X-ray Photoelectron Spectroscopy of Pyridinium-Based Ionic Liquids: Comparison to Imidazolium- and Pyrrolidinium-Based Analogues.

We investigate eight 1-alkylpyridinium-based ionic liquids of the form [Cn Py][A] by using X-ray photoelectron spectroscopy (XPS). The electronic environment of each element of the ionic liquids is analyzed. In particular, a reliable fitting model is developed for the C 1s region that applies to each of the ionic liquids. This model allows the accurate charge correction of binding energies and the determination of reliable and reproducible binding energies for each ionic liquid. Shake-up/off phenomena are determinedfor both C 1s and N 1s spectra. The electronic interaction between cations and anions is investigated for both simple ionic liquids and an example of an ionic-liquid mixture; the effect of the anion on the electronic environment of the cation is also explored. Throughout the study, a detailed comparison is made between [C8 Py][A] and analogues including 1-octyl-1-methylpyrrolidinium- ([C8 C1 Pyrr][A]), and 1-octyl-3-methylimidazolium- ([C8 C1 Im][A]) based samples, where X is common to all ionic liquids.

Operant elevation of blood pressure in unrestrained olive baboons (Papio cynocephalus anubis).

This report describes an operant conditioning method for producing increases in the blood pressure and heart rate of baboons in which (A) chair restraint is completely eliminated by a tether system for continuous direct monitoring of arterial pressure, and (B) electric shock is replaced by blasts of compressed air. In our computer-automated procedure, the home-caged subject receives a banana-flavored reward pellet each time it accumulates 120 s during which its diastolic pressure is above a prespecified criterion. Conversely, the animal receives a blast of compressed air each time it accumulates 120 s during which its diastolic pressure is below criterion. After 20-70 8-h sessions of conditioning, 44%, 28%, 24%, 22%, and 17% elevations over baseline diastolic pressures were observed in five baboons. Systolic pressures also increased from 5% to 28%, and heart rate increased from 7% to 51%. The conditioning procedure was associated with an attenuation of the normal afternoon decline in plasma cortisol levels. These results demonstrate that compressed-air blasting can be used as an alternative to electric shock for operant conditioning of autonomically mediated responses in nonhumn primates. This model may be useful for the study of hypertension, atherosclerosis, and related cardiovascular diseases.