Experiment planning steps

The iteration of steps 1 to 3 provides a new information flux coming from planned experiments leading to a progressive reduction of uncertainty region (as demonstrated in several applications [3,4]). Flowever, note that each experiment design step is performed at the initial values of model parameters, and the uncertainty of these values, as reported in the literature [5], can deeply affect the efficiency of the design procedure. 

Finally, consider the number of steps that are feasible for the planned experiment because steps reflect the complexity of the experiment. The number of steps will be largely determined by the answers to the questions. Simple experiments involve two antibody incubations, each followed by four buffer rinses for a total of ten steps over 1 day. Complex experiments can involve six to eight antibody incubations, each followed by four buffer rinses for a total of 30 steps over 3 days. Consider the number of steps as a way to assess whether the complexity of the selected method is... 

Process-planning steps were introduced in the previous section. This section discusses the tools used to carry out these steps. Manual process planning, which relies on human experience, will not be discussed. The tools discussed in this section are those used in computer-aided process-planning systems. They are used to assist the human planner in developing process plans. Most of these tools have been used in practical process-planning systems. Methodologies or algorithms used only in advanced research will not be introduced here. 

The steps to be considered in planning an experiment can be described by a flowchart such as the one depicted in Figure 1.2. (section l.G), which shows the individual steps in a lahoratory expaiment. These steps, in turn, correspond to the different chapters of this book. For the experienced laboratory worko", these steps are understood intuitively, and the pre-experiment review is primarily a thought process, with perhaps a brief written description of the experiment plan. For others, the review of some or all steps on such a flowchart (and the corresponding chapters in this book), along with a more formal documentation process, is in order. 

Regulations are an intrinsic part of modern laboratory work that cannot be separated easily from other matters and should be considered at each step of experiment planning. It is only prudent for laboratory workers and supervisors to ensure regulatory compliance in conducting laboratory experiments. However, the responsibility of leadership goes beyond compliance to the protection of individual laboratory workers. 

Nevertheless, chemists have been planning their reactions for more than a century now, and each day they run hundreds of thousands of reactions with high degrees of selectivity and yield. The secret to success lies in the fact that chemists can build on a vast body of experience accumulated over more than a hundred years of performing millions of chemical reactions under carefully controlled conditions. Series of experiments were analyzed for the essential features determining the course of a reaction, and models were built to order the observations into a conceptual framework that could be used to make predictions by analogy. Furthermore, careful experiments were planned to analyze the individual steps of a reaction so as to elucidate its mechanism. 

The need for skill and experience on the part of sample designers and persoimel cannot be overemphasized in chemical plant sampling. Safety precautions are of the utmost importance. Necessary steps must be taken to document the hazards involved in an operation and to ensure that the staff are weU-trained, informed, protected, and capable. Except for bulk powder sampling, most chemical plant sampling is hazardous and difficult and must be designed with care. The following discussions are based on the assumptions that most of these decisions have been made and a satisfactory sampling procedure has been planned. 

It is a common experience in synthetic chemistry that a truly optimal ordering of a synthetic route may not be possible in the planning stage, but may have to determined experimentally. The precise information necessary for the complete and unambiguous evaluation of each step in a possible synthesis is hardly ever available. Nonetheless it is clearly wise to try to optimize a synthetic plan on the basis of available information before the experimental approach begins. Such an effort may suggest certain preliminary or "model" experiments that can be helpful in the choice or refinement of a synthetic plan. It is also obviously desirable to devise and consider alternate or bypass paths for each problematic step of a synthetic sequence. 

The breakdown of the job into steps is based upon personal experience of the planner or from history or standard job plans. Depending upon the job and skill level of the craftsman, it may require one activity or one hundred. Highly skilled mechanics may require a higher degree of instruction in the plan or how to complete the job, as well as closer supervision and support during job execution. 

In order for us to effectively develop and use these new tools, we must make the transition from an empirical, retrospective use of modeling to a planned design approach. The question to be addressed should not be Why didn t this experiment work Rather, we need a prospective outlook Can this work These new theoretical tools should be bringing new information to the chemist to be used in conjunction with experimental data already available. The success of computer aided design of chemicals will arrive when a chemist can sit at the terminal as the first step in the development process. 

As alluded to at the beginning of this section, traditional Minnesota-model treatment merges the disease model with the spiritual model. Since within this model the disease has no known cure, a spiritual solution has taken on importance. Because of this, disease-model counselors refer people to 12-step support groups for continued recovery. Some treatment centers even have spiritual counselors who work with clients on spiritually related goals listed in the treatment plan. This arrangement provides a great service to the many people with drug problems who have spiritual doubts or problems. However, it has been my experience that not everyone who enters treatment feels he or she has a spiritual problem. 

Eor every microarray experiment the first and most important step is experimental design. A badly designed experiment can render microarray data unsuitable for addressing the experimental questions or worse, lead the investigator to draw false conclusions. Furthermore, failed microarray experiments can be very costly both in terms of resources and time. There are many issues that must be addressed when planning a cDNA microarray experiment, some intuitive, others requiring considerable thought. 

Meanwhile, the Agency has been administering enforcement of the standard since March 27, 1980(13). Textile mills have been attempting to meet the various transitional steps required by the standard under the watchful eyes of the OSHA regional administrators and state OSHA plan administrators. This enforcement experience has revealed shortcomings in the standard difficult, if not Impossible, to enforce. These defects are itemized briefly below in two basic categories. 

Each group of experiments should be pre-planned. Perhaps multiple batch experiments, semi-batch or both can be conveniently used. The initial conditions for the batch runs and the steps of the semi-batch runs can be chosen randomly or in a judicious manner. The really important issue is that the mole ratios of any two reagents should never be held constant in a group this constitutes a co-linearity induced by the experimentalist. It can be noted that each perturbation in a semibatch experiment limits the future accessible region of composition space so planning is advisable. 

---