Spatial variation in automated burst suppression detection in pharmacologically induced coma

Burst suppression is actively studied as a control signal to guide anesthetic dosing in patients undergoing medically induced coma. The ability to automatically identify periods of EEG suppression and compactly summarize the depth of coma using the burst suppression probability (BSP) is crucial to effective and safe monitoring and control of medical coma. Current literature however does not explicitly account for the potential variation in burst suppression parameters across different scalp locations. In this study we analyzed standard 19-channel EEG recordings from 8 patients with refractory status epilepticus who underwent pharmacologically induced burst suppression as medical treatment for refractory seizures. We found that although burst suppression is generally considered a global phenomenon, BSP obtained using a previously validated algorithm varies systematically across different channels. A global representation of information from individual channels is proposed that takes into account the burst suppression characteristics recorded at multiple electrodes. BSP computed from this representative burst suppression pattern may be more resilient to noise and a better representation of the brain state of patients. Multichannel data integration may enhance the reliability of estimates of the depth of medical coma.National Institutes of Health (U.S.) (Grant K23 NS090900)National Institute of Neurological Diseases and Stroke (U.S.) (Grant K23 NS090900)National Institutes of Health (U.S.) (Grant DP2-OD006454)National Institutes of Health (U.S.) (Grant TROI-GMI04948

Sciences for The 2.5-meter Wide Field Survey Telescope (WFST)

The Wide Field Survey Telescope (WFST) is a dedicated photometric survey facility under construction jointly by the University of Science and Technology of China and Purple Mountain Observatory. It is equipped with a primary mirror of 2.5m in diameter, an active optical system, and a mosaic CCD camera of 0.73 Gpix on the main focus plane to achieve high-quality imaging over a field of view of 6.5 square degrees. The installation of WFST in the Lenghu observing site is planned to happen in the summer of 2023, and the operation is scheduled to commence within three months afterward. WFST will scan the northern sky in four optical bands (u, g, r, and i) at cadences from hourly/daily to semi-weekly in the deep high-cadence survey (DHS) and the wide field survey (WFS) programs, respectively. WFS reaches a depth of 22.27, 23.32, 22.84, and 22.31 in AB magnitudes in a nominal 30-second exposure in the four bands during a photometric night, respectively, enabling us to search tremendous amount of transients in the low-z universe and systematically investigate the variability of Galactic and extragalactic objects. Intranight 90s exposures as deep as 23 and 24 mag in u and g bands via DHS provide a unique opportunity to facilitate explorations of energetic transients in demand for high sensitivity, including the electromagnetic counterparts of gravitational-wave events detected by the second/third-generation GW detectors, supernovae within a few hours of their explosions, tidal disruption events and luminous fast optical transients even beyond a redshift of 1. Meanwhile, the final 6-year co-added images, anticipated to reach g about 25.5 mag in WFS or even deeper by 1.5 mag in DHS, will be of significant value to general Galactic and extragalactic sciences. The highly uniform legacy surveys of WFST will also serve as an indispensable complement to those of LSST which monitors the southern sky.Comment: 46 pages, submitted to SCMP

Numerical simulation of flow and heat transfer performance in branch and combined-branch microchannel

The pressure drop at the inlet and outlet of rectangular microchannel is large, and the temperature distribution is uneven; Fractal microchannel is limited by fractal dimension and the number of branches, so its application scope is narrow. A branch and combined-branch microchannel heat sink was designed by combining the advantages of rectangular microchannel and fractal microchannel, and Fluent software was used to numerically simulate its heat dissipation process to study the flow and heat transfer performance when the branch tilt angle inside the microchannel changes. The results show that at the heat flow of 100 W/cm2, when the Re is 970 and the branch tilt angle is 90°, the average temperature of the branch and combined-branch microchannel decreases by 11.9 K, the maximum temperature decreases by 14.2 K, the Nu increases by 85.7%, and the performance evaluation criterion (PEC) is also the best by reaching 1.44. The introduction of branches can increase the heat transfer area inside the microchannel, form a new boundary layer, and generate vortices at the inner side of the branch, effectively improving the heat transfer performance of the microchannel heat sinks, which provides new theoretical basis for optimizing the design of microchannels

Influence of diabetes on the risk of deep vein thrombosis of patients after total knee arthroplasty: a meta-analysis

Abstract Background Previous studies evaluating the influence of diabetes on the risk of deep vein thrombosis (DVT) after total knee arthroplasty (TKA) showed inconsistent results. The aim of the study was to systematically evaluate the association between diabetes and DVT after TKA in a meta-analysis. Methods An extensive search was conducted in PubMed, Embase, and Web of Science to identify relevant cohort studies. Random-effects models were employed to pool the results after taking account of the potential influence of heterogeneity. Results Thirteen cohort studies involving 546,156 patients receiving TKA were included, with 71,110 (13.0%) diabetic patients before surgery and 1479 (2.1%) patients diagnosed as DVT after surgery. Overall, diabetes was associated with an increased risk of DVT after TKA (risk ratio [RR]: 1.43, 95% confidence interval [CI]: 1.12–1.84, p = 0.004; I 2 = 44%). Sensitivity analysis limited to studies with chemoprophylaxis (RR: 1.96, 95% CI: 1.50–2.54), and studies with multivariate analysis (RR: 1.54, 95% CI: 1.12–2.11) showed consistent results. Subgroup analysis showed that diabetes was associated with higher risk of postoperative DVT in Asian countries (RR: 1.93, 95% CI: 1.49–2.52, p < 0.001; I 2 = 1%) but not in Western countries (RR: 1.07, 95% CI: 0.86–1.34, p = 0.52; I 2 = 0%; p for subgroup difference < 0.001). Conclusion Diabetes may be a risk factor for DVT after TKA, even with the chemoprophylaxis of anticoagulants. The association between diabetes and DVT after TKA may be more remarkable in patients from Asian countries

Breakup Dynamics of Droplets in Symmetric Y-Junction Microchannels

The experimental method is used to study the droplet breaking characteristics of an immiscible liquid&ndash;liquid t8wo-phase fluid in symmetric Y-junction microchannels. Silicone oil is used as the dispersed phase and distilled water containing 0.5% SDS is used as the continuous phase. Three breakup behaviors were observed: breakup with permanent obstruction, breakup with gaps, and no breakup. Two stages of the change of the neck width of the sub-droplet during the breakup process were discovered: a rapid breakup stage and a thread breakup stage. The effect of the breakup behavior on the flow pattern was investigated and it was found that the breakup behavior of the droplets made the slug flow area smaller; further, a new flow pattern was observed, being droplet flow. The length of the sub-droplet increases with an increase of the volume flow rate of the dispersed phase and the ratio of the volume flow rate of the dispersed phase to the continuous phase, while decreasing with an increase of the volume flow rate and the capillary number of the continuous phase. Based on the influence of the two-phase flow parameters on the length of the sub-droplet, a correlation formula for the length of the sub-droplet with good predictive performance is proposed

Breakup Dynamics of Droplets in Symmetric Y-Junction Microchannels

The experimental method is used to study the droplet breaking characteristics of an immiscible liquid–liquid t8wo-phase fluid in symmetric Y-junction microchannels. Silicone oil is used as the dispersed phase and distilled water containing 0.5% SDS is used as the continuous phase. Three breakup behaviors were observed: breakup with permanent obstruction, breakup with gaps, and no breakup. Two stages of the change of the neck width of the sub-droplet during the breakup process were discovered: a rapid breakup stage and a thread breakup stage. The effect of the breakup behavior on the flow pattern was investigated and it was found that the breakup behavior of the droplets made the slug flow area smaller; further, a new flow pattern was observed, being droplet flow. The length of the sub-droplet increases with an increase of the volume flow rate of the dispersed phase and the ratio of the volume flow rate of the dispersed phase to the continuous phase, while decreasing with an increase of the volume flow rate and the capillary number of the continuous phase. Based on the influence of the two-phase flow parameters on the length of the sub-droplet, a correlation formula for the length of the sub-droplet with good predictive performance is proposed

A hidden semi-Markov model for estimating burst suppression EEG

Burst suppression is an electroencephalogram (EEG) pattern associated with profoundly inactivated brain states characterized by cerebral metabolic depression. This pattern is distinguished by short-duration band-limited electrical activity (bursts) interspersed between relatively near-isoelectric periods (suppressions). Prior work in neurophysiology suggests that burst and suppression segments are respectively associated with consumption and regeneration of adenosine triphosphate resource in cortical networks. This indicates that once a suppression (or, burst) segment begins, the propensity to switch out of the state gradually increases with duration spent in the state. Prior EEG monitoring frameworks that track the brain state during burst suppression by tracking the estimated fraction of time spent in suppression, relative to bursts, do not incorporate this information. In this work, we incorporate this information within a hidden semi-Markov model (HSMM) wherein two states (burst & suppression) stochastically switch between each other using sojourn-time dependent transition probabilities. We demonstrate the HSMM's utility in analyzing clinical data by estimating the state probabilities, the optimal state sequence, and the brain's metabolic activation level characterized by parameters governing sojourn-time dependence in transition probabilities. The HSMM-based approach proposed here provides a novel statistical framework that advances the state-of-the-art in analyzing burst suppression EEG