PEDOT Modified Carbon Paste Microelectrodes for Scanning Electrochemical Microscopy

Only one measuring tip was used in three different modes of operation of the Scanning Electrochemical Microscope (feed-back mode, generation-collection mode, potentiometry) to collect chemical information about copper targets. The tip was formed from 5 and 25 μm diameter conventional platinum microdisk electrode by etching a cavity, then electrochemically depositing poly(3,4-ethylenedioxythiophene) (PEDOT) layer doped with hexacyanoferrate and finally filling with modified carbon paste based Cu2+ sensing layer. The preparation and electrochemical working parameters of this kind of solidcontact microelectrodes are discussed as well as SECM applications for copper detection is reported. (doi: 10.5562/cca1784

Transanal Minimally Invasive Surgery: A Promising Alternative for Certain Advanced Rectal Cancer Patients

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Modeling Hygroelastic Properties of Genetically Modified Aspen

Numerical and three-dimensional finite element models were developed to improve understanding of major factors affecting hygroelastic wood properties. Effects of chemical composition, microfibril angle, crystallinity, structure of microfibrils, moisture content, and hydrophilicity of the cell wall were included in the model. Wood from wild-type and decreased-lignin transgenic aspen (Populus tremuloides Michx.) was used for experimental validation of the computer model. The model was able to predict longitudinal elastic modulus of microfibrils and woody cell walls. The difference in longitudinal elastic properties between wild-type and genetically modified aspen wood was predicted well only when additional softening of hemicelluloses and amorphous cellulose of transgenic aspen was included in the model

Electrochemical and spectroscopic study of C12H25X molecules adsorption on copper sheets, X (-SH, -S-S-, -SeH and -Se-Se-)

In this contribution, we explored the possibility of using selenol and selenide molecules to form self-assembled monolayers (SAMs) on copper, in order to check the influence of anchoring groups on SAMs quality and compared it to well-known thiolate assemblies (formed with thiol and disulfide molecules). Precisely, monolayers of pure alkane chains have been self-assembled on electroreduced bulk copper. The different selected molecules present the following reactive anchoring groups: thiol (R-SH), disulfide (R-S-S-R), selenol (R-SeH) and diselenide (R-Se-Se-R), where R = C12H25-. Electrochemical (cyclic voltammetry and scanning electrochemical microscopy) techniques and spectroscopic (X-ray photoelectron and polarization modulation infrared reflection absorption spectroscopy) have been used to characterize the surface composition and monolayer organization. Atomic force microscopy (AFM) measurements complete this study. All molecules analyzed have been shown to form monolayers of variable quality. The R-SH and R-SeH monolayers seem to lead to better organized and insulating layers than the R-S-S-R and R-Se-Se-R monolayers. However, the case of the diselenide is more complex and could lead to some interesting properties. (C) 2009 Elsevier Ltd. All rights reserved

Lithocholic acid, a bacterial metabolite reduces breast cancer cell proliferation and aggressiveness

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