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Creator | Title | Description | Subject | Date |
| 276 |
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Vardeny, Zeev Valentine | Ultrafast electronic and acoustic effects in conducting polymers | The polarized picosecond pump and probe technique with 50 fsec resolution has been used to generate and detect electronic excitations and propagation of ultrasonic phonons in thin films of oriented and unoriented polyacetylene and polythiophene. We found that the photoexcitations are instantaneou... | Ultrafast electronic effects; Ultrafast acoustic effects; Polarized picosecond pump; Pump and probe technique; Ultrasonic phonons | 1990 |
| 277 |
 |
Miller, Joel Steven | Magnetically ordered molecule-based assemblies | The development of molecules and assemblies of molecules exhibiting technologically important bulk properties, such as magnetic ordering, is an important worldwide research focus. Organic- and molecule-based magnets have been discovered and several families have been reported with magnetic orderin... | Organic-based; Lattices; Magnets | 2006 |
| 278 |
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Olivera, Baldomero M.; McIntosh, J. Michael | Novel post-translational modification involving bromination of tryptophan: identification of the residue, L-6-bromotryptophan, in peptides from Conus imperialis and Conus radiatus venom | We report a novel post-translational modification involving halogenation of tryptophan in peptides recovered from the venom of carnivorous marine cone snails (Conus). The residue, L-6-bromotryptophan, was identified in the sequence of a heptapeptide, isolated from Conus imperialis, a worm-hunting... | Conotoxins; Conus imperialis; Conus radiatus; L-6-bromotryptophan | 1997 |
| 279 |
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Ehleringer, James R. ; Cerling, Thure E. | Aberrant water homeostasis detected by stable isotope analysis | While isotopes are frequently used as tracers in investigations of disease physiology (i.e., 14C labeled glucose), few studies have examined the impact that disease, and disease-related alterations in metabolism, may have on stable isotope ratios at natural abundance levels. The isotopic composition... | | 2010-07-21 |
| 280 |
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Sperry, John S. | Xylem hydraulics and the soil-plant-atmosphere continuum: opportunities and unresolved issues | Received for publication July 23, 2002. Soil and xylem are similar hydraulically. An unsaturated conductivity curve for soil is called a vulnerability curve for xylem?but the underlying physical basis is the same. Thus, any transport model that treats unsaturated soil conductivity would benefit by a... | Soil?plant?atmosphere continuum; Water potential | 2003 |
| 281 |
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Lupton, John Mark | Time-gated electroluminescence spectroscopy of polymer light-emitting diodes as a probe of carrier dynamics and trapping | We present time-gated electroluminescence (EL) spectroscopy of a polyfluorene-based conjugated polymer. The technique is shown to be sensitive enough to pick out impurity emission orders of magnitude weaker than the cw emission. By considering the temperature dependence of the delayed emission spect... | Time-gated electroluminescence spectroscopy; Carrier dynamics; Trapping; Delayed emission | 2002-04 |
| 282 |
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Morse, Michael David | Resonant two-photon ionization spectroscopy of jet-cooled Au? | A band system of jet-cooled Au, has been located in the near infrared region of the spectrum using resonant two-photon ionization spectroscopy. The origin band is located at 13 354.15 cm-? and the system extends more than 700 cm-? further to the blue. The excited state displays a radiative lifetime... | | 1991 |
| 283 |
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Capecchi, Mario R. | Hoxa1 lineage-tracing indicates a direct role for Hoxa1 in development of the inner ear, the heart and the third rhombomere | Loss of Hoxa1 function results in severe defects of the brainstem, inner ear and cranial ganglia in humans and mice as well as cardiovascular abnormalities in humans. Since Hoxa1 is expressed very transiently during an early embryonic stage, it has been difficult to determine whether Hoxa1 plays a d... | Hoxa1; Inner ear; Third rhombomere; Hindbrain; Hoxa1-IRES-Cre mouse; Embryonic development; Lineage-tracing | 2010 |
| 284 |
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Gondolo, Paolo | Fluid interpretation of Cardassian expansion | A fluid interpretation of Cardassian expansion is developed. Here, the Friedmann equation takes the form H2=g(ρM) where ρM contains only matter and radiation ~no vacuum!. The function g(ρM) returns to the usual 8πM /(3mpl 2 ) during the early history of the Universe, but takes a different form... | Cardassian expansion; Friedmann equation | 2003-09 |
| 285 |
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Vardeny, Zeev Valentine | Spin-dependent delayed luminescence from nongeminate pairs of polarons in ∏-conjugated polymers | We measured cw photoinduced absorption (PA) and spin- 1 2 PA- and photoluminescence detected magnetic resonance (PADMR and PLDMR, respectively) in films of two representative p-conjugated polymers; poly(phenylene-vinylene) and polythiophene. From the dependences of the polaron PA and PLDMR on the ... | pi-conjugated polymers; Nongeminate pairs; Spin-dependent delayed luminescence; Photoinduced absorption; Poly(phenylene-vinylene) | 2002-12 |
| 286 |
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Williams, Clayton C.; Stringfellow, Gerald B. | Effect of substrate misorientation on ordering in Ga0.5In0.5P | Ordering produced in Gao.5Ino.5P epitaxial layers grown by OMVPE can be controlled by variations in the substrate misorientation as well as the growth temperature and the growth rate. The ordering produced at a growth temperature of 620°C and a relatively low growth rate of 0.5 /μm/hr is found to ... | Ga0.5In0.5P; Epitaxial layers; Epitaxial growth; OMVPE | 1994 |
| 287 |
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Coley, Phyllis D. | Herbivory and defensive characteristics of tree species in a lowland tropical forest | Rate of herbivory and defensive characteristics of young and mature leaves were measured for saplings of 46 canopy tree species in a lowland tropical rain forest (Barro Colorado Island, Panama). Grazing rates were determined in the field for sample periods in the early wet, late wet, and dry seasons... | Fiber; Herbivory; Life history; Panama; Phenolics; Plant growth; Spatial distribution; Tannins; Temporal distribution; Treefall gaps; Tropical forest | 1983 |
| 288 |
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Symko, Orest George | Spin freezing below the nearest-neighbor percolation concentration in Cd1-xMnxTe and Cd1-xMnxSe | The very-low-temperature magnetization of Cdi_xMnxTe and Cdj-xMnxSe alloys shows spinglass behavior for concentrations below the nearest-neighbor percolation limit. This is attributed to short-range exchange and dipolar interactions. New magnetic phase diagrams for both systems are presented. | Spin freezing; Cd1-xMnxTe; Cd1-xMnxSe; Very-low-temperature magnetization; Spin-glass behavior | 1986-05 |
| 289 |
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Gerton, Jordan | Optimizing contrast of tip-enhanced fluorescence microscopy for imaging high-density samples | Quantum dots are imaged using tip-enhanced fluorescence microscopy. Optimization of the operation parameters leads to high-contrast images of high-density samples and a novel photon analysis improves contrast further. | | 2007-05 |
| 290 |
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Sperry, John S. | Winter xylem embolism and spring recovery in Betula cordifolia, Fagus grandifolia, Abies balsamea, and Picea rubens | Xylem embolism was monitored from mid-winter to mid-summer in four co-occurring species: Betula cordifolia (Reg.) Fern., Fagus grandifolia Ehrh., Abies balsamea (L.) Mill., Picea rubens Sarg. The study site was a west-facing slope in the northern Green Mountains of Vermont, U.S.A.; Betula and conife... | Conductivity; Hydraulic; Trees | 1993 |
| 291 |
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Olivera, Baldomero M. | Targeted mutagenesis by homologous recombination in D. melanogaster | We used a recently developed method to produce mutant alleles of five endogenous Drosophila genes, including the homolog of the p53 tumor suppressor. Transgenic expression of the FLP site-specific recombinase and the I-SceI endonuclease generates extrachromosomal linear DNA molecules in vivo. Thes... | | 2002 |
| 292 |
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Morse, Michael David | Vibronic spectroscopy of unsaturated transition metal complexes: CrC?H, CrCh?, and NiCH? | Vibronically resolved resonant two-photon ionization and dispersed fluorescence spectra of the organometallic radicals CrC2H, CrCH3 , and NiCH3 are reported in the visible and near-infrared wavelength regions. For CrC2H, a complicated vibronic spectrum is found in the 11 100?13 300 cm-1 region, with... | | 2004 |
| 293 |
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Armentrout, Peter B. | Reactions of Pt+ with H2, D2, and HD: effect of lanthanide contraction on reactivity and thermochemistry | A guided ion beam tandem mass spectrometer is used to examine the kinetic energy dependence of reactions of the third-row transition metal cation, Pt1, with molecular hydrogen and its isotopologs. A flow tube ion source produces Pt1 ions in its electronic ground state term and primarily in the lowes... | Metal clusters; Platinum ions; Lanthanide contraction; Bond energies; Endothermic reactions; Transition metal ions; Dihydrogen | 2002 |
| 294 |
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Williams, Clayton C. | High resolution photothermal laser probe | At frequencies near 1 GHz, the acoustic wavelength in argon gas becomes half that of visible light, making possible collinear Bragg scattering of laser light by the sound. This acousto-optic interaction has been used to detect photothermally generated acoustic power at the surface of solids. This ne... | Photothermal laser probe; Silicon wafer | 1984 |
| 295 |
 |
Capecchi, Mario R. | Altered enzymes in drug-resistant variants of mammalian tissue culture cells. | Two selective procedures are compared in an effort to isolate variants of mouse L cells containing structural gene mutations. Among the resulting variant cloned cell lines are found two types of alterations in theenzyme hypoxanthine phosphoribosyl transferase (EC 2.4.2.8.) (1): enzyme with altered ... | Drug Resistance; Azaguanine; Clone Cells; Hypoxanthines | 1973-11 |
| 296 |
 |
Potts, Wayne K. | Relationship of virulence factor expression to evolved virulence in mouse-passaged Cryptococcus neoformans lines | Serial passage of Cryptococcus neoformans in mice increases virulence relative to the nonpassaged line. Postpassaged lines showed no difference in the expression of most known virulence factors, with the exception that the more virulent lines had smaller capsules in vitro. These data imply that othe... | Capsule; Death; Passage | 2005 |
| 297 |
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Gussin, Gary N.; Capecchi, Mario R. | Protein synthesis directed by DNA phage messengers. | Even through the amino acids corresponding to most of the 64 nucleotide triplets are now known, several important aspects of the genetic code are not yet fully understood. In particular we need more knowledge about the "punctuation marks" of the code-for example, the signals necessary for the initia... | Carbon Isotopes; Escherichia coli; Genetic Code; Methionine | 1967-09-01 |
| 298 |
 |
Olivera, Baldomero M. | Nicotinic acetylcholine receptor ligand of unique specificity, α-conotoxin ImI | We report the isolation, characterization, and total synthesis of a small peptide ligand for nicotinic acetylcholine receptors (nAChRs). It is highly active against the neuromuscular receptor in frog but noitn mice. In contrast, it induces seizures when injected centrally in mice and rats, suggesti... | Conotoxins; a-conotoxin ImI | 1994 |
| 299 |
 |
Dale, Colin; Babst, Markus | Quorum sensing primes the oxidative stress response in the insect endosymbiont, Sodalis glossinidius | Sodalis glossinidius, a maternally transmitted bacterial endosymbiont of tsetse flies (Glossina spp.), uses an acylated homoserine lactone (AHL)-based quorum sensing system to modulate gene expression in accordance with bacterial cell density. The S. glossinidius quorum sensing system relies on the... | Endosymbionts; Sodalis glossinidius; Quorum sensing; Oxidative stress response | 2008 |
| 300 |
 |
Armentrout, Peter B. | Activation of methane by size-elected iron cluster cations, Fen+ (n=2-15): cluster-CHx (x=0-3) bond energies and reaction mechanisms | The kinetic energy dependences of the reactions of Fen + (n=2 - 15) with CD4 are studied in a guided ion beam tandem mass spectrometer over the energy range of 0-10 eV. All reactions exhibit thresholds and two main products, FenD+ and FenCD2+, are formed. | Metal clusters; Iron ions; Bond energies; Dehydrogenation; Endothermic reactions; Transition metal ions | 2001 |
