A Linear-Power-Regulated Wireless Power Transfer Method for Decreasing the Heat Dissipation of Fully Implantable Microsystems.

Magnetic coupling resonance wireless power transfer can efficiently provide energy to intracranial implants under safety constraints, and is the main way to power fully implantable brain-computer interface systems. However, the existing maximum efficiency tracking wireless power transfer system is aimed at optimizing the overall system efficiency, but the efficiency of the secondary side is not optimized. Moreover, the parameters of the transmitter and the receiver change nonlinearly in the power control process, and the efficiency tracking mainly depends on wireless communication. The heat dissipation caused by the unoptimized receiver efficiency and the wireless communication delay in power control will inevitably affect neural activity and even cause damage, thus affecting the results of neuroscience research. Here, a linear-power-regulated wireless power transfer method is proposed to realize the linear change of the received power regulation and optimize the receiver efficiency, and a miniaturized linear-power-regulated wireless power transfer system is developed. With the received power control, the efficiency of the receiver is increased to more than 80%, which can significantly reduce the heating of fully implantable microsystems. The linear change of the received power regulation makes the reflected impedance in the transmitter change linearly, which will help to reduce the dependence on wireless communication and improve biological safety in received power control applications.

Insights on tiger nut (Cyperus Esculentus L.) oil-loaded microcapsules: characterization and oxidation stability analysis.

In this paper, tiger nut oil-loaded microcapsules (TNOMs) were prepared by complexation soybean protein isolate (SPI) and maltodextrin (MD) as wall materials using the spray drying method with tiger nut oil (TNO) as the core material, and its physicochemical properties and stabilities were characterized and analyzed. Under the optimum conditions, the encapsulation efficiency (EE) of TNOMs could reach up to 91.23%. Of note, after 60 days of storage at 60 °C, the peroxide value (PV) of TNO was almost 21.8 times as much as that of TNO encapsulated. Furthermore, TNOMs had good thermal stability below 200 °C and are sufficient for the general food processing needs. By fitting Arrhenius oxidation kinetics model, it was predicted that the shelf life of the product stored at 25 °C was 352.48 d. Therefore, it is promised to be applied to the development of high oleic acid food in the future. This study offered a theoretical framework for utilization and broadening the range of applications of TNO in the food industry.

Changes in the Surface Water Nitrogen Content in the Upper Hun River Basin, Northeast China.

Human activities have considerably increased nitrogen intake into waterways, resulting in the deterioration of water quality. The state of surface water requires special consideration in light of the water crisis caused by nitrogen pollution. In this study, the natural abundance of the nitrogen stable isotope (δ 15N) is measured and sampled in sediments and compared with the total dissolved nitrogen (DN) in four main Chinese tributaries of Hun River upper reach, including the Dasuhe, Beisanjia, Beikouqian, and Nanzamu tributaries. Results show that for the Dasuhe and Nankouqian tributaries, the δ 15N values of sediment samples in 2016 are all significantly higher than previous values in 2011. In the Dasuhe tributary, this change is attributed to the promotion of organic agricultural production under which chemical fertilizers are replaced by organic fertilizers. For the δ 15N values of the sediment in the Nankouqian tributary, the construction of the municipal sewer system and wastewater treatment facilities are the causes of this rising trend. The δ 15N values of nitrate released by facilities could be raised by microbial denitrification that is employed in the tertiary treatment process. Most of the δ 15N values of the sediments are distributed between soil and manure, indicating that nitrogen in the river water mainly comes from agriculture. All the surveyed tributaries except Dasuhe show a significant increase in DN. In addition, a significant positive correlation between the change ratio of the farmland area and DN in river water is observed, suggesting that the increase in nitrogen in river water from 2011 to 2016 is due to agriculture. Based on the abovementioned data, this study provides a basis for local governments to formulate management measures.