Dynamic modeling and optimal control of a positive buoyancy diving autonomous vehicle

The positive buoyancy diving autonomous vehicle combines the features of an Unmanned Surface Vessel (USV) and an Autonomous Underwater Vehicle (AUV) for marine measurement and monitoring. It can also be used to study reasonable and efficient positive buoyancy diving techniques for underwater robots. In order to study the optimization of low power consumption and high efficiency cruise motion of the positive buoyancy diving vehicle, its dynamic modeling has been established. The optimal cruising speed for low energy consumption of the positive buoyancy diving vehicle is determined by numerical simulation. The Linear Quadratic Regulator (LQR) controller is designed to optimize the dynamic error and the actuator energy consumption of the vehicle in order to achieve the optimal fixed depth tracking control of the positive buoyancy diving vehicle. The results demonstrate that the LQR controller has better performance than PID, and the system adjustment time of the LQR controller is reduced by approximately 56% relative to PID. The motion optimization control method proposed can improve the endurance of the positive buoyancy diving vehicle, and has a certain application value

Obesity-dependent changes in interstitial ECM mechanics promote breast tumorigenesis.

Obesity and extracellular matrix (ECM) density are considered independent risk and prognostic factors for breast cancer. Whether they are functionally linked is uncertain. We investigated the hypothesis that obesity enhances local myofibroblast content in mammary adipose tissue and that these stromal changes increase malignant potential by enhancing interstitial ECM stiffness. Indeed, mammary fat of both diet- and genetically induced mouse models of obesity were enriched for myofibroblasts and stiffness-promoting ECM components. These differences were related to varied adipose stromal cell (ASC) characteristics because ASCs isolated from obese mice contained more myofibroblasts and deposited denser and stiffer ECMs relative to ASCs from lean control mice. Accordingly, decellularized matrices from obese ASCs stimulated mechanosignaling and thereby the malignant potential of breast cancer cells. Finally, the clinical relevance and translational potential of our findings were supported by analysis of patient specimens and the observation that caloric restriction in a mouse model reduces myofibroblast content in mammary fat. Collectively, these findings suggest that obesity-induced interstitial fibrosis promotes breast tumorigenesis by altering mammary ECM mechanics with important potential implications for anticancer therapies

Obesity-dependent changes in interstitial ECM mechanics promote breast tumorigenesis

Obesity and extracellular matrix (ECM) density are considered independent risk and prognostic factors for breast cancer. Whether they are functionally linked is uncertain. We investigated the hypothesis that obesity enhances local myofibroblast content in mammary adipose tissue and that these stromal changes increase malignant potential by enhancing interstitial ECM stiffness. Indeed, mammary fat of both diet- and genetically induced mouse models of obesity were enriched for myofibroblasts and stiffness-promoting ECM components. These differences were related to varied adipose stromal cell (ASC) characteristics because ASCs isolated from obese mice contained more myofibroblasts and deposited denser and stiffer ECMs relative to ASCs from lean control mice. Accordingly, decellularized matrices from obese ASCs stimulated mechanosignaling and thereby the malignant potential of breast cancer cells. Finally, the clinical relevance and translational potential of our findings were supported by analysis of patient specimens and the observation that caloric restriction in a mouse model reduces myofibroblast content in mammary fat. Collectively, these findings suggest that obesity-induced interstitial fibrosis promotes breast tumorigenesis by altering mammary ECM mechanics with important potential implications for anticancer therapies

Hospitality-based critical incidents: a cross-cultural comparison

Purpose - The purpose of this paper is to provide a cross-cultural comparison of Chinese and American hospitality customers who report critical incidents and the resulting influences that these incidents and recovery efforts had on behavior. Recognizing that hospitality-based organizations are increasingly operating internationally, the study provides insights for managing customer relationships. Design/methodology/approach - The study utilizes the critical incident technique in conjunction with a structured self-administered questionnaire. The sampling approach resulted in 1,146 usable responses. Findings - The results demonstrate statistically significant cultural differences between American and Chinese consumers in terms of reported critical incident types, recovery approaches, and post-incident private voice, public voice, and repurchase intention. Research limitations/implications - This research uses cultural value scores for China and the USA as a way to explain and discuss the findings. Hofstede's model was not tested and the provided explanations should be viewed with caution. Practical implications - The results of this research can provide practitioners with guidelines in regards to service recovery tactics, as well as insights into how customers respond to critical incidents across different cultures. Originality/value - This study adds to the existing literature by investigating empirically critical incident types, recovery tactics, and the consumer post-encounter behaviors of public voice (i.e. complaining), private voice (i.e. negative word-of-mouth, positive word-of-mouth), and repurchase intention in China and the USA

Nanopillar Arrayed Triboelectric Nanogenerator as a Self-Powered Sensitive Sensor for a Sleep Monitoring System

A flexible and low-cost triboelectric nanogenerator (TENG) based on a patterned aluminum–plastic film and an entrapped cantilever spring leaf is developed as a self-powered sensitive triboelectric sensor for sleep–body movement monitoring. The working mechanism and the impact factors of electric output performance were systematically investigated and elaborated. Due to the patterned nanostructures of the recently designed TENG, both the output voltage and current are greatly enhanced, and thereby the sensitivity of the device is significantly improved. The self-powered and sensitive device has been demonstrated as a smart body motion sensor of sleep monitoring for diagnosis of sleep disorders due to its high sensitivity and excellent stability. This work may promote the application of self-powered TENGs for healthcare and be helpful for the development of real-time mobile healthcare services and smart external portable electronics