Structure-conductivity relationship

Watanabe, M., Nagano, S., Sanvi, K., and Ogata, N. 1987. Structure-conductivity relationship in polymer electrolytes formed by network polymers from poly[dimethylsiloxane-g-poly(ethylene oxide)] and litegum perchlorate. Journal of Power Sources 20, 327-332. 

It is helpful to use a more restrictive definition that classifies polymers as those materials which are based on covalently bonded chain structures formed by repetition of similar units, in which the chains are of sufficient length to confer on the material some additional properties not possessed by the individual units. Some of these properties are morphological and have a considerable bearing on structure-conductivity relationships in polymer electrolytes, as will be discussed later. 

Like polysulfide polymers, most of the polydiselenides and polyditellurides, being insoluble, have not been properly characterized, and their molecular weights are not available. Controversy exists on the crystalline nature of polyditellurides and formation of cyclics during the polycondensation to form polyditellurides. Due to the presence of metals, these polymers are attracting attention for their conducting properties. However detailed investigations are needed to establish structure-conductivity relationships for exploiting their potential. 

The past three decades have been devoted to establishing the majority of the polymer electrolytes and gathering understanding of their conduction mechanism, and their structure-conductivity relationships. In addition to solvating polymers, there are now clear indications that the materials should no longer be compared to solutions but to molten salts (Araujo et al, 1996b Sequeira et af, 1998). The main driving force has been the improvement of the conductivity values, especially at room temperature and below, with the perspective of battery and fuel cell applications. 

The structure/property relationships in materials subjected to shock-wave deformation is physically very difficult to conduct and complex to interpret due to the dynamic nature of the shock process and the very short time of the test. Due to these imposed constraints, most real-time shock-process measurements are limited to studying the interactions of the transmitted waves arrival at the free surface. To augment these in situ wave-profile measurements, shock-recovery techniques were developed in the late 1950s to assess experimentally the residual effects of shock-wave compression on materials. The object of soft-recovery experiments is to examine the terminal structure/property relationships of a material that has been subjected to a known uniaxial shock history, then returned to an ambient pressure... 

To illustrate the effect of radial release interactions on the structure/ property relationships in shock-loaded materials, experiments were conducted on copper shock loaded using several shock-recovery designs that yielded differences in es but all having been subjected to a 10 GPa, 1 fis pulse duration, shock process [13]. Compression specimens were sectioned from these soft recovery samples to measure the reload yield behavior, and examined in the transmission electron microscope (TEM) to study the substructure evolution. The substructure and yield strength of the bulk shock-loaded copper samples were found to depend on the amount of e, in the shock-recovered sample at a constant peak pressure and pulse duration. In Fig. 6.8 the quasi-static reload yield strength of the 10 GPa shock-loaded copper is observed to increase with increasing residual sample strain. 

In 2000, Simig et al. began to conduct structure activity relationships on 25 by employing the Pictet-Gams reaction. Compound 25 had been identified as an anxiolytic agent that does not show sedative side-effects. ... 

Transformation Rates. A literature search was conducted to determine rates of oxidation, hydrolysis, photolysis, and biodegradation. When no values were found, we made estimates based on our experience, known rates for similar compounds, and structure-activity relationships. In cases where there was great uncertainty, a transformation rate of zero was assumed so that the compound would be considered persistent. This would force a more detailed fate assessment to be conducted if considerations of toxicity indicated that the compound might be hazardous. 

Ab initio calculations, correlations of molecules geometries, spectroscopic data with chemical properties, and quanta-tive structure-activity relationship have been conducted for both furazans and furoxans. Thus, the structures of 1,2,5-oxadiazole (furazan) and benzo[c][l,2,5]oxadiazole (benzofurazan) have been calculated by ab initio and Becke3-LYP... 

A number of experiments have been conducted to establish various aspects of structure-activity relationships (SAR) of substrates. Although the greatest emphasis has been upon the nature and orientation of the side chains on the glycerol backbone, variations in the phosphate headgroup have also been explored. 

As of the end of 1980, two-thirds of PMNs submitted contained no toxicity information whatsoever. Preliminary statistics from 1981 indicate that a greater percentage of PMNs during the past year contained more toxicity testing information. Still, there were few chronic toxicity data. The lack of such information has meant that EPA s evaluations have had to be conducted on the basis of structure-activity relationships. Such analyses involve comparing the PMN chemicals to existing ones with similar structures whose toxicities are known. 

Through scientific procedures or through experience based on common use in food if used in food prior to 1958. FEXPAN uses the same criteria described above to conduct GRAS assessments namely, exposure, natural occurrence, chemical identity, structure-activity relationships, metabolism, pharmacokinetics, and toxicity data. 

Martial MA, Carlson SL, and Madara JL [1987] Partitioning of paracellular conductance along the ileal crypt-villus axis a hypothesis based on structural analysis with detailed consideration of tight junction-structure function relationships. J Membr Biol 80 59-70... 

The Xenopus oocyte can reliably express LGIC receptors. In our laboratory, we have seen robust expression of the Torpedo nAChR, 5-HT3 receptors and various GABAa receptor subtypes in oocytes. Injection of cRNA transcripts is a convenient and reproducible way to achieve the expression levels needed for functional analysis of receptor subtypes. We have found that functional characterization with this system complements biochemical experiments conducted on native receptors or those that have been expressed in mammahan cells. A combination of these approaches is essential for furthering our understanding of structure-function relationships in these receptors. 

In a study conducted by Szardenings et various combinatorial libraries of DPKs scaffolds were created to design and evaluate the activity of DPKs as inhibitors of the matrix metalloproteinases, namely, collegenase-1 and gelatinase B. This study created structure-activity relationships (SAR) for side chains attached to a DPK core structure. These enzymes are therapeutic targets with indications in the treatment of cancer, arthritis, autoimmunity, and cardiovascular disease. 

Recently, hologram quantitative structure-activity relationship (HQSAR) was conducted by Moda et al. [63] on a series of structurally diverse molecules with known PPB. The best statistical model (n — 250, r2 = 0.91, and q2 — 0.72) was used to predict the PPB of 62 test set compounds, and the predicted values were in good agreement with the experimental results (ntest —62, q2 — 0.86, RMSEtest = 12%). It is indicated that this model used a much smaller data set than the VolSurf and Wang7s models. 

In in vitro permeability studies conducted in static systems, the UWL adjacent to the membrane can be up to 1500-4000 j,m thick, whereas in vivo the UWL is only 30-300 j,m in the GI tract and is negligible for the BBB [71]. The experimental system is often stirred or shaken to minimize the effects of the UWL. An orbital shaker is often not effective and can be modified by adding beads to enhance the agitation. Recently, it has been clearly demonstrated that the quantitative structure activity relationship was interfered if the UWL limited... 

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