Search results for " gel"
showing 10 items of 1051 documents
Salt drying: a low-cost, simple and efficient method for storing plants in the field and preserving biological repositories for DNA diversity researc…
2013
Although a variety of methods have been optimized for the collection and storage of plant specimens, most of these are not suited for field expeditions for a variety of logistic reasons. Drying specimens with silica gel in polyethylene bags is currently the standard for field-sampling methods that are suitable for subsequent DNA extraction. However, silica-gel repositories are not readily available in remote areas, and its use is not very cost-effective for the long-term storage of collections or in developing countries with limited research budgets. Salting is an ancient and traditional drying process that preserves food samples by dehydrating tissues and inhibiting water-dependent cellula…
Impact of structural features of odorant molecules on their retention/release behaviours in dairy and pectin gels
2014
International audience; Reducing of fat content in food requires a reformulation that may cause a different perception of aroma. Maintaining an adequate level of acceptability of these reformulated products for consumers requires a better understanding of the mechanisms that control the retention of odorant molecules in food matrices. Although pectins are commonly employed as thickeners, their effect on the retention of odorant molecules in nonhomogeneous products has been examined more frequently than their effect on the retention of odorant molecules in simple gels models.The purpose of this study was to explore and compare the respective effects of pectin in simple model systems. The rel…
Decorin transfection induces proteomic and phenotypic modulation in breast cancer cells 8701-BC
2008
Decorin is a prototype member of the small leucine-rich proteoglycan family widely distributed in the extracellular matrices of many connective tissues, where it has been shown to play multiple important roles in the matrix assembly process, as well as in some cellular activities. A major interest for decorin function concerns its role in tumorigenesis, as growth-inhibitor of different neoplastic cells, and potential antimetastatic agent. The aim of our research was to investigate wide-ranged effects of transgenic decorin on breast cancer cells. To this purpose we utilized the well-characterized 8701-BC cell line, isolated from a ductal infiltrating carcinoma of the breast, and two derived …
Supramolecular Eutecto Gels: Fully Natural Soft Materials
2018
The obtainment of materials featured by high environmental compatibility is one of the main goals of modern research. On this subject, we herein report the first example of supramolecular gel in deep eutectic solvents. In particular, we prepared gels of the L-amino acids isoleucine and tryptophan in choline chloride/phenylacetic acid 1:2. All gel components are readily available and nontoxic. Gels have been fully characterized by standard gelation tests, rheology, X-ray diffraction, morphology and gelation kinetics. Data collected show that gels properties depend on the gelator nature. In particular, gel phases exhibit strong colloidal forces and, this high mechanical resistance, together w…
Separation of deoxyribonucleases (DNases) of normal human stratum corneum and psoriatic scales by micro-disc-electrophoresis.
1975
Normal stratum corneum and psoriatic scales were homogenized and a differential centrifugation was performed. The DNase activity of the individual fractions was investigated by micro-disc-electrophoresis. At pH 5 only in the 600 × g pellet and 105.000 × g supernatant of normal keratin DNase activity could be observed. However, all psoriatic fractions showed distinct enzyme activities. At pH 7.4 little psoriatic DNase activity could only be demonstrated in the 105.000 × g supernatant. Except from the 15.000 × g pellet all fractions of normal stratum corneum displayed marked activities. In addition the 105.000 × g supernatant showed two different DNase bands.
Simplified models for the performance evaluation of desiccant wheel dehumidification
2002
In the present communication, simple models have been presented to evaluate the performance of rotary desiccant wheels based on different kind of solid desiccants e.g. silica gel and LiCl. The first part of the paper presents ‘Model 54’ which is developed for silica gel desiccant rotor. The model has been derived from the interpolation of experimental data obtained from the industry and the correlations have been developed for predicting outlet temperature and absolute humidity. The ‘Model 54’ consists of 54 coefficients corresponding to each correlation for outlet absolute humidity and temperature and it is found that the model predicts very well the performance of silica gel desiccant rot…
Experimental results on adsorption beds for air dehumidification
2016
Desiccant rotors are commonly used in large scale solar cooling open cycle applications. As is well known, adsorption heat sensibly reduces the dehumidification capacity of the desiccant material and results in lower system performance. The aim of this work is to describe an innovative solution that permits simultaneous mass and heat transfer. In particular, two components working with silica gel fixed beds were studied and compared. The first component is a simple packed bed containing silica gel grains. The second component is a fin and tube heat exchanger commonly used in several air conditioning applications wherein the spaces between the fins are filled with silica gel grains. In this …
A solid-phase extraction and size-exclusion liquid chromatographic method for polyethylene glycol 25 p-aminobenzoic acid determination in urine: Vali…
2007
No previous publications about percutaneous absorption of polyethylene glycol 25 p-aminobenzoic acid (PEG-25 PABA) have been found in the literature and the expected levels to be found in human urine after sunscreens use are unknown. The method proposed here is suitable to determine PEG-25 PABA in the urine of sunscreens users in order to carry out studies on body accumulation/excretion. It is based on solid-phase extraction (SPE) with size-exclusion liquid chromatography determination. Solid-phase extraction allows the analyte to be retained and subsequently eluted for a clean-up, using a silica-based cartridge. The size-exclusion liquid chromatography of the eluted allows the rest of matr…
A rapid and reliable size-exclusion chromatographic method for determination of kojic dipalmitate in skin-whitening cosmetic products
2007
A size-exclusion chromatographic method has been developed to determine the relatively novel skin-whitening agent called kojic dipalmitate (KDP) in skin-whitening cosmetic products. Preliminary experiments were carried out in order to select the solvent for standard and sample solution, and also for mobile phase composition. A PLGel Mixed-D (polystyrene/divinylbenzene co-polymer) column and isocratic mobile phase of pure tetrahydrofuran (at 1.5 mL min(-1) flow rate) were used. Detection was carried out by means of an UV/vis spectrometry detector set at 248 nm. A study of interferences reveals that KDP can be determined without interferences coming from cosmetic matrices. Most other cosmetic…
Analysis of Polycyclic Aromatic Hydrocarbons and Their Oxygen-Containing Derivatives and Metabolites in Soils
2010
Although polycyclic aromatic hydrocarbons (PAHs) have been extensively studied, the knowledge of their oxygen-containing derivatives and metabolites (OPAHs) in soils is limited. We modified and tested an existing analytical protocol involving pressurized liquid extraction of soil followed by fractionation of target compounds into PAHs and OPAHs on a silica gel column and gas chromatography/ mass spectrometry-based separation and quantification. Polycyclic aromatic hydrocarbons and carbonyl-OPAHs were quantified directly after separation on silica gel columns, and hydroxyl/carboxyl-OPAHs were quantified after silylation with N,O-bis(trimethylsilyl)trifluoroacetamide. Recoveries between 78 an…