Materials Literature
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The combination of bioresorbable and biodegradable hydrophilic polysaccharides with biodegradable hydrophobic polyester chains to form totally biodegradable, nonionic brushlike amphiphilic graft copolymers useful as surfactants has been investigated. In fact, a totally controlled and original three-step procedure is d…
Thin organic films were deposited from plasmas of allyl alcohol, acrylic acid, allylamine, and octa-1,7-diene onto aluminum substrates. These plasma polymerized films were analyzed by X-ray photoelectron spectroscopy (XPS) before and after prolonged periods of storage under laboratory atmosphere to attempt to quantify…
Solution cast films were prepared from poly(L-lactide) (PLLA) and poly(epsilon-caprolactone) (PCL) as well as from three blends, namely B75, B50, and B25 with PLLA/PCL proportions of 75/25, 50/50, and 25/75, respectively. The enzymatic degradation of square samples (10 x 10 x 0.2 mm) cut from the films was investigate…
A novel hydrophilic macromer adapted for chemical grafting has been synthesized. It consists of methyl-end-capped poly(ethylene glycol) functionalized with a urethane terminus. Dispersion polymerization of styrene in an alcohol/water medium in the presence of the macromer allows chemical grafting of the macromer to th…
The molecular building blocks Fe(II)Pc (Pc = phthalocyaninato2-), Fe(III)Pc, ZnPc, Cp(dppe)Fe, and Cp(PPh3)2Ru were combined in the cyanide-bridged dinuclear reference compounds with M-CN-ZnPc and M-CN-FePc-CN arrays containing Fe(II)Pc and Fe(III)Pc. The linear trinuclear species with the M(mu-CN)Fe(mu-CN)M' backbone…
Narrow band gaps and high electron affinities are associated with the new oligomers containing thiophene-1-oxide and thiophene-dioxide that have been prepared by zirconocene coupling methods. A series of oligomers with 3–11 rings (X=2 H, S, and S(=O)2; see picture) allow the electronic properties of conjugated chains…
Two kinds of solventless liquid oligoesters, linear and three-armed, were synthesized by direct esterification of a mixture of diacids and diol or triol. The molecular weights of such oligoesters are in the range 800−1000. Linear oligoesters have a single melting point of between −5 and 0 °C while only one glass trans…
Stepwise assembly of isotactic poly(methyl methacrylate) and syndiotactic poly(methacrylic acid) from acetonitrile and mixed acetonitrile/water solutions, respectively, onto a gold substrate was studied. Quantitative quartz crystal microbalance analysis of the molar ratio (monomer unit) between assembled polymers sugg…
The crystal structures of gyceraldehyde 3-phosphate dehydrogenase (GAPDH) from Escherichia coli have been determined in three different enzymatic states, NAD(+)-free, NAD(+)-bound, and hemiacetal intermediate. The NAD(+)-free structure reported here has been determined from monoclinic and tetragonal crystal forms. The…
We use variational quantum Monte Carlo to calculate the density-functional exchange-correlation hole n_{xc}, the exchange-correlation energy density e_{xc}, and the total exchange-correlation energy E_{xc}, of several electron gas systems in which strong density inhomogeneities are induced by a cosine-wave potential.…
The relationship between paramagnetic defect centers and UV absorption bands simultaneously generated by ionizing radiation in Ge-doped SiO2 glass is investigated using magneto-optical techniques. A sample of 7.0 mol% Ge-doped SiO2 was exposed to X-ray radiation, which resulted in the formation of absorption bands cen…
Protein solubility (PS) values of different soy protein isolate (SPI) films were determined in water, 0.01 N HCl, 0.01 N NaOH, 4 M urea, and 0.2 M 2-mercaptoethanol. Tensile and color (L, a, and b values) properties of films also were determined. Control films were cast from heated (70 degrees C for 20 min), alkaline…
We consider the ordering kinetics of a nonconserved scalar field advected by a uniform shear flow. Using the Ohta-Jasnow-Kawasaki approximation (Ohta T, Jasnow D and Kawasaki K 1982 Phys. Rev. Lett. 49 1223), modified to allow for shear-induced anisotropy, we calculate the asymptotic time dependence of the characteris…
The local structure of Fe 2 O 3 –TeO 2 –B 2 O 3 –SrF 2 glasses was studied by recording the EPR and IR absorption spectra. Structural changes and increasing glass stability were evidenced with the addition of Fe 2 O 3 in the sample. The distribution of isolated paramagnetic ions in sites of strongly distorted octahedr…
Li/Ag and Li/Al electrochemical cells composed of smooth Ag or Al electrode sheets, respectively, and matched with nonaqueous electrolytes were assembled and discharged. Discharged Ag electrodes were investigated using micro-Raman spectromety. Raman bands attributed to the components of the passivating film on the sur…
The adsorption of a cationic luminescence probe, tris(2,2‘-bipyridine)ruthenium(II) ([Ru(bpy) 3 ] 2+ ), into a mesoporous silica was investigated in order to understand the nature of mesoporous silicas as immobilizing media for organic guest species. The adsorption of the probe into the mesoporous silica was conducted…
The adsorption of propene on Au(111) and Au(100) was investigated using temperature-programmed desorption (TPD) and high-resolution energy loss spectroscopy (HREELS). A desorption activation energy of 9.4 kcal/mol and very small shifts of the vibrational frequencies from their gas-phase values indicate that the intera…
The rupture of a medium under stress typifies breakdown phenomena. More generally, the latter encompass the dynamics of systems of many interacting elements governed by the interplay of a driving force with a pinning disorder, resulting in a macroscopic transition. A simple mean-field formalism incorporating these fea…
The transient network literature up to now has considered that the connection probability of a free strand does not depend on the strand extension, in contrast with the disconnection probability. We argue that, on thermodynamic grounds, both probabilities must have the same dependence on the strand extension. We propo…
Self-assembly of gold nanorods (NRs) with aspect ratio of ∼4.6 (12 nm in diameter and 50−60 nm in length) has been studied using transmission electron microscopy (TEM). Under appropriate conditions such as nanoparticle concentration, solvent evaporation, narrow size distribution, ionic strength, and surfactant concent…