Enhancing Motor Imagery Decoding in Brain Computer Interfaces using Riemann Tangent Space Mapping and Cross Frequency Coupling

Objective: Motor Imagery (MI) serves as a crucial experimental paradigm within the realm of Brain Computer Interfaces (BCIs), aiming to decoding motor intentions from electroencephalogram (EEG) signals. Method: Drawing inspiration from Riemannian geometry and Cross-Frequency Coupling (CFC), this paper introduces a novel approach termed Riemann Tangent Space Mapping using Dichotomous Filter Bank with Convolutional Neural Network (DFBRTS) to enhance the representation quality and decoding capability pertaining to MI features. DFBRTS first initiates the process by meticulously filtering EEG signals through a Dichotomous Filter Bank, structured in the fashion of a complete binary tree. Subsequently, it employs Riemann Tangent Space Mapping to extract salient EEG signal features within each sub-band. Finally, a lightweight convolutional neural network is employed for further feature extraction and classification, operating under the joint supervision of cross-entropy and center loss. To validate the efficacy, extensive experiments were conducted using DFBRTS on two well-established benchmark datasets: the BCI competition IV 2a (BCIC-IV-2a) dataset and the OpenBMI dataset. The performance of DFBRTS was benchmarked against several state-of-the-art MI decoding methods, alongside other Riemannian geometry-based MI decoding approaches. Results: DFBRTS significantly outperforms other MI decoding algorithms on both datasets, achieving a remarkable classification accuracy of 78.16% for four-class and 71.58% for two-class hold-out classification, as compared to the existing benchmarks.Comment: 22 pages, 7 figure

Improved Motor Imagery Classification Using Adaptive Spatial Filters Based on Particle Swarm Optimization Algorithm

As a typical self-paced brain-computer interface (BCI) system, the motor imagery (MI) BCI has been widely applied in fields such as robot control, stroke rehabilitation, and assistance for patients with stroke or spinal cord injury. Many studies have focused on the traditional spatial filters obtained through the common spatial pattern (CSP) method. However, the CSP method can only obtain fixed spatial filters for specific input signals. Besides, CSP method only focuses on the variance difference of two types of electroencephalogram (EEG) signals, so the decoding ability of EEG signals is limited. To obtain more effective spatial filters for better extraction of spatial features that can improve classification to MI-EEG, this paper proposes an adaptive spatial filter solving method based on particle swarm optimization algorithm (PSO). A training and testing framework based on filter bank and spatial filters (FBCSP-ASP) is designed for MI EEG signal classification. Comparative experiments are conducted on two public datasets (2a and 2b) from BCI competition IV, which show the outstanding average recognition accuracy of FBCSP-ASP. The proposed method has achieved significant performance improvement on MI-BCI. The classification accuracy of the proposed method has reached 74.61% and 81.19% on datasets 2a and 2b, respectively. Compared with the baseline algorithm (FBCSP), the proposed algorithm improves 11.44% and 7.11% on two datasets respectively. Furthermore, the analysis based on mutual information, t-SNE and Shapley values further proves that ASP features have excellent decoding ability for MI-EEG signals, and explains the improvement of classification performance by the introduction of ASP features.Comment: 25 pages, 8 figure

The role of forward osmosis and microfiltration in an integrated osmotic-microfiltration membrane bioreactor system

This study investigates the performance of an integrated osmotic and microfiltration membrane bioreactor (O/MF-MBR) system for wastewater treatment and reclamation. The O/MF-MBR system simultaneously used microfiltration (MF) and forward osmosis (FO) membranes to extract water from the mixed liquor of an aerobic bioreactor. The MF membrane facilitated the bleeding of dissolved inorganic salts and thus prevented the build-up of salinity in the bioreactor. As a result, sludge production and microbial activity were relatively stable over 60 days of operation. Compared to MF, the FO process produced a better permeate quality in terms of nutrients, total organic carbon, as well as hydrophilic and biologically persistent trace organic chemicals (TrOCs). The high rejection by the FO membrane also led to accumulation of hydrophilic and biologically persistent TrOCs in the bioreactor, consequently increasing their concentration in the MF permeate. On the other hand, hydrophobic and readily biodegradable TrOCs were minimally detected in both MF and FO permeates, with no clear difference in the removal efficiencies between two processes

Simultaneous nitrification/denitrification and trace organic contaminant (TrOC) removal by an anoxic-aerobic membrane bioreactor (MBR)

Simultaneous nitrification/denitrification and trace organic contaminant (TrOC) removal during wastewater treatment by an integrated anoxic-aerobic MBR was examined. A set of 30 compounds was selected to represent TrOCs that occur ubiquitously in domestic wastewater. The system achieved over 95% total organic carbon (TOC) and over 80% total nitrogen (TN) removal. In addition, 21 of the 30 TrOCs investigated here were removed by over 90%. Low oxidation reduction potential (i.e., anoxic/anaerobic) regimes were conducive to moderate to high (50% to 90%) removal of nine TrOCs. These included four pharmaceuticals and personal care products (primidone, metronidazole, triclosan, and amitriptyline), one steroid hormone (17β-estradiol-17-acetate), one industrial chemical (4-tert-octylphenol) and all three selected UV filters (benzophenone, oxybenzone, and octocrylene). Internal recirculation between the anoxic and aerobic bioreactors was essential for anoxic removal of remaining TrOCs. A major role of the aerobic MBR for TOC, TN, and TrOC removal was observed

Enhancement of trace organic contaminant degradation by crude enzyme extract from Trametes versicolor culture: Effect of mediator type and concentration

The performance of two redox mediating compounds, namely 1-hydroxybenzotriazole (HBT) and syringaldehyde (SA), was compared in terms of enhancement of enzymatic degradation of a diverse set of 14 phenolic and 16 non-phenolic trace organic contaminants (TrOCs) and the toxicity of the treated media. Extracellular enzyme extract (predominantly containing laccase) from Trametes versicolor culture achieved efficient degradation (70-95%) of nine phenolic and one non-phenolic TrOCs. Mediator dosing extended the spectrum of efficiently degraded TrOCs to 13 phenolic and three non-phenolic compounds, with moderate improvements in removal of a few other non-phenolic compounds. TrOC removal efficiency improved significantly as the HBT dose was increased from 0.1 to 0.5 mM, while SA achieved similar removal over dosage range of 0.1-1 mM. A particular concern was the toxicity of the treated media (1200-2200 times that of the control) for all SA dosages applied. Overall, HBT at a concentration of 0.5 mM achieved the best removal without raising concern regarding toxicity of the treated media. The results are discussed in the light of the redox potential of the enzyme-mediator cocktail, the balance between the stability and reactivity of the radicals generated and their cytotoxic effects

Clinical Study Efficacy of Combined Laparoscopic and Hysteroscopic Repair of Post-Cesarean Section Uterine Diverticulum: A Retrospective Analysis

Background. Diverticulum, one of the long-term sequelae of cesarean section, can cause abnormal uterine bleeding and increase the risk of uterine scar rupture. In this study, we aimed to evaluate the efficacy of combined laparoscopic and hysteroscopic repair, a newly occurring method, treating post-cesarean section uterine scar diverticulum. Methods. Data relating to 40 patients with post-cesarean section uterine diverticulum who underwent combined laparoscopic and hysteroscopic repair were retrospectively analyzed. Preoperative clinical manifestations, size of uterine defects, thickness of the lower uterine segment (LUS), and duration of menstruation were compared with follow-up findings at 1, 3, and 6 months after surgery. Results. The average preoperative length and width of uterine diverticula and thickness of the lower uterine segment were recorded and analyzed. The average durations of menstruations at 1, 3, and 6 months after surgery were significantly shorter than the preoperative one ( < 0.05), respectively. At 6 months after surgery, the overall success improvement rate of surgery was 90% (36/40). Three patients (3/40 = 7.5%) developed partial improvement, and 1/40 (2.5%) was lost to follow-up. Conclusions. Our findings showed that combined treatment with laparoscopy and hysteroscopy was an effective method for the repair of post-cesarean section uterine diverticulum

Identification and characterization of phenolic compounds in hydromethanolic extracts of sorghum wholegrains by LC-ESI-MSn

Hydromethanolic extracts of brown, red, and white sorghum whole grains were analysed by LC-MSn in negative ESI mode within the range m/z 150–550 amu. Besides the flavonoids already reported in sorghum, a number of flavonoids were also identified in the sorghum grain for the first time, including flavanones, flavonols and flavanonols, and flavan-3-ol derivatives. Various phenylpropane glycerides were also found in the sorghum grain, the majority of them are reported here for the first time, and a few of them were detected with abundant peaks in the extracts, indicating they are another important class of phenolic compounds in sorghum. In addition, phenolamides were also found in sorghum grain, which have not been reported before, and dicaffeoyl spermidine was detected in high abundance in the extracts of all three type sorghum grains. These results confirmed that sorghum is a rich source of various phenolic compounds

Dual Antiplatelet Treatment up to 72 Hours after Ischemic Stroke

BackgroundDual antiplatelet treatment has been shown to reduce recurrence of stroke compared to aspirin alone when initiated early after an acute stroke. The effect of clopidogrel and aspirin versus aspirin alone within 72 hours of acute cerebral ischemia from atherosclerosis has not been well studied.MethodsWe conducted a randomized, double-blind, placebo-controlled, 2-by-2 factorial trial in patients with mild ischemic stroke or high-risk transient ischemic attack (TIA) of presumed atherosclerotic cause, not receiving thrombolysis or thrombectomy in 222 hospitals in China. Patients were randomly assigned within 72 hours after symptom onset in a 1:1 ratio, to receive clopidogrel (300mg on day 1, 75mg daily on days 2-90) and aspirin (100-300mg on day1, 100mg daily on days 2-21), or clopidogrel placebo and aspirin (100-300mg on day1, 100mg daily on days 2-90). There was no interaction between this component of the factorial trial design trial and a second part that tested immediate vs delayed stain treatment and is reported separately. The primary efficacy outcome was a new stroke, and the primary safety outcome was moderate-to-severe bleeding, both within 90 days.ResultsA total of 6100 patients were enrolled, 3050 assigned to each trial group. The qualifying event for enrollment was TIA in 13%. Approximately 13% of patients were assigned to a treatment group within 24 hours and 87% were assigned between 24 and 72 hours of onset of stroke. A new stroke occurred in 222 (7.3%) in the clopidogrel-aspirin group, and 279 (9.2%) in the aspirin group (hazard ratio, 0.79; 95% confidence interval [CI], 0.66-0.94; P=0.008). Moderate-to-severe bleeding occurred in 27 (0.9%) and 13 patients (0.4%), respectively (hazard ratio, 2.08; 95% CI, 1.07-4.04, P=0.03).ConclusionsAmong patients with mild ischemic stroke or high-risk TIA of presumed atherosclerotic cause, combined clopidogrel-aspirin initiated within 72 hours of onset was superior to aspirin alone in reducing the risk of new stroke at 90 days but was associated with a low but increased risk of moderate-to-severe bleeding