Covalent organic frameworks (COFs) are of great potential as adsorbents owing to their tailorable functionalities, low density and high porosity. However, their intrinsically stacked two‐dimensional ...(2D) structure limits the full use of their complete surface for sorption, especially the internal pores. The construction of ultrathin COFs could increase the exposure of active sites to the targeted molecules in a pollutant environment. Herein, an ultrathin COF with a uniform thickness of ca. 2 nm is prepared employing graphene as the surface template. The resulting hybrid aerogel with an ultralow density (7.1 mg cm−3) exhibits the ability to remove organic dye molecules of different sizes with high efficiency. The three‐dimensional (3D) macroporous structure and well‐exposed adsorption sites permit rapid diffusion of solution and efficient adsorption of organic pollutants, thereby, greatly contributing to its enhanced uptake capacity. This work highlights the effect of COF layer thickness on adsorption performance.
An ultrathin anionic covalent organic framework (COF) was constructed homogeneously on the surface of a graphene template via a facile hydrothermal method. Compared with bulk COF powder, the anionic ultrathin COF exhibited the ability to remove cationic organic dyes of different sizes with higher efficiency.
As domestic athletes and other sports become more and more popular, the health protection of athletes has gradually attracted people's attention, and the heart rate monitoring of machine learning ...sensors has gradually been understood by people. In order to in-depth study the current status of the role of machine learning sensors in wearable heart rate monitoring, this article uses the new and old sensor comparison method, the field survey method and the human sample test method, collects samples, analyzes the machine learning sensor, and streamlines the algorithm. And create a sensor for wearable heart rate monitoring. In studying the innovation and improvement of the comparison between the new sensor and the old one, this paper uses the shimmer node on the Tiny-OS platform to collect a total of 36 sets of heart rate data of three men and three women in different exercise states, and uses two types of algorithms to calculate the results. It shows that the calculation time of the algorithm proposed in the paper is 0.21, the traditional electrocardiogram (ECG) algorithm is 0.28, and the new algorithm has lower time complexity. Research on the accuracy of the sensor in practical application shows that the recognition rate of riding a bicycle is almost close to 1.00, which fully meets the 0.96 recognition requirement of this system. Although, the single recognition rate of standing still did not reach 0.95. However, the total average recognition rate of the nine sports is 0.971, which is already above 0.96, which proves that the average recognition rate of the monitoring system is above 96%. The system is considered to be a basic design success. It is basically realized that starting from the wearable heart rate monitoring, a machine learning sensor that can be put into large-scale application is designed. KCI Citation Count: 0
Skeletal reorganization reactions have emerged as an intriguing tool for converting readily available compounds into complicated molecules inaccessible by traditional methods. Herein, we report a ...unique skeleton‐reorganizing coupling reaction of cycloheptatriene and cycloalkenones with amines. In the presence of Rh/acid catalysis, cycloheptatriene can selectively couple with anilines to deliver fused 1,2‐dihydroquinoline products. Mechanistic studies indicate that the retro‐Mannich type ring‐opening and subsequent intramolecular Povarov reaction account for the ring reorganization. Our mechanistic studies also revealed that skeleton‐reorganizing amination between anilines and cycloalkenones can be achieved with acid. The synthetic utilization of this skeleton‐reorganizing coupling reaction was showcased with a gram‐scale reaction, synthetic derivatizations, and the late‐stage modification of commercial drugs.
An unusual catalytic coupling reaction of cycloheptatriene and cycloalkenones with amines proceeds through a skeleton‐reorganization process for the selective synthesis of fused 1,2‐dihydroquinolines. Mechanistic studies indicate that the reactions proceed through a retro‐Mannich‐type ring‐opening and a subsequent intramolecular Povarov process.
Adapter trimming is a prerequisite step for analyzing next-generation sequencing (NGS) data when the reads are longer than the target DNA/RNA fragments. Although typically used in small RNA ...sequencing, adapter trimming is also used widely in other applications, such as genome DNA sequencing and transcriptome RNA/cDNA sequencing, where fragments shorter than a read are sometimes obtained because of the limitations of NGS protocols. For the newly emerged Nextera long mate-pair (LMP) protocol, junction adapters are located in the middle of all properly constructed fragments; hence, adapter trimming is essential to gain the correct paired reads. However, our investigations have shown that few adapter trimming tools meet both efficiency and accuracy requirements simultaneously. The performances of these tools can be even worse for paired-end and/or mate-pair sequencing.
To improve the efficiency of adapter trimming, we devised a novel algorithm, the bit-masked k-difference matching algorithm, which has O(kn) expected time with O(m) space, where k is the maximum number of differences allowed, n is the read length, and m is the adapter length. This algorithm makes it possible to fully enumerate all candidates that meet a specified threshold, e.g. error ratio, within a short period of time. To improve the accuracy of this algorithm, we designed a simple and easy-to-explain statistical scoring scheme to evaluate candidates in the pattern matching step. We also devised scoring schemes to fully exploit the paired-end/mate-pair information when it is applicable. All these features have been implemented in an industry-standard tool named Skewer (https://sourceforge.net/projects/skewer). Experiments on simulated data, real data of small RNA sequencing, paired-end RNA sequencing, and Nextera LMP sequencing showed that Skewer outperforms all other similar tools that have the same utility. Further, Skewer is considerably faster than other tools that have comparative accuracies; namely, one times faster for single-end sequencing, more than 12 times faster for paired-end sequencing, and 49% faster for LMP sequencing.
Skewer achieved as yet unmatched accuracies for adapter trimming with low time bound.
Diverse eukaryotic hosts produce virus-derived small interfering RNAs (siRNAs) to direct antiviral immunity by RNA interference (RNAi). However, it remains unknown whether the mammalian RNAi pathway ...has a natural antiviral function. Here, we show that infection of hamster cells and suckling mice by Nodamura virus (NoV), a mosquito-transmissible RNA virus, requires RNAi suppression by its B2 protein. Loss of B2 expression or its suppressor activity leads to abundant production of viral siRNAs and rapid clearance of the mutant viruses in mice. However, viral small RNAs detected during virulent infection by NoV do not have the properties of canonical siRNAs. These findings have parallels with the induction and suppression of antiviral RNAi by the related Flock house virus in fruit flies and nematodes and reveal a mammalian antiviral immunity mechanism mediated by RNAi.
Depending on the reactant property and reaction mechanism, one major regioisomer can be favored in a reaction that involves multiple active sites. Herein, an orthogonal regulation of nucleophilic and ...electrophilic sites in the regiodivergent hydroamination of isoprene with indazoles is demonstrated. Under Pd‐hydride catalysis, the 1,2‐ or 4,3‐insertion pathway with respect to the electrophilic sites on isoprene could be controlled by the choice of ligands. In terms of the nucleophilic sites on indazoles, the reaction occurs at either the N1‐ or N2‐position of indazoles is governed by the acid co‐catalysts. Preliminary experimental studies have been performed to rationalize the mechanism and regioselectivity. This study not only contributes a practical tool for selective functionalization of isoprene, but also provides a guide to manipulate the regioselectivity for the N‐functionalization of indazoles.
The Pd‐catalyzed regiodivergent coupling reactions between indazoles and isoprene have been developed through the orthogonal regulation of nucleophilic and electrophilic sites.
Superelastic and fatigue‐resistant materials that can work over a wide temperature range are highly desired for diverse applications. A morphology‐retained and scalable carbonization method is ...reported to thermally convert a structural biological material (i.e., bacterial cellulose) into graphitic carbon nanofiber aerogel by engineering the pyrolysis chemistry. The prepared carbon aerogel perfectly inherits the hierarchical structures of bacterial cellulose from macroscopic to microscopic scales, resulting in remarkable thermomechanical properties. In particular, it maintains superelasticity without plastic deformation even after 2 × 106 compressive cycles and exhibits exceptional temperature‐invariant superelasticity and fatigue resistance over a wide temperature range at least from −100 to 500 °C. This aerogel shows unique advantages over polymeric foams, metallic foams, and ceramic foams in terms of thermomechanical stability and fatigue resistance, with the realization of scalable synthesis and the economic advantage of biological materials.
A graphitic carbon nanofiber aerogel (CNFA) is fabricated from structural biological material (i.e., bacterial cellulose) by engineering pyrolysis chemistry, which perfectly inherits the hierarchical structures from macroscopic to microscopic scales. This CNFA maintains superelasticity without plastic deformation after 2 × 106 compressive cycles, and exhibits temperature‐invariant superelasticity and fatigue resistance over a wide temperature range from −100 to 500 °C.
This paper proposes two primary pathways for online teaching and virtual music classrooms constructed using virtual reality technology and establishes a corresponding technical framework. In the ...online teaching mode, an online teaching platform is built, and an improved genetic algorithm is proposed for the intelligent grouping problem, which introduces the individual similarity elimination operation and incorporates simulated annealing to solve the problem of insufficient search capability. Meanwhile, in order to build a virtual music classroom, a dynamic light projection algorithm is proposed to reconstruct a three-dimensional model of human movement, and a multi-feature fusion algorithm is used to match the weights assigned to the human body's action gestures. In the evaluation of the teaching effect of the application of the technology framework, the piano art students are taken as the research object, and the experimental class and the control class are set up to carry out the teaching practice. In the evaluation of the learning effect, the completion degree of music and artistic performance of students in the experimental class was 83.65 and 82.66, which was significantly better than that of the control class (P<0.05). The overall degree of cognition, emotional attitude, and value recognition of traditional music culture was also significantly better than that of the control class (P<0.05).
Induction and suppression of antiviral RNA interference (RNAi) has been observed in mammals during infection with at least seven distinct RNA viruses, including some that are pathogenic in humans. ...However, while the cell‐autonomous immune response mediated by antiviral RNAi is gradually being recognized, little is known about systemic antiviral RNAi in mammals. Furthermore, extracellular vesicles (EVs) also function in viral signal spreading and host immunity. Here, we show that upon antiviral RNAi activation, virus‐derived small‐interfering RNAs (vsiRNAs) from Nodamura virus (NoV), Sindbis virus (SINV), and Zika virus (ZIKV) enter the murine bloodstream via EVs for systemic circulation. vsiRNAs in the EVs are biologically active, since they confer RNA–RNA homology‐dependent antiviral activity in both cultured cells and infant mice. Moreover, we demonstrate that vaccination with a live‐attenuated virus, rendered deficient in RNAi suppression, induces production of stably maintained vsiRNAs and confers protective immunity against virus infection in mice. This suggests that vaccination with live‐attenuated VSR (viral suppressor of RNAi)‐deficient mutant viruses could be a new strategy to induce immunity.
Synopsis
The cell‐autonomous immune response mediated by antiviral RNAi in mammals is gradually being recognized; however, little is known about systemic antiviral RNAi in mammals. This study shows that virus‐derived small‐interfering RNAs (vsiRNAs) enter the blood stream for systemic circulation via extracellular vesicles (EVs).
Infection of suckling mice with a VSR (viral suppressor of RNAi)‐deficient mutant of NoV, NoVΔB2, provides immunity toward a lethal challenge with NoV.
vsiRNAs derived from NoVΔB2 confer antiviral activity through Ago2‐mediated RNAi and remain stable in vivo following clearance of the virus.
Immunization with live NoVΔB2 or vsiRNA‐containing EVs protects mice from a later NoV challenge.
EV‐associated vsiRNAs confer homology‐dependent antiviral activity in both cell culture and infant mice.
Carbon aerogels with 3D networks of interconnected nanometer‐sized particles exhibit fascinating physical properties and show great application potential. Efficient and sustainable methods are ...required to produce high‐performance carbon aerogels on a large scale to boost their practical applications. An economical and sustainable method is now developed for the synthesis of ultrathin carbon nanofiber (CNF) aerogels from the wood‐based nanofibrillated cellulose (NFC) aerogels via a catalytic pyrolysis process, which guarantees high carbon residual and well maintenance of the nanofibrous morphology during thermal decomposition of the NFC aerogels. The wood‐derived CNF aerogels exhibit excellent electrical conductivity, a large surface area, and potential as a binder‐free electrode material for supercapacitors. The results suggest great promise in developing new families of carbon aerogels based on the controlled pyrolysis of economical and sustainable nanostructured precursors.
Nano‐woodwork: An economical and sustainable method has now been developed for the synthesis of ultrathin carbon nanofiber (CNF) aerogels by engineering the thermal decomposition chemistry of nanofibrillated wood cellulose. This work suggests great promise in developing new families of carbon aerogels based on the controlled pyrolysis of sustainable nanostructured precursors.
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