Detection of virtual reality motion sickness based on EEG using asymmetry of entropy and cross-frequency coupling.

The existence of Virtual Reality Motion Sickness (VRMS) is a key factor restricting the further development of the VR industry, and the premise to solve this problem is to be able to accurately and effectively detect its occurrence. In view of the current lack of high-accuracy and effective detection methods, this paper proposes a VRMS detection method based on entropy asymmetry and cross-frequency coupling value asymmetry of EEG. First of all, the EEG of the four selected pairs of electrodes on the bilateral brain are subjected to Multivariate Variational Mode Decomposition (MVMD) respectively, and three types of entropy values on the low-frequency and high-frequency components are calculated, namely approximate entropy, fuzzy entropy and permutation entropy, as well as three types of phase-amplitude coupling features between the low-frequency and high-frequency components, namely the mean value, standard deviation and correlation coefficient; Secondly, the difference of the entropies and the cross-frequency coupling features between the left electrodes and the right electrodes are calculated; Finally, the final feature set are selected via t-test and fed into the SVM for classification, thus realizing the automatic detection of VRMS. The results show that the three classification indexes under this method, i.e., accuracy, sensitivity and specificity, reach 99.5 %, 99.3 % and 99.7 %, respectively, and the value of the area under the ROC curve reached 1, which proves that this method can be an effective indicator for detecting the occurrence of VRMS.

Preperitoneal pelvic balloon tamponade-an effective intervention to control pelvic injury hemorrhage in a swine model.

Objective: This study aimed to estimate the effects of the volume of preperitoneal balloon (PPB) on arterial and venous hemorrhage in a swine pelvic fracture model. Methods: Twenty-four swine were randomized into 0-mL, 500-mL, 800-mL, and 1000-mL intra-hematoma PPB groups. They were subjected to open-book pelvic fracture and reproducible injuries in the external iliac artery and vein. The pelvic binder and IH-PPBs with different volumes of fluid were applied to control the active hemorrhage after arterial and venous injuries. The survival time and rate during 60-min observation and digital subtraction angiography (DSA) images were the primary endpoints in this study. Secondary endpoints included survival rate within 70 min, peritoneal pressure, hemodynamics, blood loss, infusion fluid, blood pH, and lactate concentration. Results: Our results indicated that the 800-mL and 1000-mL groups had a higher survival rate (0%, 50%, 100% and 100% for 0, 500, 800, and 1000-mL groups respectively; p < 0.0001) and longer survival time (13.83 ± 2.64, 24.50 ± 6.29, 55.00 ± 6.33, and 60.00 ± 0.00 min for 0, 500, 800, and 1,000 groups respectively; p < 0.0005) than the 0-mL or 500-mL groups during the 60 min observation. Contrastingly, survival rate and time were comparable between 800-mL and 1000-mL groups during the 60-min observation. The IH-PPB volume was associated with an increase in the pressure of the balloon and the preperitoneal pressure but had no effect on the bladder pressure. Lastly, the 1000-mL group had a higher mean arterial pressure and systemic vascular resistance than the 800-mL group. Conclusion: IH-PPB volume-dependently controls vascular bleeding after pelvic fracture in the swine model. IH-PPB with a volume of 800 mL and 1000 mL efficiently managed pelvic fracture-associated arterial and venous hemorrhage and enhanced survival time and rate in the swine model without evidences of visceral injury.

EEG classification model for virtual reality motion sickness based on multi-scale CNN feature correlation.

BACKGROUND: Virtual reality motion sickness (VRMS) is a key issue hindering the development of virtual reality technology, and accurate detection of its occurrence is the first prerequisite for solving the issue. OBJECTIVE: In this paper, a convolutional neural network (CNN) EEG detection model based on multi-scale feature correlation is proposed for detecting VRMS. METHODS: The model uses multi-scale 1D convolutional layers to extract multi-scale temporal features from the multi-lead EEG data, and then calculates the feature correlations of the extracted multi-scale features among all the leads to form the feature adjacent matrixes, which converts the time-domain features to correlation-based brain network features, thus strengthen the feature representation. Finally, the correlation features of each layer are fused. The fused features are then fed into the channel attention module to filter the channels and classify them using a fully connected network. Finally, we recruit subjects to experience 6 different modes of virtual roller coaster scenes, and collect resting EEG data before and after the task to verify the model. RESULTS: The results show that the accuracy, precision, recall and F1-score of this model for the recognition of VRMS are 98.66 %, 98.65 %, 98.68 %, and 98.66 %, respectively. The proposed model outperforms the current classic and advanced EEG recognition models. SIGNIFICANCE: It shows that this model can be used for the recognition of VRMS based on the resting state EEG.

RESUSCITATIVE RECTAL BALLOON COMPRESSION COMBINED WITH PELVIC BINDER EFFICIENTLY CONTROLLED FATAL VENOUS HEMORRHAGE IN A HEMODYNAMICALLY UNSTABLE PELVIC FRACTURE CANINE MODEL.

ABSTRACT: Objective: This study evaluated the feasibility of a combination of pelvic binder and rectal balloon compression in managing fatal venous hemorrhage in a canine model of pelvic fracture. Methods: Rectums from humans (rectal cancer patients), swine, and canines were retrieved to determine their elasticity by measuring their stress and strain. Canines were selected as the animal model in this study because their rectum demonstrated more reversible strain than swine rectum. Doppler ultrasound was used to assess the effect of rectal balloon volume on the blood flow of pelvic iliac blood vessels in three canines. A rectal balloon of 250 mL was chosen to control pelvic venous bleeding as it could provide a peak effect in reducing the blood flow of bilateral internal iliac veins. Then, the open-book pelvic fracture with fatal bleeding of both internal iliac veins animal model was built. The animals were divided into four groups after the modeled surgery to undergo no treatment, pelvic binder, rectal balloon compression, or a combination of pelvic binder and rectal balloon compression. The treatment efficacy was evaluated based on their survival time, survival rate, blood loss, bleeding rate, infusion rate, blood pH, lactate concentration, the stability of hemodynamics, blood loss, and fluid infusion volume. Results: Our results showed that after the reproducible injuries in both internal iliac veins, the combination of pelvic binder and rectal balloon compression was associated with the best survival rate and survival time compared with the other treatment groups. In addition, the combination of pelvic binder and rectal balloon compression exhibited more stable hemodynamics than the pelvic binder or rectal balloon compression treatment alone. Conclusions: This study demonstrated the potential feasibility of using pelvic binder combined with rectal balloon compression to manage the fatal venous bleeding in pelvic fractures.

Conductive and elastic bottlebrush elastomers for ultrasoft electronics.

Understanding biological systems and mimicking their functions require electronic tools that can interact with biological tissues with matched softness. These tools involve biointerfacing materials that should concurrently match the softness of biological tissue and exhibit suitable electrical conductivities for recording and reading bioelectronic signals. However, commonly employed intrinsically soft and stretchable materials usually contain solvents that limit stability for long-term use or possess low electronic conductivity. To date, an ultrasoft (i.e., Young's modulus <30 kPa), conductive, and solvent-free elastomer does not exist. Additionally, integrating such ultrasoft and conductive materials into electronic devices is poorly explored. This article reports a solvent-free, ultrasoft and conductive PDMS bottlebrush elastomer (BBE) composite with single-wall carbon nanotubes (SWCNTs) as conductive fillers. The conductive SWCNT/BBE with a filler concentration of 0.4 - 0.6 wt% reveals an ultralow Young's modulus (<11 kPa) and satisfactory conductivity (>2 S/m) as well as adhesion property. Furthermore, we fabricate ultrasoft electronics based on laser cutting and 3D printing of conductive and non-conductive BBEs and demonstrate their potential applications in wearable sensing, soft robotics, and electrophysiological recording.

Efficacy and safety of free medial plantar flap in repair of the high-voltage electrical burns in hands.

PURPOSE: The purpose of this work was to validate the efficacy and safety of free medial plantar flap in repair of hand wounds resulted from high-voltage electrical burn. METHODS: 22 patients with high-voltage electrical burn wounds were retrieved between July 2016 and July 2018 in the Affiliated Zhengzhou Central Hospital of Zhengzhou University. All the wounds were the entrance of high-voltage electrical current. After thorough debridement, the blood vessels, nerves, tendons, joints were exposed to defects with different degrees. The soft tissue defects were repaired with the free medial plantar flap repair in 12 patients and medium-thickness skin graft in 10 patients. Postoperative management was similar between the two groups. RESULTS: All the operations were completed within 6 h. In the free medial plantar flap group, the mean follow-up period was (11.3 ± 2.4) months, ranging from 9 to 15 months, and all flaps survived; there were no vessel crises. Flaps of 10 patients healed without any complications, and local necrosis occurred in two cases, with healing after debridement. The two-point discrimination (TPD) was 7.0-11.0 mm, and the mean DASH score was 45.6 ± 7.4. In the medium-thickness skin graft group, the mean follow-up period was (10.9 ± 1.8) months. All flaps survived, and local contracture occurred in 3 cases. The TPD was 8.0-11.0 mm, and the mean DASH score was 60.7 ± 9.3. CONCLUSIONS: The free medial plantar flap is an ideal option for repairing the hand soft defects resulted from the high-voltage electrical burn.