Antimony-assisted controlled growth of PtSe2ribbon arrays for enhanced hydrogen evolution reaction.

In this study, we report the successful synthesis of few-layer parallel PtSe2ribbons on an Au foil employing a surface melting strategyviathe chemical vapor deposition growth method at 650 °C. The controlled formation of parallel ribbons was directed by the Au steps generated through antimony treatment. These ribbons exhibit an average length of exceeding 100µm and a width of approximately 100 nm across a substantial area. Electrocatalysis measurements showcase the catalytic performance of PtSe2ribbons grown on Au foil, which can be further augmented through subsequent oxidation treatment. This investigation introduces an effective growth method for few-layer ribbons at low temperatures and broadens the scope of employing the substrate-guided strategies for the synthesis of one-dimensional materials. Additionally, it underscores the potential of PtSe2ribbons as an electrocatalyst for hydrogen evolution.

Resolidified Chalcogen Precursors for High-Quality 2D Semiconductor Growth.

Two-dimensional (2D) semiconductors including transition metal dichalcogenides (TMDCs) have gained attention in optoelectronics for their extraordinary properties. However, the large amount and locally distributed lattice defects affect the optical properties of 2D TMDCs, and the defects originate from unstable factors in the synthesis process. In this work, we develop a method of pre-melting and resolidification of chalcogen precursors (sulfur and selenium), namely resolidified chalcogen, as precursor for the chemical vapor deposition growth of TMDCs with ultrahigh quality and uniformity. Taking WS2 as an example, the monolayer WS2 shows uniform fluorescence intensity and a small full-width at half-maximum of photoluminescence peak at low temperatures with an average value of 13.6±1.9 meV. The defect densities at the interior and edge region are both low and comparable, i.e., (9±3)×1012  cm-2 and (10±4)×1012  cm-2 , indicating its high structural quality and uniformity. This method is universal in growing high quality monolayer MoS2 , WSe2 , MoSe2 , and will benefit their applications.

Blown-Bubble Assembly and in Situ Fabrication of Sausage-like Graphene Nanotubes Containing Copper Nanoblocks.

We use a blown-bubble method to assemble Cu nanowires and in situ fabricate graphene-based one-dimensional heterostructures, including versatile sausage-like configurations consisting of multilayer graphene nanotubes (GNTs) filled by single or periodically arranged Cu nanoblocks (CuNBs). This is done by first assembling Cu nanowires among a polymer-based blown-bubble film (BBF) and then growing graphene onto the nanowire substrate using the polymer matrix as a solid carbon source by chemical-vapor deposition. The formation of sausage-like GNT@CuNB nanostructures is due to the partial melting and breaking of embedded Cu nanowires during graphene growth, which is uniquely related to our BBF process. We show that the GNT skin significantly slows the oxidation process of CuNBs compared with that of bare Cu nanowires, and the presence of stuffed CuNBs also reduces the linear resistance along the GNTs. The large-scale assembled graphene-based heterostructures achieved by our BBF method may have potential applications in heterojunction electronic devices and high-stability transparent conductive electrodes.

Washed microbiota transplantation combined with biological agents promotes histological remission in refractory severe ulcerative colitis with recurrent intestinal infection: A case report.

Ulcerative colitis (UC) is a chronic non-specific colitis disease. In recent years, fecal microbiota transplantation (FMT), including improved washed microbiota transplantation (WMT), and biological agents have helped improve the prognosis of patients with UC. However, a significant number of patients with moderate to severe UC do not get relief from glucocorticoids, immunosuppressants, and TNF-α antagonists. Patients with severe UC are frequently burdened with opportunistic infections and subsequent surgical interventions. Combined treatment modalities are crucial for patients with severe UC and opportunistic infections. Herein, we reported a case of a 25-year-old female with refractory severe UC complicated with recurrent Clostridioides difficile infection and recurrent cytomegalovirus infection for six years. Surgical removal of the affected bowel segment was almost unavoidable. She showed endoscopic and histological recovery after comprehensive WMT and Vedolizumab treatment. The following are our learnings from the case: 1. A combination of WMT and biological agents can potentially obviate the necessity for surgical treatment in patients with refractory severe UC and promote histological remission. 2. Personalized comprehensive treatment and chronic disease management models for patients with UC should be emphasized. 3. WMT can help treat opportunistic infections, which may also strengthen the treatment with gut-targeted biological agents when traditional TNF-α antagonists show poor efficacy.

Light-Driven Ionic and Molecular Transport through Atomically Thin Single Nanopores in MoS2/WS2 Heterobilayers.

Nanofluidic ionic and molecular transport through atomically thin nanopore membranes attracts broad research interest from both scientific and industrial communities for environmental, healthcare, and energy-related technologies. To mimic the biological ion pumping functions, recently, light-induced and quantum effect-facilitated charge separation in heterogeneous 2D-material assemblies is proposed as the fourth type of driving force to achieve active and noninvasive transport of ionic species through synthetic membrane materials. However, to date, engineering versatile van der Waals heterostructures into 2D nanopore membranes remains largely unexplored. Herein, we fabricate single nanopores in heterobilayer transition metal dichalcogenide membranes with helium ion beam irradiation and demonstrate the light-driven ionic transport and molecular translocation phenomena through the atomically thin nanopores. Experimental and simulation results further elucidate the driving mechanism as the photoinduced near-pore electric potential difference due to type II band alignment of the semiconducting WS2 and MoS2 monolayers. The strength of the photoinduced localized electric field near the pore region can be approximately 1.5 times stronger than that of its counterpart under the conventional voltage-driven mode. Consequently, the light-driven mode offers better spatial resolution for single-molecule detection. Light-driven ionic and molecular transport through nanopores in van der Waals heterojunction membranes anticipates transformative working principles for next-generation biomolecular sequencing and gives rise to fascinating opportunities for light-to-chemical energy harvesting nanosystems.

Highly sensitive biosensors for real-time monitoring of histamine at acupoint PC6 in rats based on graphene-modified acupuncture needles.

Acupoints are the local initial response sites of acupuncture therapeutic effects. As a biomarker, histamine is released into the acupoint region and plays its role concurrently as acupuncture needles are inserted into acupoints. Hence, real-time monitoring of histamine at acupoints is important to elucidate the effectiveness of the acupoint-activation process in acupuncture. Therefore, we developed highly sensitive acupuncture/Au particles/graphene biosensors by electrodeposition, brushing, and annealing methods based on bare acupuncture needles. We achieved a histamine detection limit of approximately 4.352 (±3.419) × 10-12 mol L-1 and good sensitivity of approximately 6.296 (±3.873) µA µM-1, with satisfactory specificity, repeatability, and stability in vitro, rendering them more competitive and suitable for real-time monitoring in vivo without causing additional damage. Subsequently, we conducted real-time histamine monitoring at non-acupoint and acupoint PC6 in rats, respectively. Our results showed minimal changes at the non-acupoint, whereas a trend of initial increase followed by a decrease was observed at acupoint PC6. The change in histamine concentration at acupoint PC6 reflected its involvement in the acupoint-activation procedure. Moreover, its peak position at ∼18 min could provide guidance for optimizing needle retaining time for maximum therapeutic effect. This work presents the first real-time in vivo monitoring of histamine at acupoints with high sensitivity and underscores the specificity of histamine release between non-acupoint and acupoint PC6, demonstrating great potential for elucidating the acupoint-activation mechanisms in acupuncture. Additionally, this work expands the application of nanomaterials in the integration of medicine and engineering, which is an important aspect of the future development of materials science.

Scalable Production of 2D Minerals by Polymer Intercalation and Adhesion for Multifunctional Applications.

Natural and sustainable 2D minerals have many unique properties and may reduce reliance on petroleum-based products. However, the large-scale production of 2D minerals remains challenging. Herein, a green, scalable, and universal polymer intercalation and adhesion exfoliation (PIAE) method to produce 2D minerals such as vermiculite, mica, nontronite, and montmorillonite with large lateral sizes and high efficiency, is developed. The exfoliation relies on the dual functions of polymers involving intercalation and adhesion to expand interlayer space and weaken interlayer interactions of minerals, facilitating their exfoliation. Taking vermiculite as an example, the PIAE produces 2D vermiculite with an average lateral size of 1.83 ± 0.48 µm and thickness of 2.40 ± 0.77 nm at a yield of ≈30.8%, surpassing state-of-the-art methods in preparing 2D minerals. Flexible films are directly fabricated by the 2D vermiculite/polymer dispersion, exhibiting outstanding performances including mechanical strength, thermal resistance, ultraviolet shielding, and recyclability. The representative application of colorful multifunctional window coatings in sustainable buildings is demonstrated, indicating the potential of massively produced 2D minerals.

Carrier Trapping in Wrinkled 2D Monolayer MoS2 for Ultrathin Memory.

Atomically thin two-dimensional (2D) semiconductors are promising for next-generation memory to meet the scaling down of semiconductor industry. However, the controllability of carrier trapping status, which is the key figure of merit for memory devices, still halts the application of 2D semiconductor-based memory. Here, we introduce a scheme for 2D material based memory using wrinkles in monolayer 2D semiconductors as controllable carrier trapping centers. Memory devices based on wrinkled monolayer MoS2 show multilevel storage capability, an on/off ratio of 106, and a retention time of >104 s, as well as tunable linear and exponential behaviors at the stimulation of different gate voltages. We also reveal an interesting wrinkle-based carrier trapping mechanism by using conductive atomic force microscopy. This work offers a configuration to control carriers in ultrathin memory devices and for in-memory calculations.

Fecal Microbiota Transplantation Combined with a Low FODMAP Diet for the Treatment of Irritable Bowel Syndrome with Predominant Diarrhea.

Background: Fecal microbiota transplantation (FMT) has been found to be effective in irritable bowel syndrome with predominant diarrhea (IBS-D). We conducted this study to determine the impact of a low FODMAP diet (LFD) on the gut microbiota and the efficacy of FMT in the treatment of IBS-D. Methods: A retrospective analysis of a single-arm open-label prospective study was conducted to investigate the impact of FMT alone (n = 40) and FMT+LFD (n = 40) in refractory IBS-D. The IBS-quality of life (QOL), IBS-severity scoring system (SSS), gastrointestinal symptom rating scale (GSRS), Hamilton anxiety scale (HAMA), and Hamilton depression scale (HAMD) were used to evaluate the efficacy, and partial 16S rDNA amplicon sequencing was used to profile the microbiota. Results: The response rates were higher in the FMT+LFD group than in the FMT group (1 mo, 3 mo, 6 mo: 70.0% vs. 55.0%, 67.5% vs. 57.5%, 62.5% vs. 27.5%, respectively). The FMT+LFD group showed significantly better improvement in IBS-QOL at 1, 3, and 6 months; IBS-SSS at 6 months; and GSRS at 1 month compared to FMT alone. Changes in HAMA and HAMD were similar in the two groups. The LFD significantly upregulated the FMT-induced microbial diversity (OTUs: 666 vs. 574, Adonis: P = 0.02) and significantly strengthened the upregulation of Bacteroides, Alistipes, and Ruminococcaceae_UCG-002 and the downregulation of Bifidobacterium. Conclusion: An LFD enhanced the efficacy of FMT, increased the gut microbial diversity after FMT, and strengthened the inhibitory effect of FMT on conditional pathogens.

High-throughput production of cheap mineral-based two-dimensional electrocatalysts for high-current-density hydrogen evolution.

The high-throughput scalable production of cheap, efficient and durable electrocatalysts that work well at high current densities demanded by industry is a great challenge for the large-scale implementation of electrochemical technologies. Here we report the production of a two-dimensional molybdenum disulfide-based ink-type electrocatalyst by a scalable exfoliation technique followed by a thermal treatment. The catalyst delivers a high current density of 1000 mA cm-2 at an overpotential of 412 mV for the hydrogen evolution. Using the same method, we produce a cheap mineral-based catalyst possessing excellent performance for high-current-density hydrogen evolution. Noteworthy, production rate of this catalyst is one to two orders of magnitude higher than those previously reported, and price of the mineral is five orders of magnitude lower than commercial Pt electrocatalysts. These advantages indicate the huge potentials of this method and of mineral-based cheap and abundant natural resources as catalysts in the electrochemical industry.

Single Carbon Fibers with a Macroscopic-Thickness, 3D Highly Porous Carbon Nanotube Coating.

Carbon fiber (CF) grafted with a layer of carbon nanotubes (CNTs) plays an important role in composite materials and other fields; to date, the applications of CNTs@CF multiscale fibers are severely hindered by the limited amount of CNTs grafted on individual CFs and the weak interfacial binding force. Here, monolithic CNTs@CF fibers consisting of a 3D highly porous CNT sponge layer with macroscopic-thickness (up to several millimeters), which is directly grown on a single CF, are fabricated. Mechanical tests reveal high sponge-CF interfacial strength owing to the presence of a thin transitional layer, which completely inhibits the CF slippage from the matrix upon fracture in CNTs@CF fiber-epoxy composites. The porous conductive CNTs@CF hybrid fibers also act as a template for introducing active materials (pseudopolymers and oxides), and a solid-state fiber-shaped supercapacitor and a fiber-type lithium-ion battery with high performances are demonstrated. These CNTs@CF fibers with macroscopic CNT layer thickness have many potential applications in areas such as hierarchically reinforced composites and flexible energy-storage textiles.

Graphene Oxide Glue-Electrode for Fabrication of Vertical, Elastic, Conductive Columns.

Graphene has a planar atomic structure with high flexibility and might be used as ultrathin conductive glues or adhesion layers in electronics and other applications. Here, we show that graphene oxide (GO) sheets condensed from solution can act as a pure, thin-layer, nonpenetrating glue for fabrication of vertical architectures anchored on rigid and flexible substrates. Carbon nanotube (CNT) sponges are used as a porous template to make polymer-reinforced composite columns, to achieve both high conductivity and elastic behavior. These vertical columns are fixed on a substrate by reduced GO sheets as an electrode and exhibit reversible resistance change under large-strain compression for many cycles. Similar to the CNT gecko feet, we disclose high adhesion forces at the CNT-GO and GO-SiO2 interfaces by mechanical tests and theoretical calculation. Three-dimensional CNT, graphene, and nanowire networks with our GO glue-electrodes have potential applications as energy storage electrodes, flexible sensors, functional composites, and vertical interconnects.

MOF-Derived ZnO Nanoparticles Covered by N-Doped Carbon Layers and Hybridized on Carbon Nanotubes for Lithium-Ion Battery Anodes.

Metal-organic frameworks (MOFs) have many promising applications in energy and environmental areas such as gas separation, catalysis, supercapacitors, and batteries; the key toward those applications is controlled pyrolysis which can tailor the porous structure, improve electrical conductivity, and expose metal ions in MOFs. Here, we present a systematic study on the structural evolution of zeolitic imidazolate frameworks hybridized on carbon nanotubes (CNTs) during the carbonization process. We show that a number of typical products can be obtained, depending on the annealing time, including (1) CNTs wrapped by relatively thick carbon layers, (2) CNTs grafted by ZnO nanoparticles which are covered by thin nitrogen-doped carbon layers, and (3) CNTs grafted by aggregated ZnO nanoparticles. We also investigated the electrochemical properties of those hybrid structures as freestanding membrane electrodes for lithium ion batteries, and the second one (CNT-supported ZnO covered by N-doped carbon) shows the best performance with a high specific capacity (850 mA h/g at a current density of 100 mA/g) and excellent cycling stability. Our results indicate that tailoring and optimizing the MOF-CNT hybrid structure is essential for developing high-performance energy storage systems.

Controlled Synthesis of Core-Shell Carbon@MoS2 Nanotube Sponges as High-Performance Battery Electrodes.

Heterogeneous inorganic nanotube structures consisting of multiwalled carbon nanotubes coated by long, continuous MoS2 sheets with tunable sheet number are synthesized using a carbon-nanotube sponge as a template. The resulting 3D porous hybrid sponges have potential applications as high-performance freestanding anodes for Li-ion batteries with excellent specific capacity and cycling stability.

Blown Bubble Assembly of Graphene Oxide Patches for Transparent Electrodes in Carbon-Silicon Solar Cells.

Graphene oxide (GO) sheets have a strong tendency to aggregate, and their interfaces can impose limitations on the electrical conductivity, which would hinder practical applications. Here, we present a blown bubble film method to assemble GO sheets with a uniform distribution over a large area and further interconnect individual GO sheets by transforming the bubble film into graphitized carbon. A conventional polymer was used to facilitate the bubble blowing process and disperse GO sheets in the bubble. Then, the bubble film was annealed on a Cu substrate, resulting in a highly transparent reduced GO (RGO)-carbon hybrid structure consisting of RGO patches well adhered to the carbon film. We fabricated RGO-carbon/Si solar cells with power conversion efficiencies up to 6.42%, and the assembled RGO patches hybridized with carbon film can form an effective junction with Si, indicating potential applications in thin film electronic devices and photovoltaics.

Comparison of Nanocarbon-Silicon Solar Cells with Nanotube-Si or Graphene-Si Contact.

Nanocarbon structures such as carbon nanotubes (CNTs) and graphene (G) have been combined with crystalline silicon wafers to fabricate nanocarbon-Si solar cells. Here, we show that the contact between the nanocarbon and Si plays an important role in the solar cell performance. An asymmetrically configured CNT-G composite film was used to create either CNT-Si dominating or G-Si dominating junctions, resulting in obviously different solar cell behavior in pristine state. Typically, solar cells with direct G-Si contacts (versus CNT-Si) exhibit better characteristics due to improved junction quality and larger contact area. On the basis of the composite film, the obtained CNT-G-Si solar cells reach power conversion efficiencies of 14.88% under air mass 1.5, 88 mW/cm2 illumination through established techniques such as acid doping and colloidal antireflection. Engineering the nanocarbon-Si contact is therefore a possible route for further improving the performance of this type of solar cells.