Materials Literature
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The final step of NAD+ biosynthesis includes an amide transfer to nicotinic acid adenine dinucleotide (NaAD) catalyzed by NAD+ synthetase. This enzyme was co-crystallized in microgravity with natural substrates NaAD and ATP at pH 8.5. The crystal was exposed to ammonium ions, synchrotron diffraction data were collecte…
Dendritic Ru-BINAP catalysts functionalized with alkyl chain at the periphery together with organic binary solvent system that exhibited phase separation induced by addition of a little water have been employed for asymmetric hydrogenation, leading to high catalytic activity and enantioselectivity as well as facile ca…
Two interesting organic–inorganic hybrid solids [{Cu(2,2′-bipy)2}2(β-Mo8O26)] (1), [{Cu(py)3}2{Cu(py)2}2(α-Mo8O26)] (2), and a new two-electron-reduced Keggin-core compound [Cu(py)2]4[Mo12O36(SO4)] (3), were synthesized by hydrothermal methods and structurally characterized by X-ray diffraction. The structure of 1 con…
Proton NMR second moment and spin—lattice relaxation times T 1 and T 1p have been studied for polycrystalline guanidinium hexachloroantimonate C(NH2)3SbCl6 in a wide temperature range. A dynamic inequivalence of two cations has been detected in spite of their crystal-lographical equivalence. Activation parameters for…
Three crystal structures have been analysed from the point of view of intermolecular interactions: N,N'-diphenyl-1,4-benzoquinone diimine, C(18)H(14)N(2), (I), its reduced form N,N'-diphenyl-1,4-phenylenediamine, C(18)H(16)N(2), (II), and N,N'-diphenyl-1,4-phenylenediammonium bis(p-toluenesulfonate), C(18)H(18)N(2)(2+…
The working principle of an optical isolator made of two corrugated dielectric gratings is introduced. One grating acts as a polarizer, and the other acts as a quarter-wave plate used in conical incidence converting linearly polarized light into circularly polarized light. Global maxima of diffraction efficiency for s…
The complex dielectric permittivity of concentrated aqueous alkaline aluminate solutions at total concentrations 1 ≲ [Al] T /mol dm -3 ≲ 6 with either [Na] T = 8.33 mol dm -3 or [Al] T /[Na] T = 0.750 has been determined at 25 °C in the frequency range 0.5 ≲ ν/GHz ≤ 20. All solution spectra could be represented as a s…
Screening for heavy-atom derivatives remains a time-consuming and cumbersome process that often results in non-isomorphous derivatives whose phases cannot be combined. Using lysozyme and FcgammaRIII receptor crystals as test cases, an improved soaking method for the generation of conventional heavy-atom derivatives ha…
Abstract A colloidal dispersion is a heterogeneous system in which particles of solid or droplets of liquid with dimensions of order 10 µm or less are dispersed in a liquid medium. Familiar examples of such systems include industrial and household products such as paints and inks, food products such as mayonnaise and…
The local thermal behavior of the Ag(2)O framework structure has been studied by extended x-ray absorption fine structure. The average Ag-O nearest-neighbor distance expands upon heating, while the Ag-Ag next-nearest-neighbor distance contracts. An original implementation of the cumulant analysis shows that the Ag-O e…
We have measured the specific heat between 0.5 and 20 K for three different solid phases of ethanol: the stable monoclinic crystal, the structural (amorphous) glass, and an orientationally disordered cubic crystalline phase (also named as orientational glass or ``glassy crystal''). We have therefore extended previous…
Carbon nanotubes show great promise for applications ranging from nanocomposites, nanoelectronic components, nanosensors, to nanoscale mechanical probes. These materials exhibit very attractive mechanical properties with extraordinarily high stiffness and strength, and are of great interest to researchers from both at…
Relaxation dynamics of ${\mathrm{Ag}}^{+}$ ions and scaling of the conductivity spectra in lead bismuthate glasses of different compositions have been investigated in the frequency range from 10 Hz to 2 MHz and in the temperature range from 83 K to just below glass transition temperature. We have observed that relaxat…
Insulin crystals suitable for cryogenic data collection and structure determination by single-wavelength anomalous scattering (SAS) were obtained by a self-optimization screening process in a single capillary tube without manipulation of the crystals at any time. Using the counter-diffusion crystallization technique,…
Heat capacities of ${\mathrm{ZrW}}_{2}{\mathrm{O}}_{8}$ and ${\mathrm{HfW}}_{2}{\mathrm{O}}_{8}$ were precisely measured between 1.8 and 330 K. Heat-capacity curves of ${\mathrm{ZrW}}_{2}{\mathrm{O}}_{8}$ and ${\mathrm{HfW}}_{2}{\mathrm{O}}_{8}$ are very similar to each other. The heat capacity of ${\mathrm{HfW}}_{2}{…
There is a growing interest in utilizing renewable resources and exploiting biological reactions for environmentally friendly products and processes. We report the use of the enzyme tyrosinase to graft the natural phenol, catechin, onto the biopolymer chitosan. Chemical evidence for grafting was obtained by UV/visible…
The structure, luminescence spectroscopy, and lifetime decay dynamics of Eu 2 O 3 nanoparticles formed in MCM-41 have been investigated. Both X-ray diffraction and high-resolution transmission electron microscopic observations indicate that Eu 2 O 3 nanoparticles of monoclinic structure are formed inside channels of M…
We present photoelectron spectroscopy investigations of in-situ prepared AgO. The sample was prepared by room temperature oxidation of Ag in an electron cyclotron resonance ${\mathrm{O}}_{2}$ plasma. In contrast to other measurements based on ex situ prepared AgO powder samples, our investigations show a distinct doub…
We present a theoretical survey of ferromagnetic transition temperatures in cubic (III,Mn)V semiconductors based on a model with $S=5/2$ local moments exchange coupled to itinerant holes in the host semiconductor valence band. Starting from the simplest mean-field theory of this model, we estimate the ${T}_{c}$ enhanc…
We have fabricated air-stable n-type, ambipolar carbon nanotube field effect transistors (CNFETs), and used them in nanoscale memory cells. N-type transistors are achieved by annealing of nanotubes in hydrogen gas and contacting them by cobalt electrodes. Scanning gate microscopy reveals that the bulk response of thes…