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Development of a new correlation to calculate permeability for flows with high Knudsen number

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Chinese Physics B 2016年第2期25卷 271-277页

作者： Esmaeil dehdashti Department of Mechanical Engineering University of Tehran

Flows with high Knudsen number play a prominent role in many engineering applications. The present study is an effort toward the simulation of flow with high Knudsen number using modified lattice Boltzmann method （LBM） through a porous medium in a channel. The effect of collision between molecules and solid walls, which is required to accurately simulate transition flow regime, is taken into account using a modified relaxation time. Slip velocity on the wall, which is another significant difficulty in simulating transition flow regime, is captured using the slip reflection boundary condition （SrBC）. The geometry of porous medium is considered as in-line and staggered. The results are in good a.r.ement with previous works. A new correlation is obtained between permeability, Knudsen number and porosity for flows in transition flow regimes.

关键词： flow in porous micro-channel lattice Boltzmann method high Knudsen number permeability

Simulation of fluid-structure interaction in a microchannel using the lattice Boltzmann method and size-dependent beam element on a graphics processing unit

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Chinese Physics B 2014年第8期23卷 389-395页

作者： Vahid Esfahanian Esmaeil dehdashti Amir Mehdi Dehrouye-Semnani Department of Mechanical Engineering University of Tehran

Fluid-structure interaction （FSI） problems in microchannels play a prominent role in many engineering applications. The present study is an effort toward the simulation of flow in microchannel considering FSI. The bottom boundary of the microchannel is simulated by size-dependent beam elements for the finite element method （FEM） based on a modified cou- ple stress theory. The lattice Boltzmann method （LBM） using the D2Q13 LB model is coupled to the FEM in order to solve the fluid part of the FSI problem. Because of the fact that the LBM generally needs only nearest neighbor information, the algorithm is an ideal candidate for parallel computing. The simulations are ca.r.ed out on graphics processing units （GPUs） using computed unified device architecture （CUDA）. In the present study, the governing equations are non-dimensionalized and the set of dimensionless groups is exhibited to show their effects on micro-beam displacement. The numerical results show that the displacements of the micro-beam predicted by the size-dependent beam element are smaller than those by the classical beam element.

关键词： fluid-structure interaction graphics processing unit lattice Boltzmann method size-dependentbeam element

Fluid-Structure Interaction in Microchannel Using Lattice Boltzmann Method and Size-Dependent Beam Element

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Advances in Applied Mathematics and Mechanics 2014年第3期6卷 345-358页

作者： V.Esfahanian E.dehdashti A.M.Dehrouyeh-Semnani School of Mechanical Engineering University of TehranTehran 14395-515Iran

Fluid-structure interaction(FSI)problems in microchannels play prominent roles in many engineering *** present study is an effort towards the simulation of flow in microchannel considering *** boundary of the microchannel is assumed to be rigid and the bottom boundary,which is modeled as a Bernoulli-Euler beam,is simulated by size-dependent beam elements for finite element method(FEM)based on a modified couple stress *** lattice Boltzmann method(LBM)using D2Q13 LB model is coupled to the FEM in order to solve fluid part of FSI *** the present study,the governing equations are non-dimensionalized and the set of dimensionless groups is exhibited to show their effects on micro-beam *** numerical results show that the displacements of the micro-beam predicted by the size-dependent beam element are smaller than those by the classical beam element.

关键词： Fluid-structure interaction microchannel lattice Boltzmann method size-dependent beam element

MrI,^18F—FDG PET／CT及PET／Mr成像评估妇科肿瘤

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中华核医学与分子影像杂志 2018年第4期38卷 295-301页

作者：王玉彭新桂滕皋军 Susanna I. Lee Catalano OA dehdashti F 东南大学附属中大医院放射科南京210009 Department of radiology Massachusetts General Hospital Harvard Medical School Boston Massachusetts Department of radiology University of Naples Parthenope and SDN Istituto Ricerca Diagnostica Nucleare Naples Italy Department of Nuclear Medicine Mallinckrodt Institute of Radiology Washington University St. Louis Missouri

MrI和^18F-脱氧葡萄糖（FDG）PET／CT在妇科癌症患者的诊疗中扮演着核心和互补角色。由于治疗通常需要联合手术、放疗以及化疗，因此成像对病情分期和评估预后非常重要。该文综述了运用上述2种成像模式在早期评估3种常见妇科肿瘤（宫颈... 详细信息

MrI和^18F-脱氧葡萄糖（FDG）PET／CT在妇科癌症患者的诊疗中扮演着核心和互补角色。由于治疗通常需要联合手术、放疗以及化疗，因此成像对病情分期和评估预后非常重要。该文综述了运用上述2种成像模式在早期评估3种常见妇科肿瘤（宫颈癌、子宫内膜癌和卵巢上皮肿瘤）中的应用。重点提出了影响治疗的影像特征，以及2种成像方式的相对优势和不足。影像评估先期治疗后肿瘤复发以及后续姑息治疗方法的选择。并对MrI和PET中较新的功能和分子技术进行效果评估。最后，该文还介绍PET／Mr成像的初期经验，PET／Mr是一种新型技术，很有潜力成为个体化妇科肿瘤治疗方案制订的重要方法。

关键词： Cu-双乙酰基(N4-硫代甲基半缩二氨基脲)PET 16α-^18F-氟代-17β-雌二醇PET 弥散加权成像动态对比增强MrI 灌注MrI

18F-氟脱氧葡萄糖的摄取作为原发性宫颈癌放疗后的预后指标

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世界核心医学期刊文摘（妇产科学分册） 2006年第9期2卷 56-56页

作者： dehdashti F. P.W. Grigsby 李奎 Department of radiation Oncology Mallinckrodt Institute of Radiology Washington University School of Medicine 4921 Parkview Place St. Louis MO 63110 United States

Purpose. We evaluated the prognostic significance of tumor metabolic activity on pretreatment positron emission tomography using the glucose analog F- 18 fluorodeoxyglucose (FDG- PET) in patients with carcinoma of the cervix undergoing radiotherapy with or without concurrent chemotherapy. Methods. We studied 96 consecutive patients who underwent FDG- PET prior to initiation of radiotherapy with or without concurrent chemotherapy for carcinoma of the cervix. Pretreatment FDG uptake of the primary tumor was assessed with the semiquantitative standardized uptake value (SUV) and correlated with di-sease- free and overall survival. Survival was estimated by the Kaplan- Meier method. Univariate and multivariate analyses were performed with the logistic likelihood ratio test and the Cox proportional hazards model, respectively. results. Five-year disease- free survivals in patients with maximal SUV re 71% and 52% (P = 0.0289)- respectively, while overall survivals were 72% and 69% (P = 0.4), respectively. On multivariate analysis, lymph node metastasis on FDG- PET was found to be predictive of disease- free survival (P r FDG and FIGO Stage I disease were found to be marginally predictive of disease- free survival (P = 0.055 and P = 0.058, respectively). Conclusions. FDG uptake within primary cervical cancer, as measured by SUV, is predictive of disease- free survival in patients undergoing radiotherapy for cervical cancer. High FDG uptake may be useful in identifying patients who may require more aggressive initial therapy.

关键词：氟脱氧葡萄糖标准摄取值预后指标宫颈癌放疗后原发性正电子发射计算机断层扫描 Cox比例风险模型

对比吲哚菁绿荧光血管造影与数字减影血管造影在脑动静脉畸形手术中的应用(英文)

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中华神经外科疾病研究杂志 2014年第6期13卷 535-535页

作者： Bilbao CJ Bhalla T Dalal S Patel H dehdashti Ar

BACKGrOUND The potential utility of intraoperative microscope-integrated indocyanine green( ICG) fluorescence angiography in the surgery of brain arteriovenous malformations( AVMs) and evaluation of the completeness of resection is *** catheter angiography is considered the gold standard. We evaluated the value of ICG and intraoperative catheter angiography in this setting. METHODS Between January 2009 and July 2013,37 patients with brain AVMs underwent surgical resection of their vascularlesions. ICG videoangiography and an intraoperative catheter angiography were performed in 32 cases,and a.r.utine postoperative angiogram was performed within 48 h to 2 weeks after surgery. The usefulness of ICG findings and the ability to confirm total resection and to identify residual nidus or persistent shunt were assessed and compared to intraoperative and postoperative digital subtraction angiography,respectively. rESULTS There were 7 grade 1,11 grade 2,11 grade 3 and 3 grade 4 Spetzler-Martin classification AVMs. ICG angiography helped to distinguish AVM vessels in 26 patients. In 31 patients,it demonstrated that there was no residual shunting. In one patient,a.r.sidual AVM was identified and further resected. Intraoperative catheter angiography detected two additional small residuals that were missed by ICG angiography,both deep in the surgical cavity. Further resection of the AVM was performed,and total resection was confirmed by a.r.peat intraoperative angiogram. Postoperative angiography in a patient with a grade 4 lesion revealed one additional small deep residual AVM nidus with persistent late shunting missed on both ICG and intraoperative angiography. Overall ICG angiography missed three out of four residual AVMs after initial resection, while the intraoperative angiogram missed *** Although ICG angiography is a helpful adjunct in the surgery of some brain AVMs,it's yield in detecting residual AVM nidus or shunt is low,especially for dee

关键词：神经外科疾病临床研究患者

PET/CT评估高风险子宫内膜癌腹膜后淋巴结转移的诊断效能:a.r.N 6671/GOG 0233试验结果

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国际医学放射学杂志 2017年第4期 463-463页

作者： M.a.r. Z.Zhang F.dehdashti S.I.Lee H.Marques S.Ali 王争 Department of Medical Imaging NCSB 1C569 Toronto General Hospital University of Toronto University Health Network

摘要目的评估以18F-氟脱氧葡萄糖（FDG）为示踪剂的正电子发射体层成像（PET）联合增强CT检测高危子宫内膜癌淋巴结（LN）转移的诊断准确性。材料与方法该项前瞻性多中心研究获得机构伦理委员会批准并符合HIPAA,所有病人均签署书面知情...

摘要目的评估以18F-氟脱氧葡萄糖（FDG）为示踪剂的正电子发射体层成像（PET）联合增强CT检测高危子宫内膜癌淋巴结（LN）转移的诊断准确性。材料与方法该项前瞻性多中心研究获得机构伦理委员会批准并符合HIPAA,所有病人均签署书面知情同意书。数据来自2010年1月—2013年6月间215例病人。所有病人均接受PET/CT和腹盆腔淋巴

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