Laser-Cluster-Interaction in a Nanoplasma-Model with Inclusion of Lowered Ionization Energies

The interaction of intense laser fields with silver and argon clusters is investigated theoretically using a modified nanoplasma model. Single pulse and double pulse excitations are considered. The influence of the dense cluster environment on the inner ionization processes is studied including the lowering of the ionization energies. There are considerable changes in the dynamics of the laser-cluster interaction. Especially, for silver clusters, the lowering of the ionization energies leads to increased yields of highly charged ions.Comment: 10 pages, 11 figure

A Screen against Leishmania Intracellular Amastigotes: Comparison to a Promastigote Screen and Identification of a Host Cell-Specific Hit

The ability to screen compounds in a high-throughput manner is essential in the process of small molecule drug discovery. Critical to the success of screening strategies is the proper design of the assay, often implying a compromise between ease/speed and a biologically relevant setting. Leishmaniasis is a major neglected disease with limited therapeutic options. In order to streamline efforts for the design of productive drug screens against Leishmania, we compared the efficiency of two screening methods, one targeting the free living and easily cultured promastigote (insect–infective) stage, the other targeting the clinically relevant but more difficult to culture intra-macrophage amastigote (mammal-infective) stage. Screening of a 909-member library of bioactive compounds against Leishmania donovani revealed 59 hits in the promastigote primary screen and 27 in the intracellular amastigote screen, with 26 hits shared by both screens. This suggested that screening against the promastigote stage, although more suitable for automation, fails to identify all active compounds and leads to numerous false positive hits. Of particular interest was the identification of one compound specific to the infective amastigote stage of the parasite. This compound affects intracellular but not axenic parasites, suggesting a host cell-dependent mechanism of action, opening new avenues for anti-leishmanial chemotherapy

Microfabrication-based nanomechanical laboratory for testing the ductility of submicron aluminium films

International audienceThe measurement of the mechanical properties of materials with submicron dimensions is extremely challenging, from the preparation and manipulation of specimens, to the application of small loads and extraction of accurate displacements. Here, we present results obtained on 250 nm-thick aluminium films using a novel versatile concept of micro and nano-machines allowing multiple loading configurations and geometries. The focus is put on the fracture strain defined either as the strain at necking under uniaxial tension or the local strain at cracking initiation. The ductility of free-standing thin metallic films is one of the mechanical properties which is rarely measured and discussed in the literature. The necking and fracture strains are found equal to 0.08 and 0.3, respectively. Depending on the application, such as the development of flexible electronics or the reliability of interconnects, and on the loading conditions, one or both of these ductility indices can be key in the definition of fail-safe designs. This study enlightens also the interest and potential of the new nanomechanical testing concept

Occupational image, organisational image and identity in dirty work: Intersections of organisational efforts and media accounts

This article proposes that media representations of an occupational category may intersect with organizations’ efforts to construct a positive organizational identity and image. We fuse three streams of literature namely, organizational identity and image, media and the social construction of reality, and dirty work to extend extant literature on organizational identity and image. Attention is drawn to occupational image as the position of an occupational category in society. We contend that occupational image is likely to influence the decisions and actions taken by organizations and its members, in particular when the occupation is central to the organization’s mission. Occupational image is partly informed by the media. We analyse one year of media coverage of a dirty work occupation, specifically exotic dancing, and identify various ways in which the media portrays the exotic dancing occupation and the organizations providing these services. We focus upon two of these categories, namely Public (dis) Order and Art and Entertainment. We also draw upon a variety of data from one organization, For Your Eyes Only, to explore how organizational efforts to construct a positive organizational identity (based upon professionalism and legitimacy) and image (based upon fantasy, exclusivity and high quality service) intersect these media representations

Microfabrication-based nanomechanical laboratory for testing the ductility of submicron aluminium films

The measurement of the mechanical properties of materials with submicron dimensions is extremely challenging, from the preparation and manipulation of specimens, to the application of small loads and extraction of accurate displacements. Here, we present results obtained on 250 nm-thick aluminium films using a novel versatile concept of micro and nano-machines allowing multiple loading configurations and geometries. The focus is put on the fracture strain defined either as the strain at necking under uniaxial tension or the local strain at cracking initiation. The ductility of free-standing thin metallic films is one of the mechanical properties which is rarely measured and discussed in the literature. The necking and fracture strains are found equal to 0.08 and 0.3, respectively. Depending on the application, such as the development of flexible electronics or the reliability of interconnects, and on the loading conditions, one or both of these ductility indices can be key in the definition of fail-safe designs. This study enlightens also the interest and potential of the new nanomechanical testing concept. (c) 2007 Elsevier B.V. All rights reserved