Warren Warren

A recent paper in this journal presents magnetic resonance imaging (MRI) data on humans which are asserted to ‘suggest that we may have witnessed entanglement mediated by consciousness-related brain functions. Those brain functions must then operate non-classically, which would mean that consciousness is non-classical.’ Unfortunately, the article provides no evidence to justify this claim. In fact, the paper only provides evidence for what we already knew: the brain (and any other living tissue) is complex, multicompartmental, and imprecisely characterized by MRI.

Hyperpolarized [1-¹³C]pyruvate is a revolutionary molecular probe enabling ultrafast metabolic MRI scans in 1 min. This technology is now under evaluation in over 30 clinical trials, which employ dissolution Dynamic Nuclear Polarization (d-DNP) to prepare a batch of the contrast agent; however, d-DNP technology is slow and expensive. The emerging SABRE-SHEATH hyperpolarization technique enables fast (under 1 min) and robust production of hyperpolarized [1-¹³C]pyruvate via simultaneous chemical exchange of parahydrogen and pyruvate on IrIMes hexacoordinate complexes. Here, we study the application of microtesla pulses to investigate their effect on C-13 polarization efficiency, compared to that of conventional SABRE-SHEATH employing a static field (∼0.4 μT), to provide the matching conditions of polarization transfer from parahydrogen-derived hydrides to the ¹³C-1 nucleus. Our results demonstrate that using square-microtesla pulses with optimized parameters can produce ¹³C-1 polarization levels of up to 14.8% (when detected, averaging over all resonances), corresponding to signal enhancement by over 122,000-fold at the clinically relevant field of 1.4 T. We anticipate that our results can be directly translated to other structurally similar biomolecules such as [1-¹³C]α-ketoglutarate and [1-¹³C]α-ketoisocaproate. Moreover, other more advanced pulse shapes can potentially further boost heteronuclear polarization attainable via pulsed SABRE-SHEATH.

Pulse spectral-domain differential-phase-shift-keying has been demonstrated using AOM-based pulse shaping for modulation and spectral interferometry for demodulation. The encoded differential phase is successfully retrieved despite of the nonlinear distortions after 4-km dispersion-shifted fiber transmission.

Femtosecond laser pulse shaping and novel pulse shape detection methods can be used to develop Tb/s communications architectures, measure the onset of fiber nonlinearity, correct for distortions in optical amplifiers, and improve characterization of surfaces.