Reservoir-induced landslides in China's Three Gorges Reservoir area are prone to tensile cracks due to the influenceof their own weight and fluctuationsin water levels.The presence of cracks indicates that the ten...Reservoir-induced landslides in China's Three Gorges Reservoir area are prone to tensile cracks due to the influenceof their own weight and fluctuationsin water levels.The presence of cracks indicates that the tensile stress in the area has exceeded the tensile strength of the soil,leading to local instability.To explore the impact of tensile failure behavior on the stability and failure modes of reservoir landslides,the Huangtupo Riverside Slump#1 is taken as a case study.By considering local tensile failure,potential tensile cracks are incorporated into the analysis via the limit equilibrium method and reliability theory.The reliability of landslides under different tensile failure scenarios is quantified.Strain-softening characteristics of the soil are combined to further analyze the failure transmission path of the landslide.Finally,these potential failure modes were validated through physical model tests.The results show that cracks developing at rear positions reduce the stability of the slope and increase the probability of instability.During the destruction process,retrogressive failures with multiple sliding surfaces are likely to occur.However,tensile failure at the forefront reduces the likelihood of an individual slide mass descending.Progressive failure results in both regular and skip transmission patterns.Additionally,cracks and water level changes can also lead to shifts in the positions of the most dangerous blocks.Therefore,in practical landslide analysis and prevention,it is necessary to consider local tensile damage and identify potential tensile crack locations in advance to optimize prevention measures and accurately evaluate landslide risk.展开更多
Wide-temperature applications of sodium-ion batteries(SIBs)are severely limited by the sluggish ion insertion/diffusion kinetics of conversion-type anodes.Quantum-sized transition metal dichalcogenides possess unique ...Wide-temperature applications of sodium-ion batteries(SIBs)are severely limited by the sluggish ion insertion/diffusion kinetics of conversion-type anodes.Quantum-sized transition metal dichalcogenides possess unique advantages of charge delocalization and enrich uncoordinated electrons and short-range transfer kinetics,which are crucial to achieve rapid low-temperature charge transfer and high-temperature interface stability.Herein,a quantum-scale FeS_(2) loaded on three-dimensional Ti_(3)C_(2) MXene skeletons(FeS_(2) QD/MXene)fabricated as SIBs anode,demonstrating impressive performance under wide-temperature conditions(−35 to 65).The theoretical calculations combined with experimental characterization interprets that the unsaturated coordination edges of FeS_(2) QD can induce delocalized electronic regions,which reduces electrostatic potential and significantly facilitates efficient Na+diffusion across a broad temperature range.Moreover,the Ti_(3)C_(2) skeleton reinforces structural integrity via Fe-O-Ti bonding,while enabling excellent dispersion of FeS_(2) QD.As expected,FeS_(2) QD/MXene anode harvests capacities of 255.2 and 424.9 mAh g^(−1) at 0.1 A g^(−1) under−35 and 65,and the energy density of FeS_(2) QD/MXene//NVP full cell can reach to 162.4 Wh kg^(−1) at−35,highlighting its practical potential for wide-temperatures conditions.This work extends the uncoordinated regions induced by quantum-size effects for exceptional Na^(+)ion storage and diffusion performance at wide-temperatures environment.展开更多
An integrated petrographical and geochemical study of the massive dolomite of the lower Ordovician Penglaiba Formation of the Tarim Basin,outcropping at Yonganba recognized three dolomite types:very finely to finely c...An integrated petrographical and geochemical study of the massive dolomite of the lower Ordovician Penglaiba Formation of the Tarim Basin,outcropping at Yonganba recognized three dolomite types:very finely to finely crystalline nonplanar-a to planar-s dolomite(D1);medium crystalline planar-s to planar-e dolomite(D2);and coarse crystalline nonplanar-a dolomite(D3).All have been affected by burial.D1 and D2 dolomites developed initially before or during shallow burial and later recrystallized,whereas D3 dolomite replaced the initial limestone entirely during burial.All three dolomites have similar geochemical features.The D2 dolomite tends to have more inter-crystalline pores(inherited from primary pores)and higher porosity due to its outstanding compaction resistance during shallow burial;whereas D3 dolomite does not retain appreciable primary pores due to strong cementation and pressure dissolution before dolomitization.This study provides a useful model for understanding the origin and porosity development of burial dolomite,in particular Paleozoic dolomite.展开更多
Post-traumatic stress disorder(PTSD)is a severe neuropsychiatric disorder characterised by reexperiencing,avoidance and hyperarousal.Memory abnormalities manifested as intrusive thoughts and prolonged distressful emot...Post-traumatic stress disorder(PTSD)is a severe neuropsychiatric disorder characterised by reexperiencing,avoidance and hyperarousal.Memory abnormalities manifested as intrusive thoughts and prolonged distressful emotions are postulated as key roles in PTSD development and persistence.Over the past decades,convergent results from human and animal studies have systematically investigated contributions of the amygdala,hippocampus and medial prefrontal cortex(mPFC)in fear memory processes,including fear acquisition,storage,reconsolidation and extinction.These findings provide mechanistic insights for cognitive-behavioural therapy and aid in developing pathological region-targeted neuromodulation treatment for PTSD.Taking advantage of advances in cell-type selective labelling and manipulation technologies,recent studies have focused on the spatiotemporal regulation of neural circuits underlying distinct phases of fear memory processes.These findings have revealed that multiple distributed brain areas participate in the fear memory encoding network.Moreover,the functional role of distinct neuronal ensembles within the amygdala-hippocampus-mPFC pathway,identified by genetic markers and projection profiles,has been assigned to temporally separate features of fear processing,demonstrating the sophistication of the fear encoding circuit.These results provide mechanistic insights into PTSD pathology and might shed light on aetiology-based clinical interventions for PTSD.Therefore,the present review will mainly focus on the recent progress in elucidating neural circuit mechanisms underlying the dynamic regulation of fear memory,with an emphasis on the spatial distribution of fear memory encoding neural networks and the temporal coherence between neuronal ensemble activity and fear expression.展开更多
In 2018,Baige,Xizang,witnessed two consecutive large-scale landslides,causing significant damage and drawing widespread attention.From March 2011 to February 2018,the Baige landslide exhibited a 50-m displacement with...In 2018,Baige,Xizang,witnessed two consecutive large-scale landslides,causing significant damage and drawing widespread attention.From March 2011 to February 2018,the Baige landslide exhibited a 50-m displacement without complete failure,culminating in a collapse in October 2018.The mechanisms behind its resistance to failure despite substantial deformation and the influence of the complex geo-structure within the tectonic mélange belt remain unclear.To address these questions,this study utilized a multidisciplinary approach,integrating on-site geological field mapping,surface deformation monitoring,multielectrode resistivity method,and deep displacement analysis.The aim was to evaluate the impact of the intricate geo-structure within the tectonic mélange belt on the Baige landslide events.Findings reveal that the landslide's geo-structure consists of structurally fractured,mesh-like rock masses,including heterogeneous lenticular rock masses and intermittent brittle shear zones distributed around the lens-shaped rock masses.The study underscores that the inhomogeneous and weakly deformed lenticular rock masses function as natural locked segments,governing the stability of the Baige landslide.Specifically,the relatively intact and hard granodiorite porphyry play a crucial role in locking the landslide's deformation.Deep displacement analysis indicates that the brittle shear zones act as the sliding surfaces.The progressive destruction of the locked segments and the gradual penetration of brittle shear zones,driven by gravitational potential energy,contribute to the landslide occurrence.This research provides critical insights into the formation mechanisms of large-scale landslides within tectonic mélange belts.展开更多
Yunnan in southwest China is a geographically and ethnically complex region at the intersection of southern China and Southeast Asia,and a focal point for human migrations.To clarify its maternal genetic history,we ge...Yunnan in southwest China is a geographically and ethnically complex region at the intersection of southern China and Southeast Asia,and a focal point for human migrations.To clarify its maternal genetic history,we generated 152 complete mitogenomes from 17 Yunnan archaeological sites.Our results reveal distinct genetic histories segregated by geographical regions.Maternal lineages of ancient populations from northwestern and northern Yunnan exhibit closer affinities with past and present-day populations from northern East Asia and Xizang,providing important genetic evidence for the migration and interaction of populations along the Tibetan-Yi corridor since the Neolithic.Between 5500 and 1800 years ago,central Yunnan populations maintained their internal genetic relationships,including a 7000-year-old basal lineage of the rare and widely dispersed haplogroup M61.At the Xingyi site,changes in mitochondrial DNA haplogroups occurred between the Late Neolithic and Bronze Age,with haplogroups shifting from those predominant in the Yellow River region to those predominant in coastal southern China.These results highlight the high diversity of Yunnan populations during the Neolithic to Bronze Age.展开更多
In 2018,a catastrophic high-altitude landslide occurred at Baige,located within the tectonic suture zone of the Upper Jinsha River.The failure mechanism of this event remains poorly understood.This study aims to eluci...In 2018,a catastrophic high-altitude landslide occurred at Baige,located within the tectonic suture zone of the Upper Jinsha River.The failure mechanism of this event remains poorly understood.This study aims to elucidate the deformation characteristics and failure mechanism of the Baige landslide by employing a comprehensive methodology,including field geological surveys,analysis of historical remote sensing imagery,high-density electrical resistivity surveys,and advanced displacement monitoring.Additionally,the physical modeling experiments were conducted to replicate the unique failure modes.The findings propose a novel perspective on the failure mechanism of the Baige landslide,which involves two critical stages:first,the brittle shear zone bypasses and fails at the lower locked segment,and second,the failure of the upper locked segment,combined with the shear zone's impact on the lower locked segment,triggers overall slope instability.Physical modeling experiments revealed a transition from initial acceleration to a rapid acceleration phase,particularly marked by a significant increase in velocity following the failure of the upper locked segment.The intensity of acoustic emission signals was found to correlate with the failure of the locked segments and the state of particle collisions post-failure.It offers new insights into the failure mechanisms of tectonic mélange belt large-scale landslides in suture zones,contributing to the broader field of landslide research.展开更多
The enhancement of acid stress tolerance in yeast is critical for advancing its industrial application in biomanufacturing,given yeast's capacity to synthesize a wide range of acidic chemicals.Intracellular acidit...The enhancement of acid stress tolerance in yeast is critical for advancing its industrial application in biomanufacturing,given yeast's capacity to synthesize a wide range of acidic chemicals.Intracellular acidity can be mitigated by endogenous proton pumps;however,this process consumes substantial ATP(Adenosine Triphosphate)and imposes a metabolic burden on cells.To address this problem,this study introduced a light-driven proton pump in yeast to regulate intracellular acidity.The rhodopsin dR from Natrinema thermotolerans was expressed heterologously in Saccharomyces cerevisiae.However,it was found that dR could not be correctly localized to the plasma membrane.To realize its proton pump function,dR was relocated to the plasma membrane by fusing the signal peptide MLS to the N-terminus of dR.The activation of dR-mediated proton translocation across the membrane was successfully achieved through the application of light and retinene.The ability of the system to pump protons is enhanced with light intensity.This system significantly enhanced the survival ability of yeast in acidic environments.An increase in cell biomass of 6.6%was observed at a pH of 2.3 in comparison to the control.This study has expanded the application of photosensitive proteins for acid tolerance and provides a new strategy for the optimization of light-driven biosystems,which can help to enhancepotential of yeast in the biomanufacturing.展开更多
This study investigated the effect of Si addition on the microstructure and the silicide precipitation behavior in a novel near-βtitanium alloy.The results show that coarse and continuous silicides were preferentiall...This study investigated the effect of Si addition on the microstructure and the silicide precipitation behavior in a novel near-βtitanium alloy.The results show that coarse and continuous silicides were preferentially precipitated at the grain boundary during the solidification process,and theβgrain size of the as-cast alloy was refined.Dynamic recrystallization occurs under isothermal compression,and the silicide could inhibit the growth of recrystallized grains.The element redistribution and dislocation accumulation during hot deformation promote the dynamic precipitation of silicide,resulting in a discontinuous distribution of silicides at the grain boundaries.This work provides insight into how silicide dynamic precipitation will affect the microstructure and plastic deformation behavior of metal alloys.展开更多
Quaternary chalcogenides are viewed as a class of potential thermoelectric materials due to their good thermoelectric performance in the medium temperature region.In this work,carbon nanotubes(CNTs)with varying weight...Quaternary chalcogenides are viewed as a class of potential thermoelectric materials due to their good thermoelectric performance in the medium temperature region.In this work,carbon nanotubes(CNTs)with varying weight percentages are composited into the quaternary chalcogenide Cu_(2.1)Mn_(0.9)SnSe_(4)(CMTS)using a technique that combines ball-milling and hot-pressing,and the effect of CNTs on the thermoelectric performance of CMTS is investigated.The compositing of CNTs results in an increase in the intrinsic defects of CMTS,thereby enhancing the electrical conductivities of the composited samples.Besides,the addition of CNTs introduces various phonon scattering mechanisms,effectively restraining the lattice thermal conductivities of the composited samples,particularly in the low to medium temperature range.Ultimately,owing to the concurrent optimization of the power factor and thermal conductivity,the x=0.25 sample achieves a zT value of 0.37 at 673 K.The compositing of highly conductive secondary phase is recognized as a viable approach for the simultaneous enhancement of the thermoelectric properties of materials.展开更多
The effects of sub-transus(α+β)annealing treatment(ST),followed by single aging(SA)or duplex aging(DA)on the microstructural evolution and mechanical properties of near-βTi-4Al-1Sn-2Zr-5Mo-8V-2.5Cr(mass fraction,%)...The effects of sub-transus(α+β)annealing treatment(ST),followed by single aging(SA)or duplex aging(DA)on the microstructural evolution and mechanical properties of near-βTi-4Al-1Sn-2Zr-5Mo-8V-2.5Cr(mass fraction,%)alloy were investigated using optical microscopy,scanning electron microscopy,and transmission electron microscopy.The results show that the finer secondaryαphase precipitates in the alloy after DA than SA(e.g.,149 nm for SA and 69 nm for DA,both after ST at 720℃).The main reason is that the pre-aging step(300℃)in the DA process leads to the formation of intermediateωphase nanoparticles,which assist in the nucleation of the acicular secondaryαphase precipitates.In addition,the strength of the alloy after DA is higher than that of SA at the specific ST temperature.A good combination is achieved in the alloy subjected to ST at 750℃,followed by DA(UTS:1450 MPa,EL:3.87%),which is due to the precipitation of nanoscale secondaryαphase by DA.In conclusion,DA is a feasible process for this new near-βtitanium alloy.展开更多
基金supported by the Major Program of National Natural Science Foundation of China(Grant No.42090055)the National Key ScientificInstruments and Equipment Development Projects of China(Grant No.41827808)the National Nature Science Foundation of China(Grant No.42207216).
文摘Reservoir-induced landslides in China's Three Gorges Reservoir area are prone to tensile cracks due to the influenceof their own weight and fluctuationsin water levels.The presence of cracks indicates that the tensile stress in the area has exceeded the tensile strength of the soil,leading to local instability.To explore the impact of tensile failure behavior on the stability and failure modes of reservoir landslides,the Huangtupo Riverside Slump#1 is taken as a case study.By considering local tensile failure,potential tensile cracks are incorporated into the analysis via the limit equilibrium method and reliability theory.The reliability of landslides under different tensile failure scenarios is quantified.Strain-softening characteristics of the soil are combined to further analyze the failure transmission path of the landslide.Finally,these potential failure modes were validated through physical model tests.The results show that cracks developing at rear positions reduce the stability of the slope and increase the probability of instability.During the destruction process,retrogressive failures with multiple sliding surfaces are likely to occur.However,tensile failure at the forefront reduces the likelihood of an individual slide mass descending.Progressive failure results in both regular and skip transmission patterns.Additionally,cracks and water level changes can also lead to shifts in the positions of the most dangerous blocks.Therefore,in practical landslide analysis and prevention,it is necessary to consider local tensile damage and identify potential tensile crack locations in advance to optimize prevention measures and accurately evaluate landslide risk.
基金supported by the National Nature Science Foundation of China(Nos.52202335 and 52171227)Natural Science Foundation of Jiangsu Province(No.BK20221137)National Key R&D Program of China(2024YFE0108500).
文摘Wide-temperature applications of sodium-ion batteries(SIBs)are severely limited by the sluggish ion insertion/diffusion kinetics of conversion-type anodes.Quantum-sized transition metal dichalcogenides possess unique advantages of charge delocalization and enrich uncoordinated electrons and short-range transfer kinetics,which are crucial to achieve rapid low-temperature charge transfer and high-temperature interface stability.Herein,a quantum-scale FeS_(2) loaded on three-dimensional Ti_(3)C_(2) MXene skeletons(FeS_(2) QD/MXene)fabricated as SIBs anode,demonstrating impressive performance under wide-temperature conditions(−35 to 65).The theoretical calculations combined with experimental characterization interprets that the unsaturated coordination edges of FeS_(2) QD can induce delocalized electronic regions,which reduces electrostatic potential and significantly facilitates efficient Na+diffusion across a broad temperature range.Moreover,the Ti_(3)C_(2) skeleton reinforces structural integrity via Fe-O-Ti bonding,while enabling excellent dispersion of FeS_(2) QD.As expected,FeS_(2) QD/MXene anode harvests capacities of 255.2 and 424.9 mAh g^(−1) at 0.1 A g^(−1) under−35 and 65,and the energy density of FeS_(2) QD/MXene//NVP full cell can reach to 162.4 Wh kg^(−1) at−35,highlighting its practical potential for wide-temperatures conditions.This work extends the uncoordinated regions induced by quantum-size effects for exceptional Na^(+)ion storage and diffusion performance at wide-temperatures environment.
基金supported by the National Science and Technology Major Projects of China(Grant No.2016ZX05004002)PetroChina Science and Technology Project(Grant No.2019B-0406)the China Scholarship Council(No.201908080005)。
文摘An integrated petrographical and geochemical study of the massive dolomite of the lower Ordovician Penglaiba Formation of the Tarim Basin,outcropping at Yonganba recognized three dolomite types:very finely to finely crystalline nonplanar-a to planar-s dolomite(D1);medium crystalline planar-s to planar-e dolomite(D2);and coarse crystalline nonplanar-a dolomite(D3).All have been affected by burial.D1 and D2 dolomites developed initially before or during shallow burial and later recrystallized,whereas D3 dolomite replaced the initial limestone entirely during burial.All three dolomites have similar geochemical features.The D2 dolomite tends to have more inter-crystalline pores(inherited from primary pores)and higher porosity due to its outstanding compaction resistance during shallow burial;whereas D3 dolomite does not retain appreciable primary pores due to strong cementation and pressure dissolution before dolomitization.This study provides a useful model for understanding the origin and porosity development of burial dolomite,in particular Paleozoic dolomite.
基金supported by the National Natural Science Foundation of China(82401772)the Shanghai Municipal Education Commission(2021-01-07-00-02-E0086).
文摘Post-traumatic stress disorder(PTSD)is a severe neuropsychiatric disorder characterised by reexperiencing,avoidance and hyperarousal.Memory abnormalities manifested as intrusive thoughts and prolonged distressful emotions are postulated as key roles in PTSD development and persistence.Over the past decades,convergent results from human and animal studies have systematically investigated contributions of the amygdala,hippocampus and medial prefrontal cortex(mPFC)in fear memory processes,including fear acquisition,storage,reconsolidation and extinction.These findings provide mechanistic insights for cognitive-behavioural therapy and aid in developing pathological region-targeted neuromodulation treatment for PTSD.Taking advantage of advances in cell-type selective labelling and manipulation technologies,recent studies have focused on the spatiotemporal regulation of neural circuits underlying distinct phases of fear memory processes.These findings have revealed that multiple distributed brain areas participate in the fear memory encoding network.Moreover,the functional role of distinct neuronal ensembles within the amygdala-hippocampus-mPFC pathway,identified by genetic markers and projection profiles,has been assigned to temporally separate features of fear processing,demonstrating the sophistication of the fear encoding circuit.These results provide mechanistic insights into PTSD pathology and might shed light on aetiology-based clinical interventions for PTSD.Therefore,the present review will mainly focus on the recent progress in elucidating neural circuit mechanisms underlying the dynamic regulation of fear memory,with an emphasis on the spatial distribution of fear memory encoding neural networks and the temporal coherence between neuronal ensemble activity and fear expression.
基金supported by the National Major Scientific Instruments and Equipment Development Projects of China(No.41827808)the Major Program of the National Natural Science Foundation of China(No.42090055)Supported by Science and Technology Projects of Xizang Autonomous Region,China(No.XZ202402ZD0001)。
文摘In 2018,Baige,Xizang,witnessed two consecutive large-scale landslides,causing significant damage and drawing widespread attention.From March 2011 to February 2018,the Baige landslide exhibited a 50-m displacement without complete failure,culminating in a collapse in October 2018.The mechanisms behind its resistance to failure despite substantial deformation and the influence of the complex geo-structure within the tectonic mélange belt remain unclear.To address these questions,this study utilized a multidisciplinary approach,integrating on-site geological field mapping,surface deformation monitoring,multielectrode resistivity method,and deep displacement analysis.The aim was to evaluate the impact of the intricate geo-structure within the tectonic mélange belt on the Baige landslide events.Findings reveal that the landslide's geo-structure consists of structurally fractured,mesh-like rock masses,including heterogeneous lenticular rock masses and intermittent brittle shear zones distributed around the lens-shaped rock masses.The study underscores that the inhomogeneous and weakly deformed lenticular rock masses function as natural locked segments,governing the stability of the Baige landslide.Specifically,the relatively intact and hard granodiorite porphyry play a crucial role in locking the landslide's deformation.Deep displacement analysis indicates that the brittle shear zones act as the sliding surfaces.The progressive destruction of the locked segments and the gradual penetration of brittle shear zones,driven by gravitational potential energy,contribute to the landslide occurrence.This research provides critical insights into the formation mechanisms of large-scale landslides within tectonic mélange belts.
基金supported by the National Natural Science Foundation of China(41925009)National Key R&D Program of China(2022YFE0203800)+2 种基金the Ministry of Finance of the People’s Republic of China(YSBR-019)Science and Technology Innovation Team of Shaanxi Province(2024RS-CXTD-74)Xiaohong Wu was supported by the Key National Social Science Foundation of China(No.16ZDA144).
文摘Yunnan in southwest China is a geographically and ethnically complex region at the intersection of southern China and Southeast Asia,and a focal point for human migrations.To clarify its maternal genetic history,we generated 152 complete mitogenomes from 17 Yunnan archaeological sites.Our results reveal distinct genetic histories segregated by geographical regions.Maternal lineages of ancient populations from northwestern and northern Yunnan exhibit closer affinities with past and present-day populations from northern East Asia and Xizang,providing important genetic evidence for the migration and interaction of populations along the Tibetan-Yi corridor since the Neolithic.Between 5500 and 1800 years ago,central Yunnan populations maintained their internal genetic relationships,including a 7000-year-old basal lineage of the rare and widely dispersed haplogroup M61.At the Xingyi site,changes in mitochondrial DNA haplogroups occurred between the Late Neolithic and Bronze Age,with haplogroups shifting from those predominant in the Yellow River region to those predominant in coastal southern China.These results highlight the high diversity of Yunnan populations during the Neolithic to Bronze Age.
基金supported by the National Major Scientific Instruments and Equipment Development Projects of China(No.41827808)the Major Program of the National Natural Science Foundation of China(No.42090055)Supported by Science and Technology Projects of Xizang Autonomous Region,China(No.XZ202402ZD0001)。
文摘In 2018,a catastrophic high-altitude landslide occurred at Baige,located within the tectonic suture zone of the Upper Jinsha River.The failure mechanism of this event remains poorly understood.This study aims to elucidate the deformation characteristics and failure mechanism of the Baige landslide by employing a comprehensive methodology,including field geological surveys,analysis of historical remote sensing imagery,high-density electrical resistivity surveys,and advanced displacement monitoring.Additionally,the physical modeling experiments were conducted to replicate the unique failure modes.The findings propose a novel perspective on the failure mechanism of the Baige landslide,which involves two critical stages:first,the brittle shear zone bypasses and fails at the lower locked segment,and second,the failure of the upper locked segment,combined with the shear zone's impact on the lower locked segment,triggers overall slope instability.Physical modeling experiments revealed a transition from initial acceleration to a rapid acceleration phase,particularly marked by a significant increase in velocity following the failure of the upper locked segment.The intensity of acoustic emission signals was found to correlate with the failure of the locked segments and the state of particle collisions post-failure.It offers new insights into the failure mechanisms of tectonic mélange belt large-scale landslides in suture zones,contributing to the broader field of landslide research.
基金supported by the National Key Research and Development Program of China(2023YFA0913600)the National Natural Science Foundation of China(22138006,22278240).
文摘The enhancement of acid stress tolerance in yeast is critical for advancing its industrial application in biomanufacturing,given yeast's capacity to synthesize a wide range of acidic chemicals.Intracellular acidity can be mitigated by endogenous proton pumps;however,this process consumes substantial ATP(Adenosine Triphosphate)and imposes a metabolic burden on cells.To address this problem,this study introduced a light-driven proton pump in yeast to regulate intracellular acidity.The rhodopsin dR from Natrinema thermotolerans was expressed heterologously in Saccharomyces cerevisiae.However,it was found that dR could not be correctly localized to the plasma membrane.To realize its proton pump function,dR was relocated to the plasma membrane by fusing the signal peptide MLS to the N-terminus of dR.The activation of dR-mediated proton translocation across the membrane was successfully achieved through the application of light and retinene.The ability of the system to pump protons is enhanced with light intensity.This system significantly enhanced the survival ability of yeast in acidic environments.An increase in cell biomass of 6.6%was observed at a pH of 2.3 in comparison to the control.This study has expanded the application of photosensitive proteins for acid tolerance and provides a new strategy for the optimization of light-driven biosystems,which can help to enhancepotential of yeast in the biomanufacturing.
基金funded by the National Natural Science Foundation of China(Nos.52371117,52171122,52275362)the Central Government Guides the Special Fund Projects of Local Scientific and Technological Development,China(Nos.YDZJSX2021A016,YDZX-20191400002149)+1 种基金the Key Project of Natural Science Foundation of Ningxia,China(No.2022AAC02077)the Natural Science Foundation of Shanxi Province,China(No.20210302124077)。
文摘This study investigated the effect of Si addition on the microstructure and the silicide precipitation behavior in a novel near-βtitanium alloy.The results show that coarse and continuous silicides were preferentially precipitated at the grain boundary during the solidification process,and theβgrain size of the as-cast alloy was refined.Dynamic recrystallization occurs under isothermal compression,and the silicide could inhibit the growth of recrystallized grains.The element redistribution and dislocation accumulation during hot deformation promote the dynamic precipitation of silicide,resulting in a discontinuous distribution of silicides at the grain boundaries.This work provides insight into how silicide dynamic precipitation will affect the microstructure and plastic deformation behavior of metal alloys.
基金supported by the National Natural Science Foundation of China(Nos.52171216 and 52472221)the Qilu Young Scholar Program of Shandong University and Core Facility Sharing Platform of Shandong University.
文摘Quaternary chalcogenides are viewed as a class of potential thermoelectric materials due to their good thermoelectric performance in the medium temperature region.In this work,carbon nanotubes(CNTs)with varying weight percentages are composited into the quaternary chalcogenide Cu_(2.1)Mn_(0.9)SnSe_(4)(CMTS)using a technique that combines ball-milling and hot-pressing,and the effect of CNTs on the thermoelectric performance of CMTS is investigated.The compositing of CNTs results in an increase in the intrinsic defects of CMTS,thereby enhancing the electrical conductivities of the composited samples.Besides,the addition of CNTs introduces various phonon scattering mechanisms,effectively restraining the lattice thermal conductivities of the composited samples,particularly in the low to medium temperature range.Ultimately,owing to the concurrent optimization of the power factor and thermal conductivity,the x=0.25 sample achieves a zT value of 0.37 at 673 K.The compositing of highly conductive secondary phase is recognized as a viable approach for the simultaneous enhancement of the thermoelectric properties of materials.
基金the financial supports from the Key Research and Development Program of Shanxi Province,China(Nos.201903D421084,201903D121056)the National Natural Science Foundation of China(Nos.52171122,52071228,51901151)。
文摘The effects of sub-transus(α+β)annealing treatment(ST),followed by single aging(SA)or duplex aging(DA)on the microstructural evolution and mechanical properties of near-βTi-4Al-1Sn-2Zr-5Mo-8V-2.5Cr(mass fraction,%)alloy were investigated using optical microscopy,scanning electron microscopy,and transmission electron microscopy.The results show that the finer secondaryαphase precipitates in the alloy after DA than SA(e.g.,149 nm for SA and 69 nm for DA,both after ST at 720℃).The main reason is that the pre-aging step(300℃)in the DA process leads to the formation of intermediateωphase nanoparticles,which assist in the nucleation of the acicular secondaryαphase precipitates.In addition,the strength of the alloy after DA is higher than that of SA at the specific ST temperature.A good combination is achieved in the alloy subjected to ST at 750℃,followed by DA(UTS:1450 MPa,EL:3.87%),which is due to the precipitation of nanoscale secondaryαphase by DA.In conclusion,DA is a feasible process for this new near-βtitanium alloy.
