64-fs L-band pulse generation by an all-fibre Er-doped laser

We demonstrate a L-band all-fibre erbium-doped laser mode-locked by nonlinear polarisation rotation. The use of a single gain segment with appropriate length and dispersion and a L-band optimised Brewster fibre grating as an in-fibre polariser enables the generation of 64-fs pulses at 1.59µm

Generation of 64-fs L-band stretched pulses from an all-fibre Er-doped laser

We demonstrate an L-band all-fibre erbium-doped laser mode locked by nonlinear polarisation rotation and working in the stretched-pulse regime. The use of a single segment of gain fibre with appropriate length and dispersion and a Brewster fibre grating optimised for the L band as an in-fibre polariser enables the generation of pulses at 1.59-μm central wavelength, which can be linearly compressed to 64-fs duration. Numerical simulations of the laser model support our experimental findings. Our laser design gives a route towards low-cost and low-complexity fibre-integrated laser sources for applications requiring L-band ultrashort pulses

The role of Akkermansia muciniphila in inflammatory bowel disease: Current knowledge and perspectives

Inflammatory bowel diseases, including Crohn’s disease and ulcerative colitis, is a chronic relapsing gastrointestinal inflammatory disease mediated by dysregulated immune responses to resident intestinal microbiota. Current conventional approaches including aminosalicylates, corticosteroids, immunosuppressive agents, and biological therapies are focused on reducing intestinal inflammation besides inducing and maintaining disease remission, and managing complications. However, these therapies are not curative and are associated with various limitations, such as drug resistance, low responsiveness and adverse events. Recent accumulated evidence has revealed the involvement of mucin-degrading bacterium Akkermansia muciniphila (A. muciniphila) in the regulation of host barrier function and immune response, and how reduced intestinal colonisation of probiotic A. muciniphila can contribute to the process and development of inflammatory bowel diseases, suggesting that it may be a potential target and promising strategy for the therapy of inflammatory bowel disease. In this review, we summarise the current knowledge of the role of A. muciniphila in IBD, especially focusing on the related mechanisms, as well as the strategies based on supplementation with A. muciniphila, probiotics and prebiotics, natural diets, drugs, and herbs to promote its colonisation in the gut, and holds promise for A. muciniphila-targeted and -based therapies in the treatment of inflammatory bowel disease

Repair of fingertip defect with reverse digital artery island flap and repair of donor site with digital dorsal advancement flap

ObjectiveThe reverse digital artery island flap (RDAF) is widely used in repairing fingertip skin defects based on its good appearance and practicability. However, the donor area of the flap needs skin grafting, which can lead to complications. This retrospective study explored the clinical application of digital dorsal advance flap (DDAF) in repairing the donor site of the reverse digital artery island flap.MethodFrom June 2019 to February 2022, 17 patients with a soft tissue defect of the finger had been restored with the reverse digital artery island flap, and at the same time, the donor area was repaired with digital dorsal advance flap (DDAF). The sensitivity, the active range of motion (ROM) and patient satisfaction were assessed after the operation.ResultsAll flaps survived completely without skin grafting with only one linear scar. The sensory and motor functions of all patients recovered well. Assessment based on the Michigan Hand Outcomes Questionnaire (MHQ) showed satisfactory functional recovery for all patients.ConclusionsReconstruction using RDAF combined with DDAF represents an effective alternative for repairing fingertip skin defects

Prodrug Strategy for PSMA-targeted Delivery of TGX-221 to Prostate Cancer Cells

TGX-221 is a potent, selective, and cell membrane permeable inhibitor of the PI3K p110β catalytic subunit. Recent studies showed that TGX-221 has anti-proliferative activity against PTEN-deficient tumor cell lines including prostate cancers. The objective of this study was to develop an encapsulation system for parenterally delivering TGX-221 to the target tissue through a prostate-specific membrane aptamer (PSMAa10) with little or no side effects. In this study, PEG-PCL micelles were formulated to encapsulate the drug, and a prodrug strategy was pursued to improve the stability of the carrier system. Fluorescence imaging studies demonstrated that the cellular uptake of both drug and nanoparticles were significantly improved by targeted micelles in a PSMA positive cell line. The area under the plasma concentration time curve of the micelle formulation in nude mice was 2.27-fold greater than the naked drug, and the drug clearance rate was 17.5-fold slower. These findings suggest a novel formulation approach for improving site-specific drug delivery of a molecular-targeted prostate cancer treatment

Study on Surface Discharge Characteristics of GO-Doped Epoxy Resin–LN2 Composite Insulation

Superconducting power lead equipment for epoxy insulation, such as high-temperature superconducting DC power or liquefied natural gas energy pipelines, as well as high-temperature superconducting cables, has long been used in extreme environments, from liquid nitrogen temperatures to normal temperatures. It is easy to induce surface discharge and flashover under the action of strong electric field, which accelerates the insulation failure of current leads. In this paper, two-dimensional nano-material GO was used to control the electrical properties of epoxy resins. The DC surface discharge and flashover characteristics of the prepared epoxy resin–GO composite insulation materials were tested at room temperature with liquid nitrogen. The surface discharge mechanism of the epoxy resin–GO composite insulation materials was analyzed. The experimental results show that the insulation properties of epoxy composites doped with GO changed. Among them, the surface flashover voltage of 0.05 wt% material is the best, which can inhibit the discharge phenomenon and improve its insulation properties in extreme environments, from room temperature to liquid nitrogen temperature. It is found that the development process of surface discharge of composite insulating materials under liquid nitrogen is quite different from that under room temperature. Before critical flashover, the repetition rate and amplitude of surface discharge remain at a low level until critical flashover. Furthermore, the voltage of the first flashover is significantly higher than that of the subsequent flashover under the action of the desorption gas on the surface of the composite insulating material and the gasification layer produced by the discharge. Given that the surface flashover voltage of 0.05 wt% epoxy composite is the best, the research and analysis of 0.05 wt% composite is emphasized. In the future design of superconducting power lead insulation, the modification method of adding GO to epoxy resin can be considered in order to improve its insulation performance

Study on surface discharge of nonlinear conductive epoxy resin/SrTiO3 composites in 80–300 K temperature zone

Abstract Bisphenol F epoxy resin (EP) is often used in terminal current lead insulation of superconducting equipment because of its good insulation performance, high mechanical strength, good toughness at cryogenic temperatures, and resistance to cold shock and heat shock. However, due to the wide temperature range of 80–300 K and the strong electric field, the EP‐N2 interface is prone to surface flashover, resulting in terminal insulation failure. To improve the reliability of the current lead insulation, non‐linear conductive EP/strontium titanate (SrTiO3) composites were prepared by modification with nano filling. The changes of dielectric, surface discharge, flashover, and trap distribution characteristics of composite materials were studied, and the mechanism of SrTiO3 on the surface flashover of composite materials was analysed. The results show that the conductivity of the composite increases with the rise of SrTiO3 filling content, and the amplitude of improvement is greater under the strong electric field, showing a more significant non‐linearity. The composite has a lower trap energy level and a greater number of shallow traps compared to pure EP, which accelerates surface charge de‐trapping and reduces charge accumulation, effectively enhancing the discharge and surface flashover voltage of the composite

Molecular Dynamics Simulation of Cracking Process of Bisphenol F Epoxy Resin under High-Energy Particle Impact

The current lead insulation of high-temperature superconductivity equipment is under the combined action of large temperature gradient field and strong electric field. Compared with a uniform temperature field, its electric field distortion is more serious, and it is easy to induce surface discharge to generate high-energy particles, destroy the insulation surface structure and accelerate insulation degradation. In this paper, the degradation reaction process of bisphenol F epoxy resin under the impact of high-energy particles, such as O3−, HO–, H3O+ and NO+, is calculated based on ReaxFF simulation. According to the different types of high-energy particles under different voltage polarities, the micro-degradation mechanism, pyrolysis degree and pyrolysis products of epoxy resin are analyzed. The results show that in addition to the chemical reaction of high-energy particles with epoxy resin, their kinetic energy will also destroy the molecular structure of the material, causing the cross-linked epoxy resin to pyrolyze, and the impact of positive particles has a more obvious impact on the pyrolysis of epoxy resin