The induction of antitumor immunity by tumor antigens released from cancer cells following regional photothermal therapy(PTT)alone may not be adequate for achieving complete tumor elimination.Combination therapy with ...The induction of antitumor immunity by tumor antigens released from cancer cells following regional photothermal therapy(PTT)alone may not be adequate for achieving complete tumor elimination.Combination therapy with immune adjuvants enhances antitumor immune responses,but faces challenges such as targeting deficiencies,systemic toxicity,and uncontrolled release behavior.Herein,we introduce a novel dual-functional hybrid membrane nanoparticle(HM-NP)incorporating gold nanorods(GNRs)and a thermally responsive polymer shell.HM-NP demonstrates exceptional homotypic targeting efficacy beneath the tumor cell membrane(TM),leading to substantial tumor accumulation.Upon in situ near-infrared(NIR)stimulation,GNRs within HM-NP generate heat,triggering the burst release of HM by facilitating the contraction and disintegration of the thermally responsive polymer shell.HM-NP exhibits excellent photothermal conversion efficiency under NIR irradiation,enabling effective destruction of primary tumors,release of tumor-associated antigens,and stimulation of potent anti-cancer immune.Simultaneously,the immune responses are strengthened by TM and Escherichia coli membrane(EM)through promoting the maturation of antigen presenting cells(APCs)and activating cytotoxic T lymphocytes(CTLs).Moreover,the use of polymer shells enables efficient cancer therapy with minimal host clearance and adverse effects.This photothermally triggered immunotherapy holds promise for precise and personalized treatment of tumors.展开更多
Kagome magnets Tb Mn_(6)Sn_(6-x)In_(x)(x=0-1.2)exhibit a robust anomalous Hall effect(AHE)that persists above room temperature,demonstrating significant potential for high-temperature spintronics applications.At eleva...Kagome magnets Tb Mn_(6)Sn_(6-x)In_(x)(x=0-1.2)exhibit a robust anomalous Hall effect(AHE)that persists above room temperature,demonstrating significant potential for high-temperature spintronics applications.At elevated temperatures,a spin-reorientation transition induces a ferrimagnetic state(FIM1)with in-plane magnetic moments,accompanied by a nonmonotonic Hall response that differs markedly from the low-temperature behavior.Upon indium doping,the long-range ferrimagnetic transition is progressively suppressed to lower temperatures,along with a noticeable reduction in magnetic anisotropy.Interestingly,at a doping level of x=1.2,the FIM1 state observed in the parent compound is completely eliminated.These systematic changes in magnetic ordering and transport properties underscore a coherent evolution of the electronic and magnetic states with doping,offering critical insights into the interplay among lattice structure,magnetism,and electronic behavior in kagome lattices.展开更多
The van der Waals cluster magnet Nb_(3)Cl_(8)has recently been shown to possibly host a quantum-spin-liquid ground state.The Nb ions in this compound form a breathing kagome structure,where the magnetic moment comes f...The van der Waals cluster magnet Nb_(3)Cl_(8)has recently been shown to possibly host a quantum-spin-liquid ground state.The Nb ions in this compound form a breathing kagome structure,where the magnetic moment comes from three nearest Nb ions forming a molecular cluster with spin 1/2.Previous bulk measurements including magnetic susceptibility and specific heat suggested the existence of spinon Fermi surfaces.Here we further probe the spin system by nuclear magnetic resonance(NMR)and muon spin rotation and relaxation(μSR)techniques.We confirm that there is no magnetic long-range order and the dynamical spin fluctuations persist down to 0.075 K.These results provide further evidence that Nb_(3)Cl_(8)may host a quantum spin liquid.展开更多
The Terreneuvian Epoch（541-521 Ma）is also an important period for metallogenesis in South China, as was represented by the widespread occurrences of Ni-Mo polymetallic layers on the antecedent shallow platform margi...The Terreneuvian Epoch（541-521 Ma）is also an important period for metallogenesis in South China, as was represented by the widespread occurrences of Ni-Mo polymetallic layers on the antecedent shallow platform margin and the V-enriched black shales in deeper slope-basin settings. In this study, we have measured Re-Os isochron ages of Ni-Mo polymetallic layers（Songlin, Niuchang, Sancha, Chuanpengwan）, V-rich black shales（Bahuang）, and non-metalliferous black shales（Shuidong） in the basal Niutitang Formation in Guizhou and Hunan province, South China. The Ni-Mo polymetallic layers and V-enriched black shales have similar Re-Os isochron ages, suggesting concurrent deposition of these two types of metalliferous ores. This suggestion is consistent with the traditional stratigraphic correlation by using the nodular phosphorite bed directly underlying these metalliferous layers as a stratigraphic marker. Furthermore, the metalliferous ores and non-metalliferous black shales have similar initial ^（187）Os/^（188） Os ratios of 0.8-0.9, arguing for a dominant seawater origin with minor contribution of hydrothermal activity. Furthermore, Re-Os isotopic data also imply that Ni-Mo and V ore might have derived from the same source. We suggest that the spatial distribution of metalliferous ores can be explained by the development of non-sulfidic anoxic-suboxic wedge（NSASW） in the slope-basin and sulfidic wedge in the previous platform margin. Upwelling of deep water first transects the mildly reduced, organic rich NSASW, in which V（V） is reduced to V（IV）, and is preferentially removed from seawater by organometallic complex formation. As a result, V-rich black shale deposits in the slope-basin of Yangtze Platform. Further movement of deep water into the sulfidic platform margin results in Ni-Mo polymetallic layer formation.展开更多
Iron and manganese are the important redoxsensitive elements in the ocean. Previous studies have established a series of paleo-depositional redox proxies based on the form and content of iron in sedimentary rocks(e.g....Iron and manganese are the important redoxsensitive elements in the ocean. Previous studies have established a series of paleo-depositional redox proxies based on the form and content of iron in sedimentary rocks(e.g., degree of pyritization, FeHR/FeT, Fe/Al). These proxies were developed and applied on siliciclastic-rich marine sediments. Although marine carbonate rocks are generally considered to preserve the geochemical signals of ancient seawater, neither Fe nor Mn content in marine carbonate rocks(Fecarb, Mncarb) has been independently used as a proxy to quantify environmental cues in paleo-oceans. Both Fe and Mn are insoluble in oxic conditions(Fe_2O_3, Fe(OH)_3,MnO_2), while their reduced forms(Fe^(2+) and Mn^(2+)) are soluble. Therefore, oxic seawater should have low concentrations of dissolved Fe^(2+)and Mn^(2+), and accordingly carbonate rocks precipitated from oxic seawater should have low Fecarband Mncarb, and vice versa. To evaluate whether Fecarband Mncarbcan be used to quantify oxygen fugacity in seawater, we measured Fecarband Mncarbof Upper Devonian marine carbonate rocks collected from nine sections in South China. Fecarbof intraplatform basin samples wassignificantly higher than that of shelf samples, while shelf and basin samples had comparable Mncarb. The modeling result indicates that the dramatic difference in Fecarbcannot be explained by variation in oxygen fugacity between the shelf and basin seawater. Instead, both Fecarband Mncarb appear to be more sensitive to benthic flux from sediment porewater that is enriched in Fe^(2+)and Mn^(2+). Porewater Fe^(2+)and Mn^(2+)derive from bacterial iron and manganese reduction; flux was controlled by sedimentation rate and the depth of the Fe(Mn) reduction zone in sediments, the latter of which is determined by oxygen fugacity at the water–sediment interface. Thus, high Fecarbof the basin samples might be attributed to low sedimentation rate and/or low oxygen fugacity at the seafloor. However, invariant Mncarbof the shelf and basin samples might be the consequence of complete reduction of Mn in sediments. Our study indicates that marine carbonate rocks may not necessarily record seawater composition, particularly for benthic carbonate rocks. The influence of benthic flux might cause carbonate rocks' geochemical signals to deviate significantly from seawater values. Our study suggests that interpretation of geochemical data from carbonate rocks, including carbonate carbon isotopes, should consider the process of carbonate formation.展开更多
Global occurrences of Steptoean Positive Carbon Isotope Excursion（SPICE） during Late Cambrian recorded a significant perturbation in marine carbon cycle, and might have had profound impacts on the biological evoluti...Global occurrences of Steptoean Positive Carbon Isotope Excursion（SPICE） during Late Cambrian recorded a significant perturbation in marine carbon cycle, and might have had profound impacts on the biological evolution. In previous studies, SPICE has been reported from the Jiangnan slope belt in South China. To evaluate the bathymetric extent of SPICE, we investigate the limestone samples from the upper Qingxi Formation in the Shaijiang Section in the Jiangnan Basin. Our results show the positive excursions for both carbonate carbon（δ^（13）C） and organic carbon（δ^（13）C_（org）） isotopes, as well as the concurrent positive shifts in sulfur isotopes of carbonate associated sulfate（CAS, δ^（34）S_（CAS）） and pyrite（δ^（34）S_（pyrite））, unequivocally indicating the presence of SPICE in the Jiangnan Basin. A 4‰ increase in δ^（13）C_（carb） of the Qingxi limestone implies the increase of the relative flux of organic carbon burial by a factor of two. Concurrent positive excursions in δ^（34）S_（CAS） and δ^（34）S_（pyrite） have been attributed to the enhanced pyrite burial in oceans with extremely low concentration and spatially heterogeneous isotopic composition of seawater sulfate. Here, we propose that the seawater sulfur isotopic heterogeneity can be generated by volatile organic sulfur compound（VOSC, such as methanethiol and dimethyl sulfide） formation in sulfidic continental margins that were widespread during SPICE. Emission of 32S-enriched VOSC in atmosphere, followed by lateral transportation and aerobic oxidation in atmosphere, and precipitation in open oceans result in a net flux of ^（32）S from continental margins to open oceans, elevating δ^（34）S of seawater sulfate in continental margins. A simple box model indicates that about 35% to 75% of seawater sulfate in continental margins needs to be transported to open oceans via VOSC formation.展开更多
Carbonate precipitation and hydrothermal reaction are the two major processes that remove Mg from seawater.Mg isotopes are significantly(up to 5%)fractionated during carbonate precipitation by preferential incorporati...Carbonate precipitation and hydrothermal reaction are the two major processes that remove Mg from seawater.Mg isotopes are significantly(up to 5%)fractionated during carbonate precipitation by preferential incorporation of ^(24)Mg,while hydrothermal reactions are associated with negligible Mg isotope fractionation by preferential sequestration of^( 26)Mg.Thus,the marine Mg cycle could be reflected by seawater Mg isotopic composition(δ^(26)Mg_(sw)),which might be recorded in marine carbonate.However,carbonates are both texturally and compositionally heterogeneous,and it is unclear which carbonate component is the most reliable for reconstructing δ^(26)Mg_(sw).In this study,we measured Mg isotopic compositions of limestone samples collected from the early Carboniferous Huangjin Formation in South China.Based on petrographic studies,four carbonate components were recognized:micrite,marine cement,brachiopod shell,and mixture.The four components had distinct δ^(26)Mg:(1)micrite samples ranged from -2.86% to -2.97%;(2)pure marine cements varied from -3.40% to -3.54%,while impure cement samples containing small amount of Rugosa coral skeletons showed a wider range(-3.27% to-3.75%);(3)values for the mixture component were-3.17% and -3.49%;and (4)brachiopod shells ranged from -2.20% to -3.07%,with the thickened hinge area enriched in ^( 24)Mg.Due to having multiple carbonate sources,neither the micrite nor the mixture component could be used to reconstruct δ^(26)Mg_(sw).In addition,the marine cement was homogenous in Mg isotopes,but lacking the fractionation by inorganic carbonate precipitation that is prerequisite for the accurate determination of δ^(26)Mg_(sw).Furthermore,brachiopod shells had heterogeneous C and Mg isotopes,suggesting a significant vital effect during growth.Overall,the heterogeneous δ^(26)Mg of the Huangjin limestone makes it difficult to reconstruct δ^(26)Mg_(sw)using bulk carbonate/calcareous sediments.Finally,δ^(26)Mg_(sw)was only slightly affected by the faunal composition of carbonate-secreting organisms,even though biogenic carbonate accounts for more than 90% of marine carbonate production in Phanerozoic oceans and there is a wide range(0.2%–4.8%)of fractionation during biogenic carbonate formation.展开更多
The continent is the second largest carbon sink on Earth’s surface.With the diversification of vascular land plants in the late Paleozoic,terrestrial organic carbon burial is represented by massive coal formation,whi...The continent is the second largest carbon sink on Earth’s surface.With the diversification of vascular land plants in the late Paleozoic,terrestrial organic carbon burial is represented by massive coal formation,while the development of soil profiles would account for both organic and inorganic carbon burial.As compared with soil organic carbon,inorganic carbon burial,collectively known as the soil carbonate,would have a greater impact on the long-term carbon cycle.Soil carbonate would have multiple carbon sources,including dissolution of host calcareous rocks,dissolved inorganic carbon from freshwater,and oxidation of organic matter,but the host calcareous rock dissolution would not cause atmospheric CO2drawdown.Thus,to evaluate the potential effect of soil carbonate formation on the atmospheric p CO2level,different carbon sources of soil carbonate should be quantitatively differentiated.In this study,we analyzed the carbon and magnesium isotopes of pedogenic calcite veins developed in a heavily weathered outcrop,consisting of limestone of the early Paleogene Guanzhuang Group in North China.Based on the C and Mg isotope data,we developed a numerical model to quantify the carbon source of calcite veins.The modeling results indicate that4–37 wt%of carbon in these calcite veins was derived from atmospheric CO2.The low contribution from atmospheric CO2might be attributed to the host limestone that might have diluted the atmospheric CO2sink.Nevertheless,taking this value into consideration,it is estimated that soil carbonate formation would lower 1 ppm atmospheric CO2within 2000 years,i.e.,soil carbonate alone would sequester all atmospheric CO2within 1 million years.Finally,our study suggests the C–Mg isotope system might be a better tool in quantifying the carbon source of soil carbonate.展开更多
It is a consensus that marine carbonate archives the isotopic composition of seawater dissolved inorganic carbon(DIC,δ13Csw),the largest active C reservoir in the hydrosphere.Carbonate carbon isotope(δ13Ccarb)excurs...It is a consensus that marine carbonate archives the isotopic composition of seawater dissolved inorganic carbon(DIC,δ13Csw),the largest active C reservoir in the hydrosphere.Carbonate carbon isotope(δ13Ccarb)excursions have been used to reflect perturbations of the global carbon cycle and related environmental change.However,the deep timeδ13Ccarb records indicate faster and more pronounced perturbations of the carbon cycle compared to the present day.Here,we reportδ13Ccarb and elemental compositions of Late Paleozoic carbonate sections from South China,showing negative correlations betweenδ13-Ccarb and Fe^(2+)content of carbonate(Fecarb).We suggest that,because Late Paleozoic carbonate was mainly produced by benthic carbonate-secreting organisms,δ13Ccarbrecorded the isotopic composition near the seafloor,where benthic flux derived from anaerobic organic matter degradation delivers both Fe2+and 13C-depleted DIC from porewater.The binary mixing between seawater and benthic flux would result in the deviation ofδ13Ccarb fromδ13Csw.The negative correlation implies thatδ13Ccarb is influenced by benthic flux and is affected by the seafloor redox and sedimentation rate.The deep time spatially heterogeneous and temporally oscillatoryδ13Ccarb records in the basin-scale could be alternatively attributed to the variations of local environmental factors rather than aδ13Csw depth-gradient.Thus,the seafloor carbonate precipitation is continuously affected by diagenetic reactions in sediments,suggesting thatδ13Ccarb recording the seawater DIC composition is conditional.Our study urges that the interpretation ofδ13Ccarb should also consider the sedimentary process and depositional environment of marine carbonate.展开更多
Phosphorite nodule beds are discovered in the black shale of basal Niutitang Formation throughout the Yangtze Platform in South China, recording an important phosphorite-generation event. Platform-wide phosphorite pre...Phosphorite nodule beds are discovered in the black shale of basal Niutitang Formation throughout the Yangtze Platform in South China, recording an important phosphorite-generation event. Platform-wide phosphorite precipitation requires special oceanographic and geochemical conditions, thus the origin of the Niutitang phosphorite nodules may provide valuable information about the ocean chemistry in the Early Cambrian. In this study, we measured sulfur and oxygen isotopic compositions of sulfate extracted from phosphorite nodules collected from the basal Niutitang Formation. Phosphorite associated sulfate（PAS） is a trace amount of sulfate that incorporates into crystal lattice during phosphorite precipitation, accordingly PAS records the geochemical signals during phosphorite nodule formation. Sulfur isotopic composition of PAS（δ^（34）S_（PAS）） ranges from-1.16‰ to ＋24.48‰（mean=＋8.19‰, n=11）, and oxygen isotopic value（δ^（18）O_（PAS）） varies between-5.3‰ and ＋26.3‰（mean=＋7.0‰, n=8）. Most phosphorite nodules have low δ^（34）SPAS and low δ^（18）O_（PAS） values, suggesting PAS mainly derived from anaerobic oxidation of H_2S within suboxic sediment porewater. We propose that phosphate was delivered to the Yangtze Platform by a series of upwelling events, and was scavenged from seawater with the precipitation of FeOOH. The absorbed phosphate was released into suboxic porewater by the reduction of FeOOH at the oxic-suboxic redox boundary in sediments, and phosphorite nodule precipitated by the reaction of phosphate with Ca^（2＋） diffused from the overlying seawater. The platform-wide deposition of phosphorite nodules in the basal Niutitang Formation implies the bottom water might be suboxic or even oxic, at least sporadically, in Early Cambrian. We speculate that the intensified ocean circulation as evident with frequent occurrences of upwelling events might be the primary reason for the episodic oxidation of the Yangtze Platform in Early Cambrian.展开更多
This work reports a superhydrophobic divinylbenzene polymer with hierarchical porous structure as sensing material to modify the quartz crystal microbalance(QCM)to detect benzene,toluene,ethylbenzene,and xylene(BTEX)v...This work reports a superhydrophobic divinylbenzene polymer with hierarchical porous structure as sensing material to modify the quartz crystal microbalance(QCM)to detect benzene,toluene,ethylbenzene,and xylene(BTEX)vapor.Notably,sensing results toward toluene vapor in different relative humidities indicates that this superhydrophobic polymer has favorable toluene/water selective detection performance.Besides,the limit of detection toward toluene is lower than 1 ppm.展开更多
Superconductivity has been realized in films of La_(1-x)Sr_(x)NiO_(2). Here we report synthesis and characterization of polycrystalline samples of La_(1-x)Sr_(x)NiO_(3) and La_(1-x) Sr_(x)NiO_(2)(0 ≤ x ≤ 0.2). Magne...Superconductivity has been realized in films of La_(1-x)Sr_(x)NiO_(2). Here we report synthesis and characterization of polycrystalline samples of La_(1-x)Sr_(x)NiO_(3) and La_(1-x) Sr_(x)NiO_(2)(0 ≤ x ≤ 0.2). Magnetization and resistivity measurements reveal that La_(1-x)Sr_(x)NiO_(3) are paramagnetic metal and La_(1-x)Sr_(x)NiO_(2) exhibit an insulating behavior. Superconductivity is not detected in bulk samples of La_(1-x)Sr_(x)NiO_(2). The absence of superconductivity in bulk La_(1-x)Sr_(x)NiO_(2) may be due to the generation of hydroxide during reduction, a small amount of nickel impurity, or incomplete reduction of apical oxygen.The effect of interface in films of La_(1-x)Sr_(x)NiO_(2) may also play a role for superconductivity.展开更多
Zeolitic imidazolate frameworks(ZIFs)are a series of materials composited by metal ions and organic ligands with high specific surface area,which might be great precursors to produce metal oxides by calcination for ga...Zeolitic imidazolate frameworks(ZIFs)are a series of materials composited by metal ions and organic ligands with high specific surface area,which might be great precursors to produce metal oxides by calcination for gas sensor application.However,Zn-ZIF(ZIF-8)is hard to transform as ZnO in air and keeping the unique framework simultaneously.In this work,Fe^(2+)was introduced into the metal node to replace a part of Zn^(2+)ions,and it could be oxidized as Fe^(3+)in the calcination to facilitate the oxidation process of the 2-methylimdazole ligands to give Fe-ZnO complex shell with high specific surface area(108 m~2/g)and abundant oxygen vacancies(48%).The micro electro mechanical systems(MEMS)sensor based on the6%-Fe-ZnO complex shell performed outstanding gas sensing properties to the low-concentration acetone vapor,including high response(ΔR/R_g=11.2 to 5 ppm acetone),superior selectivity(S_(acetone)/S_(ethanol)=5.6)and fast response speed(τ_(res)=2.6 s).This work not only provided the research of an exceptional acetone MEMS sensor,but also induced a strategy to produce metal oxide derived from ZIFs with complex structures for the universal synthesis methodology.展开更多
Bladder cancer is a common malignant tumor of the urinary system with the potential to be treated by nano drug delivery system.The current work describes the synthesis and characterization of a novel nanomaterial to c...Bladder cancer is a common malignant tumor of the urinary system with the potential to be treated by nano drug delivery system.The current work describes the synthesis and characterization of a novel nanomaterial to construct a nano-carrier based on 1-palmitoyl-2-oleoyl-sn-glycerol-3-phosphatecholine(POPC)loaded doxorubicin(DOX)and embedded with gold nanoparticles and poly(N-isopropyl acry-lamide)(PNIPAM)(GNPS@PNIPAM-POPC-DOX,GPPD).The dual-sensitive nanosystem gives simultaneous photothermal treatment and chemotherapy for bladder cancer.In vitro and in vivo properties were as-sessed using bladder cancer cell lines and mice and GPPD system distribution,tumor inhibition,and biocompatibility are reported.The system had favorable stability,low biological toxicity,controlled re-lease efficiency,photothermal synergistic action,efficient photothermal transition,and favorable tumor suppressive effects.As a result,GPPD is a potential therapeutic approach for bladder cancer.展开更多
The standard solar model proposes that the solar luminosity was 30%lower than the present level at 4.5 billion years ago(Ga).At low solar radiation,the climate model predicts that the Earth should have been completely...The standard solar model proposes that the solar luminosity was 30%lower than the present level at 4.5 billion years ago(Ga).At low solar radiation,the climate model predicts that the Earth should have been completely covered by ice in the first 2 billion years,i.e.in the snowball Earth climate mode,when the atmospheric CO2 content was at the present level.However,snowball Earth condition is inconsistent with various sedimentological,paleontological,and geochemical evidence.Such controversy is collectively known as the Taint Young Sun,(FYS)paradox.Though various models have been proposed,the FYS paradox has not yet been resolved.In this study,we develop a model by considering the ocean-atmosphere coupling to show that high atmospheric CO2 level could be sustained at low seawater pH.The modeling result indicates that 0.1 bar atmospheric CO2 level that was required to prevent snowball Earth in early Archean could be sustained at seawater pH of 6.8-7.2.Although the absence of siderite in Archean paleosols has been used to argue against high atmospheric CO2 level,we suggest that siderite precipitation in paleosols was not controlled by the atmospheric CO2 level alone.Instead,siderite could precipitate in anoxic conditions with various amount of CO2 in the atmosphere,suggesting siderite cannot be used to reconstruct the atmospheric CO2 level.Therefore,the new model suggests that the snowball Earth condition could be prevented by the coupling of atmosphere and ocean systems,and thus the emergence of the ocean in the very beginning of Earth evolution might be the key to the subsequence evolution of habitability.展开更多
We present an infrared spectroscopy study of the magnetic topological insulator MnBi_(4)Te_7 with antiferromagnetic(AFM) order below the Neel temperature TN= 13 K. Our investigation reveals that the low-frequency opti...We present an infrared spectroscopy study of the magnetic topological insulator MnBi_(4)Te_7 with antiferromagnetic(AFM) order below the Neel temperature TN= 13 K. Our investigation reveals that the low-frequency optical conductivity consists of two Drude peaks, indicating a response of free carriers involving multiple bands. Interestingly, the narrow Drude peak grows strongly as the temperature decreases, while the broad Drude peak remains relatively unchanged. The onset of interband transitions starts around 2000 cm^(-1), followed by two prominent absorption peaks around 10000 cm^(-1) and 20000 cm^(-1). Upon cooling, there is a notable transfer of spectral weight from the interband transitions to the Drude response. Below TN, the AFM transition gives rise to small anomalies of the charge response due to a band reconstruction.These findings provide valuable insights into the interplay between magnetism and the electronic properties in MnBi_(4)Te_7.展开更多
The kagome system has attracted great interest in condensed matter physics due to its unique structure that canhost various exotic states such as superconductivity(SC),charge density waves(CDWs)and nontrivial topologi...The kagome system has attracted great interest in condensed matter physics due to its unique structure that canhost various exotic states such as superconductivity(SC),charge density waves(CDWs)and nontrivial topological states.The topological semimetal RbTi_(3)Bi_(5)consisting of a Ti kagome layer shares a similar crystal structure to the topologicalcorrelated materials AV_(3)Sb_(5)(A=K,Rb,Cs)but without the absence of CDW and SC.Systematic de Haas-van Alphenoscillation measurements are performed on single crystals of RbTi_(3)Bi_(5)to pursue nontrivial topological physics and exoticstates.Combining this with theoretical calculations,the detailed Fermi surface topology and band structure are investigated.A two-dimensional Fermi pocket b is revealed with a light effective mass,consistent with the semimetal predictions.TheLandau fan diagram of RbTi_(3)Bi_(5)reveals a zero Berry phase for the b oscillation in contrast to that of CsTi_(3)Bi_(5).Theseresults suggest that kagome RbTi_(3)Bi_(5)is a good candidate for exploring nontrivial topological exotic states and topologicalcorrelated physics.展开更多
Temperature-driven change of Fermi surface has been attracting attention recently as it is fundamental and essential to understand a metallic system.We report the magnetotransport anomalies in the semimetal HfTe_(2) s...Temperature-driven change of Fermi surface has been attracting attention recently as it is fundamental and essential to understand a metallic system.We report the magnetotransport anomalies in the semimetal HfTe_(2) single crystals.The magnetoresistance behavior at high temperatures obeys Kohler's rule which can lead to the field-induced resistivity upturn behavior as observed.When the temperature is decreased to around 30 K,Kohler's rule becomes inapplicable,indicating the change of the Fermi surface in HfTe_(2).The Hall analyses and extended Kohler's plot reveal abrupt change of carrier densities and mobilities near 30 K.These results suggest that the chemical potential may shift as the temperature increases and the shift causes an electron pocket to vanish.Our work of the temperature-driven Lifshitz transition in HfTe_(2) is relevant to understanding of the transport anomalies and exotic physical properties in transition-metal dichalcogenides.展开更多
WTe2 has attracted a great deal of attention because it exhibits extremely large and non-saturating magnetore- sistance. The underlying origin of such a giant magnetoresistance is still under debate. Utilizing laser-b...WTe2 has attracted a great deal of attention because it exhibits extremely large and non-saturating magnetore- sistance. The underlying origin of such a giant magnetoresistance is still under debate. Utilizing laser-based angle-resolved photoemission spectroscopy with high energy and momentum resolutions, we reveal the complete electronic structure of WTe2. This makes it possible to determine accurately the electron and hole concentrations and their temperature dependence. We find that, with increasing the temperature, the overall electron concen- tration increases while the total hole concentration decreases. It indicates that the electron-hole compensation, if it exists, can only occur in a narrow temperature range,and in most of the temperature range there is an electron-hole imbalance. Our results are not consistent with the perfect electron-hole compensation picture that is commonly considered to be the cause of the unusual magnetoresistance in WTe2. We identify a fiat band near the Brillouin zone center that is close to the Fermi level and exhibits a pronounced temperature dependence. Such a fiat band can play an important role in dictating the transport properties of WTe2. Our results provide new insight on understanding the origin of the unusual magnetoresistance in WTe2.展开更多
基金supported by the National Natural Science Foundation of China(Nos.92059112,82072821 and 31470964)University of Shanghai for Science and Technology(No.10-21302-405)+1 种基金the Program of Shanghai Academic/Technology Research Leader(No.22XD1404700)the Shanghai Songjiang Municipal Science and Technology Commission Natural Science Foundation(No.20SJKJGG250)。
文摘The induction of antitumor immunity by tumor antigens released from cancer cells following regional photothermal therapy(PTT)alone may not be adequate for achieving complete tumor elimination.Combination therapy with immune adjuvants enhances antitumor immune responses,but faces challenges such as targeting deficiencies,systemic toxicity,and uncontrolled release behavior.Herein,we introduce a novel dual-functional hybrid membrane nanoparticle(HM-NP)incorporating gold nanorods(GNRs)and a thermally responsive polymer shell.HM-NP demonstrates exceptional homotypic targeting efficacy beneath the tumor cell membrane(TM),leading to substantial tumor accumulation.Upon in situ near-infrared(NIR)stimulation,GNRs within HM-NP generate heat,triggering the burst release of HM by facilitating the contraction and disintegration of the thermally responsive polymer shell.HM-NP exhibits excellent photothermal conversion efficiency under NIR irradiation,enabling effective destruction of primary tumors,release of tumor-associated antigens,and stimulation of potent anti-cancer immune.Simultaneously,the immune responses are strengthened by TM and Escherichia coli membrane(EM)through promoting the maturation of antigen presenting cells(APCs)and activating cytotoxic T lymphocytes(CTLs).Moreover,the use of polymer shells enables efficient cancer therapy with minimal host clearance and adverse effects.This photothermally triggered immunotherapy holds promise for precise and personalized treatment of tumors.
基金supported by Guangzhou Basic and Applied Basic Research Foundation(Grant No.2023B151520013)the National Natural Sciences Foundation of China(Grant No.92165204)+2 种基金the National Key Research and Development Program of China(Grant Nos.2023YFF0718400 and 2022YFA1403301)the Fund from the Research Center for Magnetoelectric Physics of Guangdong Province,China(Grant No.2024B0303390001)the Independent Fund of the State Key Laboratory of Optoelectronic&Materials and Technologies(Sun Yat-sen University)(Grant No.OEMT-2023-ZTS-01)。
文摘Kagome magnets Tb Mn_(6)Sn_(6-x)In_(x)(x=0-1.2)exhibit a robust anomalous Hall effect(AHE)that persists above room temperature,demonstrating significant potential for high-temperature spintronics applications.At elevated temperatures,a spin-reorientation transition induces a ferrimagnetic state(FIM1)with in-plane magnetic moments,accompanied by a nonmonotonic Hall response that differs markedly from the low-temperature behavior.Upon indium doping,the long-range ferrimagnetic transition is progressively suppressed to lower temperatures,along with a noticeable reduction in magnetic anisotropy.Interestingly,at a doping level of x=1.2,the FIM1 state observed in the parent compound is completely eliminated.These systematic changes in magnetic ordering and transport properties underscore a coherent evolution of the electronic and magnetic states with doping,offering critical insights into the interplay among lattice structure,magnetism,and electronic behavior in kagome lattices.
基金supported by the National Key Research and Development Program of China(Grant Nos.2022YFA1403800,2022YFA1403400,2021YFA1400400,2023YFA1406100,and 2024YFA1409200)the National Natural Science Foundation of China(Grant Nos.12274444,12374142,and 12304170)+1 种基金the Chinese Academy of Sciences President’s International Fellowship Initiative(Grant No.2025PG0007)We thank ISIS Facility for beam time(Grant No.RB2310088).
文摘The van der Waals cluster magnet Nb_(3)Cl_(8)has recently been shown to possibly host a quantum-spin-liquid ground state.The Nb ions in this compound form a breathing kagome structure,where the magnetic moment comes from three nearest Nb ions forming a molecular cluster with spin 1/2.Previous bulk measurements including magnetic susceptibility and specific heat suggested the existence of spinon Fermi surfaces.Here we further probe the spin system by nuclear magnetic resonance(NMR)and muon spin rotation and relaxation(μSR)techniques.We confirm that there is no magnetic long-range order and the dynamical spin fluctuations persist down to 0.075 K.These results provide further evidence that Nb_(3)Cl_(8)may host a quantum spin liquid.
基金supported by the National Natural science Foundation of China (Nos. 41203037, 41272017, 41472089, 41402025)the Chinese Geological Survey Program (Nos. 12120113015500, 12120114039701, 1212010633903, 1212011120622, J(2010)KP010705)+2 种基金Laboratory of Paleontology and Stratigraphy Open-lab grant (133103)the Science and Technology Foundation of Guizhou (No. QKHJZ(2012)2163)the Talents Introduction Foundation of Guizhou University (No. GDRJHZ(2011)17)
文摘The Terreneuvian Epoch（541-521 Ma）is also an important period for metallogenesis in South China, as was represented by the widespread occurrences of Ni-Mo polymetallic layers on the antecedent shallow platform margin and the V-enriched black shales in deeper slope-basin settings. In this study, we have measured Re-Os isochron ages of Ni-Mo polymetallic layers（Songlin, Niuchang, Sancha, Chuanpengwan）, V-rich black shales（Bahuang）, and non-metalliferous black shales（Shuidong） in the basal Niutitang Formation in Guizhou and Hunan province, South China. The Ni-Mo polymetallic layers and V-enriched black shales have similar Re-Os isochron ages, suggesting concurrent deposition of these two types of metalliferous ores. This suggestion is consistent with the traditional stratigraphic correlation by using the nodular phosphorite bed directly underlying these metalliferous layers as a stratigraphic marker. Furthermore, the metalliferous ores and non-metalliferous black shales have similar initial ^（187）Os/^（188） Os ratios of 0.8-0.9, arguing for a dominant seawater origin with minor contribution of hydrothermal activity. Furthermore, Re-Os isotopic data also imply that Ni-Mo and V ore might have derived from the same source. We suggest that the spatial distribution of metalliferous ores can be explained by the development of non-sulfidic anoxic-suboxic wedge（NSASW） in the slope-basin and sulfidic wedge in the previous platform margin. Upwelling of deep water first transects the mildly reduced, organic rich NSASW, in which V（V） is reduced to V（IV）, and is preferentially removed from seawater by organometallic complex formation. As a result, V-rich black shale deposits in the slope-basin of Yangtze Platform. Further movement of deep water into the sulfidic platform margin results in Ni-Mo polymetallic layer formation.
基金supported by National Science Foundation of China (Nos. 41172001 and 41772015 to Sun and No. 41772359 to Shen)
文摘Iron and manganese are the important redoxsensitive elements in the ocean. Previous studies have established a series of paleo-depositional redox proxies based on the form and content of iron in sedimentary rocks(e.g., degree of pyritization, FeHR/FeT, Fe/Al). These proxies were developed and applied on siliciclastic-rich marine sediments. Although marine carbonate rocks are generally considered to preserve the geochemical signals of ancient seawater, neither Fe nor Mn content in marine carbonate rocks(Fecarb, Mncarb) has been independently used as a proxy to quantify environmental cues in paleo-oceans. Both Fe and Mn are insoluble in oxic conditions(Fe_2O_3, Fe(OH)_3,MnO_2), while their reduced forms(Fe^(2+) and Mn^(2+)) are soluble. Therefore, oxic seawater should have low concentrations of dissolved Fe^(2+)and Mn^(2+), and accordingly carbonate rocks precipitated from oxic seawater should have low Fecarband Mncarb, and vice versa. To evaluate whether Fecarband Mncarbcan be used to quantify oxygen fugacity in seawater, we measured Fecarband Mncarbof Upper Devonian marine carbonate rocks collected from nine sections in South China. Fecarbof intraplatform basin samples wassignificantly higher than that of shelf samples, while shelf and basin samples had comparable Mncarb. The modeling result indicates that the dramatic difference in Fecarbcannot be explained by variation in oxygen fugacity between the shelf and basin seawater. Instead, both Fecarband Mncarb appear to be more sensitive to benthic flux from sediment porewater that is enriched in Fe^(2+)and Mn^(2+). Porewater Fe^(2+)and Mn^(2+)derive from bacterial iron and manganese reduction; flux was controlled by sedimentation rate and the depth of the Fe(Mn) reduction zone in sediments, the latter of which is determined by oxygen fugacity at the water–sediment interface. Thus, high Fecarbof the basin samples might be attributed to low sedimentation rate and/or low oxygen fugacity at the seafloor. However, invariant Mncarbof the shelf and basin samples might be the consequence of complete reduction of Mn in sediments. Our study indicates that marine carbonate rocks may not necessarily record seawater composition, particularly for benthic carbonate rocks. The influence of benthic flux might cause carbonate rocks' geochemical signals to deviate significantly from seawater values. Our study suggests that interpretation of geochemical data from carbonate rocks, including carbonate carbon isotopes, should consider the process of carbonate formation.
基金supported by the Natural Science Founddation of China (Nos.41272017,41322021)
文摘Global occurrences of Steptoean Positive Carbon Isotope Excursion（SPICE） during Late Cambrian recorded a significant perturbation in marine carbon cycle, and might have had profound impacts on the biological evolution. In previous studies, SPICE has been reported from the Jiangnan slope belt in South China. To evaluate the bathymetric extent of SPICE, we investigate the limestone samples from the upper Qingxi Formation in the Shaijiang Section in the Jiangnan Basin. Our results show the positive excursions for both carbonate carbon（δ^（13）C） and organic carbon（δ^（13）C_（org）） isotopes, as well as the concurrent positive shifts in sulfur isotopes of carbonate associated sulfate（CAS, δ^（34）S_（CAS）） and pyrite（δ^（34）S_（pyrite））, unequivocally indicating the presence of SPICE in the Jiangnan Basin. A 4‰ increase in δ^（13）C_（carb） of the Qingxi limestone implies the increase of the relative flux of organic carbon burial by a factor of two. Concurrent positive excursions in δ^（34）S_（CAS） and δ^（34）S_（pyrite） have been attributed to the enhanced pyrite burial in oceans with extremely low concentration and spatially heterogeneous isotopic composition of seawater sulfate. Here, we propose that the seawater sulfur isotopic heterogeneity can be generated by volatile organic sulfur compound（VOSC, such as methanethiol and dimethyl sulfide） formation in sulfidic continental margins that were widespread during SPICE. Emission of 32S-enriched VOSC in atmosphere, followed by lateral transportation and aerobic oxidation in atmosphere, and precipitation in open oceans result in a net flux of ^（32）S from continental margins to open oceans, elevating δ^（34）S of seawater sulfate in continental margins. A simple box model indicates that about 35% to 75% of seawater sulfate in continental margins needs to be transported to open oceans via VOSC formation.
基金supported by the Natural Science Foundation of China (41272017, 41322021, and 41172001)the China Postdoctoral Science Foundation (2014M55006)
文摘Carbonate precipitation and hydrothermal reaction are the two major processes that remove Mg from seawater.Mg isotopes are significantly(up to 5%)fractionated during carbonate precipitation by preferential incorporation of ^(24)Mg,while hydrothermal reactions are associated with negligible Mg isotope fractionation by preferential sequestration of^( 26)Mg.Thus,the marine Mg cycle could be reflected by seawater Mg isotopic composition(δ^(26)Mg_(sw)),which might be recorded in marine carbonate.However,carbonates are both texturally and compositionally heterogeneous,and it is unclear which carbonate component is the most reliable for reconstructing δ^(26)Mg_(sw).In this study,we measured Mg isotopic compositions of limestone samples collected from the early Carboniferous Huangjin Formation in South China.Based on petrographic studies,four carbonate components were recognized:micrite,marine cement,brachiopod shell,and mixture.The four components had distinct δ^(26)Mg:(1)micrite samples ranged from -2.86% to -2.97%;(2)pure marine cements varied from -3.40% to -3.54%,while impure cement samples containing small amount of Rugosa coral skeletons showed a wider range(-3.27% to-3.75%);(3)values for the mixture component were-3.17% and -3.49%;and (4)brachiopod shells ranged from -2.20% to -3.07%,with the thickened hinge area enriched in ^( 24)Mg.Due to having multiple carbonate sources,neither the micrite nor the mixture component could be used to reconstruct δ^(26)Mg_(sw).In addition,the marine cement was homogenous in Mg isotopes,but lacking the fractionation by inorganic carbonate precipitation that is prerequisite for the accurate determination of δ^(26)Mg_(sw).Furthermore,brachiopod shells had heterogeneous C and Mg isotopes,suggesting a significant vital effect during growth.Overall,the heterogeneous δ^(26)Mg of the Huangjin limestone makes it difficult to reconstruct δ^(26)Mg_(sw)using bulk carbonate/calcareous sediments.Finally,δ^(26)Mg_(sw)was only slightly affected by the faunal composition of carbonate-secreting organisms,even though biogenic carbonate accounts for more than 90% of marine carbonate production in Phanerozoic oceans and there is a wide range(0.2%–4.8%)of fractionation during biogenic carbonate formation.
基金funded by the National Key Technology Program during the 13th Five-Year Plan Period (Grant No. 2016ZX05034001-007)National Natural Science Foundation of China (Grant No. 41772359)
文摘The continent is the second largest carbon sink on Earth’s surface.With the diversification of vascular land plants in the late Paleozoic,terrestrial organic carbon burial is represented by massive coal formation,while the development of soil profiles would account for both organic and inorganic carbon burial.As compared with soil organic carbon,inorganic carbon burial,collectively known as the soil carbonate,would have a greater impact on the long-term carbon cycle.Soil carbonate would have multiple carbon sources,including dissolution of host calcareous rocks,dissolved inorganic carbon from freshwater,and oxidation of organic matter,but the host calcareous rock dissolution would not cause atmospheric CO2drawdown.Thus,to evaluate the potential effect of soil carbonate formation on the atmospheric p CO2level,different carbon sources of soil carbonate should be quantitatively differentiated.In this study,we analyzed the carbon and magnesium isotopes of pedogenic calcite veins developed in a heavily weathered outcrop,consisting of limestone of the early Paleogene Guanzhuang Group in North China.Based on the C and Mg isotope data,we developed a numerical model to quantify the carbon source of calcite veins.The modeling results indicate that4–37 wt%of carbon in these calcite veins was derived from atmospheric CO2.The low contribution from atmospheric CO2might be attributed to the host limestone that might have diluted the atmospheric CO2sink.Nevertheless,taking this value into consideration,it is estimated that soil carbonate formation would lower 1 ppm atmospheric CO2within 2000 years,i.e.,soil carbonate alone would sequester all atmospheric CO2within 1 million years.Finally,our study suggests the C–Mg isotope system might be a better tool in quantifying the carbon source of soil carbonate.
基金supported by the National Science Foundation of China(No.41772015 to Sun and No.41772359 to Shen)。
文摘It is a consensus that marine carbonate archives the isotopic composition of seawater dissolved inorganic carbon(DIC,δ13Csw),the largest active C reservoir in the hydrosphere.Carbonate carbon isotope(δ13Ccarb)excursions have been used to reflect perturbations of the global carbon cycle and related environmental change.However,the deep timeδ13Ccarb records indicate faster and more pronounced perturbations of the carbon cycle compared to the present day.Here,we reportδ13Ccarb and elemental compositions of Late Paleozoic carbonate sections from South China,showing negative correlations betweenδ13-Ccarb and Fe^(2+)content of carbonate(Fecarb).We suggest that,because Late Paleozoic carbonate was mainly produced by benthic carbonate-secreting organisms,δ13Ccarbrecorded the isotopic composition near the seafloor,where benthic flux derived from anaerobic organic matter degradation delivers both Fe2+and 13C-depleted DIC from porewater.The binary mixing between seawater and benthic flux would result in the deviation ofδ13Ccarb fromδ13Csw.The negative correlation implies thatδ13Ccarb is influenced by benthic flux and is affected by the seafloor redox and sedimentation rate.The deep time spatially heterogeneous and temporally oscillatoryδ13Ccarb records in the basin-scale could be alternatively attributed to the variations of local environmental factors rather than aδ13Csw depth-gradient.Thus,the seafloor carbonate precipitation is continuously affected by diagenetic reactions in sediments,suggesting thatδ13Ccarb recording the seawater DIC composition is conditional.Our study urges that the interpretation ofδ13Ccarb should also consider the sedimentary process and depositional environment of marine carbonate.
基金supported by the Natural Science Foundation of China (Nos. 41272017, 41322021)Chinese Geological Survey Program (No. 1212011120622)
文摘Phosphorite nodule beds are discovered in the black shale of basal Niutitang Formation throughout the Yangtze Platform in South China, recording an important phosphorite-generation event. Platform-wide phosphorite precipitation requires special oceanographic and geochemical conditions, thus the origin of the Niutitang phosphorite nodules may provide valuable information about the ocean chemistry in the Early Cambrian. In this study, we measured sulfur and oxygen isotopic compositions of sulfate extracted from phosphorite nodules collected from the basal Niutitang Formation. Phosphorite associated sulfate（PAS） is a trace amount of sulfate that incorporates into crystal lattice during phosphorite precipitation, accordingly PAS records the geochemical signals during phosphorite nodule formation. Sulfur isotopic composition of PAS（δ^（34）S_（PAS）） ranges from-1.16‰ to ＋24.48‰（mean=＋8.19‰, n=11）, and oxygen isotopic value（δ^（18）O_（PAS）） varies between-5.3‰ and ＋26.3‰（mean=＋7.0‰, n=8）. Most phosphorite nodules have low δ^（34）SPAS and low δ^（18）O_（PAS） values, suggesting PAS mainly derived from anaerobic oxidation of H_2S within suboxic sediment porewater. We propose that phosphate was delivered to the Yangtze Platform by a series of upwelling events, and was scavenged from seawater with the precipitation of FeOOH. The absorbed phosphate was released into suboxic porewater by the reduction of FeOOH at the oxic-suboxic redox boundary in sediments, and phosphorite nodule precipitated by the reaction of phosphate with Ca^（2＋） diffused from the overlying seawater. The platform-wide deposition of phosphorite nodules in the basal Niutitang Formation implies the bottom water might be suboxic or even oxic, at least sporadically, in Early Cambrian. We speculate that the intensified ocean circulation as evident with frequent occurrences of upwelling events might be the primary reason for the episodic oxidation of the Yangtze Platform in Early Cambrian.
基金supported by National Natural Science Foundation of China(No.61527818)the financial support from Zhejiang Sci-Tech University(ZSTU,No.19012393-Y)。
文摘This work reports a superhydrophobic divinylbenzene polymer with hierarchical porous structure as sensing material to modify the quartz crystal microbalance(QCM)to detect benzene,toluene,ethylbenzene,and xylene(BTEX)vapor.Notably,sensing results toward toluene vapor in different relative humidities indicates that this superhydrophobic polymer has favorable toluene/water selective detection performance.Besides,the limit of detection toward toluene is lower than 1 ppm.
基金supported by the National Natural Science Foundation of China (Grant Nos. 12174454, 11904414, 11904416, and U2130101)the Guangdong Basic and Applied Basic Research Foundation (Grant No. 2021B1515120015)+1 种基金the Guangzhou Basic and Applied Basic Research Foundation (Grant No. 202201011123)the National Key Research and Development Program of China (Grant No. 2019YFA0705702)。
文摘Superconductivity has been realized in films of La_(1-x)Sr_(x)NiO_(2). Here we report synthesis and characterization of polycrystalline samples of La_(1-x)Sr_(x)NiO_(3) and La_(1-x) Sr_(x)NiO_(2)(0 ≤ x ≤ 0.2). Magnetization and resistivity measurements reveal that La_(1-x)Sr_(x)NiO_(3) are paramagnetic metal and La_(1-x)Sr_(x)NiO_(2) exhibit an insulating behavior. Superconductivity is not detected in bulk samples of La_(1-x)Sr_(x)NiO_(2). The absence of superconductivity in bulk La_(1-x)Sr_(x)NiO_(2) may be due to the generation of hydroxide during reduction, a small amount of nickel impurity, or incomplete reduction of apical oxygen.The effect of interface in films of La_(1-x)Sr_(x)NiO_(2) may also play a role for superconductivity.
基金supported by the National Natural Science Foundation of China(No.62271299)Shanghai Engineering Research Center for Integrated Circuits and Advanced Display Materials。
文摘Zeolitic imidazolate frameworks(ZIFs)are a series of materials composited by metal ions and organic ligands with high specific surface area,which might be great precursors to produce metal oxides by calcination for gas sensor application.However,Zn-ZIF(ZIF-8)is hard to transform as ZnO in air and keeping the unique framework simultaneously.In this work,Fe^(2+)was introduced into the metal node to replace a part of Zn^(2+)ions,and it could be oxidized as Fe^(3+)in the calcination to facilitate the oxidation process of the 2-methylimdazole ligands to give Fe-ZnO complex shell with high specific surface area(108 m~2/g)and abundant oxygen vacancies(48%).The micro electro mechanical systems(MEMS)sensor based on the6%-Fe-ZnO complex shell performed outstanding gas sensing properties to the low-concentration acetone vapor,including high response(ΔR/R_g=11.2 to 5 ppm acetone),superior selectivity(S_(acetone)/S_(ethanol)=5.6)and fast response speed(τ_(res)=2.6 s).This work not only provided the research of an exceptional acetone MEMS sensor,but also induced a strategy to produce metal oxide derived from ZIFs with complex structures for the universal synthesis methodology.
基金funded by the National Natural Science Foundation of China(Nos.92059112,82072821,31470964)the Shanghai Songjiang Municipal Science and Technology Commission Natural Science Foundation(No.20SJKJGG250)+1 种基金University of Shanghai for Science and Technology(No.10–21–302–405)sponsored by the Program of Shanghai Academic Research Leader(No.22XD1404700)
文摘Bladder cancer is a common malignant tumor of the urinary system with the potential to be treated by nano drug delivery system.The current work describes the synthesis and characterization of a novel nanomaterial to construct a nano-carrier based on 1-palmitoyl-2-oleoyl-sn-glycerol-3-phosphatecholine(POPC)loaded doxorubicin(DOX)and embedded with gold nanoparticles and poly(N-isopropyl acry-lamide)(PNIPAM)(GNPS@PNIPAM-POPC-DOX,GPPD).The dual-sensitive nanosystem gives simultaneous photothermal treatment and chemotherapy for bladder cancer.In vitro and in vivo properties were as-sessed using bladder cancer cell lines and mice and GPPD system distribution,tumor inhibition,and biocompatibility are reported.The system had favorable stability,low biological toxicity,controlled re-lease efficiency,photothermal synergistic action,efficient photothermal transition,and favorable tumor suppressive effects.As a result,GPPD is a potential therapeutic approach for bladder cancer.
基金supported by the National Natural Science Foundation of China (Grant Number 41772359)
文摘The standard solar model proposes that the solar luminosity was 30%lower than the present level at 4.5 billion years ago(Ga).At low solar radiation,the climate model predicts that the Earth should have been completely covered by ice in the first 2 billion years,i.e.in the snowball Earth climate mode,when the atmospheric CO2 content was at the present level.However,snowball Earth condition is inconsistent with various sedimentological,paleontological,and geochemical evidence.Such controversy is collectively known as the Taint Young Sun,(FYS)paradox.Though various models have been proposed,the FYS paradox has not yet been resolved.In this study,we develop a model by considering the ocean-atmosphere coupling to show that high atmospheric CO2 level could be sustained at low seawater pH.The modeling result indicates that 0.1 bar atmospheric CO2 level that was required to prevent snowball Earth in early Archean could be sustained at seawater pH of 6.8-7.2.Although the absence of siderite in Archean paleosols has been used to argue against high atmospheric CO2 level,we suggest that siderite precipitation in paleosols was not controlled by the atmospheric CO2 level alone.Instead,siderite could precipitate in anoxic conditions with various amount of CO2 in the atmosphere,suggesting siderite cannot be used to reconstruct the atmospheric CO2 level.Therefore,the new model suggests that the snowball Earth condition could be prevented by the coupling of atmosphere and ocean systems,and thus the emergence of the ocean in the very beginning of Earth evolution might be the key to the subsequence evolution of habitability.
基金Project supported by the the National Natural Science Foundation of China (Grant No.12274442)the National Key R&D Program of China (Grant No.2022YFA1403901)。
文摘We present an infrared spectroscopy study of the magnetic topological insulator MnBi_(4)Te_7 with antiferromagnetic(AFM) order below the Neel temperature TN= 13 K. Our investigation reveals that the low-frequency optical conductivity consists of two Drude peaks, indicating a response of free carriers involving multiple bands. Interestingly, the narrow Drude peak grows strongly as the temperature decreases, while the broad Drude peak remains relatively unchanged. The onset of interband transitions starts around 2000 cm^(-1), followed by two prominent absorption peaks around 10000 cm^(-1) and 20000 cm^(-1). Upon cooling, there is a notable transfer of spectral weight from the interband transitions to the Drude response. Below TN, the AFM transition gives rise to small anomalies of the charge response due to a band reconstruction.These findings provide valuable insights into the interplay between magnetism and the electronic properties in MnBi_(4)Te_7.
基金supported by the National Key Research and Development Program of China(Grant No.2023YFA1406500)the National Natural Science Foundation of China(Grant Nos.12174454,U2130101,and 92165204)+2 种基金the Guangdong Basic and Applied Basic Research Funds(Grant Nos.2024B1515020040 and 2022A1515010035)Guangzhou Basic and Applied Basic Research Funds(Grant No.2024A04J6417)Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices(Grant No.2022B1212010008).
文摘The kagome system has attracted great interest in condensed matter physics due to its unique structure that canhost various exotic states such as superconductivity(SC),charge density waves(CDWs)and nontrivial topological states.The topological semimetal RbTi_(3)Bi_(5)consisting of a Ti kagome layer shares a similar crystal structure to the topologicalcorrelated materials AV_(3)Sb_(5)(A=K,Rb,Cs)but without the absence of CDW and SC.Systematic de Haas-van Alphenoscillation measurements are performed on single crystals of RbTi_(3)Bi_(5)to pursue nontrivial topological physics and exoticstates.Combining this with theoretical calculations,the detailed Fermi surface topology and band structure are investigated.A two-dimensional Fermi pocket b is revealed with a light effective mass,consistent with the semimetal predictions.TheLandau fan diagram of RbTi_(3)Bi_(5)reveals a zero Berry phase for the b oscillation in contrast to that of CsTi_(3)Bi_(5).Theseresults suggest that kagome RbTi_(3)Bi_(5)is a good candidate for exploring nontrivial topological exotic states and topologicalcorrelated physics.
基金the National Natural Science Foundation of China(Grant Nos.21BAA01133,12004441,92165204,11974431,11774434,and U2130101)the Natural Science Foundation of Guangdong Province of China(Grant No.2023A1515010487)+1 种基金the Guangzhou Basic and Applied Basic Research Foundation(Grant No.202201011109)the Fundamental Research Funds for the Central Universities(Grant No.22hytd07).
文摘Temperature-driven change of Fermi surface has been attracting attention recently as it is fundamental and essential to understand a metallic system.We report the magnetotransport anomalies in the semimetal HfTe_(2) single crystals.The magnetoresistance behavior at high temperatures obeys Kohler's rule which can lead to the field-induced resistivity upturn behavior as observed.When the temperature is decreased to around 30 K,Kohler's rule becomes inapplicable,indicating the change of the Fermi surface in HfTe_(2).The Hall analyses and extended Kohler's plot reveal abrupt change of carrier densities and mobilities near 30 K.These results suggest that the chemical potential may shift as the temperature increases and the shift causes an electron pocket to vanish.Our work of the temperature-driven Lifshitz transition in HfTe_(2) is relevant to understanding of the transport anomalies and exotic physical properties in transition-metal dichalcogenides.
基金Supported by the National Natural Science Foundation of China under Grant No 11574367the National Basic Research Program of China under Grant Nos 2013CB921904 and 2015CB921300+2 种基金the National Key Research and Development Program of China under Grant No 2016YFA0300600the Strategic Priority Research Program(B)of the Chinese Academy of Sciences under Grant No XDB07020300the US Department of Energy under Grant No DE-SC0014208
文摘WTe2 has attracted a great deal of attention because it exhibits extremely large and non-saturating magnetore- sistance. The underlying origin of such a giant magnetoresistance is still under debate. Utilizing laser-based angle-resolved photoemission spectroscopy with high energy and momentum resolutions, we reveal the complete electronic structure of WTe2. This makes it possible to determine accurately the electron and hole concentrations and their temperature dependence. We find that, with increasing the temperature, the overall electron concen- tration increases while the total hole concentration decreases. It indicates that the electron-hole compensation, if it exists, can only occur in a narrow temperature range,and in most of the temperature range there is an electron-hole imbalance. Our results are not consistent with the perfect electron-hole compensation picture that is commonly considered to be the cause of the unusual magnetoresistance in WTe2. We identify a fiat band near the Brillouin zone center that is close to the Fermi level and exhibits a pronounced temperature dependence. Such a fiat band can play an important role in dictating the transport properties of WTe2. Our results provide new insight on understanding the origin of the unusual magnetoresistance in WTe2.
