Methionine bound to Pd/γ-Al2O3 catalysts studied by solid-state (13)C NMR

Dynamic observations of various oligomers in amyloid β isoforms using laboratory diffracted X-ray blinking

Acceleration of societal ageing has increased the global incidence of geriatric diseases such as Alzheimer's disease (AD), and the demands for proper diagnosis and monitoring of those diseases are also increasing daily. We utilized diffracted X-ray blinking (DXB) for amyloid β (Aβ) isoforms, which are thought to be closely related to AD, to discriminate among the dynamics of individual particles in early and long-term oligomerisation and aggregation inhibiting environments. Among the various Aβ isoforms, the dynamics of Aβ (1–42), which is known to be the most toxic form, were the slowest (the dynamics were lower by 78% com-pared with short-term incubation), and the dynamics were restored (the dynamics increased by 105% compared with normal aggregation) in an environment that suppressed oligomerisation of Aβ (1–42). It has been confirmed that the use of DXB allows measurements of dynamics related to the functional states of the target molecules.

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The Dynamics of Amyloid β in early oligomerisation was measured by Diffracted X-ray Blinking, pico-meter scale method.

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The dynamics of Amyloid β was shrinked in more oligomerisation.

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The dynamics of Amyloid β (1–42) on Pd surface were recovered by 105% compared with that of normal oligomerisation.

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Dynamical measurement captured the recovery of Amyloid β (1–42); it is important to measure the dynamics of the oligomer.

Protective Carbon Overlayers from 2,3-Naphthalenediol Pyrolysis on Mesoporous SiO₂ and Al₂O₃ Analyzed by Solid-State NMR

Hydrothermally stable carbon overlayers can protect mesoporous oxides (SiO₂ and Al₂O₃) from hydrolysis during aqueous-phase catalysis. Overlayers made at 800 °C by pyrolysis of 2,3-naphthalenediol deposited out of acetone solution were analyzed by solid-state ¹³C nuclear magnetic resonance (NMR) spectroscopy. Power absorption due to sample conductivity was prevented by diluting the sample in nonconductive and background-free tricalcium phosphate. While pyrolysis on SiO₂ produced a predominantly aromatic carbon film, at least 15% of nonaromatic carbon (sp³-hybridized C as well as C=O) was observed on γ-Al₂O₃. These species were not derived from residual solvent, according to spectra of the same material treated at 400 °C. The sp³-hybridized C exhibited weak couplings to hydrogen, short spin-lattice relaxation times, and unusually large shift anisotropies, which are characteristics of tetrahedral carbon with high concentrations of unpaired electrons. Moderate heat treatment at 400 °C on SiO₂ and Al₂O₃ resulted in yellow-brown and nearly black samples, respectively, but the darker color on Al₂O₃ did not correspond to more extensive carbonization. Aromatic carbon bonded to hydrogen remained predominant and the peaks of naphthalenediol were still recognizable; however, some of the chemical shifts differed by up to 5 ppm, indicating significant differences in local structure. On SiO₂, additional sharp peaks were detected and attributed to 1/3 of the 2,3-naphthalene molecules undergoing fast, nearly isotropic motions.

Identifying low-coverage surface species on supported noble metal nanoparticle catalysts by DNP-NMR

DNP-NMR spectroscopy has been applied to enhance the signal for organic molecules adsorbed on γ-Al₂O₃-supported Pd nanoparticle catalysts.