Collaborative study problems

Collaborative study problems related to methods and instmments. 

Whitbread, I. K. (1995), We are what we study Problems in communication and collaboration between ceramologists and archaeological scientists, in Lindahl A. and O. Stilborg (eds.), The Aim of Laboratory Analyses of Ceramic in Archaeology, Workshop Proc., KVHAA reprinted in Konferenser 34, 91-100. 

The previous chapters of this book have discussed the many activities which laboratories undertake to help ensure the quality of the analytical results that are produced. There are many aspects of quality assurance and quality control that analysts carry out on a day-to-day basis to help them produce reliable results. Control charts are used to monitor method performance and identify when problems have arisen, and Certified Reference Materials are used to evaluate any bias in the results produced. These activities are sometimes referred to as internal quality control (IQC). In addition to all of these activities, it is extremely useful for laboratories to obtain an independent check of their performance and to be able to compare their performance with that of other laboratories carrying out similar types of analyses. This is achieved by taking part in interlaboratory studies. There are two main types of interlaboratory studies, namely proficiency testing (PT) schemes and collaborative studies (also known as collaborative trials). 

Matsuura, M., Okubo, Y., Kato, M., Kojima, T, Takahashi, R., Asai, K., Asai, T, Endo, T, Yamada, S., Nakane, A., Kimura, K., and Suzuki, M. (1989) An epidemiological investigation of emotional and behavioral problems in primary school children in Japan the report of the first phase of a WHO collaborative study in Western Pacific Region. Sod Psychiatry Psychiatri Epidemio 24 17-22. 

Many standardized functional property tests have been published. Standardized methods are available from many organizations, including the American Association of Cereal Chemists, American Oil Chemists Society, and International Dairy Federation. Generally, these methods have been tested in collaborative studies by several laboratories and found to be repeatable. Therefore the use of standardized methods may facilitate comparison of results between laboratories. Even though a method has been standardized, there is no guarantee that the test results will relate to protein functionality in a particular product or product application. Another problem is that most of the standardized tests are empirical. If any step in the procedure is changed or equipment is substituted, comparisons between laboratories may not be possible. 

Overall there was good correlation observed between ELISA and TLC results for corn and roasted peanut products, with 93 and 98% correct responses for visual and instrumental determinations, respectively. In the case of raw peanuts, a significant number of false positive results was noted for the low level sample (<20 ppb), as well as an extremely high instrumental result. However, it was subsequently determined that sample handling problems with raw peanuts were the source of this problem. This has been addressed, and another followup collaborative study planned. For visual determination in the <20 ng/g sample, the RSD, (relative standard deviation within laboratory) and RSD, (relative standard deviation between laboratories) for corn were 38.5 and 60.7% and for roasted peanuts 73.7 and 73.7%, respectively. These are considerably higher than the instrumental results. On the basis of this study the AOAC adopted the method as... 

It is possible to take up the problem from the other end and to declare the reproducibility of the procedure, i.e. the interlaboratory standard deviation 5r, as the measurement uncertainty ( top down procedure). If the same analytical procedure is performed in numerous laboratories at the occasion of a collaborative study it... 

It is possible to take up the problem from the other end and to declare the reproducibility of the procedure, i.e. the inter-laboratory standard deviation jr, as the measurement uncertainty ( top-down procedure). If the same analytical procedure is performed in numerous laboratories at the occasion of a collaborative study it can be assumed that all possible influences add to the inter-laboratory standard deviation which finally is calculated from all data. If no interlaboratory test was performed, it is only the own intra-laboratory standard deviation which is known, a value that may be too small and thus too optimistic, especially when it is necessary to compare the own results with the ones from other laboratories (suppliers, customers, authorities, competitors). 

Very few collaborative studies between accredited doping laboratories are available to determine their variances. As such determinations are rather complex, some of the experimental parameters are most of the time left uncontrolled. Great attention should be given to standardization of the methods. Matrix problems are known during calibration and best results can be obtained with the systematic use of good quality deuterium-labeled internal standards. The... 

Other biological assays have been developed that avoid the sacrifice of animals. The mouse neuroblastoma assay measures PSTs by the survival of cultured neuroblastoma cells after addition of extract. In this assay, Na /K -ATPase inhibitor ouabain and the sodium channel activator verattidine are added to neuroblastoma cells prior to the addition of toxin extract. PSTs that are present in the extract prevent the veratridine-induced influx of sodium ions into the cells, and thus prevent cell death. A commercially available kit version of this assay, the MIST shippable cell bioassay kit [184], showed good agreement in a comparative study to the mouse bioassay [185] however, it performed unsatisfactorily in an AOAC international collaborative study in 1999, and there have been quality problems related to the shipping of the kit. The MIST kit was eventually replaced by the MIST Alert kit, which is an immunological assay that utilizes antibodies to STX, neoSTX, GTXl-4 [186]. Various other immunoassays exist [187]. 

Future development in GC-MS analysis will require the use of more stable GC capillary columns or multidimensional GG coupled to advanced MS techniques such as HRMS and MS-MS with El and EGNI ionization. The availability of further individual congeners for specific analysis and isotopically labeled standards will assure an accurate quantitative analysis. In addition, the development of more selective analytical methods for the isolation of these compounds from environmental and biological matrices can help to enhance the selectivity of the LRMS techniques. Further research and collaborative studies still need to be done to solve the problems associated with the analysis of PGTs and toxaphene. 

The probe molecules of greatest historical interest in catalysis are the Hammett indicators [13]. The difficulty of making reliable visual or spectrophotometric observations of the state of protonation of these species on solids is well known. We have recently carried out the first NMR studies of Hanunett indicators on solid acids [ 14]. This was also the occasion of the first detailed collaboration between the authors of this article, and theoretical methods proved to strongly compliment the NMR experiments. The Hanunett story is told after first reviewing the application of theoretical chemistry to such problems. Central to the application of any physical method in chemistry is the process of modeling the relationship between the observables and molecular structure. However often one does this, it is rarely an exact process. One can rationalize almost any trend in isotropic chemical shift as a function of some variation in molecular structure - after the fact, but the quantitative prediction of such trends in advance defies intuition in most nontrivial cases. Even though the NMR spectrum is a function... 

Our work on photochemistry was started in collaboration with Massimo Olivucci, and the study of electron transfer problems was initiated with Lluis Blancafort. However, our study of conical intersections has involved many other collaborators, postdocs, and students. Only some of their work has been cited explicitly here. However, articles such as this, which collect many ideas and thoughts, are possible only through the dedicated hard work of our co-workers over many years who helped to develop them. 

From his early youth, under his father s influence, K. H. Meyer had retained a keen interest in biological problems, as was evident from his study of the phenomena of narcosis, which he pursued during his stay in industry. As a natural consequence, he extended his thoughts to biological problems, and evolved a quantitative theory of muscular contraction (in collaboration with Picken), based on analogies with the elasticity of rubber. With J. F. Sievers, the permeability of synthetic membranes was investigated, and a mathematical treatment of the phenomenon was advanced which was later applied to living membranes. 

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