The Quantum Twisting Microscope

The invention of scanning probe microscopy has revolutionized the way electronic phenomena are visualized. While present-day probes can access a variety of electronic properties at a single location in space, a scanning microscope that can directly probe the quantum mechanical existence of an electron at multiple locations would provide direct access to key quantum properties of electronic systems, so far unreachable. Here, we demonstrate a conceptually new type of scanning probe microscope - the Quantum Twisting Microscope (QTM) - capable of performing local interference experiments at its tip. The QTM is based on a unique van-der-Waals tip, allowing the creation of pristine 2D junctions, which provide a multitude of coherently-interfering paths for an electron to tunnel into a sample. With the addition of a continuously scanned twist angle between the tip and sample, this microscope probes electrons in momentum space similar to the way a scanning tunneling microscope probes electrons in real space. Through a series of experiments, we demonstrate room temperature quantum coherence at the tip, study the twist angle evolution of twisted bilayer graphene, directly image the energy bands of monolayer and twisted bilayer graphene, and finally, apply large local pressures while visualizing the evolution of the flat energy bands of the latter. The QTM opens the way for novel classes of experiments on quantum materials

Remote electrical neuromodulation (REN) wearable device for adolescents with migraine: a real-world study of high-frequency abortive treatment suggests preventive effects

IntroductionMigraine is a chronic neurological disease manifesting as attacks of disabling head pain and associated symptoms. Remote electrical neuromodulation (REN) is a non-pharmacological, prescribed, wearable device (Nerivio®). This device has been certified by the FDA for the acute and/or preventive treatment of migraine with or without aura in patients 12 years of age or older. The device is affixed to the user’s arm during 45-min treatment sessions and is operated using a smartphone app. This study (NCT05769322) aims to evaluate whether frequent use of REN for the acute treatment of migraine in adolescents resulted in a reduction in monthly migraine treatment days (MMTD), as previously demonstrated in adults through a dedicated prevention clinical trial (NCT04828707).MethodsThe study included real-world prospective data from adolescent patients who used REN on at least 10 days every 28-day month, following the REN migraine prevention guideline of an every-other-day pattern. Additional requirements were at least three REN treatment days in each of the two subsequent months. The number of MMTD was used as a proxy measure for the number of monthly migraine days (MMD). The change in MMTD from the first month, taken as a “baseline,” to each of the following months was used to evaluate the presence and size of potential migraine preventive benefits of REN in adolescents.ResultsA total of 83 adolescents were eligible for analysis. The users were 15.9 ± 1.3 years of age (mean ± SD), and 89% of them were female. The results demonstrated a substantial month-to-month reduction in the mean (±SD) number of REN treatment days from 12.6 (±3.2) MMTD in the first month to 9.0 (±4.8) MMTD in the second month (p < 0.001), and a further decrease to 7.4 (±4.2) MMTD in the third month (p < 0.001). This indicates an accumulative reduction of 5.2 (±4.8) mean REN MMTD from the first month to the third month of consecutive REN treatment. The users also reported consistent 2-h acute pain responses in at least 50% of their treated attacks, with 61.9% of the users reported experiencing pain relief, 24.5% reported pain freedom, 67.4% indicated relief in functional disability, and 41.3% reported complete freedom from functional disability.ConclusionThe frequent use of REN among adolescents as an acute treatment for migraine attacks resulted in a decrease in the mean number of monthly treatment days in the subsequent months, suggesting that REN may have potential preventive benefits for migraine in this subpopulation

Enhanced production yields of rVSV-SARS-CoV-2 vaccine using Fibra-Cel® macrocarriers

The COVID-19 pandemic has led to high global demand for vaccines to safeguard public health. To that end, our institute has developed a recombinant viral vector vaccine utilizing a modified vesicular stomatitis virus (VSV) construct, wherein the G protein of VSV is replaced with the spike protein of SARS-CoV-2 (rVSV-ΔG-spike). Previous studies have demonstrated the production of a VSV-based vaccine in Vero cells adsorbed on Cytodex 1 microcarriers or in suspension. However, the titers were limited by both the carrier surface area and shear forces. Here, we describe the development of a bioprocess for rVSV-ΔG-spike production in serum-free Vero cells using porous Fibra-Cel® macrocarriers in fixed-bed BioBLU®320 5p bioreactors, leading to high-end titers. We identified core factors that significantly improved virus production, such as the kinetics of virus production, the use of macrospargers for oxygen supply, and medium replenishment. Implementing these parameters, among others, in a series of GMP production processes improved the titer yields by at least two orders of magnitude (2e9 PFU/mL) over previously reported values. The developed process was highly effective, repeatable, and robust, creating potent and genetically stable vaccine viruses and introducing new opportunities for application in other viral vaccine platforms

The Response to High CO₂ Levels Requires the Neuropeptide Secretion Component HID-1 to Promote Pumping Inhibition

<div><p>Carbon dioxide (CO₂) is a key molecule in many biological processes; however, mechanisms by which organisms sense and respond to high CO₂ levels remain largely unknown. Here we report that acute CO₂ exposure leads to a rapid cessation in the contraction of the pharynx muscles in <i>Caenorhabditis elegans</i>. To uncover the molecular mechanisms underlying this response, we performed a forward genetic screen and found that <i>hid-1</i>, a key component in neuropeptide signaling, regulates this inhibition in muscle contraction. Surprisingly, we found that this <i>hid-1</i>-mediated pathway is independent of any previously known pathways controlling CO₂ avoidance and oxygen sensing. In addition, animals with mutations in <i>unc-31</i> and <i>egl-21</i> (neuropeptide secretion and maturation components) show impaired inhibition of muscle contraction following acute exposure to high CO₂ levels, in further support of our findings. Interestingly, the observed response in the pharynx muscle requires the BAG neurons, which also mediate CO₂ avoidance. This novel <i>hid-1</i>-mediated pathway sheds new light on the physiological effects of high CO₂ levels on animals at the organism-wide level.</p></div

Real-time change detection of steady-state evoked potentials

Steady-state evoked potentials (SSEP) are the electrical activity recorded from the scalp in response to high-rate sensory stimulation. SSEP consist of a constituent frequency component matching the stimulation rate, whose amplitude and phase remain constant with time and are sensitive to functional changes in the stimulated sensory system. Monitoring SSEP during neurosurgical procedures allows identification of an emerging impairment early enough before the damage becomes permanent. In routine practice, SSEP are extracted by averaging of the EEG recordings, allowing detection of neurological changes within approximately a minute. As an alternative to the relatively slow-responding empirical averaging, we present an algorithm that detects changes in the SSEP within seconds. Our system alerts when changes in the SSEP are detected by applying a two-step Generalized Likelihood Ratio Test (GLRT) on the unaveraged EEG recordings. This approach outperforms conventional detection and provides the monitor with a statistical measure of the likelihood that a change occurred, thus enhancing its sensitivity and reliability. The system’s performance is analyzed using Monte Carlo simulations and tested on real EEG data recorded under coma

The inhibition of pumping following exposure to high CO₂ level is independent of molecular pathways that regulate CO₂ avoidance and oxygen sensing.

<p>One-day-old adult <i>C. elegans</i> strains containing mutations in genes that regulate CO₂ avoidance (<b>A, B</b>) or O₂ sensing (<b>C</b>) were exposed to 10% CO₂. The pumping rate was measured under a dissecting microscope during the first minute of exposure to CO₂. In all experiments <i>N</i>≥30 animals. Different groups were compared by one-way ANOVA followed by <i>t</i> test. ***<i>P</i><.001. Error bars indicate SEM.</p

The effect of high CO₂ level on the pharynx requires HID-1 activity in the BAG neurons.

<p>(<b>A</b>) One-day-old adult <i>C. elegans</i> strains containing mutations in <i>unc-31</i> or <i>egl-21</i> genes, which are important for proper neuropeptide secretion and maturation, show a significant rescue of the pumping rate after exposure to 10% CO₂. In contrast, strains with mutations in <i>unc-13</i> or <i>rab-3</i>, which promote synaptic vesicle secretion, do not show a changed pharynx response to 10% CO₂. (<b>B</b>) Transgenic expression of HID-1 in the gut using the gut-specific <i>ges-1</i> promoter (<i>ges-1p</i>-HID-1::GFP) was not sufficient to restore pumping phenotype to wild type after exposure to 10% CO₂. In contrast, transgenic expression of HID-1 in neurons using the <i>rab-3</i> promoter (<i>rab-3p</i>-HID-1::GFP) was sufficient to restore pumping rate after exposure to 10% CO₂ almost back to wild-type levels. Cell-specific expression of HID-1 in the AFD neurons (<i>gcy-8p</i>-HID-1::GFP) or in the amphid and tail ciliated neurons, including ASE neurons (<i>osm-6p</i>-HID-1::GFP), did not restore the CO₂ effect on the pumping back to wild-type levels, whereas cell-specific expression of HID-1 in sensory and pharyngeal neurons (<i>nlp-3p</i>-HID-1::GFP) or in BAG neurons (<i>flp-17p</i>-HID-1::GFP and <i>gcy-33p</i>-HID-1::GFP) was sufficient to restore the effect of high CO₂ level back to the wild-type phenotype. (<b>C</b>) The BAG neurons of wild-type <i>C. elegans</i> expressing <i>gcy-33</i>::GFP were laser ablated and the pharyngeal pumping rate was measured in normal air and 10% CO₂. Similarly, the BAG neurons of <i>flp-17</i>p::HID-1::GFP and <i>gcy-33</i>p::HID-1::GFP strains were laser ablated and the pharyngeal pumping rate subsequently measured. Controls include measurement of the pumping rate in the same <i>C. elegans</i> strains without ablation. (<b>D</b>) Transgenic expression of HID-1 in the BAG neurons of <i>hid-1(sa722);gcy-9(tm2816)</i> animals restores the suppression of pumping in the presence of high CO₂ level. (<b>E</b>) Schematic model of CO₂ response of pharyngeal muscle contraction. The inhibition of muscle contraction in the pharynx is mediated by neuropeptide secretion via dense core vesicles (DCVs) in BAG neurons. The CO₂ response is decreased after starvation. In all experiments <i>N</i>≥30 animals, except in panel C in <i>flp-17p</i>::HID-1::GFP (<i>N</i> = 5) and <i>gcy-33p</i>::HID-1::GFP (<i>N</i> = 10). Different groups were compared by one-way ANOVA followed by <i>t</i> test. ***<i>P</i><.001. Error bars indicate SEM.</p