Pancreatic cancer is an aggressive malignancy with a high recurrence rate even after curative-intent resection.Improvements in survival have not been achieved in the last 25 years thus highlighting the need for effect...Pancreatic cancer is an aggressive malignancy with a high recurrence rate even after curative-intent resection.Improvements in survival have not been achieved in the last 25 years thus highlighting the need for effective multimodal treatment strategies.The role of radiation therapy for pancreatic cancer remains ill-defined due to historical lack of a standard definition of resectability,and the use of antiquated radiation delivery techniques and chemotherapy regimens.Current level I data regarding neoadjuvant chemoradiotherapy for resectable and borderline resectable pancreatic adenocarcinoma(PDAC)are limited to 2 randomized controlled trials and several retrospective studies and suggest that it may lead to an increased likelihood of a margin-negative resection and certainly allows for improved patient selection for pancreaticoduodenectomy when compared to upfront surgery.In the adjuvant setting,data are similarly lacking but suggest that chemoradiotherapy may be beneficial for patients at high risk of locoregional recurrence.Here we review existing data regarding the role of radiation in PDAC.展开更多
We investigate the role of clouds and radiation in the general circulation of the atmosphere using a model designed for 30-day predictions.Comprehensive verifications of 30-day predictions for the 500 hPa geo- potenti...We investigate the role of clouds and radiation in the general circulation of the atmosphere using a model designed for 30-day predictions.Comprehensive verifications of 30-day predictions for the 500 hPa geo- potential height field have been carried out,using the data from ECMWF objective analyses that cover the period from May 5 to June 3,1982.We perform three model simulations,including experiments with interac- tive cloud formation,without clouds,and without radiative heating.The latter two experiments allow us to study the effects of cloud/radiation interactions and feedbacks on the predicted vertical velocity,and the meridional and zonal wind profiles,averaged over a 30-day period. We demonstrate that the Hadley circulation is maintained by the presence of clouds.The radiative cooling in the atmosphere intensifies the vertical motion in low latitudes and,to some extent,also strengthens the overall meridional circulation.The meridional winds are correctly reproduced in the model if clouds are incorporated. The zonal winds are significantly affected by clouds and radiative cooling.Without an appropriate incor- poration of these physical elements,the model results would deviate significantly from observations.The presence of clouds strengthens the westerlies in middle and high levels.In May,the northerly movement of the jet stream over eastern Asia is,in part,associated with the presence of clouds.展开更多
文摘Pancreatic cancer is an aggressive malignancy with a high recurrence rate even after curative-intent resection.Improvements in survival have not been achieved in the last 25 years thus highlighting the need for effective multimodal treatment strategies.The role of radiation therapy for pancreatic cancer remains ill-defined due to historical lack of a standard definition of resectability,and the use of antiquated radiation delivery techniques and chemotherapy regimens.Current level I data regarding neoadjuvant chemoradiotherapy for resectable and borderline resectable pancreatic adenocarcinoma(PDAC)are limited to 2 randomized controlled trials and several retrospective studies and suggest that it may lead to an increased likelihood of a margin-negative resection and certainly allows for improved patient selection for pancreaticoduodenectomy when compared to upfront surgery.In the adjuvant setting,data are similarly lacking but suggest that chemoradiotherapy may be beneficial for patients at high risk of locoregional recurrence.Here we review existing data regarding the role of radiation in PDAC.
基金This research wes supported by the Air Force Office of Scientific Grant AFOSR-87-0294.
文摘We investigate the role of clouds and radiation in the general circulation of the atmosphere using a model designed for 30-day predictions.Comprehensive verifications of 30-day predictions for the 500 hPa geo- potential height field have been carried out,using the data from ECMWF objective analyses that cover the period from May 5 to June 3,1982.We perform three model simulations,including experiments with interac- tive cloud formation,without clouds,and without radiative heating.The latter two experiments allow us to study the effects of cloud/radiation interactions and feedbacks on the predicted vertical velocity,and the meridional and zonal wind profiles,averaged over a 30-day period. We demonstrate that the Hadley circulation is maintained by the presence of clouds.The radiative cooling in the atmosphere intensifies the vertical motion in low latitudes and,to some extent,also strengthens the overall meridional circulation.The meridional winds are correctly reproduced in the model if clouds are incorporated. The zonal winds are significantly affected by clouds and radiative cooling.Without an appropriate incor- poration of these physical elements,the model results would deviate significantly from observations.The presence of clouds strengthens the westerlies in middle and high levels.In May,the northerly movement of the jet stream over eastern Asia is,in part,associated with the presence of clouds.
