Repetitive research reports

Research based on time-resolved XAS in an optical pump-x-ray probe scheme has first been implemented at synchrotron radiation sources. Mills et al. [2] used a 20 Hz repetition rate Nd YAG laser to photolyse carbonmonomyoglobin (MbCO) and monitor the photolysis product with time-resolved XAS around the K-edge of the iron atom. Other studies were carried out on different types of photolyzed systems in liquids, by Thiel et al. [3], Clozza et al. [4], Chance et al. [5,6] and Chen et al. [7,8,9]. All these studies were limited to the nanosecond or longer time domain. We recently reported on time-resolved XANES studies of a Ruthenium complex in water solution reaching the picosecond time scale [10]. This work allows us to evaluate the feasibility of future time-resolved XAS experiments, which we present below together with our new results. 

N-trifluoroacetyl amino acids have been reported as stable at -10°C over a 2-week period (53) and the TFA n-butyl esters are stable for about 72 hr when stored at 0 C in a nitrogen atmosphere (32). Reasonable stability of derivatives is necessary for repetitive analyses when many samples are prepared and stored prior to chromatography. Instability of silyl derivatives to hydrolysis has been a major problem which has led to decreased activity in research on these materials. The efficient treatment of amino acids with N,0-bis(trimethylsilyl)acetamide (51) and subsequent GLC of the derivatives is now used only occasionally as a result of instability of the derivatives. 

It is one of the fundamental requirements of research in the physical sciences that any observation reported in the literature should be capable of repetition anywhere at any time. Authors of scientific papers are therefore under an obligation to describe their materials and procedures in sufficient detail to make this possible. Nowhere is this requirement more necessary than in the field of heterogeneous catalysis, where, by reason of the complexity of the material used and the subtlety of the procedures applied in their pretreatment, the results obtained often depend critically on the variables involved. Full, detailed and accurate descriptions of what has been done are therefore needed, as it is sometimes the case that the really critical variable is not recognized by the operator, and is therefore not controlled. Such adequate descriptions are by no means always to be found in published work. 

It is safe to predict that most of the emphasis on analytical research on methods foy trace concentrations of anions in water during the next several years will continue to be on spectrophotometric chemical methods, and that interest in ion-selective electrodes for potentiometric analysis probably will continue to grow. It remains to be seen whether the scope of the latter method is limited. If these electrodes prove to be as simple and effective as reported, they may revolutionize the monitoring of water supplies and replace many chemical methods in situations where large numbers of repetitive analyses must be made. 

In 2006,1 made two similar studies, both for companies whose OSHA incident rates were well below average for their industries. Incident investigation reports on serious injuries only were sent to me for review. In one instance, 63% of serious injuries occurred to nonproduction personnel in the other study, 67%. Although the percentages fall within a narrow range, other research shows that such ratios are not found when the work requires intensive manual labor and when the work is highly repetitive and physically stressful. 

Shift work, its psychological effects and the fatigue associated with it, have also been the subject of intensive study by researchers such as Moore-Ede in the USA, and Wallace in Australia Repetitive tasks such as writers cramp have been reported on since a late nineteenth century sturfy of people working all day with quill pens. 

What I will do here is to provide a few central hypotheses for each objective in this book, mininfizing repetition as much as possible. However, the reader should recognize that these hypotheses were not formulated prior to actual experimentation since experimental results reported here have already been published. Furthermore, the reader will find that a number of these hypotheses are intuitively obvious, biased towards what I think are the central issues of this research, and represent provisional conclusions for this research, which may be true or may be false. Additional research will be required to ultimately determine which of these are tme (accepted) and which of these are false (rejected). We may tentatively assume them to be true until proven false. In spite of this, restating the objectives as hypotheses is constructive in that it provides an additional way of focusing on the central issues of the research described in this book. 

In this chapter, we first describe in greater detail the nosespace setup developed at the Nestle Research Center. We then discuss the variability among panelists as well as the in-mouth release variability for repetitions for the same person. Further interpretation of the effect of milk type and fat on nosespace release and the correlation with sensory intensity quantitation is reported in a separate publication (7). 

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