Maximum digestibility

In addition to the type of fatty acid, the position of the fatty acid in the TG will affect its digestibility. Maximum absorption is obtained when a poorly absorbed fatty acid is esterified at the 2-position of the TG molecule (To-marelli etai, 1968 Filer eta/., 1969) and there are unsaturated fatty acids in the 1,3-position (Mattson and Streck, 1974). A poorly absorbed acid like behenic acid (22 0) can be made partly digestible by feeding it In the form of 2-behenoyl dllinolein (Mattson and Streck, 1974). 

The cake produced by the digestion is extracted with cold water and possibly with some diluted acids from the subsequent processes. During the cake dissolution it is necessary to maintain the temperature close to 65°C, the temperature of iron sulfate maximum solubiUty. To prevent the reoxidation of the Fe " ions during processing, a small amount of Ti " is prepared in the system by the Ti reduction. The titanium extract, a solution of titanium oxo-sulfate, iron sulfate, and sulfuric acid, is filtered off. Coagulation agents are usually added to the extract to faciUtate the separation of insoluble sludge. 

The RPA is a sensitive method for quantifying specific RNAs from a mixture of RNAs. This is achieved using a small-volume hybridization of an RNA probe to the RNA under study. Unhybridized probe and sample is then digested with RNAses and the protected probe fragment is visualized after denaturing gel electrophoresis. Commonly, the probe is radiolabeled for maximum sensitivity. Following is a method for RPA detection of R-luc-4 sites and F-luc mRNA. 

Comments There are several suggested controls for this assay, including use of yeast total RNA as a negative control (check for probe species specificity) and a no RNAse control to determine probe stability. In Fig. 6.3A, the positive control marker lane was produced by addition of R-luc-4 sites or F-luc mRNA only to the assay. Also, optimal times for RNAse digestion will vary from probe to probe. In addition, for maximum sensitivity a probe with high specific activity is preferable (yet still in molar excess to the mRNA). 

Fluorescence. Upon excitation at 370 nm, the emission spectrum from the digests of glucose-exposed dentin slices showed a broad peak (maximum 420 nm), which was strongly increased compared with the background peak in buffer-exposed dentin. This background peak was no contamination of buffer salts, since it was also present in demineralized water. The broad peak at 420 nm also overlapped a broad shoulder peak at 480 nm that occurred in the buffer-exposed dentin (fig. 2). The 370/440 nm fluorescence of glucose-exposed dentin slices was significantly increased compared with controls (table 2). 

With this programme, the vessels reach a maximum temperature of 270°C at zone four. The total digestion time would be 3S minutes. Applications include measurement of total recoverable metals in waste water and the measurement of trace metals in air filters. 

The output of the digester is pumped from the helix through a pneumatically actuated valve either into the neutralization vessel or to waste. A pump was designed and built for this purpose. Its action is based on an oscillating piston, it has no moving valves and the hot acid comes into contact only with Kel-F and PTFE. The maximum flow-rate is about 12 ml min. This pump has been described in more detail elsewhere [33]. 

Table 8.10 shows the concentration range of potential toxic trace elements in U.S. sewage sludges, as summarized by Chaney (1989). In this table, data on maximum concentration of toxic trace elements in dry, digested sewage sludges are compared to concentrations of the elements in median sludges and in soils. The subsurface contamination that may result from uncontrolled disposal on land surfaces... 

Both digester systems exhibit extremely low levels of detectable cellulase activities (exoglucanase, endoglucanase, and -glucosidase) when compared to industrial saccharifying processes (See Table III) in which the hydrolysis of cellulose in the feedstock is optimized with respect to enzyme loading. Therefore, the data indicate the level of improvement that may be made to attain maximum rates for cellulose hydrolysis in the anaerobic reactor system. 

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