Purpose: To develop a high temporal resolution imaging method that measures muscle-specific phosphocreatine (PCr) resynthesis time constant (τ ) and pH changes in muscles of the lower leg following exercise on a clinical 3T MRI scanner.
Methods: We developed a frequency-selective 3D non-Cartesian FLORET sequence to measure PCr with 17-mm nominal isotropic resolution (28 mm actual resolution) and 6-s temporal resolution to capture dynamic metabolic muscle activity. The sequence was designed to additionally collect inorganic phosphate spectra for pH quantification, which were localized using sensitivity profiles of individual coil elements. Nineteen healthy volunteers were scanned while performing a plantar flexion exercise on an in-house developed ergometer. Data were acquired with a dual-tuned multichannel coil array that enabled phosphorus imaging and proton localization for muscle segmentation.
Results: After a 90-s plantar flexion exercise at 0.66 Hz with resistance set to 40% of the maximum voluntary contraction, τ was estimated at 22.9 ± 8.8 s (mean ± standard deviation) with statistical coefficient of determination r = 0.89 ± 0.05. The corresponding pH values after exercise were in the range of 6.9-7.1 in the gastrocnemius muscle.
Temperate mixed forests are currently experiencing severe drought conditions and face increased risk of degradation. However, it remains unclear how critical tree physiological functions such as sap flow density (SFD) and tree water deficit (TWD, defined as reversible stem shrinkage when water is depleted), respond to extreme environmental conditions and how they interact under dry conditions. We monitored SFD and TWD of three co-occurring European tree species (Fagus sylvatica, Fraxinus excelsior and Acer pseudoplatanus) in dry conditions, using high temporal resolution sap flow, dendrometer, and environmental measurements.
Background: For the development and validation of dynamic treatment modalities and processes on the MR-linac, independent measurements should be performed that validate dose delivery and linac behavior at a high temporal resolution. To achieve this, a detector with both high temporal and spatial resolution is necessary.
Purpose: This study investigates the suitability of a Delta4 Phantom+ MR (Delta4) detector array for time-resolved dosimetry in the 1.
Non-invasive brain-computer interfaces (BCI) hold great promise in the field of neurorehabilitation. They are easy to use and do not require surgery, particularly in the area of motor imagery electroencephalography (EEG). However, motor imagery EEG signals often have a low signal-to-noise ratio and limited spatial and temporal resolution.
We demonstrate a new, to the best of our knowledge, range-scalable repeatered distributed acoustic sensing (DAS) solution sharing technology with existing long-haul subsea telecom networks capable of low noise and high spatial and temporal resolution. Single ended DAS interrogation through a 2227 km line comprising 39 repeatered fiber spans is demonstrated with a 10 m spatial resolution, a 1.78 kHz sampling rate, and a strain resolution of 35 pε/√Hz for the outermost span.
Biomolecular sensors with single-molecule resolution are composed of multitudes of transducers that measure state changes related to single-molecular binding and unbinding events. Conventionally, signals are aggregated from many individual transducers in order to achieve sufficient statistics. However, by aggregating signals, transducer-to-transducer differences are lost and heterogeneities cannot be studied.
