Doping violation

It appears that doping is becoming more and more important in modem sports, or at least the mtmber of athletes sanctioned for doping violations and the time devoted by the international media to these cases are on the rise. In a few high-profile cases, however, doubts also surface about the scientific background of prohibiting certain substances or the reliability of the methods used to detect them. 

In terms of the threshold-substance 5a-estran-3a-ol-17-one (NorA), several aspects need consideration, e.g., pregnancy and bacterial activity. Urinary levels > 2ng/mL represent doping violations, but several studies outlined the elevated production and elimination of NorA throughout gestation as well as the possibility to form NorA from A by demethylation. Hence, careful interpretations of steroid profiles and tests for bacterial activity (for instance, by means of deuterium-labeled A) are carried out. 

Ozone attack on the oxidatively violated rubber surface is thus prevented (21, 27, 29, 30). Creation of the surface layer was confirmed using microscopy. The theory is in agreement with the observation that the initial rapid ozone consumption is stabilized rubber drops and may be renewed after mechanical break of the formed film 21). There is a chemical proof of the theory. Ozonation products of N,N -bis(l-methylheptyl)-l,4-PD (DOPPD) form a surface film on ozonized and DOPPD doped vulcanized NR (31) and carbon-black loaded NR (24, 32). In addition to unreacted DOPPD, many of the low-molecular weight compounds observed in the film were found also in the ozonation of pure DOPPD (24) the only difference was a... 

If (5.20) is not valid other types of electrooptical effects take place and the modulated FVederiks transition cannot be observed in experiment. Figure 5.4 shows how doping liquid crystals with conducting and dielectric impurities can violate the inequality (5.20) and, consequently, the electro-hydrodynamic instabilities 1 and 5 (Table 5.1) are observed within the whole frequency range (curve B). Considerable change in the threshold voltage and inversion frequency also takes place for different values of the low-frequency dielectric anisotropy (curves A and C). 

Following the initial experiments by Kaiser, Axe (1964) extended the theories of Judd (1962) and Ofelt (1962) to calculate selection rules and intensities of two-photon transitions in solids doped with lanthanides. The theoretical predictions with later extensions by Bader and Gold (1968) laid largely untested as an hiatus occurred in the experimental studies in this area, the emphasis having shifted in this period to the observation of (4f) states buried in allowed (5d) or conduction bands. Interest has since returned following the work of Degenais (1981), Downer et al. (1982) and Down and Bivas (1983) on Gd " in LaFj. As noted in fig. 20, these workers observed a number of violations of the selection rules developed by Axe in both the intensity and polarization dependence and were able to trace the descrepancies to various approximations necessary in the... 

As opposed to doped matrices, for undiluted lanthanide salts the concentration can be so high that the linear relationship between absorbance and concentration no longer holds (violation of Beer s Law). If the two crystal faces through which the light beam... 

The utility of the detailed knowledge on the mass spectrometric behavior of steroidal agents was recently demonstrated when the combined information obtained from El and ESI-MS(/MS) experiments led to the successful identification of a long-term metabolite of metandienone,namely 18-nor-17p-hydroxymethyl,17a-methyl-androst-l,4,13-trien-3-one (Fig. 4.5, 11), which subsequently enabled the detection of more than 60 doping rule violations by elite athletes with metandienone. ... 

The category of 3-keto-4,9,ll-triene steroids has gained considerable attention due to the findings of numerous doping rule violations with compounds such as trenbolone, methyltrienolone, or tetrahydrogestri-none (Fig. 4.5, 14-16, respectively). Their principal fragmentation... 

With the obtained data, the desired AS C values are calculated and doping rule violations either verified or falsified. The formerly valid generic threshold of 3%o represented a means to identify suspicious differences in carbon isotope signatures of biosynthetic precursors and corresponding metabolites however, the customized thresholds for defined pairs of precursors/metabolites substantially enhance the level of confidence as well as the discrimination power of IRMS. 

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