Research on active sound absorption based on minimality of quadratic sum of reflected sound pressure in low frequency

In this paper, the minimality of the quadratic sum of the reflected sound pressure is used to outline the method of active sound absorption. A piezoelectric ceramic is attached to a simply supported plate, and two microphones are placed in the front of the simply supported plate. The reflected sound pressure is measured. According to the measured reflected sound pressure, the voltage is added to the surface of the piezoelectric ceramic. Then, the simply supported plate is vibrated. Thus, the total sound pressure is expressed as a combination of the reflected sound pressure and the radiated sound pressure. A condition of the quadratic sum being minimal is presented and the voltage (added to the surface of the piezoelectric ceramic) is calculated. At last, the numerical calculation and the experiment are carried out, which demonstrate that the method outlined in this paper is possible

Effects of Direct Renin Inhibition on Myocardial Fibrosis and Cardiac Fibroblast Function

Myocardial fibrosis, a major pathophysiologic substrate of heart failure with preserved ejection fraction (HFPEF), is modulated by multiple pathways including the renin-angiotensin system. Direct renin inhibition is a promising anti-fibrotic therapy since it attenuates the pro-fibrotic effects of renin in addition to that of other effectors of the renin-angiotensin cascade. Here we show that the oral renin inhibitor aliskiren has direct effects on collagen metabolism in cardiac fibroblasts and prevented myocardial collagen deposition in a non-hypertrophic mouse model of myocardial fibrosis. Adult mice were fed hyperhomocysteinemia-inducing diet to induce myocardial fibrosis and treated concomitantly with either vehicle or aliskiren for 12 weeks. Blood pressure and plasma angiotensin II levels were normal in control and hyperhomocysteinemic mice and reduced to levels lower than observed in the control group in the groups treated with aliskiren. Homocysteine-induced myocardial matrix gene expression and fibrosis were also prevented by aliskiren. In vitro studies using adult rat cardiac fibroblasts also showed that aliskiren attenuated the pro-fibrotic pattern of matrix gene and protein expression induced by D,L, homocysteine. Both in vivo and in vitro studies demonstrated that the Akt pathway was activated by homocysteine, and that treatment with aliskiren attenuated Akt activation. In conclusion, aliskiren as mono-therapy has potent and direct effects on myocardial matrix turnover and beneficial effects on diastolic function

Lysosomal dysfunction and impaired autophagy underlie the pathogenesis of amyloidogenic light chain-mediated cardiotoxicity

AL amyloidosis is the consequence of clonal production of amyloidogenic immunoglobulin light chain (LC) proteins, often resulting in a rapidly progressive and fatal amyloid cardiomyopathy. Recent work has found that amyloidogenic LC directly initiate a cardio-toxic response underlying the pathogenesis of the cardiomyopathy; however, the mechanisms that contribute to this proteotoxicity remain unknown. Using human amyloidogenic LC isolated from patients with amyloid cardiomyopathy, we reveal that dysregulation of autophagic flux is critical for mediating amyloidogenic LC proteotoxicity. Restoration of autophagic flux by pharmacological intervention using rapamycin protected against amyloidogenic light chain protein-induced pathologies including contractile dysfunction and cell death at the cellular and organ level and also prolonged survival in an in vivo zebrafish model of amyloid cardiotoxicity. Mechanistically, we identify impaired lysosomal function to be the major cause of defective autophagy and amyloidogenic LC-induced proteotoxicity. Collectively, these findings detail the downstream molecular mechanisms underlying AL amyloid cardiomyopathy and highlight potential targeting of autophagy and lysosomal dysfunction in patients with amyloid cardiomyopathy

Decomposition and Nutrient Release of Different Cover Crops in Organic Farm Systems

Cover crops act as green manure adding organic matter to agricultural-soils. For legume green manures to be an effective nitrogen (N) source for organic farming systems, their N release must be in synchrony with crop N demand. The objectives of this study were 1) determine the decomposition rates of three common cover crops (white clover, (Trifolium repens,L ) red clover (Trifolium pratense L.) and soybean (Glycine max L) in order to determine when most N was released and its synchrony with subsequent corn crop uptake; 2) we focused on the effect of cover crops on soil N levels. This study was conducted in a certified organic field, near Mead, NE. We assessed the decomposition rates and chemical composition of three cover crops with different incorporation time (fall and spring). Cover crop samples were taken and air dried in fall and spring. Litterbags containing plant samples were buried at a depth of 15 cm in December, 2011 and March, 2012. The nine extraction times for fall treatment were 0, 12, 16, 20, 24, 28, 32, 40, 48 weeks after burial. For spring treatment, samples were dug up every four weeks. Soil samples from each experimental unit were taken at the same time. Extracted litterbags were oven-dried and samples were analyzed for biomass fractions (soluble, hemicellulose, cellulose, and lignin) and total C and N content. As conclusion, decomposition rates of five treatments follow the order: white clover incorporated in spring\u3e red clover incorporated in spring\u3e white clover incorporated in fall\u3e red clover incorporated in fall\u3e soybean incorporated in fall. Mass loss, nutrient content, and litter quality were all changed mostly in the first 0-3 months, which indicates that early stage of cover crops incorporation is critical to cover crop management. To describe the decomposition process, asymptotic models are more appropriate. Cover crops killed in spring have a better synchrony with corn uptake curve. After growing season, soil following red clover had greater level of soil nitrate-N. Advisor: James R. Brandl

The impact of high-quality development on ecological footprint: An empirical research based on STIRPAT model

It is urgent to coordinate the development of economy and environment under the “dual carbon” goal. As China's new development stage and mode, high-quality development takes into account both the speed and quality of economic, providing the possibility of achieving a “win-win” situation for the economy and the environment. In order to test the practical impact of high-quality development on ecological, based on the STIRPAT model, this paper introduces high-quality development index instead of per capita GDP, so as to measure the current economic situation in China, and explore the relationship between high-quality development and ecological footprint, and demonstrates the feasibility from theory and practice. At the same time, it pays attention to the complex effects of population and technology on environmental quality. The results show that the contradiction between economy and ecology still exists in China. The ecological footprint index of 30 provinces in the past 21 years has increased as a whole, and the fworst ecological footprint has concentrated in the Yellow River basin. But since 2012, the growth of the footprint has slowed. The slow down time and low value region of ecological footprint were observed, and it was found that they overlapped with the proposed time and the high value area of high-quality development. The level of high-quality development in China has also continued to rise, with regional differences but gradually narrowing. Among them, green development and shared development contribute more to the improvement of high-quality development level. Compared with the traditional economic development mode, high-quality development can reduce the increase of ecological footprint, and the longer the time, the smaller the increase, more conducive to long-term sustainable development. In addition, population and technology factors are also profoundly affecting China's ecological pattern. The increase in population size and population density, as well as the increase in the proportion of coal-based energy consumption structure, will lead to increased environmental pressure. The improvement of population quality and the reduction of energy consumption intensity will help alleviate ecological pressure. The research is helpful to provide policy guidance and path combination reference for China's sustainable development, and also provide new ideas for the global coordination of the relationship between economy and environment

How socioeconomic factors affect ecosystem service value: Evidence from China

The impact of social and economic development on local ecological patterns should not be ignored. Because human beings cannot change the natural environment quickly, it is only by paying attention to the research on social and economic factors that we can promote the implementation of policies. From the perspective of ecological economics, this paper selects panel data for 31 provinces in China during 2000–2020 to explore the differences in influencing factors in different socioeconomic development stages by using the spatial Durbin model and piecewise regression method. We found that the distribution of ecosystem service value per unit area in China is uneven, being high in the east and low in the west, high in the south, and low in the north. At different stages of social and economic development, per capita GDP, the proportion of the primary industry, the proportion of the tertiary industry, industrial pollution control investment, population density, construction land area, total investment in key forestry projects, education infrastructure and per capita road length have different impacts on ecosystem service value, and even different spatial spillover effects on local and adjacent areas. Therefore, when formulating policies to improve the value of ecosystem services, the impact of socioeconomic factors in different regions and at different times must be carefully considered