Validity of the NIH toolbox cognitive battery in a healthy oldest-old 85+ sample.

OBJECTIVE: To evaluate the construct validity of the NIH Toolbox Cognitive Battery (NIH TB-CB) in the healthy oldest-old (85+ years old). METHOD: Our sample from the McKnight Brain Aging Registry consists of 179 individuals, 85 to 99 years of age, screened for memory, neurological, and psychiatric disorders. Using previous research methods on a sample of 85 + y/o adults, we conducted confirmatory factor analyses on models of NIH TB-CB and same domain standard neuropsychological measures. We hypothesized the five-factor model (Reading, Vocabulary, Memory, Working Memory, and Executive/Speed) would have the best fit, consistent with younger populations. We assessed confirmatory and discriminant validity. We also evaluated demographic and computer use predictors of NIH TB-CB composite scores. RESULTS: Findings suggest the six-factor model (Vocabulary, Reading, Memory, Working Memory, Executive, and Speed) had a better fit than alternative models. NIH TB-CB tests had good convergent and discriminant validity, though tests in the executive functioning domain had high inter-correlations with other cognitive domains. Computer use was strongly associated with higher NIH TB-CB overall and fluid cognition composite scores. CONCLUSION: The NIH TB-CB is a valid assessment for the oldest-old samples, with relatively weak validity in the domain of executive functioning. Computer use's impact on composite scores could be due to the executive demands of learning to use a tablet. Strong relationships of executive function with other cognitive domains could be due to cognitive dedifferentiation. Overall, the NIH TB-CB could be useful for testing cognition in the oldest-old and the impact of aging on cognition in older populations.

Ag(I) induced emission with azines having donor-acceptor-donor chromophore.

Two azine molecules, [3-{4-(dimethylamino)phenyl}prop-2-en-1-ylidene]hydrazone (HL) and [4-(dimethylamino)benzylidene]hydrazone (LL) synthesized via Schiff base condensation, show an absorption band due to intra-ligand charge transfer (ILCT). Both ligands show weak emission in the absence of a metal ion as input. When Ag(+) ions are added to either compound in THF, the metal ion gets bonded to the azine moiety resulting in a high intensity emission (approximately 400 fold). While Cu(+) shows a slight enhancement of emission, other first-row transition, alkali or alkaline-earth metal ions do not show any emission allowing Ag(+) ions to be detected in the presence of these metal ions. Both the Ag(+) complexes were characterised by X-ray crystallography and show solid-state spectra similar to their solution spectra. Time-resolved fluorescence measurements done on the complexes show two excited-state lifetimes.

A coumarin-derived fluorescence probe selective for magnesium.

Two different coumarin derivatives have been connected via an imine linkage to obtain a new fluorescence signaling system. This compound itself does not show any emission due to rapid isomerization around the C[double bond]N bond. However, in the presence of a Mg(II) ion, this isomerization is stopped because of bonding to the metal ion resulting in high-intensity (approximately 550-fold) emission. Other metal ions like Li(I), Ca(II), and Zn(II) show very little emission, while biologically relevant transition-metal ions do not show any emission. In this way, the Mg(II) ion can be detected in the presence of these ions.

Structure of 1% copper(II)-doped dichlorobis(1,2-dimethylimidazole)zinc(II).

[Zn0.99Cu0.01Cl2(C5H8N2)2], Mr = 328.43, monoclinic, P2(1)/c, a = 13.587 (1), b = 7.1324 (7), c = 16.356 (2) A, beta = 112.87 (1) degrees, V = 1460.4 (5) A3, Z = 4, Dm = 1.50 (1), Dx = 1.492 g cm-3, mu(Mo K alpha, lambda = 0.71073 A) = 20.8 cm-1, F(000) = 672.0, T = 297 (1) K, R = 0.028 for 1782 unique observed reflections. The structure contains discrete dichlorobis(1,2-dimethylimidazole)zinc(II) molecules. Pseudotetrahedral N2Cl2 coordination about zinc is effected by coordination to two imidazole and two chloride ligands. The Zn-N [2.006 (3), 2.008 (3) A] and Zn-Cl [2.2509 (8), 2.2468 (8) A] distances lie within +/- 0.01 A of those in the structurally similar compound [ZnCl2(imidazole)2]. Angles within the coordination sphere L-Zn-L' range from 105.39 (7) to 115.37 (8) degrees. The N-Zn-N angle [115.37 (8) degrees] is 5-10 degrees larger than those for several [ZnL2Cl2] complexes where L is imidazole, 4-substituted pyridine or 3,5-dimethylpyrazole.

Structure of a novel, macrocyclic Schiff base.

(E,E)-1,2,3,4,4a alpha, 12a beta-Hexahydro-7,7,10,- 10-tetramethyl-7H,10H-8,9-dithia-5,12-diazabenzo-cyclodec ene, C14H24N2S2, Mr = 284.49, monoclinic, P2(1)/n, a = 8.962 (1), b = 19.356 (3), c = 10.178 (1) A, beta = 114.49 (1) degrees, V = 1606.7 (7) A3, Z = 4, Dm = 1.21 (1), D chi = 1.176 Mg m-3, mu (Mo K alpha, lambda = 0.71073 A) = 0.31 mm-1, F(000) = 616, T = 296 (1) K, RF = 0.031 for 2066 reflections. The molecule has approximate point symmetry 2 and consists of a 1,2-trans-disubstituted cyclohexane (chair conformation) fused to a ten-membered ring that contains one disulfide and two, trans-substituted, imino groups. Structural parameters associated with the disulfide group, including the C-S-S-C torsion angle [90.8 (1) degrees], are similar to those reported for several acyclic disulfides. The N-C-C-N torsion angle [-63.1 (2) degrees] associated with disubstitution of the cyclohexane ring is substantially larger than those found for protonated or chelated 1,2-trans-diamino-cyclohexane.