Biological particulate systems

The Army Chemical Corps has developed a hypothetical system for the detection and early warning of biological particulates in air and has developed prototype electronic equipment for measuring and counting air-borne particles... 

Nanocarriers are particulate systems with size ranging from 1 nm to 1000 nm. They have been successfully utilized in the diagnosis, treatment, and monitoring of various diseases. Nanocarriers with optimized physicochemical and biological properties are taken up by cells more easily than the larger molecules, so they can be successfully used as delivery tools for currently available bioactive compounds (Emerich and Thanos, 2007). 

Biological Targeting Particulate systems especially are subject to early filtration in the limg, liver, spleen and kidney. 

Good et al. (1966) laid down some further criteria for the design of new buffers for biological research. They were concerned with pAa values between 6 and 8, because this corresponds to the pH region where most biological reactions occur and where fewest buffers are available. Solubility was required to be high in water but low in other solvents so that in particulate systems there would be very little of the buffer inside the particulate phase, and so that the buffers would... 

Similar particulate systems with a polyelectrolyte polymer core have been developed for the immobilisation of nanoparticles and enzymes (Lu et al, 2009b). In both cases the core of the particles was used for stabilising the catalytic systems, preventing their agglomeration and for easier handling and recovery after the completion of the reaction. In the case of the enzymes, polyelectrolyte polymer core particles present a better way of enzyme immobilisation than immobilisation on solid surfaces. The mild conditions inside the poly electrolyte core preserve the native conformation and biological activity of enzymes. 

Issues Encountered in the Size Characterization of Biological and Pharmaceutical Particulate Systems... 

The special needs of size characterization methods for the biological and pharmaceutical systems that are now so important in the medical sciences today are reviewed. Submicrometre and subcolloidal particulate systems are more frequently encountered that do not have the sharply defined interfaces familiar to the analyst of 25 years ago. Philosophically it is pointed out that many particles with indeterminate interfaces will move under the application of external forces as if they were inside a sphere of influence and it is, in fact, the dimensions of this sphere that are measured. Under these conditions it is valid to measure the particle size characteristics of particles down to the molecular dimensions, at least, of some of the larger protein molecules, and some methods will certain reach down into these size regions without excessive difficulty. 

Almost all cooling water system deposits are waterborne. It would be impossible to list each deposit specifically, but general categorization is possible. Deposits are precipitates, transported particulate, biological materials, and a variety of contaminants such as grease, oil, process chemicals, and silt. Associated corrosion is fundamentally related to whether deposits are innately aggressive or simply serve as an occluding medium beneath which concentration cells develop. An American... 

The dominant processes controlling the movements of P through terrestrial ecosystems are schematically presented in Fig. 14-4. In a general way, the overall movement of P on the continents may be envisioned as the constant erosion of P from continental rocks and transport in both dissolved and particulate form by rivers to the ocean, stopping occasionally along this pathway to interact with biological and mineralogical systems. 

The sediment reservoir (1) represents all phosphorus in particulate form on the Earth s crust that is (1) not in the upper 60 cm of the soil and (2) not mineable. This includes unconsolidated marine and fresh water sediments and all sedimentary, metamorphic and volcanic rocks. The reason for this choice of compartmentalization has already been discussed. In particulate form, P is not readily available for utilization by plants. The upper 60 cm of the soil system represents the portion of the particulate P that can be transported relatively quickly to other reservoirs or solubilized by biological uptake. The sediment reservoir, on the other hand, represents the particulate P that is transported primarily on geologic time scales. 

---