ABSTRACT
Objective To determine if there is atrophy of neuronal nuclei in the aging rat hippocampus.Methods The entire hippocampal formation in a cerebral hemisphere (on a random side) was removed from normal male SD rats aged 1, 2 and 3 years (each age-group 5 rats), serial sections (section thickness 40 |xm) were cut after embedding in a resin of glycol methacrylate, and 3-4 sections were systematically sampled and stained with periodic acid, Schiff' s reagent and hematoxylin. The nuclear sizes of hippocampal neurons were estimated with stereological methods, first, the nuclei were sampled in a uniform random way using the optical disector; then, a Feret diameter of the largest nuclear profile at its focal plane (optical section) was measured as the nuclear diameter, and the nuclear volume was measured at the clearest focal plane of the nucleolus with the nucleator. Results The mean diameters and volumes of the neuronal nuclei in the whole hippocampus were 8.7-9.2 |xm and 392-457 (Jim, respectively, in the 3 age-groups, without significant statistical difference between groups. There were no significant difference between groups, either, in the nuclear diameter or volume in each hippocampal region——the GA (hippocampus proper), dentate gyrus or subiculum. Conclusion In general, no age-related changes have been observed in the nuclear sizes of neurons in the whole hippocampus in the rat from middle to old age.
ABSTRACT
Four magnetic samples with different building blocks and dimensionalities, {[Cu(4)(atr)(2)(µ(3)-OH)(2)(sip)(2)]·4H(2)O}(n) (1), {[Cu(4)(atr)(2)(H(2)O)(8)(µ-OH)(2)(sip)(2)]·1.3CH(3)OH·0.7H(2)O}(n) (2), {[Cu(3)(atr)(4)(H(2)O)(2)(sip)(2)]·4H(2)O}(n) (3) and {[Cu(3)(atr)(4)(H(2)O)(2)(µ(3)-OH)(sip)(Hsip)]·2CH(3)OH·2.75H(2)O}(n) (4) (atr = 4-amino-1,2,4-triazole and sip(3-) = 5-sulfoisophthalate), were obtained and characterized structurally and magnetically. Complex 1 exhibits a three-dimensional (3D) robust framework with butterfly-like Cu(II)(4) clusters periodically extended by tetratopic sip(3-) connectors. Complex 2 possesses a 2D layer with alternating Cu(II)(3) + Cu(II)(1) chains crosslinked by pairs of ditopic sip(3-) linkers. By contrast, the latter two entities feature 1D broad ribbons with linear (for 3) and triangular Cu(II)(3) cores (for 4) propagated by bidirectional sip(3-) connectors. Structural analysis reveals that the diverse building blocks and dimensionalities of 1-4 are significantly dominated by the tunable coordination of exocyclic amino- and/or sulfonate-group of the mixed ligands. Magnetically, antiferromagnetic interactions with variable strength transmitted by -NN- moiety of atr and hydroxyl mediators result in overall S = 0 (for 1) and 1/2 (for 3 and 4) spin ground states. These interesting results indicate that coordinative side group in the ternary metal ion-azolate-carboxylate system can be utilized to generate aesthetically pleasing building units and variably polytopic connectors, leading to differently extended superstructures and magnetic behavior.
ABSTRACT
Cocrystallization of benzimidazole with benzene 1,3,5-tricarb-oxy-lic acid in slightly basic medium afforded the title compound, C(7)H(7)N(2) (+)·C(9)H(5)O(6) (-)·3H(2)O, in which one of the imidazole N atom is protonated and one carb-oxy-lic group of aromatic acid is deprotonated. In the crystal structure, inter-molecular N-Hâ¯O hydrogen-bonding connects the two organic components into dimers, which are further linked into a three-dimensional network by O-Hâ¯O and N-Hâ¯O inter-actions between the water mol-ecules and the dimers.
