TO THE EDITOR—How best to evaluate the effect of quaternary ammonium compound–based products after detection of postflood bacterial and fungal air bioburden remains uncertain. Thammasat University Hospital (Thailand) closed after severe black-water flooding in 2011; significant resources and costs were associated with hospital closure, reparations, and tiered reopening of select units [1]. In a...

A polyubiquitin comprises multiple covalently linked ubiquitins and recognizes myriad targets. Free or bound to ligands, polyubiquitins are found in different arrangements of ubiquitin subunits. To understand the structural basis for polyubiquitin quaternary plasticity and to explore the target recognition mechanism, we characterize the conformational space of Lys63-linked diubiquitin (K63-Ub2)...

Novel quaternary logic circuits, designed in 2-u.m'CMOS technology, are presented. These include threshold detector circuits with an improved output voltage swing and a simple binary-to-quaternary encoder circuit. Based on these, the literal circuits, the quaternary-tobinary decoder, and the quaternary register designs are derived. A novel scheme for improving the power-delay product of pseudo-...

The Quaternary has been described as an important time for genetic diversification and speciation. This is based on the premise that Quaternary climatic conditions fostered the isolation of populations and, in some instances, allopatric speciation. However, the 'Quaternary Ice-Age speciation model' rests on two key assumptions: (i) that biotic responses to climate change during the Quaternary w...

An in situ IR technique was applied in the selective synthesis of the key intermediate for rapamycin derivatives, which made the reaction endpoint easily defined. This technology solved a bothersome problem in the preparation of rapamycin derivatives, and based on this technique, the 31-OH and 42-OH of rapamycin were chemically modified by a series of quaternary ammonium salts to generate 11 co...

In this paper, a new construction of quaternary bent functions from quaternary quadratic forms over Galois rings of characteristic 4 is proposed. Based on this construction, several new classes of quaternary bent functions are obtained, and as a consequence, several new classes of quadratic binary bent and semi-bent functions in polynomial forms are derived. This work generalizes the recent wor...

The periodicity of the genus sequences of the heaps of finite quaternary games are examined. While the truncated genus sequence of the heaps of finite quaternary games becomes periodic, this is not true for the genus sequence in general. This contrasts with the known result that the genus sequence of the heaps of all finite subtraction games, a subset of finite quaternary games, becomes periodic.

We report synthesis of surface-active quaternary amino polyfluorosiloxanes. Hydrosilation of silanic hydrogen containing polyfluorosiloxanes with olefinic epoxides, in the presence of a platinum–divinyltetramethyldisiloxane complex gave epoxy polyfluorosiloxanes. These, on further reaction with various amines followed by quaternization, gave quaternary amino polyfluorosiloxanes. The quaternary ...