Ischemia reperfusion injury is a major obstacle in liver resection and liver transplantation surgery.Understanding the mechanisms of liver ischemia reperfusion injury(IRI) and developing strategies to counteract this ...Ischemia reperfusion injury is a major obstacle in liver resection and liver transplantation surgery.Understanding the mechanisms of liver ischemia reperfusion injury(IRI) and developing strategies to counteract this injury will therefore reduce acute complications in hepatic resection and transplantation,as well as expanding the potential pool of usable donor grafts.The initial liver injury is initiated by reactive oxygen species which cause direct cellular injury and also activate a cascade of molecular mediators leading to microvascular changes,increased apoptosis and acute inflammatory changes with increased hepatocyte necrosis.Some adaptive pathways are activated during reperfusion that reduce the reperfusion injury.IRI involves a complex interplay between neutrophils,natural killer T-cells cells,CD4+ T cell subtypes,cytokines,nitric oxide synthases,haem oxygenase-1,survival kinases such as the signal transducer and activator of transcription,Phosphatidylinositol 3-kinases/Akt and nuclear factor κβ pathways.Transgenic animals,particularly genetic knockout models,have become a powerful tool at elucidating mechanisms of liver ischaemia reperfusion injury and are complementary to pharmacological studies.Targeted disruption of the protein at the genetic level is more specific and maintained than pharmacological inhibitors or stimulants of the same protein.This article reviews the evidence from knockout models of liver IRI about the cellular and molecular mechanisms underlying liver IRI.展开更多
The Early Cretaceous Hohhot metamorphic core complex （mcc） of the Daqing Shan （Mtns.） of central Inner Mongolia is among the best exposed and most spectacular of the spatially isolated mcc＇s that developed within...The Early Cretaceous Hohhot metamorphic core complex （mcc） of the Daqing Shan （Mtns.） of central Inner Mongolia is among the best exposed and most spectacular of the spatially isolated mcc＇s that developed within the northern edge of the North China ＂craton＂. All of these mcc＇s were formed within the basement of a Late Paleozoic Andean-style arc and across older Mesozoic fold-and-thrust belts of variable age and tectonic vergence. The master Hohhot detachment fault roots southwards within the southem margin of the Daqing Shan for an along-strike distance of at least 120 km. Its geometry in the range to the north is complicated by interference patterns between （1） primary, large-scale NW-SE-trend- ing convex and concave fault corrugations and （2） secondary ENE-WSW-trending antiforms and syn- forms that folded the detachment in its late kinematic history. As in the Whipple Mtns. of California, the Hohhot master detachment is not of the Wernicke （1981） simple rooted type; instead, it was spawned from a mid-crustal shear zone, the top of which is preserved as a mylonitic front within Carboniferous metasedimentary rocks in its exhumed lower plate. 4~Ar-39Ar dating of siliceous volcanic rocks in basal sections of now isolated supradetachment basins suggest that crustal extension began at ca. 127 Ma, although lower-plate mylonitic rocks were not exposed to erosion until after ca. 119 Ma. Essentially synchronous cooling of bornblende, biotite, and muscovite in footwall mylonitic gneisses indicates very rapid exhumation and at ca. 122--120 Ma. Contrary to several recent reports, the master detachment clearly cuts across and dismembers older, north-directed thrust sheets of the Daqing Shah foreland fold-and-thrust belt. Folded and thrust-faulted basalts within its foredeep strata are as young as 132.6 ± 2.4 Ma, thus defining within 5--6 Ma the regional tectonic transition between crustal contraction and profound crustal extension.展开更多
As one of the largest Phanerozoic orogens in the world,the Central Asian Orogenic Belt(CAOB)is a natural laboratory for studies of continental dynamics and metallogenesis.This paper summarizes the research progresses ...As one of the largest Phanerozoic orogens in the world,the Central Asian Orogenic Belt(CAOB)is a natural laboratory for studies of continental dynamics and metallogenesis.This paper summarizes the research progresses of the accretionary processes and metallogenesis of the CAOB since the Peopled Republic of China was founded,and puts forward the prospect for future research.During the early period(1950s-1970s),several geological theories were applied to explain the geological evolution of Central Asia.In the early period of China's reform and opening-up,the plate tectonics theory was applied to explain the evolution of the northern Xinjiang and Xingmeng regions,and the opinion of subduction-collision between Siberian Kazakhstan and China-North Korea-Tarim plates was proposed.The idea of the Solonker-Yanbian suture zone was established.In the 1990s,the study of the CAOB entered a period of rapid development.One school of scholars including geologists from the former Soviet Union proposed a multi-block collision model for the assemblage of the CAOB.In contrast,another school of scholars,led by a Turkish geologist,Celal Sengor,proposed that the Altaids was formed through the growth and strike-slip duplicates of a single island arc,and pointed out that the Altaids is a special type of collisional orogen.During this period,Chinese geologists carried out a lot of pioneering researches on ophiolites and high-pressure metamorphic rocks in northern China,and confirmed the main suture zones accordingly.In 1999,the concept of"Central Asian metallogenic domain"was proposed,and it became one of the three major metallogenic domains in the world.Since the 21st century,given the importance for understanding continental accretion and metallogenic mechanism,the CAOB has become the international academic forefront.China has laid out a series of scientific research projects in Central Asia.A large number of important scientific research achievements have been spawned,including the tectonic attribution of micro-continents,timing and t展开更多
Sucrose is the principal product of photosynthesis used for the distribution of assimilated carbon in plants. Transport mechanisms and efficiency influence photosynthetic productivity by relieving product inhibition a...Sucrose is the principal product of photosynthesis used for the distribution of assimilated carbon in plants. Transport mechanisms and efficiency influence photosynthetic productivity by relieving product inhibition and contribute to plant vigor by controlling source/sink relationships and biomass partitioning. Sucrose is synthesized in the cytoplasm and may move cell to cell through plasmodesmata or may cross membranes to be compartmentalized or exported to the apoplasm for uptake into adjacent cells. As a relatively large polar compound, sucrose requires proteins to facilitate efficient membrane transport. Transport across the tonoplast by facilitated diffusion, antiport with protons, and symport with protons have been proposed; for transport across plasma membranes, symport with protons and a mechanism resembling facilitated diffusion are evident. Despite decades of research, only symport with protons is well established at the molecular level. This review aims to integrate recent and older studies on sucrose flux across membranes with principles of whole-plant carbon partitioning.展开更多
目的探讨骨质疏松性骨折人群的骨密度与跌倒风险、体质量指数(body mass index,BMI)、肌力、体脂含量的相关性。方法通过对4 632例社区45岁以上绝经后女性的问卷调研及骨密度筛查,筛查出既往有脆性骨折史的骨质疏松性骨折人群。测定骨...目的探讨骨质疏松性骨折人群的骨密度与跌倒风险、体质量指数(body mass index,BMI)、肌力、体脂含量的相关性。方法通过对4 632例社区45岁以上绝经后女性的问卷调研及骨密度筛查,筛查出既往有脆性骨折史的骨质疏松性骨折人群。测定骨质疏松性骨折人群的骨密度、身高、体质量、跌倒风险、肌力和腹部脂肪含量。采用Spearman检验分析跌倒指数、体脂含量、年龄、身高、体质量、BMI与骨密度(bone mass density,BMD)之间的相关性。BMD校正年龄、身高、体质量、BMI、体脂含量,采用ANCOVA分析跌倒指数对BMD的影响;校正年龄、身高、体质量、BMI、跌倒指数,分析体脂含量对BMD的影响。结果对筛查出的839例骨质疏松性骨折患者的BMD、BMI、跌倒风险、腹部体脂含量、肌力等相关性分析结果显示,骨质疏松性骨折人群BMI、跌倒指数、肌力与BMD均显著相关(BMI r=0.161,跌倒指数r=0.238,肌力r=0.198,P均<0.001)。BMI、肌力、跌倒风险与BMD呈正相关;校正年龄、身高、体质量、BMI等因素,采用ANCOVA分析跌倒指数与BMD无显著相关(F=1.011,P>0.05)。结论跌倒风险和低BMD为骨折的主要危险因素。本研究显示体脂含量与BMD呈显著相关性。展开更多
文摘Ischemia reperfusion injury is a major obstacle in liver resection and liver transplantation surgery.Understanding the mechanisms of liver ischemia reperfusion injury(IRI) and developing strategies to counteract this injury will therefore reduce acute complications in hepatic resection and transplantation,as well as expanding the potential pool of usable donor grafts.The initial liver injury is initiated by reactive oxygen species which cause direct cellular injury and also activate a cascade of molecular mediators leading to microvascular changes,increased apoptosis and acute inflammatory changes with increased hepatocyte necrosis.Some adaptive pathways are activated during reperfusion that reduce the reperfusion injury.IRI involves a complex interplay between neutrophils,natural killer T-cells cells,CD4+ T cell subtypes,cytokines,nitric oxide synthases,haem oxygenase-1,survival kinases such as the signal transducer and activator of transcription,Phosphatidylinositol 3-kinases/Akt and nuclear factor κβ pathways.Transgenic animals,particularly genetic knockout models,have become a powerful tool at elucidating mechanisms of liver ischaemia reperfusion injury and are complementary to pharmacological studies.Targeted disruption of the protein at the genetic level is more specific and maintained than pharmacological inhibitors or stimulants of the same protein.This article reviews the evidence from knockout models of liver IRI about the cellular and molecular mechanisms underlying liver IRI.
基金sponsored by National Science Foundation grants EAR-9627909 and EAR-9903012 to Davisa China National Natural Sciences Foundation grant to Zheng+1 种基金a Louisiana State University research grant to DarbyRadiometric dating was done by George Gehrels of the University of Arizona(U-Pb) and by Terry Spell of the Nevada Isotope Geochronology Laboratory (Ar/Ar,funded in part by NSF grant EPS-9720162)
文摘The Early Cretaceous Hohhot metamorphic core complex （mcc） of the Daqing Shan （Mtns.） of central Inner Mongolia is among the best exposed and most spectacular of the spatially isolated mcc＇s that developed within the northern edge of the North China ＂craton＂. All of these mcc＇s were formed within the basement of a Late Paleozoic Andean-style arc and across older Mesozoic fold-and-thrust belts of variable age and tectonic vergence. The master Hohhot detachment fault roots southwards within the southem margin of the Daqing Shan for an along-strike distance of at least 120 km. Its geometry in the range to the north is complicated by interference patterns between （1） primary, large-scale NW-SE-trend- ing convex and concave fault corrugations and （2） secondary ENE-WSW-trending antiforms and syn- forms that folded the detachment in its late kinematic history. As in the Whipple Mtns. of California, the Hohhot master detachment is not of the Wernicke （1981） simple rooted type; instead, it was spawned from a mid-crustal shear zone, the top of which is preserved as a mylonitic front within Carboniferous metasedimentary rocks in its exhumed lower plate. 4~Ar-39Ar dating of siliceous volcanic rocks in basal sections of now isolated supradetachment basins suggest that crustal extension began at ca. 127 Ma, although lower-plate mylonitic rocks were not exposed to erosion until after ca. 119 Ma. Essentially synchronous cooling of bornblende, biotite, and muscovite in footwall mylonitic gneisses indicates very rapid exhumation and at ca. 122--120 Ma. Contrary to several recent reports, the master detachment clearly cuts across and dismembers older, north-directed thrust sheets of the Daqing Shah foreland fold-and-thrust belt. Folded and thrust-faulted basalts within its foredeep strata are as young as 132.6 ± 2.4 Ma, thus defining within 5--6 Ma the regional tectonic transition between crustal contraction and profound crustal extension.
基金supported by the National Key R & D Program of China (Grant No. 2017YFC0601201)the National Natural Science Foundation of China (Grant Nos. 41888101, 41730210, 41672219)the IGCP662 Project
文摘As one of the largest Phanerozoic orogens in the world,the Central Asian Orogenic Belt(CAOB)is a natural laboratory for studies of continental dynamics and metallogenesis.This paper summarizes the research progresses of the accretionary processes and metallogenesis of the CAOB since the Peopled Republic of China was founded,and puts forward the prospect for future research.During the early period(1950s-1970s),several geological theories were applied to explain the geological evolution of Central Asia.In the early period of China's reform and opening-up,the plate tectonics theory was applied to explain the evolution of the northern Xinjiang and Xingmeng regions,and the opinion of subduction-collision between Siberian Kazakhstan and China-North Korea-Tarim plates was proposed.The idea of the Solonker-Yanbian suture zone was established.In the 1990s,the study of the CAOB entered a period of rapid development.One school of scholars including geologists from the former Soviet Union proposed a multi-block collision model for the assemblage of the CAOB.In contrast,another school of scholars,led by a Turkish geologist,Celal Sengor,proposed that the Altaids was formed through the growth and strike-slip duplicates of a single island arc,and pointed out that the Altaids is a special type of collisional orogen.During this period,Chinese geologists carried out a lot of pioneering researches on ophiolites and high-pressure metamorphic rocks in northern China,and confirmed the main suture zones accordingly.In 1999,the concept of"Central Asian metallogenic domain"was proposed,and it became one of the three major metallogenic domains in the world.Since the 21st century,given the importance for understanding continental accretion and metallogenic mechanism,the CAOB has become the international academic forefront.China has laid out a series of scientific research projects in Central Asia.A large number of important scientific research achievements have been spawned,including the tectonic attribution of micro-continents,timing and t
文摘Sucrose is the principal product of photosynthesis used for the distribution of assimilated carbon in plants. Transport mechanisms and efficiency influence photosynthetic productivity by relieving product inhibition and contribute to plant vigor by controlling source/sink relationships and biomass partitioning. Sucrose is synthesized in the cytoplasm and may move cell to cell through plasmodesmata or may cross membranes to be compartmentalized or exported to the apoplasm for uptake into adjacent cells. As a relatively large polar compound, sucrose requires proteins to facilitate efficient membrane transport. Transport across the tonoplast by facilitated diffusion, antiport with protons, and symport with protons have been proposed; for transport across plasma membranes, symport with protons and a mechanism resembling facilitated diffusion are evident. Despite decades of research, only symport with protons is well established at the molecular level. This review aims to integrate recent and older studies on sucrose flux across membranes with principles of whole-plant carbon partitioning.
文摘目的探讨骨质疏松性骨折人群的骨密度与跌倒风险、体质量指数(body mass index,BMI)、肌力、体脂含量的相关性。方法通过对4 632例社区45岁以上绝经后女性的问卷调研及骨密度筛查,筛查出既往有脆性骨折史的骨质疏松性骨折人群。测定骨质疏松性骨折人群的骨密度、身高、体质量、跌倒风险、肌力和腹部脂肪含量。采用Spearman检验分析跌倒指数、体脂含量、年龄、身高、体质量、BMI与骨密度(bone mass density,BMD)之间的相关性。BMD校正年龄、身高、体质量、BMI、体脂含量,采用ANCOVA分析跌倒指数对BMD的影响;校正年龄、身高、体质量、BMI、跌倒指数,分析体脂含量对BMD的影响。结果对筛查出的839例骨质疏松性骨折患者的BMD、BMI、跌倒风险、腹部体脂含量、肌力等相关性分析结果显示,骨质疏松性骨折人群BMI、跌倒指数、肌力与BMD均显著相关(BMI r=0.161,跌倒指数r=0.238,肌力r=0.198,P均<0.001)。BMI、肌力、跌倒风险与BMD呈正相关;校正年龄、身高、体质量、BMI等因素,采用ANCOVA分析跌倒指数与BMD无显著相关(F=1.011,P>0.05)。结论跌倒风险和低BMD为骨折的主要危险因素。本研究显示体脂含量与BMD呈显著相关性。
