Laser addressed thermo-optic effect in a novel dyed liquid-crystalline polysiloxane

Initial experimental evaluation of a novel liquid-crystalline polysiloxane for thermo-optical recording is presented. A versatile system using a single laser source has been used to gather information on the dynamics of laser addressing. To ensure the most stable, highest-contrast pixel the polymer must be heated through its biphasic region and some way into the isotropic phase. It was found that at 60°C using laser pulses of 300μs or less, write-in and selective erasure times were on the submillisecond timescale, and that bulk erasure required 1-2 min. The use of the polymer in an analogue optical store has been demonstrated and an unoptimized sensitivity of 12nJ/μm² for 632°8 nm light was found at 24°C.     

Mass spectra of some tropane and tropidine derivatives

Fragmentation patterns of tropane and tropidine derivatives have been shown to depend on the nature of the substituents. Unsaturation in the 6-membered ring leads to preferential fragmentation of the two carbon bridge. When the 6-membered ring is saturated and substituted with poor leaving groups (OH and CN) fragmentation of the 6-membered ring is preferred.     

Coupling semiconductor nanocrystals to a fused-silica microsphere: a quantum-dot microcavity with extremely high Q factors

We demonstrate a quantum-dot microcavity by coupling core-shell semiconductor nanocrystals to a fused-silica microsphere. We show that the composite microcavity can feature Q factors of the order of 10(8), providing a model system for investigating cavity QED and microlasers at the level of single quantum dots.     

Diastereo- and Enantioselective 1,4-Difunctionalization of Borylenynes by Catalytic Conjunctive Cross-Coupling

Enantioselective conjunctive cross-coupling of enyne-derived boronate complexes occurs with 1,4 addition of the electrophile and migrating group across the π system. This reaction pathway furnishes α-boryl allenes as the reaction product. In the presence of a chiral catalyst, both the central and axial chirality of the product can be controlled during product formation.     

Clifford semigroups as functors and their cohomology

We prove that the category of Clifford semigroups and prehomomorphisms CSP\mathcal{CSP} is isomorphic to a certain subcategory of the category of diagrams over groups. Under this isomorphism, Clifford semigroups are identified with certain functors. As an application of the isomorphism theorem, we show that the category with objects commutative inverse semigroups having the same semilattice of idempotents and with morphisms, the inverse semigroup homomorphisms that fix the semilattice, imbeds into a category of right modules over a certain ring. Also we find a very close relationship between the cohomology groups of a commutative inverse monoid and the cohomology groups of the colimit group of the functor giving the monoid.     

Investigation of the one-pot synthesis of quinolin-2-(1H)-ones and the discovery of a variation of the three-component Ugi reaction

Rapid access to the quinolin-2-(1H)-one scaffold is afforded by a sequential 4 component Ugi–Knoevenagel condensation of an aminophenylketone, an aromatic aldehyde possessing electron donating moieties, cyanoacetic acid and an aliphatic isocyanide, in moderate to good yields (49–71%). Interestingly, when the reaction is performed using aromatic aldehydes bearing electron withdrawing moieties or isocyanides containing aromatic or ester units, a mixture of a quinolin-2-(1H)-one and an α-amino amide (Ugi three-component adduct) is afforded in varying ratios. Further when the reaction is performed utilizing a combination of an isocyanide-containing aromatic or carbonyl unit, and an aldehyde possessing an electron withdrawing functionality, the Ugi three-component adduct is exclusively afforded. In our hands this new variation of the Ugi 3CR proved to be efficient and robust affording analogues in good yields (51–70%).     

Bilirubin Oxidase‐Based Nanobiocathode Working in Serum‐Mimic Buffer for Implantable Biofuel Cell

Low‐density graphite electrodes have been covalently modified with gold nanoparticles and used as scaffold for the oriented immobilization of Myrothecium verrucaria bilirubin oxidase. The developed nanobioelectrodes have been tested as a biocathode in a human‐serum surrogate buffer that mimics physiological conditions. The nanostructured bioelectrode offered a ?140 µA cm^?2 current density under serum‐mimic conditions at 0.2 V, and was operational during at least 6 days.     

Poly(Ethylene Glycol-block-2-Ethyl-2-Oxazoline) as Cathode Binder in Lithium-Sulfur Batteries

Functional binders constitute a strategy to overcome several challenges that lithium-sulfur (Li-S) batteries are facing due to soluble reaction intermediates in the positive electrode. Poly (ethylene oxide) (PEO) and poly (vinylpyrrolidone) (PVP) are in this context a previously well-explored binder mixture. Their ether and amide groups possess affinity to the dissolved sulfur species, which enhances the sulfur utilization and mitigates the parasitic redox shuttle. However, the immiscibility of PEO and PVP is a concern for electrode stability. Copolymers comprising ether and amide groups are thus promising candidates to improve the stability the system. Here, a series of poly (ethylene glycol-block-2-ethyl-2-oxazoline) with various block lengths is synthesized and explored as binders in S/C composite electrodes in Li-S cells. While the electrochemical analyses show that although the sulfur utilization and capacity retention of the tested electrodes are similar, the integrity of the as-cast electrodes can play a key role for power capability.