Academic literature on the topic 'Molecular switching elements'

Abstract In conservative site-specific recombination, DNA molecules are broken in both strands at two separate predetermined points, and the ends are rejoined to new partners, without any synthesis or degradation of the DNA (Fig. la). The reactions are catalysed by specialized recombinase proteins and may involve other protein accessory factors. Many site-specific recombination systems have been identified in prokaryotes and eukaryotes, and several systems have been reconstituted in vitro. In studying these systems, one of the main aims has been to attempt to understand the mechanisms by which selectivity for recombination between sites in particular relationships is achieved. It has become apparent that DNA topology plays a crucial role in this selectivity. In vivo, site-specific recombination has a variety of functions, including switching of gene expression, control of plasmid copy number, resolution of plasmid multimers to monomers, bacteriophage integration and excision, and transposon co-integrate resolution.

Substitutionally inert ruthenium complexes bearing benzimidazole derivatives have unique electrochemical and photochemical properties. In particular, proton coupled electron transfer (PCET) in ruthenium–benzimidazole complexes leads to rich redox chemistry, which allows e.g. the tuning of redox potentials or switching by deprotonation. Using the background knowledge from acquired from their solution-state chemistry, Ru complexes immobilized on electrode surfaces have been developed and these offer new research directions toward functional molecular devices. The integration of surface-immobilized redox-active Ru complexes with multilayer assemblies via the layer-by-layer (LbL) metal coordination method on ITO electrodes provides new types of functionality. To control the molecular orientation of the complexes on the ITO surface, free-standing tetrapodal phosphonic acid anchor groups were incorporated into tridentate 2,6-bis(benzimidazole-2-yl)pyridine or benzene ligands. The use of the LbL layer growth method also enables “coordination programming” to fabricate multilayered films, as a variety of Ru complexes with different redox potentials and pKa values are available for incorporation into homo- and heterolayer films. Based on this strategy, many functional devices, such as scalable redox capacitors for energy storage, photo-responsive memory devices, proton rocking-chair-type redox capacitors, and protonic memristor devices have been successfully fabricated. Further applications of anchored Ru complexes in photoredox catalysis and dye-sensitized solar cells may be possible. Therefore, surface-confined Ru complexes exhibit great potential to contribute to the development of advanced functional molecular devices.

From the starting point of mW-power infrared-driven digital optical logic elements working from nonlinearity of electronic origin, simple 2-element circuits were demonstrated with the capability of sub-microsecond cycle rates but with difficulties in fabrication of parallel arrays. Current work has therefore concentrated on devices made with thin-film coating techniques in which both conventional thermal evaporation and molecular beam deposited layers have been used. At comparable device diameter, operating powers are typically a few milliwatts, similar to the infrared electronic case. The ear

Conventional kinesin is a dimeric motor protein that uses adenosine triphosphate (ATP) to walk processively along the microtubule. Although its nucleotide dependent conformational switching and binding of the neck linker (NL) on the motor head are known to be key events in kinesin motility, the basic mechanism by which it amplifies a small conformational change upon ATP binding to generate the force of the walking stroke has not been known. We combined structural analysis with a set of molecular dynamics simulations to identify the 9-residue long N-terminal region, which we named the ‘cover st

Abstract The ORBIT rising stem ball valve is a proven technology for use in applications where zero leakage and frequent cycling operations are demanded. The valve uses a tilt-and-turn design, which eliminates rubbing between sealing surfaces, ensuring reliable, extended-life performance in critical and demanding shutoff applications such as switching valves in molecular sieve systems, high-pressure hydrogenation, and hot oil. Within these applications, a single valve failure can lead to significant downtime, production losses, and unforeseen costs for the end user. Traditionally, maintenance