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Subnanometer pores/channels (SNPCs) play crucial roles in regulating electrochemical redox reactions for rechargeable batteries. The delicately designed and tailored porous structure of SNPCs not only provides ample space for ion storage but also facilitates efficient ion diffusion within the electrodes in batteries, which can greatly improve the electrochemical performance. However, due to current technological limitations, it is challenging to synthesize and control the quality, storage, and transport of nanopores at the subnanometer scale, as well as to understand the relationship between SNPCs and performances. In this review, we systematically classify and summarize materials with SNPCs from a structural perspective, dividing them into one-dimensional (1D) SNPCs, two-dimensional (2D) SNPCs, and three-dimensional (3D) SNPCs. We also unveil the unique physicochemical properties of SNPCs and analyse electrochemical couplings in SNPCs for rechargeable batteries, including cathodes, anodes, electrolytes, and functional materials. Finally, we discuss the challenges that SNPCs may face in electrochemical reactions in batteries and propose future research directions.
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Superconducting diodes are proposed nonreciprocal circuit elements that should exhibit nondissipative transport in one direction while being resistive in the opposite direction. Multiple examples of such devices have emerged in the past couple of years; however, their efficiency is typically limited, and most of them require a magnetic field to function. Here we present a device that achieves efficiencies approaching 100% while operating at zero field. Our samples consist of a network of three graphene Josephson junctions linked by a common superconducting island, to which we refer as a Josephson triode. The three-terminal nature of the device inherently breaks the inversion symmetry, and the control current applied to one of the contacts breaks the time-reversal symmetry. The triode's utility is demonstrated by rectifying a small (nA scale amplitude) applied square wave. We speculate that devices of this type could be realistically employed in the modern quantum circuits.
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Lithium (Li) metal is one of the most promising anode materials for next-generation, high-energy, Li-based batteries due to its exceptionally high specific capacity and low reduction potential. Nonetheless, intrinsic challenges such as detrimental interfacial reactions, significant volume expansion, and dendritic growth present considerable obstacles to its practical application. This review comprehensively summarizes various recent strategies for the modification and protection of metallic lithium anodes, offering insight into the latest advancements in electrode enhancement, electrolyte innovation, and interfacial design, as well as theoretical simulations related to the above. One notable trend is the optimization of electrolytes to suppress dendrite formation and enhance the stability of the electrode-electrolyte interface. This has been achieved through the development of new electrolytes with higher ionic conductivity and better compatibility with Li metal. Furthermore, significant progress has been made in the design and synthesis of novel Li metal composite anodes. These composite anodes, incorporating various additives such as polymers, ceramic particles, and carbon nanotubes, exhibit improved cycling stability and safety compared to pure Li metal. Research has used simulation computing, machine learning, and other methods to achieve electrochemical mechanics modeling and multi-field simulation in order to analyze and predict non-uniform lithium deposition processes and control factors. In-depth investigations into the electrochemical reactions, interfacial chemistry, and physical properties of these electrodes have provided valuable insights into their design and optimization. It systematically encapsulates the state-of-the-art developments in anode protection and delineates prospective trajectories for the technology's industrial evolution. This review aims to provide a detailed overview of the latest strategies for enhancing metallic lithium anodes in lithium-ion batteries, addressing the primary challenges and suggesting future directions for industrial advancement.
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The quest for smart electronics with higher energy densities has intensified the development of high-voltage LiCoO2 (LCO). Despite their potential, LCO materials operating at 4.7â V faces critical challenges, including interface degradation and structural collapse. Herein, we propose a collective surface architecture through precise nanofilm coating and doping that combines an ultra-thin LiAlO2 coating layer and gradient doping of Al. This architecture not only mitigates side reactions, but also improves the Li+ migration kinetics on the LCO surface. Meanwhile, gradient doping of Al inhibited the severe lattice distortion caused by the irreversible phase transition of O3-H1-3-O1, thereby enhanced the electrochemical stability of LCO during 4.7â V cycling. DFT calculations further revealed that our approach significantly boosts the electronic conductivity. As a result, the modified LCO exhibited an outstanding reversible capacity of 230â mAh g-1 at 4.7â V, which is approximately 28 % higher than the conventional capacity at 4.5â V. To demonstrate their practical application, our cathode structure shows improved stability in full pouch cell configuration under high operating voltage. LCO exhibited an excellent cycling stability, retaining 82.33 % after 1000â cycles at 4.5â V. This multifunctional surface modification strategy offers a viable pathway for the practical application of LCO materials, setting a new standard for the development of high-energy-density and long-lasting electrode materials.
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We perform a systematic study of Andreev conversion at the interface between a superconductor and graphene in the quantum Hall (QH) regime. We find that the probability of Andreev conversion from electrons to holes follows an unexpected but clear trend: the dependencies on temperature and magnetic field are nearly decoupled. We discuss these trends and the role of the superconducting vortices, whose normal cores could both absorb and dephase the individual electrons in a QH edge. Our Letter may pave the road to engineering a future generation of hybrid devices for exploiting superconductivity proximity in chiral channels.
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The dynamical properties of multiterminal Josephson junctions (MT-JJs) have attracted interest, driven by the promise of new insights into synthetic topological phases of matter and Floquet states. This effort has culminated in the discovery of Cooper multiplets in which the splitting of a Cooper pair is enabled via a series of Andreev reflections that entangle four (or more) electrons. Here, we show that multiplet resonances can also emerge as a consequence of the three-terminal circuit model. The supercurrent appears due to correlated phase dynamics at values that correspond to the multiplet condition nV1 = -mV2 of applied bias. Multiplet resonances are seen in nanofabricated three-terminal graphene JJs, analog three-terminal JJ circuits, and circuit simulations. The stabilization of the supercurrent is purely dynamical, and a close analog to Kapitza's inverted pendulum problem. We describe parameter considerations that optimize the detection of the multiplet lines both for design of future devices.
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Electrones , VibraciónRESUMEN
The vanishing band gap of graphene has long presented challenges for making high-quality quantum point contacts (QPCs)âthe partially transparent p-n interfaces introduced by conventional split gates tend to short circuit the QPCs. This complication has hindered the fabrication of graphene quantum Hall Fabry-Pérot interferometers, until recent advances have allowed split-gate QPCs to operate utilizing the highly resistive ν = 0 state. Here, we present a simple recipe to fabricate QPCs by etching a narrow trench in the graphene sheet to separate the conducting channel from self-aligned graphene side gates. We demonstrate operation of the individual QPCs in the quantum Hall regime and further utilize these QPCs to create and study a quantum Hall interferometer.
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GrafitoRESUMEN
For practical sodium-ion batteries, both high electrochemical performance and cost efficiency of the electrode materials are considered as two key parameters. Prussian blue analogues (PBAs) are broadly recognized as promising cathode materials due to their low cost, high theoretical capacity, and cycling stability, although they suffer from low-crystallinity-induced performance deterioration. Herein, a facile "ice-assisted" strategy is presented to prepare highly crystallized PBAs without any additives. By suppressing structure defects, the cathode exhibits a high capacity of 123 mAh g-1 with initial Coulombic efficiency of 87.2%, a long cycling lifespan of 3000 cycles, and significantly enhanced high/low temperature performance and calendar life. Remarkably, the low structure distortion and high sodium diffusion coefficient have been identified via in situ synchrotron powder diffraction and first-principles calculations, while its thermal stability has been analyzed by in situ heated X-ray powder diffraction. We believe the results could pave the way to the low-cost and large-scale application of PBAs in all-climate sodium-ion batteries.
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The development of a stable and highly active photocatalyst has garnered significant attention in the field of wastewater treatment. In this study, a novel technique involving a facile stirring method was devised to fabricate an array of g-C3N4/ZnO nanowire (ZnO NW) composites. Through the introduction of g-C3N4 to augment the generation of electron-hole pairs upon exposure to light, the catalytic efficacy of these composites was found to surpass that of the pristine ZnO NWs when subjected to simulated sunlight. The photocatalytic performance of a 20 mg·L-1 methylene blue solution was found to be highest when the doping rate was 25 wt%, resulting in a degradation rate of 99.1% after 60 min. The remarkable enhancement in catalytic efficiency can be ascribed to the emergence of a captivating hetero-junction at the interface of g-C3N4 and ZnO NWs, characterized by a harmoniously aligned band structure. This alluring arrangement effectively curtailed charge carrier recombination, amplified light absorption, and augmented the distinct surface area, culminating in a notable boost to the photocatalytic prowess. These findings suggest that the strategic engineering of g-C3N4/ZnO NW heterostructures holds tremendous promise as a pioneering avenue for enhancing the efficacy of wastewater treatment methodologies.
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Prussian blue analogues (PBAs) have been regarded as promising cathode materials for alkali-ion batteries owing to their high theoretical energy density and low cost. However, the high water and vacancy content of PBAs lower their energy density and bring safety issues, impeding their large-scale application. Herein, a facile "potassium-ions assisted" strategy is proposed to synthesize highly crystallized PBAs. By manipulating the dominant crystal plane and suppressing vacancies, the as-prepared PBAs exhibit increased redox potential resulting in high energy density up to ≈450â Wh kg-1 , which is at the same level of the well-known LiFePO4 cathodes for lithium-ion batteries. Remarkably, unconventional highly-reversible phase evolution and redox-active pairs were identified by multiple in situ techniques for the first time. The preferred guest-ion storage sites and migration mechanism were systematically analysed through theoretical calculations. We believe these results could inspire the design of safe with high energy density.
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When a Josephson junction is exposed to microwave radiation, it undergoes the inverse AC Josephson effectâthe phase of the junction locks to the drive frequency. As a result, the I-V curves of the junction acquire "Shapiro steps" of quantized voltage. If the junction has three or more superconducting contacts, coupling between different pairs of terminals must be taken into account and the state of the junction evolves in a phase space of higher dimensionality. Here, we study the multiterminal inverse AC Josephson effect in a graphene sample with three superconducting terminals. We observe robust fractional Shapiro steps and correlated switching events, which can only be explained by considering the device as a completely connected Josephson network. We successfully simulate the observed behaviors using a modified two-dimensional RCSJ model. Our results suggest that multiterminal Josephson junctions are a playground to study highly connected nonlinear networks with novel topologies.
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Transient ischaemia and reperfusion in liver tissue induce hepatic ischaemia/reperfusion (I/R) tissue injury and a profound inflammatory response in vivo. Hepatic I/R can be classified into warm I/R and cold I/R and is characterized by three main types of cell death, apoptosis, necrosis and autophagy, in rodents or patients following I/R. Warm I/R is observed in patients or animal models undergoing liver resection, haemorrhagic shock, trauma, cardiac arrest or hepatic sinusoidal obstruction syndrome when vascular occlusion inhibits normal blood perfusion in liver tissue. Cold I/R is a condition that affects only patients who have undergone liver transplantation (LT) and is caused by donated liver graft preservation in a hypothermic environment prior to entering a warm reperfusion phase. Under stress conditions, autophagy plays a critical role in promoting cell survival and maintaining liver homeostasis by generating new adenosine triphosphate (ATP) and organelle components after the degradation of macromolecules and organelles in liver tissue. This role of autophagy may contribute to the protection of hepatic I/R-induced liver injury; however, a considerable amount of evidence has shown that autophagy inhibition also protects against hepatic I/R injury by inhibiting autophagic cell death under specific circumstances. In this review, we comprehensively discuss current strategies and underlying mechanisms of autophagy regulation that alleviates I/R injury after liver resection and LT. Directed autophagy regulation can maintain liver homeostasis and improve liver function in individuals undergoing warm or cold I/R. In this way, autophagy regulation can contribute to improving the prognosis of patients undergoing liver resection or LT.
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Autofagia , Hepatopatías/etiología , Hepatopatías/metabolismo , Sustancias Protectoras/farmacología , Daño por Reperfusión/etiología , Daño por Reperfusión/metabolismo , Animales , Apoptosis/efectos de los fármacos , Autofagia/efectos de los fármacos , Biomarcadores , Manejo de la Enfermedad , Susceptibilidad a Enfermedades , Regulación de la Expresión Génica/efectos de los fármacos , Hepatectomía/efectos adversos , Hepatectomía/métodos , Humanos , Precondicionamiento Isquémico/métodos , Hepatopatías/patología , Hepatopatías/prevención & control , Trasplante de Hígado/efectos adversos , Trasplante de Hígado/métodos , Mitocondrias Hepáticas/efectos de los fármacos , Mitocondrias Hepáticas/metabolismo , Mitofagia , Sustancias Protectoras/uso terapéutico , Daño por Reperfusión/patología , Daño por Reperfusión/prevención & control , Transducción de Señal/efectos de los fármacosRESUMEN
Organ preservation is a prerequisite for an urgent increase in the availability of organs for solid organ transplantation (SOT). An increasing amount of expanded criteria donor (ECD) organs are used clinically. Currently, the paradigm of organ preservation is shifting from simple reduction of cellular metabolic activity to maximal simulation of an ex vivo physiological microenvironment. An ideal organ preservation technique should not only preserve isolated organs but also offer the possibility of rehabilitation and evaluation of organ function prior to transplantation. Based on the fact that mesenchymal stromal cells (MSCs) possess strong regeneration properties, the combination of MSCs with machine perfusion (MP) is expected to be superior to conventional preservation methods. In recent years, several studies have attempted to use this strategy for SOT showing promising outcomes. With better organ function during ex vivo preservation and the potential of utilization of organs previously deemed untransplantable, this strategy is meaningful for patients with organ failure to help overcome organ shortage in the field of SOT.
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Células Madre Mesenquimatosas/metabolismo , Preservación de Órganos/métodos , Trasplante de Órganos/métodos , Perfusión/métodos , Medicina Regenerativa/métodos , HumanosRESUMEN
The AC Josephson effect manifests itself in the form of "Shapiro steps" of quantized voltage in Josephson junctions subject to radiofrequency (RF) radiation. This effect presents an early example of a driven-dissipative quantum phenomenon and is presently utilized in primary voltage standards. Shapiro steps have also become one of the standard tools to probe junctions made in a variety of novel materials. Here we study Shapiro steps in a widely tunable graphene-based Josephson junction in which the high-frequency dynamics is determined by the on-chip environment. We investigate the variety of patterns that can be obtained in this well-understood system depending on the carrier density, temperature, RF frequency, and magnetic field. Although the patterns of Shapiro steps can change drastically when just one parameter is varied, the overall trends can be understood and the behaviors straightforwardly simulated, showing some key differences from the conventional RCSJ model. The resulting understanding may help interpret similar measurements in more complex materials.
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Cell-to-cell communication and information exchange is one of the most important events in multiple physiological processes, including multicellular organism development, cellular function regulation, external stress response, homeostasis maintenance and tissue regeneration. New findings support the concept that subcellular component delivery may account for the beneficial effects of mesenchymal stem cell (MSC)-based therapy-mediated protection against acute kidney injury (AKI). Through the secretion of extracellular vesicles (EVs), formation of tunnelling nanotubes (TNTs) and development of cellular fusions, a broad range of subcellular components, including proteins, nucleic acids (mRNA and miRNA) or even organelles can be transferred from MSCs into injured renal cells, significantly promoting cell survival, favouring tissue repair and accelerating renal recovery. In this review, we outline an extensive and detailed description of the regenerative consequences of subcellular component delivery from MSCs into injured renal cells during AKI, by which the potential mechanism underlying MSC-based therapies against AKI can be elucidated.
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Lesión Renal Aguda/terapia , Vesículas Extracelulares/metabolismo , Células Madre Mesenquimatosas/citología , Regeneración , Animales , Comunicación Celular , Diferenciación Celular , Homeostasis , Humanos , Riñón/metabolismo , Trasplante de Células Madre Mesenquimatosas , Ratones , MicroARNs/metabolismo , Nanotubos/química , ARN Mensajero/metabolismo , Ratas , Medicina Regenerativa , Transducción de SeñalRESUMEN
Acute liver injury (ALI) induced by chemicals in current experimental studies is characterized by inflammation, oxidative stress and necrosis, which can greatly influence the long-term outcome and lead to liver failure. In liver cells, different autophagy forms envelop cytoplasm components, including proteins, endoplasmic reticulum (ER), mitochondria and lipids, and they effectively participate in breaking down the cargo enclosed inside lysosomes to replenish cellular energy and contents. In general, autophagy serves as a cell survival mechanism in stressful microenvironments, but it also serves as a destructive mechanism that results in cell death in vitro and in vivo. In experimental animals, multiple chemicals are used to mimic ALI in patients to clarify the potential pathological mechanisms and develop effective strategies in the clinic. In this review, we summarize related publications about autophagy modulation to attenuate chemically induced ALI in vitro and in vivo. We also analysed the underlying mechanisms of autophagy regulators and genetic modifications to clarify how to control autophagy to protect against chemically induced ALI in animal models. We anticipate that selectively controlling the dual effects of hepatic autophagy will help to protect against ALI in various animals, but the detailed mechanisms and effects should be determined further in future studies. In this way, we are more confident that modulating autophagy in liver regeneration can improve the prognosis of ALI.
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Lesión Pulmonar Aguda/patología , Autofagia/fisiología , Animales , Modelos Animales de Enfermedad , Humanos , Hígado/patología , Regeneración Hepática/fisiología , PronósticoRESUMEN
Based on multiple studies in animal models, mesenchymal stem cell (MSC)-based therapy appears to be an innovative intervention approach with tremendous potential for the management of kidney disease. However, the clinical therapeutic effects of MSCs in either acute kidney injury (AKI) or chronic kidney disease (CKD) are still under debate. Hurdles originate from the harsh microenvironment in vivo that decreases the cell survival rate, paracrine activity and migratory capacity of MSCs after transplantation, which are believed to be the main reasons for their limited effects in clinical applications. Melatonin is traditionally regarded as a circadian rhythm-regulated neurohormone but in recent years has been found to exhibit antioxidant and anti-inflammatory properties. Because inflammation, oxidative stress, thermal injury, and hypoxia are abnormally activated in kidney disease, application of melatonin preconditioning to optimize the MSC response to the hostile in vivo microenvironment before transplantation is of great importance. In this review, we discuss current knowledge concerning the beneficial effects of melatonin preconditioning in MSC-based therapy for kidney disease. By summarizing the available information and discussing the underlying mechanisms, we aim to improve the therapeutic effects of MSC-based therapy for kidney disease and accelerate translation to clinical application.
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Antioxidantes/farmacología , Enfermedades Renales/terapia , Melatonina/farmacología , Trasplante de Células Madre Mesenquimatosas/métodos , Células Madre Mesenquimatosas/citología , Acondicionamiento Pretrasplante , Animales , Humanos , Enfermedades Renales/patología , Células Madre Mesenquimatosas/efectos de los fármacosRESUMEN
The liver is composed of hepatocytes, cholangiocytes, Kupffer cells, sinusoidal endothelial cells, hepatic stellate cells (HSCs) and dendritic cells; all these functional and interstitial cells contribute to the synthesis and secretion functions of liver tissue. However, various hepatotoxic factors including infection, chemicals, high-fat diet consumption, surgical procedures and genetic mutations, as well as biliary tract diseases such as sclerosing cholangitis and bile duct ligation, ultimately progress into liver cirrhosis after activation of fibrogenesis. Melatonin (MT), a special hormone isolated from the pineal gland, participates in regulating multiple physiological functions including sleep promotion, circadian rhythms and neuroendocrine processes. Current evidence shows that MT protects against liver injury by inhibiting oxidation, inflammation, HSC proliferation and hepatocyte apoptosis, thereby inhibiting the progression of liver cirrhosis. In this review, we summarize the circadian rhythm of liver cirrhosis and its potential mechanisms as well as the therapeutic effects of MT on liver cirrhosis and earlier-stage liver diseases including liver steatosis, nonalcoholic fatty liver disease and liver fibrosis. Given that MT is an antioxidative and anti-inflammatory agent that is effective in eliminating liver injury, it is a potential agent with which to reverse liver cirrhosis in its early stage.
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Antioxidantes/farmacología , Cirrosis Hepática/patología , Cirrosis Hepática/prevención & control , Melatonina/farmacología , Sustancias Protectoras/farmacología , Animales , HumanosRESUMEN
End-stage liver fibrosis frequently progresses to portal vein thrombosis, formation of oesophageal varices, hepatic encephalopathy, ascites, hepatocellular carcinoma and liver failure. Mesenchymal stem cells (MSCs), when transplanted in vivo, migrate into fibrogenic livers and then differentiate into hepatocyte-like cells or fuse with hepatocytes to protect liver function. Moreover, they can produce various growth factors and cytokines with anti-inflammatory effects to reverse the fibrotic state of the liver. In addition, only a small number of MSCs migrate to the injured tissue after cell transplantation; consequently, multiple studies have investigated effective strategies to improve the survival rate and activity of MSCs for the treatment of liver fibrosis. In this review, we intend to arrange and analyse the current evidence related to MSC transplantation in liver fibrosis, to summarize the detailed mechanisms of MSC transplantation for the reversal of liver fibrosis and to discuss new strategies for this treatment. Finally, and most importantly, we will identify the current problems with MSC-based therapies to repair liver fibrosis that must be addressed in order to develop safer and more effective routes for MSC transplantation. In this way, it will soon be possible to significantly improve the therapeutic effects of MSC transplantation for liver regeneration, as well as enhance the quality of life and prolong the survival time of patients with liver fibrosis.
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Cirrosis Hepática/terapia , Regeneración Hepática , Trasplante de Células Madre Mesenquimatosas/métodos , Células Madre Mesenquimatosas/citología , Animales , Diferenciación Celular , Humanos , Cirrosis Hepática/patologíaRESUMEN
Acute kidney injury (AKI) is a common, severe emergency case in clinics, with high incidence, significant mortality and increased costs. Despite development in the understanding of its pathophysiology, the therapeutic choices are still confined to dialysis and renal transplantation. Considering their antiapoptotic, immunomodulatory, antioxidative and pro-angiogenic effects, mesenchymal stem cells (MSCs) may be a promising candidate for AKI management. Based on these findings, some clinical trials have been performed, but the results are contradictory (NCT00733876, NCT01602328). The low engraftment, poor survival rate, impaired paracrine ability and delayed administration of MSCs are the four main reasons for the limited clinical efficacy. Investigators have developed a series of preconditioning strategies to improve MSC survival rates and paracrine ability. In this review, by summarizing these encouraging studies, we intend to provide a comprehensive understanding of various preconditioning strategies on AKI therapy and improve the prognosis of AKI patients by regenerative medicine.