The prototype of an artificial molecular machine consisting of a trisammonium tricationic component interlocked with a tris(crown ether) component to form a molecular bundle with averaged C(3v) symmetry has been designed and synthesized. The system is based on noncovalent interactions, which include 1) N(+)-H...O hydrogen bonds; 2) C-H...O interactions between the CH(2)NH(2) (+)CH(2) protons on...

the complexation reactions between tl+ and pb2+ ions and crown ethers 12-crown-4(12c4), 15-crown-5 (15c5), benzo-15-crown-5 (b15c5), 18-crown-6 (18c6), dicyclohexyl-18-crown-6 (dc18c6) and aza-18-crown-6 (a18c6) were studied in 90% acetonitrile and 90% ethanol solutions at 25 °c, using an a.c. polarographic technique. the stoichiometry and stability of the complexes were determined by monitorin...

As it is well known, symmetry plays a crucial role in the theoretical physics. On other hand, the Noether symmetry is a useful procedure to select models motivated at a fundamental level, and to discover the exact solution to the given lagrangian. In this work, Noether symmetry in f(T) theory on a spatially homogeneous and anisotropic Bianchi type I universe is considered. We discuss the Lagran...

Background In most gymnosperms the cotyledons develop as a crown surrounding the incipient shoot apical meristem (SAM), which maintains the radial symmetry of the plant throughout embryogenesis. This is in contrast to the Arabidopsis embryo in which a symmetry-breaking event (from radial to bilateral symmetry) is associated with the emergence of the SAM and the two cotyledons [1]. We have previ...

The final hot strip profile is a superposition of the roll initial crown, the roll bending and flattening crown, the roll wearing crown and the roll thermal crown. In this research, linear regression models are proposed to predict the roll force, the roll wearing crown and the roll thermal crown using experimental data provided by Mobarake Steel Complex (MSC). The short beam theory based on ela...

Plasticity in crown architecture, contributing to leaf arrangement within crown, is an important feature for whole plant carbon assimilation and survival. In this study, I examined the plasticity in crown architecture to light condition and developmental stage by the changes in shoot production. Rhododendron reticulatum expands crown with orthotropic growth in monopodial branching in young stag...

A bstract Using topological string techniques, we compute BPS counting functions of 5d gauge theories which descend from 6d superconformal field upon circle compactification. Such are naturally organized in terms nodes Higgsing trees. We demonstrate that the specialization partition function as move crown to root a tree is determined by homomorphisms between rings Weyl invariant Jacobi forms. O...

The chief goal of full coronal restoration using preformed stainless steel crowns (SSC) is replication of normal crown form and function. Marginal adaptation of SSCs involves appropriate crown size selection, trimming the crown form to achieve proper length, crimping crown edges to proximate the prepared tooth, and finishing and polishing the crown form. This report about SSC restoration focuse...