Resistance inherent

Elastomeric materials, which provide relatively low practical static deflections and have relatively high natural frequencies, are used only to isolate higher frequencies. The volume compressibiUty of elastomeric materials is relatively low, therefore the shape of the elastomeric isolator must be taken into account, and space must be provided for lateral expansion. Because of their inherent resistance to chemical and environmental deterioration, neoprene and other synthetic materials often can be used in severe environments where natural materials would deteriorate. 

Polysulftde polymers provide inherent resistance to fluel and quite good resistance to alkaU. In contrast to the sihcone polymers, they have low gas... 

As previously mentioned, some urethanes can biodegrade easily by hydrolysis, while others are very resistant to hydrolysis. The purpose of this section is to provide some guidelines to aid the scientist in designing the desired hydrolytic stability of the urethane adhesive. For hydrolysis of a urethane to occur, water must diffuse into the bulk polymer, followed by hydrolysis of the weak link within the urethane adhesive. The two most common sites of attack are the urethane soft segment (polyol) and/or the urethane linkages. Urethanes made from PPG polyols, PTMEG, and poly(butadiene) polyols all have a backbone inherently resistant to hydrolysis. They are usually the first choice for adhesives that will be exposed to moisture. Polyester polyols and polycarbonates may be prone to hydrolytic attack, but this problem can be controlled to some degree by the proper choice of polyol. 

The complex polymers in feedstuffs are broken down to the constituent building blocks by a sequential process. Hydrolysis of the polymers is initiated in the lumen of the GIT by enzymes and other secretions produced by the pancreas, stomach, intestine, liver and gall bladder, and other GIT tissues, and completed by another suite of enzymes associated with the brush border membrane (BBM) or intracellular organelles. Anti-nutrient phytochemicals can decrease the hydrolysis of feedstuffs, and thereby reduce nutrient availability, either by increasing the inherent resistance of the polymers to hydrolysis or by decreasing the activities or amounts of enzymes and other secretions produced by the GIT. 

Velocity Most metals and alloys are protected from corrosion, not by nobility [a metal s inherent resistance to enter into an electrochemical reaction with that environment, e.g., the (intrinsic) inertness of gold to (almost) everything but aqua regia], but by the formation of a protective film on the surface. In the examples of film-forming protective cases, the film has similar, but more limiting, specific assignment of that exemplaiy-type resistance to the exposed environment (not nearly so broad-based as noted in the case of gold). Velocity-accelerated corrosion is the accelerated or increased rate of deterioration or attack on a metal surface because of relative movement between a corrosive fluid and the metal surface, i.e., the instability (velocity sensitivity) of that protective film. 

In view of the inherent resistance of some surfactant metabolite isomers to complete mineralisation, efforts have to be mounted in order to obtain further insight into the reasons behind the persistence of these, such as the SPC and nonylphenol ethoxy carboxylates (NPECs). In order to achieve this, it would thus be indispensable to be able to fully elucidate the chemical structure of individual components, e.g. after isolation from environmental samples. Through the application of, for example, LC-ESI-MS-MS in combination with NMR analyses, this is now possible. 

PTT fibers and yams have bulk, resiliency, stretch-recovery, softness, hand and drape, properties which are similar to those of nylons and much better than those of PET. Such materials are inherently resistant to most stains which are acidic in nature because they not have dye sites. They also have a lower static propensity than nylons. PTT fibers are dyed with disperse dyes but at a lower temperature than PET because of the polymer s lower Tt. The combinations of these properties are attractive to carpet and textile manufacturers in some applications where PTT could replace nylon or PET. PTT also offers the potential of creating new fiber products by using the unique combinations of these properties not found in either nylon or PET alone. 

Polyphenylene sulfides are inherently resistant to UV, weathering and hydrolysis. Black compounds are the most UV-resistant. 

PVC is inherently resistant to fire but rubbers are not. Consequently, the fire behaviour depends on the PVC/rubber ratio, the formulation and the use of fireproofing agents. Some TPE/PVC grades reach a UL94 VO rating. In the event of fire, beware of the fume toxicity and corrosivity. 

Efferth T, Volm M (1992) Expression of protein kinase C in human renal cell cardnoma cells with inherent resistance to doxorubicin. Anticancer Res 12 2209-2211 Eguchi Y, Srinivasan A, Tomaselli KJ, Shimizu S, Tsujimoto Y (1999) ATP-dependent steps in apoptotic signal transduction. Cancer Res 59 2174-2181 Ek TP, Campbell MD, Deth RC, Gowraganahalli J (1989) Reduction of norepinephrine-induced tonic contraction and phosphoinositide turnover in arteries of spontaneously hypertensive rats. A possible role for protein kinase C. Am J Hy-pertens 2 40-45... 

The actual number of cells or percentage of microbial population that will be killed by an absorbed radiation dose depends also on various factors such as the inherent resistance of the particular organism, the growth stage, as well as environmental factors such as tem-... 

Macrolide antibiotics target the bacterial ribosome and inhibit the bacterial protein biosynthesis. Many gram-negative bacteria are inherently resistant to mac-rolides because their outer membrane is impermeable to macrolides. Several mechanisms of acquired resistance have been reported. In some cases, resistance is conferred by methylation of ribosomes by methylase enzymes, the genes of... 

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