Developing an AI-assisted digital auscultation tool for automatic assessment of the severity of mitral regurgitation: protocol for a cross-sectional, non-interventional study.

INTRODUCTION: Mitral regurgitation (MR) is the most common valvular heart disorder, with a morbidity rate of 2.5%. While echocardiography is commonly used in assessing MR, it has many limitations, especially for large-scale MR screening. Cardiac auscultation with electronic stethoscope and artificial intelligence (AI) can be a fast and economical modality for assessing MR severity. Our objectives are (1) to establish a deep neural network (DNN)-based cardiac auscultation method for assessing the severity of MR; and (2) to quantitatively measure the performance of the developed AI-based MR assessment method by virtual clinical trial. METHODS AND ANALYSIS: In a cross-sectional design, phonocardiogram will be recorded at the mitral valve auscultation area of outpatients. The enrolled patients will be checked by echocardiography to confirm the diagnosis of MR or no MR. Echocardiographic parameters will be used as gold standard to assess the severity of MR, classified into four levels: none, mild, moderate and severe. The study consists of two stages. First, an MR-related cardiac sound database will be created on which a DNN-based MR severity classifier will be trained. The automatic MR severity classifier will be integrated with the Smartho-D2 electronic stethoscope. Second, the performance of the developed smart device will be assessed in an independent clinical validation data set. Sensitivity, specificity, precision, accuracy and F1 score of the developed smart MR assessment device will be evaluated. Agreement on the performance of the smart device between cardiologist users and patient users will be inspected. The interpretability of the developed model will also be studied with statistical comparisons of occlusion map-guided variables among the four severity groups. ETHICS AND DISSEMINATION: The study protocol was approved by the Medical Ethics Committee of Huzhou Central Hospital, China (registration number: 202302009-01). Informed consent is required from all participants. Dissemination will be through conference presentations and peer-reviewed journals. TRIAL REGISTRATION NUMBER: ChiCTR2300069496.

Stellate ganglion block alleviates postoperative sleep disturbance in patients undergoing radical surgery for gastrointestinal malignancies.

STUDY OBJECTIVES: We explored the effects of stellate ganglion block on postoperative sleep disturbance in patients scheduled to undergo radical surgery for gastrointestinal malignancies. METHODS: Forty such patients were randomly assigned to the control group (Group C) or the preoperative stellate ganglion block treatment group (Group S). Using actigraphy, sleep quality was evaluated on the first night before the operation and first, second, and third postoperative nights. The Pittsburgh Sleep Quality Index scale was used for sleep state assessment on 1 day preoperatively and the first, second, third, fifth, and seventh days postoperatively. Plasma interleukin (IL)-1, IL-6, and IL-10 and melatonin levels were checked at 1 day preoperatively and the first and third days postoperatively. Mean arterial pressure, heart rate, and pulse oxygen saturation (SpO2) were recorded before general anesthesia induction, immediately after tracheal intubation, at the beginning of the operation, 1 and 2 hours after the beginning of the operation, at the end of the operation, immediately after extubation, and 30 minutes after transfer to the postanesthesia care unit. RESULTS: Compared with Group C, in Group S sleep efficiency, total sleep time, and sleep maintenance were increased and sleep period change index, number of awakenings, wake after sleep onset, and body movements were reduced on the first and second postoperative nights; Pittsburgh Sleep Quality Index scores and occurrence of postoperative sleep disturbance were lower on the first and second nights postoperatively; IL-6 was reduced on the first night postoperatively; IL-1 and IL-10 were reduced on the third night postoperatively; melatonin was increased on the first night postoperatively; and mean arterial pressure and heart rate were decreased before general anesthesia induction, immediately after tracheal intubation, and at the end of the operation (all P < .05). Conclusions: Stellate ganglion block alleviates postoperative sleep disturbance by reducing postoperative inflammatory response, increasing melatonin levels, and stabilizing perioperative hemodynamics in patients undergoing radical surgery for gastrointestinal malignancies. CLINICAL TRIAL REGISTRATION: Registry: ClinicalTrials.gov; Name: The Effect of Stellate Ganglion Block on Postoperative Sleep Disturbance and Cognitive Function in Elderly Surgical Patients; URL: https://clinicaltrials.gov/ct2/show/NCT04800653; Identifier: NCT04800653. CITATION: Yan S, Wang Y, Yu L, et al. Stellate ganglion block alleviates postoperative sleep disturbance in patients undergoing radical surgery for gastrointestinal malignancies. J Clin Sleep Med. 2023;19(9):1633-1642.

Evaluation of tunnel retro-reflective arch in an extra-long tunnel based on the matter-element extension method.

Traffic safety devices are one of the most important tools used to improve safety in tunnels. The tunnel retro-reflective arch (TA) plays a crucial role in stimulating drivers, relieving visual stress, and improving safety. However, determining the TA spacing mostly relies on experience and relevant standards are lacking. The aim of this research was to evaluate the degree of influence of the TA on driver behavior, visual aspects, and psychology in different zones (overall tunnel, curved segment, and middle segment) of extra-long tunnels. To test the influence of TAs, four scenarios were constructed, including three alternatives with different TA spacings (200, 300, and 400 m), and one no-arch design as a control alternative. Based on a driving simulator, the evaluation indicators related to driving safety, smoothness, and handling stability were selected and analyzed. We acquired data every 50 m as an analytical unit. The results show that the TA significantly affects driver behavior, visual aspects, and psychology. According to the matter-element model result, setting the TA spacing to 300 m in curved segment and in the tunnel overall is the best option. In the middle segment, the setting spacing of 400 m is ideal.

Spatial relationships between alcohol outlet densities and drunk driving crashes: An empirical study of Tianjin in China.

INTRODUCTION: Numerous studies have demonstrated the close relationship between alcohol availability and alcohol-related crashes. However, there is still a lack of spatial empirical analysis regarding this relationship, particularly in large cities of developing countries. Differences in alcohol outlets and drinking patterns in these cities may lead to quite different patterns of crash outcomes. METHOD: 3356 alcohol-related crashes were collected from the blood-alcohol test report of a forensic institution in Tianjin, China. Density of alcohol outlets such as retail locations, entertainment venues, restaurants, hotels, and companies were extracted based on 2114 Traffic Analysis Zones (TAZ) together with the residential and demographic characteristics. After applying the exploratory spatial data analysis, this research developed and compared the traditional Ordinary Least Square model (OLS), Spatial Lag Model (SLM), Spatial Error Model (SEM) and Spatial Durbin Model (SDM) to explore spatial effects of all the variables. RESULTS: The results of incremental spatial autocorrelation show that the most significant distance threshold of alcohol-related roadway traffic crashes is 3 km. The SDM is found to be the optimal spatial model to characterize the relationship between alcohol outlets and crashes. The number of alcohol-involved traffic crashes is positively related to population density and retail density, but negatively related to the company density, hotel density, and residential density within the same TAZ. Meanwhile, dense population and hotels have reverse spillover effects in adjacent zones. CONCLUSIONS: The significant spatial direct effect and spillover effect of alcohol outlet densities on drunk driving crashes should not be neglected. These findings could help improve transportation planning, traffic law enforcement and traffic management for large cities in developing countries.

Safety of Raised Pavement Markers in Freeway Tunnels Based on Driving Behavior.

Raised pavement markers (RPMs) are among the common safety features of roads, playing an important role in preventing and reducing traffic crashes. RPMs are regarded as an effective measure for reducing the high crash rate and mortality in freeway tunnels in China. In this study, a driving simulator experiment was conducted to investigate the safety of RPMs in a freeway tunnel. Two different RPM layouts were designed and compared to a control with no RPMs, and 32 drivers participated in the driving simulator experiments. The speed, relative speed difference, lateral position, accelerator power, acceleration, and pupil area were used as indicators of the response characteristics of drivers to RPMs, and the interaction of tunnel length, tunnel zone, and RPM alternatives was discussed. The results indicate that a significant interaction effect exists between tunnel length, tunnel zone, and RPM alternatives. RPMs could help reduce driver anxiety, boredom, and fatigue caused by the dark and monotonous tunnel driving environment, and improve driver alertness and consciousness of speed. Also, the driving risk increases with increasing tunnel length (1800 m to 3500 m).

Dielectric Polarization in Inverse Spinel-Structured Mg2 TiO4 Coating to Suppress Oxygen Evolution of Li-Rich Cathode Materials.

High-energy Li-rich layered cathode materials (≈900 Wh kg-1 ) suffer from severe capacity and voltage decay during cycling, which is associated with layered-to-spinel phase transition and oxygen redox reaction. Current efforts mainly focus on surface modification to suppress this unwanted structural transformation. However, the true challenge probably originates from the continuous oxygen release upon charging. Here, the usage of dielectric polarization in surface coating to suppress the oxygen evolution of Li-rich material is reported, using Mg2 TiO4 as a proof-of-concept material. The creation of a reverse electric field in surface layers effectively restrains the outward migration of bulk oxygen anions. Meanwhile, high oxygen-affinity elements of Mg and Ti well stabilize the surface oxygen of Li-rich material via enhancing the energy barrier for oxygen release reaction, verified by density functional theory simulation. Benefited from these, the modified Li-rich electrode exhibits an impressive cyclability with a high capacity retention of ≈81% even after 700 cycles at 2 C (≈0.5 A g-1 ), far superior to ≈44% of the unmodified counterpart. In addition, Mg2 TiO4 coating greatly mitigates the voltage decay of Li-rich material with the degradation rate reduced by ≈65%. This work proposes new insights into manipulating surface chemistry of electrode materials to control oxygen activity for high-energy-density rechargeable batteries.

Optimal design alternatives of advance guide signs of closely spaced exit ramps on urban expressways.

Advance guide signs for exit ramps along urban expressways are increasingly critical, enhancing safety and mobility by improving the flow of vehicles exiting urban expressways. However, research has devoted scant attention to advance guide signs for exit ramps. This study aimed to identify and propose optimal design alternatives for exit ramp advance guide signs for different types of exit spacing. This study conducted a driving simulation experiment consisting of five design alternatives of advance guide signs and two exit ramp spacing variation. Eight indicators were measured. The repeated-measure analysis of variances (ANOVA) and the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) were performed for the influence analysis and efficiency evaluation of different schemes. Influence analysis results showed better design alternatives in five schemes of advance guide signs, enabling drivers to more easily locate destination exits and change lanes fewer times, in addition to reducing drivers' need to decelerate, and improving traffic flow in the key influence range of destination exit ramps. The percentage of drivers successfully locating the destination exits also increased with optimal design alternatives of advance guide signs. When the exit ramp spacing tightened, on the other hand, drivers had to make more lane changes and accelerate and decelerate more frequently in the key influence range. As a result, a lower percentage of drivers successfully located destination exits. Efficiency evaluation results were also obtained. In tight spacing, three advance guide signs are recommended to be placed at 1 km, 0.5 km and 0 km prior to the beginning of the tapered deceleration lane. If conditions are limited, at least two advance guide signs should be used. With greater spacing, four advance guide signs are recommended, located at 2 km, 1 km, 0.5 km, and 0 km prior to the beginning of the tapered deceleration lane. If road conditions are limited, three advance guide signs should be used.

Effects of connected vehicle-based variable speed limit under different foggy conditions based on simulated driving.

In response to developing and/or diminishing foggy conditions, the variable speed limit application in a connected vehicle environment (CV-VSL) can estimate and deliver recommended travel speeds to individual drivers, which can help to reduce crashes when visibility conditions change. This study aims to quantify the effectiveness of the CV-VSL application by exploring drivers' reactions to warnings (e.g., recommended travel speeds). In order to analyze the effectiveness of the CV-VSL application, a connected vehicle testing platform was established based on a driving simulator, and characteristics of the drivers' speed adjustments after receiving warnings were analyzed with respect to different levels of visibility (i.e., no fog, slight fog, and heavy fog). This study also examined the effect of warnings on drivers in different impact zones (i.e., clear zone, transition zone, and fog zone). Three indicators were identified: 1) speed at the end of the clear zone, 2) maximum deceleration rate in the transition zone, and 3) average speed reduction in the fog zone. Throughout the experiment, the relationship between speed adjustments and the level of visibility was explored. The results indicated that the CV-VSL application is effective in making drivers reduce travel speeds in all three types of zones. Furthermore, it appeared that the CV-VSL application could help manage travel speeds prior to vehicles entering the transition zone, and influence drivers' braking decisions upon encountering reduced visibility. It was also found that the CV-VSL application was more effective in heavy fog conditions than in light fog conditions. The connected vehicle testing platform based on the driving simulator provided a new method for evaluating the effectiveness of in-vehicle messaging generated by connected vehicle applications.

An approach for evaluating the effectiveness of traffic guide signs at intersections.

Traffic guide signs play important roles in people's daily lives. However, the effectiveness and performance of traffic guide signs at intersections are significantly impacted by many factors, such as the types of information on traffic signs, their information volume and comprehensibility, the behavioral attributes of drivers, the geometric features of roadways, and weather and visibility conditions. When deploying traffic guide signs, efforts are needed to clarify whether the installation of a traffic guide sign is warranted. In this study, a generic approach is developed to examine and evaluate the effectiveness of traffic guide signs using simulation experiments. A traffic guide sign evaluation method (TGSEM) is developed and illustrated using examples of traffic guide sign schemes in suburban Beijing. The questionnaires showed that most drivers feel that the current traffic guide signs in suburban Beijing are insufficient and need to be rectified. Then, simulation experiments were conducted. Based on subjective experiments, the ergonomic evaluation model (DCI, the abbreviation of demand, comprehension, and information volume) was obtained. Of the four schemes, scheme 3 was shown to be the most popular. During driving simulation experiments, the analyses of average speed, standard deviation (SD) of speed, average acceleration, standard deviation of acceleration, travel time, braking frequency and throttle power showed that scheme 2 had a better impact on drivers' behavioral data. Finally, Grey relational analysis showed that scheme 2 has the highest degree of correlation and can be recommended to traffic management departments. The experimental tests and analysis results revealed that the TGSEM is suitable. The proposed approach provides a generic framework with which to assess the performance of traffic guide signs and their effectiveness at intersections, including their experimental design, data analysis, the implementation of simulation models, and data interpretation.

Effects of longitudinal speed reduction markings on left-turn direct connectors.

Longitudinal speed reduction markings (LSRMs) are designed to alert drivers to an upcoming change in roadway geometry (e.g. direct connectors with smaller radii). In Beijing, LSRMs are usually installed on direct connectors of urban expressways. The objective of this paper is to examine the influence of LSRMs on vehicle operation and driver behavior, and evaluate the decelerating effectiveness of LSRMs on direct connectors with different radii. Empirical data were collected in a driving simulator, and indicators representing vehicle operation status and driving behavior were proposed. To examine the influence of LSRMs, an analysis segment was defined, which begins 500 m prior to the entering point of the connector and ends at the exiting point of the connector. Furthermore, the analysis segment was evenly divided into a series of subsections; the length of each subsection is 50 m. This definition is introduced based on the assumption that drivers would decelerate smoothly in advance of the connector. The analysis results show that drivers tend to decelerate earlier when the radii were 200 m or 300 m. When approaching the connector, drivers tend to decelerate at 500 m thru 250 m in advance of the connector with a 200 m radius; deceleration happens at 300 m-0 m in advance of the connector with a 300 m radius. On the connector, drivers controlled the throttle pedal use at 100 thru 300 m after the entering point when the radius was 200 m; deceleration occurred in two regions when the radius was 300 m: 0 m-900 m from the entering point, and the last 1,000 m of the connector. The analytical results further revealed that LSRMs would be effective at reducing speeds when the radius of the direct connector was 300 m.

Evaluation Research of the Effects of Longitudinal Speed Reduction Markings on Driving Behavior: A Driving Simulator Study.

The objective of this paper is to explore the effects of longitudinal speed reduction markings (LSRMs) on vehicle maneuvering and drivers' operation performance on interchange connectors with different radii. Empirical data were collected in a driving simulator. Indicators-relative speed change, standard deviation of acceleration, and gas/brake pedal power-were proposed to characterize driving behavior. Statistical results revealed that LSRMs could reduce vehicles' travel speed and limit drivers' willingness to increase speed in the entire connector. To probe the impacts of LSRMs, the connecter was split into four even sections. Effects of LSRMs on driving behavior were stronger in the second and the final sections of connectors. LSRMs also enhanced drivers' adaptability in the first three quarters of a connector when the radius was 50 m. Drivers' gas pedal operation would be impacted by LSRMs in the entire connector when the radius was 50 m. LSRMs could only make drivers press brake pedal more frequently in the second section with 80 m and 100 m radius. In the second quarter section of a connector-from the FQP (the first quartile point) to the MC (the middle point of curve)-LSRMs have better effects on influencing vehicle maneuvering and drivers' operation performance.

Driver injury severity outcome analysis in rural interstate highway crashes: a two-level Bayesian logistic regression interpretation.

There is a high potential of severe injury outcomes in traffic crashes on rural interstate highways due to the significant amount of high speed traffic on these corridors. Hierarchical Bayesian models are capable of incorporating between-crash variance and within-crash correlations into traffic crash data analysis and are increasingly utilized in traffic crash severity analysis. This paper applies a hierarchical Bayesian logistic model to examine the significant factors at crash and vehicle/driver levels and their heterogeneous impacts on driver injury severity in rural interstate highway crashes. Analysis results indicate that the majority of the total variance is induced by the between-crash variance, showing the appropriateness of the utilized hierarchical modeling approach. Three crash-level variables and six vehicle/driver-level variables are found significant in predicting driver injury severities: road curve, maximum vehicle damage in a crash, number of vehicles in a crash, wet road surface, vehicle type, driver age, driver gender, driver seatbelt use and driver alcohol or drug involvement. Among these variables, road curve, functional and disabled vehicle damage in crash, single-vehicle crashes, female drivers, senior drivers, motorcycles and driver alcohol or drug involvement tend to increase the odds of drivers being incapably injured or killed in rural interstate crashes, while wet road surface, male drivers and driver seatbelt use are more likely to decrease the probability of severe driver injuries. The developed methodology and estimation results provide insightful understanding of the internal mechanism of rural interstate crashes and beneficial references for developing effective countermeasures for rural interstate crash prevention.

Evaluation of the effects of school zone signs and markings on speed reduction: a driving simulator study.

Traffic control devices are one of the most significant factors affecting driving behavior. In China, there is a lack of installation guidelines or standards for traffic control devices in school zones. In addition, little research has been done to examine the effects of traffic control devices on driving behavior. Few guidelines have been established for implementing traffic control devices in school zones in China. This research conducted a driving simulator experiment to assess the effects of school zone signs and markings for two different types of schools. The efficiency of these traffic control devices was evaluated using four variables derived from the driving simulation, including average speed, relative speed difference, standard deviation of acceleration, and 85th percentile speed. Results showed that traffic control devices such as the Flashing Beacon and School Crossing Ahead Warning Assembly, the Reduce Speed and School Crossing Warning Assembly, and the School Crossing Ahead Pavement Markings were recommended for school zones adjacent to a major multilane roadway, which is characterized by a median strip, high traffic volume, high-speed traffic and the presence of pedestrian crossing signals. The School Crossing Ahead Pavement Markings were recommended for school zones on a minor two-lane roadway, which is characterized by low traffic volume, low speed, and no pedestrian crossing signals.

Modeling the influence of Chevron alignment sign on young male driver performance: A driving simulator study.

In China, the Chevron alignment sign on highways is a vertical rectangle with a white arrow and border on a blue background, which differs from its counterpart in other countries. Moreover, little research has been devoted to the effectiveness of China's Chevron signs; there is still no practical method to quantitatively describe the impact of Chevron signs on driver performance in roadway curves. In this paper, a driving simulator experiment collected data on the driving performance of 30 young male drivers as they navigated on 29 different horizontal curves under different conditions (presence of Chevron signs, curve radius and curve direction). To address the heterogeneity issue in the data, three models were estimated and tested: a pooled data linear regression model, a fixed effects model, and a random effects model. According to the Hausman Test and Akaike Information Criterion (AIC), the random effects model offers the best fit. The current study explores the relationship between driver performance (i.e., vehicle speed and lane position) and horizontal curves with respect to the horizontal curvature, presence of Chevron signs, and curve direction. This study lays a foundation for developing procedures and guidelines that would allow more uniform and efficient deployment of Chevron signs on China's highways.

From Cellular Attractor Selection to Adaptive Signal Control for Traffic Networks.

The management of varying traffic flows essentially depends on signal controls at intersections. However, design an optimal control that considers the dynamic nature of a traffic network and coordinates all intersections simultaneously in a centralized manner is computationally challenging. Inspired by the stable gene expressions of Escherichia coli in response to environmental changes, we explore the robustness and adaptability performance of signalized intersections by incorporating a biological mechanism in their control policies, specifically, the evolution of each intersection is induced by the dynamics governing an adaptive attractor selection in cells. We employ a mathematical model to capture such biological attractor selection and derive a generic, adaptive and distributed control algorithm which is capable of dynamically adapting signal operations for the entire dynamical traffic network. We show that the proposed scheme based on attractor selection can not only promote the balance of traffic loads on each link of the network but also allows the global network to accommodate dynamical traffic demands. Our work demonstrates the potential of bio-inspired intelligence emerging from cells and provides a deep understanding of adaptive attractor selection-based control formation that is useful to support the designs of adaptive optimization and control in other domains.

A multinomial logit model-Bayesian network hybrid approach for driver injury severity analyses in rear-end crashes.

Rear-end crash is one of the most common types of traffic crashes in the U.S. A good understanding of its characteristics and contributing factors is of practical importance. Previously, both multinomial Logit models and Bayesian network methods have been used in crash modeling and analysis, respectively, although each of them has its own application restrictions and limitations. In this study, a hybrid approach is developed to combine multinomial logit models and Bayesian network methods for comprehensively analyzing driver injury severities in rear-end crashes based on state-wide crash data collected in New Mexico from 2010 to 2011. A multinomial logit model is developed to investigate and identify significant contributing factors for rear-end crash driver injury severities classified into three categories: no injury, injury, and fatality. Then, the identified significant factors are utilized to establish a Bayesian network to explicitly formulate statistical associations between injury severity outcomes and explanatory attributes, including driver behavior, demographic features, vehicle factors, geometric and environmental characteristics, etc. The test results demonstrate that the proposed hybrid approach performs reasonably well. The Bayesian network reference analyses indicate that the factors including truck-involvement, inferior lighting conditions, windy weather conditions, the number of vehicles involved, etc. could significantly increase driver injury severities in rear-end crashes. The developed methodology and estimation results provide insights for developing effective countermeasures to reduce rear-end crash injury severities and improve traffic system safety performance.

Experimental research on safety impacts of the inside shoulder based on driving simulation.

Statistical data shows that single-vehicle crashes account for half of all traffic crashes on expressways in China, and previous research has indicated that main contributing factors were related to whether and how the inside shoulder was paved. The inside shoulder provides space for drivers to make evasive maneuvers and accommodate driver errors. However, lower-cost construction solutions in China have resulted in the design of numerous urban expressway segments that lack inside shoulders. This paper has two objectives. The first is to reveal the safety impacts of inside shoulders on urban expressways by driving simulator experiment. The second objective is to propose optimal range and recommended value of inside shoulder width for designing inside shoulders of urban expressways. The empirical data, including subjects' eye movement data, heart rate (HR) and the lateral position of vehicles, were collected in a driving simulator. The data were analyzed to evaluate the safety impacts of the inside shoulder. The results have revealed that the inside shoulder has an impact on drivers' visual perception, behaviors, and psychology; in particular, it has a significant effect on vehicle operations. In addition, this paper recommends the desired and optimal inside shoulder widths for eight-lane, two-way divided expressways.

Assessment of ozone variations and meteorological influences at a rural site in Northern Xinjiang.

Ozone concentrations and meteorological data were continuously monitored online from June to December 2013 at the Akedala regional atmosphere station in an arid region of Central Asia. We present daily, monthly, and seasonal variations of ozone concentrations in the atmosphere and elucidate possible emission sources. The ozone concentrations of this region varied from 14.7 to 58.6 ppb. A remarkable seasonal variation of ozone in aerosols was observed with highest level in summer, followed by autumn and winter. The daily peak value of ozone was observed at 9:00-11:00 a.m. while the lowest was at 17:00-19:00 p.m. The backward trajectories of air masses showed potential emission sources to be from the northwest and south during the measurement period. The backward trajectory also revealed that ozone concentrations during the measurement period were likely attributable to the emission from anthropogenic activities, and medium-range atmospheric transport from cities in central Asia and the northern slope of the Tian Shan Mountains.