Materials Literature
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The magnetic and transport properties of the ${\mathrm{Pr}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{MnO}}_{3}$ system were studied at the characteristic points of the phase diagram corresponding to the ferromagnetic insulating and charge-ordered antiferromagnetic states. The magnetization M and resistivity $\ensur…
Photodynamic molecular architectures have been synthesized by covalent fixation of a photoisomerizable dimethylazobenzene group at two fixed points of conformationally flexible pi-conjugated quater- and sexithiophene chains. Theoretical geometry optimization shows, in excellent agreement with crystallographic structur…
Sol–gel derived titanium dioxide (TiO 2 ) films are prepared on silicon substrates using the method of spin-coating with different speeds from 1000 to 6000 rpm. Spectroscopic ellipsometric measurements provide dispersion of the refractive index and extinction coefficient within the wavelength range of 300–1000 nm. The…
Using molecular dynamics simulations we study the interactions between elongated colloidal particles (length to breath ratio >>1) in a nematic host. The simulation results are compared to the results of a Landau-de Gennes elastic free energy. We find that depletion forces dominate for the sizes of the colloidal partic…
Here we report on the study of ZnS and X-doped ZnS (with 4 at% of X = Al, Sn) thin films, prepared by spray pyrolysis technique using chloride precursors. Cathodoluminescence imaging and spectroscopy, x-ray diffraction, x-ray energy dispersive spectrometry and spectrophotometry have been used for their characterizatio…
$\ensuremath{\beta}\ensuremath{-}{\mathrm{MnO}}_{2}$ has a well-known screw type magnetic structure. According to Yoshimori [J. Phys. Soc. Jpn. 14, 807 (1959)] the pitch of this screw is exactly $\frac{7}{2}c.$ We performed neutron powder diffraction measurements which show that the pitch of the screw is about 4% shor…
Seeing red: A new methodology for the on-bead screening of proteins has been developed with the aid of red-emitting quantum dots. Use of this nanomaterial allowed a dual-color fluorescence assay to be developed that overcomes the limitation of the autofluorescence of TentaGel beads. The figure shows a positive control…
Convex and concave diffraction gratings are required for concentric imaging spectrometer forms. Direct-write electron-beam lithography has proven to be an effective method for fabricating high-efficiency blazed gratings on non-flat substrates. Recently fabricated convex gratings have demonstrated relative efficiency g…
New crown-appended cholesterol-based organogelators 1-3, which have one or two cholesterol skeletons as a chiral aggregate-forming site, two amino groups as an acidic proton binding site, and one crown moiety as a cation binding site, were synthesized, and the gelation ability was evaluated in organic solvents. These…
The order in a single layer of spherical domains of a block copolymer melt is investigated as a function of distance from the edges of the 15 microm wide, 30 nm deep wells that confine it along a substrate. At 255 degrees C the edge induces the formation of a hexatic phase whose orientational and translational order d…
Calmodulin (CaM) is a second messenger protein that has evolved to bind tightly to a variety of targets and, as such, exhibits low binding specificity. We redesigned CaM by using a computational protein design algorithm to improve its binding specificity for one of its targets, smooth muscle myosin light chain kinase…
One of the latest developments in electron microscopy is the environmental scanning electron microscope (ESEM), which enables soft, moist and/or electrically insulating materials to be viewed without pre-treatment, unlike conventional scanning electron microscopy, in which specimens must be solid, dry and usually elec…
We study the nucleation of GaN islands grown by plasma-assisted molecular-beam epitaxy on AlN(0001) in a Stranski-Krastanov mode. In particular, we assess the variation of their height and density as a function of GaN coverage. We show that the GaN growth passes four stages: initially, the growth is layer-by-layer; su…
A series of dinuclear platinum(II)-lanthanide(iii) complexes has been prepared in which a square-planar Pt(II) unit, either [(PPh(3))(2)Pt(pdo)] (H(2)pdo=5,6-dihydroxyphenanthroline) or [Cl(2)Pt(dppz)] [dppz=2,3-bis(2-pyridyl)pyrazine], is connected to a Ln(dik)(3) unit ("dik"=a 1,3-diketonate ligand). The mononuclear…
We analyze electron transport through a quantum shuttle for the applied voltage below the instability threshold. We obtain current-voltage characteristics of this system and show that at low temperature they exhibit pronounced steps. The temperature dependence of the current is calculated in the range from 2K to 300K…
From both theory and experiment, scattering of minority electrons is expected to be weaker than scattering of majority electrons in both dilute Fe(Cr) alloys and at Fe(Cr)/Cr interfaces. We show that Fe(Cr)/Cr/Fe(Cr) trilayer nanopillars display a normal magnetoresistance--i.e., largest resistance at low magnetic fiel…
It has been suggested that icosahedral short-range order (SRO) occurs in deeply undercooled melts of pure metallic elements. We report results of first-principles molecular dynamics simulations for stable and undercooled zirconium liquids. Our results emphasize the occurrence of a local order more complex than the ico…
Abstract The reaction mechanism of chitosan, bovine serum albumin (BSA), and gelatin with genipin (a natural crosslinking reagent) was examined with infrared, ultraviolet–visible, and 13 C NMR spectroscopies; protein‐transfer reaction mass spectrometry; photon correlation spectroscopy; and dynamic oscillatory rheometr…
In Salmonella enterica serovar Typhimurium, gmk encodes guanylate kinase, an essential enzyme involved in the synthesis and salvage of guanine nucleotides. Here we report the isolation of a mutation in gmk that results in a nutritional requirement for adenine at low temperature. Comparisons of kinetic parameters from…
We report the application of time- and polarization-resolved photoluminescence up-conversion spectroscopy to the study of spin capture and energy relaxation in positively and negatively charged, as well as neutral, InAs self-assembled quantum dots. When compared to the neutral dots, we find that carrier capture and re…