Water-soluble matrix fraction

Rousseau, M., Lucilia, P.M., Almeida, M.J., Milet, C., Lopez, E., 2003. The water-soluble matrix fraction from the nacre of Pinctada maxima produces earlier mineralization of MC3T3-E1 mouse pre-osteoblasts. Comp. Biochem. Physiol. B 135, 1-7. 

Recently, water-soluble protein fractions, isolated from extracts of bone matrix, were incorporated into a collagen matrix and shown to induce bone (67,68) and cartilage formation both in vitro and in vivo (69,70). In the latter studies, in the absence of the collajgen delivery system, the proteins were incapable of inducing cartilage formation in vivo when implanted intramuscularly into mice. The success of this approach appears to depend on delivering the active agents at an effective dose over an extended time period. 

Even if relatively new, HF FIFFF has been used to separate supramicrometer particles, proteins, water-soluble polymers, and synthetic organic-soluble polymers. Particle separation in HF FIFFF has recently been improved, reaching the level of efficiency normally achieved by conventional, rectangular FIFFF channels. With these channel-optimized HF FIFFF systems, separation speed and the resolution of nanosized particles have been increased. HF FIFFF has recently been examined as a means for off-line and on-line protein characterization by using the mass spectrometry (MS) through matrix-assisted laser desorption ionization time-of-flight mass spectrometry (M ALDl-TOF MS) and electrospray ionization (ESl)-TOF MS, as specific detectors. On-line HF FIFFF and ESl-TOF MS analysis has demonstrated the viability of fractionating proteins by HF FIFFF followed by direct analysis of the protein ions in MS [38]. 

The contribution of mucus carbon to Phaeocystis organic carbon can be assessed in three different ways. In the first, cells are mechanically separated from the mucus matrix by filtration through GF/C filters. Fractionation by filtration yields contributions of 5-80% of mucus carbon to POC (reviewed by Riegman and Van Boekel 1996). As many have pointed out, however, Phaeocystis cells are fragile and may be disrupted by filtration under pressure (Veldhuis and Admiraal 1985 Van Rijssel et al. 1997 Mathot et al. 2000). By releasing their water soluble carbon the fraction of mucus-carbon may be overestimated. On the other hand, mucopolysaccharides may form gels on the filter (Chin et al. 1998) as a result of which their contribution may be underestimated. Therefore, all studies in which colonies were fractionated by filtration or centrifugation have to be interpreted with care. 

Using only the standard procedure, water-soluble fractions of the original sample are obtained in the elutriate hydrophobic and even some soluble substances, which are adsorbed or immobilised to the organic or inorganic matrix by ion exchange bonds, will be retained in the solid residue. If substances with a moderate solubility... 

The NMR method was used to determine the evolution of the amorphous fraction in a trehalose powder, during a milling procedure which ultimately leads to a fully amorphous state. The purpose of the study was to determine quantitatively the amorphous fraction in crystalline-amorphous powder mixtures of trehalose, in order to assess the ability of the C NMR technique for quantitative amorphous characterisation. Poly(ethylene oxide) (PEO) was tested as a polymer matrix for solid dispersion to enhance drug bioavailability. Solid-state NMR, X-ray diffraction, and transmission electron microscopy were utilised to characterise the high miscibility between PEO and ketoprofen, a model for crystalline drugs with poor water solubility. ... 

As a first requirement, the sample analyzed should represent as closely as possible the lipid composition of the whole matrix from which it was taken furthermore, sample preparation should be carried out in such an environment as to minimize any changes in lipid properties prior to analysis. In food analysis, proper sampling of the lipid fraction requires knowledge of the physical structure and location of the major lipids in the sample, and the choice of the most adequate procedure depends on the t)q)e of food being analyzed, the nature of the lipid fraction, as well as the analytical procedure applied for the extraction. Foods consisting almost entirely of lipids, such as vegetable oils, often require little, if any, sample preparation prior to analysis. Qn the other hand, for more complex foods, such as meat or milk, extraction and purification of the lipid fraction is necessary prior to analysis. Official methods have been developed, which recommend the sample preparation and extraction procedures to be followed for a specific t)q5e of food. Solvent extraction methods are usually used, to separate lipids from water-soluble food components, prior to chromatographic analysis these are described in the sections that follow. A number of steps are usually required, prior to the solvent xtraction of lipids from a matrix ... 

Prior to phospholipid analysis, it is imperative to extract the lipids from their matrix and free them of any nonlipid contaminants. Phospholipids are generally contained within the lipid fraction, which may be recovered by the traditional Bligh and Dyer or Folch extraction procedure (9,22). In any phospholipid extraction method it is recommended to include a rather polar solvent in addition to a solvent with high solubility for lipids. The former is needed to break down lipid-protein complexes that prevent the extraction of the lipids in the organic phase. Traditionally, mixtures of chloroform and methanol (especially 2 1, v/v) have been recommended. These are washed with water or aqueous saline to remove nonlipid contaminants. Comparing the recovery of phospholipids, Shaikh found that the neutral phospholipids PC, PE, SPH as well as DPG were nearly quantitatively extracted by all solvent systems studied (Table 1), although Bligh and Dyer, in which the lower phase was removed only once, was somewhat worse (23). 

In 140 water samples from the river Saale, sampled from 1986 to 1988 according to the technique described in Section 8.1.1.1, the heavy metals iron and zinc were determined using flame AAS and lead, cadmium, chromium, cobalt, copper, and nickel by AAS with electrothermal atomization in the soluble fraction (particle diameter <0.45 pm). The sampling points, located in Thuringia (Germany), are illustrated in Fig. 8-7. The method of standard addition, with three additions, was used to minimize matrix effects. The components ammonium, chloride, magnesium, nitrate, nitrite, phosphate, oxygen,... 

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