Magnetic composites have received increasing attention for electromagnetic wave absorption (EMA) applications. However, the practical EMA performance of these materials is still severely hampered by unmatched impedance characteristics and finite electromagnetic attenuation capacity. Controlling the components and building the architecture fabrication is necessary to solve these issues. Herein, a series of Fe3O4 , Fe3O4&Fe and Fe microspheres with flower-like hierarchical structure were constructed by a solvothermal method followed by an annealing process. The hierarchical structure and the synergistic effect of dielectric and magnetic loss capacity offer Fe3O4 a perfect impedance matching, providing an excellent EMA performance of a reflection loss (RL) of 67.9 dB and an effective absorption bandwidth (EAB) of 4.0 GHz. Meanwhile, the coordination of the hierarchical structure and the multiple components endow the Fe3O4&Fe composites with a RL as strong as 78.7 dB and an EAB as wide as 5.7 GHz (9.0-14.7 GHz) at 1.88 mm, which covers 75% X and 45% Ku bands. Such a remarkable lightweight and broad properties is due to the decent X band impedance matching and appropriate attenuation capacity. Therefore, this work highlights the significant of regulating the hierarchical structure and components to enhance the EMA performances.
Abstract Medical surgical catheters are widely used in the medical field for drug delivery or postoperative drainage. However, infections associated with local temperature rise often occur at the catheter‐tissue interface, resulting in irreversible pathological damage, cognitive behavioral abnormalities, or even an increased risk of mortality if not monitored in time. Herein, an in situ temperature‐sensing hydrogel coating on the outer surface of medical surgical catheters for real‐time infection monitoring is developed. The hydrogel coating exhibits a record temperature coefficient of resistance of 2.90% °C −1 and maintains stable in vivo. Besides, the hydrogel layer forms a mechanically compatible catheter‐tissue interface and minimizes the risk of inflammatory responses due to its tissue‐like softness (Young's modulus of 4.24 kPa). By applying it in the early detection of infections in the brain of SD rats, the individual survival rate has increased to 90% with timely intervention.
Electrochemical nitric oxide (NO) sensors are capable of real-time monitoring of intracranial NO concentration, which is crucial for understanding the functions of NO in the brain. However, traditional rigid electrochemical sensors used in the brain face the dilemma of low sensitivity and abnormal NO concentrations caused by neuroin-flammatory responses. Here, we report a highly sensitive and accurate electrochemical NO sensor that combines both physical and chemical adsorption capabilities for NO. The physical and chemical adsorption capabilities can be attributed to the high specific surface area and abundant carboxyl functional groups of the electrode, respectively. Besides, it is soft and matches the mechanical property of brain tissue, enabling an adaptable interface. The resulting NO sensor exhibits the highest reported sensitivity of 3245 pA nmol−1 L, with a low detection limit of 0.1 nmol L−1. No significant inflammatory response or excess NO expression is observed after implantation, improving the detection accuracy. The sensor successfully captures NO fluctuations in the brain and enables simultaneous NO detection in multiple brain regions, facilitating research on NO physio-pathological actions in the brain.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Implantable batteries are urgently needed as a power source to meet the demands of the next generation of biomedical electronic devices. However, existing implantable batteries suffer from unsatisfactory energy density, hindering the miniaturization of these devices. Here, a mitochondrion-inspired magnesium-oxygen biobattery that achieves both high energy density and biocompatibility in vivo is reported. The resulting biobattery exhibits a recorded energy density of 2517 Wh L-1 /1491 Wh kg-1 based on the total volume/mass of the device in vivo, which is ≈2.5 times higher than the current state-of-the-art, and can adapt to different environments for stable discharges. The volume of the magnesium-oxygen biobattery can be as thin as 0.015 mm3 and can be scaled up to 400 times larger without reducing the energy density. Additionally, it shows a stable biobattery/tissue interface, significantly reducing foreign body reactions. This work presents an effective strategy for the development of high-performance implantable batteries.
High salt environment was widespread in modern and geological record, and sedimentation induced by microbes in these systems was an important part of sedimentary minerals and rocks. The mechanism of microbiologically induced carbonate precipitation has not been solved thoroughly although numerous scholars and experts have made specifically research of the problems with respect to minerals induced by bacteria. The study of carbonate minerals induced by Halophilic bacteria has aroused wide concern. The present study was aim to investigate the characterization and process of biomineralization in the high salt system, a Halophilic bacterium, Chromohalobacter israelensis LD532 strain (Genbank: KX766026), which isolated from Yinjiashan Saltern of China, was selected as an object to induce carbonate minerals. Carbonate minerals induced by LD532 were investigated in several comparative experimental sets with Mg resources of magnesium sulfate and magnesium chloride. Magnesium calcite and aragonite were induced by LD532 bacteria while these minerals were not in the control group. The mineral phases, micromorphologies, and crystal structures were analyzed using X-ray powder diffraction, scanning electron microscope, and energy dispersive X-ray detector. Carbonic anhydrase and urease secreted by strain LD532 through metabolism promoted the pH values of the liquid medium and the process of carbonate precipitation. Further study proved that the nucleation sites of partial carbonate nucleus were located on the extracellular polymeric substance and the membrane of intracellular vesicles of LD532 bacteria by high resolution transmission electron microscopy, energy dispersive X-ray detector and ultrathin slices analysis, which provided favorable conditions for the growth of carbonate mineral crystals. The morphology and composition of minerals formed in MgSO4 and MgCl2 solution have significant differences, indicating that different sources of Mg2+ could also affect the physiological and biochemical activities of microorganisms and then affect the mineral deposition. The accomplished study is of certain interest for interpretation of the carbonates biomineraliazation in natural salt environment, and has a certain reference value in understand of the sedimentary carbonates in ancient marine environment like evaporated tidal flat.
Preparation process of ion-feedback barrier film (IBF) on Micro-channel Plate(MCP) is indispensable technology for the third generation image intensifier or even more image intensifier with high-performance. The technology of IBF is the best way to improve lifetime of image intensifier, to delay fatigue of photocathode because of the special substrate, for the traditional method of RF magnetron sputtering, sputtering atomic energy is too high, the film density is poor, the paper employs an alternative method of electron evaporation to prepare IBF, under the conditions of the working pressure: 2×10 -1 Pa, rating: 1.7Å/s, through changing the oxygen flowing and the evaporation time, the parameters are optimized to prepare more dense IBF. We explored the best evaporation time and O 2 flowing, under the test conditions, the IBF can be prepared with acceptable quality, eventually the optimum conditions of preparing IBF with high density is explored by electron beam evaporation technique.
Abstract Appropriate treatment of mass‐produced degraded batteries is desired to alleviate resource waste and environmental pollution caused by direct disposal. However, current technologies, which aim to recycle high‐value components from degraded batteries to refabricate new batteries, suffer from complex destruction‐refabrication processes and massive energy/resource inputs. Here it is found that without disassembling the degraded battery, the lost capacity is rejuvenated to its pristine state by simply applying electrical activation at a controlled voltage. It is shown that repeated application of electrical activation regenerates 22 life cycles for zinc‐ion batteries, increasing the total discharge energy by 78 times. The capacity rejuvenation by electrical activation originates from the transformation of redox‐inert Zn‐Mn‐O by‐products on the degraded cathode to redox‐active Mn‐O nanoribbons, which recovers diffusion kinetics of Zn 2+ /H + charge carriers. Simultaneously, the dendrites on the degraded anode are flattened to prevent short circuits while maintaining the electrolyte integrity. The electrical activation strategy is extendable to other batteries, such as lithium batteries, promising tremendous economic and environmental benefits. Besides, electrical activation rejuvenates implanted batteries to avoid the pain and hazards of replacing degraded batteries with conventional surgeries. This work presents a general and commercially viable route to treat degraded batteries.
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