Observation of individual molecules trapped on a nanostructured insulator

For the first time, ordered polar molecules confined in monolayer-deep rectangular pits produced on an alkali halide surface by electron irradiation have been resolved at room temperature by non-contact atomic force microscopy. Molecules self-assemble in a specific fashion inside pits of width smaller than 15 nm. By contrast no ordered aggregates of molecules are observed on flat terraces. Conclusions regarding nucleation and ordering mechanisms are drawn. Trapping in pits as small as 2 nm opens a route to address single molecules

Coherent electron-phonon coupling and polaron-like transport in molecular wires

We present a technique to calculate the transport properties through one-dimensional models of molecular wires. The calculations include inelastic electron scattering due to electron-lattice interaction. The coupling between the electron and the lattice is crucial to determine the transport properties in one-dimensional systems subject to Peierls transition since it drives the transition itself. The electron-phonon coupling is treated as a quantum coherent process, in the sense that no random dephasing due to electron-phonon interactions is introduced in the scattering wave functions. We show that charge carrier injection, even in the tunneling regime, induces lattice distortions localized around the tunneling electron. The transport in the molecular wire is due to polaron-like propagation. We show typical examples of the lattice distortions induced by charge injection into the wire. In the tunneling regime, the electron transmission is strongly enhanced in comparison with the case of elastic scattering through the undistorted molecular wire. We also show that although lattice fluctuations modify the electron transmission through the wire, the modifications are qualitatively different from those obtained by the quantum electron-phonon inelastic scattering technique. Our results should hold in principle for other one-dimensional atomic-scale wires subject to Peierls transitions.Comment: 21 pages, 8 figures, accepted for publication in Phys. Rev. B (to appear march 2001

Measurement of the conductance of a hydrogen molecule

Recent years have shown steady progress in research towards molecular electronics [1,2], where molecules have been investigated as switches [3-5], diodes [6], and electronic mixers [7]. In much of the previous work a Scanning Tunnelling Microscope was employed to address an individual molecule. As this arrangement does not provide long-term stability, more recently metal-molecule-metal links have been made using break junction devices [8-10]. However, it has been difficult to establish unambiguously that a single molecule forms the contact [11]. Here, we show that a single H2 molecule can form a stable bridge between Pt electrodes. In contrast to results for other organic molecules, the bridge has a nearly perfect conductance of one quantum unit, carried by a single channel. The H2-bridge provides a simple test system and a fundamental step towards understanding transport properties of single-molecule devices.Comment: 6 pages, 4 figure

eIF4A2 drives repression of translation at initiation by Ccr4-Not through purine-rich motifs in the 5'UTR

Background: Regulation of the mRNA life cycle is central to gene expression control and determination of cell fate. miRNAs represent a critical mRNA regulatory mechanism, but despite decades of research, their mode of action is still not fully understood.Results: Here, we show that eIF4A2 is a major effector of the repressive miRNA pathway functioning via the Ccr4-Not complex. We demonstrate that while DDX6 interacts with Ccr4-Not, its effects in the mechanism are not as pronounced. Through its interaction with the Ccr4-Not complex, eIF4A2 represses mRNAs at translation initiation. We show evidence that native eIF4A2 has similar RNA selectivity to chemically inhibited eIF4A1. eIF4A2 exerts its repressive effect by binding purine-rich motifs which are enriched in the 5'UTR of target mRNAs directly upstream of the AUG start codon.Conclusions: Our data support a model whereby purine motifs towards the 3' end of the 5'UTR are associated with increased ribosome occupancy and possible uORF activation upon eIF4A2 binding.</p

The Benefits of Family Science Education: The Male Perspective

The majority of university family science courses are predominantly comprised of women. Because family science classes are centered on information and concepts relevant for both men and women, it is important to understand gendered experiences to promote healthy family and romantic relationships. Not only would men benefit from these classes, but increasing male enrollment in family sciences courses will help promote gender diversity in higher education. The current study used qualitative analyses to examine the perceptions of male undergraduate students concerning the benefits of taking family science courses. Male undergraduates from three midsize universities in the Midwestern and Western United States provided open-ended responses via an online survey (N = 64). Three themes emerged: the classes provided students with valuable information; they had a better understanding of themselves and others; and the classes related to their future career path. Results provide support to promote gender diversity in family science classrooms, which is crucial for the interpersonal and educational growth of both men and women. Further implications of participant responses are discussed

Law Schools as Knowledge Centers in the Digital Age

This article explores what it would mean for law schools to be “knowledge centers” in the digital age, and to have this as a central mission. It describes the activities of legal knowledge centers as: (1) focusing on solving real legal problems in society outside of the academy; (2) evaluating the problem-solving effectiveness of the legal knowledge being developed; (3) re-conceptualizing the structures used to represent legal knowledge, the processes through which legal knowledge is created, and the methods used to apply that knowledge; and (4) disseminating legal knowledge in ways that assist its implementation. The Article uses as extended examples of knowledge centers in the digital age the research laboratories in the sciences, and in particular research laboratories in linguistics and information science. It uses numerous examples to suggest how law schools might implement the concept of a knowledge center

Law Schools as Knowledge Centers in the Digital Age

This article explores what it would mean for law schools to be “knowledge centers” in the digital age, and to have this as a central mission. It describes the activities of legal knowledge centers as: (1) focusing on solving real legal problems in society outside of the academy; (2) evaluating the problem-solving effectiveness of the legal knowledge being developed; (3) re-conceptualizing the structures used to represent legal knowledge, the processes through which legal knowledge is created, and the methods used to apply that knowledge; and (4) disseminating legal knowledge in ways that assist its implementation. The Article uses as extended examples of knowledge centers in the digital age the research laboratories in the sciences, and in particular research laboratories in linguistics and information science. It uses numerous examples to suggest how law schools might implement the concept of a knowledge center