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A consensus control scheme is developed for a class of leader-follower multiagent systems with a fuzzy dead zone constraint. Differently from previous work, the method developed implements a predefined convergence of tracking errors for multiagent systems; especially, the dynamic model for each follower has a fuzzy dead zone input. To solve the problem, not only a set of smooth functions are used within the control design to increase the stability of the systems but also the unfuzziness and center-of-gravity method are used to analyze and process the actuator constraint model, where each slope of the dead zone is uncertain and fuzzy. It is verified that the method developed effectively guarantees that the tracking errors of multiagent systems can converge to a predefined interval; that is, the problem of better asymptotic consensus performance for nonlinear multiagent systems is solved. Simulation illustrates the results obtained.

MicroRNAs (miRNAs), as the small, non-coding, evolutionary conserved, and post-transcriptional gene regulators of the genome, have been highly associated with various diseases such as cancers, viral infections, and cardiovascular diseases. Several techniques have been established to detect miRNAs, including northern blotting, real-time polymerase chain reaction (RT-PCR), and fluorescent microarray platform. However, it remains a significant challenge to develop sensitive, accurate, rapid, and cost-effective methods to detect miRNAs due to their short size, high similarity, and low abundance. The electrochemical biosensors exhibit tremendous potential in miRNA detection because they satisfy feature integration, portability, mass production, short response time, and minimal sample consumption. This article reviewed the working principles and signal amplification strategies of electrochemical DNA biosensors summarized the recent improvements. With the development of DNA nanotechnology, nanomaterials and biotechnology, electrochemical DNA biosensors of high sensitivity and specificity for microRNA detection will shortly be commercially accessible.

This study illustrates that 2′-O-methyl modified gRNAs improve the specificity of the CRISPR–Cas12a system (mg-CRISPR) via suppressing the Cas12a's affinity to off-target DNA and provides an efficient strategy for high-specificity gRNA design.

In this article, we consider the problem of adaptive fixed-time tracking control for a class of multiagent systems (MASs) with mismatched uncertainty. Unlike the existing methodologies that only implement the practical finite-/fixed-time stability for MASs, a newly adaptive consensus control criterion is developed to reach fixed-time stability, where the controller design includes a series of newly Lyavonov functions and modified tuning functions. Radial basis function neural networks are employed to deal with the unknown functions in each agent, and the direct adaptive strategy solves the obstacle of ``explosion of complexity.'' Under the performance-oriented controller, the error of the MASs converges to a predetermined interval within a fixed time. Two simulations illustrate the results obtained.

Development of a rapid and effective strategy for the specific detection of hardly degradable pentachlorophenol (PCP) in aqueous phase is of great significance to human health and environmental security. Herein, a fluorescent metalloporphyrin-based metal-organic frameworks (MOFs) sensor of PCN-222(Zn) for PCP sensing was successfully developed, in which Zn-TCPP were simultaneously designed as organic ligands, fluorescent signal reporters and specific recognition sites. Thanks to their high surface area, open structure, exposed active recognition sites as well as excellent chemical stability, a trace amount of PCP in aqueous solutions could be rapidly detected within 30 s. Meanwhile, the fluorescence quenching of MOFs probe exhibited a linear correlation with the PCP level from 80 to 720 ppb and the limit of detection could reach to as low as 33 ppb. Additionally, the PCN-222(Zn) probe could specifically recognize PCP from other structurally similar analogues with a much higher Stern-Volmer quenching constant. The UV–vis and fluorescent lifetime decay spectra demonstrated that the specific recognition might benefit from the formation of a nonfluorecent Zn-TCPP-PCP complex through an axial coordination effect between central zinc atom in porphyrin ring and PCP molecule. The elaborated probe was successfully applied for the real quantitative detection of PCP in the mixed PCP analogues samples, prefiguring the great potentials of the PCN-222(Zn) MOFs probe in PCP pollutant detection.

The boosting exploitation of graphene oxide (GO) increases exposure risk to human beings. However, as the first line defender, neutrophils’ mechanism of defensive behavior towards GO invasion remains unclear. Herein, we discover that neutrophils defensively degrade GO in a lateral dimension dependent manner. The micrometer-sized GO (mGO) induces NETosis by releasing neutrophil extracellular traps (NETs), while nanometer-sized GO (nGO) elicits neutrophil degranulation. The neutrophils’ defensive behavior is accompanied with generation of reactive oxygen species and activation of p-ERK and p-Akt kinases. We unveil that mGO-induced NETosis is NADPH oxidase (NOX)-independent, while nGO-triggered degranulation is NOX-dependent. Furthermore, myeloperoxidase (MPO) is identified to be a determinant mediator despite distinct neutrophil phenotypes in the biodegradation. Neutrophils release NETs comprising of MPO upon activated with mGO, while MPO is secreted via nGO induced-degranulation. Moreover, the binding energy between MPO and GO is calculated to be 69.8728 kJ·mol− 1, which indicates that electrostatic interactions mainly cause the spontaneous binding process in a spatial distance of 9.2 Å. Meanwhile, the central enzymatic biodegradation is found to occur at oxygenic active sites and defects on GO. Mass spectrometry analysis deciphers the degradation products are biocompatible molecules like flavonoids and polyphenols. Our study provides fundamental evidence and practical guidance for functional biomaterial development in sustainable nanotechnology, including but not limited to vaccine adjuvant and drug carrier.

The transparency of the ocular lens is essential for refracting and focusing light onto the retina, and transparency is controlled by many factors and signaling pathways. Here we showed a critical role of chromatin remodeler zinc finger HIT-type containing 1 (Znhit1) in maintaining lens transparency.To explore the roles of Znhit1 in lens development, the cre-loxp system was used to generate lens-specific Znhit1 knockout mice (Znhit1Mlr10-Cre; Znhit1 cKO). Morphological changes in mice lenses were examined using hematoxylin and eosin staining. RNA sequencing (RNA-seq) and assay for transposase accessible chromatin using sequencing (ATAC-seq) were applied to screen transcriptome changes. Immunofluorescence staining were performed to assess proteins distribution and terminal deoxynucleotidyl transferase dUTP nick-end labeling staining were used for determining apoptosis. The mRNAs expression was examined by quantitative RT-PCR and proteins expression by Western blot.Lens-specific conditional knockout mice had a severe cataract, microphthalmia phenotype, and seriously abnormal lens fiber cells differentiation. Deletion of Znhit1 in the lens resulted in decreased cell proliferation and increased cell apoptosis of the lens epithelia. ATAC-seq showed that Znhit1 deficiency increased chromatin accessibility of cyclin-dependent kinase inhibitors, including p57Kip2 and p21Cip1, and upregulated the expression of these genes in mRNA and protein levels. And we also showed that loss of Znhit1 lead to lens fibrosis by upregulating the expression of p21Cip1.Our findings suggested that Znhit1 is required for the survival of lens epithelial cells. The loss of Znhit1 leads to the overexpression of p21Cip1, further resulting in lens fibrosis, and impacted the establishment of lens transparency.

Aiming at the problem of fast and accurate prediction of torsional stiffness of vehicle body, an optimization method based on the simplified model of flexible joint is proposed. Primarily, a simplified model of flexible joint is established by using mathematical model and simulation analysis method. On this basis, an accurate and reliable whole vehicle wire frame model is established by combining with flexible joint and beam element. In the task of new vehicle development, two joints which need to be optimized are positioned quickly by using the model and sensitivity analysis. And then, orthogonal test is designed to calculate the optimization degree of joint stiffness under the optimal cost and weight conditions. The results show that the optimization method based on the simplified model of flexible joints improves the torsional stiffness of the vehicle body by 17%, reduces the cost of components by 12%, and reduces the weight by 0.5 kg compared with the traditional method, which achieves the effect of improving the quality and reducing the cost.

High throughput DNA sequencing in combination with efficient algorithms could provide the basis for a highly resolved, genome phylogeny-based and digital prokaryotic taxonomy. However, current taxonomic practice continues to rely on cumbersome journal publications for the description of new species, which still constitute the smallest taxonomic units. In response, we introduce LINbase, a web server that allows users to genomically circumscribe any group of prokaryotes with measurable DNA similarity and that uses the individual isolate as smallest unit. Since LINbase leverages the concept of Life Identification Numbers (LINs), which are codes assigned to individual genomes based on reciprocal average nucleotide identity, we refer to groups circumscribed in LINbase as LINgroups. Users can associate with each LINgroup a name, a short description, and a URL to a peer-reviewed publication. As soon as a LINgroup is circumscribed, any user can immediately identify query genomes as members and submit comments about the LINgroup. Most genomes currently in LINbase were imported from GenBank, but users can upload their own genome sequences as well. In conclusion, LINbase combines the resolution of LINs with the power of crowdsourcing in support of a highly resolved, genome phylogeny-based digital taxonomy. LINbase is available at http://www.LINbase.org. National Science Foundation [IOS-1354215, in part]; College of Agriculture and Life Sciences, Virginia Polytechnic Institute and State University; Virginia Agricultural Experiment Station (to B.A.V.) (in part); Hatch Program of the National Institute of Food and Agriculture, US Department of Agriculture (to B.A.V.). Funding for open access charge: National Science Foundation; Institutional Funds.

The boosting exploitation of graphene oxide (GO) increases exposure risk to human beings. However, as primary defender in the first immune line, neutrophils' mechanism of defensive behavior towards GO remains unclear. Herein, we discover that neutrophils recognize and defensively degrade GO in a lateral dimension dependent manner. The micrometer-sized GO (mGO) induces NETosis by releasing neutrophil extracellular traps (NETs), while nanometer-sized GO (nGO) elicits neutrophil degranulation. The two neutrophils' defensive behaviors are accompanied with generation of reactive oxygen species and activation of p-ERK and p-Akt kinases. We unveil that mGO-induced NETosis is NADPH oxidase (NOX)-independent while nGO-triggered degranulation is NOX-dependent. Furthermore, myeloperoxidase (MPO) is identified to be a determinant mediator despite distinct neutrophil phenotypes in the biodegradation. Neutrophils release NETs comprising of MPO upon activated with mGO, while MPO is secreted via nGO induced-degranulation. Moreover, the binding energy between MPO and GO is calculated to be 69.8728 kJ·mol-1 , which indicates that electrostatic interactions mainly cause the spontaneous binding process in a spatial distance of 9.2 A. Meanwhile, the central enzymatic biodegradation is found to occur at oxygenic active sites and defects on GO. Mass spectrometry analysis deciphers the degradation products are biocompatible molecules like flavonoids and polyphenols. Our study provides fundamental evidence and practical guidance for nanotechnology based on GO, including but not limited to vaccine adjuvant, implantable devices and energy storage. This article is protected by copyright. All rights reserved.

Mass cytometry, also called cytometry by time-of-flight (CyTOF), is an emerging powerful proteomic analysis technique that utilizes metal chelated polymer (MCP) as mass tags for interrogating high-dimensional biomarkers simultaneously on millions of individual cells. However, under the typical polymer-based mass tag system, the sensitivity and multiplexing detection ability has been highly restricted. Herein, a new structure mass tag based on a nanometal organic framework (NMOF) is reported for multiparameter and sensitive single-cell biomarker interrogating in CyTOF. A uniform-sized Zr-NMOF (33 nm) carrying 105 metal ions is synthesized under modulator/reaction time coregulation, which is monodispersed and colloidally stable in water for over one-year storage. On functionalization with an antibody, the Zr mass tag exhibits specific molecular recognition properties and minimal cross-reaction toward nontargeted cells. In addition, the Zr-mass tag is compatible with MCP mass tags in a multiparameter assay for mouse spleen cells staining, which exploits four additional channels, m/z = 90, 91, 92, 94, for single-cell immunoassays in CyTOF. Compared to the MCP mass tag, the Zr-mass tag provides an additional fivefold signal amplification. This work provides the fundamental technical capability for exploiting NMOF-based mass tags for CyTOF application, which opens up possibility of high-dimensional single-cell immune profiling, low abundant antigen detection, and development of new barcoding systems.

Nowadays, the main obstacle for further miniaturization and integration of nucleic acids point‐of‐care testing devices is the lack of low‐cost and high‐performance heating materials for supporting reliable nucleic acids amplification. Herein, reduced graphene oxide hybridized multi‐walled carbon nanotubes nano‐circuit integrated into an ingenious paper‐based heater is developed, which is integrated into a paper‐based analytical device (named HiPAD). The coronavirus disease 2019 (COVID‐19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) is still raging across the world. As a proof of concept, the HiPAD is utilized to visually detect the SARS‐CoV‐2 N gene using colored loop‐mediated isothermal amplification reaction. This HiPAD costing a few dollars has comparable detection performance to traditional nucleic acids amplifier costing thousands of dollars. The detection range is from 25 to 2.5 × 1010 copies mL−1 in 45 min. The detection limit of 25 copies mL−1 is 40 times more sensitive than 1000 copies mL−1 in conventional real‐time PCR instruments. The disposable paper‐based chip could also avoid potential secondary transmission of COVID‐19 by convenient incineration to guarantee biosafety. The HiPAD or easily expanded M‐HiPAD (for multiplex detection) has great potential for pathogen diagnostics in resource‐limited settings., rGO/MWCNTs are first developed into rGO/MWCNTs nano‐circuit heaters as cheap, easy‐to‐use, and flexible electrothermal modules for nucleic acid testing point‐of‐care testing devices. The miniaturized rGO/MWCNTs heater integrated paper‐based analytical device can visually detect SARS‐CoV‐2 with 25 copies mL−1 of detection limit based on colored LAMP reaction in 45 min.

Optimal modification and gelation strategies of polysaccharide hydrogels have been developed for biomedical applications. Herein, a kind of fast crosslinking alginate hydrogel with superior gel properties was prepared for the first time combining dual crosslinking mechanisms. Firstly, sodium alginate (SA) was modified by vinyl ether side chains through one-step amidation reaction with aminopropyl vinyl ether (APVE) catalyzed by EDC/NHS. Just within 10 s, the grafting product of SA-VE was demonstrated to form hydrogen bonded hydrogel SA-VE/H2O spontaneously. Based on this mechanism, a dual crosslinking alginate hydrogel SA-VE/DTT was fabricated through introducing thiol-ene click chemistry reaction with dithiothreitol (DTT) under UV exposure. According to rheological results, the photo-crosslinking process was completed within 5–9 min. Combining hydrogen bonding and thiol-ene click chemistry, the dual crosslinking mechanism was proved to bring the hydrogel system not only fast gelation but also superior storage modulus up to 13373 Pa and excellent stability of over 1 month. All the hydrogels exhibited non-cytotoxicity towards NIH-3T3 fibroblasts. Furthermore, the 26 s rapid hemostasis behavior of SA-VE exhibited in rat tail hemostasis experiment reveals its potential application in wound dressing materials.

Quadrotor UAVs equipped with lidar have an indispensable role in forestry production. In this paper, an autonomous quadrotor with autonomous guidance and navigation ability is designed. Karto Slam algorithm for forestry quadrotor is utilized to accomplish the mission of situation awareness, in which the SPA method and the LM algorithm are used to make the map constructed in practical application with good accuracy and closed-loop characteristics. The RRT* algorithm is used to acquire the sub-optimal path further. The results show that the system can accomplish the task well in the presence of a large number of tree obstacles and has lower computational complexity.

Blue-and-white porcelain is a kind of famous underglaze color porcelain in Chinese ceramic history. In this paper, 13 pieces of blue-and-white porcelain shards collected in Beijing were adopted as samples. Microstructure characteristics and distributions of chemical elements were investigated. Quartz and mullite were the main crystalline phases in blue-and-white porcelain bodies. The column-like crystals in the glaze were anorthite crystals. Microstructures of interaction layers in the blue decorations could be divided into two categories with morphologically distinctive microstructures: column-like and flower-like structures. The coloring elements surrounded by dense anorthite crystals mainly concentrated in the center of interaction layers, and the cobalt blue pigments were identified as cobalt aluminate (CoAl2O4).

The gray of two images of a same particle taken by a digital camera with different exposure times is different too. Based on the gray difference of particle images in a double-exposed photo and ai]tocorrelation processing of digital images, this paper proposes a method for measuring particle velocities and sizes simultaneously. This paper also introduces the theoretical foundation of this method, the process of particle imaging and image processing, and the simultaneous measurement of velocity and size of a low speed flow field with 35 μm and 75 μm standard particles. The graphical measurement results can really reflect the flow characteristics of the flow field. In addition, although the measured velocity and size histograms of these two kinds of standard particles are slightly wider than the theoretical ones, they are all still similar to the normal distribution, and the peak velocities and diameters of the histograms are consistent with the defai]lt values. Therefore, this measurement method is capable of providing moderate measurement accuracy, and it can be further developed for high-speed flow field measurements.

Natural sensory stimuli frequently consist of a fine structure whose amplitude (i.e. envelope) varies more slowly. Previous studies have demonstrated that envelope signals are found across sensory systems and are necessary for perception. For example, envelope signals in the auditory system carry information pertaining to the perception of pitch fluctuations in communication vocalizations [1], while envelopes in the visual system are responsible for object grouping and the perception of illusory contours [2,3]. However, the neural mechanisms underlying the encoding of these envelope signals are poorly understood in general. Gymnotiform wave-type weakly electric fish constitute an attractive model system for studying envelope processing in the brain because of its well-characterized anatomy and physiology [4]. These fish generate around themselves a weak quasi-sinusoidal electric field through the electric organ discharge (EOD) [5]. Recent studies have shown that the beat amplitude (i.e. the envelope) can vary in time during different behavioral contexts and display differential frequency content: while envelopes caused by movement primarily contain low ( 1 Hz) temporal frequencies [7]. While it is known that electrosensory neurons can respond to envelopes [7], whether these neurons respond differentially to envelopes arising from movement and social interaction is unknown in part because their tuning to envelope frequencies has not been characterized. Here we used well established techniques [8] to record from electrosensory pyramidal neurons across different maps of the body surface within the electrosensory lateral line lobe (ELL) in response to envelope stimuli with different frequency content spanning the behaviorally relevant range (0.05-10 Hz). Using standard measures of linear systems identification techniques as well as more quantitative methods of information theory, we found that pyramidal neurons in different maps displayed differential responses to envelopes arising from different behavioral contexts. Our results suggest that information about envelopes arising from different behavioral contexts begins to be segregated at the level of the ELL and provide new insights as to how these behaviorally relevant stimuli are encoded in early sensory pathways.