Bias between MNI and Talairach coordinates analyzed using the ICBM-152 brain template

MNI coordinates determined using SPM2 and FSL/FLIRT with the ICBM-152 template were compared to Talairach coordinates determined using a landmark-based Talairach registration method (TAL). Analysis revealed a clear-cut bias in reference frames (origin, orientation) and scaling (brain size). Accordingly, ICBM-152 fitted brains were consistently larger, oriented more nose down, and translated slightly down relative to TAL fitted brains. Whole brain analysis of MNI/Talairach coordinate disparity revealed an ellipsoidal pattern with disparity ranging from zero at a point deep within the left hemisphere to greater than 1-cm for some anterior brain areas. MNI/Talairach coordinate disparity was generally less for brains fitted using FSL. The mni2tal transform generally reduced MNI/Talairach coordinate disparity for inferior brain areas but increased disparity for anterior, posterior, and superior areas. Coordinate disparity patterns differed for brain templates (MNI-305, ICBM-152) using the same fitting method (FSL/FLIRT) and for different fitting methods (SPM2, FSL/FLIRT) using the same template (ICBM-152). An MNI-to-Talairach (MTT) transform to correct for bias between MNI and Talairach coordinates was formulated using a best-fit analysis in one hundred high-resolution 3-D MR brain images. MTT transforms optimized for SPM2 and FSL were shown to reduced group mean MNI/Talairach coordinate disparity from a 5-13 mm to 1-2 mm for both deep and superficial brain sites. MTT transforms provide a validated means to convert MNI coordinates to Talairach compatible coordinates for studies using either SPM2 or FSL/FLIRT with the ICBM-152 template.     

Topographic approach to the study of the human body

Recent developments in medical imaging techniques such as ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI) have been explosive. These modalities provide 3D information about the human body and assess tissue damage in various pathological conditions. To complement the diagnostic usefulness of these imaging techniques, we have designed a system of topographic coordinates based on the principles of global projection cartography in which lines of latitude and longitudes are assigned to the surface of the human body. We designated the median sagittal plane as corresponding to the Greenwich Meridian (zero longitude) in global cartography. From the median sagittal plane (M0), vertical lines of longitude or "great circles" divide the body into 12 zones that are 30 degrees apart. Parallel lines of latitude are assigned according to surface anatomy landmarks. Studying the 3D reconstruction of anatomical structures is important for: 1) devising a system of coordinates; 2) allowing biomedical measurements to be made; and 3) drawing maps that may be useful in some clinical procedures (e.g., biopsies).     

Retinoic acid signaling in the brain marks formation of optic projections, maturation of the dorsal telencephalon, and function of limbic sites

As retinoic acid (RA) is known to regulate the expression of many neuronal proteins, it is likely to influence overall development and function of the brain; few particulars, however, are available about its role in neurobiological contexts due mainly to problems in RA detection. To ask whether the function of RA in the rostral brain is concentrated in particular neurobiological systems, we compared sites of RA synthesis and actions, as detected by RA signaling in reporter mice, for embryonic and adult ages. We found that most sites of RA actions in the forebrain do not colocalize with RA synthesis, consistent with a dominant RA supply by diffusion and the circulation. The changing RA patterns distinguish preferentially two complex functional schemes. (1) Within the visual system when the first optic axons grow toward their targets, RA signaling delineates the topographical adjustment of the retinal map, which is encoded in the coordinates of the visual world, to central visual maps, which are formed in the segmental brain coordinates. (2) The second scheme begins early in forebrain morphogenesis as a distinction of the dorsal telencephalon. With progressing development, and in the adult, the RA patterns then focus on widely distributed structures, most of which belong to the limbic system. These are sites in which emotional perception is combined with higher cognitive processes and in which normal function requires ongoing remodeling of synaptic connections, indicating that the developmental role of RA in promotion of neuronal differentiation programs continues in the adult brain for highly flexible neural circuits. J. Comp. Neurol. 470:297-316, 2004.     

痰涂片肺癌脱落细胞巴氏染色色度学定量研究

目的定量揭示痰涂片中肺癌脱落细胞巴氏染色的色度学特征,筛选对肺癌诊断分类有重要价值的色度学参数。方法取痰涂片中正常的柱状上皮细胞、鳞状上皮细胞、组织细胞和肺的鳞癌、腺癌、大细胞癌及小细胞癌细胞,用计算机图像分析技术分别测试上述7类细胞的色度学参数值,包括细胞的红、绿、蓝三基色(Rc、Gc、Bc)及其三基色系数(rc、gc、bc),核的红、绿、蓝三基色(Rn、Gn、Gn)及其三基色系数(rn、gn、bn)。结果正常细胞的Rc、Gc、Bc、rc、Rn、Gn、rn均高于癌细胞,bc、bn则低于癌细胞,差异均有统计学意义;在正常细胞中,SqE的Rc、Gc、Rn、Gn、Bc和Bn均为最高,CE的Gc、Rn、Gn、Bc和Bn最小,Rc为HC最小,差异均有统计学意义;在癌细胞中,大细胞癌的Rc、Gc、Rn、Gn、rc、rn均为最高,bc、bn则最低,差异均有统计学意义;上述7类细胞间均有部分参数的差异有统计学意义。结论巴氏染色痰涂片中脱落细胞的色度学参数Rc、Rn、Gc、Gn、Bc、Bn及rc、rn、gc、gn、bc、bn在不同类型细胞间有显著性差异,这些参数及其差异不但可用于判别鳞癌、腺癌、小细胞癌与大细胞癌细胞的研究,还可用于判别柱状上皮细胞、组织细胞与鳞状上皮细胞以及正常与肺癌细胞的研究。     

Cartesian coordinates scaffold stable spatial perception over time

Visual systems exploit temporal continuity principles to achieve stable spatial perception, manifested as the serial dependence and central tendency effects. These effects are posited to reflect a smoothing process whereby past and present information integrates over time to decrease noise and stabilize perception. Meanwhile, the basic spatial coordinate—Cartesian versus polar—that scaffolds the integration process in two-dimensional continuous space remains unknown. The spatial coordinates are largely related to the allocentric and egocentric reference frames and presumably correspond with early and late processing stages in spatial perception. Here, four experiments consistently demonstrate that Cartesian outperforms polar coordinates in characterizing the serial bias—serial dependence and central tendency effect—in two-dimensional continuous spatial perception. The superiority of Cartesian coordinates is robust, independent of task environment (online and offline task), experimental length (short and long blocks), spatial context (shape of visual mask), and response modality (keyboard and mouse). Taken together, the visual system relies on the Cartesian coordinates for spatiotemporal integration to facilitate stable representation of external information, supporting the involvement of allocentric reference frame and top-down modulation in spatial perception over long time intervals.     

基于“辨色论质”的百合制桔梗质量控制研究

目的 探究百合制桔梗“辨色论质”的实质,形成百合制桔梗科学的质量评价方法,并为其在线质量控制提供理论依据。方法 采用精密色差仪对桔梗和百合制桔梗的色度值进行测定,运用UPLC-ELSD建立桔梗和百合制桔梗指纹图谱,通过SPSS 21.0和Origin Pro 2021软件分析其色度值与共有峰之间的相关性,根据相关程度筛选色度相关峰并进行指认。运用软件MATLAB R2016a筛选隐含节点数,建立最优的“成分-色度”人工神经网络模型。结果 百合制桔梗共有12个共有峰,指认出6个色度相关成分,分别为王百合苷A(峰1)、王百合苷F(峰2)、王百合苷B(峰3)、桔梗皂苷E(峰5)、党参炔苷(峰6)、桔梗皂苷D(峰10)。桔梗皂苷E与色度值a^*、b^*呈正相关,王百合苷A、王百合苷F、王百合苷B等化学成分均与色度值呈负相关。通过隐含节点数筛选,发现隐含节点数为8时模型整体拟合程度最高,人工神经网络模型的均方根误差(root mean square error,RMSE)较小,R²最高(RMSE＝0.251 3,R²_all＝0.926 2),因此选择4-8-7作为模型最佳拓扑结构,经验证表明该模型预测结果良好。结论 证实百合制桔梗“辨色论质”的科学合理性,可将色度指标纳入百合制桔梗饮片质量评价体系中,为百合制桔梗的在线质量控制提供思路。     

基于坐标变换理论分析Ilizarov骨外固定架矫形力传导效率

文题释义：坐标变换理论：是指空间实体的位置描述,通过已有的Ilizarov骨外固定架和胫骨的空间几何关系和结构,建立各坐标系统的一一对应关系,将各矫形力从一种坐标系统变换到另一种坐标系统的过程,用来描述调节力、支撑力和牵张力之间的相互关系。 矫形力传导效率：是指将六维力传感器上z轴的实际数据和推导出的z轴矫治分力理论值的比值,其反映Ilizarov骨外固定架在矫治过程中将调节力和支撑力转换为断骨端牵张力的效率,其结果可评估外固定架的矫治效果以及为矫治手术的精准调控提供参考。 背景：Ilizarov骨外固定架力传导机制的研究对膝内外翻、胫骨骨折等临床畸形矫治手术具有重要意义。 目的：分析胫骨矫治过程中Ilizarov骨外固定架的力传导机制和各矫形力变化情况,客观评价外固定架整体使用效果。 方法：根据骨外固定器的构型,基于坐标变换理论建立矫形力矩阵关系式,得到调节力、支撑力和牵张力之间的数学转换关系。搭建专用实验台,以羊胫骨为实验对象进行胫骨矫治实验,测得骨外固定架调节杆上调节力、支撑杆上的支撑力及断骨处的牵张力,计算得出断骨处的牵张力理论值,与六维力传感器测得的牵张力实际值对比,得出矫治过程的力传导效率变化曲线。 结果与结论：①在矫治过程中,Ilizarov骨外固定架的结构构型导致其调节杆和支撑杆存在相互作用和制约的情况,当某一调节力增大时另一调节力将出现下降的趋势;②力传导效率在前期存在较大幅度的增大,然后稳定在50%上下波动,实验结果可评估外固定架的整体矫治效果;③由于力传导过程中的损耗,断骨处的牵张力理论计算和实验结果曲线存在数值上的差别,但由实验结果可知,调节力、支撑力、牵张力理论值和牵张力实际值的整体力变化趋势基本一致,说明理论计算和实验结果的有效性,该实验量化评估结果可为Ilizarov骨外固定架构型的优化设计和胫骨矫治手术的精准调控提供参考。 ORCID: 0000-0003-1101-3109(胡湘宇) 中国组织工程研究杂志出版内容重点：人工关节;骨植入物;脊柱;骨折;内固定;数字化骨科;组织工程     

Cross-polarized excitons in carbon nanotubes

Polarization of low-lying excitonic bands in finite-size semiconducting single-walled carbon nanotubes (SWNTs) is studied by using quantum-chemical methodologies. Our calculations elucidate properties of cross-polarized excitons, which lead to the transverse optical absorption of nanotubes and presumably couple to intermediate-frequency modes recently observed in resonance Raman excitation spectroscopy. We identify up to 12 distinct excitonic transitions below the second fundamental band associated with the E(22) van Hove singularity. Calculations for several chiral SWNTs distinguish the optically active "bright" excitonic band polarized parallel to the tube axis and several optically "weak" cross-polarized excitons. The rest are optically (near) forbidden "dark" transitions. An analysis of the transition density matrices related to excitonic bands provides detailed information about delocalization of excitonic wavefunction along the tube. Utilization of the natural helical coordinate system accounting for the tube chirality allows one to disentangle longitudinal and circumferential components. The distribution of the transition density matrix along a tube axis is similar for all excitons. However, four parallel-polarized excitons associated with the E(11) transition are more localized along the circumference of a tube, compared with others related to the E(12) and E(21) cross-polarized transitions. Calculated splitting between optically active parallel- and cross-polarized transitions increases with tube diameter, which compares well with experimental spectroscopic data.     

广陈皮的外观颜色客观量化及其陈化年份判别模型的建立

目的:依据色度分析原理对广陈皮外观颜色进行客观量化研究,为广陈皮的陈化年份鉴别建立新方法。方法:采用色彩色差计对广陈皮外观颜色进行客观量化研究。采用非参数检验、秩相关检验法和判别分析等统计学方法对陈化年份与L*(明度值),a*(红绿分量值),b*(黄蓝分量值)之间的相关性进行分析。结果:不同年份广陈皮的色度值有显著性差异,且L*,a*,b*与陈化年份之间分别存在线性相关关系。建立了基于L*,a*,b*的广陈皮陈化年份的数学判别模型,陈化年份=-43.637L*+5.351a*+42.430b*+30.790。结论:建立的客观量化方法稳定可行,为广陈皮的陈化年份鉴别提供了一种客观量化方法,可避免因传统人为鉴别方法所带来的误差。     

半夏炮制品相对毒性标示模型的探究

目的 以生品半夏Pinellia ternata毒性大小为标准,寻找标示半夏炮制品相对毒性大小的方法及相对毒性大小与指标成分间的关系.方法 按照《中国药典》2020年版一部方法对半夏生品进行质量检查;将影响半夏炮制品毒性的4个因素(白矾用量、生姜用量、蒸煮时间、蒸煮温度)进行混合均匀设计,建立正棱锥降维模型;将上述4个...