ABSTRACT
Films of a few layers in thickness of reduced graphite oxide (RGO) sheets functionalized by the zwitterionic surfactant N-dodecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (DDPS) are obtained by using the Langmuir-Blodgett method. The quality of the RGO sheets is checked by analyzing the degrees of reduction and defect repair by means of X-ray photoelectron spectroscopy, atomic force microscopy (AFM), field-emission scanning electron microscopy (SEM), micro-Raman spectroscopy, and electrical conductivity measurements. A modified Hummers method is used to obtain highly oxidized graphite oxide (GO) together with a centrifugation-based method to improve the quality of GO. The GO samples are reduced by hydrazine or vitamin C. Functionalization of RGO with the zwitterionic surfactant improves the degrees of reduction and defect repair of the two reducing agents and significantly increases the electrical conductivity of paperlike films compared with those prepared from unfunctionalized RGO.
Subject(s)
Graphite/chemistry , Oxides/chemistry , Quaternary Ammonium Compounds/chemistry , Surface-Active Agents/chemistry , Electric Conductivity , Microscopy, Atomic Force , Oxidation-Reduction , Photoelectron Spectroscopy , Spectrum Analysis, RamanABSTRACT
The performance of femtosecond (fs) laser intrastromal ablation was evaluated with backscattering-mode adaptive-optics multiphoton microscopy in ex vivo chicken corneas. The pulse energy of the fs source used for ablation was set to generate two different ablation patterns within the corneal stroma at a certain depth. Intrastromal patterns were imaged with a custom adaptive-optics multiphoton microscope to determine the accuracy of the procedure and verify the outcomes. This study demonstrates the potential of using fs pulses as surgical and monitoring techniques to systematically investigate intratissue ablation. Further refinement of the experimental system by combining both functions into a single fs laser system would be the basis to establish new techniques capable of monitoring corneal surgery without labeling in real-time. Since the backscattering configuration has also been optimized, future in vivo implementations would also be of interest in clinical environments involving corneal ablation procedures.
ABSTRACT
We propose the use of kinoform diffractive lenses to focus near infrared femtosecond pulses in sapphire crystals for supercontinuum generation. It is shown that a strongly peaked structure appears in the blue region of the supercontinuum spectra. The central wavelength of this peak can be easily controlled by simply changing the lens-crystal distance. Moreover, when compared with the supercontinuum generated with a refractive lens in analogous conditions, the spectral extension of the so-generated continuum is larger. Our results were corroborated for sapphire plates with different thicknesses as well as in other transparent dielectrics such as fused silica.
ABSTRACT
MOTIVATION: Exploration and analysis of interactome networks at systems level requires unification of the biomolecular elements and annotations that come from many different high-throughput or small-scale proteomic experiments. Only such integration can provide a non-redundant and consistent identification of proteins and interactions. APID2NET is a new tool that works with Cytoscape to allow surfing unified interactome data by querying APID server (http://bioinfow.dep.usal.es/apid/) to provide interactive analysis of protein-protein interaction (PPI) networks. The program is designed to visualize, explore and analyze the proteins and interactions retrieved, including the annotations and attributes associated to them, such as: GO terms, InterPro domains, experimental methods that validate each interaction, PubMed IDs, UniProt IDs, etc. The tool provides interactive graphical representation of the networks with all Cytoscape capabilities, plus new automatic tools to find concurrent functional and structural attributes along all protein pairs in a network. AVAILABILITY: http://bioinfow.dep.usal.es/apid/apid2net.html. SUPPLEMENTARY INFORMATION: Installation Guide and User's Guide are supplied at the Web site indicated above.
