Synthesis of Functional Polymers by Post‐Polymerization Modification

Post‐polymerization modification is based on the direct polymerization or copolymerization of monomers bearing chemoselective handles that are inert towards the polymerization conditions but can be quantitatively converted in a subsequent step into a broad range of other functional groups. The success of this method is based on the excellent conversions achievable under mild conditions, the excellent functional‐group tolerance, and the orthogonality of the post‐polymerization modification reactions. This Review surveys different classes of reactive polymer precursors bearing chemoselective handles and discusses issues related to the preparation of these reactive polymers by direct polymerization of appropriately functionalized monomers as well as the post‐polymerization modification of these precursors into functional polymers.     

The Order Completion Method for Systems of Nonlinear PDEs Revisited

In this paper we presents further developments regarding the enrichment of the basic Theory of Order Completion as presented in Oberguggenberger and Rosinger (Solution of continuous nonlinear PDEs through order completion, North-Holland, Amsterdam, 1994). In particular, spaces of generalized functions are constructed that contain generalized solutions to a large class of systems of continuous, nonlinear PDEs. In terms of the existence and uniqueness results previously obtained for such systems of equations (van der Walt, Acta Appl. Math. 103:1–17, 2008), one may interpret the existence of generalized solutions presented here as a regularity result. Furthermore, it is indicated how the methods developed in this paper may be adapted to solve initial and/or boundary value problems. In particular, we consider the Navier-Stokes equations in three spacial dimensions, subject to an initial condition on the velocity. In this regard, we obtain the existence of a generalized solution to a large class of such initial value problems.      

Consistency of the preoperative and intraoperative diagnosis of benign vocal fold lesions

The purpose of this retrospective study was to compare the preoperative and intraoperative diagnosis of benign vocal fold lesions for consistency. The diagnosis was made in 221 consecutive patients with benign vocal fold lesions for which a microlaryngoscopy was carried out in a general ENT-clinic. The preoperative diagnosis was obtained by both white halogen and stroboscopic light. The intraoperative diagnosis was obtained by direct microscopic visualization and palpation of the vocal folds. In 36% of the patients, the preoperative diagnosis was changed intraoperatively. In 31% of the patients, a lesion was missed at the preoperative examination and a lesion was diagnosed only during microlaryngoscopy. Bilateral lesions were found in 53% of the patients preoperatively, and in 82% of the patients intraoperatively. Specially intracordal lesions constituted a diagnostic pitfall. Because the preoperative and intraoperative diagnosis often differed, both the patients and the ENT-surgeon must keep an open mind about what may need to be done at surgery.     

Additive decomposition of matrices under rank conditions and zero pattern constraints

Czechoslovak Mathematical Journal - This paper deals with additive decompositions A = A1 + … + Ap of a given matrix A, where the ranks of the summands A1, …, Ap are prescribed and meet...     

Mumford coverings of the projective line

A Mumford covering of the projective line over a complete non-archimedean valued field K is a Galois covering X? P¹_K X\rightarrow {\bf P}^1_K such that X is a Mumford curve over K. The question which finite groups do occur as Galois group is answered in this paper. This result is extended to the case where P¹_K {\bf P}^1_K is replaced by any Mumford curve over K.     

Imaging of dynamic processes on surfaces by light

This work focuses on imaging of dynamic processes on surfaces, using light to illuminate the area of interest. The methods discussed here are those in which the photoelectrons emitted from or the light reflected off the surface are measured. While the first approach is well-known since electron microscopy was invented and has been used in surface science applications for a decade, genuine optical microscope methods using polarized light were first developed in 1995 for imaging surface reactions.

The results discussed here are from different fields of surface research. These include the imaging of adsorption phenomena, surface diffusion and growth processes. The main emphasis will be on pattern formation of surface reactions under strictly controlled parameters. The most recent techniques expand the range of observable pressure conditions by many orders of magnitude, thus bridging the pressure gap in imaging surface reactions.     

Structure,insertion electrochemistry,and magnetic properties of a new type of substitutional solid solutions of copper,nickel, and iron hexacyanoferrates/hexacyanocobaltates

Substitutional solid solutions of metal hexacyanometalates in which low-spin iron(III) and cobalt(III) ions populate the carbon-coordinated sites were synthesized and studied by powder diffraction including Rietveld refinement, cyclic voltammetry of immobilized microparticles, diffuse reflection vis-spectrometry, and magnetization techniques. The continuous solid solution series of potassium copper(II), potassium nickel(II), and iron(III) [(hexacyanoferrate(III))(1-x)(hexacyanocobaltate(III))(x)] show that the substitution of low-spin iron(III) by cobalt(III) in the hexacyanometalate units more strongly affects the formal potentials of the nitrogen-coordinated copper(II) and high-spin iron(III) ions than those of the remaining low-spin iron(III) ions. In the case of copper(II) and iron(III) [(hexacyanoferrate(III))(1-x)(hexacyanocobaltate(III))(x)] the peak currents decrease much more than can be explained by stoichiometry, indicating that the charge propagation is slowed by the substitution of low-spin iron(III) by cobalt(III). The Rietveld refinement of all compounds confirmed the structure initially proposed by Keggin for Prussian blue and contradicts the structure described later by Ludi. The dependencies of lattice parameters on composition exhibit in all series of solid solutions studied similar, although small, deviations from ideality, which correlate with the electrochemical behavior. Finally, a series of solid solutions of the composition KNi(0.5)(II)Cu(0.5)(II)[Fe(III)(CN)(6)](1-x)[Co(III)(CN)(6)](x), where both the nitrogen- and carbon-coordinated metal ions are mixed populated and were synthesized and characterized. These are the first examples of solid solutions of metal hexacyanometalates with four different metal ions, where both the nitrogen- and the carbon-coordinated sites possess a mixed population.     

THE ROLE OF HOST-CELL REPAIR IN LIQUID-HOLDING RECOVERY OF U.V.-IRRADIATED ESCHERICHIA COLI

Abstract— The experiments reported give evidence that liquid-holding recovery (LHR) of u.v. irradiated E. coli cells involves basically the same type of dark repair which causes reactivation of phage and which results in much increased survival of the cells themselves [host-cell reactivation (HCR)]. LHR is very small in the two HCR(-) strains B syn^- and B_s-1, but occurs to larger but different extents in the three HCR(+) strains B, B/r, and B/r (Λ). LHR is inhibited if the liquid contains caffeine or acriflavine, both of which are known to inhibit HCR. The results indicate that most of the LHR effect, if not all, occurs during the liquid holding, rather than under growth conditions after liquid holding. It is assumed that the holding itself allows a prolonged time for, and therefore an enhancement of, HCR. It is thus implicit that LHR can be observed only where otherwise HCR of repairable u.v. damage would be incomplete, and that different extents of LHR, as observed in the three HCR(+) strains, reflect different extents of incompleteness of HCR. It is concluded that the repairable u.v. hits which are not fully repaired by HCR are predominantly those concerned with the extra u.v. sensitivity of the strains B and B/r (Λ), relative to B/r.