Time-reversal symmetry relations for currents in quantum and stochastic nonequilibrium systems

An overview is given of recent advances in the nonequilibrium statistical mechanics of quantum systems and, especially, of time-reversal symmetry relations that have been discovered in this context. The systems considered are driven out of equilibrium by time-dependent forces or by coupling to large reservoirs of particles and energy. The symmetry relations are established for the exchange of energy and particles between the subsystem and its environment. These results have important consequences. In particular, generalizations of the Kubo formula and the Casimir-Onsager reciprocity relations can be deduced beyond linear response properties. Applications to electron quantum transport in mesoscopic semiconducting circuits are discussed.Comment: Chapter contributed to: R. Klages, W. Just, and C. Jarzynski (Eds.), Nonequilibrium Statistical Physics of Small Systems: Fluctuation Relations and Beyond (Wiley-VCH, Weinheim, 2012; ISBN 978-3-527-41094-1

Polymer sequencing by molecular machines: A framework for predicting the resolving power of a sliding contact force spectroscopy sequencing method

We evaluate an AFM-based single molecule force spectroscopy method for mapping sequences in otherwise difficult to sequence heteropolymers, including glycosylated proteins and glycans. The sliding contact force spectroscopy (SCFS) method exploits a sliding contact made between a nanopore threaded over a polymer axle and an AFM probe. We find that for sliding α- and β- cyclodextrin nanopores over a wide range of hydrophilic monomers, the free energy of sliding is proportional to the sum of two dimensionless, easily calculable parameters representing the relative partitioning of the monomer inside the nanopore or in the aqueous phase, and the friction arising from sliding the nanopore over the monomer. Using this relationship we calculate sliding energies for nucleic acids, amino acids, glycan and synthetic monomers and predict on the basis of these calculations that SCFS will detect N- and O-glycosylation of proteins and patterns of sidechains in glycans. For these applications, SCFS offers an alternative to sequence mapping by mass spectrometry or newly-emerging nanopore technologies that may be easily implemented using a standard AFM

Mechanical Processes of a Single Synthetic Molecular Machine Studied by AFM-based Force Spectroscopy

Some biomolecules are able to generate directional forces by rectifying random thermal motions. This allows these molecular machines to perform mechanical tasks such as intracellular cargo transport or muscle contraction in plants and animals. Although some artificial molecular machines have been synthesized and used collectively to perform mechanical tasks, so far there have been no direct measurements of mechanical processes at the single-molecule level. Here we report measurements of the mechanical work performed by a synthetic molecule less than 5 nm long. We show that biased Brownian motion of the submolecular components in a hydrogen-bonded [2]rotaxane -a molecular ring threaded onto a molecular axle- can be harnessed to generate significant directional forces. We used the cantilever of an atomic force microscope to apply a mechanical load to the ring during single-molecule pulling-relaxing cycles. The ring was pulled along the axle, away from the thermodynamically favoured binding site, and was then found to travel back to this site against an external load of 30 pN. Using fluctuation theorems, we were able to relate the measurements of the work done at the level of individual molecules to the free energy change measured previously by ensemble measurements. Finally, we used dynamic single-molecule force spectroscopy to probe kinetic information of the interaction between the molecular ring and the preferred binding site. The results also demonstrate that AFM-based single-molecule force spectroscopy, which has been widely used to investigate the mechanochemical behaviour of (bio)macromolecules, can be applied to a molecule that is less than 5 nm in its extended form

PH-responsive biodegradable amphiphilic networks

Copper-mediated azide - alkyne Huisgen's 1,3-dipolar cycloaddition is a "click" reaction that was successfully used to prepare pH-responsive, amphiphilic and biodegradable networks. Indeed, this reaction proved to be very efficient in the "one pot" grafting of amino alkyne onto azide containing poly(epsilon-caprolactone) and the cross-linking of these chains by alpha,omega-dialkynyl poly(ethylene oxide). The pH-controlled release of guests hosted during the cross-linking step was illustrated with an entrapped model dye

The contribution of the Clean Development Mechanism to national climate policies

The clean development mechanism (CDM), one of the flexible mechanisms of the Kyoto Protocol, has not received noticeable attention in the applied modeling literature. In this paper we develop a policy-oriented trading model explicitly including the key features likely to influence the supply and demand of CDM projects. This model allows us to evaluate the contribution of the CDM to climate policies at the national level. With an application to Belgium we show that the CDM could reduce the cost of the Kyoto Protocol by a factor 10. Policy analyses reveal that some features (e.g. the market share) have much more influence on this result than others (notably the transaction costs). Moreover, equilibrium effects can sometimes exceed direct effects so that, all in all, a larger domestic abatement could be justified by the desire to reduce what we call carbon dependence. Policy implications and perspectives for the CDM are discussed

Convention d'assistance technique pour le calcul de coefficients d'émission de CO2 - Huile de palme

info:eu-repo/semantics/publishe

The contribution of the Clean Development Mechanism in the Belgian climate policy

The purpose of this chapter is to evaluate the potential contribution of the Clean Development Mechanism to the Belgian climate policy. For this purpose we develop a partial equilibrium model of the carbon market in which the key features of the CDM inherent in its project-based nature are explicitly considered (transaction costs, accessibility rate…). We discuss the conditions under which the CDM could significantly contribute to the Belgian climate strategy and we show that this contribution should remain rather limited due to low expected carbon prices under the first Kyoto commitment period