期刊文献+
共找到814篇文章
< 1 2 41 >
每页显示 20 50 100
Intensity modulated radiation therapy with simultaneous integrated boost based dose escalation on neoadjuvant chemoradiation therapy for locally advanced distal esophageal adenocarcinoma 被引量:1
1
作者 Ming Zeng Fernando N Aguila +4 位作者 Taral Patel Mark Knapp XueQiang Zhu XiLin Chen Phillip D Price 《World Journal of Gastrointestinal Oncology》 SCIE CAS 2016年第5期474-480,共7页
AIM:To evaluate impact of radiation therapy dose escalation through intensity modulated radiation therapy with simultaneous integrated boost(IMRT-SIB).METHODS:We retrospectively reviewed the patients who underwent fou... AIM:To evaluate impact of radiation therapy dose escalation through intensity modulated radiation therapy with simultaneous integrated boost(IMRT-SIB).METHODS:We retrospectively reviewed the patients who underwent four-dimensional-based IMRT-SIBbased neoadjuvant chemoradiation protocol.During the concurrent chemoradiation therapy,radiation therapy was through IMRT-SIB delivered in 28 consecutive daily fractions with total radiation doses of 56 Gy to tumor and 5040 Gy dose-painted to clinical tumor volume,with a regimen at the discretion of the treating medical oncologist.This was followed by surgical tumor resection.We analyzed pathological completion response(p CR) rates its relationship with overall survival and event-freesurvival.RESULTS:Seventeen patients underwent dose escalation with the IMRT-SIB protocol between 2007 and 2014 and their records were available for analysis.Among the IMRT-SIB-treated patients,the toxicity appeared mild,the most common side effects were grade 1-3 esophagitis(46%) and pneumonitis(11.7%).There were no cardiac events.The Ro resection rate was 94%(n = 16),the p CR rate was 47%(n = 8),and the postoperative morbidity was zero.There was one mediastinal failure found,one patient had local failure at the anastomosis site,and the majority of failures were distant in the lung or bone.The 3-year diseasefree survival and overall survival rates were 41%(n = 7) and 53%(n = 9),respectively.CONCLUSION:The dose escalation through IMRT-SIB in the chemoradiation regimen seems responsible for down-staging the distal esophageal with well-tolerated complications. 展开更多
关键词 Intensity modulated radiation therapy ESOPHAGEAL ADENOCARCINOMA Simultaneous integrated boost NEOADJUVANT CHEMORADIatION dose ESCALatION Resection rate
下载PDF
To Optimize the Therapeutic Dose and Time Window of Picroside II in Cerebral Ischemic Injury in Rats by Orthogonal Test 被引量:1
2
作者 Hui Huang Li Sun +3 位作者 Ling Wang Lei Fang Li Zhao Yan Li 《Neuroscience & Medicine》 2013年第3期166-171,共6页
The paper aims to optimize the therapeutic dose and time window of picroside II by orthogonal test in cerebral ischemic injury in rats. The forebrain ischemia models were established by bilateral common carotid artery... The paper aims to optimize the therapeutic dose and time window of picroside II by orthogonal test in cerebral ischemic injury in rats. The forebrain ischemia models were established by bilateral common carotid artery occlusion (BCCAO) methods. The successful models were randomly divided into sixteen groups according to orthogonal experimental design and treated by injecting picroside II intraperitonenally at different ischemic time with different dose. The concentrations of neuron-specific enolase (NSE), neuroglial marker protein S100B and myelin basic protein (MBP) in serum were determined by enzyme linked immunosorbent assay to evaluate the therapeutic effect of picroside II in cerebral ischemic injury. The results indicated that best therapeutic time window and dose of picroside II in cerebral ischemic injury were ischemia 1.5 h with 20 mg/kg body weight according to the concentrations of NSE, S100B and MBP in serum. It is concluded that according to the principle of lowest therapeutic dose with longest time window, the optimized therapeutic dose and time window are injecting picroside II intraperitonenally with 20 mg/kg body weight at ischemia 1.5 h in cerebral ischemic injury in rats. 展开更多
关键词 Picroside II CEREBRAL Ischemia theRAPEUTIC dose time WINDOW RatS
下载PDF
The anti-inflammatory effect of picroside II and the optimizing of therapeutic dose and time window in cerebral ischemic injury in rats 被引量:1
3
作者 Li Zhao Xiaodan Li +3 位作者 Tingting Wang Yunliang Guo Fangfang Pang Cuicui Chang 《Modern Research in Inflammation》 2013年第3期46-53,共8页
The aim is to optimize the anti-inflammatory effect and the therapeutic dose and time window of picrosede II by orthogonal test in cerebral ischemic injury in rats. The forebrain ischemia models were established by bi... The aim is to optimize the anti-inflammatory effect and the therapeutic dose and time window of picrosede II by orthogonal test in cerebral ischemic injury in rats. The forebrain ischemia models were established by bilateral common carotid artery occlusion (BCCAO) methods in 30 Wistar rats. The successful models were randomly divided into sixteen groups according to orthogonal experimental design and treated by injecting picroside II intraperitoneally at different ischemic time with different dose. The concentrations of aquaporins 4 (AQP4), matrix metalloproteinases9 (MMP9) and cyclooxygenase 2 (COX2) in serum and brain tissue were determined by enzyme linked immunosorbent assay to evaluate the therapeutic effect of picroside II in cerebral ischemic injury. The best therapeutic time window and dose of picroside II in cerebral ischemic injury were 1) ischemia 2.0 h with 20 mg/kg and 1.5 h with 20 mg/kg body weight according to the concentration of AQP4 in serum and brain tissue;2) ischemia 1.5 h with 20 mg/kg and ischemia 2.0 h with 20 mg/kg according to the concentrations of MMP9 in serum and brain tissue;and 3) ischemia 1.5 h with 10 mg/kg and ischemia 1.5 h with 20 mg/kg according to the concentrations of COX2 in serum and brain tissue respectively. According to the principle of the lowest therapeutic dose with the longest time window, the optimized therapeutic dose and time window were injecting picroside II intraperitoneally with 10 - 20 mg/kg body weight at ischemia 1.5 - 2.0 h in cerebral ischemic injury. 展开更多
关键词 Picroside II theRAPEUTIC dose time WINDOW CEREBRAL Ischemia AQP4 MMP9 COX-2 RatS
下载PDF
Time and Dose-related Effects of the Pyrethroid Fluvalinate on Haemolymph Carbohydrates and Gut Lipids of Honeybees,Following in vivo Injection of very Low Doses 被引量:1
4
作者 K.M'DIAYE M.BOUNIAS 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 1993年第2期145-153,共9页
The injection to emerging adult workerbees with fluvalinate doses ranging from 1 femtomol to 1 nanomol per individual resulted in a reduction of haemolymph carbohydrate concentrations, particularly at the lowest dose ... The injection to emerging adult workerbees with fluvalinate doses ranging from 1 femtomol to 1 nanomol per individual resulted in a reduction of haemolymph carbohydrate concentrations, particularly at the lowest dose 1 hour after injections. At the same time, a large increase was observed for triacylglycerols and to a much lesser extent for steroids and phospholipids with 0.1 picomol per bee. By contrast, fatty acids, steroids and triacylglycerols exhibited a depress at the higher dose. Most responses were thus biphasic, showing that much attention should be paid to the effects of very low doses of pesticide. 展开更多
关键词 time and dose-related Effects of the Pyrethroid Fluvalinate on Haemolymph Carbohydrates and Gut Lipids of Honeybees Following in vivo Injection of very Low doses very
下载PDF
How Safe Are Reduced Doses per Fraction in Target Volumes of 2<sup>nd</sup>to 4<sup>th</sup>Order in the Simultaneous Integrated Boost Irradiation Technique in Head and Neck Carcinoma Patients?
5
作者 A. Buchali C. Schroeder +3 位作者 C. Boerrnert I. Maekelburg W. Huhnt A. Franzen 《Journal of Cancer Therapy》 2015年第2期213-221,共9页
Aim: The simultaneous irradiation of target volumes of different total dose levels using intensity modulated radiotherapy leads to reduced doses per fraction and longer treatment times in target volumes of 2nd?to 4th?... Aim: The simultaneous irradiation of target volumes of different total dose levels using intensity modulated radiotherapy leads to reduced doses per fraction and longer treatment times in target volumes of 2nd?to 4th?order. Does the thereby caused reduced biological effectiveness induce an increased recurrence risk? The current work deals with the problem of recurrences of patients with head and neck carcinomas treated either with an intensitiy (IMRT) or with a volumetric modulated (VMAT) irradiation technique. Methods: From October 2002 to September 2014, 699 patients with carcinomas of the head and neck were irradiated using IMRT or VMAT. The median follow up of the patients was 21.9 months (2 to 145 months). Primary tumor regions (1st?order target volume) of 565 patients were treated with doses per fraction of 2 Gy. Accordingly, further 133 target volumes of the primary tumor received reduced doses per fraction. In 1 patient, the lymphatic drainage was treated solely without irradiation of the primary region. For the lympatic drainage, 854 1st?order target volumes were treated with a dose per fraction of 2 Gy. Reduced doses per fraction were applied to further 1780 target volumes. Results: 54 of 699 patients developed a recurrence in the primary tumor region after radio-(chemo) therapy, 4 patients developed a recurrence of the primary tumor and a unilateral recurrence of the lymphatic drainage, 2 patients a recurrence of the primary tumor and a bilateral lymph node recurrence. 18 patients showed an isolated unilateral recurrence and additionally 2 patients a bilateral recurrence of the lymphatic drainage. 619 patients stayed recurrence free. In primary tumor regions, receiving a dose per fraction of 2 Gy 55 patients (9.7%) developed a recurrence, whereas in target volumes receiving a reduced dose per fraction 5 patients (3.8%) developed a recurrence (p < 0.001). In lympatic drainage target volumes receiving a dose per fraction of 2 Gy, 25 target volumes (2.9%) developed a recurrence, whereas in target volumes receiving a reduced dose per fraction, 5 patients (0.3%) developed a recurrence (p = 0.001). Conclusion: The recurrence risk in target volumes of 2nd?to 4th?order was not increased due to reduced doses per fraction deposited by means of a simultaneous integrated boost technique. Therefore, the simultaneous irradiation of target volumes with different dose levels is safely applicable within one treatment plan. 展开更多
关键词 Head and NECK Carcinoma Simultaneous Integrated boost TECHNIQUE dose Painting dose PER FRACTION Recurrence Risk
下载PDF
The Neuroprotective Effect of Picroside II and Its Best Therapeutic Dose and Time Window in Cerebral Ischemic Injury in Rats
6
作者 Li Zhao Xiaodan Li +2 位作者 Yunliang Guo Cuicui Chang Fangfang Pang 《Journal of Behavioral and Brain Science》 2013年第5期385-392,共8页
Objective: To study the neuroprotective effect of picrosede II and explore the best therapeutic dose and time window according to orthogonal design in cerebral ischemic injury in rats. Methods: The forebrain ischemia ... Objective: To study the neuroprotective effect of picrosede II and explore the best therapeutic dose and time window according to orthogonal design in cerebral ischemic injury in rats. Methods: The forebrain ischemia rat models were established by bilateral common carotid artery occlusion (BCCAO) method. The successful models were randomly grouped according to orthogonal experimental design and treated by injecting picroside II intraperitoneally at different ischemic time with different doses. The contents of neuron-specific enolase (NSE), neuroglial marker protein S100B and myelin basic protein (MBP) in serum and brain tissue were determined by enzyme linked immunosorbent assay (ELISA) to evaluate the therapeutic effect of picroside II in cerebral ischemic injury. Results: The best therapeutic time window and dose of picroside II in cerebral ischemic injury may be 1) ischemia 1.5 h with 20 mg/kg and ischemia 1.5 h with 10 mg/kg body weight according to the content of NSE in serum and brain tissue respectively, 2) ischemia 1.5 h with 20 mg/kg according to the content of S100B in both serum and brain tissue, and 3) ischemia 1.5 h with 20 mg/kg and ischemia 1.5 h with 10 mg/kg according to the content of MBP in serum and brain tissue respectively. Conclusion: Based on the principle of the minimization of therapeutic drug dose and maximization of therapeutic time window, the optimal composition of the therapeutic dose and time window of picroside II in treating cerebral ischemic injury should be achieved by injecting picroside II intraperitoneally with 10-20 mg/kg body weight at ischemia 1.5 h in cerebral ischemic injury in rats. 展开更多
关键词 Picroside II theRAPEUTIC dose time WINDOW CEREBRAL Ischemia NSE S100B MBP RatS
下载PDF
Concurrent chemotherapy and reduced - dose cranial spinal irradiation followed by conformal posterior fossa tumor bed boost for average - risk medulloblastoma: efficacy and patterns of failure 被引量:2
7
作者 Douglas JG Barker JL +1 位作者 Ellenbogen RG Geyer JR 《中国神经肿瘤杂志》 2004年第1期46-46,共1页
PURPOSE:To review the efficacy and patterns of failure in average-risk medulloblastoma patients treated withconcurrent chemotherapy and reduced-dose cranial spinal irradiation and a conformal tumor bed boost.METH-ODS ... PURPOSE:To review the efficacy and patterns of failure in average-risk medulloblastoma patients treated withconcurrent chemotherapy and reduced-dose cranial spinal irradiation and a conformal tumor bed boost.METH-ODS AND MATERIALS:Thirty-three patients with average risk(defined as<==1.5 cm(2)of residual tumorafter resection,age>3 years,and no involvement of the cerebrospinal fluid or spine)medulloblastoma werediagnosed at our institution between January 1994 and December 2001.They were enrolled in an institutional 展开更多
关键词 dose cranial spinal irradiation followed by conformal posterior fossa tumor bed boost for average efficacy and patterns of failure risk medulloblastoma Concurrent chemotherapy and reduced
下载PDF
顾及地球物理效应的GNSS高程时间序列AdaBoost预测和插值方法
8
作者 鲁铁定 李祯 《测绘学报》 EI CSCD 北大核心 2024年第6期1077-1085,共9页
传统的GNSS高程时间序列预测和插值方法仅考虑时间变量,具有明显的局限性。本文顾及地球物理效应的影响,通过温度、大气压强、极移等数据和GNSS高程时间序列数据构建回归问题,使用自适应提升(AdaBoost)算法建模。为了验证模型的预测和... 传统的GNSS高程时间序列预测和插值方法仅考虑时间变量,具有明显的局限性。本文顾及地球物理效应的影响,通过温度、大气压强、极移等数据和GNSS高程时间序列数据构建回归问题,使用自适应提升(AdaBoost)算法建模。为了验证模型的预测和插值性能,试验选取4个GNSS站的高程时间序列进行分析。建模试验表明,相较于Prophet模型,AdaBoost模型的拟合精度提升了约35%;预测结果表明,在12个月的预测周期内,AdaBoost模型在4个GNSS站的MAE值为4.0~4.5 mm,RMSE值约为5.0~6.0 mm;插值试验表明,相较于三次样条插值方法,AdaBoost插值模型的精度约提升了15%~28%。预测和插值试验表明,顾及地球物理效应的AdaBoost模型可以应用于GNSS高程时间序列预测与插值。 展开更多
关键词 GNSS高程时间序列 地球物理效应 预测 插值 自适应提升算法
下载PDF
基于XGBoost和TCN-Attention的棉花价格多影响因素选择及预测 被引量:3
9
作者 王世杰 王兴芬 岳婷 《计算机系统应用》 2023年第10期10-21,共12页
棉花价格受多种因素影响而复杂多变,通过选择合适的数据特征和预测模型可提高棉花价格预测精度.本文以棉花日现货价格数据为研究目标,采集了供需关系、国际市场、宏观经济、产业链这4个方面的9项影响因素作为特征,使用极限梯度提升(XGBo... 棉花价格受多种因素影响而复杂多变,通过选择合适的数据特征和预测模型可提高棉花价格预测精度.本文以棉花日现货价格数据为研究目标,采集了供需关系、国际市场、宏观经济、产业链这4个方面的9项影响因素作为特征,使用极限梯度提升(XGBoost)算法对棉花价格影响因素进行特征评估筛选,选取其中5项特征后,采用引入注意力机制(Attention)的时间卷积网络(TCN) TCN-Attention、TCN、LSTM、GRU等模型对棉花价格进行预测.通过消融实验和对比实验,结果表明:(1)经过XGBoost特征筛选后, TCN-Attention价格预测的平均绝对误差(MAE)和均方根误差(RMSE)为41.47和58.76,与未筛选相比分别降低了77.57%和76.49%.(2)与TCN、LSTM、GRU相比,本文提出的TCN-Attention模型预测结果更准确, MAE和RMSE均降低50%以上,运行时间较LSTM、GRU缩短60%. 展开更多
关键词 价格预测 XGboost TCN atTENTION 消融实验
下载PDF
High-dose-rate intraluminal brachytherapy during preoperative chemoradiation for locally advanced rectal cancers 被引量:3
10
作者 Mutahir Ali Tunio Mansoor Rafi +5 位作者 Altaf Hashmi Rehan Mohsin Abdul Qayyum Mujahid Hasan Amjad Sattar Muhammad Mubarak 《World Journal of Gastroenterology》 SCIE CAS CSCD 2010年第35期4436-4442,共7页
AIM:To determine the feasibility and safety of high dose rate intraluminal brachytherapy(HDR-ILBT) boost during preoperative chemoradiation for rectal cancer.METHODS:Between 2008 and 2009,thirty-six patients with loca... AIM:To determine the feasibility and safety of high dose rate intraluminal brachytherapy(HDR-ILBT) boost during preoperative chemoradiation for rectal cancer.METHODS:Between 2008 and 2009,thirty-six patients with locally advanced rectal cancer(≥ T3 or N+),were treated initially with concurrent capecitabine(825 mg/m2 oral twice daily) and pelvic external beam radiotherapy(EBRT)(45 Gy in 25 fractions),then were randomized to group A;HDR-ILBT group(n = 17) to receive 5.5-7 Gy×2 to gross tumor volume(GTV) and group B;EBRT group(n = 19) to receive 5.4 Gy×3 fractions to GTV with EBRT.All patients underwent total mesorectal excision.RESULTS:Grade 3 acute toxicities were registered in 12 patients(70.6%) in group A and in 8(42.1%) in group B.Complete pathologic response of T stage(ypT0) in group A was registered in 10 patients(58.8%) and in group B,3 patients(15.8%) had ypT0(P < 0.0001).Sphincter preservation was reported in 6/9 patients(66.7%) in group A and in 5/10 patients(50%) in group B(P < 0.01).Overall radiological response was 68.15% and 66.04% in Group A and B,respectively.During a median follow up of 18 mo,late grade 1 and 2 sequelae were registered in 3 patients(17.6%) and 4 patients(21.1%) in the groups A and B,respectively.CONCLUSION:HDR-ILBT was found to be effective dose escalation technique in preoperative chemoradiation for rectal cancers,with higher response rates,downstaging and with manageable acute toxicities. 展开更多
关键词 High dose rate Intraluminal brachytherapy boost Locally advanced rectal cancer Preoperative chemoradiation
下载PDF
High-dose thalidomide increases the risk of peripheral neuropathy in the treatment of ankylosing spondylitis 被引量:2
11
作者 Hong-xia Xue Wen-yi Fu +3 位作者 Hua-dong Cui Li-li Yang Ning Zhang Li-juan Zhao 《Neural Regeneration Research》 SCIE CAS CSCD 2015年第5期814-818,共5页
Thalidomide is an effective drug for the treatment of ankylosing spondylitis but might induce peripheral neuropathy. This major adverse reaction has attracted much concern. The current study aimed to observe the incid... Thalidomide is an effective drug for the treatment of ankylosing spondylitis but might induce peripheral neuropathy. This major adverse reaction has attracted much concern. The current study aimed to observe the incidence of thalidomide-induced peripheral neuropathy among an- kylosing spondylitis patients for 1 year after treatment. In this study, 207 ankylosing spondylitis cases received thalidomide treatment, while 116 ankylosing spondylitis cases received other treat- ments. Results showed that the incidence of thalidomide-induced peripheral neuropathy in the thalidomide group was higher than that in the non-thalidomide group. There was no significant difference in the incidence of neuropathy between the 〈 6 months medication and 〉 6 months medication groups. There were no differences in the mean age, gender, or daily dose between the two groups. The incidence of peripheral neuropathy among patients receiving 25, 50, 75, or 100 mg thalidomide per day was 4.6%, 8.5%, 17.1%, 21.7%, respectively. The incidence was significantly different between the groups receiving 25 mg and 100 mg thalidomide. In conclu- sion, thalidomide can induce peripheral neuropathy within 1 year after treatment of ankylosing spondylitis; however, age and gender have no obvious impact on the incidence of peripheral neuropathy. The incidence of peripheral neuropathy is associated with increasing daily doses of thalidomide. 展开更多
关键词 nerve regeneration peripheral nerve injury THALIDOMIDE ankylosing spondflitis adversereactions peripheral neuropathy prospective study TREatMENT dose treatment time age SEX neuralregeneration
下载PDF
基于遗传算法优化XGBoost模型的地铁乘客出站走行时间预测
12
作者 郭凯旋 肖梅 +1 位作者 刘宇 张皓 《科学技术与工程》 北大核心 2024年第18期7851-7858,共8页
地铁乘客出站走行时间的预测是城市交通运行和管理的重要依据,对其进行准确预测有助于缓解地铁拥堵、优化地铁服务和提高乘客满意度。为了准确预测地铁乘客出站走行时间,首先,基于视频分析软件从监控视频中提取了乘客出站时的走行时间... 地铁乘客出站走行时间的预测是城市交通运行和管理的重要依据,对其进行准确预测有助于缓解地铁拥堵、优化地铁服务和提高乘客满意度。为了准确预测地铁乘客出站走行时间,首先,基于视频分析软件从监控视频中提取了乘客出站时的走行时间和若干特征变量。其次,为了筛选出对走行时间有显著影响的因素,采用相关性分析和最优尺度回归模型进行影响因素分析,并使用遗传算法进行最优特征组合的提取。最终,将提取出的特征作为输入向量,使用极端梯度提升模型(extreme gradient boosting,XGBoost)进行走行时间的预测,并以平均绝对误差等作为评价指标。实验结果表明,本文提出的方法在地铁乘客出站行为预测方面具有较好的效果,平均绝对误差为1.55 s,低于未优化的极端梯度提升模型(1.87 s)、支持向量机(2.03 s)和随机森林(1.96 s)等模型。 展开更多
关键词 遗传算法 极端梯度提升模型 走行时间预测 特征提取
下载PDF
Optimal therapeutic dose and time window of picroside II in cerebral ischemic injury 被引量:1
13
作者 Guangyi Liu Li Zhao +2 位作者 Tingting Wang Meizeng Zhang Haitao Pei 《Neural Regeneration Research》 SCIE CAS CSCD 2014年第15期1437-1445,共9页
A preliminary study from our research group showed that picroside II inhibited neuronal apop- tosis in ischemic penumbra, reduced ischemic volume, and improved neurobehavioral function in rats with cerebral ischemia. ... A preliminary study from our research group showed that picroside II inhibited neuronal apop- tosis in ischemic penumbra, reduced ischemic volume, and improved neurobehavioral function in rats with cerebral ischemia. The aim of the present study was to validate the neuroprotective effects of picroside II and optimize its therapeutic time window and dose in a rat model of cerebral ischemia. We found that picroside Ⅱ inhibited cell apoptosis and reduced the expression of neuron-specific enolase, a marker of neuronal damage, in rats after cerebral ischemic injury. The optimal treatment time after ischemic injury and dose were determined, respectively, as follows: (1) 2.0 hours and 10 mg/kg according to the results of toluidine blue staining; (2) 1.5 hours and 10 mg/kg according to early apoptotic ratio by flow cytometry; (3) 2.0 hours and 10 mg/kg according to immunohistochemical and western blot analysis; and (4) 1.5 hours and 10 mg/kg according to reverse transcription polymerase chain reaction. The present findings suggest that an intraperitoneal injection of 10 mg/kg picroside II 1.5-2.0 hours after cerebral ischemic injury in rats is the optimal dose and time for therapeutic benefit. 展开更多
关键词 nerve regeneration picroside II therapeutic dose time window brain ischemia neuron-specific enolase toluidine blue staining flow cytometry immunohistochemical assay western blot RT-PCR rats NSFC grant neural regeneration
下载PDF
基于变换域分析和XGBoost算法的超短期风电功率预测模型
14
作者 王永生 李海龙 +3 位作者 关世杰 温彩凤 许志伟 高静 《高电压技术》 EI CAS CSCD 北大核心 2024年第9期3860-3870,共11页
为应对传统超短期风电功率预测方法在数据潜在关系挖掘和模型收敛速度等方面存在的问题,提出了一种基于变换域分析和极端梯度提升回归树算法(extreme gradient boosting, XGBoost)的超短期风电功率预测方法。首先,通过时间滑动窗口和风... 为应对传统超短期风电功率预测方法在数据潜在关系挖掘和模型收敛速度等方面存在的问题,提出了一种基于变换域分析和极端梯度提升回归树算法(extreme gradient boosting, XGBoost)的超短期风电功率预测方法。首先,通过时间滑动窗口和风电功率指标进行数据构建和低级特征提取。然后,结合快速傅里叶变换(fastFourier transform, FFT)和哈尔小波变换构成的多层次变换域分析方法对风电数据进行分解,充分考虑频域信息在特征学习中的重要性。最后,建立包含FFT、哈尔小波变换和XGBoost算法组合的超短期风电功率预测模型。实验结果表明,采用的多层次变换域分析方法能够充分挖掘原始特征之间的潜在关系,深入捕捉数据的时序关联性,而且XGBoost算法可以有效提升模型的预测性能,与其他预测模型相比,所提方法在不同数据集上均展现出较高的预测精度和较强的特征提取能力。 展开更多
关键词 风电功率预测 傅里叶变换 小波变换 时间滑动窗口 风电功率指标 梯度提升回归树
下载PDF
SRDAAR-QNPP:a computer code system for the real-time dose assessment of an accident release for Qinshan Nuclear Power Plant 被引量:5
15
作者 Hu Erbang Wang Han(China Institute for Radiation Protection, Taiyuan 030006, China) 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 1994年第3期296-309,共14页
The paper presents a computer code system 'SRDAAR- QNPP' for the real-time dose as-sessment of an accident release for Qinshan Nuclear Power Plant. It includes three parts:thereal-time data acquisition system,... The paper presents a computer code system 'SRDAAR- QNPP' for the real-time dose as-sessment of an accident release for Qinshan Nuclear Power Plant. It includes three parts:thereal-time data acquisition system, assessment computer. and the assessment operating code system. InSRDAAR-QNPP, the wind field of the surface and the lower levels are determined hourly by using amass consistent three-dimension diasnosis model with the topographic following coordinate system.A Lagrangin Puff model under changing meteorological condition is adopted for atmosphericdispersion, the correction for dry and wet depositions. physical decay and partial plume penetrationof the top inversion and the deviation of plume axis caused by complex terrain have been taken in-to account. The calculation domain areas include three square grid areas with the sideline 10 km, 40krn and 160 km and a grid interval 0.5 km, 2.0 km, 8.0 km respectively. Three exposure pathwaysare taken into account:the external exposure from immersion cloud and passing puff, the internalexposure from inhalation and the external exposure from contaminated ground. This system is ableto provide the results of concentration and dose distributions within 10 minutes after the data havebeen inputed. 展开更多
关键词 REAL-time dose assessment computer code system nuclear power plant accident.
下载PDF
Radiation dose detection using a high-power portable optically stimulated luminescence real-time reading system 被引量:2
16
作者 Yi-Hang Wang Hua Chen +2 位作者 Fei Chen Yong-Gang Yuan Tai-Ping Peng 《Nuclear Science and Techniques》 SCIE CAS CSCD 2018年第10期245-253,共9页
Optically stimulated luminescence(OSL) reading systems are becoming smaller and capable of real-time detection. To improve real-time and multipurpose radiation dosimetry readings, we built a real-time continuous-wave(... Optically stimulated luminescence(OSL) reading systems are becoming smaller and capable of real-time detection. To improve real-time and multipurpose radiation dosimetry readings, we built a real-time continuous-wave(RCW) OSL reading system. This system is both small and lightweight, and it employs powerful laser excitation(478 mW/cm^2) at the dosimetry probe location. We investigate the possibility of using the RCW mode to read the radiation luminescence(RL) or OSL by using a singlecrystal Al_2O_3:C dosimeter in a low-dose-rate137 Cs y field.Our results indicate that the RL/OSL follows a stable and uniform distribution. The minimum detected doses associated with the RL, OSL, and RL + OSL signals are2.1 9 10^(-2), 3.17 9 10^(-1), and 5.7 9 10^(-2) l Gy, respectively. This device provides a framework for the future development of applications for practical radiation dose measurements. 展开更多
关键词 OSL REAL-time READING Al2O3:C Radiation dose
下载PDF
Intentionally unilateral prostatic artery embolization:Patient selection,technique and potential benefits
17
作者 Hippocrates Moschouris Konstantinos Stamatiou 《World Journal of Radiology》 2024年第9期380-388,共9页
BACKGROUND Prostatic artery embolization(PAE)is a promising but also technically demanding interventional radiologic treatment for symptomatic benign prostatic hyperplasia.Many technical challenges in PAE are associat... BACKGROUND Prostatic artery embolization(PAE)is a promising but also technically demanding interventional radiologic treatment for symptomatic benign prostatic hyperplasia.Many technical challenges in PAE are associated with the complex anatomy of prostatic arteries(PAs)and with the systematic attempts to catheterize the PAs of both pelvic sides.Long procedure times and high radiation doses are often the result of these attempts and are considered significant disadvantages of PAE.The authors hypothesized that,in selected patients,these disadvantages could be mitigated by intentionally embolizing PAs of only one pelvic side.AIM To describe the authors’approach for intentionally unilateral PAE(IU-PAE)and its potential benefits.METHODS This was a single-center retrospective study of patients treated with IU-PAE during a period of 2 years.IU-PAE was applied in patients with opacification of more than half of the contralateral prostatic lobe after angiography of the ipsilateral PA(subgroup A),or with markedly asymmetric prostatic enlargement,with the dominant prostatic lobe occupying at least two thirds of the entire gland(subgroup B).All patients treated with IU-PAE also fulfilled at least one of the following criteria:Severe tortuosity or severe atheromatosis of the pelvic arteries,non-visualization,or visualization of a tiny(<1 mm)contralateral PA on preprocedural computed tomographic angiography.Intraprocedural contrast-enhanced ultrasonography(iCEUS)was applied to monitor prostatic infarction.IU-PAE patients were compared to a control group treated with bilateral PAE.RESULTS IU-PAE was performed in a total 13 patients(subgroup A,n=7;subgroup B,n=6).Dose-area product,fluoroscopy time and operation time in the IU-PAE group(9767.8μGy∙m^(2),30.3 minutes,64.0 minutes,respectively)were significantly shorter(45.4%,35.9%,45.8%respectively,P<0.01)compared to the control group.Clinical and imaging outcomes did not differ significantly between the IU-PAE group and the control group.In the 2 clinical failures of IU-PAE(both in subgroup A),the extent of prostatic infarction(demonstrated by iCEUS)was significantly smaller compared to the rest of the IU-PAE group.CONCLUSION In selected patients,IU-PAE is associated with comparable outcomes,but with lower radiation exposure and a shorter procedure compared to bilateral PAE.iCEUS could facilitate patient selection for IU-PAE. 展开更多
关键词 Prostatic artery embolization UNILatERAL Computed tomographic angiography dose area product Fluoroscopy time Prostatic infarction
下载PDF
Predictive formulas expressing relationship between dose rate and survival time in total body irradiation in mice
18
作者 Sung Jang Chung 《Journal of Biomedical Science and Engineering》 2011年第11期707-718,共12页
The Gompertz model is the long-time well-known mathematical model of exponential expression among mortality models in the literature that are used to describe mortality and survival data of a population. The death rat... The Gompertz model is the long-time well-known mathematical model of exponential expression among mortality models in the literature that are used to describe mortality and survival data of a population. The death rate of the “probacent” model developed by the author based on animal experiments, clinical applications and mathematical reasoning was applied to predict age-specific death rates in the US elderly population, 2001, and to express a relationship among dose rate, duration of exposure and mortality probability in total body irradiation in humans. The results of both studies revealed a remarkable agreement between “probacent”-formula-predicted and published-reported values of death rates in the US elderly population or mortality probabilities in total body irradiation in humans (p - value > 0.995 in χ2 test in each study). In this study, both the Gompertz and “probacent” models are applied to the Sacher’s comprehensive experimental data on survival times of mice daily exposed to various doses of total body irradiation until death occurs with an assumption that each of both models is applicable to the data. The purpose of this study is to construct general formulas expressing relationship between dose rate and survival time in total body irradiation in mice. In addition, it is attempted to test which model better fits the reported data. The results of the comparative study revealed that the “probacent” model not only fit the Sacher’s reported data but also remarkably better fit the reported data than the Gompertz model. The “probacent” model might be hopefully helpful in research in human tolerance to low dose rates for long durations of exposure in total body irradiation, and further in research in a variety of biomedical phenomena. 展开更多
关键词 LETHAL Radiation dose Total Body Irradiation Formula of SURVIVAL time in MICE dose-Survival Curve “Probacent” MODEL GOMPERTZ MODEL
下载PDF
基于UKDE和XGBoost的航班过站时间动态预测
19
作者 吴薇薇 熊奥萍 唐红武 《南京航空航天大学学报》 CAS CSCD 北大核心 2023年第6期1016-1024,共9页
为了提高机场运行高峰时航班过站时间预测的精度及可靠性,研究了一种结合无偏核密度估计(Unbiased kernel density estimation,UKDE)和极端梯度提升决策树(Extreme gradient boosting,XGBoost)模型的航班过站时间动态预测方法。首先,考... 为了提高机场运行高峰时航班过站时间预测的精度及可靠性,研究了一种结合无偏核密度估计(Unbiased kernel density estimation,UKDE)和极端梯度提升决策树(Extreme gradient boosting,XGBoost)模型的航班过站时间动态预测方法。首先,考虑模型输入变量航班密度的连续性和不确定性变化,利用UKDE法估计机场航班密度,将其作为动态指标输入模型。其次,引入量子粒子群(Quantum particle swarm optimization,QPSO)法优化XGBoost模型。最后,考虑前序航班延误发生前后输入特征的变化,利用初始预测结果对航班密度进行修正,得到二阶段预测结果。研究结果表明:本文方法在高峰时段的预测平均绝对误差为7.365 min,效果优于随机森林(Random forest,RF)、粒子群(Particle swarm optimization,PSO)-XGBoost和XGBoost,修正后的预测结果平均绝对误差减少了3.373 min;模型输入参数按敏感性程度由高到低依次为航班密度、前序航班提前到港时间和延误到港时间。 展开更多
关键词 航空运输 时间预测 极端梯度提升决策树 航班过站保障 核密度估计
下载PDF
Optimal timing for the oral administration of DaCheng-Qi decoction based on the pharmacokinetic and pharmacodynamic targeting of the pancreas in rats with acute pancreatitis 被引量:5
20
作者 Yu-Mei Zhang Lin Zhu +7 位作者 Xian-Lin Zhao Huan Chen Hong-Xin Kang Jian-Lei Zhao Mei-Hua Wan Juan Li Lv Zhu Wen-Fu Tang 《World Journal of Gastroenterology》 SCIE CAS 2017年第39期7098-7109,共12页
AIM To identify the optimal oral dosing time of Da-Cheng-Qi decoction(DCQD) in rats with acute pancreatitis(AP) based on the pharmacokinetic and pharmacodynamic parameters.METHODS First, 24 male Sprague-Dawley rats we... AIM To identify the optimal oral dosing time of Da-Cheng-Qi decoction(DCQD) in rats with acute pancreatitis(AP) based on the pharmacokinetic and pharmacodynamic parameters.METHODS First, 24 male Sprague-Dawley rats were divided into a sham-operated group [NG(a)] and three model groups [4 h G(a), 12 h G(a) and 24 h G(a)]. The NG(a) and model groups were administered DCQD(10 g/kg.BW) intragastrically at 4 h, 4 h, 12 h and 24 h, respectively, after AP models induced by 3% sodium taurocholate. Plasma samples were collected from the tails at 10 min, 20 min, 40 min, 1 h, 2 h, 4 h, 8 h, 12 h and 24 h after a single dosing with DCQD. Plasma and pancreatic tissue concentrations of the major components of DCQD were determined by high-performance liquid chromatography tandem mass spectroscopy. The pharmacokinetic parameters and serum amylase were detected and compared. Second, rats were divided into a sham-operated group [NG(b)] and three treatment groups [4 h G(b), 12 h G(b) and 24 h G(b)] with three corresponding control groups [MG(b)s]. Blood and pancreatic tissues were collected 24 h after a single dosing with DCQD. Serum amylase, inflammatory cytokines and pathological scores of pancreatic tissues were detected and compared.RESULTS The concentrations of emodin, naringin, honokiol, naringenin, aloe-emodin, chrysophanol and rheochrysidin in the 12 h G(a) group were higher than those in the 4 h G(a) group in the pancreatic tissues(P < 0.05). The area under the plasma concentration-time curve from time 0 to the time of the last measurable concentration values(AUC0→t) for rhein, chrysophanol, magnolol and naringin in the 12 h G(a) group were larger than those in the 4 h G(a) or 24 h G(a) groups. The 12 h G(a) group had a higher Cmax than the other two model groups. The IL-10 levels in the 12 h G(b) and 24 h G(b) groups were higher than in the MG(b)s(96.55 ± 7.84 vs 77.46 ± 7.42, 251.22 ± 16.15 vs 99.72 ± 4.7 respectively, P < 0.05), while in the 24 h G(b) group, the IL-10 level was higher than in the other two treatment groups(251.22 ± 16.15 vs 154.41 ± 12.09/96.55 ± 7.84, P < 0.05). The IL-6 levels displayed a decrease in the 4 h G(b) and 12 h G(b) groups compared to theMG(b)s(89.99 ± 4.61 vs 147.91 ± 4.36, 90.82 ± 5.34 vs 171.44 ± 13.43, P < 0.05). CONCLUSION Late-time dosing may have higher concentrations of the most major components of DCQD, with better pharmacokinetics and pharmacodynamics of antiinflammation than early-time dosing, which showed the late time to be the optimal dosing time of DCQD for AP. 展开更多
关键词 Da-Cheng-Qi decoction Acute pancreatitis Pharmacokinetics Oral dosing time PHARMACODYNAMICS
下载PDF
上一页 1 2 41 下一页 到第
使用帮助 返回顶部