Adsorbed protein detection by scanning electrochemical microscopy

A scanning electrochemical microscopy (SECM) protein detection methodology has been developed based on the tagging of free cysteines and other nucleophiles in proteins and peptides by benzoquinone. The tagged proteins are detected by the mediated reduction of benzoquinone with a redox species produced electrochemically at the SECM tip. After careful optimization, a sensitivity in the low ng mm 2 range was reached for bovine serum albumin. One of the major advantages of the present technique is that the selectivity of the protein tagging can be tuned by changing the pH of the reaction media. Depending on the requirements, cysteine selective or general detection can therefore be achieved with a high sensitivity. As a proof of concept, this technique was applied to the detection of protein spots and to the imaging of human fingerprints and further compared to the actual SECM state-of-art approach

Soft Stylus Probes for Scanning Electrochemical Microscopy

A soft stylus microelectrode probe has been developed to carry out scanning electrochemical microscopy (SECM) of rough, tilted, and large substrates in contact mode. It is fabricated by first ablating a microchannel in a polyethylene terephthalate thin film and filling it with a conductive carbon ink. After curing the carbon track and lamination with a polymer film, the V- shaped stylus was cut thereby forming a probe, with the cross section of the carbon track at the tip being exposed either by UVphotoablation machining or by blade cutting followed by polishing to produce a crescent moon- shaped carbon microelectrode. The probe properties have been assessed by cyclic voltammetry, approach curves, and line scans over electrochemically active and inactive substrates of different roughness. The influence of probe bending on contact mode imaging was then characterized using simple patterns. Boundary element method simulations were employed to rationalize the distance-dependent electrochemical response of the soft stylus probes

The Benefits of Mutualism: A Conceptual Framework

There are three general mechanisms by which phenotypic benefits are transferred between unrelated organisms. First, one organism may purloin benefits from another by preying on or parasitizing the other organism. Second, one organism may enjoy benefits that are incidental to or a by-product of the self-serving traits of another organism. Third, an organism may invest in another organism if that investment produces return benefits which outweigh the cost of the investment. Interactions in which both parties gain a net benefit are mutualistic. The three mechanisms by which benefits are transferred between organisms can be combined in pairs to produce six possible kinds of original or ‘basal’ mutualisms that can arise from an amutualistic state. A review of the literature suggests that most or all interspecific mutualism have origins in three of the six possible kinds of basal mutualism. Each of these three basal mutualisms have byproduct benefits flowing in at least one direction. The transfer of by-product benefits and investment are common to both intra- and interspecific mutualisms, so that some interspecific mutualisms have intraspecific analogs. A basal mutualism may evolve to the point where each party invests in the other, sometimes obscuring the nature of the original interaction along the way. Two prominent models for the evolution of mutualism do not include by-product benefits: Roughgarden's model for the evolution of the damsel-fish anemone mutualism and the ‘Tit-for-Tat’ model of reciprocity. Using the conceptual framework presented here, including in particular by-product benefits, I have shown how it is possible to construct more parsimonious alternatives to both models.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72439/1/j.1469-185X.1995.tb01196.x.pd

Whales, dolphins or fishes? The ethnotaxonomy of cetaceans in São Sebastião, Brazil

The local knowledge of human populations about the natural world has been addressed through ethnobiological studies, especially concerning resources uses and their management. Several criteria, such as morphology, ecology, behavior, utility and salience, have been used by local communities to classify plants and animals. Studies regarding fishers' knowledge on cetaceans in the world, especially in Brazil, began in the last decade. Our objective is to investigate the folk classification by fishers concerning cetaceans, and the contribution of fishers' local knowledge to the conservation of that group. In particular, we aim to record fishers' knowledge in relation to cetaceans, with emphasis on folk taxonomy. The studied area is São Sebastião, located in the southeastern coast of Brazil, where 70 fishers from 14 communities were selected according to their fishing experience and interviewed through questionnaires about classification, nomenclature and ecological aspects of local cetaceans' species. Our results indicated that most fishers classified cetaceans as belonging to the life-form 'fish'. Fishers' citations for the nomenclature of the 11 biological species (10 biological genera), resulted in 14 folk species (3 generic names). Fishers' taxonomy was influenced mostly by the phenotypic and cultural salience of the studied cetaceans. Cultural transmission, vertical and horizontal, was intimately linked to fishers' classification process. The most salient species, therefore well recognized and named, were those most often caught by gillnets, in addition to the biggest ones and those most exposed by media, through TV programs, which were watched and mentioned by fishers. Our results showed that fishers' ecological knowledge could be a valuable contribution to cetaceans' conservation, helping to determine areas and periods for their protection, indicating priority topics for research and participating in alternative management related to the gillnet fisheries

Surface engineering of wood substrates to impart barrier properties: a photochemical approach

In this study, sugar maple and white pine, two species of wood commonly used in indoor and outdoor applications, were treated by photo-initiated chemical vapor deposition to impart barrier properties. After treatment, wood wettability decreased significantly, as evidenced by water contact angle measurements (from 50° to 113° for sugar maple and 87° to 172° for white pine). Further, beyond being able to repel water, the coating shows the ability to breathe, evidenced by standardized vapor sorption tests. However, accelerated weathering via ASTM G155 testing determined that the treatment could not protect the wood from photo-degradation, or retain its properties post-weathering. This treatment could therefore be best suited for wood pre-treatment in combination with other coatings

Etude des caractères physiques réactogènes de signaux acoustiques artificiels déclencheurs de phonotropismes chez les Acrididae [Orth.]

Busnel R.-G., Loher W., Pasquinelly F. Etude des caractères physiques réactogènes de signaux acoustiques artificiels déclencheurs de phonotropismes chez les Acrididae [Orth.]. In: Bulletin de la Société entomologique de France, volume 61 (3-4), Mars-avril 1956. pp. 52-60

Etude des caractères physiques réactogènes de signaux acoustiques artificiels déclencheurs de phonotropismes chez les Acrididae [Orth.]

Busnel R.-G., Loher W., Pasquinelly F. Etude des caractères physiques réactogènes de signaux acoustiques artificiels déclencheurs de phonotropismes chez les Acrididae [Orth.]. In: Bulletin de la Société entomologique de France, volume 61 (3-4), Mars-avril 1956. pp. 52-60