If ∗ : G → G is an involution on the finite group G, then ∗ extends to an involution on the integral group ring Z[G]. In this paper, we consider whether bicyclic units u ∈ Z[G] exist with the property that the group 〈u, u∗〉, generated by u and u∗, is free on the two generators. If this occurs, we say that (u, u∗) is a free bicyclic pair. It turns out that the existence of u depends strongly upo...

Many biologically active peptides found in nature exhibit a bicyclic structure wherein a head-to-tail cyclic backbone is further constrained by an intramolecular linkage connecting two side chains of the peptide. Accordingly, methods to access macrocyclic peptides sharing this overall topology could be of significant value toward the discovery of new functional entities and bioactive compounds....

Glutamine synthetase (GS) regulation in Escherichia coli by reversible covalent modification cycles is a prototype of signal transduction by enzyme cascades. Such enzyme cascades are known to exhibit ultrasensitive response to primary stimuli and act as signal integration systems. Here, we have quantified GS bicyclic cascade based on steady state analysis by evaluating Hill coefficient. We demo...

The microbial degradation pathways of bicyclic monoterpenes contain unknown enzymes for carbon-carbon cleavages. Such enzymes may also be present in the betaproteobacterium Castellaniella defragrans, a model organism to study the anaerobic monoterpene degradation. In this study, a deletion mutant strain missing the first enzyme of the monocyclic monoterpene pathway transformed cometabolically t...

The title compound, C9H12O5, is a bicyclic lactone, presenting a 2,6-dioxabi-cyclo-[3.3.0]octan-3-one skeleton, which was obtained through an intra-molecular lactonization. The bicyclic lactone presents a cis ring-junction and a 1,5-trans-substituted tetra-hydro-furan. Both five-membered rings are in twisted envelope conformations with one of the fused C atoms as the flap. The dihedral angle be...

We study algebraic and topological properties of topological semigroups containing a copy of the bicyclic semigroup C(p, q). We prove that each topological semigroup S with pseudocompact square contains no dense copy of C(p, q). On the other hand, we construct a consistent example of a Tychonov countably compact semigroup containing a copy of C(p, q). In this paper we study the structural prope...

Novel bicyclic iminosugar derivatives fused thiazolidin-4-one were conveniently synthesized by double Pummerer rearrangements, and their HIV reverse transcriptase (RT) inhibitory activities were preliminary examined. The notable anti-HIV-RT activity demonstrated that such bicyclic azasugars hold potential as a new kind of HIV-RT inhibitors.

the first ($pi_1$) and the second $(pi_2$) multiplicative zagreb indices of a connected graph $g$, with vertex set $v(g)$ and edge set $e(g)$, are defined as $pi_1(g) = prod_{u in v(g)} {d_u}^2$ and $pi_2(g) = prod_{uv in e(g)} {d_u}d_{v}$, respectively, where ${d_u}$ denotes the degree of the vertex $u$. in this paper we present a simple approach to order these indices for connected graphs on ...

A directed triple system of order v, denoted DTS(v), is said to be f-bicyclic if it admits an automorphism consisting of f fixed points and two disjoint cycles. In this paper, we give necessary and sufficient conditions for the existence of f-bicyclic

Bridgehead bicyclic unsaturated enamines were prepared by a tandem rhodium-catalyzed C-H bondactivation/alkenylation/electrocyclization of alkyne-tethered unsaturated imines. These strained bicyclic enamines exhibitunique reactivity: for example, they give N-Alkylated products upon treatment with alkylating reagents and undergo doublebond isomerization to alleviate ring strain upon ...