Identification confidence level

Because these bottom-up proteomic approaches are conducted in a data-dependent mode, it is foreseeable that other p-lactamases can be identified. In addition, an increase in the detection and identification confidence level is accomplished by the detection of mnlhple pephdes per protein. The discovery of unique pephde bio-... 

The distinction between detection and identification is important, since it may affect the overall response time and options. A detection occurs when a chosen parameter exceeds its threshold value. The detection may be nonspecific—that is, it registers the occurrence of an anomaly but does not necessarily indicate the presence of a particular threat substance. By contrast, identification establishes the identity of the threat substances in a given set. Nonspecific detection systems may have a relatively rapid response time compared with that of specific identification systems, but the former typically provide a lower confidence level that a threat substance is in fact present. In some cases, an alarm from a rapid but nonspecific detection system may be used... 

Figure 9.1a reporting GC-MS results taken on laboratory blank in a GC-MS procedure [87] shows negligible amino acid contamination. Indeed, quantitating a protein as the sum of 14 amino acids, a value of about 200 ng is the minimum required threshold to positively consider the protein identification. Figure 9. lb reports the chromatogram of an amino acid standard solution acquired in the SIM mode and corresponds to the quantitation limit that is a content of about 700 ng in the sample at a confidence level of 95%. This seems amenable when working at the trace level. 

The results of data treatment are documented and evaluated in ES 5 and the interpretation in ES 6 is guided by the analyst s constraints and requirements. For instance, simple visual pattern comparisions may be acceptable for sample identification, or a combined database (GC-FTIR/GC-MS), (PGC/FTIR), (GC/TA), etc., analysis may be required. Judgmental decisions must be trained into the system as to depth of analysis, its acceptability and reliability (e.g., the hit quality index (HQI) of the MS search combined with that from the FTIR search may confirm within a 95% confidence level the GC peak or sample identity). 

Table 16.5 General structure of a sulfa drug, structure of five sulfa drugs containing six-mem-bered heterocyclic R substituents, and measured pK values pK values were calculated using a spectrophotometric titration. Errors represent the 95% confidence levels and both the values and the associated errors were obtained from fits of the data using Scientist for Windows. Reprinted with permission from Boreen AL, Arnold WA, McNeil K (2005) Triplet-sensitized photodegradation of sulfa drugs containing six-membered heterocyclic groups identification of an S02 extrusion photoproduct. Environ Sci Technol 39 3630-3638. Copyright 2005 American Chemical Society...

In Figure 8.14, the Cold El mass spectrum of corticosterone in methanol solution is shown in the upper trace, and is compared with the standard NIST 98 El library mass spectrum shown in the lower trace. Note the similarity of the library mass spectrum to that obtained with the SMB apparatus. All the major high mass ions of m/z 227, 251, 269, and 315 are with practically identical relative intensity and thus good library search results are enabled with the NIST library-matching factor of 829, and the reversed matching factor of 854% and 86.5% confidence level (probability) in corticosterone identification. In addition, the molecular ion at m/z 346 is now clearly observed while it is practically missing in the library (very small in the shown mass spectrum and absent in the other three replicate mass spectra). 

Table 1 shows the range of BET surface areas (from 2 replicates of each catalyst) for all 8 specimens. Yates analysis was used to obtain the variance estimates associated with the relevant effects given in the effect identification column. The sign of the variance is a reflection of the direction of the effect. It is seen that the interaction between time and the H2 C3Hg ratio has the smallest variance estimate. F-values for other effects were calculated using the smallest variance as the denominator as shown in the last column. From standard tables, F44 at 95% confidence level is 6.39, this immediately suggest that the statistically-... 

Based on standard assays, such as an Ames test, the predictions for each endpoint are presented with qualitative confidence levels for positive results. Confidence is expressed as, for example, plausible or equivocal in association with a particular alert and can be modulated, for example, to probable , reflecting identification of actual data on the query chemical (a matching... 

Overall, the use of a Q-TRAP Instrument with IDA demonstrated powerful capabilities of high throughput quality data acquisition. APEX metabolite identification examines the isotope patterns of the targeted ions to give more accurate results, increasing the confidence level of the automation. Meteor showed satisfactory prediction abilities that could be improved with more knowledge about more complicated or combined biotransformation pathways. In fact, in Meteor (version 12, the current version), version, M3 is predicted, albeit via the reverse mechanism to the one proposed i.e. aromatic ring... 

Data coded Reading Increment" (LRI). The value of T is usually 5 times W. Larger factors of 10 or 20 times W are used for methods subject to greater uncertainty in target analyte identification or quantitation. Because W is usually approximately 2/3 of the standard deviation, T (=5W) will exceed the 95% confidence level for detection of analyte in the sample, and will often be essentially equivalent to the 3s detection limit. 

Statistical analysis of the simulation parameters, which allows the identification of simultaneous confidence regions at specific confident levels... 

Tactical Situational Awareness (e.g. identification tactical status type capabilities location threat flight dynamics own capabilities relative to threat threat detections threat launch capabilities threat prioritisation threat imminence and assignments current and projected intentions, tactics, firing, manoeuvring mission timing and status confidence level of information etc.)... 

Identification criteria are neither absolute nor arbitrary they arise from the level of identification confidence that is considered acceptable for a given application. 

Current attempts to derive such a scheme are discussed below, but the ultimate aim would be to develop such criteria to the point where the appropriate Null Hypothesis (see Section 8.2.4), i.e., [H the experimental data for compound identification in the analytical sample and for the standard are indistinguishable] can be affirmed with a defensible confidence level. As was emphasized previously (Bethem 2003), all that science can do is show that the alternative hypothesis [H, the two sets of data are statistically different] is highly improbable. In other words, the scientific method does not claim to be able to prove absolutely that one or other of the opposing hypotheses (appropriately expressed, by no means a trivial task in this case) is valid. If Hj is accepted on the basis of the currently available data, this does not mean that the suspected analyte has been confirmed as not present, only that it can not be proved to be present at a preagreed confidence level based on the available data. There is always some probability (however low) that a negative result can be changed to positive as a result of additional data acquired in the future, or that a positive identification might have arisen as a result of the presence of some hitherto unknown compound or some unsuspected scientific or technical phenomenon. 

Fialkov, A.B., Amirav, A. (2003) Cluster chemical ionization for improved confidence level in sample identification by gas chromatography/mass spectrometry. Rapid Commun. Mass Spectrom., 17(12), 1326-1338. 

Technique Automation Selectivity Confidence level Speed Flexibility Polymer identification Additive identification... 

Note In this case, only highly expressed ribosomal proteins are included in the in silico generated biomarker database. Results scale to a database of 1000 organisms at 95% confidence level of identification. 

Extended Plant-Performance Triangle The historical representation of plant-performance analysis in Fig. 30-1 misses one of the principal a ects identification. Identification establishes troubleshooting hypotheses and measurements that will support the level of confidence required in the resultant model (i.e., which measurements will be most beneficial). Unfortunately, the relative impact of the measurements on the desired end use of the analysis is frequently overlooked. The most important technical step in the analysis procedures is to identify which measurements should be made. This is one of the roles of the plant-performance engineer. Figure 30-3 includes identification in the plant-performance triangle. 

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