Sodium-ion conducting materials in sodium-ion battery have drawn widespread attention in energy storage technologies due to the advantages of low cost,high performance,and efficient environmental adaptability.Herein,b...Sodium-ion conducting materials in sodium-ion battery have drawn widespread attention in energy storage technologies due to the advantages of low cost,high performance,and efficient environmental adaptability.Herein,bond valence site energy(BVSE)calculations were used to predict the sodium ion electrical performances by the Na nonstoichiometric modifications,and we have carried out fine experiments to modulate the sodium ion conductivity of Na_(x)Zn_(2)TeO_(6) guided by BVSE calculations.The optimized composition Na_(2.1)Zn_(2)TeO_(6) shows the superior sodium ionic conductivity of 5.3×10^(−3) S/cm at 190℃,with a low activation energy of 0.28 eV.The excess Na preferentially occupies the Na1 site with tetrahedral voids,which has a higher capacity for sodium ion migration,as revealed by the combined neutron powder diffraction technique with the 1D and 2D ^(23)Na solid-state NMR technique,which is responsible for the variations in sodium ion conductivity.In addition,it is worth noting that the resulting Na_(2.1)Zn_(2)TeO_(6) material maintains superior thermal and phase stability,as well as approximately the same thermal expansion coefficient values even during the temperature rise and fall cycles in the temperature range of 25–800°C.Furthermore,molecular dynamics simulations revealed that the sodium ions exhibit longrange anisotropic migration within the Na+interlayers of Na_(2.1)Zn_(2)TeO_(6).展开更多
Some refractory linings that protect metallic vessels from the hot temperature of the products they contain are made of masonries with or without mortar.The joints play an important role,reducing the stresses in the m...Some refractory linings that protect metallic vessels from the hot temperature of the products they contain are made of masonries with or without mortar.The joints play an important role,reducing the stresses in the masonries during heating.Furthermore,the presence of these joints makes the behaviour of the masonry nonlinear and orthotropic.To perform a thermomechanical simulation using a finite element method of an industrial vessel that contains hundreds or thousands of bricks and joints,microscopic models are not suitable due to the high computational time and the management of the behaviour of the joints(opening/closing)which affects the convergence.To overcome these problems,it is proposed to replace the masonry by a homogeneous material that has a behaviour equivalent to the set of bricks and joints,using a periodic homogenization technique.Since the joints can be closed or open,the equivalent material will have a different behaviour according to the joint state.Furthermore,refractory materials have an elastic-viscoplastic behaviour at high temperatures.So,the equivalent material will have an orthotropic elastic-viscoplastic behaviour,requiring a nonlinear homogenisation technique.An overview of this approach developed at University of Orléans is presented with two industrial applications(blast-furnace and steel ladle).展开更多
Crypto assets have become increasingly popular in recent years due to their many advantages,such as low transaction costs and investment opportunities.The performance of crypto exchanges is an essential factor in deve...Crypto assets have become increasingly popular in recent years due to their many advantages,such as low transaction costs and investment opportunities.The performance of crypto exchanges is an essential factor in developing crypto assets.Therefore,it is necessary to take adequate measures regarding the reliability,speed,user-friendliness,regulation,and supervision of crypto exchanges.However,each measure to be taken creates extra costs for businesses.Studies are needed to determine the factors that most affect the performance of crypto exchanges.This study develops an integrated framework,i.e.,fuzzy best-worst method with the Heronian function—the fuzzy measurement of alternatives and ranking according to compromise solution with the Heronian function(FBWM’H-FMARCOS’H),to evaluate cryptocurrency exchanges.In this framework,the fuzzy best-worst method(FBWM)is used to decide the criteria’s importance,fuzzy measurement of alternatives and ranking according to compromise solution(FMARCOS)is used to prioritize the alternatives,and the Heronian function is used to aggregate the results.Integrating a modified FBWM and FMARCOS with Heronian functions is particularly appealing for group decision-making under vagueness.Through case studies,some well-known cryptocurrency exchanges operating in Türkiye are assessed based on seven critical factors in the cryptocurrency exchange evaluation process.The main contribution of this study is generating new priority strategies to increase the performance of crypto exchanges with a novel decision-making methodology.“Perception of security,”“reputation,”and“commission rate”are found as the foremost factors in choosing an appropriate cryptocurrency exchange for investment.Further,the best score is achieved by Coinbase,followed by Binance.The solidity and flexibility of the methodology are also supported by sensitivity and comparative analyses.The findings may pave the way for investors to take appropriate actions without incurring high costs.展开更多
The base of the ICS(International Commission on Stratigraphy)Geological Time Scale was ratified in 2022 by defining a new Global Stratigraphic Standard Age(GSSA)for the lower boundary of the Hadean Eon(formerly 4000–...The base of the ICS(International Commission on Stratigraphy)Geological Time Scale was ratified in 2022 by defining a new Global Stratigraphic Standard Age(GSSA)for the lower boundary of the Hadean Eon(formerly 4000–3600 Ma);the age of the Solar System based on the oldest solids,calcium-aluminium inclusions(CAIs),generated in the protoplanetary disk.The formal GSSA for the Hadean base is the oldest reliable,weighted mean Ucorrected Pb–Pb age of 4567.30±0.16 Ma obtained for CAIs in primitive meteorites Allende and Efremovka.This age is supported by the 4568–4567 Ma U-corrected Pb–Pb ages of chondrules in Northwest African meteorites.The boundary sets an upper lifetime for the protoplanetary disk and timing of planet formation.展开更多
The Tianshan range could have been built by both late Early Paleozoicaccretion and Late Paleozoic collision events. The late Early Paleozoic Aqqikkudug-Weiya suture ismarked by Ordovician ophiolitic melange and a Silu...The Tianshan range could have been built by both late Early Paleozoicaccretion and Late Paleozoic collision events. The late Early Paleozoic Aqqikkudug-Weiya suture ismarked by Ordovician ophiolitic melange and a Silurian flysch sequence, high-pressure metamorphicrelics, and mylonitized rocks. The Central Tianshan belt could principally be an Ordovician volcanicarc; whereas the South Tianshan belt, a back-arc basin. Macro- and microstructures, along withunconformities, provide some kinematic and chronological constraints on 2-phase ductile deformation.The earlier ductile deformation occurring at ca. 400 Ma was marked by north-verging ductileshearing, yielding granulite-bearing ophiolitic melange blocks and garnet-pyroxene-facies ductiledeformation, and the later deformation, a dextral strike-slip tectonic process, occurred during theLate Carboniferous-Early Permian. Early Carboniferous molasses were deposited unconformably onpre-Carboniferous metamorphic and ductilely sheared rocks, implying the end of the early orogeny.The large-scale ductile strike-slip along the Aqqikkudug-Weiya zone was possibly caused by thesecond tectonic event, the Hercynian collision between the northern Tarim block and the southernSiberian block. Late Paleozoic granitic magmatism and superimposed structures overprinted this EarlyPaleozoic deformation belt. Results of geometric and kinematic studies suggest that the primaryframework of the Southern-Central Tianshan belt, at least the eastern part of the Tianshan belt, wasbuilt by these two phases of accretion events.展开更多
The Trans-North China Belt （TNCB） is a Paleoproterozoic collisional orogen （ca. 1.9-1.8 Ga） responsible for the amalgamation of the North China Craton. Detailed field works in Liiliangshan, Hengshan, Wutaishan and...The Trans-North China Belt （TNCB） is a Paleoproterozoic collisional orogen （ca. 1.9-1.8 Ga） responsible for the amalgamation of the North China Craton. Detailed field works in Liiliangshan, Hengshan, Wutaishan and Fuping massifs where the belt is well exposed, allow us to draw a new tectonic map and crustal-scale cross sections. The available petrologic, radiometric, geochronologic data are integrated in a geodynamic evolution scheme for this orogen. The Low Grade Mafic Unit （LGMU） is interpreted as an ophiolitic nappe rooted in a suture zone located in the western part of the Lüliangshan. This ophiolitic nappe overthrusts to the SE upon the Orthogneiss-Volcanites Unit （OVU） that consists of a bimodal volcanic-sedimentary series metamorphosed under amphibolite facies conditions intruded by calcalkaline orthogneiss. The OVU is a composite Neoarchean-Paleoproterozoic magmatic arc developed during two stages （ca. 2500 and 2100 Ma） upon a continental basement corresponding to the western extension of the Neoarchean Fuping massif The OVU overthrusts to the SE the Fuping massif along the Longquanguan shear zone. This stack of nappes, coeval with an amphibolite facies metamorphism, is dated at ca. 1880 Ma. Subsequently, the metamorphic series experienced a widespread migmatization at 1850 Ma and was intruded by post-orogenic plutons dated at 1800 Ma. The weakly to unmetamorphosed Hutuo Supergroup unconformably overlies the metamorphosed and ductilely deformed units （OVU and LGMU）, but it is also involved in a second tectonic phase developed in subsurface conditions. These structural features lead us to question the ca. 2090 Ma age attributed to the Hutuo supergroup. Moreover, in the Fuping massif several structural and magmatic lines of evidence argue for an earlier orogenic event at ca. 2100 Ma that we relate to an older west-directed subduction below the Fuping Block. The Taihangshan Fault might be the location of a possible suture zone between the Fuping Block and an eastern one. A geodynamic model at variance with previous ones, is proposed to account for the formation of the TNCB. In this scheme, three Archean continents, namely from west to east, the Ordos, Fuping and Eastern Blocks are separated by the Lüliang and Taihang Oceans. The closure of the Taihang Ocean at ca. 2100 Ma by westward subduction below the Fuping Block accounts for the arc magmatism and the 2100 Ma orogeny. The second collision at 1900-1880 Ma between the Fuping and Ordos blocks is responsible for the main structural metamorphic and magmatic features of the Trans-North China Belt.展开更多
In the last few decades, the Late Paleozoic-Early Mesozoic tectonic evolution of South China has been quite controversial. The focus of debate is on both the age of ophiolites and the Late Paleozoic-Early Mesozoic geo...In the last few decades, the Late Paleozoic-Early Mesozoic tectonic evolution of South China has been quite controversial. The focus of debate is on both the age of ophiolites and the Late Paleozoic-Early Mesozoic geological and geodynamic environment. The Huaiyu Domain is located in the NE part of South China and exposes numerous significant geological features that are keys to understand the tectonics of South China. In this paper, we present some new evidence on stratigraphy, petrology and SHRIMP zircon U-Pb geochronology, and together with other geological and geochemical data available in the literature, and the following conclusions are suggested： 1） The eastern Jiangnan ophiolites belt, dated at 858±11 Ma by SHRIMP zircon U-Pb method, was generated during the Neoproterozoic, but not the Late Paleozoic; 2） The sedimentary rocks associated with these oceanic rocks do not contain radiolarians but Neoproterozoic acritarchs; 3） During Permian-Early Triassic times, the Huaiyu Domain was dominantly characterized by a shallow sea depositional environment since deep sea sediments are absent; and 4） The pre-Devonian tectonics of South China has been reworked by late polyphase tectonism through the Triassic and the Cretaceous periods. A Late Paleozoic-Early Mesozoic deep marine domain floored by oceanic crust never existed in the study area. The geochronological and structural data do not comply with a Late Paleozoic-Early Mesozoic South China Ocean.展开更多
Ultrasonic imaging is becoming the most popular medical imaging modality,owing to the low price per examination and its safety.However,blood is a poor scatterer of ultrasound waves at clinical diagnostic transmit freq...Ultrasonic imaging is becoming the most popular medical imaging modality,owing to the low price per examination and its safety.However,blood is a poor scatterer of ultrasound waves at clinical diagnostic transmit frequencies.For perfusion imaging,markers have been designed to enhance the contrast in B-mode imaging.These so-called ultrasound contrast agents consist of microscopically small gas bubbles encapsulated in biodegradable shells.In this review,the physical principles of ultrasound contrast agent microbubble behavior and their adjustment for drug delivery including sonoporation are described.Furthermore,an outline of clinical imaging applications of contrast-enhanced ultrasound is given.It is a challenging task to quantify and predict which bubble phenomenon occurs under which acoustic condition,and how these phenomena may be utilized in ultrasonic imaging.Aided by high-speed photography,our improved understanding of encapsulated microbubble behavior will lead to more sophisticated detection and delivery techniques.More sophisticated methods use quantitative approaches to measure the amount and the time course of bolus or reperfusion curves,and have shown great promise in revealing effective tumor responses to anti-angiogenic drugs in humans before tumor shrinkage occurs.These are beginning to be accepted into clinical practice.In the long term,targeted microbubbles for molecular imaging and eventually for directed anti-tumor therapy are expected to be tested.展开更多
To date there is no treatment able to stop or slow down the loss of dopaminergic neurons that characterizes Parkinson’s disease.It was recently observed in a rodent model of Alzheimer’s disease that the interaction ...To date there is no treatment able to stop or slow down the loss of dopaminergic neurons that characterizes Parkinson’s disease.It was recently observed in a rodent model of Alzheimer’s disease that the interaction between the α7 subtype of nicotinic acetylcholine receptor(α7-nAChR)and sigma-1 receptor(σ1-R)could exert neuroprotective effects through the modulation of neuroinflammation which is one of the key components of the pathophysiology of Parkinson’s disease.In this context,the aim of the present study was to assess the effects of the concomitant administration of N-(3R)-1-azabicyclo[2.2.2]oct-3-yl-furo[2,3-c]pyridine-5-carboxamide(PHA)543613 as an α7-nAChR agonist and 2-(4-morpholinethyl)1-phenylcyclohexanecarboxylate(PRE)-084 as aσ1-R agonist in a well-characterized 6-hydroxydopamine rat model of Parkinson’s disease.The animals received either vehicle separately or the dual therapy PHA/PRE once a day until day 14 postlesion.Although no effect was noticed in the amphetamine-induced rotation test,our data has shown that the PHA/PRE treatment induced partial protection of the dopaminergic neurons(15-20%),assessed by the dopamine transporter density in the striatum and immunoreactive tyrosine hydroxylase in the substantia nigra.Furthermore,this dual therapy reduced the degree of glial activation consecutive to the 6-hydroxydopamine lesion,i.e,the 18 kDa translocation protein density and glial fibrillary acidic protein staining in the striatum,and the CD11b and glial fibrillary acidic protein staining in the substantia nigra.Hence,this study reports for the first time that concomitant activation of α7-nAChR andσ1-R can provide a partial recovery of the nigro-striatal dopaminergic neurons through the modulation of microglial activation.The study was approved by the Regional Ethics Committee(CEEA Val de Loire n°19)validated this protocol(Authorization N°00434.02)on May 15,2014.展开更多
Chinese East Tianshan is a key area for understanding the Paleozoic accretion of the southern Central Asian Orogenic Belt. A first accretion-collision stage, before the Visean, developed the Eo-Tianshan range, which e...Chinese East Tianshan is a key area for understanding the Paleozoic accretion of the southern Central Asian Orogenic Belt. A first accretion-collision stage, before the Visean, developed the Eo-Tianshan range, which exhibits north-verging structures. The geodynamic evolution included： i） Ordovician-Early Devonian southward subduction of a Central Tianshan ocean beneath a Central Tianshan arc; ii） Devonian oceanic closure and collision between Central Tianshan arc and Iqli-North Tianshan block, along the Central Tianshan Suture Zone; iii） Late Devonian-earliest Carboniferous closure of a South Tianshan back-arc basin, and subsequent Central Tianshan-Tarim active margin colli- sion along the South Tianshan Suture Zone. A second stage involved： i） Late Devonian-Carboniferous south- ward subduction of North Tianshan ocean beneath the Eo-Tianshan active margin （Yili-North Tianshan arc）;展开更多
基金supported by the National Natural Science Foundation of China(Nos.22205017,22090043)the Guangxi Natural Science Foundation,China(No.2019GXNSFGA245006)the Guilin University of Technology Research Startup Project,China(No.RD2400002912).
文摘Sodium-ion conducting materials in sodium-ion battery have drawn widespread attention in energy storage technologies due to the advantages of low cost,high performance,and efficient environmental adaptability.Herein,bond valence site energy(BVSE)calculations were used to predict the sodium ion electrical performances by the Na nonstoichiometric modifications,and we have carried out fine experiments to modulate the sodium ion conductivity of Na_(x)Zn_(2)TeO_(6) guided by BVSE calculations.The optimized composition Na_(2.1)Zn_(2)TeO_(6) shows the superior sodium ionic conductivity of 5.3×10^(−3) S/cm at 190℃,with a low activation energy of 0.28 eV.The excess Na preferentially occupies the Na1 site with tetrahedral voids,which has a higher capacity for sodium ion migration,as revealed by the combined neutron powder diffraction technique with the 1D and 2D ^(23)Na solid-state NMR technique,which is responsible for the variations in sodium ion conductivity.In addition,it is worth noting that the resulting Na_(2.1)Zn_(2)TeO_(6) material maintains superior thermal and phase stability,as well as approximately the same thermal expansion coefficient values even during the temperature rise and fall cycles in the temperature range of 25–800°C.Furthermore,molecular dynamics simulations revealed that the sodium ions exhibit longrange anisotropic migration within the Na+interlayers of Na_(2.1)Zn_(2)TeO_(6).
基金the PhD students(M.Ali,J.Brulin,M.Landreau,T.M.H Nguyen)who have participated to this study,the different compagnies(CPM,RHI-Magnesita,Saint-Gobain,and Tata Steel),the European Commission(ATHOR project,764987 Grant)the Federation for International Refractory Research and Education which have funded it.
文摘Some refractory linings that protect metallic vessels from the hot temperature of the products they contain are made of masonries with or without mortar.The joints play an important role,reducing the stresses in the masonries during heating.Furthermore,the presence of these joints makes the behaviour of the masonry nonlinear and orthotropic.To perform a thermomechanical simulation using a finite element method of an industrial vessel that contains hundreds or thousands of bricks and joints,microscopic models are not suitable due to the high computational time and the management of the behaviour of the joints(opening/closing)which affects the convergence.To overcome these problems,it is proposed to replace the masonry by a homogeneous material that has a behaviour equivalent to the set of bricks and joints,using a periodic homogenization technique.Since the joints can be closed or open,the equivalent material will have a different behaviour according to the joint state.Furthermore,refractory materials have an elastic-viscoplastic behaviour at high temperatures.So,the equivalent material will have an orthotropic elastic-viscoplastic behaviour,requiring a nonlinear homogenisation technique.An overview of this approach developed at University of Orléans is presented with two industrial applications(blast-furnace and steel ladle).
文摘Crypto assets have become increasingly popular in recent years due to their many advantages,such as low transaction costs and investment opportunities.The performance of crypto exchanges is an essential factor in developing crypto assets.Therefore,it is necessary to take adequate measures regarding the reliability,speed,user-friendliness,regulation,and supervision of crypto exchanges.However,each measure to be taken creates extra costs for businesses.Studies are needed to determine the factors that most affect the performance of crypto exchanges.This study develops an integrated framework,i.e.,fuzzy best-worst method with the Heronian function—the fuzzy measurement of alternatives and ranking according to compromise solution with the Heronian function(FBWM’H-FMARCOS’H),to evaluate cryptocurrency exchanges.In this framework,the fuzzy best-worst method(FBWM)is used to decide the criteria’s importance,fuzzy measurement of alternatives and ranking according to compromise solution(FMARCOS)is used to prioritize the alternatives,and the Heronian function is used to aggregate the results.Integrating a modified FBWM and FMARCOS with Heronian functions is particularly appealing for group decision-making under vagueness.Through case studies,some well-known cryptocurrency exchanges operating in Türkiye are assessed based on seven critical factors in the cryptocurrency exchange evaluation process.The main contribution of this study is generating new priority strategies to increase the performance of crypto exchanges with a novel decision-making methodology.“Perception of security,”“reputation,”and“commission rate”are found as the foremost factors in choosing an appropriate cryptocurrency exchange for investment.Further,the best score is achieved by Coinbase,followed by Binance.The solidity and flexibility of the methodology are also supported by sensitivity and comparative analyses.The findings may pave the way for investors to take appropriate actions without incurring high costs.
文摘The base of the ICS(International Commission on Stratigraphy)Geological Time Scale was ratified in 2022 by defining a new Global Stratigraphic Standard Age(GSSA)for the lower boundary of the Hadean Eon(formerly 4000–3600 Ma);the age of the Solar System based on the oldest solids,calcium-aluminium inclusions(CAIs),generated in the protoplanetary disk.The formal GSSA for the Hadean base is the oldest reliable,weighted mean Ucorrected Pb–Pb age of 4567.30±0.16 Ma obtained for CAIs in primitive meteorites Allende and Efremovka.This age is supported by the 4568–4567 Ma U-corrected Pb–Pb ages of chondrules in Northwest African meteorites.The boundary sets an upper lifetime for the protoplanetary disk and timing of planet formation.
基金the supports from the National 973 Project on Westemn China (No.2001CB409804)the National Natural Science Foundation of China (grants 49772151 , 49832040)
文摘The Tianshan range could have been built by both late Early Paleozoicaccretion and Late Paleozoic collision events. The late Early Paleozoic Aqqikkudug-Weiya suture ismarked by Ordovician ophiolitic melange and a Silurian flysch sequence, high-pressure metamorphicrelics, and mylonitized rocks. The Central Tianshan belt could principally be an Ordovician volcanicarc; whereas the South Tianshan belt, a back-arc basin. Macro- and microstructures, along withunconformities, provide some kinematic and chronological constraints on 2-phase ductile deformation.The earlier ductile deformation occurring at ca. 400 Ma was marked by north-verging ductileshearing, yielding granulite-bearing ophiolitic melange blocks and garnet-pyroxene-facies ductiledeformation, and the later deformation, a dextral strike-slip tectonic process, occurred during theLate Carboniferous-Early Permian. Early Carboniferous molasses were deposited unconformably onpre-Carboniferous metamorphic and ductilely sheared rocks, implying the end of the early orogeny.The large-scale ductile strike-slip along the Aqqikkudug-Weiya zone was possibly caused by thesecond tectonic event, the Hercynian collision between the northern Tarim block and the southernSiberian block. Late Paleozoic granitic magmatism and superimposed structures overprinted this EarlyPaleozoic deformation belt. Results of geometric and kinematic studies suggest that the primaryframework of the Southern-Central Tianshan belt, at least the eastern part of the Tianshan belt, wasbuilt by these two phases of accretion events.
文摘The Trans-North China Belt （TNCB） is a Paleoproterozoic collisional orogen （ca. 1.9-1.8 Ga） responsible for the amalgamation of the North China Craton. Detailed field works in Liiliangshan, Hengshan, Wutaishan and Fuping massifs where the belt is well exposed, allow us to draw a new tectonic map and crustal-scale cross sections. The available petrologic, radiometric, geochronologic data are integrated in a geodynamic evolution scheme for this orogen. The Low Grade Mafic Unit （LGMU） is interpreted as an ophiolitic nappe rooted in a suture zone located in the western part of the Lüliangshan. This ophiolitic nappe overthrusts to the SE upon the Orthogneiss-Volcanites Unit （OVU） that consists of a bimodal volcanic-sedimentary series metamorphosed under amphibolite facies conditions intruded by calcalkaline orthogneiss. The OVU is a composite Neoarchean-Paleoproterozoic magmatic arc developed during two stages （ca. 2500 and 2100 Ma） upon a continental basement corresponding to the western extension of the Neoarchean Fuping massif The OVU overthrusts to the SE the Fuping massif along the Longquanguan shear zone. This stack of nappes, coeval with an amphibolite facies metamorphism, is dated at ca. 1880 Ma. Subsequently, the metamorphic series experienced a widespread migmatization at 1850 Ma and was intruded by post-orogenic plutons dated at 1800 Ma. The weakly to unmetamorphosed Hutuo Supergroup unconformably overlies the metamorphosed and ductilely deformed units （OVU and LGMU）, but it is also involved in a second tectonic phase developed in subsurface conditions. These structural features lead us to question the ca. 2090 Ma age attributed to the Hutuo supergroup. Moreover, in the Fuping massif several structural and magmatic lines of evidence argue for an earlier orogenic event at ca. 2100 Ma that we relate to an older west-directed subduction below the Fuping Block. The Taihangshan Fault might be the location of a possible suture zone between the Fuping Block and an eastern one. A geodynamic model at variance with previous ones, is proposed to account for the formation of the TNCB. In this scheme, three Archean continents, namely from west to east, the Ordos, Fuping and Eastern Blocks are separated by the Lüliang and Taihang Oceans. The closure of the Taihang Ocean at ca. 2100 Ma by westward subduction below the Fuping Block accounts for the arc magmatism and the 2100 Ma orogeny. The second collision at 1900-1880 Ma between the Fuping and Ordos blocks is responsible for the main structural metamorphic and magmatic features of the Trans-North China Belt.
基金This study is financially supported by grants from the National Natural Science Foundation of China （grant nos. 40221301, 40634022, and 40572118） and Ministry of Education in China （grant nos. 306007 and 20060284008）.
文摘In the last few decades, the Late Paleozoic-Early Mesozoic tectonic evolution of South China has been quite controversial. The focus of debate is on both the age of ophiolites and the Late Paleozoic-Early Mesozoic geological and geodynamic environment. The Huaiyu Domain is located in the NE part of South China and exposes numerous significant geological features that are keys to understand the tectonics of South China. In this paper, we present some new evidence on stratigraphy, petrology and SHRIMP zircon U-Pb geochronology, and together with other geological and geochemical data available in the literature, and the following conclusions are suggested： 1） The eastern Jiangnan ophiolites belt, dated at 858±11 Ma by SHRIMP zircon U-Pb method, was generated during the Neoproterozoic, but not the Late Paleozoic; 2） The sedimentary rocks associated with these oceanic rocks do not contain radiolarians but Neoproterozoic acritarchs; 3） During Permian-Early Triassic times, the Huaiyu Domain was dominantly characterized by a shallow sea depositional environment since deep sea sediments are absent; and 4） The pre-Devonian tectonics of South China has been reworked by late polyphase tectonism through the Triassic and the Cretaceous periods. A Late Paleozoic-Early Mesozoic deep marine domain floored by oceanic crust never existed in the study area. The geochronological and structural data do not comply with a Late Paleozoic-Early Mesozoic South China Ocean.
文摘Ultrasonic imaging is becoming the most popular medical imaging modality,owing to the low price per examination and its safety.However,blood is a poor scatterer of ultrasound waves at clinical diagnostic transmit frequencies.For perfusion imaging,markers have been designed to enhance the contrast in B-mode imaging.These so-called ultrasound contrast agents consist of microscopically small gas bubbles encapsulated in biodegradable shells.In this review,the physical principles of ultrasound contrast agent microbubble behavior and their adjustment for drug delivery including sonoporation are described.Furthermore,an outline of clinical imaging applications of contrast-enhanced ultrasound is given.It is a challenging task to quantify and predict which bubble phenomenon occurs under which acoustic condition,and how these phenomena may be utilized in ultrasonic imaging.Aided by high-speed photography,our improved understanding of encapsulated microbubble behavior will lead to more sophisticated detection and delivery techniques.More sophisticated methods use quantitative approaches to measure the amount and the time course of bolus or reperfusion curves,and have shown great promise in revealing effective tumor responses to anti-angiogenic drugs in humans before tumor shrinkage occurs.These are beginning to be accepted into clinical practice.In the long term,targeted microbubbles for molecular imaging and eventually for directed anti-tumor therapy are expected to be tested.
基金supported by Inserm(to SV,LFF,CT,JV,SB,SS,SC)by the Labex IRON(ANR-11-LABX-18-01:to all authors).
文摘To date there is no treatment able to stop or slow down the loss of dopaminergic neurons that characterizes Parkinson’s disease.It was recently observed in a rodent model of Alzheimer’s disease that the interaction between the α7 subtype of nicotinic acetylcholine receptor(α7-nAChR)and sigma-1 receptor(σ1-R)could exert neuroprotective effects through the modulation of neuroinflammation which is one of the key components of the pathophysiology of Parkinson’s disease.In this context,the aim of the present study was to assess the effects of the concomitant administration of N-(3R)-1-azabicyclo[2.2.2]oct-3-yl-furo[2,3-c]pyridine-5-carboxamide(PHA)543613 as an α7-nAChR agonist and 2-(4-morpholinethyl)1-phenylcyclohexanecarboxylate(PRE)-084 as aσ1-R agonist in a well-characterized 6-hydroxydopamine rat model of Parkinson’s disease.The animals received either vehicle separately or the dual therapy PHA/PRE once a day until day 14 postlesion.Although no effect was noticed in the amphetamine-induced rotation test,our data has shown that the PHA/PRE treatment induced partial protection of the dopaminergic neurons(15-20%),assessed by the dopamine transporter density in the striatum and immunoreactive tyrosine hydroxylase in the substantia nigra.Furthermore,this dual therapy reduced the degree of glial activation consecutive to the 6-hydroxydopamine lesion,i.e,the 18 kDa translocation protein density and glial fibrillary acidic protein staining in the striatum,and the CD11b and glial fibrillary acidic protein staining in the substantia nigra.Hence,this study reports for the first time that concomitant activation of α7-nAChR andσ1-R can provide a partial recovery of the nigro-striatal dopaminergic neurons through the modulation of microglial activation.The study was approved by the Regional Ethics Committee(CEEA Val de Loire n°19)validated this protocol(Authorization N°00434.02)on May 15,2014.
文摘Chinese East Tianshan is a key area for understanding the Paleozoic accretion of the southern Central Asian Orogenic Belt. A first accretion-collision stage, before the Visean, developed the Eo-Tianshan range, which exhibits north-verging structures. The geodynamic evolution included： i） Ordovician-Early Devonian southward subduction of a Central Tianshan ocean beneath a Central Tianshan arc; ii） Devonian oceanic closure and collision between Central Tianshan arc and Iqli-North Tianshan block, along the Central Tianshan Suture Zone; iii） Late Devonian-earliest Carboniferous closure of a South Tianshan back-arc basin, and subsequent Central Tianshan-Tarim active margin colli- sion along the South Tianshan Suture Zone. A second stage involved： i） Late Devonian-Carboniferous south- ward subduction of North Tianshan ocean beneath the Eo-Tianshan active margin （Yili-North Tianshan arc）;
