X-ray positive

The atomic dipole moment can be attributed to the preferential population of specific nonspherical atomic orbitals. In particular, this is the case for atoms with doubly-filled nonbonding lone-pair orbitals, such as the oxygen atoms in C—O—H and H—O—H, or oxygen in a terminal position as it is in the carbonyl group. An early demonstration of the bias introduced in X-ray positions of non-hydrogen atoms was the combined X-ray and neutron study of oxalic acid dihydrate (Coppens et al. 1969), which showed the X-ray positions of the oxygen atoms to be systematically displaced by small amounts into the direction of the lone pair density. 

Neutron diffraction is especially important for the location of hydrogen atoms, as the pronounced effect of bonding on the hydrogen-atom charge density leads to a systematic bias in the X-ray positions, as discussed in chapter 3. If the charge density in a hydrogen-containing molecule is to be studied, independent information on positions and thermal vibrations of the H atoms is invaluable. 

Figure 8. Probability map of the water positions obtained from the Monte Carlo simulation of cyclo(L-Ala-L-Pro-D-Phe)t. In this section the density for the two water molecules with two alternate positions 3 and 4 are shown. The x-ray positions are indicated by the circles within the density. Note the density spanning these, indicating that the water molecules oscillate between these positions during the...

Deferoxamine is an effective chelator of iron. Deferoxamine chelates iron and converts it to a water-soluble complex, ferrioxamine, which is eliminated readily via the urine. Indications for deferoxamine infusion include significant clinical signs of iron toxicity, metabolic acidosis, shock, serum iron levels >500pgdl , and/or an X-ray positive for multiple pills. Deferoxamine should be infused intravenously at a starting rate of 15mgkg h , not to exceed lgh , over a total of 6h and then reevaluated. Deferoxamine-induced hypotension may occur at fast rates, and adequate hydration should be assured before infusion initiation. As iron is chelated and excreted, urine may develop a characteristic rusty-red ( vin rose ) appearance. 

DEN 93] DENIARD P., EVAIN M., BARBET J.M., BREC R., The Inel x-ray position sensitive detector a study of d-spacing accuracy and exposure time . Mater. Sci. Forum, Trans. Tech. Publications, Switzerland, vol. 79-82, p. 363-370, 1993. 

Part of simulation ECEPP/2 vdW + electrostatic, hydrogen bonds, torsional potential e = 2 united-atom + polar hydrogens harmonic force on N, Ca, C, O atoms of terminal residues on x-ray positions... 

Atoms marked with asterisks arc fixed to deprolonated their X-ray positions 1 t JA)5 during... 

Fig. 18 One-component X-ray positive resist based on fBOC deprotection...

A useful review of X-ray position sensitive detectors is that of Arndt (1986). 

Scheme 7.31 One-component x-ray positive resist based on t-BOC deprotection.

Figure 2 Collecting coral cores. (A) Coral core being extracted from top and center of an individual massive coral head using a pneumatic coring device. (Photo courtesy of M. Kazmers/Shark Song Tax ID 374-50-5314.) (B) X-ray positive print reveals the banding pattern of the slab and is used to help establish a chronology for the entire coral record.

Simplistically, approval to market a drug could be based on one positive, adequate, and well-controlled phase III study supported by a phase II study where the endpoint was a surrogate endpoint marker. For example, if it is accepted that chest x-ray findings may be indicative of pulmonary function deterioration and the claim for the drug will be preservation of pulmonary function, one adequate and well-controlled phase III study with a pulmonary function endpoint supported by one phase II chest x-ray positive finding adequately fulfills the requirements of the act. 

X-ray tomography Very slow 0.02 X 0.02 X 2.0 mm Speed inversely proportional to size Penetrant dyes, low frequency X-rays Position of dense inclusions and surzface connected features... 

In looking at the discrepancies between the X-ray atomic positions, and those determined by neutron diffraction in the case of the oxide, the X-ray position of the oxygen is shifted relative to the neutron position as shown by the arrow in Figure 2.7 by 0.013(4) A. In the parent nitrile, the nitrile carbon positions are shifted (X ray relative to neutron) in the direction shown by the arrow by 0.0085(15) A. 

The most obvious alternative explanation of the observation is that there is an outer skin of crystalline material, due to the temperature gradient across the tape, which is giving rise to foe SAXS. In this situation the crystals formed would be well ordered and one would expect them to diffract at wide angles, which is obviously not foe case. Under foe current experimental conditions, it is p< sible to observe diffraction from 1% by volume of a crystalline olefin dispersed in oil [3/]. In or r to check foe temperature of the melt in foe scattering volume a number of techniques were tested, an optical pyrometer indicated ttot the data taken close to the x-ray position (in figure 3a) had a temperature in excess of 120 °C. l ilst it is undoubtedty true that at lor% times crystallization proceeds from the exterior of the tape, is unlikety that it has occurred in foe data preser here. 

Lumiaho, J., Heino, A., Kauppinen, T., et al. Drainage and antireflux characteristics of a biodegradable self-reinforced, self-expanding X-ray-positive poly-L, D-lactide spiral partial ureteral stent an experimental study. J. Endourol. Endourol. Soc. 21, 1559-1564 (2007). doi 10.1089/end.2005.0085... 

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