A multiple flux boundary element method applied to the description of surface water waves

This paper concerns a two dimensional numerical model based on a high-order boundary element method with fully nonlinear free surface boundary conditions. Multiple fluxes are applied as a method of removing the so-called “corner problem”, whereby the direction of the outward normal at geometric discontinuities is ill-defined. In the present method, both fluxes associated with differing directions of the outward normal at a corner are considered, allowing a single node to be placed at that position. This prevents any loss of information at what can be an important part of the boundary, especially if considering simulations of wave reflection and wave run-up. The method is compared to both the double node approach and the use of discontinuous elements and is shown to be a more accurate technique. The success of the method is further demonstrated by its ability to accurately simulate various problems involving wave transmission and wave-structure interactions at domain corners; the results being achieved without the need for filtering, smoothing or re-gridding of any kind.     

Two‐Step Functionalization of Oligosaccharides Using Glycosyl Iodide and Trimethylene Oxide and Its Applications to Multivalent Glycoconjugates

Oligosaccharide conjugates, such as glycoproteins and glycolipids, are potential chemotherapeutics and also serve as useful tools for understanding the biological roles of carbohydrates. With many modern isolation and synthetic technologies providing access to a wide variety of free sugars, there is increasing need for general methodologies for carbohydrate functionalization. Herein, we report a two‐step methodology for the conjugation of per‐O‐acetylated oligosaccharides to functionalized linkers that can be used for various displays. Oligosaccharides obtained from both synthetic and commercial sources were converted to glycosyl iodides and activated with I₂ to form reactive donors that were subsequently trapped with trimethylene oxide to form iodopropyl conjugates in a single step. The terminal iodide served as a chemical handle for further modification. Conversion into the corresponding azide followed by copper‐catalyzed azide–alkyne cycloaddition afforded multivalent glycoconjugates of Gb3 for further investigation as anti‐cancer therapeutics.     

Lipid bilayer assembly at a gold nanocavity array

The assembly of lipid bilayer membranes, using ultrasonic disruption of liposomes of L-α-Dimyristoyl phosphatidylcholine, across 820 nm diameter spherical cap gold cavity arrays is demonstrated.     

Raman analysis of perrhenate and pertechnetate in alkali salts and borosilicate glasses

Sodium borosilicate glasses containing rhenium or technetium were fabricated and their vibrational spectra studied using confocal Raman microscopy. Glass spectra were interpreted relative to new high‐resolution spectra of pure crystalline NaReO₄, KReO₄, NaTcO₄, and KTcO₄ salts. Spectra of perrhenate and pertechnetate glasses exhibited sharp Raman bands, characteristic of crystalline salt species, superimposed on spectral features of the borosilicate matrix. At low concentrations of added KReO₄ or KTcO_4, the characteristic pertechnetate and perrhenate features are weak, whereas at high additions, sharp peaks from crystal field‐splitting and C_4h symmetry dominate glass spectra, clearly indicating ReO₄⁻ or TcO₄⁻ is locally coordinated with K and/or Na. Peaks indicative of both K and Na salts are evident in many Raman spectra, with the Na form being favored at high concentrations of the source chemicals, where more K⁺ is available for ion exchange with Na⁺ from the base glass. The observed ion exchange likely occurred within depolymerized channels where nonbridging oxygens create segregation from the glass network in regions containing anions such as ReO₄⁻ and TcO₄⁻ as well as excess alkali cations. Although this anion exchange provides evidence of chemical mixing in the glass, it does not prove the added salts were homogeneously incorporated in the glass. The susceptibility to ion exchange from the base glass indicates that long‐term immobilization of Tc in borosilicate glass must account for excess charge compensating alkali cations in melt glass formulations. Published 2014. This article is a U. S. Government work and is in the public domain in the USA.     

A focused approach to combining logics

We present a compact sequent calculus LKU for classical logic organized around the concept of polarization. Focused sequent calculi for classical, intuitionistic, and multiplicative-additive linear logics are derived as fragments of the host system by varying the sensitivity of specialized structural rules to polarity information. We identify a general set of criteria under which cut-elimination holds in such fragments. From cut-elimination we derive a unified proof of the completeness of focusing. Furthermore, each sublogic can interact with other fragments through cut. We examine certain circumstances, for example, in which a classical lemma can be used in an intuitionistic proof while preserving intuitionistic provability. We also examine the possibility of defining classical-linear hybrid logics.     

Many-electron effects in the XPS spectra of Cu and Ag

The L and M XPS spectra of Cu (Z = 29) and the M and N spectra of Ag (Z = 47) are measured. The lineshift and the line-width of the L, M, and N core levels are analysed in a systematic way from the viewpoint of dynamic decay processes and fluctuations of a hole. The non-relativistic diagrammatic many-body calculations give much better agreement with the measured linewidths than the conventional methods because of a consistent treatment of correlation and localization effects.     

Fluorophore-assisted carbohydrate electrophoresis in the separation, analysis, and sequencing of carbohydrates

Carbohydrate analysis has traditionally been viewed as a specialty science, performed only in a few well-established laboratories using conventional carbohydrate analysis technology (e.g. NMR, gas chromatography-mass spectroscopy, high-performance liquid chromatography, capillary electrophoresis) combined with the specialized technical training that has been essential for accurate interpretation of the data. This tradition of specialized laboratories is changing, due primarily to an increase in the number of scientists performing routine carbohydrate analysis. As a result, many scientists who are not trained in traditional carbohydrate analytical techniques now need to be able to perform accurate carbohydrate analysis in their own laboratories. This has created a need for technically simple and inexpensive methods of carbohydrate analysis. In this review, we present application vignettes of a technically simple, yet analytically powerful method called fluorophore-assisted carbohydrate electrophoresis (FACE). FACE can be used for performing routine oligosaccharide profiling, monosaccharide analysis, and sequencing of a variety of carbohydrates.