Dissipative Kerr soliton generation using self-injection-locked III-V lasers has enabled fully integrated hybrid microcombs that operate in turnkey mode and can access microwave repetition rates. ...Yet, continuous-wave-driven soliton microcombs exhibit low energy conversion efficiency and high optical power threshold, especially when the repetition frequencies are within the microwave range that is convenient for direct detection with off-the-shelf electronics. Here, by actively switching the bias current of injection-locked III-V semiconductor lasers with switching frequencies in the X-band and K-band microwave ranges, we pulse-pump both crystalline and integrated microresonators with picosecond laser pulses, generating soliton microcombs with stable repetition rates and lowering the required average pumping power by one order of magnitude to a record-setting level of a few milliwatts. In addition, we unveil the critical role of the phase profile of the pumping pulses, and implement phase engineering on the pulsed pumping scheme, which allows for the robust generation and the stable trapping of solitons on intracavity pulse pedestals. Our work leverages the advantages of the gain switching and the pulse pumping techniques, and establishes the merits of combining distinct compact comb platforms that enhance the potential of energy-efficient chipscale microcombs.
Little is known about the sediment delivery of single flood events although it has been well known that the sediment delivery ratio at the inter-annual time scale is close to 1 in the Chinese Loess ...Plateau. This study examined the sediment delivery of single flood events and the influencing factors in a headwater basin of the Loess Plateau, where hyperconcentrated flows are dominant. Data observed from plot to subwatershed over the period from 1959 to 1969 were presented. Sediment delivery ratio of a single event (SDRe) was calculated as the ratio of sediment output from the subwatershed to sediment input into the channel. It was found that SDRe varies greatly for small events (runoff depth <5 mm or rainfall depth <30 mm) and remains fairly constant (approximately between 1.1 and 1.3) for large events (runoff depth >5 mm or rainfall depth >30 mm). We examined 11 factors of rainfall (rainfall amount, rainfall intensity, rainfall kinetic energy, rainfall erosivity and rainfall duration), flood (area-specific sediment yield, runoff depth, peak flow discharge, peak sediment concentration and flood duration) and antecedent land surface (antecedent precipitation) in relation to SDRe. Only the peak sediment concentration significantly correlates with SDRe. Contrary to popular belief, channel scour tends to occur in cases of higher peak sediment concentrations. Because small events also have chances to attain a high sediment concentration, many small events (rainfall depth <20 mm) are characterized by channel scour with an SDRe larger than 1. Such observations can be related to hyperconcentrated flows, which behave quite differently from normal stream flows. Our finding that large events have a nearly constant SDRe is useful for sediment yield predictions in the Loess Plateau and other regions where hyperconcentrated flows are well developed.
Polyethylene oxide (PEO)-based solid polymer electrolyte (SPE) is considered to have great application prospects in all-solid-state li-ion batteries. However, the application of PEO-based SPEs is ...hindered by the relatively low ionic conductivity, which strongly depends on its crystallinity and density of grain boundaries. In this work, a simple and effective press-rolling method is applied to reduce the crystallinity of PEO-based SPEs for the first time. With the rolled PEO-based SPE, the LiFePO
4
/SPE/Li all-solid li-ion battery delivers a superior rechargeable specific capacity of 162.6 mAh g
−1
with a discharge-charge voltage gap of 60 mV at a current density of 0.2
C
with a much lower capacity decay rate. The improvement of electrochemical properties can be attributed to the press-rolling method, leading to a doubling conductivity and reduced activation energy compared with that of electrolyte prepared by traditional cast method. The present work provides an effective and easy-to-use grain reforming method for SPE, worthy of future application.
Numerous endeavors have been undertaken to gain enhanced upconversion luminescence via surface plasmon resonance (SPR) generated by specially designed nanostructures of noble metals (e.g., Au, Ag). ...However, the SPR response of these metals is usually weak in the ultraviolet (UV) region because of their intrinsic electronic configurations; thus, only green and red upconversion emissions can undergo significant plasmonic enhancement yet without selectivity, while an efficient approach to selectively enhancing the blue upconversion luminescence has been lacking. Herein, by integrating the pronounced UV SPR of silica‐coated indium nanocrystals (InNCs) with blue‐emission upconversion nanoparticles (UCNPs) of NaYbF4:Tm, an up to tenfold selective luminescence enhancement at 450 nm is obtained upon 980 nm laser excitation. Precise manipulation of the silica shell thickness suggests an optimal working distance of 3 nm between InNCs and UCNPs. This study has, for the first time, realized selective blue upconversion luminescence enhancement by using an inexpensive, non‐noble metal material, which will not only enrich the fundamental investigations of SPR‐enhanced upconversion emission, but also widen the applications of blue light‐emitting nanomaterials, for example, in therapeutics.
Taking advantage of the ultraviolet surface plasmon resonance of indium nanocrystals (InNCs), an up to tenfold selective enhancement of blue upconversion luminescence of NaYbF4:Tm nanoparticles (UCNPs) at 450 nm is realized, by assembling InNCs outside the UCNPs separated by an optimized 3 nm silica shell.
Cyclic GMP-AMP synthase (cGAS) plays a key role in the innate immune responses to both DNA and RNA virus infection. Here, we found that enterovirus 71 (EV-A71), Seneca Valley virus (SVV), and ...foot-and-mouth disease virus (FMDV) infection triggered mitochondria damage and mitochondrial DNA (mtDNA) release in vitro and vivo. These responses were mediated by picornavirus 2B proteins which induced mtDNA release during viral replication. SVV infection caused the opening of mitochondrial permeability transition pore (mPTP) and led to voltage-dependent anion channel 1 (VDAC1)- and BCL2 antagonist/killer 1 (Bak) and Bak/BCL2-associated X (Bax)-dependent mtDNA leakage into the cytoplasm, while EV-A71 and FMDV infection induced mPTP opening and resulted in VDAC1-dependent mtDNA release. The released mtDNA bound to cGAS and activated cGAS-mediated antiviral immune response. cGAS was essential for inhibiting EV-A71, SVV, and FMDV replication by regulation of IFN-β production. cGAS deficiency contributed to higher mortality of EV-A71- or FMDV-infected mice. In addition, we found that SVV 2C protein was responsible for decreasing cGAS expression through the autophagy pathway. The 9th and 153rd amino acid sites in 2C were critical for induction of cGAS degradation. Furthermore, we also show that EV-A71, CA16, and EMCV 2C antagonize the cGAS-stimulator of interferon genes (STING) pathway through interaction with STING, and highly conserved amino acids Y155 and S156 were critical for this inhibitory effect. In conclusion, these data reveal novel mechanisms of picornaviruses to block the antiviral effect mediated by the cGAS-STING signaling pathway, which will provide insights for developing antiviral strategies against picornaviruses.
Photonic chip-based soliton microcombs have shown rapid progress and have already been used in many system-level applications. There has been substantial progress in realizing soliton microcombs that ...rely on compact laser sources, culminating in devices that only utilize a semiconductor gain chip or a self-injection-locked laser diode as the pump source. However, generating single solitons with electronically detectable repetition rates from a compact laser module has remained challenging. Here we demonstrate a current-initiated, Si
N
chip-based, 99-GHz soliton microcomb driven directly by a compact, semiconductor-based laser. This approach does not require any complex soliton tuning techniques, and single solitons can be accessed by tuning the laser current. Further, we demonstrate a generic, simple, yet reliable, packaging technique to facilitate the fiber-chip interface, which allows building a compact soliton microcomb package that can benefit from the fiber systems operating at high power (> 100 mW). Both techniques can exert immediate impact on chip-based nonlinear photonic applications that require high input power, high output power, and interfacing chip-based devices to mature fiber systems.
Non-ionic surfactant micelles are helpful for improving the diffusion of topically delivered drugs through the cornea. This study aimed to develop terbinafine hydrochloride (TH)-loaded micelles based ...on a soft non-ionic surfactant-macrogol 15 hydroxystearate (HS 15) and to investigate their in vivo cornea permeation. Briefly, 0.25% TH-loaded HS 15 micelles (TH-HNMs) were developed using a simple co-solvent method. Characterization of the TH-HNMs by Zetasizer and transmission electron microscopy (TEM) revealed that the spherical and discrete micellar droplets with a small size (13.22±0.73nm) and an electrically neutral surface (−2.15±0.39mV) were achieved. The drug entrapment efficiency of TH-HNMs was almost 100%. The release of TH from the micelles was pH dependent. 93.2±3.4% of encapsulated TH was released from the micelles in the PBS at pH5.0 within 6h, but only 0.122±0.020% of encapsulated TH was released in the PBS at pH7.4 within the same release time. TH-HNMs possessed good physical stability in the pH neutral medium (pH7.0).No obvious irritations were observed in rabbit eyes after ocular instillation of TH-HNMs. The in vivo corneal permeation study revealed that the TH-HNMs can penetrate into the corneal epithelium quickly and efficiently in mouse eyes. Good permeability was also noted in the stroma of mouse corneas with de-epithelialization. Compared with the TH oily solution, TH-HNMs delivered considerably increased levels of TH into rabbit corneas with or without de-epithelialization. In conclusion, the easily prepared, small, physically stable and biocompatible TH-HNMs with good ocular bioavailability hold great promise as an efficient carrier for topical ocular delivery of TH.
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Currently, the world is in a period of urbanization that will accelerate the processes of land-use cover and ecological change. Thus, establishing a land-use and land-cover change (LUCC) prediction ...and simulation model is of great significance for understanding the process of urban change and assessing its ecological impact. In previous studies, LUCC prediction models have been mainly based on cellular automata structures that calculate a future state pixel by pixel through transition rules. Because these transition rules are usually based on the global state and each pixel is calculated according to these fixed rules, the results of these methods have room for improvement in terms of generating details and heterogeneity. In this article, a generative adversarial network (GAN)-based LUCC prediction model using multiscale local spatial information is proposed. The model is based on a pix2pix GAN and an attention structure that predicts future land use through multiscale local spatial information. To validate our model, Shenzhen, a region that is experiencing rapid urbanization, was chosen as the source of the experimental data. The results indicate that the proposed method achieved the highest accuracy in both short-time interval and long-time interval scenarios. In addition, the results of the proposed method were also closest to the ground truth from the perspective of the landscape pattern.
The soils of the Loess Plateau of China exhibit zonal characteristics, with declining clay percentages from the southern to northern regions. However, these differences have been largely ignored in ...studies of soil erosion and the related organic carbon (OC) loss. The goal of this study was to investigate the effect of gradual changes in soil texture on the loss and selective transport of soil and soil organic carbon (SOC) on the Loess Plateau of China. Four typical soils with decreasing clay contents (26.3%, 21.2%, 15.6% and 12.1%) in Shaanxi Province were selected and studied. Rainfall-simulated experiments were performed in 1m (width)×5m (length) plots with a rainfall intensity of 120mmh−1 on three slope gradients (15°, 20° and 25°). The runoff and sediment yields, particle size distributions of the sediments, OC concentrations and enrichment ratios of OC in sediment (ERoc) during rainfall processes were measured and calculated. A comparison of the rainfall characteristics between rainfall events in different soils indicated that a decrease in the clay percentage increased the intensity of rill erosion. The runoff rates of different events decreased with the clay percentage, whereas no general pattern was observed in the sediment yield rate due to differences in the initial timing and intensity of rill erosion. Furthermore, the ERoc values in the sediments of all the events were between 0.64 and 1.44, with 90% of values between 0.80 and 1.20. Similarly, the effective particle size distribution of the sediments exhibited relatively constant values with rainfall duration. Non-significant correlations (P>0.05) between ERoc and dispersed and non-dispersed sediment particles suggested that the transport of sediment and OC was non-selective. Moreover, significant linear correlations were observed between the amount of SOC loss and sediments in all the events. However, there was no significant difference in total SOC loss between the rainfall events, except for in events with a soil clay percentage of 15.6%. SOC losses in soils with 26.3% and 21.2% clay percentages were mainly due to the high SOC concentrations of the original soils, whereas those in other soils were due to the large amount of lost sediment. However, the variations in soil loss and SOC loss were not associated with changes in the clay content of the soil. These results suggest that zonal soils with decreasing clay contents do not influence the selective transport of OC, but soil textures affect the sediment and SOC loss through complicated mechanisms.
•Effects of zonal soils on SOC loss and selective transportation were studied.•Temporal changes in ERoc reflected non-selective OC transport.•No significant difference in the amount of SOC loss was observed between most rainfall events.•SOC loss amount for high (low) clay content soil is controlled by OC content (soil loss).
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