Two-dimensional crystals are emerging materials for nanoelectronics. Development of the field requires candidate systems with both a high carrier mobility and, in contrast to graphene, a sufficiently ...large electronic bandgap. Here we present a detailed theoretical investigation of the atomic and electronic structure of few-layer black phosphorus (BP) to predict its electrical and optical properties. This system has a direct bandgap, tunable from 1.51 eV for a monolayer to 0.59 eV for a five-layer sample. We predict that the mobilities are hole-dominated, rather high and highly anisotropic. The monolayer is exceptional in having an extremely high hole mobility (of order 10,000 cm(2) V(-1) s(-1)) and anomalous elastic properties which reverse the anisotropy. Light absorption spectra indicate linear dichroism between perpendicular in-plane directions, which allows optical determination of the crystalline orientation and optical activation of the anisotropic transport properties. These results make few-layer BP a promising candidate for future electronics.
Background and Aims
Hepatic macrophages can be activated by many factors such as gut‐derived bacterial components and factors released from damaged hepatocytes. Macrophage polarization toward a ...proinflammatory phenotype (M1) represents an important event in the disease progression of nonalcoholic fatty liver disease (NAFLD). However, the underlying molecular mechanisms remain incompletely understood. Exosomes have been identified as important mediators for cell–cell communication by transferring various biological components such as microRNAs (miRs), proteins, and lipids. The role of exosomes in crosstalk between hepatocytes and macrophages in disease progression of NAFLD is yet to be explored.
Approach and Results
In the present study, we reported that lipotoxic injury–induced release of hepatocyte exosomes enriched with miR‐192‐5p played a critical role in the activation of M1 macrophages and hepatic inflammation. Serum miR‐192‐5p levels in patients with NAFLD positively correlated with hepatic inflammatory activity score and disease progression. Similarly, the serum miR‐192‐5p level and the number of M1 macrophages, as well as the expression levels of the hepatic proinflammatory mediators, were correlated with disease progression in high‐fat high‐cholesterol diet–fed rat models. Lipotoxic hepatocytes released more miR‐192‐5p‐enriched exosomes than controls, which induced M1 macrophage (cluster of differentiation 11b–positive CD11b+/CD86+) activation and increase of inducible nitric oxide synthase, interleukin 6, and tumor necrosis factor alpha expression. Furthermore, hepatocyte‐derived exosomal miR‐192‐5p inhibited the protein expression of the rapamycin‐insensitive companion of mammalian target of rapamycin (Rictor), which further inhibited the phosphorylation levels of Akt and forkhead box transcription factor O1 (FoxO1) and resulted in activation of FoxO1 and subsequent induction of the inflammatory response.
Conclusions
Hepatocyte‐derived exosomal miR‐192‐5p plays a critical role in the activation of proinflammatory macrophages and disease progression of NAFLD through modulating Rictor/Akt/FoxO1 signaling. Serum exosomal miR‐192‐5p represents a potential noninvasive biomarker and therapeutic target for nonalcoholic steatohepatitis.
AIM To investigate whether gut microbiota metabolite sodium butyrate(Na B)is an effective substance for attenuating non-alcoholic fatty liver disease(NAFLD)and the internal mechanisms.METHODS Male ...C57BL/6J mice were divided into three groups,normal control were fed standard chow and model group were fed a high-fat diet(HFD)for 16 wk,the intervention group were fed HFD for 16 wk and treated with Na B for 8 wk.Gut microbiota from each group were detected at baseline and at 16 wk,liver histology were evaluated and gastrointestinal barrier indicator such as zonula occluden-1(ZO-1)were detected by immunohistochemistry and realtime-PCR,further serum or liver endotoxin were determined by ELISA and inflammation-or metabolism-associated genes were quantified by real-time PCR.RESULTS Na B corrected the HFD-induced gut microbiota imbalance in mice,while it considerably elevated the abundances of the beneficial bacteria Christensenellaceae,Blautia and Lactobacil us.These bacteria can produce butyric acid in what seems like a virtuous circle.And butyrate restored HFD induced intestinal mucosa damage,increased the expression of ZO-1 in small intestine,further decreased the levels of gut endotoxin in serum and liver compared with HF group.Endotoxin-associated genes such as TLR4 and Myd88,pro-inflammation genes such as MCP-1,TNF-α,IL-1,IL-2,IL-6 and IFN-γin liver or epididymal fat were obviously downregulated after Na B intervention.Liver inflammation and fat accumulation were ameliorated,the levels of TG and cholesterol in liver were decreased after Na B intervention,NAS score was significantly decreased,metabolic indices such as FBG and HOMA-IR and liver function indicators ALT and AST were improved compared with HF group.CONCLUSION Na B may restore the dysbiosis of gut microbiota to attenuate steatohepatitis,which is suggested to be a potential gut microbiota modulator and therapeutic substance for NAFLD.
Recent progress in addressing electrically driven single‐molecule behaviors has opened up a path toward the controllable fabrication of molecular devices. Herein, the selective fabrication of ...single‐molecule junctions is achieved by employing the external electric field. For molecular junctions with methylthio (–SMe), thioacetate (–SAc), amine (–NH2), and pyridyl (–PY), the evolution of their formation probabilities along with the electric field is extracted from the plateau analysis of individual single‐molecule break junction traces. With the increase of the electric field, the SMe‐anchored molecules show a different trend in the formation probability compared to the other molecular junctions, which is consistent with the density functional theory calculations. Furthermore, switching from an SMe‐anchored junction to an SAc‐anchored junction is realized by altering the electric field in a mixed solution. The results in this work provide a new approach to the controllable fabrication and modulation of single‐molecule junctions and other bottom‐up nanodevices at molecular scales.
The selective fabrication of single‐molecule junctions is achieved by interface engineering under the external electric field. This work offers an unprecedented opportunity to investigate single‐molecule behaviors, manipulate single‐molecule in solution, and integrate functional molecules into the specific sites of molecular devices.
Microbial metabolites have emerged as critical components that mediate the metabolic effects of the gut microbiota. Here, we show that indole-3-propionic acid (IPA), a tryptophan metabolite produced ...by gut bacteria, is a potent anti-non-alcoholic steatohepatitis (NASH) microbial metabolite. Here, we demonstrate that administration of IPA modulates the microbiota composition in the gut and inhibits microbial dysbiosis in rats fed a high-fat diet. IPA induces the expression of tight junction proteins, such as ZO-1 and Occludin, and maintains intestinal epithelium homeostasis, leading to a reduction in plasma endotoxin levels. Interestingly, IPA inhibits NF-κB signaling and reduces the levels of proinflammatory cytokines, such as TNFα, IL-1β, and IL-6, in response to endotoxin in macrophages to repress hepatic inflammation and liver injury. Moreover, IPA is sufficient to inhibit the expression of fibrogenic and collagen genes and attenuate diet-induced NASH phenotypes. The beneficial effects of IPA on the liver are likely mediated through inhibiting the production of endotoxin in the gut. These findings suggest a protective role of IPA in the control of metabolism and uncover the gut microbiome and liver cross-talk in regulating the intestinal microenvironment and liver pathology via a novel dietary nutrient metabolite. IPA may provide a new therapeutic strategy for treating NASH.
As a major branch of hybrid perovskites, two-dimensional (2D) hybrid double perovskites are expected to be ideal systems for exploring novel ferroelectric properties, because they can accommodate a ...variety of organic cations and allow diverse combinations of different metal elements. However, no 2D hybrid double perovskite ferroelectric has been reported since the discovery of halide double perovskites in the 1930s. Based on trivalent rare-earth ions and chiral organic cations, we have designed a new family of 2D rare-earth double perovskite ferroelectrics, A4MIMIII(NO3)8, where A is the organic cation, MI is the alkaline metal or ammonium ion, and MIII is the rare-earth ion. This is the first time that ferroelectricity is realized in 2D hybrid double perovskite systems. These ferroelectrics have achieved high-temperature ferroelectricity and photoluminescent properties. By varying the rare-earth ion, variable photoluminescent properties can be achieved. The results reveal that the 2D rare-earth double perovskite systems provide a promising platform for achieving multifunctional ferroelectricity.
Visible-light driven photoconversion of CO
into energy carriers is highly important to the natural carbon balance and sustainable development. Demonstrated here is the adenine-dependent CO
...photoreduction performance in green biomimetic metal-organic frameworks. Photocatalytic results indicate that AD-MOF-2 exhibited a very high HCOOH production rate of 443.2 μmol g
h
in pure aqueous solution, and is more than two times higher than that of AD-MOF-1 (179.0 μmol g
h
) in acetonitrile solution. Significantly, experimental and theoretical evidence reveal that the CO
photoreduction reaction mainly takes place at the aromatic nitrogen atom of adenine molecules through a unique o-amino-assisted activation rather than at the metal center. This work not only serves as an important case study for the development of green biomimetic photocatalysts used for artificial photosynthesis, but also proposes a new catalytic strategy for efficient CO
photoconversion.
Visible‐light driven photoconversion of CO2 into energy carriers is highly important to the natural carbon balance and sustainable development. Demonstrated here is the adenine‐dependent CO2 ...photoreduction performance in green biomimetic metal–organic frameworks. Photocatalytic results indicate that AD‐MOF‐2 exhibited a very high HCOOH production rate of 443.2 μmol g−1 h−1 in pure aqueous solution, and is more than two times higher than that of AD‐MOF‐1 (179.0 μmol g−1h−1) in acetonitrile solution. Significantly, experimental and theoretical evidence reveal that the CO2 photoreduction reaction mainly takes place at the aromatic nitrogen atom of adenine molecules through a unique o‐amino‐assisted activation rather than at the metal center. This work not only serves as an important case study for the development of green biomimetic photocatalysts used for artificial photosynthesis, but also proposes a new catalytic strategy for efficient CO2 photoconversion.
Eco‐friendly terms: Two biomimetic metal–organic frameworks (MOFs) were assembled with eco‐friendly components and used as photocatalysts for CO2‐to‐HCOOH conversion. One of the synthesized MOFs exhibited a very high HCOOH production rate of 443.2 μmol g−1 h−1 in pure aqueous solution.
Severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection can cause coronavirus disease 2019 (COVID‐19), an acute respiratory inflammation that has emerged worldwide since December 2019, ...and it quickly became a global epidemic. Inflammatory bowel disease (IBD) is a group of chronic nonspecific intestinal inflammatory diseases whose etiology has not been elucidated. The two have many overlapping symptoms in clinical presentation, such as abdominal pain, diarrhea, pneumonia, etc. Imbalance of the autoimmune system in IBD patients and long‐term use of immunosuppressive drugs may increase the risk of infection; and systemic symptoms caused by COVID‐19 may also induce or exacerbate intestinal inflammation. It has been found that the SARS‐CoV‐2 receptor angiotensin converting enzyme 2, which is highly expressed in the lung and intestine, is an inflammatory protective factor, and is downregulated and upregulated in COVID‐19 and IBD, respectively, suggesting that there may be a coregulatory pathway. In addition, the immune activation pattern of COVID‐19 and the cytokine storm in the inflammatory response have similar roles in IBD, indicating that the two diseases may influence each other. Therefore, this review aimed to address the following research questions: whether SARS‐CoV‐2 infection leads to the progression of IBD; whether IBD increases the risk of COVID‐19 infection and poor prognosis; possible common mechanisms and genetic cross‐linking between the two diseases; new treatment and care strategies for IBD patients, and the feasibility and risk of vaccination in the context of the COVID‐19 epidemic.
Few-layer bismuthene is an emerging two-dimensional material in the fields of physics, chemistry, and material science. However, its nonlinear optical property and the related photonics device have ...been seldom studied so far. Here, we demonstrate a sub-200 fs soliton mode-locked erbium-doped fiber laser (EDFL) using a microfiber-based bismuthene saturable absorber for the first time, to the best of our knowledge. The bismuthene nanosheets are synthesized by the sonochemical exfoliation method and transferred onto the taper region of a microfiber by the optical deposition method. Stable soliton pulses centered at 1561 nm with the shortest pulse duration of about 193 fs were obtained. Our findings unambiguously imply that apart from its fantastic electric and thermal properties, few-layer bismuthene may also possess attractive optoelectronic properties for nonlinear photonics, such as mode-lockers, Q-switchers, optical modulators and so on.
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