Tetrapeptides of primary sequence Tyr-X-Phe-YNH2, where X is D-Cys or D-Pen (penicillamine) and where Y is D-Pen or L-Pen, were prepared and were cyclized via the side chain sulfurs of residues 2 and 4 to disulfide or dithioether-containing analogs. These peptides are related to previously reported penicillamine-containing pentapeptide enkephalin analogs but lack the central glycine residue of ...

Motivated by recent works on the genus of classifying spaces of compact Lie groups, here we study the set of filtered λ-ring structures over a filtered ring from a purely algebraic point of view. From a global perspective, we first show that this set has a canonical topology compatible with the filtration on the given filtered ring. For power series rings R[[x]], where R is between Z and Q, wit...

Motivated in part by recent works on the genus of classifying spaces of compact Lie groups, here we study the set of filtered λ-ring structures over a filtered ring from a purely algebraic point of view. From a global perspective, we first show that this set has a canonical topology compatible with the filtration on the given filtered ring. For power series rings R[[x]], where R is between Z an...

Abstract We show that the image of a subshift X under various injective morphisms symbolic algebraic varieties over monoid universes with variety alphabets is finite type, respectively sofic subshift, if and only so . Similarly, let G be countable A , B Artinian modules ring. prove for every closed submodule $\Sigma \subset A^G$ -equivariant uniformly continuous module homomorphism $\tau \colon...

Five commercially available encryption packages for the IBM PC are described and broken.

Let $mathfrak{A}$ be an algebra. A linear mapping $delta:mathfrak{A}tomathfrak{A}$ is called a textit{derivation} if $delta(ab)=delta(a)b+adelta(b)$ for each $a,binmathfrak{A}$. Given two derivations $delta$ and $delta'$ on a $C^*$-algebra $mathfrak A$, we prove that there exists a derivation $Delta$ on $mathfrak A$ such that $deltadelta'=Delta^2$ if and only if either $delta'=0$ or $delta=sdel...

In this paper we examine a certain filtration on topological Hochschild homology. This filtration has the virtue that it respects the cyclic structure of topological Hochschild homology, and therefore it is compatible with the cyclotomic structure used to define topological cyclic homology. As an example we show how the skeleton filtration of a simplicial ring gives rise to spectral sequences s...

Heartwood extractives (nonstructural wood components) are believed to be formed from a combination of compounds present in the adjacent sapwood and materials imported from the phloem. The roles of local compounds and imported material in heartwood formation could have important implications for the wood quality of species having naturally durable wood. Stable isotope composition (delta(13)C) wa...

For a field F of characteristic different from 2, containing a square root of -1, endowed with an F-compatible valuation v such that the residue field has at most two square classes, we use a combinatorial analogue of the Witt ring of F to prove that an anisotropic quadratic form over F with even dimension d, trivial discriminant and Hasse-Witt invariant can be written in the Witt ring as the s...

The paper discusses the development of an IBM PC based tool, for calculating train braking distances for various train classes on a rail network. There is discussion on current industry practice and the limitations of that practice, the concept of the tool itself, including the assumptions made, the strategy adopted to minimise the risk of incorrect calculations, and the results of adopting tha...