137 research outputs found
Iso-geraniol (3,7-dimethyl-3,6-octadien-1-ol): A novel monoterpene in Vitis vinifera L. cv. Muscat Roy
Isogeraniol (3,7-Dimethyl-3,6-octadien-1-ol): Ein neues Monoterpen bei der Sorte Muscat Roy (Vitis vinifera L.)Der Monoterpengehalt im Most der Neuzüchtung Vitis vinifera L. cv. Muscat Roy und ihrer Elternsorten Muscat Frontignan und Dabuki wurde untersucht. Das Monoterpenprofil von Muscat Roy ist dem von Muscat Frontignan sehr ähnlich. Trotzdem enthält es wesentlich höhere Konzentrationen an Geraniol und α-Terpineol. Im Most von Muscat Roy wurde ein neuer Monoterpenalkohol, 3,7-Dimethyl-3,6-octadien-1-ol (Isogeraniol) identifiziert; im Most der Elternsorten ist jedoch kein Isogeraniol nachweisbar
3D Printing of Cellulose Nanocrystal-Loaded Hydrogels through Rapid Fixation by Photopolymerization
New ink compositions for direct ink writing (DIW) printing of hydrogels, combining superior rheological properties of cellulose nanocrystals (CNCs) and a water-compatible photoinitiator, are presented. Rapid fixation was achieved by photopolymerization induced immediately after the printing of each layer by 365 nm light for 5 s, which overcame the common height limitation in DIW printing of hydrogels, and enabled the fabrication of objects with a high aspect ratio. CNCs imparted a unique rheological behavior, which was expressed by orders of magnitude difference in viscosity between low and high shear rates and in rapid high shear recovery, without compromising ink printability. Compared to the literature, the presented printing compositions enable the use of low photoinitiator concentrations at a very short build time, 6.25 s/mm, and are also curable by 405 nm light, which is favorable for maintaining viability in bioinks
Studies on the interaction of the carbohydrate binding module 3 from the Clostridium thermocellum CipA scaffolding protein with cellulose and paper fibres
The adsorption of a carbohydrate binding module (CBM3) from the Clostridium thermocellum scaffolding protein (CipA) to cellulose was analysed in this work. The effect of CBM-PEG on the drainability of E. globulus and P. sylvestris pulps and on the physical properties of the respective papersheets was also studied. The CBM binding to cellulose is often described as “irreversible”, but this classification does not fully characterize this interaction. Indeed, the results obtained demonstrate that, although the adsorption on cellulose is rather stable, CBM inter-fibre mobility may be observed. The results also showed that the CBM-PEG conjugate improves the drainability of E. globulus and P. sylvestris pulps without affecting the physical properties of the papersheets.This research was supported by Fundacao para a Ciencia e a Tecnologia under grant POCTI/BIO/45356/2002
Structural and Functional Hierarchy in Photosynthetic Energy Conversion—from Molecules to Nanostructures
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
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