Studies on the cellulose-binding domains adsorption to cellulose

Cellulose-binding domains (CBD) are modular peptides, present in many glycanases, which anchor these enzymes to the substrate. In this work, the effect of CBD adsorption on the surface properties of a model cellulose, Whatman CF11, was studied. The methods applied include inverse gas chromatography (IGC), ESCA, X-ray diffraction, and scanning electron microscopy (SEM). The CBD partition affinity (0.85 L/g) was calculated from adsorption isotherms. However, true adsorption equilibrium does not exist, since CBDs are apparently irreversibly adsorbed to the fibers. Both IGC and ESCA showed that fibers with adsorbed CBD have a lower acidic character and also a slightly higher affinity toward aliphatic molecules. This may however be a consequence of an increased surface area, a hypothesis that is supported by microscopic observations. The crystallinity index was not affected by CBD treatment.     

Optimal relaxation parameter for the Uzawa Method

Summary. We consider the Uzawa method to solve the stationary Stokes equations discretized with stable finite elements. An iteration step consists of a velocity update uⁿ⁺¹ involving the (augmented Lagrangian) operator ––÷ with 0, followed by the pressure update pⁿ⁺¹=pⁿ–div uⁿ⁺¹, the so-called Richardson update. We prove that the inf-sup constant satisfies 1 and that, if =1+^–1, the iteration converges linearly with a contraction factor ^2-1(2-) provided 0<<2. This yields the optimal value = regardless of .Mathematics Subject Classification (1991): 65N12, 65N15Partially supported by NSF Grant DMS-9971450Partially supported by NSF Grants DMS-9971450 and DMS-0204670Revised version received September 30, 2003     

An optimal Poincaré inequality in for convex domains

For convex domains with diameter we prove

for any with zero mean value on . We also show that the constant in this inequality is optimal.

     

Taming chaotic solitons in Frenkel-Kontorova chains by weak periodic excitations

We have proposed theoretically and confirmed numerically the possibility of controlling chaotic solitons in damped, driven Frenkel-Kontorova chains subjected to additive bounded noise by weak periodic excitations. Theoretically, we obtained an effective equation of motion governing the dynamics of the soliton center of mass for which we deduced Melnikov's method-based predictions concerning the regions in the control parameter space where homoclinic bifurcations are frustrated. Numerically, we found that such theoretical predictions can be reliably applied to the original Frenkel-Kontorova chains, even for the case of localized application of the soliton-taming excitations, and there is strikingly good agreement between analytical estimates and numerical results.     

Author Index

Authors Index

Author Index     

Simultaneous selection,amplification and isolation of a pseudo-peptide receptor by an immobilised N-methyl ammonium ion template

Immobilised N-methyl ammonium ions have been used to simultaneously select, amplify and isolate a pseudo-peptide receptor from a dynamic library of hydrazones.     

Inverse scattering for the nonlinear Schrödinger equation II. Reconstruction of the potential and the nonlinearity in the multidimensional case

We solve the inverse scattering problem for the nonlinear Schrödinger equation on :

We prove that the small-amplitude limit of the scattering operator uniquely determines . Our proof gives a method for the reconstruction of the potentials . The results of this paper extend our previous results for the problem on the line.

     

On the Riemann Hilbert type problems in Clifford analysis

In this paper boundary value problems combining Jump — Riemann and Hilbert problems for monogenic functions in Ahlfors-David regular surfaces and in the upper half space respectively are investigated. The explicit formula of the solution is obtained.     

Relativistic Calculations for Trapped Ions

We present recent results in the field of total binding energy calculations, Landщ factors, quantum electrodynamics corrections and lifetime that are of interest for ion traps and ion sources. We describe in detail MCDF and RMBPT calculation of ionic binding energies, which are needed for the determination of atomic masses from highly charged ion measurements. We also show new results concerning Landщ factor in 3-electron ions. Finally we describe how relativistic calculations can help understand the physics of heavy ion production ion sources. This revised version was published online in July 2006 with corrections to the Cover Date.