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This paper proposes a piezoelectric energy harvester that concentrates force on the piezoelectric element by parallel springs. When vibrating, the force exerted by the mass is released at three equal points on the surface of the brass substrate through three parallel springs. This concentrated release of energy through the spring amplification effect facilitates large deformation of the piezoelectric ceramic sheet, resulting in a higher charge output. The results show that under the combined action of a 14 g annular hollow mass and a 0.3 mm wire diameter stainless steel spring, the energy harvester based on the lead zirconate titanate ceramic exhibited an outstanding output power of 1.0–32.1 mW at a low resonance frequency with acceleration amplitudes of 0.5–3 g (1 g = 9.8 m/s2). More importantly, to match the vibration frequency of the actual environment, this paper optimized the structure of the harvester and proposed that the harvester can be designed by selecting the weight of the mass block, the parameters and number of springs, and the shape of the brass substrate. The energy harvester designed in this study is expected to capture energy from low-frequency natural environments and exhibit outstanding output performance, which can provide guidelines for future efforts in this direction. [ABSTRACT FROM AUTHOR]

Real-time health monitoring and precision treatment are important in the biomedical field. Researchers have focused on unique gadgets with peculiar functions, which have emerged from the merging of electronic components with biological systems. Because implantable bioelectronics can sense bodily information or elicit bodily reactions in living creatures from sites outside the body, they are becoming helpful and promising remedies for a variety of ailments. Carbon materials are more suitable than other materials for the manufacture of implantable medical electronics due to their excellent biocompatibility, fatigue resistance, and low specific gravity. Therefore, carbon materials can apply to a wide range of implantable drug delivery devices, biosensors, therapeutic stimulators, and energy storage and play irreplaceable roles in neurological, cardiovascular, gastrointestinal, and locomotor systems, among others. This review aims to offer researchers insight into carbon-based implantable bioelectronics in the biomedical field. Initially, various types of carbon materials were introduced. Subsequently, it delves into carbon-based implantable bioelectronics from four perspectives: implantable actuators, biosensors, drug delivery systems, and power supplies. Furthermore, we anticipate the future direction and potential applications of carbon-based implantable bioelectronics. Given the evolving field of nanotechnology and bioelectronics, we are optimistic that these devices will foster significant breakthroughs and innovations in the biomedical sector. Ultimately, this review aims to assist researchers in navigating the choices and directions of carbon-based implantable bioelectronics, thereby promoting the advancement of the biomedical field and contributing positively to the health and welfare of humankind. [ABSTRACT FROM AUTHOR]

Single-phase Mn50Ni40In10−xCux (x = 0, 1, 2, 4, 6, 8, and 10) Heusler alloys were synthesized by melt-spinning method. Martensitic transformation is retained within the whole composition range studied. The substitution of Cu for In leads to a drastic increase in the martensitic transformation temperature TM from below room temperature to above 750 K, and enhances the antiferromagnetic character of the martensite. The increase in TM is related to the increasing electron concentration e/a and decreasing cell volume V with Cu doping. The energy difference between martensite and austenite also increases with Cu doping, which tends to elevate the TM. Cu doping can enhance the metallic bonding character in NiMn-based magnetic shape memory alloys (MSMAs) and is a grain refining strategy of their ribbons. The oriented columnar grains in In-rich samples change to fine equiaxial grains in Cu-rich samples. All this has a positive effect on the strength and ductility. The tensile strength of the Mn50Ni40Cu10 ribbon is 3.6 times higher than that of Mn50Ni40In6Cu4. So, Mn–Ni–Cu can be a promising all-d-metal Heusler alloy platform for developing MSMAs with interesting properties. [ABSTRACT FROM AUTHOR]

Magnetic shape memory alloys Mn2NiGa1−xCux (x = 0–0.7) melt-spun ribbons were synthesized, and their crystal structure, martensitic transformation, and magnetic and transport properties were studied. In Mn2NiGa1−xCux, unusual composition dependences of these properties were observed: the lattice parameter increases with Cu-doping, though Cu has a smaller atomic radius compared with Ga. The martensitic transformation temperature decreases with increasing Cu content at first and reaches a minimum at x = 0.3 and then increases rapidly as Cu content increases further. The variation tendency of magnetization is just opposite. When Cu content gets higher, a semiconductor-like to metal-like crossover in electron transport properties is observed. The martensite resistivity also changes from lower than that of austenite to higher than that. First-principles calculations indicate that these unusual properties are related to the competing occupation of Cu between A and D sites. Cu-doping can also enhance the metallic bonding in Mn2NiGa1−xCux, which can reduce the intrinsic brittleness and improve their mechanical properties. All this provides a fresh idea and method for the development of NiMn-based solid-state refrigeration materials. [ABSTRACT FROM AUTHOR]

Biological parameters extracted from electrical signals from various body parts have been used for many years to analyze the human body and its behavior. In addition, electrical signals from cancer cell lines, normal cells, and viruses, among others, have been widely used for the detection of various diseases. Single-cell parameters such as cell and cytoplasmic conductivity, relaxation frequency, and membrane capacitance are important. There are many techniques available to characterize biomaterials, such as nanotechnology, microstrip cavity resonance measurement, etc. This article reviews single-cell isolation and sorting techniques, such as the micropipette separation method, separation and sorting system (dual electrophoretic array system), DEPArray sorting system (dielectrophoretic array system), cell selector sorting system, and microfluidic and valve devices, and discusses their respective advantages and disadvantages. Furthermore, it summarizes common single-cell electrical manipulations, such as single-cell amperometry (SCA), electrical impedance sensing (EIS), impedance flow cytometry (IFC), cell-based electrical impedance (CEI), microelectromechanical systems (MEMS), and integrated microelectrode array (IMA). The article also enumerates the application and significance of single-cell electrochemical analysis from the perspectives of CTC liquid biopsy, recombinant adenovirus, tumor cells like lung cancer DTCs (LC-DTCs), and single-cell metabolomics analysis. The paper concludes with a discussion of the current limitations faced by single-cell analysis techniques along with future directions and potential application scenarios. [ABSTRACT FROM AUTHOR]