Measurement of viability

Despite addressing different cellular functions, imaging the potassium space by or by cellular metabolic trapping of FDG, the size and severity of the defects obtained with both radionuclides by PET are virtually identical [66, 67], indicating equivalent preservation of these two measures of viability. 

The purpose of the marketing phase is introducing product concepts to potentied customers, users, and other stakeholders. In addition, the purpose of this phase includes planning for measurements of viability, acceptability, and validity. Further, initial measurements should be made to test plans, as opposed to the product, to uncover any problems before proceeding. 

In other instances, it is sufficient for the plant engineer to have a less accurate measurement of what is going on. As well as being technically suitable for the purpose, the instrument chosen will reflect these considerations. In the case of process control, the instrumentation must be reliable and it must yield information, often over very long periods of time, which represents the state of the plant or the process and its history. It is on the basis of this information that the plant engineer will make decisions, many of which will affect the economic viability of the process and some of which will have a direct impact on the safe operation of the plant. 

In a three - generation reproduction study in rats, Beliles et al. (1980) found that exposure of animals to acrylonitrile in drinking water at 70 mg/kg/day resulted in reduced viability and lactation indices in all generations. The authors considered the reduced pup indices to be the result of maternal toxicity, possibly related to reduced milk production due to decreased water intake by the dams. Fostering of pups on untreated dams lessened pup mortality. Measurement of acrylonitrile in the pups was not performed. 

Franks, F. 1982. Water activity as a measure of biological viability and quality control. Cereal Foods World 27, 403 107. 

Slade, L. and Levine, H. 1985. Intermediate moisture systems concentrated and supersaturated solutions pastes and dispersions water as plasticizer the mystique of bound water thermodynamics versus kinetics (Number 24). Presented at Faraday Division, Royal Society of Chemistry Discussion Conference - Water Activity A Credible Measure of Technological Performance and Physiological Viability Cambridge, July 1-3. 

Sperm counts can be performed with sperm from either the testis or the epididymis. Sperm motility is commonly being treated as a measure of sperm viability. The addition of sperm evaluation greatly increases the sensitivity of the study to detect effects on sperm maturation and the current study design will likely detect more male effects than previous designs even though the treatment period has been shortened. 

Because of the possible effects of active and carrier-mediated processes and metabolic biotransformation, the issue of tissue viability is important for in vitro buccal mucosal experiments. The barrier nature of the buccal mucosa resides in the upper layers of the epithelium, where unlike in the stratum corneum, the cells contain a variety of functional organelles [119, 122, 125, 150], and so tissue viability may be an important component of the barrier function of the tissue. Various methods have been employed to assess the viability of excised buccal mucosa, including measurement of biochemical markers, microscopic methods, and linearity of transport data [42], While biochemical methods, including measurement of adenosine 5 -triphosphate (ATP) levels and utilization of glucose, provide information on the metabolic activity of the tissue, this does not necessarily relate to the barrier function of the tissue. In excised rabbit buccal mucosa, levels of ATP were measured and found to decline by 40% in 6 h, and this correlated well with transmission electron microscopic evaluation of the tissue (intact superficial cells) [32], In addition, the permeability of a model peptide was unaltered up to 6 h postmortem, but at 8 h, a significant change in permeability was observed [32], These investigators therefore claimed that excised rabbit buccal mucosa could be used for diffusion studies for 6 h. 

It has been shown that radio frequency impedance (RFI) is an effective tool for moifitoring cell density and cell growth of bioprocesses. The fermentation process, quite complex, is oftentimes difficult to sample and monitor. The RFI measurement could detect cell viability of Escherichia coli during the fermentation, serving as a qualitative measure of the metabolic load of the cell, and thus provide an in situ indicator of the optimal harvesting times. 

Due to the fact that application of universal calibration is not always practical in aqueous SEC, a linear calibration method using a single polydisperse standard has a high degree of viability for characterization of water-soluble polymers. Although few water-soluble polymers with characterized MWD moments are commercially available, in many Instances an in-house polydisperse standard can be generated by measuring Mn and M, of one lot of polymer of the same chemical type as that under study. 

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