Artificially controlling the solid-state precipitation in aluminum (Al) alloys is an efficient way to achieve well-performed properties,and the microalloying strategy is the most frequently adopted method for such a p...Artificially controlling the solid-state precipitation in aluminum (Al) alloys is an efficient way to achieve well-performed properties,and the microalloying strategy is the most frequently adopted method for such a purpose.In this paper,recent advances in lengthscale-dependent scandium (Sc) microalloying effects in Al-Cu model alloys are reviewed.In coarse-grained Al-Cu alloys,the Sc-aided Cu/Sc/vacancies complexes that act as heterogeneous nuclei and Sc segregation at the θ′-Al_(2)Cu/matrix interface that reduces interfacial energy contribute significantly to θ′precipitation.By grain size refinement to the fine/ultrafine-grained scale,the strongly bonded Cu/Sc/vacancies complexes inhibit Cu and vacancy diffusing toward grain boundaries,promoting the desired intragranular θ′precipitation.At nanocrystalline scale,the applied high strain producing high-density vacancies results in the formation of a large quantity of (Cu Sc,vacancy)-rich atomic complexes with high thermal stability,outstandingly improving the strength/ductility synergy and preventing the intractable low-temperature precipitation.This review recommends the use of microalloying technology to modify the precipitation behaviors toward better combined mechanical properties and thermal stability in Al alloys.展开更多
{1012¯}twins were introduced into the magnesium(Mg)plate AZ31 via pre-rolling along its transverse direction.The plates,both with and without the pre-induced{1012¯}twins,were subjected to uniaxial tension al...{1012¯}twins were introduced into the magnesium(Mg)plate AZ31 via pre-rolling along its transverse direction.The plates,both with and without the pre-induced{1012¯}twins,were subjected to uniaxial tension along different directions.Using crystal plasticity modeling,we found that the strengthening effect of the pre-induced{1012¯}twins on the macroscopic flow stress primarily arised from the increased slip resistance caused by the boundaries,rather than the orientation hardening due to the twinning reorientation(although the latter did make its contribution in some specific loading directions).Besides,the pre-existing{1012¯}twins were found,by both experiments and simulation,to promote the activity of prismatic and pyramidal<c+a>in the parent matrix of the material.Further analysis showed that the enhanced non-basal slip activity is related to the{1012¯}twin boundaries’low micro Hall-Petch slope ratios of non-basal slips to basal slip.With the critical resolved shear stress(CRSS)obtained from crystal plasticity modeling and the orientation data from EBSD,a probability-based slip transfer model was proposed.The model predicts higher slip transfer probabilities and thus lower strain concentration tendencies at{1012¯}twin boundaries than that at grain boundaries,which agrees with the experimental observation that the strain localization was primarily associated with the latter.The present findings are helpful scientifically,in deepening our understanding of how the pre-induced{1012¯}twins affect the strength and slip activity of Mg alloys,and technologically,in guiding the design of the pre-strain protocol of Mg alloys.展开更多
Metallic thin films have attracted much attention owing to their unique mechanical properties,which are widely used in micro-/nano-devices.In this review,several key topics about the thin films in the micron to nano-s...Metallic thin films have attracted much attention owing to their unique mechanical properties,which are widely used in micro-/nano-devices.In this review,several key topics about the thin films in the micron to nano-scales are covered.First,the plastic deformation mechanisms in face-centered-cubic(FCC)metals,in particular the sizedependent deformation twinning at small scales,are discussed based on a deformation-mechanism map.Microstructural evolution is then briefly discussed from the perspective of the ratio of effective-to-internal stresses,while the stress-driven grain growth is discussed based on a twinning-mediated mechanism.The last section elucidates the size-dependent mechanical properties of metallic thin films,such as yield strength,ductility and mechanical fatigue behavior.展开更多
Designing microstructurally stable FeCrAl alloys with excellent strength-ductility synergy is highly desir-able for their engineering applications.However,due to the preference nucleation of precipitates at grain boun...Designing microstructurally stable FeCrAl alloys with excellent strength-ductility synergy is highly desir-able for their engineering applications.However,due to the preference nucleation of precipitates at grain boundaries(GBs),the improved precipitation strengthening of these alloys is usually accompanied by in-tergranular embrittlement.Here,we propose a novel thermomechanical processing route coupled with the Si alloying strategy via precipitation of coherent deformable Laves precipitates inside equiaxed fine-grains to achieve FeCrAl alloys with ultrahigh yield strength over∼992 MPa,excellent uniform elongation of∼7.6%at room temperature,and superior thermal stability at temperature∼1200℃.The Si alloying not only decreases the stacking fault energy of Laves precipitates favorable for their stacking-fault-mediated deformation but also hinders grain coarsening at 1200℃due to the Si-enrichment favorable for GB pin-ning effects.Our results prove the possibility of achieving the collaborative enhancement of mutually exclusive properties in alloys,such as strength-ductility-thermal stability via nanoprecipitation engineer-ing,and offer a promising route to prepare dispersion-strengthened materials.展开更多
The interaction between the gastric epithelium and immune cells plays key roles in H. pylori-associated pathology. Here, we demonstrate a procolonization and proinflammatory role of tubulointerstitial nephritis antige...The interaction between the gastric epithelium and immune cells plays key roles in H. pylori-associated pathology. Here, we demonstrate a procolonization and proinflammatory role of tubulointerstitial nephritis antigen-like 1 (TINAGL1), a newly discovered matricellular protein, in H. pylori infection. Increased TINAGL1 production by gastric epithelial cells (GECs) in the infected gastric mucosa was synergistically induced by H. pylori and IL-1β via the ERK-SP1 pathway in a cagA-dependent manner. Elevated human gastric TINAGL1 correlated with H. pylori colonization and the severity of gastritis, and mouse TINAGL1 derived from non-bone marrow-derived cells promoted bacterial colonization and inflammation. Importantly, H. pylori colonization and inflammation were attenuated in Tinagl1−/− and Tinagl1ΔGEC mice and were increased in mice injected with mouse TINAGL1. Mechanistically, TINAGL1 suppressed CCL21 expression and promoted CCL2 production in GECs by directly binding to integrin α5β1 to inhibit ERK and activate the NF-κB pathway, respectively, which not only led to decreased gastric influx of moDCs via CCL21-CCR7-dependent migration and, as a direct consequence, reduced the bacterial clearance capacity of the H. pylori-specific Th1 response, thereby promoting H. pylori colonization, but also resulted in increased gastric influx of Ly6Chigh monocytes via CCL2-CCR2-dependent migration. In turn, TINAGL1 induced the production of the proinflammatory protein S100A11 by Ly6Chigh monocytes, promoting H. pylori-associated gastritis. In summary, we identified a model in which TINAGL1 collectively ensures H. pylori persistence and promotes gastritis.展开更多
On September 5,2022,a strong MS6.8 earthquake struck the Luding area in the Kangding-Moxi segment of the Xianshuihe fault zone,which is the northern boundary of the Sichuan-Yunnan rhombic block,causing considerable ca...On September 5,2022,a strong MS6.8 earthquake struck the Luding area in the Kangding-Moxi segment of the Xianshuihe fault zone,which is the northern boundary of the Sichuan-Yunnan rhombic block,causing considerable casualties.The Bamei-Kangding segment of the Xianshuihe fault zone,which is located only tens of kilometers away from the Luding earthquake,has hosted frequent moderate to strong earthquakes in history and is a dangerous earthquake-prone zone.Therefore,it is critical to investigate the regional seismogenic environment for strong earthquakes and to evaluate the impact of the Luding earthquake in this area.For this purpose,we deployed a dense seismic array comprising over 200 short-period nodes in this region from July to August,2022 and acquired seismic ambient noise for over 30 days.Using the collected data,we conducted surface wave tomography and obtained a high-resolution 3-D shear wave velocity model for the regional shallow crust down to 8 km in depth.The key findings include:(1)the Bamei-Kangding segment of the Xianshuihe fault zone exhibits widespread stripped lowvelocity anomalies,suggesting shear movements at a relatively high temperature of the Xianshuihe fault zone;the Zheduoshan granitic pluton situated between the Zheduotang and southern Selaha faults shows a distinct low-velocity anomaly,which may be attributed to the localized high-temperature anomaly resulted by a deep magmatic heat source and the recent rapid uplift of the Zheduoshan area;(2)a ten-kilometer-wide high velocity body found below 4 km in depth near the Zhonggu area in the Bamei segment coincides with the seismic gap of moderate to strong earthquakes in this region,suggesting that the high velocity body may act as a seismic barrier;(3)the heterogeneity of the velocity structure along the Bamei-Kangding segment of the Xianshuihe fault zone corresponds to the regional changes in temperature,which reveals the reason for the spatially varying seismogenic potential in this segment;especially,the Selaha and Zheduotang faults which are located along the boundaries between the high and low velocity anomalies may possess considerable seismogenic potential;(4)the Coulomb failure stress calculations indicate that the Luding earthquake has imposed nontrivial stress loading in the Bamei-Kangding segment,and may shorten the earthquake recurrence intervals of the southern Selaha fault,the Zheduotang fault,and the Xuemenkan segment of the Xianshuihe fault zone.Thus,the Luding earthquake may potentially pose threats to the Sichuan-Xizang railway passing through this region.展开更多
Formal cross-dimerization of two different strained rings represents an innovative strategy toward specific ring systems that are otherwise inaccessible.Yet,formidable challenges remain in controlling the reactivity a...Formal cross-dimerization of two different strained rings represents an innovative strategy toward specific ring systems that are otherwise inaccessible.Yet,formidable challenges remain in controlling the reactivity and site-selectivity.Herein,we realized the reversal of site-selectivity in formal crossdimerization of benzocyclobutenones(BCBs)and silacyclobutanes(SCBs)by development of a nickel/magnesium synergistic catalytic system,in which the C(sp3)−C(carbonyl)bond of BCBs was exclusively cleaved,providing previously inaccessible eight-membered benzosilacycles.The catalytic cycle,the origin of this unconventional site-selectivity,and the role of MgCl2 have explicitly been elucidated by density functional theory calculations.Combined experimental and computational studies have clearly illustrated that the C1-C8 cleavage selectivity of BCBs in our reaction are mainly attributed to both the steric hindrance by introduction of substituents at the C3-and the proper choice of the Ni/Mg synergistic catalytic system.展开更多
Crustal-scale shear zones are believed to have played an important role in the tectonic and landscape evolution of orogens. However, the variation of long-term rock exhumation between the interior of shear zones and a...Crustal-scale shear zones are believed to have played an important role in the tectonic and landscape evolution of orogens. However, the variation of long-term rock exhumation between the interior of shear zones and adjacent regions has not been documented in detail. In this study, we obtained new zircon U-Pb, biotite ^(40)Ar/^(39)Ar, zircon and apatite(U-Th)/He data, and conducted inverse thermal history modeling from two age-elevation profiles(the Pianma and Tu'er profiles) in the southeastern Tibetan Plateau. Our goal is to constrain the exhumation history of the Gaoligong and Chongshan shear zones and adjacent regions, so as to explore the effect of the shear zones on exhumation and their thermal effect on cooling that should not be ignored. Our results suggest that during the interval of 18–11 Ma the exhumation rates of rocks within the Gaoligong shear zone are anomalously high compared with those outside of. The rapid cooling during 18–11 Ma appears to be restricted to the shear zone, likely due to localized thermal effects of shearing and exhumation. After 11 Ma, both the areas within and outside of the shear zones experienced a similar two-stage exhumation history: slower cooling until the early Pliocene, and then a rapid increase in cooling rate since the early Pliocene. Our results indicate a synchronized exhumation but with spatially varied exhumation rates. Our study also highlights the important role of large-scale shear zones in exposing rocks, and thus the importance of the structural context when interpreting thermochronological data in the southeastern margin of the Tibetan Plateau.展开更多
Sc solute clusters with a high number density were produced in an Al-0.3 wt.%Sc alloy when aged at250℃,while fine Al_(3)Sc precipitates were predominantly formed in the same alloy aged at 300℃.The alloy strengthened...Sc solute clusters with a high number density were produced in an Al-0.3 wt.%Sc alloy when aged at250℃,while fine Al_(3)Sc precipitates were predominantly formed in the same alloy aged at 300℃.The alloy strengthened by Sc solute clusters displayed higher yield strength and simultaneously greater ductility than its counterpart strengthened by Al_(3)Sc precipitates.This clearly demonstrates a superior strengthductility synergy promoted by the Sc solute clusters in Al-Sc alloys.The effects of Al_(3)Sc precipitates and Sc solute clusters on ductility were discussed in comparison by using a micromechanics fracture model.Since the Sc clusters were stabilized at 250℃,the Al-Sc alloys strengthened by Sc solute clusters should find extensive application fields within a wide temperature range,due to their high temperature resistance.展开更多
Metastable high entropy alloys(HEAs) and amorphous metallic glasses(MGs), with the chemical disordered character, are intensively studied due to their excellent performance. Here, we introduce Cu to separately constra...Metastable high entropy alloys(HEAs) and amorphous metallic glasses(MGs), with the chemical disordered character, are intensively studied due to their excellent performance. Here, we introduce Cu to separately constrain these two metastable materials and comparatively investigate their deformation behaviors and mechanical properties of Cu/HEA Fe Co Cr Ni and Cu/MG Cu Zr nanolaminated micropillars in terms of intrinsic layer thickness h and extrinsic pillar diameter D. The metastable HEA layers, as the hard phase in Cu/HEA micropillars, are stable and dominate the deformation, while transformation(crystallization) occurs in MG which plays a minor role in deformation of Cu/MG micropillars. The h-controlled deformation mode transits from the D-independent homogenous-like deformation at large h to the Ddependent shear banding at small h in both Cu/HEA and Cu/MG micropillars. Although both Cu/HEA and Cu/MG micropillars exhibit a maximum strain hardening capability controlled by h, the former manifests much lower hardening capability compared with the latter. The intrinsic size h and extrinsic size D have a strong coupling effect on the strength of Cu/HEA and Cu/MG micropillars. The strength of strength of Cu/HEA micropillars exhibits the D-dependent transition from "smaller is stronger" to "smaller is weaker"with increasing h. By contrast, the strength of Cu/MG micropillars exhibits the transition from bulk-like D-independent behavior at large h to small volume D-dependent behavior(smaller is stronger) at small h.展开更多
At present,many researchers have studied the modification of biochar and explored the adsorption of cadmium by modified biochar.The adsorption capacity of cadmium for general modified biochar is about 30-150 mg/g.The ...At present,many researchers have studied the modification of biochar and explored the adsorption of cadmium by modified biochar.The adsorption capacity of cadmium for general modified biochar is about 30-150 mg/g.The new biochar(BM)we studied greatly improves the adsorption effect of cadmium in water,and the maximum adsorption capacity of cadmium can reach 400 mg/g,so we tried to apply it to the passivated cadmium in polluted farmland soil.This paper discusses the mechanism of BM passivation of heavy metal cadmium in soil and its protective effect on crop growth.The study found that:(1)the content of cadmium in wheat was 3.98 mg/kg in the soil with BM800.The addition of BM800 reduced the cadmium content of wheat by 75.43%compared with the blank control group;(2)BM contains special iron-containing functional group(-Fe-OOC-,-Fe-R-COOH,-Fe-R-OH,etc.)and aromatic structure C=Cπ,and these structures can react with cadmium to form stable complexes(C=Cπ-Cd,(FeO)2Cd,(Fe-RO)2Cd,etc.);(3)there are special mineral crystal structures XiFeYjOk in BM.XiFeYjOk can react with cadmium to form Cd-XiFejOk.Cd-XiFejOk can stably exist in biochar,and can provide more adsorption sites,which strengthens the adsorption and passivation of cadmium in soil by BM.展开更多
Al-Mn-Fe-Si strips were fabricated via both the twin-roll casting(TRC)and the more conventional route,direct-chill casting(DC).The two types of strips prepared were subjected to thermal exposure at a series of tempera...Al-Mn-Fe-Si strips were fabricated via both the twin-roll casting(TRC)and the more conventional route,direct-chill casting(DC).The two types of strips prepared were subjected to thermal exposure at a series of temperatures.Uniaxial tensile tests after the thermal exposure showed that while the DC strip presented a~74%decrease in the yield strength and~35%decrease in the ultimate tensile strength(UTS)after being exposed to 350℃for 12 h,the TRC strip,in contrast,maintained its strength at temperatures up to~460℃ for the same duration.Systematic microstructure characterization revealed that the different thermal stability in the strength of the two types of strips arised from their distinct evolution in grain morphology and second phase particles during the thermal exposure.The calculation based on Cahn-Lücke-Stüwe(CLS)model suggested that due to the highly supersaturated solute atoms,at the beginning of the thermal exposure,the TRC strip experienced a strong solute drag which reduced the grain boundary migrating velocity to a value that is orders of magnitude smaller than that in the DC strip.With the progress of the thermal exposure,the solute atoms precipitated out,forming densely distributed second phase particles.For one thing,these particles stabilized the grain structure by inducing Zener pinning pressure which could be ten times higher than that in the DC strip,depending on the temperature.For another,they acted as dislocation obstacles and compensated for the strength loss owing to decreasing solution hardening.Both effects contributed to the TRC strip’s fairly stable strength regarding thermal exposure below 460°C.The present work could guide the direct application of the TRC strips in the industry.The results should also be helpful for the development of a fundamental framework for designing advanced TRC Al strips with improved mechanical properties at elevated temperatures.展开更多
Background: Ticks are hematophagous parasites that transmit an extensive range of pathogens to their vertebrate hosts.Ticks can destroy invading microorganisms or alleviate infection via their rudimentary but orchestr...Background: Ticks are hematophagous parasites that transmit an extensive range of pathogens to their vertebrate hosts.Ticks can destroy invading microorganisms or alleviate infection via their rudimentary but orchestrated innate immune system.Antimicrobial peptides(AMPs)are important components of tick innate immunity.Among these humoral effector molecules,defensins are well-studied and widely identified in various species of Ixodidae(hard ticks)and Argasidae(soft ticks).This review was aimed at presenting the characterization of tick defensins from structure-based taxonomic status to antimicrobial function.Main text: All published papers written in English from 2001 to May 2022 were searched through PubMed and Web of Science databases with the combination of relevant terms on tick defensins.Reports on identification and characterization of tick defensins were included.Of the 329 entries retrieved,57 articles were finally eligible for our scoping review.Tick defensins mainly belong to the antibacterial ancient invertebrate-type defensins of the cis-defensins superfamily.They are generally small,cationic,and amphipathic,with six cysteine residues forming three intra-molecular disulfide bonds.Tick defensins primarily target membranes of a variety of pathogens,including Gram-positive and Gram-negative bacteria,fungi,viruses,and protozoa.Since tick defensins have a high degree of variability,we summarize their common biological properties and enumerate representative peptides.Along with the various and potent antimicrobial activities,the role of tick defensins in determining vector competence is discussed.Conclusions: Due to their broad-spectrum antimicrobial activities,tick defensins are considered novel candidates or targets for controlling infectious diseases.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52201135,52271115,U23A6013,92360301,and U2330203)the 111 Project of China(No.BP2018008)+1 种基金the Shaanxi Province Innovation Team Project,China(No.2024RS-CXTD-58)supported by the International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technologies and by the open research fund of Suzhou Laboratory。
文摘Artificially controlling the solid-state precipitation in aluminum (Al) alloys is an efficient way to achieve well-performed properties,and the microalloying strategy is the most frequently adopted method for such a purpose.In this paper,recent advances in lengthscale-dependent scandium (Sc) microalloying effects in Al-Cu model alloys are reviewed.In coarse-grained Al-Cu alloys,the Sc-aided Cu/Sc/vacancies complexes that act as heterogeneous nuclei and Sc segregation at the θ′-Al_(2)Cu/matrix interface that reduces interfacial energy contribute significantly to θ′precipitation.By grain size refinement to the fine/ultrafine-grained scale,the strongly bonded Cu/Sc/vacancies complexes inhibit Cu and vacancy diffusing toward grain boundaries,promoting the desired intragranular θ′precipitation.At nanocrystalline scale,the applied high strain producing high-density vacancies results in the formation of a large quantity of (Cu Sc,vacancy)-rich atomic complexes with high thermal stability,outstandingly improving the strength/ductility synergy and preventing the intractable low-temperature precipitation.This review recommends the use of microalloying technology to modify the precipitation behaviors toward better combined mechanical properties and thermal stability in Al alloys.
基金supported by the National Natural Science Foundation of China(grant numbers 51801147,51790482,51722104,51625103,and 51621063)the National Key Re-search and Development Program of China(grant number 2017YFB0702301)the International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technologies.
文摘{1012¯}twins were introduced into the magnesium(Mg)plate AZ31 via pre-rolling along its transverse direction.The plates,both with and without the pre-induced{1012¯}twins,were subjected to uniaxial tension along different directions.Using crystal plasticity modeling,we found that the strengthening effect of the pre-induced{1012¯}twins on the macroscopic flow stress primarily arised from the increased slip resistance caused by the boundaries,rather than the orientation hardening due to the twinning reorientation(although the latter did make its contribution in some specific loading directions).Besides,the pre-existing{1012¯}twins were found,by both experiments and simulation,to promote the activity of prismatic and pyramidal<c+a>in the parent matrix of the material.Further analysis showed that the enhanced non-basal slip activity is related to the{1012¯}twin boundaries’low micro Hall-Petch slope ratios of non-basal slips to basal slip.With the critical resolved shear stress(CRSS)obtained from crystal plasticity modeling and the orientation data from EBSD,a probability-based slip transfer model was proposed.The model predicts higher slip transfer probabilities and thus lower strain concentration tendencies at{1012¯}twin boundaries than that at grain boundaries,which agrees with the experimental observation that the strain localization was primarily associated with the latter.The present findings are helpful scientifically,in deepening our understanding of how the pre-induced{1012¯}twins affect the strength and slip activity of Mg alloys,and technologically,in guiding the design of the pre-strain protocol of Mg alloys.
基金supported by the National Key Research and Development Program of China(2017YFA0700701,2017YFB0702301)the National Natural Science Foundation of China(Grant Nos.51621063,51722104,51625103,51790482,51761135031 and 51571157)+2 种基金the 111 Project 2.0 of China(BP2018008),the Fok Ying Tong Education Foundation(161096)the Shaanxi Province innovative talents promotion Projects(2018KJXX-004)the Fundamental Research Funds for the Central Universities.
文摘Metallic thin films have attracted much attention owing to their unique mechanical properties,which are widely used in micro-/nano-devices.In this review,several key topics about the thin films in the micron to nano-scales are covered.First,the plastic deformation mechanisms in face-centered-cubic(FCC)metals,in particular the sizedependent deformation twinning at small scales,are discussed based on a deformation-mechanism map.Microstructural evolution is then briefly discussed from the perspective of the ratio of effective-to-internal stresses,while the stress-driven grain growth is discussed based on a twinning-mediated mechanism.The last section elucidates the size-dependent mechanical properties of metallic thin films,such as yield strength,ductility and mechanical fatigue behavior.
基金supported by the National Natural Science Foundation of China(Grant Nos.92163201,52122103,U2067219)the Shaanxi Province Youth Innovation Team Project(No.22JP042)the Fundamental Research Funds for the Central Universities(No.xtr022019004).
文摘Designing microstructurally stable FeCrAl alloys with excellent strength-ductility synergy is highly desir-able for their engineering applications.However,due to the preference nucleation of precipitates at grain boundaries(GBs),the improved precipitation strengthening of these alloys is usually accompanied by in-tergranular embrittlement.Here,we propose a novel thermomechanical processing route coupled with the Si alloying strategy via precipitation of coherent deformable Laves precipitates inside equiaxed fine-grains to achieve FeCrAl alloys with ultrahigh yield strength over∼992 MPa,excellent uniform elongation of∼7.6%at room temperature,and superior thermal stability at temperature∼1200℃.The Si alloying not only decreases the stacking fault energy of Laves precipitates favorable for their stacking-fault-mediated deformation but also hinders grain coarsening at 1200℃due to the Si-enrichment favorable for GB pin-ning effects.Our results prove the possibility of achieving the collaborative enhancement of mutually exclusive properties in alloys,such as strength-ductility-thermal stability via nanoprecipitation engineer-ing,and offer a promising route to prepare dispersion-strengthened materials.
基金supported by grants from the National Natural Science Foundation of China(82070578,81870394,82000530 and 81670510)Chongqing Natural Science Fund for Distinguished Young Scholars(cstc2019jcyjjqX0003)+2 种基金Science Innovation Capacity Promotion Project of Army Medical University(2019XQY03)National Key Research and Development Program of China(2016YFC1302200)Collaborative Innovation Center of Chinese Ministry of Education(2020-39).
文摘The interaction between the gastric epithelium and immune cells plays key roles in H. pylori-associated pathology. Here, we demonstrate a procolonization and proinflammatory role of tubulointerstitial nephritis antigen-like 1 (TINAGL1), a newly discovered matricellular protein, in H. pylori infection. Increased TINAGL1 production by gastric epithelial cells (GECs) in the infected gastric mucosa was synergistically induced by H. pylori and IL-1β via the ERK-SP1 pathway in a cagA-dependent manner. Elevated human gastric TINAGL1 correlated with H. pylori colonization and the severity of gastritis, and mouse TINAGL1 derived from non-bone marrow-derived cells promoted bacterial colonization and inflammation. Importantly, H. pylori colonization and inflammation were attenuated in Tinagl1−/− and Tinagl1ΔGEC mice and were increased in mice injected with mouse TINAGL1. Mechanistically, TINAGL1 suppressed CCL21 expression and promoted CCL2 production in GECs by directly binding to integrin α5β1 to inhibit ERK and activate the NF-κB pathway, respectively, which not only led to decreased gastric influx of moDCs via CCL21-CCR7-dependent migration and, as a direct consequence, reduced the bacterial clearance capacity of the H. pylori-specific Th1 response, thereby promoting H. pylori colonization, but also resulted in increased gastric influx of Ly6Chigh monocytes via CCL2-CCR2-dependent migration. In turn, TINAGL1 induced the production of the proinflammatory protein S100A11 by Ly6Chigh monocytes, promoting H. pylori-associated gastritis. In summary, we identified a model in which TINAGL1 collectively ensures H. pylori persistence and promotes gastritis.
基金supported by the National Key Research and Development Project of China(Grant No.2021YFC3000602)the Special Fund of Key Laboratory of Earthquake Prediction,CEA(Grant No.2021IEF0103).
文摘On September 5,2022,a strong MS6.8 earthquake struck the Luding area in the Kangding-Moxi segment of the Xianshuihe fault zone,which is the northern boundary of the Sichuan-Yunnan rhombic block,causing considerable casualties.The Bamei-Kangding segment of the Xianshuihe fault zone,which is located only tens of kilometers away from the Luding earthquake,has hosted frequent moderate to strong earthquakes in history and is a dangerous earthquake-prone zone.Therefore,it is critical to investigate the regional seismogenic environment for strong earthquakes and to evaluate the impact of the Luding earthquake in this area.For this purpose,we deployed a dense seismic array comprising over 200 short-period nodes in this region from July to August,2022 and acquired seismic ambient noise for over 30 days.Using the collected data,we conducted surface wave tomography and obtained a high-resolution 3-D shear wave velocity model for the regional shallow crust down to 8 km in depth.The key findings include:(1)the Bamei-Kangding segment of the Xianshuihe fault zone exhibits widespread stripped lowvelocity anomalies,suggesting shear movements at a relatively high temperature of the Xianshuihe fault zone;the Zheduoshan granitic pluton situated between the Zheduotang and southern Selaha faults shows a distinct low-velocity anomaly,which may be attributed to the localized high-temperature anomaly resulted by a deep magmatic heat source and the recent rapid uplift of the Zheduoshan area;(2)a ten-kilometer-wide high velocity body found below 4 km in depth near the Zhonggu area in the Bamei segment coincides with the seismic gap of moderate to strong earthquakes in this region,suggesting that the high velocity body may act as a seismic barrier;(3)the heterogeneity of the velocity structure along the Bamei-Kangding segment of the Xianshuihe fault zone corresponds to the regional changes in temperature,which reveals the reason for the spatially varying seismogenic potential in this segment;especially,the Selaha and Zheduotang faults which are located along the boundaries between the high and low velocity anomalies may possess considerable seismogenic potential;(4)the Coulomb failure stress calculations indicate that the Luding earthquake has imposed nontrivial stress loading in the Bamei-Kangding segment,and may shorten the earthquake recurrence intervals of the southern Selaha fault,the Zheduotang fault,and the Xuemenkan segment of the Xianshuihe fault zone.Thus,the Luding earthquake may potentially pose threats to the Sichuan-Xizang railway passing through this region.
基金supported by the National Natural Science Foundation of China(U2067219,92163201,52001247)the Initiative Postdocs Supporting Program(BX20190266)+1 种基金Shaanxi Province Youth Innovation Team Project(22JP042)the Fundamental Research Funds for the Central Universities(xtr022019004,xzy022019071)。
基金grateful for financial support from the National Natural Science Foundation of China(grant nos.22071114,22022103,21871146,22122104,22193012,22188101,and 21933004)the National Key Research and Development Program of China(grant nos.2019YFA0210500 and 2021YFF0701700)+1 种基金the Frontiers Science Center for New Organic Matter,Nankai University(grant no.63181206)the Fundamental Research Funds for the Central Universities and Nankai University.
文摘Formal cross-dimerization of two different strained rings represents an innovative strategy toward specific ring systems that are otherwise inaccessible.Yet,formidable challenges remain in controlling the reactivity and site-selectivity.Herein,we realized the reversal of site-selectivity in formal crossdimerization of benzocyclobutenones(BCBs)and silacyclobutanes(SCBs)by development of a nickel/magnesium synergistic catalytic system,in which the C(sp3)−C(carbonyl)bond of BCBs was exclusively cleaved,providing previously inaccessible eight-membered benzosilacycles.The catalytic cycle,the origin of this unconventional site-selectivity,and the role of MgCl2 have explicitly been elucidated by density functional theory calculations.Combined experimental and computational studies have clearly illustrated that the C1-C8 cleavage selectivity of BCBs in our reaction are mainly attributed to both the steric hindrance by introduction of substituents at the C3-and the proper choice of the Ni/Mg synergistic catalytic system.
基金supported by the National Natural Science Foundation of China(Grant Nos.41761144065,41902213 and 41702223)the State Key Laboratory of Earthquake Dynamics of China(Grant No.LED2016A02)+1 种基金the National Key Research and Development Project of China(Grant No.2016YFC0600310)the Natural Environment Research Council of UK(Grant No.NE/N015479/1)。
文摘Crustal-scale shear zones are believed to have played an important role in the tectonic and landscape evolution of orogens. However, the variation of long-term rock exhumation between the interior of shear zones and adjacent regions has not been documented in detail. In this study, we obtained new zircon U-Pb, biotite ^(40)Ar/^(39)Ar, zircon and apatite(U-Th)/He data, and conducted inverse thermal history modeling from two age-elevation profiles(the Pianma and Tu'er profiles) in the southeastern Tibetan Plateau. Our goal is to constrain the exhumation history of the Gaoligong and Chongshan shear zones and adjacent regions, so as to explore the effect of the shear zones on exhumation and their thermal effect on cooling that should not be ignored. Our results suggest that during the interval of 18–11 Ma the exhumation rates of rocks within the Gaoligong shear zone are anomalously high compared with those outside of. The rapid cooling during 18–11 Ma appears to be restricted to the shear zone, likely due to localized thermal effects of shearing and exhumation. After 11 Ma, both the areas within and outside of the shear zones experienced a similar two-stage exhumation history: slower cooling until the early Pliocene, and then a rapid increase in cooling rate since the early Pliocene. Our results indicate a synchronized exhumation but with spatially varied exhumation rates. Our study also highlights the important role of large-scale shear zones in exposing rocks, and thus the importance of the structural context when interpreting thermochronological data in the southeastern margin of the Tibetan Plateau.
基金supported by the National Natural Science Foundation of China (51621063, 51722104, 51625103, 51790482, 51761135031 and 51571157)the National Key Research and Development Program of China (2017YFA0700701 and 2017YFB0702301)+6 种基金the 111 Project 2.0 of China (BP2018008)the International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technologiesthe Fundamental Research Funds for the Central Universities (xzy022019071)the Fok Ying-Tong Education Foundation (161096)China Postdoctoral Science Foundation (2017T100744)Shaanxi Province innovative talents promotion Projects (2018KJXX-004)the support from China Postdoctoral Science Foundation (2016M602811)
基金financially supported by the National Natural Science Foundation of China(Nos.52071253,51621063,51625103,51722104 and 51790482)the“111 Project”of China(BP2018008)the Financial support by the International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technologies。
文摘Sc solute clusters with a high number density were produced in an Al-0.3 wt.%Sc alloy when aged at250℃,while fine Al_(3)Sc precipitates were predominantly formed in the same alloy aged at 300℃.The alloy strengthened by Sc solute clusters displayed higher yield strength and simultaneously greater ductility than its counterpart strengthened by Al_(3)Sc precipitates.This clearly demonstrates a superior strengthductility synergy promoted by the Sc solute clusters in Al-Sc alloys.The effects of Al_(3)Sc precipitates and Sc solute clusters on ductility were discussed in comparison by using a micromechanics fracture model.Since the Sc clusters were stabilized at 250℃,the Al-Sc alloys strengthened by Sc solute clusters should find extensive application fields within a wide temperature range,due to their high temperature resistance.
基金supported by the National Natural Science Foundation of China (Grant Nos.51722104,51625103,51790482,and 51761135031)the National Key Research and Development Program of China (2017YFA0700701)+3 种基金the 111 Project 2.0 of China(BP2018008)the Fok Ying-Tong Education Foundation (161096)the Fundamental Research Funds for the Central Universitiessupported by the Fundamental Research Funds for the Central Universities (xzy022019071)。
文摘Metastable high entropy alloys(HEAs) and amorphous metallic glasses(MGs), with the chemical disordered character, are intensively studied due to their excellent performance. Here, we introduce Cu to separately constrain these two metastable materials and comparatively investigate their deformation behaviors and mechanical properties of Cu/HEA Fe Co Cr Ni and Cu/MG Cu Zr nanolaminated micropillars in terms of intrinsic layer thickness h and extrinsic pillar diameter D. The metastable HEA layers, as the hard phase in Cu/HEA micropillars, are stable and dominate the deformation, while transformation(crystallization) occurs in MG which plays a minor role in deformation of Cu/MG micropillars. The h-controlled deformation mode transits from the D-independent homogenous-like deformation at large h to the Ddependent shear banding at small h in both Cu/HEA and Cu/MG micropillars. Although both Cu/HEA and Cu/MG micropillars exhibit a maximum strain hardening capability controlled by h, the former manifests much lower hardening capability compared with the latter. The intrinsic size h and extrinsic size D have a strong coupling effect on the strength of Cu/HEA and Cu/MG micropillars. The strength of strength of Cu/HEA micropillars exhibits the D-dependent transition from "smaller is stronger" to "smaller is weaker"with increasing h. By contrast, the strength of Cu/MG micropillars exhibits the transition from bulk-like D-independent behavior at large h to small volume D-dependent behavior(smaller is stronger) at small h.
基金the Priority Academic Program Development of Jiangsu Higher Education InstitutionsProgram for Changjiang Scholars and Innovative Research Team in University(PCSIRT)+4 种基金the National Natural Science Foundation of China(31770933 and 81971917)the Natural Science Foundation of Colleges in Jiangsu Province(17KJA310005)the Open Project Fund from State Key Laboratory of Genetic Engineering,Fudan University(SKLGE1903)the Key Laboratory of Reproduction Regulation of NHC(KF2018-01)a grant from Soochow Securities。
基金supported by the National Natural Science Foundation of China(no.41571283)the National Key Research and Development Program of China(2018YFD0800703,2016YFD0800702)the Fundamental Research Funds for the Central Universities(2662018PY078)。
文摘At present,many researchers have studied the modification of biochar and explored the adsorption of cadmium by modified biochar.The adsorption capacity of cadmium for general modified biochar is about 30-150 mg/g.The new biochar(BM)we studied greatly improves the adsorption effect of cadmium in water,and the maximum adsorption capacity of cadmium can reach 400 mg/g,so we tried to apply it to the passivated cadmium in polluted farmland soil.This paper discusses the mechanism of BM passivation of heavy metal cadmium in soil and its protective effect on crop growth.The study found that:(1)the content of cadmium in wheat was 3.98 mg/kg in the soil with BM800.The addition of BM800 reduced the cadmium content of wheat by 75.43%compared with the blank control group;(2)BM contains special iron-containing functional group(-Fe-OOC-,-Fe-R-COOH,-Fe-R-OH,etc.)and aromatic structure C=Cπ,and these structures can react with cadmium to form stable complexes(C=Cπ-Cd,(FeO)2Cd,(Fe-RO)2Cd,etc.);(3)there are special mineral crystal structures XiFeYjOk in BM.XiFeYjOk can react with cadmium to form Cd-XiFejOk.Cd-XiFejOk can stably exist in biochar,and can provide more adsorption sites,which strengthens the adsorption and passivation of cadmium in soil by BM.
基金supported by the National Natural Science Foundation of China(Nos.51790482,51801147,51722104,51625103,and 51621063)the National Key Research and Development Program of China(No.2017YFB0702301)supported by the International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technologies。
文摘Al-Mn-Fe-Si strips were fabricated via both the twin-roll casting(TRC)and the more conventional route,direct-chill casting(DC).The two types of strips prepared were subjected to thermal exposure at a series of temperatures.Uniaxial tensile tests after the thermal exposure showed that while the DC strip presented a~74%decrease in the yield strength and~35%decrease in the ultimate tensile strength(UTS)after being exposed to 350℃for 12 h,the TRC strip,in contrast,maintained its strength at temperatures up to~460℃ for the same duration.Systematic microstructure characterization revealed that the different thermal stability in the strength of the two types of strips arised from their distinct evolution in grain morphology and second phase particles during the thermal exposure.The calculation based on Cahn-Lücke-Stüwe(CLS)model suggested that due to the highly supersaturated solute atoms,at the beginning of the thermal exposure,the TRC strip experienced a strong solute drag which reduced the grain boundary migrating velocity to a value that is orders of magnitude smaller than that in the DC strip.With the progress of the thermal exposure,the solute atoms precipitated out,forming densely distributed second phase particles.For one thing,these particles stabilized the grain structure by inducing Zener pinning pressure which could be ten times higher than that in the DC strip,depending on the temperature.For another,they acted as dislocation obstacles and compensated for the strength loss owing to decreasing solution hardening.Both effects contributed to the TRC strip’s fairly stable strength regarding thermal exposure below 460°C.The present work could guide the direct application of the TRC strips in the industry.The results should also be helpful for the development of a fundamental framework for designing advanced TRC Al strips with improved mechanical properties at elevated temperatures.
基金This work was supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions,National Natural Science Foundation of China(81971917,32170142 and 81271792)Jiangsu Natural Science Foundation(BK20211310)+2 种基金Open Project Fund from State Key Laboratory of Genetic Engineering,Fudan University(SKLGE1903)the Jiangsu Undergraduate Training Program for Innovation and Entrepreneurship,Soochow University(202010285133Y)the 23rd Undergraduates Extracurricular Academic Research Fund,Soochow University(KY20210120A).
文摘Background: Ticks are hematophagous parasites that transmit an extensive range of pathogens to their vertebrate hosts.Ticks can destroy invading microorganisms or alleviate infection via their rudimentary but orchestrated innate immune system.Antimicrobial peptides(AMPs)are important components of tick innate immunity.Among these humoral effector molecules,defensins are well-studied and widely identified in various species of Ixodidae(hard ticks)and Argasidae(soft ticks).This review was aimed at presenting the characterization of tick defensins from structure-based taxonomic status to antimicrobial function.Main text: All published papers written in English from 2001 to May 2022 were searched through PubMed and Web of Science databases with the combination of relevant terms on tick defensins.Reports on identification and characterization of tick defensins were included.Of the 329 entries retrieved,57 articles were finally eligible for our scoping review.Tick defensins mainly belong to the antibacterial ancient invertebrate-type defensins of the cis-defensins superfamily.They are generally small,cationic,and amphipathic,with six cysteine residues forming three intra-molecular disulfide bonds.Tick defensins primarily target membranes of a variety of pathogens,including Gram-positive and Gram-negative bacteria,fungi,viruses,and protozoa.Since tick defensins have a high degree of variability,we summarize their common biological properties and enumerate representative peptides.Along with the various and potent antimicrobial activities,the role of tick defensins in determining vector competence is discussed.Conclusions: Due to their broad-spectrum antimicrobial activities,tick defensins are considered novel candidates or targets for controlling infectious diseases.
