Liver fibrosis is a reversible wound-healing process aimed at maintaining organ integrity, and presents as the critical pre-stage of liver cirrhosis, which will eventually progress to hepatocellular ...carcinoma in the absence of liver transplantation. Fibrosis generally results from chronic hepatic injury caused by various factors, mainly viral infection, schistosomiasis, and alcoholism; however, the exact pathological mechanisms are still unknown. Although numerous drugs have been shown to have antifibrotic activity in vitro and in animal models, none of these drugs have been shown to be efficacious in the clinic. Importantly, hepatic stellate cells(HSCs) play a key role in the initiation, progression, and regression of liver fibrosis by secreting fibrogenic factors that encourage portal fibrocytes, fibroblasts, and bone marrow-derived myofibroblasts to produce collagen and thereby propagate fibrosis. These cells are subject to intricate cross-talk with adjacent cells, resulting in scarring and subsequent liver damage. Thus, an understanding of the molecular mechanisms of liver fibrosis and their relationships with HSCs is essential for the discovery of new therapeutic targets. This comprehensive review outlines the role of HSCs in liver fibrosis and details novel strategies to suppress HSC activity, thereby providing new insights into potential treatments for liver fibrosis.
The exact nondipole Volkov solutions to the Schrödinger equation and Pauli equation are found, based on which a strong field theory beyond the dipole approximation is built for describing the ...nondipole effects in nonrelativistic laser driven electron dynamics. This theory is applied to investigate momentum partition laws for multiphoton and tunneling ionization and explicitly shows that the complex interplay of a laser field and Coulomb action may reverse the expected photoelectron momentum along the laser propagation direction. The magnetic-spin coupling does not bring observable effects on the photoelectron momentum distribution and can be neglected. Compared to the strong field approximation within the dipole approximation, this theory works in a much wider range of laser parameters and lays a solid foundation for describing nonrelativistic electron dynamics in both short wavelength and midinfrared regimes where nondipole effects are unavoidable.
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Silver nanowires (AgNWs) have attracted considerable attention as the material for emerging flexible, high conductive, and transparent wearable healthcare monitoring. However, due to the high ...possibility of AgNWs being oxidized in air and the discomfort caused by direct contact between silver nanowires and human skin, there are still some concerns to be taken into account in the direct application of AgNWs to ECG electrodes. Here, we combined AgNWs with graphene oxide (GO), and adopted the screen-printing technology for the fabrication of AgNWs/GO hybrid transparent conductive electrodes. Using the screen-printing technology throughout the whole fabrication process gives the ability to fabricate patterned films easily, and has the advantages of simple control and low cost, which makes it superior in mass production compared to previous studies. By encapsulating the AgNW with the GO layer, the electrodes obtained exhibit excellent optical and electrical properties (transmittance of 83.5% at 550 nm and sheet resistance of 11.9 Ohm/sq). Apart from optical and electrical properties, with GO as a protective layer, the reliability, bio-friendliness and long-term stability of AgNWs/GO hybrid electrodes have been greatly improved. In addition, AgNWs/GO electrodes fabricated on PET substrate also show excellent mechanical flexibility. We anticipate that AgNWs/GO electrodes will be promising materials for the implementation of emerging portable healthcare electronics such as wearable ECG monitoring.
The main challenges to the direct methanol fuel cells are the activity and durability of electrocatalysts. To alleviate such issues, a recently proposed strategy introduces an exotic element to form ...Pt‐based alloy nanostructures. This study reports a green route to prepare porous flowerlike Pt72Ru28 nanoalloys assembled with sub‐4.0 nm particles. The peak current density and mass activity on these as‐synthesized porous flowerlike Pt72Ru28 nanoalloys can be increased to 10.98 mA cm−2 and 1.70 A mg−1 Pt for methanol oxidation in acidic medium. They are respectively 4.19/3.54, 4.27/5.0, and 5.74/1.73 times those on the commercial Pt black, Pt50Ru50 black, and Ru50Pt50/C. These porous flowerlike Pt72Ru28 nanoalloys have a much higher long‐term durability than commercial Pt black, Pt50Ru50 black, and Ru50Pt50/C. More significantly, the porous Pt72Ru28 bimetallic nanoalloys have long‐term solvent durability after immersion in water for 16 months. The peak current density and mass activity on porous Pt72Ru28 nanoalloys are still 7.76 mA cm−2 and 1.2 A mg−1 Pt. These experimental results show an effective approach to the development of PtRu nanoalloys as electrocatalysts with substantially enhanced activity and durability for direct methanol fuel cells.
Porous Pt72Ru28 nanoalloys assembled with sub‐4.0 nm particles are successfully prepared. Specific activity and mass activity of Pt72Ru28 nanoalloys can boost to 10.98 mA cm−2 and 1.70 A mg−1 Pt toward methanol oxidation. After being kept for 16 months in water, the specific activity on Pt72Ru28 nanoalloys is 2.96, 3.02, and 4.06 times that on commercial Pt black, Pt50Ru50 black, and Pt50Ru50/C, respectively.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
A rapid, chemoselective and metal-free C-B bond-forming reaction of aryl iodides and bromides in aqueous solution at low temperatures was discovered. This reaction is amenable to batch and ...continuous-flow conditions and shows exceptional functional group tolerance and broad substrate scope regarding both the aryl halide and the borylating reagent. Initial mechanistic experiments indicated a photolytically generated aryl radical as the key intermediate.
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The generation of ultrarelativistic polarized positrons during the interaction of an ultrarelativistic electron beam with a counterpropagating two-color petawatt laser pulse is investigated ...theoretically. Our Monte Carlo simulation, based on a semiclassical model, incorporates photon emissions and pair productions, using spin-resolved quantum probabilities in the local constant field approximation, and describes the polarization of electrons and positrons for the pair production and photon emission processes, as well as the classical spin precession in between. The main reason for the polarization is shown to be the spin asymmetry of the pair production process in strong external fields, combined with the asymmetry of the two-color laser field. Employing a feasible scenario, we show that highly polarized positron beams, with a polarization degree of ζ≈60%, can be produced in a femtosecond timescale, with a small angular divergence, ∼74 mrad, and high density, ∼1014 cm−3. The laser-driven polarized positron source raises hope for providing an alternative for high-energy physics studies.
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The morphology of drops of graphene oxide (GO) inks produced by inkjet printing shows a distinctive coffee ring after drying when the mean diameter of the GO is below a critical size. Inks with ...larger diameter flakes do not show a coffee ring and the transition mean flake diameter decreases as the substrate temperature increases and when the printed drop size decreases. This behavior can be predicted with a model that compares the characteristic time for the agglomeration of high aspect ratio particles in suspension with the time scale for an evaporating liquid drop to begin receding during the drying process. The model is shown to accurately describe the transition from a coffee ring to a uniform dried deposit using a range of GO inks with mean flake size in the range 0.68–35.9 µm, drying temperatures of 20–60 °C, and drop sizes with contact diameter ranging from 30 to 800 µm.
Coffee ring formation is suppressed during drying drops of 2D material inks, when the mean flake diameter is above a critical size. The mechanism for this behavior is related to the conditions for contact line pinning during drying. A simple model is presented that produces excellent agreement with experimental results.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Conductive inks for the future printed electronics should have the following merits: high conductivity, flexibility, low cost, and compatibility with wide range of substrates. However, the ...state-of-the-art conductive inks based on metal nanoparticles are high in cost and poor in flexibility. Herein, we reported a highly conductive, low cost, and super flexible ink based on graphene nanoplatelets. The graphene ink has been screen-printed on plastic and paper substrates. Combined with postprinting treatments including thermal annealing and compression rolling, the printed graphene pattern shows a high conductivity of 8.81 × 104 S m–1 and good flexibility without significant conductivity loss after 1000 bending cycles. We further demonstrate that the printed highly conductive graphene patterns can act as current collectors for supercapacitors. The supercapacitor with the printed graphene pattern as the current collector and printed activated carbon as the active material shows a good rate capability of up to 200 mV s–1. This work potentially provides a promising route toward the large-scale fabrication of low cost yet flexible printed electronic devices.
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Chemical protein modifications facilitate the investigation of natural posttranslational protein modifications and allow the design of proteins with new functions. Proteins can be modified at a late ...stage on amino acid side chains by chemical methods. The indole moiety of tryptophan residues is an emerging target of such chemical modification strategies because of its unique reactivity and low abundance. This review provides an overview of the recently developed methods of tryptophan modification at the peptide and protein levels.
Chemical modification contributes to the comprehension of natural posttranslational modifications and the achievement of further designed functions of protein. Compared with other residues, the low‐abundance amino acid, tryptophan (Trp), has advantages in selectivity and attracts high concentration. In this review, the late‐stage modifications targeting Trp developed in recent years are summarized.
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Preparation of inks with proper rheology performance is the key for extrusion based 3D printing. In this work, extrusion based 3D printing graphene oxide (GO)/geopolymer (GOGP) nanocomposite was ...reported for the first time. The addition of GO in geopolymeric aqueous mixture (alumiosilicate and alkaline-source particles) dramatically changes its rheology properties, and enable the 3D printing that cannot be realized solely by geopolymer. The 3D printing GOGP structures exhibited high mechanical properties with compressive strength higher than 30 MPa, and electrical conductivity of 102 S/m was achieved after annealing, which is among the highest conductive ceramic nanocomposites. We expect that the rheology modification mechanism proposed in this study will facilitate the 3D printing of diverse materials, as well as the understanding of the interaction between GO and hydrophilic particles.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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