No abstract

The trace element content of the brain of two patients with Pick's disease examined postmortem was studied using instrumental neutron activation analysis. Results showed significant increases in chlorine, iron, manganese, sodium, and phosphorus and significant decreases in chromium, cesium, rubidium, and selenium and in the mean freeze-dried to wet-weight ratio for patients with Pick's disease compared with control patients. Brain zinc content was not elevated in the two patients, a finding that fails to support the hypothesis that elevated zinc levels play a role in the pathogenesis of Pick's disease.

Instrumental neutron activation analysis procedures were used to determine the aluminum content of various brain regions in histologically verified Alzheimer disease (AD) and in controls. The grand mean aluminum level for 74 AD specimens was 0.372 +/- 0.058 microgram/gm and for 137 adult controls, 0.467 +/- 0.033 microgram/gm, both on a wet weight basis. No difference was found at the bulk sample level between AD and adult controls, corrected for age and sex, or when frontal, temporal, and hippocampal specimens were compared. Control specimens (infancy to 85 years) showed an increase in brain aluminum concentration with age. Comparison of freeze-dried to wet weight ratios of AD and controls revealed a small increase in water content in AD brains.

Thiol containing molecules as both interfacial surface ligands and additives are promising modulators for enhancing photoluminescence (PL) properties, stability, and photovoltaic (PV) performance of metal halide perovskites. However, alkanethiols are much more effective for improving photoluminescence (PL) intensity and stability in metal halide perovskite nanocrystals than in their thin film analogues. Herein, we investigate how additional functional groups on a pyrimidine core can alter thiol reactivity and influence the PL, stability, and PV performance of organic metal halide perovskites. Through an investigation of five different pyrimidine derivatives, it is shown that all derivatives containing thiol groups form thiolates in the presence of the perovskite precursors and increase the photoluminescence intensity of the perovskite film. The largest all-around improvement to the PL intensity, stability, and photovoltaic performance of Cs 0.15 FA 0.85 PbI 3 perovskites is realized through the addition of a hydroxyl group combined with a trifluoromethyl group to form 4-hydroxy-6-(trifluoromethyl)pyrimidine-2-thiol. This investigation helps illuminate how combinations of functional groups can be employed to further increase the beneficial effects over monofunctional additives in organic metal halide perovskites.

N, N′-bis (isatin) diamine schiff base ligands were synthesized by the condensation reaction of Isatin with various diamine (ethane-1,2-diamine, propane-1,3-diamine and hexane-1,6-diamine) in 2:1 molar ratios. These ligands were used to prepare Zr (IV) complexes. Prepared ligands and complexes were characterized by using conductance measurement, FT-IR, UV-Visible and 1 HNMR spectroscopy. The presence of FT-IR band for azomethine group supports the formation of ligand. Vibrational bands for Zr←N and Zr←O in complexes signify the coordination through O and N sites of ligands. 1 HNMR peak for NH moiety in ligand gets almost disappeared in complex reveals tautomerism of NH with nearby carbonyl oxygen due to the effect of complexation. The absence of peak above 500 nm in the electronic spectra indicates d 0 system of zirconium in complexes. The elemental analytical data was analogous to theoretical composition of ligands and complexes. The molar conductance values obtained for the complexes represent their non-electrolytic character.