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1.
利用切片的二维空间相关操作实现血管的三维重建   总被引:2,自引:0,他引:2  
相关(Correlation)作为两个图形相似程度的度量,被广泛的用于图形图像自动识别中.为对血管的二维切片图像进行分析并重构出血管以及血管中轴线的三维空间形貌,我们利用快速傅立叶变换(FFT)及反变换对切片进行空间相关操作,几乎一步即可确定出中轴线与切片的交点,从而给出中轴线的空间坐标.我们求出了血管的半径,利用这些结果,绘出了血管中轴线的三维曲线及其投影线,并且利用计算机软件画出了血管的三维造型,在该造型中作血管切片,结果与初始的切片数据一致.文中分析了相关法进行图像处理的优点与局限性,对利用近代光学信息处理的手段进行切片三维重建的思路进行了讨论.  相似文献   

2.
血管的三维重建   总被引:2,自引:0,他引:2  
对血管的三维重建问题,我们假定血管为等径管道,通过分析其几何特性,给出了确定其管道中轴线和半径的数学模型--搜索每个切片截面,求最大内切圆,该内切圆圆心即为切片截面与管道中轴线的交点,该内切圆半径即为管道半径,再通过拟合各个交点求出轴心线. 本模型中,我们确立了两种有效的误差分析方法;并由此发现由于中轴线与切片交角过小会使结果产生较大偏差.为解决此问题,我们从其它方向重新对血管进行切割,再进行处理求解,得到更加精确的结果.  相似文献   

3.
介绍了细胞凋亡不仅在存在于动物细胞中,也发生于植物个体发育中,并起着重要作用。植物细胞凋亡与动物细胞凋亡有相似的形态学和生化特征;植物细胞凋亡中存在着核酸科的激活;也可能有Caspase蛋白酶的参与。对一些与植物细胞凋亡有关的基因等问题进行了综述。  相似文献   

4.
梁玮  姚岚  刘宝林 《制冷学报》2017,(1):113-118
样本质量是体现生物样本库价值的关键,但是低温保存可能导致细胞凋亡及基因表达量的变化,影响样本质量。本文采用流式细胞术与实时荧光定量PCR(qPCR)的方法,研究了Hep-G2细胞在不同条件下冻存后凋亡及相关基因表达量。结果表明:低温保存影响Hep-G2细胞的成活率、凋亡情况及某些凋亡基因表达量。无论冻存过程中是否添加低温保护剂,低温保存都会对细胞的凋亡相关基因表达带来不同程度的影响。不添加保护剂冻存会导致细胞死亡,添加10%DMSO冻存会导致细胞凋亡,复苏培养24 h后细胞的成活率、凋亡情况与相关基因表达量基本与对照组水平一致。  相似文献   

5.
讨论了金属微观结构研究中三维重构的意义和必要性,详细介绍了基于连续切片的三维重构方法的两个主要部分:图像获取和数据处理.指出了图像获取中的主要问题与解决办法,讨论了图像数据处理中的各种方法和软件工具.最后介绍了基于连续切片的三维重构技术的最新进展,并总结了基于连续切片的三维重构方法推广应用的关键.  相似文献   

6.
嵌合抗CD20 Fab′诱导Raji细胞凋亡   总被引:1,自引:0,他引:1  
为了研究嵌合抗CD2 0基因工程抗体Fab′的抗肿瘤活性及其抗肿瘤机制 ,利用3H掺入法测定嵌合抗CD2 0Fab′对Raji细胞生长的影响 ,结果显示嵌合抗CD2 0Fab′对Raji细胞的生长具有抑制作用 ,利用流式细胞仪测定嵌合抗CD2 0Fab′诱导Raji细胞凋亡作用 ,结果显示嵌合抗CD2 0Fab′可诱导Raji细胞凋亡作用。这些实验结果证明嵌合抗CD2 0Fab′通过诱导Raji细胞凋亡的机制抑制Raji细胞生长。  相似文献   

7.
研究不同浓度Mg-6Zn合金浸提液对大鼠肠上皮细胞IEC-6的凋亡及凋亡相关基因Caspase-3表达的影响。将Mg-6Zn合金制成不同浓度(20%和40%)的浸提液体外培养大鼠肠上皮细胞IEC-6,并以含10%胎牛血清的高糖DMEM(Dulbecco′s modified Eagle′s medium)培养基作为阴性对照。采用噻唑蓝(MTT)法通过计算细胞相对增殖率检测不同浓度合金浸提液对IEC-6细胞的毒性作用;采用流式细胞仪检测不同浓度合金浸提液对IEC-6细胞凋亡的影响;采用逆转录聚合酶链反应(RT-PCR)法检测不同浓度合金浸提液对IEC-6细胞凋亡相关基因Caspase-3mRNA表达的影响。实验结果表明,20%和40%两种浓度的镁合金浸提液在体外培养IEC-6细胞第七天时细胞毒性分级分别为0级和1级,属于无毒性,符合医用材料细胞毒性分级的合格标准。40%和20%浓度镁合金浸提液中,IEC-6细胞的凋亡比例及Caspase-3活化度相对于对照组都增高,差异有统计学意义(P0.05),40%浓度组中,IEC-6细胞的凋亡比例及Caspase-3活化度相对于20%浓度组增高,差异有统计学意义(P0.05),说明Mg-6Zn合金浸提液在一定范围内处于较高浓度时易诱导IEC-6细胞的凋亡及Caspase-3的表达,且随浓度升高影响越大。  相似文献   

8.
探讨不同状况下全反式维甲酸对转染IGF—Ⅱ基因胃癌细胞生物学行为的影响。方法以人胃癌细胞系SGC7901细胞分别转染IGF—Ⅱ反义基因.以不同浓度全反式维甲酸处理,观察细胞生长曲线。以MTT法测细胞生长抑制,DAPI染色计数细胞凋亡。扫描及透视电镜观察细胞形态。结果在全反式维甲酸干预后,转染IGF—Ⅱ反义基因细胞凋亡指数上升,且与药物浓度正相关j细胞生长抑制;电镜显示细胞结构改变。结论反义基因IGF—Ⅱ转染胃癌后联合维甲酸可协同抑制胃癌细胞恶性表型,诱导细胞凋亡。  相似文献   

9.
利用二维切片数据重建三维结构,在医学领域有着重要作用。为了提高医学三维图像的重建速度和效果,在对用于构造等值面的MC(Marching Cubes)算法进行分析的基础上,提出了两种方法来提高重建速度和可视化效果。用两相邻样本点的中点代替多边形顶点的位置,并对等值面法向矢量场进行平滑,从而达到加快三维重建速度以及得到更好的平滑效果的目的。  相似文献   

10.
为了研究嵌合抗CD20基因工程抗体Fab‘的抗肿瘤活性及其抗肿瘤机制,利用^3H掺入法测定嵌合抗CD20Fab‘对Raji细胞生长的影响,结果显示嵌合抗CD20Fab‘对Raji细胞的生长具有抑制作用,利用流式细胞仪测定嵌合抗CD20Fab‘诱导Raji细胞凋亡作用,结果显示嵌合抗CD20Fab‘可诱导Raji细胞凋亡作用。这些实验结果证明嵌合抗CD20Fab‘通过诱导Raji细胞凋亡的机制抑制Raji细胞生长。  相似文献   

11.
Yip B  Fourguette DC  Long MB 《Applied optics》1986,25(21):3919-3923
The 3-D measurement of the gas concentration in a photoacoustically forced gas jet is described. A pulsed laser focused onto a laminar gas flow was used to trigger a localized disturbance which evolved with time. After a fixed time delay, the gas concentration in a 2-D cross section of the jet was measured by recording Rayleigh scattering from a second laser used to illuminate a thin sheet intersecting the flow. A series of these 2-D measurements made at the same time delay resulted in a full 3-D mapping of structures within the flow. Computer graphics enabled the subsequent reconstruction and visualization of the 3-D surfaces of constant concentration as well as the magnitude of the concentration gradient on such surfaces.  相似文献   

12.
This work describes some techniques developed for focused ion beam (FIB) serial sectioning and electron backscatter diffraction (EBSD) mapping of partially and fully recrystallized metals. A DualBeam™ platform was used to sequentially mill submicron slices of a material by FIB with the crystallographic features of each newly created surface characterized by EBSD. Two promising milling procedures are described which involve: (i) the generation of a small (∼ 10–50 μm) diameter whisker for subsequent serial sectioning perpendicular to its long axis, and (ii) more extensive FIB milling of a larger sample to generate a protruding rectangular-shaped volume at the free surface. The latter was found to be the more powerful method of serial sectioning as the initial preparation is slightly less tedious. Using both techniques, serial sectioning was carried out on both recrystallized iron and partly recrystallized nickel samples. The serial sectioning technique revealed a number of features of the recrystallizing grains in nickel that are not clearly evident in 2-D EBSD micrographs.  相似文献   

13.
Self-assembly of one-dimensional nanoscale building blocks into functional 2-D or 3-D complex superstructures has stimulated a great deal of interest. We report the synthesis and characterization of nanopolyhedrons assembled from ultrathin SnO(2) nanowires based on the sodium dodecyl sulfate (SDS)-assisted hydrothermal process. As-synthesized SnO(2) nanopolyhedrons have uniform diameters around 300 nm and are self-assembled by numerous ultrathin SnO(2) nanowires with diameters of 5-10 nm. The growth mechanism was also studied by investigating the samples synthesized at different reaction time. Thin films of the assembled SnO(2) nanopolyhedrons were configured as high performance sensors to detect methanol, ethanol, and acetone, which exhibited 1 ppm sensitivity, very fast response and recovery times (several seconds for different gases with concentrations of 1-200 ppm) to all the target gases and highly selective detection to acetone.  相似文献   

14.
3-dimension (3-D) printing technology is growing strongly with many applications, one of which is the garment industry. The application of human body models to the garment industry is necessary to respond to the increasing personalization demand and still guarantee aesthetics. This paper proposes a method to construct 3-D human models by applying deep learning. We calculate the location of the main slices of the human body, including the neck, chest, belly, buttocks, and the rings of the extremities, using pre-existing information. Then, on the positioning frame, we find the key points (fixed and unaltered) of these key slices and update these points to match the current parameters. To add points to a star slice, we use a deep learning model to mimic the form of the human body at that slice position. We use interpolation to produce sub-slices of different body sections based on the main slices to create complete body parts morphologically. We combine all slices to construct a full 3-D representation of the human body.  相似文献   

15.
The ability for early evaluation of therapeutic effects is a significant challenge in leukemia research. To address this challenge, we developed a novel electrochemical platform for ultrasensitive and selective detection of apoptotic cells in response to therapy. In order to construct the platform, a novel three-dimensional (3-D) architecture was initially fabricated after combining nitrogen-doped carbon nanotubes and gold nanoparticles via a layer-by-layer method. The formed architecture provided an effective matrix for annexin V with high stability and bioactivity to enhance sensitivity. On the basis of the specific recognition between annexin V and phosphatidylserine on the apoptotic cell membrane, the annexin V/3-D architecture interface showed a predominant capability for apoptotic cell capture. Moreover, a lectin-based nanoprobe was designed by noncovalent assembly of concanavalin A on CdTe quantum dots (QDs)-labeled silica nanospheres with poly(allylamine hydrochloride) as a linker. This nanoprobe incorporated both the specific carbohydrate recognition and the multilabeled QDs-based signal amplification. By coupling with the QDs-based nanoprobe and electrochemical stripping analysis, the proposed sandwich-type cytosensor showed an excellent analytical performance for the ultrasensitive detection of apoptotic cells (as low as 48 cells), revealing great potential toward the early evaluation of therapeutic effects.  相似文献   

16.
A new analytical modelling approach for the prediction of the stiffness of 3-D orthotropic laminated composites is given. The composite, which consists of stacked orthotropic layers which are in turn composed of a number of parallel unidirectional stripes, is assumed to be homogeneous and orthotropic macroscopically. The technique introduced is to discretise the representative unit cell of the composite into slices (layers) and then stripes (elements). The stiffness of each slice can then be obtained under the condition of isostrain or isostress. The final stiffness of the composite is formulated analytically by combining these slices. The model eliminates the inconsistency between macro- and micro-level strains and gives more realistic distributions of strain for the representative unit cell. The results demonstrate that the present model, which is both simple and computationally efficient, can give a very accurate prediction compared with data from experiments and some existing models.  相似文献   

17.
Quantum mechanical tunneling of electrons across ultrathin insulating oxide barriers has been studied extensively for decades due to its great potential in electronic‐device applications. In the few‐nanometers‐thick epitaxial oxide films, atomic‐scale structural imperfections, such as the ubiquitously existed one‐unit‐cell‐high terrace edges, can dramatically affect the tunneling probability and device performance. However, the underlying physics has not been investigated adequately. Here, taking ultrathin BaTiO3 films as a model system, an intrinsic tunneling‐conductance enhancement is reported near the terrace edges. Scanning‐probe‐microscopy results demonstrate the existence of highly conductive regions (tens of nanometers wide) near the terrace edges. First‐principles calculations suggest that the terrace‐edge geometry can trigger an electronic reconstruction, which reduces the effective tunneling barrier width locally. Furthermore, such tunneling‐conductance enhancement can be discovered in other transition metal oxides and controlled by surface‐termination engineering. The controllable electronic reconstruction can facilitate the implementation of oxide electronic devices and discovery of exotic low‐dimensional quantum phases.  相似文献   

18.
Gao F  Tanikawa Y  Zhao H  Yamada Y 《Applied optics》2002,41(34):7346-7358
Although a foil three-dimensional (3-D) reconstruction with both 3-D forward and inverse models provide, the optimal solution for diffuse optical tomography (DOT), because of the 3-D nature of photon diffusion in tissue, it is computationally costly for both memory requirement and execution time in a conventional computing environment. Thus in practice there is motivation to develop an image reconstruction algorithm with dimensional reduction based on some modeling approximations. Here we have implemented a semi-3-D modified generalized pulse spectrum technique for time-resolved DOT, where a two-dimensional (2-D) distribution of optical properties is approximately assumed, while we retain 3-D distribution of photon migration in tissue. We have validated the proposed algorithm by reconstructing 3-D structural test objects from both numerically simulated and experimental date. We demonstrate our algorithm by comparing it with the calibrated 2-D reconstruction that is in widespread use as a shortcut to 3-D imaging and proving that the semi-3-D algorithm outperforms the calibrated 2-D algorithm.  相似文献   

19.
Gao F  Poulet P  Yamada Y 《Applied optics》2000,39(31):5898-5910
A Newton-Raphson inversion algorithm has been extended for simultaneous absorption and scattering reconstruction of fully three-dimensional (3D) diffuse optical tomographic imaging from time-resolved measurements. The proposed algorithm is derived from the efficient computation of the Jacobian matrix of the forward model and uses either the algebraic reconstruction technique or truncated singular-value decomposition as the linear inversion tool. Its validation was examined with numerically simulated data from 3-D finite-element discretization models of tissuelike phantoms, with several combinations of geometric and optical properties, as well as two commonly used source-detector configurations. Our results show that the fully 3-D image reconstruction of an object can be achieved with reasonable quality when volumetric light propagation in tissues is considered, and temporal information from the measurements can be effectively employed. Also, we investigated the conditions under which 3-D issues could be approximately addressed with two-dimensional reconstruction algorithms and further demonstrated that these conditions are seldom predictable or attainable in practice. Thus the application of 3-D algorithms to realistic situations is necessary.  相似文献   

20.
We previously reported an ultrasonic strain measurement-based one-dimensional (1-D) shear modulus reconstruction technique using a regularization method for differential diagnosis of malignancies on human superficial tissues (e.g., breast tissues). Here, ultrasonic strain measurement-based 2-D and 3-D shear modulus reconstruction techniques are described, and the 1-D technique is reviewed and subsequently applied to various human in vivo tissues, including deeply situated tissues (e.g., liver). Because soft tissues are deformed in 3-D space by externally situated arbitrary mechanical sources, the accuracy of the low-dimensional (i.e., 1-D or 2-D) reconstructions is lower to that of 3-D reconstruction due to occurrence of erroneous reconstruction artifacts (i.e., the reconstructed modulus is different than reality). These artifacts are confirmed on simulated inhomogeneous cubic phantoms containing a spherical homogenous inclusion using numerically calculated deformation data. The superiority of quasi-real-time imaging of the shear modulus is then demonstrated by comparing it with conventional B-mode imaging and strain imaging from the standpoints of monitoring the effectiveness of minimally invasive thermal therapy as well as differential diagnosis. Because the 2-D and 3-D techniques require special ultrasonic (US) equipment, the 1-D technique using conventional US imaging equipment is used, even though erroneous artifacts will occur. Specifically, the 1-D technique is applied as a diagnostic tool for differentiating malignancies in human in vivo liver and breast tissue, and a monitoring technique for determining the effectiveness of interstitial electromagnetic wave (micro and rf) thermal therapy on human in vivo liver and calf in vitro liver. Even when using the 1-D technique, reconstructed shear moduli were confirmed to be a suitable measure for monitoring thermal treatment as well as differential diagnosis. These results are encouraging in that they will promote use of 2-D and 3-D reconstruction techniques.  相似文献   

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