Quantitative analysis of digital images requires detection and segmentation of the borders of the object of interest. Accurate segmentation is required for volume determination, 3D rendering, radiation therapy, and su...Quantitative analysis of digital images requires detection and segmentation of the borders of the object of interest. Accurate segmentation is required for volume determination, 3D rendering, radiation therapy, and surgery planning. In medical images, segmentation has traditionally been done by human experts. Substantial computational and storage requirements become especially acute when object orientation and scale have to be considered. Therefore, automated or semi-automated segmentation techniques are essential if these software applications are ever to gain widespread clinical use. Many methods have been proposed to detect and segment 2D shapes, most of which involve template matching. Advanced segmentation techniques called Snakes or active contours have been used, considering deformable models or templates. The main purpose of this work is to apply segmentation techniques for the definition of 3D organs (anatomical structures) when big data information has been stored and must be organized by the doctors for medical diagnosis. The processes would be implemented in the CT images from patients with COVID-19.展开更多
目的:大量研究表明,非侵入性神经调控技术能够有效改善脑卒中后非流畅性失语的症状,然而,针对该类技术的最优刺激方案仍有待深入验证与探究。此次研究借助网状Meta分析方法,系统评价不同非侵入性神经调控技术改善脑卒中后非流畅性失语...目的:大量研究表明,非侵入性神经调控技术能够有效改善脑卒中后非流畅性失语的症状,然而,针对该类技术的最优刺激方案仍有待深入验证与探究。此次研究借助网状Meta分析方法,系统评价不同非侵入性神经调控技术改善脑卒中后非流畅性失语患者言语功能的效应。方法:检索CNKI、万方、维普、CBM、PubMed、Cochrane图书馆、Embase和Web of Science数据库,筛选有关非侵入性神经调控技术治疗脑卒中后非流畅性失语的随机对照试验,检索时限截至2025-06-01。对照组采用常规治疗或假刺激,试验组在对照组治疗的基础上加入非侵入性神经调控技术,结局指标为西方失语成套测验、汉语失语成套测验、日常生活交流能力评定量表。采用Stata 17.0软件对结局指标进行传统Meta分析和网状Meta分析,采用GRADE对结局指标进行证据等级评价。结果:共纳入33篇随机对照试验,涉及10种非侵入性神经调控方式。①传统Meta分析结果显示,低频重复经颅磁刺激右侧Broca区、经颅直流电刺激双侧Broca区、经颅直流电刺激左侧Broca区可改善患者西方失语成套测验评分(P<0.001),低频重复经颅磁刺激右侧Broca区、低频重复经颅磁刺激颞上回后部、低频重复经颅磁刺激右侧Broca区联合高频重复经颅磁刺激左侧Broca区可改善患者汉语失语成套测验评分(P<0.05),低频重复经颅磁刺激右侧Broca区、经颅直流电刺激双侧Broca区、连续性θ爆发刺激右侧Broca区联合间歇性θ爆发刺激左侧Broca区、高频重复经颅磁刺激刺激右侧Broca区、低频重复经颅磁刺激右侧Broca区联合高频刺激左侧Broca区可改善患者日常生活交流能力评定量表评分(P<0.05)。②网状Meta分析结果显示,低频重复经颅磁刺激右侧Broca区改善患者西方失语成套测验评分和汉语失语成套测验评分的疗效更佳[SMD=1.13,95%CI(0.59,1.67),P<0.05;SMD=4.73,95%CI(1.28,8.18),P<0.05],经颅直流电刺激双侧Broca区在改善患者日常生活交流能力评定量表评分的疗效更佳[SMD=1.81,95%CI(0.51,2.12),P<0.05]。③GRADE证据等级评价结果显示,西方失语成套测验、汉语失语成套测验、日常生活交流能力评定量表结局指标的证据等级均为低级。结论:不同非侵入性神经调控方式均能改善脑卒中后非流畅性失语患者的言语功能,低频重复经颅磁刺激右侧Broca区在改善多维度言语功能方面,尤其在自发言语连贯性、听觉理解准确性及命名流畅性等方面疗效显著;经颅直流电刺激双侧Broca区更侧重改善患者的日常生活交流能力,但研究结果受纳入研究的数量及质量影响,证据等级较低,仍需更多高质量的研究进一步验证。展开更多
Functionally graded materials, including their characterization, properties and production methods are a new rapidly developing field of materials science. The aims of this review are to systematize the basic producti...Functionally graded materials, including their characterization, properties and production methods are a new rapidly developing field of materials science. The aims of this review are to systematize the basic production techniques for manufacturing functionally graded materials. Attention is paid to the principles for obtaining graded structure mainly in the metal based functionally graded materials. Several unpublished results obtained by the authors have been discussed briefly. Experimental methods and theoretical analysis for qualitative and quantitative estimation of graded properties have also been presented. The article can be useful for people who work in the field of functionally graded structures and materials, and who need a compact informative review of recent experimental and theoretical activity in this area.展开更多
In this study the medium-term response of beach profiles was investigated at two sites： a gently sloping sandy beach and a steeper mixed sand and gravel beach. The former is the Duck site in North Carolina, on the ea...In this study the medium-term response of beach profiles was investigated at two sites： a gently sloping sandy beach and a steeper mixed sand and gravel beach. The former is the Duck site in North Carolina, on the east coast of the USA, which is exposed to Atlantic Ocean swells and storm waves, and the latter is the Milford-on-Sea site at Christchurch Bay, on the south coast of England, which is partially sheltered from Atlantic swells but has a directionally bimodal wave exposure. The data sets comprise detailed bathymetric surveys of beach profiles covering a period of more than 25 years for the Duck site and over 18 years for the Milford-on-Sea site. The structure of the data sets and the data-driven methods are described. Canonical correlation analysis （CCA） was used to find linkages between the wave characteristics and beach profiles. The sensitivity of the linkages was investigated by deploying a wave height threshold to filter out the smaller waves incrementally. The results of the analysis indicate that, for the gently sloping sandy beach, waves of all heights are important to the morphological response. For the mixed sand and gravel beach, filtering the smaller waves improves the statistical fit and it suggests that low-height waves do not play a primary role in the medium-term morohological resoonse, which is primarily driven by the intermittent larger storm waves.展开更多
文摘Quantitative analysis of digital images requires detection and segmentation of the borders of the object of interest. Accurate segmentation is required for volume determination, 3D rendering, radiation therapy, and surgery planning. In medical images, segmentation has traditionally been done by human experts. Substantial computational and storage requirements become especially acute when object orientation and scale have to be considered. Therefore, automated or semi-automated segmentation techniques are essential if these software applications are ever to gain widespread clinical use. Many methods have been proposed to detect and segment 2D shapes, most of which involve template matching. Advanced segmentation techniques called Snakes or active contours have been used, considering deformable models or templates. The main purpose of this work is to apply segmentation techniques for the definition of 3D organs (anatomical structures) when big data information has been stored and must be organized by the doctors for medical diagnosis. The processes would be implemented in the CT images from patients with COVID-19.
文摘目的:大量研究表明,非侵入性神经调控技术能够有效改善脑卒中后非流畅性失语的症状,然而,针对该类技术的最优刺激方案仍有待深入验证与探究。此次研究借助网状Meta分析方法,系统评价不同非侵入性神经调控技术改善脑卒中后非流畅性失语患者言语功能的效应。方法:检索CNKI、万方、维普、CBM、PubMed、Cochrane图书馆、Embase和Web of Science数据库,筛选有关非侵入性神经调控技术治疗脑卒中后非流畅性失语的随机对照试验,检索时限截至2025-06-01。对照组采用常规治疗或假刺激,试验组在对照组治疗的基础上加入非侵入性神经调控技术,结局指标为西方失语成套测验、汉语失语成套测验、日常生活交流能力评定量表。采用Stata 17.0软件对结局指标进行传统Meta分析和网状Meta分析,采用GRADE对结局指标进行证据等级评价。结果:共纳入33篇随机对照试验,涉及10种非侵入性神经调控方式。①传统Meta分析结果显示,低频重复经颅磁刺激右侧Broca区、经颅直流电刺激双侧Broca区、经颅直流电刺激左侧Broca区可改善患者西方失语成套测验评分(P<0.001),低频重复经颅磁刺激右侧Broca区、低频重复经颅磁刺激颞上回后部、低频重复经颅磁刺激右侧Broca区联合高频重复经颅磁刺激左侧Broca区可改善患者汉语失语成套测验评分(P<0.05),低频重复经颅磁刺激右侧Broca区、经颅直流电刺激双侧Broca区、连续性θ爆发刺激右侧Broca区联合间歇性θ爆发刺激左侧Broca区、高频重复经颅磁刺激刺激右侧Broca区、低频重复经颅磁刺激右侧Broca区联合高频刺激左侧Broca区可改善患者日常生活交流能力评定量表评分(P<0.05)。②网状Meta分析结果显示,低频重复经颅磁刺激右侧Broca区改善患者西方失语成套测验评分和汉语失语成套测验评分的疗效更佳[SMD=1.13,95%CI(0.59,1.67),P<0.05;SMD=4.73,95%CI(1.28,8.18),P<0.05],经颅直流电刺激双侧Broca区在改善患者日常生活交流能力评定量表评分的疗效更佳[SMD=1.81,95%CI(0.51,2.12),P<0.05]。③GRADE证据等级评价结果显示,西方失语成套测验、汉语失语成套测验、日常生活交流能力评定量表结局指标的证据等级均为低级。结论:不同非侵入性神经调控方式均能改善脑卒中后非流畅性失语患者的言语功能,低频重复经颅磁刺激右侧Broca区在改善多维度言语功能方面,尤其在自发言语连贯性、听觉理解准确性及命名流畅性等方面疗效显著;经颅直流电刺激双侧Broca区更侧重改善患者的日常生活交流能力,但研究结果受纳入研究的数量及质量影响,证据等级较低,仍需更多高质量的研究进一步验证。
文摘Functionally graded materials, including their characterization, properties and production methods are a new rapidly developing field of materials science. The aims of this review are to systematize the basic production techniques for manufacturing functionally graded materials. Attention is paid to the principles for obtaining graded structure mainly in the metal based functionally graded materials. Several unpublished results obtained by the authors have been discussed briefly. Experimental methods and theoretical analysis for qualitative and quantitative estimation of graded properties have also been presented. The article can be useful for people who work in the field of functionally graded structures and materials, and who need a compact informative review of recent experimental and theoretical activity in this area.
基金supported by the UK Natural Environment Research Council(Grant No.NE/J005606/1)the UK Engineering and Physical Sciences Research Council(Grant No.EP/C005392/1)the Ensemble Estimation of Flood Risk in a Changing Climate(EFRa CC)project funded by the British Council under its Global Innovation Initiative
文摘In this study the medium-term response of beach profiles was investigated at two sites： a gently sloping sandy beach and a steeper mixed sand and gravel beach. The former is the Duck site in North Carolina, on the east coast of the USA, which is exposed to Atlantic Ocean swells and storm waves, and the latter is the Milford-on-Sea site at Christchurch Bay, on the south coast of England, which is partially sheltered from Atlantic swells but has a directionally bimodal wave exposure. The data sets comprise detailed bathymetric surveys of beach profiles covering a period of more than 25 years for the Duck site and over 18 years for the Milford-on-Sea site. The structure of the data sets and the data-driven methods are described. Canonical correlation analysis （CCA） was used to find linkages between the wave characteristics and beach profiles. The sensitivity of the linkages was investigated by deploying a wave height threshold to filter out the smaller waves incrementally. The results of the analysis indicate that, for the gently sloping sandy beach, waves of all heights are important to the morphological response. For the mixed sand and gravel beach, filtering the smaller waves improves the statistical fit and it suggests that low-height waves do not play a primary role in the medium-term morohological resoonse, which is primarily driven by the intermittent larger storm waves.
