Delta nmr processing and control software

²⁹Si MAS NMR spectra were collected at 99.4 MHz on JEOL ECA-500 (magnetic field 11.75T, Tokyo, Japan) using a 3.2 mm φ probe. The ²⁹Si NMR experiments employed a spinning speed at 10 kHz, a pulse width of 3.6 μs, a relaxation delay of 15 s and total 2500 scans. Analysis of the solid-state NMR spectra was performed on a JEOL Delta NMR processing and control software.

Methods for ¹H-NMR measurement and FID analysis using STFT are described elsewhere^{28 (link)}. Briefly, each serum sample (200 μL) was mixed with 400 μL of deuterium oxide (²H₂O) (ISOTEC, Sigma-Aldrich, St. Louis, MO, USA) and pipetted into a 5-mm (outer diameter) NMR tube (Wilmad-LabGlass, Vineland, NJ, USA) for NMR analysis. Solution-state NMR analyses were performed at a proton resonance frequency of 300 MHz (7.05 T) using an ECX NMR spectrometer (JEOL, Tokyo, Japan) interfaced with a TH5 probe (auto-tunable type) equipped with Delta NMR processing and control software (version 4.3.2; JEOL). FIDs were acquired using a single pulse with a 2.0-s relaxation delay between repeated pulse sequences and subsequently processed using LabVIEW 2015 software (version 15.0.1f1; National Instruments Corp., Austin, TX, USA). STFT was performed using the FID data and spectrograms were generated as a visual representation of the time–frequency analysis. Each spectrogram datum in the two-dimensional matrix was read from left to right and row by row and populated in a single row. In this study, each spectrogram datum was reshaped from a 257 × 512 two-dimensional matrix into a 1 × 131,584 single row. After combining the total rows into a separate 66 × 131,584 matrix, the resulting dataset was used to perform multivariate data analysis.

Each serum sample (100 μL) was mixed with 500 μL of deuterium oxide (²H₂O) (ISOTEC, Sigma-Aldrich, St. Louis, MO, USA) and pipetted into a 5-mm (outer diameter) NMR tube (Wilmad-LabGlass, Vineland, NJ, USA) for NMR analysis [23 (link)]. Solution-state NMR analyses were performed at a proton resonance frequency of 400 MHz (9.4 Tesla) using an ECZ^™ NMR spectrometer (JEOL Ltd., Tokyo, Japan) interfaced with a probe (digital auto-tunable type [NM-03812RO5S]) and equipped with Delta^™ NMR processing and control software, version 5.3.2 (JEOL Ltd.). The field was locked to the ²H resonance of the ²H₂O solvent. One-dimensional proton NMR signals were automatically acquired at a probe temperature of 30°C using the program supplied by JEOL that supported the macro function in Delta^™. Free induction decay (FID) data were acquired using a single pulse with a 2.0-s relaxation delay between repeated pulse sequences. The strong signal arising from free water was suppressed using DANTE presaturation. Other conditions were as follows: radio-frequency pulse width, 2.93 μs; acquisition time, 1.636 s; repetition time, 3.636 s; spectral width, 10,016 Hz; number of data points, 16,384; and number of steady-state transients, 400. The FID data were saved in JEOL Delta format (JDF).