Zeolite nanosheets with a short b-axis thickness are highly desirable in lots of catalytic reactions due to their reduced diffusion resistance. Nevertheless, conventional synthesis methods usually require expensive st...Zeolite nanosheets with a short b-axis thickness are highly desirable in lots of catalytic reactions due to their reduced diffusion resistance. Nevertheless, conventional synthesis methods usually require expensive structure-directing agents(SDAs), pricey raw materials, and eco-unfriendly fluorine-containing additives. Here, we contributed a cost-effective and fluoride-free synthesis method for synthesizing high-quality MFI zeolite nanosheets through a Silicalite-1(Sil-1) seed suspension and urea cooperative strategy, only with inexpensive colloidal silica as the Si source. Our approach was effective for synthesizing both Sil-1 and aluminum-containing ZSM-5 nanosheets. By optimizing key synthesis parameters,including seed aging time, seed quantity, and urea concentration, we achieved precise control over the crystal face aspect ratio and b-axis thickness. We also revealed a non-classical oriented nanosheet growth mechanism, where Sil-1 seeds induced the formation of quasi-ordered precursor particles, and the(010)crystal planes of these particles facilitated urea adsorption, thereby promoting c-axis-oriented growth.The obtained ZSM-5 nanosheets exhibited exceptional catalytic performance in the benzene alkylation with ethanol, maintaining stability for over 500 h, which is 5 times longer than traditional ZSM-5 catalysts. Furthermore, large-scale production of ZSM-5 nanosheets was successfully carried out in a 3 L highpressure autoclave, yielding samples consistent with those from laboratory-scale synthesis. This work marks a significant step forward in the sustainable and efficient production of MFI nanosheets using inexpensive and environmentally friendly raw materials, offering the broad applicability in catalysis.展开更多
The soil-resident pathogen, Plasmodiophora brassicae, infects cruciferous crops, causing obligate parasitic clubroot disease and posing a significant threat to the Brassica vegetable industry in China. To learn more a...The soil-resident pathogen, Plasmodiophora brassicae, infects cruciferous crops, causing obligate parasitic clubroot disease and posing a significant threat to the Brassica vegetable industry in China. To learn more about its pathogenesis, we reported a Nanopore sequencing-derived25.3 Mb high-quality genome sequence of P. brassicae pathotype 4 strain(P.b 4). Comparing the P.b 4 genome with that of the published P.brassicae e3 genome(P.b e3) identified single nucleotide polymorphisms, structural variations, and small insertions and deletions. We then carried out RNA-sequencing of root samples from a clubroot-susceptible line at 5, 14, and 28 days after inoculation(DAI), and classified genes into five categories based on their expression patterns. Interestingly, 158 genes were highly expressed at 14 DAI, which were enriched in budding cell isotropic bud growth, ascospore wall assembly, spore wall assembly, spore wall biogenesis, and ascospore wall biogenesis.Subsequently, we bioinformatically predicted 555 secreted effector candidates, among which only 125 were expressed during infection and had amino acid lengths less than 400. The putative effector Pb010018, which was highly expressed at 14 DAI, was validated to have a signal peptide using a yeast secretion system. Luciferase activity and co-immunoprecipitation assays demonstrated that Pb010018 interacts with serine hydroxymethyltransferase BrSHMT1, and expression analysis showed that SHMT1 was upregulated in both Arabidopsis and B. rapa during infection. Furthermore, after infection, the Arabidopsis shmt1 mutant(atshmt1) showed reduced severity of clubroot disease, together with downregulated expression of Pb010018. Our results offer new insights into plant-pathogen interaction mechanisms, and provide the possibility for improving Brassica resistance to clubroot disease.展开更多
The identification of fully spin-polarized topological phases in magnetic inorganic materials has attracted significant attention.In this study,through first-principles calculations,we characterize CrCl_(2)(pyz)_(2),a...The identification of fully spin-polarized topological phases in magnetic inorganic materials has attracted significant attention.In this study,through first-principles calculations,we characterize CrCl_(2)(pyz)_(2),a metal-organic framework(MOF),as a nodal chain semimetal.Our results reveal a ferromagnetic ground state in this material,presenting as a half-metal with a single spin channel near the Fermi level.Specifically,the spin-down states form a nodal chain close to the Fermi level,consisting of three nodal loops protected by glide mirror symmetry on distinct planes.Furthermore,fully spin-polarized drumhead surface states corresponding to these nodal loops are identified on the material’s surfaces.Remarkably,we observe the persistence of the fully spin-polarized nodal chain even when tuning the ligand rotation an-gle of the MOF.Furthermore,our investigation delves into the influence of spin-orbit coupling(SOC)on the system,revealing that it has minimal impact on the nodal chain.The robustness of the nodal chain in the presence of SOC underscores its intriguing and resilient nature,indicating its potential utility in various electronic applications.Ultimately,the robust realization of a fully spin-polarized nodal chain in this magnetic MOF system holds promise for applications in the realm of spintronics.展开更多
The utilization of self-assembled monolayers(SAMs)has significantly elevated the power conversion efficiency(PCE)of inverted perovskite solar cells(PSCs).However,the inherent hydrophobicity of these SAMs poses challen...The utilization of self-assembled monolayers(SAMs)has significantly elevated the power conversion efficiency(PCE)of inverted perovskite solar cells(PSCs).However,the inherent hydrophobicity of these SAMs poses challenges in the subsequent printing of perovskite films in PSC upscaling.In this work,we incorporated a multifunctional additive,dimethyl suberimidate dihydrochloride(DMSCl_(2)),into the perovskite precursor to enhance the quality of the blade-coated perovskite film on the SAM interlayer.Characterizations revealed that the function groups of the imino(N-H)and methoxy(CH_(3)O-)DMSCl_(2) facilitate both bonding between perovskite precursor and SAM molecule(Me-4PACz),which facilitates the large-area printing of perovskite film.These interactions also provide effective passivation within the perovskite films and interface defects of PSCs.As a result,a significantly enhanced PCE from 16.62% to 20.37% was obtained for the printed perovskite solar module(93.10 cm^(2))and 25.27% for the small device(0.09 cm^(2)).Remarkable stability was achieved with 93.3% of their initial PCE after 1000 h of continuous maximum power point(MPP)tracking.This report suggests that multifunctional additive doping provides a convenient route for the upscaling of perovskite solar cells with SAM interlayers.展开更多
A glassy(G)phase was formed for Zr-rich Zr70-75(Al,Ni,Cu,Ag)25-30(atomic percent,at.%)melt-spun alloy ribbons.These glassy alloys exhibit the glass transition,followed by a supercooled liquid region and then three-sta...A glassy(G)phase was formed for Zr-rich Zr70-75(Al,Ni,Cu,Ag)25-30(atomic percent,at.%)melt-spun alloy ribbons.These glassy alloys exhibit the glass transition,followed by a supercooled liquid region and then three-stage crystallization.The glass transition temperature and the onset temperature for the first-stage crystallization(Tx1)decrease from 630 to 668 K,respectively for the 70Zr alloy to 619 and 652 K,respectively for the 75Zr alloy.The first-stage exothermic peak is due to the precipitation of an icosahedral quasicrystal(IQ)phase.The IQ particle size decreases from 10 nm to 6 nm with increasing Zr content from 70 at.%to 74 at.%.The[G+IQ]phases change to Zr2 Ni+Zr2(Cu,Ag)phases after the second exothermic peak and then Zr2 Ni+Zr2(Cu,Ag)+Zr5 Al3 phases after the third stage.It is noticed that the as-spun glassy alloy ribbons as well as the annealed[G+IQ]phase ribbons exhibit good bending plasticity.Furthermore,the 70Zr thicker ribbons also exhibit high tensile fracture strength of 1090-1187 MPa and plastic elongation of 0.17%-0.42%.The fracture mode is similar to that of ordinary bulk metallic glasses.The Vickers hardness(H v)is 480 for 70Zr alloy and decreases to 436 for 75Zr alloy.The precipitation of IQ phase causes a significant increase in H v to about 554.The formations of glassy alloys with high Zr contents of 70 at.%-75 at.%by melt spinning as well as the[G+IQ]phase alloys with good bending plasticity by annealing hold promise for the creation of a new type of engineering material,transcending mere academic novelty.展开更多
The doping evolution of the nodal electron dynamics in the trilayer cuprate superconductor Bi_(2)Sr_(2)Ca_(2)Cu_(3)O_(10+δ)(Bi2223)is investigated using high-resolution laser-based angle-resolved photoemission spectr...The doping evolution of the nodal electron dynamics in the trilayer cuprate superconductor Bi_(2)Sr_(2)Ca_(2)Cu_(3)O_(10+δ)(Bi2223)is investigated using high-resolution laser-based angle-resolved photoemission spectroscopy(ARPES).Bi2223single crystals with different doping levels are prepared by controlled annealing,which cover the underdoped,optimallydoped and overdoped regions.The electronic phase diagram of Bi2223 is established which describes the Tcdependence on the sample doping level.The doping dependence of the nodal Fermi momentum for the outer(OP)and inner(IP)CuO_(2)planes is determined.Charge distribution imbalance between the OP and IP CuO_(2)planes is quantified,showing enhanced disparity with increasing doping.Nodal band dispersions demonstrate a prominent kink at~94 meV in the IP band,attributed to the unique Cu coordination in the IP plane,while a weaker~60 meV kink is observed in the OP band.The nodal Fermi velocity of both OP and IP bands is nearly constant at~1.62 eV·A independent of doping.These results provide important information to understand the origin of high Tcand superconductivity mechanism in high temperature cuprate superconductors.展开更多
Background: Trans-province transfer of the patients has been successfully carried out and has greatly relieved the burden of the hospitals in Sichuan Province after Sichuan earthquake. The aim of the study was to retr...Background: Trans-province transfer of the patients has been successfully carried out and has greatly relieved the burden of the hospitals in Sichuan Province after Sichuan earthquake. The aim of the study was to retrospectively analyze the efficacy and feasibility of the trans-province transfer of the multiple trauma patients after Sichuan earthquake. Methods: A retrospective and descriptive analysis was conducted based on the medical records of the multiple trauma patients (ISS ≥ 16) transferred to the Grade 3A hospitals outside Sichuan province. The patients were divided into two groups based on the distance to Sichuan province, i.e., Group A (the seismic patients transferred to Chongqing) and Group B (the seismic patients transferred to the other provinces/ municipalities). A comparison was done in aspects of distance of transfer, time from injury to transfer, vital signs, the infection rates (at transfer and on discharge), injury severity and prognostic indices (cure rate, disability rate and mortality). Results: The distance between Chengdu and the other places was at a wide range of 313 - 1653 km, whereas the time from injury to transfer showed no statistical difference between groups (P > 0.05). There were no significant differences between both groups with respects to patient demographics, injury mechanism, time from injury to transfer, vital signs, infection rate and injury severity. The prognostic indices showed no significant difference, except for FIM scores (P < 0.05). Conclusions: The results of the study indicate that the different distance of the transfer of the multiple trauma patients does not aggravate the severity or deteriorate the prognosis, which proves that the medical supportive transfer system is acceptable, effective and worthy of further implementation in China, which may be ascribed to the advanced transportation system and high level of therapeutic capacity of the hospitals. In the meantime, attention should be paid to psychological intervention and functional rehabilitation during the treatment of the transferred seismic patients.展开更多
Platinum(Pt)supported on Zinc(Zn)modified silicalite-1(S-1)zeolite(denoted as Pt-Zn/S-1)was prepared by using a wetness-impregnation method and applied in the n-hexane aromatization reaction for the first time.Both Le...Platinum(Pt)supported on Zinc(Zn)modified silicalite-1(S-1)zeolite(denoted as Pt-Zn/S-1)was prepared by using a wetness-impregnation method and applied in the n-hexane aromatization reaction for the first time.Both Lewis and Bronsted acid sites were detected in Pt-Zn/S-1 catalyst by means of FT-IR adsorption of NH3 experiment,which were identified as mostly weak and medium ones.Besides,Pt and Zn species showed strong interaction,as revealed by the TPR(Temperature-programmed reduction)and XPS(X-ray photoelectron spectroscopy)experiments.Pt-Zn/S-1 catalyst exhibited excellent aromatization function rather than isomerization and cracking side reactions in the conversion of n-hexane.Pulse experimental study showed that 75.6%of n-hexane conversion and 76.8%of benzene selectivity were obtained over Pt0.1-Zn60/S-l catalyst at 550℃ and under atmospheric pressure.By spectroscopy tests and pulse experimental results,it was concluded that the n-hexane aromatization over Pt-Zn/S-1 catalyst follows a metal-acid bifunctional mechanism.Furthermore,with the assistance of Zn,the electron-deficient Pt species in Pt-Zn/S-1 showed good sulfur tolerance performance.展开更多
The photocatalytic reduction of CO2 with H2O to fuels and chemicals using solar energy is one of the most attractive but highly difficult routes.Thus far,only a very limited number of photocatalysts has been reported ...The photocatalytic reduction of CO2 with H2O to fuels and chemicals using solar energy is one of the most attractive but highly difficult routes.Thus far,only a very limited number of photocatalysts has been reported to be capable of catalyzing the photocatalytic reduction of CO2 under visible light.The utilization of the localized surface plasmon resonance(LSPR)phenomenon is an attractive strategy for developing visible-light photocatalysts.Herein,we have succeeded in synthesizing plasmonic MoO3?x-TiO2 nanocomposites with tunable LSPR by a simple solvothermal method.The well-structured nanocomposite containing two-dimensional(2D)molybdenum oxide(MoO3?x)nanosheets and one-dimensional(1D)titanium oxide nanotubes(TiO2-NT)showed LSPR absorption band in the visible-light region,and the incorporation of TiO2-NT significantly enhanced the LSPR absorption band.The MoO3?x-TiO2-NT nanocomposite is promising for application in the photocatalytic reduction of CO2 with H2O under visible light irradiation.展开更多
Taking Rain City District of Ya’an for example, this paper based on ComGIS (Component Object Model Geographic Information System) platform takes comprehensive and systematic detection on the exposure dose of chemical...Taking Rain City District of Ya’an for example, this paper based on ComGIS (Component Object Model Geographic Information System) platform takes comprehensive and systematic detection on the exposure dose of chemical carcinogens and non-carcinogens from drinking water sources in this region and discusses health risk assessment of single factor and the whole health risk assessment. As, Hg, Cr, Pb, Cd and fluorides in some drinking water sources of Rain City District are analyzed according to Standards For Drinking Wa-ter Quality (GB5749-2006). A health risk assessment model called USEPA is also applied to drinking water health risk assessment and management countermeasure is proposed. The results show that the greatest health risk for individual person per year is caused by Cr(VI). The health risk of carcinogens is much higher than that of non-carcinogens: the greatest risk value due to non-carcinogen pollutants is caused by fluoride (F), achieving 1.05×10-8/a. The ranking of risk values due to non-carcinogen pollutants by drinking water is Pb>fluoride (F)>Hg, within Pb accounting for 44.77%, fluo-ride (F) accounting for 34.30% and Hg accounting for 20.92%. The average individual carcinogenesis annual risk of Cr(VI) is the greatest, achieving 8.91×10-4/a. The ranking of risk value due to chemical carcinogen by rural drinking water of Ya’an is Cr6+>As>Cd, within Cr6+ accounting for 91.12%, As accounting for 5.89% and Cd accounting for 3.00%. Based on this, the strategy and measures of the health risk management are put forward. This study has worked efficiently in practice. Compared with the same kind of methods which have been found, the paper has the outstanding results for the health risk assessment of the rural drinking water safety.展开更多
The unconformity surface at the bottom of the Paleogene is one of the most important migration pathways in the Sikeshu Sag of the Junggar Basin,which consists of three layers：upper coarse clastic rock,lower weatherin...The unconformity surface at the bottom of the Paleogene is one of the most important migration pathways in the Sikeshu Sag of the Junggar Basin,which consists of three layers：upper coarse clastic rock,lower weathering crust and leached zone.The upper coarse clastic rock is characterized by higher density and lower SDT and gamma-ray logging parameters,while the lower weathering crust displays opposite features.The transport coefficient of the unconformity surface is controlled by its position in respect to the basal sandstone; it is higher in the ramp region but lower in the adjacent uplifted and sag areas.The content of saturated hydrocarbons increases with the decrease of the content of nonhydrocarbons and asphaltenes.The content of benzo[c] carbazole decreases as the content of benzo[a]carbazole and [alkyl carbazole]/[alkyl ＋ benzo carbazole] increases.This suggests that the unconformity surface is an efficient medium for the transportation of hydrocarbons.展开更多
Application of biochar to agricultural soils is effective to sequester atmospheric carbon and improve soil quality, but current pyrolysis and transportation costs are high, making biochar too costly to be used at the ...Application of biochar to agricultural soils is effective to sequester atmospheric carbon and improve soil quality, but current pyrolysis and transportation costs are high, making biochar too costly to be used at the field scale. This study developed a new in-situ technique, burning and soil covering(B-SC), which can be used by farmers for production of biochar with crop residue. In this study,the air-dried feedstocks, elephant grass and corn residue, were burnt in situ for biochar production in the field. After approximately 90% of the leaves were combusted, the burning process was dramatically slowed down by covering the feedstock with soil. The biochar yield averaged 18.0 ± 1.3(n = 15) and 13.7 ± 1.3(n = 10) kg per 100 kg air-dried feedstock for the elephant grass and corn residue,respectively. The biochar properties were suitable for soil improvement. The inputs for biochar production of the B-SC process only included low labor force, open field, feedstock(e.g., grass and crop residue), and simple tools. The operation time for processing 10 kg of the corn residue by an individual farmer was 24.4 ± 4.1 min(n = 10). As compared with the conventional field burning process, the B-SC process drastically shortened the time for biomass burning and generated a significantly lower emission of smoke and thermal energy. This simple technique can be particularly practical and effective for farmers to improve the soils of poor quality in China.展开更多
The lattice dynamics,elastic properties and the origin of vanished magnetism in equiatomic quaternary Heusler compounds CoMnVZ(Z=Al,Ga)are investigated by first principle calculations in this work.Due to the similar c...The lattice dynamics,elastic properties and the origin of vanished magnetism in equiatomic quaternary Heusler compounds CoMnVZ(Z=Al,Ga)are investigated by first principle calculations in this work.Due to the similar constituent atoms in CoMnVAl and CoMnVGa compounds,they are both stable in LiMgPdSn-type structure with comparable lattice size,phonon dispersions and electronic structures.Comparatively,we find that CoMnVAl is more structurally stable than CoMnVGa.Meanwhile,the increased covalent bonding component in CoMnVAl enhances its mechanical strength and Vickers hardness,which leads to better comprehensive mechanical properties than those of CoMnVGa.Practically and importantly,structural and chemical compatibilities at the interface make non-magnetic semiconductor CoMnVAl and magnetic topological semimetals Co2MnAl/Ga more suitable to be grown in heterostructures.Owing to atomic preferential occupation in CoMnVAl/Ga,the localized atoms Mn occupy C(0.5,0.5,0.5)Wyckoff site rather than B(0.25,0.25,0.25)and D(0.75,0.75,0.75)Wyckoff sites in LiMgPdSn-type structure,which results in symmetric band filling and consequently drives them to be non-magnetic.Correspondingly,by tuning localized atoms Mn to occupy B(0.25,0.25,0.25)or/and D(0.75,0.75,0.75)Wyckoff sites in off-stoichiometric Co-Mn-V-Al/Ga compounds and keeping the total valence electrons as 24,newly compensated ferrimagnetic compounds are theoretically achieved.We hope that our work will provide more choices for spintronic applications.展开更多
Photoacoustic imaging,an emerging biomedical imaging modality,holds great promise for preclinical and clinical researches.It combines the high optical contrast and high ultrasound resolution by converting laser excita...Photoacoustic imaging,an emerging biomedical imaging modality,holds great promise for preclinical and clinical researches.It combines the high optical contrast and high ultrasound resolution by converting laser excitation into ultrasonic emission.In order to generate photoacoustic signal e±-ciently,bulky Q-switched solid-state laser systems are most commonly used as excitation sources and hence limit its commercialization.As an alternative,the miniaturized semiconductor laser system has the advantages of being inexpensive,compact,and robust,which makes a signi¯cant e®ect on production-forming design.It is also desirable to obtain a wavelength in a wide range from visible to nearinfrared spectrum for multispectral applications.Focussing on practical aspect,this paper reviews the state-of-the-art developments of low-cost photoacoustic system with laser diode and light-emitting diode excitation source and highlights a few representative installations in the past decade.展开更多
Aiming at the unsafe of water quality which is the core problem in rural drinking water safety, the study col-lected 221 water samples of rural drinking water sources in Ya'an and detected the concentrations of th...Aiming at the unsafe of water quality which is the core problem in rural drinking water safety, the study col-lected 221 water samples of rural drinking water sources in Ya'an and detected the concentrations of the car-cinogen and the non-carcinogen. Based on the analysis of water environment characteristics and the identifi-cation of water environment health risk source of Sichuan Ya’an City, which includes seven counties and a district and is the typical region of the western margin of Sichuan Basin, this study calculated and analyzed the carcinogenic risk (R) and non-carcinogenic risk (hazard index, HI) by applying the health risk model recommended by the US National Research Council of National Academy of Science. Then, taking advan-tage of the geo-statistic spatial analysis function of ArcGIS, this study analyzed the assessment result data (R and HI), selected the proper interpolation approach and educed R and HI spatial distribution maps of the study area. R and HI of the single factor and integrate factors were evaluated and thus obtained the following conclusions: For one thing, the cancerous risk indexes of the vast majority of water sources (about 94%) is the level of 10-7 and it belong to the safety extension. The main carcinogen in the water sources are As, Cr6+ and Pb, their concentrations are in the ranges of 0.004-0.01, 0.005, 0.01mg/l respectively and such water source mainly distributed in Yucheng district and Mingshan county. For another, the non-cancerous hazard indexes of the vast majority of water sources (about 98%) is also less than the limit value 1 and will not harm the local residents. The health risk of non-carcinogen comes mainly from As and fluoride, their concentra-tions are in the ranges of 0.004-0.01 and 0.1-4.2mg/l respectively. The results of the integrate factors health risk assessment showed that the total cancerous risk were still at the level of 10-6, only 12 drinking water source investigation sites (5%) exceeded the drinking water management standard value of EPA (the limit value is 10-6);the total non-cancerous hazard indexes are still in the range of 10-2-10-1, and will not harm the local residents either, only 18 drinking water source investigation sites (8%) exceeded the drinking water management standard value of EPA(the limit value is 1).The densely populated areas such as Yucheng Dis-trict, Tianquan County, Yingjing County and Shimian County are where the four contaminating materials, i.e., As, Cr6+, Pb and fluoride should be monitored with emphasis. Study results disclosed the health risk control indexes of source water quality of the studied area and thus provided the scientific basis for the water quality control of water sources. This study had worked efficiently in practice. Compared with the same kind of methods which had been found, the paper had the outstanding results for the health risk assessment of the rural drinking water safety.展开更多
The structure of Ni active sites supported on amorphous silica-alumina supports with different contents of Al_(2)O_(3)loadings in relation to their activities in ethylene oligomerization were investigated.Two kinds of...The structure of Ni active sites supported on amorphous silica-alumina supports with different contents of Al_(2)O_(3)loadings in relation to their activities in ethylene oligomerization were investigated.Two kinds of Ni sites were detected by in situ FTIR-CO and H_(2)-TPR experiments,that are Ni^(2+)cations as grafted on weak acidic silanols and Ni^(2+)cations at ion-exchange positions.The ethylene oligomerization activities of these Ni/ASA catalysts were found an ascending tendency as the Al_(2)O_(3)loading decreased,which could be attributed to the enriched concentration of Ni^(2+)species on acidic silanols with a weaker interaction with the amorphous silica-alumina support.These Ni^(2+)species were more easily to be evolved into Ni^(+)species,which has been identified to be the active sites of ethylene oligomerization.Thus,it seems reasonable to conclude that Ni^(2+)species grafted on acidic silanols were the precursors of active sites.展开更多
Nuclear RNA export into the cytoplasm is one of the key steps in protein expression to realize biological functions.Despite the broad availability of nucleic acid dyes,tracking and quantifying the highly dynamic proce...Nuclear RNA export into the cytoplasm is one of the key steps in protein expression to realize biological functions.Despite the broad availability of nucleic acid dyes,tracking and quantifying the highly dynamic process of RNA export in live cells is challenging.When dye-labeled RNA enters the cytoplasm,the dye molecules are released upon degradation of the RNA,allowing them to re-enter the cell nucleus.As a result,the ratio between the dye exported with RNA into the cytoplasm and the portion staying inside the nucleus cannot be determined.To address this common limitation,we report the design of a smart probe that can only check into the nucleus once.When adding to cells,this probe rapidly binds with nuclear RNAs in live cells and reacts with intrinsic H_(2)S.This reaction not only activates the fluorescence for RNA tracking but also changes the structure of probe and consequently its intracellular localization.After disassociating from exported RNAs in cytoplasm,the probe preferentially enters lysosomes rather than cell nucleus,enabling real-time quantitative measurement of nuclear RNA exports.Using this probe,we successfully evaluated the effects of hormones and cancer drugs on nuclear RNA export in live cells.Interestingly,we found that hormones inhibiting RNA exports can partially offset the effect of chemotherapy.展开更多
Water level variations have caused numerous dam slope collapse disasters around the world,illustrating the large influence of water level fluctuations on dam slopes.The required indoor tests were conducted and a numer...Water level variations have caused numerous dam slope collapse disasters around the world,illustrating the large influence of water level fluctuations on dam slopes.The required indoor tests were conducted and a numerical model of an actual earth-filled dam was constructed to investigate the influences of the water level fluctuation rate and the hysteresis of the soil-water characteristic curve(SWCC)on the stability of the upstream dam slope.The results revealed that the free surface in the dam body for the desorption SWCC during water level fluctuations was higher than that for the adsorption SWCC,which would be more evident at higher water levels.The safety factor of the upstream dam slope initially decreased and then increased for the most dangerous water level as the water level rose and fell.The water level fluctuation rate mainly influenced the initial section of the safety factor variation curve,while the SWCC hysteresis mainly affected the minimum safety factor of the water level fluctuations.The desorption SWCC is suggested for engineering design.Furthermore,a quick prediction method is proposed to estimate the safety factor of upstream dam slopes with identical structures.展开更多
基金Joint Project of Dalian University of Technology-Dalian Institute of Chemical Physics (HX20230236)。
文摘Zeolite nanosheets with a short b-axis thickness are highly desirable in lots of catalytic reactions due to their reduced diffusion resistance. Nevertheless, conventional synthesis methods usually require expensive structure-directing agents(SDAs), pricey raw materials, and eco-unfriendly fluorine-containing additives. Here, we contributed a cost-effective and fluoride-free synthesis method for synthesizing high-quality MFI zeolite nanosheets through a Silicalite-1(Sil-1) seed suspension and urea cooperative strategy, only with inexpensive colloidal silica as the Si source. Our approach was effective for synthesizing both Sil-1 and aluminum-containing ZSM-5 nanosheets. By optimizing key synthesis parameters,including seed aging time, seed quantity, and urea concentration, we achieved precise control over the crystal face aspect ratio and b-axis thickness. We also revealed a non-classical oriented nanosheet growth mechanism, where Sil-1 seeds induced the formation of quasi-ordered precursor particles, and the(010)crystal planes of these particles facilitated urea adsorption, thereby promoting c-axis-oriented growth.The obtained ZSM-5 nanosheets exhibited exceptional catalytic performance in the benzene alkylation with ethanol, maintaining stability for over 500 h, which is 5 times longer than traditional ZSM-5 catalysts. Furthermore, large-scale production of ZSM-5 nanosheets was successfully carried out in a 3 L highpressure autoclave, yielding samples consistent with those from laboratory-scale synthesis. This work marks a significant step forward in the sustainable and efficient production of MFI nanosheets using inexpensive and environmentally friendly raw materials, offering the broad applicability in catalysis.
基金supported by the Youth Foundation of Beijing Academy of Agriculture and Forestry Sciences[Grant No.QNJJ202242]the Excellent Young Scholars of Beijing Academy of Agriculture and Forestry Sciences[Grant No.YXQN202205]+3 种基金the Beijing Nova Program[Grant No.20220484052]the National Natural Science Foundation of China[Grant No.31801852]the Collaborative Innovation Center of Beijing Academy of Agriculture and Forestry Sciences[Grant No.KJCX201907-2]the Earmarked Fund for China Agriculture Research System[Grant No.CARS-23-A-05].
文摘The soil-resident pathogen, Plasmodiophora brassicae, infects cruciferous crops, causing obligate parasitic clubroot disease and posing a significant threat to the Brassica vegetable industry in China. To learn more about its pathogenesis, we reported a Nanopore sequencing-derived25.3 Mb high-quality genome sequence of P. brassicae pathotype 4 strain(P.b 4). Comparing the P.b 4 genome with that of the published P.brassicae e3 genome(P.b e3) identified single nucleotide polymorphisms, structural variations, and small insertions and deletions. We then carried out RNA-sequencing of root samples from a clubroot-susceptible line at 5, 14, and 28 days after inoculation(DAI), and classified genes into five categories based on their expression patterns. Interestingly, 158 genes were highly expressed at 14 DAI, which were enriched in budding cell isotropic bud growth, ascospore wall assembly, spore wall assembly, spore wall biogenesis, and ascospore wall biogenesis.Subsequently, we bioinformatically predicted 555 secreted effector candidates, among which only 125 were expressed during infection and had amino acid lengths less than 400. The putative effector Pb010018, which was highly expressed at 14 DAI, was validated to have a signal peptide using a yeast secretion system. Luciferase activity and co-immunoprecipitation assays demonstrated that Pb010018 interacts with serine hydroxymethyltransferase BrSHMT1, and expression analysis showed that SHMT1 was upregulated in both Arabidopsis and B. rapa during infection. Furthermore, after infection, the Arabidopsis shmt1 mutant(atshmt1) showed reduced severity of clubroot disease, together with downregulated expression of Pb010018. Our results offer new insights into plant-pathogen interaction mechanisms, and provide the possibility for improving Brassica resistance to clubroot disease.
基金supported by the Intelligence of Electrical Equipment of the Hebei University of Technology(No.EERI_OY2021006)the Overseas Scientists Sponsorship Program of Hebei Province(No.C20230320)the S&T Program of Hebei(No.225676163GH).
文摘The identification of fully spin-polarized topological phases in magnetic inorganic materials has attracted significant attention.In this study,through first-principles calculations,we characterize CrCl_(2)(pyz)_(2),a metal-organic framework(MOF),as a nodal chain semimetal.Our results reveal a ferromagnetic ground state in this material,presenting as a half-metal with a single spin channel near the Fermi level.Specifically,the spin-down states form a nodal chain close to the Fermi level,consisting of three nodal loops protected by glide mirror symmetry on distinct planes.Furthermore,fully spin-polarized drumhead surface states corresponding to these nodal loops are identified on the material’s surfaces.Remarkably,we observe the persistence of the fully spin-polarized nodal chain even when tuning the ligand rotation an-gle of the MOF.Furthermore,our investigation delves into the influence of spin-orbit coupling(SOC)on the system,revealing that it has minimal impact on the nodal chain.The robustness of the nodal chain in the presence of SOC underscores its intriguing and resilient nature,indicating its potential utility in various electronic applications.Ultimately,the robust realization of a fully spin-polarized nodal chain in this magnetic MOF system holds promise for applications in the realm of spintronics.
基金financially supported by the Guangdong Pearl River Talent Program(2021ZT09L400)the National Natural Science Foundation of China(52302195,52072284)+1 种基金the Joint Funds of Natural Science Foundation of Hubei Province(2022CFD087)the Scientific Research and Technology Development Project of China National Petroleum Corporation(Grant Nos.2024ZG50)。
文摘The utilization of self-assembled monolayers(SAMs)has significantly elevated the power conversion efficiency(PCE)of inverted perovskite solar cells(PSCs).However,the inherent hydrophobicity of these SAMs poses challenges in the subsequent printing of perovskite films in PSC upscaling.In this work,we incorporated a multifunctional additive,dimethyl suberimidate dihydrochloride(DMSCl_(2)),into the perovskite precursor to enhance the quality of the blade-coated perovskite film on the SAM interlayer.Characterizations revealed that the function groups of the imino(N-H)and methoxy(CH_(3)O-)DMSCl_(2) facilitate both bonding between perovskite precursor and SAM molecule(Me-4PACz),which facilitates the large-area printing of perovskite film.These interactions also provide effective passivation within the perovskite films and interface defects of PSCs.As a result,a significantly enhanced PCE from 16.62% to 20.37% was obtained for the printed perovskite solar module(93.10 cm^(2))and 25.27% for the small device(0.09 cm^(2)).Remarkable stability was achieved with 93.3% of their initial PCE after 1000 h of continuous maximum power point(MPP)tracking.This report suggests that multifunctional additive doping provides a convenient route for the upscaling of perovskite solar cells with SAM interlayers.
基金support from the China Postdoc-toral Science Foundation(No.2023M730905)Hebei Province High-level Talent Funding Project(No.A20231001)Scientific Research Fund of Dezhou University(No.2022xjrc407).
文摘A glassy(G)phase was formed for Zr-rich Zr70-75(Al,Ni,Cu,Ag)25-30(atomic percent,at.%)melt-spun alloy ribbons.These glassy alloys exhibit the glass transition,followed by a supercooled liquid region and then three-stage crystallization.The glass transition temperature and the onset temperature for the first-stage crystallization(Tx1)decrease from 630 to 668 K,respectively for the 70Zr alloy to 619 and 652 K,respectively for the 75Zr alloy.The first-stage exothermic peak is due to the precipitation of an icosahedral quasicrystal(IQ)phase.The IQ particle size decreases from 10 nm to 6 nm with increasing Zr content from 70 at.%to 74 at.%.The[G+IQ]phases change to Zr2 Ni+Zr2(Cu,Ag)phases after the second exothermic peak and then Zr2 Ni+Zr2(Cu,Ag)+Zr5 Al3 phases after the third stage.It is noticed that the as-spun glassy alloy ribbons as well as the annealed[G+IQ]phase ribbons exhibit good bending plasticity.Furthermore,the 70Zr thicker ribbons also exhibit high tensile fracture strength of 1090-1187 MPa and plastic elongation of 0.17%-0.42%.The fracture mode is similar to that of ordinary bulk metallic glasses.The Vickers hardness(H v)is 480 for 70Zr alloy and decreases to 436 for 75Zr alloy.The precipitation of IQ phase causes a significant increase in H v to about 554.The formations of glassy alloys with high Zr contents of 70 at.%-75 at.%by melt spinning as well as the[G+IQ]phase alloys with good bending plasticity by annealing hold promise for the creation of a new type of engineering material,transcending mere academic novelty.
基金supported by the National Natural Science Foundation of China(Grant Nos.12488201 by X.J.Z.,12374066 by L.Z.,and 12374154 by X.T.L.)the National Key Research and Development Program of China(Grant Nos.2021YFA1401800 by X.J.Z.,2022YFA1604200 by L.Z.,2022YFA1403900 by G.D.L.and 2023YFA1406000by X.T.L.)+3 种基金the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(Grant No.XDB25000000by X.J.Z.)Innovation Program for Quantum Science and Technology(Grant No.2021ZD0301800 by X.J.Z.)the Youth Innovation Promotion Association of CAS(Grant No.Y2021006 by L.Z.)the Synergetic Extreme Condition User Facility(SECUF)。
文摘The doping evolution of the nodal electron dynamics in the trilayer cuprate superconductor Bi_(2)Sr_(2)Ca_(2)Cu_(3)O_(10+δ)(Bi2223)is investigated using high-resolution laser-based angle-resolved photoemission spectroscopy(ARPES).Bi2223single crystals with different doping levels are prepared by controlled annealing,which cover the underdoped,optimallydoped and overdoped regions.The electronic phase diagram of Bi2223 is established which describes the Tcdependence on the sample doping level.The doping dependence of the nodal Fermi momentum for the outer(OP)and inner(IP)CuO_(2)planes is determined.Charge distribution imbalance between the OP and IP CuO_(2)planes is quantified,showing enhanced disparity with increasing doping.Nodal band dispersions demonstrate a prominent kink at~94 meV in the IP band,attributed to the unique Cu coordination in the IP plane,while a weaker~60 meV kink is observed in the OP band.The nodal Fermi velocity of both OP and IP bands is nearly constant at~1.62 eV·A independent of doping.These results provide important information to understand the origin of high Tcand superconductivity mechanism in high temperature cuprate superconductors.
文摘Background: Trans-province transfer of the patients has been successfully carried out and has greatly relieved the burden of the hospitals in Sichuan Province after Sichuan earthquake. The aim of the study was to retrospectively analyze the efficacy and feasibility of the trans-province transfer of the multiple trauma patients after Sichuan earthquake. Methods: A retrospective and descriptive analysis was conducted based on the medical records of the multiple trauma patients (ISS ≥ 16) transferred to the Grade 3A hospitals outside Sichuan province. The patients were divided into two groups based on the distance to Sichuan province, i.e., Group A (the seismic patients transferred to Chongqing) and Group B (the seismic patients transferred to the other provinces/ municipalities). A comparison was done in aspects of distance of transfer, time from injury to transfer, vital signs, the infection rates (at transfer and on discharge), injury severity and prognostic indices (cure rate, disability rate and mortality). Results: The distance between Chengdu and the other places was at a wide range of 313 - 1653 km, whereas the time from injury to transfer showed no statistical difference between groups (P > 0.05). There were no significant differences between both groups with respects to patient demographics, injury mechanism, time from injury to transfer, vital signs, infection rate and injury severity. The prognostic indices showed no significant difference, except for FIM scores (P < 0.05). Conclusions: The results of the study indicate that the different distance of the transfer of the multiple trauma patients does not aggravate the severity or deteriorate the prognosis, which proves that the medical supportive transfer system is acceptable, effective and worthy of further implementation in China, which may be ascribed to the advanced transportation system and high level of therapeutic capacity of the hospitals. In the meantime, attention should be paid to psychological intervention and functional rehabilitation during the treatment of the transferred seismic patients.
基金financially supported by the National Natural Science Foundation of China (21603023)
文摘Platinum(Pt)supported on Zinc(Zn)modified silicalite-1(S-1)zeolite(denoted as Pt-Zn/S-1)was prepared by using a wetness-impregnation method and applied in the n-hexane aromatization reaction for the first time.Both Lewis and Bronsted acid sites were detected in Pt-Zn/S-1 catalyst by means of FT-IR adsorption of NH3 experiment,which were identified as mostly weak and medium ones.Besides,Pt and Zn species showed strong interaction,as revealed by the TPR(Temperature-programmed reduction)and XPS(X-ray photoelectron spectroscopy)experiments.Pt-Zn/S-1 catalyst exhibited excellent aromatization function rather than isomerization and cracking side reactions in the conversion of n-hexane.Pulse experimental study showed that 75.6%of n-hexane conversion and 76.8%of benzene selectivity were obtained over Pt0.1-Zn60/S-l catalyst at 550℃ and under atmospheric pressure.By spectroscopy tests and pulse experimental results,it was concluded that the n-hexane aromatization over Pt-Zn/S-1 catalyst follows a metal-acid bifunctional mechanism.Furthermore,with the assistance of Zn,the electron-deficient Pt species in Pt-Zn/S-1 showed good sulfur tolerance performance.
文摘The photocatalytic reduction of CO2 with H2O to fuels and chemicals using solar energy is one of the most attractive but highly difficult routes.Thus far,only a very limited number of photocatalysts has been reported to be capable of catalyzing the photocatalytic reduction of CO2 under visible light.The utilization of the localized surface plasmon resonance(LSPR)phenomenon is an attractive strategy for developing visible-light photocatalysts.Herein,we have succeeded in synthesizing plasmonic MoO3?x-TiO2 nanocomposites with tunable LSPR by a simple solvothermal method.The well-structured nanocomposite containing two-dimensional(2D)molybdenum oxide(MoO3?x)nanosheets and one-dimensional(1D)titanium oxide nanotubes(TiO2-NT)showed LSPR absorption band in the visible-light region,and the incorporation of TiO2-NT significantly enhanced the LSPR absorption band.The MoO3?x-TiO2-NT nanocomposite is promising for application in the photocatalytic reduction of CO2 with H2O under visible light irradiation.
文摘Taking Rain City District of Ya’an for example, this paper based on ComGIS (Component Object Model Geographic Information System) platform takes comprehensive and systematic detection on the exposure dose of chemical carcinogens and non-carcinogens from drinking water sources in this region and discusses health risk assessment of single factor and the whole health risk assessment. As, Hg, Cr, Pb, Cd and fluorides in some drinking water sources of Rain City District are analyzed according to Standards For Drinking Wa-ter Quality (GB5749-2006). A health risk assessment model called USEPA is also applied to drinking water health risk assessment and management countermeasure is proposed. The results show that the greatest health risk for individual person per year is caused by Cr(VI). The health risk of carcinogens is much higher than that of non-carcinogens: the greatest risk value due to non-carcinogen pollutants is caused by fluoride (F), achieving 1.05×10-8/a. The ranking of risk values due to non-carcinogen pollutants by drinking water is Pb>fluoride (F)>Hg, within Pb accounting for 44.77%, fluo-ride (F) accounting for 34.30% and Hg accounting for 20.92%. The average individual carcinogenesis annual risk of Cr(VI) is the greatest, achieving 8.91×10-4/a. The ranking of risk value due to chemical carcinogen by rural drinking water of Ya’an is Cr6+>As>Cd, within Cr6+ accounting for 91.12%, As accounting for 5.89% and Cd accounting for 3.00%. Based on this, the strategy and measures of the health risk management are put forward. This study has worked efficiently in practice. Compared with the same kind of methods which have been found, the paper has the outstanding results for the health risk assessment of the rural drinking water safety.
基金fnancially supported by the National Key Project of Science and Technology for Development of Large-size Oil&Gas Fields and Coal-bed Gas(Grant No.2008ZX05003-002)by the State Key Laboratory of Petroleum Resources and Prospecting(No.prp2009-02)The study is a contribution to IGCP#592 Project
文摘The unconformity surface at the bottom of the Paleogene is one of the most important migration pathways in the Sikeshu Sag of the Junggar Basin,which consists of three layers：upper coarse clastic rock,lower weathering crust and leached zone.The upper coarse clastic rock is characterized by higher density and lower SDT and gamma-ray logging parameters,while the lower weathering crust displays opposite features.The transport coefficient of the unconformity surface is controlled by its position in respect to the basal sandstone; it is higher in the ramp region but lower in the adjacent uplifted and sag areas.The content of saturated hydrocarbons increases with the decrease of the content of nonhydrocarbons and asphaltenes.The content of benzo[c] carbazole decreases as the content of benzo[a]carbazole and [alkyl carbazole]/[alkyl ＋ benzo carbazole] increases.This suggests that the unconformity surface is an efficient medium for the transportation of hydrocarbons.
基金supported by the National Natural Science Foundation of China (No. 41271363)
文摘Application of biochar to agricultural soils is effective to sequester atmospheric carbon and improve soil quality, but current pyrolysis and transportation costs are high, making biochar too costly to be used at the field scale. This study developed a new in-situ technique, burning and soil covering(B-SC), which can be used by farmers for production of biochar with crop residue. In this study,the air-dried feedstocks, elephant grass and corn residue, were burnt in situ for biochar production in the field. After approximately 90% of the leaves were combusted, the burning process was dramatically slowed down by covering the feedstock with soil. The biochar yield averaged 18.0 ± 1.3(n = 15) and 13.7 ± 1.3(n = 10) kg per 100 kg air-dried feedstock for the elephant grass and corn residue,respectively. The biochar properties were suitable for soil improvement. The inputs for biochar production of the B-SC process only included low labor force, open field, feedstock(e.g., grass and crop residue), and simple tools. The operation time for processing 10 kg of the corn residue by an individual farmer was 24.4 ± 4.1 min(n = 10). As compared with the conventional field burning process, the B-SC process drastically shortened the time for biomass burning and generated a significantly lower emission of smoke and thermal energy. This simple technique can be particularly practical and effective for farmers to improve the soils of poor quality in China.
基金Project supported by Special Fund for Introduced Talent to Initiate Scientific Research in Nanjing Tech Universitythe National Natural Science Foundation of China (Grant Nos. 51831003 and 51771225)
文摘The lattice dynamics,elastic properties and the origin of vanished magnetism in equiatomic quaternary Heusler compounds CoMnVZ(Z=Al,Ga)are investigated by first principle calculations in this work.Due to the similar constituent atoms in CoMnVAl and CoMnVGa compounds,they are both stable in LiMgPdSn-type structure with comparable lattice size,phonon dispersions and electronic structures.Comparatively,we find that CoMnVAl is more structurally stable than CoMnVGa.Meanwhile,the increased covalent bonding component in CoMnVAl enhances its mechanical strength and Vickers hardness,which leads to better comprehensive mechanical properties than those of CoMnVGa.Practically and importantly,structural and chemical compatibilities at the interface make non-magnetic semiconductor CoMnVAl and magnetic topological semimetals Co2MnAl/Ga more suitable to be grown in heterostructures.Owing to atomic preferential occupation in CoMnVAl/Ga,the localized atoms Mn occupy C(0.5,0.5,0.5)Wyckoff site rather than B(0.25,0.25,0.25)and D(0.75,0.75,0.75)Wyckoff sites in LiMgPdSn-type structure,which results in symmetric band filling and consequently drives them to be non-magnetic.Correspondingly,by tuning localized atoms Mn to occupy B(0.25,0.25,0.25)or/and D(0.75,0.75,0.75)Wyckoff sites in off-stoichiometric Co-Mn-V-Al/Ga compounds and keeping the total valence electrons as 24,newly compensated ferrimagnetic compounds are theoretically achieved.We hope that our work will provide more choices for spintronic applications.
基金the National Natural Scienti¯c Foundation of China(11664011,11304129)the Science and Technology Program of Jiangxi,China(20151BAB217025,20132BBG70033,GJJ150790)the Intramural Top-notch Youth Talent Program of JXSTNU,China(2013QNBJRC003).
文摘Photoacoustic imaging,an emerging biomedical imaging modality,holds great promise for preclinical and clinical researches.It combines the high optical contrast and high ultrasound resolution by converting laser excitation into ultrasonic emission.In order to generate photoacoustic signal e±-ciently,bulky Q-switched solid-state laser systems are most commonly used as excitation sources and hence limit its commercialization.As an alternative,the miniaturized semiconductor laser system has the advantages of being inexpensive,compact,and robust,which makes a signi¯cant e®ect on production-forming design.It is also desirable to obtain a wavelength in a wide range from visible to nearinfrared spectrum for multispectral applications.Focussing on practical aspect,this paper reviews the state-of-the-art developments of low-cost photoacoustic system with laser diode and light-emitting diode excitation source and highlights a few representative installations in the past decade.
文摘Aiming at the unsafe of water quality which is the core problem in rural drinking water safety, the study col-lected 221 water samples of rural drinking water sources in Ya'an and detected the concentrations of the car-cinogen and the non-carcinogen. Based on the analysis of water environment characteristics and the identifi-cation of water environment health risk source of Sichuan Ya’an City, which includes seven counties and a district and is the typical region of the western margin of Sichuan Basin, this study calculated and analyzed the carcinogenic risk (R) and non-carcinogenic risk (hazard index, HI) by applying the health risk model recommended by the US National Research Council of National Academy of Science. Then, taking advan-tage of the geo-statistic spatial analysis function of ArcGIS, this study analyzed the assessment result data (R and HI), selected the proper interpolation approach and educed R and HI spatial distribution maps of the study area. R and HI of the single factor and integrate factors were evaluated and thus obtained the following conclusions: For one thing, the cancerous risk indexes of the vast majority of water sources (about 94%) is the level of 10-7 and it belong to the safety extension. The main carcinogen in the water sources are As, Cr6+ and Pb, their concentrations are in the ranges of 0.004-0.01, 0.005, 0.01mg/l respectively and such water source mainly distributed in Yucheng district and Mingshan county. For another, the non-cancerous hazard indexes of the vast majority of water sources (about 98%) is also less than the limit value 1 and will not harm the local residents. The health risk of non-carcinogen comes mainly from As and fluoride, their concentra-tions are in the ranges of 0.004-0.01 and 0.1-4.2mg/l respectively. The results of the integrate factors health risk assessment showed that the total cancerous risk were still at the level of 10-6, only 12 drinking water source investigation sites (5%) exceeded the drinking water management standard value of EPA (the limit value is 10-6);the total non-cancerous hazard indexes are still in the range of 10-2-10-1, and will not harm the local residents either, only 18 drinking water source investigation sites (8%) exceeded the drinking water management standard value of EPA(the limit value is 1).The densely populated areas such as Yucheng Dis-trict, Tianquan County, Yingjing County and Shimian County are where the four contaminating materials, i.e., As, Cr6+, Pb and fluoride should be monitored with emphasis. Study results disclosed the health risk control indexes of source water quality of the studied area and thus provided the scientific basis for the water quality control of water sources. This study had worked efficiently in practice. Compared with the same kind of methods which had been found, the paper had the outstanding results for the health risk assessment of the rural drinking water safety.
文摘The structure of Ni active sites supported on amorphous silica-alumina supports with different contents of Al_(2)O_(3)loadings in relation to their activities in ethylene oligomerization were investigated.Two kinds of Ni sites were detected by in situ FTIR-CO and H_(2)-TPR experiments,that are Ni^(2+)cations as grafted on weak acidic silanols and Ni^(2+)cations at ion-exchange positions.The ethylene oligomerization activities of these Ni/ASA catalysts were found an ascending tendency as the Al_(2)O_(3)loading decreased,which could be attributed to the enriched concentration of Ni^(2+)species on acidic silanols with a weaker interaction with the amorphous silica-alumina support.These Ni^(2+)species were more easily to be evolved into Ni^(+)species,which has been identified to be the active sites of ethylene oligomerization.Thus,it seems reasonable to conclude that Ni^(2+)species grafted on acidic silanols were the precursors of active sites.
基金supported by the National Natural Science Foundation of China(Nos.21775001,21874137,21974001,21976183and 22074001)Natural Science Foundation of Anhui Province(No.1808085MB32)Nature and Science Foundation from Anhui Province Ministry of Education(No.KJ2019A0011)。
文摘Nuclear RNA export into the cytoplasm is one of the key steps in protein expression to realize biological functions.Despite the broad availability of nucleic acid dyes,tracking and quantifying the highly dynamic process of RNA export in live cells is challenging.When dye-labeled RNA enters the cytoplasm,the dye molecules are released upon degradation of the RNA,allowing them to re-enter the cell nucleus.As a result,the ratio between the dye exported with RNA into the cytoplasm and the portion staying inside the nucleus cannot be determined.To address this common limitation,we report the design of a smart probe that can only check into the nucleus once.When adding to cells,this probe rapidly binds with nuclear RNAs in live cells and reacts with intrinsic H_(2)S.This reaction not only activates the fluorescence for RNA tracking but also changes the structure of probe and consequently its intracellular localization.After disassociating from exported RNAs in cytoplasm,the probe preferentially enters lysosomes rather than cell nucleus,enabling real-time quantitative measurement of nuclear RNA exports.Using this probe,we successfully evaluated the effects of hormones and cancer drugs on nuclear RNA export in live cells.Interestingly,we found that hormones inhibiting RNA exports can partially offset the effect of chemotherapy.
基金funded by the Key R&D Program of Science and Technology Bureau of Shangluo City(Grant No.2020-Z-0111)Scientific Research Program of Science and Technology Department of Shaanxi Province(Grant No.2021JQ-844).
文摘Water level variations have caused numerous dam slope collapse disasters around the world,illustrating the large influence of water level fluctuations on dam slopes.The required indoor tests were conducted and a numerical model of an actual earth-filled dam was constructed to investigate the influences of the water level fluctuation rate and the hysteresis of the soil-water characteristic curve(SWCC)on the stability of the upstream dam slope.The results revealed that the free surface in the dam body for the desorption SWCC during water level fluctuations was higher than that for the adsorption SWCC,which would be more evident at higher water levels.The safety factor of the upstream dam slope initially decreased and then increased for the most dangerous water level as the water level rose and fell.The water level fluctuation rate mainly influenced the initial section of the safety factor variation curve,while the SWCC hysteresis mainly affected the minimum safety factor of the water level fluctuations.The desorption SWCC is suggested for engineering design.Furthermore,a quick prediction method is proposed to estimate the safety factor of upstream dam slopes with identical structures.
