COVID-19 and its implications for thrombosis and anticoagulation

Severe acute respiratory syndrome coronavirus 2, coronavirus disease 2019 (COVID-19)-induced infection can be associated with a coagulopathy, findings consistent with infection-induced inflammatory changes as observed in patients with disseminated intravascular coagulopathy (DIC). The lack of prior immunity to COVID-19 has resulted in large numbers of infected patients across the globe and uncertainty regarding management of the complications that arise in the course of this viral illness. The lungs are the target organ for COVID-19; patients develop acute lung injury that can progress to respiratory failure, although multiorgan failure can also occur. The initial coagulopathy of COVID-19 presents with prominent elevation of D-dimer and fibrin/fibrinogen-degradation products, whereas abnormalities in prothrombin time, partial thromboplastin time, and platelet counts are relatively uncommon in initial presentations. Coagulation test screening, including the measurement of D-dimer and fibrinogen levels, is suggested. COVID-19–associated coagulopathy should be managed as it would be for any critically ill patient, following the established practice of using thromboembolic prophylaxis for critically ill hospitalized patients, and standard supportive care measures for those with sepsis-induced coagulopathy or DIC. Although D-dimer, sepsis physiology, and consumptive coagulopathy are indicators of mortality, current data do not suggest the use of full-intensity anticoagulation doses unless otherwise clinically indicated. Even though there is an associated coagulopathy with COVID-19, bleeding manifestations, even in those with DIC, have not been reported. If bleeding does occur, standard guidelines for the management of DIC and bleeding should be followed.

High-Resolution Metabolic Mapping of the Cerebellum Using a Zoomed Magnetic Resonance Spectroscopic Imaging

PurposeThe human cerebellum plays an important role in functional activity cerebrum which is ranging from motor to cognitive activities since due to its relaying role between spinal cord and cerebrum. The cerebellum poses many challenges to magnetic resonance spectroscopic imaging (MRSI) due to the caudal location, the susceptibility to physiological artifacts and partial volume artifact due to its complex anatomical structure. Thus, in present study, we propose a high-resolution MRSI acquisition scheme for the cerebellum.MethodsA zoomed or reduced-field of view (rFOV) metabolite-cycled full-intensity magnetic resonance spectroscopic imaging (MRSI) at 3T with a nominal resolution of 62.5 μL was developed. Single-slice rFOV MRSI data were acquired from the cerebellum of 5 healthy subjects with a nominal resolution of 2.5□×□2.5□mm2 in 9□minutes 36. Spectra were quantified with LCModel. A spatially unbiased atlas template of the cerebellum was used for analyzing metabolite distributions in the cerebellum.ResultsThe high quality of the achieved spectra enabled to generate a high-resolution metabolic map of total N-acetylaspartate, total creatine, total choline, glutamate+glutamine and myo-inositol with Cramér-Rao lower bounds below 50%. A spatially unbiased atlas template of the cerebellum-based region of interest (ROIs) analysis resulted in spatially dependent metabolite distributions in 9 ROIs. The group-averaging across subjects in the Montreal Neurological Institute-152 template space allowed to generate a very high-resolution metabolite maps in the cerebellum.ConclusionThese findings indicate that very high-resolution metabolite probing of cerebellum is feasible using rFOV or zoomed MRSI at 3T.

Going down to the crossroads: popular music and transformative magic

If there is a single narrative that captures the modern understanding of transformative crossroads magic it is the spurious fable of the selling of Robert Johnson's soul. When, in the palaeoanthropology of 20th century rock and roll music, the biographers of the short-lived blues legend claimed that he had been down to the Dockery Plantation crossroads at midnight to sell his soul to the Devil in exchange for guitar skills, they were perhaps unwitting witnesses to the deep history of myth and ritual that has long been associated with the transformative space of the crossroads. They were not lacking in foresight, however, about the way in which such a claim would enhance their subject's credibility. The value of such a sulphurous reputation for a musician is not merely a recent phenomenon but also has historical precedents. A hundred years before Johnson (who lived 1911–1938), the guitarist and violinist Niccolo Paganini (1782–1840) was considered such a suspiciously devilish virtuoso that his audiences were reputed to cross themselves before his concerts in hope of protection from subtle demonic influence. One audience member even fled a concert after reporting seeing the Devil himself aiding Paganini's performance. Going a little further back, Giuseppe Tartini (1692–1770) explained of his best-known sonata, The Devil's Trill (1713), that he had ‘written down the piece after waking from a particularly vivid dream of the Devil playing a violin with ferocious virtuosity’, and claimed that it was ‘but a shadow of what he had witnessed in the dream, for he was unable to capture on the page the Devil's full intensity’. His long career was certainly not harmed by this youthful excursion into Hell.

Determining the duration of an ultra-intense laser pulse directly in its focus

Ultra-intense lasers facilitate studies of matter and particle dynamics at unprecedented electromagnetic field strengths. In order to quantify these studies, precise knowledge of the laser’s spatiotemporal shape is required. Due to material damage, however, conventional metrology devices are inapplicable at highest intensities, limiting laser metrology there to indirect schemes at attenuated intensities. Direct metrology, capable of benchmarking these methods, thus far only provides static properties of short-pulsed lasers with no scheme suggested to extract dynamical laser properties. Most notably, this leaves an ultra-intense laser pulse’s duration in its focus unknown at full intensity. Here we demonstrate how the electromagnetic radiation pattern emitted by an electron bunch with a temporal energy chirp colliding with the laser pulse depends on the laser’s pulse duration. This could eventually facilitate to determine the pulse’s temporal duration directly in its focus at full intensity, in an example case to an accuracy of order 10% for fs-pulses, indicating the possibility of an order-of magnitude estimation of this previously inaccessible parameter.

The Influence of Simulated Sunlight on the Inactivation of Influenza Virus in Aerosols

Background Environmental parameters, including sunlight levels, are known to affect the survival of many microorganisms in aerosols. However, the impact of sunlight on the survival of influenza virus in aerosols has not been previously quantified. Methods The present study examined the influence of simulated sunlight on the survival of influenza virus in aerosols at both 20% and 70% relative humidity using an environmentally controlled rotating drum aerosol chamber. Results Measured decay rates were dependent on the level of simulated sunlight, but they were not significantly different between the 2 relative humidity levels tested. In darkness, the average decay constant was 0.02 ± 0.06 min−1, equivalent to a half-life of 31.6 minutes. However, at full intensity simulated sunlight, the mean decay constant was 0.29 ± 0.09 min−1, equivalent to a half-life of approximately 2.4 minutes. Conclusions These results are consistent with epidemiological findings that sunlight levels are inversely correlated with influenza transmission, and they can be used to better understand the potential for the virus to spread under varied environmental conditions.

Network-targeted stimulation engages neurobehavioral hallmarks of age-related memory decline

ObjectiveTo test whether targeting hippocampal-cortical brain networks with high-frequency transcranial magnetic stimulation in older adults influences behavioral and neural measures characteristic of age-related memory impairment.MethodsFifteen adults aged 64 to 80 years (mean = 72 years) completed a single-blind, sham-controlled experiment. Stimulation targets in parietal cortex were determined based on fMRI connectivity with the hippocampus. Recollection and recognition memory were assessed after 5 consecutive daily sessions of full-intensity stimulation vs low-intensity sham stimulation using a within-subjects crossover design. Neural correlates of recollection and recognition memory formation were obtained via fMRI, measured within the targeted hippocampal-cortical network vs a control frontal-parietal network. These outcomes were measured approximately 24 hours after the final stimulation session.ResultsRecollection was specifically impaired in older adults compared to a young-adult control sample at baseline. Relative to sham, stimulation improved recollection to a greater extent than recognition. Stimulation increased recollection fMRI signals throughout the hippocampal-cortical network, including at the targeted location of the hippocampus. Effects of stimulation on fMRI recollection signals were greater than those for recognition and were greater in the targeted network compared to the control network.ConclusionsAge-related recollection impairments were causally related to hippocampal-cortical network function in older adults. Stimulation selectively modified neural and behavioral hallmarks of age-related memory impairment, indicating effective engagement of memory intervention targets in older adults.

Full-intensity waveform inversion

Many full-waveform inversion schemes are based on the iterative perturbation theory to fit the observed waveforms. When the observed waveforms lack low frequencies, those schemes may encounter convergence problems due to cycle skipping when the initial velocity model is far from the true model. To mitigate this difficulty, we have developed a new objective function that fits the seismic-waveform intensity, so the dependence of the starting model can be reduced. The waveform intensity is proportional to the square of its amplitude. Forming the intensity using the waveform is a nonlinear operation, which separates the original waveform spectrum into an ultra-low-frequency part and a higher frequency part, even for data that originally do not have low-frequency contents. Therefore, conducting multiscale inversions starting from ultra-low-frequency intensity data can largely avoid the cycle-skipping problem. We formulate the intensity objective function, the minimization process, and the gradient. Using numerical examples, we determine that the proposed method was very promising and could invert for the model using data lacking low-frequency information.