Avance 3 hd console

PRE data were measured with magic angle spinning using a 14.09T Bruker Ascend magnet with Avance III HD console and equipped with a 3.2 mm E^Free probe (Bruker, Billerica, USA). Dipolar assisted rotational resonance (DARR) experiments53 (link) were performed at a MAS rate of 10.0 kHz at −19 °C and 4 °C (the latter for control experiments only), using a 1 ms contact time and 20 ms mixing time in ¹³C-¹³C cross polarization experiments. PRE data were measured by using unlabelled membranes to measure a reference spectrum and then obtaining spectra by using paramagnetic labeled membranes doped with 2% 1-palmitoyl-2-stearoyl-[5-doxyl]-sn-glycero-3-phosphocholine or 2% 1-palmitoyl-2-stearoyl-[10-doxyl]-sn-glycero-3-phosphocholine (Avanti Polar Inc., Alabaster, USA), which carry an unpaired electron in their doxyl group positioned at the level of the 5^th and 10^th carbon atom of the lipid chain, respectively (Fig. 4b,c).

The study was performed using 6- to 8-month-old C57BL/6 J (wild-type (WT), n = 5) mice and APP^NL-F knock-in (AD, n = 5) mice using a protocol approved by the IAUCAC committee of the University of Pennsylvania. Prior to the MRI experiments, the mouse was anesthetized using 1.5% isoflurane and its head was placed in a conical head restrainer. A respiratory pillow pad and rectal probe were used to monitor the breathing rate and body temperature, respectively, of the mouse throughout the MRI experiments. The conical restrainer was placed in a 20 mm diameter ¹H transceiver volume head coil (m2m Imaging) and MRI experiments were performed on a 9.4 T horizontal magnet interfaced with an Avance III HD console (Bruker BioSpin, Germany).

The level of deuteration of the cholesterol was determined by ¹H-NMR, measured at the Institut de Biologie Structurale (IBS), Grenoble, France. The samples were measured at a 4 mM concentration in deuterated chloroform. No internal standard was used. However, the non-deuterated cholesterol sample was set as a reference for 0% deuteration. The instrument used was a 600 MHz Bruker NMR spectrometer with an avance III HD console. A spectral width of 25 ppm was obtained, 32 scans were carried out with a relaxation delay of 20 sec and an acquisition time of 0.5 sec per scan. Bruker TopSpin software was used to analyse the data.

NMR data were acquired on an Oxford 800 MHz magnet equipped with an Avance III HD console and 3 mm TCI cryoprobe (Bruker BioSpin). Samples were kept at 6 °C in the SampleJet before measurement at 25 °C. One-dimensional excitation sculpting with perfect echo pulse sequence (‘zgespe’) was used to acquire profiling data. With a sweep width of 20 ppm, 128 scans were acquired in 64 k points, using an acquisition time of 2.04 s and relaxation delay of 3 s. Data were zero-filled to 128 k and Fourier-transformed including 0.3 Hz exponential line-broadening. Spectra were phased and referenced to the TSP-d4 signal. All processing was performed in TopSpin 3.5 pl6 (Bruker BioSpin).

Infant blood samples were collected at postnatal days (PND) 1, 7, 14, and 28, and at postmenstrual age (PMA) 32, 36, and 40 weeks. The blood was allowed to clot at 4°C for a minimum of 45 min and a maximum of 2 h before centrifugation at room temperature at 1500 g for 10 min. The serum was then transferred into cryovials and stored at −20°C for up to 1 week before long-term storage at −80°C until analysis. All samples had been subjected to at least one, but less than five, freeze-thaw cycle before NMR analysis.
Serum samples (50 μl) were prepared and then analyzed on an Oxford 800 MHz magnet equipped with an Avance III HD console and 3 mm TCI cryoprobe (Bruker BioSpin). Details of sample processing and the ¹H NMR analysis have been published (Nilsson et al., 2020 (link)). Tentative annotations of peaks were made using ChenomX 8.3 (ChenomX Inc.) and the spectral data in the Human Metabolome Data Bank (Wishart et al., 2018 (link)). In total, 260 NMR features were detected in the serum samples. From these, 31 metabolites could be chemically and structurally annotated. In instances where multiple features represented a single metabolite, a strong well-separated peak was selected, or two or more peaks were summarized. All metabolite levels are reported as normalized NMR signals or as standardized values.