Exercise stress echocardiography(ESE)is a widely used diagnostic test in cardiology departments.ESE is mainly used to study patients with coronary artery disease;however,it has increasingly been used in other clinical...Exercise stress echocardiography(ESE)is a widely used diagnostic test in cardiology departments.ESE is mainly used to study patients with coronary artery disease;however,it has increasingly been used in other clinical scenarios including valve pathology,congenital heart disease,hypertrophic and dilated cardiomyopathies,athlete evaluations,diastolic function evaluation,and pulmonary circulation study.In our laboratories,we use an established methodology in which cardiac function is evaluated while exercising on a treadmill.After completing the exercise regimen,patients remain in a standing position or lie down on the left lateral decubitus,depending on the clinical questions to be answered for further evaluation.This method increases the quality and quantity of information obtained.Here,we present the various methods of exercise stress echocardiography and our experience in many clinical arenas in detail.We also present alternatives to ESE that may be used and their advantages and disadvantages.We review recent advances in ESE and future directions for this established method in the study of cardiac patients and underline the advantage of using a diagnostic tool that is radiation-free.展开更多
Iron formations are valuable archives of sedimentary conditions and post-depositional events.However,geochemical proxies commonly used to determine genetic characteristics can be variably modified during metamorphism ...Iron formations are valuable archives of sedimentary conditions and post-depositional events.However,geochemical proxies commonly used to determine genetic characteristics can be variably modified during metamorphism and deformation,hampering their use as records of regional geological events.This work focuses on strongly reworked magnetite-quartz-rich rocks from the São Josédo Campestre Massif,one of the oldest fragments of preserved crust in South America.The genetic classification of these magnetite-quartz-rich rocks is not straightforward because primary assemblages and textures were variably modified by granulite facies metamorphism during a regional Paleoproterozoic migmatization event.To address genetic ambiguities,we analyzed their magnetite and pyroxene chemistry,wholerock geochemistry,and Sm-Nd isotopes.Magnetite chemistry indicates that pyroxene-poor iron formations(Type B)are low in trace elements such as Ti,Al,V,and Mn,suggesting a chemical similarity to iron formations elsewhere.In contrast,magnetites from pyroxene-enriched Type A iron formations are rich in trace elements and more akin to magnetite crystallized from higher temperature systems,such as skarn and IOCG.The^(147)Sm/^(144)Nd of these rocks show substantial variation even at the outcrop scale,indicating a locally-controlled,highly heterogeneous mixture of Archean,Paleoproterozoic,and Neoproterozoic sources.Therefore,our geochemical tools point out to heterogenous signatures of these magnetitequartz rocks and proxies compatible with both low and high-temperature conditions and age of deposition spanning sources from the Archean to the Neoproterozoic.We interpret that the studied São Josédo Campestre magnetite-quartz rocks represent Archean iron formations with original magnetite chemistry and isotopic signatures variably modified by metamorphism and by at least one deformation-related hydrothermal event.These results contrast with similar examples from China and Greenland where iron formations either preserved the magnetite chemistry or the primary isotopic signatures.Our study indicates that metamorphism can selectively affect chemical proxies used to study iron formations and undermine the genetic classification of iron ores.Thus,these proxies should be carefully applied in the interpretation of syn-depositional environments of polydeformed belts.展开更多
文摘Exercise stress echocardiography(ESE)is a widely used diagnostic test in cardiology departments.ESE is mainly used to study patients with coronary artery disease;however,it has increasingly been used in other clinical scenarios including valve pathology,congenital heart disease,hypertrophic and dilated cardiomyopathies,athlete evaluations,diastolic function evaluation,and pulmonary circulation study.In our laboratories,we use an established methodology in which cardiac function is evaluated while exercising on a treadmill.After completing the exercise regimen,patients remain in a standing position or lie down on the left lateral decubitus,depending on the clinical questions to be answered for further evaluation.This method increases the quality and quantity of information obtained.Here,we present the various methods of exercise stress echocardiography and our experience in many clinical arenas in detail.We also present alternatives to ESE that may be used and their advantages and disadvantages.We review recent advances in ESE and future directions for this established method in the study of cardiac patients and underline the advantage of using a diagnostic tool that is radiation-free.
基金supported by the National Council for the Improvement of Higher Education(CAPES)the Brazilian Council for Research and Technological Development(CNPQ)。
文摘Iron formations are valuable archives of sedimentary conditions and post-depositional events.However,geochemical proxies commonly used to determine genetic characteristics can be variably modified during metamorphism and deformation,hampering their use as records of regional geological events.This work focuses on strongly reworked magnetite-quartz-rich rocks from the São Josédo Campestre Massif,one of the oldest fragments of preserved crust in South America.The genetic classification of these magnetite-quartz-rich rocks is not straightforward because primary assemblages and textures were variably modified by granulite facies metamorphism during a regional Paleoproterozoic migmatization event.To address genetic ambiguities,we analyzed their magnetite and pyroxene chemistry,wholerock geochemistry,and Sm-Nd isotopes.Magnetite chemistry indicates that pyroxene-poor iron formations(Type B)are low in trace elements such as Ti,Al,V,and Mn,suggesting a chemical similarity to iron formations elsewhere.In contrast,magnetites from pyroxene-enriched Type A iron formations are rich in trace elements and more akin to magnetite crystallized from higher temperature systems,such as skarn and IOCG.The^(147)Sm/^(144)Nd of these rocks show substantial variation even at the outcrop scale,indicating a locally-controlled,highly heterogeneous mixture of Archean,Paleoproterozoic,and Neoproterozoic sources.Therefore,our geochemical tools point out to heterogenous signatures of these magnetitequartz rocks and proxies compatible with both low and high-temperature conditions and age of deposition spanning sources from the Archean to the Neoproterozoic.We interpret that the studied São Josédo Campestre magnetite-quartz rocks represent Archean iron formations with original magnetite chemistry and isotopic signatures variably modified by metamorphism and by at least one deformation-related hydrothermal event.These results contrast with similar examples from China and Greenland where iron formations either preserved the magnetite chemistry or the primary isotopic signatures.Our study indicates that metamorphism can selectively affect chemical proxies used to study iron formations and undermine the genetic classification of iron ores.Thus,these proxies should be carefully applied in the interpretation of syn-depositional environments of polydeformed belts.
