Resistance, causes

Dielectric Strength. Dielectric failure may be thermal or dismptive. In thermal breakdown, appHed voltage heats the sample and thus lowers its electrical resistance. The lower resistance causes still greater heating and a vicious circle, leading to dielectric failure, occurs. However, if appHed voltage is below a critical value, a stabilized condition may exist where heat iaput rate equals heat loss rate. In dismptive dielectric failure, the sample temperature does not iacrease. This type of failure is usually associated with voids and defects ia the materials. 

One approach to combating antibiotic resistance caused by P-lactamase is to inhibit the enzyme (see Enzyme inhibition). Effective combinations of enzyme inhibitors with P-lactam antibiotics such as penicillins or cephalosporins, result in a synergistic response, lowering the minimal inhibitory concentration (MIC) by a factor of four or more for each component. However, inhibition of P-lactamases alone is not sufficient. Pharmacokinetics, stability, ability to penetrate bacteria, cost, and other factors are also important in determining whether an inhibitor is suitable for therapeutic use. Almost any class of P-lactam is capable of producing P-lactamase inhibitors. Several reviews have been pubUshed on P-lactamase inhibitors, detection, and properties (8—15). 

Fewer parts required resistance cause configuration 6. More uniform physical 4. Better large-pan... 

These results made it possible to arrive at a sufficiently well-grounded conclusion that the effect of raised heat resistance caused by the formation of intermolecular chemical bonds is not very significant, and that the usually observed considerable increase of heat resistance of PAN fibres as a result of a crosslinkage with bifunctional compounds, is caused not by the formation of intermolecular chemical bonds, as it has usually been thought45, 46, but by cyclization reactions of the nitrile groups with the formation of naphthyridine cycles47. ... 

Aluminum Foil. Studies of various foods wrapped in aluminum foil show that food products to which aluminum offers only fair resistance cause little or no corrosion when the foil is in contact with a nonmetallic object (glass, plastic, ceramic, etc.) The reactions, when found, are essentially chemical, and the effect on the foil is insignificant. However, when the same foods are wrapped or covered with foil that is in contact with another metallic object (steel, tinplate, silver, etc.), an electrochemical or galvanic reaction occurs with aluminum acting as the sacrificial anode. In such cases, there is pitting corrosion of the foil, and the severity of the attack depends primarily on the food composition and the exposure time and temperature. Results obtained with various foods cov-... 

During its motion the mass experiences a resistance, caused by different factors, in particular, by air. This force of air resistance opposes the motion and it is directly proportional to the velocity ... 

Figure 6.4 shows the change in the sensor conductivity as a function of temperature. Curve / shows the dependence of sensor resistivity with temperature when the sensor is positioned in evacuated installation. The introduction of antimony hydride was made at temperature - 75°C bringing about no change in resistivity. When the temperature of the sensor was increased up to - 20 C there were no effects detected on its resistivity caused by antimony hydride. Only at higher temperatures one can observe deviation of dependence RiT) from curve 1 which is caused by decomposition of SbHa on ZnO. These results led to experiments on emission of H-atoms in a special vial when Sb-film treated by H-atoms was kept at a room temperature and sensors were kept at the temperature of - 80 C. Under these conditions, as is shown by above reasoning. 

Resistance in the arterioles of the working muscles is regulated locally. As discussed previously, active hyperemia results in production of several factors that cause metabolic vasodilation. Exercising muscles generate COz, H+ and K+ ions, heat, and adenosine. The vasodilator effect of these locally produced substances overrides the vasoconstrictor effect of the sympathetic system in the muscle. As a result, local vascular resistance is decreased. The combination of increased driving pressure and decreased local vascular resistance causes an increase in blood flow to the working muscles. 

At a certain anodic potential, the compact film breaks down and lets electrons pass through without much resistance, causing oxygen evolution at a high rate. This dielectric breakdown is discussed in more detail in Section V. 

It has been noted previously that radiation exposure of a positive resist causes chain scission in its structure. As a result, its molecular weight decreases. According to Ku and Scala (3), the decrease in the number average molecular weight resulting from such irradiation is given by the expression ... 

Around 1936, the existence of a very considerable thermal resistance at the interface between liquid helium and solids was discovered (Kapitza resistance Rk) [50], A similar effect (contact resistance Rc) is present in any contact between two materials. In the presence of a heat flux across the boundary, this thermal resistance causes a temperature discontinuity (see Fig. 4.2). 

Smith EP, Boyd J, Frank GP, Lubhan DB, Korack KS (1994) Estrogen resistance caused by a mutation in the estrogen-receptor gene in a man. N Engl J Med 331 1056... 

The electrozone sensing technique, also called the Coulter principle, was originally developed for biomedical applications for counting blood cells. This method counts and sizes particle based on changes in the electrical resistance caused by nonconductive particles suspended in an electrolyte. It presently finds uses in a wide variety of industries, including the food, environmental, coatings, ceramics, and metals industries. 

Initial resistance caused due to air-gap is very high to allow conduction of current. Hence, the arc is first initiated by narrowing its gap momentarily while 110-220 V DC is applied. Once the current picks up flow, the temperature across the arc-gap shoots up promptly. The electrodes are pulled apart leaving a gap of 20 mm to 1 cm, thereby establishing the electric arc whose temperature varies from 4000 to 8000° K. 

To avoid condensation on the smface of the windows, the overall temperature is controlled with the use of heaters located in different places within the cell. A digital camera is then placed on top of the transparent end plate and is connected to a computer that gathers and analyzes the images. The performance of these cells compared to that of typical fuel cells is usually lower due to increased ohmic resistance caused by the use of FF plates with machined-through channels. 

Karl M, Lamberts SW, Detera-Wadleigh SD, et al. (1993) Familial glucocorticoid resistance caused by a sphce site deletion in the human glucocorticoid receptor gene. J Clin Endocrinol Metab. 76, 683-689. 

As we have seen in the previous sections, our understanding of SOFC cathode mechanisms often hinges on interpretation on the magnitude and time scale of electrochemical characteristics. However, these characteristics are often strongly influenced by factors that have nothing to do with the electrode reaction itself but rather the setup of the experiment. In this section we point out two commonly observed effects that can potentially lead to experimental artifacts in electrochemical measurements (1) polarization resistance caused gas-phase diffusion and (2) artifacts related to the cell geometry. As we will... 

Oral antidiabetic agents might be indicated in noninsulin dependent diabetes mellitus (NIDDM), i.e. diabetes Type II where insulin resistance caused by down-regulation of insulin receptors or a failure of the pancreas to release insulin even though it is formed, play a role. However, oral antidiabetic... 

All -lactam antibiotics are bactericidal. They interfere with the synthesis of the bacterial wall by inhibiting the bacterial ftanspeptidase enzymes essential for the construction of peptidoglycan of the wall. Some -lactams may be inactivated by the -lactamases (penicillinases) produced by bacteria and, thus, the activity of both penicillins and cephalosporins can be determined by their ability to withstand the destructive action of -lactamases also produced by the organism for its optimal protection. Bacterial resistance caused by -lactamase production... 

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