without forming a superconducting state. Key experimental signatures are captured by a model involving an attractive Hubbard interaction that describes real-space electron pairing as a precursor to superconductivity. PMID:25971511

  15. Electron pairing without superconductivity

    NASA Astrophysics Data System (ADS)

    Cheng, Guanglei; Tomczyk, Michelle; Lu, Shicheng; Veazey, Joshua P.; Huang, Mengchen; Irvin, Patrick; Ryu, Sangwoo; Lee, Hyungwoo; Eom, Chang-Beom; Hellberg, C. Stephen; Levy, Jeremy

    2015-05-01

    Strontium titanate (SrTiO3) is the first and best known superconducting semiconductor. It exhibits an extremely low carrier density threshold for superconductivity, and possesses a phase diagram similar to that of high-temperature superconductors--two factors that suggest an unconventional pairing mechanism. Despite sustained interest for 50 years, direct experimental insight into the nature of electron pairing in SrTiO3 has remained elusive. Here we perform transport experiments with nanowire-based single-electron transistors at the interface between SrTiO3 and a thin layer of lanthanum aluminate, LaAlO3. Electrostatic gating reveals a series of two-electron conductance resonances--paired electron states--that bifurcate above a critical pairing field Bp of about 1-4 tesla, an order of magnitude larger than the superconducting critical magnetic field. For magnetic fields below Bp, these resonances are insensitive to the applied magnetic field; for fields in excess of Bp, the resonances exhibit a linear Zeeman-like energy splitting. Electron pairing is stable at temperatures as high as 900 millikelvin, well above the superconducting transition temperature (about 300 millikelvin). These experiments demonstrate the existence of a robust electronic phase in which electrons pair without forming a superconducting state. Key experimental signatures are captured by a model involving an attractive Hubbard interaction that describes real-space electron pairing as a precursor to superconductivity.

  16. Electron pairing without superconductivity

    NASA Astrophysics Data System (ADS)

    Levy, Jeremy

    Strontium titanate (SrTiO3) is the first and best known superconducting semiconductor. It exhibits an extremely low carrier density threshold for superconductivity, and possesses a phase diagram similar to that of high-temperature superconductors--two factors that suggest an unconventional pairing mechanism. Despite sustained interest for 50 years, direct experimental insight into the nature of electron pairing in SrTiO3 has remained elusive. Here we perform transport experiments with nanowire-based single-electron transistors at the interface between SrTiO3 and a thin layer of lanthanum aluminate, LaAlO3. Electrostatic gating reveals a series of two-electron conductance resonances--paired electron states--that bifurcate above a critical pairing field Bp of about 1-4 tesla, an order of magnitude larger than the superconducting critical magnetic field. For magnetic fields below Bp, these resonances are insensitive to the applied magnetic field; for fields in excess of Bp, the resonances exhibit a linear Zeeman-like energy splitting. Electron pairing is stable at temperatures as high as 900 millikelvin, well above the superconducting transition temperature (about 300 millikelvin). These experiments demonstrate the existence of a robust electronic phase in which electrons pair without forming a superconducting state. Key experimental signatures are captured by a model involving an attractive Hubbard interaction that describes real-space electron pairing as a precursor to superconductivity. Support from AFOSR, ONR, ARO, NSF, DOE and NSSEFF is gratefully acknowledged.

  17. Paired Straight Hearth Furnace

    SciTech Connect

    2009-04-01

    This factsheet describes a research project whose goals are to design, develop, and evaluate the scalability and commercial feasibility of the PSH Paired Straight Hearth Furnace alternative ironmaking process.

  18. Defined DNA/nanoparticle conjugates.

    PubMed

    Ackerson, Christopher J; Sykes, Michael T; Kornberg, Roger D

    2005-09-20

    Glutathione monolayer-protected gold clusters were reacted by place exchange with 19- or 20-residue thiolated oligonucleotides. The resulting DNA/nanoparticle conjugates could be separated on the basis of the number of bound oligonucleotides by gel electrophoresis and assembled with one another by DNA-DNA hybridization. This approach overcomes previous limitations of DNA/nanoparticle synthesis and yields conjugates that are precisely defined with respect to both gold and nucleic acid content. PMID:16155122

  19. Microseismic Velocity Imaging of the Fracturing Zone

    NASA Astrophysics Data System (ADS)

    Zhang, H.; Chen, Y.

    2015-12-01

    Hydraulic fracturing of low permeability reservoirs can induce microseismic events during fracture development. For this reason, microseismic monitoring using sensors on surface or in borehole have been widely used to delineate fracture spatial distribution and to understand fracturing mechanisms. It is often the case that the stimulated reservoir volume (SRV) is determined solely based on microseismic locations. However, it is known that for some fracture development stage, long period long duration events, instead of microseismic events may be associated. In addition, because microseismic events are essentially weak and there exist different sources of noise during monitoring, some microseismic events could not be detected and thus located. Therefore the estimation of the SRV is biased if it is solely determined by microseismic locations. With the existence of fluids and fractures, the seismic velocity of reservoir layers will be decreased. Based on this fact, we have developed a near real time seismic velocity tomography method to characterize velocity changes associated with fracturing process. The method is based on double-difference seismic tomography algorithm to image the fracturing zone where microseismic events occur by using differential arrival times from microseismic event pairs. To take into account varying data distribution for different fracking stages, the method solves the velocity model in the wavelet domain so that different scales of model features can be obtained according to different data distribution. We have applied this real time tomography method to both acoustic emission data from lab experiment and microseismic data from a downhole microseismic monitoring project for shale gas hydraulic fracturing treatment. The tomography results from lab data clearly show the velocity changes associated with different rock fracturing stages. For the field data application, it shows that microseismic events are located in low velocity anomalies. By

  20. Cooper Pair Insulators

    NASA Astrophysics Data System (ADS)

    Valles, James

    One of the recent advances in the field of the Superconductor to Insulator Transition (SIT) has been the discovery and characterization of the Cooper Pair Insulator phase. This bosonic insulator, which consists of localized Cooper pairs, exhibits activated transport and a giant magneto-resistance peak. These features differ markedly from the weakly localized transport that emerges as pairs break at a ``fermionic'' SIT. I will describe how our experiments on films nano-patterned with a nearly triangular array of holes have enabled us to 1) distinguish bosonic insulators from fermionic insulators, 2) show that Cooper pairs, rather than quasi-particles dominate the transport in the Cooper Pair insulator phase, 3) demonstrate that very weak, sub nano-meter thickness inhomogeneities control whether a bosonic or fermionic insulator forms at an SIT and 4) reveal that Cooper pairs disintegrate rather than becoming more tightly bound deep in the localized phase. We have also developed a method, using a magnetic field, to tune flux disorder reversibly in these films. I will present our latest results on the influence of magnetic flux disorder and random gauge fields on phenomena near bosonic SITs. This work was performed in collaboration with M. D. Stewart, Jr., Hung Q. Nguyen, Shawna M. Hollen, Jimmy Joy, Xue Zhang, Gustavo Fernandez, Jeffrey Shainline and Jimmy Xu. It was supported by NSF Grants DMR 1307290 and DMR-0907357.

  1. Polymeric conjugates for drug delivery

    PubMed Central

    Larson, Nate; Ghandehari, Hamidreza

    2012-01-01

    The field of polymer therapeutics has evolved over the past decade and has resulted in the development of polymer-drug conjugates with a wide variety of architectures and chemical properties. Whereas traditional non-degradable polymeric carriers such as poly(ethylene glycol) (PEG) and N-(2-hydroxypropyl methacrylamide) (HPMA) copolymers have been translated to use in the clinic, functionalized polymer-drug conjugates are increasingly being utilized to obtain biodegradable, stimuli-sensitive, and targeted systems in an attempt to further enhance localized drug delivery and ease of elimination. In addition, the study of conjugates bearing both therapeutic and diagnostic agents has resulted in multifunctional carriers with the potential to both “see and treat” patients. In this paper, the rational design of polymer-drug conjugates will be discussed followed by a review of different classes of conjugates currently under investigation. The design and chemistry used for the synthesis of various conjugates will be presented with additional comments on their potential applications and current developmental status. PMID:22707853

  2. Fracturing operations in a dry geothermal reservoir

    SciTech Connect

    Rowley, J.C.; Hendron, R.H.; Nicholson, R.W.; Pettitt, R.A.; Sinclair, A.R.

    1983-10-01

    Fracturing and completing deep wells in hot, non-porous crystalline basement rock challenges conventional equipment use, procedures, and techniques common in oil and gas and normal geothermal completions. Fracturing operations at the Fenton Hill, New Mexico, Hot Dry Rock (HDR) Geothermal Test Site initiated unique developments necessary to solve problems caused by an extremely harsh downhole environment. Two deep wells were drilled to approximately 15,000 ft (4.6 km); formation temperatures are in excess of 600/sup 0/F (315/sup 0/C). The wells were drilled during 1979-1981, inclined at 35 degrees, one above the other, and directionally drilled in an azimuthal direction orthogonal to the least principal in-situ crustal stress field. The pair of wells form the injection and production wells of an energy extraction system which will be unique in reservoir development. Hydraulic fracturing experiments to connect the two wells have used openhole packers, hydraulic jet notching of the borehole wall, cemented-in isolation liners and casing packers. Problems were encountered with hole drag, high fracture gradients, H/sub 2/S in vent back fluids, stress corrosion cracking of tubulars, and the complex nature of three-dimensional fracture growth that requires very large volumes of injected water. Two fractured zones have been formed by hydraulic fracturing and defined by close-in, borehole deployed, microseismic detectors.

  3. Fracture channel waves

    SciTech Connect

    Nihei, K.T.; Yi, W.; Myer, L.R.; Cook, N.G.; Schoenberg, M.

    1999-03-01

    The properties of guided waves which propagate between two parallel fractures are examined. Plane wave analysis is used to obtain a dispersion equation for the velocities of fracture channel waves. Analysis of this equation demonstrates that parallel fractures form an elastic waveguide that supports two symmetric and two antisymmetric dispersive Rayleigh channel waves, each with particle motions and velocities that are sensitive to the normal and tangential stiffnesses of the fractures. These fracture channel waves degenerate to shear waves when the fracture stiffnesses are large, to Rayleigh waves and Rayleigh-Lamb plate waves when the fracture stiffnesses are low, and to fracture interface waves when the fractures are either very closely spaced or widely separated. For intermediate fracture stiffnesses typical of fractured rock masses, fracture channel waves are dispersive and exhibit moderate to strong localization of guided wave energy between the fractures. The existence of these waves is examined using laboratory acoustic measurements on a fractured marble plate. This experiment confirms the distinct particle motion of the fundamental antisymmetric fracture channel wave (A{sub 0} mode) and demonstrates the ease with which a fracture channel wave can be generated and detected. {copyright} 1999 American Geophysical Union

  4. 3D Display Using Conjugated Multiband Bandpass Filters

    NASA Technical Reports Server (NTRS)

    Bae, Youngsam; White, Victor E.; Shcheglov, Kirill

    2012-01-01

    Stereoscopic display techniques are based on the principle of displaying two views, with a slightly different perspective, in such a way that the left eye views only by the left eye, and the right eye views only by the right eye. However, one of the major challenges in optical devices is crosstalk between the two channels. Crosstalk is due to the optical devices not completely blocking the wrong-side image, so the left eye sees a little bit of the right image and the right eye sees a little bit of the left image. This results in eyestrain and headaches. A pair of interference filters worn as an optical device can solve the problem. The device consists of a pair of multiband bandpass filters that are conjugated. The term "conjugated" describes the passband regions of one filter not overlapping with those of the other, but the regions are interdigitated. Along with the glasses, a 3D display produces colors composed of primary colors (basis for producing colors) having the spectral bands the same as the passbands of the filters. More specifically, the primary colors producing one viewpoint will be made up of the passbands of one filter, and those of the other viewpoint will be made up of the passbands of the conjugated filter. Thus, the primary colors of one filter would be seen by the eye that has the matching multiband filter. The inherent characteristic of the interference filter will allow little or no transmission of the wrong side of the stereoscopic images.

  5. What can the dihedral angle of conjugate-faults tell us?

    NASA Astrophysics Data System (ADS)

    Ismat, Zeshan

    2015-04-01

    Deformation within the upper crust (elastico-frictional regime) is largely accommodated by fractures and conjugate faults. The Coulomb fracture criterion leads us to expect that the average dihedral angle of conjugate-fault sets is expected to be ∼60°. Experiments, however, reveal a significant amount of scatter from this 60° average. The confining pressure under which these rocks are deformed is a contributing factor to this scatter. The Canyon Range syncline, Sevier fold-thrust belt (USA) and the Jebel Bani, Anti-Atlas fold-belt (Morocco) both folded under different depths, within the elastico-frictional regime, by cataclastic flow. Conjugate-fault sets assisted deformation by cataclastic flow. The Canyon Range syncline and the Jebel Bani are used here as natural examples to test the relationship between the dihedral angle of conjugate-faults and confining pressure. Variations is confining pressure are modeled by the difference in depth of deformation and position within the folds. Results from this study show that the dihedral angle increases with an increase in depth and within the hinge regions of folds, where space problems commonly occur. Moreover, the shortening directions based on the acute bisectors of conjugate-faults may not be accurately determined if the dihedral angles are unusually large or small, leading to incorrect kinematic analyses.

  6. The use of hybrid fractures in paleostress determinations: test case with the the Palygorskite-bearing fractures in the Kinshasa area, DR Congo

    NASA Astrophysics Data System (ADS)

    Delvaux, Damien; Gloire, Ganza; Mees, Florias; Lahogue, Pascale

    2014-05-01

    Hybrid fractures represent the transition from extension fracture to shear fracture (Ramsey and Chester, 2004, Nature 428, 63-66). Although hybrid fractures have long been hypothesized to represent brittle fracture types between the extension and shear fractures end-members, it was only in 2004 that these authors succeeded to demonstrate their existence experimentally. As a consequence, observation of hybrid fractures in naturally deformed rocks remained ambiguous for a long time and only few studies reported their natural existence. Hybrid fractures have also not been considered so far as brittle element in paleostress reconstructions as their kinematic understanding was unclear. The Paleozoic Inkisi red sandstones of the West-Congo Supergroup in the region of Kinshasa and Brazzaville (Congo) are affected by prominent fracture sets, the most prominent of which are filled by palygorskite veins. They were formed in a strike-slip setting related to intraplate stress field generated by the mid Atlantic ridge push since that became efficient in late Cretaceous. We found an almost continuous range of fracture types, from plume joints to open fractures filled with calcite-palygorskite but without slip striae, and slickensided fractures with only thin films of redeposited palygorskite. The structural data have been analyzed with the Win-Tensor program (version 5.0.1) which has been adapted to consider hybrid fractures. Those are characterized by extension and shear, as opposed to tension fractures, on which no shear movement occurs, and to shear fractures, on which contraction occurs instead of extension. The results obtained suggest that the fractures have been initiated locally as plume joint and developed laterally under hybrid conditions. Later, some of them have been reactivated as strike-slip shear fractures and a new conjugated set appeared. Overall, this illustrates the progressive development with time of the stress state corresponding to an increase in the sigma

  7. A Thermoelastic Hydraulic Fracture Design Tool for Geothermal Reservoir Development

    SciTech Connect

    Ahmad Ghassemi

    2003-06-30

    Geothermal energy is recovered by circulating water through heat exchange areas within a hot rock mass. Geothermal reservoir rock masses generally consist of igneous and metamorphic rocks that have low matrix permeability. Therefore, cracks and fractures play a significant role in extraction of geothermal energy by providing the major pathways for fluid flow and heat exchange. Thus, knowledge of conditions leading to formation of fractures and fracture networks is of paramount importance. Furthermore, in the absence of natural fractures or adequate connectivity, artificial fracture are created in the reservoir using hydraulic fracturing. At times, the practice aims to create a number of parallel fractures connecting a pair of wells. Multiple fractures are preferred because of the large size necessary when using only a single fracture. Although the basic idea is rather simple, hydraulic fracturing is a complex process involving interactions of high pressure fluid injections with a stressed hot rock mass, mechanical interaction of induced fractures with existing natural fractures, and the spatial and temporal variations of in-situ stress. As a result it is necessary to develop tools that can be used to study these interactions as an integral part of a comprehensive approach to geothermal reservoir development, particularly enhanced geothermal systems. In response to this need we have set out to develop advanced thermo-mechanical models for design of artificial fractures and rock fracture research in geothermal reservoirs. These models consider the significant hydraulic and thermo-mechanical processes and their interaction with the in-situ stress state. Wellbore failure and fracture initiation is studied using a model that fully couples poro-mechanical and thermo-mechanical effects. The fracture propagation model is based on a complex variable and regular displacement discontinuity formulations. In the complex variable approach the displacement discontinuities are

  8. Persistent Ion Pairing in Aqueous Hydrochloric Acid

    SciTech Connect

    Baer, Marcel D.; Fulton, John L.; Balasubramanian, Mahalingam; Schenter, Gregory K.; Mundy, Christopher J.

    2014-07-03

    For strong acids, like hydrochloric acid, the complete dissociation into an excess proton and conjugated base as well as the formation of independent solvated charged fragments is assumed. The existence of a chloride-Hyronium (Cl-H3O+) contact ion pairs even in moderate concentration hydrochloric acid (2.5 m) demonstrates that the counter ions do not behave merely as spectators. Through the use of modern extended X-ray absorption fine structure (EXAFS) measurements in conjunction with state-of-the-art density functional theory (DFT) simulations, we are able to obtain an unprecedented view into the molecular structure of medium to high concentrated electrolytes. Here we report that the Cl-H3O+ contact ion pair structure persists throughout the entire concentration range studied and that these structures differ significantly from moieties studied in micro-solvated hydrochloric acid clusters. Characterizing distinct populations of these ion pairs gives rise to a novel molecular level description of how to think about the activity of the proton that impacts our picture of the pH scale. Funding for CJM, GKS, and JLF was provided by DOE Office of Science, Office of Basic Energy Science, Division of Chemical Sciences, Geosciences, and Biosciences. Funding for MDB was provided throught the Laboratory Directed Research and Development program at Pacific Northwest National Laboratory. MB was funded through Argonne National Laboratory.

  9. Electron Pairing Without Superconductivity

    NASA Astrophysics Data System (ADS)

    Levy, Jeremy; Cheng, G.; Tomczyk, M.; Lu, S.; Veazey, J. P.; Huang, M.; Irvin, P.; Ryu, S.; Lee, H.; Eom, C.-B.; Hellberg, C. S.

    2015-03-01

    Strontium titanate (SrTiO3) exhibits an extremely low carrier density threshold for superconductivity, and possesses a phase diagram similar to high-temperature superconductors--two factors that suggest an unconventional pairing mechanism. We describe transport experiments with nanowire-based quantum dots localized at the interface between SrTiO3 and LaAlO3. Electrostatic gating of the quantum dot reveals a series of two-electron conductance resonances--paired electron states--that bifurcate above a critical magnetic field Bp 1-4 Tesla, an order of magnitude larger than the superconducting critical magnetic field. For B Bp, the resonances exhibit a linear Zeeman-like energy splitting. Electron pairing is stable at temperatures as high as T = 900 mK, far above the superconducting transition temperature (Tc 300 mK). These experiments demonstrate the existence of a robust electronic phase in which electrons pair without forming a superconducting state. Key experimental signatures are captured by an attractive-U Hubbard model that describes real-space electron pairing as a precursor to superconductivity. This work was supported by ARO MURI W911NF-08-1-0317 (J.L.), AFOSR MURI FA9550-10-1-0524 (C.-B.E., J.L.) and FA9550-12-1-0342 (C.-B.E.), and grants from the National Science Foundation DMR-1104191 (J.L.), DMR.

  10. Induction logging device with a pair of mutually perpendicular bucking coils

    DOEpatents

    Koelle, Alfred R.; Landt, Jeremy A.

    1981-01-01

    An instrument is disclosed for mapping vertical conductive fractures in a resistive bedrock, magnetically inducing eddy currents by a pair of vertically oriented, mutually perpendicular, coplanar coils. The eddy currents drive magnetic fields which are picked up by a second, similar pair of coils.

  11. Supernovae in paired galaxies

    NASA Astrophysics Data System (ADS)

    Nazaryan, T. A.; Petrosian, A. R.; Hakobyan, A. A.; Adibekyan, V. Zh.; Kunth, D.; Mamon, G. A.; Turatto, M.; Aramyan, L. S.

    2014-07-01

    We investigate the influence of close neighbor galaxies on the properties of supernovae (SNe) and their host galaxies using 56 SNe located in pairs of galaxies with different levels of star formation (SF) and nuclear activity. The mean distance of type II SNe from nuclei of hosts is greater by about a factor of 2 than that of type Ibc SNe. The distributions and mean distances of SNe are consistent with previous results compiled with the larger sample. For the first time it is shown that SNe Ibc are located in pairs with significantly smaller difference of radial velocities between components than pairs containing SNe Ia and II. We consider this as a result of higher star formation rate (SFR) of these closer systems of galaxies.

  12. Applications of balanced pairs

    NASA Astrophysics Data System (ADS)

    Li, HuanHuan; Wang, JunFu; Huang, ZhaoYong

    2016-05-01

    Let $(\\mathscr{X}$, $\\mathscr{Y})$ be a balanced pair in an abelian category. We first introduce the notion of cotorsion pairs relative to $(\\mathscr{X}$, $\\mathscr{Y})$, and then give some equivalent characterizations when a relative cotorsion pair is hereditary or perfect. We prove that if the $\\mathscr{X}$-resolution dimension of $\\mathscr{Y}$ (resp. $\\mathscr{Y}$-coresolution dimension of $\\mathscr{X}$) is finite, then the bounded homotopy category of $\\mathscr{Y}$ (resp. $\\mathscr{X}$) is contained in that of $\\mathscr{X}$ (resp. $\\mathscr{Y}$). As a consequence, we get that the right $\\mathscr{X}$-singularity category coincides with the left $\\mathscr{Y}$-singularity category if the $\\mathscr{X}$-resolution dimension of $\\mathscr{Y}$ and the $\\mathscr{Y}$-coresolution dimension of $\\mathscr{X}$ are finite.

  13. Paratrooper's Ankle Fracture: Posterior Malleolar Fracture

    PubMed Central

    Young, Ki Won; Cho, Jae Ho; Kim, Hyung Seuk; Cho, Hun Ki; Lee, Kyung Tai

    2015-01-01

    Background We assessed the frequency and types of ankle fractures that frequently occur during parachute landings of special operation unit personnel and analyzed the causes. Methods Fifty-six members of the special force brigade of the military who had sustained ankle fractures during parachute landings between January 2005 and April 2010 were retrospectively analyzed. The injury sites and fracture sites were identified and the fracture types were categorized by the Lauge-Hansen and Weber classifications. Follow-up surveys were performed with respect to the American Orthopedic Foot and Ankle Society ankle-hindfoot score, patient satisfaction, and return to preinjury activity. Results The patients were all males with a mean age of 23.6 years. There were 28 right and 28 left ankle fractures. Twenty-two patients had simple fractures and 34 patients had comminuted fractures. The average number of injury and fractures sites per person was 2.07 (116 injuries including a syndesmosis injury and a deltoid injury) and 1.75 (98 fracture sites), respectively. Twenty-three cases (41.07%) were accompanied by posterior malleolar fractures. Fifty-five patients underwent surgery; of these, 30 had plate internal fixations. Weber type A, B, and C fractures were found in 4, 38, and 14 cases, respectively. Based on the Lauge-Hansen classification, supination-external rotation injuries were found in 20 cases, supination-adduction injuries in 22 cases, pronation-external rotation injuries in 11 cases, tibiofibular fractures in 2 cases, and simple medial malleolar fractures in 2 cases. The mean follow-up period was 23.8 months, and the average follow-up American Orthopedic Foot and Ankle Society ankle-hindfoot score was 85.42. Forty-five patients (80.36%) reported excellent or good satisfaction with the outcome. Conclusions Posterior malleolar fractures occurred in 41.07% of ankle fractures sustained in parachute landings. Because most of the ankle fractures in parachute injuries were

  14. π-conjugation and conformation in a semiconducting polymer: small angle x-ray scattering study

    NASA Astrophysics Data System (ADS)

    Choudhury, Paramita Kar; Bagchi, Debjani; Menon, Reghu

    2009-05-01

    Small angle x-ray scattering (SAXS) in a poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) solution has shown the important role of π-electron conjugation in controlling the chain conformation and assembly. By increasing the extent of conjugation from 30 to 100%, the persistence length (lp) increases from 20 to 66 Å. Moreover, a pronounced second peak in the pair distribution function has been observed in a fully conjugated chain, at larger length scales. This feature indicates that the chain segments tend to self-assemble as the conjugation along the chain increases. Xylene enhances the rigidity of the PPV backbone to yield extended structures, while tetrahydrofuran solvates the side groups to form compact coils in which the lp is much shorter.

  15. Fracture sealing utilising microbially induced carbonate precipitation

    NASA Astrophysics Data System (ADS)

    Moir, H.; El Mountassir, G.; Lunn, R. J.; Gilfillan, L. J.

    2011-12-01

    Predicting and controlling spatial and temporal variations in fracture flow properties is of considerable importance to the nuclear waste disposal, carbon capture and storage, and hydrocarbon industries. Fractures and faults provide pathways which may allow the migration of contaminants from depth to the surface. The hydraulic properties of fractures are governed by the interactions between the evolving stress field and the continuous precipitation and dissolution of minerals transported via subsurface fluids. Fractures may be subject to multiple mineralisation episodes, between which they may seal completely before being subject to further shear failure or they may remain open pathways for fluid flow and contaminant transport. We investigate experimentally the spatial and temporal evolution of carbonate precipitation in fractures. We use microbially mediated reactions to reproduce precipitation events similar to those that may be found in fractured rocks. A series of laboratory experiments was carried out using transparent idealised fracture networks to investigate how repeated carbonate precipitation events result in spatial and temporal evolution of the fracture aperture distribution. Both staged and continuous flow experiments were carried out and the effect of chemical and bacterial concentrations were explored to find the most efficient test procedure. Fractures were represented as a series of precision-etched parallel channels between a pair of sealed Perspex plates. Multiple channels were designed to maintain a constant flow rate, whilst independently adjusting channel aperture and width to explore the effects of aperture and fluid velocity on biomineral precipitation. The results from these experiments show that both velocity and aperture have important effects on precipitation patterns and rates. For a given flow rate, narrow aperture channels exhibit increased precipitation. Within wide fractures, the pattern of precipitation over time is such that flow

  16. Oligonucleotide conjugates for therapeutic applications

    PubMed Central

    Winkler, Johannes

    2013-01-01

    Insufficient pharmacokinetic properties and poor cellular uptake are the main hurdles for successful therapeutic development of oligonucleotide agents. The covalent attachment of various ligands designed to influence the biodistribution and cellular uptake or for targeting specific tissues is an attractive possibility to advance therapeutic applications and to expand development options. In contrast to advanced formulations, which often consist of multiple reagents and are sensitive to a variety of preparation conditions, oligonucleotide conjugates are defined molecules, enabling structure-based analytics and quality control techniques. This review gives an overview of current developments of oligonucleotide conjugates for therapeutic applications. Attached ligands comprise peptides, proteins, carbohydrates, aptamers and small molecules, including cholesterol, tocopherol and folic acid. Important linkage types and conjugation methods are summarized. The distinct ligands directly influence biochemical parameters, uptake machanisms and pharmacokinetic properties. PMID:23883124

  17. Multi-pair states in electron-positron pair creation

    NASA Astrophysics Data System (ADS)

    Wöllert, Anton; Bauke, Heiko; Keitel, Christoph H.

    2016-09-01

    Ultra strong electromagnetic fields can lead to spontaneous creation of single or multiple electron-positron pairs. A quantum field theoretical treatment of the pair creation process combined with numerical methods provides a description of the fermionic quantum field state, from which all observables of the multiple electron-positron pairs can be inferred. This allows to study the complex multi-particle dynamics of electron-positron pair creation in-depth, including multi-pair statistics as well as momentum distributions and spin. To illustrate the potential benefit of this approach, it is applied to the intermediate regime of pair creation between nonperturbative Schwinger pair creation and perturbative multiphoton pair creation where the creation of multi-pair states becomes nonnegligible but cascades do not yet set in. Furthermore, it is demonstrated how spin and helicity of the created electrons and positrons are affected by the polarization of the counterpropagating laser fields, which induce the creation of electron-positron pairs.

  18. Epidemiology of fragility fractures.

    PubMed

    Friedman, Susan M; Mendelson, Daniel Ari

    2014-05-01

    As the world population of older adults-in particular those over age 85-increases, the incidence of fragility fractures will also increase. It is predicted that the worldwide incidence of hip fractures will grow to 6.3 million yearly by 2050. Fractures result in significant financial and personal costs. Older adults who sustain fractures are at risk for functional decline and mortality, both as a function of fractures and their complications and of the frailty of the patients who sustain fractures. Identifying individuals at high risk provides an opportunity for both primary and secondary prevention. PMID:24721358

  19. Controls on natural fracture variability in the Southern Raton Basin of Colorado and New Mexico.

    SciTech Connect

    Keefe, Russell G.; Cooper, Scott Patrick; Herrin, James M.; Larson, Rich; Lorenz, John Clay; Basinski, Paul M.; Olsson, William Arthur

    2004-07-01

    Natural fractures in Jurassic through Tertiary rock units of the Raton Basin locally contain conjugate shear fractures that are mechanically compatible with associated extension fractures, i.e., they have a bisector to the acute angle that is parallel to the strike of associated extension fractures, normal to the thrust front at the western margin of the basin. Both sets of fractures are therefore interpreted to have formed during Laramide-age thrusting from west to east that formed the Sangre de Cristo Mountains and subsequently the foreland Raton Basin, and that imposed strong east-west compressive stresses onto the strata filling the basin. This pattern is not universal, however. Anomalous NNE-SSW striking fractures locally dominate strata close to the thrust front, and fracture patterns are irregular in strata associated with anticlinal structures within the basin. Of special interest are strike-slip style conjugate shear fractures within Dakota Sandstone outcrops 60 miles to the east of the thrust front. Mohr-Coulomb failure diagrams are utilized to describe how these formed as well as how two distinctly different types of fractures can be formed in the same basin under the same regional tectonic setting and at the same time. The primary controls in this interpretation are simply the mechanical properties of the specific rock units and the depth of burial rather than significant changes in the applied stress.

  20. Defined DNA/nanoparticle conjugates

    NASA Astrophysics Data System (ADS)

    Ackerson, Christopher J.; Sykes, Michael T.; Kornberg, Roger D.

    2005-09-01

    Glutathione monolayer-protected gold clusters were reacted by place exchange with 19- or 20-residue thiolated oligonucleotides. The resulting DNA/nanoparticle conjugates could be separated on the basis of the number of bound oligonucleotides by gel electrophoresis and assembled with one another by DNA-DNA hybridization. This approach overcomes previous limitations of DNA/nanoparticle synthesis and yields conjugates that are precisely defined with respect to both gold and nucleic acid content. Freely available online through the PNAS open access option.

  1. Site-specific gene modification by PNAs conjugated to psoralen.

    PubMed

    Kim, Ki-Hyun; Nielsen, Peter E; Glazer, Peter M

    2006-01-10

    DNA-binding molecules, including triplex-forming oligonucleotides (TFOs) and peptide nucleic acids (PNAs), can be utilized to introduce site-specific mutations or to promote recombination at selected genomic sites. To further evaluate the utility of PNAs for site-specific gene modification, we tested dimeric bis-PNAs conjugated to psoralen. These PNAs are designed to form a triplex-invasion complex within the supF reporter gene in an episomal shuttle vector and to direct site-specific photoadduct formation by the conjugated psoralen. The psoralen-bis-PNA conjugate was found to direct photoadduct formation to the intended 5'-TpA base step next to the PNA-binding site, and the photoadduct formation efficiency displayed both concentration and UVA irradiation dependence. The effect of PNA-targeted photoadducts in a mammalian system was tested by SV40-based shuttle vector assay. After in vitro binding, we found that photoadducts directed by PNAs conjugated to psoralen-induced mutations at frequencies in the range of 0.46%, 6.5-fold above the background. In a protocol for intracellular gene targeting in the episomal shuttle vector, the psoralen-PNA-induced mutation frequency was 0.13%, 3.5-fold higher than the background. Most of the induced mutations were deletions and single-base-pair substitutions at or adjacent to the targeted PNA-binding and photoadduct-formation sites. When the results are taken together, they demonstrate the ability of bis-PNAs conjugated with psoralen to mediate site-specific gene modification, and they further support the development of PNAs as tools for gene-targeting applications. PMID:16388608

  2. Antibody conjugates with unnatural amino acids.

    PubMed

    Hallam, Trevor J; Wold, Erik; Wahl, Alan; Smider, Vaughn V

    2015-06-01

    Antibody conjugates are important in many areas of medicine and biological research, and antibody-drug conjugates (ADCs) are becoming an important next generation class of therapeutics for cancer treatment. Early conjugation technologies relied upon random conjugation to multiple amino acid side chains, resulting in heterogeneous mixtures of labeled antibody. Recent studies, however, strongly support the notion that site-specific conjugation produces a homogeneous population of antibody conjugates with improved pharmacologic properties over randomly coupled molecules. Genetically incorporated unnatural amino acids (uAAs) allow unique orthogonal coupling strategies compared to those used for the 20 naturally occurring amino acids. Thus, uAAs provide a novel paradigm for creation of next generation ADCs. Additionally, uAA-based site-specific conjugation could also empower creation of additional multifunctional conjugates important as biopharmaceuticals, diagnostics, or reagents. PMID:25898256

  3. Infant skull fracture (image)

    MedlinePlus

    Skull fractures may occur with head injuries. Although the skull is both tough and resilient and provides excellent ... or blow can result in fracture of the skull and may be accompanied by injury to the ...

  4. Fractures in anisotropic media

    NASA Astrophysics Data System (ADS)

    Shao, Siyi

    Rocks may be composed of layers and contain fracture sets that cause the hydraulic, mechanical and seismic properties of a rock to be anisotropic. Coexisting fractures and layers in rock give rise to competing mechanisms of anisotropy. For example: (1) at low fracture stiffness, apparent shear-wave anisotropy induced by matrix layering can be masked or enhanced by the presence of a fracture, depending on the fracture orientation with respect to layering, and (2) compressional-wave guided modes generated by parallel fractures can also mask the presence of matrix layerings for particular fracture orientations and fracture specific stiffness. This report focuses on two anisotropic sources that are widely encountered in rock engineering: fractures (mechanical discontinuity) and matrix layering (impedance discontinuity), by investigating: (1) matrix property characterization, i.e., to determine elastic constants in anisotropic solids, (2) interface wave behavior in single-fractured anisotropic media, (3) compressional wave guided modes in parallel-fractured anisotropic media (single fracture orientation) and (4) the elastic response of orthogonal fracture networks. Elastic constants of a medium are required to understand and quantify wave propagation in anisotropic media but are affected by fractures and matrix properties. Experimental observations and analytical analysis demonstrate that behaviors of both fracture interface waves and compressional-wave guided modes for fractures in anisotropic media, are affected by fracture specific stiffness (controlled by external stresses), signal frequency and relative orientation between layerings in the matrix and fractures. A fractured layered medium exhibits: (1) fracture-dominated anisotropy when the fractures are weakly coupled; (2) isotropic behavior when fractures delay waves that are usually fast in a layered medium; and (3) matrix-dominated anisotropy when the fractures are closed and no longer delay the signal. The

  5. Hip fracture surgery

    MedlinePlus

    ... neck fracture repair; Trochanteric fracture repair; Hip pinning surgery; Osteoarthritis-hip ... You may receive general anesthesia before this surgery. This means ... spinal anesthesia. With this kind of anesthesia, medicine is ...

  6. Bone fracture repair - slideshow

    MedlinePlus

    ... page: //medlineplus.gov/ency/presentations/100077.htm Bone fracture repair - series To use the sharing features on ... to slide 4 out of 4 Indications Overview Fractures of the bones are classified in a number ...

  7. Forearm Fractures in Children

    MedlinePlus

    .org Forearm Fractures in Children The forearm is the part of the arm between the wrist and the elbow. It is ... two bones: the radius and the ulna. Forearm fractures are common in childhood, accounting for more than ...

  8. Nasal fracture - aftercare

    MedlinePlus

    ... page: //medlineplus.gov/ency/patientinstructions/000554.htm Nasal fracture - aftercare To use the sharing features on this ... that gives your nose its shape. A nasal fracture occurs when the bony part of your nose ...

  9. Nasal fracture (image)

    MedlinePlus

    A nasal fracture is a break in the bone over the ridge of the nose. It usually results from a blunt ... and is one of the most common facial fracture. Symptoms of a broken nose include pain, blood ...

  10. Microwave-assisted isomerisation of lactose to lactulose and Maillard conjugation of lactulose and lactose with whey proteins and peptides.

    PubMed

    Nooshkam, Majid; Madadlou, Ashkan

    2016-06-01

    Lactose was isomerised to lactulose by microwave heating and purified by a methanolic procedure to a product with approximately 72% lactulose content. Afterwards, lactose and the lactulose-rich product (PLu) were conjugated with either whey protein isolate (WPI) or its antioxidant hydrolysate (WPH) through microwaving. Lactose had a higher Maillard reactivity than PLu, and WPH was more reactive than WPI. The browning intensity of WPI-sugar systems was however higher than that of WPH-sugar pairs. Atomic force microscopy showed larger (up to ≈103 nm) particles for WPI-PLu conjugates compared to WPH-PLu counterparts (up to ≈39 nm). The Maillard conjugation progressively increased the radical-scavenging activity of WPI/WPH-sugar pairs with increasing conjugation time and improved the foaming properties of WPI and WPH. The WPI/WPH-sugar conjugates showed higher solubility and emulsification index than unreacted counterpart pairs. For native WPI, β-lactoglobulin was not degraded by in vitro gastric digestion, whereas for WPH-PLu conjugates degraded completely. PMID:26830553

  11. Pediatric Open Fractures.

    PubMed

    Trionfo, Arianna; Cavanaugh, Priscilla K; Herman, Martin J

    2016-07-01

    Open fractures in children are rare and are typically associated with better prognoses compared with their adult equivalents. Regardless, open fractures pose a challenge because of the risk of healing complications and infection, leading to significant morbidity even in the pediatric population. Therefore, the management of pediatric open fractures requires special consideration. This article comprehensively reviews the initial evaluation, classification, treatment, outcomes, and controversies of open fractures in children. PMID:27241379

  12. Protected Flux Pairing Qubit

    NASA Astrophysics Data System (ADS)

    Bell, Matthew; Zhang, Wenyuan; Ioffe, Lev; Gershenson, Michael

    2014-03-01

    We have studied the coherent flux tunneling in a qubit containing two submicron Josephson junctions shunted by a superinductor (a dissipationless inductor with an impedance much greater than the resistance quantum). The two low energy quantum states of this device, 0 and 1, are represented by even and odd number of fluxes in the loop, respectively. This device is dual to the charge pairing Josephson rhombi qubit. The spectrum of the device, studied by microwave spectroscopy, reflects the interference between coherent quantum phase slips in the two junctions (the Aharonov-Casher effect). The time domain measurements demonstrate the suppression of the qubit's energy relaxation in the protected regime, which illustrates the potential of this flux pairing device as a protected quantum circuit. Templeton Foundation, NSF, and ARO.

  13. Effect of bonded gold inlays on fracture resistance of teeth.

    PubMed

    Eakle, W S; Staninec, M

    1992-06-01

    The purpose of this study was to determine if bonding gold inlays to tooth structure with an adhesive resin cement would increase the fracture resistance of restored teeth. Extracted paired maxillary premolars were prepared for mesio-occlusodistal inlays, and the inlays were cast in type II gold. In one tooth of each pair, the inlay was sandblasted with aluminium oxide, tin plated, and cemented with an adhesive resin into the etched preparation. For the other (control) tooth in each pair, the inlay was sandblasted and then cemented into the preparation with zinc phosphate cement. The teeth were thermocycled and loaded until fracture. The teeth in the bonded group had a statistically significantly higher fracture resistance than did the teeth in the control group. Scanning electron microscopic examination revealed that failure in the bonded group occurred predominantly within the resin. PMID:1502322

  14. Orderings for conjugate gradient preconditionings

    NASA Technical Reports Server (NTRS)

    Ortega, James M.

    1991-01-01

    The effect of orderings on the rate of convergence of the conjugate gradient method with SSOR or incomplete Cholesky preconditioning is examined. Some results also are presented that help to explain why red/black ordering gives an inferior rate of convergence.

  15. Antibody-drug conjugate payloads.

    PubMed

    Anderl, Jan; Faulstich, Heinz; Hechler, Torsten; Kulke, Michael

    2013-01-01

    Toxin payloads, or drugs, are the crucial components of therapeutic antibody-drug conjugates (ADCs). This review will give an introduction on the requirements that make a toxic compound suitable to be used in an antitumoral ADC and will summarize the structural and mechanistic features of four drug families that yielded promising results in preclinical and clinical studies. PMID:23913141

  16. Enhanced photophysics of conjugated polymers

    DOEpatents

    Chen, Liaohai

    2007-06-12

    A particulate fluorescent conjugated polymer surfactant complex and method of making and using same. The particles are between about 15 and about 50 nm and when formed from a lipsome surfactant have a charge density similar to DNA and are strongly absorbed by cancer cells.

  17. Bacteriophytochromes control conjugation in Agrobacterium fabrum.

    PubMed

    Bai, Yingnan; Rottwinkel, Gregor; Feng, Juan; Liu, Yiyao; Lamparter, Tilman

    2016-08-01

    Bacterial conjugation, the transfer of single stranded plasmid DNA from donor to recipient cell, is mediated through the type IV secretion system. We performed conjugation assays using a transmissible artificial plasmid as reporter. With this assay, conjugation in Agrobacterium fabrum was modulated by the phytochromes Agp1 and Agp2, photoreceptors that are most sensitive in the red region of visible light. In conjugation studies with wild-type donor cells carrying a pBIN-GUSINT plasmid as reporter that lacked the Ti (tumor inducing) plasmid, no conjugation was observed. When either agp1(-) or agp2(-) knockout donor strains were used, plasmid DNA was delivered to the recipient, indicating that both phytochromes suppress conjugation in the wild type donor. In the recipient strains, the loss of Agp1 or Agp2 led to diminished conjugation. When wild type cells with Ti plasmid and pBIN-GUS reporter plasmid were used as donor, a high rate of conjugation was observed. The DNA transfer was down regulated by red or far-red light by a factor of 3.5. With agp1(-) or agp2(-) knockout donor cells, conjugation in the dark was about 10 times lower than with the wild type donor, and with the double knockout donor no conjugation was observed. These results imply that the phytochrome system has evolved to inhibit conjugation in the light. The decrease of conjugation under different temperature correlated with the decrease of phytochrome autophosphorylation. PMID:27261700

  18. Fractured tooth (image)

    MedlinePlus

    A tooth can be chipped or fractured during an accident or a bad fall. A tooth that is chipped or not badly fractured can usually be handled on a nonemergency basis. A tooth that is badly fractured may have exposed nerve ...

  19. Waterflood-induced fractures

    SciTech Connect

    Dikken, B.J.; Niko, H.

    1987-01-01

    Fracturing occurs quite often in water injection wells, with sometimes unforeseen consequences on waterflood sweep efficiency. One of the causes of fracturing is often the cooling of hot formations by cold injection water. A special version of a thermal reservoir simulator for prototype applications has thus been constructed that is capable of dealing with propagating waterflood-induces hydraulic fractures. With this simulator, fracture propagation and the effect of growing fractures on the sweep efficiency are studied. Infinite fracture conductivity is assumed. The limitation to a very high leak-off fractures justifies disregarding the changes in fracture volume. Fracture growth is calculated using the concept of a critical stress intensity factor. Both poro- and thermo-elastic changes in the horizontal stresses are calculated numerically and their influence on the fracture initiation/propagation is continuously taken into account. In addition, a model of fracture wall impairment because of filter-cake build-up due to poor quality injection water is included. Results are presented for both thermal and isothermal situations. It is observed in isothermal cases that the voidage replacement ratio (volume balance during injection) determined to a great extent the length to which the fracture eventually may grow.

  20. Fracture Risk among Nursing Home Residents Initiating Antipsychotic Medications

    PubMed Central

    Rigler, Sally K.; Shireman, Theresa I.; Cook-Wiens, Galen J.; Ellerbeck, Edward F.; Whittle, Jeffrey C.; Mehr, David R.; Mahnken, Jonathan D.

    2013-01-01

    Objectives to determine whether antipsychotic medication initiation is associated with subsequent fracture in nursing home residents, whether fracture rates differ between first-generation versus second-generation antipsychotic use, and whether fracture rates differ among users of haloperidol, risperidone, olanzapine, and quetiapine. Design time-to-event analyses were conducted in a retrospective cohort using linked Medicaid, Medicare, Minimum Data Set and Online Survey, Certification and Reporting data sets. Setting and Participants nursing home residents aged ≥ 65 years in CA, FL, MO, NJ and PA. Measurements fracture outcomes (any fracture; hip fracture) in first-versus second-generation antipsychotic users, and specifically among users of haloperidol, risperidone, olanzapine and quetiapine. Comparisons incorporated propensity scores that included patient-level variables (demographics, comorbidity, diagnoses, weight, fall history, concomitant medications, cognitive performance, physical function, aggressivebehavior) and facility-level variables (nursing home size, ownership factors, staffing levels). Results Among 8,262 subjects (within 4,131 pairs), 4.3% suffered any fracture during observation with 1% having a hip fracture during an average follow up period of 93 ± 71 days; range 1 to 293 days). Antipsychotic initiation was associated with any fracture (hazard ratio (HR) 1.39, p=0.004) and with hip fracture (HR 1.76, p=0.024). The highest risk was found for hip fracture when antipsychotic use was adjusted for dose(HR=2.96; p=0.008). However, no differences in time-to-fracture were found in first-versus second-generation agents or across competing individual drugs. Conclusion Antipsychotic initiation is associated with fracture in nursing home residents, but risk does not differ across commonly used antipsychotics. PMID:23590366

  1. Real-space representation of electron correlation in π-conjugated systems

    SciTech Connect

    Wang, Jian E-mail: e.j.baerends@vu.nl; Baerends, Evert Jan E-mail: e.j.baerends@vu.nl

    2015-05-28

    π-electron conjugation and aromaticity are commonly associated with delocalization and especially high mobility of the π electrons. We investigate if also the electron correlation (pair density) exhibits signatures of the special electronic structure of conjugated systems. To that end the shape and extent of the pair density and derived quantities (exchange-correlation hole, Coulomb hole, and conditional density) are investigated for the prototype systems ethylene, hexatriene, and benzene. The answer is that the effects of π electron conjugation are hardly discernible in the real space representations of the electron correlation. We find the xc hole to be as localized (confined to atomic or diatomic regions) in conjugated systems as in small molecules. This result is relevant for density functional theory (DFT). The potential of the electron exchange-correlation hole is the largest part of v{sub xc}, the exchange-correlation Kohn-Sham potential. So the extent of the hole directly affects the orbital energies of both occupied and unoccupied Kohn-Sham orbitals and therefore has direct relevance for the excitation spectrum as calculated with time-dependent DFT calculations. The potential of the localized xc hole is comparatively more attractive than the actual hole left behind by an electron excited from a delocalized molecular orbital of a conjugated system.

  2. Effect of bonded amalgam on the fracture resistance of teeth.

    PubMed

    Eakle, W S; Staninec, M; Lacy, A M

    1992-08-01

    The purpose of this study was to determine whether amalgam bonded to tooth structure with an adhesive resin cement can increase the fracture resistance of restored teeth. Extracted paired upper premolars were prepared for G.V. Black type mesioocclusodistal amalgam restorations. In one tooth of each pair (the experimental group), the enamel walls were etched with phosphoric acid and were painted with an adhesive resin (Panavia), and amalgam was condensed and carved. For the other tooth in each pair (the control group), amalgam was placed in the same manner but was not etched and lined with resin. The teeth were thermocycled and mounted for testing and then were loaded until fracture. A significant difference (p less than 0.05, the paired Student's t-test) was found in the force needed to fracture the bonded amalgam group (70.5 +/- 21.6 kg) compared with that needed to fracture the conventional amalgam group (60.3 +/- 16.8 kg). SEM examination of fractures at the interface occurred predominantly within the resin. PMID:1501170

  3. Talus fractures: surgical principles.

    PubMed

    Rush, Shannon M; Jennings, Meagan; Hamilton, Graham A

    2009-01-01

    Surgical treatment of talus fractures can challenge even the most skilled foot and ankle surgeon. Complicated fracture patterns combined with joint dislocation of variable degrees require accurate assessment, sound understanding of principles of fracture care, and broad command of internal fixation techniques needed for successful surgical care. Elimination of unnecessary soft tissue dissection, a low threshold for surgical reduction, liberal use of malleolar osteotomy to expose body fracture, and detailed attention to fracture reduction and joint alignment are critical to the success of treatment. Even with the best surgical care complications are common and seem to correlate with injury severity and open injuries. PMID:19121756

  4. Phase transition in conjugated oligomers suspended in chloroform

    NASA Astrophysics Data System (ADS)

    Dwivedi, Shikha; Kumar, Anupam; Yadav, S. N. S.; Mishra, Pankaj

    2015-08-01

    Density functional theory (DFT) has been used to investigate the isotropic-nematic (I-N) phase transition in a system of high aspect ratio conjugated oligomers suspended in chloroform. The interaction between the oligomers is modeled using Gay-Berne potential in which effect of solvent is implicit. Percus-Yevick integral equation theory has been used to evaluate the pair correlation functions of the fluid phase at several temperatures and densities. These pair correlation function has been used in the DFT to evaluate the I-N freezing parameters. Highly oriented nematic is found to stabilize at low density. The results obtained are in qualitative agreement with the simulation and are verifiable.

  5. Multiphoton- and simultaneous conjugate Ramsey-Borde atom interferometers

    SciTech Connect

    Mueller, Holger; Chiow, Sheng-wey; Herrmann, Sven; Chu, Steven

    2008-03-06

    We report on our experiment to measure h/M, the ratio of the Planck constant to the mass of Cs atoms, and thereby the fine-structure constant. The target accuracy is 1 part per billion or better. We focus on two recent milestones: (i) The first realization of atom interferometers based on light-pulse beam splitters that transfer the momentum of up to 12 photon pairs, which increases the useful signal (matter wave phase shift) by a factor of 144 compared to the beam splitters used in the best present atom interferometers. Moreover, they lead to a cancellation of important systematic effects. (ii) The first realization of a simultaneous pair of conjugate Ramsey-Borde interferometers. In these, the relative sign of the inertial term is reversed so that it can be cancelled. Simultaneous operation means that this holds for a time-dependent inertial term (vibrations) too, which promises a substantial improvement in the signal to noise ratio.

  6. Existence of best proximity pairs and equilibrium pairs

    NASA Astrophysics Data System (ADS)

    Kim, Won Kyu; Lee, Kyoung Hee

    2006-04-01

    In this paper, using the fixed point theorem for Kakutani factorizable multifunctions, we shall prove new existence theorems of best proximity pairs and equilibrium pairs for free abstract economies, which include the previous fixed point theorems and equilibrium existence theorems.

  7. Epidemiology of clavicle fractures.

    PubMed

    Postacchini, Franco; Gumina, Stefano; De Santis, Pierfrancesco; Albo, Francesco

    2002-01-01

    An epidemiologic study of 535 isolated clavicle fractures treated in a hospital of a large metropolis during an 11-year period was performed. Data regarding patient's age and sex, side involved, mechanism of injury, and season in which the fracture occurred were obtained from the clinical records. Radiographic classification was performed with the Allman system. Clavicle fractures represented 2.6% of all fractures and 44% of those in the shoulder girdle. Most patients were men (68%), and the left side was involved in 61% of cases. Fractures of the middle third of the clavicle, which were the most common (81%), were displaced in 48% of cases and comminuted in 19%. Fractures of the medial third were the least common (2%). The prevalence of midclavicular fractures was found to decrease progressively with age, starting from the first decade of life when they represented 88.2% of all clavicle fractures and were undisplaced in 55.5% of cases. In adults, the incidence of displaced fractures, independent of location, was higher than that of undisplaced fractures. Traffic accidents were the most common cause of the injury. In the period under study, the incidence of fractures showed no significant change over time and no seasonal variation. PMID:12378163

  8. Mechanics of Hydraulic Fractures

    NASA Astrophysics Data System (ADS)

    Detournay, Emmanuel

    2016-01-01

    Hydraulic fractures represent a particular class of tensile fractures that propagate in solid media under pre-existing compressive stresses as a result of internal pressurization by an injected viscous fluid. The main application of engineered hydraulic fractures is the stimulation of oil and gas wells to increase production. Several physical processes affect the propagation of these fractures, including the flow of viscous fluid, creation of solid surfaces, and leak-off of fracturing fluid. The interplay and the competition between these processes lead to multiple length scales and timescales in the system, which reveal the shifting influence of the far-field stress, viscous dissipation, fracture energy, and leak-off as the fracture propagates.

  9. Conjugative Plasmids of Neisseria gonorrhoeae

    PubMed Central

    Pachulec, Emilia; van der Does, Chris

    2010-01-01

    Many clinical isolates of the human pathogen Neisseria gonorrhoeae contain conjugative plasmids. The host range of these plasmids is limited to Neisseria species, but presence of a tetracycline (tetM) determinant inserted in several of these plasmids is an important cause of the rapid spread of tetracycline resistance. Previously plasmids with different backbones (Dutch and American type backbones) and with and without different tetM determinants (Dutch and American type tetM determinants) have been identified. Within the isolates tested, all plasmids with American or Dutch type tetM determinants contained a Dutch type plasmid backbone. This demonstrated that tetM determinants should not be used to differentiate between conjugal plasmid backbones. The nucleotide sequences of conjugative plasmids with Dutch type plasmid backbones either not containing the tetM determinant (pEP5233) or containing Dutch (pEP5289) or American (pEP5050) type tetM determinants were determined. Analysis of the backbone sequences showed that they belong to a novel IncP1 subfamily divergent from the IncP1α, β, γ, δ and ε subfamilies. The tetM determinants were inserted in a genetic load region found in all these plasmids. Insertion was accompanied by the insertion of a gene with an unknown function, and rearrangement of a toxin/antitoxin gene cluster. The genetic load region contains two toxin/antitoxins of the Zeta/Epsilon toxin/antitoxin family previously only found in Gram positive organisms and the virulence associated protein D of the VapD/VapX toxin/antitoxin family. Remarkably, presence of VapX of pJD1, a small cryptic neisserial plasmid, in the acceptor strain strongly increased the conjugation efficiency, suggesting that it functions as an antitoxin for the conjugative plasmid. The presence of the toxin and antitoxin on different plasmids might explain why the host range of this IncP1 plasmid is limited to Neisseria species. The isolated plasmids conjugated efficiently between

  10. Self-organizing conjugated polymers

    NASA Astrophysics Data System (ADS)

    Hong, Xiaoyong Michael

    2000-10-01

    A general and efficient synthetic route to semifluoroalkyl substituted thiophenes has been developed and a series of 3-semifluoroalkylthiophenes were synthesized. The lengths of the fluorocarbon chain and hydrocarbon spacer between thiophene and fluorocarbon were systematically altered to study their effect on the properties of the resulting polymers. Oxidative polymerization (FeCl3) and electrochemical polymerization of 3-semifluoroalkylthiophenes afforded regiorandom (head-to-tail coupling ˜70%) homopolymers. The solubility and thermal transition temperatures of the polymers are also dependent on the nature of side chains. The surface properties of the polymers are also a function of the length of fluoroalkyl side chains. From x-ray diffraction, the regiorandom polymers have low crystallinity. Two synthetic methods have been successfully utilized to prepare regioregular poly(3-semifluoroalkylthiophene)s (head-to-tail coupling >90%) and gave identical polymers. The regioregular polymers are highly conjugated and highly ordered. The long side chain substituted polythiophenes form a liquid crystal mesophase between the crystal solid and isotropic liquid phases. To prepare polymers bearing alternating 3-semifluoroalkylthiophene and alkylthiophene units, we developed synthetic methods to 3-semifluoroalkyl-4 '-alkyl-2,2'-bithiophenes. The 3-semifluoroalkyl-4 '-alkyl-2,2'-bithiophenes were polymerized to afford regiorandom and regioregular polymers. Regiorandom polymers have low crystallinity and conjugation. Regioregular, strictly alternating copolymer with 3-semifluoroalkylthiophene and alkylthiophene units are highly conjugated and ordered. The regioregular polymers self-assemble into bilayer structure in solid state due to phase separation between fluorocarbon and hydrocarbon. At high temperatures close to melting transition, the thiophene rings rotate and twist along the molecular axis to give a single layer structure. Methylene bridges were placed between the

  11. Multistate Switches: Ruthenium Alkynyl-Dihydroazulene/Vinylheptafulvene Conjugates.

    PubMed

    Vlasceanu, Alexandru; Andersen, Cecilie L; Parker, Christian R; Hammerich, Ole; Morsing, Thorbjørn J; Jevric, Martyn; Lindbaek Broman, Søren; Kadziola, Anders; Nielsen, Mogens Brøndsted

    2016-05-23

    Multimode molecular switches incorporating distinct and independently addressable functional components have potential applications as advanced switches and logic gates for molecular electronics and memory storage devices. Herein, we describe the synthesis and characterization of four switches based on the dihydroazulene/vinylheptafulvene (DHA/VHF) photo/thermoswitch pair functionalized with the ruthenium-based Cp*(dppe)Ru ([Ru*]) metal complex (dppe=1,2-bis(diphenylphosphino)ethane; Cp*=pentamethylcyclopentadienyl). The [Ru*]-DHA conjugates can potentially exist in six different states accessible by alternation between DHA/VHF, Ru(II) /Ru(III) , and alkynyl/vinylidene, which can be individually stimulated by using light/heat, oxidation/reduction, and acid/base. Access to the full range of states was found to be strongly dependent on the electronic communication between the metal center and the organic photoswitch in these [Ru*]-DHA conjugates. Detailed electrochemical, spectroscopic (UV/Vis, IR, NMR), and X-ray crystallographic studies indeed reveal significant electronic interactions between the two moieties. When in direct conjugation, the ruthenium metal center was found to quench the photochemical ring-opening of DHA, which in one case could be restored by protonation or oxidation, allowing conversion to the VHF state. PMID:27114110

  12. Impact of hip fracture on mortality: a cohort study in hip fracture discordant identical twins.

    PubMed

    Michaëlsson, Karl; Nordström, Peter; Nordström, Anna; Garmo, Hans; Byberg, Liisa; Pedersen, Nancy L; Melhus, Håkan

    2014-02-01

    Several studies have shown a long-lasting higher mortality after hip fracture, but the reasons for the excess risk are not well understood. We aimed to determine whether a higher mortality after hip fracture exists when controlling for genetic constitution, shared environment, comorbidity, and lifestyle by use of a nationwide cohort study in hip fracture discordant monozygotic twins. All 286 identical Swedish twin pairs discordant for hip fracture (1972 to 2010) were identified. Comorbidity and lifestyle information was retrieved by registers and questionnaire information. We used intrapair Cox regression to compute multivariable-adjusted hazard ratios (HRs) for death. During follow-up, 143 twins with a hip fracture died (50%) compared with 101 twins (35%) without a hip fracture. Through the first year after hip fracture, the rate of death increased fourfold in women (HR = 3.71; 95% confidence interval [CI] 1.32-10.40) and sevenfold in men (HR = 6.67; 95% CI 1.47-30.13). The increased rate in women only persisted during the first year after hip fracture (HR after 1 year = 0.99; 95% CI 0.66-1.50), whereas the corresponding HR in men was 2.58 (95% CI 1.02-6.62). The higher risk in men after the hip fracture event was successively attenuated during follow-up. After 5 years, the hazard ratio in men with a hip fracture was 1.19 (95% CI 0.29-4.90). On average, the hip fracture contributed to 0.9 years of life lost in women (95% CI 0.06-1.7) and 2.7 years in men (95% CI 1.7-3.7). The potential years of life lost associated with the hip fracture was especially pronounced in older men (>75 years), with an average loss of 47% (95% CI 31-61) of the expected remaining lifetime. We conclude that both women and men display a higher mortality after hip fracture independent of genes, comorbidity, and lifestyle. PMID:23821464

  13. Conjugation in Hyalophysa chattoni Bradbury (Apostomatida): An adaptation to a symbiotic life cycle.

    PubMed

    Bradbury, Phyllis Clarke; Hash, Stephen M; Rogers, Faye Kucera; Neptun, Steven H; Zhang, Limin

    2013-11-01

    Hyalophysa chattoni, borne as an encysted phoront on a crustacean's exoskeleton, metamorphoses to the trophont during the host's premolt. After the molt within 15min to 2h conjugants with food vacuoles appear in the exuvium, swimming along with the trophonts. Starvation in other ciliates usually precedes conjugation, but food vacuoles in conjugants do not preclude starvation. Only after ingestion and dehydration of vacuoles ceases, does digestion of exuvial fluid begin. Conjugants resorb their feeding apparatus as they fuse. A single imperforate membrane from each partner forms the junction membrane. In a reproductive cyst conjugants divide synchronously, but now the junction membrane is interrupted by pores and channels. After the last division the daughters undergo meiosis--two meiotic divisions and one mitotic division yielding two prokarya as they simultaneously differentiate into tomites. After fertilization, pairs separate and the synkaryon divides once into a macronuclear anlage and a micronucleus. Exconjugants leave the cyst and seek a host. The parental macronucleus remains active until the phoront stage when the anlage develops. Owing to random association of micronuclei during meiosis, Hyalophysa's exconjugants are more genetically diverse than exconjugants from conventional patterns of conjugation. PMID:23706651

  14. The ISG15 conjugation system.

    PubMed

    Durfee, Larissa A; Huibregtse, Jon M

    2012-01-01

    ISG15 is a ubiquitin-like modifier that is expressed in response to type 1 interferon signaling (IFN-α/β) and plays a role in antiviral responses. The core E1, E2, and E3 enzymes for ISG15 are Ube1L, UbcH8, and Herc5, respectively, and these are all also induced at the transcriptional level by IFN-α/β. We recently showed that Herc5 associates with polysomes and modifies target proteins in a cotranslational manner. Here, we describe the expression of the core conjugating enzymes in human cells, the detection of ISG15 conjugates, and the methods for fractionation of Herc5 with polysomes. PMID:22350882

  15. Single conjugated polymer nanoparticle capacitors

    NASA Astrophysics Data System (ADS)

    Palacios, Rodrigo E.; Lee, Kwang-Jik; Rival, Arnaud; Adachi, Takuji; Bolinger, Joshua C.; Fradkin, Leonid; Barbara, Paul F.

    2009-02-01

    The hole injection from a carbazole derivative hole transport layer into nanoparticles ( r = 25 ± 15 nm) of the conjugated polymer MEH-PPV was investigated by an indirect single-particle fluorescence-quenching technique. The results suggest that there is a kinetic barrier for hole injection that prevents polymer particles from being charged in the dark. This barrier can be overcome with the assistance of optical excitation of the MEH-PPV nanoparticles, achieving a thermodynamic population of injected holes at positive bias. The amount of injected holes at equilibrium is observed to depend upon the bias in a manner highly consistent with device simulations based on a continuum model. Overall, the results demonstrate that the hole injection into nano domains of conjugated polymers is a complex process depending upon molecular interfacial effects determined by device geometry and electrostatic interactions.

  16. Enhanced photophysics of conjugated polymers

    DOEpatents

    Chen, Liaohai; Xu, Su; McBranch, Duncan; Whitten, David

    2003-05-27

    The addition of oppositely charged surfactant to fluorescent ionic conjugated polymer forms a polymer-surfactant complex that exhibits at least one improved photophysical property. The conjugated polymer is a fluorescent ionic polymer that typically has at least one ionic side chain or moiety that interacts with the specific surfactant selected. The photophysical property improvements may include increased fluorescence quantum efficiency, wavelength-independent emission and absorption spectra, and more stable fluorescence decay kinetics. The complexation typically occurs in a solution of a polar solvent in which the polymer and surfactant are soluble, but it may also occur in a mixture of solvents. The solution is commonly prepared with a surfactant molecule:monomer repeat unit of polymer ratio ranging from about 1:100 to about 1:1. A polymer-surfactant complex precipitate is formed as the ratio approaches 1:1. This precipitate is recoverable and usable in many forms.

  17. Fiber bundle phase conjugate mirror

    SciTech Connect

    Ward, Benjamin G.

    2012-05-01

    An improved method and apparatus for passively conjugating the phases of a distorted wavefronts resulting from optical phase mismatch between elements of a fiber laser array are disclosed. A method for passively conjugating a distorted wavefront comprises the steps of: multiplexing a plurality of probe fibers and a bundle pump fiber in a fiber bundle array; passing the multiplexed output from the fiber bundle array through a collimating lens and into one portion of a non-linear medium; passing the output from a pump collection fiber through a focusing lens and into another portion of the non-linear medium so that the output from the pump collection fiber mixes with the multiplexed output from the fiber bundle; adjusting one or more degrees of freedom of one or more of the fiber bundle array, the collimating lens, the focusing lens, the non-linear medium, or the pump collection fiber to produce a standing wave in the non-linear medium.

  18. Modeling of Interaction of Hydraulic Fractures in Complex Fracture Networks

    NASA Astrophysics Data System (ADS)

    Kresse, O. 2; Wu, R.; Weng, X.; Gu, H.; Cohen, C.

    2011-12-01

    A recently developed unconventional fracture model (UFM) is able to simulate complex fracture network propagation in a formation with pre-existing natural fractures. Multiple fracture branches can propagate at the same time and intersect/cross each other. Each open fracture exerts additional stresses on the surrounding rock and adjacent fractures, which is often referred to as "stress shadow" effect. The stress shadow can cause significant restriction of fracture width, leading to greater risk of proppant screenout. It can also alter the fracture propagation path and drastically affect fracture network patterns. It is hence critical to properly model the fracture interaction in a complex fracture model. A method for computing the stress shadow in a complex hydraulic fracture network is presented. The method is based on an enhanced 2D Displacement Discontinuity Method (DDM) with correction for finite fracture height. The computed stress field is compared to 3D numerical simulation in a few simple examples and shows the method provides a good approximation for the 3D fracture problem. This stress shadow calculation is incorporated in the UFM. The results for simple cases of two fractures are presented that show the fractures can either attract or expel each other depending on their initial relative positions, and compares favorably with an independent 2D non-planar hydraulic fracture model. Additional examples of both planar and complex fractures propagating from multiple perforation clusters are presented, showing that fracture interaction controls the fracture dimension and propagation pattern. In a formation with no or small stress anisotropy, fracture interaction can lead to dramatic divergence of the fractures as they tend to repel each other. However, when stress anisotropy is large, the fracture propagation direction is dominated by the stress field and fracture turning due to fracture interaction is limited. However, stress shadowing still has a strong effect

  19. Computer Simulation of Fracture in Aerogels

    NASA Technical Reports Server (NTRS)

    Good, Brian S.

    2006-01-01

    Aerogels are of interest to the aerospace community primarily for their thermal properties, notably their low thermal conductivities. While the gels are typically fragile, recent advances in the application of conformal polymer layers to these gels has made them potentially useful as lightweight structural materials as well. In this work, we investigate the strength and fracture behavior of silica aerogels using a molecular statics-based computer simulation technique. The gels' structure is simulated via a Diffusion Limited Cluster Aggregation (DLCA) algorithm, which produces fractal structures representing experimentally observed aggregates of so-called secondary particles, themselves composed of amorphous silica primary particles an order of magnitude smaller. We have performed multi-length-scale simulations of fracture in silica aerogels, in which the interaction b e e n two secondary particles is assumed to be described by a Morse pair potential parameterized such that the potential range is much smaller than the secondary particle size. These Morse parameters are obtained by atomistic simulation of models of the experimentally-observed amorphous silica "bridges," with the fracture behavior of these bridges modeled via molecular statics using a Morse/Coulomb potential for silica. We consider the energetics of the fracture, and compare qualitative features of low-and high-density gel fracture.

  20. Fracture corridors in carbonates

    NASA Astrophysics Data System (ADS)

    Chatelée, Sébastien; Lamarche, Juliette; Gauthier, Bertrand D. M.

    2015-04-01

    Among fractures, Fracture Corridors (FC) are anomalous structures made of highly persistent fracture clusters having a strong effect on multi-phase fluid flow in the subsurface. While mechanical and geological conditions for diffuse fracture systems are well constrained, FC genetic conditions remain a matter of questioning. FC can be localized in larger structures such as folds and fault zones but recent studies suggest that a large amount of fractures and FC also arise as distributed in the host rock and formed in tabular layers during burial with early rock mechanical differentiation. In addition, while the mechanical stratigraphy is of prime importance for fracture stratigraphy, it is still unknown which factor prevails on FC genesis among the local versus regional stress-state, the host rock mechanical stratigraphy or the sedimentary facies. We present a study of fractures in a 400×300 m wide quarry (Calvisson, SE France) dug in homogeneous marly limestones of Hauterivian age. The quarry exhibits diffuse fractures as well as 16 FC. The aim of this study is to reveal the genetics factor for FC development, their global geometry and internal morphologic variations, but also to clear the impact of fracture corridors on diffuse fracture. For that, we measured >2500 fractures (strike, dip, spacing, filling, aperture, etc.) and studied microstructures in 80 thin sections. We calculated fracture density and acquired LiDAR data with >90 million points with a resolution of 4 to 15mm. Diffuse fractures are organized as two perpendicular sets, a main set NE-SW-trending and minor set NW-SE-trending. The FC have the same trend, but the NW-SE trend prevail on the NE-SW one. The LiDAR acquisition allows to visualize the 3D lateral continuity with corridors with a minimal extension of 30m. We distinguish 4 internal morphologic types in FC, depending on fracture morphology, occurrence of breccia and number of zones. The types may occur in a single FC with a lateral transition

  1. Generation of spatially correlated fracture models for seismic simulations

    NASA Astrophysics Data System (ADS)

    Shekhar, Ravi; Gibson, Richard L., Jr.

    2011-04-01

    The critical geometrical parameters that quantify the spatial distribution of natural fractures are the orientation, length and position of fractures. Knowledge of their spatial distribution is important as they control the movement of subsurface fluids and also influence seismic waves propagating in the subsurface. However, generating realistic models of all of these geometrical parameters to use in forward seismic modelling or inversion applications can become very difficult, especially when constraints are available only at a few sparse well locations. Hence, this provides strong motivation for applying seismic data to estimate these quantities in field settings, and reliable seismic modelling provides important constraints for interpretation and inversion. The Discrete Fracture Network (DFN) approach has been used frequently to generate models with stochastic distributions of fractures based on sparse well and seismic data. However, most of these studies lack any constraint from physical models of the behaviour of fractured media. In this paper, we implement and extend an alternative modelling technique to generate several realizations of a fracture model beginning with theoretical results for the strain energy of a fractured material and propose ways to better incorporate geological field observations. The method utilizes an elastic energy function that sums the interactions of all pairs of fractures present in the model. The energy for each pair depends on the distance between the two fractures, their orientations, lengths and some material properties. This energy function also serves as an objective function for a simulated annealing (SA) algorithm used to obtain multiple realizations of correlated fracture networks. We improve earlier versions of this technique by incorporating periodic boundary conditions, including criteria to limit the maximum range of pair-wise calculations and suggesting methods to constrain models to match field data. Assuming that

  2. Variable metric conjugate gradient methods

    SciTech Connect

    Barth, T.; Manteuffel, T.

    1994-07-01

    1.1 Motivation. In this paper we present a framework that includes many well known iterative methods for the solution of nonsymmetric linear systems of equations, Ax = b. Section 2 begins with a brief review of the conjugate gradient method. Next, we describe a broader class of methods, known as projection methods, to which the conjugate gradient (CG) method and most conjugate gradient-like methods belong. The concept of a method having either a fixed or a variable metric is introduced. Methods that have a metric are referred to as either fixed or variable metric methods. Some relationships between projection methods and fixed (variable) metric methods are discussed. The main emphasis of the remainder of this paper is on variable metric methods. In Section 3 we show how the biconjugate gradient (BCG), and the quasi-minimal residual (QMR) methods fit into this framework as variable metric methods. By modifying the underlying Lanczos biorthogonalization process used in the implementation of BCG and QMR, we obtain other variable metric methods. These, we refer to as generalizations of BCG and QMR.

  3. Stress fractures in athletes.

    PubMed

    Hulkko, A; Orava, S

    1987-06-01

    During the 14-year period of 1971-1985, 368 stress fractures in 324 athletes were treated. The series contained 268 fractures in males and 100 fractures in females; 32 fractures occurred in children (less than 16 years), 117 in adolescents (16-19 years), and 219 in adults. Forty-six fractures were incurred by athletes at an international level, 274 by athletes at a national or district level and 48 by recreational athletes. Of the total cases, 72% occurred to runners and a further 12% to athletes in other sports after running exercises. The distribution of the stress fractures by site was: tibia 182, metatarsal bones 73, fibula 44, big toe sesamoid bones 15, femoral shaft 14, femoral neck 9, tarsal navicular 9, pelvis 7, olecranon 5 and other bones 10. Of the total fractures, 342 were treated conservatively and 26 fractures required surgical treatment. The operative indication was dislocation in 5 cases and delayed union/nonunion in 21 cases. The sites most often affected by delayed union were: anterior midtibia, sesamoid bones of the big toe, base of the fifth metatarsal, olecranon, and tarsal navicular. The athletes at an international level experienced the greatest risk of multiple separate fractures, protracted healing, or fractures requiring surgery. PMID:3623785

  4. Multiprocessor switch with selective pairing

    SciTech Connect

    Gara, Alan; Gschwind, Michael K; Salapura, Valentina

    2014-03-11

    System, method and computer program product for a multiprocessing system to offer selective pairing of processor cores for increased processing reliability. A selective pairing facility is provided that selectively connects, i.e., pairs, multiple microprocessor or processor cores to provide one highly reliable thread (or thread group). Each paired microprocessor or processor cores that provide one highly reliable thread for high-reliability connect with a system components such as a memory "nest" (or memory hierarchy), an optional system controller, and optional interrupt controller, optional I/O or peripheral devices, etc. The memory nest is attached to a selective pairing facility via a switch or a bus

  5. Growth, children, and fractures.

    PubMed

    Jones, Graeme

    2004-09-01

    Fractures in childhood have long been considered an unavoidable consequence of growth. Studies in recent years have documented the epidemiology of these very common fractures and have also documented considerable variation by fracture type and from country to country. There have also been a number of studies aimed at identifying risk factors particularly for the most common distal forearm fracture. These studies have consistently associated bone mineral density with these fractures. Other possible risk factors include obesity, physical inactivity, sports, cola beverages, calcium intake, risk taking, and coordination. While prospective studies are required to confirm these risk factors, accumulating evidence now suggests that a substantial proportion of fractures in children are preventable. PMID:16036086

  6. [Trochanteric femoral fractures].

    PubMed

    Douša, P; Čech, O; Weissinger, M; Džupa, V

    2013-01-01

    At the present time proximal femoral fractures account for 30% of all fractures referred to hospitals for treatment. Our population is ageing, the proportion of patients with post-menopausal or senile osteoporosis is increasing and therefore the number of proximal femoral fractures requiring urgent treatment is growing too. In the age category of 50 years and older, the incidence of these fractures has increased exponentially. Our department serves as a trauma centre for half of Prague and part of the Central Bohemia Region with a population of 1 150 000. Prague in particular has a high number of elderly citizens. Our experience is based on extensive clinical data obtained from the Register of Proximal Femoral Fractures established in 1997. During 14 years, 4280 patients, 3112 women and 1168 men, were admitted to our department for treatment of proximal femoral fractures. All patients were followed up until healing or development of complications. In the group under study, 82% were patients older than 70 years; 72% of those requiring surgery were in their seventies and eighties. Men were significantly younger than women (p<0.001) and represented 30% of the group. The fractures were 2.3-times more frequent in women than in men. In the category under 60 years, men significantly outnumbered women (p<0.001). The patients with pertrochanteric fractures were, on the average, eight years older than the patients with intertrochanteric fractures, which is a significant difference (p<0.001). The mortality rate within a year of injury was about 30%. Trochanteric fractures accounted for 54.7% and femoral neck fractures for 45.3% of all fractures. The inter-annual increase was 5.9%, with more trochanteric than femoral neck fractures. There was a non-significant decrease in intertrochanteric (AO 31-A3) fractures. On the other hand, the number of pertrochanteric (AO 31-A1+2) fractures increased significantly (p<0.001). A total of 1 394 fractures were treated with a proximal

  7. Multiple origins of asteroid pairs

    NASA Astrophysics Data System (ADS)

    Jacobson, Seth A.

    2016-01-01

    Rotationally fissioned asteroids produce unbound asteroid pairs that have very similar heliocentric orbits. Backward integration of their current heliocentric orbits provides an age of closest proximity that can be used to date the rotational fission event. Most asteroid pairs follow a predicted theoretical relationship between the primary spin period and the mass ratio of the two pair members that is a direct consequence of the YORP-induced rotational fission hypothesis. If the progenitor asteroid has strength, asteroid pairs may have higher mass ratios or faster rotating primaries. However, the process of secondary fission leaves the originally predicted trend unaltered. We also describe the characteristics of pair members produced by four alternative routes from a rotational fission event to an asteroid pair. Unlike direct formation from the event itself, the age of closest proximity of these pairs cannot generally be used to date the rotational fission event since considerable time may have passed.

  8. Fracture tooth fragment reattachment

    PubMed Central

    Maitin, Nitin; Maitin, Shipra Nangalia; Rastogi, Khushboo; Bhushan, Rajarshi

    2013-01-01

    Coronal fractures of the anterior teeth are a common form of dental trauma and its sequelae may impair the establishment and accomplishment of an adequate treatment plan. Among the various treatment options, reattachment of a crown fragment is a conservative treatment that should be considered for crown fractures of anterior teeth. This clinical case reports the management of two coronal tooth fracture cases that were successfully treated using tooth fragment reattachment using glass-fibre-reinforced composite post. PMID:23853012

  9. Fracture detection logging tool

    DOEpatents

    Benzing, William M.

    1992-06-09

    A method and apparatus by which fractured rock formations are identified and their orientation may be determined includes two orthogonal motion sensors which are used in conjunction with a downhole orbital vibrator. The downhole vibrator includes a device for orienting the sensors. The output of the sensors is displayed as a lissajou figure. The shape of the figure changes when a subsurface fracture is encountered in the borehole. The apparatus and method identifies fractures rock formations and enables the azimuthal orientation of the fractures to be determined.

  10. Capitellar and Trochlear Fractures.

    PubMed

    Carroll, Michael J; Athwal, George S; King, Graham J W; Faber, Kenneth J

    2015-11-01

    Fractures of the capitellum and trochlea account for a small proportion of elbow trauma. Clinicians need to be vigilant in their assessment as they are commonly associated with other injuries about the elbow. To optimize outcomes, the goals of management include a stable, anatomic reduction and early range of motion. Closed reduction of noncomminuted fractures may be successful but requires close follow-up. Open reduction and internal fixation is the preferred management of displaced capitellum-trochlear fractures. Elbow stiffness is the most commonly reported complication in operatively treated fractures. Arthroscopic-assisted reduction and internal fixation and arthroplasty are evolving management options. PMID:26498550

  11. Pathological fractures in children

    PubMed Central

    De Mattos, C. B. R.; Binitie, O.; Dormans, J. P.

    2012-01-01

    Pathological fractures in children can occur as a result of a variety of conditions, ranging from metabolic diseases and infection to tumours. Fractures through benign and malignant bone tumours should be recognised and managed appropriately by the treating orthopaedic surgeon. The most common benign bone tumours that cause pathological fractures in children are unicameral bone cysts, aneurysmal bone cysts, non-ossifying fibromas and fibrous dysplasia. Although pathological fractures through a primary bone malignancy are rare, these should be recognised quickly in order to achieve better outcomes. A thorough history, physical examination and review of plain radiographs are crucial to determine the cause and guide treatment. In most benign cases the fracture will heal and the lesion can be addressed at the time of the fracture, or after the fracture is healed. A step-wise and multidisciplinary approach is necessary in caring for paediatric patients with malignancies. Pathological fractures do not have to be treated by amputation; these fractures can heal and limb salvage can be performed when indicated. PMID:23610658

  12. Pterygoid Plate Fractures: Not Limited to Le Fort Fractures.

    PubMed

    Garg, Ravi K; Alsheik, Nila H; Afifi, Ahmed M; Gentry, Lindell R

    2015-09-01

    Pterygoid plate fractures are often described in the setting of Le Fort fractures. The goal of this study was to define other craniofacial fracture patterns causing injury to the pterygoid plates. A retrospective review of computed tomography (CT) scans obtained on craniofacial trauma patients over a 5-year period revealed 209 patients with pterygoid plate fractures. Pterygoid plate fractures in 78 patients (37.3%) were unrelated to Le Fort fractures. Common causes included sphenotemporal buttress fractures in 26 patients (33.3%), temporal bone fractures in 18 patients (23.1%), zygomaticomaxillary complex fractures in 17 patients (21.8%), and displaced mandible fractures in 14 patients (17.9%). These findings indicate that approximately one third of pterygoid plate fractures do not result from Le Fort pattern injuries and that the craniofacial surgeon should have a broad differential for causes of pterygoid plate fractures when reviewing trauma imaging. PMID:26147022

  13. Stereo Pair, Honolulu, Oahu

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Honolulu, on the island of Oahu, is a large and growing urban area. This stereoscopic image pair, combining a Landsat image with topography measured by the Shuttle Radar Topography Mission (SRTM), shows how topography controls the urban pattern. This color image can be viewed in 3-D by viewing the left image with the right eye and the right image with the left eye (cross-eyed viewing), or by downloading and printing the image pair, and viewing them with a stereoscope.

    Features of interest in this scene include Diamond Head (an extinct volcano near the bottom of the image), Waikiki Beach (just above Diamond Head), the Punchbowl National Cemetary (another extinct volcano, near the image center), downtown Honolulu and Honolulu harbor (image left-center), and offshore reef patterns. The slopes of the Koolau mountain range are seen in the right half of the image. Clouds commonly hang above ridges and peaks of the Hawaiian Islands, but in this synthesized stereo rendition appear draped directly on the mountains. The clouds are actually about 1000 meters (3300 feet) above sea level.

    This stereoscopic image pair was generated using topographic data from the Shuttle Radar Topography Mission, combined with a Landsat 7 Thematic Mapper image collected at the same time as the SRTM flight. The topography data were used to create two differing perspectives, one for each eye. When stereoscopically merged, the result is a vertically exaggerated view of the Earth's surface in its full three dimensions. The United States Geological Survey's Earth Resources Observations Systems (EROS) Data Center, Sioux Falls, South Dakota, provided the Landsat data.

    The Shuttle Radar Topography Mission (SRTM), launched on February 11, 2000, used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. The mission was designed to collect three-dimensional measurements of the

  14. Alternate formulation of enhanced backscattering as phase conjugation and diffraction: derivation and experimental observation

    PubMed Central

    Rogers, Jeremy D.; Stoyneva, Valentina; Turzhitsky, Vladimir; Mutyal, Nikhil N.; Pradhan, Prabhakar; Çapoğlu, İlker R.; Backman, Vadim

    2011-01-01

    Enhanced backscattering (EBS), also known as weak localization of light, is derived using the Huygens–Fresnel principle and backscattering is generally shown to be the sum of an incoherent baseline and a phase conjugated portion of the incident wave that forms EBS. The phase conjugated portion is truncated by an effective aperture described by the probability function P(s) of coherent path-pair separations. P(s) is determined by the scattering properties of the medium and so characterization of EBS can be used for metrology of scattering materials. A three dimensional intensity peak is predicted in free space at a point conjugate to the source and is experimentally observed. PMID:21716426

  15. Tuning the Electron Acceptor in Phthalocyanine-Based Electron Donor-Acceptor Conjugates.

    PubMed

    Sekita, Michael; Jiménez, Ángel J; Marcos, M Luisa; Caballero, Esmeralda; Rodríguez-Morgade, M Salomé; Guldi, Dirk M; Torres, Tomás

    2015-12-21

    Zinc phthalocyanines (ZnPc) have been attached to the peri-position of a perylenemonoimide (PMI) and a perylenemonoanhydride (PMA), affording electron donor-acceptor conjugates 1 and 2, respectively. In addition, a perylene-monoimide-monoanhydride (PMIMA) has been connected to a ZnPc through its imido position to yield the ZnPc-PMIMA conjugate 10. The three conjugates have been studied for photoinduced electron transfer. For ZnPc-PMIMA 10, electron transfer occurs upon both ZnPc and PMIMA excitation, giving rise to a long-lived (340 ps) charge-separated state. For ZnPc-PMI 1 and ZnPc-PMA 2, stabilization of the radical ion pair states by using polar media is necessary. In THF, photoexcitation of either ZnPc or PMI/PMA produces charge-separated states with lifetimes of 375 and 163 ps, respectively. PMID:26593778

  16. Stereo Pair, Pasadena, California

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This stereoscopic image pair is a perspective view that shows the western part of the city of Pasadena, California, looking north toward the San Gabriel Mountains. Portions of the cities of Altadena and La Canada Flintridge are also shown. The cluster of large buildings left of center, at the base of the mountains, is the Jet Propulsion Laboratory. This image shows the power of combining data from different sources to create planning tools to study problems that affect large urban areas. In addition to the well-known earthquake hazards, Southern California is affected by a natural cycle of fire and mudflows. Data shown in this image can be used to predict both how wildfires spread over the terrain and how mudflows are channeled down the canyons.

    The image was created from three datasets: the Shuttle Radar Topography Mission (SRTM) supplied the elevation, U. S. Geological Survey digital aerial photography provided the image detail, and the Landsat Thematic Mapper provided the color. The United States Geological Survey's Earth Resources Observations Systems (EROS) Data Center, Sioux Falls, South Dakota, provided the Landsat data and the aerial photography. The image can be viewed in 3-D by viewing the left image with the right eye and the right image with the left eye (cross-eyed viewing), or by downloading and printing the image pair, and viewing them with a stereoscope.

    The Shuttle Radar Topography Mission (SRTM), launched on February 11, 2000, used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. The mission was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, an additional C-band imaging antenna and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration

  17. Phononic Phase Conjugation in an Optomechanical System

    NASA Astrophysics Data System (ADS)

    Buchmann, Lukas; Wright, Ewan; Meystre, Pierre

    2013-05-01

    We study theoretically the phase conjugation of a phononic field in an optomechanical system with two mechanical modes coupled to a common optical field. Phase conjugation becomes the dominant process for an appropriate choice of driving field parameters, and he effective coupling coefficients between phonon modes can result in amplification and entanglement, phase-conjugation or a mixture thereof. We discuss surprising consequences of mechanical phase-conjugation that could lead to the preparation of mechanical states with negative temperature, the improvement of quantum memories and the study of the quantum-classical transition. Supported by DARPA ORCHID program.

  18. Enhanced optical phase conjugation in nonlinear metamaterials.

    PubMed

    Kim, Kihong

    2014-12-15

    Optical phase conjugation by degenerate four-wave mixing in nonlinear metamaterials is studied theoretically by solving the coupled wave equations using a generalized version of the invariant imbedding method. The phase-conjugate reflectance and the lateral shift of the phase-conjugate reflected beams are calculated and their dependencies on the frequency, the polarization, the incident angle, the material properties and the structure are investigated in detail. It is found that the efficiency of phase conjugation can be significantly enhanced due to the enhancement of electromagnetic fields in various metamaterial structures. PMID:25607488

  19. Linkers Having a Crucial Role in Antibody–Drug Conjugates

    PubMed Central

    Lu, Jun; Jiang, Feng; Lu, Aiping; Zhang, Ge

    2016-01-01

    Antibody–drug conjugates (ADCs) comprised of a desirable monoclonal antibody, an active cytotoxic drug and an appropriate linker are considered to be an innovative therapeutic approach for targeted treatment of various types of tumors and cancers, enhancing the therapeutic parameter of the cytotoxic drug and reducing the possibility of systemic cytotoxicity. An appropriate linker between the antibody and the cytotoxic drug provides a specific bridge, and thus helps the antibody to selectively deliver the cytotoxic drug to tumor cells and accurately releases the cytotoxic drug at tumor sites. In addition to conjugation, the linkers maintain ADCs’ stability during the preparation and storage stages of the ADCs and during the systemic circulation period. The design of linkers for ADCs is a challenge in terms of extracellular stability and intracellular release, and intracellular circumstances, such as the acid environment, the reducing environment and cathepsin, are considered as the catalysts to activate the triggers for initiating the cleavage of ADCs. This review discusses the linkers used in the clinical and marketing stages for ADCs and details the fracture modes of the linkers for the further development of ADCs. PMID:27089329

  20. Linkers Having a Crucial Role in Antibody-Drug Conjugates.

    PubMed

    Lu, Jun; Jiang, Feng; Lu, Aiping; Zhang, Ge

    2016-01-01

    Antibody-drug conjugates (ADCs) comprised of a desirable monoclonal antibody, an active cytotoxic drug and an appropriate linker are considered to be an innovative therapeutic approach for targeted treatment of various types of tumors and cancers, enhancing the therapeutic parameter of the cytotoxic drug and reducing the possibility of systemic cytotoxicity. An appropriate linker between the antibody and the cytotoxic drug provides a specific bridge, and thus helps the antibody to selectively deliver the cytotoxic drug to tumor cells and accurately releases the cytotoxic drug at tumor sites. In addition to conjugation, the linkers maintain ADCs' stability during the preparation and storage stages of the ADCs and during the systemic circulation period. The design of linkers for ADCs is a challenge in terms of extracellular stability and intracellular release, and intracellular circumstances, such as the acid environment, the reducing environment and cathepsin, are considered as the catalysts to activate the triggers for initiating the cleavage of ADCs. This review discusses the linkers used in the clinical and marketing stages for ADCs and details the fracture modes of the linkers for the further development of ADCs. PMID:27089329

  1. Phase conjugated slab laser designator

    SciTech Connect

    Chandra, S.; Paul, J.L.

    1989-06-06

    A laser designator is described comprising a laser pump means; a high power phase conjugated slab laser amplifier formed of GSGG:Cr:Nd as a lasing material on one side of the pump means; a low power rod shaped laser oscillator on the opposite side of the pump means; and a first plurality of optical reflecting and refracting means for directing and shaping a laser beam which surrounds the pump means and passes through the rod and slab; and a telescope means coupled to the beam to direct it to a distant target.

  2. Conjugative Transfer in Staphylococcus aureus.

    PubMed

    Halsey, Cortney R; Fey, Paul D

    2016-01-01

    The acquisition of plasmids has led to a significant increase in antimicrobial resistance within the staphylococci. In order to study these plasmids effectively, one must be able move the plasmid DNA into genetically clean backgrounds. While the smaller staphylococcal class I (1-5 kb) and class II (10-30 kb) plasmids are readily transferred using bacteriophage transduction or electroporation, these methods are inefficient at moving the larger class III (30-60 kb) plasmids. This review describes methods to transfer class III plasmids via conjugative mobilization. PMID:26194708

  3. The Role of Active Fractures on Borehole Breakout Development

    NASA Astrophysics Data System (ADS)

    Sahara, D.; Kohl, T.; Schoenball, M.; Müller, B.

    2013-12-01

    The properties of georeservoirs are strongly related to the stress field and their interpretation is a major target in geotechnical management. Borehole breakouts are direct indicators of the stress field as they develop due to the concentration of the highest compressional stress toward the minimum horizontal stress direction. However, the interaction with fractures might create local perturbations. Such weakened zones are often observed by localized anomalies of the borehole breakout orientation. We examined high-quality acoustic borehole televiewer (UBI) logs run in the entire granite sections at the deep well GPK4 at Soultz-sous-Forêts, France. The borehole is moderately inclined (15° - 35°) in its middle section. Detailed analysis of 1221 borehole elongation pairs in the vicinity of 1871 natural fractures observed in GPK4 well is used to infer the role of fractures on the borehole breakouts shape and orientation. Patterns of borehole breakout orientation in the vicinity of active fractures suggest that the wavelength of the borehole breakout orientation anomalies in this granite rock depend on the scale of the fracture while the rotation amplitude and direction is strongly influenced by the fracture orientation. In the upper and middle part of the well even a linear trend between fracture and breakout orientations could be established. In addition to the rotation, breakouts typically are found to be asymmetrically formed in zones of high fracture density. We find that major faults tend to create a systematic rotation of borehole breakout orientation with long spatial wavelength while abrupt changes are often observed around small fractures. The finding suggest that the borehole breakout heterogeneities are not merely governed by the principal stress heterogeneities, but that the effect of mechanical heterogeneities like elastic moduli changes, rock strength anisotropy and fracturing must be taken into account. Thus, one has to be careful to infer the

  4. Frustrated Lewis Pairs.

    PubMed

    Stephan, Douglas W

    2015-08-19

    The articulation of the notion of "frustrated Lewis pairs" (FLPs), which emerged from the discovery that H2 can be reversibly activated by combinations of sterically encumbered Lewis acids and bases, has prompted a great deal of recent activity. Perhaps the most remarkable consequence has been the development of FLP catalysts for the hydrogenation of a range of organic substrates. In the past 9 years, the substrate scope has evolved from bulky polar species to include a wide range of unsaturated organic molecules. In addition, effective stereoselective metal-free hydrogenation catalysts have begun to emerge. The mechanism of this activation of H2 has been explored, and the nature and range of Lewis acid/base combinations capable of effecting such activation have also expanded to include a variety of non-metal species. The reactivity of FLPs with a variety of other small molecules, including olefins, alkynes, and a range of element oxides, has also been developed. Although much of this latter chemistry has uncovered unique stoichiometric transformations, metal-free catalytic hydroamination, CO2 reduction chemistry, and applications in polymerization have also been achieved. The concept is also beginning to find applications in bioinorganic and materials chemistry as well as heterogeneous catalysis. This Perspective highlights many of these developments and discusses the relationship between FLPs and established chemistry. Some of the directions and developments that are likely to emerge from FLP chemistry in the future are also presented. PMID:26214241

  5. Pygmy stars: first pair.

    PubMed

    Zwicky, F

    1966-07-01

    The binary LP 101-15/16 having the proper motion of 1.62 seconds of arc per year has been studied with the prime-focus spectrograph of the 200-inch (508 cm) telescope. Indications are that LP 101-15/16 is the first pair of pygmy stars ever discovered. One of its components, LP 101-16, is probably a blue pygmy star which is at least four magnitudes fainter than the ordinary white dwarfs. Also, two of the Balmer lines in absorption appear to be displaced toward the red by amounts which indicate the existence of an Einstein gravitational red shift corresponding to about 1000 km sec-1. On the other hand LP 101-15 is red and shows an entirely new type of spectrum, which suggests that it may be a first representative of a type of red pygmy star which is 2.5 magnitudes fainter than the M-type dwarf stars of the main sequence. PMID:17730606

  6. Rib fracture - aftercare

    MedlinePlus

    A rib fracture is a crack or break in one or more of your rib bones. Your ribs are the round, flat bones in your chest ... A rib fracture can be very painful because your ribs move when you breathe, cough, and move your upper ...

  7. TIBIAL SHAFT FRACTURES

    PubMed Central

    Kojima, Kodi Edson; Ferreira, Ramon Venzon

    2015-01-01

    The long-bone fractures occur most frequently in the tibial shaft. Adequate treatment of such fractures avoids consolidation failure, skewed consolidation and reoperation. To classify these fractures, the AO/OTA classification method is still used, but it is worthwhile getting to know the Ellis classification method, which also includes assessment of soft-tissue injuries. There is often an association with compartmental syndrome, and early diagnosis can be achieved through evaluating clinical parameters and constant clinical monitoring. Once the diagnosis has been made, fasciotomy should be performed. It is always difficult to assess consolidation, but the RUST method may help in this. Radiography is assessed in two projections, and points are scored for the presence of the fracture line and a visible bone callus. Today, the dogma of six hours for cleaning the exposed fracture is under discussion. It is considered that an early start to intravenous antibiotic therapy and the lesion severity are very important. The question of early or late closure of the lesion in an exposed fracture has gone through several phases: sometimes early closure has been indicated and sometimes late closure. Currently, whenever possible, early closure of the lesion is recommended, since this diminishes the risk of infection. Milling of the canal when the intramedullary nail is introduced is still a controversial subject. Despite strong personal positions in favor of milling, studies have shown that there may be some advantage in relation to closed fractures, but not in exposed fractures. PMID:27026999

  8. Apparent capitellar fractures.

    PubMed

    Ring, David

    2007-11-01

    Isolated capitellar fractures are rare but are identified as such, even when they are more complex, because the displaced capitellar fracture is usually the most obvious and identifiable radiographic finding and because teaching has traditionally underemphasized the involvement of the trochlea in such fractures. The author prefers the term 'apparent capitellar fractures' and draws on his experience to explain why he favors three-dimensional CT for depicting fracture detail. This article discusses treatment options, emphasizing open reduction and internal fixation to restore the native elbow. Operative techniques, including extensile lateral exposure and olecranon osteotomy; fixation techniques; and elbow arthroplasty, are described. Complications, such as ulnar neuropathy and infection, are also covered. PMID:18054674

  9. Dynamic fracture mechanics

    NASA Technical Reports Server (NTRS)

    Kobayashi, A. S.; Ramulu, M.

    1985-01-01

    Dynamic fracture and crack propagation concepts for ductile materials are reviewed. The equations for calculating dynamic stress integrity and the dynamic energy release rate in order to study dynamic crack propagation are provided. The stress intensity factor versus crack velocity relation is investigated. The uses of optical experimental techniques and finite element methods for fracture analyses are described. The fracture criteria for a rapidly propagating crack under mixed mode conditions are discussed; crack extension and fracture criteria under combined tension and shear loading are based on maximum circumferential stress or energy criteria such as strain energy density. The development and use of a Dugdale model and finite element models to represent crack and fracture dynamics are examined.

  10. Transphyseal Distal Humerus Fracture.

    PubMed

    Abzug, Joshua; Ho, Christine Ann; Ritzman, Todd F; Brighton, Brian

    2016-01-01

    Transphyseal distal humerus fractures typically occur in children younger than 3 years secondary to birth trauma, nonaccidental trauma, or a fall from a small height. Prompt and accurate diagnosis of a transphyseal distal humerus fracture is crucial for a successful outcome. Recognizing that the forearm is not aligned with the humerus on plain radiographs may aid in the diagnosis of a transphyseal distal humerus fracture. Surgical management is most commonly performed with the aid of an arthrogram. Closed reduction and percutaneous pinning techniques similar to those used for supracondylar humerus fractures are employed. Cubitus varus caused by a malunion, osteonecrosis of the medial condyle, or growth arrest is the most common complication encountered in the treatment of transphyseal distal humerus fractures. A corrective lateral closing wedge osteotomy can be performed to restore a nearly normal carrying angle. PMID:27049206

  11. Lone pairs: an electrostatic viewpoint.

    PubMed

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

    2014-01-16

    A clear-cut definition of lone pairs has been offered in terms of characteristics of minima in molecular electrostatic potential (MESP). The largest eigenvalue and corresponding eigenvector of the Hessian at the minima are shown to distinguish lone pair regions from the other types of electron localization (such as π bonds). A comparative study of lone pairs as depicted by various other scalar fields such as the Laplacian of electron density and electron localization function is made. Further, an attempt has been made to generalize the definition of lone pairs to the case of cations. PMID:24372481

  12. Methods for Identifying Pair Halos

    NASA Astrophysics Data System (ADS)

    Wells, Brendan; Caputo, Regina; Atwood, William; Ritz, Steven M.

    2016-01-01

    The flux of very high energy gamma rays from active galactic nuclei (AGN) is attenuated via interactions with extragalactic background photons and is converted into e+e- pairs. With non-zero intergalactic magnetic fields, the electrons and positrons will deflect as they propagate and simultaneously lose energy by upscattering cosmic microwave background photons. "Pair halos," the visible consequences of these electromagnetic cascades, are faint and difficult to observe against their AGN counterparts. We investigate three methods for indirectly identifying pair halos, using a two-component approach to model the AGN core/halo image. We estimate each method's sensitivity by utilizing a new, detailed Monte Carlo pair-halo simulation.

  13. Controversies in kidney paired donation.

    PubMed

    Gentry, Sommer E; Montgomery, Robert A; Segev, Dorry L

    2012-07-01

    Kidney paired donation represented 10% of living kidney donation in the United States in 2011. National registries around the world and several separate registries in the United States arrange paired donations, although with significant variations in their practices. Concerns about ethical considerations, clinical advisability, and the quantitative effectiveness of these approaches in paired donation result in these variations. For instance, although donor travel can be burdensome and might discourage paired donation, it was nearly universal until convincing analysis showed that living donor kidneys can sustain many hours of cold ischemia time without adverse consequences. Opinions also differ about whether the last donor in a chain of paired donation transplants initiated by a nondirected donor should donate immediately to someone on the deceased donor wait-list (a domino or closed chain) or should be asked to wait some length of time and donate to start another sequence of paired donations later (an open chain); some argue that asking the donor to donate later may be coercive, and others focus on balancing the probability that the waiting donor withdraws versus the number of additional transplants if the chain can be continued. Other controversies in paired donation include simultaneous versus nonsimultaneous donor operations, whether to enroll compatible pairs, and interactions with desensitization protocols. Efforts to expand public awareness of and participation in paired donation are needed to generate more transplant opportunities. PMID:22732046

  14. Subgap Absorption in Conjugated Polymers

    DOE R&D Accomplishments Database

    Sinclair, M.; Seager, C. H.; McBranch, D.; Heeger, A. J; Baker, G. L.

    1991-01-01

    Along with X{sup (3)}, the magnitude of the optical absorption in the transparent window below the principal absorption edge is an important parameter which will ultimately determine the utility of conjugated polymers in active integrated optical devices. With an absorptance sensitivity of < 10{sup {minus}5}, Photothermal Deflection Spectroscopy (PDS) is ideal for determining the absorption coefficients of thin films of transparent'' materials. We have used PDS to measure the optical absorption spectra of the conjugated polymers poly(1,4-phenylene-vinylene) (and derivitives) and polydiacetylene-4BCMU in the spectral region from 0.55 eV to 3 eV. Our spectra show that the shape of the absorption edge varies considerably from polymer to polymer, with polydiacetylene-4BCMU having the steepest absorption edge. The minimum absorption coefficients measured varied somewhat with sample age and quality, but were typically in the range 1 cm{sup {minus}1} to 10 cm{sup {minus}1}. In the region below 1 eV, overtones of C-H stretching modes were observed, indicating that further improvements in transparency in this spectral region might be achieved via deuteration of fluorination.

  15. Solution assembly of conjugated polymers

    NASA Astrophysics Data System (ADS)

    Bokel, Felicia A.

    This dissertation focuses on the solution-state polymer assembly of conjugated polymers with specific attention to nano- and molecular-scale morphology. Understanding how to control these structures holds potential for applications in polymer-based electronics. Optimization of conjugated polymer morphology was performed with three objectives: 1) segregation of donor and acceptor materials on the nanometer length-scale, 2) achieving molecular-scale ordering in terms of crystallinity within distinct domains, and 3) maximizing the number and quality of well-defined donor/acceptor interfaces. Chapter 1 introduces the development of a mixed solvent method to create crystalline poly(3-hexyl thiophene) (P3HT) fibrils in solution. Chapter 2 describes fibril purification and approaches to robust and functional fibrils, while chapters 3 and 4 demonstrate the formation of hybrid nanocomposite wires of P3HT and cadmium selenide (CdSe) nanoparticles by two methods: 1) co-crystallization of free and P3HT-grafted CdSe for composite nanowires and 2) direct attachment of CdSe nanoparticles at fibril edges to give superhighway structures. These composite structures show great potential in the application of optoelectronic devices, such as the active layer of solar cells. Finally, ultrafast photophysical characterization of these polymers, using time-resolved photoluminescence and transient absorption, was performed to determine the aggregation types present in suspended fibrils and monitor the formation and decay of charged species in fibrils and donor-acceptor systems.

  16. Operational mechanism of conjugated polyelectrolytes.

    PubMed

    Tordera, Daniel; Kuik, Martijn; Rengert, Zachary D; Bandiello, Enrico; Bolink, Henk J; Bazan, Guillermo C; Nguyen, Thuc-Quyen

    2014-06-18

    Conjugated polyelectrolytes (CPEs) are versatile materials used in a range of organic optoelectronic applications. Because of their ionic/electronic nature, characterizing these materials is nontrivial, and their operational mechanism is not fully understood. In this work we use a methodology that combines constant-voltage-driven current-density transient measurements with fast current vs voltage scans to allow decoupling of ionic and electronic phenomena. This technique is applied to diodes prepared with cationic CPEs having different charge-compensating anions. Our results indicate that the operational mechanism of these devices is governed by electrochemical doping of the CPE. On the basis of the notion that the saturated depletion layer for the anions consists of the same π-conjugated backbone material, we discern how the extent and speed of formation of the doped region depend on the anion structure. Apart from addressing fundamental transport questions, this work provides a tool for future characterization of different CPEs and other similar systems. PMID:24855971

  17. Photoluminescence of Conjugated Star Polymers

    NASA Astrophysics Data System (ADS)

    Ferguson, J. B.; Prigodin, N. V.; Epstein, A. J.; Wang, F.

    2000-10-01

    Higher dimensionality "star" polymers provide new properties beyond those found in their linear analogs. They have been used to improving electronic properties for nonlinear optics through exciton transfer and molecular antenna structures for example (M. Kawa, J. M. J. Frechet, Chem. Mater. 10, 286 (1998).). We report on photoluminescence properties of star polymers with a hyperbranched core (both hyperbranched phenlyene and hyperbranched triphenylamine) and polyhexylthiophene arms. The arm is a conjugated oligomer of polythiophene that has been investigated extensively for metallic like conductivity when doped as well as utilized in field effect transistors in its undoped form (A. Tsumara, H. Koezuka, T. Ando, Appl. Phys. Lett. 49, 1210 (1986).). The cores are respectively, a nonconjugated polymer in the case of hyperbranched phenlyene and a conjugated polymer in the case of hyperbranched triphenylamine. The photoluminesce spectrum (λ_max at 575 nm) is identical for both star polymers with the two electronically different hyperbranched cores and for linear polythiophene alone. We conclude the wave functions of the core and arms do not strongly interact to form states different from their individual states and excitons formed on the hyperbranched cores migrate to the lower bandgap polythiophene before recombining.

  18. Pairs of promoter pairs in a web of transcription.

    PubMed

    Kaplan, Craig D

    2016-08-30

    A new analysis has characterized a fundamental building block of complex transcribed loci. Constellations of core promoters can generally be reduced to pairs of divergent transcription units, where the distance between the pairs of transcription units correlates with constraints on genomic context, which in turn contribute to transcript fate. PMID:27573684

  19. Identification of modes of fracture in a 2618-T6 aluminum alloy using stereophotogrammetry

    SciTech Connect

    Salas Zamarripa, A.; Mata, M.P. Guerrero; Morales, M. Castillo; Beber-Solano, T.P.

    2011-12-15

    The identification and the development of a quantification technique of the modes of fracture in fatigue fracture surfaces of a 2618-T6 aluminum alloy were developed during this research. Fatigue tests at room and high temperature (230 Degree-Sign C) were carried out to be able to compare the microscopic fractographic features developed by this material under these testing conditions. The overall observations by scanning electron microscopy (SEM) of the fracture surfaces showed a mixture of transgranular and ductile intergranular fracture. The ductile intergranular fracture contribution appears to be more significant at room temperature than at 230 Degree-Sign C. A quantitative methodology was developed to identify and to measure the contribution of these microscopic fractographic features. The technique consisted of a combination of stereophotogrammetry and image analysis. Stereo-pairs were randomly taken along the crack paths and were then analyzed using the profile module of MeX software. The analysis involved the 3-D surface reconstruction, the trace of primary profile lines in both vertical and horizontal directions within the stereo-pair area, the measurements of the contribution of the modes of fracture in each profile, and finally, the calculation of the average contribution in each stereo-pair. The technique results confirmed a higher contribution of ductile intergranular fracture at room temperature than at 230 Degree-Sign C. Moreover, there was no indication of a direct relationship between this contribution and the strain amplitudes range applied during the fatigue testing. - Highlights: Black-Right-Pointing-Pointer Stereophotogrammetry and image analysis as a measuring tool of modes of fracture in fatigue fracture surfaces. Black-Right-Pointing-Pointer A mixture of ductile intergranular and transgranular fracture was identified at room temperature and 230 Degree-Sign C testing. Black-Right-Pointing-Pointer Development of a quantitative methodology to

  20. Urinary bromophenol glucuronide and sulfate conjugates: Potential human exposure molecular markers for polybrominated diphenyl ethers.

    PubMed

    Ho, Ka-Lok; Yau, Man-Shan; Murphy, Margaret B; Wan, Yi; Fong, Bonnie M-W; Tam, Sidney; Giesy, John P; Leung, Kelvin S-Y; Lam, Michael H-W

    2015-08-01

    One possible source of urinary bromophenol (BP) glucuronide and sulfate conjugates in mammalian animal models and humans is polybromodiphenyl ethers (PBDEs), a group of additive flame-retardants found ubiquitously in the environment. In order to study the correlation between levels of PBDEs in human blood plasma and those of the corresponding BP-conjugates in human urine, concentrations of 17 BDE congeners, 22 OH-BDE and 13 MeO-BDE metabolites, and 3 BPs in plasma collected from 100 voluntary donors in Hong Kong were measured by gas chromatograph tandem mass spectrometry (GC-MS). Geometric mean concentration of ΣPBDEs, ΣOH-BDEs, ΣMeO-BDEs and ΣBPs in human plasma were 4.45 ng g(-1) lw, 1.88 ng g(-1) lw, 0.42 ng g(-1) lw and 1.59 ng g(-1) lw respectively. Concentrations of glucuronide and sulfate conjugates of 2,4-dibromophenol (2,4-DBP) and 2,4,6-tribromophenol (2,4,6-TBP) in paired samples of urine were determined by liquid chromatography tandem triple quadrupole mass spectrometry (LC-MS/MS). BP-conjugates were found in all of the parallel urine samples, in the range of 0.08-106.49 μg g(-1)-creatinine. Correlations among plasma concentrations of ΣPBDEs/ΣOH-BDEs/ΣMeO-BDEs/ΣBPs and BP-conjugates in urine were evaluated by multivariate regression and Pearson product correlation analyses. These urinary BP-conjugates were positively correlated with ΣPBDEs in blood plasma, but were either not or negatively correlated with other organobromine compounds in blood plasma. Stronger correlations (Pearson's r as great as 0.881) were observed between concentrations of BDE congeners having the same number and pattern of bromine substitution on their phenyl rings in blood plasma and their corresponding BP-conjugates in urine. PMID:25817024

  1. Kinetic models of conjugated metabolic cycles

    NASA Astrophysics Data System (ADS)

    Ershov, Yu. A.

    2016-01-01

    A general method is developed for the quantitative kinetic analysis of conjugated metabolic cycles in the human organism. This method is used as a basis for constructing a kinetic graph and model of the conjugated citric acid and ureapoiesis cycles. The results from a kinetic analysis of the model for these cycles are given.

  2. Description of charge conjugation from first principles

    SciTech Connect

    Lujan-Peschard, C.; Napsuciale, M.

    2006-09-25

    We construct the charge conjugation operator as a unitary automorphism in the spinor space ((1/2), 0) + (0 (1/2)) from first principles. We calculate its eigenspinors and derive the equation of motion they satisfy. The mapping associated to charge conjugation is constructed from parity eigenstates which are considered as particle and antiparticle.

  3. The Conjugate Acid-Base Chart.

    ERIC Educational Resources Information Center

    Treptow, Richard S.

    1986-01-01

    Discusses the difficulties that beginning chemistry students have in understanding acid-base chemistry. Describes the use of conjugate acid-base charts in helping students visualize the conjugate relationship. Addresses chart construction, metal ions, buffers and pH titrations, and the organic functional groups and nonaqueous solvents. (TW)

  4. Novel conjugates of peptides and conjugated polymers for optoelectronics and neural interfaces

    NASA Astrophysics Data System (ADS)

    Bhagwat, Nandita

    Peptide-polymer conjugates are a novel class of hybrid materials that take advantage of each individual component giving the opportunity to generate materials with unique physical, chemical, mechanical, optical, and electronic properties. In this dissertation peptide-polymer conjugates for two different applications are discussed. The first set of peptide-polymer conjugates were developed as templates to study the intermolecular interactions between electroactive molecules by manipulating the intermolecular distances at nano-scale level. A PEGylated, alpha-helical peptide template was employed to effectively display an array of organic chromophores (oxadiazole containing phenylenevinylene oligomers, Oxa-PPV). Three Oxa-PPV chromophores were strategically positioned on each template, at distances ranging from 6 to 17 A from each other, as dictated by the chemical and structural properties of the peptide. The Oxa-PPV modified PEGylated helical peptides (produced via Heck coupling strategies) were characterized by a variety of spectroscopic methods. Electronic contributions from multiple pairs of chromophores on a scaffold were detectable; the number and relative positioning of the chromophores dictated the absorbance and emission maxima, thus confirming the utility of these polymer--peptide templates for complex presentation of organic chromophores. The rest of the thesis is focused on using poly(3,4-alkylenedioxythiophene) based conjugated polymers as coatings for neural electrodes. This thiophene derivative is of considerable current interest for functionalizing the surfaces of a wide variety of devices including implantable biomedical electronics, specifically neural bio-electrodes. Toward these ends, copolymer films of 3,4-ethylenedioxythiophene (EDOT) with a carboxylic acid functional EDOT (EDOTacid) were electrochemically deposited and characterized as a systematic function of the EDOTacid content (0, 25, 50, 75, and 100%). The chemical surface characterization

  5. Effect of PEG pairing on the efficiency of cancer-targeting liposomes.

    PubMed

    Saw, Phei Er; Park, Jinho; Lee, Eunbeol; Ahn, Sukyung; Lee, Jinju; Kim, Hyungjun; Kim, Jinjoo; Choi, Minsuk; Farokhzad, Omid C; Jon, Sangyong

    2015-01-01

    Standardized poly(ethylene glycol)-modified (PEGylated) liposomes, which have been widely used in research as well as in pre-clinical and clinical studies, are typically constructed using PEG with a molecular weight of 2000 Da (PEG(2000)). Targeting ligands are also generally conjugated using various functionalized PEG(2000)). However, although standardized protocols have routinely used PEG(2000), it is not because this molecular weight PEG has been optimized to enhance tumor uptake of nanoparticles. Herein, we investigated the effect of various PEG lipid pairings--that is, PEG lipids for targeting-ligand conjugation and PEG lipids for achieving 'stealth' function--on in vitro cancer cell- and in vivo tumor-targeting efficacy. A class of high-affinity peptides (aptides) specific to extra domain B of fibronectin (APT(EDB)) was used as a representative model for a cancer-targeting ligand. We synthesized a set of aptide-conjugated PEGylated phospholipids (APT(EDB)‑PEG(2000))‑DSPE and APT(EDB)‑PEG(2000))‑DSPE) and then paired them with methoxy-capped PEGylated phospholipids with diverse molecular weights (PEG(2000)), PEG(2000)), PEG(2000)), and PEG(2000))) to construct various aptide-conjugated PEGylated liposomes. The liposomes with APT(EDB)‑PEG(2000))/PEG(2000)) and APT(EDB)‑PEG(2000))/PEG(2000)) pairings had the highest uptake in EDB-positive cancer cells. Furthermore, in a U87MG xenograft model, APT(EDB)‑PEG(2000))/PEG(2000)) liposomes retarded tumor growth to the greatest extent, followed closely by APT(EDB)‑PEG(2000))/PEG(2000)) liposomes. Among the PEGylated liposomes tested, pairs in which the methoxy-capped PEG length was about half that of the targeting ligand-displaying PEG exhibited the best performance, suggesting that PEG pairing is a key consideration in the design of drug-delivery vehicles. PMID:25897339

  6. Experimental and Numerical Analysis of Capillary Imbibition in Fractured Sandstone under Controlled Fracture Flow Conditions

    NASA Astrophysics Data System (ADS)

    Lee, C.; Karpyn, Z. T.

    2010-12-01

    Fractures serve as primary conduits and have great impact on the migration of injected fluid into fractured permeable media. Appropriate transport properties such as relative permeability and capillary pressures are essential for successful simulation and prediction of multi-phase flow in such systems. However, the lack of thorough understanding of the dynamics governing immiscible displacement in fractured media, limit our ability to properly represent their macroscopic transport properties. The present work is one component of a multi-variable analysis of factors affecting fracture-matrix imbibition, including injection rates, fluid properties, and fracture orientation. We conduct laboratory experiments to monitor spatial and temporal evolution of saturation distributions in fractured sandstone samples. Air-brine, kerosene-brine and mixed oil-brine were used as three different fluid pairs in separate sets of experiments. Results were then mimicked using an automated history matching approach to obtain representative relative permeability and capillary pressure curves to further investigate the interplay of gravity, capillary and viscous forces, on predictive simulation tests. Sensitive analyses, in combination with direct experimental observation, allowed us to explore the relative importance of injection flow rate, gravity effect, and fluid properties on the evolving imbibition front. High fracture flow rates favor faster recovery from the matrix, at the expense of higher pore volume injected, and generate a sharp saturation transition at the edge of the imbibing front. Water saturation in the imbibed zone remains constant at around 0.5 to 0.6, suggesting a dynamic equilibrium in the mobility of the fluid phases. Liquid-liquid and gas-liquid imbibition results show significant differences in the shape of the imbibing front, breakthrough time, and saturation profiles. Results from this work also assist in the identification of favorable conditions for cocurrent

  7. Approximate error conjugation gradient minimization methods

    DOEpatents

    Kallman, Jeffrey S

    2013-05-21

    In one embodiment, a method includes selecting a subset of rays from a set of all rays to use in an error calculation for a constrained conjugate gradient minimization problem, calculating an approximate error using the subset of rays, and calculating a minimum in a conjugate gradient direction based on the approximate error. In another embodiment, a system includes a processor for executing logic, logic for selecting a subset of rays from a set of all rays to use in an error calculation for a constrained conjugate gradient minimization problem, logic for calculating an approximate error using the subset of rays, and logic for calculating a minimum in a conjugate gradient direction based on the approximate error. In other embodiments, computer program products, methods, and systems are described capable of using approximate error in constrained conjugate gradient minimization problems.

  8. Pair Programming: Issues and Challenges

    NASA Astrophysics Data System (ADS)

    Lui, Kim Man; Barnes, Kyle Atikus; Chan, Keith C. C.

    Pair programming, two programmers collaborating on design, coding and testing, has been a controversial focus of interest as Agile Software Development continues to grow in popularity both among academics and practitioners. As a result of the many investigations into the effectiveness of pair programming in the last decade, many have come to realize that there are many hard-to-control factors in pair programming in particular and in empirical software engineering in general. Because of these factors, the results of many pair programming experiments are not easy to replicate and the relative productivity of pair and solo programming are still not fully understood. So far, it has been concluded by previous studies that pair programming productivity can vary, but few have shown how and why this is the case. In this chapter, we discuss a number of challenging factors in the adoption of pair programming and present an approach to deal with them. We discuss how different factors may affect our experimental outcomes and improve experiment design to reveal how and why pair programming can be made productive, at least, in controlled situations.

  9. Assessment Strategies for Pair Programming

    ERIC Educational Resources Information Center

    Hahn, Jan Hendrik; Mentz, Elsa; Meyer, Lukas

    2009-01-01

    Although pair programming has proved its usefulness in teaching and learning programming skills, it is difficult to assess the individual roles and abilities of students whilst programming in pairs. (Note that within this manuscript, the term assessment refers to evaluating individual student performance.) Assessing only the outcomes of a pair…

  10. Supernovae in paired host galaxies

    NASA Astrophysics Data System (ADS)

    Nazaryan, T. A.; Petrosian, A. R.; Hakobyan, A. A.; Adibekyan, V. Zh.; Kunth, D.; Mamon, G. A.; Turatto, M.; Aramyan, L. S.

    2014-12-01

    We investigate the influence of close neighbor galaxies on the properties of supernovae (SNe) and their host galaxies using 56 SNe located in pairs of galaxies with different levels of star formation (SF) and nuclear activity. The mean distance of type II SNe from nuclei of hosts is greater by about a factor of 2 than that of type Ibc SNe. For the first time it is shown that SNe Ibc are located in pairs with significantly smaller difference of radial velocities between components than pairs containing SNe Ia and II. We consider this as a result of higher star formation rate (SFR) of these closer systems of galaxies. SN types are not correlated with the luminosity ratio of host and neighbor galaxies in pairs. The orientation of SNe with respect to the preferred direction toward neighbor galaxy is found to be isotropic and independent of kinematical properties of the galaxy pair.

  11. Property (RD) for Hecke Pairs

    NASA Astrophysics Data System (ADS)

    Shirbisheh, Vahid

    2012-06-01

    As the first step towards developing noncommutative geometry over Hecke C ∗-algebras, we study property (RD) (Rapid Decay) for Hecke pairs. When the subgroup H in a Hecke pair ( G, H) is finite, we show that the Hecke pair ( G, H) has (RD) if and only if G has (RD). This provides us with a family of examples of Hecke pairs with property (RD). We also adapt Paul Jolissant's works in Jolissaint (J K-Theory 2:723-735, 1989; Trans Amer Math Soc 317(1):167-196, 1990) to the setting of Hecke C ∗-algebras and show that when a Hecke pair ( G, H) has property (RD), the algebra of rapidly decreasing functions on the set of double cosets is closed under holomorphic functional calculus of the associated (reduced) Hecke C ∗-algebra. Hence they have the same K 0-groups.

  12. Base pairing and base mis-pairing in nucleic acids

    NASA Technical Reports Server (NTRS)

    Wang, A. H. J.; Rich, A.

    1986-01-01

    In recent years we have learned that DNA is conformationally active. It can exist in a number of different stable conformations including both right-handed and left-handed forms. Using single crystal X-ray diffraction analysis we are able to discover not only additional conformations of the nucleic acids but also different types of hydrogen bonded base-base interactions. Although Watson-Crick base pairings are the predominant type of interaction in double helical DNA, they are not the only types. Recently, we have been able to examine mismatching of guanine-thymine base pairs in left-handed Z-DNA at atomic resolution (1A). A minimum amount of distortion of the sugar phosphate backbone is found in the G x T pairing in which the bases are held together by two hydrogen bonds in the wobble pairing interaction. Because of the high resolution of the analysis we can visualize water molecules which fill in to accommodate the other hydrogen bonding positions in the bases which are not used in the base-base interactions. Studies on other DNA oligomers have revealed that other types of non-Watson-Crick hydrogen bonding interactions can occur. In the structure of a DNA octamer with the sequence d(GCGTACGC) complexed to an antibiotic triostin A, it was found that the two central AT base pairs are held together by Hoogsteen rather than Watson-Crick base pairs. Similarly, the G x C base pairs at the ends are also Hoogsteen rather than Watson-Crick pairing. Hoogsteen base pairs make a modified helix which is distinct from the Watson-Crick double helix.

  13. Fracture mechanics: 26. volume

    SciTech Connect

    Reuter, W.G.; Underwood, J.H.; Newman, J.C. Jr.

    1995-12-31

    The original objective of these symposia was to promote technical interchange between researchers from the US and worldwide in the field of fracture. This objective was recently expanded to promote technical interchange between researchers in the field of fatigue and fracture. The symposium began with the Swedlow Memorial Lecture entitled ``Patterns and Perspectives in Applied Fracture Mechanics.`` The remaining 42 papers are divided into the following topical sections: Constraint crack initiation; Constraint crack growth; Weldments; Engineered materials; Subcritical crack growth; Dynamic loading; and Applications. Papers within the scope of the Energy Data Base have been processed separately.

  14. Multi-size Scaling of Fluid Flow and Seismic Fracture Stiffness (Invited)

    NASA Astrophysics Data System (ADS)

    Pyrak-Nolte, L. J.; Petrovitch, C.; Nolte, D. D.

    2013-12-01

    Remote monitoring of any natural or anthropogenic process in the subsurface seeks to gain knowledge of the local fracture network geometry and the local fluid flow patterns. From the study of single fractures at laboratory scales, a clear understanding has emerged on how to interpret fracture specific stiffness from seismic data and how time-dependent processes (e.g., stress, geochemical interactions, fluid saturation) affect interpretation. However, an open challenge remains to determine if fracture specific stiffness is related to the hydraulic properties of a fracture and if this relationship holds across a broad range of scales. A finite-size scaling analysis was performed on fractures numerically simulated with weakly correlated random aperture distributions to explore whether a fundamental scaling relationship exists between fracture seismic stiffness and fracture flow behavior. Computational models were used to analyze fluid flow through a fracture undergoing deformation. The numerical methods included a stratified percolation approach to generate pore-scale fracture void geometry for fractures, a combined conjugate-gradient method and fast-multipole method for determining fracture deformation, and a flow network model for simulating fluid flow, fluid velocity and fluid pressures within a fracture. From the numerical simulations, fracture specific stiffness was determined to be a surrogate for fracture void area (traditionally used in percolation studies). Fracture specific stiffness captures the deformation of the fracture void geometry that includes both changes in contact area and aperture. This enabled a collapse of the numerical flow-stiffness data, simulated at multiple length scales, to a single scaling function. The scaling function displays two exponential regions above and below the transition into the critical regime. The transition point is governed by the multi-fractal spectrum of stress dependent flow paths. This spectrum reveals that the flow

  15. Percolation and permeability of heterogeneous fracture networks

    NASA Astrophysics Data System (ADS)

    Adler, Pierre; Mourzenko, Valeri; Thovert, Jean-François

    2013-04-01

    Natural fracture fields are almost necessarily heterogeneous with a fracture density varying with space. Two classes of variations are quite frequent. In the first one, the fracture density is decreasing from a given surface; the fracture density is usually (but not always see [1]) an exponential function of depth as it has been shown by many measurements. Another important example of such an exponential decrease consists of the Excavated Damaged Zone (EDZ) which is created by the excavation process of a gallery [2,3]. In the second one, the fracture density undergoes some local random variations around an average value. This presentation is mostly focused on the first class and numerical samples are generated with an exponentially decreasing density from a given plane surface. Their percolation status and hydraulic transmissivity can be calculated by the numerical codes which are detailed in [4]. Percolation is determined by a pseudo diffusion algorithm. Flow determination necessitates the meshing of the fracture networks and the discretisation of the Darcy equation by a finite volume technique; the resulting linear system is solved by a conjugate gradient algorithm. Only the flow properties of the EDZ along the directions which are parallel to the wall are of interest when a pressure gradient parallel to the wall is applied. The transmissivity T which relates the total flow rate per unit width Q along the wall through the whole fractured medium to the pressure gradient grad p, is defined by Q = - T grad p/mu where mu is the fluid viscosity. The percolation status and hydraulic transmissivity are systematically determined for a wide range of decay lengths and anisotropy parameters. They can be modeled by comparison with anisotropic fracture networks with a constant density. A heuristic power-law model is proposed which accurately describes the results for the percolation threshold over the whole investigated range of heterogeneity and anisotropy. Then, the data

  16. Conjugated Polymer Surfaces and Interfaces

    NASA Astrophysics Data System (ADS)

    Salaneck, W. R.; Stafstrom, S.; Brédas, J. L.

    2003-10-01

    The authors illustrate the basic physics and materials science of conjugated polymers and their interfaces, particularly, but not exclusively, as they are applied to polymer-based light emitting diodes. The approach is to describe the basic physical and associated chemical principles that apply to these materials, which in many instances are different from those that apply to their inorganic counterparts. The main aim of the authors is to highlight specific issues and properties of polymer surfaces and interfaces that are relevant in the context of the emerging field of polymer-based electronics in general, and polymer-based light emitting diodes in particular. Both theoretical and experimental methods used in the study of these systems are discussed. This book will be of interest to graduate students and research workers in departments of physics, chemistry, electrical engineering and materials sciences studying polymer surfaces and interfaces and their application in polymer-based electronics.

  17. New porphyrin glyco-conjugates

    NASA Astrophysics Data System (ADS)

    Drain, Charles M.; Singh, Sunaina; Samaroo, Diana; Thompson, Sebastian; Vinodu, Mikki; Tome, Joao P. C.

    2009-06-01

    Porphyrins bearing sugars and other motifs are proposed for a variety of therapeutic applications. Non-hydrolysable glyco conjugates of porphyrins can be formed in rapid, room temperature reacting in greater than 90% yields from tetraperfluorophenyporphyrin. Additional functional groups can be appended using the same chemistry but different stoichiometries of the reagents. Thus sugars, amines, peptides, and cationic moieties designed to target cancer cells or other diseased or disease-causing cells are made rapidly and cleanly. These compounds can then be rapidly screened for cell uptake, or selected from combinatorial libraries by cell uptake assays using a combination of fluorescence microscopy and mass spectrometry. Modifications of the macrocycle allow fine-tuning of the photonic properties for specific medical, imaging, or biochemical applications.

  18. Stereo Pair: Patagonia, Argentina

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This view of northern Patagonia, near El Cain, Argentina shows complexly eroded volcanic terrain, with basalt mesas, sinkholes, landslide debris, playas, and relatively few integrated drainage channels. Surrounding this site (but also extending far to the east) is a broad plateau capped by basalt, the Meseta de Somuncura. Here, near the western edge of the plateau, erosion has broken through the basalt cap in a variety of ways. On the mesas, water-filled sinkholes (lower left) are most likely the result of the collapse of old lava tubes. Along the edges of the mesas (several locations) the basalt seems to be sliding away from the plateau in a series of slices. Water erosion by overland flow is also evident, particularly in canyons where vegetation blankets the drainage channels (green patterns, bottom of image). However, overland water flow does not extend very far at any location. This entire site drains to local playas, some of which are seen here (blue). While the water can reach the playas and then evaporate, what becomes of the eroded rock debris? Wind might excavate some of the finer eroded debris, but the fate of much of the missing bedrock remains mysterious.

    This cross-eyed stereoscopic image pair was generated using topographic data from the Shuttle Radar Topography Mission, combined with an enhanced Landsat 7 satellite color image. The topography data are used to create two differing perspectives of a single image, one perspective for each eye. In doing so, each point in the image is shifted slightly, depending on its elevation. When stereoscopically merged, the result is a vertically exaggerated view of the Earth's surface in its full three dimensions.

    Landsat satellites have provided visible light and infrared images of the Earth continuously since 1972. SRTM topographic data match the 30-meter (99-foot) spatial resolution of most Landsat images and provide a valuable complement for studying the historic and growing Landsat data archive. The

  19. Stereo Pair, Patagonia, Argentina

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This view of northern Patagonia, at Los Menucos, Argentina shows remnants of relatively young volcanoes built upon an eroded plain of much older and contorted volcanic, granitic, and sedimentary rocks. The large purple, brown, and green 'butterfly' pattern is a single volcano that has been deeply eroded. Large holes on the volcano's flanks indicate that they may have collapsed soon after eruption, as fluid molten rock drained out from under its cooled and solidified outer shell. At the upper left, a more recent eruption occurred and produced a small volcanic cone and a long stream of lava, which flowed down a gully. At the top of the image, volcanic intrusions permeated the older rocks resulting in a chain of small dark volcanic peaks. At the top center of the image, two halves of a tan ellipse pattern are offset from each other. This feature is an old igneous intrusion that has been split by a right-lateral fault. The apparent offset is about 6.6 kilometers (4 miles). Color, tonal, and topographic discontinuities reveal the fault trace as it extends across the image to the lower left. However, young unbroken basalt flows show that the fault has not been active recently.

    This cross-eyed stereoscopic image pair was generated using topographic data from the Shuttle Radar Topography Mission, combined with an enhanced Landsat 7satellite color image. The topography data are used to create two differing perspectives of a single image, one perspective for each eye. In doing so, each point in the image is shifted slightly, depending on its elevation. When stereoscopically merged, the result is a vertically exaggerated view of the Earth's surface in its full three dimensions.

    Landsat satellites have provided visible light and infrared images of the Earth continuously since 1972. SRTM topographic data match the 30-meter (99-foot) spatial resolution of most Landsat images and provide a valuable complement for studying the historic and growing Landsat data archive

  20. Nuclear behavior in triple-conjugant fusion complexes of the ciliate Stylonychia pustulata: Inhibition of meiosis and retention of the macronucleus.

    PubMed

    Yano, J; Suhama, M

    1990-06-29

    The relationship between temporary conjugation and the conjugant fusion of the hypotrich ciliate Stylonychia pustulata was examined by use of singlet cells of stocks HH1 and TK1, and back-to-back doublet cells of stock NM2 with two attachment sites. The TK1 cells caused conjugant fusion in cell pairing. Triple-conjugant fusion (TCF) complexes composed of an HH1 cell, an NM2 doublet and a TK1 cell were obtained by mixing cells from three stocks. Multiple-conjugant fusion complexes composed of a TK1 cell and three or four NM2 doublets were also found. Initiation of meiosis in TCF complexes was not disturbed by the union of a TK1 cell and a component of the doublet member, but meiosis was blocked at the parachute stage. Thereafter, many micronuclei underwent mitosis. These results suggest that a meiosis blocking factor is present in the cytoplasm of the TK1 cell and migrates to both the doublet and the HH1 members. The macronuclei in doublet and HH1 members changed from elongated and fragmented shapes to spheres. The HH1 and doublet members shifted from conjugation to conjugant fusion. The doublet and HH1 members split from TCF complexes within an hour of the onset of pairing underwent either autogamy or cell division. PMID:23196046

  1. Tectonic Setting and Characteristics of Natural Fractures in Mesaverde and Dakota Reservoirs of the San Juan Basin, New Mexico and Colorado

    SciTech Connect

    LORENZ, JOHN C.; COOPER, SCOTT P.

    2001-01-01

    A set of vertical extension fractures, striking N-S to NNE-SSW but with local variations, is present in both the outcrop and subsurface in both Mesaverde and Dakota sandstones. Additional sets of conjugate shear fractures have been recognized in outcrops of Dakota strata and may be present in the subsurface. However, the deformation bands prevalent locally in outcrops in parts of the basin as yet have no documented subsurface equivalent. The immature Mesaverde sandstones typically contain relatively long, irregular extension fractures, whereas the quartzitic Dakota sandstones contain short, sub-parallel, closely spaced, extension fractures, and locally conjugate shear planes as well. Outcrops typically display secondary cross fractures which are rare in the subsurface, although oblique fractures associated with local structures such as the Hogback monocline may be present in similar subsurface structures. Spacings of the bed-normal extension fractures are approximately equal to or less than the thicknesses of the beds in which they formed, in both outcrop and subsurface. Fracture intensities increase in association with faults, where there is a gradation from intense fracturing into fault breccia. Bioturbation and minimal cementation locally inhibited fracture development in both formations, and the vertical limits of fracture growth are typically at bedding/lithology contrasts. Fracture mineralizations have been largely dissolved or replaced in outcrops, but local examples of preserved mineralization show that the quartz and calcite common to subsurface fractures were originally present in outcrop fractures. North-south trending compressive stresses created by southward indentation of the San Juan dome area (where Precambrian rocks are exposed at an elevation of 14,000 ft) and northward indentation of the Zuni uplift, controlled Laramide-age fracturing. Contemporaneous right-lateral transpressive wrench motion due to northeastward translation of the basin was both

  2. Fracture Angle Analysis of Rock Burst Faulting Planes Based on True-Triaxial Experiment

    NASA Astrophysics Data System (ADS)

    Gong, Weili; Peng, Yanyan; Wang, Hu; He, Manchao; Ribeiro e Sousa, L.; Wang, Jiong

    2015-05-01

    The aim of this paper is to estimate fracture angles in deep-seated rock bursts encountered in intact hard rock tunnels. The fracture angles of fault planes in rock burst failure are analytically formulated by employing stress analysis based on Mohr's circle construction. Mohr's circle construction suits well for representing the rock burst stress states including the static loading and dynamic unloading processes existing at or near the excavation surface. Four fracture angles can be precisely predicted using the proposed mathematical models, including two minimum angles for two conjugate planes where the shear stress is equal to the maximum static shear stress τ max while the normal stress approaches to zero, and two maximum angles for two conjugate planes where the normal stress is reduced from σ 1 to σ 1/2 while shear stress increases markedly from ±( σ 1- σ 3)/2 to the maximum dynamic shear τ dmax = ± σ 1/2. For validation of the analytical solutions to fracture angles, rock burst experiments on Laizhou granite were conducted using a modified true-triaxial apparatus. The predicted fracture angles are compared very well with the results obtained from the laboratory rock burst tests and are in good agreement with the in situ observations. The proposed solutions to the fracture angle are a function of the static stresses only which can be known a priori from a field survey.

  3. Mechanical Coal-Face Fracturer

    NASA Technical Reports Server (NTRS)

    Collins, E. R., Jr.

    1984-01-01

    Radial points on proposed drill bit take advantage of natural fracture planes of coal. Radial fracture points retracted during drilling and impacted by piston to fracture coal once drilling halts. Group of bits attached to array of pneumatic drivers to fracture large areas of coal face.

  4. Ordering the bestiary of genetic elements transmissible by conjugation

    PubMed Central

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

    2013-01-01

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

  5. Microwave absorption of free carriers in doped conjugated polymer films

    NASA Astrophysics Data System (ADS)

    Rumbles, Garry

    Flash photolysis time-resolved microwave conductivity (fp-TRMC) is a powerful spectroscopic tool for the detection of mobile charges in organic systems, such as conjugated polymers. We will report on a study of charge carrier generation in a number of polymer systems where the solid-state microstructure (SSM) of the thin films can be controlled using both molecular structure and processing conditions. By incorporating a low concentration of molecular acceptors, such as metallo-phthalocyanines, as well as substituted fullerenes and perylenes, the driving force for photoinduced electron transfer can be controlled through the excited state energy and the reduction potential. Our results indicate the importance of the crystalline phase of the polymer to stabilise and reduce the rate of recombination of the holes with the electrons that remain trapped on the acceptor. In addition, the role that the SSM plays on the stabilization of bound electron-hole pairs, or charge-transfer (CT) states will be examined.

  6. Noise-Immune Conjugate Large-Area Atom Interferometers

    SciTech Connect

    Chiow Shengwey; Herrmann, Sven; Chu, Steven; Mueller, Holger

    2009-07-31

    We present a pair of simultaneous conjugate Ramsey-Borde atom interferometers using large (20(Planck constant/2pi)k)-momentum transfer beam splitters, where (Planck constant/2pi)k is the photon momentum. Simultaneous operation allows for common-mode rejection of vibrational noise. This allows us to surpass the enclosed space-time area of previous interferometers with a splitting of 20(Planck constant/2pi)k by a factor of 2500. Using a splitting of 10(Planck constant/2pi)k, we demonstrate a 3.4 ppb resolution in the measurement of the fine structure constant. Examples for applications in tests of fundamental laws of physics are given.

  7. Clavicle Fracture (Broken Collarbone)

    MedlinePlus

    ... place and the fragments are severely out of alignment. A large bump over the fracture site may ... bone fragments are first repositioned into their normal alignment, and then held in place with special screws ...

  8. Sprains, Strains and Fractures

    MedlinePlus

    ... are useful for finding soft issue injuries (including torn ligaments) and stress fractures. Treatment will depend on ... weeks. Professional athletes may undergo surgery to repair torn ligaments. Oral anti-inflammatory medication, such as ibuprofen, ...

  9. Lisfranc (Midfoot) Fractures

    MedlinePlus

    ... broken or ligaments that support the midfoot are torn. The severity of the injury can vary from ... bones are broken (fractured) or the ligaments are torn (ruptured). Injuries can vary, from a simple injury ...

  10. Femur fracture repair - discharge

    MedlinePlus

    ... McCormack RG, Lopez CA. Commonly encountered fractures in sports medicine. In: Miller MD, Thompson SR, eds. DeLee and Drez's Orthopaedic Sports Medicine. 4th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap ...

  11. Metatarsal stress fractures - aftercare

    MedlinePlus

    ... McCormack RG, Lopez CA. Commonly encountered fractures in sports medicine. In: Miller MD, Thompson SR, eds. DeLee and Drez's Orthopaedic Sports Medicine . 4th ed. Philadelphia, PA: Saunders Elsevier; 2014:chap. ...

  12. Fractures in medieval Scotland.

    PubMed

    MacLennan, W J

    2001-04-01

    The prevalence of fractures in medieval Scotland is assessed, particular attention being given to excavations of cemeteries beside three Carmelite cemeteries, at Aberdeen, Perth and Linlithgow, and another one at Whithorn Abbey. In the friaries the prevalence of fractures was 7.6% and in Whithorn it was 5.0%. These figures are comparable with an estimated prevalence of 7.2% for individuals between 0 and 65 years in present day Scotland. Males were more at risk of fractures than females, but a small group from both genders had been struck on the head by weapons. A study from a rural cemetery in England indicates that both male and female peasants had a much higher risk of fractures than their urban counterparts. PMID:11394343

  13. Suspensions in hydraulic fracturing

    SciTech Connect

    Shah, S.N.

    1996-12-31

    Suspensions or slurries are widely used in well stimulation and hydraulic fracturing processes to enhance the production of oil and gas from the underground hydrocarbon-bearing formation. The success of these processes depends significantly upon having a thorough understanding of the behavior of suspensions used. Therefore, the characterization of suspensions under realistic conditions, for their rheological and hydraulic properties, is very important. This chapter deals with the state-of-the-art hydraulic fracturing suspension technology. Specifically it deals with various types of suspensions used in well stimulation and fracturing processes, their rheological characterization and hydraulic properties, behavior of suspensions in horizontal wells, review of proppant settling velocity and proppant transport in the fracture, and presently available measurement techniques for suspensions and their merits. Future industry needs for better understanding of the complex behavior of suspensions are also addressed. 74 refs., 21 figs., 1 tab.

  14. Ankle fracture - aftercare

    MedlinePlus

    ... page: //medlineplus.gov/ency/patientinstructions/000548.htm Ankle fracture - aftercare To use the sharing features on this ... Sit with your foot elevated higher than your knee at least 4 times a day Apply an ...

  15. Ion Pair-π Interactions.

    PubMed

    Fujisawa, Kaori; Humbert-Droz, Marie; Letrun, Romain; Vauthey, Eric; Wesolowski, Tomasz A; Sakai, Naomi; Matile, Stefan

    2015-09-01

    We report that anion-π and cation-π interactions can occur on the same aromatic surface. Interactions of this type are referred to as ion pair-π interactions. Their existence, nature, and significance are elaborated in the context of spectral tuning, ion binding in solution, and activation of cell-penetrating peptides. The origin of spectral tuning by ion pair-π interactions is unraveled with energy-minimized excited-state structures: The solvent- and pH-independent red shift of absorption and emission of push-pull fluorophores originates from antiparallel ion pair-π attraction to their polarized excited state. In contrast, the complementary parallel ion pair-π repulsion is spectroscopically irrelevant, in part because of charge neutralization by intriguing proton and electron transfers on excited push-pull surfaces. With time-resolved fluorescence measurements, very important differences between antiparallel and parallel ion pair-π interactions are identified and quantitatively dissected from interference by aggregation and ion pair dissociation. Contributions from hydrogen bonding, proton transfer, π-π interactions, chromophore twisting, ion pairing, and self-assembly are systematically addressed and eliminated by concise structural modifications. Ion-exchange studies in solution, activation of cell-penetrating peptides in vesicles, and computational analysis all imply that the situation in the ground state is complementary to spectral tuning in the excited state; i.e., parallel rather than antiparallel ion pair-π interactions are preferred, despite repulsion from the push-pull dipole. The overall quite complete picture of ion pair-π interactions provided by these remarkably coherent yet complex results is expected to attract attention throughout the multiple disciplines of chemistry involved. PMID:26291550

  16. Dynamic fracture toughness

    NASA Technical Reports Server (NTRS)

    Kobayashi, A. S.; Ramulu, M.; Dadkhah, M. S.; Yang, K.-H.; Kang, B. S. J.

    1986-01-01

    Dynamic fracture toughness versus crack velocity relations of Homalite-100, polycarbonate, hardened 4340 steel and reaction bonded silicon nitride are reviewed and discrepancies with published data and their probable causes are discussed. Data scatter in published data are attributed in part to the observed fluctuations in crack velocities. The results reaffirmed our previous conclusion that the dynamic fracture toughness versus crack velocity relation is specimen dependent and that the dynamic arrest stress intensity factor is not a unique material property.

  17. Relative permeability through fractures

    SciTech Connect

    Diomampo, Gracel, P.

    2001-08-01

    The mechanism of two-phase flow through fractures is of importance in understanding many geologic processes. Currently, two-phase flow through fractures is still poorly understood. In this study, nitrogen-water experiments were done on both smooth and rough parallel plates to determine the governing flow mechanism for fractures and the appropriate methodology for data analysis. The experiments were done using a glass plate to allow visualization of flow. Digital video recording allowed instantaneous measurement of pressure, flow rate and saturation. Saturation was computed using image analysis techniques. The experiments showed that gas and liquid phases flow through fractures in nonuniform separate channels. The localized channels change with time as each phase path undergoes continues breaking and reforming due to invasion of the other phase. The stability of the phase paths is dependent on liquid and gas flow rate ratio. This mechanism holds true for over a range of saturation for both smooth and rough fractures. In imbibition for rough-walled fractures, another mechanism similar to wave-like flow in pipes was also observed. The data from the experiments were analyzed using Darcy's law and using the concept of friction factor and equivalent Reynold's number for two-phase flow. For both smooth- and rough-walled fractures a clear relationship between relative permeability and saturation was seen. The calculated relative permeability curves follow Corey-type behavior and can be modeled using Honarpour expressions. The sum of the relative permeabilities is not equal one, indicating phase interference. The equivalent homogeneous single-phase approach did not give satisfactory representation of flow through fractures. The graphs of experimentally derived friction factor with the modified Reynolds number do not reveal a distinctive linear relationship.

  18. Influence of conjugation and other structural changes on the activity of Cu²⁺ based PNAzymes.

    PubMed

    Ghidini, A; Murtola, M; Strömberg, R

    2016-03-01

    We have previously shown that PNA-neocuproine conjugates can act as artificial RNA restriction enzymes. In the present study we have additionally conjugated the PNA with different entities, such as oligoethers, peptides etc. and also constructed systems where the PNA is designed to clamp the target RNA forming a triplex. Some conjugations are detrimental for the activity while most are silent which means that conjugation can be done to alter physical properties without losing activity. Conjugation with a single oligoether close to the neocuproine does enhance the rate almost twofold compared to the system without the oligoether. The systems designed to clamp the RNA target by forming a triplex retain the activity if the added oligoT sequence is 5 PNA units or shorter and extends the arsenal of artificial RNA restriction enzymes. Changing the direction of a closing base pair, where the target RNA forms a bulge, from a GC to a CG pair enhances the rate of cleavage somewhat without compromising the selectivity, leading to the so far most efficient artificial nuclease reported. PMID:26856621

  19. Conjugate Acid-Base Pairs, Free Energy, and the Equilibrium Constant

    ERIC Educational Resources Information Center

    Beach, Darrell H.

    1969-01-01

    Describes a method of calculating the equilibrium constant from free energy data. Values of the equilibrium constants of six Bronsted-Lowry reactions calculated by the author's method and by a conventional textbook method are compared. (LC)

  20. Pairing Correlations at High Spins

    NASA Astrophysics Data System (ADS)

    Ma, Hai-Liang; Dong, Bao-Guo; Zhang, Yan; Fan, Ping; Yuan, Da-Qing; Zhu, Shen-Yun; Zhang, Huan-Qiao; Petrache, C. M.; Ragnarsson, I.; Carlsson, B. G.

    The pairing correcting energies at high spins in 161Lu and 138Nd are studied by comparing the results of the cranked-Nilsson-Strutinsky (CNS) and cranked-Nilsson-Strutinsky-Bogoliubov (CNSB) models. It is concluded that the Coriolis effect rather than the rotational alignment effect plays a major role in the reduction of the pairing correlations in the high spin region. Then we proposed an average pairing correction method which not only better reproduces the experimental data comparing with the CNS model but also enables a clean-cut tracing of the configurations thus the full-spin-range discussion on the various rotating bands.

  1. Pairing Properties of Superheavy Nuclei

    SciTech Connect

    Staszczak, A.; Dobaczewski, J.; Nazarewicz, Witold

    2007-01-01

    Pairing properties of even-even superheavy N=184 isotones are studied within the Skyrme-Hartree-Fock+BCS approach. In the particle-hole channel we take the Skyrme energy density functional SLy4, while in the particle-particle channel we employ the seniority pairing force and zero-range delta-interactions with different forms of density dependence. We conclude that the calculated static fission trajectories weakly depend on the specific form of the delta-pairing interaction. We also investigate the impact of triaxiality on the inner fission barrier and find a rather strong Z dependence of the effect.

  2. Hybrid fracture and the transition from extension fracture to shear fracture.

    PubMed

    Ramsey, Jonathan M; Chester, Frederick M

    2004-03-01

    Fracture is a fundamental mechanism of material failure. Two basic types of brittle fractures are commonly observed in rock deformation experiments--extension (opening mode) fractures and shear fractures. For nearly half a century it has been hypothesized that extension and shear fractures represent end-members of a continuous spectrum of brittle fracture types. However, observations of transitional fractures that display both opening and shear modes (hybrids) in naturally deformed rock have often remained ambiguous, and a clear demonstration of hybrid fracture formation has not been provided by experiments. Here we present the results of triaxial extension experiments on Carrara marble that show a continuous transition from extension fracture to shear fracture with an increase in compressive stress. Hybrid fractures form under mixed tensile and compressive stress states at acute angles to the maximum principal compressive stress. Fracture angles are greater than those observed for extension fractures and less than those observed for shear fractures. Fracture surfaces also display a progressive change from an extension to shear fracture morphology. PMID:14999279

  3. FRACTURING FLUID CHARACTERIZATION FACILITY

    SciTech Connect

    Subhash Shah

    2000-08-01

    Hydraulic fracturing technology has been successfully applied for well stimulation of low and high permeability reservoirs for numerous years. Treatment optimization and improved economics have always been the key to the success and it is more so when the reservoirs under consideration are marginal. Fluids are widely used for the stimulation of wells. The Fracturing Fluid Characterization Facility (FFCF) has been established to provide the accurate prediction of the behavior of complex fracturing fluids under downhole conditions. The primary focus of the facility is to provide valuable insight into the various mechanisms that govern the flow of fracturing fluids and slurries through hydraulically created fractures. During the time between September 30, 1992, and March 31, 2000, the research efforts were devoted to the areas of fluid rheology, proppant transport, proppant flowback, dynamic fluid loss, perforation pressure losses, and frictional pressure losses. In this regard, a unique above-the-ground fracture simulator was designed and constructed at the FFCF, labeled ''The High Pressure Simulator'' (HPS). The FFCF is now available to industry for characterizing and understanding the behavior of complex fluid systems. To better reflect and encompass the broad spectrum of the petroleum industry, the FFCF now operates under a new name of ''The Well Construction Technology Center'' (WCTC). This report documents the summary of the activities performed during 1992-2000 at the FFCF.

  4. Treatment of Thoracolumbar Fracture

    PubMed Central

    Kim, Byung-Guk; Shin, Dong-Eun

    2015-01-01

    The most common fractures of the spine are associated with the thoracolumbar junction. The goals of treatment of thoracolumbar fracture are leading to early mobilization and rehabilitation by restoring mechanical stability of fracture and inducing neurologic recovery, thereby enabling patients to return to the workplace. However, it is still debatable about the treatment methods. Neurologic injury should be identified by thorough physical examination for motor and sensory nerve system in order to determine the appropriate treatment. The mechanical stability of fracture also should be evaluated by plain radiographs and computed tomography. In some cases, magnetic resonance imaging is required to evaluate soft tissue injury involving neurologic structure or posterior ligament complex. Based on these physical examinations and imaging studies, fracture stability is evaluated and it is determined whether to use the conservative or operative treatment. The development of instruments have led to more interests on the operative treatment which saves mobile segments without fusion and on instrumentation through minimal invasive approach in recent years. It is still controversial for the use of these treatments because there have not been verified evidences yet. However, the morbidity of patients can be decreased and good clinical and radiologic outcomes can be achieved if the recent operative treatments are used carefully considering the fracture pattern and the injury severity. PMID:25705347

  5. Which displaced spiral tibial shaft fractures can be managed conservatively?

    PubMed

    Toivanen, J A; Kyrö, A; Heiskanen, T; Koivisto, A M; Mattila, P; Järvinen, M J

    2000-01-01

    The aim of the present study was to establish a threshold for the initial displacement of a spiral tibial shaft fracture beyond which its retention in an acceptable position cannot be guaranteed by plaster immobilization. We reviewed the records and radiographs of 131 plaster cast-treated patients with spiral tibial shaft fracture, initially displaced 50% or less, for patients whose fracture had either lost its acceptable retention or consolidated in an unacceptable position. The fractures were classified, according to the true initial displacement as measured on the first radiographs, into four pairs of categories using cut-off points of 10, 20, 30 and 40% of the diameter of the tibial diaphysis. Comparison was then made of the proportions of failed treatments between each of these pairs. Plaster cast treatments failed in 28% when the true initial displacement was 30% or less, and in 46% when the true initial displacement was more than 30%. The risk of failed plaster cast treatment increased when true initial displacement exceeded 30%. In all patients whose plaster cast treatment was interrupted the true initial displacement was more than 30%. We therefore conclude that diaphyseal fractures of the tibia for which the initial displacement exceeds 30% are not suitable for plaster cast treatment. PMID:10990386

  6. Ultraviolet phase conjugation and its practical implications

    SciTech Connect

    Shapiro, S.L.; Fisher, R.A.; Feldman, B.J.

    1981-01-01

    We report the first demonstration of uv phase conjugation. Using a 15 psec, 2660 A pulse, 0.1% conjugate reflectivities were obtained via degenerate four-wave mixing in 1-mm samples of CS/sub 2/ mixtures. While pure CS/sub 2/ did not exhibit the effect, dilution in several uv transmitting solvents opened up a concentration-tunable (2450 A - 2850 A) spectral window, allowing the optical Kerr effect to be utilized. Weaker phase conjugation at 2660 A was also observed in other Kerr media and in saturable absorber media.

  7. Ultraviolet phase conjugation and its practical implications

    SciTech Connect

    Feldman, B.J.; Fisher, R.A.; Shapiro, S.L.

    1980-01-01

    The first demonstration of uv phase conjugation is reported. Using a 15 psec, 2660 A pulse, 0.1% conjugate reflectivities were obtained via degenerate four-wave mixing in 1-mm samples of CS/sub 2/ mixtures. While pure CS/sub 2/ did not exhibit the effect, dilution in several uv transmitting solvents opened up a concentration-tunable (2450 A to 2850 A) spectral window, allowing the optical Kerr effect to be utilized. Weaker phase conjugation at 2660 A was also observed in other Kerr media and in saturable absorber media.

  8. Xenobiotic conjugation with phosphate - a metabolic rarity.

    PubMed

    Mitchell, Stephen C

    2016-08-01

    1. Although not unknown, the conjugation of a xenobiotic with phosphate appears a rarity amongst the routes available for foreign compound metabolism. This is especially true in mammals and may be somewhat surprising as conjugation with sulphate, a seemingly similar moiety, is commonplace. 2. Information from the literature, where xenobiotic phosphate conjugates have been described or suggested, has been collated and presented in this article. By bringing together this diverse material, hopefully interest will be generated in this unusual xenobiotic reaction, and perhaps further research undertaken to better understand and delineate the reasons for its relative absence from the xenobiotic scene. PMID:26611118

  9. [The ECMES [Centro-Medullary Elastic Stabilising Wiring) osteosynthesis method in limb fractures in children. Principle, application on the femur. Apropos of 250 fractures followed-up since 1979].

    PubMed

    Prévot, J; Lascombes, P; Ligier, J N

    The theoretical basis of this new technique were recalled: a closed operation respecting the conjugation cartilages. The material, composed of flexible wires of adequate diameter are bent and stabilised forming a non traumatic fixation which is inserted into the medullary canal of the fractured bone under fluoroscopic surveillance. The second part of this paper deals with the results of 250 fractures of the femur followed up since 1979. Late outcome in terms of complications and stimulation of the post-trauma growth, which is a problem in all forms of fractures in the child, especially of the femur, is presented. PMID:7729190

  10. Pairing in hot rotating nuclei

    SciTech Connect

    Hung, N. Quang; Dang, N. Dinh

    2008-12-15

    Nuclear pairing properties are studied within an approach that includes the quasiparticle-number fluctuation (QNF) and coupling to the quasiparticle-pair vibrations at finite temperature and angular momentum. The formalism is developed to describe noncollective rotations about the symmetry axis. The numerical calculations are performed within a doubly folded equidistant multilevel model as well as several realistic nuclei. The results obtained for the pairing gap, total energy, and heat capacity show that the QNF smoothes out the sharp SN phase transition and leads to the appearance of a thermally assisted pairing gap in rotating nuclei at finite temperature. The corrections due to the dynamic coupling to SCQRPA vibrations and particle-number projection are analyzed. The effect of backbending of the momentum of inertia as a function of squared angular velocity is also discussed.

  11. Dynamical interactions of galaxy pairs

    NASA Technical Reports Server (NTRS)

    Athanassoula, E.

    1990-01-01

    Here the author briefly reviews the dynamics of sinking satellites and the effect of companions on elliptical galaxies. The author then discusses recent work on interacting disk systems, and finally focuses on a favorite interacting pair, NGC 5194/5195.

  12. Motion detection, novelty filtering, and target tracking using an interferometric technique with a GaAs phase conjugate mirror

    NASA Technical Reports Server (NTRS)

    Cheng, Li-Jen (Inventor); Liu, Tsuen-Hsi (Inventor)

    1990-01-01

    A method and apparatus is disclosed for detecting and tracking moving objects in a noise environment cluttered with fast-and slow-moving objects and other time-varying background. A pair of phase conjugate light beams carrying the same spatial information commonly cancel each other out through an image subtraction process in a phase conjugate interferometer, wherein gratings are formed in a fast photo-refractive phase conjugate mirror material. In the steady state, there is no output. When the optical path of one of the two phase conjugate beams is suddenly changed, the return beam loses its phase conjugate nature and the inter-ferometer is out of balance, resulting in an observable output. The observable output lasts until the phase conjugate nature of the beam has recovered. The observable time of the output signal is roughly equal to the formation time of the grating. If the optical path changing time is slower than the formation time, the change of optical path becomes unobservable, because the index grating can follow the change. Thus, objects traveling at speeds which result in a path changing time which is slower than the formation time are not observable and do not clutter the output image view.

  13. Motion detection, novelty filtering, and target tracking using an interferometric technique with GaAs phase conjugate mirror

    NASA Technical Reports Server (NTRS)

    Cheng, Li-Jen (Inventor); Liu, Tsuen-Hsi (Inventor)

    1991-01-01

    A method and apparatus for detecting and tracking moving objects in a noise environment cluttered with fast- and slow-moving objects and other time-varying background. A pair of phase conjugate light beams carrying the same spatial information commonly cancel each other out through an image subtraction process in a phase conjugate interferometer, wherein gratings are formed in a fast photorefractive phase conjugate mirror material. In the steady state, there is no output. When the optical path of one of the two phase conjugate beams is suddenly changed, the return beam loses its phase conjugate nature and the interferometer is out of balance, resulting in an observable output. The observable output lasts until the phase conjugate nature of the beam has recovered. The observable time of the output signal is roughly equal to the formation time of the grating. If the optical path changing time is slower than the formation time, the change of optical path becomes unobservable, because the index grating can follow the change. Thus, objects traveling at speeds which result in a path changing time which is slower than the formation time are not observable and do not clutter the output image view.

  14. SUPERPOSE-An excel visual basic program for fracture modeling based on the stress superposition method

    NASA Astrophysics Data System (ADS)

    Ismail Ozkaya, Sait

    2014-03-01

    An Excel Visual Basic program, SUPERPOSE, is presented to predict the distribution, relative size and strike of tensile and shear fractures on anticlinal structures. The program is based on the concept of stress superposition; addition of curvature-related local tensile stress and regional far-field stress. The method accurately predicts fractures on many Middle East Oil Fields that were formed under a strike slip regime as duplexes, flower structures or inverted structures. The program operates on the Excel platform. The program reads the parameters and structural grid data from an Excel template and writes the results to the same template. The program has two routines to import structural grid data in the Eclipse and Zmap formats. The platform of SUPERPOSE is a single layer structural grid of a given cell size (e.g. 50×50 m). In the final output, a single tensile or two conjugate shear fractures are placed in each cell if fracturing criteria are satisfied; otherwise the cell is left blank. Strike of the representative fracture(s) is calculated and exact, but the length is an index of fracture porosity (fracture density×length×aperture) within that cell.

  15. Mitochondria-specific Conjugated Polymer Nanoparticles

    PubMed Central

    Twomey, Megan; Mendez, Eladio; Manian, Rajesh Kumar

    2016-01-01

    Biodegradable conjugated polymer nanoparticles (CPNs) were prepared for high mitochondria targeting in live cancer cells. The degradable CPNs are nontoxic and specifically localized to mitochondria of live tumor cells through macropinocytosis followed by intracellular degradation and trafficking. PMID:26974193

  16. Design and Application of Antimicrobial Peptide Conjugates.

    PubMed

    Reinhardt, Andre; Neundorf, Ines

    2016-01-01

    Antimicrobial peptides (AMPs) are an interesting class of antibiotics characterized by their unique antibiotic activity and lower propensity for developing resistance compared to common antibiotics. They belong to the class of membrane-active peptides and usually act selectively against bacteria, fungi and protozoans. AMPs, but also peptide conjugates containing AMPs, have come more and more into the focus of research during the last few years. Within this article, recent work on AMP conjugates is reviewed. Different aspects will be highlighted as a combination of AMPs with antibiotics or organometallic compounds aiming to increase antibacterial activity or target selectivity, conjugation with photosensitizers for improving photodynamic therapy (PDT) or the attachment to particles, to name only a few. Owing to the enormous resonance of antimicrobial conjugates in the literature so far, this research topic seems to be very attractive to different scientific fields, like medicine, biology, biochemistry or chemistry. PMID:27187357

  17. Design and Application of Antimicrobial Peptide Conjugates

    PubMed Central

    Reinhardt, Andre; Neundorf, Ines

    2016-01-01

    Antimicrobial peptides (AMPs) are an interesting class of antibiotics characterized by their unique antibiotic activity and lower propensity for developing resistance compared to common antibiotics. They belong to the class of membrane-active peptides and usually act selectively against bacteria, fungi and protozoans. AMPs, but also peptide conjugates containing AMPs, have come more and more into the focus of research during the last few years. Within this article, recent work on AMP conjugates is reviewed. Different aspects will be highlighted as a combination of AMPs with antibiotics or organometallic compounds aiming to increase antibacterial activity or target selectivity, conjugation with photosensitizers for improving photodynamic therapy (PDT) or the attachment to particles, to name only a few. Owing to the enormous resonance of antimicrobial conjugates in the literature so far, this research topic seems to be very attractive to different scientific fields, like medicine, biology, biochemistry or chemistry. PMID:27187357

  18. Atomic phase conjugation from a Bose condensate

    SciTech Connect

    Goldstein, E.V.; Plaettner, K.; Meystre, P.

    1996-08-01

    The authors discuss the possibility of observing atomic phase conjugation from Bose condensates, and using it as a diagnostic tool to access the spatial coherence properties and to measure the lifetime of the condensate. They argue that since phase conjugation results from the scattering of a partial matter wave off the spatial grating produced by two other waves, it offers a natural way to directly measure such properties, and as such provides an attractive alternative to the optical methods proposed in the past.

  19. Periodic amplification and conjugation of optical solitons.

    PubMed

    Goedde, C G; Kath, W L; Kumar, P

    1995-06-15

    Nondegenerate optical parametric amplifiers can be used to simultaneously phase conjugate and amplify a pulse in a nonlinear optical fiber. The gain in the amplifiers compensates the linear loss in the fiber, while the phase conjugation effectively neutralizes second-order dispersion, self-phase modulation, the Raman self-frequency shift, and Gordon-Haus jitter. If the remaining third-order and nonlinear dispersions balance, solitonlike pulses are able to propagate with subpicosecond pulse widths. PMID:19862016

  20. Proton-neutron pairing and alpha-type condensation in nuclei

    SciTech Connect

    Sandulescu, N.; Negrea, D.; Gambacurta, D.

    2015-10-15

    We summarize a recent work (N. Sandulescu et al, arXiv:1507.04144) on isoscalar and isovector proton-neutron pairing treated in a formalism which conserves exactly the particle number and the isospin. The formalism is designed for self-conjugate (N=Z) systems of nucleons moving in an axially deformed mean field and interacting through the most general isovector and isoscalar pairing interactions. The ground state of these systems is described by a superposition of two types of condensates, i.e., condensates of isovector quartets, built by two isovector pairs coupled to the total isospin T=0, and condensates of isoscalar proton-neutron pairs. The comparison with the exact solutions of realistic isovector-isoscalar pairing Hamiltonians shows that this formalism is able to describe accurately the pairing correlations energies. It is also shown that, contrary to the majority of HFB calculations, in the present formalism the isovector and isoscalar pairing correlations coexist together for any pairing interactions.

  1. Fracture behavior across interfaces

    NASA Astrophysics Data System (ADS)

    Petrie, E. S.; Evans, J. P.; Jeppson, T. N.

    2011-12-01

    Faults and fracture networks at depth are important fluid pathways, especially in fine-grained, low permeability seal lithologies. Discontinues in sealing lithologies can create seal bypass systems, leading to the failure of CO2 geosequestration sites or hydrocarbon traps. We characterize the occurrence of and changes in discontinuity patterns and the associated changes in elastic moduli across sedimentologic interfaces to document the importance of these discontinuities for fluid management in the subsurface and potential for re-activation in high-pressure injection scenarios. We evaluate well-exposed, fine-grained, low-permeability Mesozoic and Paleozoic units that are seals of potential CO2 repositories on the Colorado Plateau and show evidence for open fractures and fluid flow in the subsurface. Field observations document changes in fracture distributions across lithologic boundaries allowing us to identify mechano-stratigraphic units and focus on the effect of lithologic interfaces on fracture distribution. An interface marks the boundary between facies in a seal and in this study the fractures are shown to deflect or arrest at the interface. In outcrop fracture intensity varies in from 1 to 18 fractures per meter and fracture apertures range from mm to cm. The mineralized fractures often have associated alteration halos along their boundaries; their general orientation follows that of discontinuities within the underlying reservoir facies or adjacent faults. The recognition of these changes in fracture distribution is important for forward modeling of fluid flow and risk management. Studying the occurrence of and changes in fracture patterns from outcrops and scaling it up for use in modeling at a field scale is difficult due to the lack of direct correlation between outcrop observations and subsurface data. Due to the size and amount of data needed to model fluid flow at the field scale the meso-scale (cm to m) variability of rock properties is often

  2. A New Physics-Based Modeling of Multiple Non-Planar Hydraulic Fractures Propagation

    SciTech Connect

    Zhou, Jing; Huang, Hai; Deo, Milind; Jiang, Shu

    2015-10-01

    Because of the low permeability in shale plays, closely spaced hydraulic fractures and multilateral horizontal wells are generally required to improve production. Therefore, understanding the potential fracture interaction and stress evolution is critical in optimizing fracture/well design and completion strategy in multi-stage horizontal wells. In this paper, a novel fully coupled reservoir flow and geomechanics model based on the dual-lattice system is developed to simulate multiple non-planar fractures propagation. The numerical model from Discrete Element Method (DEM) is used to simulate the mechanics of fracture propagations and interactions, while a conjugate irregular lattice network is generated to represent fluid flow in both fractures and formation. The fluid flow in the formation is controlled by Darcy’s law, but within fractures it is simulated by using cubic law for laminar flow through parallel plates. Initiation, growth and coalescence of the microcracks will lead to the generation of macroscopic fractures, which is explicitly mimicked by failure and removal of bonds between particles from the discrete element network. We investigate the fracture propagation path in both homogeneous and heterogeneous reservoirs using the simulator developed. Stress shadow caused by the transverse fracture will change the orientation of principal stress in the fracture neighborhood, which may inhibit or alter the growth direction of nearby fracture clusters. However, the initial in-situ stress anisotropy often helps overcome this phenomenon. Under large in-situ stress anisotropy, the hydraulic fractures are more likely to propagate in a direction that is perpendicular to the minimum horizontal stress. Under small in-situ stress anisotropy, there is a greater chance for fractures from nearby clusters to merge with each other. Then, we examine the differences in fracture geometry caused by fracturing in cemented or uncemented wellbore. Moreover, the impact of

  3. Computed tomography of facial fractures.

    PubMed

    Furlow, Bryant

    2014-01-01

    Facial skeletal fractures are common, potentially serious, and frequently associated with other life-threatening conditions, such as traumatic brain injuries. Facial fractures can be simple or complex and sometimes involve serious complications. Computed tomography has revolutionized the rapid and precise assessment of craniofacial and neck fractures in patients with severe facial trauma. This article introduces readers to the epidemiology, skeletal anatomy and biomechanics, complications, and diagnostic imaging of facial fractures. In addition, this article describes efforts to develop and validate a quantitative scoring system for facial fracture severity and reviews treatment strategies for facial skeletal fractures. PMID:24806070

  4. Fracture-Flow-Enhanced Solute Diffusion into Fractured Rock

    SciTech Connect

    Wu, Yu-Shu; Ye, Ming; Sudicky, E.A.

    2007-12-15

    We propose a new conceptual model of fracture-flow-enhanced matrix diffusion, which correlates with fracture-flow velocity, i.e., matrix diffusion enhancement induced by rapid fluid flow within fractures. According to the boundary-layer or film theory, fracture flow enhanced matrix diffusion may dominate mass-transfer processes at fracture-matrix interfaces, because rapid flow along fractures results in large velocity and concentration gradients at and near fracture-matrix interfaces, enhancing matrix diffusion at matrix surfaces. In this paper, we present a new formulation of the conceptual model for enhanced fracture-matrix diffusion, and its implementation is discussed using existing analytical solutions and numerical models. In addition, we use the enhanced matrix diffusion concept to analyze laboratory experimental results from nonreactive and reactive tracer breakthrough tests, in an effort to validate the new conceptual model.

  5. Asymmetry and polarity of the South Atlantic conjugated margins related to the presence of cratons: a numerical study

    NASA Astrophysics Data System (ADS)

    Andrés-Martínez, Miguel; Pérez-Gussinyé, Marta; de Monserrat Navarro, Albert; Morgan, Jason P.

    2015-04-01

    Tectonic asymmetry of conjugated passive margins, where one margin is much narrower than the conjugate one, is commonly observed at many passive margins world-wide. Conjugate margin asymmetry has been suggested to be a consequence of lateral changes in rheology, composition, temperature gradient or geometries of the crust and lithosphere. Here we use the South Atlantic margins (from Camamu/Gabon to North Santos/South Kwanza) as a natural laboratory to understand conjugate margin asymmetry. Along this margin sector the polarity of the asymmetry changes. To the North, the Brazilian margin developed in the strong Sao Francisco craton, and this constitutes the narrow side of the conjugate pair. To the South, the Brazilian margin developed in the Ribeira fold belt, and the margin is wide. The opposite is true for the African side. We have thus numerically analysed how the relative distance between the initial location of extension and the craton influences the symmetry/asymmetry and polarity of the conjugate margin system. Our numerical model is 2D visco-elasto-plastic and has a free surface, strain weakening and shear heating. The initial set-up includes a cratonic domain, a mobile belt and a transition area between both. We have run tests with different rheologies, thickness of the lithosphere, and weak seeds at different distances from the craton. Results show asymmetric conjugated margins, where the narrower margin is generally the closest to the craton. Our models also allow us to study how the polarity is controlled by the distance between the initial weakness and the craton, and help to understand how the presence of cratonic domains affects the final architecture of the conjugated margins.

  6. Mass of Galaxies in Pairs

    NASA Astrophysics Data System (ADS)

    Junqueira, S.; Chan, R.

    We have compared the frequency distribution of the dynamical observed quantity log (V r), for a sample of 46 pairs of elliptical galaxies, to the distribution of this quantity obtained from numerical simulations of pairs of galaxies. From such an analysis, where we have considered the structure of the galaxies and its influence in the orbital evolution of the system, we have obtained the characteristic mass and the mass-luminosity ratio for the sample. Our results show that the hypothesis of point-mass in elliptical orbits is, for this sample, an approximation as good as the model that takes into account the structure of the galaxies. The statistical method used here gives an estimate of a more reliable mass, it minimizes the contamination of spurious pairs and it considers adequately the contribution of the physical pairs. We have obtained a characteristic mass to the 46 elliptical pairs of 1.68 × 10^12 +/- 7.01 × 10^11 M_solar with M/L = 17.6 +/- 7.3 (H_0 = 60 km s^-1 Mpc^-1).

  7. Pair extended coupled cluster doubles

    SciTech Connect

    Henderson, Thomas M.; Scuseria, Gustavo E.; Bulik, Ireneusz W.

    2015-06-07

    The accurate and efficient description of strongly correlated systems remains an important challenge for computational methods. Doubly occupied configuration interaction (DOCI), in which all electrons are paired and no correlations which break these pairs are permitted, can in many cases provide an accurate account of strong correlations, albeit at combinatorial computational cost. Recently, there has been significant interest in a method we refer to as pair coupled cluster doubles (pCCD), a variant of coupled cluster doubles in which the electrons are paired. This is simply because pCCD provides energies nearly identical to those of DOCI, but at mean-field computational cost (disregarding the cost of the two-electron integral transformation). Here, we introduce the more complete pair extended coupled cluster doubles (pECCD) approach which, like pCCD, has mean-field cost and reproduces DOCI energetically. We show that unlike pCCD, pECCD also reproduces the DOCI wave function with high accuracy. Moreover, pECCD yields sensible albeit inexact results even for attractive interactions where pCCD breaks down.

  8. Fracking, fracture, and permeability

    NASA Astrophysics Data System (ADS)

    Turcotte, D. L.; Norris, J.; Rundle, J. B.

    2013-12-01

    Injections of large volumes of water into tight shale reservoirs allows the extraction of oil and gas not previously accessible. This large volume 'super' fracking induces damage that allows the oil and/or gas to flow to an extraction well. The purpose of this paper is to provide a model for understanding super fracking. We assume that water is injected from a small spherical cavity into a homogeneous elastic medium. The high pressure of the injected water generates hoop stresses that reactivate natural fractures in the tight shales. These fractures migrate outward as water is added creating a spherical shell of damaged rock. The porosity associated with these fractures is equal to the water volume injected. We obtain an analytic expression for this volume. We apply our model to a typical tight shale reservoir and show that the predicted water volumes are in good agreement with the volumes used in super fracking.

  9. Geometrically Frustrated Fracture Mechanics

    NASA Astrophysics Data System (ADS)

    Mitchell, Noah; Koning, Vinzenz; Vitelli, Vincenzo; Irvine, William T. M.

    2015-03-01

    When a flat elastic sheet is forced to conform to a surface with Gaussian curvature, stresses arise in the sheet. The mismatch between initial and final metrics gives rise to new fracture behavior which cannot be achieved by boundary loading alone. Using experiments of PDMS sheets frustrated on 3D-printed surfaces and a linearized analytical model, we demonstrate the ability of curvature to govern the sheets' fracture phenomenology. In this talk, we first show that curvature can both stimulate and suppress fracture initiation, depending on the position and orientation of the initial slit. Secondly, we show that curvature can steer the path of a crack as it propagates through the material. Lastly, the curvature can arrest cracks which would otherwise continue to propagate.

  10. DEM Particle Fracture Model

    SciTech Connect

    Zhang, Boning; Herbold, Eric B.; Homel, Michael A.; Regueiro, Richard A.

    2015-12-01

    An adaptive particle fracture model in poly-ellipsoidal Discrete Element Method is developed. The poly-ellipsoidal particle will break into several sub-poly-ellipsoids by Hoek-Brown fracture criterion based on continuum stress and the maximum tensile stress in contacts. Also Weibull theory is introduced to consider the statistics and size effects on particle strength. Finally, high strain-rate split Hopkinson pressure bar experiment of silica sand is simulated using this newly developed model. Comparisons with experiments show that our particle fracture model can capture the mechanical behavior of this experiment very well, both in stress-strain response and particle size redistribution. The effects of density and packings o the samples are also studied in numerical examples.