Novel developments in the study of estrogen in the pathogenesis and therapeutic intervention of lymphangioleiomyomatosis.

OBJECTIVE: This study aimed to enhance the understanding of the role of estrogen in lymphangioleiomyomatosis(LAM) and to conclude the impact of estrogen-altering events on the condition and recent advances in estrogen-based treatments for LAM. RESULTS: LAM development is strongly linked to mutations in the tuberous sclerosis gene (TSC1/2) and the presence of estrogen. Estrogen plays a significant role in the spread of TSC2-deficient uterine leiomyoma cells to the lungs and the production of pulmonary LAM. Menstruation, pregnancy, estrogen medication, and other events that cause an increase in estrogen levels can trigger the disorder, leading to a sudden worsening of symptoms. Current findings do not support using estrogen-blocking therapy regimens. However, Faslodex, which is an estrogen receptor antagonist, presents new possibilities for future therapeutic approaches in LAM. CONCLUSION: Estrogen is crucial in the development and spread of LAM. The use of estrogen inhibitors or estrogen receptor antagonists alone does not provide good control of the disease or even poses a greater risk, and the use of a combination of mTOR receptor inhibitors, complete estrogen receptor antagonists, estrogen inhibitors, and autophagy inhibitors targeting important signaling pathways in LAM pathogenesis may be of greater benefit to the patient.

Quantitative Analysis on Risk Influencing Factors in the Jiangsu Segment of the Yangtze River.

Quantitative risk influencing factors (RIFs) are proposed, using the Conjugate Bayesian update approach to analyze 945 collision accidents and incidents cases from the Jiangsu Segment of the Yangtze River over five years from 2012 to 2016. The accident probability is compared under a pairwise comparison mode in order to reflect the relative risk between accidental situations. The Bayesian update mode is constructed to quantitatively evaluate the relative importance of different RIFs. The riskiest segment of Jiangsu Waterways as well the main causations of collisions are identified based on the distributions of collision risk in the six segments of the waterways. The results can support managers to develop the most effective policies to mitigate the collision risk.

The Role of the Prefrontal Cortex and Functional Connectivity during Maritime Operations: An fNIRS study.

INTRODUCTION: Watchkeeping is a significant activity during maritime operations, and failures of sustained attention and decision-making can increase the likelihood of a collision. METHODS: A study was conducted in a ship bridge simulator where 40 participants (20 experienced/20 inexperienced) performed: (1) a 20-min period of sustained attention to locate a target vessel and (2) a 10-min period of decision-making/action selection to perform an evasive maneuver. Half of the participants also performed an additional task of verbally reporting the position of their vessel. Activation of the prefrontal cortex (PFC) was captured via a 15-channel functional near-infrared spectroscopy (fNIRS) montage, and measures of functional connectivity were calculated frontal using graph-theoretic measures. RESULTS: Neurovascular activation of right lateral area of the PFC decreased during sustained attention and increased during decision-making. The graph-theoretic analysis revealed that density declined during decision-making in comparison with the previous period of sustained attention, while local clustering declined during sustained attention and increased when participants prepared their evasive maneuver. A regression analysis revealed an association between network measures and behavioral outcomes, with respect to spotting the target vessel and making an evasive maneuver. CONCLUSIONS: The right lateral area of the PFC is sensitive to watchkeeping and decision-making during operational performance. Graph-theoretic measures allow us to quantify patterns of functional connectivity and were predictive of safety-critical performance.

Ultrasonic measurement of lubricant film thickness distribution of journal bearing.

Most film thickness measurement methods damage the working surface of a bearing and cannot measure the minimum film thickness, making it difficult to reveal the lubrication state and warn of wear. Two non-intrusive ultrasonic methods were proposed for measuring the film thickness distribution of the bearing, i.e., the full circumferential measurement and the prediction based on limited measuring points. The ultrasonic recognition model of film thickness was built. A film thickness measuring device and its calibration device were constructed. A calibration experiment in the range of 1-150 µm and a measurement experiment of the bearing's film thickness distribution were carried out. The results showed that in the calibration range, the relative error of most recognition values was less than ±5%, and some are less than 3%. The identification accuracy of the spring model has a zoned phenomenon. The relative difference between the experimental and the simulated values of the film thickness was less than 8% under most working conditions. The predicted values of eccentricity, attitude angle, and minimum film thickness have a small difference from the simulated values, indicating that the accuracy of the measurement method is high.

Multi-objective path planning for unmanned surface vehicle with currents effects.

This paper investigates the path planning problem for unmanned surface vehicle (USV), wherein the goal is to find the shortest, smoothest, most economical and safest path in the presence of obstacles and currents, which is subject to the collision avoidance, motion boundaries and velocity constraints. We formulate this problem as a multi-objective nonlinear optimization problem with generous constraints. Then, we propose the dynamic augmented multi-objective particle swarm optimization algorithm to achieve the solution. With our approach, USV can select the ideal path from the Pareto optimal paths set. Numerical simulations verify the effectiveness of our formulated model and proposed algorithm.

Optimized maritime emergency resource allocation under dynamic demand.

Emergency resource is important for people evacuation and property rescue when accident occurs. The relief efforts could be promoted by a reasonable emergency resource allocation schedule in advance. As the marine environment is complicated and changeful, the place, type, severity of maritime accident is uncertain and stochastic, bringing about dynamic demand of emergency resource. Considering dynamic demand, how to make a reasonable emergency resource allocation schedule is challenging. The key problem is to determine the optimal stock of emergency resource for supplier centers to improve relief efforts. This paper studies the dynamic demand, and which is defined as a set. Then a maritime emergency resource allocation model with uncertain data is presented. Afterwards, a robust approach is developed and used to make sure that the resource allocation schedule performs well with dynamic demand. Finally, a case study shows that the proposed methodology is feasible in maritime emergency resource allocation. The findings could help emergency manager to schedule the emergency resource allocation more flexibly in terms of dynamic demand.

Coupling mechanism between wear and oxidation processes of 304 stainless steel in hydrogen peroxide environments.

Stainless steel is widely used in strongly oxidizing hydrogen peroxide (H2O2) environments. It is crucial to study its wear behaviour and failure mode. The tribological properties and oxidation of 304 stainless steel were investigated using a MMW-1 tribo-tester with a three-electrode setup in H2O2 solutions with different concentrations. Corrosion current densities (CCDs), coefficients of frictions (COFs), wear mass losses, wear surface topographies, and metal oxide films were analysed and compared. The results show that the wear process and oxidation process interacted significantly with each other. Increasing the concentration of H2O2 or the oxidation time was useful to form a layer of integrated, homogeneous, compact and thick metal oxide film. The dense metal oxide films with higher mechanical strengths improved the wear process and also reduced the oxidation reaction. The wear process removed the metal oxide films to increase the oxidation reaction. Theoretical data is provided for the rational design and application of friction pairs in oxidation corrosion conditions.

Three-Stage Decision-Making Model under Restricted Conditions for Emergency Response to Ships Not under Control.

A ship that is not under control (NUC) is a typical incident that poses serious problems when in confined waters close to shore. The emergency response to NUC ships is to select the best risk control options, which is a challenge in restricted conditions (e.g., time limitation, resource constraint, and information asymmetry), particularly in inland waterway transportation. To enable a quick and effective response, this article develops a three-stage decision-making framework for NUC ship handling. The core of this method is (1) to propose feasible options for each involved entity (e.g., maritime safety administration, NUC ship, and ships passing by) under resource constraint in the first stage, (2) to select the most feasible options by comparing the similarity of the new case and existing cases in the second stage, and (3) to make decisions considering the cooperation between the involved organizations by using a developed Bayesian network in the third stage. Consequently, this work provides a useful tool to achieve well-organized management of NUC ships.

An Evidential Reasoning-Based CREAM to Human Reliability Analysis in Maritime Accident Process.

This article proposes a modified cognitive reliability and error analysis method (CREAM) for estimating the human error probability in the maritime accident process on the basis of an evidential reasoning approach. This modified CREAM is developed to precisely quantify the linguistic variables of the common performance conditions and to overcome the problem of ignoring the uncertainty caused by incomplete information in the existing CREAM models. Moreover, this article views maritime accident development from the sequential perspective, where a scenario- and barrier-based framework is proposed to describe the maritime accident process. This evidential reasoning-based CREAM approach together with the proposed accident development framework are applied to human reliability analysis of a ship capsizing accident. It will facilitate subjective human reliability analysis in different engineering systems where uncertainty exists in practice.

Tribological Properties of Water-lubricated Rubber Materials after Modification by MoS2 Nanoparticles.

Frictional vibration and noise caused by water-lubricated rubber stern tube bearings, which are generated under extreme conditions, severely threaten underwater vehicles' survivability and concealment performance. This study investigates the effect of flaky and spherical MoS2 nanoparticles on tribological properties and damping capacity of water-lubricated rubber materials, with the aim of decreasing frictional noise. A CBZ-1 tribo-tester was used to conduct the sliding tests between rubber ring-discs and ZCuSn10Zn2 ring-discs with water lubrication. These materials' typical mechanical properties were analysed and compared. Coefficients of friction (COFs), wear rates, and surface morphologies were evaluated. Frictional noise and critical velocities of generating friction vibration were examined to corroborate above analysis. Results showed that spherical MoS2 nanoparticles enhanced rubber material's mechanical and tribological properties and, in turn, reduced the friction noise and critical velocity. Flaky MoS2 nanoparticles reduced COF but did not enhance their mechanical properties, i.e., the damping capacity, wear resistance property; thus, these nanoparticles did not reduce the critical velocity obviously, even though increased the frictional noise at high load. The knowledge gained in the present work will be useful for optimizing friction pairs under extreme conditions to decrease frictional noise of water-lubricated rubber stern tube bearings.

Maritime Transportation Risk Assessment of Tianjin Port with Bayesian Belief Networks.

This article develops a Bayesian belief network model for the prediction of accident consequences in the Tianjin port. The study starts with a statistical analysis of historical accident data of six years from 2008 to 2013. Then a Bayesian belief network is constructed to express the dependencies between the indicator variables and accident consequences. The statistics and expert knowledge are synthesized in the Bayesian belief network model to obtain the probability distribution of the consequences. By a sensitivity analysis, several indicator variables that have influence on the consequences are identified, including navigational area, ship type and time of the day. The results indicate that the consequences are most sensitive to the position where the accidents occurred, followed by time of day and ship length. The results also reflect that the navigational risk of the Tianjin port is at the acceptable level, despite that there is more room of improvement. These results can be used by the Maritime Safety Administration to take effective measures to enhance maritime safety in the Tianjin port.

Delayed administration of recombinant human erythropoietin reduces apoptosis and inflammation and promotes myelin repair and functional recovery following spinal cord compressive injury in rats.

PURPOSE: A previous study showed that a 1-h delay in treatment of thoracic spinal cord injury (SCI) with recombinant human erythropoietin (rhEPO) lacked neuroprotective efficacy. The aim of the present study was to reassess delayed administration of different doses of rhEPO on acute spinal cord compressive injury in rats. METHODS: The experiment was divided into first and second stages, which SCI rats were observed for 4 and 28 days, respectively. All rats were randomly divided into four groups at both stages: control group, and rhEPO-3,000U (Unit), rhEPO-4,000U and rhEPO-5,000U groups. SCI rats received rhEPO treatment at different time points. The primary indicators were locomotor recovery, histopathology, apoptotic index, inflammatory index, ultrastructural scoring system and volume of areas of demyelination. RESULTS: The most significant locomotor functional and histopathological improvements and the best myelin protection were observed after administration of 5,000 U/kg rhEPO. rhEPO at 3,000, 4,000 and 5,000 U/kg showed similar ultrastructural neuroprotection, as well as similar inhibition of apoptosis and regulation of inflammation. CONCLUSION: Delayed administration of rhEPO can reduce apoptosis and inflammation, and promote myelin repair and functional recovery following spinal cord compressive injury in rats.

Effectiveness of maritime safety control in different navigation zones using a spatial sequential DEA model: Yangtze River case.

This paper aims to analyze the effectiveness of maritime safety control from the perspective of safety level along the Yangtze River with special considerations for navigational environments. The influencing variables of maritime safety are reviewed, including ship condition, maritime regulatory system, human reliability and navigational environment. Because the former three variables are generally assumed to be of the same level of safety, this paper focuses on studying the impact of navigational environments on the level of safety in different waterways. An improved data envelopment analysis (DEA) model is proposed by treating the navigational environment factors as inputs and ship accident data as outputs. Moreover, because the traditional DEA model cannot provide an overall ranking of different decision making units (DMUs), the spatial sequential frontiers and grey relational analysis are incorporated into the DEA model to facilitate a refined assessment. Based on the empirical study results, the proposed model is able to solve the problem of information missing in the prior models and evaluate the level of safety with a better accuracy. The results of the proposed DEA model are further compared with an evidential reasoning (ER) method, which has been widely used for level of safety evaluations. A sensitivity analysis is also conducted to better understand the relationship between the variation of navigational environments and level of safety. The sensitivity analysis shows that the level of safety varies in terms of traffic flow. It indicates that appropriate traffic control measures should be adopted for different waterways to improve their safety. This paper presents a practical method of conducting maritime level of safety assessments under dynamic navigational environment.

Common noise induced synchronous circadian oscillations in uncoupled non-identical systems.

The effect of common noise on the collective behavior of circadian oscillation systems was studied in an elementary circadian clock model. It is shown that common noise could induce synchronous oscillations in two uncoupled non-identical systems in the deterministic stable steady state region. The synchronicity of common noise induced oscillations is suppressed by the internal noise, but is not remarkably decreased within a wide range of internal noise intensity. This demonstrates that the common noise induced synchronous oscillations are rather robust to internal fluctuations.

Motor vehicle-bicycle crashes in Beijing: irregular maneuvers, crash patterns, and injury severity.

This research presents a comprehensive analysis of motor vehicle-bicycle crashes using 4 years of reported crash data (2004-2007) in Beijing. The interrelationship of irregular maneuvers, crash patterns and bicyclist injury severity are investigated by controlling for a variety of risk factors related to bicyclist demographics, roadway geometric design, road environment, etc. Results show that different irregular maneuvers are correlated with a number of risk factors at different roadway locations such as the bicyclist age and gender, weather and traffic condition. Furthermore, angle collisions are the leading pattern of motor vehicle-bicycle crashes, and different irregular maneuvers may lead to some specific crash patterns such as head-on or rear-end crashes. Orthokinetic scrape is more likely to result in running over bicyclists, which may lead to more severe injury. Moreover, bicyclist injury severity level could be elevated by specific crash patterns and risk factors including head-on and angle collisions, occurrence of running over bicyclists, night without streetlight, roads without median/division, higher speed limit, heavy vehicle involvement and older bicyclists. This study suggests installation of median, division between roadway and bikeway, and improvement of illumination on road segments. Reduced speed limit is also recommended at roadway locations with high bicycle traffic volume. Furthermore, it may be necessary to develop safety campaigns aimed at male, teenage and older bicyclists.

[Review and prospect of analysis on UHMWPE wear debris in artificial hip joints].

This paper briefly reviews the latest progress in the analyses of the technologies for artificial hip joints; and in the researches directed to the features of UHMWPE debris obtained from all kinds of experimental conditions, to the wear process and wear mechanism, and to the factors which influence the wear mechanism. Furthermore, the signification of debris atlas was illustrated. Finally, future directions to be furthered were considered and envisaged. It is suggested that emphases be laid on the relationship between the UHMWPE debris feature and the wear mechanism, and be laid synergistic effects of biochemical environment and loading environment so as to establish the predictive wear models of artificial hip joints.

Effects of superior colliculus ablation on the air-righting reflex in the rat.

To examine how the superior colliculus, the motor center of orientation and avoidance, could interact with postural reflexes, we investigated effects of unilateral and bilateral ablations on air-righting reflex movements in otherwise intact rats. Superior colliculus ablations variously modified righting movements: After falling from the supine position, the rats sometimes showed dorsiflexion instead of normal ventriflexion; the motor sequence of rotation from the fore- to the hindquarter was often modified to simultaneous rotation; lateral turn from supine to prone position was occasionally insufficient; body direction that was normally kept constant during falling was often changed; final posture sometimes deviated from the horizontal position. The first three abnormalities occurred almost twice in frequency as lesions increased from unilateral to bilateral ablation, and in unilaterally ablated rats, did so in righting contraversive to the lesions. Multiple influences of tectoreticular input to the air-righting reflex center are discussed.