Susceptibility to degradation

Geotextiles may be woven, nonwoven, or knitted. AH types, woven, nonwoven, or knitted, are susceptible to degradation owing to the effects of ultraviolet light and water. Thus stabilizing agents are added to the base polymeric material to lessen the effects of exposure to ultraviolet light and water. 

Like almost all synthetic polymers, styrene plastics ate susceptible to degradation by heat, oxidation, uv radiation, high energy radiation, and shear, although... 

Diethanolamine (DEA) has replaced MEA as the most widely used amine solvent. High load DEA technologies, such as that developed by Elf Aquitaine, permit the use of high (up to 40 wt % DEA) concentration solutions. The Elf Aquitaine—DEA process allows lower cinculation rates, and has consequent reductions ia capital and utility expenses. DEA tends to be more resistant to degradation by carbonyl sulfide and carbon disulfide than MEA. DEA is, however, susceptible to degradation by carbon dioxide. 

Open-loop systems have inherently long residence times which may be detrimental if the retentate is susceptible to degradation by shear or microbiological contamination. A feed-bleed or closed-loop configuration is a one-stage continuous membrane system. At steady state, the upstream... 

Penem B-Lactamase Inhibitors. The synthesis and antibacterial properties of penems, the trivial name for the 4-thia-l-azabicyclo[3.2.0]hept-2-ene ring system (24), have been reviewed (107,108). Like the closely related carbapenems, many of the penems are potent antibacterials. Additionally, penems are also susceptible to degradation by renal dipeptidase, but to a lesser extent. The limited -lactamase inhibitory data available for penems are presented in Table 4. SCH-29,482 [77646-83-4] (24, R = H, R = CH(OH)CH2, R = SCH2H ), C2qH23NO S2, is reported to be an inhibitor of type I Cephases and the OXA-2 enzyme (109). Compounds [101803-54-7] and [101914-68-5] (24, R = H, R = CH2CH(OH),... 

The acid-instabihty of erythromycin makes it susceptible to degradation in the stomach to intramolecular cyclization products lacking antimicrobial activity. Relatively water-insoluble, acid-stable salts, esters, and/or formulations have therefore been employed to protect erythromycin during passage through the stomach, to increase oral bioavakabihty, and to decrease the variabiUty of oral absorption. These various derivatives and formulations also mask the very bitter taste of macroHdes. 

Animals which are fed extensively can encounter a vast array of compounds of varying medicinal and toxic potency and susceptibilities to degradation or detoxihcation a number of texts can be consiilted. ... 

Silicone networks that form the matrix of the adhesives are not susceptible to degrade or to depolymerize when exposed to a wide range of conditions of temperature and relative humidity. Therefore, the cohesive strength will not change, as... 

Strength, particularly where the material will be subjected to fatigue loading or is susceptible to degrading mechanisms such as hydrogen-induced cracking ... 

Soil burial is widely used as the method of testing susceptibility to degradation. It closely mimics the conditions of waste disposal used for plastics but it is often difficult to reproduce results obtained because of absence of control over either the climate at the test site or the variety of micro-organisms involved in the degradation. Soil burial is thus used to provide qualitative indications of biodegradability, with more controlled laboratory work with cultured micro-organisms being used to obtain more quantitative detail. 

Most of the chemistries described above demonstrate principally a bactericidal activity. Most metalworking fluids are susceptible to degradation by filamentous fungi. The majority of commercially available water extendible metalworking fluids will contain both a bactericide and a fungicide. There are two main fungicides used in metalworking fluids. 

This system is advantageous for drugs that are highly susceptible to degradation by enzymatic processes, since it offers a protective mechanism by temporarily altering the substrate. This approach to... 

Degradation. There is, however, a second, more important, feature. Above the transition temperature we have shown that both xanthan and succinoglycan are more susceptible to degradation (5). This may be because the polymer side chains become dissociated from the main chain, in a similar manner to the unfolding of proteins. Viscosity changes, however, indicate that main chain linkages have become more... 

Effect of Binding to Proteins on Carotenoid Susceptibility to Degradation.332... 

EFFECT OF BINDING TO PROTEINS ON CAROTENOID SUSCEPTIBILITY TO DEGRADATION... 

The neck is more or less fully developed and a fibrillar structure is obtained. This structure is less susceptible to degradation because of its high degree of orientation and high crystallinity. This explains the drop and then levelling off of the carbonyl content in this latter stage. 

The relationships between the molecular structure of environmental pollutants, such as polychlorinated biphenyls (PCBs), and their rate of biodegradation are still not well understood, though some empirical relationships have been established. Self-organizing maps (SOMs) have been used to rationalize the resistance of PCBs to biodegradation and to predict the susceptibility to degradation of those compounds for which experimental data are lacking.3 The same technique has been used to analyze the behavior of lipid bilayers, following a... 

The complete degradation of isoquinoline has not been reported, which indicates that this molecule is not as susceptible to degradation as quinoline. Aislabie et al. [336] found that using an Acinetobacter strain, the degradation of isoquinoline was accompanied by the accumulation of 1-hydroxyisoquinoline. This strain did not metabolize 1,5-dihydroxyisoquinoline nor 1-methylisoquinoline. So, its inability for full degradation was explained in terms of steric hindrance. The enrichment technique leads to a metabolic improvement but results in complete degradation. 

Amylose is thus extremely susceptible to degradation in the presence of hydroxyl ion. Two mechanisms may be involved (1) a stepwise degradation caused by the reducing end-group s undergoing enolization followed by degradation to acidic products (this must occur in the presence or absence of oxygen), and (2) a random, catalytic, hydrolytic scission of 4—>l-a-D... 

The major differences between behavior profiles of organic chemicals in the environment are attributable to their physical-chemical properties. The key properties are recognized as solubility in water, vapor pressure, the three partition coefficients between air, water and octanol, dissociation constant in water (when relevant) and susceptibility to degradation or transformation reactions. Other essential molecular descriptors are molar mass and molar volume, with properties such as critical temperature and pressure and molecular area being occasionally useful for specific purposes. A useful source of information and estimation methods on these properties is the handbook by Boethling and Mackay (2000). 

Such simulations suggest that because of their relatively high water solubility which in combination with low vapor pressure causes low air-water partition coefficients, the phenols tend to remain in water or in soil and show little tendency to evaporate. Their environmental fate tends to be dominated by reaction in soil and water, and for the more sorptive species, in sediments. Their half-lives are relatively short, because of their susceptibility to degradation. 

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