Light-Induced Mott-Insulator-to-Metal Phase Transition in Ultrathin Intermediate-Spin Ferromagnetic Perovskite Ruthenates.

Light control of emergent quantum phenomena is a widely used external stimulus for quantum materials. Generally, perovskite strontium ruthenate SrRuO3 has an itinerant ferromagnetism with a low-spin state. However, the phase of intermediate-spin (IS) ferromagnetic metallic state has never been seen. Here, by means of UV-light irradiation, a photocarrier-doping-induced Mott-insulator-to-metal phase transition is shown in a few atomic layers of perovskite IS ferromagnetic SrRuO3- δ . This new metastable IS metallic phase can be reversibly regulated due to the convenient photocharge transfer from SrTiO3 substrates to SrRuO3- δ ultrathin films. These dynamical mean-field theory calculations further verify such photoinduced electronic phase transformation, owing to oxygen vacancies and orbital reconstruction. The optical manipulation of charge-transfer finesse is an alternative pathway toward discovering novel metastable phases in strongly correlated systems and facilitates potential light-controlled device applications in optoelectronics and spintronics.

Revealing the Origin of Transition-Metal Migration in Layered Sodium-Ion Battery Cathodes: Random Na Extraction and Na-Free Layer Formation.

Cation migration often occurs in layered oxide cathodes of lithium-ion batteries due to the similar ion radius of Li and transition metals (TMs). Although Na and TM show a big difference of ion radius, TMs in layered cathodes of sodium-ion batteries (SIBs) can still migrate to Na layer, leading to serious electrochemical degeneration. To elucidate the origin of TM migration in layered SIB cathodes, we choose NaCrO2 , a typical layered cathode suffering from serious TM migration, as a model material and find that the TM migration is derived from the random desodiation and subsequent formation of Na-free layer at high charge potential. A Ru/Ti co-doping strategy is developed to address the issue, where the doped active Ru is first oxidized to create a selective desodiation and the doped inactive Ti can function as a pillar to avoid complete desodiation in Ru-contained TM layers, leading to the suppression of the Na-free layer formation and subsequent enhanced electrochemical performance.

Anatomic resection versus radiofrequency ablation with an ablative margin ≥ 1.0 cm for solitary small hepatocellular carcinoma measuring ≤ 3 cm: Comparison of long-term outcomes using propensity score matching analysis.

PURPOSE: To compare the long-term outcomes of anatomic resection (AR) and radiofrequency ablation (RFA) with an ablative margin (AM) of ≥ 1.0 cm as first-line treatment for solitary hepatocellular carcinoma measuring ≤ 3 cm. METHODS: Two hundred and fifty-one patients who underwent AR (n = 156) or RFA (ablative margin ≥ 1.0 cm, n = 95) at any of 6 tertiary hospitals from 2009 to 2018 were enrolled. Propensity score matched analysis (PSM) were used to compare overall survival (OS), recurrence-free survival (RFS), and perioperative outcomes. Univariate and multivariate analyses were performed to identify prognostic factors associated with RFS and OS. RESULTS: PSM created 67 patient-pairs. After 96 months of follow-up, RFA with an ablative margin ≥ 1.0 cm and AR showed comparable 1-year, 3-year, 5-year, and 8-year OS rates before (P = 0.580) and after (P = 0.640) PSM. However, RFS was better at 1, 3, 5, and 8 years after AR before (P = 0.0036) and after (P = 0.017) PSM. The operation time and postoperative hospital stay were significantly longer in the AR group than in the RFA group before and after PSM (P < 0.05). Multivariate analysis identified age and type of treatment to be independent prognostic factors for RFS and age and hepatitis C to be associated with OS. CONCLUSIONS: Long-term OS was not significantly different between AR and RFA with an AM ≥ 1.0 cm in patients with a solitary hepatocellular carcinoma measuring ≤ 3 cm; but, RFS appeared to be better after AR than after RFA. However, RFA was associated with fewer perioperative complications and a shorter postoperative hospital stay.

Enhanced polarization and abnormal flexural deformation in bent freestanding perovskite oxides.

Recent realizations of ultrathin freestanding perovskite oxides offer a unique platform to probe novel properties in two-dimensional oxides. Here, we observe a giant flexoelectric response in freestanding BiFeO3 and SrTiO3 in their bent state arising from strain gradients up to 3.5 × 107 m-1, suggesting a promising approach for realizing ultra-large polarizations. Additionally, a substantial change in membrane thickness is discovered in bent freestanding BiFeO3, which implies an unusual bending-expansion/shrinkage effect in the ferroelectric membrane that has never been seen before in crystalline materials. Our theoretical model reveals that this unprecedented flexural deformation within the membrane is attributable to a flexoelectricity-piezoelectricity interplay. The finding unveils intriguing nanoscale electromechanical properties and provides guidance for their practical applications in flexible nanoelectromechanical systems.

Non-invasive digital etching of van der Waals semiconductors.

The capability to finely tailor material thickness with simultaneous atomic precision and non-invasivity would be useful for constructing quantum platforms and post-Moore microelectronics. However, it remains challenging to attain synchronized controls over tailoring selectivity and precision. Here we report a protocol that allows for non-invasive and atomically digital etching of van der Waals transition-metal dichalcogenides through selective alloying via low-temperature thermal diffusion and subsequent wet etching. The mechanism of selective alloying between sacrifice metal atoms and defective or pristine dichalcogenides is analyzed with high-resolution scanning transmission electron microscopy. Also, the non-invasive nature and atomic level precision of our etching technique are corroborated by consistent spectral, crystallographic, and electrical characterization measurements. The low-temperature charge mobility of as-etched MoS2 reaches up to 1200 cm2 V-1s-1, comparable to that of exfoliated pristine counterparts. The entire protocol represents a highly precise and non-invasive tailoring route for material manipulation.

Atomically Intimate Solid Electrolyte/Electrode Contact Capable of Surviving Long-Term Cycling with Repeated Phase Transitions.

The electrode-electrolyte contact issue within the composite electrode layer is a grand challenge for all-solid-state Li batteries. In order to achieve cycling performances comparable to Li-ion batteries based on liquid electrolyte, the aforementioned solid-solid contact not only needs to be sufficiently thorough but also must tolerate repeated cycling. Simultaneously meeting both requirements is rather challenging. Here, we discover that epitaxy may effectively overcome such bottlenecks even when the electrode undergoes repeated phase transitions during cycling. Through epitaxial growth, the perovskite Li0.33La0.56TiO3 solid electrolyte was found capable of forming atomically intimate contact with both the spinel Li4Ti5O12 and rock-salt Li7Ti5O12. In contrast to conventional expectations, such epitaxial interfaces can also survive repeated spinel-to-rock-salt phase transitions. Consequently, the Li4Ti5O12-Li0.33La0.56TiO3 composite electrode based on epitaxial solid-solid contact delivers not only a rate capability comparable to that of the surry-cast one with solid-liquid contact but also an excellent long-term cycling stability.

Hydrogel Loaded with VEGF/TFEB-Engineered Extracellular Vesicles for Rescuing Critical Limb Ischemia by a Dual-Pathway Activation Strategy.

Critical limb ischemia (CLI) is the most severe clinical manifestation of peripheral arterial disease, which causes many amputations and deaths. Conventional treatment strategies for CLI (e.g., stent implantation and vascular surgery) bring surgical risk, which are not suitable for each patient. Extracellular vesicles (EVs) can be a potential solution for CLI. Herein, vascular endothelial growth factor (VEGF; i.e., a crucial molecule related to angiogenesis) and transcription factor EB (TFEB; i.e., a pivotal regulator of autophagy) are chosen as the target gene to improve the bioactivity of EVs derived from endothelial cells. The VEGF/TFEB-engineered EVs (Engineered-EVs) are fabricated by genetically engineering the parent cells, and their versatile functions are confirmed using three cell models (human umbilical vein endothelial cells, myoblast, and monocytes). Injectable thermal-responsive hydrogel are then combined with Engineered-EVs to combat CLI. These results reveal that the hydrogel can enhance the stability of Engineered-EVs in vivo and release EVs at different temperatures. Moreover, the results of animal studies indicate that Engineered-EV/Hydrogel can significantly improve neovascularization, attenuate muscle injury, and recover limb function after CLI. Finally, mechanistic studies shed light on the therapeutic effect of Engineered-EV/Hydrogel due to the activated VEGF/VEGFR pathway and autophagy-lysosomal pathway.

Anomalous Superconducting Proximity Effect in Bi2 Se3 /FeSe0.5 Te0.5 Thin-Film Heterojunctions.

The superconducting proximity effect (SPE) induces a superconductivity transition in otherwise non-superconducting thin films in proximity with a superconductor. The SPE usually occurs in real space and decays exponentially with film thickness. Herein, an abnormal SPE in a topological insulator (TI)/superconductor heterostructure is unveiled, which is attributed to the topologically protected surface state. Surprisingly, such abnormal SPE occurs in momentum space regardless of the TI film thickness, as long as the topological surface states are robust and form a continuous conduction loop. Combining transport measurements and scanning tunneling microscopy/spectroscopy techniques, the SPE in Bi2 Se3 /FeSe0.5 Te0.5 heterostructures is explored, where Bi2 Se3 is an ideal 3D topological insulator and FeSe0.5 Te0.5 a typical iron-based superconductor. As the thickness of the Bi2 Se3 thin film exceeds 400 nm, there still exists SPE-induced superconductivity on the surface of Bi2 Se3 thin film with a transition temperature Tc not less than 10 K. Such an extraordinary behavior is induced by the unique properties of topologically protected surface states of Bi2 Se3 . This research deepens the understanding of the important role of topologically protected surface states in the SPE.

Hydrogel-based therapeutic angiogenesis: An alternative treatment strategy for critical limb ischemia.

Critical limb ischemia (CLI) is the most severe clinical manifestation of peripheral arterial disease (PAD), resulting in the total or partial loss of limb function. Although the conventional treatment strategy of CLI (e.g., medical treatment and surgery) can improve blood perfusion and restore limb function, many patients are unsuitable for these strategies and they still face the threats of amputation or death. Therapeutic angiogenesis, as a potential solution for these problems, attempts to manipulate blood vessel growth in vivo for augment perfusion without the help of extra pharmaceutics and surgery. With the rise of interdisciplinary research, regenerative medicine strategies provide new possibilities for treating many clinical diseases. Hydrogel, as an excellent biocompatibility material, is an ideal candidate for delivering bioactive molecules and cells for therapeutic angiogenesis. Besides, hydrogel could precisely deliver, control release, and keep the bioactivity of cargos, making hydrogel-based therapeutic angiogenesis a new strategy for CLI therapy. In this review, we comprehensively discuss the approaches of hydrogel-based strategy for CLI treatment as well as their challenges, and future directions.

Pinning Effect Enhanced Structural Stability toward a Zero-Strain Layered Cathode for Sodium-Ion Batteries.

Layered oxides as the cathode materials of sodium-ion batteries are receiving extensive attention due to their high capacity and flexible composition. However, the layered cathode tends to be thermodynamically and electrochemically unstable during (de)sodiation. Herein, we propose the pinning effect and controllable pinning point in sodium storage layered cathodes to enhance the structural stability and achieve optimal electrochemical performance. 0 %, 2.5 % and 7.3 % transition-metal occupancies in Na-site as pinning points are obtained in Na0.67 Mn0.5 Co0.5-x Fex O2 . 2.5 % Na-site pinned by Fe3+ is beneficial to restrain the potential slab sliding and enhance the structural stability, resulting in an ultra-low volume variation of 0.6 % and maintaining the smooth two-dimensional channel for Na-ion transfer. The Na0.67 Mn0.5 Co0.4 Fe0.1 O2 cathode with the optimal Fe3+ pinning delivers outstanding cycle performance of over 1000 cycles and superior rate capability up to 10 C.

Nanopharmaceutical-based regenerative medicine: a promising therapeutic strategy for spinal cord injury.

Spinal cord injury (SCI) is a neurological disorder that can lead to loss of perceptive and athletic function due to the severe nerve damage. To date, pieces of evidence detailing the precise pathological mechanisms in SCI are still unclear. Therefore, drug therapy cannot effectively alleviate the SCI symptoms and faces the limitations of systemic administration with large side effects. Thus, the development of SCI treatment strategies is urgent and valuable. Due to the application of nanotechnology in pharmaceutical research, nanopharmaceutical-based regenerative medicine will bring colossal development space for clinical medicine. These nanopharmaceuticals (i.e. nanocrystalline drugs and nanocarrier drugs) are designed using different types of materials or bioactive molecules, so as to improve the therapeutic effects, reduce side effects, and subtly deliver drugs, etc. Currently, an increasing number of nanopharmaceutical products have been approved by drug regulatory agencies, which has also prompted more researchers to focus on the potential treatment strategies of SCI. Therefore, the purpose of this review is to summarize and elaborate the research progress as well as the challenges and future of nanopharmaceuticals in the treatment of SCI, aiming to promote further research of nanopharmaceuticals in SCI.

Tunnel Intergrowth Lix MnO2 Nanosheet Arrays as 3D Cathode for High-Performance All-Solid-State Thin Film Lithium Microbatteries.

All-solid-state thin film lithium batteries (TFBs) are proposed as the ideal power sources for microelectronic devices. However, the high-temperature (>500 °C) annealing process of cathode films, such as LiCoO2 and LiMn2 O4, restricts the on-chip integration and potential applications of TFBs. Herein, tunnel structured Lix MnO2 nanosheet arrays are fabricated as 3D cathode for TFBs by a facile electrolyte Li+ ion infusion method at very low temperature of 180 °C. Featuring an interesting tunnel intergrowth structure consisting of alternating 1 × 3 and 1 × 2 tunnels, the Lix MnO2 cathode shows high specific capacity with good structural stability between 2.0 and 4.3 V (vs. Li+ /Li). By utilizing the 3D Lix MnO2 cathode, all-solid-state Lix MnO2 /LiPON/Li TFB (3DLMO-TFB) has been successfully constructed with prominent advantages of greatly enriched cathode/electrolyte interface and shortened Li+ diffusion length in the 3D structure. Consequently, the 3DLMO-TFB device exhibits large specific capacity (185 mAh g-1 at 50 mA g-1 ), good rate performance, and excellent cycle performance (81.3% capacity retention after 1000 cycles), outperforming the TFBs using spinel LiMn2 O4 thin film cathodes fabricated at high temperature. Importantly, the low-temperature preparation of high-performance cathode film enables the fabrication of TFBs on various rigid and flexible substrates, which could greatly expand their potential applications in microelectronics.

Core-Shell Layered Oxide Cathode for High-Performance Sodium-Ion Batteries.

Sodium layered oxides are considered to be cathode candidates with the most potential for large-scale energy storage because of their high reversible capacity and wide availability of sodium resources. A significant hurdle to wide application of these layered oxides lies in simultaneously satisfying high-energy density and long cycle life because of the intrinsic problems associated with their structural irreversibility. Herein, a O3/O'3-P2 core-shell composite that integrates a high specific capacity from O-type Ni-based core and good structural stability from P2-type Mn-rich shell is presented. Multiscale electron microscopy and affiliated spectroscopy analyses reveal that, in addition to the microscale O3/O'3-P2 core-shell structure, a nanoscale coherent P2/O3 intergrown structure can also be identified in the composite. Such well-tailored structures not only constrain the structural damages (microscale cracks) induced by repeated volumetric changes upon desodiation and resodiation but also facilitate fast Na ions diffusion through the exterior P2-type layered structure. This work may provide new clues into the design of high-performance cathode materials for sodium-ion batteries.

Electrochemical and Structural Analysis in All-Solid-State Lithium Batteries by Analytical Electron Microscopy: Progress and Perspectives.

Advanced scanning transmission electron microscopy (STEM) and its associated instruments have made significant contributions to the characterization of all-solid-state (ASS) Li batteries, as these tools provide localized information on the structure, morphology, chemistry, and electronic state of electrodes, electrolytes, and their interfaces at the nano- and atomic scale. Furthermore, the rapid development of in situ techniques has enabled a deep understanding of interfacial dynamic behavior and heterogeneous characteristics during the cycling process. However, due to the beam-sensitive nature of light elements in the interphases, e.g., Li and O, thorough and reliable studies of the interfacial structure and chemistry at an ultrahigh spatial resolution without beam damage is still a formidable challenge. Herein, the following points are discussed: (1) the recent contributions of advanced STEM to the study of ASS Li batteries; (2) current challenges associated with using this method; and (3) potential opportunities for combining cryo-electron microscopy and the STEM phase contrast imaging techniques.

Precision Printing of Customized Cylindrical Capsules with Multifunctional Layers for Oral Drug Delivery.

Advances in personalized medicine will require custom drug formulations and delivery mechanisms. Herein, we demonstrate a new type of personalized capsule comprising of printed concentric cylindrical layers with each layer having a distinctive functional drug component. Poly ε-caprolactone (PCL) with paracetamol (APAP) and chlorpheniramine maleate (CM), synergistic drugs commonly used to alleviate influenza symptoms, are printed as an inner layer and outer layer, respectively, via microscaled electrohydrodynamic (EHD) printing. Polyvinylpyrrolidone (PVP) nanofibers are embedded as interlayers between the two printed PCL-drug layers using electrospinning (ES) techniques. The complete concentric cylindrical capsule with a 6 mm inner diameter and 15 mm length can be swallowed for oral drug delivery. After dissolution of the PVP interlayer, the capsule separates in two, with inner and outer capsules for continuous drug dosing and targeting. Imaging was achieved using a 3T MRI system which allowed temporal observations of the targeted release through the incorporation of nanoparticles (Fe3O4). The morphology and structure, chemical composition, mechanical properties, and biocompatibility of the capsules were studied in vitro. In summary, this new type of custom printed and electrospun capsule that enabled component separation, targeted drug release may advance personalized medicine via multidrug oral delivery.

Freestanding crystalline oxide perovskites down to the monolayer limit.

Two-dimensional (2D) materials such as graphene and transition-metal dichalcogenides reveal the electronic phases that emerge when a bulk crystal is reduced to a monolayer1-4. Transition-metal oxide perovskites host a variety of correlated electronic phases5-12, so similar behaviour in monolayer materials based on transition-metal oxide perovskites would open the door to a rich spectrum of exotic 2D correlated phases that have not yet been explored. Here we report the fabrication of freestanding perovskite films with high crystalline quality almost down to a single unit cell. Using a recently developed method based on water-soluble Sr3Al2O6 as the sacrificial buffer layer13,14 we synthesize freestanding SrTiO3 and BiFeO3 ultrathin films by reactive molecular beam epitaxy and transfer them to diverse substrates, in particular crystalline silicon wafers and holey carbon films. We find that freestanding BiFeO3 films exhibit unexpected and giant tetragonality and polarization when approaching the 2D limit. Our results demonstrate the absence of a critical thickness for stabilizing the crystalline order in the freestanding ultrathin oxide films. The ability to synthesize and transfer crystalline freestanding perovskite films without any thickness limitation onto any desired substrate creates opportunities for research into 2D correlated phases and interfacial phenomena that have not previously been technically possible.

Porous Yolk-Shell Particle Engineering via Nonsolvent-Assisted Trineedle Coaxial Electrospraying for Burn-Related Wound Healing.

Yolk-shell particles (YSPs) have attracted increasing attention from various research fields because of their low density, large surface area, and excellent loading capacity. However, the fabrication of polymer-based porous YSPs remains a great challenge. In this work, multifunctional polycaprolactone YSPs were produced using trineedle coaxial electrospraying with a simple nonsolvent process. TiO2-Ag nanoparticles and Ganoderma lucidum polysaccharides (GLPs) were encapsulated into the outer shell of the YSPs as the major antibacterial and antioxidant components, whereas iron oxide (Fe3O4) nanoparticles were incorporated into the inner core to act as a photothermal agent. The morphology and structure, chemical composition, biocompatibility, antioxidant, and antibacterial effects of the fabricated YSPs, photothermal effects, and the release profile of the encapsulated GLP were studied in vitro. Furthermore, the in vivo wound healing effects of the YSPs and the laser-assisted therapy were explored based on a burn wound model on c57 mice.

Synthesis of Mesoporous Co3O4/NiCo2O4 Nanorods and Their Electrochemical Study.

Mesoporous Co3O4/NiCo2O4 nanorods were obtained by a hydrothermal reaction with the assistance of Ni foam and subsequent annealing treatment. The characterization of this composition by X-ray diffraction, X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy, energy dispersive spectra and Brunauer-Emmett-Teller analysis revealed that the nanorods consisted of Co3O4 and NiCo2O4 phase, exhibiting high porosity and rich crystal defects. The electrochemical data showed a specific capacitance of 1173 mF cm-2 and 606 mF cm-2 at 2 mV s-1 and 1 mA cm-2, respectively. Its cycling performance was 83.9% at 3 mA cm-2 after 4000 cycles. Furthermore, the asymmetric supercapacitor Co3O4/NiCo2O4//AC delivered an energy density of 11.7 W h kg-1 and power density of 760 W kg-1.

Pharmacological effects of natural Ganoderma and its extracts on neurological diseases: A comprehensive review.

Ganoderma, has been used for clinical applications for thousands of years as a highly-nutritious and significantly-effective medicinal herb. The active components and efficacy of Ganoderma are constantly being explored and supplemented every year. In recent years, more and more literature has reported the pharmacological effects of Ganoderma on anti-tumor, liver protection and immunity enhancement, especially on neuroprotection. Numerous research works on the neuroprotective effects of Ganoderma have been documented (e.g., modulation of neurogenesis, amelioration of Alzheimer's disease, therapeutic effect on epilepsy, the protective effect on neural cells in stroke injury, etc.) thus it has drawn increasing attention. However, an integrated and comprehensive review of recent research findings has not been detailed in any great depth. Therefore, the purpose of this review is to summarize and elucidate recent progress of neuroprotective effects of natural Ganoderma and its extracts.

Targeting oxidative stress using tri-needle electrospray engineered Ganoderma lucidum polysaccharide-loaded porous yolk-shell particles.

Chronic lung diseases (e.g. chronic obstructive pulmonary disease and asthma) are associated with oxidative stress and common treatments include various types of inhalation therapies. In this work Ganoderma lucidum polysaccharide (GLP), a naturally occurring antioxidant is loaded into porous Poly (ε-caprolactone) (PCL) particles using a single step tri-needle coaxial electrospray process (Tri-needle CES); with a view to develop therapies to combat oxidative stress. Based on the core-shell structure of porous yolk shell particles (YSPs), GLP-loaded YSPs displayed a bi-phasic release pattern. In vitro cell studies indicate GLP-loaded porous YSPs display good biocompatibility and positive attributes towards H2O2-induced oxidative stress in MRC-5 cells and dramatically attenuate intracellular reactive oxygen species (ROS) levels as well as significantly increase cell viability. In vivo inhalation studies indicate that GLP-loaded porous YSPs can be delivered to deep lung tissue and remain deposited for over 48 h and are subsequently removed by natural clearance mechanisms. Based on current findings GLP-loaded porous YSPs are suitable for pulmonary delivery and display good inhalation therapy potential to treat chronic lung diseases.