Controlled synthesis of hydrophilic concentrated polymer brushes and their friction/lubrication properties in aqueous solutions

Polymer brushes of water‐soluble polymers, poly(2‐hydroxyethyl acrylate) (PHEA) and poly(poly(oxyethyleneglycol)methylether acrylate) (PPEGA), were synthesized on a silicon wafer and a silica particle by applying photo‐induced organotellurium‐mediated radical polymerization to surface‐initiated graft polymerization. High graft densities were obtained, corresponding to reduced graft densities of about 0.32 and 0.42 for the PHEA and PPEGA brushes, respectively. These values were high enough to be categorized in the regime of “concentrated” polymer brushes (CPBs). Atomic force microscopic (AFM) study revealed that the CPB of PPEGA was allowed to be highly swollen in water but the CPB of PHEA did not. This means that water is reasonably good for PPEGA but not for PHEA. The AFM microtribological study between swollen brushes revealed two lubrication regimes, namely, boundary‐ and hydrodynamic‐lubrication regimes, with different shear‐velocity dependencies. Reflecting insufficient quality of water as a solvent, the CPB of PHEA showed adhesive interaction and thereby a higher frictional coefficient μ in the boundary lubrication. More interestingly, super lubrication was achieved for the CPB of PPEGA with a μ value in the order of 10^?4 in water and in 0.1 M aqueous NaCl solution (without the help of electrostatic repulsion). Super lubrication was concluded to be a characteristic feature of the CPB, even in an aqueous system. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Small-molecule inhibitors of the c-Fes protein-tyrosine kinase

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Highlights? Eight chemotypes block c-Fes kinase activity in vitro and in cell-based assays ? Potent inhibition of c-Fes by the anaplastic lymphoma kinase inhibitor TAE684 ? Solution of a c-Fes SH2-kinase crystal structure in complex with TAE684 ? Inhibitors reveal a role for c-Fes in osteoclast differentiation from macrophages     

Interaction between nonlinear diffusion and geometry of domain

Let Ω be a domain in ${\mathbb{R}}^N$, where $N?2$ and ?Ω is not necessarily bounded. We consider nonlinear diffusion equations of the form ${?}_{t}u=\mathrm{\Delta }?(u)$. Let $u=u(x,t)$ be the solution of either the initial-boundary value problem over Ω, where the initial value equals zero and the boundary value equals 1, or the Cauchy problem where the initial data is the characteristic function of the set ${\mathbb{R}}^N?\Omega$.We consider an open ball B in Ω whose closure intersects ?Ω only at one point, and we derive asymptotic estimates for the content of substance in B for short times in terms of geometry of Ω. Also, we obtain a characterization of the hyperplane involving a stationary level surface of u by using the sliding method due to Berestycki, Caffarelli, and Nirenberg. These results tell us about interactions between nonlinear diffusion and geometry of domain.     

Schrödinger uncertainty relation,Wigner–Yanase–Dyson skew information and metric adjusted correlation measure

In this paper, we give Schrödinger-type uncertainty relation using the Wigner–Yanase–Dyson skew information. In addition, we give Schrödinger-type uncertainty relation by use of a two-parameter extended correlation measure. We finally show a further generalization of Schrödinger-type uncertainty relation by use of the metric adjusted correlation measure. These results generalize our previous result in [Phys. Rev. A 82 (2010) 034101].     

Jacobi polynomials and associated reproducing kernel Hilbert spaces

This paper deals with a generating function of the Jacobi polynomials that satisfies the following properties (I) and (II). (I) The generating function is the kernel of an integral operator that is unitary. (II) The image of the unitary operator is a reproducing kernel Hilbert space of analytic functions and the reproducing kernel is given as a special value of the generating function above. A generating function that satisfies (I) is given in Watanabe (1998) [11]. The purpose of this paper is to give a generating function that satisfies (I) and (II). From a group theoretical point of view, a similar construction for zonal spherical functions is given in Watanabe (2006) [12].     

Three derivatives of 4‐fluoro‐5‐sulfonylisoquinoline

In 4‐fluoroisoquinoline‐5‐sulfonyl chloride, C₉H₅ClFNO₂S, (I), one of the two sulfonyl O atoms lies approximately on the isoquinoline plane as a result of minimizing the steric repulsion between the chlorosulfonyl group and the neighbouring F atom. In (S)‐(−)‐4‐fluoro‐N‐(1‐hydroxypropan‐2‐yl)isoquinoline‐5‐sulfonamide, C₁₂H₁₃FN₂O₃S, (II), there are two crystallographically independent molecules (Z′ = 2). The molecular conformations of these two molecules differ in that the amine group of one forms an intramolecular bifurcated hydrogen bond with the F and OH groups, whilst the other forms only a single intramolecular N—H...F hydrogen bond. The N—H...F hydrogen bonds correspond to weak coupling between the N(H) and ¹⁹F nuclei, observed in the ¹H NMR solution‐state spectra. In (S)‐(−)‐4‐[(4‐fluoroisoquinolin‐5‐yl)sulfonyl]‐3‐methyl‐1,4‐diazepan‐1‐ium chloride, C₁₅H₁₉FN₃O₂S⁺·Cl⁻, (III), the isoquinoline plane is slightly deformed, suggestive of a steric effect induced by the bulky substituent on the sulfonyl group.     

A computational characterization of N2@C60

Recent observations of N₂@C₆₀ are supported computationally. The geometry is optimized at the B3LYP/3-21G and PW91/3-21G levels. The lowest-energy structure has the N₂ unit oriented towards a pair of parallel pentagons so that the complex exhibits D_5d symmetry. Single-point energy calculations are further carried out at the B3LYP/6-31G*, PW91/6-31G* and MP2?=?FC/6-31G* levels and corrected for the basis set superposition error (BSSE). The MP2?=?FC/6-31G* treatment with the BSSE correction gives a stabilization energy of -9.3?kcal?mol^?1, whereas DFT approaches mostly fail to produce a stabilization. The entropy term for the encapsulation is also evaluated and leads to a standard Gibbs energy change upon encapsulation at room temperature of -3.3?kcal?mol^?1. The computed structural and vibrational characteristics are also reported.