Response surface suspensibility

Angellier, H., Choisnard, L., Molina-Boisseau, S., Ozil, P, Dufresne, A. (2004). Optimization of the preparation of aqueous suspensions of waxy maize starch nanocrystals using a response surface methodology. Biomacmmolecules, 5, 1545-1551. 

Figure 2 clearly indicates that a captan wettable powder containing approximately 55% captan, 33% clay, 11% dispersant, and 1% surfactant should be evaluated if maximum suspensibility is desired. In addition to indicating regions of optimal composition, response-surface maps are extremely useful in analyzing cost vs. performance. Questions such as, "What is the most economical formulation that has 60% suspensibility " may be answered objectively, without additional experimentation. 

Rabbit Ear Bioassay for Acnegenic Activity. Acnegenic activity of 2-7-DCDD, 1,2,3,4-TCDD, 2,3,7,8-TCDD, HCDD, and OCDD was tested by applying 0.1 ml of either a solvent solution or the supernatant of a solvent suspension of each compound to the inner surface of the rabbit s ears five days a week for four weeks. The ears were examined weekly for signs of chloracne, inflammation, and hyperkeratosis. The responses were divided into five categories (1) none, (2) very slight, (3) slight, (4) moderate, and (5) severe. 

Adsorption of nonionic and anionic polyacrylamides on kaolinite clay is studied together with various flocculation properties (settling rate, sediment volume, supernatant clarity and suspension viscosity) under controlled conditions of pH, ionic strength and agitation. Adsorption and flocculation data obtained simultaneously for selected systems were correlated to obtain information on the dependence of flocculation on the surface coverage. Interestingly, optimum polymer concentration and type vary depending upon the flocculation response that is monitored. This is discussed in terms of the different properties of the floes and the floe network that control different flocculation responses. Flocculation itself is examined as the cumulative result of many subprocesses that can depend differently on system properties. 

FIGURE 7.5 7,8-BPQ increases intracellular Ca2+ in murine spleen cells (A) and in both B and T cells (B). Single cell suspensions were prepared from murine spleens. Splenocytes were loaded with Fluo-3/AM dye for one hour and then treated with 7,8-BPQ, 1,6-BPQ, 3,6-BPQ, or DMSO (control). Surface-marker-defined T cells and B cells were treated with 7,8-BPQ or DMSO. Following treatment, the immediate intracellular Ca2+ response was continuously monitored for 15 minutes. Results are shown as the change in Mean Channel Fluorescence SEM. The numbers shown in this figure were the averages of triplicate determinants. Adapted from Gao et al., 2005. 

In the second type of filtration, depth or deep-bed filtration, the particles penetrate into the pores of the filter medium, where impacts between the particles and the surface of the medium are largely responsible for their removal and retention. This configuration is commonly used for the removal of fine particles from very dilute suspensions, where the recovery of the particles is not of primary importance. Typical examples here include air and water filtration. The filter bed gradually becomes clogged with particles, and its resistance to flow eventually reaches an unacceptably high level. For continued operation, it is therefore necessary to remove the accumulated solids, and it is important that this can be readily achieved. For this reason, the filter commonly consists of a bed of particulate solids, such as sand, which can be cleaned by back-flushing, often accompanied by... 

Diamond occurring in the blue ground of volcanic pipes as well as freshly pulverized diamond show hydrophobic behavior. This is used in its isolation by flotation. Diamond found in sediments is hydrophilic, however. According to Plaksin and Alekseev (154), hydrophobic diamond turns slowly hydrophilic on storing with exposure to air. Hofmann (155) reported that fine particle size diamond forms stable suspensions in dilute ammonia after treatment with calcium hypochlorite. It seems rather obvious that formation of surface oxides is responsible for the hydrophilic properties. 

No effeets were reported in rabbits when 100 mg of dichlorobenzidine (free base) was plaeed in the conjunctival sac of the eye (Gerarde and Gerarde 1974). It should be noted that the authors did not report the duration of exposure or the vehicle used. However, 0.1 mL of 3,3 -dichlorobenzidine dihydrochloride in a 20% com oil suspension produced eiythema, pus, and comeal opaeity, giving a 76% score in the Draize test within an hour when placed in the conjunctival sac of the eye of the rabbit (Gerarde and Gerarde 1974). This response is very likely associated with the release of hydrochloric acid following the salt s contact with the moist surface of the eye. 

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