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201 - 225 of 1,952
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CreatorTitleDescriptionSubjectDate
201 Armentrout, Peter B.Reactions of Pt+ with H2, D2, and HD: effect of lanthanide contraction on reactivity and thermochemistryA 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; Dihydrogen2002
202 Williams, Clayton C.High resolution photothermal laser probeAt 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 wafer1984
203 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; Hypoxanthines1973-11
204 Potts, Wayne K.Relationship of virulence factor expression to evolved virulence in mouse-passaged Cryptococcus neoformans linesSerial 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; Passage2005
205 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; Methionine1967-09-01
206 Olivera, Baldomero M.Nicotinic acetylcholine receptor ligand of unique specificity, α-conotoxin ImIWe 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 ImI1994
207 Dale, Colin; Babst, MarkusQuorum sensing primes the oxidative stress response in the insect endosymbiont, Sodalis glossinidiusSodalis 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 response2008
208 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 mechanismsThe 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 ions2001
209 Morse, Michael DavidSpin-forbidden c??+??X??+ band system of YFOptical spectra of jet-cooled diatomic YF have been recorded using resonant two-photon ionization spectroscopy. A vibrational progression corresponding to the c 3?1+?X 1?+ system has been identified. The vibrational frequency ?e' and anharmonicity ?'exe' of the c 3?+ state are 546.70 and 2.45 cm?1,...2007
210 DeTar, CarletonUpdate on fBWe describe the current status of the MILC collaboration computation of fB, fBs , fD, fDs and their ratios. Progress over the past year includes: better statistics and plateaus at _x000C_β = 6.52 (quenched), β_x000C_ = 5.6 (NF = 2) and β_x000C_ = 5.445 (NF = 2), new runs with a wide range of dyn...Decay constants; Wilson quarks1997-02
211 Boll, Steven F.Improving linear prediction analysis of noisy speech by predictive noise cancellationThe analysis of speech using Linear Prediction is reformulated to account for the presence of acoustically added noise and a technique is presented for reducing its effect on parameter estimation. The method, called Predictive Noise Cancellation (PNC), modifies the noisy speech autocorrelations ...Linear prediction; Predictive Noise Cancellation; Noisy speech; Sppech analysis1977
212 Olivera, Baldomero M.Poly(ADP-ribosylation) of a DNA topoisomeraseA DNA topoisomerase activity, copurifying with poly(ADP-ribose) synthetase from calf thymus, >95% inhibited if extensive poly(ADP-ribosylation) is allowed to occur. The inhibited DNA topoisomerase, which has drastically different elution properties on hydroxylapatite, can be reactivated by mild alka...Nicotinic acid; ADP-ribosylation; Turnover cycle; Synthetases1983
213 Kieda, David B.Toward a revival of stellar intensity interferometryBuilding on technological developments over the last 35 years, intensity interferometry now appears a feasible option by which to achieve diffraction-limited imaging over a square-kilometer synthetic aperture. Upcoming Atmospheric Cherenkov Telescope projects will consist of up to 100 telescopes, ...Intensity interferometry; Air Cherenkov Telescope2008
214 Miller, Joel StevenEffect of thermal annealing on the ferrimagnetic behavior and ordering of the [MnTXPP]+[TCNE].-.solv (X=F, Cl, Br, I; solv = PhMe, CH2Cl2) family of magnets+5,10,15,20-Tetrakis(4-fluorophenyl)porphyrinatomanganese(III) tetracyanoethenide, [MnTFPP][TCNE], 1F, 5,10,15,20-tetrakis(4-bromophenyl)porphyrinatomanganese(III) tetracyanoethenide, [MnTBrPP][TCNE], 1Br, and 5,10,15,20-tetrakis(4-iodophenyl)porphyrinatomanganese(III) tetracyanoethenide, [MnTIPP][T...Magnetic; Coupling2000
215 Symko, Orest GeorgeScattering times and mean free path in AlCuFe quasicrystalline thin filmsWe present magnetoresistivity measurements on AlCuFe quasicrystalline thin films from which the temperature dependence of the inelastic scattering time (ri e) has been deduced down to 200 mK in the low field limit. We show that ri e presents a weak temperature dependence below 4 K (1/ гie ~ T°-87)...AlCuFe; Quasicrystalline thin films; Scattering times; Free path1995-05
216 Vardeny, Zeev ValentinePhotoexcitations in polythiophene at high pressureWe report optical-absorption, photoluminescence (PL), and picosecond photoinduced absorption (PA) decay in films of poly-3-hexyl-thiophene at pressures up to 80 kbar. The spectral bands redshift nonlinearly with pressure and the PL intensity decreases markedly. Thermochromic transitions are complete...Photoexcitations1993-01
217 Olivera, Baldomero M.; Bandyopadhyay, Pradip K.Molecular phylogeny of some Indo-Pacific genera in the subfamily Turrinae H. Adams and A. Adams, 1853 (1838) (Gastropoda: Neogastropoda)We have carried out a phylogenetic analysis of a group of Indo-Pacific species in the subfamily Turrinae (Swainson, 1840) using 128 mitoehondrial ribosomal RNA gene sequcnces Most of the species analyzed are convenlionally assigned to one of there Lophiotoma Casey, 1904. The inolecular anaysis revea...Turrinae; Indo-Pacific; Mitochondrial RNA; Molecular phylogeny2007
218 Bohs, Lynn A.Cyphomandra (Solanaceae)Cyphomandra betacea (Cavanilles) Sendtner Syn. Cyphomandra crassifotia (Ortega) Kuntze, Solanum betacea Cavanilles, Solanwn crassifolium Ortega. Ref. FB 13(5B/1) 1962: 12; Bohs, 1986: 170. Cultivated tree. Andean II. 1000-3000 m. Voucher: Nunez et al. 8257 (MO!) Depts.: AM, CU, HU, SMCyphomandra; Solanum1993
219 Rogachev, AndreySuperconductor-insulator transition in long MoGe nanowires2012-01-01
220 Lupton, John MarkOn-chain defect emission in electroluminescent polyfluorenesWe present time-resolved photoluminescence measurements on a range of poly- and oligofluorenes with different molecular weights in both dilute solution and thin films. The commonly observed parasitic broad green emission band, which has previously been attributed to an excimer, is identified in all...Defect emission; Parasitic broad green emission band2002
221 Baehr, Wolfgang; Frederick, Jeanne M.; Church-Kopish, Jill; Howes, KimberlyMutant rhodopsin transgene expression on a null backgroundPURPOSE. To study mechanisms leading to photoreceptor degeneration in mouse models for autosomal dominant retinitis pigmentosa (adRP) based on the rhodopsin P23H mutation. METHODS. Mice of a transgenic line expressing a rhodopsin triple mutant, V20G, P23H, and P27L (GHL), were mated with rhodopsin (...Mutant Rhodopsin; Photoreceptor Degeneration; Autosomal Dominant Retinitis Pigmentosa; Rhodopsin2001-03
222 Saam, Brian; Pugmire, Ronald J.Gas-phase spin relaxation of 129XeWe have completed an extensive study of 129Xe longitudinal spin relaxation in the gas phase, involving both intrinsic and extrinsic mechanisms. The dominant intrinsic relaxation is mediated by the formation of persistent Xe2 van der Waals dimers. The dependence of this relaxation on applied magnetic...129Xe; Gas-phase spin relaxation2008-10
223 Vardeny, Zeev ValentineUltrafast dynamics in metallic and semiconducting carbon nanotubesTransient polarized pump/probe transmission changes upon pulse photoexcitation at 1.6 eV were measured in chiral enriched carbon nanotubes ensembles of both metallic and semiconductor characters, in a very broad probe spectral range from mid-IR to visible, combining several ultrafast laser systems...2009-11
224 Symko, Orest GeorgeApplication of SQUID magnetometer to nuclear magnetic thermometryThis paper presents an application of a SQUID magnetometer for low temperature thermometry using the magnetic properties of a nuclear paramagnet. The static magnetization of a material which obeys Curie's law provides a very sensitive means of thermometry. Also included in the device is the capabi...SQUID magnetometer; Nuclear magnetic thermometry; Low temperature thermometry1976
225 Miller, Joel StevenIsolation and structural determination of {(1,1,2,2-tetracyano-1,2-ethanediyl)bis[imino(cyanomethylene)]}bis-(cyanamide) ion(2--), [C12N12]2--, a new cyanocarbonThe oxidative degradation of [N(PPh3)2]3[Mnilll(CN)6] leads to the isolation of the unprecedented [C12N12]2- dianion, which is characterized by single-crystal X-ray diffraction and spectroscopic techniques.Cyanogen; Bond; Absorptions1995
201 - 225 of 1,952