Optical-Cavity-Incorporated Colorful All-Solid-State Electrochromic Devices for Dual Anti-Counterfeiting

The fusion of electrochromic technology with optical resonant cavities presents an intriguing innovation in the electrochromic field. However, this fusion is mainly achieved in liquid electrolyte-based or sol-gel electrolyte-based electrochromic devices, but not in all-solid-state electrochromic devices, which have broader industrial applications. Here, a new all-solid-state electrochromic device is demonstrated with a metal-dielectric-metal (MDM) resonant cavity, which can achieve strong thin-film interference effects through resonance, enabling the device to achieve unique structural colors that have rarely appeared in reported all-solid-state electrochromic devices, such as yellow green, purple, and light red. The color gamut of the device can be further expanded due to the adjustable optical constants of the electrochromic layer. What is more, this device exhibits remarkable cycling stability (maintaining 84% modulation capability after 7200 cycles), rapid switching time (coloration in 2.6 s and bleaching in 2.8 s), and excellent optical memory effect (only increasing by 13.8% after almost 36 000 s). In addition, this exquisite structural design has dual-responsive anti-counterfeiting effects based on voltage and angle, further demonstrating the powerful color modulation capability of this device.

[The mechanism of OC-STAMP overexpression induced actin cytoskeleton remodeling in promoting epithelial-mesenchymal transition in the alveolar type Ⅱ epithelial cell]

Objective: To explore the mechanism of osteoclast stimulatory transmembrane protein (OC-STAMP) overexpression on epithelial-mesenchymal transition (EMT) . Methods: In April 2021, mice alveolar type Ⅱ epithelial cells MLE-12 were divided into five groups: overexpression control group (NC group), Ocstamp overexpression group (over-Ocstamp group), Fasudil intervention group (over-Ocstamp+Fasudil group), silence control group (si-NC group), Ocstamp silence group (si-Ocstamp group). The protein expressions of OC-STAMP, epithelial marker protein-E-cadherin (E-cad), interstitial marker protein-α-smooth muscle actin (α-SMA), Ras homolog gene family member A (RhoA), Rho GDP dissociation inhibitor α (Rho GDIα), Rho-associated protein kinase (ROCK), phosphate myosin phosphatase (p-MYPT) were examined by Western blotting and Immunocytochemical staining. The filamentous actin (F-actin) was detected by Phalloidin method. t test was used to compare the relative expression of each protein between the two groups. Results: Western blotting and Immunocytochemical staining showed that compared with the NC group, the expression level of E-cad was down-regulated, while the expression levels of α-SMA, Rho GDIα, RhoA, ROCK, p-MYPT were increased, and F-actin expression was enhanced in the over-Ocstamp group. The differences were statistically significant (P<0.05). There were no significant differences in E-cad and α-SMA protein expression in si-Ocstamp group compared with si-NC group (P>0.05). Compared with over-Ocstamp group, the expression level of E-cad protein in over-Ocstamp+Fasudil group was up-regulated, the expression levels of α-SMA, Rho GDIα, RhoA, ROCK and p-MYPT protein were decreased, and F-actin expression was weakened, with statistical significance (P<0.05) . Conclusion: OC-STAMP overexpression in alveolar type Ⅱ epithelial cells may induce actin cytoskeleton remodeling through activation of Rho GDIα/RhoA/ROCK signaling pathway, thus promoting EMT.

Gender equity of authorship in pulmonary medicine over the past decade

BACKGROUND

Gender disparity in authorship broadly persists in medical literature, little is known about female authorship within pulmonary medicine.

METHODS

A bibliometric analysis of publications from 2012 to 2021 in 12 journals with the highest impact in pulmonary medicine was conducted. Only original research and review articles were included. Names of the first and last authors were extracted and their genders were identified using the Gender-API web. Female authorship was described by overall distribution and distribution by country/region/continent and journal. We compared the article citations by gender combinations, evaluated the trend in female authorship, and forecasted when parity for first and last authorship would be reached. We also conducted a systematic review of female authorship in clinical medicine.

RESULTS

14,875 articles were included, and the overall percentage of female first authors was higher than last authors (37.0% vs 22.2%, p<0.001). Asia had the lowest percentage of female first (27.6%) and last (15.2%) authors. The percentages of female first and last authors increased slightly over time, except for a rapid increase in the COVID-19 pandemic periods. Parity was predicted in 2046 for the first authors and 2059 for the last authors. Articles with male authors were cited more than articles with female authors. However, male-male collaborations significantly decreased, whereas female-female collaborations significantly increased.

CONCLUSIONS

Despite the slow improvement in female authorship over the past decade, there is still a substantial gender disparity in female first and last authorship in high-impact medical journals in pulmonary medicine.

Colorful Electrochromic Displays with High Visual Quality Based on Porous Metamaterials

The introduction of metamaterials into electrochromic (EC) displays has recently inspired a great breakthrough in the EC field, as this can offer a variety of new attractive features, from a very wide gamut of colors to very fast switching times. However, such metamaterial-based EC displays still face significant constraints when developing from single electrodes to full devices, because other supportive components in devices, such as counter electrodes and electrolytes, significantly affect light propagation and the subsequent perceived color quality in metamaterial-based EC devices. Herein, a new, cost-effective device design structured around a new type of porous metamaterial is reported to circumvent the critical problem in metamaterial-based EC displays. Owing to its unique design, the metamaterial-based EC device achieves good color quality with no drop in brightness or shift in color chromaticity when compared with a single electrode. Moreover, the porous-metamaterial-based EC device can exhibit non-iridescence and be viewed from a wide range of angles (5°-85°) and has fast switching response (2.4 and 2.5 s for coloration and bleaching, respectively), excellent cycling performance (at least 2000 cycles), and extremely low power consumption (4.0 mW cm^-2 ).

Engineering Structural Janus MXene-nanofibrils Aerogels for Season-Adaptive Radiative Thermal Regulation

Aerogels have provided a significant platform for passive radiation-enabled thermal regulation, arousing extensive interest due to their capabilities of radiative cooling or heating. However, there still remains challenge of developing functionally integrated aerogels for sustainable thermal regulation in both hot and cold environment. Here, Janus structured MXene-nanofibrils aerogel (JMNA) is rationally designed via a facile and efficient way. The achieved aerogel presents the characteristic of high porosity (≈98.2%), good mechanical strength (tensile stress of ≈2 MPa, compressive stress of ≈115 kPa), and macroscopic shaping property. Based on the asymmetric structure, the JMNA with switchable functional layers can alternatively enable passive radiative heating and cooling in winter and summer, respectively. As a proof of concept, JMNA can function as a switchable thermal-regulated roof to effectively enable the inner house model to maintain >25 °C in winter and <30 °C in hot summer. This design of Janus structured aerogels with compatible and expandable capabilities is promising to widely benefit the low-energy thermal regulation in changeable climate.

Two-Dimensional Molecular Sheets of Transition Metal Oxides toward Wearable Energy Storage

Flexible and wearable electronics have recently sparked intense interest in both academia and industry because they can greatly revolutionize human lives by impacting every aspect of our daily routine. Therefore, developing compatible energy storage devices has become one of the most important research frontiers in this field. Particularly, the development of flexible electrodes is of great significance when considering their essential role in the performance of these devices. Although there is no doubt that transition metal oxide nanomaterials are suitable for providing electrochemical energy storage, individual oxides generally cannot be developed into freestanding electrodes because of their intrinsically low mechanical strength.Two-dimensional sheets with genuine unilamellar thickness are perfect units for the assembly of freestanding and mechanically flexible devices, as they have the advantages of low thickness and good flexibility. Therefore, the development of metal oxide materials into a two-dimensional sheet morphology analogous to graphene is expected to solve the above-mentioned problems. In this Account, we summarize the recent progress on two-dimensional molecular sheets of transition metal oxides for wearable energy storage applications. We start with our understanding of the principle of producing two-dimensional metal oxides from their bulk-layered counterparts. The unique layered structure of the precursors inspired the exploration of their interlayer chemistry, which helps us to understand the processes of swelling and delamination. Rational methods for tuning the chemical composition, size/thickness, and surface chemistry of the obtained nanosheets and how physicochemical properties of the nanosheets can be modulated are then briefly introduced. Subsequently, the orientational alignment of the anisotropic sheets and the origins of their liquid-crystalline characteristics are discussed, which are of vital importance for their subsequent macroscopic assembly. Finally, macroscopic electrodes with geometric diversity ranging from one-dimensional macroscopic fibers to two-dimensional films/papers and three-dimensional monolithic foams are summarized. The intrinsically low mechanical stiffness of metal oxide sheets can be effectively overcome by wisely designing the assembly mode and sheet interfaces to obtain decent mechanical properties integrated with superior electrochemical performance, thereby providing critical advantages for the fabrication of wearable energy storage devices.We expect that this Account will stimulate further efforts toward fundamental research on interface engineering in metal oxide sheet assembly and facilitate wide applications of their designed assemblies in future new-concept energy conversion devices and beyond. In the foreseeable future, we believe that there will be a big explosion in the application of transition metal oxide sheets in flexible electronics.

Remarkable Near-Infrared Electrochromism in Tungsten Oxide Driven by Interlayer Water-Induced Battery-to-Pseudocapacitor Transition

Near-infrared (NIR) electrochromism is of academic and technological interest for a variety of applications in advanced solar heat regulation, photodynamic therapy, optical telecommunications, and military camouflage. However, inorganic materials with outstanding NIR modulation capability are quite few. Herein, we propose a promising strategy for achieving strong NIR electrochromism in tungsten oxide that is closely related to its electrochemical transformation from battery-type behavior to pseudocapacitance, induced by introducing an interlayer space with water molecules within tungsten oxide. Further evidence demonstrates that the interlayer water molecules significantly reduced the energy barrier to ion diffusion and increased the ion flux in tungsten oxide. As a result, compared with anhydrous WO₃, the as-synthesized WO₃·2H₂O nanoplates exhibited remarkably improved NIR electrochromic properties, including a large transmittance modulation (90.4%), high coloration efficiency (322.6 cm² C^-1), and high cyclic stability (maintaining 93.7% after 500 cycles), which were comparable to those of the best reported NIR electrochromic materials. Moreover, the application of the WO₃·2H₂O nanoplate-based electrochromic device resulted in a temperature difference of 11.9 °C, indicating good solar thermal regulation ability.

A Dopant Replacement-Driven Molten Salt Method toward the Synthesis of Sub-5-nm-Sized Ultrathin Nanowires

The high-temperature molten-salt method is an important inorganic synthetic route to a wide variety of morphological phenotypes. However, its utility is limited by the fact that it is typically incapable of producing ultrathin (<5 nm diameter) nanowires, which have a crucial role in novel nanotechnology applications. Herein, a rapid molten salt-based synthesis of sub-5-nm-sized nanowires of hexagonal tungsten oxide (h-WO₃ ) that is critically dependent on a substantial proportion of molybdenum (Mo) dopant is described. This dopant-driven morphological transition in tungsten oxide (WO₃ ) may be attributable to the collapse of layered structure, followed by nanocluster aggregation, coalescence, and recrystallization to form ultrathin nanowires. Interestingly, due to the structural properties of h-WO₃ , the thus-formed ultrathin nanowires are demonstrated to be excellent photocatalysts for the production of ammonia (NH₃ ) from nitrogen (N₂ ) and water. The ultrathin nanowires exhibit a high photocatalytic NH₃ -production activity with a rate of 370 µmol g^-1 h^-1 and an apparent quantum efficiency of 0.84% at 420 nm, which is more than twice that obtained from the best-performing Mo-doped W₁₈ O₄₉ nanowire catalysts. It is envisaged that the dopant replacement-driven synthetic protocol will allow for rapid access to a series of ultrathin nanostructures with intriguing properties and increase potential applications.

Surface-Modified Two-Dimensional Titanium Carbide Sheets for Intrinsic Vibrational Signal-Retained Surface-Enhanced Raman Scattering with Ultrahigh Uniformity

Surface-enhanced Raman scattering (SERS) employing a non-noble substrate in comparison with conventional noble-metal ones offers advantages of low cost and rich selection of candidates; however, its application has been seriously hindered by its unsatisfactory detection sensitivity, poor uniformity, and undesirable modification of vibrational signals via changing the orientation and/or polarizability of probe molecules. Here, an unusually sensitive but nonselective enhancement was achieved by employing titanium carbide sheets modified with aluminum oxyanions in situ as active supports for Raman measurement. The analyte molecules adopted a conformation similar to what they adopt on a bare substrate, while closely interacting with the aluminum oxyanion surface, which leads to the rare observation of highly sensitive but nonselective enhancement with a detection limit close to the pM level. With the substrate surface roughness in the nanometer region, an outstanding uniformity with a relative standard deviation of less than 4.3% was achieved. In addition, the SERS effect on the modified titanium carbide sheets was shown to be applicable to a wide range of analyte molecules, including both organic dyes and trace harmful compounds. The success of the work demonstrates the feasibility of surface tuning to improve the SERS effect, and it introduces a new window for two-dimensional materials in SERS applications.

Molecularly Thin Nitride Sheets Stabilized by Titanium Carbide as Efficient Bifunctional Electrocatalysts for Fiber-Shaped Rechargeable Zinc-Air Batteries

With the ever-increasing growth in next-generation flexible and wearable electronics, fiber-shaped zinc-air batteries have attracted considerable attention due to their advantages of high energy density and low cost, though their development, however, has been seriously hampered by the unavailability of efficient electrocatalysts. In this work, we designed a trimetallic nitride electrocatalyst in an unusual molecular sheet form, which was stabilized by metallic titanium carbide sheets. Besides the expected elevation in catalytic activity toward the oxygen evolution reaction, the material simultaneously unlocked excellent catalytic activity for oxygen reduction reaction with the half-wave potential as small as 0.84 V. A flexible fiber-shaped zinc-air battery, employing the designed electrocatalyst as the air cathode and a gel as the electrolyte, demonstrated an enhanced and durable electrochemical performance, outputting a competitive energy density of 627 Wh kg_zn^-1. This work opens new avenues for utilizing two-dimensional sheets in future wearable and portable device applications.

All Two-Dimensional Pseudocapacitive Sheet Materials for Flexible Asymmetric Solid-State Planar Microsupercapacitors with High Energy Density

With the rapid development of portable devices and wireless protocols, miniaturized energy storage units have become an important prerequisite. Although in-plane microsupercapacitors are emerging as competitive candidate devices, their practical applications have been severely hindered by their low energy density. Here, employing pseudocapacitive active materials working in complementary voltage windows, namely, manganese oxide (MnO₂) and titanium carbide (Ti₃C₂), both in the two-dimensional sheet morphology, a flexible asymmetric interdigitated solid-state microsupercapacitor was assembled. Profiting from the perfect voltage complementarity of the two types of sheets, the high exposure of electrochemically active sites and the maximized utilization of the sheets due to the planar ion transport, the designed device achieved excellent electrochemical performance even when using a gel electrolyte. In particular, the device obtained a high specific capacitance of 106 F g^-1 (295 mF cm^-2), a wide potential window (2 V), an ultrahigh rate performance (retaining 83% even with a 20-fold in current density to 20 A g^-1), an excellent cycling stability (87% retention after 10⁴ cycles at 10 A g^-1), and a competitive energy density of 58 W h kg^-1 (162 μW h cm^-2) that are even comparable to those of some microbatteries, while maintaining a high power density of 985 W kg^-1 (2.7 mW cm^-2). Importantly, this outstanding electrochemical performance was also stably maintained under various bending conditions. These results indicate that two-dimensional pseudocapacitive sheet materials have a plethora of possibilities for constructing flexible and wearable devices.

Towards full-colour tunability of inorganic electrochromic devices using ultracompact fabry-perot nanocavities

Intercalation-based inorganic materials that change their colours upon ion insertion/extraction lay an important foundation for existing electrochromic technology. However, using only such inorganic electrochromic materials, it is very difficult to achieve the utmost goal of full-colour tunability for future electrochromic technology mainly due to the absence of structural flexibility. Herein, we demonstrate an ultracompact asymmetric Fabry-Perot (F-P) nanocavity-type electrochromic device formed by using partially reflective metal tungsten as the current collector and reflector layer simultaneously; this approach enables fairly close matching of the reflections at both interfaces of the WO3 thin layer in device form, inducing a strong interference. Such an interference-enhanced device that is optically manipulated at the nanoscale displays various structural colours before coloration and, further, can change to other colours including blue, red, and yellow by changing the optical indexes (n, k) of the tungsten oxide layer through ion insertion.

Size-Independent Fast Ion Intercalation in Two-Dimensional Titania Nanosheets for Alkali-Metal-Ion Batteries

Compared to lithium ions, the fast redox intercalation of large-radius sodium or potassium ions into a solid lattice in non-aqueous electrolytes is an elusive goal. Herein, by regulating the interlayer structure of stacked titania sheets through weakened layer-to-layer interactions and a robustly pillared gallery space, the two-dimensional channel between neighboring sheets was completely open to guest intercalation, allowing fast intercalation that was practically irrespective of the carrier-ion sizes. Regardless of employing regular Li or large-radius Na and K ions, the material manifested zero strain-like behavior with no significant change in both host structure and interlayer space, enabling comparable capacities for all tested ions along with excellent rate behaviors and extraordinarily long lifetimes, even with 80-μm-thick electrodes. The result highlights the importance of interlayer structural features for unlocking the electrochemical activity of a layered material.

Rapid Magnetic 3D Printing of Cellular Structures with MCF-7 Cell Inks

A contactless label-free method using a diamagnetophoretic ink to rapidly print three-dimensional (3D) scaffold-free multicellular structures is described. The inks consist of MCF-7 cells that are suspended in a culture medium to which a paramagnetic salt, diethylenetriaminepentaacetic acid gadolinium (III) dihydrogen salt hydrate (Gd-DTPA), is added. When a magnetic field is applied, the host fluid containing the paramagnetic salt is attracted towards regions of high magnetic field gradient, displacing the ink towards regions with a low gradient. Using this method, 3D structures are printed on ultra-low attachment (ULA) surfaces. On a tissue culture treated (TCT) surface, a 3D printed spheroid coexists with a two-dimensional (2D) cell monolayer, where the composite is termed as a 2.5D structure. The 3D structures can be magnetically printed within 6 hours in a medium containing 25 mM Gd-DTPA. The influence of the paramagnetic salt on MCF-7 cell viability, cell morphology, and ability of cells to adhere to each other to stabilize the printed structures on both ULA and TCT surfaces is investigated. Gene expressions of hypoxia-inducible factor 1-alpha (HIF1α) and vascular endothelial growth factor (VEGF) allow comparison of the relative stresses for the printed 3D and 2.5D cell geometries with those for 3D spheroids formed without magnetic assistance. This magnetic printing method can be potentially scaled to a higher throughput to rapidly print cells into 3D heterogeneous cell structures with variable geometries with repeatable dimensions for applications such as tissue engineering and tumour formation for drug discovery.

Color-Changing Microfiber-Based Multifunctional Window Screen for Capture and Visualized Monitoring of NH3

Air pollution is one of the most serious issues affecting the world today. Instead of expensive and energy-intensive air filtering devices, a fiber-based transparent air filter coated on a window screen is seen as one of the state-of-the-art filtration technologies to combat the seriously growing problem, delivering the advantages of simplicity, convenience, and high filtering efficiency. However, such a window screen is currently limited to particulate matter (PM) filtration and ineffective with other air pollutants. Here, we report the use of a newfangled type of color-changing fibers, porous Prussian blue analogues (CuHCF)/polymer composite microfibers, for transparent window screens toward air pollutant filtration. To increase pollution filtration, pores and dimples are purposely introduced to the fibers using binary solvent systems through a nonsolvent-induced phase separation mechanism. Such composite microfibers overcome some of the limitations of those previously used fibers and could simultaneously capture PM_2.5, PM₁₀, and NH₃ with high efficiency. More interestingly, a distinct color change is observed upon exposure to air pollutants in such window screens, which provides multifunctional capability of simultaneous pollutant capture and naked eye screening of the pollutant amount. Specifically, in the case of long-term exposure to low-concentration NH₃, the symbol displayed in such window screens changes from yellow color to brown and the coloration rate is directly controlled by the NH₃ concentration, which may serve as a careful reminder for those people who are repeatedly exposed to low-concentration ammonia gas (referred to as chronic poisoning). In contrast, after short-term exposure to a high concentration of ammonia gas, the yellow symbol immediately becomes blackened, which provides timely information about the risk of acute ammonia poisoning or even ammonia explosion. Further spectroscopic results show that the chromatic behaviors in response to different concentrations of NH₃ are fundamentally different, which is related to the different locations of ammonia in the lattice of CuHCF, either in its interstitial sites or at the Fe(CN)₆ vacancy sites, largely distinguished by the absence or presence of atmospheric moisture.

Radially Aligned Hierarchical Nickel/Nickel-Iron (Oxy)hydroxide Nanotubes for Efficient Electrocatalytic Water Splitting

Designing well-controlled hierarchical structures on micrometer and nanometer scales represents one of the most important approaches for upgrading the catalytic abilities of electrocatalysts. Although NiFe (oxy)hydroxide has been widely studied as a water oxidation catalyst due to its high catalytic capability and abundance, its structural manipulation has been greatly restricted due to its inherent crystallographic stacking feature. In this work, we report for the first time the construction of a nanotube structure of NiFe (oxy)hydroxide with an inner Ni-rich layer, which was radially aligned on a macroporous nickel foam. Such a hierarchically structured material realized several crucial factors that are essential for excellent catalytic behaviors, including abundant catalytic sites, a high surface area, efficient ionic and electronic transport, etc., and the designed catalyst exhibited competitive electrocatalytic activity for reaction of not only oxygen evolution but also hydrogen evolution, which is very rare. As a result, this novel material was well-suited for the use as a bifunctional catalyst in an integrated water-splitting electrolyzer, which could be even driven by a single AA battery or a 1.5 V solar cell, outperforming a benchmark catalyst of noble-metal ruthenium-platinum combinations and most state-of-the-art electrocatalysts. The work provided important suggestions for the rational modulation of catalysts with new structures targeted for high-performance electrodes used in electrochemical applications.

MUC1- and Survivin-based DNA Vaccine Combining Immunoadjuvants CpG and interleukin-2 in a Bicistronic Expression Plasmid Generates Specific Immune Responses and Antitumour Effects in a Murine Colorectal Carcinoma Model

DNA vaccination is a promising cancer treatment due to its safety, but poor immunogenicity limits its application. However, immunoadjuvants, heterogeneous prime-boost strategies and combination with conventional treatments can be used to improve the antitumour immune effects. A CpG motif and interleukin-2 (IL-2) cytokine are often used as adjuvants. In this study, a DNA vaccine containing a CpG motif was constructed to evaluate its adjuvant effect. The results show that the cytotoxicity of the DNA vaccine was increased fivefold, and survival lifetime was prolonged twofold by the CpG motif adjuvant. To simplify the industrial production process, a bicistronic plasmid was constructed to carry the fusion genes of survivin/MUC1 (MS) and IL-2 and with a CpG motif in its backbone. The results showed that the antitumour effect of the bicistronic vaccine was the same as that of the two vaccine co-injected regime. Furthermore, the vaccine could suppress metastatic tumour foci by 69.1% in colorectal carcinoma-bearing mice. Moreover, the vaccine induced survivin- and MUC1-specific immune responses in splenocytes and induced the immune promoting factor CCL-19 and GM-CSF upregulated, while metastatic-associated factor MMP-9 and immunosuppressing factor PD-L1 downregulated in tumour tissue. When combining the vaccine with the chemotherapy drug oxaliplatin, the survival was prolonged by about 2.5-fold. In conclusion, the DNA vaccine containing a CpG motif in bicistronic form showed good effects on colorectal cancer by inhibiting both tumour growth and metastasis, and combination with oxaliplatin could improve its antitumour effects.

Semiconductor SERS enhancement enabled by oxygen incorporation

Semiconductor-based surface-enhanced Raman spectroscopy (SERS) substrates represent a new frontier in the field of SERS. However, the application of semiconductor materials as SERS substrates is still seriously impeded by their low SERS enhancement and inferior detection sensitivity, especially for non-metal-oxide semiconductor materials. Herein, we demonstrate a general oxygen incorporation-assisted strategy to magnify the semiconductor substrate–analyte molecule interaction, leading to significant increase in SERS enhancement for non-metal-oxide semiconductor materials. Oxygen incorporation in MoS₂ even with trace concentrations can not only increase enhancement factors by up to 100,000-fold compared with oxygen-unincorporated samples but also endow MoS₂ with low limit of detection below 10⁻⁷ M. Intriguingly, combined with the findings in previous studies, our present results indicate that both oxygen incorporation and extraction processes can result in SERS enhancement, probably due to the enhanced charge-transfer resonance as well as exciton resonance arising from the judicious control of oxygen admission in semiconductor substrate.

The application of non-metal-oxide semiconductor materials as surface-enhanced Raman spectroscopy (SERS) substrates is impeded by their low SERS enhancement and detection sensitivity. Here, the authors develop a general oxygen incorporation strategy to magnify these parameters.

Versatile Cutting Method for Producing Fluorescent Ultrasmall MXene Sheets

As a recently created inorganic nanosheet material, MXene has received growing attention and has become a hotspot of intensive research. The efficient morphology control of this class of material could bring enormous possibilities for creating marvelous properties and functions; however, this type of research is very scarce. In this work, we demonstrate a general and mild approach for creating ultrasmall MXenes by simultaneous intralayer cutting and interlayer delamination. Taking the most commonly studied Ti₃C₂ as an illustrative example, the resulting product possessed monolayer thickness with a lateral dimension of 2-8 nm and exhibited bright and tunable fluorescence. Further, the method could also be employed to synthesize ultrasmall sheets of other MXene phases, for example, Nb₂C or Ti₂C. Importantly, although the strong covalent M-C bond was to some extent broken, all of the characterizations suggested that the chemical structure was composed of well-maintained host layers without observation of any serious damages, demonstrating the superior reaction efficiencies and safeties of our methods. This work may provide a facile and general approach to modulate various nanoscale materials and could further stimulate the vast applications of MXene materials in many optical-related fields.

Electrostatic-Interaction-Assisted Construction of 3D Networks of Manganese Dioxide Nanosheets for Flexible High-Performance Solid-State Asymmetric Supercapacitors

A three-dimensional (3D) macroscopic network of manganese oxide (MnO₂) sheets was synthesized by an easily scalable solution approach, grafting the negatively charged surfaces of the MnO₂ sheets with an aniline monomer by electrostatic interactions followed by a quick chemical oxidizing polymerization reaction. The obtained structure possessed MnO₂ sheets interconnected with polyaniline chains, producing a 3D monolith rich in mesopores. The MnO₂ sheets had almost all their reactive centers exposed on the electrode surface, and combined with the electron transport highways provided by polyaniline and the shortened diffusion paths provided by the porous structure, the deliberately designed electrode achieved an excellent capacitance of 762 F g^-1 at a current of 1 A g^-1 and cycling performance with a capacity retention of 90% over 8000 cycles. Furthermore, a flexible asymmetric supercapacitor based on the constructed electrode and activated carbon serving as the positive and negative electrodes, respectively, was successfully fabricated, delivering a maximum energy density of 40.2 Wh kg^-1 (0.113 Wh cm^-2) and power density of 6227.0 W kg^-1 (17.44 W cm^-2) in a potential window of 0-1.7 V in a PVA/Na₂SO₄ gel electrolyte.

Flexible Lithium-Ion Fiber Battery by the Regular Stacking of Two-Dimensional Titanium Oxide Nanosheets Hybridized with Reduced Graphene Oxide

Increasing interest has recently been devoted to developing small, rapid, and portable electronic devices; thus, it is becoming critically important to provide matching light and flexible energy-storage systems to power them. To this end, compared with the inevitable drawbacks of being bulky, heavy, and rigid for traditional planar sandwiched structures, linear fiber-shaped lithium-ion batteries (LIB) have become increasingly important owing to their combined superiorities of miniaturization, adaptability, and weavability, the progress of which being heavily dependent on the development of new fiber-shaped electrodes. Here, we report a novel fiber battery electrode based on the most widely used LIB material, titanium oxide, which is processed into two-dimensional nanosheets and assembled into a macroscopic fiber by a scalable wet-spinning process. The titania sheets are regularly stacked and conformally hybridized in situ with reduced graphene oxide (rGO), thereby serving as efficient current collectors, which endows the novel fiber electrode with excellent integrated mechanical properties combined with superior battery performances in terms of linear densities, rate capabilities, and cyclic behaviors. The present study clearly demonstrates a new material-design paradigm toward novel fiber electrodes by assembling metal oxide nanosheets into an ordered macroscopic structure, which would represent the most-promising solution to advanced flexible energy-storage systems.

Coupling Molecularly Ultrathin Sheets of NiFe-Layered Double Hydroxide on NiCo2O4 Nanowire Arrays for Highly Efficient Overall Water-Splitting Activity

Developing efficient but nonprecious bifunctional electrocatalysts for overall water splitting in basic media has been the subject of intensive research focus with the increasing demand for clean and regenerated energy. Herein, we report on the synthesis of a novel hierarchical hybrid electrode, NiFe-layered double hydroxide molecularly ultrathin sheets grown on NiCo₂O₄ nanowire arrays assembled from thin platelets with nickel foam as the scaffold support, in which the catalytic metal sites are more accessible and active and most importantly strong chemical coupling exists at the interface, enabling superior catalytic power toward both oxygen evolution reaction (OER) and additionally hydrogen evolution reaction (HER) in the same alkaline KOH electrolyte. The behavior ranks top-class compared with documented non-noble HER and OER electrocatalysts and even comparable to state-of-the-art noble-metal electrocatalysts, Pt and RuO₂. When fabricated as an integrated alkaline water electrolyzer, the designed electrode can deliver a current density of 10 mA cm^-2 at a fairly low cell voltage of 1.60 V, promising the material as efficient bifunctional catalysts toward whole cell water splitting.

Rapid Synthesis of Sub-5 nm Sized Cubic Boron Nitride Nanocrystals with High-Piezoelectric Behavior via Electrochemical Shock

A key challenge in current superhard materials research is the design of novel superhard nanocrystals (NCs) whereby new and unexpected properties may be predicted. Cubic boron nitride (c-BN) is a superhard material which ranks next to diamond; however, downsizing c-BN material below the 10 nm scale is rather challenging, and the interesting new properties of c-BN NCs remain unexplored and wide open. Herein we report an electrochemical shock method to prepare uniform c-BN NCs with a lateral size of only 3.4 ± 0.6 nm and a thickness of only 0.74 ± 0.3 nm at ambient temperature and pressure. The fabrication process is simple and fast, with c-BN NCs produced in just a few minutes. Most interestingly, the NCs exhibit excellent piezoelectric performance with a large recordable piezoelectric coefficient of 25.7 pC/N, which is almost 6 times larger than that from bulk c-BN and even competitive to conventional piezoelectric materials. The phenomenon of enhancement in the piezoelectric properties of BN NCs might arise from the nanoscale surface effect and nanoscale shape effect of BN NCs. This work paves an interesting route for exploring new properties of superhard NCs.

Tungsten Oxide Materials for Optoelectronic Applications

Tungsten oxide is a versatile transition-metal oxide with a vast number of polymorphs and sub-stoichiometric compositions, featuring innate tunnels and oxygen vacancies. The structure-determined nature, such as altered optical absorption and metal-like conductivity, makes tungsten oxide an attractive candidate for optoelectronic applications. A brief summary of the recent progress in tungsten oxide for optoelectronic applications is provided, including not only the traditional field of electrochromism/photochromism, but also new areas of application, such as visible-light-driven photocatalysis, photothermal therapy, and surface enhanced Raman spectroscopy (SERS). Also, the prospects for future applications of tungsten oxide are summarized and highlighted.

Organic-Base-Driven Intercalation and Delamination for the Production of Functionalized Titanium Carbide Nanosheets with Superior Photothermal Therapeutic Performance

The delamination of titanium carbide sheets, an intriguing class of two-dimensional materials, has been critically dependent on the extraction of interlayer Al in acidic media, such as concentrated hydrofluoric acid (HF) or a mixture of hydrochloric acid (HCl) and a fluoride salt. Herein, we report an organic-base-driven intercalation and delamination of titanium carbide that takes advantage of the amphoteric nature of interlayer Al. The resulting aluminum-oxoanion-functionalized titanium carbide sheets manifested unusually strong optical absorption in the near-infrared (NIR) region with a mass extinction coefficient as high as 29.1 L g^-1  cm^-1 at 808 nm. Thus, the performance of this material is comparable or even superior to that of state-of-the-art photoabsorption materials, including gold-based nanostructures, carbon-based materials, and transition-metal dichalcogenides. Preliminary studies show that the titanium carbide sheets serve as efficient photothermal agents against tumor cells.

The nature of anhedonia and avolition in patients with first-episode schizophrenia

BACKGROUND

Patients with schizophrenia have intact ability to experience emotion, but empirical evidence suggests that they fail to translate emotional salience into effortful behaviour. Previous research in patients with chronic schizophrenia suggests that working memory is important in integrating emotion and behaviour. This study aimed to examine avolition and anhedonia in patients with first-episode schizophrenia and clarify the role of working memory in emotion-behaviour coupling.

METHOD

We recruited 72 participants with first-episode schizophrenia and 61 healthy controls, and used a validated emotion-inducing behavioural paradigm to measure participants' affective experiences and how experienced emotion coupled with behaviour. Participants were given the opportunity to expend effort to increase or decrease their exposure to emotion-inducing photographs. Participants with schizophrenia having poor working memory were compared with those with intact working memory in their liking and emotion-behaviour coupling.

RESULTS

Patients with first-episode schizophrenia experienced intact 'in-the-moment' emotion, but their emotion was less predictive of the effort expended, compared with controls. The emotion-behaviour coupling was significantly weaker in patients with schizophrenia with poor working memory than in those with intact working memory. However, compared with controls, patients with intact working also showed substantial emotion-behaviour decoupling.

CONCLUSIONS

Our findings provide strong evidence for emotion-behaviour decoupling in first-episode schizophrenia. Although working memory deficits contribute to defective translation of liking into effortful behaviour, schizophrenia alone affects emotion-behaviour coupling.

Fast preparation of ultrafine monolayered transition-metal dichalcogenide quantum dots using electrochemical shock for explosive detection

A simple, general and fast method called “electrochemical shock” is developed to prepare monolayered transition-metal dichalcogenide (TMD) QDs with an average size of 2–4 nm and an average thickness of 0.85 ± 0.5 nm with only about 10 min of ultrasonication.

W18O49nanowire composites as novel barrier layers for Li–S batteries based on high loading of commercial micro-sized sulfur

A novel barrier layer material, nonstoichiometric W₁₈O₄₉nanowire is reported to alleviate the undesirable shuttle effect, thereby largely boosting the specific capacity and cyclability of Li–S batteries.

Facile synthesis of α-Fe2O3 nanodisk with superior photocatalytic performance and mechanism insight

Intrinsic short hole diffusion length is a well-known problem for α-Fe₂O₃ as a visible-light photocatalytic material. In this paper, a nanodisk morphology was designed to remarkably enhance separation of electron-hole pairs of α-Fe₂O₃. As expected, α-Fe₂O₃ nanodisks presented superior photocatalytic activity toward methylene blue degradation: more than 90% of the dye could be photodegraded within 30 min in comparison with a degradation efficiency of 50% for conventional Fe₂O₃ powder. The unique multilayer structure is thought to play a key role in the remarkably improved photocatalytic performance. Further experiments involving mechanism investigations revealed that instead of high surface area, ·OH plays a crucial role in methylene blue degradation and that O^·2- may also contribute effectively to the degradation process. This paper demonstrates a facile and energy-saving route to fabricating homogenous α-Fe₂O₃ nanodisks with superior photocatalytic activity that is suitable for the treatment of contaminated water and that meets the requirement of mass production.

Synergy of W18O49 and polyaniline for smart supercapacitor electrode integrated with energy level indicating functionality

Supercapacitors are important energy storage technologies in fields such as fuel-efficient transport and renewable energy. State-of-the-art supercapacitors are capable of supplanting conventional batteries in real applications, and supercapacitors with novel features and functionalities have been sought for years. Herein, we report the realization of a new concept, a smart supercapacitor, which functions as a normal supercapacitor in energy storage and also communicates the level of stored energy through multiple-stage pattern indications integrated into the device. The metal-oxide W18O49 and polyaniline constitute the pattern and background, respectively. Both materials possess excellent electrochemical and electrochromic behaviors and operate in different potential windows, -0.5-0 V (W18O49) and 0-0.8 V (polyaniline). The intricate cooperation of the two materials enables the supercapacitor to work in a widened, 1.3 V window while displaying variations in color schemes depending on the level of energy storage. We believe that our success in integrating this new functionality into a supercapacitor may open the door to significant opportunities in the development of future supercapacitors with imaginative and humanization features.

Anion-exchangeable layered materials based on rare-earth phosphors: unique combination of rare-earth host and exchangeable anions

Layered materials, three-dimensional crystals built from stacking two-dimensional components, are attracting intense interest because of their structural anisotropy and the fascinating properties that result. However, the range of such layered materials that can exchange anions is quite small. Continuing efforts have been underway to identify a new class of anion-exchangeable materials. One major goal is the incorporation of rare-earth elements within the host because researchers expect that the marriage of rare-earth skeleton host and the exchangeable species within the interlayer will open up new avenues both for the assembly of layered materials and for the understanding of rare-earth element chemistry. Such lanthanide layered solids have industrial potential. These materials are also of academic importance, serving as an ideal model for studying the cationic size effect on structure stability associated with lanthanide contraction. In this Account, we present the work done by ourselves and others on this novel class of materials. We examine the following four subtopics regarding these layered anionic materials: (1) synthesis strategy and composition diversity, (2) structural features, (3) structure stability with relative humidity, and (4) applications. These materials can be synthesized either by hydrothermal reactions or by homogeneous precipitation, and a variety of anions can be intercalated into the gallery. Although only cations with a suitable size can form the layered structure, the possible range is wide, from early to late lanthanides. We illustrate the effect of lanthanide contraction on properties including morphology, lattice dimensions, and coordination numbers. Because each lanthanide metal ion coordinates water molecules, and the water molecules point directly into the gallery space, this feature plays a critical role in stabilizing the layered structure. In the 9-fold monocapped square antiprism structure, the humidity-triggered transition between high- and low-hydrated phases corresponds to the uptake of H(2)O molecules at the capping site, which provides further evidence of the importance of water coordination. Applications using this unique combination of rare-earth element chemistry and layered materials include ion-exchange, photoluminescence, catalysis, and biomedical devices. Further exploration of the compounds and new methods for functional modification would dramatically enrich the junction of these two fields, leading to a new generation of layered materials with desirable properties.