Loading and Activation

SH Gehrke, LH Uhden, JF McBride. Enhanced loading and activity retention in hydrogel delivery systems. J Controlled Release. 21-33 (1998). 

Capsules with high enzyme loading and activity prepared by templating BMS spheres can also be used as biomimetic reactors [89]. For example, PGA/ PLL capsules with pre-loaded urease (prepared via a BMS sacrificial template) are capable of catalyzing the hydrolysis of urea and have been shown to induce the exclusive formation of CaC03 particles inside the capsules [89]. 

Maier, L.S., Zhang, T., Chen, L., et al., 2003, Transgenic CaMKIIdeltaC overexpression uniquely alters cardiac myocyte Ca2+ handling reduced SR Ca2+ load and activated SR Ca2+ release. Circ Res, 92(8), pp 904-11. 

Finally, remote loading and active loading [11] are other methods used to achieve high trapping efficiency in liposome formulations, but unfortunately they can only be applied to a small number of drugs with specific physicochemical properties. This technique will be discussed below in Section 5.3.23. 

Some important features of these models are summarized in the next section. However, it should be noted that a comprehensive quantitative mathematical model for PTC, accounting for the intrinsic kinetics of ion-exchange and main organic reaction, mass conservation of species, overall mass conservation, interphase and intraphase mass transfer, catalyst loading and activity, equilibrium partitioning of catalyst, location of reaction (organic phase, aqueous or solid phase, or interface), and flow patterns for each phase, are yet to be developed. 

The results given in Table 1 are expressed in T50 namely the temperature at which 50% conversion is reached. Table 1 also presents the number of exposed noble metal on each catalyst expressed in mmol/g of catalyst. As shown by this table, very important differences of activity are evidenced. It was thus not possible to compare all the catalysts at a common reaction temperature. Moreover, the important differences of activity do not allow any reliable comparison of turn over frequencies in this simple set of experiments. Nevertheless, it is still possible to interpret the activity as a function of the amount of metal exposed. The differences of activity between catalysts cannot be attributed to the combination of loading and dispersion. Indeed, Pd/C DP is more active with 3.3 exposed Pd/g of catalyst than Pd/C El with 3.8 exposed Pd/g of catalyst. In contrast. Figure 1 shows that an obvious relationship exists between the catalyst loading and activity expressed in T50. This correlation indicates that the catalytic activity is directly proportional to the amount of Pd deposited on the support for loadings superior to 1 wt%. It also shows that the... 

Ludewig B, Barchiesi F, Pericin M, et al. (2001). In vivo antigen loading and activation of dendritic cells via a liposomal peptide vaccine mediates protective antiviral and anti-tumour immunity. Vaccine. 19 23-32. 

Enzyme immobilisation on mesoporous silica has also proved attractive for biocatalysis applications, particularly in nonaqueous solvents, since immobilisation of enzymes results in increased mechanical stability and potential for catalyst recyclingMany factors, such as relative size of nanopore/enzyme, nanopore volume, surface characteristics of support/enzyme influence enzyme loading and activity Enzymes... 

With the set-up it is possible to study the effect of solvent additives (eg foaming control, corrosion/degradation inhibitors). Therefore, the design of the pilot is such that differeut, uou-crystallising, solvent mixtures and modified types, both state-of-the-art chemical solvents and high load and activated solvents, can be tested. 

Kang M, Bae Y-S, Lee C-H. Effect of heat treatment of activated carbon supports on the loading and activity of Pt catalyst. Carbon 2005 43(7) 1512-1516. 

Fu, Y., Li, P, Bu, L. et al (2010) Chemical/biochemical preparation of new polymeric bionanocomposites with enzyme labels immobilized at high load and activity for high-performance electrochemical immunoassay. J. Phys. Chem. C, 114,1472-1480. 

Because the Group VIA and Group VIIIA metals are most conveniently prepared as oxides, a sulfiding step is necessary. That will be discussed in Section 7 (Catalyst Loading and Activation). 

Gehrke SH, Uhden LH, McBride IF (1998) Enhanced loading and activity retention of bioactive proteins in hydrogel delivery systems. J Control Release 55 21 Gekko K, Ito H (1990) Competing solvent effects of polyols and guanidine hydrochloride on protein stabihty. J Biochem 107 572... 

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