90 research outputs found

    Laser Induced Selective Alignment of Water Spin Isomers

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    We consider laser alignment of ortho and para spin isomers of water molecules by using strong and short off-resonance laser pulses. A single pulse is found to create a distinct transient alignment and antialignment of the isomeric species. We suggest selective alignment of one isomeric species (leaving the other species randomly aligned) by a pair of two laser pulses.Comment: 6 pages, 4 figures, 3 table

    Work extremum principle: Structure and function of quantum heat engines

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    We consider a class of quantum heat engines consisting of two subsystems interacting via a unitary transformation and coupled to two separate baths at different temperatures Th>TcT_h > T_c. The purpose of the engine is to extract work due to the temperature difference. Its dynamics is not restricted to the near equilibrium regime. The engine structure is determined by maximizing the extracted work under various constraints. When this maximization is carried out at finite power, the engine dynamics is described by well-defined temperatures and satisfies the local version of the second law. In addition, its efficiency is bounded from below by the Curzon-Ahlborn value 1−Tc/Th1-\sqrt{T_c/T_h} and from above by the Carnot value 1−(Tc/Th)1-(T_c/T_h). The latter is reached|at finite power|for a macroscopic engine, while the former is achieved in the equilibrium limit Th→TcT_h\to T_c. When the work is maximized at a zero power, even a small (few-level) engine extracts work right at the Carnot efficiency.Comment: 16 pages, 5 figure

    A missense mutation in Katnal1 underlies behavioural, neurological and ciliary anomalies

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    Microtubule severing enzymes implement a diverse range of tissue-specific molecular functions throughout development and into adulthood. Although microtubule severing is fundamental to many dynamic neural processes, little is known regarding the role of the family member Katanin p60 subunit A-like 1, KATNAL1, in central nervous system (CNS) function. Recent studies reporting that microdeletions incorporating the KATNAL1 locus in humans result in intellectual disability and microcephaly suggest that KATNAL1 may play a prominent role in the CNS; however, such associations lack the functional data required to highlight potential mechanisms which link the gene to disease symptoms. Here we identify and characterise a mouse line carrying a loss of function allele in Katnal1. We show that mutants express behavioural deficits including in circadian rhythms, sleep, anxiety and learning/memory. Furthermore, in the brains of Katnal1 mutant mice we reveal numerous morphological abnormalities and defects in neuronal migration and morphology. Furthermore we demonstrate defects in the motile cilia of the ventricular ependymal cells of mutants, suggesting a role for Katnal1 in the development of ciliary function. We believe the data we present here are the first to associate KATNAL1 with such phenotypes, demonstrating that the protein plays keys roles in a number of processes integral to the development of neuronal function and behaviour.Molecular Psychiatry advance online publication, 4 April 2017; doi:10.1038/mp.2017.54

    New Spin Isomers of Water Molecule

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    Abstract It is proposed the new model of interplay of water molecule with solid surface, where molecules get new physical properties the result of which one can see, for example, in the fall of vapor pressure of 1/3 compared to its original value. The water molecule loses two of three translation degrees of freedom, it loses also the full rotational spectrum but obtains mixed spin states instead of the pure original spin state which is provided by two protons inside the molecule. By taking into account the significant change in properties of molecules one can assert that the new spin isomers may exist under the certain environmental conditions. The predictions of the model are compared with experimental data within two adsorption models, one of which corresponds to the conventional case which suggests of keeping molecules on surface, and another case where molecules are found in gas. Two forms of the interpretation of experimental data give good results. The mathematical constructions of the Hopf map and of the geometric algebras are used during the creation of molecular models

    Proton exchange within water molecule

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