Effects of Silica Hydrogel on Degumming of Fragrant Rapeseed Oil.

Hot-pressed rapeseed oils with pleasant flavor, i.e., fragrant rapeseed oils, are favored by consumers, especially people from the southwest provinces of China. Although degumming is an important section in producing edible rapeseed oils, conventional degumming techniques are generally suffered from disadvantages such as moisture control, and large losses of micronutrients and flavors. In the present paper, hot-pressed rapeseed oils were treated with silica hydrogel to remove their gums, and changes in phospholipids, acid values, peroxide values, tocopherols, total phenols, and flavor compounds were analyzed to compare the silica hydrogel-degumming with conventional methods. The optimized conditions were suggested to be carried out at 45°C for 15 min, and the silica hydrogel dosage was 1.10%. More than 97.00% of phospholipids were removed after the degumming, and more than 85.00% of micronutrients, were retained in the treated oils. The degumming efficiency was therefore significantly higher than those operated by conventional acid degumming and soft degumming techniques. It was found that the dosage of the silica hydrogel significantly affected the removal rate of phospholipids compared with degumming time and temperature. There were nearly typical volatile compounds found in the rapeseed oils, while most of them kept almost stable after the silica hydrogel-degumming. In this regard, silica hydrogel adsorption exhibited little effect on volatile compounds, making it more suitable for the production of fragrant rapeseed oils.

Synthesis and study of organo-modified silica based hydrogels: Rheological properties and drug release kinetics.

The method of synthesis of unmodified and organo-modified silica hydrogels and their composites with orotic acid as a model drug was developed. The hydrogels had a pH of 6.5-7.8. The particulate nature and highly porous structures of the hydrogel materials were revealed using scanning electron and optical microscopy methods. The content of aqueous phase in the hydrogels was 99% or more. In order to evaluate the possibility of their application as a basis for development of novel soft drug formulations and cosmetic compositions, rheological properties of the hydrogels and in vitro release kinetics of the drug were studied. The effects of synthesis conditions (increasing concentration of catalyst of silica sol formation, drug loading) and the silica matrix modification with various organic groups on the indicated properties were investigated. It was found that all synthesized hydrogels exhibited pseudoplasticity, thixotropy and controlled release of the drug, which are important for their potential application. However, in general, the indicated effects led to worsening the properties of the hydrogel materials in comparison with the unmodified silica hydrogels.

Evaluation of the Dye Extraction Using Designed Hydrogels for Further Applications towards Water Treatment.

In this work, novel chitosan-silica hydrogels were synthesized and investigated by various complementary techniques. The hydrogels were obtained via the immobilization of chitosan (Ch) on the surface of mesoporous cellular foams (MCFs). The latter silica materials were obtained by a sol-gel process, varying the composition of the reaction mixture (copolymer Pluronic 9400 or Pluronic 10500) and the ageing temperature conditions (80 °C or 100 °C). The role of the silica phase in the hydrogels was the formation of a scaffold for the biopolymeric chitosan component and providing chemical, mechanical, and thermal stability. In turn, the chitosan phase enabled the binding of anionic pollutions from aqueous solutions based on electrostatic interaction mechanisms and hydrogen bonds. To provide information on structural, morphological, and surface properties of the chitosan-silica hydrogels, analyses such as the low-temperature adsorption/desorption of nitrogen, small-angle X-ray scattering (SAXS), scanning electron microscopy (SEM), atomic force microscopy (AFM), and Fourier-transform infrared spectroscopy (FTIR) were performed. Moreover, the verification of the utility of the chitosan-silica hydrogels as adsorbents for water and wastewater treatment was carried out based on kinetic and equilibrium studies of the Acid Red 88 (AR88) adsorption. Adsorption data were analyzed by applying various equations and discussed in terms of the adsorption on heterogeneous solid-surfaces theory. The adsorption mechanism for the AR88 dye-chitosan-silica hydrogel systems was proposed.

Targeting Insect Olfaction in vivo and in vitro Using Functional Imaging.

Insects decode volatile chemical signals from its surrounding environment with the help of its olfactory system, in a fast and reliable manner for its survival. In order to accomplish this task, odorant receptors (ORs) expressed in olfactory sensory neurons (OSNs) in the fly's antenna process such odor information. In order to study such a sophisticated process, we require access to the sensory neurons to perform functional imaging. In this article, we present different preparations to monitor odor information processing in Drosophila melanogaster OSNs using functional imaging of their Ca2+ dynamics. First, we established an in vivo preparation to image specific OSN population expressing the fluorescent Ca2+ reporter GCaMP3 during OR activation with airborne odors. Next, we developed a method to extract and to embed OSNs in a silica hydrogel with OR activation by dissolved odors. The odor response dynamics under these different conditions was qualitatively similar which indicates that the reduction of complexity did not affect the concentration dependence of odor responses at OSN level.

Sustained In-Vivo Release of Triptorelin Acetate from a Biodegradable Silica Depot: Comparison to Pamorelin® LA.

Triptorelin acetate was encapsulated into silica microparticles by spray-drying a mixture of colloidal silica sol and triptorelin acetate solution. The resulting microparticles were then combined with another silica sol containing silica nanoparticles, which together formed an injectable silica-triptorelin acetate depot. The particle size and surface morphology of the silica-triptorelin acetate microparticles were characterized together with the in vitro release of triptorelin, injectability and rheology of the final injectable silica-triptorelin acetate depot. In vivo pharmacokinetics and pharmacodynamics of the silica-triptorelin acetate depot and Pamorelin® were evaluated and compared in Sprague-Dawley male rats after subcutaneous administration. Serum samples up to 91 days were collected and the plasma concentrations of triptorelin and testosterone were analyzed with ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). In vivo pharmacokinetics showed that injections of the silica-triptorelin acetate depot gave 5-fold lower Cmax values than the corresponding Pamorelin® injections. The depot also showed a comparable sustained triptorelin release and equivalent pharmacodynamic effect as the Pamorelin® injections. Detectable triptorelin plasma concentrations were seen with the depot after the 91-day study period and testosterone plasma concentrations remained below the human castration limit for the same period.

New method for the simultaneous determination of diffusion and adsorption of dyes in silica hydrogels.

The fine tuning of porosity in sol gel based devices makes possible the design of novel applications in which the transport of molecules through the oxide gel plays a crucial role. In this work we develop a new method for the simultaneous analysis of diffusion and adsorption of small diffusing probes, as anionic and cationic dyes, through silica mesoporous hydrogels synthesized by sol-gel. The novelty of the work resides in the simplicity of acquisition of the experimental data (by means of a desk scanner) and further mathematical modeling, which is in line with high throughput screening procedures, enabling rapid and simultaneous determination of relevant diffusion and adsorption parameters. Net mass transport and adsorption properties of the silica based hydrogels were contrasted to dye adsorption isotherms and textural characterization of the wet gels by SAXS, as well as that of the corresponding aerogels determined by Field Emission Scanning Electron Microscopy (FESEM) and N2 adsorption. Thus, the validation of the results with well-established characterization methods demonstrates that our approach is robust enough to give reliable physicochemical information on these systems.