Human-plant interaction

Another approach that has been successful in the past, whether or not by design, is to let the millions of years of human-plant interaction do the work of the millions of tests. Aspirin was discovered when someone decided to see if there was anything to the old folk remedy of chewing on willow bark to relieve pain and of drinking willow bark tea to reduce fever. Quinine was discovered when a desperate monk gave a dying noble woman an extract of bark recommended to him by the indigenous... 

This volume treats pheromones (Chapters 4.01—4.06), defensive substances and toxins (Chapters 4.08—T. 10), antifeedants (Chapters 4.11-4.12), compounds employed in plant-plant and plant-microbe interactions (Chapter 4.13), plant-insect interactions (Chapter 4.14) and microbe-microbe interactions (Chapter 4.07). Hormones of plants (Chapter 4.02) and insects (Chapter 4.03) are also treated in this volume. A unique attempt in the present volume is to regard flavor and fragrance (Chapter 4.15) and taste (Chapter 4.16) as phenomena of human-environmental interactions or human chemical ecology. 

Errors made by humans when interacting with technical plants do not always have to impair them seriously. This is especially true for so-called fault-tolerant or fault-forgiving systems. Thus, only errors are of interest here which have detrimental consequences. 

The O SHA should review a host of plant activities and documentation. Review the various operational and maintenance procedures look at the mental and physical demands placed on the operators. Verify that the timing of procedures and operations is realistic. Section 8.2 goes into more detail about how to model human-machine interactions. 

After the task analysis forms have been filled out, you may wish to develop an operational sequence diagram. This is a graphical depiction of human-machine interactions and decision-making flow in the performance of a task over time. Because this graphical system representation is so labor intensive, it should be used only for very complex systems, such as nuclear power plant operations. 

The real problem is that the results may not give you sufficient data to solve your safety problems efficiently. Performing hazard analyses on a power plant operation without looking at how the human operators interact is one such example. You also may spend more time and money than you really needed to spend. 

Given that there is a hazard present, are there any human interactions with the plant that could cause the harm potential to be released ... 

Information on the types of human interactions with hazardous systems that occur would be obtained from sources such as plant operating instructions, job safety analyses and similar sources. These interactions are referred to as critical tasks (CT). 

PROBLEM DEFINITION. This is achieved through plant visits and discussions with risk analysts. In the usual application of THERP, the scenarios of interest are defined by the hardware orientated risk analyst, who would specify critical tasks (such as performing emergency actions) in scenarios such as major fires or gas releases. Thus, the analysis is usually driven by the needs of the hardware assessment to consider specific human errors in predefined, potentially high-risk scenarios. This is in contrast to the qualitative error prediction methodology described in Section 5.5, where all interactions by the operator with critical systems are considered from the point of view of their risk potential. 

The Chemical Process Industry (CPI) uses various quantitative and qualitative techniques to assess the reliability and risk of process equipment, process systems, and chemical manufacturing operations. These techniques identify the interactions of equipment, systems, and persons that have potentially undesirable consequences. In the case of reliability analyses, the undesirable consequences (e.g., plant shutdown, excessive downtime, or production of off-specification product) are those incidents which reduce system profitability through loss of production and increased maintenance costs. In the case of risk analyses, the primary concerns are human injuries, environmental impacts, and system damage caused by occurrence of fires, explosions, toxic material releases, and related hazards. Quantification of risk in terms of the severity of the consequences and the likelihood of occurrence provides the manager of the system with an important decisionmaking tool. By using the results of a quantitative risk analysis, we are better able to answer such questions as, Which of several candidate systems poses the least risk Are risk reduction modifications necessary and What modifications would be most effective in reducing risk ... 

Amphotericin B, is a polyene antibiotic, used in the therapy of systemic fungal infections. Its mode of action exploits differences in membrane composition between the pathogen and the human host. Ergosterol, the predominant sterol of fungi, plants, and some protozoan parasites, interacts with Amphotericin B, resulting in an increased ion permeability of the membrane. Humans contain cholesterol, which has a low affinity for amphotericin B. 

The second major difficulty is that cells and tissues in the body are exposed to numerous metabolites displaying different structures compared to the parent molecules present in plant foods. For example, it has been suggested that the metabolites of lycopene may be responsible for reducing the risk of developing prostate cancer. These metabolites may interact with nuclear receptors such as PPARs, LXR, and others. " Future research is needed to produce metabolites (enzymatically or chemically) in order to elucidate their cellular mechanisms and thus clarify their effects on human health. 

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