Assessment of left ventricular energy loss in patients with mild coronary artery stenosis by using vector flow mapping combined with exercise stress echocardiography.

OBJECTIVES: To evaluate the left ventricular energy loss (EL), energy loss reserve (EL-r), and energy loss reserve rate in patients with mild coronary artery stenosis by using vector flow mapping (VFM) combined with exercise stress echocardiography. METHODS: A total of 34 patients (case group) with mild coronary artery stenosis and 36 sex and age matched patients (control group) without coronary artery stenosis according to coronary angiogram were prospectively enrolled. The total energy loss (ELt), basal segment energy loss (ELb), middle segment energy loss (ELm), apical segment energy loss (ELa), energy loss reserve (EL-r), and energy loss reserve rate were recorded in the isovolumic systolic period (S1), rapid ejection period (S2), slow ejection period (S3), isovolumic diastolic period (D1), rapid filling period (D2), slow filling period (D3), and atrial contraction period (D4). RESULTS: Compared with the control group, some of the EL in the resting case group were higher; some of the EL in the case group were lower after exercise, and those during D1 ELb and D3 ELb were higher. Compared with the resting state, the total EL and the EL within the time segment in the control group were higher after exercise, except during D2 ELb. In the case group, except for during D1 ELt, ELb and D2 ELb, the total and segmental EL of each phase was mostly higher after exercise (p < .05). Compared with the control group, most of the EL-r and EL reserve rates in the case group were lower (p < .05). CONCLUSION: The EL, EL-r, and energy loss reserve rate have a certain value in the evaluation of cardiac function in patients with mild coronary artery stenosis.

Low-cost composite film triboelectric nanogenerators for a self-powered touch sensor.

In the last two decades, nanogenerators have been studied inorder to solve the power supply problems of electronic devices. Triboelectric nanogenerators (TENGs) have gained widespread attention due to their excellent properties and wide range of applications. However, previous studies frequently ignored numerous application-related issues and even wasted some of the benefits of the TENG itself in favor of enhanced performance. Here, we propose a TENG based on BaTiO3 (BTO)-polydimethylsiloxane (PDMS) composite films with low cost and simple preparation, where its maximum output performance is obtained when the mass proportion of BTO to PDMS is 40%. In addition, we demonstrate how the single-electrode TENG may be used as a self-powered touch sensor that can communicate with a microcontroller unit (MCU) to turn LED lights on and off. This practical example will provide a valuable reference for the application of low-cost self-powered sensors in wearable devices, Internet of Things, human-machine interactions and other fields. Furthermore, we discovered a number of issues that were rarely or never addressed in previous studies and provide some solutions, such as a signal processing method for a TENG-based self-powered sensor. It serves as a foundation for future investigations on the performance assessment and application of TENGs.

Effects of aircraft tray table height and neck posture on passenger comfort: A study of the economy class cabin.

BACKGROUND: The tray table in economy class air travel may cause excessive neck flexion and discomfort in passengers. OBJECTIVE: The purpose of this study is to examine the influence of different tray table heights on the neck posture and discomfort perception of passengers. METHODS: A passenger experience survey was used to determine the passengers' view that the tray table was not high enough, and that most passengers were dissatisfied with the overall comfort evaluation of the tray table, especially passengers with obesity. Three head-neck angles and discomfort perceptions of six body parts in 58 participants were recorded by neck posture 3D scanning and perceived level of discomfort assessment, respectively. RESULTS: Tray tables at the original height (68 cm) caused unnatural neck posture and discomfort in participants. Raising the tray table can improve the neck posture of participants and reduce discomfort. However, raising the tray table too high will cause more shoulder discomfort in participants. Based on the results, 78 (±2) cm is suggested as the suitable thresholds range of tray tables for economy class air travel. CONCLUSION: The results and findings of this study could provide a theoretical base for the optimization of tray table design.

MRI-Based Radiomics Analysis for Intraoperative Risk Assessment in Gravid Patients at High Risk with Placenta Accreta Spectrum.

BACKGROUND: Gravid patients at high risk with placenta accreta spectrum (PAS) face life-threatening risk at delivery. Intraoperative risk assessment for patients is currently insufficient. We aimed to develop an assessment system of intraoperative risks through MRI-based radiomics. METHODS: A total of 131 patients enrolled were randomly grouped according to a ratio of 7:3. Clinical data were analyzed retrospectively. Radiomic features were extracted from sagittal Fast Imaging Employing State-sate Acquisition images. Univariate and multivariate regression analyses were performed to build models using R software. A receiver operating characteristic curve and decision curve analysis (DCA) were performed to determine the predictive performance of models. RESULTS: Six radiomic features and two clinical variables were used to construct the combined model for selection of removal protocols of the placenta, with an area under the curve (AUC) of 0.90 and 0.91 in the training and test cohorts, respectively. Nine radiomic features and two clinical variables were obtained to establish the combined model for prediction of intraoperative blood loss, with an AUC of 0.90 and 0.88 in the both cohorts, respectively. The DCA confirmed the clinical utility of the combined model. CONCLUSION: The analysis of combined MRI-based radiomics with clinics could be clinically beneficial for patients.

Exploring the optimal reverse supply chain for e-waste treatment under Chinese government subsidy.

This study aims to analyze the influence of Chinese government subsidy on e-waste treatment formal and informal reverse supply chains (RSC) and to explore the optimal formal channel structure. Under the formal recycler-Stackelberg game, we establish three game theory models respectively under the conditions of price insensitive and price sensitive overall collection quantity. In each model, a dual-channel RSC, the green technology investment decision of formal recycler and a subsidy for formal recycler are modelled. Besides, the three models are different in collectors and collection effort implementers of the formal channel. Through mathematical modelling and comparison analysis, the study concludes that the best choice for the formal recycling enterprises is to establish its own collection channel or centralize other independent collection channels. Under the condition of price insensitive overall collection quantity, the suboptimal choice is to implement collection effort positively. Under the condition of price sensitive overall collection quantity, the suboptimal choice is to outsource the collection effort when formal recycling enterprises benefit more from the collection effort. And the phenomenon is more outstanding when the overall collection quantity can be greatly improved by the collection price. For governments, they are recommended to prudently implement the subsidy and determine the amount of subsidy because the subsidy may benefit informal channels and the effectiveness of the subsidy varies along with formal channel structures. This study is beneficial for the promotion of formal RSC by providing the optimal channel structure for formal recycling enterprises and indicating the optimal subsidy for governments.

Feasibility study of the unit pricing system for household wastes sorting in the context of China.

Although sanitary household waste disposal was achieved in China, an efficient source separation system has not been built yet. The Unit Pricing System has been proved effective for household waste sorting by developed countries and regions, while rare developing countries have successfully introduced the system in their local context. The study, taking an interactive perspective of dominant factors of residents' waste sorting and governments' intervention, combines theoretical analysis with system simulation to dissect the evolution process of residents' waste sorting and local governments' Unit Pricing System policy making, and to provide a Unit Pricing System policy making tool to support policy implementations. The results suggest introducing a Unit Pricing System can significantly push ahead the household waste sorting behaviour for cities with relatively low initial status of environmental awareness, and immediately trigger sorting behaviours for cities with higher initial status of environmental awareness. The study can also benefit other developing countries when imposing waste sorting management instruments.

[Measuring water ecological carrying capacity with the ecosystem-service-based ecological footprint (ESEF) method: Theory, models and application].

Integrated watershed management based on aquatic ecosystems has been increasingly acknowledged. Such a change in the philosophy of water environment management requires recognizing the carrying capacity of aquatic ecosystems for human society from a more general perspective. The concept of the water ecological carrying capacity is therefore put forward, which considers both water resources and water environment, connects socio-economic development to aquatic ecosystems and provides strong support for integrated watershed management. In this paper, the authors proposed an ESEF-based measure of water ecological carrying capacity and constructed ESEF-based models of water ecological footprint and capacity, aiming to evaluate water ecological carrying capacity with footprint methods. A regional model of Taihu Lake Basin was constructed and applied to evaluate the water ecological carrying capacity in Changzhou City which located in the upper reaches of the basin. Results showed that human demand for water ecosystem services in this city had exceeded the supply capacity of local aquatic ecosystems and the significant gap between demand and supply had jeopardized the sustainability of local aquatic ecosystems. Considering aqua-product provision, water supply and pollutant absorption in an integrated way, the scale of population and economy aquatic ecosystems in Changzhou could bear only 54% of the current status.

Assessment of myocardial viability in patients with acute myocardial infarction by two-dimensional speckle tracking echocardiography combined with low-dose dobutamine stress echocardiography.

It is clinically important to determine the myocardial viability of regional wall motion abnormality segments in patients with acute myocardial infarction (AMI). The purpose of this study was to ascertain the ability and value of a combination of speckle tracking echocardiography (STE) and low dose dobutamine stress echocardiography (LDDSE) for the evaluation of viable myocardium in patients with AMI. Forty-two hospitalized patients with AMI and left ventricular systolic dysfunction (left ventricular ejection fraction <50%) were underwent STE in conjunction with LDDSE and dual isotope simultaneous acquisition single photon emission computed tomography (DISA-SPECT). Percutaneous coronary intervention (PCI) was performed subsequently in all patients. STE was used to measure radial, circumferential, and longitudinal end-systolic strain and peak systolic strain rate. The movement of each segment was observed by routine echocardiography 1, 3, and 6 months after PCI, and its improvement over time was the criterion of viable myocardium. The sensitivity, specificity and accuracy of DISA-SPECT for the assessment of viable myocardium were 83.6, 74.4, and 80.7%, respectively. Among the radial, circumferential, and longitudinal strain and strain rate parameters, only longitudinal strain (LS) and longitudinal strain rate (LSr) at rest and LDDSE emerged as independent predictors of viable myocardium, When combining LS and LSr at LDDSE, the sensitivity, specificity and accuracy for the assessment of viable myocardium rose to 89.8, 90.2 and 89.9%, respectively. The sensitivity of STE in conjunction with LDDSE was similar to DISA-SPECT for detecting viable myocardium in patients with AMI, but the specificity and accuracy of STE performed with LDDSE were higher than DISA-SPECT.