Stability and change

SHIN T, GODBER s J, MARTIN D E, WELLS H J (1997) Hydrolytic Stability and changes in vitamers and oryzanol of extruded rice bran during storage. JFood Sci, 62(4) 704-29. 

McGue, M., Bacon, S., and Lykken, D.T. (1993) Personality stability and change in early adulthood a behavioral genetic analysis. Dev Psychol 29 96. 

Mapping techniques, and the associated bifurcation analyses, are also of great importance when applied with the Poincare map described in the appendix to chapter 5. These are used to establish local stability, and changes... 

The actions of anticonvulsants at the cellular level are complex and include facilitation of inhibitory feedback mechanisms, membrane stabilization and changes in synaptic transmission to reduce excitatory transmission. Of these various possibilities, it is widely accepted that anticonvulsants enhance GABA-mediated inhibitory processes. Such a mechanism has been clearly demonstrated for the benzodiazepines, barbiturates, diphenylhydantoin and sodium valproate. 

Current research on stability and changes of stabilizers arc published in volumes of Symposia [2J. 

Nanoparticles are discrete nanometer (10 m)-scale assemblies of atoms. Thus, they have dimensions between those characteristic of ions (lO m) and those of macroscopic materials. They are interesting because the number of atoms in the particles is small enough, and a large enough fraction of them are at, or near surfaces, to significantly modify the particle s atomic, electronic, and magnetic structures, physical and chemical properties, and reactivity relative to the bulk material. Nanoparticle surfaces themselves may be distinctive. Particles may be terminated by atomic planes or clusters that are not common, or not found, at surfaces of the bulk mineral. These, and other size-related effects will lead to modified phase stability and changes in reaction kinetics. 

It is worth noting that solid state NMR is one of the preferred techniques for the detection of changes in the polymorphs with time or temperature. Also, the occurrence of internal motions or the presence of phase transitions can be easily assessed. In several cases (e.g. sulfatiazole [34]) SSNMR was able to resolve different polymorphs that were erroneously described by other techniques, probably because of compound stability and changing hydrated form. For all these reasons solid state NMR has been widely employed for the characterization of pharma-... 

Honti, M., Istvanovics, V. and Osztoics, A. (2007) Stability and change of phytoplankton communities in a highly dynamic environment - the case of large, shallow Lake Balaton (Hungary), Hydrobiologia, 581, pp. 225-240. 

Broadhurst, P. L. and Jinks, J. L. (1966) Stability and change in the inheritance of behaviour in rats a further analysis of statistics from a diallel cross. Proc. roy Soc. B, 165,450-472. 

Temperature. Quantitative comparisons of the LLE steps require a constant temperature. Pesticide stability and changes in the relative solvent volumes are also affected by temperature. 

Fig. 4.3 The potential difference between the stable steady states changes their relative stability and changes the direction of front propagation...

Isothermal microcalorimetry is a versatile method that can be used for diverse applications such as assessing chemical stability, heats of dissolution by solution calorimetry, and binding affinities by titration calorimetry. An important application of isothermal microcalorimetry related to characterization of solids is the determination of the amorphous content [9]. Typically, it is desired that the product of a crystallization process is 100% crystalline. If the crystallization process is carried out in a nonoptimized way, the resulting solid may contain amorphous fractions. One possible cause for this could be that the crystallization is carried out too fast. Also, processes following the crystallization process, such as drying or milling, may induce formation of amorphous fractions. In most instances such amorphous fractions are undesired, since they may reduce the chemical stability and change the dissolution characteristics of the product. 

The main physico-chemical characteristics that need to be controlled in cosmetic emulsions are their formation and stability on storage as well as their rheology, which controls spreadability and skin feel. Most cosmetic and toiletry brands have a relatively short life span (3-5 years) and hence development of the product should be rapid. Consequently, accelerated storage testing is needed to predict stability and change of rheology with time. These accelerated tests represent a challenge to the formulation chemist. 

Ideally, only one set of stability measurements would be required to define the stability of a given product. These results could then be applied to all subsequent batches of the product. This could only be the case if all batches were manufactured identically. However, many of the processes that constitute the manufacturing chain cannot be completely controlled. There is, therefore, the possibility that batch to batch variation may lead to unpredictable stability and changes in the physical properties of the product. Many examples illustrate that dramatic changes in stability may be caused by minor changes in the input materials [1]. 

Lupton, A. 1996. Stability and Change Sociopolitical Development in North Mesopotamia and South-East Anatolia 4000-2700 B.C. BAR International Series 627. Oxford Tempvs Reparatvm. 

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