Water-based synthesis of nanoscale hierarchical metal-organic frameworks:Boosting adsorption and catalytic performance

The combination of nano sizes,large pore sizes and green synthesis is recognized as one of the most crucial and challenging problems in constructing metal-organic frameworks(MOFs).Herein,a water-based strategy is proposed for the synthesis of nanoscale hierarchical MOFs(NH-MOFs)with high crystallinity and excellent stability.This approach allows the morphology and porosity of MOFs to be fine tuned,thereby enabling the nanoscale crystal generation and a well-defined hierarchical system.The aqueous solution facilitates rapid nucleation kinetics,and the introduced modulator acts as a deprotonation agent to accelerate the deprotonation of the organic ligand as well as a structure-directing agent(SDA)to guide the formation of hierarchical networks.The assynthesized NH-MOFs(NH-ZIF-67)were assessed as efficient adsorbents and heterogeneous catalysts to facilitate the diffusion of guest molecules,outperforming the parent microZIF-67.This study focuses on understanding the NH-MOF growth rules,which could allow tailor-designing NH-MOFs for various functions.

Near-field triggering of microearthquakes along the Longitudinal Valley fault in eastern Taiwan

Dynamic earthquake triggering as a well-documented phenomenon can provide valuable information for studying the stress loading cycle from failure on faults.In this study,seismicity rate changes were investigated in the Longitudinal Valley fault(LVF)following the 2019 M_(L)5.2 Hualien earthquake,which occurred offshore in eastern Taiwan.After the matched filter technique was applied to continuous waveform data,twice as many microearthquakes were newly detected in the vicinity of the LVF compared with the number listed in the Taiwan Weather Bureau catalog.Seismicity rates in the northern segment of the LVF increased immediately following the Hualien mainshock,which indicated dynamic triggering during the passage of seismic waves.Statistical analysis suggested that following seismic events might be attributed to fault slipping or creeping.These findings show that the observation of earthquake triggering can provide valuable assistance in monitoring the stress perturbations of active faults.

EXISTENCE OF GLOBAL L~∞ SOLUTIONS TO A GENERALIZED n × n HYPERBOLIC SYSTEM OF LEROUX TYPE

In this article, we give the existence of global L∞bounded entropy solutions to the Cauchy problem of a generalized n × n hyperbolic system of Le Roux type. The main difficulty lies in establishing some compactness estimates of the viscosity solutions because the system has been generalized from 2×2 to n×n and more linearly degenerate characteristic fields emerged, and the emergence of singularity in the region {v1= 0} is another difficulty.We obtain the existence of the global weak solutions using the compensated compactness method coupled with the construction of entropy-entropy flux and BV estimates on viscous solutions.

The Prediction of the Peak Time of People Taking School Bus Based on Martingale Process

As the main tool for students and professors to come and go to different districts in-campus, the school bus is of great importance. In order to improve its efficiency and convenient students and professors, a rational schedule of departure is badly needed. A model is established to predict the peak time of people taking school bus based on martingale process, and it is solved according to stopping time of martingale. Then it is applied to Wuhan University of Technology. A large amount of data is collected and the peak time for each day is predicted combined with the actual situation of the college. In doing so, suggestions are given for those who are in charge of the school buses.

Modularized sulfur storage achieved by 100% space utilization host for high performance lithium-sulfur batteries

Popularization of lithium-sulfur batteries(LSBs) is still hindered by shuttle effect and volume expansion.Herein, a new modularized sulfur storage strategy is proposed to solve above problems and accomplished via employing 100% space utilization host material of cobalt loaded carbon nanoparticles derived from ZIF-67. The modular dispersed storage of sulfur not only greatly increases the proportion of active sulfur,but also inhibits the occurrence of volume expansion. Meanwhile, 100% space utilization host material can greatly improve the conductivity of the cathode, provide a larger electrolyte wetting interface and effectively suppress the shuttle effect. Moreover, loaded cobalt particles have high catalytic activity for electrochemical reaction and can effectively improve the redox kinetics. The cell with new cathode host material carbonized at 650 ℃(ZIF-67(650 ℃)) exhibits superior rate performance and can maintain a high specific capacity of 950 m Ah/g after 100 cycles at 0.2 C, showing a good cycle stability.

Response of soil microbial activities and ammonia oxidation potential to environmental factors in a typical antimony mining area

Mining,smelting and tailing deposition activities can cause metal(loid)contamination in surrounding soils,threatening ecosystems and human health.Microbial indicators are sensitive to environmental factors and have a crucial role in soil ecological risk assessment.Xikuangshan,the largest active antimony(Sb)mine in the world,was taken as the research area.The soil properties,metal(loid)contents and microbial characteristics were investigated and their internal response relationships were explored by multivariate statistical analysis.The assessment of the single pollution index and Nemerow synthetic pollution index(PN)showed that the soils were mainly polluted by Sb,followed by Cd and As,in which sampling site S1 had a slight metal(loid)pollution and the other sampling sites suffered from severe synthetic metal(loid)pollution.The microbial characteristics were dissimilar among sampling points at different locations from the mining area according to hierarchical cluster analysis.The correlation analysis indicated that fluorescein diacetate hydrolase,acid phosphatase,soil basal respiration andmicrobial biomass carbonwere negatively correlatedwith PN,indicating their sensitivity to combined metal(loid)contamination;that dehydrogenase was positively correlated with pH;and that urease,potential ammonia oxidation and abundance of ammonia-oxidizing bacteria and archaea were correlated with N(nitrogen)contents.However,β-glucosidase activity had no significant correlations with physicochemical properties and metal(loid)contents.Principal components analysis suggested bioavailable Sb and pH were the dominant factors of soil environment in Xikuangshan Sb mining area.Our results can provide a theoretical basis for ecological risk assessment of contaminated soil.

Infection of SARS-CoV-2 causes severe pathological changes in mouse testis

Coronavirus disease 2019(COVID-19),caused by severe acute respiratory syndrome coronavirus 2(SARSCoV-2),has affected more than 600 million people worldwide.Several organs including lung,intestine,and brain are infected by SARS-CoV-2.It has been reported that SARS-CoV-2 receptor angiotensin-converting enzyme-2(ACE2)is expressed in human testis.However,whether testis is also affected by SARS-CoV-2 is still unclear.In this study,we generate a human ACE2(hACE2)transgenic mouse model in which the expression of hACE2 gene is regulated by hACE2 promoter.Sertoli and Leydig cells from hACE2 transgenic mice can be infected by SARS-CoV-2 pseudovirus in vitro,and severe pathological changes are observed after injecting the SARS-CoV-2 pseudovirus into the seminiferous tubules.Further studies reveal that Sertoli and Leydig cells from hACE2 transgenic mice are also infected by authentic SARS-CoV-2 virus in vitro.After testis interstitium injection,authentic SARS-CoV-2 viruses are first disseminated to the interstitial cells,and then detected inside the seminiferous tubules which in turn cause germ cell loss and disruption of seminiferous tubules.Our study demonstrates that testis is most likely a target of SARS-CoV-2 virus.Attention should be paid to the reproductive function in SARS-CoV-2 patients.

On-chip digitally tunable positive/negative dispersion controller using bidirectional chirped multimode waveguide gratings

A silicon-based digitally tunable positive/negative dispersion controller(DC)is proposed and realized for the first time using the cascaded bidirectional chirped multimode waveguide gratings(CMWGs),achieving positive and negative dispersion by switching the light propagation direction.A 1×2 Mach-Zehnder switch(MZS)and a 2×1 MZS are placed before and after to route the light path for realizing positive/negative switching.The device has Q stages of identical bidirectional CMWGs with a binary sequence.Thus the digital tuning is convenient and scalable,and the total dispersion accumulated by all the stages can be tuned digitally from−(2^(Q)−1)D0 to(2^(Q)−1)D_(0) with a step of D_(0) by controlling the switching states of all 2×2 MZSs,where D_(0) is the dispersion provided by a single bidirectional CMWG unit.Finally,a digitally tunable positive/negative DC with Q=4 is designed and fabricated.These CMWGs are designed with a 4-mm-long grating section,enabling the dispersion D_(0) of about 4.16 ps∕nm in a 20-nm-wide bandwidth.The dispersion is tuned from−61.53 to 63.77 ps∕nm by switching all MZSs appropriately,and the corresponding group delay is varied from−1021 to 1037 ps.

Activation of NLRP3 Inflammasome via Drp1 Overexpression in Kupffer Cells Aggravates Ischemia-reperfusion Injury in Hepatic Steatosis

Background and Aims:Donors with fatty livers are considered to address the shortage of livers for transplantation,but those livers are particularly sensitive to ischemia-reperfusion injury(IRI),and an increased incidence of graft failure is observed.Kupffer cells account for 20–35%of liver nonparenchymal cells,and have been shown to participate in the process of IRI and inflammatory reactions of hepatic steatosis.NOD-like receptor thermal protein domain-associated protein 3(NLRP3)is an intracellular sensor activated by Kupffer cells to promote generation and participates in IRI.Dynamics-associated protein 1(Drp1)is one of the main proteins regulating mitochondrial division and exacerbates IRI by affecting mitochondrial dynamics.The mechanism of interaction of Kupffer cells with Drp1 and NLRP3 to aggravate IRI has not been clarified.Methods:A mouse model of hepatic steatosis was established by feeding the mice with a high-fat diet.In vitro experiments were performed using AML12 normal mouse liver cells and RAW264.7 mononuclear macrophage cells cultured in medium with palmitate and oleic acid.Western blotting and immunohistochemical(IHC)staining were used to detect the expression of NLRPP3 and Drp1 in IRI in the control and high-fat diet groups.The expression of F4/80+cells during IRI in hepatic steatosis was verified by IHC staining,and the role of NLRPP3 and Drp1 in Kupffer-cell mediated IRI was investigated by targeting Drp-1 inhibition.Results:Drp1 and NLRP3 expression was increased during IRI in hepatic steatosis,and the expression of Drp1 and NLRP3 were decreased after the elimination of Kupffer cells.That indicated Kupffer cells were involved in the process of IRI in hepatic steatosis through the action of Drp1 and NLRP3.After Drp1 inhibition,liver function was restored and NLRP3 expression level was reduced.Conclusions:Kupffer cells aggravated IRI in hepatic steatosis via NLRP3 and Drp1.Drp1 inhibitors might be useful as specific therapeutics to alleviate IRI in hepatic steatosis and may have promise in case of liver donor shortage.

Retrieving the grounding lines of the Riiser-Larsen Ice Shelf using Sentinel-1 SAR images

Accurately locating and studying grounding lines is essential for predicting the response of glaciers to climate change.However,it is challenging tofind grounding lines since they are subglacial features.In this study,Sentinel-1 synthetic aperture radar(SAR)data were utilized to derive the grounding lines of the Riiser-Larsen Ice Shelf.A new method with inspiration drawn from multi-temporal baseline InSAR techniques is proposed.It takes advantage of the temporal consistency of the vertical displacement gradients and identifies grounding zones pixel-by-pixel on a stack of double differential interferograms,thereby providing grounding line proxies.As it fully exploits coherent signals in both spatial and temporal domains,the maximum possible number of grounding zone pixels can be obtained.Moreover,due to the introduction of the concept of the temporal consistency,the method can cope with short term grounding linefluctuations to some extent and may mitigate the influences of atmospheric disturbances and residual ice displacements.The resulting grounding lines are compared with the MEaSUREs Antarctic grounding line product.The comparison confirms the effectiveness of the proposed method and corroborates that the Riiser-Larsen Ice Shelf should have not undergone significant changes over the past few decades.

Reconfigurable multichannel amplitude equalizer based on cascaded silicon photonic microrings

A compact on-chip reconfigurable multichannel amplitude equalizer based on cascaded elliptical microrings is proposed and demonstrated experimentally.With the optimized structure of the elliptical microring with adiabatically varied radii/widths,the average excess loss for each channel in the initialized state is measured to be less than 0.5 d B,while the attenuation dynamic range can be over 20 d B.Flexible tunability through the overlapping of the resonance peaks of adjacent wavelength-channels enables even higher attenuation dynamic ranges up to50 d B.Leveraging the thermo-optic effect and fine wavelength-tuning linearity,precise tuning of the resonance peak can be implemented,enabling dynamic power equalization of each wavelength-channel in wavelengthdivision-multiplexing(WDM)systems and optical frequency combs.The proposed architecture exhibits excellent scalability,which can facilitate the development of long-haul optical transport networks and high-capacity neuromorphic computing systems,while improving the overall performance of optical signals in WDM-related systems.

Orthotopic implantable liver decellularized scaffold for acute liver failure

Decellularized scaffolds have an irreplaceable role in the development of tissue engineering.Challenges in this field are concentrated on shaping macro-scale constructs and maintaining blood flow.Here,we establish a whole liver perfused decellularized scaffold cultured with hepatocytes for transplantable bioengineered liver construction.Owing to retained intact gross morphology of liver,geometric structure and biomechanical environment can support whole liver lobe transplantation.Besides,unremoved extracellular matrix(ECM)and vascular net-works can delivery continuous nutrient for cell adhesion.Based on recellularized bioengineering liver scaffold,we have demonstrated its excellent hepatic functions when it orthotopic implanted in acute liver failure(ALF)rats,along with the prolonged survival rate and improved biochemical indicators.These outstanding properties indicate that the orthotopic implantable liver scaffold has broad clinical application prospects in the treatment of ALF and other regeneration diseases.

Enhanced protective immunity against SARS-CoV-2 elicited by a VSV vector expressing a chimeric spike protein

SARS-CoV-2 and SARS-CoV are genetically related coronavirus and share the same cellular receptor ACE2.By replacing the VSV glycoprotein with the spikes(S)of SARS-CoV-2 and SARS-CoV,we generated two replication-competent recombinant viruses,rVSVSARS-CoV-2 and rVSV-SARS-CoV.Using wild-type and human ACE2(hACE2)knock-in mouse models,we found a single dose of rVSV-SARS-CoV could elicit strong humoral immune response via both intranasal(i.n.)and intramuscular(i.m.)routes.Despite the high genetic similarity between SARS-CoV-2 and SARS-CoV,no obvious cross-neutralizing activity was observed in the immunized mice sera.In macaques,neutralizing antibody(NAb)titers induced by one i.n.dose of rVSV-SARS-CoV-2 were eight-fold higher than those by a single i.m.dose.Thus,our data indicates that rVSV-SARS-CoV-2 might be suitable for i.n.administration instead of the traditional i.m.immunization in human.Because rVSV-SARS-CoV elicited significantly stronger NAb responses than rVSV-SARS-CoV2 in a route-independent manner,we generated a chimeric antigen by replacing the receptor binding domain(RBD)of SARS-CoV S with that from the SARS-CoV-2.rVSV expressing the chimera(rVSV-SARS-CoV/2-RBD)induced significantly increased NAbs against SARS-CoV-2 in mice and macaques than rVSV-SARS-CoV-2,with a safe Th1-biased response.Serum immunized with rVSV-SARS-CoV/2-RBD showed no cross-reactivity with SARS-CoV.hACE2 mice receiving a single i.m.dose of either rVSV-SARS-CoV-2 or rVSV-SARSCoV/2-RBD were fully protected against SARS-CoV-2 challenge without obvious lesions in the lungs.Our results suggest that transplantation of SARS-CoV-2 RBD into the S protein of SARS-CoV might be a promising antigen design for COVID-19 vaccines.

A comparison of the biological activities of ethyl acetate fractions from the stems and leaves of Penthorum chinense Pursh

Penthorum chinense Pursh(PCP)is a popular traditional medicinal plant in China,widely used for the treatment of a variety of liver diseases.Although it has been long recognized that the main active elements of PCP are contained in ethyl acetate fraction(EAF),little is known so far in terms of the relative effectiveness of EAF derived from the stems versus leaves of this plant.In the current study,we prepared EAF by reflux extraction and sequential extraction from the stems(SEAF)and leaves(LEAF)of PCP and tested their hepatoprotective efficacies.The extract rates and flavonoid contents of LEAF were higher than those of SEAF.EAFs(>50μg·mL^(–1))prevented lipid accumulation in cells and protected against lipotoxicity injury when the concentration exceeded 25μg·mL^(–1).More than 95%free radicals released by 2,2-diphenyl-1-picrylhydrazyl(DPPH)were eliminated by 25μg·mL^(–1)SEAF and 50μg·mL^(–1)LEAF,respectively.Further,EAFs(25μg·mL^(–1))also showed protective antioxidant effects,with the activity of LEAF being significantly higher than that of SEAF.EAFs(10 mg·mL^(–1))also showed similar unspecific bacteriostatic activity.In comparison with SEAF,LEAF contained more flavonoids and had a higher anti-oxidation capability and for these reasons we suggest it should be better for clinical use.