Gel sponge

D matrices, such as gels, sponges and porous microcarriers... 

Water vapor is removed from air either by cooling and removing the liquid water produced or by absorbing the moisture with a silica gel sponge. Then carbon dioxide reacts with lime. 

Ishikawa N, Suzuki Y, Ohta M et al (2007) Peripheral nerve regeneration through the space formed by a chitosan gel sponge. J Biomed Mater Res 83A 33 0... 

Matsuura, S, Obara, T, Tsuchiya, N, Suzuki, Y, and Habuchi, T. 2006. Cavernous nerve regeneration by biodegradable alginate gel sponge sheet placement without sutures. Urology 68(6) 1366-1371. 

It is possible to prepare different forms of formulations such as aqueous dispersions, gels, sponges and micro/nanoparticles using chitosan and its derivatives. Furthermore, versatility in the physicochemical properties of chitosan allows the formulator an excellent opportunity to engineer antigen-specific adjuvant/delivery systems. 

Performance of the adsorption dependents on the type of adsorbent used. The materials are versatile. This versatility allows the sorbent to be used under different forms, from insoluble beads, to gels, sponges, capsules, films, membranes or fibers. Materials are available in a variety of stmc-tures with a variety of properties. The surface of contact between any sorbent and the liquid phase plays an important role in the phenomena of sorption. The efficiency of adsorption depends on physicochemical characteristics such as porosity, surface specific area and particle size of sorbents. A fundamentally important characteristic of good adsorbents [188, 117] is their high porosity and consequent larger surface area with more specific adsorption sites. 

Sintering has been used to produce a porous polytetrafluoroethylene (16). Cellulose sponges are the most familiar cellular polymers produced by the leaching process (123). Sodium sulfate crystals are dispersed in the viscose symp and subsequently leached out. Polyethylene (124) or poly(vinyl chloride) can also be produced in cellular form by the leaching process. The artificial leather-tike materials used for shoe uppers are rendered porous by extraction of salts (125) or by designing the polymers in such a way that they precipitate as a gel with many holes (126). 

Further members of this class of alkaloids are the araguspongines K (10) and L (11), isolated from the marine sponge Xestospongia exigua collected at Bayadha, on the Saudi Arabian Red Sea coast [16]. After evaporation of the EtOH extract, it was partitioned between hexanes and MeCN. The polar fraction was subjected to a series of chromatographic separations by column chromatography on silica gel. The structures of both alkaloids 10 and... 

Haliclonacyclamine E (13) and arenosclerins A (14), B (15), and C (16) have been isolated from the marine sponge Arenosclera brasiliensis, endemic in Brazil. Crude extracts of this sponge displayed potent cytotoxic and antibiotic activities, and were subjected to fractionation by sihca-gel flash chromatography, medium pressure chromatography on a SiOH cyanopropyl-bonded column, and reversed-phase Cis column chromatography to give compounds 13-16 [18]. The structure elucidation was based on spectroscopic analysis, including HRFABMS, COSY, HSQC, HSQC-TOCSY, and HMBC NMR... 

Haliclonacyclamine F (25), arenosclerin D (26), and arenosclerin E (27) have been recently isolated from the sponge Pachychalina alcaloidifera endemic in Brazil [26]. The alkaloids 25-27 were isolated from the cytotoxic, antibiotic, and antituberculosis MeOH crude extract of P. alcaloidifera by a series of separations on silica-gel and cyanopropyl-bonded silica-gel columns. The structures of compounds 25-27 were established by the same approach employed for the structural elucidation of haliclonacyclamine E (13) and arenosclerins A-C (14-16) [18], as well as by comparison with NMR data for this last series of alkaloids. The alkaloids 25-27 displayed moderate cytotoxic activity against SF295 (human CNS), MDA-MB435 (human breast), HCT8 (colon), and HL60 (leukemia) cancer cell lines. 

One of the most remarkable attributes of Pechini-type routines is the behaviour of precursor resins (gels) upon heating. On the first stage of thermal decomposition of samples, being dried at approx. 120°C, they decompose forming very porous and voluminous sponge-cake-like materials [6], Probably, just at this temperature, a highly porous intermediate is... 

Orthosilicic acid, Si(OH)4, could be an appropriate precursor, but it cannot be stored in monomeric form at reasonable concentrations in aqueous solutions. It enters easily into polycondensation reactions (1) that result in its polymerization. As a monomer, the orthosilicic add exists in aqueous solutions at a concentration of less than 100 ppm [18]. This is too small to fabricate sol-gel derived materials, although diatoms and sponges have the property of concentrating silica from seawater containing only a few mg per liter [60]. Sol-gel processing in the laboratory can be performed with a rather concentrated solution of orthosilicic add. This requires freshly prepared add the procedure is time consuming which restrids its widespread use. 

One of the most promising applications of enzyme-immobilized mesoporous materials is as microscopic reactors. Galameau et al. investigated the effect of mesoporous silica structures and their surface natures on the activity of immobilized lipases [199]. Too hydrophilic (pure silica) or too hydrophobic (butyl-grafted silica) supports are not appropriate for the development of high activity for lipases. An adequate hydrophobic/hydrophilic balance of the support, such as a supported-micelle, provides the best route to enhance lipase activity. They also encapsulated the lipases in sponge mesoporous silicates, a new procedure based on the addition of a mixture of lecithin and amines to a sol-gel synthesis to provide pore-size control. 

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