East of sunrise

An anthology of short fiction by Curtis Scott Shumaker

A Series of Isopropyl-Substituted Oligogermanes Pr^<i>i</i>₃Ge(GePh₂)_<i>n</i>GePr^<i>i</i>₃ (<i>n</i> = 0–3) Featuring a Luminescent and Dichroic Pentagermane Pr^<i>i</i>₃Ge(GePh₂)₃GePr^<i>i</i>₃

The series of oligogermanes Pr^<i>i</i>₃Ge­(GePh₂)_<i>n</i>GePr^<i>i</i>₃ (<i>n</i> = 0, <b>2</b>; <i>n</i> = 1, <b>3</b>; <i>n</i> = 2, <b>4</b>; <i>n</i> = 3, <b>5</b>) were prepared by the hydrogermolysis reaction. All four species were characterized by NMR (¹H and ¹³C) and UV/visible spectroscopy as well by cyclic voltammetry and differential pulse voltammetry. The oligogermanes exhibited a successive red shift in their absorbance maxima as the length of the Ge–Ge chain was increased, and these molecules also became easier to oxidize as the chain length was increased. The X-ray crystal structures of <b>4</b> and <b>5</b> as well as the trigermane HPh₂GeGePh₂GePh₂H (<b>6</b>) were determined. The pentagermane <b>5</b> was shown to be dichroic in the solid state due to the packing of the individual molecules in a columnar fashion in the crystal. Pentagermane <b>5</b> is also luminescent in solution, exhibiting an emission maximum at 380 nm. The physical properties of <b>5</b>, like the hexagermane Pr^<i>i</i>₃Ge­(GePh)₄GePr^<i>i</i>₃, mimic the properties of the larger polygermane systems

Differential Effects of Dopamine Receptor D1-Type and D2-Type Antagonists and Phase of the Estrous Cycle on Social Learning of Food Preferences, Feeding, and Social Interactions in Mice

The neurobiological bases of social learning, by which an animal can ‘exploit the expertise of others' and avoid the disadvantages of individual learning, are only partially understood. We examined the involvement of the dopaminergic system in social learning by administering a dopamine D1-type receptor antagonist, SCH23390 (0.01, 0.05, and 0.1 mg/kg), or a D2-type receptor antagonist, raclopride (0.1, 0.3, and 0.6 mg/kg), to adult female mice prior to socially learning a food preference. We found that while SCH23390 dose-dependently inhibited social learning without affecting feeding behavior or the ability of mice to discriminate between differently flavored diets, raclopride had the opposite effects, inhibiting feeding but leaving social learning unaffected. We showed that food odor, alone or in a social context, was insufficient to induce a food preference, proving the specifically social nature of this paradigm. The estrous cycle also affected social learning, with mice in proestrus expressing the socially acquired food preference longer than estrous and diestrous mice. This suggests gonadal hormone involvement, which is consistent with known estrogenic regulation of female social behavior and estrogen receptor involvement in social learning. Furthermore, a detailed ethological analysis of the social interactions during which social learning occurs showed raclopride- and estrous phase-induced changes in agonistic behavior, which were not directly related to effects on social learning. Overall, these results suggest a differential involvement of the D1-type and D2-type receptors in the regulation of social learning, feeding, and agonistic behaviors that are likely mediated by different underlying states