We present single-cell interpretation via multikernel learning (SIMLR), an analytic framework and software which learns a similarity measure from single-cell RNA-seq data in order to perform ...dimension reduction, clustering and visualization. On seven published data sets, we benchmark SIMLR against state-of-the-art methods. We show that SIMLR is scalable and greatly enhances clustering performance while improving the visualization and interpretability of single-cell sequencing data.
Carbon dots (CDots), an emerging class of photoluminescent materials, exhibit excellent optical, electrical and chemical properties with many potential applications. Hetero-atom doping in CDots ...represents a robust and versatile technique to further improve the chemical composition and structure properties of CDots. In this review, we provide an updated roadmap of the hetero-atom-doped CDots. Various up-to-date synthetic strategies, starting with different raw materials to synthetic methods to doping elements, are surveyed. Furthermore, the catalysis, optical properties, biological properties and the potential applications of hetero-atom doped CDots, including nano-probes, optoelectronic devices, catalysis, and biomedicine are also reviewed. We further provide an outlook towards future developments of the hetero-atom-doped CDots. This review will provide a summary of the latest progress of hetero-atom-doped CDots and is expected to inspire further developments in this exciting class of materials.
Particle focusing in microfluidic devices Xuan, Xiangchun; Zhu, Junjie; Church, Christopher
Microfluidics and nanofluidics,
07/2010, Letnik:
9, Številka:
1
Journal Article
Recenzirano
Focusing particles (both biological and synthetic) into a tight stream is usually a necessary step prior to counting, detecting, and sorting them. The various particle focusing approaches in ...microfluidic devices may be conveniently classified as sheath flow focusing and sheathless focusing. Sheath flow focusers use one or more sheath fluids to pinch the particle suspension and thus focus the suspended particles. Sheathless focusers typically rely on a force to manipulate particles laterally to their equilibrium positions. This force can be either externally applied or internally induced by channel topology. Therefore, the sheathless particle focusing methods may be further classified as active or passive by the nature of the forces involved. The aim of this article is to introduce and discuss the recent developments in both sheath flow and sheathless particle focusing approaches in microfluidic devices.
SiC particle reinforced Al matrix composites are increasingly applied in the automotive, military, aerospace and electronic encapsulation fields. In this work, SiC particle reinforced AlSi10Mg ...composites were fabricated by selective laser melting (SLM). The influences of processing parameters, such as laser power, hatching space and scanning speed, on density, microstructure and mechanical properties of the SLMed SiCp/AlSi10Mg composites were investigated systematically. Under the optimal processing parameters, 97.7% relative density of the SLMed composites was achieved. The SiC particles were distributed uniformly in AlSi10Mg matrix. The decomposition of SiC particles occurred during the SLM processing, and there was a reduction tendency of the SiC particle as the laser energy input increased. The microstructure was characterized by optical microscope, scanning electron microscope and X-ray diffraction. Due to the interfacial chemical reaction between SiC and the aluminum matrix, several the reaction products of the needle-shaped phases Al4SiC4 and faceted particles Si were formed, which dispersed in the primary α-Al dendrites and α-Al + Si eutectic matrix. The continuous and compatible chemical interface between the SiC particles and the matrix were found with no micro-pores or micro-cracks. Compared with the SLMed AlSi10Mg, the microhardness of the SLMed SiCp/AlSi10Mg composites (217.4HV0.2) increased, but the tensile strength (341.9 MPa) decreased obviously. The fracture mode of the SLMed composites was mainly brittle fracture. The main reasons for the early failure of the SLMed SiCp/AlSi10Mg composites were the existence of the pores in the aluminum matrix and the SiC particle cracking. At last, a thin-wall part with complicated structure made of 15 wt% SiCp/AlSi10Mg was fabricated successfully.
To deal with the uncertain relationship between random variables and harmonic spectrum in existing random pulse width modulation, this paper links the uniformly distributed random carrier sequence ...(RCS) probabilistic parameters with harmonic distributed in the frequency domain, offers an approach to selecting a random carrier sequence. Based on random slope PWM (RSPWM), the formula for 3-dB bandwidth of harmonic power spectrum is deduced. Then some useful conclusions are also drawn under random carrier sequence obeying uniform distribution. The 3-dB bandwidth formula leads to a method of selecting the main probability statistical parameters. The method has laid a theoretical foundation for the design and selection of random variables in random PWM, provided scientific reference for the study of random PWM technology which is used to reduce electromagnetic interference and mechanical vibration.
Developing porous carbon-based non-precious-metal catalysts for an oxygen reduction reaction (ORR) is a suitable approach to significantly reduce the costs of fuel cells or metal–air batteries. ...Herein, interconnected hierarchically porous carbon nanofibers simultaneously doped with nitrogen and iron (HP-Fe-N/CNFs) were fabricated by facile pyrolysis of polypyrrole-coated electrospun polystyrene/FeCl3 fibers. The obtained carbon nanofibers have a high specific surface area (569.6 m2/g) and large pore volume (1.00 cm3/ g) as well as effective doping of N and Fe. Benefiting from the improved mass transfer and utilization of active sites attributed to interconnected hierarchical porous structures, HP-Fe-N/CNFs display excellent ORR catalytic activity in alkaline media, with a comparable onset potential and half-wave potential but superior selectivity, stability, and tolerance against methanol to commercial 30 wt % Pt/C. Particularly, when applied in an assembled Zn–air battery, HP-Fe-N/CNFs outperform 30 wt % Pt/C in power density and long-term stability, explicitly showing their promising practical application.
Spinal cord injury in mammals is thought to trigger scar formation with little regeneration of axons
. Here we show that a crush injury to the spinal cord in neonatal mice leads to scar-free healing ...that permits the growth of long projecting axons through the lesion. Depletion of microglia in neonatal mice disrupts this healing process and stalls the regrowth of axons, suggesting that microglia are critical for orchestrating the injury response. Using single-cell RNA sequencing and functional analyses, we find that neonatal microglia are transiently activated and have at least two key roles in scar-free healing. First, they transiently secrete fibronectin and its binding proteins to form bridges of extracellular matrix that ligate the severed ends of the spinal cord. Second, neonatal-but not adult-microglia express several extracellular and intracellular peptidase inhibitors, as well as other molecules that are involved in resolving inflammation. We transplanted either neonatal microglia or adult microglia treated with peptidase inhibitors into spinal cord lesions of adult mice, and found that both types of microglia significantly improved healing and axon regrowth. Together, our results reveal the cellular and molecular basis of the nearly complete recovery of neonatal mice after spinal cord injury, and suggest strategies that could be used to facilitate scar-free healing in the adult mammalian nervous system.
Networks are ubiquitous in biology where they encode connectivity patterns at all scales of organization, from molecular to the biome. However, biological networks are noisy due to the limitations of ...measurement technology and inherent natural variation, which can hamper discovery of network patterns and dynamics. We propose Network Enhancement (NE), a method for improving the signal-to-noise ratio of undirected, weighted networks. NE uses a doubly stochastic matrix operator that induces sparsity and provides a closed-form solution that increases spectral eigengap of the input network. As a result, NE removes weak edges, enhances real connections, and leads to better downstream performance. Experiments show that NE improves gene-function prediction by denoising tissue-specific interaction networks, alleviates interpretation of noisy Hi-C contact maps from the human genome, and boosts fine-grained identification accuracy of species. Our results indicate that NE is widely applicable for denoising biological networks.
Fault diagnosis is essential for high energy systems such as liquid rocket engines (LREs) due to harsh thermal and mechanical working environment. In this study, a novel method based on one-dimension ...Convolutional Neural Network (1D-CNN) and interpretable bidirectional Long Short-term Memory (LSTM) is proposed for intelligent fault diagnosis of LREs. 1D-CNN is responsible for extracting sequential signals collected from multi sensors. Then the interpretable LSTM is developed to model the extracted features, which contributes to modeling the temporal information. The proposed method was executed for fault diagnosis using the simulated measurement data of the LRE mathematical model. The results demonstrate the proposed algorithm outperforms other methods in terms of accuracy of fault diagnosis. Through experimental verification, the method proposed in this paper was compared with CNN, 1DCNN-SVM and CNN-LSTM in terms of LRE startup transient fault recognition performance. The model proposed in this paper had the highest fault recognition accuracy (97.39%).
Many human spinal cord injuries are anatomically incomplete but exhibit complete paralysis. It is unknown why spared axons fail to mediate functional recovery in these cases. To investigate this, we ...undertook a small-molecule screen in mice with staggered bilateral hemisections in which the lumbar spinal cord is deprived of all direct brain-derived innervation, but dormant relay circuits remain. We discovered that a KCC2 agonist restored stepping ability, which could be mimicked by selective expression of KCC2, or hyperpolarizing DREADDs, in the inhibitory interneurons between and around the staggered spinal lesions. Mechanistically, these treatments transformed this injury-induced dysfunctional spinal circuit to a functional state, facilitating the relay of brain-derived commands toward the lumbar spinal cord. Thus, our results identify spinal inhibitory interneurons as a roadblock limiting the integration of descending inputs into relay circuits after injury and suggest KCC2 agonists as promising treatments for promoting functional recovery after spinal cord injury.
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•A KCC2 agonist restores stepping ability in paralyzed mice with spinal cord injuries•KCC2 expression in inhibitory neurons leads to functional recovery•Restoration of inhibition in injured spinal cord leads to functional recovery
Reducing the excitability of spinal cord inhibitory interneurons with a small molecule enhances the injured spinal cord’s responsiveness to descending inputs and promotes functional recovery after spinal cord injury in mice.
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