Search Results - (Author, Cooperation:D. Sandman)
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1Latest Papers from Table of Contents or Articles in PressStaff View
Publication Date: 2018-05-11Publisher: American Association for the Advancement of Science (AAAS)Print ISSN: 0036-8075Electronic ISSN: 1095-9203Topics: BiologyChemistry and PharmacologyGeosciencesComputer ScienceMedicineNatural Sciences in GeneralPhysicsKeywords: Medicine, DiseasesPublished by: -
2Latest Papers from Table of Contents or Articles in PressJ. A. Miller ; S. L. Ding ; S. M. Sunkin ; K. A. Smith ; L. Ng ; A. Szafer ; A. Ebbert ; Z. L. Riley ; J. J. Royall ; K. Aiona ; J. M. Arnold ; C. Bennet ; D. Bertagnolli ; K. Brouner ; S. Butler ; S. Caldejon ; A. Carey ; C. Cuhaciyan ; R. A. Dalley ; N. Dee ; T. A. Dolbeare ; B. A. Facer ; D. Feng ; T. P. Fliss ; G. Gee ; J. Goldy ; L. Gourley ; B. W. Gregor ; G. Gu ; R. E. Howard ; J. M. Jochim ; C. L. Kuan ; C. Lau ; C. K. Lee ; F. Lee ; T. A. Lemon ; P. Lesnar ; B. McMurray ; N. Mastan ; N. Mosqueda ; T. Naluai-Cecchini ; N. K. Ngo ; J. Nyhus ; A. Oldre ; E. Olson ; J. Parente ; P. D. Parker ; S. E. Parry ; A. Stevens ; M. Pletikos ; M. Reding ; K. Roll ; D. Sandman ; M. Sarreal ; S. Shapouri ; N. V. Shapovalova ; E. H. Shen ; N. Sjoquist ; C. R. Slaughterbeck ; M. Smith ; A. J. Sodt ; D. Williams ; L. Zollei ; B. Fischl ; M. B. Gerstein ; D. H. Geschwind ; I. A. Glass ; M. J. Hawrylycz ; R. F. Hevner ; H. Huang ; A. R. Jones ; J. A. Knowles ; P. Levitt ; J. W. Phillips ; N. Sestan ; P. Wohnoutka ; C. Dang ; A. Bernard ; J. G. Hohmann ; E. S. Lein
Nature Publishing Group (NPG)
Published 2014Staff ViewPublication Date: 2014-04-04Publisher: Nature Publishing Group (NPG)Print ISSN: 0028-0836Electronic ISSN: 1476-4687Topics: BiologyChemistry and PharmacologyMedicineNatural Sciences in GeneralPhysicsKeywords: Anatomy, Artistic ; Animals ; Atlases as Topic ; Brain/embryology/*metabolism ; Conserved Sequence/genetics ; Fetus/cytology/embryology/*metabolism ; Gene Expression Regulation, Developmental/*genetics ; Gene Regulatory Networks/genetics ; Humans ; Mice ; Neocortex/embryology/metabolism ; Species Specificity ; *TranscriptomePublished by: -
3Articles: DFG German National LicensesGeddes, N. J. ; Sambles, J. R. ; Jarvis, D. J. ; Parker, W. G. ; Sandman, D. J.
[S.l.] : American Institute of Physics (AIP)
Published 1992Staff ViewISSN: 1089-7550Source: AIP Digital ArchiveTopics: PhysicsNotes: Both ac and dc conduction processes through thin Langmuir–Blodgett (LB) films of the dodecyloxyphenylurethane of 2-bromo-5 (2'-hydroxyethoxy) tetracyanoquinodimethan (DDOP-C-TCNQ, a redox-active molecule) sandwiched between dissimilar metal (Pt and Mg) electrodes have been studied. The dc conduction changed from a linear I/V characteristic for the lowest applied voltages (±20 mV) to a symmetric nonlinear characteristic obeying a ln I∝V1/4 dependence for voltages up to ±1.5 V, in as-prepared samples. For larger positive voltages, a large increase in current was observed with the dependence changing to a ln I∝V3 law, a dependence not reported previously for metal/LB film/metal systems. For increased negative voltages, the ln I∝V1/4 was again observed. For low applied ac fields, the conductance was found to follow a ωn law with a value of n close to 0.8. The effect of heat annealing the samples was also studied with significant differences in the observed changes in conductance between bilayer and monolayer structures. Emphasis was placed on understanding the conduction process through the single DDOP-C-BHTCNQ layer film. For the monolayer device, hysteresis is observed in the positive bias, and both as-prepared and annealed samples exhibit ln I∝V3 behavior. Such behavior was not observed for the corresponding negative voltages, indicating rectification across a distance approximated by the length of an individual molecule. Possible models of the three-dimensional arrays for both monolayer and multilayer metal/LB film/Mg structures are presented. The weight of existing experimental results does not support the Aviram–Ratner "molecular rectifier'' concept for presently known Pt/LB monolayer/Mg devices.Type of Medium: Electronic ResourceURL: -
4Articles: DFG German National LicensesElman, B. S. ; Thakur, M. K. ; Sandman, D. J. ; Newkirk, M. A. ; Kennedy, E. F.
[S.l.] : American Institute of Physics (AIP)
Published 1985Staff ViewISSN: 1089-7550Source: AIP Digital ArchiveTopics: PhysicsNotes: Effects of 150-keV arsenic ion implantation on polydiacetylene crystals are characterized with respect to modifications of structural, electrical, and optical properties of the parent materials. Structural modifications are studied by means of Rutherford backscattering spectrometry, Raman spectroscopy, and x-ray photoelectron spectroscopy. It is demonstrated that at low and intermediate fluences of implantation, structural changes are mainly associated with effects of the ion beam on the polymer side groups. dc resistivity measurements were performed in the 20 °K〈T〈290 °K temperature range and the results yield an exponential behavior of the resistivity ρ(T)=ρ0 exp(T0/T)m with the temperature-dependent exponential factor 1/2〈m〈1 where m → 1 at higher temperatures (T〉190 °K) and m → 1/2 at lower temperatures (T〈80 °K). Absorption spectra in the visible range from ion-implanted thin crystalline films are also presented and discussed.Type of Medium: Electronic ResourceURL: -
5Articles: DFG German National LicensesGeddes, N. J. ; Sambles, J. R. ; Jarvis, D. J. ; Parker, W. G. ; Sandman, D. J.
Woodbury, NY : American Institute of Physics (AIP)
Published 1990Staff ViewISSN: 1077-3118Source: AIP Digital ArchiveTopics: PhysicsNotes: Metal/Langmuir–Blodgett monolayer/metal devices, where the monolayer consists of the dodecyloxyphenylcarbamate of 2-bromo, 5(2'-hydroxyethoxy) tetracyanoquinodimethan, a donor-σ-acceptor molecular system, have been constructed, and dc current-voltage (I-V) characteristics of these devices were recorded at room temperature. For biases of ±20 mV, the I-V characteristics are linear, changing to a nonlinear form for higher voltages. This nonlinear characteristic exhibited a ln(I)∝V1/4 dependence for both positive and negative voltages up to ±1 V. For positive voltages 〉+2.0 V for as-prepared devices and 〉+1.5 V for annealed devices, a ln(I)∝V3 dependence was observed, revealing a very large increase in current for small voltage changes. Such behavior was not observed for corresponding negative voltages, indicating rectification across a distance approximated by the length of an individual molecule.Type of Medium: Electronic ResourceURL: -
6Articles: DFG German National LicensesEnhanced electrical conductivity of polydiacetylene crystals by chemical doping and ion implantationSakamoto, M. ; Wasserman, B. ; Dresselhaus, M. S. ; Wnek, G. E. ; Elman, B. S. ; Sandman, D. J.
[S.l.] : American Institute of Physics (AIP)
Published 1986Staff ViewISSN: 1089-7550Source: AIP Digital ArchiveTopics: PhysicsNotes: The conductivity enhancement in polydiacetylene (PDA) crystals due to chemical doping and ion implantation was measured and analyzed in relation to their spin concentration and photocurrent decay based on the structural and optical information obtained through infrared and visible reflectivity spectra. A conductivity jump was observed upon slight increase of the spin concentration at low doping levels of chemically doped PDAs, suggesting the formation of spinless carriers in chemically doped PDAs, as in trans-polyacetylene and poly(p-phenylene). In contrast, in ion-implanted samples, a great difference in the magnitudes (by more than five orders of magnitude) was observed between the conductivity enhancement for two PDAs having different side chain species. Furthermore, the photocurrent decay time measurements reveal different distributions of implantation-induced trap levels between ion-implanted poly [2,4-hexadiyne-1,6-diol-bis-(p-toluene sulfonate)] (PTS) and poly[2,4-hexadiyne-1,6-di(N-carbazolyl)] (DCH). A conduction mechanism which could explain the significant difference in conductivity enhancement between PTS and DCH is suggested. Because the enhanced conductivity by ion-implanted PTS showed no orientational effect associated with the polymer chain direction, a conductive path and network formation by the implantation-induced defects is more plausible for the conduction mechanism than carrier introduction into the backbone chain band from side chain defect levels.Type of Medium: Electronic ResourceURL: -
7Articles: DFG German National LicensesMasse, C. E. ; Conroy, J. L. ; Cazeca, M. ; Jiang, X. L. ; Sandman, D. J. ; Kumar, J. ; Tripathy, S. K.
New York, NY [u.a.] : Wiley-Blackwell
Published 1996Staff ViewISSN: 0021-8995Keywords: Chemistry ; Polymer and Materials ScienceSource: Wiley InterScience Backfile Collection 1832-2000Topics: Chemistry and PharmacologyMechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision MechanicsPhysicsNotes: The synthesis and characterization of a novel epoxy-based photocrosslinkable nonlinear optical (NLO) polymer exhibiting enhanced thermal stability is reported. The synthesized polymers show spectroscopic properties (NMR, IR, UV) in accordance with the proposed structures. A glass transition temperature (Tg) of 112°C and a thermal degradation temperature (Td) of 310°C were recorded. The poled polymer film exhibits stable second-order nonlinear optical activity (d33 = 19.5 pm/V) over a period of 500 h as characterized by the temporal response of the second harmonic signal at room temperature. © 1996 John Wiley & Sons, Inc.Additional Material: 1 Ill.Type of Medium: Electronic Resource -
8Articles: DFG German National LicensesShivshankar, V. ; Sung, C. ; Kumar, J. ; Tripathy, S. K. ; Sandman, D. J.
Weinheim : Wiley-Blackwell
Published 1997Staff ViewISSN: 0323-7648Keywords: Chemistry ; Polymer and Materials ScienceSource: Wiley InterScience Backfile Collection 1832-2000Topics: Chemistry and PharmacologyPhysicsNotes: Surface eruptions that are approximately 0.5 μm in diameter at the base and about 700 Å in height have been observed by atomic force microscopy on single crystals and films of polydiacetylenes of the alkylurethanes of 5,7-dodecadiyn-1,12-diol when the polymerization is performed using 60Co gamma radiation in the presence of air. The eruption process is associated with monomer polymerization and is anisotropic, as the eruptions are found only on the (100) face of single crystal specimens. Crystals having surface eruptions are irreversibly converted from blue to red at room temperature on exposure to a single pulse of 532 nm laser light while crystals lacking eruptions do not undergo this change.Additional Material: 5 Ill.Type of Medium: Electronic ResourceURL: