Microbial biochemicals have been indicated as the primary stimulators of innate immunity, the first line of the body's defence against infections. However, the influence of topological features on a ...microbe's surface on immune responses remains largely unknown. Here we demonstrate the ability of TiO
microparticles decorated with nanospikes (spiky particles) to activate and amplify the immune response in vitro and in vivo. The nanospikes exert mechanical stress on the cells, which results in potassium efflux and inflammasome activation in macrophages and dendritic cells during phagocytosis. The spiky particles augment antigen-specific humoral and cellular immune responses in the presence of monophosphoryl lipid A and elicit protective immunity against tumour growth and influenza viral infection. The study offers insights into how surface physical cues can tune the activation of innate immunity and provides a basis for engineering particles with increased immunogenicity and adjuvanticity.
The authors provide an epidemiologic analysis of the first 425 confirmed cases of infection with the novel coronavirus in Wuhan, China. This analysis provides estimates of the epidemic doubling time ...and the basic reproductive number and shows clear evidence of sustained human-to-human transmission.
Hybrid graphene aerogels (HGA) consisting of graphene oxide (GO) and graphene nanoplatelets (GNP) were prepared and introduced into polyethylene glycol (PEG) via vacuum impregnation, aiming at ...obtaining composite phase change materials (PCMs) with high thermal conductivity, outstanding shape-stabilization, high energy storage density, commendable thermal repeatability and the ability to light-to-heat energy storage. GO nanosheets formed a three-dimensional supporting network to keep the shape of PEG stable during phase change and GNP dispersed uniformity along the network structure of GO and thus a thermal conductive pathway was constructed. The incorporation of HGA remarkably enhanced the thermal conductivity and shape-stabilization of the composite PCMs. The PEG/HGA composite PCM with only ca. 0.45 wt% GO and ca. 1.8 wt% GNP, showed an enhanced thermal conductivity of 1.43 W/mK from 0.31 W/mK of pure PEG and an improvement of 361%, much higher than the improvement that can be achieved by solution or melt blending. Moreover, an energy conversion from light to heat was realized with the composite PCMs. Thus, this work provides a simple, green and environmentally friendly way to achieve simultaneous enhancement of the thermal conductivity, energy storage density and shape-stabilization of PCMs and realize light-to-thermal energy conversion.
Multiresponsive flexile sensors with strain, temperature, humidity, and other sensing abilities serving as real electronic skin (e‐skin) have manifested great application potential in flexible ...electronics, artificial intelligence (AI), and Internet of Things (IoT). Although numerous flexible sensors with sole sensing function have already been reported since the concept of e‐skin, that mimics the sensing features of human skin, was proposed about a decade ago, the ones with more sensing capacities as new emergences are urgently demanded. However, highly integrated and highly sensitive flexible sensors with multiresponsive functions are becoming a big thrust for the detection of human body motions, physiological signals (e.g., skin temperature, blood pressure, electrocardiograms (ECG), electromyograms (EMG), sweat, etc.) and environmental stimuli (e.g., light, magnetic field, volatile organic compounds (VOCs)), which are vital to real‐time and all‐round human health monitoring and management. Herein, this review summarizes the design, manufacturing, and application of multiresponsive flexible sensors and presents the future challenges of fabricating these sensors for the next‐generation e‐skin and wearable electronics.
Multiresponsive flexible sensors susceptible to various stimuli including strain, temperature, humidity, etc., have been rapidly emerging due to their great potential application in e‐skins. Thus, the recent progress of multiresponsive flexible sensors including the design strategies (the choices of sensing materials and mechanisms, and structure designs and fabrication methods), applications and prospects is reviewed to promote further development of e‐skins.
Background and Purpose
Gut microbiota dysbiosis induced by acute pancreatitis (AP) exacerbates pancreatic injury and systemic inflammatory responses. The alleviation of gut microbiota dysbiosis ...through faecal microbiota transplantation (FMT) is considered a potential strategy to reduce tissue damage and inflammation in many clinical disorders. Here, we aim to investigate the effect of gut microbiota and microbiota‐derived metabolites on AP and further clarify the mechanisms associated with pancreatic damage and inflammation.
Experimental Approach
AP rat and mouse models were established by administration of caerulein or sodium taurocholate in vivo. Pancreatic acinar cells were exposed to caerulein and lipopolysaccharide in vitro to simulate AP.
Key Results
Normobiotic FMT alleviated AP‐induced gut microbiota dysbiosis and ameliorated the severity of AP, including mitochondrial dysfunction, oxidative damage and inflammation. Normobiotic FMT induced higher levels of NAD+ (nicotinamide adenine dinucleotide)‐associated metabolites, particularly nicotinamide mononucleotide (NMN). NMN administration mitigated AP‐mediated mitochondrial dysfunction, oxidative damage and inflammation by increasing pancreatic NAD+ levels. Similarly, overexpression of the NAD+‐dependent mitochondrial deacetylase sirtuin 3 (SIRT3) alleviated the severity of AP. Furthermore, SIRT3 deacetylated peroxiredoxin 5 (PRDX5) and enhanced PRDX5 protein expression, thereby promoting its antioxidant and anti‐inflammatory activities in AP. Importantly, normobiotic FMT‐mediated NMN metabolism induced SIRT3–PRDX5 pathway activation during AP.
Conclusion and Implications
Gut microbiota‐derived NMN alleviates the severity of AP by activating the SIRT3–PRDX5 pathway. Normobiotic FMT could be served as a potential strategy for AP treatment.
Here an efficient copper‐catalyzed cascade cyclization of azide‐ynamides via α‐imino copper carbene intermediates is reported, representing the first generation of α‐imino copper carbenes from ...alkynes. This protocol enables the practical and divergent synthesis of an array of polycyclic N‐heterocycles in generally good to excellent yields with broad substrate scope and excellent diastereoselectivities. Moreover, an asymmetric azide–ynamide cyclization has been achieved with high enantioselectivities (up to 98:2 e.r.) by employing BOX‐Cu complexes as chiral catalysts. Thus, this protocol constitutes the first example of an asymmetric azide–alkyne cyclization. The proposed mechanistic rationale for this cascade cyclization is further supported by theoretical calculations.
An efficient copper‐catalyzed cascade cyclization of azide‐ynamides via α‐imino copper carbene intermediates is disclosed, enabling divergent synthesis of polycyclic N‐heterocycles in generally good to excellent yields with broad substrate scope and excellent diastereoselectivities, representing the first generation of α‐imino copper carbenes directly from alkynes. The asymmetric azide–ynamide cyclization has been achieved with high enantioselectivities.
Ionic hydrogels, a class of intrinsically stretchable and conductive materials, are widely used in soft electronics. However, the easy freezing and drying of water-based hydrogels significantly limit ...their long-term stability. Here, a facile solvent-replacement strategy is developed to fabricate ethylene glycol (Eg)/glycerol (Gl)-water binary antifreezing and antidrying organohydrogels for ultrastretchable and sensitive strain sensing within a wide temperature range. Because of the ready formation of strong hydrogen bonds between Eg/Gl and water molecules, the organohydrogels gain exceptional freezing and drying tolerance with retained deformability, conductivity, and self-healing ability even stay at extreme temperature for a long time. Thus, the fabricated strain sensor displays a gauge factor of 6, which is much higher than previously reported values for hydrogel-based strain sensors. Furthermore, the strain sensor exhibits a relatively wide strain range (0.5–950%) even at −18 °C. Various human motions with different strain levels are monitored by the strain sensor with good stability and repeatability from −18 to 25 °C. The organohydrogels maintained the strain sensing capability when exposed to ambient air for nine months. This work provides new insight into the fabrication of stable, ultrastretchable, and ultrasensitive strain sensors using chemically modified organohydrogel for emerging wearable electronics.
Social Collaborative Filtering by Trust Yang, Bo; Lei, Yu; Liu, Jiming ...
IEEE transactions on pattern analysis and machine intelligence,
08/2017, Volume:
39, Issue:
8
Journal Article
Peer reviewed
Recommender systems are used to accurately and actively provide users with potentially interesting information or services. Collaborative filtering is a widely adopted approach to recommendation, but ...sparse data and cold-start users are often barriers to providing high quality recommendations. To address such issues, we propose a novel method that works to improve the performance of collaborative filtering recommendations by integrating sparse rating data given by users and sparse social trust network among these same users. This is a model-based method that adopts matrix factorization technique that maps users into low-dimensional latent feature spaces in terms of their trust relationship, and aims to more accurately reflect the users reciprocal influence on the formation of their own opinions and to learn better preferential patterns of users for high-quality recommendations. We use four large-scale datasets to show that the proposed method performs much better, especially for cold start users, than state-of-the-art recommendation algorithms for social collaborative filtering based on trust.
Axially chiral biaryls widely exist in natural products and pharmaceuticals and are used as chiral ligands and catalysts in asymmetric synthesis. Compared to the well‐established axially chiral ...6‐membered biaryl skeletons, examples of 5‐membered biaryls have been quite scarce, and mono‐substituted 3‐arylpyrrole atropisomers have not been reported. Here, we disclose a copper‐catalyzed atroposelective diyne cyclization for the construction of a range of axially chiral arylpyrrole biaryls in good to excellent yields with generally excellent enantioselectivities via oxidation and X−H insertion of vinyl cations. Importantly, this protocol not only represents the first synthesis of mono‐substituted 3‐arylpyrrole atropisomers, but also constitutes the first example of atroposelective diyne cyclization and the first atropisomer construction via vinyl cations. Theoretical calculations further support the mechanism of vinyl cation‐involved cyclization and elucidate the origin of enantioselectivity.
A novel copper‐catalyzed atroposelective diyne cyclization enables the efficient synthesis of a range of axially chiral arylpyrrole biaryls in good to excellent yields with generally excellent enantioselectivities via oxidation and X−H insertion of vinyl cations. This method gives the first synthesis of mono‐substituted 3‐arylpyrrole atropisomers and the first atroposelective diyne cyclization.
Stretchable strain sensors suffer the trade‐off between sensitivity and linear sensing range. Developing sensors with both high sensitivity and wide linear range remains a formidable challenge. ...Different from conventional methods that rely on the structure design of sensing nanomaterial or substrate, here a heterogeneous‐surface strategy for silver nanowires (AgNWs) and MXene is proposed to construct a hierarchical microcrack (HMC) strain sensor. The heterogeneous surface with distinct differences in cracks and adhesion strengths divides the sensor into two regions. One region contributes to high sensitivity through penetrating microcracks of the AgNW/MXene composite film during stretching. The other region maintains conductive percolation pathways to provide a wide linear sensing range through network microcracks. As a result, the HMC sensor exhibits ultrahigh sensitivity (gauge factor ≈ 244), broad linear range (ɛ = 60%, R2 ≈ 99.25%), and fast response time (<30 ms). These merits are confirmed in the detection of large and subtle human motions and digital joint movement for Morse coding. The manipulation of cracks on the heterogeneous surface provides a new paradigm for designing high‐performance stretchable strain sensors.
The MXene‐/silver‐nanowire‐composite‐based strain sensors with hierarchical microcrack are fabricated by a heterogeneous‐surface strategy. The sensor achieves ultrahigh sensitivity (gauge factor ≈ 244), excellent linearity (R2 ≈ 99.25%) in the strain range of 0–60%, a fast response time (less than 30 ms), and outstanding stability (6000 cycles).