Post-processing Subject

The subject of quality control and surveillance is discussed in a chapter on sterilization control and sterihty testing, whieh deals with aspects Of in-process and post-process control. 

Some foods subjected to heat or steam stress can be effectively protected by application of a FRI to their surfaces by spray or dip techniques. Application of the FRI to exposed surfaces immediately after processing can be very effective. Salt is another vehicle for post-processing application of FRIs. Oil roasted nuts, potato chips and crackers are routinely protected by FRIs, using salt as the carrier. Care must be taken to use salt with tightly-controlled specifications on its metal content. 

Post-processing and assembly methods are the operations that determine the final nature of end products. Moulded polyethylene (PE) articles may be subjected to several operations such as joining by welding (friction, vibration, hot gas and hot plate, ultrasonic, radio frequency) or gluing, machining, or decorating (Table 8.1) [1]. 

The starting point of the statistical mechanical development in [102] is the notion of a GLG. We define V (r,t) in (30) as the number of particles with velocity C at site r at time t. In contrast with the standard LB model, v, is a (positive) integer in contrast with lattice-gas models, v, > 1. The state at a particular lattice site, v(r,t), is modified by the collision process, subject to the constraints of mass and momentum conservation the post-collision state, v (r,t), is then propagated to the neighboring sites (30). 

To achieve the suitable concentration, purification and stabilization level of the nanoparticles developed by nanoprecipitation, nanoparticles are subjected to treatments after their formation. There are different techniques available to perform post-processing. The commonly used methods are shown in Fig. 9.18. These processes can be used on nanoparticles independently or consecutively. These processes are still in the research phase to determine the most efiicient combination of the sequence of processes, which provides high yield and guarantees high purity of the nanoparticles. Different processes applied for solvent elimination, purification, and stabihzation are discussed in the following sub-sections. 

Recent evidence indicates that the 5-HT transporter is subject to post-translational regulatory changes in much the same way as neurotransmitter receptors (Blakeley et al. 1998). Protein kinase A and protein kinase C (PKC), at least, are known to be involved in this process. Phosphorylation of the transporter by PKC reduces the Fmax for 5-HT uptake and leads to sequestration of the transporter into the cell, suggesting that this enzyme has a key role in its intracellular trafficking. Since this phosphorylation is reduced when substrates that are themselves transported across the membrane bind to the transporter (e.g. 5-HT and fi -amphetamine), it seems that the transport of 5-HT is itself linked with the phosphorylation process. Possibly, this process serves as a homeostatic mechanism which ensures that the supply of functional transporters matches the demand for transmitter uptake. By contrast, ligands that are not transported (e.g. cocaine and the selective serotonin reuptake inhibitors (SSRIs)) prevent the inhibition of phosphorylation by transported ligands. Thus, such inhibitors would reduce 5-HT uptake both by their direct inhibition of the transporter and by disinhibition of its phosphorylation (Ramamoorthy and Blakely 1999). 

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