Papers by Keyword: Gels

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Authors: Peih Jeng Jiang, Sarika Patel, Uwe Gbureck, Liam M. Grover
Abstract: There is a current need for the localized delivery of antibiotics in order to treat implant based infections. In this study, the efficacy of hydroxyapatite (HA) gels, HA cements, and silica gels in the delivery of vancomycin have been investigated and compared. Vancomycin release was monitored at set time points using a UV/VIS spectrophotometer (288 nm). The activity of the vancomycin released from the cements and gels was assessed using an agar diffusion test with Staphylococcus aureus. Vancomycin was released rapidly from both HA matrices, and the silica gel in the first day of the experiment, but the release rate was slowed considerably after 3 days for the HA gels. Following ten days of aging, 70% of the vancomycin remained in the HA gel matrix and the quantity released from the gel was shown to retain its effectiveness against Staphylococcus aureus.
Authors: Kiyotaka Tanaka, Kenichi Kakimoto, Hitoshi Ohsato
Abstract: The development of lead-free piezoelectric materials has been required from the viewpoint of environmental preservation. We focused the lead-free KNbO3-based systems, and used a chemical solution deposition (CSD) process to obtain their precursor. (Na1-xKx)NbO3 precursor solutions were prepared from metal alkoxides and solvents such as absolute ethanol and 2-methoxyethanol. Crystallization behavior of the precursor gels obtained from the above solutions was investigated by the thermogravimetry differential thermal analysis (TG-DTA) measurement.
Authors: J. Badenes, M. Llusar, J.B. Vicent, E. Cordoncillo, J.B. Carda, G. Monrós
Authors: Teruhisa Makino, Masashi Arimura, Yoko Yamashita, Kunitaka Fujiyoshi, Makoto Kuwabara
Authors: Yasuhiro Kakinuma, Singo Takezawa, Tojiro Aoyama, Katsutoshi Tanaka, Hidenobu Anzai
Abstract: . A polishing process, which is the final process in manufacturing optical elements, takes a long time and often depends on the experience and special skills. Development of a skill-less polishing technology and automation of its process, therefore, has been required. One of the most promising polishing technologies is Field-assisted Fine Finishing (FFF). In this study, an Electro-rheological Gel (ERG) polishing pad with one-sided patterned electrodes is developed to polish insulator materials and, moreover, a novel electric-field-assisted polishing technology for glass polishing is proposed applying this pad. The ERG polishing pad can change the polishing performance according to applied electric field due to “electro-adhesion effect”. Results of several polishing tests show that the performance of polishing a blue glass can be controlled by applying electric field to the ERG pad.
Authors: Fernando dos Santos Ortega, F.A.O. Valenzuela, Victor Carlos Pandolfelli
Authors: Markus Reiner, Hubert Ceeh, Thomas Gigl, Marco Haumann, Andreas Schönweiz, Christoph Hugenschmidt
Abstract: The CDB-spectrometer at NEPOMUC enables spatially resolved Doppler Broadening Spectroscopy of the electron-positron annihilation line with a lateral resolution of up to 200~$\mu$m (FWHM). We have applied this technique for studying single particles of silica gel dependent on loading with an altering amount of the ionic liquid [C2MIM][NTf2]. Our results reveal a strong correlation between the observables of DBS and the loading factor which presumably arises from a smaller inner surface of voids in loaded silica gel.
Authors: Nicolás de la Rosa-Fox, Victor Morales-Flórez, Manuel Piñero, Luis Maria Esquivias Fedriani
Abstract: Acoustic cavitation effects in sol-gel liquid processing permits to obtain nanostructured materials, with size-dependent properties. The so-called “hot spots” produce very high temperatures and pressures which act as nanoreactors. Ultrasounds force the dissolution and the reaction stars. The products (alcohol, water and silanol) help to continue the dissolution, being catalyst content, temperature bath and alkyl group length dependent. Popular choices used in the preparation of silica-based gels are tetramethoxysilane (TMOS), Si(OCH3)4, and tetraethoxysilane (TEOS), Si(OC2H5)4. The resultant “sonogels” are denser gels with finer and homogeneous porosity than those of classic ones. They have a high surface/volume ratio and are built by small particles (1 nm radius) and a high cross-linked network with low –OH surface coverage radicals. In this way a cluster model is presented based on randomly-packed spheres in several hierarchical levels that represent the real sonoaerogel. Organic modified silicates (ORMOSIL) were obtained by supercritical drying in ethanol of the corresponding alcogel producing a hybrid organic/inorganic aerogel. The new material takes the advantages of the organic polymers as flexibility, low density, toughness and formability whereas the inorganic part contributes with surface hardness, modulus strength, transparency and high refractive index. The sonocatalytic method has proven to be adequate to prepare silica matrices for fine and uniform dispersion of CdS and PbS quantum dots (QDs), which show exciton quantum confinement. We present results of characterization of these materials, such as nitrogen physisorption, small angle X-ray/neutrons scattering, electron microscopy, uniaxial compression and nanoindentation. Finally these materials find application as biomaterials for tissue engineering and for CO2 sequestration by means the carbonation reaction.
Authors: F. Cheng, F. Lefebvre, B. Toury, S.M. Kelly, J.S. Bradley
Authors: J.L. Woodhead
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