SPX-domain-containing proteins (SPXs) play an important role in inorganic phosphate (Pi) sensing,signaling,and transport in eukaryotes.In plants,SPXs are known to integrate cellular Pi status and negatively regulate t...SPX-domain-containing proteins (SPXs) play an important role in inorganic phosphate (Pi) sensing,signaling,and transport in eukaryotes.In plants,SPXs are known to integrate cellular Pi status and negatively regulate the activity of Pi central regulators,the PHOSPATE STARVATION RESPONSE proteins (PHRs).The stability of SPXs,such as SPX4,is reduced under Pi-deficient conditions.However,the mechanisms by which SPXs are degraded remain unclear.In this study,using a yeast-twhybrid screen we iden.tified two RING-finger ubiquitin E3 ligases regulating SPX4 degradation,designated SDEL1 and SDEL2,which were post-transcriptionally induced by Pi starvation.We found that both SDELs were located in the nucleus and cytoplasm,had ubiquitin E3 ligase activity,and directly ubiquitinated the K^213 and K^299 lysine residues in SPX4 to regulate its stability.Furthermore,we found that PHR2,a Pi central regulator in rice,could compete with SDELs by interacting with SPX4 under Pi-sufficient conditions,which protected SPX4 from ubiquitination and degradation.Consistent with the biochemical function of SDEL1 and SDEL2,overexpression of SDEL1 or SDEL2 resulted in Pi overaccumulation and induced Pi-starvation signaling even under Pi-sufficient conditions.Conversely,their loss-of-function mutants displayed decreased Pi accumulation and reduced Pi-starvation signaling.Collectively,our study revealed that SDEL1 and SDEL2 facilitate the degradation of SPX4 to modulate PHR2 activity and regulate Pi homeostasis and Pi signaling in response to external Pi availability in rice.展开更多
As the interval following the biggest Phanerozoic mass extinction at the end of Permian, the Early Triassic is characterized by an immature, poorly functioned ecosystem.The effects of these extreme environmental condi...As the interval following the biggest Phanerozoic mass extinction at the end of Permian, the Early Triassic is characterized by an immature, poorly functioned ecosystem.The effects of these extreme environmental conditions can be mirrored by the changes in the δ13C record of marine carbonates.However, the details about the carbon isotopic composition and evolution of the Early Triassic seawater remain poorly understood.A dataset of new δ13C and δ18O values as well as selected major and trace element data (including concentrations of CaO, MgO, Mn, and Sr) was obtained from 113 marine carbonate samples collected in Eastern Sichuan Basin.The isotopic and elemental data are used to evaluate effects of thermochemical sulfate reduction on δ13C.The δ13C values of a few samples affected by thermochemical sulfate reduction were corrected.By combining carbonate δ13C results in our investigated sections, we constructed a composite curve of the Lower Triassic.The results reveal a δ13C anomaly of carbonate rocks throughout the Early Triassic, accompanied by some rapid jumps and falls, such as those from approximately -2‰ to the extremely high value of 8‰ within a period of about 5 Ma.The Early Triassic δ13C profile derived from Eastern Sichuan Basin shows a close correspondence with Guandao section in Guizhou Province, whereas it yields an excursion pattern differing from Chaohu section in Anhui Province of the Lower Yangtze region (with the δ13C value from the minimum around -6‰ to the maximum near 4‰).The higher δ13C values and the positive carbon isotope excursions in the Lower Triassic from Eastern Sichuan Basin were most likely a consequence of the principal environmental change that may include: (1) the barren land surface due to the absence of vegetation, (2) the loss of diverse marine invertebrate groups and marine carbonates, (3) the thriving of bacteria, algae and methanogenus in ocean ecosystems, and (4) the local effect of the repositories of isotopically light carbon occurred in the form of meth展开更多
Clostridium butyricum has been widely considered an antibiotic substitute in recent years.It can promote growth performance,improve the immune response and enhance the intestinal barrier function of the host.In the pr...Clostridium butyricum has been widely considered an antibiotic substitute in recent years.It can promote growth performance,improve the immune response and enhance the intestinal barrier function of the host.In the present study,1-d-old Arbor Acres(AA)broilers were fed C.butyricum(1×109 cfu/kg)for 28 d.The transcriptomic characteristics of epithelial cells of the cecal mucosa were determined by RNA-sequence,and the cecal microbiota composition was explored by 16 S ribosomal RNA gene sequencing.The changes in the intestinal mucosa of broilers were then analyzed by tissue staining.Gene Ontology(GO)annotations identified substance transport and processes and pathways that might participate in intestinal development and cell viability.Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway analysis revealed that the differentially expressed genes are involved in numerous pathways related to amino acid and vitamin metabolism and antioxidant and defensive functions,among others.The relative expression of some genes associated with intestinal barrier function(claudins 2,15,19,and 23,tight junction proteins 1,2,and 3 and mucin 1)was significantly increased in the treatment group(P<0.05 or P<0.01).Moreover,the proportion of Firmicutes was higher in the C.butyricum-treated group,whereas the proportion of Proteobacteria was higher in the control group.At the genus level,the relative abundances of Butyricicoccus and Lactobacillus,among other bacteria,were increased after C.butyricum supplementation.The tissue staining analysis showed that the cecal mucosa of broilers was significantly ameliorated after the addition of C.butyricum(P<0.05 or P<0.01).These results showed that dietary supplementation with C.butyricum can enhance the antioxidant capacity,mucosal barrier function,and stabilize the cecal microbiota,resulting in improving the growth performance.展开更多
Background:Resistance to ferroptosis,a regulated cell death caused by irondependent excessive accumulation of lipid peroxides,has recently been linked to lung adenocarcinoma(LUAD).Intracellular antioxidant systems are...Background:Resistance to ferroptosis,a regulated cell death caused by irondependent excessive accumulation of lipid peroxides,has recently been linked to lung adenocarcinoma(LUAD).Intracellular antioxidant systems are required for protection against ferroptosis.The purpose of the present studywas to investigate whether and how extracellular system desensitizes LUAD cells to ferroptosis.Methods:Established human lung fibroblasts MRC-5,WI38,and human LUAD H1650,PC9,H1975,H358,A549,and H1299 cell lines,tumor and matched normal adjacent tissues of LUAD,and plasma from healthy individuals and LUAD patients were used in this study.Immunohistochemistry and immunoblotting were used to analyze protein expression,and quantitative reverse transcription-PCR was used to analyze mRNA expression.Cell viability,cell death,and the lipid reactive oxygen species generationwere measured to evaluate the responses to ferroptosis.Exosomes were observed using transmission electron microscope.The localization of arachidonic acid(AA)was detected using click chemistry labeling followed by confocal microscopy.Interactions between RNAs and proteins were detected using RNA pull-down,RNA immunoprecipitation and photoactivatable ribonucleoside-enhanced crosslinking and immunoprecipitation methods.Proteomic analysis was used to investigate RNA-regulated proteins,and metabolomic analysis was performed to analyze metabolites.Cellderived xenograft,patient-derived xenograft,cell-implanted intrapulmonary LUAD mouse models and plasma/tissue specimens from LUAD patients were used to validate the molecular mechanism.Results:Plasma exosome from LUAD patients specifically reduced lipid peroxidation and desensitized LUAD cells to ferroptosis.A potential explanation is that exosomal circRNA_101093(cir93)maintained an elevation in intracellular cir93 in LUAD to modulate AA,a poly-unsaturated fatty acid critical for ferroptosisassociated increased peroxidation in the plasma membrane.Mechanistically,cir93 interacted with and increased fatty acid-binding protei展开更多
Insoluble dietary fiber(IDF)and soluble dietary fiber(SDF)extracted from wheat bran were modifi ed by snail enzyme and their physicochemical properties(water retention capacity and oil retention capacity),functional p...Insoluble dietary fiber(IDF)and soluble dietary fiber(SDF)extracted from wheat bran were modifi ed by snail enzyme and their physicochemical properties(water retention capacity and oil retention capacity),functional properties(cholesterol adsorption capacity,glucose adsorption capacity and antioxidant activity)and structural characterizations were evaluated.The results showed that snail enzyme modification led to the significant increase in oil retention capacity of IDF,glucose adsorption capacity and cholesterol adsorption capacity of IDF and SDF.Enzymatic modification also markedly improved the DPPH radical scavenging capacity and reducing power of IDF and SDF.Meanwhile,scanning electron microscopy(SEM)analysis indicated the microstructures of IDF and SDF powders were signifi cantly changed.Fourier transfer-infrared spectrometry(FT-IR)showed that snail enzyme modifi cation could degrade the part of cellulose and hemicellulose of IDF and SDF.All these improved physicochemical and functional properties of IDF and SDF might depend on their structural changes.It suggested that snail enzyme modifi cation could effectively improve physicochemical and functional properties of IDF and SDF from wheat bran.展开更多
The European Space Agency(ESA)’s Swarm constellation of a trio of geomagnetic survey satellites in nearly circular polar orbits at altitude about 500 km was launched on 22 November 2013 and has been mapping the Earth...The European Space Agency(ESA)’s Swarm constellation of a trio of geomagnetic survey satellites in nearly circular polar orbits at altitude about 500 km was launched on 22 November 2013 and has been mapping the Earth’s global magnetic field in unprecedented details,helping scientists better understand how the geomagnetic field is generated and maintained inside the Earth’s fluid core and how the Earth’s external magnetic environment is changing.This review discusses a new novel constellation of the geomagnetic survey satellites that consists of at least four satellites:two satellites are in lower-latitude and nearly circular orbits at altitude about 450 km;two further satellites are marked by nearly polar but strongly eccentric orbits with perigee about 200 km and apogee about 5000 km.The new geomagnetic satellites are equipped with highly stable optical benches,high-precision fluxgate magnetometers and scalar magnetometers which are capable of mapping the Earth’s three-dimensional magnetic field in unprecedented accuracies and details.The new constellation will help elucidate different contributions to the measured geomagnetic field:the core dynamo field,the lithospheric magnetic field,the magnetic fields produced by currents in the ionosphere and the magnetosphere as well as by the currents coupling the ionosphere and magnetosphere,and the magnetic fields induced from the electrically conducting mantle,lithosphere and oceans.In comparison to the Swarm mission,it will provide higher-accuracy,higher-resolution and higher-dimension measurements of the geomagnetic field required for shedding new insights into the core dynamo processes and the Earth’s space magnetic systems along with a wide range of important applications.展开更多
Production of reactive oxygen species(ROS)via the activity of respiratory burst oxidase homologs(RBOHs)plays a vital role in multiple layers of the plant immune system,including pathogen-associated molecular pattern-t...Production of reactive oxygen species(ROS)via the activity of respiratory burst oxidase homologs(RBOHs)plays a vital role in multiple layers of the plant immune system,including pathogen-associated molecular pattern-triggered immunity(PTI),damage-associated molecular pattern-triggered immunity(DTI),effector-triggered immunity(ETI),and systemic acquired resistance(SAR).It is generally established that RBOHD is activated by different receptor-like cytoplasmic kinases(RLCKs)in response to various immune elicitors.In this study,we showed that RPM1-INDUCED PROTEIN KINASE(RIPK),an RLCK VII subfamily member,contributes to ROS production in multiple layers of plant immune system.The ripk mutants showed reduced ROS production in response to treatment with all examined immune elicitors that trigger PTI,DTI,ETI,and SAR.We found that RIPK can directly phosphorylate the N-terminal region of RBOHD in vitro,and the levels of phosphorylated S343/S347 residues of RBOHD are sigfniciantly lower in ripk mutants compared with the wild type upon treatment with all tested immune elicitors.We further demonstrated that phosphorylation of RIPK is required for its function in regulating RBOHD-mediated ROS production.Similar to rbohd,ripk mutants showed reduced stomatal closure and impaired SAR,and were susceptible to the necrotrophic bacterium Pectobacterium carotovorum.Collectively,our results indicate that RIPK regulates broad-spectrum RBOHD-mediated ROS signaling during PTI,DTI,ETI,and SAR,leading to subsequent RBOHD-dependent immune responses.展开更多
Metal halide perovskites are crystalline materials originally developed out of scientific curiosity. They have shown great potential as active materials in optoelectronic applications. In the last 6 years, their certi...Metal halide perovskites are crystalline materials originally developed out of scientific curiosity. They have shown great potential as active materials in optoelectronic applications. In the last 6 years, their certified photovoltaic efficiencies have reached 22.1%. Compared to bulk halide perovskites, low-dimensional ones exhibited novel physical properties. The photoluminescence quantum yields of perovskite quantum dots are close to 100%. The external quantum efficiencies and current efficiencies of perovskite quantum dot light-emitting diodes have reached 8% and 43 cd A^(-1),respectively, and their nanowire lasers show ultralow-threshold room-temperature lasing with emission tunability and ease of synthesis. Perovskite nanowire photodetectors reached a responsivity of 10 A W^(-1)and a specific normalized detectivity of the order of 10^(12 )Jones. Different from most reported reviews focusing on photovoltaic applications, we summarize the rapid progress in the study of low-dimensional perovskite materials, as well as their promising applications in optoelectronic devices. In particular, we review the wide tunability of fabrication methods and the state-of-the-art research outputs of low-dimensional perovskite optoelectronic devices. Finally, the anticipated challenges and potential for this exciting research are proposed.展开更多
Phosphorous(P)and iron(Fe),two essential nutrients for plant growth and development,are highly abundant elements in the earth's crust but often display low availability to plants.Due to the ability to form insolub...Phosphorous(P)and iron(Fe),two essential nutrients for plant growth and development,are highly abundant elements in the earth's crust but often display low availability to plants.Due to the ability to form insoluble complexes,the antagonistic interaction between P and Fe nutrition in plants has been noticed for decades.However,the underlying molecular mechanism modulating the signaling and homeostasis between them re-mains obscure.Here,we show that the possible iron sensors HRZs,the iron deficiency-induced E3 ligases,could interact with the central regulator of phosphate(Pi)signaling,PHR2,and prompt its ubiquitination at lysine residues K319 and K328,leading to its degradation in rice.Consistent with this,the hrzs mutants dis-played a high Pi accumulation phenotype.Furthermore,we found that iron deficiency could attenuate Pi star-vation signaling by inducing the expression of HRZs,which in turn trigger PHR2 protein degradation.Inter-estingly,on the other hand,rice PHRs could negatively regulate the expression of HRZs to modulate iron deficiency responses.Therefore,PHR2 and HRZs form a reciprocal inhibitory module to coordinate Pi and iron signaling and homeostasis in rice.Taken together,our results uncover a molecular link between Pi and iron master regulators,which fine-tunes plant adaptation to Pi and iron availability in rice.展开更多
Carbon burial in lake sediments is an important component of the global carbon cycle. However, little is known about the magnitude of carbon sequestered in lake sediments over the arid/semiarid region of China(ASAC).I...Carbon burial in lake sediments is an important component of the global carbon cycle. However, little is known about the magnitude of carbon sequestered in lake sediments over the arid/semiarid region of China(ASAC).In this study, we estimate both organic and inorganic carbon burial since *AD 1800 based on nine lakes in ASAC,and discuss the most plausible factors controlling carbon burial. Our estimates show that the annual organic carbon burial rate(OCBR) ranges from 5.3 to 129.8 g cm-2year-1(weighted mean of 49.9 g cm-2year-1), leading to a standing stock of 1.1–24.0 kg cm-2(weighted mean of 8.6 kg cm-2)and a regional sum of *108 Tg organic carbon sequestered since *AD 1800. The annual inorganic carbon burial rate(ICBR) ranges from 11.4 to 124.0 g cm-2year-1(weighted mean of 48.3 g cm-2year-1), which is slightly lower than OCBR. The inorganic carbon standing stock ranges from2.4 to 26.0 kg cm-2(weighted mean of 8.1 kg cm-2),resulting in a sum of *101 Tg regional inorganic carbon burial since *AD 1800, which is slightly lower than the organic carbon sequestration. OCBR in ASAC shows a continuously increasing trend since *AD 1950, which is possibly due to the high autochthonous and allochthonous primary production and subsequently high sedimentation rate in the lakes. This increasing carbon burial is possibly related to both climatic changes and enhanced anthropogenic activities, such as land use change, deforestation, and eutrophication in the lake. Furthermore, OCBR and ICBR are expected to continuously increase under the scenario of increasing precipitation and runoff and enhanced anthropogenic activities.The results of this research show that the buried carbon in lake sediments of the ASAC region constitutes a significant and large carbon pool, which should be considered and integrated into the global carbon cycle.展开更多
The revolutionary role of tissue adhesives in wound closure,tissue sealing,and bleeding control necessitates the development of multifunctional materials capable of effective and scarless healing.In contrast to the us...The revolutionary role of tissue adhesives in wound closure,tissue sealing,and bleeding control necessitates the development of multifunctional materials capable of effective and scarless healing.In contrast to the use of traditionally utilized toxic oxidative crosslinking initiators(exemplified by sodium periodate and silver nitrate),herein,the natural polyphenolic compound tannic acid(TA)was used to achieve near instantaneous(<25s),hydrogen bond mediated gelation of citrate-based mussel-inspired bioadhesives combining anti-oxidant,anti-inflammatory,and antimicrobial activities(3A-TCMBAs).The resulting materials were self-healing and possessed low swelling ratios(<60%)as well as considerable mechanical strength(up to~1.0 MPa),elasticity(elongation~2700%),and adhesion(up to 40 kPa).The 3A-TCMBAs showed strong in vitro and in vivo anti-oxidant ability,favorable cytocompatibility and cell migration,as well as photothermal antimicrobial activity against both Staphylococcus aureus and Escherichia coli(>90%bacterial death upon near-infrared(NIR)irradiation).In vivo evaluation in both an infected full-thickness skin wound model and a rat skin incision model demonstrated that 3A-TCMBAs+NIR treatment could promote wound closure and collagen deposition and improve the collagen Ⅰ/Ⅲ ratio on wound sites while simultaneously inhibiting the expression of pro-inflammatory cytokines.Further,phased angiogenesis was observed via promotion in the early wound closure phases followed by inhibition and triggering of degradation&remodeling of the extracellular matrix(ECM)in the late stage(supported by phased CD31(platelet endothelial cell adhesion molecule-1)PDGF(platelet-derived growth factor)and VEGF(vascular endothelial growth factor)expression as well as elevated matrix metalloprotein-9(MMP-9)expression on day 21),resulting in scarless wound healing.The significant convergence of material and bioactive properties elucidated above warrant further exploration of 3A-TCMBAs as a significant,new class of bioadhesive.展开更多
The microstructure of 40Cr and T10A steel sample and its surface to be welded is ultra-fined through salt-bath cyclic quenching and high frequency hardening, then the surface is cleaned. Under non-vacuum and no shield...The microstructure of 40Cr and T10A steel sample and its surface to be welded is ultra-fined through salt-bath cyclic quenching and high frequency hardening, then the surface is cleaned. Under non-vacuum and no shielded gas, the welding parameter of isothermal superplastic solidphase welding and the effect of surface microstructure prior to pressure welding on the quality of joint are studied. At the temperature of 730~750℃ and at initial strain rate of (2~4) × 10-4 s-l, the strength of the joint is up to or close to that of 40Cr base metal in 3-5 min pressure welding展开更多
Hypoxia is beneficial for the differentiation of stem cells transplanted for myocardial injury,but mechanisms underlying this benefit remain unsolved. Here, we report the impact of hypoxia-induced Jagged1 expression i...Hypoxia is beneficial for the differentiation of stem cells transplanted for myocardial injury,but mechanisms underlying this benefit remain unsolved. Here, we report the impact of hypoxia-induced Jagged1 expression in cardiomyocytes(CMs) for driving the differentiation of cardiac stem cells(CSCs).Forced hypoxia-inducible factor 1α(HIF-1α) expression and physical hypoxia(5% O_2) treatment could induce Jagged1 expression in neonatal rat CMs. Pharmacological inhibition of HIF-1α by YC-1 attenuated hypoxia-promoted Jagged1 expression in CMs. An ERK inhibitor(PD98059), but not inhibitors of JNK(SP600125), Notch(DAPT), NF-κB(PTDC), JAK(AG490), or STAT3(Stattic) suppressed hypoxiainduced Jagged1 protein expression in CMs. c-Kit^+ CSCs isolated from neonatal rat hearts using a magnetic-activated cell sorting method expressed GATA4, SM22α or vWF, but not Nkx2.5 and cTnI.Moreover, 87.3% of freshly isolated CSCs displayed Notch1 receptor expression. Direct co-culture of CMs with BrdU-labeled CSCs enhanced CSCs differentiation, as evidenced by an increased number of BrdU^+/Nkx2.5^+ cells, while intermittent hypoxia for 21 days promoted co-culture-triggered differentiation of CSCs into CM-like cells. Notably, YC-1 and DAPT attenuated hypoxia-induced differentiation.Our results suggest that hypoxia induces Jagged1 expression in CMs primarily through ERK signaling,and facilitates early cardiac lineage differentiation of CSCs in CM/CSC co-cultures via HIF-1α/Jagged1/Notch signaling.展开更多
The heavy metal ions,especially Cd^(2+),Pb^(2+) and Hg^(2+),show extremely hazard to the environment and human being.The measurement of heavy metal ions using sensors is catching more and more attention for its advant...The heavy metal ions,especially Cd^(2+),Pb^(2+) and Hg^(2+),show extremely hazard to the environment and human being.The measurement of heavy metal ions using sensors is catching more and more attention for its advantages of high sensitivity and selectivity,low-cost,convenience to handle and rapid detection.In recent years,nanomaterials such as gold nanoparticles(NPs),magnetic nanoparticles,graphene and nanocomposite materials are applied in sensors for improving sensitivity and selectivity,making the research on electrochemical(EC) sensors,spectrometric biosensors and colorimetric biosensors become a hot spot in the application to investigate heavy metal ions,in particular,Cd^(2+),Pb^(2+) and Hg^(2+).In this short review,the research of advanced detection of Cd^(2+),Pb^(2+) and Hg^(2+) and its progress based on nanomaterial sensors in recent years is reviewed.展开更多
Aviation kerosene is commonly used in combustion and regenerative engine cooling processes in propulsion and power-generation systems,including rocket,scramjet,and advanced gas turbine engines.In this paper,many surro...Aviation kerosene is commonly used in combustion and regenerative engine cooling processes in propulsion and power-generation systems,including rocket,scramjet,and advanced gas turbine engines.In this paper,many surrogate models proposed in the open literature are examined for their applicability and accuracy in calculating thermodynamic and transport properties of the China aviation kerosene RP-3 at supercritical pressures,based on the extended corresponding-states methods.The enthalpy change from endothermic decomposition and low heating value from combustion of the jet fuel are also evaluated.Results from a number of simple and representative surrogate models,which contain species components ranging from 1 to10,are analyzed in detail.Data analyses indicate that a surrogate model with four species is the best choice for thermophysical property calculations under the tested conditions,with fluid temperature up to 650 K at various supercritical pressures.The surrogate model is particularly accurate in predicting the pseudo-critical temperature of aviation kerosene RP-3 at a supercritical pressure.A simple surrogate model containing the n-decane species and a surrogate model containing 10 species are the other two acceptable options.The work conducted herein is of practical importance for theoretical analyses and numerical simulations of various physicochemical processes at engine operating conditions.展开更多
A series of ZSM-5 zeolites, with the morphologies of sphere, sphere with cubic particles on the surface, and cubic particles, were synthesized by hydrothermal method using n-butylamine as the template, assisted by the...A series of ZSM-5 zeolites, with the morphologies of sphere, sphere with cubic particles on the surface, and cubic particles, were synthesized by hydrothermal method using n-butylamine as the template, assisted by the addition of NaC1 and crystal seed. X-ray diffraction （XRD）, scanning electron microscope （SEM）, X-ray fluorescence （XRF） and temperature-programmed desorption of ammonia （NH3-TPD） were used to characterize these samples. The samples were tested with toluene methylation reaction. The modified sample composed of spherical particles with 3 μm crystal particles on the surface had a para-xylene selectivity of 95% and maintained 79% of the initial conversion after running the reaction for 50 h. This modified samole showed the best stability amonz the tested three modified samoles.展开更多
Metal-halide perovskites are novel optoelectronic materials that are considered good candidates for solar harvesting and light emitting applications. In this study, we develop a reproducible and low-cost approach for ...Metal-halide perovskites are novel optoelectronic materials that are considered good candidates for solar harvesting and light emitting applications. In this study, we develop a reproducible and low-cost approach for synthesizing high- quality cesium lead halide perovskite （CsPbX3, X = CI, Br, and I or C1/Br and I/Br） nanocrystals （NCs） by direct heating of precursors in octadecene in air. Experimental results show that the particle size and composition of as-prepared CsPbX3 nanocrystals can be successfully tuned by a simple variation of reaction temperature. The emission peak positions of the as-prepared nanocrystals can be conveniently tuned from the UV to the NIR （360-700 nm） region, and the quantum yield of the as-obtained samples （green and red emissions） can reach up to 87%. The structures and chemical compositions of the as-obtained NCs were characterized by transmission electron microscopy, X-ray diffraction, and elemental analysis. This proposed synthetic route can yield large amounts of high-quality NCs with a one-batch reaction, usually on the gram scale, and could pave the way for further applications of perovskite-based light-emitting and photovoltaic solar cells.展开更多
The purpose of this work is to explore the effects of the introduction methods of Ce^4+and Zr^4+on the physicochemical properties,activity,and K tolerance of V2 O5-WO3/TiO2 catalyst for the selective catalytic reducti...The purpose of this work is to explore the effects of the introduction methods of Ce^4+and Zr^4+on the physicochemical properties,activity,and K tolerance of V2 O5-WO3/TiO2 catalyst for the selective catalytic reduction of NOx by NH3.Four different methods,namely pre-impregnation,post-impregnation,coimpregnation,and co-precipitation,were used to synthesize a series of V2 O5-WO3-TiO2-CeO2-ZrO2 catalysts.The catalysts were characterized by XRD,BET,NH3-TPD,XPS,and H2-TPR techniques.Moreover,the activity and anti-K poisoning performance were tested by an NH3-SCR model reaction.The results show that the introduction of Ce^4+and Zr^4+can improve the catalytic performance of V2O5-WO3/TiO2 catalyst,but the impregnation method cannot enhance the anti-K poisoning performance.Ce^4+and Zr^4+introduced by co-precipitation method can effectively improve the tolerance of K,which is mainly due to the incorporation of Ce^4+and Zr^4+into TiO2 lattice to form a uniform TiO2-CeO2-ZrO2 solid solution,resulting in the optimal surface acidity and redox performance,and reducing the decreases caused by Kpoisoning.Furthermore,based on the best introduction method,we further optimized the molar ratio of Ce^4+/Zr^4+,It is found that the catalyst exhibits the best anti-K poisoning performance when the molar ratio of Ce^4+/Zr^4+is 2:1.展开更多
The natural gas from the Triassic Feixianguan Formation of Northeast Sichuan Basin contains high H2S whereas relatively low CO2 concentrations and the CO2 display high δ13C values (ranging from -5.81‰ to 3.3‰ (PDB)...The natural gas from the Triassic Feixianguan Formation of Northeast Sichuan Basin contains high H2S whereas relatively low CO2 concentrations and the CO2 display high δ13C values (ranging from -5.81‰ to 3.3‰ (PDB)). This seems to contradict the conventional wisdom that TSR should be a primary source of CO2 in natural gas from the Feixianguan Formation. In contrast, many authigenic calcite samples from these sites display very low δ13C values (ranging from -18.4‰ to -10.3‰ (PDB)). This suggests that the carbon from TSR source dominated the formation of calcite whereas the carbon from inorganic source came into CO2 in natural gas. In order to assess the origin of CO2 from these H2S-rich sites, we have calculated the relative contributions of organic and inorganic carbon sources to the CO2 and authigenic calcite. The organic carbon source possibly originated from TSR, whereas the inorganic one might be generated from marine carbonates dissolution. This calculation is based on the carbon isotopic compositions of CO2 and authigenic calcite as well as an isotopic mass balance. The results show that the contribution of organic carbon source to the CO2 is only 2%, whereas that to authigenic calcite is as high as 43% on average. Such results combined with thermodynamic evidence indicate that the isotopically light CO2 produced by TSR process may contribute to authigenic calcite precipitation during burial diagenesis. Distinguishable from Ordovician reservoir of Tarim Basin, Feixianguan reservoir of Northeast Sichuan Basin experienced rapid tectonic uplift due to Yanshanian movement after TSR occurred. Such tectonic event could induce temperature decrease and further promote carbonates dissolution. During these processes, secondary porosity has developed in Feixianguan carbonate reservoirs. Therefore, much attention should be paid to the structural highs in search of high quality carbonate reservoirs.展开更多
基金funded by grants from the National Key Research and Development Program of China (2016YFD0100705-1)the National Natural Science Foundation of China (31801925,31772386,and 31601807)+1 种基金Ningbo Department of Science and Technology (2016C11017)KY was supported by the Innovation Program of Chinese Academy of Agricultural Sciences.
文摘SPX-domain-containing proteins (SPXs) play an important role in inorganic phosphate (Pi) sensing,signaling,and transport in eukaryotes.In plants,SPXs are known to integrate cellular Pi status and negatively regulate the activity of Pi central regulators,the PHOSPATE STARVATION RESPONSE proteins (PHRs).The stability of SPXs,such as SPX4,is reduced under Pi-deficient conditions.However,the mechanisms by which SPXs are degraded remain unclear.In this study,using a yeast-twhybrid screen we iden.tified two RING-finger ubiquitin E3 ligases regulating SPX4 degradation,designated SDEL1 and SDEL2,which were post-transcriptionally induced by Pi starvation.We found that both SDELs were located in the nucleus and cytoplasm,had ubiquitin E3 ligase activity,and directly ubiquitinated the K^213 and K^299 lysine residues in SPX4 to regulate its stability.Furthermore,we found that PHR2,a Pi central regulator in rice,could compete with SDELs by interacting with SPX4 under Pi-sufficient conditions,which protected SPX4 from ubiquitination and degradation.Consistent with the biochemical function of SDEL1 and SDEL2,overexpression of SDEL1 or SDEL2 resulted in Pi overaccumulation and induced Pi-starvation signaling even under Pi-sufficient conditions.Conversely,their loss-of-function mutants displayed decreased Pi accumulation and reduced Pi-starvation signaling.Collectively,our study revealed that SDEL1 and SDEL2 facilitate the degradation of SPX4 to modulate PHR2 activity and regulate Pi homeostasis and Pi signaling in response to external Pi availability in rice.
基金supported by National Natural Science Foundation of China(Grant Nos.40839908,41172099)
文摘As the interval following the biggest Phanerozoic mass extinction at the end of Permian, the Early Triassic is characterized by an immature, poorly functioned ecosystem.The effects of these extreme environmental conditions can be mirrored by the changes in the δ13C record of marine carbonates.However, the details about the carbon isotopic composition and evolution of the Early Triassic seawater remain poorly understood.A dataset of new δ13C and δ18O values as well as selected major and trace element data (including concentrations of CaO, MgO, Mn, and Sr) was obtained from 113 marine carbonate samples collected in Eastern Sichuan Basin.The isotopic and elemental data are used to evaluate effects of thermochemical sulfate reduction on δ13C.The δ13C values of a few samples affected by thermochemical sulfate reduction were corrected.By combining carbonate δ13C results in our investigated sections, we constructed a composite curve of the Lower Triassic.The results reveal a δ13C anomaly of carbonate rocks throughout the Early Triassic, accompanied by some rapid jumps and falls, such as those from approximately -2‰ to the extremely high value of 8‰ within a period of about 5 Ma.The Early Triassic δ13C profile derived from Eastern Sichuan Basin shows a close correspondence with Guandao section in Guizhou Province, whereas it yields an excursion pattern differing from Chaohu section in Anhui Province of the Lower Yangtze region (with the δ13C value from the minimum around -6‰ to the maximum near 4‰).The higher δ13C values and the positive carbon isotope excursions in the Lower Triassic from Eastern Sichuan Basin were most likely a consequence of the principal environmental change that may include: (1) the barren land surface due to the absence of vegetation, (2) the loss of diverse marine invertebrate groups and marine carbonates, (3) the thriving of bacteria, algae and methanogenus in ocean ecosystems, and (4) the local effect of the repositories of isotopically light carbon occurred in the form of meth
基金funded by the National Key Research and Development Program of China(No.2018YFD0501904)the Program for Innovation Research Team of Ministry of Education(No.IRT16R23)the Scientific Studio of Zhongyuan Scholars(No.30601985)。
文摘Clostridium butyricum has been widely considered an antibiotic substitute in recent years.It can promote growth performance,improve the immune response and enhance the intestinal barrier function of the host.In the present study,1-d-old Arbor Acres(AA)broilers were fed C.butyricum(1×109 cfu/kg)for 28 d.The transcriptomic characteristics of epithelial cells of the cecal mucosa were determined by RNA-sequence,and the cecal microbiota composition was explored by 16 S ribosomal RNA gene sequencing.The changes in the intestinal mucosa of broilers were then analyzed by tissue staining.Gene Ontology(GO)annotations identified substance transport and processes and pathways that might participate in intestinal development and cell viability.Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway analysis revealed that the differentially expressed genes are involved in numerous pathways related to amino acid and vitamin metabolism and antioxidant and defensive functions,among others.The relative expression of some genes associated with intestinal barrier function(claudins 2,15,19,and 23,tight junction proteins 1,2,and 3 and mucin 1)was significantly increased in the treatment group(P<0.05 or P<0.01).Moreover,the proportion of Firmicutes was higher in the C.butyricum-treated group,whereas the proportion of Proteobacteria was higher in the control group.At the genus level,the relative abundances of Butyricicoccus and Lactobacillus,among other bacteria,were increased after C.butyricum supplementation.The tissue staining analysis showed that the cecal mucosa of broilers was significantly ameliorated after the addition of C.butyricum(P<0.05 or P<0.01).These results showed that dietary supplementation with C.butyricum can enhance the antioxidant capacity,mucosal barrier function,and stabilize the cecal microbiota,resulting in improving the growth performance.
基金National Natural Science Foundation of China,Grant/Award Numbers:81871907,81822029,81872288,82173015,81902315,81902869,81774291ShanghaiMunicipal Education Commission-Gaofeng Clinical Medicine,Grant/Award Number:20191834+5 种基金Project of Clinical Research Supporting SystemClinical Medicine First-class DisciplineShanghai Municipal Education Commission and Shanghai Education Development Foundation,Grant/Award Number:18CG16Shanghai Sailing Program,Grant/Award Number:19YF1444800Science and technology commission of Shanghai municipality project,Grant/Award Numbers:19140902600,21140902800Shanghai ChestHospital,Grant/Award Numbers:2018YNJCM01,2019YNJCM06,2021YNZYJ01,2021YNZYY01,2021YNZYY02。
文摘Background:Resistance to ferroptosis,a regulated cell death caused by irondependent excessive accumulation of lipid peroxides,has recently been linked to lung adenocarcinoma(LUAD).Intracellular antioxidant systems are required for protection against ferroptosis.The purpose of the present studywas to investigate whether and how extracellular system desensitizes LUAD cells to ferroptosis.Methods:Established human lung fibroblasts MRC-5,WI38,and human LUAD H1650,PC9,H1975,H358,A549,and H1299 cell lines,tumor and matched normal adjacent tissues of LUAD,and plasma from healthy individuals and LUAD patients were used in this study.Immunohistochemistry and immunoblotting were used to analyze protein expression,and quantitative reverse transcription-PCR was used to analyze mRNA expression.Cell viability,cell death,and the lipid reactive oxygen species generationwere measured to evaluate the responses to ferroptosis.Exosomes were observed using transmission electron microscope.The localization of arachidonic acid(AA)was detected using click chemistry labeling followed by confocal microscopy.Interactions between RNAs and proteins were detected using RNA pull-down,RNA immunoprecipitation and photoactivatable ribonucleoside-enhanced crosslinking and immunoprecipitation methods.Proteomic analysis was used to investigate RNA-regulated proteins,and metabolomic analysis was performed to analyze metabolites.Cellderived xenograft,patient-derived xenograft,cell-implanted intrapulmonary LUAD mouse models and plasma/tissue specimens from LUAD patients were used to validate the molecular mechanism.Results:Plasma exosome from LUAD patients specifically reduced lipid peroxidation and desensitized LUAD cells to ferroptosis.A potential explanation is that exosomal circRNA_101093(cir93)maintained an elevation in intracellular cir93 in LUAD to modulate AA,a poly-unsaturated fatty acid critical for ferroptosisassociated increased peroxidation in the plasma membrane.Mechanistically,cir93 interacted with and increased fatty acid-binding protei
基金This study was supported by the National Natural Science Foundation of China(81870093)the Research Project of People’s Liberation Army(BXP20C006,BX115C007)the Special Subject Funding of Zhengzhou University and the Natural Science Foundation of Henan Province for Outstanding Youth(202300410365).
文摘Insoluble dietary fiber(IDF)and soluble dietary fiber(SDF)extracted from wheat bran were modifi ed by snail enzyme and their physicochemical properties(water retention capacity and oil retention capacity),functional properties(cholesterol adsorption capacity,glucose adsorption capacity and antioxidant activity)and structural characterizations were evaluated.The results showed that snail enzyme modification led to the significant increase in oil retention capacity of IDF,glucose adsorption capacity and cholesterol adsorption capacity of IDF and SDF.Enzymatic modification also markedly improved the DPPH radical scavenging capacity and reducing power of IDF and SDF.Meanwhile,scanning electron microscopy(SEM)analysis indicated the microstructures of IDF and SDF powders were signifi cantly changed.Fourier transfer-infrared spectrometry(FT-IR)showed that snail enzyme modifi cation could degrade the part of cellulose and hemicellulose of IDF and SDF.All these improved physicochemical and functional properties of IDF and SDF might depend on their structural changes.It suggested that snail enzyme modifi cation could effectively improve physicochemical and functional properties of IDF and SDF from wheat bran.
基金K Zhang is supported by Macao Science and Technology Development Fund grant 0001/2019/A1Macao Foundationthe preresearch Project on Civil Aerospace Technologies of CNSA(Grants No.D020303 and D020308)。
文摘The European Space Agency(ESA)’s Swarm constellation of a trio of geomagnetic survey satellites in nearly circular polar orbits at altitude about 500 km was launched on 22 November 2013 and has been mapping the Earth’s global magnetic field in unprecedented details,helping scientists better understand how the geomagnetic field is generated and maintained inside the Earth’s fluid core and how the Earth’s external magnetic environment is changing.This review discusses a new novel constellation of the geomagnetic survey satellites that consists of at least four satellites:two satellites are in lower-latitude and nearly circular orbits at altitude about 450 km;two further satellites are marked by nearly polar but strongly eccentric orbits with perigee about 200 km and apogee about 5000 km.The new geomagnetic satellites are equipped with highly stable optical benches,high-precision fluxgate magnetometers and scalar magnetometers which are capable of mapping the Earth’s three-dimensional magnetic field in unprecedented accuracies and details.The new constellation will help elucidate different contributions to the measured geomagnetic field:the core dynamo field,the lithospheric magnetic field,the magnetic fields produced by currents in the ionosphere and the magnetosphere as well as by the currents coupling the ionosphere and magnetosphere,and the magnetic fields induced from the electrically conducting mantle,lithosphere and oceans.In comparison to the Swarm mission,it will provide higher-accuracy,higher-resolution and higher-dimension measurements of the geomagnetic field required for shedding new insights into the core dynamo processes and the Earth’s space magnetic systems along with a wide range of important applications.
基金Financial support for this study was provided by the National Key Research and Development Program of China(2018YFD1000800)National Natural Science Foundation of China(31970279 and 31801015)China Postdoctoral Science Foundation(2019T120522 and 2019M652101).
文摘Production of reactive oxygen species(ROS)via the activity of respiratory burst oxidase homologs(RBOHs)plays a vital role in multiple layers of the plant immune system,including pathogen-associated molecular pattern-triggered immunity(PTI),damage-associated molecular pattern-triggered immunity(DTI),effector-triggered immunity(ETI),and systemic acquired resistance(SAR).It is generally established that RBOHD is activated by different receptor-like cytoplasmic kinases(RLCKs)in response to various immune elicitors.In this study,we showed that RPM1-INDUCED PROTEIN KINASE(RIPK),an RLCK VII subfamily member,contributes to ROS production in multiple layers of plant immune system.The ripk mutants showed reduced ROS production in response to treatment with all examined immune elicitors that trigger PTI,DTI,ETI,and SAR.We found that RIPK can directly phosphorylate the N-terminal region of RBOHD in vitro,and the levels of phosphorylated S343/S347 residues of RBOHD are sigfniciantly lower in ripk mutants compared with the wild type upon treatment with all tested immune elicitors.We further demonstrated that phosphorylation of RIPK is required for its function in regulating RBOHD-mediated ROS production.Similar to rbohd,ripk mutants showed reduced stomatal closure and impaired SAR,and were susceptible to the necrotrophic bacterium Pectobacterium carotovorum.Collectively,our results indicate that RIPK regulates broad-spectrum RBOHD-mediated ROS signaling during PTI,DTI,ETI,and SAR,leading to subsequent RBOHD-dependent immune responses.
基金supported by the Doctoral Program of Higher Education(20130142120075)the Fundamental Research Funds for the Central Universities(HUST:2016YXMS032)National Key Research and Development Program of China(Grant No.2016YFB0700702)
文摘Metal halide perovskites are crystalline materials originally developed out of scientific curiosity. They have shown great potential as active materials in optoelectronic applications. In the last 6 years, their certified photovoltaic efficiencies have reached 22.1%. Compared to bulk halide perovskites, low-dimensional ones exhibited novel physical properties. The photoluminescence quantum yields of perovskite quantum dots are close to 100%. The external quantum efficiencies and current efficiencies of perovskite quantum dot light-emitting diodes have reached 8% and 43 cd A^(-1),respectively, and their nanowire lasers show ultralow-threshold room-temperature lasing with emission tunability and ease of synthesis. Perovskite nanowire photodetectors reached a responsivity of 10 A W^(-1)and a specific normalized detectivity of the order of 10^(12 )Jones. Different from most reported reviews focusing on photovoltaic applications, we summarize the rapid progress in the study of low-dimensional perovskite materials, as well as their promising applications in optoelectronic devices. In particular, we review the wide tunability of fabrication methods and the state-of-the-art research outputs of low-dimensional perovskite optoelectronic devices. Finally, the anticipated challenges and potential for this exciting research are proposed.
基金the National Natural Science Foundation of China(31972492,31801925,31972493,and 31772386)Fundamental Research Funds for Central Non-profit Scientific Institution(1610132020001)K.Y.was supported by the Innovation Program of the Chinese Academy of Agricultural Sciences.
文摘Phosphorous(P)and iron(Fe),two essential nutrients for plant growth and development,are highly abundant elements in the earth's crust but often display low availability to plants.Due to the ability to form insoluble complexes,the antagonistic interaction between P and Fe nutrition in plants has been noticed for decades.However,the underlying molecular mechanism modulating the signaling and homeostasis between them re-mains obscure.Here,we show that the possible iron sensors HRZs,the iron deficiency-induced E3 ligases,could interact with the central regulator of phosphate(Pi)signaling,PHR2,and prompt its ubiquitination at lysine residues K319 and K328,leading to its degradation in rice.Consistent with this,the hrzs mutants dis-played a high Pi accumulation phenotype.Furthermore,we found that iron deficiency could attenuate Pi star-vation signaling by inducing the expression of HRZs,which in turn trigger PHR2 protein degradation.Inter-estingly,on the other hand,rice PHRs could negatively regulate the expression of HRZs to modulate iron deficiency responses.Therefore,PHR2 and HRZs form a reciprocal inhibitory module to coordinate Pi and iron signaling and homeostasis in rice.Taken together,our results uncover a molecular link between Pi and iron master regulators,which fine-tunes plant adaptation to Pi and iron availability in rice.
基金funded by the Chinese Academy of Science (CAS) Strategic Priority Research Program (Grant No. XDA05120404)the National Basic Research Program of China (No. 2013CB955903)+1 种基金the State Key Laboratory of Loess and Quaternary Geology (No. SKLLQG1406)the Western Light Talent Culture Project of CAS
文摘Carbon burial in lake sediments is an important component of the global carbon cycle. However, little is known about the magnitude of carbon sequestered in lake sediments over the arid/semiarid region of China(ASAC).In this study, we estimate both organic and inorganic carbon burial since *AD 1800 based on nine lakes in ASAC,and discuss the most plausible factors controlling carbon burial. Our estimates show that the annual organic carbon burial rate(OCBR) ranges from 5.3 to 129.8 g cm-2year-1(weighted mean of 49.9 g cm-2year-1), leading to a standing stock of 1.1–24.0 kg cm-2(weighted mean of 8.6 kg cm-2)and a regional sum of *108 Tg organic carbon sequestered since *AD 1800. The annual inorganic carbon burial rate(ICBR) ranges from 11.4 to 124.0 g cm-2year-1(weighted mean of 48.3 g cm-2year-1), which is slightly lower than OCBR. The inorganic carbon standing stock ranges from2.4 to 26.0 kg cm-2(weighted mean of 8.1 kg cm-2),resulting in a sum of *101 Tg regional inorganic carbon burial since *AD 1800, which is slightly lower than the organic carbon sequestration. OCBR in ASAC shows a continuously increasing trend since *AD 1950, which is possibly due to the high autochthonous and allochthonous primary production and subsequently high sedimentation rate in the lakes. This increasing carbon burial is possibly related to both climatic changes and enhanced anthropogenic activities, such as land use change, deforestation, and eutrophication in the lake. Furthermore, OCBR and ICBR are expected to continuously increase under the scenario of increasing precipitation and runoff and enhanced anthropogenic activities.The results of this research show that the buried carbon in lake sediments of the ASAC region constitutes a significant and large carbon pool, which should be considered and integrated into the global carbon cycle.
基金funded by the National Natural Science Foundation of China(NSFC,Grant No.U21A2099,82102545)the Chinese Postdoctoral Science Foundation(Grant No.2021M701627)the Guangdong Basic and Applied Basic Research Foundation(Grant No.2022A1515011982,2020A1515110062).
文摘The revolutionary role of tissue adhesives in wound closure,tissue sealing,and bleeding control necessitates the development of multifunctional materials capable of effective and scarless healing.In contrast to the use of traditionally utilized toxic oxidative crosslinking initiators(exemplified by sodium periodate and silver nitrate),herein,the natural polyphenolic compound tannic acid(TA)was used to achieve near instantaneous(<25s),hydrogen bond mediated gelation of citrate-based mussel-inspired bioadhesives combining anti-oxidant,anti-inflammatory,and antimicrobial activities(3A-TCMBAs).The resulting materials were self-healing and possessed low swelling ratios(<60%)as well as considerable mechanical strength(up to~1.0 MPa),elasticity(elongation~2700%),and adhesion(up to 40 kPa).The 3A-TCMBAs showed strong in vitro and in vivo anti-oxidant ability,favorable cytocompatibility and cell migration,as well as photothermal antimicrobial activity against both Staphylococcus aureus and Escherichia coli(>90%bacterial death upon near-infrared(NIR)irradiation).In vivo evaluation in both an infected full-thickness skin wound model and a rat skin incision model demonstrated that 3A-TCMBAs+NIR treatment could promote wound closure and collagen deposition and improve the collagen Ⅰ/Ⅲ ratio on wound sites while simultaneously inhibiting the expression of pro-inflammatory cytokines.Further,phased angiogenesis was observed via promotion in the early wound closure phases followed by inhibition and triggering of degradation&remodeling of the extracellular matrix(ECM)in the late stage(supported by phased CD31(platelet endothelial cell adhesion molecule-1)PDGF(platelet-derived growth factor)and VEGF(vascular endothelial growth factor)expression as well as elevated matrix metalloprotein-9(MMP-9)expression on day 21),resulting in scarless wound healing.The significant convergence of material and bioactive properties elucidated above warrant further exploration of 3A-TCMBAs as a significant,new class of bioadhesive.
基金supported by the Henan Natural Science Foundation of China under Grant No.984040900.
文摘The microstructure of 40Cr and T10A steel sample and its surface to be welded is ultra-fined through salt-bath cyclic quenching and high frequency hardening, then the surface is cleaned. Under non-vacuum and no shielded gas, the welding parameter of isothermal superplastic solidphase welding and the effect of surface microstructure prior to pressure welding on the quality of joint are studied. At the temperature of 730~750℃ and at initial strain rate of (2~4) × 10-4 s-l, the strength of the joint is up to or close to that of 40Cr base metal in 3-5 min pressure welding
基金supported by grants from the National Natural Science Foundation of China (Grant Nos.81170121,81460042,81541004 and 81670254)Science and Technology Project of Guangdong Province (2016A020214016)+1 种基金YangFan Plan of Guangdong Province (4YF16007G)Excellent Graduate Student Training Program of Guangdong Medical University (YS2014013)
文摘Hypoxia is beneficial for the differentiation of stem cells transplanted for myocardial injury,but mechanisms underlying this benefit remain unsolved. Here, we report the impact of hypoxia-induced Jagged1 expression in cardiomyocytes(CMs) for driving the differentiation of cardiac stem cells(CSCs).Forced hypoxia-inducible factor 1α(HIF-1α) expression and physical hypoxia(5% O_2) treatment could induce Jagged1 expression in neonatal rat CMs. Pharmacological inhibition of HIF-1α by YC-1 attenuated hypoxia-promoted Jagged1 expression in CMs. An ERK inhibitor(PD98059), but not inhibitors of JNK(SP600125), Notch(DAPT), NF-κB(PTDC), JAK(AG490), or STAT3(Stattic) suppressed hypoxiainduced Jagged1 protein expression in CMs. c-Kit^+ CSCs isolated from neonatal rat hearts using a magnetic-activated cell sorting method expressed GATA4, SM22α or vWF, but not Nkx2.5 and cTnI.Moreover, 87.3% of freshly isolated CSCs displayed Notch1 receptor expression. Direct co-culture of CMs with BrdU-labeled CSCs enhanced CSCs differentiation, as evidenced by an increased number of BrdU^+/Nkx2.5^+ cells, while intermittent hypoxia for 21 days promoted co-culture-triggered differentiation of CSCs into CM-like cells. Notably, YC-1 and DAPT attenuated hypoxia-induced differentiation.Our results suggest that hypoxia induces Jagged1 expression in CMs primarily through ERK signaling,and facilitates early cardiac lineage differentiation of CSCs in CM/CSC co-cultures via HIF-1α/Jagged1/Notch signaling.
基金supported by the National Natural Science Foundation of China(61471168,61571187)China Post-Doctoral Science Foundation(2016T90403)the Economical Forest Cultivation and Utilization of 2011 Collaborative Innovation Center in Hunan Province [(2013) 448]
文摘The heavy metal ions,especially Cd^(2+),Pb^(2+) and Hg^(2+),show extremely hazard to the environment and human being.The measurement of heavy metal ions using sensors is catching more and more attention for its advantages of high sensitivity and selectivity,low-cost,convenience to handle and rapid detection.In recent years,nanomaterials such as gold nanoparticles(NPs),magnetic nanoparticles,graphene and nanocomposite materials are applied in sensors for improving sensitivity and selectivity,making the research on electrochemical(EC) sensors,spectrometric biosensors and colorimetric biosensors become a hot spot in the application to investigate heavy metal ions,in particular,Cd^(2+),Pb^(2+) and Hg^(2+).In this short review,the research of advanced detection of Cd^(2+),Pb^(2+) and Hg^(2+) and its progress based on nanomaterial sensors in recent years is reviewed.
基金supported by the National Natural Science Foundation of China(Grant No.11372277)
文摘Aviation kerosene is commonly used in combustion and regenerative engine cooling processes in propulsion and power-generation systems,including rocket,scramjet,and advanced gas turbine engines.In this paper,many surrogate models proposed in the open literature are examined for their applicability and accuracy in calculating thermodynamic and transport properties of the China aviation kerosene RP-3 at supercritical pressures,based on the extended corresponding-states methods.The enthalpy change from endothermic decomposition and low heating value from combustion of the jet fuel are also evaluated.Results from a number of simple and representative surrogate models,which contain species components ranging from 1 to10,are analyzed in detail.Data analyses indicate that a surrogate model with four species is the best choice for thermophysical property calculations under the tested conditions,with fluid temperature up to 650 K at various supercritical pressures.The surrogate model is particularly accurate in predicting the pseudo-critical temperature of aviation kerosene RP-3 at a supercritical pressure.A simple surrogate model containing the n-decane species and a surrogate model containing 10 species are the other two acceptable options.The work conducted herein is of practical importance for theoretical analyses and numerical simulations of various physicochemical processes at engine operating conditions.
文摘A series of ZSM-5 zeolites, with the morphologies of sphere, sphere with cubic particles on the surface, and cubic particles, were synthesized by hydrothermal method using n-butylamine as the template, assisted by the addition of NaC1 and crystal seed. X-ray diffraction （XRD）, scanning electron microscope （SEM）, X-ray fluorescence （XRF） and temperature-programmed desorption of ammonia （NH3-TPD） were used to characterize these samples. The samples were tested with toluene methylation reaction. The modified sample composed of spherical particles with 3 μm crystal particles on the surface had a para-xylene selectivity of 95% and maintained 79% of the initial conversion after running the reaction for 50 h. This modified samole showed the best stability amonz the tested three modified samoles.
基金This work was supported by the National Natural Science Foundation of China （Nos. 21373097 and 51072067）.
文摘Metal-halide perovskites are novel optoelectronic materials that are considered good candidates for solar harvesting and light emitting applications. In this study, we develop a reproducible and low-cost approach for synthesizing high- quality cesium lead halide perovskite （CsPbX3, X = CI, Br, and I or C1/Br and I/Br） nanocrystals （NCs） by direct heating of precursors in octadecene in air. Experimental results show that the particle size and composition of as-prepared CsPbX3 nanocrystals can be successfully tuned by a simple variation of reaction temperature. The emission peak positions of the as-prepared nanocrystals can be conveniently tuned from the UV to the NIR （360-700 nm） region, and the quantum yield of the as-obtained samples （green and red emissions） can reach up to 87%. The structures and chemical compositions of the as-obtained NCs were characterized by transmission electron microscopy, X-ray diffraction, and elemental analysis. This proposed synthetic route can yield large amounts of high-quality NCs with a one-batch reaction, usually on the gram scale, and could pave the way for further applications of perovskite-based light-emitting and photovoltaic solar cells.
基金Project supported by the National Natural Science Foundation of China(21876168)the Key Projects for Common Key Technology Innovation in Key Industries in Chongqing(cstc2016zdcy-ztzx0020-01)+1 种基金Youth Innovation Promotion Association CAS(2019376)the Graduate Innovation Project of Chongqing Technology and Business University(yjscxx201803-028-22)。
文摘The purpose of this work is to explore the effects of the introduction methods of Ce^4+and Zr^4+on the physicochemical properties,activity,and K tolerance of V2 O5-WO3/TiO2 catalyst for the selective catalytic reduction of NOx by NH3.Four different methods,namely pre-impregnation,post-impregnation,coimpregnation,and co-precipitation,were used to synthesize a series of V2 O5-WO3-TiO2-CeO2-ZrO2 catalysts.The catalysts were characterized by XRD,BET,NH3-TPD,XPS,and H2-TPR techniques.Moreover,the activity and anti-K poisoning performance were tested by an NH3-SCR model reaction.The results show that the introduction of Ce^4+and Zr^4+can improve the catalytic performance of V2O5-WO3/TiO2 catalyst,but the impregnation method cannot enhance the anti-K poisoning performance.Ce^4+and Zr^4+introduced by co-precipitation method can effectively improve the tolerance of K,which is mainly due to the incorporation of Ce^4+and Zr^4+into TiO2 lattice to form a uniform TiO2-CeO2-ZrO2 solid solution,resulting in the optimal surface acidity and redox performance,and reducing the decreases caused by Kpoisoning.Furthermore,based on the best introduction method,we further optimized the molar ratio of Ce^4+/Zr^4+,It is found that the catalyst exhibits the best anti-K poisoning performance when the molar ratio of Ce^4+/Zr^4+is 2:1.
基金supported by National Natural Science Foundation of China (Grant Nos. 40839908, 40672072)
文摘The natural gas from the Triassic Feixianguan Formation of Northeast Sichuan Basin contains high H2S whereas relatively low CO2 concentrations and the CO2 display high δ13C values (ranging from -5.81‰ to 3.3‰ (PDB)). This seems to contradict the conventional wisdom that TSR should be a primary source of CO2 in natural gas from the Feixianguan Formation. In contrast, many authigenic calcite samples from these sites display very low δ13C values (ranging from -18.4‰ to -10.3‰ (PDB)). This suggests that the carbon from TSR source dominated the formation of calcite whereas the carbon from inorganic source came into CO2 in natural gas. In order to assess the origin of CO2 from these H2S-rich sites, we have calculated the relative contributions of organic and inorganic carbon sources to the CO2 and authigenic calcite. The organic carbon source possibly originated from TSR, whereas the inorganic one might be generated from marine carbonates dissolution. This calculation is based on the carbon isotopic compositions of CO2 and authigenic calcite as well as an isotopic mass balance. The results show that the contribution of organic carbon source to the CO2 is only 2%, whereas that to authigenic calcite is as high as 43% on average. Such results combined with thermodynamic evidence indicate that the isotopically light CO2 produced by TSR process may contribute to authigenic calcite precipitation during burial diagenesis. Distinguishable from Ordovician reservoir of Tarim Basin, Feixianguan reservoir of Northeast Sichuan Basin experienced rapid tectonic uplift due to Yanshanian movement after TSR occurred. Such tectonic event could induce temperature decrease and further promote carbonates dissolution. During these processes, secondary porosity has developed in Feixianguan carbonate reservoirs. Therefore, much attention should be paid to the structural highs in search of high quality carbonate reservoirs.
