Endoscopic cryotherapy is a relatively new thermal ablative modality used for the treatment of neoplastic lesions of the esophagus. It relies on cycles of rapid cooling and thawing to induce tissue destruction with a ...Endoscopic cryotherapy is a relatively new thermal ablative modality used for the treatment of neoplastic lesions of the esophagus. It relies on cycles of rapid cooling and thawing to induce tissue destruction with a cryogen(liquid nitrogen or carbon dioxide) leading to intra and extra-cellular damage. Surgical treatment was once considered the standard therapeutic intervention for neoplastic diseases of the esophagus and is associated with considerable rates of morbidity and mortality. Several trials that evaluated cryotherapy in Barrett's esophagus(BE) associated neoplasia showed reasonable efficacy rates and safety profile. Cryotherapy has also found applications in the treatment of esophageal cancer, both for curative and palliative intent. Cryotherapy has also shown promising results as salvage therapy in cases refractory to radiofrequency ablation treatment. Cryoballoon focal ablation using liquid nitrogen is a novel mode of cryogen delivery which has been used for the treatment of BE with dysplasia and squamous cell carcinoma. Most common side effects of cryotherapy reported in the literature include mild chest discomfort, esophageal strictures and bleeding. In conclusion, cryotherapy is an effective and safe method for the treatment of esophageal neoplastic processes, ranging from early stages of low grade dysplasia to esophageal cancer.展开更多
Based on analyzing the circulation development of 100 hPa, 500 hPa, lower streamline field and the change of physical vadables, the diagnostic analysis of a turning cold wave process in northern Xinjiang from Feb. 10 ...Based on analyzing the circulation development of 100 hPa, 500 hPa, lower streamline field and the change of physical vadables, the diagnostic analysis of a turning cold wave process in northern Xinjiang from Feb. 10 -13th 2009 was carried out. The results showed that abnormality of 100 hPa polar vortex taking on stable two waves, catastrophe of 500 hPa western Siberian trough, strong cold advection and water vapor transport from Middle Asia are chief reasons of the process.展开更多
This paper is a review of studies of abrupt climate changes(ACCs) during the Holocene published during the past ten years.North Atlantic cold events are indicators of ACCs.As indicated by North Atlantic ice-rafted deb...This paper is a review of studies of abrupt climate changes(ACCs) during the Holocene published during the past ten years.North Atlantic cold events are indicators of ACCs.As indicated by North Atlantic ice-rafted debris(IRD),there were nine confirmed cold events during the Holocene,occurring at 11.1 kyr,10.3 kyr,9.4 kyr,8.1 kyr,5.9 kyr,4.2 kyr,2.8 kyr,1.4 kyr,and 0.4 kyr respectively according to most representative results from Bond et al.(1997).However,the identification of chronology has been made with some uncertainties.Considerable climatic proxy data have shown that,during the cold events,substantial climate abnormalities have occurred widely across the globe,particularly in the areas surrounding the North Atlantic.These abnormalities were in the form of high-latitude cold in the both hemispheres,expansion of the Westerlies to low latitudes,drought in the monsoon regions,recession of summer monsoons,and intensification of the winter monsoons.Studies have indicated that the four ACCs occurring in the early Holocene may be related to freshwater pulses from ice melting in the northern part of the North Atlantic,and the other five ACCs that occurred during the middle and late Holocene may be related to the decreased solar activity.展开更多
We analyze the relationships between strato- spheric polar vortex anomalies and cooling events in eastern China using isentropic reanalysis data from the European Center for Medium-Range Weather Forecasts. Daily mean ...We analyze the relationships between strato- spheric polar vortex anomalies and cooling events in eastern China using isentropic reanalysis data from the European Center for Medium-Range Weather Forecasts. Daily mean data from 2000 to 2011 are used to explore the effective stratospheric signals. First, diagnoses of the 2009/2010 winter show that after the stratospheric sudden warming （SSW） of the Atlantic-East Asian （AEA） pattern, the stratospheric high isentropic potential vorticity （IPV） center derived from the split polar vortex will move to the northeast of the Eurasian continent. The air mass, accom- panied by some southward and eastward movements and characterized by high IPV values, will be stretched verti- cally, leading to apparent reinforcements of the positive vorticity and the development of acold vortex system in the troposphere. The northerly wind on the western side of the cold vortex can transport cold air southward and down- ward, resulting in this distinct cooling process in eastern China. Secondly, the empirical orthogonal function ana- lyses of IPV anomalies on the 430 K isentropic surface during 2000-2011 winters indicate that the IPV distribution and time series of the first mode are able to represent the polar vortex variation features, which significantly influ- ence cold-air activity in eastern China, especially in the AEA-type SSW winter. When the time series increases significantly, the polar vortex will be split and the high-IPV center will move to the northeast of the Eurasian continent with downward and southward developments, inducing obvious cooling in eastern China. Moreover, all the four times SSW events of AEA pattern from 2000 to 2011 are reflected in the first time series, and after the strong polar vortex disturbances, cooling processes of different inten- sities are observed in eastern China. The cooling can sus- tain at least 1 week. For this reason, the first time series can be used as an available index of polar vortex oscillation and has the power to predict cold-air activity in winter.展开更多
文摘Endoscopic cryotherapy is a relatively new thermal ablative modality used for the treatment of neoplastic lesions of the esophagus. It relies on cycles of rapid cooling and thawing to induce tissue destruction with a cryogen(liquid nitrogen or carbon dioxide) leading to intra and extra-cellular damage. Surgical treatment was once considered the standard therapeutic intervention for neoplastic diseases of the esophagus and is associated with considerable rates of morbidity and mortality. Several trials that evaluated cryotherapy in Barrett's esophagus(BE) associated neoplasia showed reasonable efficacy rates and safety profile. Cryotherapy has also found applications in the treatment of esophageal cancer, both for curative and palliative intent. Cryotherapy has also shown promising results as salvage therapy in cases refractory to radiofrequency ablation treatment. Cryoballoon focal ablation using liquid nitrogen is a novel mode of cryogen delivery which has been used for the treatment of BE with dysplasia and squamous cell carcinoma. Most common side effects of cryotherapy reported in the literature include mild chest discomfort, esophageal strictures and bleeding. In conclusion, cryotherapy is an effective and safe method for the treatment of esophageal neoplastic processes, ranging from early stages of low grade dysplasia to esophageal cancer.
基金Supported by Forecaster Special Project of New Technique Populanzationof China Meteorological Administration(CMATG2009YB10)~~
文摘Based on analyzing the circulation development of 100 hPa, 500 hPa, lower streamline field and the change of physical vadables, the diagnostic analysis of a turning cold wave process in northern Xinjiang from Feb. 10 -13th 2009 was carried out. The results showed that abnormality of 100 hPa polar vortex taking on stable two waves, catastrophe of 500 hPa western Siberian trough, strong cold advection and water vapor transport from Middle Asia are chief reasons of the process.
基金Under the auspices of National Natural Science Foundation of China (No. 41101083,41130105)Strategic Project of Institute of Geographic Sciences and Natural Resources Research,Chinese Academy of Sciences (No. 2012ZD001)Major State Basic Research Development Program of China (No. 2010CB950104)
文摘This paper is a review of studies of abrupt climate changes(ACCs) during the Holocene published during the past ten years.North Atlantic cold events are indicators of ACCs.As indicated by North Atlantic ice-rafted debris(IRD),there were nine confirmed cold events during the Holocene,occurring at 11.1 kyr,10.3 kyr,9.4 kyr,8.1 kyr,5.9 kyr,4.2 kyr,2.8 kyr,1.4 kyr,and 0.4 kyr respectively according to most representative results from Bond et al.(1997).However,the identification of chronology has been made with some uncertainties.Considerable climatic proxy data have shown that,during the cold events,substantial climate abnormalities have occurred widely across the globe,particularly in the areas surrounding the North Atlantic.These abnormalities were in the form of high-latitude cold in the both hemispheres,expansion of the Westerlies to low latitudes,drought in the monsoon regions,recession of summer monsoons,and intensification of the winter monsoons.Studies have indicated that the four ACCs occurring in the early Holocene may be related to freshwater pulses from ice melting in the northern part of the North Atlantic,and the other five ACCs that occurred during the middle and late Holocene may be related to the decreased solar activity.
基金supported by the National Natural Science Foundation of China(41205041)Chinese Special Fund for Meteorology(GYHY201406020)+1 种基金National Basic Research Program of China(2012CB417205)LCS Open Funds for Young Scholars(2014)
文摘We analyze the relationships between strato- spheric polar vortex anomalies and cooling events in eastern China using isentropic reanalysis data from the European Center for Medium-Range Weather Forecasts. Daily mean data from 2000 to 2011 are used to explore the effective stratospheric signals. First, diagnoses of the 2009/2010 winter show that after the stratospheric sudden warming （SSW） of the Atlantic-East Asian （AEA） pattern, the stratospheric high isentropic potential vorticity （IPV） center derived from the split polar vortex will move to the northeast of the Eurasian continent. The air mass, accom- panied by some southward and eastward movements and characterized by high IPV values, will be stretched verti- cally, leading to apparent reinforcements of the positive vorticity and the development of acold vortex system in the troposphere. The northerly wind on the western side of the cold vortex can transport cold air southward and down- ward, resulting in this distinct cooling process in eastern China. Secondly, the empirical orthogonal function ana- lyses of IPV anomalies on the 430 K isentropic surface during 2000-2011 winters indicate that the IPV distribution and time series of the first mode are able to represent the polar vortex variation features, which significantly influ- ence cold-air activity in eastern China, especially in the AEA-type SSW winter. When the time series increases significantly, the polar vortex will be split and the high-IPV center will move to the northeast of the Eurasian continent with downward and southward developments, inducing obvious cooling in eastern China. Moreover, all the four times SSW events of AEA pattern from 2000 to 2011 are reflected in the first time series, and after the strong polar vortex disturbances, cooling processes of different inten- sities are observed in eastern China. The cooling can sus- tain at least 1 week. For this reason, the first time series can be used as an available index of polar vortex oscillation and has the power to predict cold-air activity in winter.
