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To study the effect of sequence on DNA structure, the two decamer crystal structures one alternating, d(GTACGCGTAC), and the other non-alternating, d(GGCCGCGGCC), were solved. Crystals of both decamers belong to the hexagonal space group P6 1 22, with one strand in the asymmetric unit. The unit cell constants of the alternating decamer are a = b = 39.26 A, c = 77.70 A. The structure was refined with 1,828 reflections from 8.0 to 2.0 A resolution to an R value of 21.3% with all DNA atoms and 63 water molecules. The isomorphous non-alternating decamer had unit cell dimensions of a = b = 39.05 A, c = 82.15 A. The structure was refined with 2,423 reflections from 8.0 to 2.0 A resolution to a final R value of 22.2% for all DNA atoms and 65 water molecules. Although the average helical parameters of the decamers are typical of A-DNAs, there are some minor differences between them. The helical twist, rise, x-displacement, inclination and roll alternate in the alternating decamer, but do not in the non-alternating decamer. The backbone conformations in both structures show some differences; the residue G(7) of the alternating decamer is trans for a and ywhile the trans conformations are observed at the residue G(8) of the non-alternating decamer.

Ground and low-lying electronic states of Cr atoms in the gas phase were generated from photolysis of Cr(CO) 6 vapor in He or Ar using an unfocussed weak UV laser pulse and their reactions with O 2 and N2O were studied. When 0.5-1.0 Torr of Cr(CO)6 /O2 /He or Ar mixtures were photolyzed using 295-300 nm laser pulses, broadband chemiluminescence peaked at ~420 and ~500 nm, respectively, was observed in addition to the atomic emissions from z 7 P o , z 5 P o , and y 7 P o states of Cr atoms. When N2O was used instead of O2, no chemiluminescence was observed. The chemiluminescence intensities as well as the LIF intensities for those three low-lying electronic states (a 7 S3, a 5 S2 and a 5 DJ) showed second-order dependence on the photolysis laser power. Also, the chemiluminescence intensities were first-order in O 2 pressure, but the presence of excess Ar showed a strong inhibition effect on them. Based on the experimental results, the chemiluminecent species in this work is attributed to CrO 2* generated from hot ground state Cr atoms with O 2. The apparent radiative lifetimes of the chemiluminescent species and collisional quenching rate constants by O 2 and Ar also were investigated.

Vibronic relaxation among the Clements bands of SO2 molecule has been studied from time-resolved fluorescence spectra in the 300−350 nm region. The K‘ = 6, J‘ = 7 level of the Clements E-band was populated at 32 812.8 cm-1, and detailed time-resolved fluorescence spectra for the period 0−160 ns were obtained. Following the fast decay of the laser excited level, weak emissions from Clements A−F bands appeared almost simultaneously. The simultaneous appearance of many Clements bands was attributed to fast rovibronic relaxation of the laser excited molecules among the dark levels. It was also found that the broad apparent continuum emission following the direct fluorescence showed different decay rates at different wavelengths, but the decay rates of the emissions for λ > 350 nm were virtually identical. Based on the wavelength dependence of the decay rates, the apparent continuum emissions were ascribed to the emissions from the rovibronically dispersed hybrid bright states and the low-lying rovibrational l...

Crystallographic properties such as lattice constants, degree of c‐axis orientation, and c/a ratio of tetragonal Pb1−xLaxTiO3 (PLT, x=0–0.28) epitaxial thin films grown by pulsed laser deposition on single‐crystal substrates such as MgO(001) and SrTiO3(001) were evaluated. General x‐ray‐diffraction techniques—θ‐2θ scan and Φ scan—were used to confirm the epitaxial relations between films and substrates. The epitaxial relations were PLT(001) or (100)//substrate (001) and PLT[100] or [001]//substrate[100]. Then, using the {303} asymmetric rocking curve technique, more quantitative crystallographic informations of PLT films could be obtained. The c/a ratio and lattice constant along the a axis of c‐axis‐oriented PLT tetragonal unit cell were calculated from the peak location of {303} rocking curve, which is slightly different from that of the powder or bulk PLT. The existence of a‐axis‐oriented domains was also verified in PLT films grown on SrTiO3 substrate by {303} rocking curve. The origin of the observed...

Using an RNA/peptide dual-aptamer probe, both PSMA (+) and PSMA (−) prostate cancer cells were simultaneously detected by electrochemical impedance spectroscopy. This approach can be applied as a general tool for early diagnosis of prostate cancer.

In situ high‐Tc superconducting thin films of YBa2Cu3O7−x were deposited on (100) SrTiO3 substrate by laser ablation with a glancing angle geometry at different substrate temperatures in the 560–700 °C range. The transition temperatures, x‐ray diffraction patterns, and surface morphologies of the films were substantially different from one another. The critical temperatures of the films deposited at below 600 °C were 72–84 K, while the films deposited at above 650 °C showed Tc0 of 85–91 K. The x‐ray diffraction patterns and surface morphologies of the films showed that the orientations of the deposited films depended on the substrate temperature. The films deposited at 700 °C showed an exclusive orientation of ‘‘c’’ axis perpendicular to the (100) SrTiO3 substrate surface, but those deposited at below 600 °C exhibited random but a preferential orientation of c axis parallel to the (100) SrTiO3 surface. The dependence of the film orientations versus substrate temperature is explained in terms of lattice mi...

We have investigated the dissipation characteristics in the mixed state of ${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7\mathrm{\ensuremath{-}}\mathrm{\ensuremath{\delta}}}$ film, grown epitaxially on the ${\mathrm{SrTiO}}_{3}$(100) substrate, in terms of external transport current as well as magnetic field applied parallel to the c axis of the film. The dissipation fits well the thermally activated flux creep model, R=${\mathit{R}}_{0}$ exp(-U/${\mathit{k}}_{\mathit{B}}$T), where U is a function of electrical current, magnetic field, and temperature. In the range of current density \ensuremath{\sim}20\char21{}4000 A/${\mathrm{cm}}^{2}$, the current dependence of the activation energy U scales with ln(I/${\mathit{I}}_{0}$), as observed recently by Zeldov et al. U shows a power-law dependence on magnetic field as ${\mathit{H}}^{\mathrm{\ensuremath{-}}\mathrm{\ensuremath{\beta}}}$ with \ensuremath{\beta}=0.73\ifmmode\pm\else\textpm\fi{}0.002. We obtain the resistance prefactor ${\mathit{R}}_{0}$ proportional to the applied magnetic field, provided the Ginzburg-Landau-type magnetic-field suppression of the mean-field transition temperature ${\mathit{T}}_{\mathit{c}0}$ is taken into account. In addition, we present the magnetoresistance at various temperatures below ${\mathit{T}}_{\mathit{c}0}$, in good accordance with the flux-creep model.

We have fabricated three-dimensional (3D) photonic quantum ring lasers with an equilateral triangle microcavity. Their spectra were well explained by combining the off-normal resonance and hexagonally bounced in-plane whispering-gallery-mode condition. The angular distribution of the emission modes and their discrete wavelengths were shown to be in excellent agreement with a 3D Rayleigh Fabry-Perot model. We confirmed that the allowed modes in the equilateral triangle microcavity decrease by decreasing the length of equilateral triangle side, L, and the spectral mode spacing linearly increases with the mode index m and is inversely proportional to L2.

We have synthesized a family of bis-enediynes by two complementary Pd/Cu-catalyzed Sonogashira cross-coupling methods. One is a modified Sonogashira reaction between the TMS-protected tetraalkyne 20 (or 21) and various aromatic bromides to afford bis-enediynes 22a-d and 23a-d bearing different peripheral aryl units. The other, the reaction of bifunctional 1,1-dibromo-1-alkenes with phenylacetylene, afforded a series of bis-enediynes 24-32 bearing various core aryl groups. These chemical modifications to the core and periphery of bis-enediynes induce dramatic changes in absorption and emission spectra. Bis-enediynes 22 and 23 show a large Stokes shift of about 50-110 nm when compared to the less-conjugated bis-enediynes 20 and 21. Absorptions and emissions of bis-enediynes 25, 27-29, and 31 were red-shifted relative to those of enediyne 35. Substantial increases in fluorescence quantum yields are observed as a result of extending the pi-conjugation. The emission wavelength of bis-enediynes was tailored from indigo blue to reddish-orange, suggesting that the color of emission can be tunable by modification of the core and/or peripheral units.

From three dimensional whispering gallery cavities of GaAs photonic quantum ring fabricated in hyperboloid drum shape by chemically assisted ion beam etching with the central active region diameter of 0.9μm, we have observed single mode lasing near 838nm with a record low injection threshold of 300nA (Jth=47.1A∕cm2) in continuous wave operation at room temperature. This indicates that the quantum ring lasing phenomena associated with the three dimensional whispering gallery modes continue to persist, even at the submicron range overcoming the conventional two dimensional whispering gallery mode limit.

A commonly used buffer, 2,2-bis(hydroxymethyl)-2,2′,2″-nitrilotriethanol (Bis-Tris) coordinates lanthanide(III) ion strongly in water to form molecular species that are highly active for the hydrolysis of a phosphate diester, bis(4-nitrophenyl) phosphate.