Quantum Correlations in NMR systems

In conventional NMR experiments, the Zeeman energy gaps of the nuclear spin ensembles are much lower than their thermal energies, and accordingly exhibit tiny polarizations. Generally such low-purity quantum states are devoid of quantum entanglement. However, there exist certain nonclassical correlations which can be observed even in such systems. In this chapter, we discuss three such quantum correlations, namely, quantum contextuality, Leggett-Garg temporal correlations, and quantum discord. In each case, we provide a brief theoretical background and then describe some results from NMR experiments.Comment: 21 pages, 7 figure

Conductive cotton prepared by polyaniline in situ polymerization using laccase

The high-redox-potential catalyst laccase, isolated from Aspergillus, was first used as a biocatalyst in the oxidative polymerization of water-soluble conductive polyaniline, and then conductive cotton was prepared by in situ polymerization under the same conditions. The polymerization of aniline was performed in a water dispersion of sodium dodecylbenzenesulfonate (SDBS) micellar solution with atmospheric oxygen serving as the oxidizing agent. This method is ecologically clean and permits a greater degree of control over the kinetics of the reaction. The conditions for polyaniline synthesis were optimized. Characterizations of the conducting polyaniline and cotton were carried out using Fourier transform infrared spectroscopy, UV–vis spectroscopy, cyclic voltammetry, the fabric induction electrostatic tester, and the far-field EMC shielding effectiveness test fixture.This work was financially supported by the National Natural Science Foundation of China (21274055, 51173071), the Program for New Century Excellent Talents in University (NCET-12-0883), the Natural Science Foundation of Jiangsu Province (BK2011157), the Fundamental Research Funds for the Central Universities (JUSRP51312B), and the Program for Changjiang Scholars and Innovative Research Team in University (IRT1135)

Ultrafast transient absorption spectroscopy: principles and application to photosynthetic systems

The photophysical and photochemical reactions, after light absorption by a photosynthetic pigment–protein complex, are among the fastest events in biology, taking place on timescales ranging from tens of femtoseconds to a few nanoseconds. The advent of ultrafast laser systems that produce pulses with femtosecond duration opened up a new area of research and enabled investigation of these photophysical and photochemical reactions in real time. Here, we provide a basic description of the ultrafast transient absorption technique, the laser and wavelength-conversion equipment, the transient absorption setup, and the collection of transient absorption data. Recent applications of ultrafast transient absorption spectroscopy on systems with increasing degree of complexity, from biomimetic light-harvesting systems to natural light-harvesting antennas, are presented. In particular, we will discuss, in this educational review, how a molecular understanding of the light-harvesting and photoprotective functions of carotenoids in photosynthesis is accomplished through the application of ultrafast transient absorption spectroscopy

Properties, production, and applications of camelid single-domain antibody fragments

Camelids produce functional antibodies devoid of light chains of which the single N-terminal domain is fully capable of antigen binding. These single-domain antibody fragments (VHHs or Nanobodies®) have several advantages for biotechnological applications. They are well expressed in microorganisms and have a high stability and solubility. Furthermore, they are well suited for construction of larger molecules and selection systems such as phage, yeast, or ribosome display. This minireview offers an overview of (1) their properties as compared to conventional antibodies, (2) their production in microorganisms, with a focus on yeasts, and (3) their therapeutic applications

Enzymatic oligomerization and polymerization of arylamines: state of the art and perspectives

The literature concerning the oxidative oligomerization and polymerization of various arylamines, e.g., aniline, substituted anilines, aminonaphthalene and its derivatives, catalyzed by oxidoreductases, such as laccases and peroxidases, in aqueous, organic, and mixed aqueous organic monophasic or biphasic media, is reviewed. An overview of template-free as well as template-assisted enzymatic syntheses of oligomers and polymers of arylamines is given. Special attention is paid to mechanistic aspects of these biocatalytic processes. Because of the nontoxicity of oxidoreductases and their high catalytic efficiency, as well as high selectivity of enzymatic oligomerizations/polymerizations under mild conditions-using mainly water as a solvent and often resulting in minimal byproduct formation-enzymatic oligomerizations and polymerizations of arylamines are environmentally friendly and significantly contribute to a "green'' chemistry of conducting and redox-active oligomers and polymers. Current and potential future applications of enzymatic polymerization processes and enzymatically synthesized oligo/polyarylamines are discussed

Non-reciprocal ultrafast laser writing

Photosensitivity is a material property that is relevant to many phenomena and applications, from photosynthesis and photography to optical data storage and ultrafast laser writing. It was commonly thought that, in a homogeneous medium, photosensitivity and the corresponding light-induced material modifications do not change on reversing the direction of light propagation. Here we demonstrate that when the direction of the femtosecond laser beam is reversed from the +z to -z direction, the structures written in LiNbO3 crystal when translating the beam along the +y and -y directions are mirrored. In a non-centrosymmetric medium, modification of the material can therefore differ for light propagating in opposite directions. This is the first evidence of a new optical phenomenon of non-reciprocal photosensitivity. We interpret this effect in terms of light pressure and associated heat flow, resulting in a temperature gradient in homogeneous media without inversion symmetry under uniform intense irradiation