Critical determinant

In all of the ethylene polymerization processes, the catalyst is sensitive to feed impurities and is poisoned by most polar compounds. Many of the properties of the polymer are determined by polymerization conditions, but catalyst composition and condition are critical determinants as well. 

Fraser, N. J., Wise, A., Brown, J., McLatchie, L. M., Main, M. J., and Foord, S. M. (1999). The amino terminus of receptor activity modifying proteins is a critical determinant of glycosylation state and ligand binding of calcitonin-like receptor. Mol. Pharmacol. 55 1054-1059. 

The supply of oxygen and nutrients is a critical determinant for mammalian cell survival. Therefore, cells are located within a distance of 100 pm to maximally 150 pm of blood vessels. Multicellular... 

Diuretics promote the urinary excretion of sodium and water by inhibiting the absorption of filtered fluid across the renal tubular epithelium. The ensuing reduction in Na reabsorption reduces the Na content of the body, the critical determinant of extracellular and plasma fluid volumes. Thus, the use of diuretics is primarily indicated in the treatment of edematous diseases and of arterial hypertension. 

Interestingly, the genomic sequences of all AMPA receptor subunits contain a Q codon for this position and the R codon is selectively introduced into the GluR-B pre-mRNA by RNA editing [3]. Additionally, the Q/R site is a critical determinant of current... 

The mucosa of the GIT represents an interface between the external and internal environments. The expansive surface area is necessary for the efficient hydrolysis of foodstuffs and the absorption of energy and nutrients. The mucosa also influences the systemic availability of non-nutrient compounds in the diet, both beneficial and detrimental. Digestion and absorption of glucosinolates are critical determinants of health benefits (see Chapter 4) Similarly, the bioavailability and health benefits of phytoestrogens, such as genistein (see Chapters 5 and 10) are at least partly dependent on the carrier-mediated processes of absorption associated with the GIT (Oitate et al, 2001). Moreover, the metabolic activities of the mucosa can influence the systemic concentrations and forms of dietary phytochemicals, as exemplified by research with soy isoflavones (Andlauer et al., 2000). 

The quantity and organization of the mucosa are critical determinants of GIT functions. Feeding chicks and rats diets with tannins causes mucosal atrophy and villus shortening, with liver damage, and decreases growth and survival... 

During the screening process, building occupancy criteria help identify those buildings with sufficient occupancy to be of concern. This is a critical determination. Buildings that do not exceed the occupancy criteria can be... 

The blue book compilations [154-158] are probably the most comprehensive sources of ionization constants collected from the literature (up to the end of 1970s). These are recommended for experts in the field. On the other hand, the red books contain critically selected values [159]. The six-volume set has been put into electronic form in cooperation with NIST (National Institute of Standards and Technology), and is available at a very reasonable price [160]. A two-volume set of critically determined constants is available from Sirius Analytical Instalments Ltd., and covers molecules of particular interest to the pharmaceutical community [161,162]. In Section 3.8 at the end of this chapter, a list of gold standard pKa values of mostly drug-like molecules is presented (see Table 3.1), with many of the values determined by the author since the early 1970s. 

The deposition of ultrafine particles has been measured in replicate hollow casts of the human tracheobronchial tree. The deposition pattern and efficiency are critical determinants of the radiation dose from the short lived decay products of Rn-222. The experimental deposition efficiency for the six airway generations just beyond the trachea was about twice the value calculated if uniform deposition from laminar flow is assumed. The measured deposition was greater at bifurcations than along the airway lengths for 0.2 and 0.15 ym diameter particles ... 

K. R. Myers, A. T. Truchot, J. Ward, Y. Hudson, and J. T. Ulrich, in A. Nowotny, J. J. Spitzer, and E. Ziegler (Eds.), Endotoxin Research Series, Vol. 1, Cellular and Molecular Aspects of Endotoxin Reactions A Critical Determinant of Lipid A Endotoxic Activity, p. 145. Excerpta Medica, Amsterdam/New York/ Oxford, 1990. 

Hwa, J., Graham, R.M. and Perez, D.M. (1995) Identification of critical determinants of alpha 1-adrenergic receptor subtype selective agonist binding. The Journal of Biological Chemistry, 270, 23189-23195. 

In support of a role for androgens in sexual behavior is the finding that sexual interest or motivation is low in prepubertal boys and in men with various forms of hypogonadism (Burris, et al., 1992). Androgen treatments are typically associated with increased interest in sexual activities, as measured by self-report, as well as increases in nocturnal erections. However, increases in sexual behavior as a result of androgen treatments are less reliable, probably in part because men with a history of sexual inactivity may lack social skills or opportunities for sexual behavior. Social and historical variables, possibly also experienced as changes in other hormones, are critical determinants of masculine sexuality. 

Polyak, M. and Deans, J., Alanine-170 and proline-172 are critical determinants for extracellular CD20 epitopes heterogeneity in the fine specificity of CD20 monoclonal antibodies is defined by additional requirements imposed by both amino acid sequence and quaternary structure. Blood, 99, 3256-3262, 2002. 

Until recently, there was little clear evidence that cannabis use was toxic to neurons. Cannabinoids have been shown to have a mix of neurotoxic and neuroprotective effects and mixed results have been found in different studies. Scallet (1991) points out significant methodological differences in the existing studies that influence their outcomes. Critical determinants of neurotoxicity are both age during exposure and duration of exposure. For example, cannabinoid administration was required for at least three months (8-10% of a rat s lifespan) to produce neurotoxic effects in peripubertal rodents. This is comparable to about three years exposure in rhesus monkeys and seven to ten years in humans. Reports of neurotoxicity in primates were inconsistent, with up to 12 months of daily exposure. Longer exposures have not yet been studied (Scallet 1991). 

The hypothesis that the intracellular DAG to ceramide ratio is a critical determinant in the fate of cells towards cell division, cell cycle arrest or cell death (Figure 4) was recently tested in a T lymphocyte model (Flores et al. 

The effectiveness of the membrane in a certain application depends on the detailed morphology and microstructure of the membrane system, in addition to the performance of the above mentioned physicochemical mechanisms. These are critically determined by the synthesis process and this is why details of the preparation procedures are so important. The most important and well developed of these procedures are treated in Sections 13-2.9. 

To be sure of our terms dose and its duration are the critical determinants of the potential for toxicity. Exposure creates the dose. In our example, people are exposed to TCE through the medium of their drinking water, and receive a dose of TCE by the oral route. 

The two ultimate sources of chemicals - nature and industrial and laboratory synthesis - are then briefly described. This review sets the stage for a discussion of how human beings become exposed to chemicals. The conditions of human exposure are a critical determinant of whether and how a chemical will produce injury or disease, so the discussion of chemical sources and exposures naturally leads to the major subject of the book - the science of toxicology. 

Meil and See 1996 Self and Nestler 1988 Stewart 1983), and may become critical determinants of reinforcement of drug-taking behavior by nicotine administration. 

Evidence from the tobacco industry documents, from research studies that measure free-base directly in tobacco smoke particulate, and from examination of smokeless tobacco products, all show that the level of free-base nicotine as delivered to the tobacco user is a critical variable in the acceptance of tobacco products and their continued use. The physiological impact of the rapid delivery of nicotine in the free-base form is a critical determinant of continued nicotine-seeking behavior, with the unintended consequences of exposure to the other toxic components of tobacco smoke and smokeless tobacco. Evaluating total delivered nicotine alone is not sufficient to characterize product differences. To fully understand the influence nicotine has on the allure of these products, both total and free-nicotine levels must be measured. A comprehensive understanding of nicotine delivery is needed to help find effective means for breaking its addictive nature and, ultimately, in reducing the morbidity and mortality associated with tobacco use. The levels of free-base nicotine must be included as part of any effort to achieve a better understanding of how tobacco products themselves influence their continued use. 

Yang et al. (1992a, b) also utilised a combination of experiment and calculation to critically determine the phase region for the /9-NiAl, 7 -Ni3AI and j0 -Ni2AlTi phases. The philosophy of their approach was to produce an alloy with high levels of /3 and 0, as mixtures of these phases had been shown to have enhanced creep resistance in comparison to the monolithic phases themselves (Polvani et al. 1976). The combination of experiment and calculated phase % vs temperature plots (Figs. 

Pramlintide delays absorption of concomitantly administered drugs Pramlintide has the potential to delay the absorption of coadministered oral medications. When the rapid onset of an orally coadministered agent is a critical determinant of effectiveness (eg, analgesics), administer the agent at least 1 hour prior to or 2 hours after pramlintide injection. 

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