52 research outputs found

    Computer tomography based reconstruction of metal matrix syntactic foams

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    In order to create 3D (three-dimensional) models for finite element calculations it is necessary to reconstruct the structure of metal foam composites reinforced by hollow ceramic spheres. A new algorithm was developed for this reconstruction work. This algorithm is based on the investigation of sphericity of the shapes found on CT (computer tomograph) layer records. Using this algorithm a 3D CAD (computer aided design) model of acceptable precision can be constructed

    Structural and Functional Hierarchy in Photosynthetic Energy Conversion—from Molecules to Nanostructures

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    Basic principles of structural and functional requirements of photosynthetic energy conversion in hierarchically organized machineries are reviewed. Blueprints of photosynthesis, the energetic basis of virtually all life on Earth, can serve the basis for constructing artificial light energy-converting molecular devices. In photosynthetic organisms, the conversion of light energy into chemical energy takes places in highly organized fine-tunable systems with structural and functional hierarchy. The incident photons are absorbed by light-harvesting complexes, which funnel the excitation energy into reaction centre (RC) protein complexes containing redox-active chlorophyll molecules; the primary charge separations in the RCs are followed by vectorial transport of charges (electrons and protons) in the photosynthetic membrane. RCs possess properties that make their use in solar energy-converting and integrated optoelectronic systems feasible. Therefore, there is a large interest in many laboratories and in the industry toward their use in molecular devices. RCs have been bound to different carrier matrices, with their photophysical and photochemical activities largely retained in the nano-systems and with electronic connection to conducting surfaces. We show examples of RCs bound to carbon-based materials (functionalized and non-functionalized single- and multiwalled carbon nanotubes), transitional metal oxides (ITO) and conducting polymers and porous silicon and characterize their photochemical activities. Recently, we adapted several physical and chemical methods for binding RCs to different nanomaterials. It is generally found that the P(+)(Q(A)Q(B))(−) charge pair, which is formed after single saturating light excitation is stabilized after the attachment of the RCs to the nanostructures, which is followed by slow reorganization of the protein structure. Measuring the electric conductivity in a direct contact mode or in electrochemical cell indicates that there is an electronic interaction between the protein and the inorganic carrier matrices. This can be a basis of sensing element of bio-hybrid device for biosensor and/or optoelectronic applications

    Improving the postproduction quality of Rose cut flowers

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    In order to improve the post production quality of cut flowers of Rosa hybrida L. cv. Baroness, the effect of 8-hydroxyquinoline sulfate (8-HQS), silver thiosulfate (STS) and 1-methylcyclopropene ( I-MCP) were investigated. 8-HQS was used at 200 and 400 ppm with or without sucrose at 50 g LI. STS was used at 0.2, and 0.4 mM with or without sucrose at 50 g 1-I. l-MCP was used at 0.3, 0.5 and 0.7 g in-3 for 6h. The postproduction quality was improved as a result of using any chemical treatment comparing with untreated control. All the treatments of 8-HQS increased the vase life and minimized the percentage of weight loss of rose cut flowers compared to the control. The vase life was lorger when 8-HQS was combined with sucrose. The best treatment of 8-HQS was 400 ppm 8-HQS + 50 g 1-1 sucrose. STS treatment led to prolong the vase life and minimized the percentage of weight loss compared to the control. In addition, the effect was better when sucrose was added to STS. The treatment of STS at 0.4 mM + 50 g 1-1 sucrose was the best one. l -MCP treatment prolonged the vase life and lowered the percentage of weight loss at any level compared with untreated control. The best treatment in this concern was l -MCP at 0.5 g m-3 for 6h. The chlorophyll content (chl.a and chid)) of the leaves for the best treatment of each chemical was higher than the control. The treatment of STS at 0.4 mM + 50 g 1-1 sucrose gave the best results in this respect

    Improving the postproduction quality of Rose cut flowers

    No full text
    In order to improve the post production quality of cut flowers of Rosa hybrida L. cv. Baroness, the effect of 8-hydroxyquinoline sulfate (8-HQS), silver thiosulfate (STS) and 1-methylcyclopropene ( I-MCP) were investigated. 8-HQS was used at 200 and 400 ppm with or without sucrose at 50 g LI. STS was used at 0.2, and 0.4 mM with or without sucrose at 50 g 1-I. l-MCP was used at 0.3, 0.5 and 0.7 g in-3 for 6h. The postproduction quality was improved as a result of using any chemical treatment comparing with untreated control. All the treatments of 8-HQS increased the vase life and minimized the percentage of weight loss of rose cut flowers compared to the control. The vase life was lorger when 8-HQS was combined with sucrose. The best treatment of 8-HQS was 400 ppm 8-HQS + 50 g 1-1 sucrose. STS treatment led to prolong the vase life and minimized the percentage of weight loss compared to the control. In addition, the effect was better when sucrose was added to STS. The treatment of STS at 0.4 mM + 50 g 1-1 sucrose was the best one. l -MCP treatment prolonged the vase life and lowered the percentage of weight loss at any level compared with untreated control. The best treatment in this concern was l -MCP at 0.5 g m-3 for 6h. The chlorophyll content (chl.a and chid)) of the leaves for the best treatment of each chemical was higher than the control. The treatment of STS at 0.4 mM + 50 g 1-1 sucrose gave the best results in this respect

    La définition des interfaces pour améliorer la qualité: l'exemple de l'anorexie en hospitalisation somatique [Defining interfaces to improve quality of care: the example of anorexia nervosa in acute somatic hospitalisation]

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    Specialisation in medicine requires multidisciplinary approaches, and hence coordination in collaborations of the different partners involved. These integrated approaches, sometimes called "disease management", fit particularly well to chronic diseases. Our institution introduced an integrated approach for taking care of the acute somatic hospitalisation of patients suffering from anorexia nervosa. Interfaces with the different partners were defined, specifying tasks, rights, and duties of each person, care givers or patients. This initiative allows now to identify any deviation occurring in the process of care or hole in the care system, so that it can be corrected and recurrence prevented. This model will be extended to other complex and multidisciplinary care processes and other services in our institution

    Le sevrage ultra-rapide sous anesthésie générale: l'expérience de l'Hôpital de St-Loup [Ultrafast opiate detoxification under general anesthesia: the St. Loup Hospital experience]

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    Rapid antagonist induction under anesthesia is a method that has been increasingly used to detoxify opiate addicts. These procedures are useful to reduce the duration and the discomfort of withdrawal. However, the high risk and the cost of these methods require randomized clinical trial to evaluate safety and clinical effectiveness. The University Substance Abuse Division of Lausanne and the Intensive Care Unit of the St-Loup Hospital work on a randomized clinical trial comparing anesthesia-assisted versus traditional clonidine detoxification combined with an additional psychosocial week. This paper describes the technique of anesthesia used in our study. Our clinical experience suggests that, integrating this technique in a multidisciplinary network, with a strong emphasis on post-anesthetic follow-up, is a viable and safe option in the treatment of opiate dependence

    Anisotropic Circular Dichroism of Light-Harvesting Complex II in Oriented Lipid Bilayers: Theory Meets Experiment

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    Anisotropic circular dichroism (ACD) spectroscopy of macroscopically aligned molecules reveals additional information about their excited states that is lost in the CD of randomly oriented solutions. ACD spectra of light-harvesting complex II (LHCII)-the main peripheral antenna of photosystem II in plants-in oriented lipid bilayers were recorded from the far-UV to the visible wavelength region. ACD spectra show a drastically enhanced magnitude and level of detail compared to the isotropic CD spectra, resolving a greater number of bands and weak optical transitions. Exciton calculations show that the spectral features in the chlorophyll Q y region are well-reproduced by an existing Hamiltonian for LHCII, providing further evidence for the identity of energy sinks at chlorophylls a603 and a610 in the stromal layer and chlorophylls a604 and a613 in the lumina] layer. We propose ACD spectroscopy to be a valuable tool linking the three-dimensional structure and the photophysical properties of pigment-protein complexes
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