Dose to clear

The resist formulation was spin-coated onto a silicone wafer on which a bottom antireflective coating had been previously applied and then soft-baked for 60 seconds at 90°C on a hot plate to obtain a film thickness of 1000 nm. The resist film was then exposed to i-line radiation of 365 nm through a narrowband interference filter using a high-pressure mercury lamp and a mask aligner. Experimental samples were then baked for 60 seconds at 90°C on a hot plate and developed. The dose to clear, E0, which is the dose just sufficient to completely remove the resist film after 60 seconds immersion development in 2.38% aqueous tetramethyl ammonium hydroxide, was then determined from the measured contrast curve. Testing results are provided in Table 1. 

Osteogenic sarcomas were reported in 3 out of 5 rats administered radium for 20 days by dropper (Evans et al. 1944). Each animal was given a different estimated total dose ranging from 10 to 70 p Ci. The lowest dose to clearly induce a malignancy was 22 pCi (approximately 73 pCi/kg or 2,703 kBq/kg). 

Figure 12.4 Contrast curves for (a) positive-tone and (b) negative-tone resists. The intercept of the curve and abscissa in positive-tone resists is called the dose to clear" and is designated as Do, while in negative resists, it marks the onset of cross-linking, and is designated as Dq. This should not be confused with the lithographic dose to print, which tends to be approximately 1.6-2.2 times higher. The absolute value of the slope of the tangent to the contrast curve at its intercept with the abscissa is defined as the resist contrast. It is usually defined in terms of an auxiliary dose value Di, which is obtained by continuing the above tangent line to the full resist film thickness (normalized to 1.0).

For the acetal systems, the acdvation energy of the catalyzed hydrolysis (Eq. 2) is sufficiendy low for the reaction to slowly occur at room temperature, so that a marked dependence of dose-to-clear on the interval between exposure and development ensues. Fortunately, a simple post exposure bake is suffident to complete the reacdon in the irra ated areas, and to obliterate the post-eiq)Osure thermal history of the resist (12). The situadon is somewhat different in high vacuum exposures, where the absence of an external water source may result in add-annihUadng side reactions. A mechanism for add traps in acetal systems has been proposed (25). 

HNO3 in the spent acid. The vertical line corresponds to the mole ratio of H20/H2S04 to form the mo no hydrate H2SO4.H2O. Note that the max HNO3 solubility for each curve occurs dose to this vertical line. It is clear that both water content and HN03 content of the spent acid should be kept low in order to minimize HN03 solubility in the NG... 

Biopsy findings show disseminated muscle fiber atrophy which is confined to type 2 fibers, in many instances with type 2B (glycolytic) fibers most affected (Figure 23). Muscle necrosis is not seen, though at ultrastructural level focal myofibrillar disruption and myofilament loss may be evident. The muscle atrophy seems to be due to decreased protein synthesis, and at high doses, to increased catabolism. The reason for the selective effect on phasic, glycolytic fibers is not clear since, although steroids interfere with carbohydrate metabolism and oxidative capacity, there seems to be no overall effect on ATP levels. Nevertheless it has been... 

Infants and children older than 1 year of age are considered to be very efficient metabolizers of drugs and may actually require larger doses than those predicted by weight adjustment of adult doses or shorter dosing intervals [33], On the basis of metabolic activity, sustained-release formulations would appear to be ideal for children 1-10 years old, if bioavailability issues prove not to be problematic. The ability to clear drugs in critically ill children may be severely compromised therefore, dosing in this subgroup of patients requires careful titration [34]. 

The anti-hypertensive dose is clearly related to the dose used to treat angina although the former is a good deal higher than the latter. Both doses however clearly correlate with the experimental cardiac 3-blocking potency. 

The reader is advised to exercise caution in the extrapolation of toxicity data from animals to humans. Species-related differences in sensitivity must be accounted for. Some studies utilized to derive MRLs or otherwise extrapolate data, is dated however, they do represent the body of knowledge regarding chloroform toxicity. In addition, many of the human studies quoted involved clinical case reports in which chloroform was utilized either as an anesthetic or as an agent of suicide. Such doses are clearly excessive and would not be encountered by the general population. These and other issues are addressed in Section 2.10. 

It took almost three years, and an estimated 100,000 hours of professional effort by physieians, nurses, teehnieians and volunteers to learn all the things we wanted to know about BZ. There were many questions to answer. What dose must one give to produee inoapaeitation For that matter, how should we define incapacitation How fast did effects develop at various doses, and how long did they take to clear Was BZ equally effeetive whether taken by mouth, by vein, by muscle, through the air or on the skin What was the lowest dose that eould cause mild but significant effects - the minimal effeetive dose ... 

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