DESI

Like DART, DESI has received widespread acceptance as evidenced by more than 750 papers and conference presentations till mid-2014, referring to the technique since its introduction in 2004 by Cooks and coworkers [195, 196]. The technique makes use of electrospray ionization (ESI) that is widely used in the mass spec-trometiy of larger molecules in which a solution is nebulized to create a fine spray of very small droplets. In DESI, a standard electrospray of charged droplets hits the surface where the molecules of interest are present or adsorbed (including larger biomolecules), detaches them from the siuface, and delivers them as desolvated ions in the mass spectrometer. DESI is thus similar to DART (Sect. 8.4) where the gaseous plasma of ions from the ion source desorbs molecules from a surface. A schematic diagram of the main aspects of a DESI ion source is shown in Fig. 8.9. 

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Table 10.4-4. Overview of available programs for de novo desi ign.

FIG. 29-66 Oil-film hearing with oil pressure created preload (pressure dam desi nj. 

Example 8-29 Tray-to-Tkay Desi Multicomponent Mixture... 

Pressure Drop Desi Criteria and Guide Random Pacldi Only... 

On the other hand, the fluorine-induced addition of the diastereomeric silyl-subsliluted sulfides 36 A and 36B to benzaldehyde proceeds without loss of stereochemical information and with retention of configuration32. Since, however, the anionic reagent 35A/35B is known to be configurationally labile, the observed retention of configuration in the fluorine-induced desi-lylative hydroxy alkylation lends experimental evidence to the notion that these reactions proceed via hypervalent silicon species rather than anionic reagents. 

In the same study (Desi et al. 1998), no significant effects on these end points were seen in male rats exposed to methyl parathion only through the treatment of their dams during gestation or gestation and laetation these results are presented in Seetion 3.2.2.6. 

In the male offspring whose treatment was continued through 11-12 weeks of age, however, dose-related effects were seen on all the above end points, and these effects were significantly different from controls at all three dose levels (Desi et al. 1998) (see also Section S.2.2.4). The study did not determine the critical period (if any) and duration of exposure for these neurological effects. A limitation of this study is that results specifically for methyl parathion were shown only for the somatosensory electrocortico-gram the other results for this chemical were stated in the text, but not shown. 

ATSDR has derived an intermediate-duration oral MRL of. 0007 mg/kg/day for methyl parathion based on a minimal LOAEL of 0.22 mg/kg/day for electrophysiological effects in the central and peripheral nervous systems in rats (Desi et al. 1998). 

Desi I, Nagymajtenyi L, Papp A, et al. 1998. Experimental model studies of pesticide exposure. Neurotoxicology 19 611-616. 

Institoris L, Siroki O, Desi I. 1995. Immunotoxicity study of repeated small doses of dimethoate and methyl parathion administered to rats over three generations. Hum Exp Toxicol 14 879-883. 

Nagymajtenyi L, Schulz H, Desi I. 1995. Changes in EEG of freely-moving rats caused by three-generation organophosphate treatment. Arch Toxicol 17 (Supp) 288-294. 

Other additional studies or pertinent information that lend sunnort to this MRL Methyl parathion affects the nervous system by inhibiting acetylcholinesterase activity. Cholinesterase inhibition and neurological effects have been observed in humans and animals, for all exposure routes and durations (for example. Dean et al. 1984 Desi et al. 1998 EPA 1978e Gupta et al. 1985 Nemec et al. 1968 Suba 1984). 

Kracht, Th., SPECTRA, Technische Notiz, DESY/HASYLAB 94-01, 1994. 

Figure 4.4. Proposed design of the future European XFEL Facility in Hamburg extending from DESY to laboratories in Schenefeld 4 km East. The linear tube is split into a bunch of X-ray beamlines... 

Figure 2.1 Mass spectrometric approach. Dl, direct inlet GC, gas chromatography HPLC, high performance liquid chromatography CZE, capillary zone electrophoresis El, electron ionization Cl, chemical ionization ESI, electrospray ionization DESI, desorption electrospray ionization APCI, atmospheric pressure chemical ionization MALDI, matrix assisted laser desorption ionization B, magnetic analyzer E, electrostatic analyzer...

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