Study responsibilities

Exposures resulting in nonlethal, irreversible effects of dimethylhydrazine were not well defined. For most studies, responses were described in terms of no visible signs of toxicity or lethality. However, Weeks et al. (1963) described nonlethal (but reversible) effects in dogs exposed to 1,1-dimethylhydrazine at varying concentrations. In this study, dogs were exposed to 1,1-dimethylhydrazine at 1,550 ppm or 4,230 ppm for 5 min or 360, 400, or 1,530 ppm for 15 min. The highest cumulative exposures at each of two exposure periods (Ct =352-383 ppm-h) were associated with marked tremors, convulsions and death, while the lower concentration exposures at each of two periods caused behav... 

A statistical significant effect is not always relevant from the practical point of view. Therefore, a worst-case level combination experiment with regard to the studied response (e.g., resolution) is determined and performed with replicates. In this experiment, only the method parameters with major effects (both statistically significant and almost significant) are considered. As can be seen in Figure 15, the major effect, temperature and pH, are easily detected. The worst-case combinations... 

FIGURE 8 Separation dashboard describing the influence of the factors on each of the studied responses based on the results of the Box Behnken design. The closeness to a target response that is aimed for each response in this study is represented by a desirability value (d). Reproduced with permission from reference 16. 

Studied responses were resolution, migration time, peak area or height, and drug content. 

Studied responses were resolution, " " analysis time, migration time, plate count, tailing factor, tablet content, peak area, peak height, peak width, and peak area/migration time ratio. ... 

Studied responses were resolution, " migration time, " concentration, ... 

Association study Response to Clozapine Nonresponse to Clozapine ... 

More common are case series and open trials of mood stabilizers for acute mania (see Davanzo and McCracken, 2000 for review). These studies, some of which were done in the 1970s and 1980s with classical adolescent manic patients, showed promise for the use of lithium in the treatment of mania. In some early studies, response to lithium was a requirement for diagnosis, a circular criterion that would undoubtedly have increased the response rate. 

A mathematical model was found for each studied response. From the models, the contoured curves and the response surfaces were plotted, and the optimal points were sought and confirmed. 

Melnick (11) has made the most extensive study of the slow photoconductive response. Using zinc oxide sintered in air, he has studied responses in the time range from 0.3 to 10 sec. 

We will present the basics of the simplex method with the aid of a simulation and then describe the algorithm. As an example, Soylak et al. [18] optimised a procedure to preconcentrate lead (the studied response, Y) using a 2 factorial design in which the factors were ... 

A researcher is therefore recommended to use the design of experiments or to achieve an optimum in an experimental way. A researcher who designs an experiment does not know beforehand where in the studied response surface the optimum is located and what the shape of the surface is. Therefore he uses two approaches to reach the optimum. By one approach, he approximates in the given experimental region his experimental data by an assumed empirical model, or fits the response surface to the degree of the needed polynomial accuracy. Based on such an analytical model, he performs analytical optimization. Reaching an optimum in this case is more efficient if the obtained analytical model is adequate. By another approach, the researcher does not form an analytical model, but he does his experiments iteratively by prior established rules until he reaches the optimum. 

Movement to optimum along the gradient is in steps from the starting point to optimum. Due to the necessary number of steps for reaching optimum, we differentiate several gradient methods that are in use nowadays. Efficiency of gradient methods depends on the complexity of the studied response space, on magnitude of the selected step, on size of experiment error and on other factors. 

In environmental studies, responses to the following questions are frequently required ... 

Metabolic studies Response to fasting (glucose, free fatty acids, acetoacetate, P-hydroxybutyrate), response to medium-chain triglycerides... 

In the first case, attention is paid to excluding variables carrying low or redundant information, in the second, to excluding variables which are not functionally related to the studied response. In the latter, besides the exclusion of specific variables, one can condense the information from all the original variables into a few significant latent variables (linear combinations) by methods such as Principal Component Regression and Partial Least Squares regression. 

Few studies have tested whether toxicants can bind to the RARs or RXRs, and most of these have only considered binding to human or mouse RA receptors48 70 92. Because mammalian and fish RA receptors have different binding specificities for compounds such as 4-OH RA3, the use of mammalian systems may not be a suitable surrogate for studying responses in fish. 

While there was a difference in performance for the bridging course students (students with the P module had improved performance) the small number of participants did not allow any conclusions to be drawn from this study alone. It did, however, support the view that students with a weak background in a domain may benefit from personalized teaching material. Despite the small number of BC students who participated in the study, responses in the module rating survey show that students in the P group found the module more helpful and engaging. 

There are ample self-made misconceptions regarding the formulation of reaction symbols. Mulford and Robinson [32] discovered the following situations regarding questions 5 and 6 (see Fig. 5.21) when evaluating the empirical studies Responses to question 5 suggest that students came to us with a very poor understanding of chemical formulas and equations. Only 11 % selected the correct answer d. When we consider the number of students who selected responses a, c and e, we see that 65% chose responses that do not conserve atoms. Combining responses a, b and e indicates that 74% appear not to understand the difference between the coefficient 2 and the subscript 3 in 2 S03 [32],... 

Swiss HIV Cohort Study, Response to antiretroviral treatment in HIV-l-infected individuals with allelic variants of the multidrug resistance transporter 1 a pharmacogenetics study. Lancet 2002 359(9300) 30-36. 

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