Materials Literature
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A new core−sheath structure constructed by two kinds of molecular conformations 2/1 helix (α-form) and planar zigzag (β-form) conformations in biodegradable poly[( R )-3-hydroxybutyrate] (P(3HB)) fiber was revealed by 0.5 μm microbeam X-ray diffraction in synchrotron radiation. P(3HB) fiber processed by a method combi…
Structural and rheological properties of hydrogels made up of neutral bile acid derivatives are studied. Complementary scattering, diffraction, and microscopy techniques provide a precise structural description of the network architecture and its variation as a function of concentration, aging time, composition of the…
A series of semicrystalline block copolymers, poly(4-vinylpyridine)- block -poly(ε-caprolactone) (P4VP−PCL), with lamellar microstructure have been synthesized. Owing to the vitrified P4VP microdomains and strongly segregated microphase separation, the crystallization of the PCL blocks in P4VP−PCL was carried out with…
The use of Raman spectroscopy to detect nano-sized diamond crystals is controversial; the origins of peaks at $\ensuremath{\sim}1150\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}$ in chemical vapor deposition nanodiamond films and $\ensuremath{\sim}500\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-…
[structure: see text] Organic-inorganic hybrids synthesized from lacunary polyoxotungstates (POMs) have been screened as oxidation catalysts with H2O2 under MW irradiation. Yields up to 99% have been obtained in 25-50 min depending both on the POM structure and on the organic moiety. The reaction scope, optimized with…
Intrinsic ferromagnetism in the high-quality wurtzite ${\mathrm{Ga}}_{0.937}{\mathrm{Mn}}_{0.063}\mathrm{N}$ semiconductor is unambiguously demonstrated by both macroscopic magnetization measurements and x-ray magnetic circular dichroism. The structural quality of the samples grown by plasma-assisted molecular beam ep…
The use of atom transfer radical polymerization to grow poly(2-hydroxyethyl methacrylate) (PHEMA) brushes in porous alumina followed by functionalization of the PHEMA with nitrilotriacetate−Cu 2+ complexes yields membranes that adsorb proteins via coordination of Cu 2+ to histidine residues. Adsorption isotherms show…
Posttranslational modification is an efficient mechanism for controlling the activity of structural proteins, gene expression regulators, and enzymes in response to rapidly changing physiological conditions. Here we report in vitro and in vivo evidence that the acuABC operon of the gram-positive soil bacterium Bacillu…
We study localization properties of the Dirac-like electronic states in monolayers of graphite. In the framework of a general disorder model, we discuss the conditions under which such standard localization effects as the logarithmic temperature-dependent conductivity correction appear to be strongly suppressed, as co…
Mesoporous carbons with extremely large pore volume ( approximately 6 cm3/g) and narrow bimodal pore size distribution were synthesized by using 24 nm silica colloids as template.
We have developed a two-phase approach for the synthesis of shape-controlled colloidal zirconia nanocrystals, including spherical-, teardrop-, rod-, and rice grain-shaped particles. We found that the key factors for controlling the shape were the reaction time, the nature of the capping agent, and the monomer concentr…
In these experiments, double-stranded, linear DNA sequences were adsorbed into the pores of spherically shaped acid-prepared mesoporous silica (APMS). The lengths of the sequences were either 760 base pairs or 2000 base pairs. DNA adsorption into the interior of the mesoporous material was confirmed using confocal mic…
The valley splitting of the first few Landau levels is calculated as a function of the magnetic field for electrons confined in a strained silicon quantum well grown on a tilted SiGe substrate, using a parameterized tight-binding method. For a zero substrate tilt angle, the valley splitting slightly decreases with inc…
Gold-tipped CdSe rods (nanodumbbells) were solubilized in an aqueous phase and self-assembled in a head-to-tail manner using biotin disulfide and avidin. The disulfide end of the biotin molecule attaches to the gold tip of the nanodumbbell, and the biotin end of the molecule is able to conjugate to an avidin protein.…
Gibbs free-energy calculations based on density functional theory have been used to determine the possible source of failure of boron carbide just above the Hugoniot elastic limit (HEL). A range of B4C polytypes is found to be stable at room pressure. The energetic barrier for shock amorphization of boron carbide is b…
The floating-zone method and high-pressure synthesis have been used to obtain the hexagonal and the perovskite $R\mathrm{Mn}{\mathrm{O}}_{3}$ $(R=\mathrm{Y},\phantom{\rule{0.3em}{0ex}}\mathrm{Ho},\phantom{\rule{0.3em}{0ex}}\mathrm{Er},\phantom{\rule{0.3em}{0ex}}\mathrm{Tm},\mathrm{Yb},\phantom{\rule{0.3em}{0ex}}\mathr…
We discuss the influence of electrical effects on spin transport, and in particular the propagation and relaxation of spin polarized electrons in the presence of inhomogeneous electric fields. We show that the spin relaxation length strongly depends on electric field gradients, and that significant suppression of elec…
We deposited thin layers of CdS and ZnS nanoparticles embedded in a thermoplastic cyclo-olephin copolymer (COC) with elevated optical transparency and highly bio-compatible. The nanoparticles were obtained by thiolate precursors previously dispersed in the polymer upon thermal treatment at temperatures ranging between…
Comments on "Giant Dielectric Response in the One-Dimensional Charge-Ordered Semiconductor (NbSe_{4})_{3}I" (D. Staresinic et al., Phys. Rev. Lett. 96, 046402 (2006)) and "Colossal Magnetocapacitance and Colossal Magnetoresistance in HgCr_{2}S_{4}" (S. Weber et al., Phys. Rev. Lett. 96, 157202 (2006))
We report direct experimental evidence of the effect of quenched random field on magnetic ordering of La_(0.5)Gd_(0.2)Sr_(0.3)MnO_(3) manganites system. We demonstrate magnetic measurements providing serious evidence to support that quenched random field of Gd divides the system in finite size clusters which undergo c…