Photochemistry of homoconjugated ketones: 2-(carbomethoxy)spiro[5.5]undeca-1, 3-dien-7-one.

The direct and sensitized irradiation of the title compound ($\text{2}$c) was studied with particular attention to its oxa-di-π-methane rearrangement, the product of which is of notable structural and synthetic interest. X-ray diffraction data of the final product (8) are given to support structural assignments.     

Two-settlement electricity markets with price caps and Cournot generation firms

We compare two alternative mechanisms for capping prices in two-settlement electricity markets. With sufficient lead time, forward market prices are implicitly capped by competitive pressure of potential entry that will occur when forward prices rise above some backstop price. Another more direct approach is to cap spot prices through a regulatory intervention. In this paper we explore the implications of these two alternative mechanisms in a two-settlement Cournot equilibrium framework. We formulate the market equilibrium as a stochastic equilibrium problem with equilibrium constraints (EPEC) capturing congestion effects, probabilistic contingencies and horizontal market power. As an illustrative test case, we use the 53-bus Belgian electricity network with representative generator costs but hypothetical demand and ownership structure. Compared to a price-uncapped two-settlement system, a forward cap increases firms’ incentives for forward contracting, whereas a spot cap reduces such incentives. Moreover, in both cases, more forward contracts are committed as the generation resource ownership structure becomes more diversified.     

Templating nanostructures by mesoporous materials with an emphasis on room temperature and cryogenic TEM studies

Rapid strides realized in the field of ordered mesoporous silica (OMS) with a well-defined pore shape and nanometric sizes, provide new gateways for the preparation of nanostructured materials having controlled shape and size with a very narrow distribution. The focus of the current review is on the synthesis of nanostructures templated by OMS either in bulk or in thin film form. The importance of electron microscopy as an indispensable technique in the structural characterization of OMS templated nanostructures, including cryo-TEM, electron tomography and HR-SEM, is highlighted in this review.     

A conjugate directions method for subjective assessment of normal distributions

A procedure is developed that enables the encoding of a subjectiven-dimensional joint normal probability density function through the assessment of its marginal means and variances andn(n–1)/2 conditional means. The new method is based on the theory of conjugate directions for quadratic forms, and it exploits the fact that normal distributions have quadratic equal-likelihood surfaces. Unlike previous approaches, this new method enables easy detection and resolution of inconsistencies in the assessments that could lead to an indefinite estimate of the covariance matrix.     

High Affinity Recognition of a Selected Amino Acid Epitope within a Protein by Cucurbit[8]uril Complexation

Supramolecular interactions between the host cucurbit[8]uril (CB[8]) and amino acids have been widely interrogated, but recognition of specific motifs within a protein domain have never been reported. A phage display approach was herein used to select motifs with the highest binding affinity for the heteroternary complex with methyl viologen and CB[8] (MV?CB[8]) within a vast pool of cyclic peptide sequences. From the selected motifs, an epitope consisting of three amino acid was extrapolated and incorporated into a solvent‐exposed loop of a protein domain; the protein exhibited micromolar binding affinity for the MV?CB[8] complex, matching that of the cyclic peptide. By achieving selective CB[8]‐mediated conjugation of a small molecule to a recombinant protein scaffold we pave the way to biomedical applications of this simple ternary system.     

Effect of molecular conformations on the adsorption behavior of gold-binding peptides

Despite extensive recent reports on combinatorially selected inorganic-binding peptides and their bionanotechnological utility as synthesizers and molecular linkers, there is still only limited knowledge about the molecular mechanisms of peptide binding to solid surfaces. There is, therefore, much work that needs to be carried out in terms of both the fundamentals of solid-binding kinetics of peptides and the effects of peptide primary and secondary structures on their recognition and binding to solid materials. Here we discuss the effects of constraints imposed on FliTrx-selected gold-binding peptide molecular structures upon their quantitative gold-binding affinity. We first selected two novel gold-binding peptide (AuBP) sequences using a FliTrx random peptide display library. These were, then, synthesized in two different forms: cyclic (c), reproducing the original FliTrx gold-binding sequence as displayed on bacterial cells, and linear (l) dodecapeptide gold-binding sequences. All four gold-binding peptides were then analyzed for their adsorption behavior using surface plasmon resonance spectroscopy. The peptides exhibit a range of binding affinities to and adsorption kinetics on gold surfaces, with the equilibrium constant, Keq, varying from 2.5x10(6) to 13.5x10(6) M(-1). Both circular dichroism and molecular mechanics/energy minimization studies reveal that each of the four peptides has various degrees of random coil and polyproline type II molecular conformations in solution. We found that AuBP1 retained its molecular conformation in both the c- and l-forms, and this is reflected in having similar adsorption behavior. On the other hand, the c- and l-forms of AuBP2 have different molecular structures, leading to differences in their gold-binding affinities.     

Ionic liquids as novel guests for cucurbit[6]uril in neutral water

Cucurbit[6]uril was dissolved through encapsulation of an imidazolium-based ionic liquid guest in a pure water environment and the dissolution ability could be tuned by augmenting the imidazolium structure.     

Surface‐Bound Cucurbit[8]uril Catenanes on Magnetic Nanoparticles Exhibiting Molecular Recognition

We demonstrate the preparation of surface‐bound cucurbit[8]uril (CB[8]) catenanes on silica nanoparticles (NPs), where CB[8] was employed as a tethered supramolecular “handcuff” to selectively capture target guest molecules. In this catenane, CB[8] was threaded onto a methyl viologen (MV²⁺) axle and immobilized onto silica NPs. The formation of CB[8] catenanes on NPs were confirmed by UV/Vis titration experiments and lithographic characterization, demonstrating a high density of CB[8] on the silica NPs surface, 0.56 nm^?2. This CB[8] catenane system exhibits specific molecular recognition towards certain aromatic molecules such as perylene bis(diimide), naphthol and aromatic amino acids, and thus it can act as a nanoscale molecular receptor for target guests. Furthermore, we also demonstrate its use as an efficient and recyclable nano‐platform for peptide separation. By embedding magnetic NPs inside silica NPs, separation could be achieved by simply applying an external magnetic field. Moreover, the peptides captured by the catenanes could be released by reversible single‐electron reduction of MV²⁺. The entire process demonstrated high recoverability.     

<Emphasis Type="Italic">M</Emphasis>-slenderness

Analogues of Nunke’s theorem are proved which characterize variants of slenderness. For a bounded monotone subgroup M of ? ^ω , a torsion-free reduced abelian group G is M-slender if, and only if, there is no monomorphism from M into G. It is consistent relative to ordinary set theory (ZFC) that if M ≠ ? ^ω is an unbounded monotone subgroup of ? ^ω , then a torsion-free reduced abelian group G is M-slender if, and only if, there is no monomorphism from M into G.     

X-ray structure and DFT study of C1-C60(CF3)12. A high-energy, kinetically-stable isomer prepared at 500 degrees C

The title compound, prepared from C(60) and CF(3)I at 500 degrees C, exhibits an unusual fullerene(X)12 addition pattern that is 40 kJ mol(-1) less stable than the previously reported C(60)(CF(3))12 isomer.