S-delay

OS 44] ]R 4a] ]P 33] 4-Bromobenzonitrile plugs (5 s) were inserted into a continuous phenylboronic acid stream for time intervals of5,15,25, 30,40 and 55 s (25 min reaction period) [6, 7]. For a 5-20 s delay, catalyst saturation occurs owing to the high injection rates rendering the phenylboronic acid concentration too low. In turn, for delay times of 30-55 s, the effective concentration of 4-bromobenzonitrile becomes too low. At 25 s, optimum performance with a yield of 62% was achieved (Figure 4.67). 

Figure 17. Contour plot of the 360MHz homonuclear spin correlation mpa of 10 (2 mg, CDCL, high-field expansion) with no delay inserted in the pulse sequence shown at the top of the figure. Assignments of cross peaks indicating coupled spins in the E-ring are shown with tljie dotted lines. The corresponding region of the one-dimensional H NMR spectra is provided on the abscissa. The 2-D correlation map is composed of 128 x 512 data point spectra, each composed of 16 transients. A 4-s delay was allowed between each pulse sequence (T ) and t was incremented by 554s. Data was acquired with quadrature phase detection in both dimensions, zero filled in the t dimension, and the final 256 x 256 data was symmetrized. Total time of the experiment was 2.31 h (17).

Figure 18. A 0.2-s delayed COSY spectrum of the aliphatic region of 10 (2mg, CDCLj). Long-range "W-type" coupling of 19 and 21 axial protons to 30-CHj and coupling across the gem dimethyls from I9eq to 21 eq establish the position of oxidation at C-22. The spectrum was obtained under conditions similar to those in Figure 1, except that 32 transients were acquired for each of 128 x 512 data point spectra (17).

The 50.31 MHz 13C NMR spectra of the chlorinated alkanes were recorded on a Varian XL-200 NMR spectrometer. The temperature for all measurements was 50 ° C. It was necessary to record 10 scans at each sampling point as the reduction proceeded. A delay of 30 s was employed between each scan. In order to verify the quantitative nature of the NMR data, carbon-13 Tj data were recorded for all materials using the standard 1800 - r -90 ° inversion-recovery sequence. Relaxation data were obtained on (n-Bu)3SnH, (n-Bu)3SnCl, DCP, TCH, pentane, and heptane under the same solvent and temperature conditions used in the reduction experiments. In addition, relaxation measurements were carried out on partially reduced (70%) samples of DCP and TCH in order to obtain T data on 2-chloropentane, 2,4-dichloroheptane, 2,6-dichloroheptane, 4-chloroheptane, and 2-chloroheptane. The results of these measurements are presented in Table II. In the NMR analysis of the chloroalkane reductions, we measured the intensity of carbon nuclei with T values such that a delay time of 30 s represents at least 3 Tj. The only exception to this is heptane where the shortest T[ is 12.3 s (delay = 2.5 ). However, the error generated would be less than 10%, and, in addition, heptane concentration can also be obtained by product difference measurements in the TCH reduction. Measurements of the nuclear Overhauser enhancement (NOE) for carbon nuclei in the model compounds indicate uniform and full enhancements for those nuclei used in the quantitative measurements. Table II also contains the chemical... 

Figure 7.25 STM image sequential (55 s delay) 200Ax 115 A images of Rh(l 1 1) with 0.50Torr CO and 0.92Torr NO (/ = 260pA, V=50mV). The top arrow shows one top site occupied by NO in the top image and by CO in the bottom one. The bottom arrow shows the opposite.

It explodes at 394°, and the copper salt at 371°C, each after a 10 s delay. They are not impact-sensitive. 

As the anhydride of nitrous and perchloric acids, it is a very powerful oxidant. Pinene explodes sharply acetone and ethanol ignite, then explode ether evolves gas, then explodes after a few s delay. Small amounts of primary aromatic amines-aniline, toluidines, xylidines, mesidine-ignite on contact, while larger amounts exploded dangerously, probably owing to rapid formation of diazonium perchlorates. Urea ignites on stirring with the perchlorate, (probably for a similar reason). 

The residues from a cortisol assay procedure (5 cc dichloromethane, 2.5 cc of a fluorescent reagent in 15 85 ethanol-sulfuric acid) were added to a 500 cc bottle and screw capped. After a 90 s delay, the bottle burst violently and brown fumes were seen. It was surmised that a nitrate or nitrite contaminant in the bottle had... 

Figure 12 Comparison of Vch artefacts intensity illustrated with ID rows taken from a BIRD-HMBC (A), (D) and (G) a G-BIRD-HMBC (B), (E) and (H) and a double tuned G-BIRD-HMBC (C), (F) and (I) experiments showing the Vch artefacts and nJCH responses of C-6 at 135.6 ppm (A), (B) and (C), C-l at 67.2 ppm (D), (E) and (F) and C-10 at 27 ppm (G), (H) and (I) of the 1,3-butadiynyl (tert-butyl) diphenylsilane molecule dissolved in CDCl3. For the BIRD-HMBC and G-BIRD-HMBC experiments, the delays S were adjusted to aV-value of 190 Hz, as an average value for the extreme range of coupling constants for this molecule (125-260 Hz). For the double tuned G-BIRD-HMBC, the /ch nnax and /ch nnin values were set to 240 and 145 Hz, respectively. The corresponding values for the S and S delays were 3.13 and 2.17 ms, adjusted toj values of 160 and 230 Hz, respectively. For both G-BIRD-HMBC experiments, 192 is BIP 720-100-10 pulses have been used for 13C inversion. The same vertical scale is used for all spectra. Residual /ch signals are denoted with arrows.

Burdjga There is always a delay between the Ca2+ rise and initiation of the mechanical activity. Tom Bolton reported a 1 s delay between the rise of Ca2+ and cell shortening. In intact preparations the delay is a maximum of 300 ms. This is something to think about when we are talking about localized and global events and translating them into functional responses. 

The crude 2-aminothiazoles were dissolved in DMSO-d6 (2 mL). A reference solution of p-dimcthoxybcnzcne in DMSO-d6 (2M, 50 pL) was added to each of the samples, and proton NMR spectra were recorded. A 5 s delay was added between scans. The amount of 2-aminothiazole present was determined by a comparison of integral peak heights of the 2-aminothiazole and the reference compound. 

As stated previously (pp. 62 etseq.) there is often correlation between anticholinesterase activity in vitro and gross mammalian toxicity. The toxicity of O.M.P.A. is not very muoh less than that of tabun, D.F.P. and T.E.P.P., yet the anti-cholinesterase activity of O.M.P.A. in vitro is negligible (50 per cent inhibition, 4-5x10 2m). On the other hand, O.M.P.A. produces all the symptoms of acetylcholine poisoning when administered to animals. Moreover, the serum cholinesterase of such animals is almost completely inhibited. Another anomaly of O.M.P.A. is that toxic action is slower than that of D.F.P. or tabun, an hour s delay being usual compared to the very quick knock-out action of D.F.P., etc. (see p. 2). 

After washout, edotecarin or SN-38 produced analogue cell-cycle perturbations after 7 hours of recovery (G and S delay). While in blocked cells after treatment with edotecarin, effects persisted up to 24 hours of 30 nM and up to 72 hours at 300 nM, whereas cells treated with SN-38 at both doses restarted cycling after 24 hours of recovery. 

NOE Measurements. The one-dimensional NOE data were collected at 300 MHz on a Bruker AM-300 NMR spectrometer operating at 300 K. Because the relaxation times for the protons of the hexa-deuterated compound ranged from O.A s to 3.8 s, delays of 20 s. were used between scans. Values for the T s were also measured and found to range from 0.32 s to 1.5 s all values were consistent with a rotational correlation time of 1.1x10 s. 

Atkinson, W.S. Delayed keratitis due to mustard gas (dichloro-diethyl sulfide burns). Arch. Ophthalmol. 40 291-301, 1948. 

DuPont s Delay Electric Caps, such as Acudet Mark V and MS (Millisecond) Delay (Ref 6, pp9l DuPont s Detaclad (Explosion-Bonded Clad Metal), Ref 6, op 14-15. See also Vol 3 of Encycl, p D96-L... 

J. P. Vigier, EPR version of Wheeler s delayed choice experiment, in Microphysical Reality and Quantum Formalism, ISBN 9-02-772686-8, Kluwer, Dordrecht, 1988. 

Hence another strategy was followed, where the calibration is done by means of a solution from the detection cell. With this solution, the sensor signal, as well as the concentration of hydrogen peroxide through titration, was obtained. In order to be able to calculate subsequently the original concentration in the bath where the process occurs, the dilution factor should be taken into account, and for the control of the hydrogen peroxide concentration one should bear in mind a 30-s delay. In this way, a possible difference in process-bath composition is eliminated. The equation for the calculation of the hydrogen peroxide concentration in the process bath is ... 

Monsigny, M., Quetard, C., Bourgerie, S., Delay, D., Pichon, C., Midoux, P. et al. (1998) Glycotargeting the preparation of glyco-amino acids and derivatives from unprotected reducing sugars. Biochimie, 80, 99-108. 

FIGURE 4.25 Sequences of nine consecutive pressure pulse injections with 4-s delay using a mixture of 38 iM calcein and 19 iM fluorescein (a). Species B, C, and D are derived from calcein. The durations of pressure pulse are (a) 0.3, (b) 0.35, and (c) 0.4 s [314]. Reprinted with permission from the American Chemical Society. 

FIGURE 32. 29Si—29Si 2D INADEQUATE CR spectmm of the dendritic polysilane tris[2,2,5, 5-tetrakis(trimethylsilyl)hexasilyl]methylsilane measured at 99.300 MHz (70 mg of the sample in CDCI3 256 transients in 75 h, acquisition time 0.203 s, delays x and S not given). Reproduced by permission of John Wiley Sons, Ltd from Reference 243... 

Fig. 3.8. Graph demonstrating that the perfusion threshold for mismatch tissue to be salvaged from infarction declines with time. These patients all had major reperfusion on follow-up imaging and tissue with severe hypoperfusion (mean transit time 15-s delay) was able to be salvaged from infarction within 3 h, but at 6 h, the threshold for salvage declined to only 3 s delay in mean transit time (Butcher et al. 2003)...

So far we have not included the relaxation processes (T and 72), and for many pulse sequences we can leave out this aspect to make the math simpler. We know that relaxation is going on, but in many cases this is merely a technicality and is not essential in understanding the pulse sequence. In general, pulses are on the timescale of microseconds (p,s), delays for evolution are on the order of milliseconds (ms), and delays for buildup of NOE can be hundreds of ms. For organic-sized molecules, we can safely ignore relaxation for delays in the [is or ms range. Of course, for some experiments such as NOE, the relaxation process is central to the experiment so we cannot ignore it. 

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