Understanding the liquid structure provides information that is crucial to uncovering the nature of the glass-liquid transition. We apply an aerodynamic levitation technique and high-energy X-rays to liquid (l)-Er 2 O 3 to discover its structure. The sample densities are measured by electrostatic levitation at the International Space Station. Liquid Er 2 O 3 displays a very sharp diffraction peak (principal peak). Applying a combined reverse Monte Carlomolecular dynamics approach, the simulations produce an Er-O coordination number of 6.1, which is comparable to that of another nonglass-forming liquid, l-ZrO 2. The atomic structure of l-Er 2 O 3 comprises distorted OEr 4 tetraclusters in nearly linear arrangements, as manifested by a prominent peak observed at~180°in the Er-O-Er bond angle distribution. This structural feature gives rise to long periodicity corresponding to the sharp principal peak in the X-ray diffraction data. A persistent homology analysis suggests that l-Er 2 O 3 is homologically similar to the crystalline phase. Moreover, electronic structure calculations show that l-Er 2 O 3 has a modest band gap of 0.6 eV that is significantly reduced from the crystalline phase due to the tetracluster distortions. The estimated viscosity is very low above the melting point for l-ZrO 2 , and the material can be described as an extremely fragile liquid.

Acrylate 4, prepared from diacetylrhamnal, underwent intramolecular Diels-Alder cycloaddition to give the thermodynamically disfavored trans-fused gamma-lactone 15 as the major product, along with two stereoisomeric cycloadducts. A computational analysis of each of the four transition states arising from 4 and the corresponding cycloadducts permits an understanding of the contrasting requirements for kinetic versus thermodynamic control of the reaction.

1. Cross-correlation analysis was made in the taste-sensitive neuron pairs recorded simultaneously from the parabrachial nucleus (PBN) of rats. Three indexes were adopted to evaluate the activities of the taste neurons; namely, 1) spike response density (RD value), which is the net spike density to stimulation with the four basic tastes; 2) the frequency of correlated discharges (FC value in spikes per second), which was determined by measuring the area of the peak appearing in the cross-correlogram (CC) during application of the test fluids; and 3) the weight of correlated discharge (WC = FC/RD), which shows the relative importance of correlated discharges in the taste signals delivered by a component neuron of a given pair. 2. In 11 of 23 pairs, the CCs exhibited peaks during stimulation with tastants. These 11 pairs, which were recorded in the pontine taste area, were composed of 18 NaCl-best (most sensitive to NaCl) and 4 HCl-best neurons. In eight pairs, the best-stimulus of both of the component neurons was NaCl, and it was HCl in one pair (homo-type pairs). The remaining two pairs were composed of an NaCl-best and an HCl-best neuron (hetero-type pairs). 3. In eight homo-type pairs (7 NaCl-best pairs and 1 HCl-best pair), each pair exhibited the maximal FC value during stimulation with the best-stimulus of the component neurons (2.3 less than or equal to maximal FC less than or equal to 26.6 Hz). In the remaining three pairs, the maximal FC values were low (0.8-1.9 Hz).(ABSTRACT TRUNCATED AT 250 WORDS)

This study examines the nature of the efferent projection of omnipause neurons (OPNs) in the midline pontine tegmentum to medium-lead burst neurons (BNs) in the Forel's field H (FFH), both of which exhibit activities related to vertical eye movements, using chronically prepared alert cats. Antidromic spikes of the BNs evoked by oculomotor nucleus stimulation were suppressed by shortly preceding (less than 5 ms) microstimulation within the OPN area including actual recording sites of OPNs. Many OPNs were antidromically activated by microstimulation at recording sites of the BNs. Furthermore, systematic tracking in and around the FFH with the stimulating microelectrode substantiated that the OPNs issued axonal branches within the BN area. These results suggest direct inhibitory projection of OPNs to the BNs.